LAUSR

Abstract In this study, the thermal comfort of the occupants of learning spaces using three different ventilation strategies (i.e. air-conditioning [AC], hybrid [HB], and natural ventilations [NV]) was investigated at a tropical university campus. Data were collected from 1043 survey questionnaires; concurrently, on-site measurements in three consecutive years were analysed. Findings indicated that HB spaces have significant advantages over AC and NV spaces in terms of a higher rate of neutral thermal sensation votes, temperature satisfaction levels, and overall thermal comfort levels. It was also found that, as compared to those in AC spaces, occupants in HB and NV spaces maintained higher comfort temperature and they could tolerate a wider range of acceptable temperatures. They were also less sensitive to changes in temperature. A significant correlation between the neutral operative temperature and latitude, as identified in existing studies, supports the observation regarding acclimatisation of occupants in warmer climates. The PMV/PPD thermal comfort model predicted warmer thermal sensations than those actually felt by the occupants. The comfort rate estimated according to the PMV/PPD model was consistently lower than that according to the adaptive comfort model in HB and NV spaces, raising concerns about the effectiveness of the PMV/PPD model in predicting thermal comfort in NV spaces in a warm environment. The findings provide convincing evidence to promote the design of HB and NV learning spaces in hot and humid climates. Such ventilation strategies can provide comfortable thermal conditions and, potentially, reduce energy use for cooling and associated CO2 emissions significantly.