ASHRAE 55 adaptive model application in hot and humid climates: the Brazilian case

ASHRAE Standard 55 is widely used to assess thermal comfort in buildings worldwide. The main purpose of this paper is to evaluate the adaptive method application proposed by ASHRAE 55 in two different climates in Brazil. This method relates the conditions for comfort to the “prevailing mean outdoor air temperature”. The currently available version of the Standard allows for linear and exponential methods to calculate the “prevailing mean”, and both are tested to establish the acceptability zones. The results indicate that choosing any of the methods to calculate the prevailing mean outdoor air temperature gives similar results when the temperature amplitudes are small; but it can lead to different limits of acceptability, and consequently sum of discomfort hours, when significant day-to-day temperature variations are present. In addition, the results indicate that it is possible to find significant percentages of thermal acceptability from previous studies below the lower limit of acceptability proposed by the Standard. As a result, a “clo adjustment zone” is suggested.