Feasibility study of a novel defrosting method for air source heat pumps.

The frost grows on the surfaces of the condensate droplets which appear at the initial stage of the frosting process. If the initial condensate droplets can be removed before they froze, the process of the frost layer growth will be cut off. Therefore, this paper puts forward a novel defrosting method for air source heat pumps based on the evaporation of the initial condensate droplets by hot air. The evaporation efficiency of the condensate droplets on fins with different surface characteristics (hydrophilic, bare and superhydrophobic) are investigated and compared experimentally under different temperatures and velocities of hot air. The hydrophilic and superhydrophobic fins showed high evaporation efficiency. Moreover, most of the initial condensate droplets on superhydrophobic surface were instantaneously shed by the wind force. Experimental results indicate that the novel defrosting method is feasible with the advantages of low energy consumption and short time.