Evaluation Of EnergyGauge USA, A Residential Energy Design Software, Against Monitored Data

A new software, EnergyGauge USA®, is being developed for calculation of energy use in residential buildings. A simplified user interface allows buildings to be quickly defined and evaluated. Utilization of the DOE-2.1E energy simulation engine brings the computing power of hourly simulation to designers and raters. The software has enhancements to better simulate duct systems, air infiltration, attic and foundation thermal performance, heat pump part load characteristics and internal moisture capacitance. A recurring question with building energy software, regardless of the calculation rigor, is the relative accuracy of the estimates, particularly for cooling loads. To address this question, the software was used to estimate the hourly air conditioning electrical demand in three homes extensively monitored in Apopka, Florida. Each of the homes were unoccupied, and were identical in layout and orientation, yet contained different efficiency measures. A conventional concrete block home served as the project control house while a second had better insulated walls (autoclaved aerated concrete) and double-glazed windows. The third home, constructed with wood frame walls, had solar-control windows and an attic radiant barrier. Building geometry, construction and features were entered into the software with measured values being used for critical inputs. Monitored meteorological data was used to create weather files for the simulation and measured interior temperatures were input for each building. The resulting hourly simulation predictions for air conditioning power werethen compared to the monitored values for September 1998. Analysis showed excellent correspondence between the simulated and actual data. Average error was less than 4 percent for average hourly and less than 6 percent for peak hour air conditioning usage. Maximum errors were about 10 percent