Thermodynamic analysis of the concentration-adjustable Linde-Hampson system with a ternary hydrocarbon mixture in the temperature range of -120 ^◦C to -60 ^◦C

In this paper, a concentration-adjustable Linde-Hampson system was proposed, which can actively adjust the component concentrations according to the change of refrigeration conditions. The thermodynamic performance of the proposed and conventional Linde-Hampson systems was evaluated and compared over a refrigeration temperature range of -120 °C to -60 °C. A genetic algorithm in MATLAB, coupled with Aspen HYSYS, was used to optimize the system parameters to maximize the COP. The results show that the proposed system outperforms the conventional system in operating performance. At a refrigeration temperature of -120 °C, the proposed system achieves a COP of 0.31, corresponding to a 78.4% enhancement relative to the conventional system. The core of the performance enhancement lies in the reduction of exergy loss in the recuperative heat exchanger and the throttle valve. Exergo-economic analysis reveals that despite a higher initial investment cost of the proposed system, its total exergy cost is superior when exergy loss cost is considered, with a 33.9% reduction at -120 °C compared with the conventional system. © 2026 Elsevier Ltd and IIR.