Effects of surface wettability and defrosting conditions on defrosting performance of fin-tube heat exchanger

Defrosting performance is closely related to surface wettability and defrosting conditions. In this paper, the effects of surface wettability, initial frost mass and defrosting temperatures on defrosting performance of fin-tube heat exchanger were studied experimentally. The contact angles of hydrophilic, bare and superhydrophobic heat exchangers were 13.7°, 95.3° and 156.8°, respectively. Five parameters were defined to provide quantitative analysis of the defrosting performance. Defrosting performance is greatly affected by surface wettability. The superhydrophobic heat exchanger has the best defrosting performance followed by the hydrophilic one. Initial frost mass and defrosting temperature have different levels of influences on different heat exchangers. For example, the retained water mass on the bare heat exchanger increases by 62.2% when the frosting time increases from 30 min to 90 min, while it has little change on the superhydrophobic one. And the defrosting temperature has no influence on retained water mass of each heat exchanger.