The study of dynamic characteristics on a novel air source heat pump coupled with liquid-storage gas-liquid separator under non frosting and refrigeration conditions

Abstract

Air source heat pump is widely used for heating as it has high efficiency and environmentally friendly advantages, but there is frosting issue in low temperature and high humidity conditions. In order to improve the performance of air source heat pump (ASHP) when its evaporator is subject to frosting, a novel ASHP system coupled with liquid-storage gas-liquid separator was proposed in previous work, which was conducted at a constant temperature. However, the environment temperature is variable during the actual operation, the influence mechanism of the temperature change on the dynamic characteristics of the system and operation characteristics is still unclear. Therefore, experimental method is employed in this work, the aim is to investigate the dynamic performance of the novel ASHP in heating and refrigeration modes in actual environment, including suction/exhaust pressure, suction/exhaust temperature, inlet/outlet water temperature, the coefficient of performance (COP) etc. to improve the adaptability of the heat pump unit. The results indicate that the COP is 2.78–3.49 when the ambient temperature is 6.5–12.5 °C under the heating condition. Also, in refrigeration mode, the COP of the system is 3.28–3.04 under the ambient temperature of 22∼38 °C. This study shows that the novel ASHP has a good dynamic performance during heating/cooling operation in the actual environment. Also, some suggestions for improvement are put forward to solve the existing problems in this work.