Adiabatic compressed air energy storage (ACAES) system performance with an application oriented designed axial-flow compressor

ACAES has the potential to perform a key role in the net-zero energy market as an emission-free, medium to long duration, high power and capacity centralised storage solution. ACAES is independent of external heat sources and thus, must rely on the compression heat extracted during charging to re-heat the air prior to expansion. The dependence between compressor outlet and turbine inlet temperatures results in a strong coupling between the charging and discharging processes, requiring the compressors to operate at higher average temperatures. This paper will present the design and performance prediction processes of an application-oriented axial-flow compressor based on the throughflow streamline curvature method for inviscid adiabatic airflow. The designed compressor will then be used in a 300,000 m³ isochoric ACAES system model. The results indicate the designed axial-flow compressor can reach and maintain excellent performance levels throughout the charging process, operating with isentropic efficiency close to 90% as the storage pressure cycles between 5.5 and 7.7 MPa, contributing to a system round trip efficiency of 70%. Further investigation on the compressor operation must follow, but the presented design methodology paves the way to axial-flow compressors being used as highly efficient compression systems, well suited for ACAES applications.