Local frost behaviors of a scaled-up louvered fin heat exchanger

Abstract

We investigated the local frost growth in a louvered fin heat exchanger using a scaled-up model and analyzed the characteristics of frost behaviors and variation in the heat transfer rate according to frost formation compared to a flat-fin heat exchanger. In contrast to a uniform frost layer of the flat-fin heat exchanger, highly non-uniform frost layer between the front and rear sides was observed on the louvered fin heat exchanger. The heat transfer rate of the louvered fin heat exchanger more rapidly decreased with the frost formation than that of the flat-fin heat exchanger. The blocking of the spaces between the louvers on the front side by frost mainly induced the significant decrease of the heat transfer rate of the louvered fin heat exchanger. On the louvered fin front side, the spaces between the louvers near the redirection region were first blocked by frost formation before those near the air inlet region due to the higher mass transfer driving force around the redirection region. Once the louvered fin front side was totally blocked by frost, the louvered fin rear side did not effectively work anymore.