Temporarily occupied space with metabolic-rate-initiated thermal overshoots-A case study in railway stations in transition seasons

Temporarily occupied space (TOS) is defined as an air-conditioned space in which most of occupants stay for less than a certain period (e.g., 40 min), such as post offices, supermarkets, bookstores, and banks. The definition mainly emphasizes two aspects: obvious temperature step up/down and short-term exposure periods. Typical TOSs with predominantly temperature-initiated thermal overshoots have been explored in previous studies. Indeed, apart from temperature-initiated thermal overshoots, thermal overshoots can also be initiated by other parameters, such as metabolic rates. In this view, the definition of thermal overshoots was generalized and a case study was conducted at high-speed railway station in China under conditions of transition seasons. The phenomenon of metabolic-rate-initiated thermal overshoots instead of temperature-initiated thermal overshoots was observed and explored, based on objective measurements and subjective questionnaire surveys. The results could optimize the design and operation of air conditioning and mechanical ventilation (ACMV) systems in such TOSs as embodied by railway stations. In addition, the probit analysis method for analyzing neutral temperature ranges instead of neutral temperature points was also discussed.