@article {32192, title = {Culture, conformity, and carbon? A multi-country analysis of heating and cooling practices in office buildings}, journal = {Energy Research \& Social Science}, volume = {61}, year = {2020}, month = {Jan-03-2020}, pages = {101344}, abstract = {

This study investigates human-building interaction in office spaces across multiple countries including Brazil, Italy, Poland, Switzerland, the United States, and Taiwan. We analyze social-psychological, contextual, and demographic factors to explain cross-country differences in adaptive thermal actions (i.e. cooling and heating behaviors) and conformity to the norms of sharing indoor environmental control features, an indicator of energy consumption. Specifically, personal adjustments such as putting on extra clothes are generally preferred over technological solutions such as adjusting thermostats in reaction to thermal discomfort. Social-psychological factors including attitudes, perceived behavioral control, injunctive norms, and perceived impact of indoor environmental quality on work productivity influence occupants{\textquoteright} intention to conform to the norms of sharing environmental control features. Lastly, accessibility to environmental control features, office type, gender, and age are also important factors. These findings demonstrate the roles of social-psychological and certain contextual factors in occupants{\textquoteright}
interactions with building design as well as their behavior of sharing environmental control features, both of which significantly influence building energy consumption, and thus, broader decarbonization.

}, issn = {22146296}, doi = {10.1016/j.erss.2019.101344}, author = {Chen, Chien-fei and Tianzhen Hong and de Rubens, Gerardo Zarazua and Yilmaz, Selin and Bandurski, Karol and B{\'e}lafi, Zs{\'o}fia Deme and De Simone, Marilena and Bavaresco, Mateus Vin{\'\i}cius and Wang, Yu and Liu, Pei-ling and Barthelmes, Verena M. and Adams, Jacqueline and D{\textquoteright}Oca, Simona and Przybylski, {\L}ukasz} } @article {32166, title = {Ten questions on urban building energy modeling}, journal = {Building and Environment}, volume = {168}, year = {2020}, month = {Jan-01-2020}, pages = {106508}, abstract = {

Buildings in cities consume up to 70\% of all primary energy. To achieve cities{\textquoteright} energy and climate goals, it is necessary to reduce energy use and associated greenhouse gas emissions in buildings through energy conservation and efficiency improvements. Computational tools empowered with rich urban datasets can model performance of buildings at the urban scale to provide quantitative insights for stakeholders and inform their decision making on urban energy planning, as well as building energy retrofits at scale, to achieve efficiency, sustainability, and resilience of urban buildings.
Designing and operating urban buildings as a group (from a city block to a district to an entire city) rather than as single individuals requires simulation and optimization to account for interactions among buildings and between buildings and their surrounding urban environment, and for district energy systems serving multiple buildings with diverse thermal loads across space and time. When hundreds or more buildings are involved in typical urban building energy modeling (UBEM) to estimate annual energy demand, evaluate design or retrofit options, and quantify impacts of extreme weather events or climate change, it is crucial to integrate urban datasets and UBEM tools in a seamless automatic workflow with cloud or high-performance computing for users including urban planners, designers and researchers.
This paper presents ten questions that highlight significant UBEM research and applications. The proposed answers aim to stimulate discussion and provide insights into the current and future research on UBEM, and more importantly, to inspire new and important questions from young researchers in the field.

}, issn = {03601323}, doi = {10.1016/j.buildenv.2019.106508}, author = {Tianzhen Hong and Chen, Yixing and Luo, Xuan and Luo, Na and Lee, Sang Hoon} } @article {31987, title = {Assessing the Potential to Reduce U.S. Building CO2 Emissions 80\% by 2050}, journal = {Joule}, year = {2019}, month = {08/2019}, abstract = {

Buildings are responsible for 36\% of CO2 emissions in the United States and will thus be integral to climate change mitigation; yet, no studies have comprehensively assessed the potential long-term CO2 emissions reductions from the U.S. buildings sector against national goals in a way that can be regularly updated in the future. We use Scout, a reproducible and granular model of U.S. building energy use, to investigate the potential for the U.S. buildings sector to reduce CO2 emissions 80\% by 2050, consistent with the U.S. Mid-Century Strategy. We find that a combination of aggressive efficiency measures, electrification, and high renewable energy penetration can reduce CO2 emissions by 72\%{\textendash}78\% relative to 2005 levels, just short of the target. Results are sufficiently disaggregated by technology and end use to inform targeted building energy policy approaches and establish a foundation for continual reassessment of technology development pathways that drive significant long-term emissions reductions.

}, keywords = {Building energy efficiency, decarbonization, electrification, emissions, energy models, energy policy analysis, national climate goals, pathways building stock}, doi = {10.1016/j.joule.2019.07.013}, author = {Jared Langevin and Chioke B. Harris and Janet L. Reyna} } @article {32157, title = {Assessment of occupant-behavior-based indoor air quality and its impacts on human exposure risk: A case study based on the wildfires in Northern California}, journal = {Science of The Total Environment}, volume = {686}, year = {2019}, month = {Jan-10-2019}, pages = {1251 - 1261}, abstract = {

The recent wildfires in California, U.S., have caused not only significant losses to human life and property, but also serious environmental and health issues. Ambient air pollution from combustion during the fires could increase indoor exposure risks to toxic gases and particles, further exacerbating respiratory conditions. This work aims at addressing existing knowledge gaps in understanding how indoor air quality is affected by outdoor air pollutants during wildfires{\textemdash}by taking into account occupant behaviors (e.g., movement, operation of windows and air-conditioning) which strongly influence building performance and occupant comfort. A novel modeling framework was developed to simulate the indoor exposure risks considering the impact of occupant behaviours by integrating building energy and occupant behaviour modeling with computational fluid dynamics simulation. Occupant behaviors were found to exert significant impacts on indoor air flow patterns and pollutant concentrations, based on which, certain behaviors are recommended during wildfires. Further, the actual respiratory injury level under such outdoor conditions was predicted. The modeling framework and the findings enable a deeper understanding of the actual health impacts of wildfires, as well as informing strategies for mitigating occupant health risk during wildfires

}, keywords = {computational fluid dynamics siumlation, human exposure risk, indoor air quality, NAPA wildfire, occupant behavior, respiratory injury}, issn = {00489697}, doi = {10.1016/j.scitotenv.2019.05.467}, author = {Luo, Na and Weng, Wenguo and Xu, Xiaoyu and Tianzhen Hong and Fu, Ming and Sun, Kaiyu} } @article {32160, title = {Cross-source sensing data fusion for building occupancy prediction with adaptive lasso feature filtering}, journal = {Building and Environment}, volume = {162}, year = {2019}, month = {Jan-09-2019}, pages = {106280}, abstract = {

Fusing various sensing data sources can significantly improve the accuracy and reliability of building occupancy detection. Fusing environmental sensors and wireless network signals are seldom studied for its computational and technical complexity. This study aims to propose an integrated adaptive lasso model that is able to extract critical data features for environmental and Wi-Fi probe dual sensing sources. Through rapid feature extraction and process simplification, the proposed method aims to improve the computational efficiency of occupancy detecting models. To validate the proposed model, an onsite experiment was conducted to examine two occupancy data resolutions, (real-time and four-level occupancy resolutions). The results suggested that, among all twelve features, eight features are most relevant. The mean absolute error of the real-time occupancy can be reduced to 2.18 and F1_accuracy is about 84.36\% for the four-level occupancy.

}, keywords = {data fusion, Feature selection, Machine learning, occupancy prediction, Physics-based model}, issn = {03601323}, doi = {10.1016/j.buildenv.2019.106280}, author = {Wang, Wei and Tianzhen Hong and Xu, Ning and Xu, Xiaodong and Chen, Jiayu and Shan, Xiaofang} } @article {31667, title = {Data fusion in predicting internal heat gains for office buildings through a deep learning approach}, journal = {Applied Energy}, volume = {240}, year = {2019}, month = {02/2019}, pages = {386 - 398}, abstract = {

Heating, Ventilation, and Air Conditioning (HVAC) is a major energy consumer in buildings. The predictive control has demonstrated a potential to reduce HVAC energy use. To facilitate predictive HVAC control, internal heat gains prediction is required. In this study, we applied Long Short-Term Memory Networks, a special form of deep neural network, to predict miscellaneous electric loads, lighting loads, occupant counts and internal heat gains in two United States office buildings. Compared with the predetermined schedules used in American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standard 90.1, the Long Short-Term Memory Networks method could reduce the prediction errors of internal heat gains from 12\% to 8\% in Building A, and from 26\% to 16\% in Building B. It was also found that for internal heat gains prediction, miscellaneous electric loads is a more important feature than occupant counts for two reasons. First, miscellaneous electric loads is the best proxy variable for internal heat gains, as it is the major component of and has the highest correlation coefficient with the internal heat gains. Second, miscellaneous electric loads contain valuable information to predict occupant count, while occupant count could not help improve miscellaneous electric loads prediction. These findings could help researchers and practitioners select the most relevant features to more accurately predict internal heat gains for the implementation of predictive HVAC control in buildings.

}, keywords = {data fusion, deep learning, Internal heat gains, Miscellaneous electric loads, Occupant count, Predictive control}, issn = {03062619}, doi = {10.1016/j.apenergy.2019.02.066}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0306261919303630}, author = {Zhe Wang and Tianzhen Hong and Mary Ann Piette} } @article {31312, title = {Development of city buildings dataset for urban building energy modeling}, journal = {Energy and Buildings}, volume = {183}, year = {2019}, month = {11/2018}, pages = {252 - 265}, abstract = {

Urban building energy modeling (UBEM) is becoming a proven tool to support energy efficiency programs for buildings in cities. Development of a city-scale dataset of the existing building stock is a critical step of UBEM to automatically generate energy models of urban buildings and simulate their performance. This study introduces data needs, data standards, and data sources to develop city building datasets for UBEM. First, a literature review of data needs for UBEM was conducted. Then, the capabilities of the current data standards for city building datasets were reviewed. Moreover, the existing public data sources from several pioneer cites were studied to evaluate whether they are adequate to support UBEM. The results show that most cities have adequate public data to support UBEM; however, the data are represented in different formats without standardization, and there is a lack of common keys to make the data mapping easier. Finally, a case study is presented to integrate the diverse data sources from multiple city departments of San Francisco. The data mapping process is introduced and discussed. It is recommended to use the unique building identifiers as the common keys in the data sources to simplify the data mapping process. The integration methods and workflow are applied to other U.S. cities for developing the city-scale datasets of their existing building stock, including San Jose, Los Angeles, and Boston.

}, keywords = {City building dataset, CityGML, Data mapping, Data standards, Urban Building Energy Modeling}, issn = {03787788}, doi = {10.1016/j.enbuild.2018.11.008}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0378778818316852https://api.elsevier.com/content/article/PII:S0378778818316852?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0378778818316852?httpAccept=text/plain}, author = {Yixing Chen and Tianzhen Hong and Xuan Luo and Barry Hooper} } @article {31670, title = {Forecasting district-scale energy dynamics through integrating building network and long short-term memory learning algorithm}, journal = {Applied Energy}, volume = {248}, year = {2019}, month = {04/2019}, pages = {217 - 230}, abstract = {

With the development of data-driven techniques, district-scale building energy prediction has attracted increasing attention in recent years for revealing energy use patterns and reduction potentials. However, data acquisition in large building groups is difficult and adjacent buildings also interact with each other. To reduce data cost and incorporate the inter-building impact with the data-driven building energy model, this study proposes a deep learning predictive approach that fuses the building network model with a long short-term memory learning model for district-scale building energy modeling. The building network was constructed based on correlations between the energy use intensity of buildings, which can significantly reduce the computational complexity of the deep learning models for energy dynamic prediction. Five typical building groups with energy use data from 2015 to 2018 on two institutional campuses were selected to perform the validation experiment with TensorFlow. Based on the prediction error assessments, the results suggest that for total building energy use intensity prediction, the proposed model can achieve a mean absolute percentage error of 6.66\% and a root mean square error of 0.36 kWh/m2, compared to 12.05\% and 0.63 kWh/m2 of the conventional artificial neural network model and to 11.06\% and 0.89 kWh/m2 for the support vector regression model.

}, keywords = {Building Energy Modeling, Building network, Data-driven prediction, District-scale, Long short-term memory networks}, issn = {03062619}, doi = {10.1016/j.apenergy.2019.04.085}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0306261919307494}, author = {Wei Wang and Tianzhen Hong and Xiaodong Xu and Jiayu Chen and Ziang Liu and Ning Xu} } @article {31665, title = {Incorporating machine learning with building network analysis to predict multi-building energy use}, journal = {Energy and Buildings}, volume = {186}, year = {2019}, month = {06/2019}, pages = {80 - 97}, abstract = {

Predicting multi-building energy use at campus or city district scale has recently gained more attention; and more researchers have started to define reference buildings and study inter-impact between building groups. However, how to integrate the relationship to define reference buildings and predict multi-building energy use, using significantly less amount of building data and reducing complexity of prediction models, remains an open research question. To resolve this, this study proposed a novel method to predict multi-building energy use by integrating a social network analysis (SNA) with an Artificial Neural Network (ANN) technique. The SNA method was used to establish a building network (BN) by identifying reference buildings and determine correlations between reference buildings and non-reference buildings. The ANN technique was applied to learn correlations and historical building energy use, and then used to predict multi-building energy use. To validate the SNA-ANN method, 17 buildings in the Southeast University campus, located in Nanjing, China, were studied. These buildings have three years of actual monthly electricity use data and were grouped into four types: office, educational, laboratory, and residential. The results showed the integrated SNA-ANN method achieved average prediction accuracies of 90.67\% for the office group, 90.79\% for the educational group, 92.34\% for the laboratory group, and 83.32\% for the residential group. The results demonstrated the proposed SNA-ANN method achieved an accuracy of 90.28\% for the predicted energy use for all building groups. Finally, this study provides insights into advancing the interdisciplinary research on multi-building energy use prediction.

}, keywords = {Artificial neural networks, Building network, cold winter and hot summer climate, Energy use prediction, Machine learning}, issn = {03787788}, doi = {10.1016/j.enbuild.2019.01.002}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0378778818319765}, author = {Xiaodong Xu and Wei Wang and Tianzhen Hong and Jiayu Chen} } @article {31671, title = {Inferring occupant counts from Wi-Fi data in buildings through machine learning}, journal = {Building and Environment}, volume = {158}, year = {2019}, month = {05/2019}, pages = {281 - 294}, abstract = {

An important approach to curtail building energy consumption is to optimize building control based on occupancy information. Various studies proposed to estimate occupant counts through different approaches and sensors. However, high cost and privacy concerns remain as major barriers, restricting the practice of occupant count detection. In this study, we propose a novel method utilizing data from widely deployed Wi-Fi infrastructure to infer occupant counts through machine learning. Compared with the current indirect measurement methods, our method improves the performance of estimating people count: (1) we avoid privacy concerns by anonymizing and reshuffling the MAC addresses on a daily basis; (2) we adopted a heuristic feature engineer approach to cluster connected devices into different types based on their daily connection duration. We tested the method in an office building located in California. In an area with an average occupancy of 22{\textendash}27 people and a peak occupancy of 48{\textendash}74 people, the root square mean error on the test set is less than four people. The error is within two people counts for more than 70\% of estimations, and less than six counts for more than 90\% of estimations, indicating a relatively high accuracy. The major contribution of this study is proposing a novel and accurate approach to detect occupant counts in a non-intrusive way, i.e., utilizing existing Wi-Fi infrastructure in buildings without requiring the installation of extra hardware or sensors. The method we proposed is generic and could be applied to other commercial buildings to infer occupant counts for energy efficient building control.

}, keywords = {Building control, Machine learning, Occupancy estimation, Occupant count, Random forest, Wi-Fi data}, issn = {03601323}, doi = {10.1016/j.buildenv.2019.05.015}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0360132319303336}, author = {Zhe Wang and Tianzhen Hong and Mary Ann Piette and Marco Pritoni} } @article {31668, title = {Integrating physics-based models with sensor data: An inverse modeling approach}, journal = {Building and Environment}, volume = {154}, year = {2019}, month = {05/2019}, pages = {23 - 31}, abstract = {

Physics-based building energy models (e.g., EnergyPlus) rely on some unknown input parameters (e.g., zone air infiltration) that are hard to measure, leading to uncertainty in simulation results especially for existing buildings with varying operating conditions. With the increasing deployment of smart thermostats, zone air temperature data are readily available, posing a new opportunity for building energy modeling if such data can be harnessed. This study presents a novel inverse modeling approach which inverses the zone air heat balance equation and uses the measured zone air temperature to analytically calculate the zone air infiltration rate and zone internal thermal mass (e.g., furniture, interior partitions), which are two important model parameters with great variability and difficult to measure. This paper introduces the technical concept and algorithms of the inverse models, their implementation in EnergyPlus, and verification using EnergyPlus simulated building performance data. The inverse modeling approach provides new opportunities for integrating data from massive IoT sensors and devices to enhance the accuracy of simulation results which are used to inform decision making on energy retrofits and efficiency improvements of existing buildings.

}, keywords = {building performance simulation, energyplus, infiltration, internal thermal mass, inverse model, sensor data}, issn = {03601323}, doi = {10.1016/j.buildenv.2019.03.006}, url = {https://linkinghub.elsevier.com/retrieve/pii/S036013231930160X}, author = {Tianzhen Hong and Sang Hoon Lee} } @article {32156, title = {An inverse approach to solving zone air infiltration rate and people count using indoor environmental sensor data}, journal = {Energy and Buildings}, volume = {198}, year = {2019}, month = {Jan-09-2019}, pages = {228 - 242}, abstract = {

Physics-based simulation of energy use in buildings is widely used in building design and performance rating, controls design and operations. However, various challenges exist in the modeling process. Model parameters such as people count and air infiltration rate are usually highly uncertain, yet they have significant impacts on the simulation accuracy. With the increasing availability and affordability of sensors and meters in buildings, a large amount of measured data has been collected including indoor environmental parameters, such as room air dry-bulb temperature, humidity ratio, and CO2 concentration levels. Fusing these sensor data with traditional energy modeling poses new opportunities to improve simulation accuracy. This study develops a set of physics-based inverse algorithms which can solve the highly uncertain and hard-to-measure building parameters such as zone-level people count and air infiltration rate. A simulation-based case study is conducted to verify the inverse algorithms implemented in EnergyPlus covering various sensor measurement scenarios and different modeling use cases. The developed inverse models can solve the zone people count and air infiltration at sub-hourly resolution using the measured zone air temperature, humidity and/or CO2 concentration given other easy-to-measure model parameters are known.

}, keywords = {energyplus, infiltration, Inverse problems, people count, sensor data, zone air parameters}, issn = {03787788}, doi = {10.1016/j.enbuild.2019.06.008}, author = {Li, Han and Hong, Tianzhen and Sofos, Marina} } @article {32165, title = {Learning occupants{\textquoteright} indoor comfort temperature through a Bayesian inference approach for office buildings in United States}, journal = {Renewable and Sustainable Energy Reviews}, year = {2019}, month = {Jan-11-2019}, pages = {109593}, abstract = {

A carefully chosen indoor comfort temperature as the thermostat set-point is the key to optimizing building energy use and occupants{\textquoteright} comfort and well-being. ASHRAE Standard 55 or ISO Standard 7730 uses the PMV-PPD model or the adaptive comfort model that is based on small-sized or outdated sample data, which raises questions on whether and how ranges of occupant thermal comfort temperature should be revised using more recent larger-sized dataset. In this paper, a Bayesian inference approach has been used to derive new occupant comfort temperature ranges for U.S. office buildings using the ASHRAE Global Thermal Comfort Database. Bayesian inference can express uncertainty and incorporate prior knowledge. The comfort temperatures were found to be higher and less variable at cooling mode than at heating mode, and with significant overlapped variation ranges between the two modes. The comfort operative temperature of occupants varies between 21.9 and 25.4{\textdegree}C for the cooling mode with a median of 23.7{\textdegree}C, and between 20.5 and 24.9{\textdegree}C for the heating mode with a median of 22.7{\textdegree}C. These comfort temperature ranges are similar to the current ASHRAE standard 55 in the heating mode but 2-3{\textdegree}C lower in the cooling mode. The results of this study could be adopted as more realistic thermostat set-points in building design, operation, control optimization, energy performance analysis, and policymaking.

}, issn = {13640321}, doi = {10.1016/j.rser.2019.109593}, author = {Wang, Zhe and Hong, Tianzhen} } @article {31662, title = {Linking energy-cyber-physical systems with occupancy prediction and interpretation through WiFi probe-based ensemble classification}, journal = {Applied Energy}, volume = {236}, year = {2019}, month = {02/2019}, pages = {55 - 69}, abstract = {

With rapid advances in sensing and digital technologies, cyber-physical systems are regarded as the most prominent platforms to improve building design and management. Researchers investigated the possibility of integrating energy management system with cyber-physical systems as energy-cyber-physical systems to promote building energy management. However, minimizing energy consumption while fulfilling building functions for energy-cyber-physical systems is challenging due to the dynamics of building occupants. As occupant behavior is one major source of uncertainties for energy management, ignoring it often results in energy wastes caused by overheating and overcooling as well as discomfort due to insufficient thermal and ventilation services. To mitigate such uncertainties, this study proposed an occupancy linked energy-cyber-physical system that incorporates WiFi probe-based occupancy detection. The proposed framework utilized ensemble classification algorithms to extract three types of occupancy information. It creates a data interface to link energy management system and cyber-physical systems and allows automated occupancy detection and interpretation through assembling multiple weak classifiers for WiFi signals. A validation experiment in a large office room was conducted to examine the performance of the proposed occupancy linked energy-cyber-physical systems. The experiment and simulation results suggest that, with a proper classifier and occupancy type, the proposed model can potentially save about 26.4\% of energy consumption from the cooling and ventilation demands.

}, keywords = {Building occupancy, Energy-Cyber-Physical Systems, ensemble algorithm, Wi-Fi probe technology}, issn = {03062619}, doi = {10.1016/j.apenergy.2018.11.079}, author = {Wei Wang and Tianzhen Hong and Nan Li and Ryan Qi Wang and Jiayu Chen} } @article {31669, title = {A novel approach for selecting typical hot-year (THY) weather data}, journal = {Applied Energy}, volume = {242}, year = {2019}, month = {03/2019}, pages = {1634 - 1648}, abstract = {

The global climate change has resulted in not only warmer climate conditions but also more frequent extreme weather events, such as heat waves. However, the impact of heat waves on the indoor environment has been investigated in a limited manner. In this research, the indoor thermal environment is analyzed using a building performance simulation tool for a typical residential building in multiple cities in China, over a time period of 60 years using actual measured weather data, in order to gain a better understanding of the effect of heat wave events. The simulation results were used to analyze the indoor environment during hot summers. A new kind of weather data referred to as the typical hot year was defined and selected based on the simulated indoor environment during heat waves. The typical hot-year weather data can be used to simulate the indoor environment during extreme heat events and for the evaluation of effective technologies and strategies to mitigate against the impact of heat waves on the energy demand of buildings and human health. The limitations of the current study and future work are also discussed.

}, keywords = {Actual weather data, dest, Heat wave, Multiyear simulation, Residential indoor thermal environment, Typical hot year}, issn = {03062619}, doi = {10.1016/j.apenergy.2019.03.065}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0306261919304659}, author = {Siyue Guo and Da Yan and Tianzhen Hong and Chan Xiao and Ying Cui} } @article {31673, title = {OPEN COMPUTING INFRASTRUCTURE FOR SHARING DATA ANALYTICS TO SUPPORT BUILDING ENERGY SIMULATIONS}, year = {2019}, month = {08/2019}, abstract = {

Building energy simulation plays an increasingly important role in building design and operation. In this paper, we present an open computing infrastructure, Virtual Information Fabric Infrastructure (VIFI), that allows building designers and engineers to enhance their simulations by combining empirical data with diagnostic or prognostic models. Based on the idea of dynamic data-driven application systems (DDDAS), the VIFI infrastructure complements conventional data-centric sharing strategies and addresses key data sharing concerns such as the privacy of building occupants. To demonstrate the potential of the VIFI infrastructure, we simulate an empirically-derived lighting schedule in the U.S. Department of Energy{\textquoteright}s small office building reference model. We use the case study simulation to explore the possibility and potential of integrating data-centric and analytic-centric sharing strategies; the method of combining empirical data with simulations; the creation, sharing, and execution of analytics using VIFI; and the impact of incorporating empirical data on energy simulations. While the case study reveals clear advantages of the VIFI data infrastructure, research questions remain surrounding the motivation and benefits for sharing data, the metadata that are required to support the composition of analytics, and the performance metrics that could be used in assessing the applications of VIFI.

}, author = {Omer T. Karaguzel and Mohammed Elshambakey and Yimin Zhu and Tianzhen Hong} } @article {31664, title = {Performance-driven optimization of urban open space configuration in the cold-winter and hot-summer region of China}, journal = {Building Simulation}, volume = {12}, year = {2019}, month = {03/2019}, pages = {411 - 424}, abstract = {

Urbanization has led to changes in urban morphology and climate, while urban open space has become an important ecological factor for evaluating the performance of urban development. This study presents an optimization approach using computational performance simulation. With a genetic algorithm using the Grasshopper tool, this study analyzed the layout and configuration of urban open space and its impact on the urban micro-climate under summer and winter conditions. The outdoor mean Universal Thermal Climate Index (UTCI) was applied as the performance indicator for evaluating the quality of the urban micro-climate. Two cases{\textemdash}one testbed and one real urban block in Nanjing, China{\textemdash}were used to validate the computer-aided simulation process. The optimization results in the testbed showed UTCI values varied from 36.5 to 37.3 {\textdegree}C in summer and from -4.9 to -1.9 {\textdegree}C in winter. In the case of the real urban block, optimization results show, for summer, although the average UTCI value increased by 0.6 {\textdegree}C, the average air velocity increased by 0.2 m/s; while in winter, the average UTCI value increased by 1.7 {\textdegree}C and the average air velocity decreased by 0.2 m/s. These results demonstrate that the proposed computer-aided optimization process can improve the thermal comfort conditions of open space in urban blocks. Finally, this study discusses strategies and guidelines for the layout design of urban open space to improve urban environment comfort.

}, issn = {1996-3599}, doi = {10.1007/s12273-019-0510-z}, url = {http://link.springer.com/10.1007/s12273-019-0510-zhttp://link.springer.com/content/pdf/10.1007/s12273-019-0510-z.pdfhttp://link.springer.com/content/pdf/10.1007/s12273-019-0510-z.pdfhttp://link.springer.com/article/10.1007/s12273-019-0510-z/fulltext.html}, author = {Xiaodong Xu and Yifan Wu and Wei Wang and Tianzhen Hong and Ning Xu} } @article {31672, title = {Predicting plug loads with occupant count data through a deep learning approach}, journal = {Energy}, volume = {181}, year = {2019}, month = {05/2019}, pages = {29 - 42}, abstract = {

Predictive control has gained increasing attention for its ability to reduce energy consumption and improve occupant comfort in buildings. The plug loads prediction is a key component for the predictive building controls, as plug loads is a major source of internal heat gains in buildings. This study proposed a novel method to apply the Long-Short-Term-Memory (LSTM) Network, a special form of Recurrent Neural Network, to predict plug loads. The occupant count and the time have been confirmed to drive the plug load profile and thus selected as the features for the plug load prediction. The LSTM network was trained and tested with ground truth occupant count data collected from a real office building in Berkeley, California. Results from the LSTM network markedly improve the prediction accuracy compared with traditional linear regression methods and the classical Artificial Neural Network. 95\% of 1-h predictions from LSTM network are within {\textpm}1 kW of the actual plug loads, given the average plug loads during the office hour is 8.6 kW. The CV(RMSE) of the predicted plug load is 11\% for the next hour, and 20\% for the next 8 h. Lastly, we compared four prediction approaches with the office building we monitored: LSTM vs. ARIMA, with occupant counts vs. without occupant counts. It was found, the prediction error of the LSTM approach is around 4\% less than the ARIMA approach. Using occupant counts as an exogenous input could further reduce the prediction error by 5\%{\textendash}6\%. The findings of this paper could shed light on the plug load prediction for building control optimizations such as model-predictive control.

}, keywords = {deep learning, Long short term memory network, Occupant count, Plug loads, prediction, Predictive control}, issn = {03605442}, doi = {10.1016/j.energy.2019.05.138}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0360544219310205}, author = {Zhe Wang and Tianzhen Hong and Mary Ann Piette} } @conference {31980, title = {Prototyping the BOPTEST Framework for Simulation-Based Testing of Advanced Control Strategies in Buildings}, booktitle = {IBPSA Building Simulation 2019}, year = {2019}, address = {Rome, Italy}, abstract = {

Advanced control strategies are becoming increasingly necessary in buildings in order to meet and balance requirements for energy efficiency, demand flexibility, and occupant comfort. Additional development and widespread adoption of emerging control strategies, however, ultimately require low implementation costs to reduce payback period and verified performance to gain control vendor, building owner, and operator trust. This is difficult in an already first-cost driven and risk-averse industry. Recent innovations in building simulation can significantly aid in meeting these requirements and spurring innovation at early stages of development by evaluating performance, comparing state-of-the-art to new strategies, providing installation experience, and testing controller implementations. This paper presents the development of a simulation framework consisting of test cases and software platform for the testing of advanced control strategies (BOPTEST - Building Optimization Performance Test). The objectives and requirements of the framework, components of a test case, and proposed software platform architecture are described, and the framework is demonstrated with a prototype implementation and example test case.

}, keywords = {benchmarking, building simulation, Model predictive control, software development}, author = {David Blum and Filip Jorissen and Sen Huang and Yan Chen and Javier Arroyo and Kyle Benne and Yanfei Li and Valentin Gavan and Lisa Rivalin and Lieve Helsen and Draguna Vrabie and Michael Wetter and Marina Sofos} } @article {31547, title = {Quayside Energy Systems Analysis}, year = {2019}, month = {03/2019}, keywords = {District Heating and cooling, modelica}, author = {Michael Wetter and Jianjun Hu} } @article {32159, title = {Revealing Urban Morphology and Outdoor Comfort through Genetic Algorithm-Driven Urban Block Design in Dry and Hot Regions of China}, journal = {Sustainability}, volume = {11}, year = {2019}, month = {Jan-07-2019}, pages = {3683}, abstract = {

In areas with a dry and hot climate, factors such as strong solar radiation, high temperature, low humidity, dazzling light, and dust storms can tremendously reduce people{\textquoteright}s thermal comfort. Therefore, researchers are paying more attention to outdoor thermal comfort in urban environments as part of urban design. This study proposed an automatic workflow to optimize urban spatial forms with the aim of improvement of outdoor thermal comfort conditions, characterized by the universal thermal climate index (UTCI). A city with a dry and hot climate{\textemdash}Kashgar, China{\textemdash}is further selected as an actual case study of an urban block and Rhino \& Grasshopper is the platform used to conduct simulation and optimization process with the genetic algorithm. Results showed that in summer, the proposed method can reduce the averaged UTCI from 31.17 to 27.43 {\textdegree}C, a decrease of about 3.74 {\textdegree}C, and reduce mean radiation temperature (MRT) from 43.94 to 41.29 {\textdegree}C, a decrease of about 2.65 {\textdegree}C.

}, keywords = {dry and hot areas; outdoor thermal comfort; urban morphology; urban performance simulation; genetic algorithm-driven}, doi = {10.3390/su11133683}, url = {https://www.mdpi.com/2071-1050/11/13/3683https://www.mdpi.com/2071-1050/11/13/3683/pdf}, author = {Xu, Xiaodong and Yin, Chenhuan and Wang, Wei and Xu, Ning and Hong, Tianzhen and Li, Qi} } @article {31666, title = {The Squeaky wheel: Machine learning for anomaly detection in subjective thermal comfort votes}, journal = {Building and Environment}, volume = {151}, year = {2019}, month = {03/2019}, pages = {219 - 227}, abstract = {

Anomalous patterns in subjective votes can bias thermal comfort models built using data-driven approaches. A stochastic-based two-step framework to detect outliers in subjective thermal comfort data is proposed to address this problem. The anomaly detection technique involves defining similar conditions using a k-Nearest Neighbor (KNN) method and then quantifying the dissimilarity of the occupants{\textquoteright} votes from their peers under similar thermal conditions through a Multivariate Gaussian approach. This framework is used to detect outliers in the ASHRAE Global Thermal Comfort Database I \& II. The resulting anomaly-free dataset produced more robust comfort models avoiding dubious predictions. The proposed method has been proven to effectively distinguish outliers from inter-individual variabilities in thermal demand. The proposed anomaly detection framework could easily be applied to other applications with different variables or subjective metrics. Such a tool holds great promise for use in the development of occupancy responsive controls for automated building HVAC systems.

}, keywords = {anomaly detection, ASHRAE global thermal comfort database, K-nearest neighbors, Multivariate Gaussian, Occupancy responsive controls, Subjective votes, thermal comfort}, issn = {03601323}, doi = {10.1016/j.buildenv.2019.01.050}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0360132319300861}, author = {Zhe Wang and Thomas Parkinson and Peixian Li and Borong Lin and Tianzhen Hong} } @article {32158, title = {Validation of an inverse model of zone air heat balance}, journal = {Building and Environment}, volume = {161}, year = {2019}, month = {Jan-08-2019}, pages = {106232}, abstract = {

This paper presents the validation method and results of an inverse model of zone air heat balance. The inverse model, implemented in EnergyPlus and published in a previous article [1], calculates highly uncertain model parameters such as internal thermal mass and infiltration airflow by inversely solving the zone air heat balance equation using the easy-to-measure zone air temperature data. The paper provides technical details of validation from the experiments using LBNL{\textquoteright}s Facility for Low Energy eXperiment in Buildings (FLEXLAB) that measures zone air temperature under the controlled experiment of two levels of internal mass and four levels of infiltration airflow. The simulation results of the zone infiltration airflow and internal thermal mass from the inverse model agree well with the measured data from the FLEXLAB experiments. The validated inverse model in EnergyPlus can be used to enhance the energy modeling of existing buildings that enables energy performance assessments for energy efficiency improvements.

}, keywords = {Energy simulation, energyplus, infiltration, internal thermal mass, inverse model, sensor data}, issn = {03601323}, doi = {10.1016/j.buildenv.2019.106232}, author = {Lee, Sang Hoon and Hong, Tianzhen} } @article {30487, title = {Building Simulation: Ten Challenges}, journal = {Building Simulation}, volume = {11}, year = {2018}, abstract = {

Buildings consume more than one-third of the world{\textquoteright}s primary energy. Reducing energy use and greenhouse-gas emissions in the buildings sector through energy conservation and efficiency improvements constitutes a key strategy for achieving global energy and environmental goals. Building performance simulation has been increasingly used as a tool for designing, operating and retrofitting buildings to save energy and utility costs. However, opportunities remain for researchers, software developers, practitioners and policymakers to maximize the value of building performance simulation in the design and operation of low energy buildings and communities that leverage interdisciplinary approaches to integrate humans, buildings, and the power grid at a large scale. This paper presents ten challenges that highlight some of the most important issues in building performance simulation, covering the full building life cycle and a wide range of modeling scales. The formulation and discussion of each challenge aims to provide insights into the state-of-the-art and future research opportunities for each topic, and to inspire new questions from young researchers in this field.

}, keywords = {building energy use, building life cycle, building performance simulation, energy efficiency, energy modeling, zero-net-energy buildings}, doi = {10.1007/s12273-018-0444-x}, author = {Tianzhen Hong and Jared Langevin and Kaiyu Sun} } @article {31313, title = {Buildings.Occupants: a Modelica package for modelling occupant behaviour in buildings}, journal = {Journal of Building Performance Simulation}, year = {2018}, month = {11/2018}, pages = {1 - 12}, abstract = {

Energy-related occupant behaviour is crucial to design and operation of energy and control systems in buildings. Occupant behaviours are often oversimplified as static schedules or settings in building performance simulation ignoring their stochastic nature. The continuous and dynamic interaction between occupants and building systems motivates their simultaneous simulation in an efficient manner. In the past, simultaneous simulation has relied on co-simulation approaches or customized source code changes to building simulation programmes. This paper presents Buildings. Occupants, an open-source package implemented in Modelica, for the simulation of occupant behaviours of lighting, windows, blinds, heating and air conditioning systems in office and residential buildings. Examples were presented to illustrate how the models in the Occupants package are capable to simulate stochastic occupant behaviours. The major contribution of this work is to introduce the equation-based modelling approach to simulate occupant behaviours in buildings and to develop an open-source Occupants package in the Modelica language

}, keywords = {modelica, Modelica Buildings Library, Modelica Occupants Package, Occupant Behaviour, Occupant behaviour modelling}, issn = {1940-1493}, doi = {10.1080/19401493.2018.1543352}, url = {https://www.tandfonline.com/doi/full/10.1080/19401493.2018.1543352https://www.tandfonline.com/doi/pdf/10.1080/19401493.2018.1543352}, author = {Zhe Wang and Tianzhen Hong and Ruoxi Jia} } @article {31306, title = {Clustering and statistical analyses of air-conditioning intensity and use patterns in residential buildings}, journal = {Energy and Buildings}, volume = {174}, year = {2018}, month = {09/2018}, pages = {214 - 227}, abstract = {

Energy conservation in residential buildings has gained increased attention due to its large portion of global energy use and potential of energy savings. Occupant behavior has been recognized as a key factor influencing the energy use and load diversity in buildings, therefore more realistic and accurate air-conditioning (AC) operating schedules are imperative for load estimation in equipment design and operation optimization. With the development of sensor technology, it became easier to access an increasing amount of heating/cooling data from thermal energy metering systems in residential buildings, which provides another possible way to understand building energy usage and occupant behaviors. However, except for cooling energy consumption benchmarking, there currently lacks effective and easy approaches to analyze AC usage and provide actionable insights for occupants. To fill this gap, this study proposes clustering analysis to identify AC use patterns of residential buildings, and develops new key performance indicators (KPIs) and data analytics to explore the AC operation characteristics using the long-term metered cooling energy use data, which is of great importance for inhabitants to understand their thermal energy use and save energy cost through adjustment of their AC use behavior. We demonstrate the proposed approaches in a residential district comprising 300 apartments, located in Zhengzhou, China. Main outcomes include: Representative AC use patterns are developed for three room types of residential buildings in the cold climate zone of China, which can be used as more realistic AC schedules to improve accuracy of energy simulation; Distributions of KPIs on household cooling energy usage are established, which can be used for household AC use intensity benchmarking and performance diagnoses.

}, keywords = {AC usage benchmarking, Air-conditioning, Clustering analysis, KPIs, residential building, Use pattern}, issn = {03787788}, doi = {10.1016/j.enbuild.2018.06.035}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0378778818307199https://api.elsevier.com/content/article/PII:S0378778818307199?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0378778818307199?httpAccept=text/plain}, author = {Jingjing An and Da Yan and Tianzhen Hong} } @article {30490, title = {Comparative Study of Air-Conditioning Energy Use of Four Office Buildings in China and USA}, journal = {Energy and Buildings}, volume = {169}, year = {2018}, abstract = {

Energy use in buildings has great variability. In order to design and operate low energy buildings as well as to establish building energy codes and standards and effective energy policy, it is crucial to understand and quantify key factors influencing building energy performance. This study investigates air-conditioning (AC) energy use of four office buildings in four locations: Beijing, Taiwan, Hong Kong, and Berkeley. Building simulation was employed to quantify the influences of key factors, including climate, building envelope and occupant behavior. Through simulation of various combinations of the three influencing elements, it is found that climate can lead to AC cooling consumption differences by almost two times, while occupant behavior resulted in the greatest differences (of up to three times) in AC cooling consumption. The influence of occupant behavior on AC energy consumption is not homogeneous. Under similar climates, when the occupant behavior in the building differed, the optimized building envelope design also differed. Overall, the optimal building envelope should be determined according to the climate as well as the occupants who use the building.

}, keywords = {Building envelope, climate, energy consumption, occupant behavior, office buildings, technological choice}, doi = {10.1016/j.enbuild.2018.03.073}, author = {Xin Zhou and Da Yan and Jingjing An and Tianzhen Hong and Xing Shi and Xing Jin} } @conference {31743, title = {Control Description Language}, booktitle = {1st American Modelica Conference}, year = {2018}, month = {08/2018}, abstract = {

Properly designed and implemented building control sequences can significantly reduce energy consumption. However, there is currently no process with supporting tools that allows the assessment of the performance of different control sequences, export the control sequences in a vendor-neutral format for cost estimation and for implementation on a building automation system through machine-to-machine translation, and reuse the sequences for verification during commissioning.

This paper describes a Control Description Language (CDL) that we developed to create such a process. For CDL, we selected a subset of Modelica that allows a convenient representation of control sequences, simulation of the control sequence coupled to a building energy model, and development of translators from CDL to building automation systems. To aid in the development of such translators, we created a translator from CDL to a JSON intermediate format. In future work, we seek to work with building control providers to develop translators from CDL to commercial building automation systems.

Through a case study, we show that CDL suffices for simulation-based performance assessment of two ASHRAE-published control sequences for a variable air volume flow system of an office building. Moreover, the case study showed that merely due to differences in the control sequences, annual HVAC energy use was reduced by 30\%. This difference is larger than the accuracy required when comparing different HVAC systems, thereby questioning the current practice of idealizing control sequences in building energy simulations, and demonstrating the importance of ensuring that the control sequence used during design simulations corresponds to the control sequence that will be implemented in the real building

}, keywords = {buildings, controls, hvac}, url = {https://simulationresearch.lbl.gov/wetter/download/2018-americanModelica-WetterGrahovacHu.pdf}, author = {Michael Wetter and Milica Grahovac and Jianjun Hu} } @article {31307, title = {A critical review on questionnaire surveys in the field of energy-related occupant behaviour}, journal = {Energy Efficiency}, year = {2018}, month = {07/2018}, pages = {1-21}, abstract = {

Occupants perform various actions to satisfy their physical and non-physical needs in buildings. These actions greatly affect building operations and thus energy use. Clearly understanding and accurately modelling occupant behaviour in buildings are crucial to guide energy-efficient building design and operation, and to reduce the gap between design and actual energy performance of buildings. To study and understand occupant behaviour, a cross-sectional questionnaire survey is one of the most useful tools to gain insights on general behaviour patterns and drivers, and to find connections between human, social and local comfort parameters. In this study, 33 projects were reviewed from the energy-related occupant behaviour research literature that employed cross-sectional surveys or interviews for data collection from the perspective of findings, limitations and methodological challenges. This research shows that future surveys are needed to bridge the gaps in literature but they would need to encompass a multidisciplinary approach to do so as until now only environmental and engineering factors were considered in these studies. Insights from social practice theories and techniques must be acquired to deploy robust and unbiased questionnaire results, which will provide new, more comprehensive knowledge in the field, and therefore occupant behaviour could be better understood and represented in building performance simulation to support design and operation of low or net-zero energy buildings.

}, keywords = {behaviour modeling, energy efficiency, Energy use in buildings, occupant behavior, questionnaire survey}, issn = {1570-646X}, doi = {10.1007/s12053-018-9711-z}, url = {http://link.springer.com/10.1007/s12053-018-9711-zhttp://link.springer.com/content/pdf/10.1007/s12053-018-9711-z.pdfhttp://link.springer.com/content/pdf/10.1007/s12053-018-9711-z.pdfhttp://link.springer.com/article/10.1007/s12053-018-9711-z/fulltext.html}, author = {Zsofia Belafi and Tianzhen Hong and Andras Reith} } @article {31663, title = {A Framework for Privacy-Preserving Data Publishing with Enhanced Utility for Cyber-Physical Systems}, journal = {ACM Transactions on Sensor Networks}, volume = {14}, year = {2018}, month = {12/2018}, pages = {1 - 22}, abstract = {

Cyber-physical systems have enabled the collection of massive amounts of data in an unprecedented level of spatial and temporal granularity. Publishing these data can prosper big data research, which, in turn, helps improve overall system efficiency and resiliency. The main challenge in data publishing is to ensure the usefulness of published data while providing necessary privacy protection. In our previous work (Jia et al. 2017a), we presented a privacy-preserving data publishing framework (referred to as PAD hereinafter), which can guarantee k-anonymity while achieving better data utility than traditional anonymization techniques. PAD learns the information of interest to data users or features from their interactions with the data publishing system and then customizes data publishing processes to the intended use of data. However, our previous work is only applicable to the case where the desired features are linear in the original data record. In this article, we extend PAD to nonlinear features. Our experiments demonstrate that for various data-driven applications, PAD can achieve enhanced utility while remaining highly resilient to privacy threats.

}, keywords = {cyber physical systems, deep learning, k-anonymity, Privacy preservation, Smart buildings}, issn = {15504859}, doi = {10.1145/329407010.1145/3275520}, author = {Fisayo Caleb Sangogboye and Ruoxi Jia and Tianzhen Hong and Costas Spanos and Mikkel Baun Kj{\ae}rgaard} } @article {30484, title = {Human-building interaction at work: Findings from an interdisciplinary cross-country survey in Italy}, journal = {Building and Environment}, volume = {132}, year = {2018}, abstract = {

This study presents results from an interdisciplinary survey assessing contextual and behavioral factors driving occupants{\textquoteright} interaction with building and systems in offices located across three different Mediterranean climates in Turin (Northern), Perugia (Central), and Rende (Southern) Italy. The survey instrument is grounded in an interdisciplinary framework that bridges the gap between building physics and social science environments on the energy- and comfort-related human-building interaction in the workspace. Outcomes of the survey questionnaire provide insights into four key learning objectives: (1) individual occupant{\textquoteright}s motivational drivers regarding interaction with shared building environmental controls (such as adjustable thermostats, operable windows, blinds and shades, and artificial lighting), (2) group dynamics such as perceived social norms, attitudes, and intention to share controls, (3) occupant perception of the ease of use and knowledge of how to operate control systems, and (4) occupant-perceived comfort, satisfaction, and productivity. This study attempts to identify climatic, cultural, and socio-demographic influencing factors, as well as to establish the validity of the survey instrument and robustness of outcomes for future studies. Also, the paper aims at illustrating why and how social science insights can bring innovative knowledge into the adoption of building technologies in shared contexts, thus enhancing perceived environmental satisfaction and effectiveness of personal indoor climate control in office settings and impacting office workers{\textquoteright} productivity and reduced operational energy costs.

}, keywords = {Human-building interaction, indoor environmental comfort, interdisciplinary framework, occupant behavior, office buildings, questionnaire survey}, doi = {10.1016/j.buildenv.2018.01.039}, author = {Simona D{\textquoteright}Oca and Anna Laura Pisello and Marilena De Simone and Verena M. Barthelmes and Tianzhen Hong and Stefano P. Corgnati} } @article {31308, title = {Impact of post-rainfall evaporation from porous roof tiles on building cooling load in subtropical China}, journal = {Applied Thermal Engineering}, volume = {142}, year = {2018}, month = {09/2018}, pages = {391 - 400}, abstract = {

Rainfall occurs frequently in subtropical regions of China, with the subsequent water evaporation from building roofs impacting the thermal performance and the energy consumption of buildings. We proposed a novel simulation method using actual meteorological data to evaluate this impact. New features were developed in EnergyPlus to enable the simulation: (1) an evaporation latent heat flux source term was added to the heat balance equation of the external surface and (2) algorithms for the evaporative cooling module (ECM) were developed and implemented into EnergyPlus. The ECM experimental results showed good agreement with the simulated results. The ECM was used to assess the impact of evaporation from porous roof tiles on the cooling load of a one-floor building in subtropical China. The results show that the evaporation process decreased the maximal values of the external and internal roof surface temperatures by up to 6.4 {\textdegree}C and 3.2 {\textdegree}C, respectively, while the lower internal surface temperature decreased the room accumulated cooling load by up to 14.8\% during the hot summer period. The enhanced EnergyPlus capability can be used to evaluate the evaporative cooling performance of roofs with water-storage mediums, as well as to quantify their impact on building cooling loads.

}, keywords = {Building energy simulation, cooling load, energyplus, Evaporative Cooling, Rainfall event, Subtropical China}, issn = {13594311}, doi = {10.1016/j.applthermaleng.2018.07.033}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1359431117356107https://api.elsevier.com/content/article/PII:S1359431117356107?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S1359431117356107?httpAccept=text/plain}, author = {Lei Zhang and Rongpeng Zhang and Tianzhen Hong and Yu Zhang and Qinglin Meng} } @article {30485, title = {Impacts of Building Geometry Modeling Methods on the Simulation Results of Urban Building Energy Models}, journal = {Applied Energy}, volume = {215}, year = {2018}, abstract = {

Urban-scale building energy modeling (UBEM){\textemdash}using building modeling to understand how a group of buildings will perform together{\textemdash}is attracting increasing attention in the energy modeling field. Unlike modeling a single building, which will use detailed information, UBEM generally uses existing building stock data consisting of high-level building information. This study evaluated the impacts of three zoning methods and the use of floor multipliers on the simulated energy use of 940 office and retail buildings in three climate zones using City Building Energy Saver. The first zoning method, OneZone, creates one thermal zone per floor using the target building{\textquoteright}s footprint. The second zoning method, AutoZone, splits the building{\textquoteright}s footprint into perimeter and core zones. A novel, pixel-based automatic zoning algorithm is developed for the AutoZone method. The third zoning method, Prototype, uses the U.S. Department of Energy{\textquoteright}s reference building prototype shapes. Results show that simulated source energy use of buildings with the floor multiplier are marginally higher by up to 2.6\% than those modeling each floor explicitly, which take two to three times longer to run. Compared with the AutoZone method, the OneZone method results in decreased thermal loads and less equipment capacities: 15.2\% smaller fan capacity, 11.1\% smaller cooling capacity, 11.0\% smaller heating capacity, 16.9\% less heating loads, and 7.5\% less cooling loads. Source energy use differences range from -7.6\% to 5.1\%. When comparing the Prototype method with the AutoZone method, source energy use differences range from -12.1\% to 19.0\%, and larger ranges of differences are found for the thermal loads and equipment capacities. This study demonstrated that zoning methods have a significant impact on the simulated energy use of UBEM. One recommendation resulting from this study is to use the AutoZone method with floor multiplier to obtain accurate results while balancing the simulation run time for UBEM.

}, keywords = {CityBES, energyplus, Floor multiplier, Geometry Representation, Urban Building Energy Modeling, Zoning Method}, doi = {10.1016/j.apenergy.2018.02.073}, author = {Yixing Chen and Tianzhen Hong} } @article {30489, title = {A Library of Building Occupant Behaviour Models Represented in a Standardised Schema}, journal = {Energy Efficiency}, year = {2018}, abstract = {

Over the past four decades, a substantial body of literature has explored the impacts of occupant behaviour (OB) on building technologies, operation, and energy consumption. A large number of data-driven behavioural models have been developed based on field data. These models lack standardisation and consistency, leading to difficulties in applications and comparison. To address this problem, an ontology was developed using the drivers-needs-actions-systems (DNAS) framework. Recent work has been carried out to implement the theoretical DNAS framework into an eXtensible Markup Language (XML) schema, titled {\textquoteleft}occupant behaviour XML{\textquoteright} (obXML) which is a practical implementation of OB models that can be integrated into building performance simulation (BPS) programs. This paper presents a newly developed library of OB models represented in the standardised obXML schema format. This library provides ready-to-use examples for BPS users to employ more accurate occupant representation in their energy models. The library, which contains an initial effort of 52 OB models, was made publicly available for the BPS community. As part of the library development process, limitations of the obXML schema were identified and addressed, and future improvements were proposed. Authors hope that by compiling this library building, energy modellers from all over the world can enhance their BPS models by integrating more accurate and robust OB patterns.

}, keywords = {building performance simulation, obXML, Occupant Behaviour, occupant behaviour model, XML schema}, doi = {10.1007/s12053-018-9658-0}, author = {Zsofia Belafi and Tianzhen Hong and Andras Reith} } @article {30488, title = {Modeling occupancy distribution in large spaces with multi-feature classification algorithm}, journal = {Building and Environment}, volume = {137}, year = {2018}, abstract = {

Occupancy information enables robust and flexible control of heating, ventilation, and air-conditioning (HVAC) systems in buildings. In large spaces, multiple HVAC terminals are typically installed to provide cooperative services for different thermal zones, and the occupancy information determines the cooperation among terminals. However, a person count at room-level does not adequately optimize HVAC system operation due to the movement of occupants within the room that creates uneven load distribution. Without accurate knowledge of the occupants{\textquoteright} spatial distribution, the uneven distribution of occupants often results in under-cooling/heating or over-cooling/heating in some thermal zones. Therefore, the lack of high-resolution occupancy distribution is often perceived as a bottleneck for future improvements to HVAC operation efficiency. To fill this gap, this study proposes a multi-feature k-Nearest-Neighbors (k-NN) classification algorithm to extract occupancy distribution through reliable, low-cost Bluetooth Low Energy (BLE) networks. An on-site experiment was conducted in a typical office of an institutional building to demonstrate the proposed methods, and the experiment outcomes of three case studies were examined to validate detection accuracy. One method based on City Block Distance (CBD) was used to measure the distance between detected occupancy distribution and ground truth and assess the results of occupancy distribution. The results show the accuracy when CBD = 1 is over 71.4\% and the accuracy when CBD = 2 can reach up to 92.9\%.

}, keywords = {energy efficiency, HVAC loads, multi-feature classification algorithm, occupancy distribution, occupancy-based control}, doi = {10.1016/j.buildenv.2018.04.002}, author = {Wei Wang and Jiayu Chen and Tianzhen Hong} } @article {30486, title = {A Novel Variable Refrigerant Flow (VRF) Heat Recovery System Model: Development and Validation}, journal = {Energy and Buildings}, volume = {168}, year = {2018}, abstract = {

As one of the latest emerging HVAC technologies, the Variable Refrigerant Flow (VRF) system with heat recovery (HR) configurations has obtained extensive attention from both the academia and industry. Compared with the conventional VRF systems with heat pump (HP) configurations, VRF-HR is capable of recovering heat from cooling zones to heating zones and providing simultaneous cooling and heating operations. This can further lead to substantial energy saving potential and more flexible zonal control. In this paper, a novel model is developed to simulate the energy performance of VRF-HR systems. It adheres to a more physics-based development with the ability to simulate the refrigerant loop performance and consider the dynamics of more operational parameters, which is essential for representing more advanced control logics. Another key feature of the model is the introduction of component-level curves for indoor units and outdoor units instead of overall performance curves for the entire system, and thus it requires much fewer user-specified performance curves as model inputs. The validation study shows good agreements between the simulated energy use from the new VRF-HR model and the laboratory measurement data across all operational modes at sub-hourly time steps. The model has been adopted in the official release of the EnergyPlus simulation program since Version 8.6, which enables more accurate and robust assessments of VRF-HR systems to support their applications in energy retrofit of existing buildings or design of zero-net-energy buildings.

}, keywords = {building performance simulation, controls, energy modeling, heat recovery, validation, Variable refrigerant flow}, doi = {10.1016/j.enbuild.2018.03.028}, author = {Rongpeng Zhang and Kaiyu Sun and Tianzhen Hong and Yoshinori Yura and Ryohei Hinokuma} } @article {31309, title = {Occupancy prediction through machine learning and data fusion of environmental sensing and Wi-Fi sensing in buildings}, journal = {Automation in Construction}, volume = {94}, year = {2018}, month = {10/2018}, pages = {233 - 243}, abstract = {

Occupancy information is crucial to building facility design, operation, and energy efficiency. Many studies propose the use of environmental sensors (such as carbon dioxide, air temperature, and relative humidity sensors) and radio-frequency sensors (Wi-Fi networks) to monitor, assess, and predict occupancy information for buildings. As many methods have been developed and a variety of sensory data sources are available, establishing a proper selection of model and data source is critical to the successful implementation of occupancy prediction systems. This study compared three popular machine learning algorithms, including k-nearest neighbors (kNN), support vector machine (SVM), and artificial neural network (ANN), combined with three data sources, including environmental data, Wi-Fi data, and fused data, to optimize the occupancy models{\textquoteright} performance in various scenarios. Three error measurement metrics, the mean average error (MAE), mean average percentage error (MAPE), and root mean squared error (RMSE), have been employed to compare the models{\textquoteright} accuracies. Examined with an on-site experiment, the results suggest that the ANN-based model with fused data has the best performance, while the SVM model is more suitable with Wi-Fi data. The results also indicate that, comparing with independent data sources, the fused data set does not necessarily improve model accuracy but shows a better robustness for occupancy prediction.

}, keywords = {data fusion, environmental sensing, Machine learning, occupancy prediction, Wi-Fi sensing}, issn = {09265805}, doi = {10.1016/j.autcon.2018.07.007}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0926580518302656https://api.elsevier.com/content/article/PII:S0926580518302656?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0926580518302656?httpAccept=text/plain}, author = {Wei Wang and Jiayu Chen and Tianzhen Hong} } @article {31304, title = {Occupancy prediction through Markov based feedback recurrent neural network (M-FRNN) algorithm with WiFi probe technology}, journal = {Building and Environment}, volume = {138}, year = {2018}, month = {06/2018}, pages = {160 - 170}, abstract = {

Accurate occupancy prediction can improve facility control and energy efficiency of buildings. In recent years, buildings{\textquoteright} exiting WiFi infrastructures have been widely studied in the research of occupancy and energy conservation. However, using WiFi to assess occupancy is challenging due to that occupancy information is often characterized stochastically and varies with time and easily disturbed by building components. To overcome such limitations, this study utilizes WiFi probe technology to actively scan WiFi connection requests and responses between access points and network devices of building occupants. With captured signals, this study proposed a Markov based feedback recurrent neural network (M-FRNN) algorithm to model and predict the occupancy profiles. One on-site experiment was conducted to collect ground truth data using camera-based video analysis and the results were used to validate the M-FRNN occupancy prediction model over a 9-day measurement period. From the results, the M-FRNN based occupancy model using WiFi probes shows best accuracies can reach 80.9\%, 89.6\%, and 93.9\% with a tolerance of 2, 3, and 4 occupants respectively. This study demonstrated that WiFi data coupled with stochastic machine learning system can provide a viable alternative to determine a building{\textquoteright}s occupancy profile.

}, issn = {03601323}, doi = {10.1016/j.buildenv.2018.04.034}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0360132318302464https://api.elsevier.com/content/article/PII:S0360132318302464?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0360132318302464?httpAccept=text/plain}, author = {Wei Wang and Jiayu Chen and Tianzhen Hong and Na Zhu} } @conference {31688, title = {OpenBuildingControl: Modeling Feedback Control as a Step Towards Formal Design, Specification, Deployment and Verification of Building Control Sequences}, booktitle = {2018 Building Performance Modeling Conference and SimBuild co-organized by ASHRAE and IBPSA-USA}, year = {2018}, month = {09/2018}, address = {Chicago, IL}, abstract = {

This paper presents ongoing work to develop tools and a process that will allow building designers to instantiate control sequences, configure them for their project, assess their performance in closed loop building energy simulation, and then export these sequences (i) for the control provider to bid on the project and to implement the sequences through machine-to-machine translation, and (ii) for the commissioning agent to verify their correct implementation.

The paper reports on the following: (i) The specification of a Control Description Language, (ii) its use to implement a subset of the ASHRAE Guideline 36 sequences, released as part of the Modelica Buildings library, (iii) its use in annual closed-loop simulations of a variable air- volume flow system, and (iv) lessons learned regarding simulation of closed-loop control.

In our case study, the Guideline 36 sequences yield 30\% lower annual site HYAC energy use, under comparable comfort, than sequences published earlier by ASHRAE. The 30\% differences in annual HYAC energy consumption due to changes in the control sequences raises the question of whether the idealization of control sequences that is common practice in today{\textquoteright}s building energy simulation leads to trustworthy energy use predictions.

}, url = {https://www.ashrae.org/File\%20Library/Conferences/Specialty\%20Conferences/2018\%20Building\%20Performance\%20Analysis\%20Conference\%20and\%20SimBuild/Papers/C107.pdf}, author = {Michael Wetter and Jianjun Hu and Milica Grahovac and Brent Eubanks and Philip Haves} } @article {31311, title = {Performance-Based Evaluation of Courtyard Design in China{\textquoteright}s Cold-Winter Hot-Summer Climate Regions}, journal = {Sustainability}, volume = {10}, year = {2018}, month = {10/2018}, pages = {3950}, abstract = {

Evaluates the performance of the traditional courtyard design of the Jiangnan Museum, located in Jiangsu Province. In the evaluation, the spatial layout of courtyards is adjusted, the aspect ratio is changed, and an ecological buffer space is created. To model and evaluate the performance of the courtyard design, this study applied the Computational fluid dynamics (CFD) software, Parabolic Hyperbolic Or Elliptic Numerical Integration Code Series (PHOENICS), for wind environment simulation, and the EnergyPlus-based software, DesignBuilder, for energy simulation. Results show that a good combination of courtyard layout and aspect ratio can improve the use of natural ventilation by increasing free cooling during hot summers and reducing cold wind in winters. The results also show that ecological buffer areas of a courtyard can reduce cooling loads in summer by approximately 19.6\% and heating loads in winter by approximately 22.3\%. The study provides insights into the optimal design of a courtyard to maximize its benefit in regulating the microclimate during both winter and summer.

}, keywords = {aspect ratio, courtyard design, ecological buffer area, ecological effect, layout}, doi = {10.3390/su10113950}, url = {http://www.mdpi.com/2071-1050/10/11/3950http://www.mdpi.com/2071-1050/10/11/3950/pdf}, author = {Xiaodong Xu and Fenlan Luo and Wei Wang and Tianzhen Hong and Xiuzhang Fu} } @article {30483, title = {Quantifying the benefits of a building retrofit using an integrated system approach: A case study}, journal = {Energy and Buildings}, volume = {159}, year = {2018}, abstract = {

Building retrofits provide a large opportunity to significantly reduce energy consumption in the buildings sector. Traditional building retrofits focus on equipment upgrades, often at the end of equipment life or failure, and result in replacement with marginally improved similar technology and limited energy savings. The Integrated System (IS) retrofit approach enables much greater energy savings by leveraging interactive effects between end use systems, enabling downsized or lower energy technologies. This paper presents a case study in Hawaii quantifying the benefits of an IS retrofit approach compared to two traditional retrofit approaches: a Standard Practice of upgrading equipment to meet minimum code requirements, and an Improved Practice of upgrading equipment to a higher efficiency. The IS approach showed an energy savings of 84\% over existing building energy use, much higher than the traditional approaches of 13\% and 33\%. The IS retrofit also demonstrated the greatest energy cost savings potential. While the degree of savings realized from the IS approach will vary by building and climate, these findings indicate that savings on the order of 50\% and greater are not possible without an IS approach. It is therefore recommended that the IS approach be universally adopted to achieve deep energy savings.

}, keywords = {Building retrofit, building simulation, Energy conservation measures, energy savings, integrated design, integrated system}, doi = {10.1016/j.enbuild.2017.10.090}, author = {Cynthia Regnier and Kaiyu Sun and Tianzhen Hong and Mary Ann Piette} } @article {31310, title = {Representation and evolution of urban weather boundary conditions in downtown Chicago}, journal = {Journal of Building Performance Simulation}, year = {2018}, month = {11/2018}, pages = {1 - 14}, abstract = {

This study presents a novel computing technique for data exchange and coupling between a high-resolution weather simulation model and a building energy model, with a goal of evaluating the impact of urban weather boundary conditions on energy performance of urban buildings. The Weather Research and Forecasting (WRF) model is initialized with the operational High-Resolution Rapid Refresh (HRRR) dataset to provide hourly weather conditions over the Chicago region. We utilize the building footprint, land use, and building stock datasets to generate building energy models using EnergyPlus. We mapped the building exterior surfaces to local air nodes to import simulated microclimate data and to export buildings{\textquoteright} heat emissions to their local environment. Preliminary experiments for a test area in Chicago show that predicted building cooling energy use differs by about 4.7\% for the selected date when compared with simulations using TMY weather data and without considering the urban microclimate boundary conditions.

}, keywords = {coupling, energy modeling, energyplus, Urban climate modeling, WRF}, issn = {1940-1493}, doi = {10.1080/19401493.2018.1534275}, url = {https://www.tandfonline.com/doi/full/10.1080/19401493.2018.1534275https://www.tandfonline.com/doi/pdf/10.1080/19401493.2018.1534275}, author = {Rajeev Jain and Xuan Luo and G{\"o}khan Sever and Tianzhen Hong and Charlie Catlett} } @article {30726, title = {Simplifications for hydronic system models in Modelica}, journal = {Journal of Building Performance Simulation}, year = {2018}, abstract = {

Building systems and their heating, ventilation and air conditioning ow networks, are becoming increasingly complex. Some building energy simulation tools simulate these ow networks using pressure drop equations. These ow network models typically generate coupled algebraic nonlinear systems of equations, which become increasingly more difficult to solve as their sizes increase. This leads to longer computation times and can cause the solver to fail. These problems also arise when using the equation-based modelling language Modelica and Annex 60 based libraries. This may limit the applicability of the library to relatively small problems unless problems are restructured. This paper discusses two algebraic loop types and presents an approach that decouples algebraic loops into smaller parts, or removes them completely. The approach is applied to a case study model where an algebraic loop of 86 iteration variables is decoupled into smaller parts with a maximum of 5 iteration variables.

}, doi = {10.1080/19401493.2017.1421263}, author = {Filip Jorissen and Michael Wetter and Lieve Helsen} } @article {31305, title = {Translating climate change and heating system electrification impacts on building energy use to future greenhouse gas emissions and electric grid capacity requirements in California}, journal = {Applied Energy}, volume = {225}, year = {2018}, month = {09/2018}, pages = {522 - 534}, abstract = {

Climate change and increased electrification of space and water heating in buildings can significantly affect future electricity demand and hourly demand profiles, which has implications for electric grid greenhouse gas emissions and capacity requirements. We use EnergyPlus to quantify building energy demand under historical and under several climate change projections of 32 kinds of building prototypes in 16 different climate zones of California and imposed these impacts on a year 2050 electric grid configuration by simulation in the Holistic Grid Resource Integration and Deployment (HIGRID) model. We find that climate change only prompted modest increases in grid resource capacity and negligible difference in greenhouse gas emissions since the additional electric load generally occurred during times with available renewable generation. Heating electrification, however, prompted a 30{\textendash}40\% reduction in greenhouse gas emissions but required significant grid resource capacity increases, due to the higher magnitude of load increases and lack of readily available renewable generation during the times when electrified heating loads occurred. Overall, this study translates climate change and electrification impacts to system-wide endpoint impacts on future electric grid configurations and highlights the complexities associated with translating building-level impacts to electric system-wide impacts.

}, keywords = {Building Energy Demand, Climate Change Impacts, electric grid, Heating Electrification Effects}, issn = {03062619}, doi = {10.1016/j.apenergy.2018.05.003}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0306261918306962https://api.elsevier.com/content/article/PII:S0306261918306962?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0306261918306962?httpAccept=text/plain}, author = {Brian Tarroja and Felicia Chiang and Amir AghaKouchak and Scott Samuelsen and Shuba V. Raghavan and Max Wei and Kaiyu Sun and Tianzhen Hong} } @article {29894, title = {An Agent-Based Stochastic Occupancy Simulator}, year = {2017}, abstract = {

Occupancy has significant impacts on building performance. However, in current building performance simulation programs, occupancy inputs are static and lack diversity, contributing to discrepancies between the simulated and actual building performance. This paper presents an Occupancy Simulator that simulates the stochastic behavior of occupant presence and movement in buildings, capturing the spatial and temporal occupancy diversity. Each occupant and each space in the building are explicitly simulated as an agent with their profiles of stochastic behaviors. The occupancy behaviors are represented with three types of models: (1) the status transition events (e.g., first arrival in office) simulated with Reinhart{\textquoteright}s LIGHTSWITCH-2002 model, (2) the random moving events (e.g., from one office to another) simulated with Wang{\textquoteright}s homogeneous Markov chain model, and (3) the meeting events simulated with a new stochastic model. A hierarchical data model was developed for the Occupancy Simulator, which reduces the amount of data input by using the concepts of occupant types and space types. Finally, a case study of a small office building is presented to demonstrate the use of the Simulator to generate detailed annual sub-hourly occupant schedules for individual spaces and the whole building. The Simulator is a web application freely available to the public and capable of performing a detailed stochastic simulation of occupant presence and movement in buildings. Future work includes enhancements in the meeting event model, consideration of personal absent days, verification and validation of the simulated occupancy results, and expansion for use with residential buildings.

}, author = {Yixing Chen and Tianzhen Hong and Xuan Luo} } @article {30314, title = {Analysis of heating load diversity in German residential districts and implications for the application in district heating systems}, journal = {Energy and Buildings}, volume = {139}, year = {2017}, month = {01/2017}, pages = {302-313}, chapter = {302}, abstract = {

In recent years, the application of district heating systems for the heat supply of residential districts has been increasing in Germany. Central supply systems can be very efficient due to diverse energy demand profiles which may lead to reduced installed equipment capacity. Load diversity in buildings has been investigated in former studies, especially for the electricity demand. However, little is known about the influence of single building characteristics (such as building envelope or hot water demand) on the overall heating peak load of a residential district. For measuring the diversity, the peak load ratio (PLR) index is used to represent the percentage reduction of peak load of a district system from a simple sum of individual peak loads of buildings. A total of 144 residential building load profiles have been created with the dynamic building simulation software IDA ICE for a theoretical analysis in which the PLR reaches 15\%. Within this study, certain district features are identified which lead to higher diversity. Furthermore, these results are used in a district heating simulation model which confronts the possible advantage of reduced installed capacity with the practical disadvantage of heat distribution losses.\  Likewise, the influence of load density and the district{\textasciiacute}s building structure can be analyzed. This study shows that especially in districts with high load density, which consist of newly constructed buildings with low supply temperature and high influence of the hot water demand, the advantages of load diversity can be exploited.

}, keywords = {district heating, domestic hot water, dynamic building simulation, heat supply, Load diversity, peak load, residential district, space heating}, doi = {10.1016/j.enbuild.2016.12.096}, author = {Claudia Weissmann and Tianzhen Hong and Carl-Alexander Graubner} } @article {30026, title = {Automatic Generation and Simulation of Urban Building Energy Models Based on City Datasets for City-Scale Building Retrofit Analysis}, year = {2017}, abstract = {

Buildings in cities consume 30\% to 70\% of total primary energy, and improving building energy efficiency is one of the key strategies towards sustainable urbanization. Urban building energy models (UBEM) can support city managers to evaluate and prioritize energy conservation measures (ECMs) for investment and the design of incentive and rebate programs. This paper presents the retrofit analysis feature of City Building Energy Saver (CityBES) to automatically generate and simulate UBEM using EnergyPlus based on cities{\textquoteright} building datasets and user-selected ECMs. CityBES is a new open web-based tool to support city-scale building energy efficiency strategic plans and programs. The technical details of using CityBES for UBEM generation and simulation are introduced, including the workflow, key assumptions, and major databases. Also presented is a case study that analyzes the potential retrofit energy use and energy cost savings of five individual ECMs and two measure packages for 940 office and retail buildings in six city districts in northeast San Francisco, United States. The results show that: (1) all five measures together can save 23\%-38\% of site energy per building; (2) replacing lighting with light-emitting diode lamps and adding air economizers to existing heating, ventilation and air-conditioning (HVAC) systems are most cost-effective with an average payback of 2.0 and 4.3 years, respectively; and (3) it is not economical to upgrade HVAC systems or replace windows in San Franciso due to the city{\textquoteright}s mild climate and minimal cooling and heating loads. The CityBES retrofit analysis feature does not require users to have deep knowledge of building systems or technologies for the generation and simulation of building energy models, which helps overcome major technical barriers for city managers and their consultants to adopt UBEM.

}, keywords = {Building Energy Modeling, CityBES, Energy conservation measures, energyplus, Retrofit Analysis, Urban Scale}, author = {Yixing Chen and Tianzhen Hong and Mary Ann Piette} } @article {30301, title = {Comparison of typical year and multiyear building simulations using a 55-year actual weather data set from China}, journal = {Applied Energy}, volume = {195}, year = {2017}, month = {06/2017}, pages = {890-904}, abstract = {

Weather has significant impacts on the thermal environment and energy use in buildings. Thus, accurate weather data are crucial for building performance evaluations. Traditionally, typical year data inputs are used to represent long-term weather data. However, there is no guarantee that a single year represents the changing climate well. In this study, the long-term representation of a typical year was assessed by comparing it to a 55-year actual weather data set. To investigate the weather impact on building energy use, 559 simulation runs of a prototype office building were performed for 10 large cities covering all climate zones in China. The analysis results demonstrated that the weather data varied significantly from year to year. Hence, a typical year cannot reflect the variation range of weather fluctuations. Typical year simulations overestimated or underestimated the energy use and peak load in many cases. With the increase in computational power of personal computers, it is feasible and essential to adopt multiyear simulations for full assessments of long-term building performance, as this will improve decision-making by allowing for the full consideration of variations in building energy use.

}, keywords = {Actual weather data, building simulation, energy use, Multiyear simulation, Peak load , Typical year}, doi = {10.1016/j.apenergy.2017.03.113}, author = {Ying Cui and Da Yan and Tianzhen Hong and Chan Xiao and Xuan Luo and Qi Zhang} } @article {30028, title = {Data Analytics and Optimization of an Ice-Based Energy Storage System for Commercial Buildings}, year = {2017}, abstract = {

Ice-based thermal energy storage (TES) systems can shift peak cooling demand and reduce operational energy costs (with time-of-use rates) in commercial buildings. The accurate prediction of the cooling load, and the optimal control strategy for managing the charging and discharging of a TES system, are two critical elements to improving system performance and achieving energy cost savings. This study utilizes data-driven analytics and modeling to holistically understand the operation of an ice{\textendash}based TES system in a shopping mall, calculating the system{\textquoteright}s performance using actual measured data from installed meters and sensors. Results show that there is significant savings potential when the current operating strategy is improved by appropriately scheduling the operation of each piece of equipment of the TES system, as well as by determining the amount of charging and discharging for each day. A novel optimal control strategy, determined by an optimization algorithm of Sequential Quadratic Programming, was developed to minimize the TES system{\textquoteright}s operating costs. Three heuristic strategies were also investigated for comparison with our proposed strategy, and the results demonstrate the superiority of our method to the heuristic strategies in terms of total energy cost savings. Specifically, the optimal strategy yields energy costs of up to 11.3\% per day and 9.3\% per month compared with current operational strategies. A one-day-ahead hourly load prediction was also developed using machine learning algorithms, which facilitates the adoption of the developed data analytics and optimization of the control strategy in a real TES system operation.

}, keywords = {Data Analytics, energy cost saving, heuristic strategy, Machine learning, optimization, Thermal energy storage}, author = {Na Luo and Tianzhen Hong and Hui Li and Rouxi Jia and Wenguo Weng} } @conference {29803, title = {Development of Automated Procedures to Generate Reference Building Models for ASHRAE Standard 90.1 and India{\textquoteright}s Building Energy Code and Implementation in OpenStudio}, booktitle = {Building Simulation 2017}, year = {2017}, month = {08/2017}, address = {San Francisco, CA}, abstract = {

This paper describes a software system for automatically generating a reference (baseline) building energy model from the proposed (as-designed) building energy model. This system is built using the OpenStudio Software Development Kit (SDK) and is designed to operate on building energy models in the OpenStudio file format.\ 

}, author = {Andrew Parker and Philip Haves and Subhash Jegi and Vishal Garg and Baptiste Ravache} } @article {30728, title = {Dynamic equation-based thermo-hydraulic pipe model for district heating and cooling systems}, journal = {Energy Conversion and Management}, volume = {151}, year = {2017}, abstract = {

Simulation and optimisation of district heating and cooling networks requires efficient and realistic models of the individual network elements in order to correctly represent heat losses or gains, temperature propagation and pressure drops. Due to more recent thermal networks incorporating meshing decentralised heat and cold sources, the system often has to deal with variable temperatures and mass flow rates, with flow reversal occurring more frequently. This paper presents the mathematical derivation and software implementation in Modelica of a thermo-hydraulic model for thermal networks that meets the above requirements and compares it to both experimental data and a commonly used model. Good correspondence between experimental data from a controlled test set-up and simulations using the presented model was found. Compared to measurement data from a real district heating network, the simulation results led to a larger error than in the controlled test set-up, but the general trend is still approximated closely and the model yields results similar to a pipe model from the Modelica Standard Library. However, the presented model simulates 1.7 (for low number of volumes) to 68 (for highly discretized pipes) times faster than a conventional model for a realistic test case. A working implementation of the presented model is made openly available within the IBPSA Modelica Library. The model is robust in the sense that grid size and time step do not need to be adapted to the flow rate, as is the case in finite volume models.

}, doi = {10.1016/j.enconman.2017.08.072}, author = {Brahm van der Heijde and Marcus Fuchs and Carles Ribas Tugores and Gerald Schweiger and Kevin Sartor and Daniele Basciotti and Dirk Muller and Christoph Nytsch-Geusen and Michael Wetter and Lieve Helsen} } @article {30027, title = {Electric Load Shape Benchmarking for Small- and Medium-Sized Commercial Buildings}, year = {2017}, abstract = {

Small- and medium-sized commercial buildings owners and utility managers often look for opportunities for energy cost savings through energy efficiency and energy waste minimization. However, they currently lack easy access to low-cost tools that help interpret the massive amount of data needed to improve understanding of their energy use behaviors. Benchmarking is one of the techniques used in energy audits to identify which buildings are priorities for an energy analysis. Traditional energy performance indicators, such as the energy use intensity (annual energy per unit of floor area), consider only the total annual energy consumption, lacking consideration of the fluctuation of energy use behavior over time, which reveals the time of use information and represents distinct energy use behaviors during different time spans. To fill the gap, this study developed a general statistical method using 24-hour electric load shape benchmarking to compare a building or business/tenant space against peers. Specifically, the study developed new forms of benchmarking metrics and data analysis methods to infer the energy performance of a building based on its load shape. We first performed a data experiment with collected smart meter data using over 2,000 small- and medium-sized businesses in California. We then conducted a cluster analysis of the source data, and determined and interpreted the load shape features and parameters with peer group analysis. Finally, we implemented the load shape benchmarking feature in an open-access web-based toolkit (the Commercial Building Energy Saver) to provide straightforward and practical recommendations to users. The analysis techniques were generic and flexible for future datasets of other building types and in other utility territories.

}, keywords = {benchmarking, Building energy, cluster analysis, load profile, load shape, representative load pattern}, author = {Xuan Luo and Tianzhen Hong and Yixing Chen and Mary Ann Piette} } @article {62077, title = {Energy saving potential of a two-pipe system for simultaneous heating and cooling of office buildings}, journal = {Energy and Buildings}, volume = {134}, year = {2017}, month = {01/2017}, pages = {234 - 247}, abstract = {

This paper analyzes the performance of a novel two-pipe system that operates one water loop to simultaneously provide space heating and cooling with a water supply temperature of around 22 {\textdegree}C. To analyze the energy performance of the system, a simulation-based research was conducted. The two-pipe system was modelled using the equation-based Modelica modeling language in Dymola. A typical office building model was considered as the case study. Simulations were run for two construction sets of the building envelope and two conditions related to inter-zone air flows. To calculate energy savings, a conventional four-pipe system was modelled and used for comparison. The conventional system presented two separated water loops for heating and cooling with supply temperatures of 45 {\textdegree}C and 14 {\textdegree}C, respectively. Simulation results showed that the two-pipe system was able to use less energy than the four-pipe system thanks to three effects: useful heat transfer from warm to cold zones, higher free cooling potential and higher efficiency of the heat pump. In particular, the two-pipe system used approximately between 12\% and 18\% less total annual primary energy than the four-pipe system, depending on the simulation case considered.

}, keywords = {active beams, energy saving, HVAC systems, low-exergy, modelica, simulation}, issn = {03787788}, doi = {10.1016/j.enbuild.2016.10.051}, author = {Alessandro Maccarini and Michael Wetter and Alireza Afshari and Goran Hultmark and Niels Bergsoe and Anders Vorre} } @article {29895, title = {A Framework for Quantifying the Impact of Occupant Behavior on Energy Savings of Energy Conservation Measures}, year = {2017}, abstract = {

To improve energy efficiency{\textemdash}during new buildings design or during a building retrofit{\textemdash}evaluating the energy savings potential of energy conservation measures (ECMs) is a critical task. In building retrofits, occupant behavior significantly impacts building energy use and is a leading factor in uncertainty when determining the effectiveness of retrofit ECMs. Current simulation-based assessment methods simplify the representation of occupant behavior by using a standard or representative set of static and homogeneous assumptions ignoring the dynamics, stochastics, and diversity of occupant{\textquoteright}s energy-related behavior in buildings. The simplification contributes to significant gaps between the simulated and measured actual energy performance of buildings.

This study presents a framework for quantifying the impact of occupant behaviors on ECM energy savings using building performance simulation. During the first step of the study, three occupant behavior styles (austerity, normal, and wasteful) were defined to represent different levels of energy consciousness of occupants regarding their interactions with building energy systems (HVAC, windows, lights and plug-in equipment). Next, a simulation workflow was introduced to determine a range of the ECM energy savings. Then, guidance was provided to interpret the range of ECM savings to support ECM decision making. Finally, a pilot study was performed in a real building to demonstrate the application of the framework. Simulation results show that the impact of occupant behaviors on ECM savings vary with the type of ECM. Occupant behavior minimally affects energy savings for ECMs that are technology-driven (the relative savings differ by less than 2\%) and have little interaction with the occupants; for ECMs with strong occupant interaction, such as the use of zonal control variable refrigerant flow system and natural ventilation, energy savings are significantly affected by occupant behavior (the relative savings differ by up to 20\%). The study framework provides a novel, holistic approach to assessing the uncertainty of ECM energy savings related to occupant behavior, enabling stakeholders to understand and assess the risk of adopting energy efficiency technologies for new and existing buildings.

}, author = {Kaiyu Sun and Tianzhen Hong} } @article {29898, title = {The Human Dimensions of Energy Use in Buildings: A Review}, year = {2017}, abstract = {

The "human dimensions" of energy use in buildings refer to the energy-related behaviors of key stakeholders that affect energy use over the building life cycle. Stakeholders include building designers, operators, managers, engineers, occupants, industry, vendors, and policymakers, who directly or indirectly influence the acts of designing, constructing, living, operating, managing, and regulating the built environments, from individual building up to the urban scale. Among factors driving high-performance buildings, human dimensions play a role that is as significant as that of technological advances. However, this factor is not well understood, and, as a result, human dimensions are often ignored or simplified by stakeholders. This paper presents a review of the literature on human dimensions of building energy use to assess the state-of-the-art in this topic area. The paper highlights research needs for fully integrating human dimensions into the building design and operation processes with the goal of reducing energy use in buildings while enhancing occupant comfort and productivity. This research focuses on identifying key needs for each stakeholder involved in a building{\textquoteright}s lifecycle and takes an interdisciplinary focus that spans the fields of architecture and engineering design, sociology, data science, energy policy, codes, and standards to provide targeted insights. Greater understanding of the human dimensions of energy use has several potential benefits including reductions in operating cost for building owners;enhanced comfort conditions and productivity for building occupants;more effective building energy management and automation systems for building operators and energy managers; and the integration of more accurate control logic into the next generation of human-in-the-loop technologies. The review concludes by summarizing recommendations for policy makers and industry stakeholders for developing codes, standards, and technologies that can leverage the human dimensions of energy use to reliably predict and achieve energy use reductions in the residential and commercial buildings sectors.

}, author = {Simona D{\textquoteright}Oca and Tianzhen Hong and Jared Langevin} } @article {30481, title = {IEA EBC Annex 53: Total Energy Use in Buildings {\textendash} Analysis and Evaluation Methods}, journal = {Energy and Buildings}, volume = {152}, year = {2017}, abstract = {

One of the most significant barriers to achieving deep building energy efficiency is a lack of knowledge about the factors determining energy use. In fact, there is often a significant discrepancy between designed and real energy use in buildings, which is poorly understood but are believed to have more to do with the role of human behavior than building design. Building energy use is mainly influenced by six factors: climate, building envelope, building services and energy systems, building operation and maintenance, occupants{\textquoteright} activities and behavior, and indoor environmental quality. In the past, much research focused on the first three factors. However, the next three human-related factors can have an influence as significant as the first three. Annex 53 employed an interdisciplinary approach, integrating building science, architectural engineering, computer modeling and simulation, and social and behavioral science to develop and apply methods to analyze and evaluate the real energy use in buildings considering the six influencing factors. Outcomes from Annex 53 improved understanding and strengthen knowledge regarding the robust prediction of total energy use in buildings, enabling reliable quantitative assessment of energy-savings measures, policies, and techniques.

}, keywords = {energy data definition, energy modeling, energy monitoring, occupant behavior, Performance Evaluation, real energy use}, doi = {10.1016/j.enbuild.2017.07.038}, author = {Hiroshi Yoshino and Tianzhen Hong and Natasa Nord} } @article {30482, title = {IEA EBC Annex 66: Definition and simulation of occupant behavior in buildings}, journal = {Energy and Building}, volume = {156}, year = {2017}, abstract = {

More than 30\% of the total primary energy in the world is consumed in buildings. It is crucial to reduce building energy consumption in order to preserve energy resources and mitigate global climate change. Building performance simulations have been widely used for the estimation and optimization of building performance, providing reference values for the assessment of building energy consumption and the effects of energy-saving technologies. Among the various factors influencing building energy consumption, occupant behavior has drawn increasing attention. Occupant behavior includes occupant presence, movement, and interaction with building energy devices and systems. However, there are gaps in occupant behavior modeling as different energy modelers have employed varied data and tools to simulate occupant behavior, therefore producing different and incomparable results. Aiming to address these gaps, the International Energy Agency (IEA) Energy in Buildings and Community (EBC) Programme Annex 66 has established a scientific methodological framework for occupant behavior research, including data collection, behavior model representation, modeling and evaluation approaches, and the integration of behavior modeling tools with building performance simulation programs. Annex 66 also includes case studies and application guidelines to assist in building design, operation, and policymaking, using interdisciplinary approaches to reduce energy use in buildings and improve occupant comfort and productivity. This paper highlights the key research issues, methods, and outcomes pertaining to Annex 66, and offers perspectives on future research needs to integrate occupant behavior with the building life cycle.

}, keywords = {building performance, energy modeling, energy use, IEA EBC Annex 66, Interdisciplinary approach, occupant behavior}, doi = {10.1016/j.enbuild.2017.09.084}, author = {Da Yan and Tianzhen Hong and Bing Dong and Ardeshir Mahdavi and Simona D{\textquoteright}Oca and Isabella Gaetani and Xiaohang Feng} } @article {30031, title = {Modeling of HVAC Operational Faults in Building Performance Simulation}, year = {2017}, abstract = {

Operational faults are common in the heating, ventilating, and air conditioning (HVAC) systems of existing buildings, leading to a decrease in energy efficiency and occupant comfort. Various fault detection and diagnostic methods have been developed to identify and analyze HVAC operational faults at the component or subsystem level. However, current methods lack a holistic approach to predicting the overall impacts of faults at the building level{\textemdash}an approach that adequately addresses the coupling between various operational components, the synchronized effect between simultaneous faults, and the dynamic nature of fault severity. This study introduces the novel development of a fault-modeling feature in EnergyPlus which fills in the knowledge gap left by previous studies. This paper presents the design and implementation of the new feature in EnergyPlus and discusses in detail the fault-modeling challenges faced. The new fault-modeling feature enables EnergyPlus to quantify the impacts of faults on building energy use and occupant comfort, thus supporting the decision making of timely fault corrections. Including actual building operational faults in energy models also improves the accuracy of the baseline model, which is critical in the measurement and verification of retrofit or commissioning projects. As an example, EnergyPlus version 8.6 was used to investigate the impacts of a number of typical operational faults in an office building across several U.S. climate zones. The results demonstrate that the faults have significant impacts on building energy performance as well as on occupant thermal comfort. Finally, the paper introduces future development plans for EnergyPlus fault-modeling capability.

}, keywords = {energy performance, energyplus, hvac system, Modeling and simulation, Operational fault, Thermal comfort }, author = {Rongpeng Zhang and Tianzhen Hong} } @article {29897, title = {A Novel Stochastic Modeling Method to Simulate Cooling Loads in Residential Districts}, year = {2017}, abstract = {

District cooling systems are widely used in urban residential communities in China. Most district cooling systems are oversized;this leads to wasted investment and low operational efficiency and thus energy wastage. The accurate prediction of district cooling loads that supports rightsizing cooling plant equipment remains a challenge. This study developed a new stochastic modeling method that includes (1) six prototype house models representing a majority of apartments in the district, (2)occupant behavior models in residential buildings reflecting the temporal and spatial diversity and complexity based on a large-scale residential survey in China, and (3) a stochastic sampling process to represent all apartments and occupants in the district. The stochastic method was employed in a case study using the DeST simulation engine to simulate the cooling loads of a real residential district in Wuhan, China. The simulation results agree well with the actual measurement data based on five performance metrics representing the aggregated cooling loads, the peak cooling loads as well as the spatial load distribution,and the load profiles. Two currently used simulation methods were also employed to simulate the district cooling loads. The simulation results showed that oversimplified occupant behavior assumptions lead to significant overestimations of the peak cooling load and total district cooling loads. Future work will aim to simplify the workflow and data requirements of the stochastic method to enable its practical application as well as explore its application in predicting district heating loads and in commercial or mixed-use districts.

}, author = {Jingjing An and Da Yan and Tianzhen Hong and Kaiyu Sun} } @article {30029, title = {Occupant behavior models: A critical review of implementation and representation approaches in building performance simulation programs}, year = {2017}, abstract = {

Occupant behavior (OB) in buildings is a leading factor influencing energy use in buildings. Quantifying this influence requires the integration of OB models with building performance simulation (BPS). This study reviews approaches to representing and implementing OB models in today{\textquoteright}s popular BPS programs, and discusses weaknesses and strengths of these approaches and key issues in integrating of OB models with BPS programs. Two key findings are: (1) a common data model is needed to standardize the representation of OB models, enabling their flexibility and exchange among BPS programs and user applications; the data model can be implemented using a standard syntax (e.g., in the form of XML schema), and (2) a modular software implementation of OB models, such as functional mock-up units for co-simulation, adopting the common data model, has advantages in providing a robust and interoperable integration with multiple BPS programs. Such common OB model representation and implementation approaches help standardize the input structures of OB models, enable collaborative development of a shared library of OB models, and allow for rapid and widespread integration of OB models with BPS programs to improve the simulation of occupant behavior and quantification of their impact on building performance.

}, keywords = {Behavior Modeling, building performance simulation, co-simulation, data model, occupant behavior}, author = {Tianzhen Hong and Yixing Chen and Zsofia Belafi and Simona D{\textquoteright}Oca} } @article {30313, title = {Performance Evaluation of an Agent-based Occupancy Simulation Model}, journal = {Building and Environment}, volume = {115}, year = {2017}, month = {04/2017}, abstract = {

Occupancy is an important factor driving building performance. Static and homogeneous occupant schedules, commonly used in building performance simulation, contribute to issues such as performance gaps between simulated and measured energy use in buildings. Stochastic occupancy models have been recently developed and applied to better represent spatial and temporal diversity of occupants in buildings. However, there is very limited evaluation of the usability and accuracy of these models. This study used measured occupancy data from a real office building to evaluate the performance of an agent-based occupancy simulation model: the Occupancy Simulator. The occupancy patterns of various occupant types were first derived from the measured occupant schedule data using statistical analysis. Then the performance of the simulation model was evaluated and verified based on (1) whether the distribution of observed occupancy behavior patterns follows the theoretical ones included in the Occupancy Simulator, and (2) whether the simulator can reproduce a variety of occupancy patterns accurately. Results demonstrated the feasibility of applying the Occupancy Simulator to simulate a range of occupancy presence and movement behaviors for regular types of occupants in office buildings, and to generate stochastic occupant schedules at the room and individual occupant levels for building performance simulation. For future work, model validation is recommended, which includes collecting and using detailed interval occupancy data of all spaces in an office building to validate the simulated occupant schedules from the Occupancy Simulator.

}, keywords = {model performance evaluation, occupancy pattern, Occupancy simulation, occupant behavior, occupant presence and movement, verification}, doi = {10.1016/j.buildenv.2017.01.015}, author = {Xuan Luo and Khee Poh Lam and Yixing Chen and Tianzhen Hong} } @article {30030, title = {A Preliminary Investigation of Water Usage Behavior in Single-Family Homes}, year = {2017}, abstract = {

As regional drought conditions continue deteriorating around the world, residential water use has been brought into the built environment spotlight. Nevertheless, the understanding of water use behavior in residential buildings is still limited. This paper presents data analytics and results from monitoring data of daily water use (DWU) in 50 single-family homes in Texas, USA. The results show the typical frequency distribution curve of the DWU per household and indicate personal income, education level and energy use of appliances all have statistically significant effects on the DWU per capita. Analysis of the water-intensive use demonstrates the residents tend to use more water in post-vacation days. These results help generate awareness of water use behavior in homes. Ultimately, this research could support policy makers to establish a water use baseline and inform water conservation programs.

}, keywords = {daily water use, Data Analytics, occupant behavior, residential water consumption, Water usage behavior}, author = {Peng Xue and Tianzhen Hong and Bing Dong and Cheuk Ming Mak} } @article {30311, title = {Simulation and visualization of energy-related occupant behavior in office buildings}, journal = {Building Simulation}, volume = {10}, year = {2017}, month = {03/2017}, pages = {785{\textendash}798}, abstract = {

In current building performance simulation programs, occupant presence and interactions with building systems are over-simplified and less indicative of real world scenarios, contributing to the discrepancies between simulated and actual energy use in buildings. Simulation results are normally presented using various types of charts. However, using those charts, it is difficult to visualize and communicate the importance of occupants{\textquoteright} behavior to building energy performance. This study introduced a new approach to simulating and visualizing energy-related occupant behavior in office buildings. First, the Occupancy Simulator was used to simulate the occupant presence and movement and generate occupant schedules for each space as well as for each occupant. Then an occupant behavior functional mockup unit (obFMU) was used to model occupant behavior and analyze their impact on building energy use through co-simulation with EnergyPlus. Finally, an agent-based model built upon AnyLogic was applied to visualize the simulation results of the occupant movement and interactions with building systems, as well as the related energy performance. A case study using a small office building in Miami, FL was presented to demonstrate the process and application of the Occupancy Simulator, the obFMU and EnergyPlus, and the AnyLogic module in simulation and visualization of energy-related occupant behaviors in office buildings. The presented approach provides a new detailed and visual way for policy makers, architects, engineers and building operators to better understand occupant energy behavior and their impact on energy use in buildings, which can improve the design and operation of low energy buildings.

}, keywords = {Behavior Modeling, building performance, building simulation, energyplus, occupant behavior, visualization}, doi = {10.1007/s12273-017-0355-2}, author = {Yixing Chen and Xin Liang and Tianzhen Hong and Xuan Luo} } @article {29854, title = {Small and Medium Building Efficiency Toolkit and Community Demonstration Program}, year = {2017}, month = {03/2017}, abstract = {

Small commercial buildings in the United States consume 47 percent of all primary energy consumed in the building sector. Retrofitting small and medium commercial buildings may pose a steep challenge for owners, as many lack the expertise and resources to identify and evaluate cost-effective energy retrofit strategies. To address this problem, this project developed the Commercial Building Energy Saver (CBES), an energy retrofit analysis toolkit that calculates the energy use of a building, identifies and evaluates retrofit measures based on energy savings, energy cost savings, and payback. The CBES Toolkit includes a web app for end users and the CBES Application Programming Interface for integrating CBES with other energy software tools. The toolkit provides a rich feature set, including the following:

  1. Energy Benchmarking providing an Energy Star score
  2. Load Shape Analysis to identify potential building operation improvements
  3. Preliminary Retrofit Analysis which uses a custom developed pre-simulated database
  4. Detailed Retrofit Analysis which utilizes real time EnergyPlus simulations

In a parallel effort the project team developed technologies to measure outdoor airflow rate; commercialization and use would avoid both excess energy use from over ventilation and poor indoor air quality resulting from under ventilation.

If CBES is adopted by California{\textquoteright}s statewide small office and retail buildings, by 2030 the state can anticipate 1,587 gigawatt hours of electricity savings, 356 megawatts of non-coincident peak demand savings, 30.2 megatherms of natural gas savings, $227 million of energy-related cost savings, and reduction of emissions by 757,866 metric tons of carbon dioxide equivalent. In addition, consultant costs will be reduced in the retrofit analysis process.

CBES contributes to the energy savings retrofit field by enabling a straightforward and uncomplicated decision-making process for small and medium business owners and leveraging different levels of assessment to match user background, preference, and data availability.

}, keywords = {CBES, commercial buildings, energy efficiency, energy modeling, energy savings, indoor air quality, indoor environmental quality, outdoor air measurement technology, outdoor airflow intake rate, retrofit, ventilation rate}, doi = {10.7941/S93P70}, author = {Mary Ann Piette and Tianzhen Hong and William J. Fisk and Norman Bourassa and Wanyu R. Chan and Yixing Chen and H.Y. Iris Cheung and Toshifumi Hotchi and Margarita Kloss and Sang Hoon Lee and Phillip N. Price and Oren Schetrit and Kaiyu Sun and Sarah C. Taylor-Lange and Rongpeng Zhang} } @article {30305, title = {Smart Building Management vs. Intuitive Human Control {\textemdash} Lessons learnt from an office building in Hungary}, journal = {Building Simulation}, volume = {10}, year = {2017}, month = {12/2017}, pages = {811-828}, abstract = {

Smart building management and control are adopted nowadays to achieve zero-net energy use in buildings. However, without considering the human dimension, technologies alone do not necessarily guarantee high performance in buildings. An office building was designed and built according to state-of-the-art design and energy management principles in 2008. Despite the expectations of high performance, the owner was facing high utility bills and low user comfort in the building located in Budapest, Hungary. The objective of the project was to evaluate the energy performance and comfort indices of the building, to identify the causes of malfunction and to elaborate a comprehensive energy concept. Firstly, current building conditions and operation parameters were evaluated. Our investigation found that the state-of-the-art building management system was in good conditions but it was operated by building operators and occupants who are not aware of the building management practice. The energy consumption patterns of the building were simulated with energy modelling software. The baseline model was calibrated to annual measured energy consumption, using actual occupant behaviour and presence, based on results of self-reported surveys, occupancy sensors and fan-coil usage data. Realistic occupant behaviour models can capture diversity of occupant behaviour and better represent the real energy use of the building. This way our findings and the effect of our proposed improvements could be more reliable. As part of our final comprehensive energy concept, we proposed intervention measures that would increase indoor thermal comfort and decrease energy consumption of the building. A parametric study was carried out to evaluate and quantify energy, comfort and return on investment of each measure. It was found that in the best case the building could save 23\% of annual energy use. Future work includes the follow-up of: occupant reactions to intervention measures, the realized energy savings, the measurement of occupant satisfaction and behavioural changes.

}, keywords = {building operation, building performance simulation, case study, Occupant Behaviour, optimization}, issn = {Print 1996-3599; Online 1996-8744}, doi = {10.1007/s12273-017-0361-4}, author = {Zsofia Belafi and Tianzhen Hong and Andras Reith} } @article {30312, title = {Spatial Distribution of Internal Heat Gains: A Probabilistic Representation and Evaluation of Its Influence on Cooling Equipment Sizing in Large Office Buildings}, journal = {Energy and Buildings}, year = {2017}, abstract = {

Internal heat gains from occupants, lighting, and plug loads are significant components of the space cooling load in an office building. Internal heat gains vary with time and space. The spatial diversity is significant, even for spaces with the same function in the same building. The stochastic nature of internal heat gains makes determining the peak cooling load to size air-conditioning systems a challenge. The traditional conservative practice of considering the largest internal heat gain among spaces and applying safety factors overestimates the space cooling load, which leads to oversized air-conditioning equipment and chiller plants. In this study, a field investigation of several large office buildings in China led to the development of a new probabilistic approach that represents the spatial diversity of the design internal heat gain of each tenant as a probability distribution function. In a large office building, a central chiller plant serves all air handling units (AHUs), with each AHU serving one or more floors of the building. Therefore, the spatial diversity should be considered differently when the peak cooling loads to size the AHUs and chillers are calculated. The proposed approach considers two different levels of internal heat gains to calculate the peak cooling loads and size the AHUs and chillers in order to avoid oversizing, improve the overall operating efficiency, and thus reduce energy use.

}, keywords = {air handling unit, chiller plant, equipment sizing, internal heat gain, spatial distribution, spatial diversity, stochastic}, doi = {10.1016/j.enbuild.2017.01.044}, author = {Qi Zhang and Da Yan and Jingjing An and Tianzhen Hong and Wei Tian and Kaiyu Sun} } @article {29896, title = {Synthesizing building physics with social psychology: An interdisciplinary framework for context and occupant behavior in office buildings}, year = {2017}, abstract = {

This study introduces an interdisciplinary framework for investigating building-user interaction in office spaces. The framework is a synthesis of theories from building physics and social psychology including social cognitive theory, the theory of planned behavior, and the drivers-needs-actions-systems ontology for energy-related behaviors. The goal of the research framework is to investigate the effects of various behavioral adaptations and building controls (i.e., adjusting thermostats, operating windows, blinds and shades, and switching on/off artificial lights) to determine impacts on occupant comfort and energy-related operational costs in the office environment. This study attempts to expand state-of-the-art understanding of: (1) the environmental, personal, and behavioral drivers motivating occupants to interact with building control systems across four seasons, (2) how occupants{\textquoteright} intention to share controls is influenced by social-psychological variables such as attitudes, subjective norms, and perceived behavioral control in group negotiation dynamic, (3) the perceived ease of usage and knowledge of building technologies, and (4) perceived satisfaction and productivity. To ground the validation of the theoretical framework in diverse office settings and contexts at the international scale, an online survey was designed to collect cross-country responses from office occupants among 14 universities and research centers within the United States, Europe, China, and Australia.

}, author = {Simona D{\textquoteright}Oca and Chien-Fen Chen and Tianzhen Hong and Zsofia Belafi} } @article {30032, title = {Temporal and spatial characteristics of the urban heat island in Beijing and the impact on building design and energy performance}, year = {2017}, abstract = {

With the increased urbanization in most countries worldwide, the urban heat island (UHI) effect, referring to the phenomenon that an urban area has higher ambient temperature than the surrounding rural area, has gained much attention in recent years. Given that Beijing is developing rapidly both in urban population and economically, the UHI effect can be significant. A long-term measured weather dataset from 1961 to 2014 for ten rural stations and seven urban stations in Beijing, was analyzed in this study, to understand the detailed temporal and spatial characteristics of the UHI in Beijing. The UHI effect in Beijing is significant, with an urban-to-rural temperature difference of up to 8{\textcelsius} during the winter nighttime. Furthermore, the impacts of UHIs on building design and energy performance were also investigated. The UHI in Beijing led to an approximately 11\% increase in cooling load and 16\% decrease in heating load in the urban area compared with the rural area, whereas the urban heating peak load decreased 9\% and the cooling peak load increased 7\% because of the UHI effect. This study provides insights into the UHI in Beijing and recommendations to improve building design and decision-making while considering the urban microclimate.

}, keywords = {beijing, building design, Microclimate, Temporal and spatial characteristics, urban heat island}, author = {Ying Cui and Da Yan and Tianzhen Hong and Jingjin Ma} } @article {30315, title = {Ten Questions Concerning Occupant Behavior in Buildings: The Big Picture}, journal = {Building and Environment}, year = {2017}, abstract = {

Occupant behavior has significant impacts on building energy performance and occupant comfort. However, occupant behavior is not well understood and is often oversimplified in the building life cycle, due to its stochastic, diverse, complex, and interdisciplinary nature. The use of simplified methods or tools to quantify the impacts of occupant behavior in building performance simulations significantly contributes to performance gaps between simulated models and actual building energy consumption. Therefore, it is crucial to understand occupant behavior in a comprehensive way, integrating qualitative approaches and data- and model-driven quantitative approaches, and employing appropriate tools to guide the design and operation of low-energy residential and commercial buildings that integrate technological and human dimensions. This paper presents ten questions, highlighting some of the most important issues regarding concepts, applications, and methodologies in occupant behavior research. The proposed questions and answers aim to provide insights into occupant behavior for current and future researchers, designers, and policy makers, and most importantly, to inspire innovative research and applications to increase energy efficiency and reduce energy use in buildings.

}, keywords = {Behavior Modeling, building performance, building simulation, energy use, interdisciplinary, occupant behavior}, author = {Tianzhen Hong and Da Yan and Simona D{\textquoteright}Oca and Chien-Fei Chen} } @article {30303, title = {A Thorough Assessment of China{\textquoteright}s Standard for Energy Consumption of Buildings}, journal = {Energy and Buildings}, year = {2017}, month = {03/2017}, abstract = {

China{\textquoteright}s Design Standard for Energy Efficiency of Public Buildings (the Design Standard) is widely used in the design phase to regulate the energy efficiency of physical assets (envelope, lighting, HVAC) in buildings. However, the standard does not consider many important factors that influence the actual energy use in buildings, and this can lead to gaps between the design estimates and actual energy consumption. To achieve the national energy savings targets defined in the strategic 12th Five-Year Plan, China developed the first standard for energy consumption of buildings GB/T51161-2016 (the Consumption Standard). This study provides an overview of the Consumption Standard, identifies its strengths and weaknesses, and recommends future improvements. The analysis and discussion of the constraint value and the leading value, two key indicators of the energy use intensity, provide insight into the intent and effectiveness of the Consumption Standard. The results indicated that consistency between China{\textquoteright}s Design Standard GB 50189-2015 and the Consumption Standard GB/T51161-2016 could be achieved if the Design Standard used the actual building operations and occupant behavior in calculating the energy use in Chinese buildings. The development of an outcome-based code in the U.S. was discussed in comparison with China{\textquoteright}s Consumption Standard, and this revealed the strengths and challenges associated with implementing a new compliance method based on actual energy use in buildings in the U.S. Overall, this study provides important insights into the latest developments of actual consumption-based building energy standards, and this information should be valuable to building designers and energy policy makers in China and the U.S.

}, keywords = {China, code and standard, energy consumption, energy efficiency, Energy Use Intensity, outcome-based code}, doi = {10.1016/j.enbuild.2017.03.019}, author = {Da Yan and Tianzhen Hong and Cheng Li and Qi Zhang and Jingjing An and shan Hu} } @article {60962, title = {Advances in research and applications of energy-related occupant behavior in buildings}, journal = {Energy and Buildings}, volume = {116}, year = {2016}, month = {03/2016}, pages = {694-702}, abstract = {

Occupant behavior is one of the major factors influencing building energy consumption and contributing to uncertainty in building energy use prediction and simulation. Currently the understanding of occupant behavior is insufficient both in building design, operation and retrofit, leading to incorrect simplifications in modeling and analysis. This paper introduced the most recent advances and current obstacles in modeling occupant behavior and quantifying its impact on building energy use. The major themes include advancements in data collection techniques, analytical and modeling methods, and simulation applications which provide insights into behavior energy savings potential and impact. There has been growing research and applications in this field, but significant challenges and opportunities still lie ahead.

}, keywords = {Behavior Modeling, Building design and operation, building performance simulation, energy use, occupant behavior}, doi = {10.1016/j.enbuild.2015.11.052}, author = {Tianzhen Hong and Sarah C. Taylor-Lange and Simona D{\textquoteright}Oca and Da Yan and Stefano P. Corgnati} } @conference {60968, title = {An Agent-Based Occupancy Simulator for Building Performance Simulation}, year = {2016}, abstract = {

Traditionally, in building energy modeling (BEM) programs, occupancy inputs are deterministic and less indicative of real world scenarios, contributing to discrepancies between simulated and actual energy use in buildings. This paper presents an agent-based occupancy simulator, which models each occupant as an agent with specified movement events and statistics of space uses. To reduce the amount of data inputs, the simulator allows users to group occupants with similar behaviors as an occupant type, and spaces with similar function as a space type. It is a web-based application with friendly graphical user interface, cloud computing, and data storage. A case study is presented to demonstrate the usage of the occupancy simulator and its integration with EnergyPlus and obFMU. It first shows the required data inputs and the results from the occupancy simulator. Then, the generated occupant schedules are used in the EnergyPlus and obFMU simulation to evaluate the impacts of occupant behavior on building energy performance. The simulation results indicate that the occupancy simulator can capture the diversity of space{\textquoteright}s occupancy behavior rather than the static weekly profiles, and can generate realistic occupancy schedules to support building performance simulation.

}, author = {Yixing Chen and Xuan Luo and Tianzhen Hong} } @article {30300, title = {A Comparative Study on Energy Performance of Variable Refrigerant Flow Systems and Variable Air Volume Systems in Office Buildings}, journal = {Applied Energy}, year = {2016}, abstract = {

Variable air volume (VAV) systems and variable refrigerant flow (VRF) systems are popularly used in office buildings. This study investigated VAV and VRF systems in five typical office buildings in China, and compared their air conditioning energy use. Site survey and field measurements were conducted to collect data of building characteristics and operation. Measured cooling electricity use was collected from sub-metering in the five buildings. The sub-metering data, normalized by climate and operating hours, show that VRF systems consumed much less air conditioning energy by up to 70\% than VAV systems. This is mainly due to the different operation modes of both system types leading to much fewer operating hours of the VRF systems. Building simulation was used to quantify the impact of operation modes of VRF and VAV systems on cooling loads using a prototype office building in China. Simulated results show the VRF operation mode leads to much less cooling loads than the VAV operation mode, by 42\% in Hong Kong and 53\% in Qingdao. The VRF systems operated in the part-time-part-space mode enabling occupants to turn on air-conditioning only when needed and when spaces were occupied, while the VAV systems operated in the full-time-full-space mode limiting occupants{\textquoteright} control of operation. The findings provide insights into VRF systems operation and controls as well as its energy performance, which can inform HVAC designers on system selection and building operators or facility managers on improving VRF system operations.\  \ \ 


}, keywords = {building simulation, comparative analysis, energy performance, field measurement, Variable Air Volume (VAV) Systems, Variable Refrigerant Flow (VRF) Systems}, author = {Xinqiao Yu and Da Yan and Kaiyu Sun and Tianzhen Hong and Dandan Zhu} } @article {30297, title = {The Impact of Evaporation Process on Thermal Performance of Roofs - Model Development and Numerical Analysis}, journal = {Energy and Buildings}, year = {2016}, keywords = {Evaporative Cooling, model development, Net zero energy building, Numerical analysis, Passive techniques, Porous building material, Roof thermal performance}, author = {Lei Zhang and Rongpeng Zhang and Yu Zhang and Tianzhen Hong and Qinglin Meng and Yanshan Feng} } @article {30317, title = {Improving the accuracy of energy baseline models for commercial buildings with occupancy data}, journal = {Applied Energy}, year = {2016}, abstract = {

More than 80\% of energy is consumed during operation phase of a building{\textquoteright}s life cycle, so energy efficiency retrofit for existing buildings is considered a promising way to reduce energy use in buildings. The investment strategies of retrofit depend on the ability to quantify energy savings by {\textquotedblleft}measurement and verification{\textquotedblright} (M\&V), which compares actual energy consumption to how much energy would have been used without retrofit (called the {\textquotedblleft}baseline{\textquotedblright} of energy use). Although numerous models exist for predicting baseline of energy use, a critical limitation is that occupancy has not been included as a variable. However, occupancy rate is essential for energy consumption and was emphasized by previous studies. This study develops a new baseline model which is built upon the Lawrence Berkeley National Laboratory (LBNL) model but includes the use of building occupancy data. The study also proposes metrics to quantify the accuracy of prediction and the impacts of variables. However, the results show that including occupancy data does not significantly improve the accuracy of the baseline model, especially for HVAC load. The reasons are discussed further. In addition, sensitivity analysis is conducted to show the influence of parameters in baseline models. The results from this study can help us understand the influence of occupancy on energy use, improve energy baseline prediction by including the occupancy factor, reduce risks of M\&V and facilitate investment strategies of energy efficiency retrofit.

}, keywords = {baseline model, building energy use, Energy Efficiency Retrofit, Measurement and verification, occupancy}, author = {Xin Liang and Tianzhen Hong and Geoffrey Qiping Shen} } @article {60963, title = {Introduction to an occupant behavior motivation survey framework}, year = {2016}, abstract = {

An increasing body of research is underlying the need to foster energy behaviors and interaction with technology as a way to achieve energy savings in office buildings. However, engaging office users into more {\textquotedblleft}forgiving{\textquotedblright} comfort-adaptive behavior is not a trivial task, since neither consequences nor benefits for changing behavior have visible or tangible effects on them personally. Since the 70{\textquoteright}s, survey studies in the field of building science have been used to gain better understanding of multidisciplinary drivers of occupant behavior with respect to comfort and energy requirements in buildings. Rather than focusing on individual behaviors {\textendash} and influencing factors {\textendash} purpose of this survey research is to provide quantitative descriptions on the collective and social motivations within the complexity of different social groups in working environment, under different geographical context, culture and norms. The resultant questionnaire survey emerges as a combination of traditional and adaptive comfort theories, merged with social science theory. The questionnaire explores to what extent the occupant energy-related behavior in working spaces is driven by a motivational sphere influenced by i) comfort requirements, ii) habits, iii) intentions and iv) actual control of building systems. The key elements of the proposed occupant behavior motivational framework are grounded on the Driver Need Action System framework for energy-related behaviors in buildings. Goal of the study is to construct an additional layer of standardized knowledge to enrich the state-of-the-art on energy-related behavior in office buildings.

}, keywords = {DNAs framework, energy-related occupant behavior, motivation, office buildings, questionnaire survey}, author = {Simona D{\textquoteright}Oca and Stefano P. Corgnati and Anna Laura Pisello and Tianzhen Hong} } @conference {60961, title = {Modeling and Simulation of Operational Faults of HVAC Systems Using Energyplus}, year = {2016}, abstract = {

HVAC operations play a significant role among various driving factors to improve energy performance of buildings. Extensive researches have been conducted on the design efficiencies and control strategies of HVAC system, but very few focused on the impacts of its operational faults on the building energy efficiency. Modeling and simulation of operational faults can lead to better understandings of the fault impacts and thus support decision making of timely fault corrections which can further benefit the efficient system operation, improve the indoor thermal comfort, and prolong the equipment service life. Fault modeling is also critical to achieve more accurate and reliable model calibrations. This paper introduces the modeling and simulation of operational faults using EnergyPlus, a comprehensive whole building performance simulation tool. The paper discusses the challenges of operational fault modeling, and compares three approaches to simulate operational faults using EnergyPlus. The paper also introduces the latest development of native fault objects within EnergyPlus. As an example, EnergyPlus version 8.4 is used to investigate the impacts of the integrated thermostat and humidistat faults in a typical office building across several U.S. climate zones. The results demonstrate that the faults create significant impacts on the building energy performance as well as occupant thermal comfort. At last, the paper introduces the future development plan of EnergyPlus for the further improvement of its fault modeling capability.

}, author = {Rongpeng Zhang and Tianzhen Hong} } @article {30316, title = {Occupancy data analytics and prediction: a case study}, year = {2016}, abstract = {

Occupants are a critical impact factor of building energy consumption. Numerous previous studies emphasized the role of occupants and investigated the interactions between occupants and buildings. However, a fundamental problem, how to learn occupancy patterns and predict occupancy schedule, has not been well addressed due to highly stochastic activities of occupants and insufficient data. This study proposes a data mining based approach for occupancy schedule learning and prediction in office buildings. The proposed approach first recognizes the patterns of occupant presence by cluster analysis, then learns the schedule rules by decision tree, and finally predicts the occupancy schedules based on the inducted rules. A case study was conducted in an office building in Philadelphia, U.S. Based on one-year observed data, the validation results indicate that the proposed approach significantly improves the accuracy of occupancy schedule prediction. The proposed approach only requires simple input data (i.e., the time series data of occupant number entering and exiting a building), which is available in most office buildings. Therefore, this approach is practical to facilitate occupancy schedule prediction, building energy simulation and facility operation.

}, keywords = {data mining, Machine learning, occupancy prediction, occupant presence}, author = {Xin Liang and Tianzhen Hong and Geoffrey Qiping Shen} } @article {30299, title = {A Simulation Approach to Estimate Energy Savings Potential of Occupant Behavior Measures}, journal = {Energy and Buildings}, year = {2016}, abstract = {

Occupant behavior in buildings is a leading factor influencing energy use in buildings. Low-cost behavioral solutions have demonstrated significant potential energy savings. Estimating the behavioral savings potential is important for a more effective design of behavior change interventions, which in turn will support more effective energy-efficiency policies. This study introduces a simulation approach to estimate the energy savings potential of occupant behavior measures. First it defines five typical occupant behavior measures in office buildings, then simulates and analyzes their individual and integrated impact on energy use in buildings. The energy performance of the five behavior measures was evaluated using EnergyPlus simulation for a real office building across four typical U.S. climates and two vintages. The Occupancy Simulator was used to simulate the occupant movement in each zone with inputs from the site survey of the case building. Based on the simulation results, the occupant behavior measures can achieve overall site energy savings as high as 22.9\% for individual measures and up to 41.0\% for integrated measures. Although energy savings of behavior measures would vary depending upon many factors, the presented simulation approach is robust and can be adopted for other studies aiming to quantify occupant behavior impact on building performance.

}, keywords = {behavior measure, Behavior Modeling, building performance simulation, energy savings, energyplus, occupant behavior}, author = {Kaiyu Sun and Tianzhen Hong} } @article {60965, title = {Accelerating the energy retrofit of commercial buildings using a database of energy efficiency performance}, journal = {Energy}, year = {2015}, month = {07/2015}, chapter = {738}, abstract = {

Small and medium-sized commercial buildings can be retrofitted to significantly reduce their energy use, however it is a huge challenge as owners usually lack of the expertise and resources to conduct detailed on-site energy audit to identify and evaluate cost-effective energy technologies. This study presents a DEEP (database of energy efficiency performance) that provides a direct resource for quick retrofit analysis of commercial buildings. DEEP, compiled from the results of about ten million EnergyPlus simulations, enables an easy screening of ECMs (energy conservation measures) and retrofit analysis. The simulations utilize prototype models representative of small and mid-size offices and retails in California climates. In the formulation of DEEP, large scale EnergyPlus simulations were conducted on high performance computing clusters to evaluate hundreds of individual and packaged ECMs covering envelope, lighting, heating, ventilation, air-conditioning, plug-loads, and service hot water. The architecture and simulation environment to create DEEP is flexible and can expand to cover additional building types, additional climates, and new ECMs. In this study DEEP is integrated into a web-based retrofit toolkit, the Commercial Building Energy Saver, which provides a platform for energy retrofit decision making by querying DEEP and unearthing recommended ECMs, their estimated energy savings and financial payback.

}, keywords = {building simulation, Energy conservation measure, energy modeling, energyplus, High Performance computing, retrofit}, doi = {10.1016/j.energy.2015.07.107}, author = {Sang Hoon Lee and Tianzhen Hong and Mary Ann Piette and Geof Sawaya and Yixing Chen and Sarah C. Taylor-Lange} } @article {60092, title = {Assessment of the Potential to Achieve Very Low Energy Use in Public Buildings in China with Advanced Window and Shading Systems}, journal = {Buildings}, volume = {5}, year = {2015}, month = {05/2015}, pages = {668-699}, chapter = {668}, abstract = {

As rapid growth in the construction industry continues to occur in China, the increased demand for a higher standard living is driving significant growth in energy use and demand across the country. Building codes and standards have been implemented to head off this trend, tightening prescriptive requirements for fenestration component measures using methods similar to the US model energy code American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1. The objective of this study is to (a) provide an overview of applicable code requirements and current efforts within China to enable characterization and comparison of window and shading products, and (b) quantify the load reduction and energy savings potential of several key advanced window and shading systems, given the divergent views on how space conditioning requirements will be met in the future.

System-level heating and cooling loads and energy use performance were evaluated for a code-compliant large office building using the EnergyPlus building energy simulation program. Commercially-available, highly-insulating, low-emittance windows were found to produce 24-66\% lower perimeter zone HVAC electricity use compared to the mandated energy-efficiency standard in force (GB 50189-2005) in cold climates like Beijing. Low-e windows with operable exterior shading produced up to 30-80\% reductions in perimeter zone HVAC electricity use in Beijing and 18-38\% reductions in Shanghai compared to the standard. The economic context of China is unique since the cost of labor and materials for the building industry is so low. Broad deployment of these commercially available technologies with the proper supporting infrastructure for design, specification, and verification in the field would enable significant reductions in energy use and greenhouse gas emissions in the near term.

}, keywords = {building, China, energy efficiency, shading, windows}, doi = {10.3390/buildings5020668}, author = {Eleanor S. Lee and Xiufeng Pang and Andrew McNeil and Sabine Hoffmann and Anothai Thanachareonkit and Zhengrong Li and Yong Ding} } @article {61107, title = {Commercial Building Energy Saver: An energy retrofit analysis toolkit}, journal = {Applied Energy}, volume = {159}, year = {2015}, month = {9/2015}, chapter = {298}, abstract = {

Small commercial buildings in the United States consume 47\% of the total primary energy of the buildings sector. Retrofitting small and medium commercial buildings poses a huge challenge for owners because they usually lack the expertise and resources to identify and evaluate cost-effective energy retrofit strategies. This paper presents the Commercial Building Energy Saver (CBES), an energy retrofit analysis toolkit, which calculates the energy use of a building, identifies and evaluates retrofit measures in terms of energy savings, energy cost savings and payback. The CBES Toolkit includes a web app (APP) for end users and the CBES Application Programming Interface (API) for integrating CBES with other energy software tools. The toolkit provides a rich set of features including: (1) Energy Benchmarking providing an Energy Star score, (2) Load Shape Analysis to identify potential building operation improvements, (3) Preliminary Retrofit Analysis which uses a custom developed pre-simulated database and, (4) Detailed Retrofit Analysis which utilizes real-time EnergyPlus simulations. CBES includes 100 configurable energy conservation measures (ECMs) that encompass IAQ, technical performance and cost data, for assessing 7 different prototype buildings in 16 climate zones in California and 6 vintages. A case study of a small office building demonstrates the use of the toolkit for retrofit analysis. The development of CBES provides a new contribution to the field by providing a straightforward and uncomplicated decision making process for small and medium business owners, leveraging different levels of assessment dependent upon user background, preference and data availability.

}, keywords = {Building Technologies Department, Building Technology and Urban Systems Division, buildings, buildings energy efficiency, Commercial Building Systems, conservation measures, energy efficiency, energy use, energyplus, External, Retrofit Energy, simulation research}, doi = {10.1016/j.apenergy.2015.09.002}, author = {Tianzhen Hong and Mary Ann Piette and Yixing Chen and Sang Hoon Lee and Sarah C. Taylor-Lange and Rongpeng Zhang and Kaiyu Sun and Phillip N. Price} } @article {59960, title = {Data Analysis and Stochastic Modeling of Lighting Energy Use in Large Office Buildings in China}, journal = {Energy and Buildings}, volume = {86}, year = {2015}, month = {01/2015}, pages = {275-287}, abstract = {

Lighting consumes about 20\% to 40\% of the total electricity use in large office buildings in China. Commonly in building simulations, static time schedules for typical weekdays, weekends and holidays are assumed to represent the dynamics of lighting energy use in buildings. This approach does not address the stochastic nature of lighting energy use, which can be influenced by occupant behavior in buildings. This study analyzes the main characteristics of lighting energy use over various timescales, based on the statistical analysis of measured lighting energy use data from 15 large office buildings in Beijing and Hong Kong. It was found that in these large office buildings, the 24-hourly variation in lighting energy use was mainly driven by the schedules of the building occupants. Outdoor illuminance levels had little impact on lighting energy use due to the lack of automatic daylighting controls (an effective retrofit measure to reduce lighting energy use) and the relatively small perimeter area exposed to natural daylight. A stochastic lighting energy use model for large office buildings was further developed to represent diverse occupant activities, at six different time periods throughout a day, and also the annual distribution of lighting power across these periods. The model was verified using measured lighting energy use from the 15 buildings. The developed stochastic lighting model can generate more accurate lighting schedules for use in building energy simulations, improving the simulation accuracy of lighting energy use in real buildings.

}, keywords = {building simulation, energy use, Lighting modeling, occupant behavior, office buildings, Poisson distribution, stochastic modeling}, doi = {10.1016/j.enbuild.2014.09.071}, author = {Xin Zhou and Da Yan and Tianzhen Hong and Xiaoxin Ren} } @article {59958, title = {Data Mining of Space Heating System Performance in Affordable Housing}, journal = {Building and Environment}, volume = {89}, year = {2015}, month = {07/2015}, pages = {1-13}, abstract = {

The space heating in residential buildings accounts for a considerable amount of the primary energy use. Therefore, understanding the operation and performance of space heating systems becomes crucial in improving occupant comfort while reducing energy use. This study investigated the behavior of occupants adjusting their thermostat settings and heating system operations in a 62-unit affordable housing complex in Revere, Massachusetts, USA. The data mining methods, including clustering approach and decision trees, were used to ascertain occupant behavior patterns. Data tabulating ON/OFF space heating states was assessed, to provide a better understanding of the intermittent operation of space heating systems in terms of system cycling frequency and the duration of each operation. The decision tree was used to verify the link between room temperature settings, house and heating system characteristics and the heating energy use. The results suggest that the majority of apartments show fairly constant room temperature profiles with limited variations during a day or between weekday and weekend. Data clustering results revealed six typical patterns of room temperature profiles during the heating season. Space heating systems cycled more frequently than anticipated due to a tight range of room thermostat settings and potentially oversized heating capacities. The results from this study affirm data mining techniques are an effective method to analyze large datasets and extract hidden patterns to inform design and improve operations.

}, keywords = {affordable housing, building simulation, clustering, data mining, decision tree, occupant behavior, space heating}, doi = {10.1016/j.buildenv.2015.02.009}, author = {Xiaoxin Ren and Da Yan and Tianzhen Hong} } @article {59988, title = {A Data-mining Approach to Discover Patterns of Window Opening and Closing Behavior in Offices}, year = {2015}, abstract = {

Understanding the relationship between occupant behaviors and building energy consumption is one of the most effective ways to bridge the gap between predicted and actual energy consumption in buildings. However effective methodologies to remove the impact of other variables on building energy consumption and isolate the leverage of the human factor precisely are still poorly investigated. Moreover, the effectiveness of statistical and data mining approaches in finding meaningful correlations in data is largely undiscussed in literature. This study develops a framework combining statistical analysis with two data-mining techniques, cluster analysis and association rules mining, to identify valid window operational patterns in measured data. Analyses are performed on a data set with measured indoor and outdoor physical parameters and human interaction with operable windows in 16 offices. Logistic regression was first used to identify factors influencing window opening and closing behavior. Clustering procedures were employed to obtain distinct behavioral patterns, including motivational, opening duration, interactivity and window position patterns. Finally the clustered patterns constituted a base for association rules segmenting the window opening behaviors into two archetypal office user profiles for which different natural ventilation strategies as well as robust building design recommendations that may be appropriate. Moreover, discerned working user profiles represent more accurate input to building energy modeling programs, to investigate the impacts of typical window opening behavior scenarios on energy use, thermal comfort and productivity in office buildings

}, author = {Simona D{\textquoteright}Oca and Tianzhen Hong} } @article {59986, title = {DEEP: A Database of Energy Efficiency Performance to Accelerate Energy Retrofitting of Commercial Buildings}, year = {2015}, abstract = {

The paper presents a method and process to establish a database of energy efficiency performance (DEEP) to enable quick and accurate assessment of energy retrofit of commercial buildings. DEEP was compiled from results of about 35 million EnergyPlus simulations. DEEP provides energy savings for screening and evaluation of retrofit measures targeting the small and medium-sized office and retail buildings in California. The prototype building models are developed for a comprehensive assessment of building energy performance based on DOE commercial reference buildings and the California DEER prototype buildings. The prototype buildings represent seven building types across six vintages of constructions and 16 California climate zones. DEEP uses these prototypes to evaluate energy performance of about 100 energy conservation measures covering envelope, lighting, heating, ventilation, air-conditioning, plug-loads, and domestic hot water. DEEP consists the energy simulation results for individual retrofit measures as well as packages of measures to consider interactive effects between multiple measures. The large scale EnergyPlus simulations are being conducted on the super computers at the National Energy Research Scientific Computing Center of Lawrence Berkeley National Laboratory. The pre-simulation database is a part of an on-going project to develop a web-based retrofit toolkit for small and medium-sized commercial buildings in California, which provides real-time energy retrofit feedback by querying DEEP with recommended measures, estimated energy savings and financial payback period based on users{\textquoteright} decision criteria of maximizing energy savings, energy cost savings, carbon reduction, or payback of investment. The pre-simulated database and associated comprehensive measure analysis enhances the ability to performance assessments of retrofits to reduce energy use for small and medium buildings and business owners who typically do not have resources to conduct costly building energy audit. DEEP will be migrated into the DEnCity - DOE{\textquoteright}s Energy City, which integrates large-scale energy data for multi-purpose, open, and dynamic database leveraging diverse source of existing simulation data.

}, author = {Sang Hoon Lee and Tianzhen Hong and Geof Sawaya and Yixing Chen and Mary Ann Piette} } @article {60960, title = {Development and validation of a new variable refrigerant flow systemmodel in EnergyPlus}, journal = {Energy and Buildings}, volume = {117}, year = {2015}, month = {9/2015}, chapter = {399}, abstract = {

Variable refrigerant flow (VRF) systems vary the refrigerant flow to meet the dynamic zone thermalloads, leading to more efficient operations than other system types. This paper introduces a new modelthat simulates the energy performance of VRF systems in the heat pump (HP) operation mode. Com-pared with the current VRF-HP models implemented in EnergyPlus, the new VRF system model has morecomponent models based on physics and thus has significant innovations in: (1) enabling advanced con-trols, including variable evaporating and condensing temperatures in the indoor and outdoor units, andvariable fan speeds based on the temperature and zone load in the indoor units, (2) adding a detailedrefrigerant pipe heat loss calculation using refrigerant flow rate, operational conditions, pipe length, andpipe insulation materials, (3) improving accuracy of simulation especially in partial load conditions, and(4) improving the usability of the model by significantly reducing the number of user input performancecurves. The VRF-HP model is implemented in EnergyPlus and validated with measured data from fieldtests. Results show that the new VRF-HP model provides more accurate estimate of the VRF-HP systemperformance, which is key to determining code compliance credits as well as utilities incentive for VRFtechnologies.

}, keywords = {building simulation, energy modeling, energyplus, Heat pump, model validation, Variable refrigerant flow}, doi = {10.1016/j.enbuild.2015.09.023}, author = {Tianzhen Hong and Kaiyu Sun and Rongpeng Zhang and Ryohei Hinokuma and Shinichi Kasahara and Yoshinori Yura} } @article {60955, title = {Energy retrofit analysis toolkit for commercial buildings: A review}, volume = {89}, year = {2015}, month = {09/2015}, pages = {1087-1100}, publisher = {Elsevier Ltd.}, chapter = {1087}, abstract = {

Retrofit analysis toolkits can be used to optimize energy or cost savings from retrofit strategies, accelerating the adoption of ECMs (energy conservation measures) in buildings. This paper provides an up-todate review of the features and capabilities of 18 energy retrofit toolkits, including ECMs and the calculation engines. The fidelity of the calculation techniques, a driving component of retrofit toolkits, were evaluated. An evaluation of the issues that hinder effective retrofit analysis in terms of accessibility, usability, data requirement, and the application of efficiency measures, provides valuable insights into advancing the field forward. Following this review the general concepts were determined: (1) toolkits developed primarily in the private sector use empirically data-driven methods or benchmarking to provide ease of use, (2) almost all of the toolkits which used EnergyPlus or DOE-2 were freely accessible, but suffered from complexity, longer data input and simulation run time, (3) in general, there appeared to be a fine line between having too much detail resulting in a long analysis time or too little detail which sacrificed modeling fidelity. These insights provide an opportunity to enhance the design and development of existing and new retrofit toolkits in the future.

}, keywords = {Building energy retrofit, Energy conservation measures, Energy efficiency, Energy simulation, Retrofit analysis tools, Web-based applications}, doi = {10.1016/j.energy.2015.06.112}, author = {Sang Hoon Lee and Tianzhen Hong and Mary Ann Piette and Sarah C. Taylor-Lange} } @article {60932, title = {Green, Clean, \& Mean: Pushing the Energy Envelope in Tech Industry Buildings}, year = {2015}, month = {05/2015}, publisher = {Lawrence Berkeley National Laboratory}, abstract = {

When it comes to innovation in energy and building performance, one can expect leading-edge activity from the technology sector. As front-line innovators in design, materials science, and information management, developing and operating high-performance buildings is a natural extension of their core business.

The energy choices made by technology companies have broad importance given their influence on society at large as well as the extent of their own energy footprint. Microsoft, for example, has approximately 250 facilities around the world (30 million square feet of floor area), with significant aggregate energy use of approximately 4 million kilowatt-hours per day.

There is a degree of existing documentation of efforts to design, build, and operate facilities in the technology sector. However, the material is fragmented and typically looks only at a single company, or discrete projects within a company.Yet, there is no single resource for corporate planners and decision makers that takes stock of the opportunities and documents sector-specific case studies in a structured manner. This report seeks to fill that gap, doing so through a combination of generalized technology assessments ({\textquotedblleft}Key Strategies{\textquotedblright}) and case studies ({\textquotedblleft}Flagship Projects{\textquotedblright}).

}, author = {Evan Mills and Jessica Granderson and Wanyu R. Chan and Richard C. Diamond and Philip Haves and Bruce Nordman and Paul A. Mathew and Mary Ann Piette and Gerald Robinson and Stephen E. Selkowitz} } @article {59957, title = {An Insight into Actual Energy Use and Its Drivers in High-Performance Buildings}, year = {2015}, abstract = {

Using portfolio analysis and individual detailed case studies, we studied the energy performance and drivers of energy use in 51 high-performance office buildings in the U.S., Europe, China, and other parts of Asia. Portfolio analyses revealed that actual site energy use intensity (EUI) of the study buildings varied by a factor of as much as 11, indicating significant variation in real energy use in HPBs worldwide. Nearly half of the buildings did not meet the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Standard 90.1-2004 energy target, raising questions about whether a building{\textquoteright}s certification as high performing accurately indicates that a building is energy efficient and suggesting that improvement in the design and operation of HPBs is needed to realize their energy-saving potential. We studied the influence of climate, building size, and building technologies on building energy performance and found that although all are important, none are decisive factors in building energy use. EUIs were widely scattered in all climate zones. There was a trend toward low energy use in small buildings, but the correlation was not absolute; some small HPBs exhibited high energy use, and some large HPBs exhibited low energy use. We were unable to identify a set of efficient technologies that correlated directly to low EUIs. In two case studies, we investigated the influence of occupant behavior as well as operation and maintenance on energy performance and found that both play significant roles in realizing energy savings. We conclude that no single factor determines the actual energy performance of HPBs, and adding multiple efficient technologies does not necessarily improve building energy performance; therefore, an integrated design approach that takes account of climate, technology, occupant behavior, and operations and maintenance practices should be implemented to maximize energy savings in HPBs. These findings are intended to help architects, engineers, operators, and policy makers improve the design and operation of HPBs.

}, keywords = {actual energy use, building technologies, driving factors, high-performance buildings, integrated design, performance rating}, author = {Cheng Li and Tianzhen Hong and Da Yan} } @article {59987, title = {Occupancy Schedules Learning Process Through a Data Mining Framework}, journal = {Energy and Buildings}, volume = {88}, year = {2015}, month = {02/2015}, pages = {395-408}, abstract = {

Building occupancy is a paramount factor in building energy simulations. Specifically, lighting, plug loads, HVAC equipment utilization, fresh air requirements and internal heat gain or loss greatly depends on the level of occupancy within a building. Developing the appropriate methodologies to describe and reproduce the intricate network responsible for human-building interactions are needed. Extrapolation of patterns from big data streams is a powerful analysis technique which will allow for a better understanding of energy usage in buildings. A three-step data mining framework is applied to discover occupancy patterns in office spaces. First, a data set of 16 offices with 10\ min interval occupancy data, over a two year period is mined through a decision tree model which predicts the occupancy presence. Then a rule induction algorithm is used to learn a pruned set of rules on the results from the decision tree model. Finally, a cluster analysis is employed in order to obtain consistent patterns of occupancy schedules. The identified occupancy rules and schedules are representative as four archetypal working profiles that can be used as input to current building energy modeling programs, such as EnergyPlus or IDA-ICE, to investigate impact of occupant presence on design, operation and energy use in office buildings.

}, keywords = {Behavioral Pattern, building simulation, data mining, Occupancy schedule, occupant behavior, Office Building}, doi = {10.1016/j.enbuild.2014.11.065}, author = {Simona D{\textquoteright}Oca and Tianzhen Hong} } @article {60948, title = {Occupant Behavior Modeling for Building Performance Simulation: Current State and Future Challenges}, journal = {Energy and Buildings}, volume = {107}, year = {2015}, month = {11/2015}, pages = {264-278}, abstract = {

Occupant behavior is now widely recognized as a major contributing factor to uncertainty of building performance. While a surge of research on the topic has occurred over the past four decades, and particularly the past few years, there are many gaps in knowledge and limitations to current methodologies. This paper outlines the state-of-the-art research, current obstacles and future needs and directions for the following four-step iterative process: (1) occupant monitoring and data collection, (2) model development, (3) model evaluation, and (4) model implementation into building simulation tools. Major themes include the need for greater rigor in experimental methodologies; detailed, honest, and candid reporting of methods and results; and development of an efficient means to implement occupant behavior models and integrate them into building energy modeling programs.

}, keywords = {building simulation, energy efficiency, energy modeling, energy use, occupant behavior}, doi = {10.1016/j.enbuild.2015.08.032}, author = {Da Yan and William O{\textquoteright}Brien and Tianzhen Hong and Xiaohang Feng and H. Burak Gunay and Farhang Tahmasebi and Ardeshir Mahdavi} } @article {60959, title = {An Ontology to Represent Energy-Related Occupant Behavior in Buildings. Part II: Implementation of the DNAS framework using an XML schema}, journal = {Building and Environment}, volume = {94}, year = {2015}, month = {08/2015}, pages = {196-205}, abstract = {

Energy-related occupant behavior in buildings is difficult to define and quantify, yet critical to our understanding of total building energy consumption. Part I of this two-part paper introduced the DNAS (Drivers, Needs, Actions and Systems) framework, to standardize the description of energy-related occupant behavior in buildings. Part II of this paper implements the DNAS framework into an XML (eXtensible Markup Language) schema, titled {\textquoteleft}occupant behavior XML{\textquoteright} (obXML). The obXML schema is used for the practical implementation of the DNAS framework into building simulation tools. The topology of the DNAS framework implemented in the obXML schema has a main root element OccupantBehavior, linking three main elements representing Buildings, Occupants and Behaviors. Using the schema structure, the actions of turning on an air conditioner and closing blinds provide two examples of how the schema standardizes these actions using XML. The obXML schema has inherent flexibility to represent numerous, diverse and complex types of occupant behaviors in buildings, and it can also be expanded to encompass new types of behaviors. The implementation of the DNAS framework into the obXML schema will facilitate the development of occupant information modeling (OIM) by providing interoperability between occupant behavior models and building energy modeling programs.

}, keywords = {building energy consumption, building simulation, energy modeling, obXML, occupant behavior, XML schema}, doi = {10.1016/j.buildenv.2015.08.006}, author = {Tianzhen Hong and Simona D{\textquoteright}Oca and Sarah C. Taylor-Lange and William J. N. Turner and Yixing Chen and Stefano P. Corgnati} } @article {59959, title = {An Ontology to Represent Energy-related Occupant Behavior in Buildings Part I: Introduction to the DNAs Framework}, journal = {Building and Environment}, volume = {92}, year = {2015}, month = {10/2015}, pages = {764-777}, abstract = {

Reducing energy consumption in the buildings sector requires significant changes, but technology alone may fail to guarantee efficient energy performance. Human behavior plays a pivotal role in building design, operation, management and retrofit, and is a crucial positive factor for improving the indoor environment, while reducing energy use at low cost. Over the past 40 years, a substantial body of literature has explored the impacts of human behavior on building technologies and operation. Often, need-action-event cognitive theoretical frameworks were used to represent human-machine interactions. In Part I of this paper a review of more than 130 published behavioral studies and frameworks was conducted. A large variety of data-driven behavioral models have been developed based on field monitoring of the human-building-system interaction. Studies have emerged scattered geographically around the world that lack in standardization and consistency, thus leading to difficulties when comparing one with another. To address this problem, an ontology to represent energy-related occupant behavior in buildings is presented. Accordingly, the technical DNAs framework is developed based on four key components: i) the Drivers of behavior, ii) the Needs of the occupants, iii) the Actions carried out by the occupants, and iv) the building systems acted upon by the occupants. This DNAs framework is envisioned to support the international research community to standardize a systematic representation of energy-related occupant behavior in buildings. Part II of this paper further develops the DNAs framework as an XML (eXtensible Markup Language) schema, obXML, for exchange of occupant information modeling and integration with building simulation tools.

}, keywords = {Building energy, human-building-system interaction, modeling, occupant behavior, ontology, simulation}, doi = {10.1016/j.buildenv.2015.02.019}, author = {Tianzhen Hong and Simona D{\textquoteright}Oca and William J. N. Turner and Sarah C. Taylor-Lange} } @article {60964, title = {A pattern-based automated approach to building energy model calibration}, year = {2015}, abstract = {

Building model calibration is critical in bringing simulated energy use closer to the actual consumption. This paper presents a novel, automated model calibration approach that uses logic linking parameter tuning with bias pattern recognition to overcome some of the disadvantages associated with traditional calibration processes. The pattern-based process contains four key steps: (1) running the original precalibrated energy model to obtain monthly simulated electricity and gas use; (2) establishing a pattern bias, either Universal or Seasonal Bias, by comparing load shape patterns of simulated and actual monthly energy use; (3) using programmed logic to select which parameter to tune first based on bias pattern, weather and input parameter interactions; and (4) automatically tuning the calibration parameters and checking the progress using pattern-fit criteria. The automated calibration algorithm was implemented in the Commercial Building Energy Saver, a web-based building energy retrofit analysis toolkit. The proof of success of the methodology was demonstrated using a case study of an office building located in San Francisco. The case study inputs included the monthly electricity bill, monthly gas bill, original building model and weather data with outputs resulting in a calibrated model that more closely matched that of the actual building energy use profile. The novelty of the developed calibration methodology lies in linking parameter tuning with the underlying logic associated with bias pattern identification. Although there are some limitations to this approach, the pattern-based automated calibration methodology can be universally adopted as an alternative to manual or hierarchical calibration approaches.

}, author = {Kaiyu Sun and Tianzhen Hong and Sarah C. Taylor-Lange and Mary Ann Piette} } @article {59961, title = {Simulation of Occupancy in Buildings}, journal = {Energy and Buildings}, volume = {87}, year = {2015}, month = {01/2015}, pages = {348-359}, abstract = {

Occupants are involved in a variety of activities in buildings, which drive them to move among rooms, enter or leave a building. In this study, occupancy is defined at four levels and varies with time: (1) the number of occupants in a building, (2) occupancy status of a space, (3) the number of occupants in a space, and (4) the space location of an occupant. Occupancy has a great influence on internal loads and ventilation requirement, thus building energy consumption. Based on a comprehensive review and comparison of literature on occupancy modeling, three representative occupancy models, corresponding to the levels 2{\textendash}4, are selected and implemented in a software module. Main contributions of our study include: (1) new methods to classify occupancy models, (2) the review and selection of various levels of occupancy models, and (3) new methods to integrate these model into a tool that can be used in different ways for different applications and by different audiences. The software can simulate more detailed occupancy in buildings to improve the simulation of energy use, and better evaluate building technologies in buildings. The occupancy of an office building is simulated as an example to demonstrate the use of the software module.

}, keywords = {building simulation, co-simulation, occupancy, occupant behavior, software module, stochastic modeling}, doi = {10.1016/j.enbuild.2014.11.067}, author = {Xiaohang Feng and Da Yan and Tianzhen Hong} } @article {60351, title = {Simulation Speed Analysis and Improvements of Modelica Models for Building Energy Simulation}, year = {2015}, abstract = {

This paper presents an approach for speeding up Modelica models. Insight is provided into how Modelica models are solved and what determines the tool{\textquoteright}s computational speed. Aspects such as algebraic loops, code efficiency and integrator choice are discussed. This is illustrated using simple building simulation examples and Dymola. The generality of the work is in some cases verified using OpenModelica. Using this approach, a medium sized office building including building envelope, heating ventilation and air conditioning (HVAC) systems and control strategy can be simulated at a speed five hundred times faster than real time.

}, author = {Filip Jorissen and Michael Wetter and Lieve Helsen} } @article {60966, title = {Updates to the China Design Standard for Energy Efficiency in Public Buildings}, journal = {Energy Policy}, volume = {87}, year = {2015}, month = {12/2015}, pages = {187-198}, abstract = {

The China Design Standard for Energy Efficiency in public buildings (GB 50189) debuted in 2005 when China completed the 10th Five-Year Plan. GB 50189-2005 played a crucial role in regulating the energy efficiency in Chinese commercial buildings. The standard was recently updated in 2014 to increase energy savings targets by 30\% compared with the 2005 standard. This paper reviews the major changes to the standard, including expansion of energy efficiency coverage and more stringent efficiency requirements. The paper also discusses the interrelationship of the design standard with China{\textquoteright}s other building energy standards. Furthermore, comparisons are made with ASHRAE Standard 90.1-2013 to provide contrasting differences in efficiency requirements. Finally recommendations are provided to guide the future standard revision, focusing on three areas: (1) increasing efficiency requirements of building envelope and HVAC systems, (2) adding a whole-building performance compliance pathway and implementing a ruleset based automatic code baseline model generation in an effort to reduce the discrepancies of baseline models created by different tools and users, and (3) adding inspection and commissioning requirements to ensure building equipment and systems are installed correctly and operate as designed.

}, keywords = {building design, building energy standard, China, energy efficiency, GB 50189, Public buildings}, doi = {10.1016/j.enpol.2015.09.013}, author = {Tianzhen Hong and Cheng Li and Da Yan} } @article {59965, title = {Comparison of Building Energy Use Data Between the United States and China}, journal = {Energy and Buildings}, volume = {78}, year = {2014}, month = {08/2014}, pages = {165-175}, abstract = {

Buildings in the United States and China consumed 41\% and 28\% of the total primary energy in 2011, respectively. Good energy data are the cornerstone to understanding building energy performance and supporting research, design, operation, and policy making for low energy buildings. This paper presents initial outcomes from a joint research project under the U.S.{\textendash}China Clean Energy Research Center for Building Energy Efficiency. The goal is to decode the driving forces behind the discrepancy of building energy use between the two countries; identify gaps and deficiencies of current building energy monitoring, data collection, and analysis; and create knowledge and tools to collect and analyze good building energy data to provide valuable and actionable information for key stakeholders. This paper first reviews and compares several popular existing building energy monitoring systems in both countries. Next a standard energy data model is presented. A detailed, measured building energy data comparison was conducted for a few office buildings in both countries. Finally issues of data collection, quality, sharing, and analysis methods are discussed. It was found that buildings in both countries performed very differently, had potential for deep energy retrofit, but that different efficiency measures should apply.

}, keywords = {buildings, comparison, data analysis, data model, Energy benchmarking, energy monitoring system, energy use, retrofit}, doi = {10.1016/j.enbuild.2014.04.031}, author = {Jianjun Xia and Tianzhen Hong and Qi Shen and Wei Feng and Le Yang and Piljae Im and Alison Lu and Mahabir Bhandari} } @article {57756, title = {Data and Analytics to Inform Energy Retrofit of High Performance Buildings}, journal = {Applied Energy}, volume = {126}, year = {2014}, month = {08/2014}, pages = {90-106}, publisher = {Elsevier}, abstract = {

Buildings consume more than one-third of the world{\textquoteright}s primary energy. Reducing energy use in buildings with energy efficient technologies is feasible and also driven by energy policies such as energy benchmarking, disclosure, rating, and labeling in both the developed and developing countries. Current energy retrofits focus on the existing building stocks, especially older buildings, but the growing number of new high performance buildings built around the world raises a question that how these buildings perform and whether there are retrofit opportunities to further reduce their energy use. This is a new and unique problem for the building industry. Traditional energy audit or analysis methods are inadequate to look deep into the energy use of the high performance buildings. This study aims to tackle this problem with a new holistic approach powered by building performance data and analytics. First, three types of measured data are introduced, including the time series energy use, building systems operating conditions, and indoor and outdoor environmental parameters. An energy data model based on the ISO Standard 12655 is used to represent the energy use in buildings in a three-level hierarchy. Secondly, a suite of analytics were proposed to analyze energy use and to identify retrofit measures for high performance buildings. The data-driven analytics are based on monitored data at short time intervals, and cover three levels of analysis {\textendash} energy profiling, benchmarking and diagnostics. Thirdly, the analytics were applied to a high performance building in California to analyze its energy use and identify retrofit opportunities, including: (1) analyzing patterns of major energy end-use categories at various time scales, (2) benchmarking the whole building total energy use as well as major end-uses against its peers, (3) benchmarking the power usage effectiveness for the data center, which is the largest electricity consumer in this building, and (4) diagnosing HVAC equipment using detailed time-series operating data. Finally, a few energy efficiency measures were identified for retrofit, and their energy savings were estimated to be 20\% of the whole-building electricity consumption. Based on the analyses, the building manager took a few steps to improve the operation of fans, chillers, and data centers, which will lead to actual energy savings. This study demonstrated that there are energy retrofit opportunities for high performance buildings and detailed measured building performance data and analytics can help identify and estimate energy savings and to inform the decision making during the retrofit process. Challenges of data collection and analytics were also discussed to shape best practice of retrofitting high performance buildings.

}, keywords = {Analytics, data model, Energy benchmarking, energy use, High performance buildings, retrofit}, doi = {10.1016/j.apenergy.2014.03.052}, author = {Tianzhen Hong and Le Yang and David Hill and Wei Feng} } @article {60154, title = {Development of Diagnostic and Measurement and Verification Tools for Commercial Buildings}, year = {2014}, month = {09/2014}, institution = {California Energy Commission}, abstract = {

This research developed new measurement and verification tools and new automated fault detection and diagnosis tools, and deployed them in the Universal Translator. The Universal Translator is a tool, developed by Pacific Gas and Electric, that manages large sets of measured data from building control systems and enables off-line analysis of building performance. There were four technical projects following the program administration tasks identified as Project 1:

  1. Program Administration
  2. Methods and Tools to Reduce the Cost of Measurement and Verification.
  3. Fault Detection and Diagnostics for Commercial Heating, Ventilating, and Air- Conditioning Systems.
  4. Test Procedures and Tools to Characterize Fan and Duct System Performance in Large Commercial Buildings.
  5. Universal Translator Development: Integration of Application Programming Interface.

Project 1 consisted of administrative tasks related to the project.

Project 2 addressed the need for less expensive measurement and verification tools to determine the costs and benefits of retrofits and retro-commissioning at both the individual building level and the utility program level.

Project 3 extended previous work on fault detection and diagnosis to additional systems and subsystems, including dual duct heating, ventilating and air-conditioning systems and fan-coil terminal units.

Project 4 combined previous work on duct leakage and fan modeling to develop a performance assessment method for existing fan/duct systems that could also be used in the analysis of retrofit measures identified by the tools in Projects 2 and 3 using the EnergyPlus simulation program to help select the most cost-effective package of improvements.

Some of the diagnostic methods and tools developed in projects 2 through 4 were incorporated in the Universal Translator via a new application programming interface that was specified, developed and tested in Project 5. Combined, these tools support analyses of energy savings produced by new construction commissioning, retro-commissioning, improved routine operations and code compliance. The new application programming interface could also facilitate future development, testing and deployment of new diagnostic tools.

}, keywords = {application programming interface, fault detection and diagnosis, M\&V, Measurement and verification, Universal Translator}, author = {Philip Haves and Craig P. Wray and David A. Jump and Daniel Veronica and Christopher Farley} } @article {59969, title = {Integrated Design for High Performance Buildings}, year = {2014}, author = {Tianzhen Hong and Cheng Li and Richard C. Diamond and Da Yan and Qi Zhang and Xin Zhou and Siyue Guo and Kaiyu Sun and Jingyi Wang} } @conference {59967, title = {A New Model to Simulate Energy Performance of VRF Systems}, year = {2014}, abstract = {

This paper presents a new model to simulate energy performance of variable refrigerant flow (VRF) systems in heat pump operation mode (either cooling or heating is provided but not simultaneously). The main improvement of the new model is the introduction of the evaporating and condensing temperature in the indoor and outdoor unit capacity modifier functions. The independent variables in the capacity modifier functions of the existing VRF model in EnergyPlus are mainly room wet-bulb temperature and outdoor dry-bulb temperature in cooling mode and room dry-bulb temperature and outdoor wet-bulb temperature in heating mode. The new approach allows compliance with different specifications of each indoor unit so that the modeling accuracy is improved. The new VRF model was implemented in a custom version of EnergyPlus 7.2. This paper first describes the algorithm for the new VRF model, which is then used to simulate the energy performance of a VRF system in a Prototype House in California that complies with the requirements of Title 24 {\textendash} the California Building Energy Efficiency Standards. The VRF system performance is then compared with three other types of HVAC systems: the Title 24-2005 Baseline system, the traditional High Efficiency system, and the EnergyStar Heat Pump system in three typical California climates: Sunnyvale, Pasadena and Fresno. Calculated energy savings from the VRF systems are significant. The HVAC site energy savings range from 51 to 85\%, while the TDV (Time Dependent Valuation) energy savings range from 31 to 66\% compared to the Title 24 Baseline Systems across the three climates. The largest energy savings are in Fresno climate followed by Sunnyvale and Pasadena. The paper discusses various characteristics of the VRF systems contributing to the energy savings. It should be noted that these savings are calculated using the Title 24 prototype House D under standard operating conditions. Actual performance of the VRF systems for real houses under real operating conditions will vary.

}, author = {Tianzhen Hong and Xiufeng Pang and Oren Schetrit and Liping Wang and Shinichi Kasahara and Yoshinori Yura and Ryohei Hinokuma} } @article {58863, title = {Review of Existing Energy Retrofit Tools}, year = {2014}, author = {Sang Hoon Lee and Tianzhen Hong and Mary Ann Piette} } @conference {59966, title = {Revisit of Energy Use and Technologies of High Performance Buildings}, booktitle = {2014 ASHRAE Annual Conference}, year = {2014}, month = {06/2014}, publisher = {ASHRAE}, organization = {ASHRAE}, address = {Seattle, WA}, abstract = {

Energy consumed by buildings accounts for one third of the world{\textquoteright}s total primary energy use. Associated with the conscious of energy savings in buildings, High Performance Buildings (HPBs) has surged across the world, with wide promotion and adoption of various performance rating and certification systems. It is valuable to look into the actual energy performance of HPBs and to understand their influencing factors.

To shed some light on this topic, this paper conducted a series of portfolio analysis based on a database of 51 high performance office buildings across the world. Analyses showed that the actual site Energy Use Intensity (EUI) of the 51 buildings varied by a factor of up to 11, indicating a large scale of variation of the actual energy performance of the current HPBs. Further analysis of the correlation between EUI and climate elucidated ubiquitous phenomenon of EUI scatter throughout all climate zones, implying that the weather is not a decisive factor, although important, for the actual energy consumption of an individual building. On the building size via EUI, analysis disclosed that smaller buildings have a tendency to achieving lower energy use. Even so, the correlation is not absolute since some large buildings demonstrated low energy use while some small buildings performed opposite. Concerning the technologies, statistics indicated that the application of some technologies had correlations with some specific building size and climate characteristic. However, it was still hard to pinpoint a set of technologies which was directly correlative with a group of low EUI buildings.

It is concluded that no a single factor essentially determines the actual energy performance of HPBs. To deliver energy-efficient buildings, an integrated design taking account of climate, technology, occupant behavior as well as operation and maintenance should be implemented.

}, url = {https://www.techstreet.com/ashrae/standards/se-14-c033-revisit-of-energy-use-and-technologies-of-high-performance-buildings}, author = {Cheng Li and Tianzhen Hong} } @article {59964, title = {Stochastic Modeling of Overtime Occupancy and Its Application in Building Energy Simulation and Calibration}, year = {2014}, abstract = {

Overtime is a common phenomenon around the world. Overtime drives both internal heat gains from occupants, lighting and plug-loads, and HVAC operation during overtime periods. Overtime leads to longer occupancy hours and extended operation of building services systems beyond normal working hours, thus overtime impacts total building energy use. Current literature lacks methods to model overtime occupancy because overtime is stochastic in nature and varies by individual occupants and by time. To address this gap in the literature, this study aims to develop a new stochastic model based on the statistical analysis of measured overtime occupancy data from an office building. A binomial distribution is used to represent the total number of occupants working overtime, while an exponential distribution is used to represent the duration of overtime periods. The overtime model is used to generate overtime occupancy schedules as an input to the energy model of a second office building. The measured and simulated cooling energy use during the overtime period is compared in order to validate the overtime model. A hybrid approach to energy model calibration is proposed and tested, which combines ASHRAE Guideline 14 for the calibration of the energy model during normal working hours, and a proposed KS test for the calibration of the energy model during overtime. The developed stochastic overtime model and the hybrid calibration approach can be used in building energy simulations to improve the accuracy of results, and better understand the characteristics of overtime in office buildings.

}, keywords = {building energy use, building simulation, model calibration, occupant behavior, overtime occupancy, stochastic modeling}, author = {Kaiyu Sun and Tianzhen Hong and Siyue Guo} } @article {59963, title = {A Technical Framework to Describe Occupant Behavior for Building Energy Simulations}, year = {2014}, abstract = {

Green buildings that fail to meet expected design performance criteria indicate that technology alone does not guarantee high performance. Human influences are quite often simplified and ignored in the design, construction, and operation of buildings. Energy-conscious human behavior has been demonstrated to be a significant positive factor for improving the indoor environment while reducing the energy use of buildings. In our study we developed a new technical framework to describe energy-related human behavior in buildings. The energy-related behavior includes accounting for individuals and groups of occupants and their interactions with building energy services systems, appliances and facilities. The technical framework consists of four key components:

  1. the drivers behind energy-related occupant behavior, which are biological, societal, environmental, physical, and economical in nature
  2. the needs of the occupants are based on satisfying criteria that are either physical (e.g. thermal, visual and acoustic comfort) or non-physical (e.g. entertainment, privacy, and social reward)
  3. the actions that building occupants perform when their needs are not fulfilled
  4. the systems with which an occupant can interact to satisfy their needs

The technical framework aims to provide a standardized description of a complete set of human energy-related behaviors in the form of an XML schema. For each type of behavior (e.g., occupants opening/closing windows, switching on/off lights etc.) we identify a set of common behaviors based on a literature review, survey data, and our own field study and analysis. Stochastic models are adopted or developed for each type of behavior to enable the evaluation of the impact of human behavior on energy use in buildings, during either the design or operation phase. We will also demonstrate the use of the technical framework in assessing the impact of occupancy behavior on energy saving technologies. The technical framework presented is part of our human behavior research, a 5-year program under the U.S. - China Clean Energy Research Center for Building Energy Efficiency.

}, keywords = {building simulation, energy efficiency, framework, occupant behavior, XML schema}, author = {William J. N. Turner and Tianzhen Hong} } @article {56246, title = {Building energy modeling programs comparison Research on HVAC systems simulation part}, year = {2013}, abstract = {

Building energy simulation programs are effective tools for the evaluation of building energy saving and optimization of design. The fact that large discrepancies exist in simulated results when different BEMPs are used to model the same building has caused wide concern. Urgent research is needed to identify the main elements that contribute towards the simulation results. This technical report summarizes methodologies, processes, and the main assumptions of three building energy modeling programs (BEMPs) for HVAC calculations: EnergyPlus, DeST, and DOE-2.1E, and test cases are designed to analyze the calculation process in detail. This will help users to get a better understanding of BEMPs and the research methodology of building simulation. This will also help build a foundation for building energy code development and energy labeling programs.

}, keywords = {Building energy modeling programs, comparison tests, HVAC system simulation, theory analysis}, author = {Xin Zhou and Da Yan and Tianzhen Hong and Dandan Zhu} } @article {59968, title = {Building Energy Monitoring and Analysis}, year = {2013}, month = {06/2013}, abstract = {

U.S. and China are the world{\textquoteright}s top two economics. Together they consumed one-third of the world{\textquoteright}s primary energy. It is an unprecedented opportunity and challenge for governments, researchers and industries in both countries to join together to address energy issues and global climate change. Such joint collaboration has huge potential in creating new jobs in energy technologies and services.

Buildings in the US and China consumed about 40\% and 25\% of the primary energy in both countries in 2010 respectively. Worldwide, the building sector is the largest contributor to the greenhouse gas emission. Better understanding and improving the energy performance of buildings is a critical step towards sustainable development and mitigation of global climate change.

This project aimed to develop a standard methodology for building energy data definition, collection, presentation, and analysis; apply the developed methods to a standardized energy monitoring platform, including hardware and software, to collect and analyze building energy use data; and compile offline statistical data and online real-time data in both countries for fully understanding the current status of building energy use. This helps decode the driving forces behind the discrepancy of building energy use between the two countries; identify gaps and deficiencies of current building energy monitoring, data collection, and analysis; and create knowledge and tools to collect and analyze good building energy data to provide valuable and actionable information for key stakeholders.

Key research findings were summarized as follows:

The research outputs from the project can help better understand energy performance of buildings, improve building operations to reduce energy waste and increase efficiency, identify retrofit opportunities for existing buildings, and provide guideline to improve the design of new buildings. The standardized energy monitoring and analysis platform as well as the collected real building data can also be used for other CERC projects that need building energy measurements, and be further linked to building energy benchmarking and rating/labeling systems.

}, author = {Tianzhen Hong and Wei Feng and Alison Lu and Jianjun Xia and Le Yang and Qi Shen and Piljae Im and Mahabir Bhandari} } @article {57084, title = {Comparison of Building Energy Modeling Programs: HVAC Systems}, year = {2013}, month = {08/2013}, author = {Xin Zhou and Tianzhen Hong and Da Yan} } @article {56249, title = {Data Analysis and Modeling of Lighting Energy Use in Large Office Buildings}, year = {2013}, abstract = {

Lighting consumes about 20 to 40\% of total electricity use in large office buildings in the U.S. and China. In order to develop better lighting simulation models it is crucial to understand the characteristics of lighting energy use. This paper analyzes the main characteristics of lighting energy use over various time scales, based on the statistical analysis of measured lighting energy use of 17 large office buildings in Beijing and Hong Kong. It was found that the daily 24-hour variations of lighting energy use were mainly driven by the schedule of the building occupants. Outdoor illumination levels have little impact on lighting energy use in large office buildings due to the lack of automatic daylighting controls and relatively small perimeter areas. A stochastic lighting energy use model was developed based on different occupant activities during six time periods throughout a day, and the annual distribution of lighting power across those periods. The model was verified using measured lighting energy use of one selected building. This study demonstrates how statistical analysis and stochastic modeling can be applied to lighting energy use. The developed lighting model can be adopted by building energy modeling programs to improve the simulation accuracy of lighting energy use.

}, keywords = {building simulation, energy use, lighting, modeling, occupant behavior, office buildings, Poisson distribution}, author = {Xin Zhou and Da Yan and Xiaoxin Ren and Tianzhen Hong} } @article {56245, title = {A Detailed Loads Comparison of Three Building Energy Modeling Programs: EnergyPlus, DeST and DOE-2.1E}, journal = {Building Simulation}, volume = {6}, year = {2013}, month = {09/2013}, pages = {323-335}, publisher = {Tsinghua University Press}, chapter = {323}, abstract = {

Building energy simulation is widely used to help design energy efficient building envelopes and HVAC systems, develop and demonstrate compliance of building energy codes, and implement building energy rating programs. However, large discrepancies exist between simulation results from different building energy modeling programs (BEMPs). This leads many users and stakeholders to lack confidence in the results from BEMPs and building simulation methods. This paper compared the building thermal load modeling capabilities and simulation results of three BEMPs: EnergyPlus, DeST and DOE-2.1E. Test cases, based upon the ASHRAE Standard 140 tests, were designed to isolate and evaluate the key influencing factors responsible for the discrepancies in results between EnergyPlus and DeST. This included the load algorithms and some of the default input parameters. It was concluded that there is little difference between the results from EnergyPlus and DeST if the input values are the same or equivalent despite there being many discrepancies between the heat balance algorithms. DOE-2.1E can produce large errors for cases when adjacent zones have very different conditions, or if a zone is conditioned part-time while adjacent zones are unconditioned. This was due to the lack of a strict zonal heat balance routine in DOE-2.1E, and the steady state handling of heat flow through interior walls and partitions. This comparison study did not produce another test suite, but rather a methodology to design tests that can be used to identify and isolate key influencing factors that drive the building thermal loads, and a process with which to carry them out.

}, keywords = {building energy modeling program, building thermal loads, comparison, dest, DOE-2.1E, energyplus}, issn = {Print: 1996-3599; Online 1996-8744}, doi = {10.1007/s12273-013-0126-7}, author = {Dandan Zhu and Tianzhen Hong and Da Yan and Chuang Wang} } @article {56236, title = {A Fresh Look at Weather Impact on Peak Electricity Demand and Energy Use of Buildings Using 30-Year Actual Weather Data}, journal = {Applied Energy}, volume = {111}, year = {2013}, month = {11/2013}, pages = {333-350}, publisher = {Lawrence Berkeley National Laboratory}, abstract = {

Buildings consume more than one third of the world{\textquoteright}s total primary energy. Weather plays a unique and significant role as it directly affects the thermal loads and thus energy performance of buildings. The traditional simulated energy performance using Typical Meteorological Year (TMY) weather data represents the building performance for a typical year, but not necessarily the average or typical long-term performance as buildings with different energy systems and designs respond differently to weather changes. Furthermore, the single-year TMY simulations do not provide a range of results that capture yearly variations due to changing weather, which is important for building energy management, and for performing risk assessments of energy efficiency investments. This paper employs large-scale building simulation (a total of 3162 runs) to study the weather impact on peak electricity demand and energy use with the 30-year (1980{\textendash}2009) Actual Meteorological Year (AMY) weather data for three types of office buildings at two design efficiency levels, across all 17 ASHRAE climate zones. The simulated results using the AMY data are compared to those from the TMY3 data to determine and analyze the differences. Besides further demonstration, as done by other studies, that actual weather has a significant impact on both the peak electricity demand and energy use of buildings, the main findings from the current study include: (1) annual weather variation has a greater impact on the peak electricity demand than it does on energy use in buildings; (2) the simulated energy use using the TMY3 weather data is not necessarily representative of the average energy use over a long period, and the TMY3 results can be significantly higher or lower than those from the AMY data; (3) the weather impact is greater for buildings in colder climates than warmer climates; (4) the weather impact on the medium-sized office building was the greatest, followed by the large office and then the small office; and (5) simulated energy savings and peak demand reduction by energy conservation measures using the TMY3 weather data can be significantly underestimated or overestimated. It is crucial to run multi-decade simulations with AMY weather data to fully assess the impact of weather on the long-term performance of buildings, and to evaluate the energy savings potential of energy conservation measures for new and existing buildings from a life cycle perspective.

}, keywords = {Actual meteorological year, building simulation, energy use, Peak electricity demand, Typical meteorological year, weather data}, doi = {10.1016/j.apenergy.2013.05.019}, author = {Tianzhen Hong and Wen-Kuei Chang and Hung-Wen Lin} } @article {3449, title = {Statistical Analysis and Modeling of Occupancy Patterns in Open-Plan Offices using Measured Lighting-Switch Data}, journal = {Building Simulation}, volume = {6}, year = {2013}, month = {03/2013}, pages = {23{\textendash}32}, abstract = {

Occupancy profile is one of the driving factors behind discrepancies between the measured and simulated energy consumption of buildings. The frequencies of occupants leaving their offices and the corresponding durations of absences have significant impact on energy use and the operational controls of buildings. This study used statistical methods to analyze the occupancy status, based on measured lighting-switch data in five-minute intervals, for a total of 200 open-plan (cubicle) offices. Five typical occupancy patterns were identified based on the average daily 24-hour profiles of the presence of occupants in their cubicles. These statistical patterns were represented by a one-square curve, a one-valley curve, a two-valley curve, a variable curve, and a flat curve. The key parameters that define the occupancy model are the average occupancy profile together with probability distributions of absence duration, and the number of times an occupant is absent from the cubicle. The statistical results also reveal that the number of absence occurrences decreases as total daily presence hours decrease, and the duration of absence from the cubicle decreases as the frequency of absence increases. The developed occupancy model captures the stochastic nature of occupants moving in and out of cubicles, and can be used to generate a more realistic occupancy schedule. This is crucial for improving the evaluation of the energy saving potential of occupancy based technologies and controls using building simulations. Finally, to demonstrate the use of the occupancy model, weekday occupant schedules were generated and discussed.

}, keywords = {building simulation, occupancy model, occupancy pattern, occupant schedule, office buildings, statistical analysis}, issn = {1996-8744}, doi = {10.1007/s12273-013-0106-y}, author = {Wen-Kuei Chang and Tianzhen Hong} } @article {56946, title = {The Two-Day CERC-BEE Forum on Building Integrated Design and Occupant Behavior: Presentations and Summary}, year = {2013}, author = {Tianzhen Hong and William J. N. Turner and Cheng Li} } @conference {57409, title = {Application of a stochastic window use model in EnergyPlus}, booktitle = {SimBuild 2012, 5th National Conference of IBPSA-USA, August 1-3, 2012}, year = {2012}, month = {08/2012}, address = {Madison, WI}, abstract = {

Natural ventilation, used appropriately, has the potential to provide both significant HVAC energy savings, and improvements in occupant satisfaction.

Central to the development of natural ventilation models is the need to accurately represent the behavior of building occupants. The work covered in this paper describes a method of implementing a stochastic window model in EnergyPlus. Simulated window use data from three stochastic window opening models was then compared to measured window opening behavior, collected in a naturally-ventilated office in California. Recommendations regarding the selection of stochastic window use models, and their implementation in EnergyPlus, are presented.

}, url = {https://escholarship.org/uc/item/2gm7r783}, author = {Spencer M. Dutton and Hui Zhang and Yongchao Zhai and Edward A. Arens and Youness Bennani Smires and Samuel L. Brunswick and Kyle S. Konis and Philip Haves} } @conference {2673, title = {Comparative research in building energy modeling programs}, booktitle = {China Annual HVACR Conference}, year = {2012}, month = {06/2011}, address = {China (in Chinese)}, keywords = {advanced building software: energyplus, building energy modeling program, building simulation, comparison, dest, doe-2, energyplus, simulation research group, test}, author = {Dandan Zhu and Tianzhen Hong and Da Yan and Chuang Wang} } @article {3445, title = {Comparison of Building Energy Modeling Programs: Building Loads}, year = {2012}, month = {06/2012}, author = {Dandan Zhu and Tianzhen Hong and Chuang Wang} } @conference {3444, title = {The Energy Saving Potential of Membrane-Based Enthalpy Recovery in Vav Systems for Commercial Office Buildings}, booktitle = {SimBuild 2012 IBPSA Conference}, year = {2012}, abstract = {

A design tool to evaluate the heat and mass transfer effectiveness and pressure drop of a membrane-based enthalpy exchanger was developed and then used to optimize the configuration of an enthalpy exchanger for minimum pressure drop and maximum heat recovery effectiveness. Simulation was used in a parametric study to investigate the energy saving potential of the enthalpy recovery system. The case without energy recovery and air side economizer was used as a baseline. Two comparison cases for the implementation of enthalpy recovery with and without air side economizer were simulated in EnergyPlus. A case using a desiccant wheel for energy recovery was also investigated for comparison purposes. The simulation results show significant energy saving benefits from applying a low pressure drop, high effectiveness enthalpy exchanger in two US cities representing a range of humid climates. The sensitivity of the energy savings potential to pressure drop and heat and mass transfer effectivenesses is also presented.

}, author = {Liping Wang and Philip Haves and John Breshears} } @conference {3407, title = {The Energy Saving Potential of Membrane-Based Enthalpy Recovery in VAV System for Commercial Office Buildings}, booktitle = {SimBuild 2012}, year = {2012}, month = {08/2012}, address = {Madison, Wisconsin}, author = {Liping Wang and Philip Haves and John Breshears} } @article {2591, title = {A framework for simulation-based real-time whole building performance assessment}, journal = {Building and Environment}, volume = {54}, year = {2012}, month = {08/2012}, pages = {100-108}, chapter = {100}, abstract = {

Most commercial buildings do not perform as well in practice as intended by the design and their performances often deteriorate over time. Reasons include faulty construction, malfunctioning equipment, incorrectly configured control systems and inappropriate operating procedures. One approach to addressing this problems is to compare the predictions of an energy simulation model of the building to the measured performance and analyze significant differences to infer the presence and location of faults. This paper presents a framework that allows a comparison of building actual performance and expected performance in real time. The realization of the framework utilized the EnergyPlus, the Building Controls Virtual Test Bed (BCVTB) and the Energy Management and Control System (EMCS) was developed. An EnergyPlus model that represents expected performance of a building runs in real time and reports the predicted building performance at each time step. The BCVTB is used as the software platform to acquire relevant inputs from the EMCS through a BACnet interface and send them to the EnergyPlus and to a database for archiving. A proof-of-concept demonstration is also presented.

}, keywords = {building controls virtual test bed, building performance, energy modeling, energyplus, real-time building simulation}, issn = {0360-1323}, author = {Xiufeng Pang and Michael Wetter and Prajesh Bhattacharya and Philip Haves} } @conference {3442, title = {An Improved Simple Chilled Water Cooling Coil Model}, booktitle = {SimBuild 2012 IBPSA Conference}, year = {2012}, month = {08/2012}, abstract = {

The accurate prediction of cooling and dehumidification coil performance is important in model-based fault detection and in the prediction of HVAC system energy consumption for support of both design and operations. It is frequently desirable to use a simple cooling coil model that does not require detailed specification of coil geometry and material properties. The approach adopted is to match the overall UA of the coil to the rating conditions and to estimate the air-side and water-side components of the UA using correlations developed by Holmes (1982). This approach requires some geometrical information about the coil and the paper investigates the sensitivity of the overall performance prediction to uncertainties in this information, including assuming a fixed ratio of air-side to water-side UA at the rating condition. Finally, simulation results from different coil models are compared, and experimental data are used to validate the improved cooling coil model.

}, author = {Liping Wang and Philip Haves and Walter F. Buhl} } @conference {2670, title = {An In-Depth Analysis of Space Heating Energy Use in Office Buildings}, booktitle = {ACEEE 2012 Summer Study}, year = {2012}, month = {08/2012}, publisher = {ACEEE}, organization = {ACEEE}, address = {Asilomar, CA}, abstract = {

Space heating represents the largest end use in the U.S. buildings and consumes more than 7 trillion Joules of site energy annually [USDOE]. Analyzing building space heating performance and identifying methods for saving energy are quite important. Hence, it is crucial to identify and evaluate key driving factors to space heating energy use to support the design and operation of low energy buildings.

In this study, the prototypical small and large-size office buildings of the USDOE commercial reference buildings, which comply with ASHRAE Standard 90.1-2004, are selected. Key design and operation factors were identified to evaluate their degrees of impact for space heating energy use. Simulation results demonstrate that some of the selected building design and operation parameters have more significant impacts on space heating energy use than others, on the other hand, good operation practice can save more space heating energy than raising design efficiency levels of an office building. Influence of weather data used in simulations on space heating energy is found to be significant. The simulated space heating energy use is further benchmarked against those from similar office buildings in two U.S. commercial buildings databases to better understand the discrepancies.

Simulated results from this study and space heating energy use collected from building databases can both vary in two potentially well overlapped wide ranges depending on details of building design and operation, not necessarily that simulation always under-predicts the reality.

}, keywords = {building energy performance, building simulation, simulation research, simulation research group, space heating}, author = {Hung-Wen Lin and Tianzhen Hong} } @conference {3180, title = {Mapping Hvac Systems for Simulation In EnergyPlus}, booktitle = {SimBuild 2012 IBPSA Conference}, year = {2012}, month = {07/2012}, address = {Madison, WI, USA}, abstract = {

For building energy simulation tools to be accessible to designers, tool interfaces should present a conventional view of HVAC systems to the user, and then map this view to the internal data model used in the tool. The paper outlines a process that enables design engineers to create HVAC system representations using industry standard terminology and system, icon and typological representations and convert that unified representation into the format required by the whole building energy simulation tool EnergyPlus. This paper describes each stage of the conversion process, which involves transformations between the following representations: 1) engineer{\textquoteright}s representation, 2) component connectivity representation, 3) representation in the internal data model used in the Simergy graphical user interface for EnergyPlus, and 4) EnergyPlus representation.

The paper also describes mappings between these representations and the development of a rule-based validation and assignment framework required to implement that mapping. In addition, the paper describes the implementation of this process in Simergy.

}, author = {Tobias Maile and Mangesh Basarkar and James O{\textquoteright}Donnell and Philip Haves and Kevin Settlemyre} } @article {3414, title = {Monitoring-based HVAC Commissioning of an Existing Office Building for Energy Efficiency}, year = {2012}, month = {10/2012}, abstract = {

The performance of Heating, Ventilation and Air Conditioning (HVAC) systems may fail to satisfy design expectations due to improper equipment installation, equipment degradation, sensor failures, or incorrect control sequences. Commissioning identifies and implements cost-effective operational and maintenance measures in buildings to bring them up to the design intent or optimum operation. An existing office building is used as a case study to demonstrate the process of commissioning. Building energy benchmarking tools are applied to evaluate the energy performance for screening opportunities at the whole building level. A large natural gas saving potential was indicated by the building benchmarking results. Faulty operations in the HVAC systems, such as improper operations of air-side economizers, simultaneous heating and cooling, and ineffective optimal start, were identified through trend data analyses and functional testing. The energy saving potential for each commissioning measure is quantified with a calibrated building simulation model. An actual energy saving of 10\% was realized after the implementations of cost-effective measures.

}, keywords = {benchmarking, commissioning, energyplus, fault detection and diagnostics, functional testing, trend data}, author = {Shankar Earni and Spencer Woodworth and Xiufeng Pang and Jorge Hernandez-Maldonado and Rongxin Yin and Liping Wang and Steve E. Greenberg and John Fiegel and Alma Rubalcava} } @conference {2671, title = {A Retrofit Tool for Improving Energy Efficiency of Commercial Buildings}, booktitle = {ACEEE 2012 Summer Study}, year = {2012}, month = {08/2012}, address = {Asilomar, CA}, abstract = {

Existing buildings will dominate energy use in commercial buildings in the United States for three decades or longer and even in China for the about two decades. Retrofitting these buildings to improve energy efficiency and reduce energy use is thus critical to achieving the target of reducing energy use in the buildings sector. However there are few evaluation tools that can quickly identify and evaluate energy savings and cost effectiveness of energy conservation measures (ECMs) for retrofits, especially for buildings in China. This paper discusses methods used to develop such a tool and demonstrates an application of the tool for a retrofit analysis. The tool builds on a building performance database with pre-calculated energy consumption of ECMs for selected commercial prototype buildings using the EnergyPlus program. The tool allows users to evaluate individual ECMs or a package of ECMs. It covers building envelope, lighting and daylighting, HVAC, plug loads, service hot water, and renewable energy. The prototype building can be customized to represent an actual building with some limitations. Energy consumption from utility bills can be entered into the tool to compare and calibrate the energy use of the prototype building. The tool currently can evaluate energy savings and payback of ECMs for shopping malls in China. We have used the tool to assess energy and cost savings for retrofit of the prototype shopping mall in Shanghai. Future work on the tool will simplify its use and expand it to cover other commercial building types and other countries.\ 

}, keywords = {building simulation, buildings, China, commercial building, energy efficiency measures, retrofit tool, simulation research group}, url = {http://aceee.org/files/proceedings/2012/data/papers/0193-000098.pdf$\#$page=1}, author = {Mark D. Levine and Wei Feng and Jing Ke and Tianzhen Hong and Nan Zhou} } @article {3181, title = {BacNet and Analog/Digital Interfaces of the Building Controls Virtual Testbed}, year = {2011}, month = {11/2011}, abstract = {

This paper gives an overview of recent developments in the Building Controls Virtual Test Bed (BCVTB), a framework for co-simulation and hardware-in-the-loop.

First, a general overview of the BCVTB is presented. Second, we describe the BACnet interface, a link which has been implemented to couple BACnet devices to the BCVTB. We present a case study where the interface was used to couple a whole building simulation program to a building control system to assess in real-time the performance of a real building. Third, we present the ADInterfaceMCC, an analog/digital interface that allows a USB-based analog/digital converter to be linked to the BCVTB. In a case study, we show how the link was used to couple the analog/digital converter to a building simulation model for local loop control.

}, author = {Philip Haves and Prajesh Bhattacharya and Thierry Stephane Nouidui and Michael Wetter and Zhengwei Li and Xiufeng Pang} } @proceedings {2785, title = {BACnet and Analog/Digital Interfaces of the Building Controls Virtual Test Bed}, journal = {Proc. of the 12th IBPSA Conference}, year = {2011}, month = {11/2011}, pages = {p. 294-301}, address = {Sydney, Australia}, author = {Thierry Stephane Nouidui and Michael Wetter and Zhengwei Li and Xiufeng Pang and Prajesh Bhattacharya and Philip Haves} } @conference {3404, title = {A Comparison of DeST and EnergyPlus}, booktitle = {China HVAC Simulation Conference}, year = {2011}, month = {2011}, address = {Beijing}, keywords = {building simulation, comparison, dest, energy modeling, energyplus, simulation research, simulation research group, test cases}, author = {Dandan Zhu and Chuang Wang and Da Yan and Tianzhen Hong} } @conference {2633, title = {Development of a user interface for the EnergyPlus whole building energy simulation program}, booktitle = {IBPSA Building Simulation 2011}, year = {2011}, month = {11/2011}, address = {Sydney, Australia}, author = {Richard See and Philip Haves and Pramod Sreekanathan and Mangesh Basarkar and James O{\textquoteright}Donnell and Kevin Settlemyre} } @conference {2672, title = {Modeling and simulation of HVAC faults in EnergyPlus}, booktitle = {Building Simulation 2011}, year = {2011}, month = {11/2011}, address = {Australia}, keywords = {advanced building software: energyplus, building simulation, energyplus, faults, fouling, modeling, sensor offset, simulation research group}, author = {Mangesh Basarkar and Philip Haves and Xiufeng Pang and Liping Wang and Tianzhen Hong} } @article {3179, title = {Modeling and simulation of HVAC Results in EnergyPlus}, year = {2011}, month = {11/2011}, author = {Mangesh Basarkar and Xiufeng Pang and Liping Wang and Tianzhen Hong} } @proceedings {2787, title = {Real-time Building Energy Simulation using EnergyPlus and the Building Controls Virtual Test Bed}, journal = {Proc. of the 12th IBPSA Conference}, year = {2011}, month = {11/2011}, pages = {p. 2890-2896}, address = {Sydney, Australia}, abstract = {

Most commercial buildings do not perform as well in practice as intended by the design and their performances often deteriorate over time. Reasons include faulty construction, malfunctioning equipment, incorrectly configured control systems and inappropriate operating procedures (Haves et al., 2001, Lee et al., 2007). To address this problem, the paper presents a simulation-based whole building performance monitoring tool that allows a comparison of building actual performance and expected performance in real time. The tool continuously acquires relevant building model input variables from existing Energy Management and Control System (EMCS). It then reports expected energy consumption as simulated of EnergyPlus. The Building Control Virtual Test Bed (BCVTB) is used as the software platform to provide data linkage between the EMCS, an EnergyPlus model, and a database. This paper describes the integrated real-time simulation environment. A proof-of-concept demonstration is also presented in the paper.

}, author = {Xiufeng Pang and Prajesh Bhattacharya and Zheng O{\textquoteright}Neill and Philip Haves and Michael Wetter and Trevor Bailey} } @conference {2630, title = {SimModel: A domain data model for whole building energy simulation}, booktitle = {IBPSA Building Simulation 2011}, year = {2011}, month = {10/2011}, abstract = {

Many inadequacies exist within industry-standard data models as used by present-day whole-building energy simulation software. Tools such as EnergyPlus and DOE-2 use custom schema definitions (IDD and BDL respectively) as opposed to standardized schema definitions (defined in XSD, EXPRESS, etc.). Non-standard data modes lead to a requirement for application developers to develop bespoke interfaces. Such tools have proven to be error prone in their implementation {\textendash} typically resulting in information loss.

This paper presents a Simulation Domain Model (SimModel) - a new interoperable XML-based data model for the building simulation domain. SimModel provides a consistent data model across all aspects of the building simulation process, thus preventing information loss. The model accounts for new simulation tool architectures, existing and future systems, components and features. In addition, it is a multi-representation model that enables integrated geometric and MEP simulation configuration data. The SimModel objects ontology moves away from tool-specific, non-standard nomenclature by implementing an industry-validated terminology aligned with Industry Foundation Classes (IFC).

The first implementation of SimModel supports translations from IDD, Open Studio IDD, gbXML and IFC. In addition, the EnergyPlus Graphic User Interface (GUI) employs SimModel as its internal data model. Ultimately, SimModel will form the basis for a new IFC Model View Definition (MVD) that will enable data exchange from HVAC Design applications to Energy Analysis applications. Extensions to SimModel could easily support other data formats and simulations (e.g. Radiance, COMFEN, etc.).

}, author = {James O{\textquoteright}Donnell and Richard See and Cody Rose and Tobias Maile and Vladimir Bazjanac and Philip Haves} } @conference {418, title = {Assessment of Energy Impact of Window Technologies for Commercial Buildings}, booktitle = {2010 ACEEE Summer Study}, year = {2010}, month = {2010}, keywords = {building energy performance, energyplus, shading controls, simulation, windows}, author = {Tianzhen Hong and Stephen E. Selkowitz} } @article {1843, title = {Assessment of Energy Savings Potential from the Use of Demand Control Ventilation Systems in General Office Spaces in California}, journal = {Building Simulation}, volume = {3}, year = {2010}, month = {06/2010}, pages = {117-124}, publisher = {Lawrence Berkeley National Laboratory}, type = {Research Article}, address = {Berkeley}, abstract = {

Demand controlled ventilation (DCV) was evaluated for general office spaces in California. A medium size office building meeting the prescriptive requirements of the 2008 California building energy efficiency standards (CEC 2008) was assumed in the building energy simulations performed with the EnergyPlus program to calculate the DCV energy savings potential in five typical California climates. Three design occupancy densities and two minimum ventilation rates were used as model inputs to cover a broader range of design variations. The assumed values of minimum ventilation rates in offices without DCV, based on two different measurement methods, were 81 and 28 cfm per occupant. These rates are based on the co-author{\textquoteright}s unpublished analyses of data from EPA{\textquoteright}s survey of 100 U.S. office buildings. These minimum ventilation rates exceed the 15 to 20 cfm per person required in most ventilation standards for offices. The cost effectiveness of applying DCV in general office spaces was estimated via a life cycle cost analyses that considered system costs and energy cost reductions.

The results of the energy modeling indicate that the energy savings potential of DCV is largest in the desert area of California (climate zone 14), followed by Mountains (climate zone 16), Central Valley (climate zone 12), North Coast (climate zone 3), and South Coast (climate zone 6).

The results of the life cycle cost analysis show DCV is cost effective for office spaces if the typical minimum ventilation rates without DCV is 81 cfm per person, except at the low design occupancy of 10 people per 1000 ft2 in climate zones 3 and 6. At the low design occupancy of 10 people per 1000 ft2, the greatest DCV life cycle cost savings is a net present value (NPV) of $0.52/ft2 in climate zone 14, followed by $0.32/ft2 in climate zone 16 and $0.19/ft2 in climate zone 12. At the medium design occupancy of 15 people per 1000 ft2, the DCV savings are higher with a NPV $0.93/ft2 in climate zone 14, followed by $0.55/ft2 in climate zone 16, $0.46/ft2 in climate zone 12, $0.30/ft2 in climate zone 3, $0.16/ft2 in climate zone 3. At the high design occupancy of 20 people per 1000 ft2, the DCV savings are even higher with a NPV $1.37/ft2 in climate zone 14, followed by $0.86/ft2 in climate zone 16, $0.84/ft2 in climate zone 3, $0.82/ft2 in climate zone 12, and $0.65/ft2 in climate zone 6.

DCV was not found to be cost effective if the typical minimum ventilation rate without DCV is 28 cfm per occupant, except at high design occupancy of 20 people per 1000 ft2 in climate zones 14 and 16.

Until the large uncertainties about the base case ventilation rates in offices without DCV are reduced, the case for requiring DCV in general office spaces will be a weak case.

}, keywords = {building simulation, california building energy standard, Commercial Building Ventilation and Indoor Environmental Quality Group, demand controlled ventilation, energy savings, indoor environment department, other}, doi = {10.1007/s12273-010-0001-8}, author = {Tianzhen Hong and William J. Fisk} } @proceedings {393, title = {Automated Continuous Commissioning of Commercial Buildings}, journal = {DoD SERDP-ESTCP Partners in Environmental Technology Technical Symposium and Workshop}, year = {2010}, month = {11/2010}, address = {Washington, D.C.}, author = {Trevor Bailey and Zheng O{\textquoteright}Neill and Madhusudana Shashanka and Prajesh Bhattacharya and Philip Haves and Xiufeng Pang} } @article {75, title = {Co-simulation for performance prediction of integrated building and HVAC systems - An analysis of solution characteristics using a two-body system}, journal = {Simulation Modelling Practice and Theory}, volume = {18}, year = {2010}, month = {08/2010}, pages = {957-970}, chapter = {957}, abstract = {

Integrated performance simulation of buildings and heating, ventilation and air-conditioning (HVAC) systems can help in reducing energy consumption and increasing occupant comfort. However, no single building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to analyze integrated building systems and to enable rapid prototyping of innovative building and system technologies. One way to alleviate this problem is to use co-simulation to integrate different BPS tools. Co-simulation approach represents a particular case of simulation scenario where at least two simulators solve coupled differential-algebraic systems of equations and exchange data that couples these equations during the time integration.

This article analyzes how co-simulation influences consistency, stability and accuracy of the numerical approximation to the solution. Consistency and zero-stability are studied for a general class of the problem, while a detailed consistency and absolute stability analysis is given for a simple two-body problem. Since the accuracy of the numerical approximation to the solution is reduced in co-simulation, the article concludes by discussing ways for how to improve accuracy.

}, doi = {10.1016/j.simpat.2010.02.011}, author = {Marija Trcka and Jan Hensen and Michael Wetter} } @conference {244, title = {Development and Testing of Model Predictive Control for a Campus Chilled Water Plant with Thermal Storage}, booktitle = {2010 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2010}, publisher = {Omnipress}, organization = {Omnipress}, address = {Asilomar, California, USA}, abstract = {

A Model Predictive Control (MPC) implementation was developed for a university campus chilled water plant. The plant includes three water-cooled chillers and a two million gallon chilled water storage tank. The tank is charged during the night to minimize on-peak electricity consumption and take advantage of the lower ambient wet bulb temperature. A detailed model of the chilled water plant and simplified models of the campus buildings were developed using the equation-based modeling language Modelica. Steady state models of the chillers, cooling towers and pumps were developed, based on manufacturers{\textquoteright} performance data, and calibrated using measured data collected and archived by the control system. A dynamic model of the chilled water storage tank was also developed and calibrated. A semi-empirical model was developed to predict the temperature and flow rate of the chilled water returning to the plant from the buildings. These models were then combined and simplified for use in a MPC algorithm that determines the optimal chiller start and stop times and set-points for the condenser water temperature and the chilled water supply temperature. The paper describes the development and testing of the MPC implementation and discusses lessons learned and next steps in further research.

}, issn = {0-918249-60-0}, author = {Brian E. Coffey and Philip Haves and Michael Wetter and Brandon Hencey and Francesco Borrelli and Yudong Ma and Sorin Bengea} } @proceedings {217, title = {Impact of time-splitting schemes on the accuracy of FFD simulations}, journal = {the 7th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2010)}, year = {2010}, pages = {55-60}, address = {Syracuse, NY}, author = {Jianjun Hu and Wangda Zuo and Qingyan Chen} } @article {211, title = {Improvements on FFD modeling by using different numerical schemes}, journal = {Numerical Heat Transfer, Part B Fundamentals}, volume = {58}, year = {2010}, pages = {1-16}, author = {Wangda Zuo and Jianjun Hu and Qingyan Chen} } @proceedings {241, title = {Model Predictive Control of Thermal Energy Storage in Building Cooling Systems}, journal = {American Control Conference}, year = {2010}, month = {06/2010}, address = {Baltimore, Maryland, USA}, abstract = {A model-based predictive control (MPC) is designed for optimal thermal energy storage in building cooling systems. We focus on buildings equipped with a water tank used for actively storing cold water produced by a series of chillers. Typically the chillers are operated at night to recharge the storage tank in order to meet the building demands on the following day. In this paper, we build on our previous work, improve the building load model, and present experimental results. The experiments show that MPC can achieve reductionin the central plant electricity cost and improvement of its efficiency.}, author = {Yudong Ma and Francesco Borrelli and Brandon Hencey and Brian E. Coffey and Sorin Bengea and Philip Haves} } @article {240, title = {Modeling and Measurement Constraints in Fault Diagnostics for HVAC Systems}, journal = {ASME Journal of Dynamic Systems, Measurement, and Controls}, year = {2010}, abstract = {Many studies have shown that energy savings of five to fifteen percent are achievable in commercial buildings by detecting and correcting building faults, and optimizing building control systems. However,in spite of good progress in developing tools for determining HVAC diagnostics, methods to detect faults in HVAC systems are still generally undeveloped. Most approaches use numerical filtering or parameter estimation methods to compare data from energy meters and building sensors to predictions from mathematical or statistical models. They are effective when models are relatively accurate and data contain few errors. In this paper, we address the case where models are imperfect and data are variable, uncertain, and can contain error. We apply a Bayesian updating approach that is systematic in managing and accounting for most forms of model and data errors. The proposed method uses both knowledge of first principle modeling and empirical results to analyze the system performance within the boundaries defined by practical constraints. We demonstrate the approach by detecting faults in commercial building air handling units. We find that the limitations that exist in air handling unit diagnostics due to practical constraints can generally be effectively addressed through the proposed approach.}, author = {Massieh Najafi and David M. Auslander and Peter L. Bartlett and Philip Haves and Michael D. Sohn} } @article {242, title = {A Statistical Pattern Analysis Framework for Rooftop Unit Diagnostics}, journal = {International Journal of Heating, Ventilating, Air-Conditioning and Refrigeration Research}, year = {2010}, author = {Massieh Najafi and David M. Auslander and Philip Haves and Michael D. Sohn} } @proceedings {243, title = {Systems Approach to Energy Efficient Building Operation: Case Studies and Lessons Learned in a University Campus}, journal = {2010 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2010}, publisher = {Omnipress}, address = {Asilomar, California, USA}, abstract = {

This paper reviews findings from research conducted at a university campus to develop a robust systems approach to monitor and continually optimize building energy performance. The field analysis, comprising three projects, included detailed monitoring, model-based analysis of system energy performance, and implementation of optimized control strategies for both district and building-scale systems. One project used models of the central cooling plant and campus building loads, and weather forecasts to analyze and optimize the energy performance of a district cooling system, comprising chillers, pumps and a thermal energy storage system. Fullscale implementation of policies devised with a model predictive control approach produced energy savings of about 5\%, while demonstrating that the heuristic policies implemented by the operators were close to optimal during peak cooling season and loads. Research was also conducted to evaluate whole building monitoring and control methods. A second project performed in a campus building combined sub-metered end-use data, performance benchmarks, energy simulations and thermal load estimators to create a web-based energy performance visualization tool prototype. This tool provides actionable energy usage information to aid in facility operation and to enable performance improvement. In a third project, an alternative to demand controlled ventilation enabled by direct measurements of building occupancy levels was assessed. Simulations were used to show 5-15\% reduction in building HVAC system energy usage when using estimates of actual occupancy levels.

}, isbn = {0-918249-60-0}, author = {Satish Narayanan and Michael G. Apte and Philip Haves and Mary Ann Piette and John Elliott} } @article {214, title = {Anisotropy invariant Reynolds stress model of turbulence (AIRSM) and its application on attached and separated wall-bounded flows}, journal = {Flow, Turbulence and Combustion}, volume = {83}, year = {2009}, month = {07/2009}, pages = {81-103}, chapter = {81}, abstract = {

Numerical predictions with a differential Reynolds stress closure, which in its original formulation explicitly takes into account possible states of turbulence on the anisotropy-invariant map, are presented. Thus the influence of anisotropy of turbulence on the modeled terms in the governing equations for the Reynolds stresses is accounted for directly. The anisotropy invariant Reynolds stress model (AIRSM) is implemented and validated in different finite-volume codes. The standard wall-function approach is employed as initial step in order to predict simple and complex wall-bounded flows undergoing large separation. Despite the use of simple wall functions, the model performed satisfactory in predicting these flows. The predictions of the AIRSM were also compared with existing Reynolds stress models and it was found that the present model results in improved convergence compared with other models. Numerical issues involved in the implementation and application of the model are also addressed.

}, keywords = {Anisotrpoy, Invariant map, Reynolds stress model, Reynolds-averaged Navier-Stokes, Separated wall-bounded flow, Turbulence, Turbulence modeling}, issn = {1573-1987}, doi = {10.1007/s10494-008-9190-y}, author = {V. Kumar and Bettina Frohnapfel and Jovan Jovanovi{\'c} and Michael Breuer and Wangda Zuo and Ibrahim Hadzi{\'c} and Richard Lechner} } @article {3446, title = {Assessment of Energy Impact of Window Technologies for Commercial Buildings}, year = {2009}, month = {10/2009}, author = {Tianzhen Hong and Stephen E. Selkowitz and Mehry Yazdanian} } @article {412, title = {A close look at the China design standard for energy efficiency of public buildings}, journal = {Energy and Buildings}, volume = {41}, year = {2009}, month = {2009}, pages = {426-435}, type = {Research Article}, abstract = {

This paper takes a close look at the China national standard GB50189-2005, Design Standard for Energy Efficiency of Public Buildings, which was enforced on July 1, 2005. The paper first reviews the standard, then compares the standard with ASHRAE Standard 90.1-2004 to identify discrepancies in code coverage and stringency, and recommends some energy conservation measures that can be evaluated in the design of public buildings to achieve energy savings beyond the standard. The paper also highlights several important features of 90.1-2004 that may be considered as additions to the GB50189-2005 standard during the next revision. At the end the paper summarizes the latest developments in building energy standards and rating systems in China and the US.

}, keywords = {ASHRAE 90.1, building energy standard, China, commercial buildings, energy efficiency, gb50189-2005}, doi = {10.1016/j.enbuild.2008.11.003}, author = {Tianzhen Hong} } @article {408, title = {Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems}, journal = {Energy and Buildings}, volume = {42}, year = {2009}, month = {2009}, pages = {584-589}, type = {Research Article}, abstract = {

With the current movement towards net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a preliminary comparison of energy efficiency between the air-source VRF and GSHP systems is presented. The computer simulation results show that GSHP system is more energy efficient than the air-source VRF system for conditioning a small office building in two selected US climates. In general, GSHP system is more energy efficient than the air-source VRV system, especially when the building has significant heating loads. For buildings with less heating loads, the GSHP system could still perform better than the air-source VRF system in terms of energy efficiency, but the resulting energy savings may be marginal.

}, keywords = {building simulation, doe-2, energy efficiency, gshp, vrf}, doi = {10.1016/j.enbuild.2009.10.028}, author = {Xiaobing Liu and Tianzhen Hong} } @article {68, title = {Co-simulation of innovative integrated HVAC systems in buildings}, journal = {Journal of Building Performance Simulation}, volume = {2}, year = {2009}, pages = {209-230}, chapter = {209}, abstract = {

Integrated performance simulation of buildings HVAC systems can help in reducing energy consumption and increasing occupant comfort. However, no single building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to analyze integrated building systems and to enable rapid prototyping of innovative building and system technologies. One way to alleviate this problem is to use co-simulation, as an integrated approach to simulation. This article elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in the here described co-simulation prototype. The prototype is validated with the results obtained from the traditional simulation approach. It is further used in a proof-of-concept case study to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling time step.

}, keywords = {building performance simulation, co-simulation, hvac simulation, innovative building system modelling and simulation}, doi = {10.1080/19401490903051959}, url = {http://www.informaworld.com/smpp/section?content=a913244253\&fulltext=713240928}, author = {Marija Trcka and Jan Hensen and Michael Wetter} } @proceedings {60, title = {An implementation of co-simulation for performance prediction of innovative integrated HVAC systems in buildings}, journal = {Proc. of the 11th IBPSA Conference}, year = {2009}, month = {07/2009}, pages = {724-731}, address = {Glasgow, Scotland}, abstract = {Integrated performance simulation of buildings and heating, ventilation and air-conditioning (HVAC)systems can help reducing energy consumption and increasing level of occupant comfort. However, no singe building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to accommodate the ever-increasing complexity and rapid innovations in building and system technologies. One way to alleviate this problem is to use co-simulation. The co-simulation approach represents a particular case of simulation scenario where at least two simulators solve coupled differential-algebraic systems of equations and exchange data that couples these equations during the time integration. This paper elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in a co-simulation prototype. The prototype is verified and validated against the results obtained from the traditional simulation approach. It is further used in a case study for the proof-of-concept, to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling frequency. The paper concludes by defining requirements and recommendations for generic co-simulation implementations.}, url = {http://www.ibpsa.org/proceedings/BS2009/BS09_0724_731.pdf}, author = {Marija Trcka and Michael Wetter and Jan Hensen} } @article {409, title = {Simulation-based assessment of the energy savings benefits of integrated control in office buildings}, journal = {Building Simulation}, volume = {2}, year = {2009}, month = {2009}, pages = {239-251}, type = {Research Article}, abstract = {

The purpose of this study is to use existing simulation tools to quantify the energy savings benefits of integrated control in office buildings. An EnergyPlus medium office benchmark simulation model (V1.0_3.0) developed by the Department of Energy (DOE) was used as a baseline model for this study. The baseline model was modified to examine the energy savings benefits of three possible control strategies compared to a benchmark case across 16 DOE climate zones. Two controllable subsystems were examined: (1) dimming of electric lighting, and (2) controllable window transmission. Simulation cases were run in EnergyPlus V3.0.0 for building window-to-wall ratios (WWR) of 33\% and 66\%. All three strategies employed electric lighting dimming resulting in lighting energy savings in building perimeter zones ranging from 64\% to 84\%. Integrated control of electric lighting and window transmission resulted in heating, ventilation, and air conditioning (HVAC) energy savings ranging from {\textendash}1\% to 40\%. Control of electric lighting and window transmission with HVAC integration (seasonal schedule of window transmission control) resulted in HVAC energy savings ranging from 3\% to 43\%. HVAC energy savings decreased moving from warm climates to cold climates and increased when moving from humid, to dry, to marine climates.

}, keywords = {daylighting, energy conservation, energy consumption, energy efficiency, energy management systems, lighting control systems}, doi = {10.1007/s12273-009-9126-z}, author = {Eric Shen and Tianzhen Hong} } @article {421, title = {Technical Assistance to Beichuan Reconstruction: Creating and Designing Low- to Zero-carbon Communities in New Beichuan}, year = {2009}, month = {2009}, institution = {LBNL}, issn = {LBNL-2819E}, url = {http://www.escholarship.org/uc/item/0vv4m1gb}, author = {Tengfang T. Xu and Chuang Wang and Tianzhen Hong and Mark D. Levine} } @article {239, title = {Towards a Very Low Energy Building Stock: Modeling the US Commercial Building Stock to Support Policy and Innovation Planning}, journal = {Building Research and Information}, volume = {37:5}, year = {2009}, chapter = {610}, abstract = {

This paper describes the origin, structure and continuing development of a model of time varying energy consumption in the US commercial building stock. The model is based on a flexible structure that disaggregates the stock into various categories (e.g. by building type, climate, vintage and life-cycle stage) and assigns attributes to each of these (e.g. floor area and energy use intensity by fuel type and end use), based on historical data and user-defined scenarios for future projections. In addition to supporting the interactive exploration of building stock dynamics, the model has been used to study the likely outcomes of specific policy and innovation scenarios targeting very low future energy consumption in the building stock. Model use has highlighted the scale of the challenge of meeting targets stated by various government and professional bodies, and the importance of considering both new construction and existing buildings.

}, author = {Brian E. Coffey and Sam Borgeson and Stephen E. Selkowitz and Joshua S. Apte and Paul A. Mathew and Philip Haves} } @proceedings {247, title = {Application of Machine Learning in Fault Diagnostics of Mechanical Systems}, journal = {International Conference on Modeling, Simulation and Control}, year = {2008}, month = {10/2008}, author = {Massieh Najafi and David M. Auslander and Peter L. Bartlett and Philip Haves} } @proceedings {263, title = {Benchmarking and Equipment and Controls Assessment for a {\textquoteleft}Big Box{\textquoteright} Retail Chain}, journal = {ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2008}, month = {2008}, address = {Asilomar, California, USA}, abstract = {

The paper describes work to enable improved energy performance of existing and new retail stores belonging to a national chain and thereby also identify measures and tools that would improve the performance of {\textquoteleft}big box{\textquoteright} stores generally. A detailed energy simulation model of a standard store design was developed and used to:

The core enabling task of the project was to develop an energy model of the current standard design using the EnergyPlus simulation program. For the purpose of verification of the model against actual utility bills, the model was reconfigured to represent twelve existing stores (seven relatively new stores and five older stores) in different US climates and simulations were performed using weather data obtained from the National Weather Service. The results of this exercise, which showed generally good agreement between predicted and measured total energy use, suggest that dynamic benchmarking based on energy simulation would be an effective tool for identifying operational problems that affect whole building energy use. The models of the seven newer stores were then configured with manufacturers{\textquoteright} performance data for the equipment specified in the current design and used to assess the energy and cost benefits of increasing the efficiency of selected HVAC, lighting and envelope components. The greatest potential for cost-effective energy savings appears to be a substantial increase in the efficiency of the blowers in the roof top units and improvements in the efficiency of the lighting. The energy benefits of economizers on the roof-top units were analyzed and found to be very sensitive to the operation of the exhaust fans used to control building pressurization.

}, author = {Philip Haves and Brian E. Coffey and Scott Williams} } @article {413, title = {Comparing computer run time of building simulation programs}, journal = {Building Simulation}, volume = {1}, year = {2008}, month = {2008}, pages = {210-213}, abstract = {

This paper presents an approach to comparing computer run time of building simulation programs. The computing run time of a simulation program depends on several key factors, including the calculation algorithm and modeling capabilities of the program, the run period, the simulation time step, the complexity of the energy models, the run control settings, and the software and hardware configurations of the computer that is used to make the simulation runs. To demonstrate the approach, simulation runs are performed for several representative DOE-2.1E and EnergyPlus energy models. The computer run time of these energy models are then compared and analyzed.

}, keywords = {computer run time, doe-2, energyplus, simulation program}, doi = {10.1007/s12273-008-8123-y}, author = {Tianzhen Hong and Walter F. Buhl and Philip Haves and Stephen E. Selkowitz and Michael Wetter} } @proceedings {414, title = {Comparisons of HVAC Simulations between EnergyPlus and DOE-2.2 for data centers}, journal = {ASHRAE Conference}, volume = {115 Part 1}, year = {2008}, month = {2009}, keywords = {data center, doe-2, energy performance, energyplus, simulation}, author = {Tianzhen Hong and Dale A. Sartor and Paul A. Mathew and Mehry Yazdanian} } @article {419, title = {EnergyPlus Analysis Capabilities for Use in Title 24}, year = {2008}, month = {2008}, institution = {LBNL}, keywords = {building simulation, code compliance, energyplus, title 24}, issn = {LBNL-822E}, url = {http://www.escholarship.org/uc/item/0z78090x}, author = {Tianzhen Hong and Walter F. Buhl and Philip Haves} } @article {420, title = {EnergyPlus Run Time Analysis}, year = {2008}, month = {2008}, institution = {LBNL}, issn = {LBNL-1311E, CEC-500-2008-094}, url = {http://escholarship.org/uc/item/36h4m5z0}, author = {Tianzhen Hong and Walter F. Buhl and Philip Haves} } @proceedings {246, title = {Fault Diagnostics and Supervised Testing: How Fault Diagnostic tools can be Proactive?}, journal = {Eleventh International Conference on Intelligent Systems and Controls}, year = {2008}, month = {11/2008}, abstract = {The topic of fault detection and diagnostics (FDD) is studied from the perspective of proactive testing. Unlike most research focus in the diagnosis area in which system outputs are analyzed for diagnosis purposes, in this paper the focus is on the other side of the problem: manipulating system inputs for better diagnosis reasoning. In other words, the question of how diagnostic mechanisms can direct system inputs for better diagnosis analysis is addressed here. It is shown how the problem can be formulated as decision making problem coupled with a Bayesian Network based diagnostic mechanism. The developed mechanism is applied to the problem of supervised testing in HVAC systems.}, url = {http://www.actapress.com/Content_of_Proceeding.aspx?proceedingID=503}, author = {Massieh Najafi and David M. Auslander and Peter L. Bartlett and Philip Haves} } @conference {61, title = {A Modular Building Controls Virtual Test Bed for the Integration of Heterogeneous Systems}, booktitle = {SimBuild 2008, July 30-August 1}, year = {2008}, month = {08/2008}, address = {Berkeley, CA}, abstract = {

This paper describes the Building Controls Virtual Test Bed (BCVTB) that is currently under development at Lawrence Berkeley National Laboratory. An earlier prototype linked EnergyPlus with controls hardware through embedded SPARK models and demonstrated its value in more cost-effective envelope design and improved controls sequences for the San Francisco Federal Building. The BCVTB presented here is a more modular design based on a middleware that we built using Ptolemy II, a modular software environment for design and analysis of heterogeneous systems. Ptolemy II provides a graphical model building environment, synchronizes the exchanged data and visualizes the system evolution during run-time. Our additions to Ptolemy II allow users to couple to Ptolemy II a prototype version of EnergyPlus, MATLAB/Simulink or other simulation programs for data exchange during run-time. In future work we will also implement a BACnet interface that allows coupling BACnet compliant building automation systems to Ptolemy II. We will present the architecture of the BCVTB and explain how users can add their own simulation programs to the BCVTB. We will then present an example application in which the building envelope and the HVAC system was simulated in EnergyPlus, the supervisory control logic was simulated in MATLAB/Simulink and Ptolemy II was used to exchange data during run-time and to provide real-time visualization as the simulation progresses.

}, author = {Michael Wetter and Philip Haves} } @proceedings {227, title = {Object-oriented hygrothermal building physics library as a tool to predict and to ensure a thermal and hygric indoor comfort in building construction by using a Predicted-Mean-Vote (PMV) control ventilation system}, journal = {8th Nordic Symposium on Building Physics in the Nordic Countries 2008}, volume = {2}, year = {2008}, pages = {pp.825-832}, address = {Copenhagen, Denmark}, abstract = {

The indoor temperature and humidity conditions of the building envelope are important parameters for the evaluation of the thermal and hygric indoor comfort. In the research project GENSIM a new hygrothermal building library, based on the object- and equation-oriented model description language Modelica{\textregistered} has been developed by the Fraunhofer Institutes IBP and FIRST. This library includes many models as for instance a hygrothermal wall model, an air volume model, a zone model, a window model and an environment model. Due to the object-oriented modelling approach, some models of this library can be configured to a complex hygrothermal room model, which can predict the time dependent indoor temperature and humidity conditions in a building construction. In this paper we will introduce in a first step the object-oriented hygrothermal room model of this library. In a second step, the validation of the room model with some field experiments will be shown. In a third step we willpresent some simulation results, we obtained by coupling the room model with an implemented Predicted-Mean-Vote (PMV) control ventilation system to predict and to ensure a thermal and hygric indoor comfort in one case study. In the conclusion, the possible range of future applications of this new hygrothermal building physics library and demands for further research are indicated.

}, issn = {978-87-7877-265-7}, author = {Thierry Stephane Nouidui and Christoph Nytsch-Geusen and Andreas Holm and Klaus Sedlbauer} } @proceedings {245, title = {Overcoming the Complexity of Diagnostic Problems due to Sensor Network Architecture}, journal = {Eleventh International Conference on Intelligent Systems and Controls}, year = {2008}, month = {11/08}, abstract = {

In fault detection and diagnostics, limitations coming from the sensor network architecture are one of the main challenges in evaluating a system{\textquoteright}s health status. Usually the design of the sensor network architecture is not solely based on diagnostic purposes, other factors like controls, financial constraints, and practical limitations are also involved. As a result, it quite common to have one sensor (or one set of sensors) monitoring the behaviour of two or more components. This can significantly extend the complexity of diagnostic problems. In this paper a systematic approach is presented to deal with such complexities. It is shown how the problem can be formulated as a Bayesian network based diagnostic mechanism with latent variables. The developed approach is also applied to the problem of fault diagnosis in HVAC systems, an application area with considerable modeling and measurement constraints.

}, url = {https://www.actapress.com/Content_Of_Proceeding.aspx?ProceedingID=503}, author = {Massieh Najafi and David M. Auslander and Peter L. Bartlett and Philip Haves} } @conference {3388, title = {Using SPARK as a Solver for Modelica}, booktitle = {SimBuild 2008}, year = {2008}, month = {07/2008}, address = {Berkeley, CA, USA}, author = {Michael Wetter and Philip Haves and Michael A. Moshier and Edward F. Sowell} } @proceedings {62, title = {Using SPARK as a solver for Modelica}, journal = {Proc. of the 3rd SimBuild Conference}, year = {2008}, month = {08/2008}, address = {Berkeley, CA, USA}, abstract = {

Modelica is an object-oriented acausal modeling language that is well positioned to become a de-facto standard for expressing models of complex physical systems. To simulate a model expressed in Modelica, it needs to be translated into executable code. For generating run-time efficient code, such a translation needs to employ algebraic formula manipulations. As the SPARK solver has been shown to be competitive for generating such code but currently cannot be used with the Modelica language, we report in this paper how SPARK{\textquoteright}s symbolic and numerical algorithms can be implemented in OpenModelica, an open-source implementation of a Modelica modeling and simulation environment. We also report benchmark results that show that for our air flow network simulation benchmark, the SPARK solver is competitive with Dymola, which is believed to provide the best solver for Modelica.

}, url = {http://www.ibpsa.us/simbuild2008/technical_sessions/SB08-DOC-TS03-1-Wetter.pdf}, author = {Michael Wetter and Philip Haves and Michael A. Moshier and Edward F. Sowell} } @proceedings {266, title = {The Building Controls Virtual Test Bed {\textendash} a Simulation Environment for Developing and Testing Control Algorithms, Strategies and Systems}, journal = {Building Simulation {\textquoteright}07}, year = {2007}, address = {Bejing, China}, abstract = {

The paper describes the design of a Building Controls Virtual Test Bed (BCVTB), a simulation environment for the development of control algorithms and strategies for the major energy systems in buildings, HVAC, lighting, active facades and on-site generation. The BCVTB is based on the whole building energy simulation program EnergyPlus and includes both the pure simulation and the hardware-in-the-loop methods of implementing the controls. For convenience and scalability, the design of the hardware-in-the-loop interface for supervisory controls uses BACnet rather than the analog interface used for local loop control. The paper concludes with a case study of the use of a prototype implementation of the BCVTB to precommission the building control system for the naturally-ventilated San Francisco Federal Building. A number of problems were found with the control program, demonstrating the value of the precommissioning and the effectiveness of the technique.

}, keywords = {controls, development system, hardware-in-the-loop, testing}, url = {http://www.ibpsa.org/proceedings/BS2007/p748_final.pdf}, author = {Philip Haves and Peng Xu} } @conference {3390, title = {Comparison of Co-Simulation Approaches for Building and HVAC/R System Simulation}, booktitle = {Proc. Building Simulation 2007}, year = {2007}, month = {09/2007}, address = {Beijing, China}, author = {Marija Trcka and Michael Wetter and Jan Hensen} } @proceedings {63, title = {Comparison of co-simulation approaches for building and HVAC/R system simulation.
}, journal = {Proc. of the 10th IBPSA Conference}, year = {2007}, month = {09/2007}, pages = {1418-1425}, address = {Beijing, China}, abstract = {Appraisal of modern performance-based energy codes, as well as heating, ventilation, air- conditioning and refrigeration (HVAC/R) system*design require use of an integrated building and system performance simulation program. However, the required scope of the modeling library of such integrated tools often goes beyond those offered in available simulation programs. One remedy for this situation would be to develop the required models in an existing simulation program. However, due to the lack of model interoperability, the model would not be available in other simulation programs. We suggest co-simulation for HVAC/R system simulation as an approach to alleviate the above issues. In co-simulation, each subsystem is modeled and simulated in the appropriate simulation program, potentially on different computers, and intermediate results are communicated over the network during execution time. We discuss different co-simulation approaches and give insights into specific prototypes. Based on the prototypes, we compare the approaches in terms of accuracy, stability and execution time, using a simple case study. We finish with results discussions and recommendations on how to perform co-simulation to maintain the required accuracy of simulation results.}, url = {http://www.ibpsa.org/proceedings/BS2007/p503_final.pdf}, author = {Marija Trcka and Michael Wetter and Jan Hensen} } @conference {2656, title = {Potential of Buried Pipes Systems and Derived Techniques for Passive Cooling of Buildings in Brazilian Climates}, booktitle = {Proc. Building Simulation 2007}, year = {2007}, month = {09/2007}, address = {Beijing, China}, author = {Pierre Hollmuller and Joyce Carlo and Martin Ordenes and Fernando Westphal and Roberto Lamberts} } @article {2923, title = {A Semi-automated Commissioning Tool for VAV Air Handling Units: Functional Test Analyzer}, journal = {ASHRAE Transactions}, volume = {113}, number = {Part 1}, year = {2007}, month = {01/2007}, pages = {380-391}, abstract = {

A software tool that automates the analysis of functional tests for air-handling units is described. The tool compares the performance observed during manual tests with the performance predicted by simple models of the components under test that are configured using design information and catalog data. Significant differences between observed and expected performance indicate the presence of faults. Fault diagnosis is performed by analyzing the variation of these differences with operating point using expert rules and fuzzy inferencing.

The tool has a convenient user interface to facilitate manual entry of measurements made during a test. A graphical display compares the measured and expected performance, highlighting significant differences that indicate the presence of faults. The tool is designed to be used by commissioning providers conducting functional tests as part of either new building commissioning or retro-commissioning, as well as by building owners and operators conducting routine tests to check the performance of their HVAC systems. The paper describes the input data requirements of the tool, the software structure, the graphical interface, and summarizes the development and testing process used.

}, url = {http://gaia.lbl.gov/btech/papers/60979.pdf}, author = {Philip Haves and Moosung Kim and Massieh Najafi and Peng Xu} } @conference {2654, title = {Simulation Enhanced Prototyping of an Experimental Solar House}, booktitle = {Proc. Building Simulation 2007}, year = {2007}, month = {09/2007}, address = {Beijing, China}, author = {Ruchi Choudhary and Godfried Augenbroe and Russell Gentry and Huafen Hu} } @conference {2658, title = {Use of Simulation Tools for Managing Buildings Energy Demand}, booktitle = {Proc. Building Simulation 2007}, year = {2007}, month = {09/2007}, address = {Beijing, China}, author = {Alberto Hernandez and Fl{\'a}vio Neto and Augusto Sanzovo Fiorelli} } @proceedings {229, title = {Advanced modeling and simulation techniques in MOSILAB: A system development case study}, journal = {5th International Modelica Conference}, year = {2006}, pages = {pp.63-72}, author = {Christoph Nytsch-Geusen and Thilo Ernst and Peter Schwarz and Mathias Vetter and Andreas Holm and Juergen Leopold and Alexander Mattes and Andre Nordwig and Peter Schneider and Christoph Wittwer and Thierry Stephane Nouidui and Gerhardt Schmidt} } @proceedings {2811, title = {An Analysis of Building Envelope Upgrades for Residential Energy Efficiency in Hot and Humid Climates}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Mini Malhotra and Jeff S. Haberl} } @proceedings {2813, title = {The Application of Building Energy Simulation and Calibration in Two High-Rise Commercial Buildings in Shanghai}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Yiqun Pan and Zhizhong Huang and Gang Wu and Chen Chen} } @article {271, title = {Case Study of Demand Shifting with Thermal Mass in Two Large Commercial Buildings}, journal = {ASHRAE Transactions}, volume = {112}, year = {2006}, chapter = {572}, author = {Peng Xu and Philip Haves} } @proceedings {3391, title = {Development of a Model Specification for Performance Monitoring Systems for Commercial Buildings}, journal = {2006 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2006}, month = {08/2006}, address = {Pacific Grove, CA, USA}, author = {Philip Haves and Robert J. Hitchcock and Kenneth L. Gillespie and Martha Brook and Christine Shockman and Joseph J Deringer and Kristopher L. Kinney} } @proceedings {268, title = {Development of a Model Specification for Performance Monitoring Systems for Commercial Buildings}, journal = {2006 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2006}, month = {08/2006}, address = {Asilomar, California, USA}, abstract = {

The paper describes the development of a model specification for performance monitoring systems for commercial buildings. The specification focuses on four key aspects of performance monitoring: performance metrics measurement system requirements data acquisition and archiving data visualization and reporting The aim is to assist building owners in specifying the extensions to their control systems that are required to provide building operators with the information needed to operate their buildings more efficiently and to provide automated diagnostic tools with the information required to detect and diagnose faults and problems that degrade energy performance. The paper reviews the potential benefits of performance monitoring, describes the specification guide and discusses briefly the ways in which it could be implemented. A prototype advanced visualization tool is also described, along with its application to performance monitoring. The paper concludes with a description of the ways in which the specification and the visualization tool are being disseminated and deployed.

}, url = {http://www.aceee.org/proceedings-paper/ss06/panel03/paper10}, author = {Philip Haves and Robert J. Hitchcock and Kenneth L. Gillespie and Martha Brook and Christine Shockman and Joseph J Deringer and Kristopher L. Kinney} } @proceedings {3392, title = {Dynamic Controls for Energy Efficiency and Demand Response: Framework Concepts and a New Construction Case Study in New York}, journal = {2006 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2006}, month = {08/2006}, address = {Pacific Grove, CA, USA}, author = {Sila Kiliccote and Mary Ann Piette and David S. Watson and Glenn D. Hughes} } @proceedings {2804, title = {Experience Testing EnergyPlus With the IEA HVAC Bestest E300-E545 Series and IEA HVAC Bestest Fuel-Fired Furnace Series}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Michael J. Witte and Robert H. Henninger and Drury B. Crawley} } @proceedings {270, title = {A Guide for Specifying Performance Monitoring Systems in Commercial and Institutional Buildings}, journal = {14th National Conference on Building Commissioning}, year = {2006}, month = {2006}, address = {San Francisco, CA}, abstract = {

This paper describes a guide for specifying performance monitoring systems that was developed as part of jointly funded CEC PIER-DOE project intended to assist commercial and institutional building owners in specifying what is required to obtain the information necessary to initiate and sustain an ongoing commissioning activity. The project{\textquoteright}s goal was to facilitate the delivery of specific performance related information to the benefit of both commissioning providers and building operators. A number of large-building owners were engaged in order to help create {\textquoteright}market pull{\textquoteright} for performance monitoring while producing a specification that met their needs. The specification guide and example specification language addresses four key aspects of performance monitoring:

The paper describes key aspects of the guide including how measurement accuracy requirements relate to the performance metrics that are used in both troubleshooting and routine reporting. Guide development activities and related tech-transfer efforts are also presented.

}, author = {Kenneth L. Gillespie and Philip Haves and Robert J. Hitchcock and Joseph J Deringer and Kristopher L. Kinney} } @proceedings {2789, title = {Halfway to Zero Energy in a Large Office Building}, journal = {2006 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2006}, month = {08/2006}, address = {Pacific Grove, CA, USA}, author = {Mark Hanson and Steven Carlson and Dan Sammartano and Thomas Taylor} } @proceedings {269, title = {A Library of HVAC Component Models for use in Automated Diagnostics}, journal = {SimBuild 2006}, year = {2006}, address = {Boston, MA}, abstract = {

The paper describes and documents a library of equipment reference models developed for automated fault detection and diagnosis of secondary HVAC system (air handling units and air distribution systems). The models are used to predict the performance that would be expected in the absence of faults. The paper includes a description of the use of automatic documentation methods in the library.

}, url = {http://www.ibpsa.us/pub/simbuild2006/papers/SB06_034_041.pdf}, author = {Peng Xu and Philip Haves and Dimitri Curtil} } @conference {12052, title = {Measured energy performance of a US-China demonstration energy-efficient commercial building}, booktitle = {2007 ASHRAE Winter Meeting, January 27-31, 2007}, year = {2006}, month = {01/2007}, address = {Dallas, TX}, abstract = {

In July 1998, the U.S. Department of Energy (USDOE) and China{\textquoteright}s Ministry of Science of Technology (MOST) signed a Statement of Work (SOW) to collaborate on the design and construction of an energyefficient demonstration office building and design center to be located in Beijing. The proposed 13,000 m2 (140,000 ft2) nine-story office building would use U.S. energy-efficient materials, space-conditioning systems, controls, and design principles that were judged to be widely replicable throughout China. The SOW stated that China would contribute the land and provide for the costs of the base building, while the U.S. would be responsible for the additional (or marginal) costs associated with the package of energy efficiency andrenewable energy improvements to the building. The project was finished and the building occupied in 2004.

Using DOE-2 to analyze the energy performance of the as-built building, the building obtained 44 out of 69 possible points according to the Leadership in Energy and Environmental Design (LEED) rating, including the full maximum of 10 points in the energy performance section. The building achieved a LEED Gold rating, the first such LEED-rated office building in China, and is 60\% more efficient than ASHRAE 90.1-1999. The utility data from the first year{\textquoteright}s operation match well the analysis results, providing that adjustments are made for unexpected changes in occupancy and operations. Compared with similarly equipped office buildings in Beijing, this demonstration building uses 60\% less energy per floor area. However, compared to conventional office buildings with less equipment and window air-conditioners, the building uses slightly more energy per floor area.

}, author = {Peng Xu and Yu Joe Huang and Ruidong Jin and Guoxiong Yang} } @proceedings {47, title = {Modelica versus TRNSYS {\textemdash} A Comparison Between an Equation-Based and a Procedural Modeling Language for Building Energy Simulation}, journal = {Proc. of the 2nd SimBuild Conference}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, abstract = {

The EnergyPlus building energy simulation software has been tested using the IEA HVAC BESTEST E300-E545 series of tests and the IEA HVAC BESTEST Fuel-Fired test series. The first is a series of comparative tests for a single-zone DX cooling system which tests a program{\textquoteright}s ability to model hourly loads over an expanded range of performance conditions for various air mixing, infiltration, thermostat set-up, overload conditions, and various economizer control schemes. The second is a series of analytical/semianalytical comparative tests for a single-zone fuel-fired furnace which tests a program{\textquoteright}s ability to model steady state performance, varying outdoor and indoor conditions, and circulating and draft fan operation. Each of these HVAC BESTEST series were used to test EnergyPlus prior to new public releases. The application of these tests proved to be very useful in several ways: a) revealed algorithmic errors which were fixed, b) revealed algorithmic shortcomings which were improved or eliminated through the use of more rigorous calculations for certain components, and c) caught newly introduced bugs before public release of updates.

}, url = {http://www.ibpsa.us/pub/simbuild2006/papers/SB06_001_008.pdf}, author = {Michael Wetter and Christoph Haugstetter} } @proceedings {2810, title = {Performance of High-Performance Glazing in IECC Compliant Building Simulation Model (DOE-2)}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Jaya Mukhopadhyay and Jeff S. Haberl} } @proceedings {3396, title = {Using EnergyPlus for California Title-24 Compliance Calculations}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Yu Joe Huang and Norman Bourassa and Walter F. Buhl and Ender Erdem and Robert J. Hitchcock} } @conference {1945, title = {Using EnergyPlus for California Title-24 compliance calculations}, booktitle = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA}, abstract = {

For the past decade, the non-residential portion of California{\textquoteright}s Title-24 building energy standard has relied on DOE-2.1E as the reference computer simulation program for development as well as compliance. However, starting in 2004, the California Energy Commission has been evaluating the possible use of EnergyPlus as the reference program in future revisions of Title-24. As part of this evaluation, the authors converted the Alternate Compliance Method (ACM) certification test suite of 150 DOE-2 files to EnergyPlus, and made parallel DOE-2 and EnergyPlus runs for this extensive set of test cases. A customized version of DOE-2.1E named doe2ep was developed to automate the conversion process. This paper describes this conversion process, including the difficulties in establishing an apples-to-apples comparison between the two programs, and summarizes how the DOE-2 and EnergyPlus results compare for the ACM test cases.

}, author = {Yu Joe Huang and Norman Bourassa and Walter F. Buhl and Ender Erdem and Robert J. Hitchcock} } @proceedings {228, title = {Validierung der eindimensionalen hygrothermischen Wandmodelle der Modelica-Bibliothek "BuildingPhysicsLibrary"}, journal = {BauSIM 2006}, year = {2006}, pages = {pp.144-146}, address = {Munich, Germany}, isbn = {978-3-00-019823-6}, issn = {3-00-019823-7}, author = {Thierry Stephane Nouidui and Christoph Nytsch-Geusen and Andreas Holm} } @proceedings {2817, title = {Contrasting the Capabilities of Building Energy Performance Simulation Programs}, journal = {IBPSA Building Simulation 2005}, year = {2005}, month = {08/2005}, address = {Montreal, Canada}, author = {Drury B. Crawley and Jon W. Hand and Michael Kummert and Brent T. Griffith} } @conference {231, title = {A hygrothermal building model based on the object-oriented modeling language Modelica}, booktitle = {Ninth International IBPSA Conference}, year = {2005}, month = {2005}, address = {Montreal, Canada}, isbn = {2-553-01152-0}, author = {Christoph Nytsch-Geusen and Thierry Stephane Nouidui and Andreas Holm and Wolfram Haupt} } @conference {2667, title = {Improving the Data Available to Simulation Programs}, booktitle = {IBPSA Building Simulation 2005}, year = {2005}, month = {08/2005}, address = {Montreal, Canada}, abstract = {

Building performance simulation tools have significantly improved in quality and depth of analysis capability over the past thirty-five years. Yet despite these increased capabilities, simulation programs still depend on user entry for significant data about building components, loads, and other typically scheduled inputs. This often forces users to estimate values or find previously compiled sets of data for these inputs. Often there is little information about how the data were derived, what purposes it is fit for, which standards apply, uncertainty associated with each data field as well as a general description of the data.

A similar problem bedeviled access to weather data and Crawley, Hand, and Lawrie (1999) described a generalized weather data format developed for use with two energy simulation programs which has subsequently lead to a repository which is accessed by thousands of practitioners each year.

This paper describes a generalized format and data documentation for user input{\textemdash}whether it is building envelope components, scheduled loads, or environmental emissions{\textemdash}the widgets upon which all models are dependant. We present several examples of the new input data format including building envelope component, a scheduled occupant load, and environmental emissions.

}, author = {Jon W. Hand and Drury B. Crawley and Michael Donn and Linda K. Lawrie} } @article {273, title = {Model-Based Automated Functional Testing-Methodology and Application to Air Handling Units}, journal = {ASHRAE Transactions}, volume = {111}, year = {2005}, chapter = {979}, author = {Peng Xu and Philip Haves and Moosung Kim} } @proceedings {232, title = {MOSILAB: Development of a modelica based generic simulation tool supporting modal structural dynamics}, journal = {4th International Modelica Conference}, year = {2005}, pages = {pp.527-534}, address = {Hamburg, Germany}, author = {Christoph Nytsch-Geusen and Thilo Ernst and Peter Schneider and Mathias Vetter and Andreas Holm and Juergen Leopold and Ullrich Doll and Andre Nordwig and Peter Schwarz and Christoph Wittwer and Thierry Stephane Nouidui and Gerhardt Schmidt and Alexander Mattes} } @conference {2907, title = {A Semi-Automated Functional Test Data Analysis Tool}, booktitle = {13th National Conference on Building Commissioning}, series = {Proceedings of the 13th National Conference on Building Commissioning}, year = {2005}, address = {New York City, NY}, abstract = {

The growing interest in commissioning is creating a demand that will increasingly be met by mechanical contractors and less experienced commissioning agents. They will need tools to help them perform commissioning effectively and efficiently. The widespread availability of standardized procedures, accessible in the field, will allow commissioning to be specified with greater certainty as to what will be delivered, enhancing the acceptance and credibility of commissioning. In response, a functional test data analysis tool is being developed to analyze the data collected during functional tests for air-handling units.

The functional test data analysis tool is designed to analyze test data, assess performance of the unit under test and identify the likely causes of the failure. The tool has a convenient user interface to facilitate manual entry of measurements made during a test. A graphical display shows the measured performance versus the expected performance, highlighting significant differences that indicate the unit is not able to pass the test. The tool is described as semi-automated because the measured data need to be entered manually, instead of being passed from the building control system automatically. However, the data analysis and visualization are fully automated. The tool is designed to be used by commissioning providers conducting functional tests as part of either new building commissioning or retro-commissioning, as well as building owners and operators interested in conducting routine tests periodically to check the performance of their HVAC systems.

}, author = {Peng Xu and Philip Haves and Moosung Kim} } @conference {1806, title = {A Simulation-Based Testing and Training Environment for Building Controls}, booktitle = {SimBuild 2004, Building Sustainability and Performance Through Simulation}, year = {2005}, month = {08/2004}, address = {Boulder, CO}, abstract = {

A hybrid simulation environment for controls testing and training is described. A real-time simulation of a building and HVAC system is coupled to a real building control system using a hardware interface. A prototype has been constructed and tested in which the dynamic performance of both the HVAC equipment and the building envelope is simulated using SPARK (Simulation Problem Analysis and Research Kernel). A low cost hardware interface between the simulation and the real control system is implemented using plug-in analog-to-digital and digital-to-analog cards in a personal computer. The design and implementation of the hardware interface in SPARK are described. The development of a variant of this environment that uses a derivative of EnergyPlus to test the implementation of a natural ventilation control strategy in real control hardware is also described.

Various applications of the hybrid simulation environment are briefly described, including the development of control algorithms and strategies, control system product testing and the pre-commissioning of building control system installations. The application to the education and training of building operators and HVAC service technicians is discussed in more detail, including the development of a community college curriculum that includes the use of the hybrid simulation environment to teach both control system configuration and HVAC troubleshooting.

}, author = {Peng Xu and Philip Haves and Joseph J Deringer} } @conference {3382, title = {Two DOE-2 functions}, booktitle = {IBPSA Building Simulation}, year = {2005}, month = {2005}, address = {Canada}, abstract = {This paper presents two DOE-2 functions to expand the modeling capability of DOE-2.1E, a popular calculation engine for building energy simulations. The first function models sensible and total heat recovery between outside air and exhaust air, with optional evaporative precooling of exhaust air before the heat recovery. The existing heat recovery of DOE-2 only allows preheating outside air when exhaust air is more than 10{\textdegree}F warmer than outside air. The second function models distributed energy storage for direct expansion air conditioners which cannot be modeled by any existing system type of DOE-2.1E.}, url = {http://www.ibpsa.org/proceedings/BS2005/BS05_0419_426.pdf}, author = {Tianzhen Hong and Charles N. Eley and Erik Kolderup} } @conference {2669, title = {Two DOE-2 Functions}, booktitle = {IBPSA Building Simulation 2005}, year = {2005}, month = {08/2005}, address = {Montreal, Canada}, author = {Tianzhen Hong and Charles N. Eley and Erik Kolderup} } @article {11714, title = {Design and Testing of a Control Strategy for a Large Naturally Ventilated Office Building}, journal = {Building Services Engineering Research \& Technology}, volume = {25}, number = {3}, year = {2004}, pages = {211-221}, abstract = {

The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. Each floor is designed to be cross-ventilated, through upper windows that are controlled by the building management system. Users have control over lower level windows, which can be as much as 50\% of the total openable area. There are significant differences in the performance and the control of the windward and leeward sides of the building, and separate monitoring and control strategies are determined for each side. The performance and control of the building has been designed and tested using a modified version of EnergyPlus. Results from studies with EnergyPlus and computational fluid dynamics are used in designing the control strategy. Wind-driven cross-ventilation produces a main jet through the upper openings of the building, across the ceiling from the windward to the leeward side. Below this jet, the occupied regions are subject to a recirculating airflow. Results show that temperatures within the building are predicted to be satisfactory, provided a suitable control strategy is implemented that uses night cooling in periods of hot weather. The control strategy has 10 window opening modes. EnergyPlus was extended to simulate the effects of these modes, and to assess the effects of different forms of user behaviour. The results show how user behaviour can significantly influence the building performance.

(Note: PDF contains both LBNL-56010 \& LBNL-56010 Conf.)

}, author = {Guilherme Carrilho da Gra{\c c}a and Paul F. Linden and Philip Haves} } @article {280, title = {Design and Testing of a Control Strategy for a Large Naturally Ventilated Office Building}, journal = {Building Services Engineering Research \& Technology}, volume = {25}, year = {2004}, pages = {223-239}, abstract = {The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. Each floor is designed to be cross-ventilated, through upper windows that are controlled by the building management system. Users have control over lower level windows, which can be as much as 50\% of the total openable area. There are significant differences in the performance and the control of the windward and leeward sides of the building, and separate monitoring and control strategies are determined for each side. The performance and control of the building has been designed and tested using a modified version of EnergyPlus. Results from studies with EnergyPlus and computational fluid dynamics are used in designing the control strategy. Wind-driven cross-ventilation produces a main jet through the upper openings of the building, across the ceiling from the windward to the leeward side. Below this jet, the occupied regions are subject to a recirculating airflow. Results show that temperatures within the building are predicted to be satisfactory, provided a suitable control strategy is implemented that uses night cooling in periods of hot weather. The control strategy has 10 window opening modes. EnergyPlus was extended to simulate the effects of these modes, and to assess the effects of different forms of user behaviour. The results show how user behaviour can significantly influence the building performance.}, doi = {10.1191/0143624404bt107oa}, url = {http://bse.sagepub.com/content/25/3/223}, author = {Guilherme Carrilho da Gra{\c c}a and Paul F. Linden and Philip Haves} } @article {2588, title = {Development of a Thermal Energy Storage Model for EnergyPlus}, journal = {Energy and Buildings}, volume = {36}, year = {2004}, month = {2004}, pages = {807-814}, chapter = {807}, keywords = {energyplus, thermal energy storage (tes) system}, author = {Pyeongchan Ihm and Moncef Krarti and Gregor P. Henze} } @proceedings {2820, title = {Development of Trade-Off Equations for EnergyStar Windows}, journal = {SimBuild 2004, Building Sustainability and Performance Through Simulation}, year = {2004}, month = {08/2004}, address = {Boulder, Colorado, USA}, author = {Yu Joe Huang and Robin Mitchell and Stephen E. Selkowitz} } @proceedings {2823, title = {EnergyPlus: An Update}, journal = {SimBuild 2004, Building Sustainability and Performance Through Simulation}, year = {2004}, month = {08/2004}, address = {Boulder, Colorado, USA}, author = {Drury B. Crawley and Linda K. Lawrie and Curtis O. Pedersen and Frederick C. Winkelmann and Michael J. Witte and Richard K. Strand and Richard J. Liesen and Walter F. Buhl and Yu Joe Huang and Robert H. Henninger and Jason Glazer and Daniel E. Fisher and Don B. Shirley and Brent T. Griffith and Peter G. Ellis and Lixing Gu} } @proceedings {2832, title = {Experience Testing EnergyPlus With the ASHRAE 1052-RP Building Fabric Analytical Tests}, journal = {SimBuild 2004, Building Sustainability and Performance Through Simulation}, year = {2004}, month = {08/2004}, address = {Boulder, Colorado, USA}, author = {Michael J. Witte and Robert H. Henninger and Drury B. Crawley} } @proceedings {285, title = {Graph-theoretic Methods in Simulation Using SPARK}, journal = {High Performance Computing Symposium of the Advanced Simulation Technologies Conference}, year = {2004}, month = {04/2004}, address = {Arlington, VA}, abstract = {This paper deals with simulation modeling of nonlinear, deterministic, continuous systems. It describes how the Simulation Problem Analysis and Research Kernel (SPARK) uses the mathematical graph both to describe models of such systems, and to solve the embodied differential-algebraic equation systems (DAEs). Problems are described declaratively rather than algorithmically, with atomic objects representing individual equations and macro objects representing larger programming entities (submodels) in a smooth hierarchy. Internally, in a preprocessing step, graphs are used to represent the problem at the level of equations and variables rather than procedural, multi-equation blocks. Benefits obtained include models that are without predefined input and output sets, enhancing modeling flexibility and code reusability, and relieving the modeler from manual algorithm development. Moreover, graph algorithms are used for problem decomposition and reduction, greatly reducing solution time for wide classes of problems. After describing the methodology the paper presents results of benchmark tests that quantify performance advantages relative to conventional methods. In a somewhat contrived nonlinear example we show O performance as opposed}, author = {Edward F. Sowell and Michael A. Moshier and Philip Haves} } @proceedings {2834, title = {Graph-Theoretic Methods in Simulation Using SPARK}, journal = {High Performance Computing Symposium of the Advanced Simulation Technologies Conference (Society for Modeling Simulation International)}, year = {2004}, month = {04/2004}, address = {Arlington, Virginia, USA}, author = {Edward F. Sowell and Michael A. Moshier and Philip Haves and Dimitri Curtil} } @conference {56064, title = {Peak Demand Reduction from Pre-Cooling with Zone Temperature Reset in an Office Building}, booktitle = {2004 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2004}, month = {08/2004}, address = {Pacific Grove, CA}, abstract = {

The objective of this study was to demonstrate the potential for reducing peak-period electrical demand in moderate-weight commercial buildings by modifying the control of the HVAC system. An 80,000 ft2 office building with a medium-weight building structure and high window-to-wall ratio was used for a case study in which zone temperature set-points were adjusted prior to and during occupancy. HVAC performance data and zone temperatures were recorded using the building control system. Additional operative temperature sensors for selected zones and power meters for the chillers and the AHU fans were installed for the study. An energy performance baseline was constructed from data collected during normal operation. Two strategies for demand shifting using the building thermal mass were then programmed in the control system and implemented progressively over a period of one month. It was found that a simple demand limiting strategy performed well in this building. This strategy involved maintaining zone temperatures at the lower end of the comfort region during the occupied period up until 2 pm. Starting at 2 pm, the zone temperatures were allowed to float to the high end of the comfort region. With this strategy, the chiller power was reduced by 80-100\% (1 - 2.3 W/ft2) during normal peak hours from 2 - 5 pm, without causing any thermal comfort complaints. The effects on the demand from 2 - 5 pm of the inclusion of pre-cooling prior to occupancy are unclear.

}, keywords = {demand shifting (pre-cooling)}, author = {Peng Xu and Philip Haves and Mary Ann Piette and James E. Braun} } @proceedings {282, title = {A simulation-based testing and training environment for building controls}, journal = {Simbuild 2004}, year = {2004}, address = {Boulder, CO}, abstract = {

A hybrid simulation environment for controls testing and training is described. A real-time simulation of a building and HVAC system is coupled to a real building control system using a hardware interface. A prototype has been constructed and tested in which the dynamic performance of both the HVAC equipment and the building envelope is simulated using SPARK (Simulation Problem Analysis and Research Kernel). A low cost hardware interface between the simulation and the real control system is implemented using plug-in analog-to-digital and digital-to-analog cards in a personal computer. The design and implementation of the hardware interface in SPARK are described. The development of a variant of this environment that uses a derivative of EnergyPlus to test the implementation of a natural ventilation control strategy in real control hardware is also described. Various applications of the hybrid simulation environment are briefly described, including the development of control algorithms and strategies, control system product testing and the pre-commissioning of building control system installations. The application to the education and training of building operators and HVAC service technicians is discussed in more detail, including the development of a community college curriculum that includes the use of the hybrid simulation environment to teach both control system configuration and HVAC troubleshooting.

}, author = {Peng Xu and Philip Haves and Joseph J Deringer} } @proceedings {2824, title = {Transferred Just on Paper? Why Doesn{\textquoteright}t the Reality of Transferring/Adapting Energy Efficiency Codes and Standards Come Close to the Potential?}, journal = {ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2004}, month = {08/2004}, address = {Pacific Grove, California, USA}, author = {Joseph J Deringer and Maithili Iyer and Yu Joe Huang} } @article {279, title = {Use of Simulation in the Design of a Large Naturally Ventilated Office Building}, journal = {Building Services Engineering Research \& Technology}, volume = {25}, year = {2004}, pages = {211-221}, abstract = {The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. The EnergyPlus thermal simulation program was used to evaluate different ventilation strategies for space cooling and rationalize the design of the fa{\c c}ade. The strategies include ventilation driven by different combinations of wind, internal stack and external stack. The simulation results indicate that wind-driven ventilation can maintain adequate comfort even during hot periods. Computational fluid dynamics was used to study the airflow and temperature distribution in the occupied spaces arising from different combinations of window openings and outside conditions and thereby inform both the design of the windows and the control strategy.}, doi = {10.1191/0143624404bt102oa}, url = {http://bse.sagepub.com/content/25/3/211}, author = {Philip Haves and Paul F. Linden and Guilherme Carrilho da Gra{\c c}a} } @article {2908, title = {An automated functional test and fault detection method}, year = {2003}, author = {Peng Xu and Moosung Kim and Philip Haves} } @proceedings {49, title = {Comparison of a generalized pattern search and a genetic algorithm optimization method}, journal = {Proc. of the 8th IBPSA Conference}, volume = {III}, year = {2003}, pages = {1401-1408}, address = {Eindhoven, Netherlands}, abstract = {

Building and HVAC system design can significantly improve if numerical optimization is used. However, if a cost function that is smooth in the design parameter is evaluated by a building energy simulation program, it usually becomes replaced with a numerical approximation that is discontinuous in the design parameter. Moreover, many building simulation programs do not allow obtaining an error bound for the numerical approximations to the cost function. Thus, if a cost function is evaluated by such a program, optimization algorithms that depend on smoothness of the cost function can fail far from a minimum.

For such problems it is unclear how the Hooke-Jeeves Generalized Pattern Search optimization algorithm and the simple Genetic Algorithm perform. The Hooke-Jeeves algorithm depends on smoothness of the cost function, whereas the simple Genetic Algorithm may not even converge if the cost function is smooth. Therefore, we are interested in how these algorithms perform if used in conjunction with a cost function evaluated by a building energy simulation program.

In this paper we show what can be expected from the two algorithms and compare their performance in minimizing the annual primary energy consumption of an office building in three locations. The problem has 13 design parameters and the cost function has large discontinuities. The optimization algorithms reduce the energy consumption by 7\% to 32\%, depending on the building location. Given the short labor time to set up the optimization problems, such reductions can yield considerable economic gains.

}, url = {http://www.ibpsa.org/proceedings/BS2003/BS03_1401_1408.pdf}, author = {Michael Wetter and Jonathan A. Wright}, editor = {Godfried Augenbroe and Jan Hensen} } @proceedings {48, title = {A convergent optimization method using pattern search algorithms with adaptive precision simulation}, journal = {Proceedings of the 8th IBPSA Conference}, volume = {III}, year = {2003}, pages = {1393-1400}, address = {Eindhoven, Netherlands}, abstract = {

In solving optimization problems for building design and control, the cost function is often evaluated using a detailed building simulation program. These programs contain code features that cause the cost function to be discontinuous. Optimization algorithms that require smoothness can fail on such problems. Evaluating the cost function is often so time-consuming that stochastic optimization algorithms are run using only a few simulations, which decreases the probability of getting close to a minimum. To show how applicable direct search, stochastic, and gradient-based optimization algorithms are for solving such optimization problems, we compare the performance of these algorithms in minimizing cost functions with different smoothness. We also explain what causes the large discontinuities in the cost functions.

}, keywords = {coordinate search, direct search, genetic algorithm, hooke{\textendash}jeeves, optimization, particle swarm optimization}, author = {Michael Wetter and Elijah Polak}, editor = {Godfried Augenbroe and Jan Hensen} } @proceedings {294, title = {Design and Testing of a Control Strategy for a Large Naturally Ventilated Office Building}, journal = {Building Simulation {\textquoteright}03}, year = {2003}, month = {08/2003}, address = {Eindhoven, Netherlands}, author = {Guilherme Carrilho da Gra{\c c}a and Paul F. Linden and Erin McConahey and Philip Haves} } @article {288, title = {Field Testing Model-Based Condition Monitoring on a HVAC Cooling Coil Sub-System}, journal = {Building Services Engineering Research \& Technology}, volume = {24}, year = {2003}, pages = {103-116}, author = {Richard A. Buswell and Philip Haves and Jonathan A. Wright} } @article {1563, title = {Library of component reference models for fault detection}, year = {2003}, author = {Peng Xu and Philip Haves} } @proceedings {293, title = {Use of Simulation in the Design of a Large Naturally Ventilated Commercial Office Building}, journal = {Building Simulation {\textquoteright}03}, year = {2003}, month = {08/2003}, address = {Eindhoven, Netherlands}, url = {http://www.inive.org/members_area/medias/pdf/Inive/IBPSA/UFSC912.pdf}, author = {Philip Haves and Guilherme Carrilho da Gra{\c c}a and Paul F. Linden} } @conference {2626, title = {VisualDOE {\textendash} A Green Design Tool}, booktitle = {The 4th International Symposium on HVAC}, year = {2003}, month = {2003}, address = {Beijing, China}, author = {Tianzhen Hong and Charles N. Eley and Erik Kolderup} } @article {302, title = {On Approaches to Couple Energy Simulation and Computational Fluid Dynamics Programs}, journal = {Building and Environment}, volume = {37}, year = {2002}, chapter = {857}, abstract = {

Energy simulation (ES) and computational fluid dynamics (CFD) can play important roles in building design by providing complementary information about the buildings{\textquoteright} environmental performance. However, separate applications of ES and CFD are usually unable to give an accurate prediction of building performance due to the assumptions involved in the separate calculations. Integration of ES and CFD eliminates many of these assumptions since the information provided by the models is complementary. Several different approaches to integrating ES and CFD are described. In order to bridge the discontinuities of time-scale, spatial resolution and computing speed between ES and CFD programs, a staged coupling strategy for different problems is proposed. The paper illustrates a typical dynamic coupling process by means of an example implemented using the EnergyPlus and MIT-CFD programs.

}, author = {Zhiqiang Zhai and Qingyan Chen and Philip Haves and Joseph H. Klems} } @conference {301, title = {A Computer Simulation Appraisal of Non-Residential Low Energy Cooling Systems in California}, booktitle = {2002 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2002}, month = {08/2002}, address = {Asilomar, California, USA}, abstract = {

An appraisal of the potential performance of different Low Energy Cooling (LEC) systems in nonresidential buildings in California is being conducted using computer simulation. The paper presents results from the first phase of the study, which addressed the systems that can be modeled, with the DOE-2.1E simulation program.

The following LEC technologies were simulated as variants of a conventional variable-air-volume system with vapor compression cooling and mixing ventilation in the occupied spaces:

Results are presented for four populous climates, represented by Oakland, Sacramento, Pasadena and San Diego. The greatest energy savings are obtained from a combination of displacement ventilation and air-side indirect/direct evaporative pre-cooling. Cool beam systems have the lowest peak demand but do not reduce energy consumption significantly because the reduction in fan energy is offset by a reduction in air-side free cooling. Overall, the results indicate significant opportunities for LEC technologies to reduce energy consumption and demand in non-residential new construction and retrofit.

}, author = {Norman Bourassa and Philip Haves and Yu Joe Huang} } @proceedings {299, title = {Field Testing of Component-Level Model-Based Fault Detection Methods for Mixing Boxes and VAV Fan Systems}, journal = {2002 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2002}, month = {08/2002}, address = {Asilomar, California, USA}, abstract = {

An automated fault detection and diagnosis tool for HVAC systems is being developed, based on an integrated, lifecycle, approach to commissioning and performance monitoring. The tool uses component-level HVAC equipment models implemented in the SPARK equation-based simulation environment. The models are configured using design information and component manufacturers{\textquoteright} data and then fine-tuned to match the actual performance of the equipment by using data measured during functional tests of the sort using in commissioning. This paper presents the results of field tests of mixing box and VAV fan system models in an experimental facility and a commercial office building. The models were found to be capable of representing the performance of correctly operating mixing box and VAV fan systems and detecting several types of incorrect operation.

}, author = {Peng Xu and Philip Haves} } @conference {2955, title = {Field Testing of Component-Level Model-Based Fault Detection Methods for Mixing Boxes and VAV Fan Systems}, booktitle = {2002 American Council for an Energy-Efficient Economy Summer Study on Energy Efficiency in Buildings}, year = {2002}, month = {05/2002}, address = {Pacific Grove, California}, abstract = {

An automated fault detection and diagnosis tool for HVAC systems is being developed, based on an integrated, life-cycle, approach to commissioning and performance monitoring. The tool uses component-level HVAC equipment models implemented in the SPARK equation-based simulation environment. The models are configured using design information and component manufacturers{\textquoteright} data and then fine-tuned to match the actual performance of the equipment by using data measured during functional tests of the sort using in commissioning. This paper presents the results of field tests of mixing box and VAV fan system models in an experimental facility and a commercial office building. The models were found to be capable of representing the performance of correctly operating mixing box and VAV fan systems and detecting several types of incorrect operation.

}, author = {Peng Xu and Philip Haves} } @proceedings {297, title = {HVAC Component Data Modeling Using Industry Foundation Classes}, journal = {System Simulation in Buildings {\textquoteright}02}, year = {2002}, month = {12/2002}, address = {Li{\`e}ge, Belgium}, abstract = {

The Industry Foundation Classes (IFC) object data model of buildings is being developed by the International Alliance for Interoperability (IAI). The aim is to support data sharing and exchange in the building and construction industry across the life-cycle of a building.

This paper describes a number of aspects of a major extension of the HVAC part of the IFC data model. First is the introduction of a more generic approach for handling HVAC components. This includes type information, which corresponds to catalog data, occurrence information, which defines item-specific attributes such as location and connectivity, and performance history information, which documents the actual performance of the component instance over time. Other IFC model enhancements include an extension of the connectivity model used to specify how components forming a system can be traversed and the introduction of time-based data streams.

This paper includes examples of models of particular types of HVAC components, such as boilers and actuators, with all attributes included in the definitions. The paper concludes by describing the on-going process of model testing, implementation and integration into the complete IFC model and how the model can be used by software developers to support interoperability between HVAC-oriented design and analysis tools.

}, author = {Vladimir Bazjanac and James Forester and Philip Haves and Darko Sucic and Peng Xu} } @proceedings {300, title = {The Integration of Engineering and Architecture: a Perspective on Natural Ventilation for the new San Francisco Federal Building}, journal = {2002 ACEEE Summer Study on Energy Efficiency in Buildings}, year = {2002}, month = {08/2002}, address = {Asilomar, California, USA}, abstract = {

A description of the in-progress design of a new Federal Office Building for San Francisco is used to illustrate a number of issues arising in the design of large, naturally ventilated office buildings. These issues include the need for an integrated approach to design involving the architects, mechanical and structural engineers, lighting designers and specialist simulation modelers. In particular, the use of natural ventilation, and the avoidance of air-conditioning, depends on the high degree of exposed thermal mass made possible by the structural scheme and by the minimization of solar heat gains while maintaining the good daylighting that results from optimization of the fa{\c c}ade. Another issue was the need for a radical change in interior space planning in order to enhance the natural ventilation; all the individual enclosed offices are located along the central spine of each floorplate rather than at the perimeter. The role of integration in deterring the undermining of the design through value engineering is discussed. The comfort criteria for the building were established based on the recent extension to the ASHRAE comfort standard based on the adaptive model for naturally ventilated buildings. The building energy simulation program EnergyPlus was used to compare the performance of different natural ventilation strategies. The results indicate that, in the San Francisco climate, wind-driven ventilation provides sufficient nocturnal cooling to maintain comfortable conditions and that external chimneys do not provide significant additional ventilation at times when it when it would be beneficial.

}, author = {Erin McConahey and Philip Haves and Tim Chirst} } @proceedings {298, title = {Non-Linear Recursive Parameter Estimation Applied to Fault Detection and Diagnosis in Real Buildings}, journal = {System Simulation in Buildings {\textquoteright}02}, year = {2002}, month = {12/2002}, address = {Li{\`e}ge, Belgium}, author = {Richard A. Buswell and Philip Haves and Tim I. Salsbury and Jonathan A. Wright} } @article {308, title = {Analysis of an Information Monitoring and Diagnostic System to Improve Building Operations}, journal = {Energy and Buildings}, volume = {33}, year = {2001}, month = {10/2001}, pages = {783-792}, chapter = {783}, abstract = {

This paper discusses a demonstration of a technology to address the problem that buildings do not perform as well as anticipated during design. We partnered with an innovative building operator to evaluate a prototype information monitoring and diagnostic system (IMDS). The IMDS consists of a set of high-quality sensors, data acquisition software and hardware, and data visualization software including a web-based remote access system, that can be used to identify control problems and equipment faults. The information system allowed the operators to make more effective use of the building control system and freeing up time to take care of other tenant needs. They report observing significant improvements in building comfort, potentially improving tenant health and productivity. The reduction in the labor costs to operate the building is about US$ 20,000 per year, which alone could pay for the information system in about 5 years. A control system retrofit based on findings from the information system is expected to reduce energy use by 20\% over the next year, worth over US$ 30,000 per year in energy cost savings. The operators are recommending that similar technology be adopted in other buildings.

}, keywords = {building control system, building operation, imds}, doi = {10.1016/S0378-7788(01)00068-8}, author = {Mary Ann Piette and Satkartar T. Khalsa and Philip Haves} } @proceedings {305, title = {Comparison of Chiller Models for use in Model-Based Fault Detection}, journal = {International Conference for Enhancing Building Operations}, year = {2001}, month = {07/2001}, address = {Austin, TX}, abstract = {

Selecting the model is an important and essential step in model based fault detection and diagnosis (FDD). Factors that are considered in evaluating a model include accuracy, training data requirements, calibration effort, generality, and computational requirements. The objective of this study was to evaluate different modeling approaches for their applicability to model based FDD of vapor compression chillers. Three different models were studied: the Gordon and Ng Universal Chiller model (2nd generation) and a modified version of the ASHRAE Primary Toolkit model, which are both based on first principles, and the DOE-2 chiller model, as implemented in CoolToolsTM, which is empirical. The models were compared in terms of their ability to reproduce the observed performance of an older, centrifugal chiller operating in a commercial office building and a newer centrifugal chiller in a laboratory. All three models displayed similar levels of accuracy. Of the first principles models, the Gordon-Ng model has the advantage of being linear in the parameters, which allows more robust parameter estimation methods to be used and facilitates estimation of the uncertainty in the parameter values. The ASHRAE Toolkit Model may have advantages when refrigerant temperature measurements are also available. The DOE-2 model can be expected to have advantages when very limited data are available to calibrate the model, as long as one of the previously identified models in the CoolTools library matches the performance of the chiller in question.

}, author = {Priya Sreedharan and Philip Haves} } @proceedings {306, title = {Demand Relief and Weather Sensitivity in Large California Commercial Buildings}, journal = {International Conference for Enhancing Building Operations}, year = {2001}, month = {07/2001}, address = {Austin, TX}, abstract = {

A great deal of research has examined the weather sensitivity of energy consumption in commercial buildings; however, the recent power crisis in California has given greater importance to peak demand. Several new loadshedding programs have been implemented or are under consideration. Historically, the target customers have been large industrial users who can reduce the equivalent load of several large office buildings. While the individual load reduction from an individual office building may be less significant, there is ample opportunity for load reduction in this area. The load reduction programs and incentives for industrial customers may not be suitable for commercial building owners. In particular, industrial customers are likely to have little variation in load from day to day. Thus a robust baseline accounting for weather variability is required to provide building owners with realistic targets that will encourage them to participate in load shedding programs.

}, author = {Satkartar Kinney and Mary Ann Piette and Lixing Gu and Philip Haves} } @article {312, title = {Efficient Solution Strategies for Building Energy System Simulation}, journal = {Energy and Buildings}, volume = {33}, year = {2001}, month = {04/2001}, pages = {309-317}, chapter = {309}, abstract = {

The efficiencies of methods employed in solution of building simulation models are considered and compared by means of benchmark testing. Direct comparisons between the Simulation Problem Analysis and Research Kernel (SPARK) and the HVACSIM+ programs are presented, as are results for SPARK versus conventional and sparse matrix methods. An indirect comparison between SPARK and the IDA program is carried out by solving one of the benchmark test suite problems using the sparse methods employed in that program. The test suite consisted of two problems chosen to span the range of expected performance advantage. SPARK execution times versus problem size are compared to those obtained with conventional and sparse matrix implementations of these problems. Then, to see if the results of these limiting cases extend to actual problems in building simulation, a detailed control system for a heating, ventilating and air conditioning (HVAC) system is simulated with and without the use of SPARK cut set reduction. Execution times for the reduced and non-reduced SPARK models are compared with those for an HVACSIM+ model of the same system. Results show that the graph-theoretic techniques employed in SPARK offer significant speed advantages over the other methods for significantly reducible problems and that by using sparse methods in combination with graph-theoretic methods even problem portions with little reduction potential can be solved efficiently.

}, keywords = {building energy systems, computational efficiency, graph theory applications, hvac simulation, hvacsim+ models, spark models}, doi = {10.1016/S0378-7788(00)00113-4}, author = {Edward F. Sowell and Philip Haves} } @proceedings {50, title = {GenOpt - A Generic Optimization Program}, journal = {Proc. of the 7th IBPSA Conference}, volume = {I}, year = {2001}, pages = {601-608}, address = {Rio de Janeiro}, abstract = {

The potential offered by computer simulation is often not realized: Due to the interaction of system variables, simulation users rarely know how to choose input parameter settings that lead to optimal performance of a given system. Thus, a program called GenOpt{\textregistered} that automatically determines optimal parameter settings has been developed.

GenOpt is a generic optimization program. It minimizes an objective function with respect to multiple parameters. The objective function is evaluated by a simulation program that is iteratively called by GenOpt. In thermal building simulation {\textemdash} which is the main target of GenOpt {\textemdash} the simulation program usually has text-based I/O. The paper shows how GenOpt{\textquoteright}s simulation program interface allows the coupling of any simulation program with text based I/O by simply editing a configuration file, avoiding code modification of the simulation program. By using object-oriented programming, a high-level interface for adding minimization algorithms to GenOpt{\textquoteright}s library has been developed. We show how the algorithm interface separates the minimization algorithms and GenOpt{\textquoteright}s kernel, which allows implementing additional algorithms without being familiar with the kernel or having to recompile it. The algorithms can access utility classes that are commonly used for minimization, such as optimality check, line-search, etc.

GenOpt has successfully solved various optimization problems in thermal building simulation. We show an example of minimizing source energy consumption of an office building using EnergyPlus, and of minimizing auxiliary electric energy of a solar domestic hot water system using TRNSYS. For both examples, the time required to set up the optimization was less than one hour, and the energy savings are about 15\%, together with better daylighting usage or lower investment costs, respectively.

}, url = {http://www.ibpsa.org/proceedings/BS2001/BS01_0601_608.pdf}, author = {Michael Wetter}, editor = {Roberto Lamberts and Cezar O. R. Negr{\~a}o and Jan Hensen} } @article {303, title = {A Nodal Model for Displacement Ventilation and Chilled Ceiling Systems in Office Spaces}, journal = {Building and Environment}, volume = {36}, year = {2001}, month = {07/2001}, pages = {753-762}, chapter = {753}, abstract = {

A nodal model has been developed to represent room heat transfer in displacement ventilation and chilled ceiling systems. The model uses precalculated air flow rates to predict the air temperature distribution and the division of the cooling load between the ventilation air and the chilled ceiling. The air movements in the plumes and the rest of the room are represented separately using a network of ten air nodes. The values of the capacity rate parameters are calculated by solving the heat and mass balance equations for each node using measured temperatures as inputs. Correlations between parameter values for a range of cooling loads and supply air flow rates are presented.

}, keywords = {Chilled ceilings, commercial buildings, Displacement ventilation, energy, Heat Transfer, Nodal model, simulation}, doi = {10.1016/S0360-1323(00)00067-6}, url = {http://www.ibpsa.org/proceedings/BS1999/BS99_D-05.pdf}, author = {Simon J. Rees and Philip Haves} } @article {307, title = {Numerical Investigation of Transient Buoyant Flow in a Room with a Displacement Ventilation and Chilled Ceiling System}, journal = {International Journal of Heat and Mass Transfer}, volume = {44}, year = {2001}, month = {08/2001}, pages = {3067-3080}, chapter = {3067}, abstract = {

The air flow in the office ventilation system known as displacement ventilation is dominated by a gravity current from the inlet and buoyant plumes above internal heat sources. Calculations of the flow and heat transfer in a typical office room have been made for this type of ventilation system used in conjunction with chilled ceiling panels. These calculations have been made in parallel with full size test chamber experiments. It has been found that with higher values of internal load (45 and 72 W m-2 of floor area) the flow becomes quasi-periodic in nature. Complex lateral oscillations are seen in the plumes above the heat sources which impinge on the ceiling and induce significant recirculating flows in the room. The frequency spectra of the transient calculations show good agreement with those of the experimental results. Comparison is also made between calculated mean room air speeds and temperature profiles and measured values.

}, doi = {10.1016/S0017-9310(00)00348-3}, url = {http://www.sciencedirect.com/science/article/pii/S0017931000003483}, author = {Simon J. Rees and James J. McGuirk and Philip Haves} } @conference {1850, title = {Strategies for Coupling Energy Simulation Programs and Computational Fluid Dynamics Programs}, booktitle = {Building Sim 2001}, volume = {1}, year = {2001}, month = {08/2001}, pages = {59-66}, address = {Rio de Janeiro, Brazil}, abstract = {

Energy simulation (ES) and computational fluid dynamics (CFD) can play important roles in building design by providing complementary information about the buildings{\textquoteright} environmental performance. However, separate applications of ES and CFD are usually unable to give an accurate prediction of building performance due to the assumptions involved in the separate calculations. Integration of ES and CFD eliminates many of these assumptions since the information provided by the models is complementary. Several different approaches to integrating ES and CFD are described. In order to bridge the discontinuities of time-scale, spatial resolution and computing speed between ES and CFD programs, a staged coupling strategy for different problems is proposed. The paper illustrates a typical dynamic coupling process by means of an example implemented using the EnergyPlus and MIT-CFD programs.

}, author = {Zhiqiang Zhai and Qingyan Chen and Joseph H. Klems and Philip Haves} } @proceedings {304, title = {Use of Whole Building Simulation in On-Line Performance Assessment: Modeling and Implementation Issues}, journal = {Building Simulation {\textquoteright}01}, year = {2001}, month = {08/2001}, address = {Rio de Janeiro}, abstract = {

The application of model-based performance assessment at the whole building level is explored. The information requirements for a simulation to predict the actual performance of a particular real building, as opposed to estimating the impact of design options, are addressed with particular attention to common sources of input error and important deficiencies in most simulation models. The role of calibrated simulations is discussed. The communication requirements for passive monitoring and active testing are identified and the possibilities for using control system communications protocols to link on-line simulation and energy management and control systems are discussed. The potential of simulation programs to act as "plug-and-play" components on building control networks is discussed.

}, author = {Philip Haves and Tim I. Salsbury and David Claridge and Mingsheng Liu} } @proceedings {310, title = {Better IAQ Through Integrating Design Tools For The HVAC Industry}, journal = {Healthy Buildings 2000}, year = {2000}, month = {08/2000}, address = {Espoo, Finland}, abstract = {

There is currently no effective combination of interoperable design tools to cover all critical aspects of the HVAC design process. Existing design tools are separately available, but require expertise and operating time that is beyond the scope of a normal design project. For example, energy analysis and computational fluid dynamics (CFD) tools are not used in practical design, leading to poor indoor air quality and/or unnecessary energy consumption in buildings.

A prototype integrated software tool for demonstration, process mapping and proof-of-concept purposes was developed under a new international, Finland/USA jointly funded development project BildIT. Individual design tools were simplified and adapted to specific applications and also integrated so that they can be used in a timely and effective manner by the designer. The core of the prototype linked together an architectural CAD system, a 3D space model, a CFD program and a building energy simulation program and it utilises real product data from manufacturer{\textquoteright}s software. Also the complex building design, construction, maintenance and retrofit processes were mapped to get a template for the structure of the integrated design tool.

}, author = {Tuomas Laine and Risto Kosonen and Kim Hagstr{\"o}m and Panu Mustakallio and De-Wei Yin and Philip Haves and Qingyan Chen} } @article {422, title = {Building simulation: an overview of development and information sources}, journal = {Building and Environment}, volume = {35}, year = {2000}, month = {05/2000}, pages = {347-361}, type = {Review Article}, chapter = {347}, abstract = {

We review the state-of-the-art on the development and application of computer-aided building simulation by addressing some crucial questions in the field. Although the answers are not intended to be comprehensive, they are sufficiently varied to provide an overview ranging from the historical and technical development to choosing a suitable simulation program and performing building simulation. Popular icons of major interested agencies and simulation tools and key information sources are highlighted. Future trends in the design and operation of energy-efficient {\textquoteleft}green{\textquoteright} buildings are briefly described.

}, keywords = {building simulation}, doi = {10.1016/S0360-1323(99)00023-2}, author = {Tianzhen Hong and Siaw K. Chou and T.Y. Bong} } @article {313, title = {Comparison of Peak Load Predictions and Treatment of Solar Gains in the Admittance and Heat Balance Load Calculation Procedures}, journal = {Building Services Engineering Research \& Technology}, volume = {21}, year = {2000}, abstract = {Calculation of design cooling loads is of critical concern to designers of HVAC systems. The work reported here has been carried out under a joint ASHRAE-CIBSE research project to compare design cooling calculation methods. Peak cooling loads predicted by the ASHRAE heat balance method are compared with those predicted by a number of implementations of the admittance method using different window models. The results presented show the general trends in overprediction or underprediction of peak load. Particular attention is given to different window modelling practices. The performance of the methods is explained in terms of some of the underlying assumptions in the window models, and by reference to specific inter-model comparisons.}, doi = {10.1177/014362440002100207}, url = {http://bse.sagepub.com/content/21/2/125}, author = {Simon J. Rees and Jeffrey D. Spitler and Michael J. Holmes and Philip Haves} } @proceedings {309, title = {Model-based Performance Monitoring: Review of Diagnostic Methods and Chiller Case Study}, journal = {ACEEE Summer School}, year = {2000}, month = {08/2000}, address = {Asilomar, California, USA}, abstract = {

The paper commences by reviewing the variety of technical approaches to the problem of detecting and diagnosing faulty operation in order to improve the actual performance of buildings. The review covers manual and automated methods, active testing and passive monitoring, the different classes of models used in fault detection, and methods of diagnosis. The process of model-based fault detection is then illustrated by describing the use of relatively simple empirical models of chiller energy performance to monitor equipment degradation and control problems. The CoolTools{\texttrademark} chiller model identification package is used to fit the DOE-2 chiller model to on-site measurements from a building instrumented with high quality sensors. The need for simple algorithms to reject transient data, detect power surges and identify control problems is discussed, as is the use of energy balance checks to detect sensor problems. The accuracy with which the chiller model can be expected to predict performance is assessed from the goodness of fit obtained and the implications for fault detection sensitivity and sensor accuracy requirements are discussed. A case study is described in which the model was applied retroactively to high-quality data collected in a San Francisco office building as part of a related project (Piette et al. 1999).

}, author = {Philip Haves and Satkartar T. Khalsa} } @article {314, title = {Qualitative Comparison of North American and U.K. Cooling Load Calculation Procedures}, journal = {International Journal of Heating, Ventilating, Air-Conditioning and Refrigeration Research}, volume = {6}, year = {2000}, pages = {75-99}, chapter = {75}, abstract = {

A qualitative comparison is presented between three current North American and U.K. design cooling load calculation methods. The methods compared are the ASHRAE Heat Balance Method, the Radiant Time Series Method and the Admittance Method, used in the U.K. The methods are compared and contrasted in terms of their overall structure. In order to generate the values of the 24 hourly cooling loads, comparison was also made in terms of the processing of the input data and the solution of the equations required. Specific comparisons are made between the approximations used by the three calculation methods to model some of the principal heat transfer mechanisms. Conclusions are drawn regarding the ability of the simplified methods to correctly predict peak-cooling loads compared to the Heat Balance Method predictions. Comment is also made on the potential for developing similar approaches to cooling load calculation in the U.K. and North America in the future.

}, doi = {10.1080/10789669.2000.10391251}, author = {Simon J. Rees and Jeffrey D. Spitler and Morris G. Davies and Philip Haves} } @proceedings {311, title = {Use of an Information Monitoring and Diagnostic System for Commissioning and Ongoing Operations}, journal = {8th National Conference on Building Commissioning PECI}, year = {2000}, month = {05/2000}, abstract = {This paper discusses a demonstration of a technology to address the problem that buildings do not perform as well as anticipated during design. We partnered with an innovative building operator to evaluate a prototype Information Monitoring and Diagnostic System (IMDS). The IMDS consists of a set of high-quality sensors, data acquisition software and hardware, and data visualization software, including a web-based remote access system that can be used to identify control problems and equipment faults. The IMDS allowed the operators to make more effective use of the control system, freeing up time to take care of other tenant needs. The operators report observing significant improvements in building comfort, potentially improving tenant health and productivity. Reduction in hours to operate the building are worth about $20,000 per year, which alone could pay for the IMDS in about five years. A control system retrofit based on findings from the IMDS is expected to reduce energy use by 20 percent over the next year, worth over $30,000 per year in energy cost savings. The operators recommend that similar technology be adopted in other buildings. While the current IMDS is oriented toward manual, human-based diagnostic techniques, we also evaluated automated diagnostic techniques. Strategies for utilizing results from this demonstration to influence commercial building performance monitoring for commissioning and operations will be discussed. Background}, url = {http://imds.lbl.gov/pubs/paper383.pdf}, author = {Mary Ann Piette and Satkartar T. Khalsa and Philip Haves} } @article {423, title = {A design day for building load and energy estimation}, journal = {Building and Environment}, volume = {34}, year = {1999}, month = {07/1999}, pages = {469-477}, chapter = {469}, abstract = {

We describe how a design day for building energy performance simulation can be selected from a typical meteorological year of a location. The advantages of the design day weather file are its simplicity and flexibility in use with simulation programs. The design day is selected using a weather parameter comprising the daily average dry bulb temperature and total solar insolation. The selection criterion addresses the balance between the need to minimise the part-load performance of the air-conditioning systems and plants and the number of hours of load not met. To validate the versatility of the design day weather file, we compare simulation results of the peak load and load profile of a building obtained from the DOE-2.1E code and a specially developed load estimation program, PEAKLOAD. PEAKLOAD is developed using the transfer function method and ASHRAE databases. Comparative results are in good agreement, indicating that a design day thus selected can be used when quick answers are required and simulations using a TMY file cannot be easily done or justified.

}, keywords = {building simulation, design day, doe-2, peak load calculation, weather data}, doi = {10.1016/S0360-1323(98)00035-3}, author = {Tianzhen Hong and Siaw K. Chou and T.Y. Bong} } @proceedings {316, title = {A Nodal Model for Displacement Ventilation and Chilled Ceiling Systems in Office Spaces}, journal = {Building Simulation {\textquoteright}99}, year = {1999}, month = {09/1999}, address = {Kyoto, Japan}, abstract = {

A nodal model has been developed to represent room heat transfer in displacement ventilation and chilled ceiling systems. The model uses precalculated air flow rates to predict the air temperature distribution and the division of the cooling load between the ventilation air and the chilled ceiling. The air movements in the plumes and the rest of the room are rep- resented separately using a network of ten air nodes. The values of the capacity rate parameters are calculated by solving the heat and mass balance equations for each node using measured temperatures as inputs. Correlations between parameter values for a range of cooling loads and supply air flow rates are presented.

}, url = {http://www.ibpsa.org/proceedings/BS1999/BS99_D-05.pdf}, author = {Simon J. Rees and Philip Haves} } @proceedings {315, title = {Numerical Performance of a Graph-Theoretic HVAC Simulation Program}, journal = {Building Simulation {\textquoteright}99}, year = {1999}, month = {09/1999}, address = {Kyoto, Japan}, abstract = {The Simulation Problem Analysis and Research Kernel (SPARK) uses graph-theoretic techniques to match equations to variables and build computational graphs, yielding solution sequences indicated by needed data flow. Additionally, the problem graph is decomposed into strongly connected components, thus reducing the size of simultaneous equation sets, and small cut sets are determined, thereby reducing the number of iteration variables needed to solve each equation set. The improvement in computational efficiency produced by this graph theoretic preprocessing depends on the nature of the problem. The paper explores the improvement one might expect in practice in three ways. First, two problems chosen to span the range of performance are studied and some of the factors determining the performance are identified and discussed. The problem selected to exhibit a large improvement consists of a set of sparsely coupled non-linear equations. The problem selected to represent the other end of the performance spectrum is a set of equations obtained by discretizing Laplace{\textquoteright}s equation in two dimensions, e.g. a heat conduction problem. Execution time versus problem size is compared to that obtained with sparse matrix implementations of the same problems. Then, to see if the results of these somewhat contrived limiting cases extend to actual problems in building simulation, a detailed control system model of a six- zone VAV HVAC system is simulated with and without the use of cut set reduction. Execution times are compared between the reduced and non-reduced SPARK models, and with those from an HVACSIM+ model of the same system.}, url = {http://www.ibpsa.org/proceedings/BS1999/BS99_A-05.pdf}, author = {Edward F. Sowell and Philip Haves} } @proceedings {318, title = {The application of Problem Reduction Techniques Based on Graph Theory to the Simulation of Non-Linear Continuous Systems}, journal = {EUROSIM{\textquoteright}98}, year = {1998}, pages = {pp. 203-207}, address = {Manchester, UK}, author = {Philip Haves and Edward F. Sowell} } @article {320, title = {Comparison of North American and U.K. Cooling Load Calculation Procedures - Methodology}, journal = {ASHRAE Transactions}, volume = {104}, year = {1998}, pages = {47-61}, chapter = {47}, abstract = {This paper describes the methodology used in a quanti- tative comparison between the current North American and United Kingdom cooling load calculation methods. Three calculation methods have been tested as part of a joint ASHRAE/CIBSE research project: the ASHRAE heat balance method and radiant time series method and the admittance method, used in the U.K. A companion paper (Rees et al.1998) describes the results of the study. The quantitative comparison is primarily organized as a parametric study{\textemdash}each building zone/weather day combination compared may be thought of as a combination of various parameters, e.g., exterior wall type, roof type, glazing area, etc. Specifically, this paper describes the overall organization of the study, the parameters and parameter levels that can be varied, and the tools developed to create input files, automate the load calculations, and extract the results. A brief descrip- tion of the cooling load calculation procedure implementa- tions is also given. The methodology presented and the tools described could also be used to make comparisons between other calculation methods.}, author = {Jeffrey D. Spitler and Simon J. Rees and Philip Haves} } @article {321, title = {Comparison of North American and U.K. Cooling Load Calculation Procedures - Results}, journal = {ASHRAE Transactions}, volume = {104}, year = {1998}, pages = {36-46}, chapter = {36}, abstract = {Calculation of design cooling loads is of critical concern to designers of HVAC systems. The work reported here has been carried out under a joint ASHRAE/CIBSE research project to compare design cooling calculation methods. Three calculation methods have been tested, the ASHRAE heat balance method and radiant time series method, and the admit- tance method, used in the U.K. The results presented in this paper show the general trends in over/underprediction of peak load in the simplified methods compared to the heat balance method. The performance of the simplified methods is explained in terms of some of the underlying assumptions in the methods and by reference to specific examples.}, author = {Simon J. Rees and Jeffrey D. Spitler and Philip Haves} } @proceedings {317, title = {Component-Based and Equation-Based Solvers for HVAC Simulation: a Comparison of HVACSIM+ and SPARK}, journal = {System Simulation in Buildings {\textquoteright}98}, year = {1998}, month = {12/98}, address = {Li{\`e}ge, Belgium}, author = {Philip Haves and Edward F. Sowell} } @article {424, title = {Outdoor synthetic temperature for the calculation of space heating load}, journal = {Energy and Buildings}, volume = {28}, year = {1998}, month = {1998}, pages = {269-277}, type = {Research Article}, abstract = {

Methods to select the outdoor design temperature (ODT) for heating load calculation specified in current design codes in different countries are firstly discussed. Then a new method namely Stochastic Analysis is presented to determine the outdoor synthetic temperature (OST), which fully considers the randomness of weather and internal casual gains, and the thermal performance of buildings. The concept of OST enables the design of space heating system to be the trade-off between economics and risk. Finally, case studies of the influence of different building components on OST of a residential room in Beijing have been studied, which shows that OST depends upon building structures as well as weather conditions. It is recommended that OST rather than ODT should be employed in heating load calculation hence, sizing equipment for space heating systems.

}, keywords = {heating load calculation, outdoor design conditions, residential buildings, stochastic analysis, thermal performance of buildings}, doi = {10.1016/S0378-7788(98)00013-9}, author = {Tianzhen Hong and Yi Jiang} } @article {319, title = {A Standard Simulation Testbed for the Evaluation of Control Algorithms \& Strategies}, journal = {ASHRAE Transactions}, volume = {104}, year = {1998}, abstract = {

This paper, which reports the results of ASHRAE Research Project 825, describes the development of a set of tools and supporting data to facilitate the evaluation of HVAC control algorithms and strategies using computer simulation. The tools consist of a documented set of component models for use in two component-based HVAC simulation programs. New models have been developed to enable explicit simulation of flow rates and pressure drops in ventilation systems, particularly variable-air-volume (VAV) systems, and detailed simulation of algorithms and strategies used in HVAC control systems. A mixed-use building equipped with a VAV HVAC system has been extensively documented, and a detailed model of the fabric, mechanical equipment, and controls has been produced in order to illustrate the capabilities and use of the tools. Values for the parameters in the component models describing the fabric and mechanical equipment are based on construction drawings, manufacturer{\textquoteright}s specifications, surveys, and measurements. Detailed models of the strategies for fan control, supply air temperature control, and room temperature control were developed from the controls manufacturer{\textquoteright}s technical information and the configuration of the actual control system. A simulation model of the whole building was then assembled from the models of the fabric, mechanical equipment, and controls. Results obtained by exercising the test bed in order to demonstrate its use in evaluating the performance of interacting control loops are presented. The paper concludes by discussing possible applications and extensions of the test bed.

}, author = {Philip Haves and Leslie K. Norford and Mark DeSimone} } @proceedings {322, title = {Fault Modelling in Component-based HVAC Simulation}, journal = {Building Simulation {\textquoteright}97}, year = {1997}, month = {09/1997}, address = {Prague, Czech Republic}, abstract = {Models of faulty components or processes may either be used on-line as part of a fault detec- tion and diagnosis (FDD) system or may be used in simulations to train or test FDD procedures. Some faults may be modelled by choosing suit- able values of the parameters of fault free models, whereas other faults require specific extensions to fault free models. An example of the modelling of various faults in a cooling coil subsystem is pre- sented and different methods of using simulation in testing and training are discussed.}, url = {http://www.ibpsa.org/proceedings/BS1997/BS97_P101.pdf}, author = {Philip Haves} } @article {426, title = {IISABRE: An integrated building simulation environment}, journal = {Building and Environment}, volume = {32}, year = {1997}, month = {1997}, pages = {219-224}, type = {Research Article}, abstract = {

An integrated building simulation environment, IISABRE, is introduced. IISABRE consists of CABD, BTP and IISPAM. CABD is an AutoCAD-based building descriptor enabling users to draw a building and define information. Some design tools are built into CABD, and a STEP-based building database can be generated, which provides an open mechanism to share the building database with other programs. BTP is a program for the detailed dynamic simulation of building thermal performance. With a PC 486DX50 (8M RAM) running in MS-Windows 3.11, BTP needs about 40 minutes to calculate the annual hourly energy demand for a building with 20 zones. IISPAM is a knowledge-based system for translating the STEP-based building database into ASCII-based data files for BTP. IISABRE can be widely employed in the field of building environmental engineering in order to improve the energy efficiency of buildings and the thermal comfort of the indoor environment.

}, keywords = {btp, building simulation, dest, energy performance, gui}, doi = {10.1016/S0360-1323(96)00057-1}, author = {Tianzhen Hong and Yi Jiang} } @proceedings {323, title = {A Model-Based Approach to the Commissioning of HVAC Systems}, journal = {CLIMA 2000}, year = {1997}, month = {08/1997}, address = {Brussles, Belgium}, author = {Richard A. Buswell and Philip Haves and Tim I. Salsbury} } @article {425, title = {A new multizone model for simulation of building thermal performance}, journal = {Building and Environment}, volume = {32}, year = {1997}, month = {1997}, pages = {123-128}, type = {Research Article}, abstract = {

A new multizone model which is an improvement on the state space model is presented, which is potentially more efficient in the simulation of large scale buildings than other methods such as finite difference, transfer functions, or finite volume. The modeling philosophy is firstly discussed. Then the principle and algorithm of the new model are described. Finally, a PC based program BTP developed based on state-of-the-art modeling strategy reveals its applicability with fast calculation speed and satisfactory accuracy in the modeling of building energy performance.

}, doi = {10.1016/S0360-1323(96)00045-5}, author = {Tianzhen Hong and Yi Jiang} } @article {324, title = {Condition Monitoring in HVAC Subsystems using First Principles Models}, journal = {ASHRAE Transactions}, volume = {102}, year = {1996}, author = {Philip Haves and Tim I. Salsbury and Jonathan A. Wright} } @proceedings {325, title = {Development and Testing of a Prototype Tool for HVAC Control System Commissioning}, journal = {ASHRAE Transactions}, volume = {102}, year = {1996}, edition = {1}, address = {Atlanta, GA}, abstract = {

Describes a set of automated tests for use in commissioning the controls associated with coils and mixing boxes in air-handling units. The test procedures were developed using a computer simulation of an office building air conditioning system and were verified by manual testing in real buildings. A prototype automated commissioning system was then evaluated in blind tests on a large air conditioning test rig. Concludes that automated commissioning has the potential to reduce the cost and increase the thoroughness of HVAC controls commissioning. A prototype commissioning tool is under development based on the described approach.

}, keywords = {air conditioning, automatic, commissioning, controls, prototypes, testing, year 1996}, author = {Philip Haves and Jorgensen, D.R. and Tim I. Salsbury and Arthur L. Dexter} } @proceedings {328, title = {Detailed Modelling and Simulation of a VAV Air-Conditioning System}, journal = {Building Simulation {\textquoteright}95}, year = {1995}, month = {08/1995}, address = {Madison, WI}, abstract = {The paper describes a component-based dynamic simulation of a variable air volume (VAV) airconditioning system. The model is based closely on the design of one floor of a real commercial office building in London. The model includes an air handling unit and a duct system incorporating pressure-independent VAV boxes. The paper describes the simulation environment used to test control systems and to develop fault detection and diagnosis procedures and presents results of simulations that illustrate how the simulation can be used to study the interactions between control loops.}, url = {http://www.ibpsa.org/proceedings/BS1995/BS95_056_63.pdf}, author = {Philip Haves} } @proceedings {327, title = {A Fault Detection and Diagnosis Method Based on First Principles Models and Expert Rules}, journal = {Tsinghua HVAC-95}, year = {1995}, month = {09/1995}, address = {Bejing, China}, author = {Tim I. Salsbury and Philip Haves and Jonathan A. Wright} } @article {2577, title = {Integrated building design system}, journal = {HV\&AC, in Chinese}, year = {1995}, month = {1995}, author = {Yi Jiang and Tianzhen Hong} } @proceedings {329, title = {A Model of a Displacement Ventilation/Chilled Ceiling Cooling System Suitable for Annual Energy Simulation}, journal = {Building Simulation {\textquoteright}95}, year = {1995}, month = {08/1995}, address = {Madison, WI}, author = {Simon J. Rees and Philip Haves} } @proceedings {326, title = {Modelling and Simulation of Low Energy Cooling Systems}, journal = {Tsinghua HVAC-95}, year = {1995}, month = {09/1995}, address = {Bejing, China}, author = {Philip Haves and Simon J. Rees and Harrington, L.} } @conference {2627, title = {Prediction of building thermal performance under random conditions}, booktitle = {TSINGHUA-HVAC-{\textquoteright}95}, year = {1995}, month = {1995}, address = {Beijing, China}, author = {Tianzhen Hong and Yi Jiang} } @article {427, title = {Stochastic weather model for building HVAC systems}, journal = {Building and Environment}, volume = {30}, year = {1995}, month = {1995}, pages = {521-532}, type = {Research Article}, abstract = {

The weather is a multi-dimensional stochastic process; the traditional typical or standard meteorological year is not enough to describe the random behaviour of weather. The model presented in this paper is based on the vector auto-regressive (VAR) time series method. From the validation results, it can be seen that the stochastic weather model is essential to describe real climate behaviour, and the accuracy obtained is sufficient for the application of the stochastic weather model in the simulation and stochastic analysis of building HVAC systems.

}, doi = {10.1016/0360-1323(95)00007-S}, author = {Tianzhen Hong and Yi Jiang} } @proceedings {330, title = {Component-Based Modelling of VAV Systems}, journal = {System Simulation in Buildings {\textquoteright}94}, year = {1994}, month = {12/1994}, address = {Li{\`e}ge, Belgium}, author = {Philip Haves} } @article {335, title = {Design, Construction and Commissioning of Building Emulators for EMCS Applications}, journal = {ASHRAE Transactions}, volume = {100}, year = {1994}, author = {Shengwei Wang and Philip Haves and Pierre Nusgens} } @article {332, title = {Evaluating the Performance of Building Control Systems using an Emulator}, journal = {Building Services Engineering Research \& Technology}, volume = {15}, year = {1994}, abstract = {The control performance of an air-conditioning system is assessed using a qualitative method of evaluation. Fuzzy logic is used to relate performance criteria expressed in the form of IF-THEN rules to quantitative measures of energy consumption, discomfort, and maintenance costs. Test data were generated using an emulator consisting of a real-time simulation of the building shell and HVAC plant, together with a hardware interface that connects the simulation to commercial control equipment. Two case studies are presented. In the first, the effect of changing the strategy used to determine the zone temperature set-points is evaluated using {\textquoteright}expert rules{\textquoteright}, generated by a hypothetical facilities manager. In the second case study, the effect of varying the tuning parameters of the control system is evaluated using two sets of rules assumed to represent the differing perspectives of a facilities manager and a control engineer.}, doi = {10.1177/014362449401500302}, url = {http://bse.sagepub.com/content/15/3.toc}, author = {Arthur L. Dexter and Philip Haves} } @proceedings {333, title = {Fault Detection in Air-Conditioning Systems Using A.I. Techniques}, journal = {BEP{\textquoteright}94}, year = {1994}, address = {York, England}, author = {Arthur L. Dexter and Richard S. Fargus and Philip Haves} } @article {334, title = {Investigation of the Reliability of Building Emulators for Testing Energy Management and Control Systems}, journal = {ASHRAE Transactions}, volume = {100}, year = {1994}, author = {Henk C. Peitsman and Shengwei Wang and Philip Haves and Satu H. K{\"a}rki and Cheol P. Park} } @proceedings {331, title = {Model-Based Approaches to Fault Detection and Diagnosis in Air-Conditioning System}, journal = {System Simulation in Buildings {\textquoteright}94}, year = {1994}, month = {12/1994}, address = {Li{\`e}ge, Belgium}, author = {Mourad Benouarets and Arthur L. Dexter and Richard S. Fargus and Philip Haves and Tim I. Salsbury and Jonathan A. Wright} } @proceedings {336, title = {Automatic Commissioning of HVAC Control Systems}, journal = {CLIMA 2000}, year = {1993}, month = {11/1993}, address = {London, England}, author = {Arthur L. Dexter and Philip Haves and Jorgensen, D.R.} } @proceedings {337, title = {Development of Techniques to Assist in the Commissioning of HVAC Control Systems}, journal = {CIBSE National Conference}, year = {1993}, month = {05/1993}, address = {Manchester, UK}, author = {Arthur L. Dexter and Philip Haves and Jorgensen, D.R.} } @article {428, title = {Stochastic analysis of building thermal processes}, journal = {Building and Environment}, volume = {28}, year = {1993}, month = {1993}, pages = {209-218}, type = {Research Article}, abstract = {

A methodology is presented for investigating the uncertainty properties of the building thermal processes caused by the random behaviour of the meteorological processes and the casual gains. A detailed building thermal model is used with a stochastic weather model and a random casual gain model. The probability distribution of the zone temperature of the building is calculated directly from these models. The overheating risk has been analysed as an example. The probability distribution of the periods when the zone temperature is higher than the demand temperature is calculated. The result shows all the possible situations rather than only a sample as would be obtained by running a normal simulation using given weather data. The influence of different building components on the overheating risk has been studied. The result shows that the most likely component for overheating risk in a residential building in Beijing is the window size. The thermal mass of the internal walls and the placing of windows have little effect on overheating risk.

}, doi = {10.1016/0360-1323(93)90027-Z}, author = {Yi Jiang and Tianzhen Hong} } @conference {2628, title = {Stochastic analysis of overheating risk in buildings}, booktitle = {CLIMA 2000}, year = {1993}, month = {1993}, address = {London, UK}, author = {Yi Jiang and Tianzhen Hong} } @proceedings {338, title = {Climate Change and Passive Cooling in Europe}, journal = {PLEA{\textquoteright}92 Conference}, year = {1992}, address = {Auckland, New Zealand}, author = {Philip Haves and Kenny, G. and Susan Roaf} } @inbook {340, title = {Environmental Control in Energy Efficient Buildings}, booktitle = {Energy Efficient Buildings: A Design Guide}, year = {1992}, publisher = {Blackwell Scientific Publications Ltd}, organization = {Blackwell Scientific Publications Ltd}, address = {Oxford}, isbn = {0470219521}, author = {Philip Haves} } @proceedings {339, title = {Impacts of Climate Change}, journal = {International Energy Agency Future Buildings Forum Workshop on Innovative Cooling}, year = {1992}, month = {05/1992}, address = {Solihull, England}, author = {Mike Hulme and Philip Haves and Boardman, B.} } @proceedings {344, title = {Self-tuning Control with Fuzzy Rule-Based Supervision for HVAC Applications}, journal = {ITAC 91}, year = {1991}, address = {Singapore}, author = {Keck-Voon Ling and Arthur L. Dexter and Geng, G. and Philip Haves} } @article {343, title = {Use of a Building Emulator to Develop Techniques for Improved Commissioning and Control of HVAC Systems}, journal = {ASHRAE Transactions}, volume = {97}, year = {1991}, keywords = {air conditioning, automatic, commissioning, computer programs, controls, energy management, heating, ventilation}, author = {Philip Haves and Arthur L. Dexter and Jorgensen, D.R. and Keck-Voon Ling and Geng, G.} } @proceedings {342, title = {Use of a Building Emulator to Evaluate Control Strategies Implemented in Commercial BEMS}, journal = {Building Environmental Performance {\textquoteright}91}, year = {1991}, month = {04/1991}, address = {Cantebury, England}, author = {Philip Haves and Arthur L. Dexter} } @proceedings {341, title = {Use of Building Emulators to Evaluate the Performance of Building Energy Management Systems}, journal = {Building Simulation {\textquoteright}91}, year = {1991}, month = {08/1991}, pages = {209-213}, address = {Nice, France}, abstract = {

Three complementary approaches may be used in the evaluation of the performance of building control systems-simulation, emulation and field testing. In emulation a real-time simulation of the building and HVAC plant is connected to a real building energy management system (BEMS) via a hardware interface. Emulation has the advantage of allowing controlled, repeatable experiments whilst testing real devices that may contain proprietary algorithms. Building emulators have been developed by the authors in the context of lEA Annex 17, which is concerned with the use of simulation to evaluate the performance of BEMS. The paper discusses different approaches to the design of building emulators and describes the different architectures, hardware and software used by the authors. The problem of evaluating the overall performance of BEMS is discussed and results are presented that illustrate the use of emulators to investigate the influence of the tuning of local loop controls on building performance.

}, author = {Hossein Vaezi-Nejad and E. Hutter and Philip Haves and Arthur L. Dexter and George E. Kelly and Pierre Nusgens and Shengwei Wang} } @proceedings {345, title = {The Influence of Tuning on the Performance of a Building Control System}, journal = {System Simulation in Buildings {\textquoteright}90}, year = {1990}, month = {12/1990}, address = {Li{\`e}ge, Belgium}, author = {Arthur L. Dexter and Philip Haves} } @article {347, title = {A Robust Self-Tuning Controller for HVAC Applications}, journal = {ASHRAE Transactions}, year = {1989}, author = {Arthur L. Dexter and Philip Haves} } @proceedings {346, title = {Simulation of Local Loop Controls}, journal = {Building Simulation 89}, year = {1989}, address = {Vancouver, Canada}, author = {Arthur L. Dexter and Philip Haves} } @article {348, title = {Daylight in Dynamic Thermal Modelling Programs: a Case Study}, journal = {Building Services Engineering Research \& Technology}, volume = {9}, year = {1988}, month = {11/1988}, pages = {183-188}, chapter = {183}, abstract = {

Heating, cooling and lighting energy consumptions in buildings are inter-related, and a model which treats thermal performance and lighting simultaneously is required in order to evaluate the full benefits of daylighting in buildings. A lighting facility has been included in a dynamic building simulation program (SERI-RES) used in the Department of Energy{\textquoteright}s passive solar programme. Interior daylight illuminance is calculated using an extension of the daylight factor method. The lighting usage of various lighting systems is predicted from the daylight illuminance, and the thermal consequences of that lighting use included in the thermal simulation of the building. The applicability of the method described in this paper is not limited to SERI-RES. The method could be incorporated in any building energy analysis program intended for the UK or similar climates.

}, doi = {10.1177/014362448800900406}, author = {Philip Haves and Paul J. Littlefair} } @conference {349, title = {Towards an Environment for HVAC Control System Evaluation}, booktitle = {USER-1 Building Simulation Conference}, series = {European Society for Computer Simulation}, year = {1988}, month = {09/1988}, address = {Ostend, Belgium}, author = {Philip Haves and Trewella, D.} } @proceedings {350, title = {The Application of Simulation to the Evaluation of Building Energy Control Systems}, journal = {UKSC87 Conference}, year = {1987}, address = {Bangor, UK}, author = {Philip Haves} } @article {352, title = {Performance of Roofpond Cooled Residences in U.S. Climate}, journal = {Passive Solar Journal}, volume = {4}, year = {1987}, month = {01/1987}, pages = {265-292}, chapter = {265}, abstract = {

The thermal advantages of a roofpond as an element of a residential cooling system are described. The authors conducted heat transfer experiments at two roofpond residences (RPRs) at Trinity University; the authors used data from these experiments to validate RPR simulations. Results of measurements of vertical and horizontal temperature differences within roofponds are discussed. Horizontal heat transfer within one water bag was effective. Thermal resistance at the outer surface of a water bag with a deflated glazing can be significant. Simulation shows that an RPR can provide comfort without supplemental sensible cooling during almost all hours of a typical summer in any U.S climate. Ceiling fans are important in most climates. In the most demanding climates, the residence and the pond insulating panels must have high R-value. A map is included that provides RPR design guidance. The simulations indicate that dehumidification will be required to control mold, mildew, and ceiling condensation in an RPR in most climates; energy and power displacement by an RPR is sensitive to the humidity control required and the efficiency of the dehumidifier used.

}, author = {Gene Clark and Fred M. Loxsom and Earl S. Doderer and Philip Haves} } @proceedings {351, title = {The Use of Dynamic Simulation Models to Evaluate Algorithms for Building Energy Control: Experience with HVACSIM+}, journal = {International Congress on Building Energy Management}, volume = {8}, year = {1987}, month = {09/1987}, address = {Lausanne, Switzerland}, author = {Arthur L. Dexter and Mahroo M. Eftekhari and Philip Haves and F{\'a}bio Gon{\c c}alves Jota} } @proceedings {353, title = {Development of SERI-RES within the UK Passive Solar Programme}, journal = {10th National Passive Solar Conference}, year = {1986}, month = {06/1986}, address = {Boulder, CO}, author = {John G.F. Littler and Philip Haves} } @proceedings {354, title = {Generation of Data for Passive Solar Building Simulation from a Three Dimensional Architectural Modelling System}, journal = {PLEA{\textquoteright}86 Conference}, year = {1986}, month = {09/1986}, address = {Pecs, Hungary}, author = {Cedric Green and Philip Haves} } @conference {55797, title = {The DOE-2 Computer Program for Thermal Simulation of Buildings}, booktitle = {American Institute of Physics (AIP)}, volume = {135}, number = {642}, year = {1985}, month = {01/1985}, publisher = {American Institute of Physics}, organization = {American Institute of Physics}, doi = {10.1063/1.35478}, author = {Birdsall, Bruce E. and Walter F. Buhl and Richard B. Curtis and Ender Erdem and Joseph Eto and James J. Hirsch and Karen H. Olson and Frederick C. Winkelmann} } @proceedings {355, title = {The Integration of Graphic and Thermal Simulation Models}, journal = {Computer Graphics {\textquoteright}85 Conference}, year = {1985}, month = {10/1985}, publisher = {Wembley, Online Publications Ltd}, address = {Pinner, Middlesex, UK}, author = {Cedric Green and Philip Haves and Paul Huddy} } @proceedings {55943, title = {New Features of the DOE-2.1c Energy Analysis Program}, journal = {International Building Performance Simulation Association}, year = {1985}, month = {01/1985}, publisher = {International Building Performance Simulation Association}, url = {http://www.ibpsa.org/proceedings/BS1985/BS85_195_200.pdf}, author = {Walter F. Buhl and Ender Erdem and Joseph H. Eto and James J. Hirsch and Frederick C. Winkelmann} } @conference {55945, title = {The DOE-2 Building Energy Analysis Program}, booktitle = {ASEAN Conference on Energy Conservation in Buildings}, year = {1984}, month = {05/1984}, address = {Singapore}, author = {Richard B. Curtis and Birdsall, Bruce E. and Walter F. Buhl and Ender Erdem and Joseph H. Eto and James J. Hirsch and Karen H. Olson and Frederick C. Winkelmann} } @proceedings {357, title = {Results of Validated Simulations of Roof Pond Residences}, journal = {8th National Passive Solar Conference}, year = {1983}, address = {Santa Fe, NM}, author = {Gene Clark and Fred M. Loxsom and Philip Haves and Earl S. Doderer} } @proceedings {358, title = {Selection and Sizing of Low Energy Cooling Systems for More Humid Climates}, journal = {2nd International Passive and Low Energy Architecture Conference}, year = {1983}, month = {06/1983}, address = {Crete, Greece}, author = {Philip Haves} } @proceedings {356, title = {SERI-RES: a Thermal Simulation Model for Passive Solar and Low Energy Buildings}, journal = {Design methods for Passive Solar Buildings Conf}, year = {1983}, month = {10/1983}, author = {Philip Haves} } @proceedings {360, title = {Accuracy of a Simple Method of Estimating the Minimum Temperature of a Sealed Roof Pond}, journal = {Annual Meeting of American Section of the International Solar Energy Society}, volume = {5}, year = {1982}, month = {07/1982}, pages = {709-714}, address = {Houston, TX}, abstract = {

Detailed heat flux and temperature measurements have been made in two residential scale roof pond buildings in San Antonio, Texas from July to November 1981. The minimum temprature of the 4 in deep roof pond sealed in PVC bags was approximately equal to the minimum ambient dry bulb temperature. The sensitivity of this equality to changes in meteorological conditions, maximum pond temperature and thermal load is evaluated using the measurements. Verified simulations are then used to evaluate the sensitivity of this equality to changes in the thermal load, and to changes in the depth, surface emittance and surface thermal resistance of the sealed pond in various climates. For the range of roof pond design options of interest in passive cooling of buildings, the minimum pond temperature was found to be within 2 F of the minimum ambient temperature in all climates considered. The equality of these minimum temperatures is advocated as a useful rule of thumb for feasibility assessment and as part of a simplified design methodology. The simulated minimum pond temperature was found to be surprisingly insensitive to a 50\% decrease in the fraction of pond area exposed to the sky.

}, author = {Brady Schutt and Gene Clark and Philip Haves and Merino, M.} } @proceedings {359, title = {Dehumidification and Passive Cooling for Retrofit and Conventional Construction}, journal = {7th National Passive Solar Conference}, year = {1982}, month = {07/1982}, address = {Knoxville, TN}, author = {Philip Haves and Fred M. Loxsom and Earl S. Doderer} } @proceedings {365, title = {Design and Operating Strategies and Sizing Relationships for Solar Regenerated Desiccant Dehumidifiers Used with Passive Cooling Systems}, journal = {1st International Passive \& Hybrid Cooling Conference}, year = {1981}, month = {11/1981}, address = {Miami, FL}, author = {Peter E. Nelson and Philip Haves} } @proceedings {366, title = {Economic Analysis of Desiccant Dehumidifiers in Passive Solar Residences}, journal = {1981 Annual Meeting of ASISE}, year = {1981}, month = {05/1981}, address = {Philadelphia, PA}, author = {Peter E. Nelson and McDougal, G. and Philip Haves} } @proceedings {363, title = {Experimental Validation of a Computer Model of a Solar Regenerated Desiccant Dehumidification System}, journal = {1st International Passive \& Hybrid Cooling Conference}, year = {1981}, month = {11/1981}, address = {Miami, FL}, author = {Peter E. Nelson and Philip Haves} } @conference {361, title = {Heat Loss Rates from Wetted Tilted Surfaces}, booktitle = {1st International Passive and Hybrid Cooling Conference, November 6-16, 1981}, series = {Passive Cooling}, year = {1981}, month = {11/1981}, publisher = {American Section of the International Solar Energy Society}, organization = {American Section of the International Solar Energy Society}, address = {Miami Beach, FL}, issn = {0895530333 9780895530332}, author = {Haines, R. and Philip Haves and Vollink, D.}, editor = {Arthur Bowen and Gene Clark} } @proceedings {362, title = {Measurement of Components of Heat Transfer in Passive Cooling Systems}, journal = {1st International Passive \& Hybrid Cooling Conference}, year = {1981}, month = {11/1981}, address = {Miami, FL}, author = {Fred M. Loxsom and Gene Clark and Merino, M. and Philip Haves} } @proceedings {364, title = {Simulated Performance of a Passively Cooled Residence with a Solar Regenerated Desiccant Dehumidifier}, journal = {1st International Passive \& Hybrid Cooling Conference}, year = {1981}, month = {11/1981}, address = {Miami, FL}, author = {Philip Haves} } @proceedings {367, title = {Heat Transfer in Passively Cooled Buildings}, journal = {ASME/AIChE National Heat Transfer Conference}, year = {1980}, month = {07/1980}, address = {Orlando, FL}, author = {Philip Haves and Bently, D. and Gene Clark} } @proceedings {368, title = {The Thermal Benefits and Cost Effectiveness of Earth Berming}, journal = {5th National Passive Solar Conference}, volume = {5.1}, year = {1980}, month = {10/1980}, address = {Amherst, MA}, abstract = {

A number of advantages are claimed for earth sheltered buildings; the earth provides both insulation and thermal storage and also serves to reduce infiltration and noise. This paper seeks to quantify the thermal advantages of both earth sheltering and perimeter insulation by comparing the simulated thermal performance of an earth sheltered house, a house with perimeter insulation and a house with neither. The fuel savings are then compared to the estimated construction costs to determine cost-effectiveness. The major saving from an earth sheltered building is obtained in colder climates where the effective elevation of the frost line due to the earth berms considerably reduces the cost of the foundation.

}, author = {Speltz, J. and Philip Haves} } @proceedings {369, title = {One Dimensional Representations of the Heat Flow Beneath a Building}, journal = {US DOE Solar Energy Storage Options Conference}, year = {1979}, month = {03/1979}, address = {San Antonio, TX}, author = {Philip Haves} } @article {370, title = {The Radio Structure of a Sample of 101 Quasars from the Parkes {\textpm}4{\textordmasculine} Survey}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {176}, year = {1976}, month = {08/1976}, pages = {275-306}, chapter = {275}, keywords = {Angular Distribution, Astronomical Catalogs, Quasars, Radio Emission, Radio Sources (Astronomy), Radio Spectra, Spectrum Analysis, Ultrahigh Frequencies}, author = {Michael Bentley and Philip Haves and Ralph E. Spencer and David Stannard} } @article {372, title = {High Resolution Observations of Extended Radio Sources at 1666 MHz}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {173}, year = {1975}, author = {Michael Bentley and Philip Haves and Ralph E. Spencer and David Stannard} } @article {371, title = {The Orientation of the Magnetic Field in Radio Sources}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {173}, year = {1975}, month = {11/1975}, pages = {53P-56P}, chapter = {53P}, abstract = {

Recent data on the polarization of extragalactic radio sources are used to investigate the distribution of Delta, the angle between the major axis of a source and the intrinsic position angle of the E vector of linear polarization. Previous work on this subject has led to widely divergent conclusions. It is found that sources of high radio luminosity usually have Delta near 90 deg, implying that the magnetic fields in such sources are oriented along the major axis. For radio galaxies with low luminosity, on the other hand, Delta tends to lie nearer zero deg.

}, keywords = {extragalactic radio sources, magnetic field configurations, polarization (waves), polarization characteristics, polarized electromagnetic radiation, radiant flux density, radio galaxies}, author = {Philip Haves and Robin G. Conway} } @article {373, title = {Polarization Parameters of 183 Extragalactic Radio Sources}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {173}, year = {1975}, author = {Philip Haves} } @article {375, title = {The Polarization of Radio Sources at 31 CM}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {169}, year = {1974}, month = {10/1974}, pages = {117-131}, chapter = {117}, abstract = {

Measurements of the linear polarization of extragalactic radio sources have been made over a range of wavelengths in order to study both the properties of the sources themselves and the Faraday rotation along the line of sight to the observer. As part of a continuing program of such measurements the flux densities and integrated polarizations of 226 sources (including 134 quasars) were observed at 966 MHz (lambda 31 cm), to complement previous measurements at lambda 49 and lambda 74 cm (Conway et al. 1972). These results have been combined with others at shorter wavelengths in a discussion of the polarization properties of quasars (Conway et al. 1974). All the sources have angular sizes of 1 arcmin or less

}, keywords = {Astronomical Catalogs, extragalactic radio sources, faraday effect, interferometry, microwave emission, polarized electromagnetic radiation, Quasars, radiant flux density, radio astronomy, statistical analysis, tables (data), very high frequencies}, author = {Philip Haves and Robin G. Conway and David Stannard} } @article {374, title = {QSOs of High Redshift?}, journal = {Nature}, volume = {252}, year = {1974}, month = {11/1974}, pages = {209-210}, chapter = {209}, author = {Ian W.A. Browne and Michael Bentley and Philip Haves and Neil J. McEwan and Ralph E. Spencer and David Stannard} } @article {376, title = {The Radio Polarization of Quasars}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {168}, year = {1974}, month = {07/1974}, pages = {137-162}, chapter = {137}, abstract = {

Observations over a wide range of wavelengths, 2.2 <= λ <= 73 cm, have been combined to define the wavelength variation of the degree of linear polarization m(λ) for 120 quasars with known redshift. For the majority, m(λ) decreases monotonically with increasing wavelength but for 35 sources the polarization curve is inverted at short wavelengths. A classification is given, based on both the polarization curve and the radio spectrum, and the results are interpreted in terms of the presence or absence of opaque components in the source. The depolarization which occurs at long wavelengths is accounted for by a combination of spectral effects and Faraday depolarization. For 46 steep-spectrum sources the depolarization curve appears to be dominated by the Faraday effect, and has been used to deduce the electron density within the radiating components. In this group of sources the correlation between depolarization and redshift noted by Kronberg et al. is confirmed and strengthened. A discussion is given of some theoretical models of radio sources in the light of the depolarization data.

}, author = {Robin G. Conway and Philip Haves and Philipp P. Kronberg and David Stannard and Jacques P. Vall{\'e}e and John F. C. Wardle} }