EFFICIENCY ASSESSMENT OF COMPRESSED AIR ENERGY STORAGE SYSTEM COUPLED WITH THERMAL ENERGY STORAGE UNIT: REVIEW

The compressed air energy storage system is one of the emerging storage systems that has recently gained significant attention due to its large storage capacity, eco-friendly, clean technology, and extended life cycle. The present study makes a comprehensive review on the implication of CAES system coupled with TES system. It is noted that when the CAES system is in operation, the cooling system dissipates the majority of the heat produced during compression into the environment, thus reducing its efficiency to 54% or less. Therefore, the post-compression thermal energy can be coupled with an adiabatic thermal energy storage system, which later on can be used to enhance the efficiency of the CAES system. According to its energy and exergy analysis, the adiabatic CAES system can achieve an efficiency of 70% when used in conjunction with a direct-contact type of packed bed (TES) energy system. Past studies demonstrate that the efficiency of A-CAES combined with a heat recuperator increases with more continuous operational cycles and reaches 57% efficiency. In general, it is due to the materials type, geometry, and thermo-physical property, the variation in the thermal efficiency of the TES system is observed that leads to variation in CAES efficiency.