Segmented Targeted Design and Multi-Objective Optimization of Printed Circuit Heat Exchanger Used for SCO₂ Recuperator

Printed circuit heat exchangers (PCHE) with high strength and high efficiency have been widely selected for supercritical CO₂ Brayton cycle systems. Precise design and multi-objective optimization of PCHEs are the key to further cost reduction and overall performance improvement. In this paper, a precise design and targeted optimization method of microchannel heat exchangers is proposed. The drastic change of thermophysical properties and the local inhomogeneity of heat transfer during coupled heat transfer on both sides are fully considered and matched with the structural design along the course. Optimization is performed using the NSGA-III algorithm, which couples the working condition parameters with the structural parameters. It is found that the exact method, consisting of a segmented objective non-uniform model, reduces the volume by 9.59% compared to the conventional uniform model. The volume of the optimized PCHE is 0.099 m³. The heat transfer coefficient is significantly improved within the allowable pressure drop. The results of this work can provide important theoretical and technical support for the design, optimization and application of microchannel heat exchangers.