Optimization of air-water microchannel heat exchanger using response surface methodology

Abstract

Multivariate optimization of the air-water heat exchanger with microchannel coil has been presented in this paper. The effects of four geometry parameters, i.e. fin pitch, microchannel flat tube transversal row pitch, number of small channels and partition wall thickness, on heat transfer rate per volume and mass, pressure drops on air and water side, heat transfer efficiency and rate of compactness have been examined using the Response Surface Methodology. Data set, composed of 27 different geometry models, has been prescribed using Box-Behnken design method. Experimentally validated, 3D mathematical model and numerical procedure have been used for numerical simulations. Fluid flow and heat transfer simulations have been performed using CFD solver FLUENT. Numerical results have been employed to calculate the objective function responses. Obtained contour plots of the objective functions have been shown for various setups. According to objective function results, nonlinear regression models (polynomial functions) have been derived and the Genetic Algorithm has been used to obtain optimal setup. The comparison of results has been given, followed by discussion and conclusions.