Numerical simulation of heat reflux of air conditioning condensers in metro trains

Taking a metro station in China as the research object, this paper uses the STESS software and PHOENICS software to simulate and calculate the problem of condenser heat reflux problem during the stopping period when the station heat exhaust system is turned on and off, respectively. It is found that the condenser inlet air temperature is high in the middle and low at ends, which indicates that the condenser exhaust air heat reflux is the most serious in the middle and weaker at the ends. When the thermal exhaust system is turned off, the average condenser inlet air heat reflux rate is 64%, and after the station exhaust system is turned on, the heat reflux rate is reduced to 56%, which indicates that opening the thermal exhaust system can effectively eliminate the train condenser exhaust heat, reduce the exhaust air heat reflux, and effectively avoid the problem of train air conditioning shut down due to the high temperature of the condenser inlet air. This paper gives the proportion of the condenser inlet air from the condenser outlet air, tunnel air and station air of each condenser of the train. According to the theoretical and measured temperature and other parameters, the average inlet temperature of the condenser is calculated, and compared with the measured data, it verifies the accuracy of the simulation calculation. In addition, the actual temperature of the condenser inlet air can be calculated according to the temperature of the condenser outlet air, the tunnel air and the station air, so as to guide the design and operation of the heat exhaust system, which has certain significance for reducing the operating energy consumption of the thermal exhaust system.