Thermal comfort in university classrooms: An experimental study in the tropics

Abstract

Thermal comfort is a paramount objective in university classrooms when the aim is to maximise learning and productivity performance. The challenge to achieve thermal comfort in classrooms in the tropics is even more significant due to the extreme weather conditions and the elevated internal and external heat gains. This study relies on thermal comfort responses from 429 questionnaires collected from December 2017 to January 2018 in three geographic regions in Ecuador. The study compares real thermal sensation and predicted models. The cities and its respective Köppen climate classification are Quito (Cfb), Guayaquil (Aw) and Tena (Af). Several free-running and air-conditioned classrooms were part of the sample in this study. Despite the differences in weather, the building designs and the properties, in terms of materials, are very similar. The Predicted Mean Vote (PMV) and the adaptive methods were used for comparison with actual votes through simple linear regression analysis. Griffiths neutral temperature and the one estimated from regression produce similar results. The neutral temperatures from TSV in Quito, Guayaquil, and Tena were 21.8 °C, 26.3 °C and 26.9 °C respectively. They were aligned to the ones reported in previous studies for locations with similar climate zones. On the other hand, for air-conditioned environments, the PMV model underestimated the occupants' satisfaction with the indoor conditions. Overall, high levels of comfort were observed in free-running classrooms in Quito, regardless of the lower air temperature. Whereas students' preferences in classrooms located in hot-humid climates mechanically conditioned are towards colder environments.