Performance and Complexity Trade Study of Candidate Liquid Air Generation Techniques

This paper presents the results of an alternatives analysis of gas-liquefaction methods used in liquid air energy storage (LAES) systems that incorporates two novel measures of performance (MOP) into the analysis: system complexity score and system density. The cryogenic methods typically considered for air, and used in this trade study, include Linde-Hampson, Claude, Heylandt, and cascade [1]. With these four options of air-liquefaction currently in use for a variety of purposes with ranging scales, there exists no standard selection process for the air-liquefaction method in LAES. This trade study provides fundamental design solutions for given stakeholder requirements, allowing for a pragmatic analysis of integration for future implementation of LAES systems. The intent of these design solutions is to be used in the earliest stage of consideration of a LAES implementation, helping stakeholders quickly narrow the focus of their design engineers to a specific liquefaction process. This will reduce the complexity of integration techniques and processes and streamline LAES into the energy-storage industry. The results of this study showed that with evenly weighted MOP the Heylandt method had the highest final weighted score (0.9), followed by Cascade (0.88), Claude (0.86), and Linde-Hampson (0.67). However, the results showed that the Cascade method was the most frequent design solution (8/11) from 11 variations of MOP weight distributions.