Pumped thermal electricity storage is a thermo-mechanical energy storage technology that has emerged as a promising option for large-scale (grid) storage because of its lack of geographical restrictions and relatively low capital costs. This paper focuses on a 10 MW Joule-Brayton pumped thermal electricity storage system with liquid thermal stores and performs detailed conventional and advanced exergy analyses of this system. Results of the conventional exergy analysis on the recuperated system indicate that the expander during discharge is associated with the maximum exergy destruction rate (13%). The advanced exergy analysis further reveals that, amongst the system components studied, the cold heat exchanger during discharge is associated with the highest share (95%) of the avoidable exergy destruction rate, while during charge the same component is associated with the highest share (64%) of the endogenous exergy destruction rate. Thus, the cold heat exchanger offers the largest potential for improvement in the overall system exergetic efficiency. A quantitative analysis of the overall system performance improvement potential of the recuperated system demonstrates that increasing the isentropic efficiency of the compressor and turbine from 85% to 95% significantly increases the modified overall exergetic efficiency from 37% to 57%. Similarly, by increasing the effectiveness and decreasing the pressure loss factor of all heat exchangers, from 0.90 to 0.98 and from 2.5% to 0.5% respectively, the modified overall exergetic efficiency increases from 34% to 54%. The results of exergy analyses provide novel insight into the innovation, research and development of pumped thermal electricity storage technology.

抽水蓄热是一种热机械能存储技术，由于缺乏地域限制和相对较低的资金成本，因此已成为大规模（网格）存储的有前途的选择。本文着重于具有液体蓄热器的10兆瓦焦耳-布雷顿抽水蓄热系统，并对该系统进行详细的常规和高级火用分析。换热系统常规火用分析的结果表明，膨胀机在排放过程中与最大火用破坏率（13％）有关。先进的火用分析进一步表明，在所研究的系统组件中，排放期间的冷热交换器与可避免的火用破坏率的最高份额（95％）相关，而在充电过程中，同一成分与内源性火用破坏率的最高份额（64％）相关。因此，冷热交换器为改善整个系统的能源效率提供了最大的潜力。对同流回热系统整体系统性能改善潜力的定量分析表明，将压缩机和涡轮的等熵效率从85％提高到95％，可以显着提高改进后的总能效从37％提高到57％。同样，通过提高所有换热器的效率并降低其压力损失系数（分别从0.90至0.98和2.5％至0.5％），改进的总能效从34％增加至54％。火用分析的结果为创新提供了新颖的见解，