Entropy generation assessment criterion for compact heat transfer surfaces

A performance assessment method for compact heat transfer surfaces is proposed, consisting of sizing a cross flow heat exchanger for given fluids, temperature and flow rate values. The resulting configuration is then used in a rating routine where only the heat transfer surface type on one exchanger side is modified while maintaining all design parameters constant. Heat exchanger core dimensions resulting from the sizing routine and the reference type on one side of the heat exchanger are maintained as well in the rating procedure, which was repeated for all heat transfer surfaces in the set. Thus, the change in entropy generation rate observed is caused exclusively by changing the heat transfer surface type as no other parameter is modified. This makes possible a classification of a set of heat transfer surfaces based on an entropy generation criterion. The augmentation entropy generation number criterion was adapted to assess and cross check the procedure proposed. Consistency between augmentation entropy generation number criterion and the method proposed was found. The classifications generated by the method proposed were confirmed by augmentation entropy generation number criterion. It was found that the method proposed predicts also the Re value for which an inversion in the classification occurs. The method proposed was implemented for a cross flow heat exchanger type. No other type was studied. A total of 30 heat transfer surfaces of three types, louvered fin, plain fin and strip fin were studied.