Thermal comfort condition during day and night.

Abstract

8 women and 8 men each participated in two comfort experiments. One experiment took place at the time of the day when the rectal temperature was maximum, and the other experiment took place at the time of the night when the rectal temperature was minimum. The exact times at which the maximum and minimum body temperatures occurred were determined for each person in pretests. In each comfort experiment (2 1/2 hrs) the preferred ambient temperature was determined for each subject by adjusting the ambient temperature according to his wishes. The subjects were sedentary. Skin temperatures, rectal temperature, metabolic rate and evaporative weight loss were measured. The rectal temperature and the mean skin temperature at which the subjects felt comfortable were 0.4° C lower in the night experiment than in the day experiment. But due to a slightly lower metabolic rate at night this did not cause the subjects to prefer a different ambient temperature at the two points of time. This indicates that the same thermal comfort conditions can be used independent of the time of day or night.