Novel Approach Development for Air Conditioning Compressor Capacity Measurement

The actual compressor capacity is generally different from the theoretical capacity due to internal leakages, losses and manufacturing imperfections. Conventionally, compressors’ volumetric efficiency and compressor capacity is measured using system level (calorimeter) testing consisting of evaporator, condensor and TXV in a closed loop system with known refrigerants (R134, R1234yf etc.). In this paper a novel methodology is demonstrated and test rig developed for evaluating any automobile air conditioning compressors’ actual volumetric efficiency and capacity by using working fluid as atmospheric air in an open loop single phase system. Compressor of theoretical capacities 90, 110, 125, 140, 150 cm3/rev were tested and actual capacities were measured at different pressure ratios and compressor RPMs. The process parameters of the test rig were continuously monitored and readings were taken through data acquisition system. Comparative study is also presented for tested volumetric efficiency and compressor capacity through novel approach with calorimeter testing results. Hence the outlined approach gives deeper insight into design effectiveness, any imperfections or variations. This testing method is cost effective, simpler and with a shorter testing period w.r.t. conventional calorimeter test method. Due to shorter stabilization time and testing duration this novel method is convenient to use to test and control the actual capacity variation at mass production level also.