Design optimization study of cryogenic counter-flow plate fin heat exchangers

Plate-fin heat exchangers are very compact, efficient (>95 %) and can handle multiple streams with low pressure drops. Therefore, these heat exchangers are essentially used in modern large capacity helium liquefier/refrigerator cycles. Cryogenic systems such as helium liquefiers and refrigerators are energy intensive systems and consume large power at room temperature. There is always quest for improved thermodynamic performance and reduction in cool-down time of these systems. Heat exchangers cover major volume and mass in these cryogenic systems. Efficient and optimized design in terms of mass and volume play major role in efficiency improvement and cool-down time of these systems. Present study is aimed to arrive on design configurations which lead to minimum mass and volume of these heat exchangers for the same thermo-hydraulic performance. Method developed here is applied on a heat exchanger which operates in 300-90 K temperature range as a case study. Present study indicates that 44.5 % mass reduction is possible by choosing appropriate fin geometries.