| Summary: | [Introduction] The demand for energy storage of new power systems (dominated by renewable energy) is increasing. Liquid air energy storage is a new method of physical energy storage with large capacity for long time storage, which has a broad application prospect. the purpose is to explore the thermodynamic principle of liquid air energy storage system and the influence of key parameters on energy storage efficiency. [Method] The thermodynamic models of three basic cycles of liquid air energy storage system: separated cycle, cooling capacity recovery cycle and cooling capacity and heat recovery cycle were established. The influence of key parameters such as cold energy recovery, heat recovery, high pressure and discharge pressure on liquid yield and cycle efficiency was analyzed. [Result] The results show that there is a positive correlation between liquid yield and cycle efficiency. The liquid yield and cycle efficiency of the separated cycle are extremely low. The cooling capacity recovery cycle, using the cooling capacity during temperature rise, significantly improves the liquid yield and cycle efficiency. The cooling capacity and heat recovery cycle further improve the liquid yield and recycling efficiency for the use of heat of compression. The liquid yield and cycle efficiency increase with the increase of cooling capacity recovery, increase with the increase of high pressure, and decrease with the increase of discharge pressure. [Conclusion] Cooling capacity and heat recovery cycle is the optimal scheme of liquid air energy storage. Efficient cooling capacity storage plays an important role in improving cycle efficiency. The utilization of industrial waste heat in the process of liquid-air reheating is helpful to further improve cycle efficiency.
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