Seasonal performance evaluation of refrigeration equipment used for subway train air-conditioning systems

Seasonal performance evaluation of refrigeration equipment used for air-conditioning is to evaluate the comprehensive refrigeration capacity of the air-conditioning system throughout the refrigeration season. Different load characteristics and air-conditioning equipment make the simplification and abstraction methods of seasonal performance indicators different. There are great differences in the operating environment, service time range, and air-conditioning performance characteristics between train air-conditioning and building airconditioning. In order to describe the comprehensive cooling capacity of subway train air-conditioning during the whole cooling season, this study proposes a specific method for evaluating the seasonal performance of the subway train air-conditioning systems under the condition of an air-conditioning bench test. This study first analyzes the construction methods of the typical cooling load model, the running time distribution model, and the performance model of the subway train air-conditioning systems. Then, the specific calculation formulas of seasonal energy efficiency ratio (SEER) are proposed for three common operation forms of subway train airconditioning systems, which are two-compressor fixed-frequency air-conditioning systems, four-compressor fixed-frequency air-conditioning systems, and two-compressor variable-frequency air-conditioning systems, by means of numerical simulation and mathematical derivation. Finally, the real SEER is calculated based on the energy consumption test value for the two-compressor fixed-frequency air-conditioning system. Compared with the real SEER, the relative error of SEERcal obtained by the SEER calculation method proposed in this study is less than 5%, which indicates that the seasonal performance evaluation of refrigeration equipment used for subway train air-conditioning systems is highly accurate.