A thermal comfort model for the non-uniform thermal environments

Abstract

This study aims to build models to predict the overall thermal comfort in the non-uniform thermal environments. Nine non-uniform thermal conditions with the locally supplied airflows were created with 24 healthy subjects recruited. Subjects’ thermal sensation as well as thermal comfort on the whole body and the body parts were surveyed. The overall percentage of dissatisfied (PD) was higher than the predicted percentage of dissatisfied (PPD) by the PMV-PPD model when the thermal non-uniformity exceeded a certain level. The deviation between PD and PPD increased along with the local percentage of dissatisfied, which rised with the thermal non-uniformity level. The overall percentages of dissatisfied depended on the local percentage of dissatisfied as well as the overall thermal sensation vote. A PD model was therefore proposed by considering both the overall thermal sensation vote and the local percentage of dissatisfied on the mainly exposed body part. As well, another PD model was developed by averaging the max. and the min. local percentage of dissatisfied. The PD models were verified to be credible, they are capable of predicting the occupants’ percentage of dissatisfied in the non-uniform thermal environment by combining the previous thermal regulation model and the thermal sensation model.