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.

10adaylighting simulation10agraphics processing unit10amulticore central processing unit10aOpenCL10aparallel computing1 aZuo, Wangda1 aMcNeil, Andrew1 aWetter, Michael1 aLee, Eleanor, S. uhttps://windows.lbl.gov/publications/acceleration-matrix-multiplication-radiance-three-phase-daylighting-simulations01205nas a2200133 4500008003900000245006900039210006900108260001200177520072300189100003100912700002000943700001600963856009200979 2012 d00aValidation of the Window Model of the Modelica Buildings Library0 aValidation of the Window Model of the Modelica Buildings Library c07/20123 aThis 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.

1 aNouidui, Thierry, Stephane1 aWetter, Michael1 aZuo, Wangda uhttps://windows.lbl.gov/publications/validation-window-model-modelica-buildings-library01247nas a2200157 4500008004100000245009300041210006900134260003100203300001500234520064900249100001600898700001900914700002000933700002100953856011500974 2011 eng d00aAcceleration of Radiance for Lighting Simulation by using Parallel Computing with OpenCL0 aAcceleration of Radiance for Lighting Simulation by using Parall aSydney, Australiac11/2011 ap. 110-1173 aThis 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.

1 aZuo, Wangda1 aMcNeil, Andrew1 aWetter, Michael1 aLee, Eleanor, S. uhttps://windows.lbl.gov/publications/acceleration-radiance-lighting-simulation-using-parallel-computing-opencl