Performance Comparison among Heat Pump Water Heaters Working with R32, R134a and the Mixture of R32/R134a

摘要

A general air-source heat pump water heater originally designed to work with R134a was reconstructed as experimental rig for performance studies on systems using different refrigerants including R32, R134a and the mixture of R32/R134a which mass ratio is 1:5. Experimental results showed that the power consumption of the heat pump water heater charged individually with R32 would greatly exceed the system's original pre-set maximum input power. When the leaving water temperature was increased from 18°C to 58°C, the average discharge temperature of the heat pump charged with R32/R134a mixture was 13.6% higher than that with R134a. The average power consumption of the heat pump with R134a was 253.5W less than that with R32/R134a mixture. However, the average COP (Coefficient of Performance) obtained by that with R32/R134a mixture was 0.83 higher than that with R134a.