Experimental study of compressed air energy storage system with thermal energy storage

In this paper, the first public experiment on the CAES (compressed air energy storage) system with TES (thermal energy storage) is presented. A pilot plant using water as thermal energy storage working medium was constructed to investigate the performance of the CAES system with TES. An average round trip energy efficiency of 22.6% was achieved. Detailed analysis for a particular test was performed to study the major factors affecting the system. During the charge process, the consumed compressor electric energy was 1375 kWh with the air pressure inside the storage tank increasing from 3.36 MPa to 9.34 MPa. The total amount of heat absorbed was 565 kWh, while the storage water temperature reached 108.6 °C in the TES system. During the discharge process, the maximum generator power of 430 kW was obtained. The output electric energy was 326 kWh with the air pressure inside the storage tank decreasing from 8.65 MPa to 3.05 MPa. Also, the variation of air temperature along with the air pressure inside the storage tank was discussed during both the charge and discharge process. In this research, efforts are being made to validate the theories in the open literature and extend further practical applications of the CAES system with TES. - Highlights: • Experimental investigation on CAES system with TES was presented. • An average round trip energy efficiency (output electric energy/input electric energy) of 22.6% was achieved. • With water as TES working medium, storage water temperature reached 108.6 °C during charge process. • The maximum generator power of 430 kW was obtained during discharge process.