Calculation of the predicted comfort level of occupants of buildings served by modern HVAC systems is a complicated process, requiring analysis of up to seven variables. Equations and tables are provided in Chapter 8 of the ASHRAE Handbook of Fundamentals (ASHRAE 1989) but it is both difficult and impractical for the average mechanical engineer to use this information to make accurate comparisons of design conditions. The analysis, however, can be more easily accomplished with the aid of modern personal computers, given the proper model. Different models have been used over the past several years and all require the input of the seven basic variables. In the preparation of the revision to ASHRAE Standard 55-1981 (ASHRAE 1981), members of SPC 55-1981R evaluated several available models. In order to provide the HVAC engineer with a tool to better understand the response of individuals to the environment, a computer model developed from that evaluation is presented.

KEYWORDS: thermal comfort, microcomputers, calculating, occupiers, buildings, building services, computer programs, models.