@article {31495, title = {Efficient modeling of optically-complex, non-coplanar exterior shading: Validation of matrix algebraic methods}, journal = {Energy and Buildings}, volume = {174}, year = {2018}, month = {09/2018}, pages = {464 - 483}, abstract = {

It has long been established that shading windows with overhangs, fins, and other types of non-coplanar systems (NCS) is one of the most effective ways of controlling solar heat gains in buildings because they intercept solar radiation prior to entry into the building. Designers however often specify non-opaque materials (e.g., louvers, fritted glass, expanded metal mesh) for these systems in order to admit daylight, reduce lighting energy use, and improve indoor environmental quality. Most simulation tools rely on geometric calculations and radiosity methods to model the solar heat gain impacts of NCS and cannot model optically-complex materials or geometries. For daylighting analysis, optically-complex NCS can be modeled using matrix algebraic methods, although time-efficient parametric analysis has not yet been implemented. Determining the best design and/or material for static or operable NCS that minimize cooling, heating, and lighting energy use and peak demand requires an iterative process. This study describes and validates a matrix algebraic method that enables parametric energy analysis of NCS. Such capabilities would be useful not only for design but also for development of prescriptive energy-efficiency standards, rating and labeling systems for commercial products, development of design guidelines, and development of more optimal NCS technologies.

A facade or "F" matrix, which maps the transfer of flux from the NCS to the surface of the window, is introduced and its use is explained. A field study was conducted in a full-scale outdoor testbed to measure the daylight performance of an operable drop-arm awning. Simulated data were compared to measured data in order to validate the models. Results demonstrated model accuracy: simulated workplane illuminance was within 11-13\%, surface luminance was within 16-18\%, and the daylight glare probability was within 6-9\% of measured results. Methods used to achieve accurate results are discussed. Results of the validation of daylighting performance are applicable to solar heat gain performance. Since exterior shading can also significantly reduce peak demand, these models enable stakeholders to more accurately assess HVAC and lighting impacts in support of grid management and resiliency goals.

}, keywords = {bidirectional scattering distribution function (BSDF), daylighting, exterior shading, solar heat gains, validation; building energy simulation tools, windows.}, issn = {03787788}, doi = {10.1016/j.enbuild.2018.06.022}, url = {https://www.sciencedirect.com/science/article/pii/S0378778818302457?via\%3Dihub}, author = {Taoning Wang and Gregory Ward and Eleanor S. Lee} } @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 {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 {60342, title = {Equation-based languages {\textendash} A new paradigm for building energy modeling, simulation and optimization}, journal = {Energy and Buildings}, volume = {117}, year = {2015}, month = {04/2016}, pages = {290-300}, abstract = {

Most of the state-of-the-art building simulation programs implement models in imperative programming languages. This complicates modeling and excludes the use of certain efficient methods for simulation and optimization. In contrast, equation-based modeling languages declare relations among variables, thereby allowing the use of computer algebra to enable much simpler schematic modeling and to generate efficient code for simulation and optimization.

We contrast the two approaches in this paper. We explain how such manipulations support new use cases. In the first of two examples, we couple models of the electrical grid, multiple buildings, HVAC systems and controllers to test a controller that adjusts building room temperatures and PV inverter reactive power to maintain power quality. In the second example, we contrast the computing time for solving an optimal control problem for a room-level model predictive controller with and without symbolic manipulations. Exploiting the equation-based language led to 2200 times faster solution.

}, keywords = {Equation-based modeling, modelica, Multi-physics simulation, Optimal control, smart grid}, doi = {10.1016/j.enbuild.2015.10.017}, author = {Michael Wetter and Marco Bonvini and Thierry Stephane Nouidui} } @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} } @conference {2636, title = {Energy Monitoring Systems value, issues and recommendations based on five case studies}, booktitle = {Clima 2010 conference}, year = {2010}, address = {Antalya, Turkey}, author = {Paul Raferty and Marcus Keane and James O{\textquoteright}Donnell and Andrea Costa} } @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} } @conference {252, title = {Economizer Control Using Mixed Air Enthalpy}, booktitle = {the 7th International Conference of Enhanced Building Operations}, series = {7th}, year = {2007}, month = {2007}, address = {San Francisco, CA}, author = {Jingjuan Feng and Mingsheng Liu and Xiufeng Pang} } @conference {2655, title = {Energy Index Evaluation of Buildings in Function of the External Temperature}, booktitle = {Proc. Building Simulation 2007}, year = {2007}, month = {09/2007}, address = {Beijing, China}, author = {Papa, Renata Pietra and Patricia Romeiro da Silva Jota and Assis, Eleonora} } @article {3389, title = {Energy Performance of Underfloor Air Distribution Systems}, year = {2007}, institution = {California Energy Commission - Public Interest Energy Research Program}, author = {Fred S. Bauman and Thomas L. Webster and Hui Jin and Wolfgang Lukaschek and Corinne Benedek and Edward A. Arens and Paul F. Linden and Anna Lui and Walter F. Buhl and Darryl J. Dickerhoff} } @article {381, title = {Effect of Aggregation Kinetics on the Thermal Conductivity of Nanoscale Colloidal Solutions (Nanofluids)}, journal = {Nanoletters}, volume = {6}, year = {2006}, pages = {1529-1534}, chapter = {1529}, author = {Ravi S. Prasher and Prajesh Bhattacharya and Patrick E. Phelan} } @conference {382, title = {Effect of Coloidal Chemistry on the Thermal Conductivity of Nanofluids}, booktitle = {International Mechanical Engineering Congress \& Exposition}, year = {2006}, month = {11/2006}, address = {Chicago, IL}, author = {Ravi S. Prasher and Prajesh Bhattacharya and Patrick E. Phelan} } @proceedings {2803, title = {The Energy Performance of the Cold-Formed Steel-Frame and Wood-Frame Houses Developed for Thailand}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Prechaya Mahattanataw and Charunpat Puvanant and Darunee Mongkolsawat} } @article {383, title = {Enhanced Mass Transport in Nanofluids}, journal = {Nanoletters}, volume = {6}, year = {2006}, month = {03/2006}, pages = {419-423}, chapter = {419}, abstract = {

Thermal conductivity enhancement in nanofluids, which are liquids containing suspended nanoparticles, has been attributed to localized convection arising from the nanoparticles{\textquoteright} Brownian motion. Because convection and mass transfer are similar processes, the objective here is to visualize dye diffusion in nanofluids. It is observed that dye diffuses faster in nanofluids compared to that in water, with a peak enhancement at a nanoparticle volume fraction, φ, of 0.5\%. A possible change in the slope of thermal conductivity enhancement at that same φ signifies that convection becomes less important at higher φ. The enhanced mass transfer in nanofluids can be utilized to improve diffusion in microfluidic devices.

}, doi = {10.1021/nl0522532}, author = {S. Krishnamurthy and Prajesh Bhattacharya and Patrick E. Phelan and Ravi S. Prasher} } @proceedings {3394, title = {Evaluation of Demand Shifting Strategies With Thermal Mass in Large Commercial Buildings}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Peng Xu} } @proceedings {3393, title = {Evaluation of Methods for Determining Demand-Limiting Setpoint Trajectories in Commercial Buildings Using Short-Term Data Analysis}, journal = {SimBuild 2006}, year = {2006}, month = {08/2006}, address = {Cambridge, MA, USA}, author = {Kyoung-ho Lee and James E. Braun} } @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} } @conference {388, title = {Effect of Particle Material on the Static Thermal Conductivity of Nanofluids}, booktitle = {Heat Transfer Conference}, year = {2005}, month = {07/2005}, address = {San Francisco, CA}, author = {P. Vijayan and Prajesh Bhattacharya and S. Nara and W. Lai and Patrick E. Phelan and Ravi S. Prasher and David W. Song and J. Wang} } @article {277, title = {Effects of double glazed fa{\c c}ade on energy consumption, thermal comfort and condensation for a typical office building in Singapore}, journal = {Energy and Buildings}, volume = {37}, year = {2005}, month = {06/2005}, author = {Nyuk Hien Wong and Liping Wang and Aida Noplie Chandra and Anupama Rana Pandey and Xiaolin Wei} } @conference {385, title = {Experimental Determination of the Effect of Varying Base Fluid and Temperature on the Static Thermal Conductivity of Nanofluids}, booktitle = {ASME International Mechanical Engineering Congress and Exposition, November 5-11, 2005}, year = {2005}, month = {11/2005}, publisher = {ASME}, organization = {ASME}, address = {Orlando, FL}, abstract = {

The heat transfer abilities of fluids can be improved by adding small particles of sizes of the order of nanometers. Recently a lot of research has been done in evaluating the thermal conductivity of nanofluids using various nanoparticles. In our present work we address this issue by conducting a series of experiments to determine the effective thermal conductivity of alumina-nanofluids by varying the base fluid with water and antifreeze liquids like ethylene glycol and propylene glycol. Temperature oscillation method is used to find the thermal conductivity of the nanofluid. The results show the thermal conductivity enhancement of nanofluids depends on viscosity of the base fluid. Finally the results are validated with a recently proposed theoretical model.

}, isbn = {0-7918-4221-5}, doi = {10.1115/IMECE2005-81494}, author = {S. Nara and Prajesh Bhattacharya and P. Vijayan and W. Lai and W. Rosenthal and Patrick E. Phelan and Ravi S. Prasher and David W. Song and Jinlin Wang} } @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} } @conference {390, title = {Evaluation of the Temperature Oscillation Technique to Calculate Thermal Conductivity of Water and Systematic Measurement of the Thermal Conductivity of Aluminum Oxide {\textendash} Water Nanofluiids}, booktitle = {International Mechanical Engineering Congress \& Exposition,}, year = {2004}, month = {11/2004}, address = {Anaheim, CA}, author = {Prajesh Bhattacharya and P. Vijayan and Tang, T. and S. Nara and Patrick E. Phelan and Ravi S. Prasher and J. Wang and David W. Song} } @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} } @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} } @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} } @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 {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} }