Cryogenic supercritical hydrogen, as a physical hydrogen storage method, is used to increase the volume and weight of hydrogen storage density without phase change by means of a combination of cooling and pressurization. In this study, a cryogenic supercritical hydrogen storage system coupled with mixed refrigerant and gas expansion cycle is proposed for the cryogenic supercritical hydrogen cooling thermodynamic process. The cryogenic supercritical hydrogen storage system proposed in this paper can compress and cool hydrogen at ambient temperature and pressure to 70 K and 30 MPa, and the hydrogen storage density at this state point is 72.53 kg/m. Aspen HYSYS software is used to simulate and analyze the system process, and 29 key variables in the system are optimized by genetic algorithm with specific energy consumption (SEC) as the objective function. The system performance is analyzed by varying the expansion refrigeration cycle work gases, and helium, hydrogen and neon are selected for horizontal comparison, and the energy, exergy and heat transfer performance of the three gases are analyzed in detail at the end of the optimization. The results show that neon has the best performance as the expansion cycle working medium, with the SEC of5.87 kWh/kgThe theoretical minimum SEC is 2.92 kWh/kg and the exergy efficiency (EXE) is 49.74 %.

中文翻译：

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制冷剂与气体混合膨胀循环耦合的低温超临界储氢系统设计与优化

低温超临界氢作为一种物理储氢方法，通过冷却和加压相结合的方式，在不发生相变的情况下增加储氢的体积和重量密度。在这项研究中，提出了一种结合混合制冷剂和气体膨胀循环的低温超临界储氢系统，用于低温超临界氢冷却热力过程。本文提出的低温超临界储氢系统可以在常温常压下将氢气压缩冷却至70 K和30 MPa，该状态点的储氢密度为72.53 kg/m3。采用Aspen HYSYS软件对系统过程进行仿真分析，以单位能耗（SEC）为目标函数，采用遗传算法对系统中29个关键变量进行优化。通过改变膨胀制冷循环工作气体来分析系统性能，并选择氦气、氢气和氖气进行横向比较，优化结束时详细分析三种气体的能量、火用和传热性能。结果表明，氖气作为膨胀循环工质性能最佳，SEC为5.87 kWh/kg，理论最小SEC为2.92 kWh/kg，火用效率(EXE)为49.74%。