Performance comparison analysis between water-cooled direct refrigeration air conditioning system and traditional air conditioning system in subway stations based on long-term field measurement

At present, the application of water-cooled direct refrigeration air conditioning systems to domestic subway stations is gradually increasing, and there is a trend to replace the conventional water-cooled air conditioning system. For water-cooled direct refrigeration air conditioning systems, past researches have generally focused on theoretical analysis or laboratory analysis, lacking actual measurement analysis and comparison of actual application conditions. This paper analyses the performance differences between the two air conditioning schemes and the key factors affecting the performance of the water-cooled direct refrigeration air conditioning system through long-term testing of typical stations with water-cooled direct refrigeration air conditioning systems and conventional water-cooled air conditioning systems. It is found that the actual operating effect of the water-cooled direct refrigeration air conditioning system is better than that of the conventional water-cooled air conditioning system, but there is a significant difference in operating conditions between daytime and nighttime. At the same time, the two important factors affecting the performance of the chiller are the increase in the load rate and the decrease in the cooling water return temperature, which are more beneficial to the water-cooled direct refrigeration air conditioning system. According to the test results, the targeted suggestions are provided for the design of the air conditioning system in future subway stations.