Sunlight perception and outdoor thermal comfort in college campuses: a new perspective

Abstract

The thermal comfort of outdoor spaces in colleges and universities is crucial for promoting outdoor activities and relieving psychological pressure. To evaluate outdoor thermal comfort from a new perspective, this study investigated subjects' sunlight perception through physical measurements and questionnaires. Sunlight perception was delineated through a combination of subjective assessments and objective measurements. Subjective assessments encapsulated thermal comfort and sensation votes, and sunlight sensitivity. Objective measurements incorporated physical environmental data such as temperature, humidity, wind speed, illumination, and solar radiation. The Universal Thermal Climate Index (UTCI) was used to examine the thermal sensation of subjects under different sun perceptions to reveal the effect of sunshine sensitivity on subjects. The results showed that in terms of subjective perception, the proportion of people who felt hot outdoors increased with the increase in sunlight perception. Additionally, with the change of sunlight perception, the expected temperature of the crowd also changed. As the sunlight perception changed from weak to strong, the desired temperature of the winter population changed from 21.2 °C to 17.7 °C, and the desired temperature of the autumn population changed from 23.8 °C to 19.8 °C. Appropriately increasing shade outdoors in autumn would enhance the comfort of the crowd, while appropriately increasing the light place in the winter outdoors would enhance the comfort of the crowd. These findings provide valuable insights for thermal comfort design and future research in colleges located in cold areas.