Flywheel
Revision as of 14:29, 19 February 2009 by Anders Feder (talk | contribs)
Flywheel batteries work by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. The energy is converted back by slowing down the flywheel.
The space environment has a number of advantages for flywheel energy storage:
- The natural vacuum eliminates energy losses due to atmospheric drag.
- Cryogenic temperatures of space enable superconductor magnetic bearings that minimize friction in the system, without further refrigeration.
- Energy losses due to friction, hysteresis etc. can be utilized to heat the spacecraft.
- Due to the absence of living beings, minimal safety precautions, in case the spinning flywheel 'explodes', has to be made.
- Because of their angular momentum, flywheels can act as reaction wheels for attitude control as well, even while storing energy.
Furthermore, in vehicles, such as a lunar rover, flywheels can stabilize motion due to the gyroscopic effect.
Current best theoretical energy densities of flywheel batteries are around 200 Wh/kg.
