Study on outdoor thermal comfort of factory areas during winter in hot summer and cold winter zone of China

The factory area is an important part of the city. Its environment is relatively simple, mainly with large plant buildings and less vegetation, which is easy to form an extreme outdoor thermal environment. However, few studies have focused on how these changes affect outdoor thermal comfort in factory areas. In this study, through field meteorological measurements and questionnaire surveys, outdoor thermal comfort of different built environments in two factory areas in Haining, China, located in the hot summer and cold winter zone, was studied in winter. Combined with thermal comfort indices Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI), 12 observation sites in factory areas were analyzed to establish the outdoor thermal benchmark suitable for the factory area. The results show that: (1) Thermal comfort was strongly related to thermal sensation. (2) Air temperature and globe temperature were two primary factors affecting workers' thermal sensations. In addition, thermal sensation was negatively correlated with wind speed and relative humidity. (3) The built environment had a significant influence on human thermal sensation and thermal comfort; sky view factor was an important morphology parameter that affected outdoor thermal sensation, and the outdoor thermal sensation improved as it increases. (4) Neutral temperatures of PET and UTCI were 14.3 °C and 15.8 °C; neutral PET range and neutral UTCI range were 10.7–17.8 °C and 12.2–19.4 °C, respectively. These findings could serve as theoretical baselines and guidelines for factory area design.