Thermo-Hydraulic Performance Analysis of a Microchannel Flat-Tube Heat Exchanger with Finned Enhancements

The present study investigated the thermo-hydraulic characteristics in a microchannel heat exchanger that has a capacity of 2.6kW with the surface area of 2.5m2 configured with finned and microchannel flat tubes. The analysis covers both analytical and comprehensive experimental evaluations of the heat transfer characteristics and pressure drop phenomena. Two fluids (water and air) were assumed to have constant properties. Parameters such as the total pressure drop, the actual effectiveness, the NTU effectiveness, the rate of heat transfer, the heat flux, the log-mean temperature difference, the overall heat transfer coefficient, and the performance index were determined. At the inlet water temperature of 60°C, the actual effectiveness decreases from 90.5% to 74%; the NTU effectiveness decreases from 82.4% to 61.3%; the heat flux increases from 632.6 W/m2 to 943.9 W/m2; the log-mean temperature difference increases from 9oC to 10.3oC, calculating the overall heat transfer coefficient increases from 70.1 W/m2K to 92.1 W/m2K as rising the water velocity from 0.488 m/s to 0.975 m/s. In addition, two regression equations are proposed to determine the Poiseuille number in this study range. Furthermore, the analytical and experimental results are in good agreement.