Experiment on accelerated defrosting of quasi-two-stage compressed air-source heat pump with flash tank

In order to improve the performance of reverse cycle defrosting of a quasi-two-stage compressed air-source heat pump with the flash tank, this paper uses the existing cycle structure of the unit to realize vapor injection by opening the solenoid valve during defrosting and increase the refrigerant mass flow. The experimental results show that vapor injection can reduce frost melting time, thus effectively reduce defrosting time and defrosting energy consumption, and the lower the outdoor temperature is, the more significant the effect is. In the experimental environment of -10 ℃ to 2 ℃, the defrosting time is shortened by 23.73% to 40.48%, and the defrosting power consumption is reduced by 17.75% to 45.90% after using vapor injection defrosting.