The air-side heat transfer and friction characteristics of two fin-and-tube heat exchangers having different types of waffle configuration was experimentally explored. The Colburn (j factor) and Fanning friction factors (f) were applied to describe airside heat transfer and friction characteristics. The effects of fin type on the air-side performance of smooth wave fin-and-tube heat exchangers were analyzed. When the Reynolds number exceeded 5500

the j factor of the two heat exchangers differed by more than 6.4%

and the f factor differed by 7.8%. The predictions of 34 existing experimental correlations were verified and the results demonstrated that they exhibited a large deviation. A multiple linear regression technique was used to develop new heat transfer and resistance correlations. The mean deviations of the new correlations were 1.59% and 6.75% respectively. The distribution of deviation was uniform

and prediction accuracy was significantly higher than that of the existing correlations.