Flywheel - Revision history

Farred: correct number of verb

2013-12-12T14:09:51Z

correct number of verb

Farred: adding category

2011-10-13T22:22:52Z

adding category

Farred: /* Magnetically Supported Flywheel Hoops */ addition

2011-10-06T22:04:39Z

Magnetically Supported Flywheel Hoops: addition

75.73.161.116: /* Magnetically Supported Flywheel Hoops */ addition

2010-06-21T22:12:58Z

Magnetically Supported Flywheel Hoops: addition

Farred: magnetically supported flywheel hoops

2010-03-06T00:25:36Z

magnetically supported flywheel hoops

131.252.241.134: In space, should use a pair of flywheels in order to conserve angular momentum.

2009-03-04T03:34:07Z

In space, should use a pair of flywheels in order to conserve angular momentum.

Anders Feder at 21:29, 19 February 2009

2009-02-19T21:29:36Z

Anders Feder: New page: 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 ...

2009-02-19T18:36:58Z

New page: 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 ...

New page

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 the rover, flywheels can stabilize motion due to the gyroscopic effect.

Current best theoretical energy densities of flywheel batteries are around 200 Wh/kg.

← Older revision		Revision as of 22:22, 13 October 2011
Line 13:		Line 13:
	== Magnetically Supported Flywheel Hoops ==		== Magnetically Supported Flywheel Hoops ==
	The best theoretical energy density calculation for a flywheel assumes that the flywheel is prevented from flying apart by its own structural strength. So larger flywheels with lower centrifugal force for the same rim speed get no advantage because the larger wheel has more mass to support. However a flywheel need not be limited to its own structural strength to keep from flying apart. If a flywheel consists only of the rim and the radius is ten kilometers, then 1005 meters per second squared acceleration at the rim would be generated by a rotation rim velocity of 3170 meters per second. This 102.6 g centrifugal force could be countered completely by magnetic force holding the iron rim in place with no hoop stress and no requirement for structural strength to resist the hoop stress. The structural strength of Luna itself would be used to hold the flywheel together with the force being transferred to the flywheel magnetically just as force to hold a magnetically supported rail road train above the tracks is transferred magnetically. This would result in a flywheel with 5.02 * 10<sup>6</sup> watt seconds per kilogram or 1400 watt hours per kilogram. This would not be the kind of flywheel that one would use to power a vehicle rolling around Luna. It would be used for stationary facility power storage. For higher power densities people would design larger diameter flywheel rims. There is the added complication of designing an electric motor generator to ride on the magnetically supported iron rim, but this should only reduce the power density by a small fraction. This technology could be used on earth with an evacuated donut shaped tube to hold the flywheel. A one meter diameter evacuated tube would be curved to form a ten kilometer radius donut. The hoop rotating at 3170 meters per second inside, riding on magnetic levitation, would provide reasonable power storage on earth. The proven technology would later be used on Luna with no need for the vacuum chamber.		The best theoretical energy density calculation for a flywheel assumes that the flywheel is prevented from flying apart by its own structural strength. So larger flywheels with lower centrifugal force for the same rim speed get no advantage because the larger wheel has more mass to support. However a flywheel need not be limited to its own structural strength to keep from flying apart. If a flywheel consists only of the rim and the radius is ten kilometers, then 1005 meters per second squared acceleration at the rim would be generated by a rotation rim velocity of 3170 meters per second. This 102.6 g centrifugal force could be countered completely by magnetic force holding the iron rim in place with no hoop stress and no requirement for structural strength to resist the hoop stress. The structural strength of Luna itself would be used to hold the flywheel together with the force being transferred to the flywheel magnetically just as force to hold a magnetically supported rail road train above the tracks is transferred magnetically. This would result in a flywheel with 5.02 * 10<sup>6</sup> watt seconds per kilogram or 1400 watt hours per kilogram. This would not be the kind of flywheel that one would use to power a vehicle rolling around Luna. It would be used for stationary facility power storage. For higher power densities people would design larger diameter flywheel rims. There is the added complication of designing an electric motor generator to ride on the magnetically supported iron rim, but this should only reduce the power density by a small fraction. This technology could be used on earth with an evacuated donut shaped tube to hold the flywheel. A one meter diameter evacuated tube would be curved to form a ten kilometer radius donut. The hoop rotating at 3170 meters per second inside, riding on magnetic levitation, would provide reasonable power storage on earth. The proven technology would later be used on Luna with no need for the vacuum chamber.
		+
		+	[[Category:Power Supply]]

← Older revision		Revision as of 22:04, 6 October 2011
Line 12:		Line 12:

	== Magnetically Supported Flywheel Hoops ==		== Magnetically Supported Flywheel Hoops ==
−	The best theoretical energy density calculation for a flywheel assumes that the flywheel is prevented from flying apart by its own structural strength. So larger flywheels with lower centrifugal force for the same rim speed get no advantage because the larger wheel has more mass to support. However a flywheel need not be limited to its own structural strength to keep from flying apart. If a flywheel consists only of the rim and the radius is ten kilometers, then 1005 meters per second squared acceleration at the rim would be generated by a rotation rim velocity of 3170 meters per second. This 102.6 g centrifugal force could be countered completely by magnetic force holding the iron rim in place with no hoop stress and no requirement for structural strength to resist the hoop stress. This would result in a flywheel with 5.02 * 10<sup>6</sup> watt seconds per kilogram or 1400 watt hours per kilogram. This would not be the kind of flywheel that one would use to power a vehicle rolling around Luna. It would be used for stationary facility power storage. For higher power densities people would design larger diameter flywheel rims. There is the added complication of designing an electric motor generator to ride on the magnetically supported iron rim, but this should only reduce the power density by a small fraction. This technology could be used on earth with an evacuated donut shaped tube to hold the flywheel. A one meter diameter evacuated tube would be curved to form a ten kilometer radius donut. The hoop rotating at 3170 meters per second inside, riding on magnetic levitation, would provide reasonable power storage on earth. The proven technology would later be used on Luna with no need for the vacuum chamber.	+	The best theoretical energy density calculation for a flywheel assumes that the flywheel is prevented from flying apart by its own structural strength. So larger flywheels with lower centrifugal force for the same rim speed get no advantage because the larger wheel has more mass to support. However a flywheel need not be limited to its own structural strength to keep from flying apart. If a flywheel consists only of the rim and the radius is ten kilometers, then 1005 meters per second squared acceleration at the rim would be generated by a rotation rim velocity of 3170 meters per second. This 102.6 g centrifugal force could be countered completely by magnetic force holding the iron rim in place with no hoop stress and no requirement for structural strength to resist the hoop stress. The structural strength of Luna itself would be used to hold the flywheel together with the force being transferred to the flywheel magnetically just as force to hold a magnetically supported rail road train above the tracks is transferred magnetically. This would result in a flywheel with 5.02 * 10<sup>6</sup> watt seconds per kilogram or 1400 watt hours per kilogram. This would not be the kind of flywheel that one would use to power a vehicle rolling around Luna. It would be used for stationary facility power storage. For higher power densities people would design larger diameter flywheel rims. There is the added complication of designing an electric motor generator to ride on the magnetically supported iron rim, but this should only reduce the power density by a small fraction. This technology could be used on earth with an evacuated donut shaped tube to hold the flywheel. A one meter diameter evacuated tube would be curved to form a ten kilometer radius donut. The hoop rotating at 3170 meters per second inside, riding on magnetic levitation, would provide reasonable power storage on earth. The proven technology would later be used on Luna with no need for the vacuum chamber.

← Older revision		Revision as of 22:12, 21 June 2010
Line 12:		Line 12:

	== Magnetically Supported Flywheel Hoops ==		== Magnetically Supported Flywheel Hoops ==
−	The best theoretical energy density calculation for a flywheel assumes that the flywheel is prevented from flying apart by its own structural strength. So larger flywheels with lower centrifugal force for the same rim speed get no advantage because the larger wheel has more mass to support. However a flywheel need not be limited to its own structural strength to keep from flying apart. If a flywheel consists only of the rim and the radius is ten kilometers, then 1005 meters per second squared acceleration at the rim would be generated by a rotation rim velocity of 3170 meters per second. This 102.6 g centrifugal force could be countered completely by magnetic force holding the iron rim in place with no hoop stress and no requirement for structural strength to resist the hoop stress. This would result in a flywheel with 5.02 * 10<sup>6</sup> watt seconds per kilogram or 1400 watt hours per kilogram. This would not be the kind of flywheel that one would use to power a vehicle rolling around Luna. It would be used for stationary facility power storage. For higher power densities people would design larger diameter flywheel rims. There is the added complication of designing an electric motor generator to ride on the magnetically supported iron rim, but this should only reduce the power density by a small fraction. This technology could be used on earth in an evacuated ten kilometer radius ~~tube~~, ~~providing~~ reasonable power storage. ~~This~~ would ~~also prove some technology needed~~ for ~~a lunar colony~~.	+	The best theoretical energy density calculation for a flywheel assumes that the flywheel is prevented from flying apart by its own structural strength. So larger flywheels with lower centrifugal force for the same rim speed get no advantage because the larger wheel has more mass to support. However a flywheel need not be limited to its own structural strength to keep from flying apart. If a flywheel consists only of the rim and the radius is ten kilometers, then 1005 meters per second squared acceleration at the rim would be generated by a rotation rim velocity of 3170 meters per second. This 102.6 g centrifugal force could be countered completely by magnetic force holding the iron rim in place with no hoop stress and no requirement for structural strength to resist the hoop stress. This would result in a flywheel with 5.02 * 10<sup>6</sup> watt seconds per kilogram or 1400 watt hours per kilogram. This would not be the kind of flywheel that one would use to power a vehicle rolling around Luna. It would be used for stationary facility power storage. For higher power densities people would design larger diameter flywheel rims. There is the added complication of designing an electric motor generator to ride on the magnetically supported iron rim, but this should only reduce the power density by a small fraction. This technology could be used on earth with an evacuated donut shaped tube to hold the flywheel. A one meter diameter evacuated tube would be curved to form a ten kilometer radius donut. The hoop rotating at 3170 meters per second inside, riding on magnetic levitation, would provide reasonable power storage on earth. The proven technology would later be used on Luna with no need for the vacuum chamber.

← Older revision		Revision as of 00:25, 6 March 2010
Line 10:		Line 10:

	Current best theoretical energy densities of flywheel batteries are around 200 Wh/kg.		Current best theoretical energy densities of flywheel batteries are around 200 Wh/kg.
		+
		+	== Magnetically Supported Flywheel Hoops ==
		+	The best theoretical energy density calculation for a flywheel assumes that the flywheel is prevented from flying apart by its own structural strength. So larger flywheels with lower centrifugal force for the same rim speed get no advantage because the larger wheel has more mass to support. However a flywheel need not be limited to its own structural strength to keep from flying apart. If a flywheel consists only of the rim and the radius is ten kilometers, then 1005 meters per second squared acceleration at the rim would be generated by a rotation rim velocity of 3170 meters per second. This 102.6 g centrifugal force could be countered completely by magnetic force holding the iron rim in place with no hoop stress and no requirement for structural strength to resist the hoop stress. This would result in a flywheel with 5.02 * 10<sup>6</sup> watt seconds per kilogram or 1400 watt hours per kilogram. This would not be the kind of flywheel that one would use to power a vehicle rolling around Luna. It would be used for stationary facility power storage. For higher power densities people would design larger diameter flywheel rims. There is the added complication of designing an electric motor generator to ride on the magnetically supported iron rim, but this should only reduce the power density by a small fraction. This technology could be used on earth in an evacuated ten kilometer radius tube, providing reasonable power storage. This would also prove some technology needed for a lunar colony.

← Older revision		Revision as of 03:34, 4 March 2009
Line 1:		Line 1:
−	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~~.	+	Flywheel batteries work by accelerating a pair of rotors (flywheels) to a very high speed and maintaining the energy in the system as rotational energy. The energy is converted back by slowing down the flywheels.

	The space environment has a number of advantages for flywheel energy storage:		The space environment has a number of advantages for flywheel energy storage:

@@ Line 5: / Line 5: @@
 * 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.
+* Due to the absence of living beings, minimal safety precautions, in case the spinning flywheel 'explodes', have 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.