Temperature-gradient-enabled prohibition of condensation frosting on fin surfaces

Condensation frosting on fin surfaces has long been considered a challenging issue for heat exchangers (e.g., in air conditioners). Superhydrophobic/omniphobic surfaces have been exploited for passive surface anti-icing/-frosting, but the results show that the ice nucleation and frost propagation are merely delayed and only short-term prohibition can be realized. Here, we propose an alternative strategy to enable efficient and long-lasting frost prohibition by enhancing the inherent temperature gradient (TG) along a fin rather than modifying surface properties. At a fin base temperature of −10°C, we identify an ∼34% reduction of the long-term frosting area with ∼96% heat transfer enhancement by enhancing the dimensionless TG from ∼0.2 to ∼0.4. The surface modification can be incorporated with a tailored TG to get better frost-prohibition performance over the whole process. The finding of this work sheds light on a simple yet effective approach toward long-term anti-frosting for finned-tube heat exchangers and thermal management devices.