The Effect of Dynamic Cold Storage Packed Bed on Liquid Air Energy Storage in an Experiment Scale

Abstract

Liquid air energy storage (LAES) is one of the most promising large-scale energy storage technologies for the decarburization of networks. When electricity is needed, the liquid air is utilized to generate electricity through expansion, while the cold energy from liquid air evaporation is stored and recovered in the air liquefaction process. The packed bed filled with rocks/pebbles for cold storage is more suitable for real-world application in the near future compared to the fluids for cold storage. A standalone LAES system with packed bed energy storage is proposed in our previous work. However, the utilization of pressurized air for heat transfer fluid in the cold storage packed bed (CSPB) is confusing, and the effect of the CSPB on the system level should be further discussed. To address these issues, the dynamic performance of the CSPB is analyzed with the physical properties of the selected cold storage materials characterized. The system simulation is conducted in an experiment scale with and without considering the exergy loss of the CSPB for comparison. The simulation results show that the proposed LAES system has an ideal round trip efficiency (RTE) of 39.38–52.91%. With the consideration of exergy destruction of the CSPB, the RTE decreases by 19.91%. Furthermore, increasing the cold storage pressure reasonably is beneficial to the exergy efficiency of the CSPB, whether it is non-supercritical (0.1 MPa–3 MPa) or supercritical (4 MPa–9 MPa) air. These findings will give guidance and prediction to the experiments of the LAES and finally promote the development of the industrial application.

Keywords

• liquid air energy storage
• cold storage
• packed bed
• dynamic characteristic