Flywheel energy storage (Energy density)
Description
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheel energy storage works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy. When energy is extracted from the system, the flywheel’s rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the flywheel. A typical system consists of a rotor suspended by bearings inside a vacuum chamber to reduce friction, connected to a combination electric motor and electric generator. The maximum energy density of a flywheel single-material, isotropic rotor is mainly dependent on the rotor’s geometry and the properties of the material being used.
Related formulasVariables
E | The kinetic energy of the rotor (J) |
m | The rotor's mass (kg) |
K | The rotor's geometric shape factor (dimensionless) |
σ | The tensile strength of the material (Pa) |
ρ | The material's density (kg/m3) |