Wireless Electricity

[AhmedEzz]

Can someone tell us about the possible implementation and application of wireless electricity?

I know there is alot of interest in the topic and recently, I read that MIT made a successful experiment of transferring power wirelessly. If we can concentrate the beam of the transmitting element from the generator to be like a laser and send it efficiently to a reciever in a distant location, couldn't that replace transmission lines, at least to islands and remote areas?

I'm open to a scientific discussion but take in mind that i'm in second year undergrad. so I might not get 100% of what you are saying but still I want to make this beneficial and worthy to be posted on PF.

[russ_watters]

Radio is wireless electricity, and microwaves can be made somewhat directional and concentrated, but in that case, you run the risk of killing anything that flies through the beam. Transmission lines are expensive to set up, but they are about 96% efficient iirc.

[AhmedEzz]

well, yeah you might kill anything that goes between the beam but this is rather a minor issue to my eyes than a major one. All antennas are some form of wireless electricity but they are very small in scale and don't meet the application one might anticipate from "wireless electricity".....However, everyone feel free to either continue on with this discussion or answer to the first post of the possibilities of implementation and applications.

[isly ilwott]

Far be it from me to say that it will never happen, but I see little chance of our developing wireless transmission systems to convey megawatts of power as we do now with cables. Not only would it be difficult to transmit, receive and distribute significant amounts of power but it would be difficult to confine the energy to be transmitted from a particular source to a particular sink.

[berkeman]

Here's a recent PF thread with a discussion of the MIT project:

http://www.physicsforums.com/showthread.php?t=237658


.

[AhmedEzz]

100 views and only 4 replies....whatever happened to those who surf PF?

[berkeman]

100 views and only 4 replies....whatever happened to those who surf PF?

I think it's because the previous thread that I posted a link to covered the subject pretty well. That's my guess.

[russ_watters]

That and there is no direction to this thread, no questions to answer, etc.

There are a number of threads on the subject you can peruse for more info, though: http://www.physicsforums.com/search.php?searchid=1221869

[bassplayer142]

In my thoughts this technology should be implemented in smaller household electronics. Charging mp3 players, cell phones, laptops etc... It does use more electricity as it isn't as efficient as a wire.

[AhmedEzz]

Well, any new technology does have its limitations at first but when more promise is being shown more funding kicks in and more research goes on. This is how it works. I think this techonology can have several applications even if we don't imagine those now. For example, how do remote islands in the sea or remote places in the desert recieve electricity? maybe we can devise something that looks like the laser beam, of great efficiency that it becomes cost-effective to build those instead of regular transmission lines. We can even use it as a weapon, for example, remotely electructing someone (a bad guy of course ,hehe ^_^)

[isly ilwott]

I think it's because the previous thread that I posted a link to covered the subject pretty well. That's my guess.

That and there is no direction to this thread, no questions to answer, etc.

There are a number of threads on the subject you can peruse for more info, though: http://www.physicsforums.com/search.php?searchid=1221869I think it's because this idea is much akin to perpetual motion, time machines and beaming systems...they are not worth serious considerations.

Well, any new technology does have its limitations at first but when more promise is being shown more funding kicks in and more research goes on. This is how it works. I think this techonology can have several applications even if we don't imagine those now. For example, how do remote islands in the sea or remote places in the desert recieve electricity? maybe we can devise something that looks like the laser beam, of great efficiency that it becomes cost-effective to build those instead of regular transmission lines. We can even use it as a weapon, for example, remotely electructing someone (a bad guy of course ,hehe ^_^)There are already lasers powerful enough to destroy missiles from great distances...the trouble is, the energy transmitted is absorbed as heat on the receiving end and would then have to be converted to usable electric waveforms.

[berkeman]

I think it's because this idea is much akin to perpetual motion, time machines and beaming systems...they are not worth serious considerations.

The MIT article actually has some semi-useful science in it, but the applications are pretty limited (very short range, low power, etc.).

[isly ilwott]

The MIT article actually has some semi-useful science in it, but the applications are pretty limited (very short range, low power, etc.).Exactly...not worth consideration for transmission of megawatts over appreciable distances.

I have a waterproof, cordless toothbrush that charges via an air gap transformer, but if you lift it an eighth inch, it ceases to charge (at least the "charging" light is extiguished).

[AhmedEzz]

The MIT article actually has some semi-useful science in it, but the applications are pretty limited (very short range, low power, etc.).

And so did every single technology in its infancy, it needs time to develop. If we research and improve current designs so that we could transmit a signal with very high efficiency over a vast distance (we already do that in outer-space applications) but we need to increase the amount of energy transferred. That is the thing..

-We already know transmit and receive signals over vast vast distances like in satelites.
-What is required is to increase the amount of energy to be transferred and still maintain high efficiency.

Ofcourse there is a limit to that but that limit will determine our application. As either to confine the idea to a house or so or to go large-scale and try to reach remote areas in the world.

[bassplayer142]

Is all wireless signals right now just sent out in all directions? If so wouldn't they all be following the inverse cube law demonstrating massive power loss? How well would some parabolic device work?

[mgb_phys]

How well would some parabolic device work?
A focussed beam would still have inverse square power loss. The main problem with a focussed beam is the inefficency in going from electricity->light/microwave->electricity, to be worthwhile you either need a very good reason to use a beam or a lot of incoming power.

In another thread someone proposed powering equipement by sending laser light down an optical fibre to a photocell because they needed to have no electrical connections to the equipement.

[bassplayer142]

In a time where massive amounts of power through hydrogen fusion or other this could be very good at powering satellites across the solar system.