Building designers are increasingly relying on complex fenestration systems to reduce energy consumed for lighting and HVAC in low energy buildings. Radiance, a lighting simulation program, has been used to conduct daylighting simulations for complex fenestration systems. Depending on the configurations, the simulation can take hours or even days using a personal computer. This paper describes how to accelerate the matrix multiplication portion of a Radiance three-phase daylight simulation by conducting parallel computing on heterogeneous hardware of a personal computer. The algorithm was optimized and the computational part was implemented in parallel using OpenCL. The speed of new approach was evaluated using various daylighting simulation cases on a multicore central processing unit and a graphics processing unit. Based on the measurements and analysis of the time usage for the Radiance daylighting simulation, further speedups can be achieved by using fast I/O devices and storing the data in a binary format.

%B Journal of Building Performance Simulation %2 LBNL-6461E %R 10.1080/19401493.2013.795193 %0 Conference Proceedings %B 13th Conference of International Building Performance Simulation %D 2013 %T Functional Mock-Up Unit Import in EnergyPlus For Co-Simulation %A Thierry Stephane Nouidui %A Michael Wetter %A Wangda Zuo %XThis 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.

%B 13th Conference of International Building Performance Simulation %C Chambery, France %8 08/2013 %2 LBNL-6413E %0 Journal Article %J Engineering Applications of Computational Fluid Mechanics %D 2012 %T Reduction of numerical viscosity in FFD model %A Wangda Zuo %A Mingang Jin %A Qingyan Chen %B Engineering Applications of Computational Fluid Mechanics %V 6 %P 234-247 %G eng %N 2 %0 Conference Proceedings %B Proc. of the 9th International Modelica Conference %D 2012 %T Validation and Application of the Room Model of the Modelica Buildings Library %A Thierry Stephane Nouidui %A Phalak, Kaustubh %A Wangda Zuo %A Michael Wetter %XThe 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.

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.

%8 07/2012 %2 LBNL-5735E %0 Conference Proceedings %B the 2nd International Conference on Building Energy and Environment (COBEE2012) %D 2012 %T Validation of three dimensional fast fluid dynamics for indoor airflow simulations %A Mingang Jin %A Wangda Zuo %A Qingyan Chen %B the 2nd International Conference on Building Energy and Environment (COBEE2012) %C Boulder, CO %P 1055-1062 %G eng %0 Conference Paper %B 12th International Conference of the International Building Performance Simulation Association (Building Simulation 2011) %D 2011 %T Acceleration of Radiance for Lighting Simulation by using Parallel Computing with OpenCL %A Wangda Zuo %A Andrew McNeil %A Michael Wetter %A Eleanor S. Lee %XThis study attempted to accelerate annual daylighting simulations for fenestration systems in Radiance ray-tracing program. The algorithm was optimized to reduce both the redundant data input/output operations and floating-point operations. To further accelerate the simulation speed, calculation for matrices multiplications was implemented in parallel on a graphics processing unit using OpenCL, a cross-platform parallel programming language. Numerical experiments show that combination of above measures can speed up the annual daylighting simulations 101.7 times or 28.6 times when sky vector has 146 or 2306 elements, respectively.

%B 12th International Conference of the International Building Performance Simulation Association (Building Simulation 2011) %C Sydney, Australia %P p. 110-117 %8 11/2011 %G eng %1Windows and Daylighting Group

%2 LBNL-5049E %0 Conference Proceedings %B the 8th International Forum and Workshop on Combined Heat, Air, Moisture and Pollutant Simulations (CHAMPS 2011) %D 2011 %T Advanced simulations of building energy and control systems with an example of chilled water plant modeling %A Wangda Zuo %A Michael Wetter %B the 8th International Forum and Workshop on Combined Heat, Air, Moisture and Pollutant Simulations (CHAMPS 2011) %C Nanjing, China %G eng %0 Conference Proceedings %B 12th Conference of International Building Performance Ssimulation Association %D 2011 %T Modeling of Heat Transfer in Rooms in the Modelica "Buildings" Library %A Michael Wetter %A Wangda Zuo %A Thierry Stephane Nouidui %B 12th Conference of International Building Performance Ssimulation Association %S Proceedings of Building Simulation 2011 %C Sydney, Australia %P 1096-1103 %8 11/2011 %G eng %2 LBNL-5563E %0 Conference Proceedings %B the 8th International Modelica Conference %D 2011 %T Recent developments of the Modelica Buildings library for building energy and control systems %A Michael Wetter %A Wangda Zuo %A Thierry Stephane Nouidui %K building energy systems %K heating %XAt 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.

%B the 8th International Modelica Conference %C Dresden, Germany %G eng %U https://www.modelica.org/events/modelica2011/Proceedings/pages/papers/12_1_ID_113_a_fv.pdf %2 LBNL-4793E %0 Conference Proceedings %B 12th International Conference on Indoor Air Quality and Climate (Indoor Air 2011) %D 2011 %T Validation of a Fast-Fluid-Dynamics Model for Predicting Distribution of Particles with Low Stokes Number %A Wangda Zuo %A Qingyan Chen %K cfd %K ffd %K low stokes number %K particle transportation %X 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. %B 12th International Conference on Indoor Air Quality and Climate (Indoor Air 2011) %C Austin, Texas %8 06/2011 %G eng %0 Journal Article %J Building and Environment %D 2010 %T Fast and informative flow simulation in a building by using fast fluid dynamics model on graphics processing unit %A Wangda Zuo %A Qingyan Chen %B Building and Environment %V 45 %P 747-757 %G eng %N 3 %0 Conference Proceedings %B the 41st International HVAC&R congress %D 2010 %T Fast simulation of smoke transport in buildings %A Wangda Zuo %A Qingyan Chen %B the 41st International HVAC&R congress %C Beograd, Serbian %G eng %0 Conference Proceedings %B the 7th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2010) %D 2010 %T Impact of time-splitting schemes on the accuracy of FFD simulations %A Jianjun Hu %A Wangda Zuo %A Qingyan Chen %B the 7th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2010) %C Syracuse, NY %P 55-60 %G eng %0 Journal Article %J Numerical Heat Transfer, Part B Fundamentals %D 2010 %T Improvements on FFD modeling by using different numerical schemes %A Wangda Zuo %A Jianjun Hu %A Qingyan Chen %B Numerical Heat Transfer, Part B Fundamentals %V 58 %P 1-16 %G eng %N 1 %0 Conference Proceedings %B the 4th National Conference of IBPSA-USA (SimBuild2010) %D 2010 %T Improvements on the fast fluid dynamics model for indoor airflow simulation %A Wangda Zuo %A Qingyan Chen %B the 4th National Conference of IBPSA-USA (SimBuild2010) %C New York, NY %P 539-546 %G eng %0 Journal Article %J HVAC&R Research %D 2010 %T Simulations of air distribution in buildings by FFD on GPU %A Wangda Zuo %A Qingyan Chen %B HVAC&R Research %V 16 %P 783-796 %G eng %N 6 %0 Journal Article %J Flow, Turbulence and Combustion %D 2009 %T Anisotropy invariant Reynolds stress model of turbulence (AIRSM) and its application on attached and separated wall-bounded flows %A V. Kumar %A Bettina Frohnapfel %A Jovan JovanoviÄ‡ %A Michael Breuer %A Wangda Zuo %A Ibrahim HadziÄ‡ %A Richard Lechner %K Anisotrpoy %K Invariant map %K Reynolds stress model %K Reynolds-averaged Navier-Stokes %K Separated wall-bounded flow %K Turbulence %K Turbulence modeling %XNumerical 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.

%B Flow, Turbulence and Combustion %V 83 %P 81-103 %8 07/2009 %G eng %N 1 %& 81 %R 10.1007/s10494-008-9190-y %0 Conference Proceedings %B the 11th International Conference on Air Distribution in Rooms (RoomVent 2009) %D 2009 %T Fast parallelized flow simulations on graphic processing units %A Wangda Zuo %A Qingyan Chen %B the 11th International Conference on Air Distribution in Rooms (RoomVent 2009) %C Busan, Korea %G eng %0 Conference Proceedings %B 11th International IBPSA Conference (Building Simulation 2009) %D 2009 %T High performance computing for indoor air %A Wangda Zuo %A Qingyan Chen %B 11th International IBPSA Conference (Building Simulation 2009) %C Glasgow, U.K. %P 244-249 %G eng %0 Journal Article %J Indoor Air %D 2009 %T Real time or faster-than-real-time simulation of airflow in buildings %A Wangda Zuo %A Qingyan Chen %B Indoor Air %V 19 %P 33-44 %G eng %N 1 %0 Conference Proceedings %B the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) %D 2007 %T Computational fluid dynamics for indoor environment modeling: past, present, and future %A Qingyan Chen %A Zhao Zhang %A Wangda Zuo %B the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) %C Sendai, Japan %P 1-9 %G eng %6 3 %0 Conference Proceedings %B the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) %D 2007 %T Real time airflow simulation in buildings %A Wangda Zuo %A Qingyan Chen %B the 6th International Indoor Air Quality, Ventilation and Energy Conservation in Buildings Conference (IAQVEC 2007) %C Sendai, Japan %P 459-466 %G eng %6 2 %0 Conference Proceedings %B the 10th International IBPSA Conference (Building Simulation 2007) %D 2007 %T Validation of fast fluid dynamics for room airflow %A Wangda Zuo %A Qingyan Chen %B the 10th International IBPSA Conference (Building Simulation 2007) %C Beijing, China %P 980-983 %G eng %0 Journal Article %J Journal of Chongqing University (Natural Science Edition) %D 2004 %T Updating traditional CRM system by terminal server %A Wangda Zuo %A Tianyi Yang %A Wenyan Zou %B Journal of Chongqing University (Natural Science Edition) %V 27 %P 94-95 %G eng %N 1