Effects of coupled accumulator with gas-liquid separator on an air source heat pump

The outdoor heat exchanger is easy to frost when an air source heat pump (ASHP) is heating in winter. As the most common defrosting method, reverse cycle defrosting (RCD) has the problems of defrosting with liquid and long-time defrosting. To better solve the problem of RCD, a novel ASHP coupled with coupled accumulator with gas-liquid separator is proposed. A mathematical model of coupled accumulator with gas-liquid separator was established to simulate the influence of inlet temperature of gaseous and liquid refrigerant, the influence of heat transfer area of the coupled accumulator with gas-liquid separator on COP, and the influence of outdoor air temperature and humidity on frost thickness. Results show that the heat transfer effect in the coupled accumulator with gas-liquid separator is better when the outdoor air temperature is 5°C and the relative humidity is 90%. When the heat transfer area in the cavity of the gas-liquid separator is larger than 0.18m2, the COP increases slowly. The frost thickness reaches the maximum when the outdoor air temperature is 5°C and the relative humidity is 90%.