Alternate Methodology for Air Conditioning Compressor Capacity Measurement

The actual compressor capacity is generally different from the theoretical capacity due to internal leakages and manufacturing imperfections. Conventionally, compressor volumetric efficiency is measured using system level testing consisting of evaporator, condensor & TXV in a closed loop system with known refrigerants. In this paper a methodology is demonstrated for evaluating any auto mobile air conditioning compressors' volumetric efficiency & capacity by using atmospheric air in an open loop system. Wide range of compressors (~70cc to ~220 cc) were tested and data generated. The process parameters of the test rig was continuously monitored until stabilization and readings were taken. It is observed that the results are comparable with closed loop performance results. Comparative study is presented for tested volumetric capacity and theoretically calculated value along with variations. Henceforth, the outlined approach gives deeper insight into design effectiveness, any imperfections or variations. This testing process is cost effective, reliable, simpler and with a shorter testing period. The extended application of this test rig is to evaluate performance characteristics of variable displacement compressors along with troubleshooting of electronic control valve.