Abstract: There is a “breathing effect” in the refrigerating operation of refrigerator, and the air between the inside and outside of the refrigerator will exchange heat and mass with the “breathing effect”. By using CFD, the influence of external airflow changes on the heat exchange of defrosting drainage pipes was studied, and the impact of drain pipe position, air hole direction, etc. on the energy efficiency of frost-free refrigerator was verified through experiments. It has been proved that when the defrosting drain pipe is far from the condenser fan and the air holes are away from the airflow of the condenser fan, it is beneficial to the power consumption of the refrigerator. Compared with being close to the condenser fan and facing the airflow directly, the average annual power consumption can be reduced by approximately 3.10%.

Key words: Refrigerator performance, Frost-free Refrigerator, Drain Pipe, Heat and mass exchange