CO2, Compressor, Performance Comparision, Single Stage, Two Stage
As a natural refrigerant, CO2 gets more and more attention in recent years. The CO2 system runs at a transcritical cycle. This leads to a high running pressure and high pressure difference for the CO2 compressor. In this paper the single stage and two stage rolling piston compressors with same displacement have been developed for CO2 heat pump water heater. And a comprehensive performance comparison has been made with these two kinds of compressor at different suction pressure, discharge pressure and superheat. With these results, a better understanding for the single stage and two stage CO2 compressors could be got.