EXPERIMENTALLY VALIDATED MODEL FOR FROSTING OF PLAIN-FIN-ROUND-TUBE HEAT EXCHANGERS

A quasi-steady finite-volume model was developed for modeling a plain-fin-round-tube heat exchanger under frosted conditions. It was validated by comparing with the wet-and-dry surface experimental observations (medium and low temperature applications) of total, sensible and latent heat transfers, air-side pressure drop, and frost deposition. In general good agreement was obtained between the model predictions and experimental observations within the range of experimental uncertainty. The results demonstrate that at one time step correlations for frost density and conductivity can be combined with j and f-factor correlations and heat and mass transfer equations to predict frost distribution patterns which in turn can be used at the next time step to update the local fin thickness used to calculate heat and mass transfer and air-side pressure drop. The model could be further extended to simulate direct expansion evaporators with varying operating conditions and variable heat exchanger geometry.