Thermal Comfort In University Classrooms In Frosty Area

With the developing of the economy and advancement of the society, more and more researchers begin to put their eyes on the thermal environment in classrooms. There is high occupant density in classrooms and the students' unsatisfactory thermal sensation would have negative influences on their studying efficiency. A field study was conducted in university classrooms in Harbin during the heating time. Both field measurements and subjective surveys were performed at the same time during the investigating time.A chi-square test was applied to find the significant aspects that affect subjects' thermal sensation votes. The results show that gender, origin place of the subjects and air temperature have significant influence. Three methods were conducted to judge the thermal acceptability of the subjects in winter, the results show that these three methods had significant difference. The comfort temperature zone obtained in this study was 19.6℃～24.3℃, and that was boarder than other zones which were obtained by the foreign researchers. The thermal sensation model in the classrooms in winter was built. After comparing the neutrality temperature with the preference temperature, the result show that the preference temperature was higher than the neutrality temperature. Moreover, female's neutrality temperature and preference temperature was higher than male's value, respectively.After researching the IAQ problem of the classrooms in winter, the results show that the CO₂ concentration in the lower floors was universal lower than in the higher floors, and the occupant density had influence on the value of the indoor CO₂ concentration. Moreover, a subjective investigate was conducted to judge the IAQ, the results show that gender has no significant influence on the judging.After comparing the field study results between winter and spring, the results show that the preference temperature in spring is 0.6℃lower than in winter, and is 0.91℃lower than the mean indoor temperature in spring. Moreover, after conducting a chi-square test on the thermal sensation and air-clear sensation in different season, the results show that there is a significant difference in subjects' thermal sensation and their judge on IAQ between spring and winter.