The wet performance of microchannel heat exchanger (Fin Pitch=1.1mm) with hydrophobic

hydrophilic and without surface coating were studied under different conditions experimentally. The results indicated that hydrophobic surface coating had bad effects on air side performance: the capacity decreased by 14% under low air velocity and the decrease became less with the increase of air velocity; the pressure drop increased at least by 130% under different conditions except the condition of high air velocity & humidity. The capacity of hydrophilic heat exchanger decreased by 2%-8% under different conditions; the pressure drop decreased up to 50% under high air velocity & humidity and got improved under most conditions except for the 17% decrease under the condition of low air velocity & high humidity. Air side performance of microchannel heat exchanger with hydrophilic and without surface coating were studied after 260h salt spray corrosion. The capacity of hydrophilic coating heat exchanger increased by 4%-6% compared to the one without surface coating

and pressure drop decreased by 14%-16%. The result indicated that hydrophilic coating was good for anti-corrosion.