Preliminary study on a new cryogenic energy storage system based on natural gas liquefaction

摘要

Aiming at storing the surplus renewable energy resources, a new cryogenic energy storage system (CES) based on natural gas liquefaction is proposed and investigated. The Linde Cycle is adopted in the energy storage section while the Rankine Cycle is employed in the energy recovery section. Based on process-simulation by Aspen HYSYS, the thermodynamic analysis of the CES system under a set of working conditions is carried out. The results show that the energy recovery efficiency of this configuration reaches up to 58.1%, the exergy efficiency of the energy storage section is 81.5% and that of the electricity recovery section is 81.6%. The exergy losses are mainly caused by the irreversibility of compressors, turbines and throttling valve. It is suggested that replacing the throttling valve by expansion devices with higher efficiency, using mixed refrigerants in cold energy recovery section and properly utilizing the heat rejected in hot recovery section may be effective means to improve the system thermal performance.