Heat Transfer and Pressure Drop Characteristics of Plain Fin-and-Tube Heat Exchangers Having 5.0 mm Tubes Under Dehumidifying Condition

Abstract

In this study, wet surface pressure drop and heat transfer characteristics of plain finned heat exchangers having 5.0 mm diameter (5.3 mm after tube expansion) tubes were investigated. Nine samples having different fin pitches (1.1 to 1.3 mm) and tube rows (1 to 3 rows) were tested. The fin pitch had a negligible effect on j and f factors. Both j and f factors decreased as the number of tube row increased. When compared the j and f factors of the samples having 5.3 mm diameter tubes with those of 7.3 mm diameter tubes, 5.3 mm samples yielded higher j factors and lower f factors. The j/f ratios of 5.3 mm samples are larger than those of 7.3 mm samples which implies that 5.3 mm geometry is more beneficial than 7.3 mm geometry.