Critical operating conditions for prevention of frost formation in fin-tube heat exchangers

We obtained the critical operating conditions which prevent frosting in the fin-tube heat exchangers of air-source heat pumps (ASHPs). To accomplish this, we constructed a mathematical model to predict the heat and mass transfer rates of a fin-tube heat exchanger. The mathematical model was verified by comparison with experimental data that showed the heat and mass transfer rates were predicted with an error of less than 10%. According to the mathematical model, if the interface temperature between the air and the cold surface is above the dew point temperature of the air or the freezing point of water, frosting can be prevented. Using this criterion, the critical operating conditions to prevent frosting were established. The frosting and frost-free regions predicted by the model were in good agreement with experimental results. Therefore, these critical operating conditions can be used to provide various operating strategies to prevent frosting in ASHPs.