Dynamic characteristics analysis of the cold energy transfer in the liquid air energy storage system based on different modes of packed bed

Liquid air energy storage (LAES) is a promising large-scale energy storage technology. The packed bed for cold energy storage (CES) has advantages of environmental protection and low cost. Dynamic characteristics in multiple cycles of the packed bed have great influence on the LAES system, but some available researches only focused on the ideal single-stage CES cycle, and the coupling relationship between the packed bed and the LAES system were seldom involved. Therefore, two-stage packed beds considering the intermittent period between the charging and discharging process and the inevitable cold energy loss is studied. The performance of packed beds with different modes during multiple cycles and dynamic response of the LAES system have been analyzed. The results show that with the continuation of cycles, the temperature distribution in the packed bed gradually evolves. The cumulative effect of the axial heat conduction in the intermittent period and the cold energy loss both lead to the decrease in system efficiencies. Considering both the intermittent period and the cold energy loss, the round-trip efficiency of the LAES system is lower than that of the ideal cycle by 16.8% after the quasi steady state.