Optimization of a Solvay cycle-based liquid air energy storage system

Abstract

Liquid air energy storage systems (LAES) are being built as an alternative to battery storage to address the intermittent nature of renewable energy sources. In this work, optimization of the LAES operating on a Solvay cycle is performed to determine the best possible operating conditions and round-trip efficiency of the process. The simulation model of the process accounts for the non-linear variation of heat capacity of air, propane, methanol, and thermal oil and the occurrence of internal temperature pinches in the heat exchangers. The optimization results in this work show that the ‘sweet spot’ operating regime corresponds to a charging pressure between 130 and 190 bar and a discharging pressure between 70 and 120 bar, resulting in a round trip efficiency (ηRTE) of more than 60%.