Study on the local and overall thermal perceptions under nonuniform thermal exposure using a cooling chair

Abstract

The effect of back cooling, buttocks cooling, and a combined cooling at those two body parts simultaneously was studied in hot environments using a remodeled cooling chair. The results show that all the three local cooling methods can significantly improve the subjects’ overall (whole body) thermal comfort when the ambient temperature is 2 °C, 4 °C, and 6 °C higher than the neutral temperature of each subject. There is no significant difference between back cooling and buttocks cooling in improving overall thermal comfort, while the effect of combined cooling is better than the two separate cooling methods. During the controlled local cooling, an optimal balance is found between the thermal comfort profit from the decrease of the overall thermal sensation and the thermal comfort loss from the increase of the local cold feeling. The overall thermal sensation and the local thermal comfort of the body parts to which the local cooling is applied are the main factors determining the overall thermal comfort. Comparing to the local cooling methods used in this study, the subjects prefer to improve their thermal comfort by controlling the ambient temperature. The quantitative effect and related mechanism of local cooling provide by this study can help the development of such devices and strategies for application.