Abstract: The performance characteristics of twin-screw refrigeration compressor using various refrigerants under part load conditions are investigated by experimental research. At first, based on the recorded p-V indicator diagrams, the various efficiencies of twin-screw refrigeration compressor under part load conditions are analyzed. Then, the effects of four kinds of refrigerant, R22, R134a, R404A and R407C, on compressor performance are presented. As the compressor load falls down, it is shown that the built-in volume ratio is decreased compared to that under full load condition and hence the adiabatic efficiency and adiabatic indicated efficiency of compressor are decreased. However, the PCO coefficient of performance PCO of refrigeration system is improved. By comparing the application part load values VAPL of system, R22 is found to be the best refrigerant with regard to part load operations among the four refrigerants.

Key words: Part load, Performance characteristics, p-V indicator diagram, Refrigerant, Screw refrigeration compressor