Effect of thermal transient on human thermal comfort in temporarily occupied space in winter – A case study in Tianjin

Abstract

The acceptable temperature ranges of temporarily occupied space (TOS) such as supermarkets could be different from the ranges of normal indoor spaces such as offices. However, current thermal comfort standards do not distinguish such a space from normal spaces and identify its design temperature range clearly. This study proposed TOS, and explored human responses to TOS with the ultimate goal of finding its optimal design temperature range in winter. Questionnaire surveys were performed at six temperature levels in a climatic chamber in Tianjin. Human participants were exposed to outdoors for 20 min and then they stayed in the chamber for 40 min. During this period their thermal sensation, comfort and preference were recorded for evaluation at five different time points. The study shows that their neutral temperature ranges from 16.9 °C to 18.4 °C. Their thermal preference maintains “no change” in the range of 15.4 °C–19.3 °C. Meanwhile, from the viewpoint of thermal comfort, a temperature range of 15.4 °C–17.4 °C is highly desirable for occupants to stay in TOS. Considering the above three ranges, the optimal design temperature range for TOS in Tianjin is recommended to be 16.9 °C–17.4 °C, which achieves highly desirable thermal comfort, neutral thermal sensation and “no change” thermal preference simultaneously. This range is significantly lower than the design temperature range in Chinese national codes (20 °C–22 °C). The results of this study can be used as reference for future code formulation and building retrofitting.