Abstract: Compressed air energy storage systems are an ideal solution to large scale energy storage problem. One of their major advantages is the ease of regulating electricity depending on the demand/load. However, their low thermal efficiency and low energy storage density limit their applications. A solution has been proposed to this major problem by implementing a three-stage compressor with a second recuperator and heat exchanger added after each stage, followed by a three-stage turbine and two reservoirs storage system for trans critical CO2. Furthermore, a three-stage compressor, two stage turbine and two-level storage reservoir system was investigated for supercritical and trans critical air. A thermodynamic and parametric analysis was performed. The study revealed that trans critical CO2 with the respective system has higher round trip efficiency and higher exergy efficiency by ranges of at least 15% compared to all of the existing systems. Also, an additional 28% of mechanical work was recovered in comparison to the unmodified system. Additionally, the study showed that the supercritical air for the corresponding system failed to provide any commercial benefits as its thermodynamic cycle proved unsustainable.

Keywords: Energy Storage, Thermodynamic Analysis, Parametric Analysis, Round Trip Efficiency, Exergy Efficiency, Exergy Destruction Ratio

| DOI: 10.17148/IARJSET.2021.8205