A review of dynamic thermal comfort influenced by environmental parameters and human factors

Dynamic thermal comfort refers to the environmental condition with non-constant parameters, which has attracted more concerns compared with steady-state thermal comfort because of its benefits on human satisfaction, energy efficiency, and body health. This study reviewed over 100 relevant papers in this field to gain a comprehensive understanding of dynamic thermal comfort. Firstly, the dynamics of environmental parameters were analyzed mainly from two aspects, changes in air temperature and variations of airflow. All conditions of air temperature step change were concluded, and the comparison of dynamic airflow was from air velocity, wind volume, air speed, wind direction, pulsation frequency, and turbulence. Then, changes of metabolic rate were discussed as the typical human-related factor which influences the variation of thermal comfort significantly in reality. After that, the thermal history and thermal adaptation involved in dynamic scenarios were further analyzed. A classification method based on different time scales was proposed to illustrate the development of thermal adaptation. Also, the models for dynamic thermal comfort and the concept of thermal alliesthesia were discussed. It proved that the rational dynamic strategy could effectively enhance human thermal perception and be beneficial to energy conservation of air conditioner, and the subjective changes of human activity and behaviors also had great influences which could not be neglected. This paper could provide a reference for systematically understanding dynamic thermal comfort through its theory, models, and application, and also help in understanding the mechanism of thermal adaptation.