Frost on a simple fin-tube under heat pump condition.

This study measures the frost thickness and frost mass on a flat plate and on a circular tube to propose the correlation equations for the local and average frost thickness, frost density, and frost mass. Key parameters were the cooling surface temperature, absolute humidity of air, air temperature, and air velocity. A 50% ethylene glycol aqueous solution was applied as a coolant. The study also measured the frost thickness and the frost mass on a fin-tube to compare the predicted values on the fin of the fin-tube by the correlation equations for the flat plate and the circular tube. Correlation equations for the local and average frost thickness and frost mass under the heat pump condition were proposed. The values predicted by the correlation equations under the freezer condition showed larger by the maximum of 30-50% than the values predicted by the present correlation equations under the heat pump condition. The empirical correlations under the heat pump condition in the present study might predict more accurately than the other correlations. The proposed correlation for the frost thickness agreed with the measured data within 5% and the proposed correlation for the frost mass agreed with the measured data within 10%.