A novel liquid air energy storage system using a combination of sensible and latent heat storage

This paper proposes a novel stand-alone liquid air energy storage (LAES) system to enhance round-trip efficiency (RTE) using a thermal energy storage system. Thermal energy storage comprises sensible heat storage with quartz and latent heat storage with cryogenic phase change material (PCM) for recycling cold energy from the LAES discharge process. The liquid air in the pressurized tank was released during the discharge cycle and used to store energy using PCM and quartz. The cryogenic phase change material melts at 110 K based on experimental result, making it possible to provide cold heat of fusion 61.62 kJ/kg at a constant temperature for air liquefaction. Thus, proposed system can effectively increase the cold energy recycle. In addition, the two-dimension numerical model allowed us to estimate the outlet temperature of sensible heat store without isothermal assumption by Biot Number. The proposed process is modified from Linde-Hampson, and a sensitivity analysis is performed using ASPEN HYSYS. The analysis shows that the implementation of energy recycling from the compressor and thermal store leads to a high round-trip efficiency (60.6%) higher than base case (34.4%) of LAES system. Therefore, the proposed system is a promising process in terms of simplification and high efficiency, cognizant of the integration of waste heat from industrial plants.

Automated summary

This paper proposes a novel stand-alone liquid air energy storage (LAES) system that enhances round-trip efficiency using a thermal energy storage system. The system effectively increases cold energy recycle by utilizing cryogenic phase change material and quartz for heat storage. A sensitivity analysis shows that the implementation of energy recycling leads to a higher round-trip efficiency compared to the base case of the LAES system.