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Thread: Wireless Energy for all mankind?

  1. #1 Wireless Energy for all mankind? 
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    How many things are wrong with my assumptions, and what can be fixed?

    Imagine if someone was able to create a generator that emitted radio waves or lower frequency radio waves, for the purpose of being absorbed by antennas in cars, computers, houses, etc as wireless energy?
    it is possible: http://www.biofuelswatch.com/energy-from-radio-waves/
    but what kind of power would be needed to broadcast such waves in usable amounts?
    What would be the optimum wavelength?
    How dangerouse would it be to organic matter?

    I'm looking or wavelengths that are unallocated, and the us goverment says the only frequency range unallocated is from 3kHz to 9Khz, which has a wavelength of 50,000km to 100,000km
    http://www.ntia.doc.gov/osmhome/allochrt.pdf
    can that be viable?
    is that very hazardous to all life on earth?
    assuming that we could generate the energy required, could this actually power anything on earth and in near-space?


    thanks


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  3. #2  
    Veracity Vigilante inow's Avatar
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    I didn't look at your links, but it sounds like something Nicolas Tesla came up with back in the 1890s.


    http://en.wikipedia.org/wiki/Wireless_energy_transfer


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  4. #3  
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    Here you go.

    http://news.bbc.co.uk/2/hi/6129460.stm

    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.


    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.


    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.

    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.

    Discuss engineering problems and safety the OP wanted.
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  5. #4  
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    i'm not a fan of wireless, only in some situations - it is less efficient and more prone to mistakes, apart from zapping anything that gets in its path if at a high enough energy level...........

    to the original OP (please correct me someone if I am wrong) all forms of wireless communication (TV signal, wireless internet, mobile phones etc) are wireless power just in very small amounts only difference being they use frequency modulation and other techniques to variate the signal which are then 'read' as a colour image (for example)............
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  6. #5  
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    Futreves: like nec207 was saying, check out http://en.wikipedia.org/wiki/Inductive_charging and http://news.bbc.co.uk/1/hi/technology/7819732.stm . It's short range stuff, but it's kind of what you were asking about. The energy density of radio waves is pretty low, so whilst a radio does pick up energy from its antenna, it isn't enough to be practical, especially for long wave radio where the frequency is high and the energy low. Especially since most of the energy is just blasting out into space and going to waste. See inow's link too, Tesla was a smart guy, note this bit:

    2008: Intel reproduces Tesla's original 1894 implementation of electrodynamic induction and Prof. John Boys group's 1988 follow-up experiments by wirelessly powering a nearby light bulb with 75% efficiency.
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  7. #6  
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    the article does say that it won't affect people as they won't be resonating at the same frequency and that most energy not used will find its way back to the transmitter................

    on the side, won't the transmission cause people to resonate at the transmission frequency? at least it will be trying to make them resonate?
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  8. #7  
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    thats what tesla wanted to do, problem is that you lose alot of power(^2) as distance increases......



    close range is better.........

    http://www.berryreview.com/2009/10/3...-charging-pad/
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