Optimization of air operating temperature in subway stations in high temperature days based on actual measurement and questionnaire

This paper presents a method for calculating the air operating temperature of subway stations based on the relative warmth index (RWI) in high temperature days. While testing the thermal environment parameters in a subway station in Shanghai, the thermal comfort survey questionnaires are simultaneously distributed in the station hall and platform. The questionnaires with comfortable thermal sensation are selected to determine the recommended air operating temperatures of the station hall and platform according to the minimum difference of RWI between the outdoor and the station hall, and between the station hall and the platform. The results show that when the relative humidity of the station is 40% to 70%, the recommended air operating temperature of the station hall and platform can reach 32.6 ℃ and 31.1 ℃ respectively when the outdoor temperature is 35.0 ℃ to 36.0 ℃, and 33.3 ℃ and 31.9 ℃ respectively when the outdoor temperature is 36.0 ℃ to 37.0 ℃. This article recommends that the air operating temperature of the station meets the needs of passengers entering the station hall from the outside and entering the station platform from the station hall for “short-term comfort”. At the same time, higher station air operating temperature is of great significance to the energy saving of the air conditioning system.