This article demonstrates that Cryogenic Energy Storage (CES) systems benefit from a high round-trip efficiency, applying cogeneration concepts to the charging and discharging operating regimes. CES systems are an emerging technology that can mitigate the power grid instabilities in an adverse scenario of high penetration of intermittent sources. We evaluate this novel concept using mass, energy, and exergy balances. We perform numerical simulations and find that the specific liquid yield is 21.4% higher than that reported for other CES systems. The optimization analysis shows that the exergy efficiency is as high as 85.2% whereas the base CES, with no cogeneration, is 50.3%. For the integrated charging and discharging processes, the round-trip efficiency is 41.9%, for the cryogenic tank capacity of 200 t, which is higher than that reported in the previous studies. The optimum values of electrical efficiency and exergy density of the proposed cycle operating in the discharging regime are 81.0% and 123.7 kWh/m³, respectively. In general, the simultaneous operation of the charging and discharging phases in the proposed CES cogeneration system improves the main indexes and indicators. Readers can also benefit from a novel exergy methodology to estimate the efficiency of CES systems.

本文展示了低温储能 (CES) 系统受益于高往返效率，将热电联产概念应用于充电和放电操作制度。CES 系统是一种新兴技术，可以在间歇性电源高渗透率的不利情况下缓解电网的不稳定性。我们使用质量、能量和火用平衡来评估这个新概念。我们进行了数值模拟，发现比液体产量比其他 CES 系统报告的高 21.4%。优化分析表明，火用效率高达 85.2%，而没有热电联产的基础 CES 为 50.3%。对于集成的充放电过程，往返效率为41.9%，对于容量为200 t的低温罐，这高于之前的研究报告。在放电状态下运行的拟议循环的电效率和火用密度的最佳值为 81.0% 和 123.7 kWh/m³、分别。总的来说，拟议的CES热电联产系统中充放电阶段的同时运行提高了主要指标和指标。读者还可以从一种新颖的火用方法中受益，以估计 CES 系统的效率。