Abstract: Compressor liquid hammer fault is a key issue that restricts the application of hot gas bypass defrosting technology in household cold products. In order to study the impact of different compressor anti liquid hammer schemes on defrosting performance, two schemes were designed, namely the gas-liquid separation scheme with a liquid reservoir and the compressor self protection scheme, to verify the power consumption, defrosting speed, heat utilization rate, room temperature rise, and other aspects. Verification shows that the self protection design of the compressor has higher defrosting power, higher mass flow rate, and shorter defrosting time compared to the anti liquid hammer method of the reservoir, the defrosting section saves about 8% of power consumption, and the room temperature rebound presents disadvantages, the maximum temperature difference between single point and no-load is about 6℃.

Key words: Hot gas bypass, Defrosting, Compressor liquid hammer, Energy saving