Short-term thermal perception and evaluation model under temperature step changes of building transition spaces

Abstract

In summer, the indoor temperature controlled by air conditioning often contrasts significantly with the outdoors. This dramatic temperature change in transitional spaces can cause thermal discomfort. Investigating thermal comfort in response to such step changes in temperature is crucial for ensuring healthy and comfortable indoor and outdoor activities during the summer. This study conducted a summer short-term thermal comfort study in the subway station, which serves as a typical transitional space. The study integrated field measurements, subjective questionnaire statistics, multivariate regression, and hierarchical fitting. Results are as follows: (1) Different exposure sequences had different effects on Thermal Sensation Vote (TSV) and Thermal Comfort Vote (TCV). From hot to cold, TSV showed a stronger correlation with temperature difference, while from cold to hot TSV showed a stronger correlation with temperature threshold. (2) Thermal sensation was more sensitive to wind speed and thermal comfort was more sensitive to humidity in a step change environment. (3) In a dynamic environment, ∆TSV and ∆TCV were synchronized, but TSV and TCV were not themselves synchronized. After the environment gradually stabilized, synchronization disappeared and the predictive ability of TSV for TCV decreased. (4) A thermal sensation model was established, combining ∆TSV and movement distance. This study revealed the factors that influence thermal comfort under step change in transitional spaces and the influencing mechanism of the exposure sequences. It also explored the relationship between dynamic TSV and TCV, providing a theoretical basis for further improving dynamic thermal comfort assessment under sustained step-change conditions.