A new model to measure the performance of the fins based on exergy analysis

Abstract

Currently, two basic measures performance models are conventionally defined to evaluate the performance of the extended surfaces or the fins. First is the fin efficiency that is defined as the ratio of actual heat transferred by a fin to heat that would be transferred if the entire fin were at base temperature. Second is the fin effectiveness that is defined as the ratio of heat flux from the wall with the fin to heat flux from the wall without the fin. In the present work, a new criterion is proposed to measure the performance of the fins. The new criterion is defined as the ratio of exergy of convective heat transferred by the fin to the irreversibility of the fin. The new criterion named fin ecological coefficient of performance (ECOPf) based on the Second law of thermodynamics whereas the fin efficiency and fin effectiveness carried out by the First law of thermodynamics. A code has been developed using these models to compare the performances of a typical fin with respect to the fin parameters and cooling fluid. According to the results, it can be concluded that the ECOPf model is a rational criterion rather than two other models. In addition, since ECOPf model considers the irreversibility of the control surface so it is a better measuring performance model in new fin design.