Physics Promises Wireless Power

[theem 0]

Physics promises wireless power


Plugs and wires could soon become a thing of the past
The tangle of cables and plugs needed to recharge today's electronic gadgets could soon be a thing of the past.

US researchers have outlined a relatively simple system that could deliver power to devices such as laptop computers or MP3 players without wires.

The concept exploits century-old physics and could work over distances of many metres, the researchers said.

Although the team has not built and tested a system, computer models and mathematics suggest it will work.

"There are so many autonomous devices such as cell phones and laptops that have emerged in the last few years," said Assistant Professor Marin Soljacic from the Massachusetts Institute of Technology and one of the researchers behind the work.

"We started thinking, 'it would be really convenient if you didn't have to recharge these things'.

"And because we're physicists we asked, 'what kind of physical phenomenon can we use to do this wireless energy transfer?'."


How wireless energy could work
The answer the team came up with was "resonance", a phenomenon that causes an object to vibrate when energy of a certain frequency is applied.


This would work in a room let's say but you could adapt it to work in a factory

Marin Soljacic

"When you have two resonant objects of the same frequency they tend to couple very strongly," Professor Soljacic told the BBC News website.

Resonance can be seen in musical instruments for example.

"When you play a tune on one, then another instrument with the same acoustic resonance will pick up that tune, it will visibly vibrate," he said.

Instead of using acoustic vibrations, the team's system exploits the resonance of electromagnetic waves. Electromagnetic radiation includes radio waves, infrared and X-rays.

Typically, systems that use electromagnetic radiation, such as radio antennas, are not suitable for the efficient transfer of energy because they scatter energy in all directions, wasting large amounts of it into free space.

To overcome this problem, the team investigated a special class of "non-radiative" objects with so-called "long-lived resonances".

When energy is applied to these objects it remains bound to them, rather than escaping to space. "Tails" of energy, which can be many metres long, flicker over the surface.

"If you bring another resonant object with the same frequency close enough to these tails then it turns out that the energy can tunnel from one object to another," said Professor Soljacic.


Wireless energy transfer has been thought about for centuries

Hence, a simple copper antenna designed to have long-lived resonance could transfer energy to a laptop with its own antenna resonating at the same frequency. The computer would be truly wireless.

Any energy not diverted into a gadget or appliance is simply reabsorbed.

The systems that the team have described would be able to transfer energy over three to five metres.

"This would work in a room let's say but you could adapt it to work in a factory," he said.

"You could also scale it down to the microscopic or nanoscopic world."

Old technology

The team from MIT is not the first group to suggest wireless energy transfer.

Nineteenth-century physicist and engineer Nikola Tesla experimented with long-range wireless energy transfer, but his most ambitious attempt - the 29m high aerial known as Wardenclyffe Tower, in New York - failed when he ran out of money.




Wireless power for gadgets

Others have worked on highly directional mechanisms of energy transfer such as lasers.

However, these require an uninterrupted line of sight, and are therefore not good for powering objects around the home.

A UK company called Splashpower has also designed wireless recharging pads onto which gadget lovers can directly place their phones and MP3 players to recharge them.

The pads use electromagnetic induction to charge devices, the same process used to charge electric toothbrushes.

One of the co-founders of Splashpower, James Hay, said the MIT work was "clearly at an early stage" but "interesting for the future".

"Consumers desire a simple universal solution that frees them from the hassles of plug-in chargers and adaptors," he said.

"Wireless power technology has the potential to deliver on all of these needs."

However, Mr Hay said that transferring the power was only part of the solution.

"There are a number of other aspects that need to be addressed to ensure efficient conversion of power to a form useful to input to devices."

Professor Soljacic will present the work at the American Institute of Physics Industrial Physics Forum in San Francisco on 14 November.

The work was done in collaboration with his colleagues Aristeidis Karalis and John Joannopoulos.

Notice from saint-michael:

copied from here http://news.bbc.co.uk/2/hi/technology/6129460.stm . Posting rights suspended for 3 days and warning increased.

[shadowx 0]

Dude put all copied text into quotes or you will never get hosted here. Edit every post yu made that contains copied text and quote it. And as for wireless energy transfer unless they can use the energy transferred to create electrical energy it will be pointless. They could do this by using electro-magnetic waves and using induction to create electricity and if they did that i could see it being useful. But then the problem would be if you were wearing a ring or something you'd get electrocuted not so useful. And tin/aluminium foil in the kitchen could be deadly! Ha!

[fffanatics 0]

This could be useful but if you look into Samsungs new fuel cell batteries that can last roughly a month when ran 8 hrs a day, 5 days a week without being recharged, whats the need (Release date roughly late 2007). The only thing this could do is help with the month recharge.

[FLaKes 0]

I bet they would release something like this if it was really that dangerous. They would find a way to make it safe. Wow, will those fuel cell batteries work for notebooks? Imagine that, they would almost never need to be plugged anymore, that would rock.

[heavensounds 0]

Hm..yeah I was thinking a lot about that and thought that this is practically impossible. It seemed wierd to me that almost anything nowadays can travel through air wireless like internet, radio, mobile phones and any other data but I gues that electricity is something different and is not just some sort of data transfer but energy transfer and that is a LOT different...If they ever manage to create such a thing, it would be very usable I guess..

[heini 0]

Hey pplI dont knwo if thet are going to get it right and how...But it would be great. Just think about how much space we would save and how much easier life would be...Kewl man

[juice 0]

Electricity is just the flow of electrons so if one could send those electrons whizzing off in a desired direction and another device catches them then we should have mobile electricity.

[hybridsystem 0]

This has already been done hasn't it? I am sure that I have seen this somewhere...

Thinkgeek. That was it. I saw this on Thinkgeek.com I was a remote power adapter with a PC fitting on one end and a UK wall plug fitting on the other, it could transmit power over something like 130 meters (in a field with nothing in the way, like sheep or people, you know normal field stuff). Though you would only need it for like 5 meters or something. Imaging if they fit this into like lamposts or something like they are doing with Wireless Internet Technology, I could surf all the time, like 24/7 on my laptop! Now we just need to get rid of my nemesis sleep...

Anyway, I'll link you to what I saw...

http://www.thinkgeek.com/stuff/41/wec.shtml

There you go. I just checked as well; wireless power over 300 feet! Awesome!

[elhadi 0]

Thaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaankssorry i can't speak english well