Energy, exergy, and economic analyses of an innovative energy storage system; liquid air energy storage (LAES) combined with high-temperature thermal energy storage (HTES)

Abstract

Liquid air energy storage is one of the most recent technologies introduced for grid-scale energy storage. As the title implies, this technology offers energy storage through an air liquefaction process. High energy storage density, no geographical limitation, and applicability for large-scale uses are some of the advantages of this technology. To improve the performance and environmental friendliness of the conventional design of this technology, a novel liquid air energy system combined with high-temperature thermal energy storage, thermoelectric generator, and organic Rankine cycle is proposed in the present article. The thermal energy storage unit removes the need for the conventional combustion chamber and thereby reduces greenhouse gas emission. The organic Rankine cycle and the thermoelectric generator recover the generated heat of the system during the charging process to further improve the efficiency of the system. During peak demand periods, around 9.6 MW power and 2.5 kg/s domestic hot water could be generated at round trip energy and exergy efficiencies of 61.13% and 52.84%, improving by 6.59% and 3.28% in comparison to the stand-alone design of this technology. The results indicate that the reference system operates with an air storage energy density and an occupied space energy density of 839 and 104 MJ/m3. The economic analysis represents a payback period of 3.91 years and a net profit of about 18.6 $M during the useful lifetime of the system.