Four kinds of body temperatures and their relationships with thermal perception.

Body temperature serves as the principal factor in thermal perception determination. Current thermal comfort researches mainly focused on skin temperature, while other kinds of body temperatures were often ignored. In laboratory with strictly controlled environment, 26 subjects (13 males and 13 females) remained seated for a duration of 130 min in two thermal environments (19 °C and 35 °C), arranged in a particular order; four kinds of body temperatures (skin temperature, oral temperature, auditory canal temperature and breath temperature) and three kinds of thermal perception votes (thermal sensation, thermal comfort and thermal acceptable) were regularly collected. The analysis results showed that, skin temperature and breath temperature significantly changed with ambient temperature (p < 0.001); the difference between average value of core temperature in two conditions was small (≤0.3 °C), but a significant difference was almost observed in auditory canal temperature of males (p = 0.07). Both skin temperature and breath temperature were significantly related with three subjective votes (p < 0.001), meanwhile, the prediction accuracy of breath temperature for thermal perception was in no way inferior to skin temperature. Although oral temperature and auditory canal temperature had partial significant correlations with thermal perception, they were difficult to be carried out in practical application due to their weak explanatory powers (correlation coefficient <0.3). In summary, this research tried to establish correlation laws between body temperatures and thermal perception votes during a temperature step-change experiment, while finding the potential of utilizing breath temperature for thermal perception prediction, which is expected to be further promoted in the future.