A cold thermal energy storage based on ASU-LAES system: Energy, exergy, and economic analysis.

This study is dedicated to improving the efficiency of the integrated system of Air Separation Unit (ASU) and Liquid Air Energy Storage (LAES) by introducing two-temperature level Cold Thermal Energy Storage (CTES). In the energy storage stage, the cold thermal energy is released from the CTES, while the ASU load increases, which increases the rate of air liquefaction and realizes the storage of liquid air. In the energy release, the ASU load is reduced, and the stored liquid air is pressurized directly into the column and used for distillation. The enriched cold thermal energy of the product gas is recovered and then stored in the CTES. The CTES of two temperature levels can make the flows in the main exchanger of ASU match well and improve the performance of the system. The presented system shows excellent efficiency, of which the exergy efficiency achieves 79.36 % and the overall efficiency can reach up to 90.66 % in our given conditions. • An ASU-LAES system with cold thermal energy storage (CTES) was proposed. • Two-temperature level thermal energy storage was introduced into the system. • CTES brings in an efficiency increase by matching the flows of the main exchanger. • Isentropic efficiency of compressors/expanders slightly affects the overall efficiency. [ABSTRACT FROM AUTHOR]