Experimental analysis of packed bed cold energy storage in the liquid air energy storage system

Liquid air energy storage (LAES) is a large-scale energy storage technology with extensive demand and promising application prospects. The packed bed for cold energy storage (CES) is widely applied in LAES due to its safety and environmental friendliness. At present, most of the research on CES is theoretical analysis with symmetric cold energy transfer. Actually, the changes of the temperature field result in asymmetrical energy transfer in the energy storage and release processes, but there are few experimental studies on the dynamic characteristics and parameter influence mechanism. Therefore, a platform is established and experiments with different conditions are conducted. The dynamic characteristics of CES and the corresponding performance of LAES are analyzed. The results show that the thermocline develops until outlet temperature changes, leading to a decrease in the LAES efficiency. Under basic conditions, the energy and exergy efficiencies of CES are 90.3 % and 73.3 %. Selecting materials based on physical properties, reducing the flow rate and temperature range of the fluid can improve the packed bed performance. Furthermore, dynamic characteristics of CES gradually weaken until reaching a stable state after multi-cycle, with energy and exergy efficiencies decreasing by 2.5 % and 8.0 %. The decline in the LAES energy efficiency is 4.7 %.