New technique harvests electricity from nature's motions

[tomtt]

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Washington, October 31: Duke University engineers have developed a novel approach that they believe can more efficiently harvest electricity from the everyday motions of the natural world.

Energy harvesting is the process of converting one form of energy, such as motion, into another form of energy, in this case electricity.

Strategies range from the development of massive wind farms to produce large amounts of electricity to using the vibrations of walking to power small electronic devices.

Although motion is an abundant source of energy, only limited success has been achieved because the devices used only perform well over a narrow band of frequencies.

"Nature doesn't work in a single frequency, so we wanted to come up with a device that would work over a broad range of frequencies," said Samuel Stanton, graduate student in Duke's Pratt School of Engineering.

"By using magnets to 'tune' the bandwidth of the experimental device, we were able verify in the lab that this new non-linear approach can outperform conventional linear devices," he added.

Although the device they constructed looks deceptively simple, it was able to prove the team's theories on a small scale.

It is basically a small cantilever, several inches long and a quarter inch wide, with an end magnet that interacts with nearby magnets.

The cantilever base itself is made of a piezoelectric material, which has the unique property of releasing electrical voltage when it is strained.

The key to the new approach involved placing moveable magnets of opposing poles on either side of the magnet at the end of the cantilever arm.

By changing the distance of the moveable magnets, the researchers were able to "tune" the interactions of the system with its environment, and thus produce electricity over a broader spectrum of frequencies.

"These results suggest to us that this non-linear approach could harvest more of the frequencies from the same ambient vibrations," said Brian Mann, assistant professor of mechanical engineering and materials sciences, Duke's Pratt School of Engineering.

"More importantly, being able to capture more of the bandwidth makes it more likely that these types of devices could someday rival batteries as a portable power source," he added.


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[c2cthomas]

If a way can be devised to connect the "small cantilever" to our politicians mouths an inexhaustible source of electrical power could result. Plus - if we add a 33 1/3 rpm platter we might be able to listen to some nice music if we can put mute button on said politicians.

Nah, mute button + politician = never happen......... Attaching it to beds in the local red light district could be productive tho

[Enzo]

I can see it now, giant 300 foot tall wind machines with enormous cantileverd magnet structures. What works well at 10" doesn't always scale up so well.

or are we talking about small scale things like wristwatch power supply?

[c2cthomas]

Perhaps something that is made to look like a tree - could be a fir tree - that used the branches as the cantilever(s) could be devised. 360 degree access to wind without having to rotate the base into the wind - and could be made to look much more attractive than a 300 foot (100 meter) tall windmill (which have blades that wound and kill birds). But then there are also proposals to trap the methane gas produced by livestock and burn it as a gas to power turbines with.

I still refer to the politicians - now we can hook-up the cantilever to their mouths and trap the gas and hot air they produce in massive amounts and produce enough energy to meet our needs for years to come.

Nano machines could be the other end of the spectrum to look at - or we could simply give some young kids some erector sets and let 'em have at it.

[ashok]

Nicola Tesla supposedly built two tall insulated posts at his house and it was rigged up with an apparatus that collected electricity generated by it. Was supposedly about 80% efficient at night as compared to daytime performance. It collected energy present in the atmosphere which doesn't die down completely at night.
It harvested energy that comes from the Sun and is captured by the Earth's magnetic field. So it's present 24 hours a day.
They say it was destroyed by some 'interested people'. What was it and how did it really work ?

Seen the free wheeling machine that uses lead(?) balls to help it keep rotating once started and then continue to do so when connected to a small motor and a large generator ( 2.5KW) ? You'll find it on You Tube. Australian again !

[star882]

In theory, it is also possible to generate electricity from radio waves.
Nikola Tesla Page, Tesla's power receiver

[wg_ski]

Originally Posted by star882

In theory, it is also possible to generate electricity from radio waves.

Assuming radio waves were "free" - and you do have to be in a position to capture enough of them. I'm sure you could capture significant energy off of Channel 8's tower if you wanted to, but if it messes up their radiation pattern and transmit range they may get upset about it. Sort of like setting up a big coil of wire under a high tension line - it does sort-of work, but they will eventually find where that load on their system is.

[Magura]

Originally Posted by star882

In theory, it is also possible to generate electricity from radio waves.
Nikola Tesla Page, Tesla's power receiver

It sure is. I have seen a small incandescent lamp work like that next to a big TV tower, but as stated above, I guess it's not gonna fly.


Magura