Effect of plate-fin heat exchanger structural parameters on the performance of a cascade refrigeration system

This study investigates the effect of various structural parameters in plate-fin heat exchanger on the performance of a cascade refrigeration system (CRS). Focusing on five key factors—fin thickness, fin type, fin height, porosity, and element axial length—we analyze their contributions to COP , exergy destruction, and entropy production within the CRS. The results reveal that the fin type barely influences the CRS’ performance, the element axial length has the greatest impact, followed by fin height, porosity, and fin thickness, respectively. The COP of the CRS drops by 26.25 % as the element axial length increases from 124 mm to 136 mm, 23.67 % (23.08 %) as the fin height of perforated (straight) fin increases from 6.1 mm to 6.7 mm, and 10.27 % (10.38 %) as the fin thickness of perforated (straight) fin increases from 0.1 mm to 1.3 mm, and the exergy destruction increases by 42.42 %, 37 % (37 %), and 13 % (10.38 %), respectively. The effect of porosity on the CRS’ performance is opposite to that of other parameters. When the element axial length is 124 mm, the fin height is 6.1 mm, and the fin thickness is 0.1 mm, the COP of the CRS reaches the maximum value (0.689). The conclusion can provide data support for the performance optimization of CRS from the structure of the cascade heat exchanger.