Accuracy Of HVAC Load Predictions: Validation Of EnergyPlus And DOE-2 Using An Instrumented Test Facility

Comparisons of predictions from EnergyPlus, DOE-2.1e, and DOE-2.2 with measurements from Lawrence Berkeley National Laboratory's FLEXLAB (R) test facility have been conducted with the aim of better understanding the accuracy of these engines. Differences between predicted performance versus actual performance as measured in FLEXLAB, at least for simple buildings, have been identified, starting with key test cases in ASHRAE Standard 140. The averages over the different tests of the magnitudes of the hour-by-hour differences are similar to 2.5% of the range and the daytime averages, which may be more important for both energy performance and occupant comfort, are similar to 5%. These results do not support the hypothesis that there is any significant difference in the ability of the three engines to predict thermal loads in spaces with conventional overhead air supply for mixing ventilation.