Transcritical carbon dioxide cycle as a way to improve the efficiency of a Liquid Air Energy Storage system

• Published in: Renewable energy Vol. 196; pp. 1385 - 1391
• Main Authors: Dzido, Aleksandra, Wołowicz, Marcin, Krawczyk, Piotr
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2022
• Subjects: air; air temperature; Carbon dioxide; energy; heat; Hybrid cycle; LAES; Liquid air energy storage; liquids; renewable energy sources; storage technology; Transcritical cycle; LAES; Transcritical cycle; Hybrid cycle; Liquid air energy storage; Carbon dioxide
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2022.07.093

The article deals with the subject of energy storage. This important issue relates to the ongoing transformation toward renewable energy sources. Liquid Air Energy Storage (LAES) is a mechanical energy storage technology that is suitable for large-scale energy storage. The article presents a method to increase the efficiency of LAES by coupling it with the transcritical carbon dioxide cycle. To this end, the paper presents a numerical analysis of two Kapitza LAES systems with the transcritical CO2 cycle: in parallel and subsequent mode. In both cases, maximizing CO2 pressure contributes to greater overall efficiency. It is only profitable to direct residual heat to the CO2 cycle. In contrast, lowering the air temperature prior to expansion in hopes of providing a greater amount of heat to the CO2 cycle actually delivers worse results. Parallel system implementation can add 5–6% to storage efficiency, depending on other factors. In comparison, the subsequent system only adds some 3.5%–5% to storage efficiency.