Thermodynamic analysis and efficiency assessment of a novel multi-generation liquid air energy storage system

Abstract

In order to get the utmost out of the thermal energy stored in the general liquid air energy storage (LAES) system and improve the cycle efficiency of the energy storage system, this paper proposes a novel multi-generation LAES system. The thermodynamic model and economic model of the novel multi-generation LAES system are constructed. The thermodynamic performance and economy of the novel multi-generation system are analyzed, the cycle efficiency and economic indexes are used as evaluation indicators to compare with the general LAES system. The results show that the novel multi-generation LAES system can provides 325.02 kW of thermal energy, 177.43 kW of cold energy and 3.01 m3/s of fresh air except meets the requirements of 1.5 MW power output. Compared with the general LAES system of 56.48% cycle efficiency, the cycle efficiency of the novel multi-generation LAES system can reach 75.40%. The leveled cost of electricity (LCOE) of the multi-generation LAES system in Beijing is 0.79 ¥/kWh, the rate of return on investment is 20.5%, and the internal rate of return is 27%. The air liquefaction rate reaches 84.52% and the volume of liquid air storage tank is only 121.91 m3. Therefore, the novel multi-generation LAES system with high energy storage density can play a better role in the energy storage scenarios, and not restricted by the geographical environment. In addition, the influence rules of the key parameters, such as unit stages, temperature, pressure and adiabatic efficiency, on the thermodynamic characteristic of the system are also obtained. The novel multi-generation LAES system and related analysis results proposed in this study can provide references for the user side energy storage.