A Thermal Comfort Field Study of Naturally Ventilated Classrooms during Spring and Autumn in Xi’an, China

Abstract

Thermal comfort in natural ventilated university classroom in Xi’an during transition seasons in autumn (November 2017) and spring (April 2018) was studied in this paper. Field experiments were carried out in the typical teaching buildings in Xi’an Jiaotong University. Indoor thermal environment parameters, including air temperature, black globe temperature, air velocity, and relative humidity, were continuously measured during classes. At the same time, the subjective questionnaires were used to acquire students’ thermal sensation, thermal preference, and thermal acceptability. 1686 valid questionnaires were received. Results showed that the neutral temperatures of autumn and spring are 20.6 °C and 23.2 °C, respectively, while the preferred temperatures are 22.8 °C and 23.8 °C. The thermal acceptability in all the cases measured in both seasons exceeded 80%. Due to the limitation of the adaptation behaviors of the students in classes, the adaptive predicted mean vote (aPMV) model, which is used to determine the thermal comfort in free-running buildings in China, predicts lager comfort temperature zone than the experimental results.