Analysis on body heat losses and its effect on thermal sensation of people under moderate activities

The motivation of this study is to explore the changes of heat losses of people who undertake moderate activities and its effect on thermal sensation. Based on heat transfer equations and experimental data, heat losses have been calculated. The results have shown that in all conditions, the total ratio of latent heat loss (LHL) and sensible heat loss (SHL) is almost constant ranging from 0.9 to 0.95. With increase of LHL or decrease of SHL, people's mean thermal sensation vote (TSV) will increase regardless of whether they are in thermal balance. Skin wettedness is also related to TSV. Further study has discovered that ratios of LHL (RLHL) and SHL (RSHL) are correlated to TSV separately. By polynomial regression, two predicting equations have been fitted based on RSHL and RLHL, and they are essentially coincident with the sum of RSHL and RLHL being 0.93. The validity of predicting equations has been verified by using independent experimental data. Either of the equations can be used to predict TSV under moderate activities. Different from the current heat balance theory in thermal comfort, attention has been put on the change of ratios of heat losses in this paper, which provides a new perspective to understand thermal comfort under higher level of activities.