An Experimental Study of the Refrigeration Characteristics of Commercial Air Source Heat Pump Units

Based on the theory of quasi-two-stage compression, a theoretical analysis and an experimental test of an air source heat pump chiller and water heater with R410a as refrigerant were carried out by means of medium-pressure air tilling and an enthalpy increasing measure. The experimental results showed that under an environment temperature rise of 21 degrees C to 50 degrees C cooling conditions system capacity, exhaust temperature and exhaust pressure increased. As compared to the standard operating mode of 50 degrees C high-temperature environment refrigerating capacity where exhaust temperature and pressure fell by 26.55% and 37.8%, respectively, those of the former rose by 33.69% and 26.44%, respectively. Thus, a supply of medium-pressure air could reduce exhaust temperature and improve system cooling capacity. Moreover, at the refrigeration 50 degrees C high-temperature conditions, the medium-pressure air compensating model increased exhaust temperature by not filling gas from 111.9 degrees C to 106.23 degrees C, while it simultaneously increased the capacity by 13.5%.