Selection Criteria for Plain and Segmented Finned Tubes for Heat Recovery Systems

Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded “plain” fins were generally used in the past, until the high-frequency resistance welding technology permitted a cost-effective manufacture of “segmented” fins. The main advantage of this fin design (Fig. 1) is that it permits higher heat flux and hence smaller, lighter weight units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight, and cost per unit area favor the segmented fin design, a few other considerations such as fouling, ease of cleaning, and availability of dependable design methods have to be considered. This paper analyzes the performance parameters that affect the selection of either fin type.