| The parallel flow heat exchanger is a multi-port extruded tube exchanger based on band-tube heat exchanger. It is consist of high performance folded louvered and fins flat microchannel tubes and is featured with small size, low weight, small flow resistance and high thermal efficiency. Nowadays, it has been successfully used in automotive air conditioning and techniques are very mature; there is widespread interest in expanding its applicable range to home air-conditioning.At first, a model was developed for the parallel flow type condenser with the energy balance method. Fluid flow and heat transfer processes in both refrigerant and air sides were analyzed with the latest physical properties database and the corresponding correlations. The study showed that the refrigerant heat transfer coefficient and the pressure drop along the passage vary significantly because of the structural process change of condenser and the refrigerant phase-change. The results of experimental and numerical simulation are compared, and they have good consistency.Finally, it is analyzed that the effect and optimization of speed and fin parameters on the air-side heat transfer and pressure drop to get a new parallel flow condenser. And the effect of micro-channels'hole count and different kinds of flow tube number arrangement on multi-unit parallel-flow condenser are studied. As the increase of micro-channels' hole count, both of the condenser's heat transfer coefficient and the pressure drop are decline. The reasonable tube numbers may increase the ratio of the two-phase region, that augment the effective heat transfer area. |
