Summer thermal environment and energy-saving potential of air conditioning systems in underground railway stations at initial operation stage in Tianjin

Due to the differences in the thermal environment in the underground railway stations during different operating periods, the operation mode of the air conditioning system in underground railway stations at the initial operation stage according to the unified management of existing stations may lead to energy waste. Based on the measurement of the summer thermal environment in public areas and the investigation of relevant system information in the underground railway stations at the initial operation stage in Tianjin, this paper analyses the summer thermal environment characteristics and the energy-saving potential of the air conditioning system in this type of station. The study finds that for the tested station, in the transition season and summer, the air temperature of the outdoor, station hall, platform and tunnel basically decreases, while the relative humidity increases sequentially. The air conditioning temperature in the station in summer is much lower than the design value.The specific enthalpy of the air in the tunnel is lower than that of outdoor air. It can potentially be used as a natural cold source. It is estimated that at the summer outdoor air design temperature, the energy-saving caused by the tunnel infiltration air is 2 011.03 kWh per working day. Based on the research results, this paper also proposes the corresponding energy-saving suggestions.