Thermal comfort prediction considering thermal adaptation based on facial temperature using thermal images and subjective indexes

Abstract

The aim of this study is to predict thermal comfort based on a subjective evaluation index of occupants and thermal imaging data, which are physiological signals, while considering thermal adaptation. This study was conducted in an office in the winter, and three subjective evaluation indexes were used. Air temperature data was obtained using a specific equipment, and the facial temperature was recorded using a thermal imaging camera. Based on analysis, thermal adaptation yielded different results at the same facial temperature. In previous studies, a facial temperature of 33 °C before thermal adaptation signified discomfort. However, the same facial temperature of 33 °C after thermal adaptation signified comfort. This implies that simple indexes and physiological signals based on thermal imaging are insufficient to predict the subjective thermal sensation of occupants. Therefore, accuracy of thermal comfort prediction can be improved significantly by considering thermal adaptation using the existing subjective evaluation indexes as well as by considering the results of studies pertaining to facial temperature.