Abstract: Experimental studies on the air-side heat transfer and pressure drop characteristics for 16 types offset strip fin heat exchanger and flat tube heat exchangers were performed with such parameters as fin space s, fin height h, fin thickness t, fin length l and flow length d.A series of tests were conducted at air side Reynolds number of 500—7500,and constant tube-side water flow rate of 2.5 m3·h-1.The air side thermal performance data were analyzed by using the effectiveness-NTU method.The heat transfer coefficients and pressure drop data for different fin space s and fin length l were reported in terms of frontal air velocity.The general correlations for j and f factors were derived by regression analysis and F significance test,and the correlations had a RMS error of ±10%.The absolute mean deviations for the j and f factor correlations were 4.2% and 5.3% respectively.