Thermal responses and skin temperature to moderate temperature ramps in winter: An office-lab study

In order to explore the acceptable temperature limits of humans in temperature ramps by intermittent heating in the north China, the research was conducted in an office-lab. Four indoor dynamic heating environments with different initial temperatures (15-18 degrees C) and change rates (0.02-0.18 degrees C/min) were created. The room temperature gradually rose as people entered the room and divided into two phases by the ramping rates, which was fast in the first phase. During the filed experiments, the variations of overall and local thermal responses were investigated while environmental parameters was monitored. Additionally, the local skin temperatures of participants' hand and ankle were also recorded. The results indicated that the variations of skin temperature from different exposed parts were different. It indicated that humans can make active physiological adjustments according to environmental changes. Moreover, the subject's thermal responses were lagging and affected by the thermal experience. The thermal sensation vote (TSV) was statistically different between the two phases. The calf was the most significant factor on the overall thermal sensation. Furthermore, the TSV significantly affected other psychological responses. The relationships between the TSV and other thermal responses were observed. The thermal sensation evaluation models were established. In summary, the indoor temperature of 16-18 degrees C is recommended as the initial temperature when the temperature ramping rate is less than 0.2 degrees C/min. This study gives a theoretical guide for the creation of dynamic indoor thermal environments, which is beneficial for thermal comfort, health, and energy saving.