Design and analysis of flexible integration of solar aided liquid air energy storage system

Abstract

Liquid air energy storage (LAES) system is a promising technology for large-scale energy storage. It is not restricted by the geographical condition and has a high energy storage density. In this paper, on the base of the baseline LAES (BLAES) system, novel solar aided LAES systems with the poly-generation of cold, heat and power are designed to improve the round-trip efficiency (RTE) of the overall system and minimize the number of additional devices. In the best integration case, the solar energy is stored by using the existing air compression heat recovery system, and the air compression heat is effectively utilized. The organic Rankine cycle (ORC) device can be integrated with both the discharging process side and the charging process side to improve the RTE. The results show that the optimized air liquefaction pressure is 160 bar and the air expansion pressure is 120 bar, and the RTE is 53.26% for the BLAES system. For new system, the RTE of the best integration case is 90.49%, 69.90% higher than that of the BLAES system. The RTE of new system with the dual-side integration of ORC is improved by 15.56% compared to that of new system with the ORC single-side integration.