Analysis of Standby Power in an Enclosed High-Speed Flywheel Energy Storage System Using the CFD-ANOVA Approach

During urban driving, a significant amount of energy is lost due to continuous braking, which can be recovered and stored. The flywheel energy storage system (FESS) can efficiently recover and store the vehicle's kinetic energy during deceleration. However, standby losses in FESS, primarily due to aerodynamic drag, can affect its overall efficiency. To address this issue, the flywheel rotor is typically housed in a dedicated housing maintained at a low pressure using a vacuum pump. Standby power is known as the total power used by the auxiliary systems and the power needed to overcome drag and keep the flywheel rotor at a specific state of charge. The Analysis of Variance (ANOVA) technique was combined with the computational fluid dynamics (CFD) technique in this study to determine the optimal flywheel design parameters and investigate their impact on standby power. The study's results demonstrated the optimal combination of the airgap size and the rotor's pressure cavity to achieve the lowest standby power.