The days of wires powering electronic devices could soon be at an end, with the development of a new system that will allow laptops, mobile phones and televisions to be left unplugged in the home while being recharged.
The new technology exploits a recent breakthrough in physics, according to the US company WiTricity.
It has shown that it can send electricity “wirelessly” through the air and can switch on a light bulb or keep a computer running.
“Let’s face it: wires .,” Eric Giler, chief executive of WiTricity, said at the TEDGlobal conference in Oxford this week.
“Batteries also ..” The new system has the potential to do away with mountains of disposable batteries and miles of wiring.
“There is something like 40 billion disposable batteries built every year for power that, generally speaking, is used within a few inches or feet of where there is very inexpensive power,” Mr Giler said.
The system is able to operate safely because the energy is largely transferred through magnetic fields.
Mr Giler was keen to emphasise safety during the demonstration. “There's nothing going on — I’m OK,”
he said as he walked around a television running on wireless power.
The science behind the system was developed by the physicist Marin Soljacic at the Massachusetts Institute of Technology.
After being woken on three consecutive nights by the “battery low” beep of his mobile phone, he wondered:
“Why can’t all this electricity in the walls just come out and power my phone?”
Professor Soljacic took advantage of the principle of resonance, whereby the transfer of energy becomes more efficient when a certain frequency is applied. When two objects have the same resonant frequency, they exchange energy without having an effect on surrounding objects. Acoustic resonance causes glasses to smash when a singer hits a specific note; WiTricity uses the resonance of low-frequency electromagnetic waves.
The WiTricity system works by transferring energy between two magnetic coils. The first coil is placed in a box attached to a home’s electricity mains, and can be embedded in a wall or ceiling. The second coil is attached to a device such as a television or laptop. Electromagnetic waves are transferred between the two coils and the second coil absorbs energy.
The Institute of Physics in London confirmed that the technology was safe, as it used a magnetic field that “had no detrimental effects on the human body”.
There are drawbacks, though. Only smaller devices can be charged, and they must be within two metres of a wall that provides wireless power — although it is hoped that the range can be extended to as much as 30 metres.
Wireless technology has been demonstrated before, including systems that use lasers. Researchers said that WiTricity’s technology was a breakthrough because the system did not require a clear line of sight between the charger and the device.
Source: http://nicefun.net/electricity-wirelessly-through-the-air-vt29192.html#p54197