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

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.

Automated summary

The article discusses the use of Liquid Air Energy Storage (LAES) in conjunction with the transcritical carbon dioxide cycle to increase efficiency. The analysis shows that maximizing CO2 pressure and directing residual heat to the CO2 cycle improves storage efficiency, while lowering the air temperature prior to expansion has a negative impact. Implementing a parallel system yields a higher increase in storage efficiency compared to a subsequent system.