Adaptation of the BESTEST intermodel comparison method for proposed ASHRAE Standard 140P: Method of test for building energy simulation programs

An ASHRAE Standard Method of Test is being developed for systematically testing whole-building energy simulation models and diagnosing the sources of predictive disagreement. The procedure, ASHRAE Proposed Standard 140P, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs, uses the comparative testing approach. In this method, a set of test cases is carefully defined so that equivalent input files can be developed for a variety of detailed and simplified whole building energy simulation programs. Results are then generated and compared using a variety of detailed simulation programs and/or different versions of one simulation program. In the proposed ASHRAE Standard 140P, the tests progress systematically from extremely simple to relatively realistic. The more realistic cases, while geometrically simple, test the ability of the programs to model such combined effects as thermal mass, direct solar gain windows, window shading devices, internally generated heat, infiltration, sunspaces, and dead-band and set-back thermostat control. The more simplified cases facilitate diagnosis by allowing excitation of particular heat transfer mechanisms. Output values for the cases, such as annual loads, annual maximum and minimum temperatures, peak loads, and some hourly data, are compared and used in conjunction with diagnostic logic to determine the algorithmsmore » responsible for prediction differences.« less