Flywheel energy storage

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Carl White
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Flywheel energy storage

Postby Carl White » Thu Aug 04, 2016 7:05 pm

http://phys.org/news/2016-08-student-re ... ution.html

"Engineering student designs revolutionary energy storage solution"

How much is there to this? This part confuses me:

The FES retains energy kinetically in a levitated floating mass. The rotor, which can be made from composites such as carbon fibre, is permanently levitated as opposed to electromagnetically


How can it be levitated, except electromagnetically?

Skipjack
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Re: Flywheel energy storage

Postby Skipjack » Thu Aug 04, 2016 8:17 pm

I just want to know what happens when one of these things gets loose.

kunkmiester
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Re: Flywheel energy storage

Postby kunkmiester » Thu Aug 04, 2016 8:29 pm

I'd imagine with permanent magnets.
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krenshala
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Re: Flywheel energy storage

Postby krenshala » Thu Aug 04, 2016 8:55 pm

Skipjack wrote:I just want to know what happens when one of these things gets loose.

Same here. They may be smaller, allowing for better redundancy, but that would only help if non-passive failures don't cascade.

hanelyp
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Re: Flywheel energy storage

Postby hanelyp » Thu Aug 04, 2016 11:01 pm

Levitation of a static object is unstable with just permanent magnets. Levitating a gyroscope on permanent magnets can be stable, baring parasitic forces that can be corrected with a minor force active correction system. Though it becomes a problem if the axis is tilted away from vertical.
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Carl White
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Re: Flywheel energy storage

Postby Carl White » Fri Aug 05, 2016 2:36 am

hanelyp wrote:Levitation of a static object is unstable with just permanent magnets. Levitating a gyroscope on permanent magnets can be stable, baring parasitic forces that can be corrected with a minor force active correction system. Though it becomes a problem if the axis is tilted away from vertical.


Like while the Earth rotates?

paperburn1
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Re: Flywheel energy storage

Postby paperburn1 » Fri Aug 05, 2016 9:38 am

Just spinning it would be almost stable but the real problem (I think) would be when adding or subtracting energy from the system. Any large momentum difference that tends to change the direction of its axis of rotation would result in precession rotation that would be difficult to counter. (adding and subtracting energy from the flywheel)
I am not a nuclear physicist, but play one on the internet.

Tom Ligon
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Re: Flywheel energy storage

Postby Tom Ligon » Fri Aug 05, 2016 11:19 pm

The concept of flywheel storage for the grid has been around for several decades. Some years back there was a consideration of flywheels about 200 m in diameter. One proposal was to make them of bamboo fiber.

The rotating energy in the grid even now is several minutes worth of operation, due to all the dynamos on line, plus some number of synchronous motors doing phase correction.

My best guess is that the axes of the big ones would have to be oriented parallel to Earth's axis to keep them from climbing out of the ground. I'd put them in deep pits.

Levitation by using magnets working against superconducting bearings might work. The levitation works by excluding the magnetic field. This can be made stable ... its the principle behind maglev trains.

I think the technology is workable with conventional bearings and synthetic lubricants.

This project, though, is tiny, the size of a football. I don't see precession as an issue ... just gimbal the whole thing. One of the problems with previous automotive flywheel concepts, which were maybe 1.5 meters in diameter, was that there was no way to rigidly mount a flywheel of that size that would not result in bizarre precession characteristics, like doing a wheelie when you crested a hill.

paperburn1
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Re: Flywheel energy storage

Postby paperburn1 » Sat Aug 06, 2016 12:51 am

Being tiny how much energy does it really store?
And another statement that bothers me "In addition, my FES has a design that can be recycled – which is impossible for batteries." :shock:
I am not a nuclear physicist, but play one on the internet.

kunkmiester
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Re: Flywheel energy storage

Postby kunkmiester » Sat Aug 06, 2016 4:20 am

Don't know much about some of the funky things spinning things do, haven't studied those physics a lot.

I'd bet for a car, you'd carry two, contrarotating, so that the funky stuff cancels out for the most part. You might also run several.

I'm curious now though if liquid nitrogen temp superconductors are at the point a storage torus could be competitive. It's a concept I've heard of for sci-fi, generally using more advanced materials. I have no idea how you calculate that sort of storage potential.
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Carl White
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Re: Flywheel energy storage

Postby Carl White » Sat Aug 06, 2016 11:41 pm

What if you were to put the home-storage sized unit into a big, fat vat of water (large in mass and radius compared to the unit)? Would that suffice to contain the transfer of angular momentum upon failure?

Water is inexpensive in many places. Could use seawater instead of fresh water in places where fresh water is precious.

kunkmiester
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Re: Flywheel energy storage

Postby kunkmiester » Sun Aug 07, 2016 12:25 am

For most installations, a foot or so of concrete on the top of a pit will be sufficient I'd think. Water in contact with the flywheel will screw it up, and putting a tank in a tank is complicated.

Digging and concrete is cheap enough anywhere, so put it in a pit, and you don't have to worry about the sides. Thick enough lid will keep things in.
Evil is evil, no matter how small

paperburn1
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Re: Flywheel energy storage

Postby paperburn1 » Sun Aug 07, 2016 12:09 pm

I don't think containing the explosion/shrapnel is the real concern here. That seems to be fairly straightforward simple engineering and we already have several good ideas on how to contain a failure. I think the real trick and engineering will be the bearings and porting energy into and out of the flywheel itself. Stationary systems will be far far easier than systems that are on the move. Especially if those systems are moving north and south rather than East and West.
I am not a nuclear physicist, but play one on the internet.

KitemanSA
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Re: Flywheel energy storage

Postby KitemanSA » Sun Aug 07, 2016 7:24 pm

Currently, flywheels are only used on the grid for fequency regulation. They are just too expensive for anything else, unless ubidized to a fair-thee-well.

Most modern flywheels are made with fiber reinforced plastic, and when tey fail they usually just puff up into a mess of delaminated fibers.

Skipjack
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Re: Flywheel energy storage

Postby Skipjack » Sun Aug 07, 2016 11:45 pm

JET is using them instead of capacitor banks, from what I understand.
https://www.euro-fusion.org/2010/01/jets-flywheels-2/


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