Enhanced heat transfer in air-conditioner heat exchanger using superhydrophobic foils

Air-conditioners have the highest energy consumption among the household appliances because of the improved thermal resistance by the filmwise condensation in summer and frosting in winter on the surface of hydrophilic foils of heat exchanger. The wet foils are also easy to adsorb dirts and reproduce bacteria, further affecting people health in the room. Here, through chemical oxidation and subsequent chemical modification, we fabricated superhydrophobic nano-arrays on the packed aluminum-foils and then assembled a novel air-conditioner heat exchanger using the foils. The foils showed high performance in self-cleaning, anti-condensation, anti-frosting, anti-corrosion and environment stability, promising a good candidate for improving energy efficiency of air-conditioners in future. The results of testing revealed that the cooling capacity and heat transfer coefficient from superhydrophobic heat exchanger increasing over 8 and 2 percent than conventional hydrophilic one under rated output working conditions. Moreover, the superhydrophobic exchanger under the condition of frosting has higher energy conversion (over 85%) than the conventional hydrophilic one after 60 min.