Experimental study on human thermal response under temperature step change

The effects of neutral-hot (cold)-neutral temperature change on human thermal response are studied in 24 subjects by simulating 9 kinds of temperature step change conditions corresponding to different seasons in an artificial climate chamber, and the changes of physiological and subjective responses and whole body thermal load are obtained. It is found that the change of subjective response is ahead of the change of physiological response under different step change conditions. The physiological and psychological responses of the human body are asymmetrical before and after the step change. In the hot-neutral step change condition, the human body appears cold sensation overshooting. By analysing the change law of the various heat dissipation of the human body during the experiment, it is found that the reason for cold sensation overshooting is that the skin evaporative heat dissipation increases significantly, resulting in the total heat dissipation of the human body is much larger than the heat production. The thermal sensation in the dynamic environment of temperature step change has a linear relationship with the average skin temperature and its change rate, and a thermal sensation prediction model based on skin temperature is obtained. The thermal sensation prediction model based on thermal load is obtained by introducing human thermal load and its variation into the model. The comparison of PMV model, thermal sensation prediction model based on skin temperature and thermal sensation prediction model based on thermal load shows that the prediction model based on thermal load could better predict the human thermal sensation in the temperature step change environment.