Effect of inclination on thermal performance of a louver-finned aluminum heat exchanger having a drainage channel

Heat exchangers are frequently installed at an inclined angle to reduce the height of the air-conditioning unit. The inclination may deteriorate the thermal performance of the heat exchanger, and the effect will be more severe for an aluminum heat exchanger compared with a conventional fin-and-tube heat exchanger. However, the literature shows very limited investigations on this subject. In this study, a series of tests were conducted for a newly-developed aluminum heat exchanger, which has an additional drainage channel at downstream of the fin. Results showed that the pressure drop increased as inclination angle increased. However, the heat transfer coefficient showed a minimum behavior at approximately 45° inclination angle. This was true both for dry and wet conditions. The effect of inclination angle on the ratio between wet and dry j and f factor was not significant, which suggested that the inclination did not alter the condensate pattern on the louver fin (louver-bridging, fin-bridging, etc.) significantly. Comparison of the thermal efficiency indices ( j/f 1/3 ) of the present sample with those of the conventional sample (having no drainage channel) showed that the thermal performance improvement is significant under wet condition, which confirms the excellent condensate drainage of the present sample.