Field study on thermal comfort in naturally ventilated and air-conditioned university classrooms

Maintaining a satisfactory thermal environment is of primary importance, especially when the goal is to maximize learning such as in schools or universities. This paper presents a field study conducted in Milan during summer 2017 in 16 classrooms of Politecnico di Milano, including both naturally ventilated (NV) and air-conditioned (AC) environments. This study asked 985 students to report their thermal perception and their responses were evaluated according to the measured thermal comfort parameters to assess the prediction as given by Fanger and adaptive models, according to ANSI/ASHRAE 55-2017 and EN 15251:2007 standards. Furthermore, an analysis regarding potential effects of gender in comfort perception was performed. The results confirmed the fitness of Fanger’s model for the prediction of occupants’ thermal sensations in AC classrooms with a reasonable accuracy. In NV classrooms, the Adaptive model was proven to be suitable for predicting students’ comfort zone according to ASHRAE 55 Standard, while the adaptive comfort temperatures recommended by EN 15251 were not acceptable for a large number of students. No significant differences in thermal comfort perception between genders have been observed, except for two NV classrooms in which females’ thermal sensation votes had resulted closer to neutrality in comparison to males, who expressed a warmer thermal sensation.