Advanced exergy analysis of a Joule-Brayton pumped thermal electricity storage system with liquid-phase storage. (1st March 2021)

• Record Type: Journal Article
• Authors: Zhao, Yongliang; Liu, Ming; Song, Jian; Wang, Chaoyang; Yan, Junjie; Markides, Christos N.
• Is Part Of: Energy conversion and management. Volume 231(2021)
• Publication Date: 2021-03-01
• Subjects: Advanced exergy analysis -- Joule-Brayton cycle -- Energy storage -- Pumped thermal electricity storage -- PTES -- Sensible heat thermal storage; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2021.113867
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: Advanced exergy analysis of pumped thermal electricity storage systems is proposed. The expander has the maximum exergy destruction rate in the recuperated system. The largest avoidable exergy destruction arises in the recuperator and expander. A quantitative analysis of system performance improvement potential is performed. The modified overall exergetic efficiency increases substantially from 37% to 57%. Abstract: 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.