One simple way of increasing the heat transfer for a fin-and-tube heat exchanger is to increase the fin surface area. In this study, a series of tests were conducted on wide slit fin heat exchangers having an increased fin area (Pl/Pt = 0.87), and the results were compared with those of standard slit fin heat exchangers (Pl/Pt = 0.6). Thermal performances of wide silt-finned samples were superior to those of standard slit fin samples. For one row configuration, the j factor of the wide slit fin sample was 11% larger, and the f factor was 33 % smaller than those of the standard slit fin sample. The difference decreased as the number of tube row increased, although wide slit fin sample always yielded superior performance, The reason was attributed to the many narrower slits formed on the wide fin sample. Furthermore, the effect of fin pitch on j and f factor was not significant, and j factor decreased with the increase of the number of tube row.

• 김내현 | Nae-Hyun Kim Corresponding Author