Effect of three air supply modes on water evaporation process in limited space of frost-free refrigerator

Abstract

• Air forced convection in frost-free refrigerator accelerates water evaporation. • The numerical results are in good agreement with experimental results. • The water evaporation rate during on cycle is 20 times of that during off cycle. • Effect of three air supply modes on water evaporation process were analyzed. • The water evaporation rate of annularly blowing air supply mode is the least. The air forced convection is utilized to cool foods in frost-free refrigerator, and it offers uniform temperature field and the fast cooling rate. But the air forced convection also accelerates the water evaporation from foods surface, which leads to foods dehydration. Numerical model of water evaporation process inside refrigerating compartment was validated by experimental results including the evaporated water mass, air temperature and relative humidity during compressor on /off cycle. The air supply modes have effects on velocity and temperature fields inside refrigerating compartment, and three air supply modes were compared: annularly blowing air (ABA) supply, upward blowing air (UBA) supply and forward blowing air (FBA) supply modes. The results show that the water evaporation rate during compressor-on cycle is 20 times of that during compressor-off cycle. The effect of air velocity on water evaporation process is greater than that of vapor partial pressure difference. The water evaporation rate for FBA supply mode is the largest due to its highest air velocity. The water evaporation rate of A B A supply mode is the least because of both its smaller air velocity and vapor partial pressure difference, and it is the best mode to decrease water loss.