A Solar-Thermal-Assisted Adiabatic Compressed Air Energy Storage System and Its Efficiency Analysis

Adiabatic compressed air energy storage (A-CAES) is an effective balancing technique for the integration of renewables and peak-shaving due to the large capacity, high efficiency, and low carbon use. Increasing the inlet air temperature of turbine and reducing the compressor power consumption are essential to improving the efficiency of A-CAES. This paper proposes a novel solar-thermal-assisted A-CAES system (ST-CAES), which features a higher inhale temperature of the turbine to improve the system efficiency. Solar-thermal energy, as an external thermal source, can alleviate the inadequate temperature of the thermal energy storage (TES), which is constrained by the temperature of the exhaust air of the compressor. Energy and exergy analyses were performed to identify ST-CAES performance, and the influence of key parameters on efficiency were studied. Furthermore, exergy efficiency and the destruction ratio of each component of ST-CAES were investigated. The results demonstrate that electricity storage efficiency, round-trip efficiency, and exergy efficiency can reach 70.2%, 61%, and 50%, respectively. Therefore, the proposed system has promising prospects in cities with abundant solar resources owing to its high efficiency and the ability to jointly supply multiple energy needs.