Application of the adaptive model proposed by ASHRAE 55 in the Brazilian climate context: raising some issues

This paper evaluates the adaptive method application proposed by the last version of ASHRAE 55 (2013) standard in two different climates in Brazil. ASHRAE 55 (2013) currently allows for linear and exponential methods to calculate the prevailing mean outdoor air temperature (Tpma(out)) and both are used to establish the acceptability zones. For the exponential method, two different α were used (0.6 and 0.8). Moreover, the Tpma(out) was calculated for two different time spans (7 and 30 days). Results indicate that choosing linear or exponential, and even a monthly method, to calculate the Tpma(out) is indifferent when small amplitudes are concerned; but it can lead to different limits of acceptability when significant day to day temperature variations are present. However, the impact on the sum of discomfort hours is minimal. In addition, the results of this paper indicates that it is possible to find significant percentages of thermal acceptability from previous field study below the lower limit of acceptability proposed by the ASHRAE 55 (2013) adaptive model. Thus, a clo adjustment zone is suggested.