An empirical validation of window solar gain models and the associated interactions

An empirical validation of building energy simulation programs was performed in a test cell on the Swiss Federal Laboratories for Materials Testing and Research (EMPA) campus in Duebendorf, Switzerland. The purpose of this exercise was to evaluate the performances of three building energy simulation programs when simulating energy flows through a window (i.e. glazing unit and window frame). The programs used for this study were EnergyPlus, DOE-2.1E, and IDA-ICE. The inputs to the building energy simulation programs were ascertained through precise measurements and simulations, which are explained in detail in this paper. To assess overall performance, the cooling power measured in the experiment was compared with the programs' predictions. Thorough statistical analyses and comparisons were used to determine the impact of experiment output, input uncertainties and evaluate the programs. The absolute average difference between the experiment and predictions for EnergyPlus, DOE-2.1E, and IDA-ICE were 5.8, 9.9, and 6.0%, respectively.