Transcritical Carbon Dioxide Cycle as a Way to Improve the Efficiency of a Liquid Air Energy Storage System
13 Pages Posted: 8 Apr 2022
Abstract
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 CO 2 cycle: in parallel and subsequent mode. In both cases, maximizing CO 2 pressure contributes to greater overall efficiency. It is only profitable to direct residual heat to the CO 2 cycle. In contrast, lowering the air temperature prior to expansion in hopes of providing a greater amount of heat to the CO 2 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% to 5% to storage efficiency.
Keywords: Liquid Air Energy Storage, LAES, carbon dioxide, transcritical cycle, hybrid cycle.
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