ASSESSMENT OF CALCULATION METHODS FOR EFFICIENCY OF STRAIGHT FINS OF RECTANGULAR PROFILE

Fin efficiency evaluation of plate-fin surfaces in compact heat exchangers is done based on the idealizations of one-dimensional analysis, uniform thickness thin fins, uniform fin thermal conductivity, uniform heat transfer coefficients, uniform temperature ambient, and no temperature depression at the fin base. A critical assessment of these idealizations is presented. Whenever possible, additional quantitative new results are obtained to account for some of these effects. Relaxation of these idealizations will lower the value of ideal one-dimensional fin efficiency, but will have a relatively small effect, if the fin efficiency is above about 80 percent, based on the assessment in the paper. Some specific design recommendations are made for the determination of the fin efficiency for plate-fin heat exchangers.