Harvesting energy from the earth rotation

[johnmn3]

Here's a businessweek article on these guys in 1995: http://www.businessweek.com/stories/1995-08-27/as-the-world-turns-free-energy

 

[johnmn3]

According to this research, graphene flakes can spin up to 60,000,000 rpm. http://www.newscientist.com/article/dn19514-levitating-graphene-is-fastestspinning-object-ever.html

Couple that with research showing that strained graphene can generate pseudo-magnetic fields in excess of 300 teslas: http://newscenter.lbl.gov/news-releases/2010/07/29/graphene-under-strain/

Graphene sounds like a good material for this.

A nanoscale gyro might have more optimal friction characteristics as well: http://www.nepachemistry.com/2011/01/macroscopic-and-microscopic-molecular.html

 

[LURCH]

Supposing we had a gyroscope with 100% mechanical efficiency -- say it is in a vacuum chamber, suspended in place by some frame of superconductors.

Also suppose this gyroscope has magnets on it, facing outward from the walls of the spinning surface (where the white paint on a car's white-wall tires would be), such that we can externally apply force against the axis of the gyroscope's spin, without causing friction.

Now, it is not a stretch to imagine how, as the Earth rotates, the gyroscope's magnets will apply force against a set of magnets connected to a motor that is planted on the earth.

I guess the question is, does applying force against the gyroscope's axis of rotation cause the rotation to slow down? Even if the spin is 100% mechanically efficient?

Yes, the magnetic field acting against the gyro will impart some drag. Eventually, this drag will slow the gyro's rotation to a stop (relative to the magnets). The amount of energy that can be extracted during this process will be slightly less than the amount it took to get the gyro spinning in the first place.

 

[johnmn3]

People keep thinking this a free energy scheme. It is not.

Just imagine a bike wheel spinning on a string. Now add another small wheel to the rim (perpendicular to the big wheel). Spin the big wheel really fast. Now spin the small wheel really fast. The small wheel will start to slow down the spin of the big wheel -- their angular momentums are fighting each other. The small wheel is taking energy away from the big wheel.

Now put the small wheel on a gimbal and now it can maintain the small wheels orientation freely, letting the big wheel spin on its own accord. Now the small wheel is not taking energy away from the big wheel.

Now put a gear box on the small wheel's gimbal and let the large wheel compete with the small wheel with half the force it normally would exhibit without the gimbal. Now the small wheel is being forced to spin at half the speed of the big wheel. This takes energy away from the big wheel but feeds that energy into the gear box.

Does that make sense?

 

[Simon Bridge]

Thanks. Pleasure to be here. The frame would be secured to an object on the earth. It would have a gear system that puts pressure on the gyro as it tries to turn. Would the rotation slow down if the gyro were pushed against its spinning axis?

Well ... yes.
The problem with these sorts of projects is getting the thing harvesting the energy to take it from the Earth and not the Gyro. In practice you end up only getting the energy out that you put in when you set the gyro spinning.

Here it is the frame turning wrt the gyro axis that is the motion you want to get energy from.
You had to put energy in by spinning the gyro in the first place - in practice you'll have to keep boosting this but work out the plausibility by assuming it does not run down by itself.

The next bit will be where you put the magnet and where the generator coils - don't get bogged down in the details of what kind of magnets and conductors you will use: that's for later. You need them placed to harvest the Earth's rotational energy ... eg. if you tried it with a mechanical gear-chain driving an electric generator, you'd have trouble placing the generator so it is not also rotating with the earth.

People keep thinking this a free energy scheme. It is not.

No - it is just massively impractical though well tried.
Usually people forget about where the generator has to go, or they fail to account for the energy used spinning up the gyro in the first place.

Also have a look at this demo:
http://www.lhup.edu/~dsimanek/museum/advanced.htm
... you seem to have that setup ... generator attached to support-frame, magnet on the gyro-frame.
The PHYS-L discussion in question is here, and still available.
Of particular note is this observation: a steel disk 1m thick and 3m in radius spinning at 10 cycles/s (!?). Would have a max (ideal) power output of ~100mW and cost you some 2GJ to spin it up.

You can have a go tweaking the figures:

$$P_{max} = \tau_g \omega_s = \frac{\omega_s}{2}\frac{dL_g}{dt} = \frac{1}{2}\omega_e L_g = \frac{1}{4}I_g\omega_g\omega_e^2$$ ... where:
$\tau_g$ is the torque on the gyro (under load),
$\omega_s$ is the angular velocity of the shaft wrt Earth,
$L_g$ is the angular momentum of the gyro,
$\omega_e$ is the angular velocity of the Earth, and
$\omega_g$ is the angular velocity of the gyro about it's spin axis.

 

[mfb]

Just imagine a bike wheel spinning on a string. Now add another small wheel to the rim (perpendicular to the big wheel). Spin the big wheel really fast. Now spin the small wheel really fast. The small wheel will start to slow down the spin of the big wheel -- their angular momentums are fighting each other. The small wheel is taking energy away from the big wheel.

To get any increase of the speed of the small wheel, you need external interaction (friction or whatever) - something you do not have in the earth+gyro system. You can spin up the big wheel and slow the smaller one, but that is not useful.


You can design anything you want, it does not matter. Just with energy and momentum conservation, it is possible to show that your setup does not work in an isolated system. To make it work, you need at least one of those 4:
- an external interaction: This can be the moon, or launching things to space, or whatever
- a violation of energy conservation
- a violation of linear momentum conservation
- a violation of angular momentum conservation

It can be shown (this is a mathematical proof) that energy conservation follows from time-independent physical laws, and momentum conservation from space- and orientation independence of the physical laws. Those can be studied on a very fundamental level. If you do not find any violation there (certainly worth a Nobel prize), your concept cannot work unless you go to space.

 

[Simon Bridge]

To get any increase of the speed of the small wheel, you need external interaction (friction or whatever) - something you do not have in the earth+gyro system. You can spin up the big wheel and slow the smaller one, but that is not useful.

The big-wheel+small-wheel thing puzzled me since it has little to do with the setup being considered with the variations on the gyrogenerator.

The equivalent with the big wheel being the Earth would be just to run the small wheel along the ground... if you could get into a position where the Earth is turning under you then you could just hold a small wheel to the Earth to generate power: the trick is getting in that position to start with.

However - I thought that the generator being considered was like the one in the link I supplied (the apparent 1/day precession of a gyroscope being used to generate power). This one does not violate any conservation laws that I know of - it is just very very impractical.

People get excited over it for much the same reasons they go starry eyed of perpetual motion or over-unity machines: important stuff got left out. Lots of attention gets lavished on supermagnets and conductors and high-tech materials, just like with pmm, then the proponent points out that this is not a "free energy" machine... yet the basics of how much energy is available vs invested gets overlooked.

 

[mfb]

if you could get into a position where the Earth is turning under you then you could just hold a small wheel to the Earth to generate power: the trick is getting in that position to start with.

To get in such a position and keep it (even with the force required to accelerate the small wheel), you need some external anchor.

it is just very very impractical.

It is not just impractical, it is a pure waste of useful power. You can simply use the flywheel in the conventional way as energy storage and get the same result, but with a better efficiency.

 

[Buckleymanor]

To get in such a position and keep it (even with the force required to accelerate the small wheel), you need some external anchor.

Why do you need an external anchor.Is it not the proposal of using a gyro to be able to use it as an anchor.The giro is set spinning say on it's side at the north pole, if it's left spinning for a day it will appear to make one complete rotation.It is not rotateing it's just obeying Newton's laws in as much that it wan't to move in one direction once the giro is spinning.
I'ts the Earth that is rotateing beneath it.
The giro stays put like an anchor.

 

[willem2]

Why do you need an external anchor.Is it not the proposal of using a gyro to be able to use it as an anchor.The giro is set spinning say on it's side at the north pole, if it's left spinning for a day it will appear to make one complete rotation.It is not rotateing it's just obeying Newton's laws in as much that it wan't to move in one direction once the giro is spinning.
I'ts the Earth that is rotateing beneath it.
The giro stays put like an anchor.

This thread has really been dead since post #7.
If you wan't to get energy out of the Earth's rotation you have to slow it down.
If you want to slow down the earth, you have to give some of its angular momentum to something else, which in this case can only be the anchor. For this reason the anchor will have to start spinnng with the earth.

 

[mfb]

Why do you need an external anchor.

Please read the quoted text in my post, my comment was related to a different setup.

This thread has really been dead since post #7.

So true...

 

[D H]

This thread has really been dead since post #7.

Pretty close to that. (But you did miss the option of transferring angular momentum on objects sent from the Earth.)

This thread is closed.

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