A novel method of calculating mean skin temperature with high thermal sensitivity for thermal sensation evaluation

Mean skin temperature of the body is an important physiological parameter reflecting human thermal sensation and state of heat exchange between human body and its surrounding thermal environment. There is limited research on the mean skin temperature distinguishing the cool and warm sensation, even though the sensitivity of local body parts to cold and warm is not identical. Therefore, a novel method of calculating mean skin temperatures (t_nsk) with the weighted mean of the influential body parts was established to reflect personal thermal sensation in moderate cool and warm environments. An experimental study was conducted in a climate chamber where sedentary occupants were exposed to the temperatures between 18 °C to 28 °C with different clothing ensembles to maintain thermal statuses of being between “slightly cool” to “slightly warm”. Thermal sensations and local skin temperatures of occupants were compared between neutral and non-neutral conditions to determine the influential body sites for t_nsk. It was found that in slightly cool conditions with the winter clothing of 1.0 clo, t_nsk could be explained by the weighted mean of instep (coefficient of 0.28), back lower leg (0.23), front thigh (0.18), low arm (0.16) and upper arm (0.15), while in slightly warm conditions with the summer clothes of 0.5 clo, t_nsk could be explained by the weighted mean of instep (0.15), hand (0.17), front thigh (0.19), neck (0.14), low arm (0.20) and upper arm (0.15). The results of this study could guide designs of personal thermal comfort systems by preserving individual body temperature homeostasis.