July 25, 2009 – Vol.14 No.18
TESLA’S DREAM COMES TRUE. ALMOST.
by Bruce Muliiken, Green Energy News
Imagine ordinary cars that had no wiring harness. Imagine homes that didn’t have a network of wires buried in the walls. Imagine electric vehicles whose batteries could be charged without plugging in.
Stop imagining. Start thinking about implementing and commercializing wireless electricity into our buildings, our vehicles and with every electronic and electrically powered device we own. It looks as though (though, no guarantees) that inventor/engineer/scientist Nikola Tesla’s dream of transmitting power through thin air is here. (But not quite as he imagined it.)
Watertown, Massachusetts-based WiTricity notes in an interview on BBC that its technology of transmitting power by way by of resonant magnetic coupling could begin showing up in commercial products in as little as a year. The company in its website describes resonant magnetic coupling: ”Magnetic coupling occurs when two objects exchange energy through their varying or oscillating magnetic fields. Resonant coupling occurs when the natural frequencies of the two objects are approximately the same.”
The company has developed its proprietary magnetic coupling technology to the point where energy can be transferred from as little as a few centimeters to as far as several meters.
Again the website: “ WiTricity power sources and capture devices are specially designed magnetic resonators that efficiently transfer power over large distances via the magnetic near-field. These proprietary source and device designs and the electronic systems that control them support efficient energy transfer over distances that are many times the size of the sources/devices themselves.”
WiTricity dreams of many applications for its technology:
--- Small battery powered devices, cell phones, music players, cameras and the like, could be recharged without plugging in. Magnetic resonance sources could be recharging these devices as soon as they were in range.
--- Larger electronics, like flat screen TVs, could be wall mounted without dangling wires or the need for custom hidden wiring. A magnetic resonator source in the room would supply power to a magnetic resonance receiver inside.
--- Wireless and batteryless desktop computer peripherals such as mice, keyboards and speakers would be possible with one souce powering all the devices.
--- In the industrial scene, think wireless industrial robots, cordless tools, and automated guide vehicles all powered from nearby or centralized magnetic power sources.
--- The technology used in cars would mean the elimination of most of a vehicle’s wiring harness. The magnetic source could power lights, power windows, wipers, etc without the need for connecting wires.
--- And battery powered vehicles too could benefit. No need to plug in. Park over a magnetic source and wait: no physical connection between and the power source and the vehicle’s battery pack.
What the company says could be only just the beginning:
--- Since the technology will allow a few kilowatts to be efficiently transmitted whole buildings could be wired with just strategically placed magnetic resonance sources. Further, combining WiTricity’s technology with EnOcean’s wireless, batteryless, self-powered switching technology (now fully commercialized) would allow lighting and other systems to be installed without wiring. Appliances too, would be able to operate without a cord and wall socket. Walls wouldn’t be a barrier to the technology; common building and furnishing materials, such as wood, gypsum wall board, plastics, textiles, glass, brick, and concrete are essentially “transparent” to magnetic fields, according to WiTricity.
--- Similarly, existing buildings could be rewired using the WiTricity / EnOcean combination above with less damage and repair of walls and ceilings.
--- The technology too could help commercialize electric and plug-in hybrid cars. If magnetic resonance sources were installed in the pavement of millions of parking spots every time a vehicle pulled in, recharging could begin automatically, no plugging in by the driver. Simplified charging would lead to more frequent charging. More frequent charging could translate into smaller battery packs and reduce the cost of vehicles. More frequent charging could also mean less expensive battery solutions could be employed in vehicles: tried and true lead acid batteries might make a comeback in electric vehicles.
--- Distributed and renewable energy systems could benefit as well. Rooftop solar power systems could be installed without physical connections to a building’s electric wiring system. Ditto for roof-mounted wind turbines.
According to the company the technology is safe: Magnetic fields interact very weakly with biological organisms – people and animals – and are scientifically regarded to be safe.
And it’s efficient: The power transfer efficiency of a WiTricity solution depends on the relative sizes of the power source and capture devices, and on the distance between the devices. Maximum efficiency is achieved when the devices are relatively close to one another, and can exceed 95%, says WiTricity.
WiTricity claims to be the first company to be able to transmit energy across room scale distances. Other companies, including WiPower, eCoupled and Powermat are working on similar, but shorter distance, wireless power transmission.
Tesla’s dream was to transmit power over long distances eliminating the need for a power grid. This isn’t that, but it’s very interesting nonetheless.
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