Effect of Fin Type on Performance of Compact Heat Exchangers with Mini-Channel

Abstract

A comparative investigation is carried out to reveal the effect of plate-fin type variation on the performance of compact heat exchangers (CHX) with a mini-channel flat tube. The CHX prototypes with plain, louver, and offset strip fins with the same frontal area are tested in the same air tunnel under the same experimental conditions to provide a better comparison. Besides the typical performance measures namely Colburn j-factor, friction, and volume goodness factors, some rarely chosen measures are considered as well, such as the core volume goodness factor to evaluate the performance of the prototypes from all aspects. Due to the nature of the mini channel flat tubes, the flow depth is very narrow and one of the targets is to understand the importance of the fin-type on the performance in such a short flow depth. As regards to the outcomes, the CHX with plain fin shows better performance when it is evaluated by the typical approaches which is presented with respect to Reynolds number but when the compactness is considered in performance evaluation, CHX with louver fins achieves higher heat transfer indexes than other fin geometries.