Modeling, analyses, and assessment of a liquid air energy storage (LAES) system

In this research paper, a comprehensive thermodynamic model of a LAES system is carried out. Exergy analysis as a potential tool to determine the location and magnitude of losses is applied. The proposed system is comprised of two sub-systems, one is used for air liquefaction which is considered as energy storage. This step is called the charging process. The liquid air is then stored in a cryo-tank. The liquid air is then directed to a series of turbo-expanders for the discharge process. For the system simulation, a code is developed which links the Refprop software to Matlab software where thermophysical properties are obtained. In order to have a better insight of the analyses, a parametric study is performed. The effect of several main parameters (i.e., the main pressure entering the cold box, compressor inlet temperature and the first compressor pressure) of the storage cycle on efficiency and cost are investigated. The results indicate that the outlet temperature of the final turbine is limited to the temperature that can enter the evaporator. This constrains limits the inlet temperature to the turbine, which reduces efficiency. In addition, the storage cycle pressure is low. An increase in the main pressure to the cold box can be useful in increasing efficiency. Besides, reducing the inlet temperature to the compressors can increase performance.