Utilizing LNG cold energy in different temperature ranges with distinctive approaches is a promising option to achieve a high thermodynamic efficiency. This paper proposed a novel LNG cold energy cascade utilization (CES-ORC-DC-LNG) system by integrating cryogenic energy storage (CES), organic Rankine cycle (ORC), and direct cooling (DC) to recover LNG cold energy in the low, middle, and high temperature ranges, respectively. The optimal components and their respective fractions of the mixed working fluids in ORCs, and other key parameters were simultaneously determined by a simulation-based optimization approach which was developed in this study. Then, comprehensive energetic and exergetic analyses were conducted to compare the proposed system performance with the system in the literature to highlight the superior thermodynamic performance. The results indicated that the net power output of the CES-ORC-DC-LNG system was 103.30 kW, which was 22.48% higher than the base case. The optimal compositions of the mixed working fluids in ORC-1 (ethane: 23.73%, ethylene: 15.01%, R134a: 20.17%, and R152a: 41.09%) and ORC-2 (ethylene: 60.14%, R134a: 38.73%, R1270: 0.54%, and R134a: 0.59%) were distinctive with the net power output of 13.89 and 14.46 kW, respectively. The round trip efficiency of the proposed system was 141.88% with 19% increment compared with the base case. Furthermore, the exergetic efficiency of the CES-ORC-DC-LNG system was 73.92% which was 5.17% higher than the base case. Thus, the CES-ORC-DC-LNG system is an energy efficiency LNG cold energy cascade utilization system and can be a potential technology for large-scale cryogenic energy storage.

利用独特的方法在不同温度范围内利用LNG冷能是实现高热力学效率的有前途的选择。本文通过结合低温储能（CES），有机朗肯循环（ORC）和直接冷却（DC）来在低温下回收LNG冷能，提出了一种新型的LNG冷能级联利用系统（CES-ORC-DC-LNG）。 ，中和高温范围。本研究中开发的基于仿真的优化方法同时确定了ORC中混合工作流体的最佳成分及其各自的分数以及其他关键参数。然后，进行了全面的能量和能量分析，以将拟议的系统性能与文献中的系统进行比较，以突出优越的热力学性能。结果表明，CES-ORC-DC-LNG系统的净输出功率为103.30 kW，比基本情况高出22.48％。ORC-1（乙烷：23.73％，乙烯：15.01％，R134a：20.17％，和R152a：41.09％）和ORC-2（乙烯：60.14％，R134a：38.73％，R1270）中混合工作流体的最佳组成：0.54％和R134a：0.59％）的独特之处在于其净功率输出分别为13.89 kW和14.46 kW。所提出系统的往返效率为141.88％，与基本情况相比增加了19％。此外，CES-ORC-DC-LNG系统的能源效率为73.92％，比基本情况高5.17％。因此，CES-ORC-DC-LNG系统是一种节能的LNG冷能级联利用系统，可以成为大规模低温储能的潜在技术。