TY - Generic T1 - OPEN COMPUTING INFRASTRUCTURE FOR SHARING DATA ANALYTICS TO SUPPORT BUILDING ENERGY SIMULATIONS Y1 - 2019 A1 - Omer T. Karaguzel A1 - Mohammed Elshambakey A1 - Yimin Zhu A1 - Tianzhen Hong AB -

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'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.

ER - TY - JOUR T1 - Comparative Study of Air-Conditioning Energy Use of Four Office Buildings in China and USA JF - Energy and Buildings Y1 - 2018 A1 - Xin Zhou A1 - Da Yan A1 - Jingjing An A1 - Tianzhen Hong A1 - Xing Shi A1 - Xing Jin KW - Building envelope KW - climate KW - energy consumption KW - occupant behavior KW - office buildings KW - technological choice AB -

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.

VL - 169 ER - TY - JOUR T1 - Impact of post-rainfall evaporation from porous roof tiles on building cooling load in subtropical China JF - Applied Thermal Engineering Y1 - 2018 A1 - Lei Zhang A1 - Rongpeng Zhang A1 - Tianzhen Hong A1 - Yu Zhang A1 - Qinglin Meng KW - Building energy simulation KW - cooling load KW - energyplus KW - Evaporative Cooling KW - Rainfall event KW - Subtropical China AB -

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 °C and 3.2 °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.

VL - 142 UR - 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 JO - Applied Thermal Engineering ER - TY - JOUR T1 - A Novel Variable Refrigerant Flow (VRF) Heat Recovery System Model: Development and Validation JF - Energy and Buildings Y1 - 2018 A1 - Rongpeng Zhang A1 - Kaiyu Sun A1 - Tianzhen Hong A1 - Yoshinori Yura A1 - Ryohei Hinokuma KW - building performance simulation KW - controls KW - energy modeling KW - heat recovery KW - validation KW - Variable refrigerant flow AB -

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.

VL - 168 ER - TY - JOUR T1 - Occupancy prediction through Markov based feedback recurrent neural network (M-FRNN) algorithm with WiFi probe technology JF - Building and Environment Y1 - 2018 A1 - Wei Wang A1 - Jiayu Chen A1 - Tianzhen Hong A1 - Na Zhu AB -

Accurate occupancy prediction can improve facility control and energy efficiency of buildings. In recent years, buildings' 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's occupancy profile.

VL - 138 UR - 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 JO - Building and Environment ER - TY - JOUR T1 - Comparison of typical year and multiyear building simulations using a 55-year actual weather data set from China JF - Applied Energy Y1 - 2017 A1 - Ying Cui A1 - Da Yan A1 - Tianzhen Hong A1 - Chan Xiao A1 - Xuan Luo A1 - Qi Zhang KW - Actual weather data KW - building simulation KW - energy use KW - Multiyear simulation KW - Peak load   KW - Typical year AB -

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.

VL - 195 ER - TY - RPRT T1 - Modeling of HVAC Operational Faults in Building Performance Simulation Y1 - 2017 A1 - Rongpeng Zhang A1 - Tianzhen Hong KW - energy performance KW - energyplus KW - hvac system KW - Modeling and simulation KW - Operational fault KW - Thermal comfort   AB -

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—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.

ER - TY - RPRT T1 - Small and Medium Building Efficiency Toolkit and Community Demonstration Program Y1 - 2017 A1 - Mary Ann Piette A1 - Tianzhen Hong A1 - William J. Fisk A1 - Norman Bourassa A1 - Wanyu R. Chan A1 - Yixing Chen A1 - H.Y. Iris Cheung A1 - Toshifumi Hotchi A1 - Margarita Kloss A1 - Sang Hoon Lee A1 - Phillip N. Price A1 - Oren Schetrit A1 - Kaiyu Sun A1 - Sarah C. Taylor-Lange A1 - Rongpeng Zhang KW - CBES KW - commercial buildings KW - energy efficiency KW - energy modeling KW - energy savings KW - indoor air quality KW - indoor environmental quality KW - outdoor air measurement technology KW - outdoor airflow intake rate KW - retrofit KW - ventilation rate AB -

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’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.

U2 - LBNL-2001054 ER - TY - JOUR T1 - Spatial Distribution of Internal Heat Gains: A Probabilistic Representation and Evaluation of Its Influence on Cooling Equipment Sizing in Large Office Buildings JF - Energy and Buildings Y1 - 2017 A1 - Qi Zhang A1 - Da Yan A1 - Jingjing An A1 - Tianzhen Hong A1 - Wei Tian A1 - Kaiyu Sun KW - air handling unit KW - chiller plant KW - equipment sizing KW - internal heat gain KW - spatial distribution KW - spatial diversity KW - stochastic AB -

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.

ER - TY - JOUR T1 - A Thorough Assessment of China’s Standard for Energy Consumption of Buildings JF - Energy and Buildings Y1 - 2017 A1 - Da Yan A1 - Tianzhen Hong A1 - Cheng Li A1 - Qi Zhang A1 - Jingjing An A1 - shan Hu KW - China KW - code and standard KW - energy consumption KW - energy efficiency KW - Energy Use Intensity KW - outcome-based code AB -

China’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’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’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.

ER - TY - JOUR T1 - A Comparative Study on Energy Performance of Variable Refrigerant Flow Systems and Variable Air Volume Systems in Office Buildings JF - Applied Energy Y1 - 2016 A1 - Xinqiao Yu A1 - Da Yan A1 - Kaiyu Sun A1 - Tianzhen Hong A1 - Dandan Zhu KW - building simulation KW - comparative analysis KW - energy performance KW - field measurement KW - Variable Air Volume (VAV) Systems KW - Variable Refrigerant Flow (VRF) Systems AB -

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’ 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.    


 

 

ER - TY - JOUR T1 - The Impact of Evaporation Process on Thermal Performance of Roofs - Model Development and Numerical Analysis JF - Energy and Buildings Y1 - 2016 A1 - Lei Zhang A1 - Rongpeng Zhang A1 - Yu Zhang A1 - Tianzhen Hong A1 - Qinglin Meng A1 - Yanshan Feng KW - Evaporative Cooling KW - model development KW - Net zero energy building KW - Numerical analysis KW - Passive techniques KW - Porous building material KW - Roof thermal performance ER - TY - CONF T1 - Modeling and Simulation of Operational Faults of HVAC Systems Using Energyplus Y1 - 2016 A1 - Rongpeng Zhang A1 - Tianzhen Hong AB -

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.

U2 - LBNL-1004498 ER - TY - JOUR T1 - Commercial Building Energy Saver: An energy retrofit analysis toolkit JF - Applied Energy Y1 - 2015 A1 - Tianzhen Hong A1 - Mary Ann Piette A1 - Yixing Chen A1 - Sang Hoon Lee A1 - Sarah C. Taylor-Lange A1 - Rongpeng Zhang A1 - Kaiyu Sun A1 - Phillip N. Price KW - Building Technologies Department KW - Building Technology and Urban Systems Division KW - buildings KW - buildings energy efficiency KW - Commercial Building Systems KW - conservation measures KW - energy efficiency KW - energy use KW - energyplus KW - External KW - Retrofit Energy KW - simulation research AB -

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.

VL - 159 U2 - LBNL-1004502 ER - TY - JOUR T1 - Data Analysis and Stochastic Modeling of Lighting Energy Use in Large Office Buildings in China JF - Energy and Buildings Y1 - 2015 A1 - Xin Zhou A1 - Da Yan A1 - Tianzhen Hong A1 - Xiaoxin Ren KW - building simulation KW - energy use KW - Lighting modeling KW - occupant behavior KW - office buildings KW - Poisson distribution KW - stochastic modeling AB -

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.

VL - 86 U2 - LBNL-180389 ER - TY - JOUR T1 - Development and validation of a new variable refrigerant flow systemmodel in EnergyPlus JF - Energy and Buildings Y1 - 2015 A1 - Tianzhen Hong A1 - Kaiyu Sun A1 - Rongpeng Zhang A1 - Ryohei Hinokuma A1 - Shinichi Kasahara A1 - Yoshinori Yura KW - building simulation KW - energy modeling KW - energyplus KW - Heat pump KW - model validation KW - Variable refrigerant flow AB -

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.

VL - 117 U2 - LBNL-1004499 ER - TY - JOUR T1 - Modelica Buildings Library Y1 - 2015 A1 - Michael Wetter A1 - Wangda Zuo A1 - Thierry Stephane Nouidui A1 - Xiufeng Pang U2 - LBNL-1002944 ER - TY - JOUR T1 - Integrated Design for High Performance Buildings Y1 - 2014 A1 - Tianzhen Hong A1 - Cheng Li A1 - Richard C. Diamond A1 - Da Yan A1 - Qi Zhang A1 - Xin Zhou A1 - Siyue Guo A1 - Kaiyu Sun A1 - Jingyi Wang U2 - LBNL-6991E ER - TY - JOUR T1 - Building energy modeling programs comparison Research on HVAC systems simulation part Y1 - 2013 A1 - Xin Zhou A1 - Da Yan A1 - Tianzhen Hong A1 - Dandan Zhu KW - Building energy modeling programs KW - comparison tests KW - HVAC system simulation KW - theory analysis AB -

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.

ER - TY - RPRT T1 - Comparison of Building Energy Modeling Programs: HVAC Systems Y1 - 2013 A1 - Xin Zhou A1 - Tianzhen Hong A1 - Da Yan U2 - LBNL-6432E ER - TY - RPRT T1 - Data Analysis and Modeling of Lighting Energy Use in Large Office Buildings Y1 - 2013 A1 - Xin Zhou A1 - Da Yan A1 - Xiaoxin Ren A1 - Tianzhen Hong KW - building simulation KW - energy use KW - lighting KW - modeling KW - occupant behavior KW - office buildings KW - Poisson distribution AB -

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.

ER - TY - JOUR T1 - A Detailed Loads Comparison of Three Building Energy Modeling Programs: EnergyPlus, DeST and DOE-2.1E JF - Building Simulation Y1 - 2013 A1 - Dandan Zhu A1 - Tianzhen Hong A1 - Da Yan A1 - Chuang Wang KW - building energy modeling program KW - building thermal loads KW - comparison KW - dest KW - DOE-2.1E KW - energyplus AB -

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.

PB - Tsinghua University Press VL - 6 IS - 3 ER - TY - Generic T1 - Functional Mock-Up Unit Import in EnergyPlus For Co-Simulation T2 - 13th Conference of International Building Performance Simulation Y1 - 2013 A1 - Thierry Stephane Nouidui A1 - Michael Wetter A1 - Wangda Zuo AB -

This paper describes how to use the recently implemented Functional Mock-up Unit (FMU) for co-simulation import interface in EnergyPlus to link EnergyPlus with simulation tools packaged as FMUs. The interface complies with the Functional Mock-up Interface (FMI) for co-simulation standard version 1.0, which is an open standard designed to enable links between different simulation tools that are packaged as FMUs. This article starts with an introduction of the FMI and FMU concepts. We then discuss the implementation of the FMU import interface in EnergyPlus. After that, we present two use cases. The first use case is to model a HVAC system in Modelica, export it as an FMU, and link it to a room model in EnergyPlus. The second use case is an extension of the first case where a shading controller is modeled in Modelica, exported as an FMU, and used in the EnergyPlus room model to control the shading device of one of its windows. In both cases, the FMUs are imported into EnergyPlus which models the building envelope and manages the data-exchange between the envelope and the systems in the FMUs during run-time.

JF - 13th Conference of International Building Performance Simulation CY - Chambery, France U2 - LBNL-6413E ER - TY - CONF T1 - Application of a stochastic window use model in EnergyPlus T2 - SimBuild 2012, 5th National Conference of IBPSA-USA, August 1-3, 2012 Y1 - 2012 A1 - Spencer M. Dutton A1 - Hui Zhang A1 - Yongchao Zhai A1 - Edward A. Arens A1 - Youness Bennani Smires A1 - Samuel L. Brunswick A1 - Kyle S. Konis A1 - Philip Haves AB -

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.

JF - SimBuild 2012, 5th National Conference of IBPSA-USA, August 1-3, 2012 CY - Madison, WI UR - https://escholarship.org/uc/item/2gm7r783 ER - TY - CONF T1 - Comparative research in building energy modeling programs T2 - China Annual HVACR Conference Y1 - 2012 A1 - Dandan Zhu A1 - Tianzhen Hong A1 - Da Yan A1 - Chuang Wang KW - advanced building software: energyplus KW - building energy modeling program KW - building simulation KW - comparison KW - dest KW - doe-2 KW - energyplus KW - simulation research group KW - test JF - China Annual HVACR Conference CY - China (in Chinese) ER - TY - RPRT T1 - Comparison of Building Energy Modeling Programs: Building Loads Y1 - 2012 A1 - Dandan Zhu A1 - Tianzhen Hong A1 - Chuang Wang U2 - LBNL-6034E ER - TY - JOUR T1 - Reduction of numerical viscosity in FFD model JF - Engineering Applications of Computational Fluid Mechanics Y1 - 2012 A1 - Wangda Zuo A1 - Mingang Jin A1 - Qingyan Chen VL - 6 IS - 2 ER - TY - CONF T1 - A Retrofit Tool for Improving Energy Efficiency of Commercial Buildings T2 - ACEEE 2012 Summer Study Y1 - 2012 A1 - Mark D. Levine A1 - Wei Feng A1 - Jing Ke A1 - Tianzhen Hong A1 - Nan Zhou KW - building simulation KW - buildings KW - China KW - commercial building KW - energy efficiency measures KW - retrofit tool KW - simulation research group AB -

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. 

JF - ACEEE 2012 Summer Study CY - Asilomar, CA UR - http://aceee.org/files/proceedings/2012/data/papers/0193-000098.pdf#page=1 U2 - LBNL-6553E ER - TY - Generic T1 - Validation and Application of the Room Model of the Modelica Buildings Library T2 - Proc. of the 9th International Modelica Conference Y1 - 2012 A1 - Thierry Stephane Nouidui A1 - Phalak, Kaustubh A1 - Wangda Zuo A1 - Michael Wetter AB -

The Modelica Buildings library contains a package with a model for a thermal zone that computes heat transfer through the building envelope and within a room. It considers various heat transfer phenomena of a room, including conduction, convection, short-wave and long-wave radiation. The first part of this paper describes the physical phenomena considered in the room model. The second part validates the room model by using a standard test suite provided by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). The third part focuses on an application where the room model is used for simulation-based controls of a window shading device to reduce building energy consumption.

JF - Proc. of the 9th International Modelica Conference CY - Munich, Germany U2 - LBNL-5932E ER - TY - RPRT T1 - Validation of the Window Model of the Modelica Buildings Library Y1 - 2012 A1 - Thierry Stephane Nouidui A1 - Michael Wetter A1 - Wangda Zuo AB -

This paper describes the validation of the window model of the free open-source Modelica Buildings library. This paper starts by describing the physical modeling assumptions of the window model. The window model can be used to calculate the thermal and angular properties of glazing systems. It can also be used for steady-state simulation of heat transfer mechanism in glazing systems. We present simulation results obtained by comparing the window model with WINDOW 6 the well established simulation tool for steady-state heat transfer in glazing systems. We also present results obtained by comparing the window model with measurements carried out in a test cell at the Lawrence Berkeley National Laboratory.

U2 - LBNL-5735E ER - TY - Generic T1 - Validation of three dimensional fast fluid dynamics for indoor airflow simulations T2 - the 2nd International Conference on Building Energy and Environment (COBEE2012) Y1 - 2012 A1 - Mingang Jin A1 - Wangda Zuo A1 - Qingyan Chen JF - the 2nd International Conference on Building Energy and Environment (COBEE2012) CY - Boulder, CO ER - TY - Generic T1 - Advanced simulations of building energy and control systems with an example of chilled water plant modeling T2 - the 8th International Forum and Workshop on Combined Heat, Air, Moisture and Pollutant Simulations (CHAMPS 2011) Y1 - 2011 A1 - Wangda Zuo A1 - Michael Wetter JF - the 8th International Forum and Workshop on Combined Heat, Air, Moisture and Pollutant Simulations (CHAMPS 2011) CY - Nanjing, China ER - TY - CONF T1 - A Comparison of DeST and EnergyPlus T2 - China HVAC Simulation Conference Y1 - 2011 A1 - Dandan Zhu A1 - Chuang Wang A1 - Da Yan A1 - Tianzhen Hong KW - building simulation KW - comparison KW - dest KW - energy modeling KW - energyplus KW - simulation research KW - simulation research group KW - test cases JF - China HVAC Simulation Conference CY - Beijing ER - TY - Generic T1 - Modeling of Heat Transfer in Rooms in the Modelica "Buildings" Library T2 - 12th Conference of International Building Performance Ssimulation Association Y1 - 2011 A1 - Michael Wetter A1 - Wangda Zuo A1 - Thierry Stephane Nouidui JF - 12th Conference of International Building Performance Ssimulation Association T3 - Proceedings of Building Simulation 2011 CY - Sydney, Australia U2 - LBNL-5563E ER - TY - Generic T1 - Recent developments of the Modelica Buildings library for building energy and control systems T2 - the 8th International Modelica Conference Y1 - 2011 A1 - Michael Wetter A1 - Wangda Zuo A1 - Thierry Stephane Nouidui KW - building energy systems KW - heating AB -

At the Modelica 2009 conference, we introduced the Buildings library, a freely available Modelica library for building energy and control systems [16]. This paper reports the updates of the library and presents example applications for a range of heating, ventilation and air conditioning (HVAC) systems. Over the past two years, the library has been further developed. The number of HVAC components models has been doubled and various components have been revised to increase numerical robustness. The paper starts with an overview of the library architecture and a description of the main packages. To demonstrate the features of the Buildings library, applications that include multizone airow simulation as well as supervisory and local loop control of a variable air volume (VAV) system are briey described. The paper closes with a discussion of the current development.

JF - the 8th International Modelica Conference CY - Dresden, Germany UR - https://www.modelica.org/events/modelica2011/Proceedings/pages/papers/12_1_ID_113_a_fv.pdf U2 - LBNL-4793E ER - TY - Generic T1 - Validation of a Fast-Fluid-Dynamics Model for Predicting Distribution of Particles with Low Stokes Number T2 - 12th International Conference on Indoor Air Quality and Climate (Indoor Air 2011) Y1 - 2011 A1 - Wangda Zuo A1 - Qingyan Chen KW - cfd KW - ffd KW - low stokes number KW - particle transportation AB - To design a healthy indoor environment, it is important to study airborne particle distribution indoors. As an intermediate model between multizone models and computational fluid dynamics (CFD), a fast fluid dynamics (FFD) model can be used to provide temporal and spatial information of particle dispersion in real time. This study evaluated the accuracy of the FFD for predicting transportation of particles with low Stokes number in a duct and in a room with mixed convection. The evaluation was to compare the numerical results calculated by the FFD with the corresponding experimental data and the results obtained by the CFD. The comparison showed that the FFD could capture major pattern of particle dispersion, which is missed in models with well-mixed assumptions. Although the FFD was less accurate than the CFD partially due to its simplification in numeric schemes, it was 53 times faster than the CFD. JF - 12th International Conference on Indoor Air Quality and Climate (Indoor Air 2011) CY - Austin, Texas ER - TY - JOUR T1 - Fast and informative flow simulation in a building by using fast fluid dynamics model on graphics processing unit JF - Building and Environment Y1 - 2010 A1 - Wangda Zuo A1 - Qingyan Chen VL - 45 IS - 3 ER - TY - Generic T1 - Fast simulation of smoke transport in buildings T2 - the 41st International HVAC&R congress Y1 - 2010 A1 - Wangda Zuo A1 - Qingyan Chen JF - the 41st International HVAC&R congress CY - Beograd, Serbian ER - TY - Generic T1 - Impact of time-splitting schemes on the accuracy of FFD simulations T2 - the 7th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2010) Y1 - 2010 A1 - Jianjun Hu A1 - Wangda Zuo A1 - Qingyan Chen JF - the 7th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2010) CY - Syracuse, NY ER - TY - JOUR T1 - Impacts of Static Pressure Reset on VAV System Air Leakage, Fan Power, and Thermal Energy JF - ASHRAE Transactions Y1 - 2010 A1 - Mingsheng Liu A1 - Jingjuan Feng A1 - Zhan Wang A1 - Keke Zheng A1 - Xiufeng Pang VL - 116 IS - 1 ER - TY - JOUR T1 - Improvements on FFD modeling by using different numerical schemes JF - Numerical Heat Transfer, Part B Fundamentals Y1 - 2010 A1 - Wangda Zuo A1 - Jianjun Hu A1 - Qingyan Chen VL - 58 IS - 1 ER - TY - Generic T1 - Improvements on the fast fluid dynamics model for indoor airflow simulation T2 - the 4th National Conference of IBPSA-USA (SimBuild2010) Y1 - 2010 A1 - Wangda Zuo A1 - Qingyan Chen JF - the 4th National Conference of IBPSA-USA (SimBuild2010) CY - New York, NY ER - TY - JOUR T1 - Simulations of air distribution in buildings by FFD on GPU JF - HVAC&R Research Y1 - 2010 A1 - Wangda Zuo A1 - Qingyan Chen VL - 16 IS - 6 ER - TY - JOUR T1 - Anisotropy invariant Reynolds stress model of turbulence (AIRSM) and its application on attached and separated wall-bounded flows JF - Flow, Turbulence and Combustion Y1 - 2009 A1 - V. Kumar A1 - Bettina Frohnapfel A1 - Jovan Jovanović A1 - Michael Breuer A1 - Wangda Zuo A1 - Ibrahim Hadzić A1 - Richard Lechner KW - Anisotrpoy KW - Invariant map KW - Reynolds stress model KW - Reynolds-averaged Navier-Stokes KW - Separated wall-bounded flow KW - Turbulence KW - Turbulence modeling AB -

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.

VL - 83 IS - 1 ER - TY - Generic T1 - Fast parallelized flow simulations on graphic processing units T2 - the 11th International Conference on Air Distribution in Rooms (RoomVent 2009) Y1 - 2009 A1 - Wangda Zuo A1 - Qingyan Chen JF - the 11th International Conference on Air Distribution in Rooms (RoomVent 2009) CY - Busan, Korea ER - TY - Generic T1 - High performance computing for indoor air T2 - 11th International IBPSA Conference (Building Simulation 2009) Y1 - 2009 A1 - Wangda Zuo A1 - Qingyan Chen JF - 11th International IBPSA Conference (Building Simulation 2009) CY - Glasgow, U.K. ER - TY - JOUR T1 - Real time or faster-than-real-time simulation of airflow in buildings JF - Indoor Air Y1 - 2009 A1 - Wangda Zuo A1 - Qingyan Chen VL - 19 IS - 1 ER - TY - Generic T1 - Computational fluid dynamics for indoor environment modeling: past, present, and future T2 - the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) Y1 - 2007 A1 - Qingyan Chen A1 - Zhao Zhang A1 - Wangda Zuo JF - the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) CY - Sendai, Japan ER - TY - CONF T1 - Computer Model of a University Building Using the EnergyPlus Program T2 - Proc. Building Simulation 2007 Y1 - 2007 A1 - Danielle Monfet A1 - Radu Zmeureanu A1 - Roland Charneux A1 - Nicolas Lemire JF - Proc. Building Simulation 2007 CY - Beijing, China ER - TY - CONF T1 - Coverage Problem for Sensors Embedded in Temperature Sensitive Environments T2 - IEEE Infocom, 2007 Y1 - 2007 A1 - Arunabha Sen A1 - Nibedita Das A1 - Ling Zhou A1 - Bao Hong Shen A1 - Sudheendra Murthy A1 - Prajesh Bhattacharya JF - IEEE Infocom, 2007 CY - Anchorage, AL ER - TY - Generic T1 - Real time airflow simulation in buildings T2 - the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) Y1 - 2007 A1 - Wangda Zuo A1 - Qingyan Chen JF - the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) CY - Sendai, Japan ER - TY - CONF T1 - The Study of a Simple HVAC Interface of EnergyPlus in the Chinese Language T2 - Proc. Building Simulation 2007 Y1 - 2007 A1 - Junjie Liu A1 - Wenshen Li A1 - Xiaojie Zhou JF - Proc. Building Simulation 2007 CY - Beijing, China ER - TY - Generic T1 - Validation of fast fluid dynamics for room airflow T2 - the 10th International IBPSA Conference (Building Simulation 2007) Y1 - 2007 A1 - Wangda Zuo A1 - Qingyan Chen JF - the 10th International IBPSA Conference (Building Simulation 2007) CY - Beijing, China ER - TY - CONF T1 - Case Study of Continuous Commissioning in an Office Building T2 - the 6th International Conference of Enhanced Building Operations Y1 - 2006 A1 - Xiufeng Pang A1 - Zheng, B A1 - Mingsheng Liu JF - the 6th International Conference of Enhanced Building Operations CY - Shenzhen, China ER - TY - CONF T1 - Building Pressure Control in VAV System with Relief Air Fan T2 - the 5th International Conference of Enhanced Building Operations Y1 - 2005 A1 - Xiufeng Pang A1 - Zheng, B A1 - Mingsheng Liu JF - the 5th International Conference of Enhanced Building Operations CY - Pittsburgh, PA ER - TY - CONF T1 - Continuous Commissioning of an Office Building T2 - the 5th International Conference of Enhanced Building Operations Y1 - 2005 A1 - Zheng, B A1 - Mingsheng Liu A1 - Xiufeng Pang JF - the 5th International Conference of Enhanced Building Operations CY - Pittsburgh, PA ER - TY - CONF T1 - Using a Fan Air Flow Station to Control Building Static Pressure in a VAV System T2 - the 2005 International Solar Energy Conference Y1 - 2005 A1 - Zheng, B A1 - Xiufeng Pang A1 - Mingsheng Liu JF - the 2005 International Solar Energy Conference CY - Orlando, FL ER - TY - JOUR T1 - Heat transfer and natural ventilation from single-sided heated solar chimney for buildings JF - Journal of Asian Architecture and Building Engineering Y1 - 2004 A1 - Angui Li A1 - Phillip Jones A1 - Pingge Zhao A1 - Liping Wang VL - 3 IS - 2 ER - TY - JOUR T1 - Updating traditional CRM system by terminal server JF - Journal of Chongqing University (Natural Science Edition) Y1 - 2004 A1 - Wangda Zuo A1 - Tianyi Yang A1 - Wenyan Zou VL - 27 IS - 1 ER - TY - JOUR T1 - On Approaches to Couple Energy Simulation and Computational Fluid Dynamics Programs JF - Building and Environment Y1 - 2002 A1 - Zhiqiang Zhai A1 - Qingyan Chen A1 - Philip Haves A1 - Joseph H. Klems AB -

Energy simulation (ES) and computational fluid dynamics (CFD) can play important roles in building design by providing complementary information about the buildings' 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.

VL - 37 ER - TY - CONF T1 - Strategies for Coupling Energy Simulation Programs and Computational Fluid Dynamics Programs T2 - Building Sim 2001 Y1 - 2001 A1 - Zhiqiang Zhai A1 - Qingyan Chen A1 - Joseph H. Klems A1 - Philip Haves AB -

Energy simulation (ES) and computational fluid dynamics (CFD) can play important roles in building design by providing complementary information about the buildings' 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.

JF - Building Sim 2001 CY - Rio de Janeiro, Brazil VL - 1 U1 -

Simulation Research Group

U2 - LBNL-48286 ER -