CO2 gas coolers circuitry optimization accounting for fin conduction

In CO₂ transcritical cycles, fin-and-tube coils are commonly used as gas coolers. Studies have shown that for such high temperature heat exchangers, subpar circuitry or refrigerant distribution can lead to high temperature difference between adjacent tubes, leading to significant heat conduction through the fins and capacity degradation. The objective of the study is to investigate the performance improvement obtained from circuitry optimization for CO₂ gas coolers. An Integer Permutation based Genetic Algorithm (IPGA) coupled with a finite volume heat exchanger model capable of accounting for fin conduction and fin-cuts, is used to optimize circuitry for a gas cooler. Case study shows the optimal circuitry has 6.0% capacity increase and 40.0% pressure drop reduction than the conventional counter-flow circuitry with continuous fins. The optimal circuitries can reduce fin conduction effects for continuous fins. In addition to fin-cuts, circuitry optimization is an alternative approach to improve the performance of CO₂ gas coolers.