Wireless Electricity

Intro

Wireless energy transfer or wireless power involves the transmission of electrical energy from a source to an electrical load without wires connecting the two. Recently, much research has been done on improving this field of technology. Before we get into the physics, let`s take a look at the origins of wireless electricity. 

Nikola Tesla 

The first origins of wireless electricity research can be traced back to over a century ago. After discovering that Alternating-Current (the flow of electrons through a conductor back and forth) creates a magnetic field around the conductor. Alternatively, he found that wires placed inside the magnetic field will also conduct AC. He thought if he could generate a strong enough magnetic field using an AC current, he could transmit the energy through space to a load which was some distance away, and thats exactly what he did. Over a distance of 26 miles, he transmitted 100 million volts of electric power wirelessly and powered 200 light bulbs and one electric motor!

How it works exactly

The general physics behind transmitting power is relatively simple. All magnetic fields are projected at a certain frequency. When you create a magnetic field around an AC source, the key is to then match the resonant frequency of the power source to the frequency of the load in order to pick up the transmission with the most efficiency. The device then converts the magnetic field back into AC or electric energy. 
When the transmitter field and the receiver field are tuned to the same frequency, the resonance energy is able to be transferred over large distances while leaving the surroundings unaffected. Without resonance, the system becomes very inefficient. 

Applications

The implications of this technology are HUGE. Whether its reducing clutter in households, offices, and factories by removing all of the obsolete wires, or greatly reducing infrastructure costs of different regions, the wireless potential could change society very significantly. Currently, researchers are focusing on increasing the distance and efficiency of wireless systems. The Japanese started the first commercial wireless electricity experiment in 2008. The test is supposed to transfer about 1200 watts of power to distances 300 feet away using magnetically coupled resonance. The Japanese government believes that the main application of this power will be to charge electric vehicles around the city. Chargers that would pick up the magnetic field created would automatically re-charge cars without any plugging-in needed. To promote this idea, the government has envisioned thousands of free charging spaces located around the city! If this experiment is a success, many other societies may choose to apply this technology to their own cities. 

In the near future, all electronic devices (such as cellphones, iPods, remotes) will have antennas in place of batteries and will draw from a centralized power node in each building. This will also eliminate the need for multiple wall sockets and bulky cables.

Question

How is wireless communication different than wireless electricity? (Think energy and efficiency)



Answer:

The amount of energy received in wireless communication is only critical if there is not enough to distinguish the signal from interference from background noise. With wireless power, the efficiency of the energy transfer is what determines whether the system is economical or not.  

Bibliography

http://thetechjournal.com/science/mit-witricity-team-powers-two-devices-with-wireless-electricity.xhtml

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

http://engineersworld.wordpress.com/2011/01/07/wireless-electricity/

http://www.scienceinseconds.com/episodes/Wireless-Electricity

http://home.earthlink.net/~drestinblack/wireless.htm

http://www.alien-ufos.com/computers-astronomy-science-technology/16403-holy-grail-power-tesla-wireless-electricity-test-japan.html