Impact of Variable Geometry Micro Channel Heat Exchanger on Tube and Fin in an Automotive Air Conditioning

Abstract

The primary objective of this study is to enhance condenser performance by employing innovative tube and port shapes that regulate the refrigerant volume, in conjunction with variable fin geometry. The aim is to comprehensively investigate the influence of refrigerant and air-side heat transfer coefficient (HTCs). Analytical calculations were conducted for both fin and tube geometries and the results were juxtaposed with findings from both CFD simulations and experimental setups. Furthermore, as an initial step, the analytical calculations delved into the effect of two-phase density on refrigerant-side heat transfer. These analytical results were cross-referenced with CFD simulations and experimental data and they were found to fall within a correlation range of 10%. It is worth noting that the rectangular tube shape, while boasting a lower pressure drop, exhibited a relatively lower HTC. Conversely, the hexagon model demonstrated a higher pressure drop, coupled with a higher HTC. The configuration of a hexagon with rectangular ports, coupled with the precise selection of fin geometry, yielded superior results when compared to other shapes, such as rectangular and oval tubes. These results highlight the feasibility of using analytical methods in the initial design phase of automotive product development. Subsequently, these analytical findings can be correlated with experimental data, offering potential cost savings in prototype part development and reducing the lead time to market.