Evaluating thermal comfort indices for outdoor spaces on a university campus.

This study evaluates the applicability of three thermal comfort indices-Physiologically Equivalent Temperature (PET), Standard Effective Temperature (SET), and Universal Thermal Climate Index (UTCI)-in various outdoor environments on the campus of Xi'an University, China. Meteorological data were collected on sunny days using a portable weather station at a height of 1.5 m, and subjective questionnaires were administered to 25 healthy university students over three months to gather Thermal Sensation Votes (TSV) and Thermal Comfort Votes (TCV). The study was conducted at four distinct outdoor locations: a lakeside area (Location 1), a shaded path (Location 2), a sports field (Location 3), and a plaza (Location 4). PET, SET, and UTCI values were calculated from the collected data using Rayman software. The analysis revealed significant differences in thermal comfort across the four locations, with the highest proportion of subjects feeling hot at the sports field (54.4%) and the highest proportion feeling cold at the lakeside (39%). The shaded path had the highest proportion of subjects feeling comfortable (79.4%), while the lakeside had the lowest (60.1%). The results indicated that SET underestimated thermal sensation at Locations 1, 3, and 4, necessitating calibration. PET was suitable for Locations 2, 3, and 4 but failed to reflect the thermal sensation at Location 1 due to prolonged sun exposure. In contrast, UTCI demonstrated applicability across all locations. To enhance accuracy, revised indices SET' and PET' were formulated using the mean-median method, providing more precise thermal comfort assessments. These findings underscore the limitations of SET and PET under specific conditions and highlight the robustness of UTCI, offering valuable insights for urban planning and design aimed at improving outdoor thermal comfort and well-being.

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

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.