Hydrophilic treatment and performance evaluation of copper finned tube evaporators

A surface treating method was developed to improve the surface wettability of a copper finned tube evaporator. The treatment was done by immersing the evaporator in a sodium hydroxide (NaOH) and potassium persulphate (K2S2O8) mixed solution for a certain length of time. Cooling performance tests were conducted on two evaporators, which included an untreated and a hydrophilically treated copper fin evaporator. Each evaporator was tested with it being installed in the indoor unit of a cabinet-type air conditioner. Tests were carried out using the calorimeter method at an indoor air temperature of 27 °C for three indoor air relative humidities of 20%, 47% and 78%. The experimental results show that the surface treating method developed in this research is an effective means to promote the surface wettability of a copper finned tube evaporator, and the hydrophilically treated evaporator tends to yield a greater cooling capacity than the untreated evaporator.