Annual Heating and Cooling Requirements and Design-Day Performance for a Residential Model in Six Climates: A Comparison of NBSLD, BLAST 2, and DOE-2.1

摘要

A comparison was made of heating- and cooling-load predictions made by three public-domain-building energy-analysis computer programs: NBSLD, BLAST 2, and DOE-2.1. DOE-2.1 analyses were made using both ASHRAE standard weighting factors (SWF's), and custom weighting factors (CWF's) calculated by the program for the specific thermal model. The thermal model used for the comparison is based on a typical, current-practice single-family detached residence. Three different kinds of comparisons were made: (1) Monthly and annual load calculations were compared for six locations spanning the range of climates in the continental US. (2) Predicted changes in annual heating and cooling loads (BLAST 2 and DOE-2.1 (CWF) only) from a baseline case were compared for a single climate (Washington, DC). (3) Hourly heating- and cooling-load predictions were compared for design days that are representative of summer, winter, and transitional-season weather conditions for a temperate climate. Annual heating-load predictions show generally good agreement for all climates and consistent predicted changes from one climate to another, with the exception of the DOE-2.1 (SWF) predictions, which show marked underestimates for mild heating climates. Both DOE-2.1 (SWF) and (CWF) annual cooling-load predictions are significantly higher (25% to 35%) than the (almost alike) BLAST 2 and NBSLD predictions for all climates but one (the exception is believed to be coincidental). The quality of agreement between the BLAST 2 and DOE-2.1 (CWF) predictions for the load changes from the respective baselines was quite good for essentially all of the input variations examined. Design-day analyses for three typical days show acceptable agreement, with the greatest differences occurring in the predicted loads for the transitional-season design day, when heating and cooling loads are smallest. (ERA citation 05:033779)