Posted on 11/27/2006 6:03:25 AM PST by FLOutdoorsman
You may one day be able to recharge your laptop or mobile phone without having to plug it into the wall, says a US physicist.
But others say there are many hurdles before such transfer of energy means we can say goodbye to wires.
Assistant Professor Marin Soljacic, of Massachusetts Institute of Technology, will present his team's work at the American Institute of Physics forum in San Francisco this week.
Today's wireless transfer of energy, such as the transfer of light energy from the Sun for solar power or the transfer of microwaves from transmitters for communication, involve relatively low levels of energy.
But recharging devices like laptops requires a much higher level of energy. And if this was routinely zapped through the air it could 'fry' any living organisms that get in the way.
But Prof Soljacic says he has found a way of transmitting energy so that only the devices that it is recharging will pick it up, so it will not affect humans.
Instead of using traditional radiation, he wants to use the part of the electromagnetic field that is 'non-radiative'.
He says devices can be tuned to the frequency of this field and thus act as a sink for all the energy the transmitter gives out.
Prof Soljacic says this would prevent energy radiating out to areas it does not need to go to, providing an efficient and safe method of wireless energy transfer.
"The team calculates that an object the size of a laptop could be recharged within a few metres of the power source," he says. "Placing one source in each room could provide coverage throughout your home."
Prof Soljacic also thinks the technology could be used to power freely roaming robots in a factory. Finding a 'magic' frequency
But Australian physicists, yet to see the full details of Prof Soljacic's work, are sceptical of his claims.
They say the challenge is finding a 'magic' frequency that does not also affect living organisms and thus pose possible health risks.
"You would be reintroducing all the problems that we went through with mobile phones," says Dr Geoff Anstis of the University of Technology, Sydney, referring to the uncertainty surrounding any long-term health effects of using mobiles.
"And it wouldn't be until a couple of decades that you may be happy that there isn't a significant problem."
His colleague Professor Geoff Smith agrees and says there are also technical challenges to keeping the devices tuned with the transmitters, thus preventing the general release of stray energy.
"I think this is nice physics but there's a way to go before it would be possible," says Prof Smith.
He says any changes in the surrounding environment could "de-tune" the system and stop the safe and efficient transfer of power.
Electrical engineer Dr Trevor Bird of CSIRO's ICT Centre says attempts so far to develop wireless power transfer have not been very successful.
He agrees that safety and technical barriers to wireless power systems are huge and would like further details on Prof Soljacic's proposal.
Dr Bird also says that, depending on the frequency of the field, the antenna on the device being recharged may have to be very large.
Seriously, I dunno the health implications of having such a system. Thats alot of energy flying around.
So Tesla was right!
BUMPERS FOR AFTERS
Considering probably 90% of the energy sent out by the system will just float up into the ozone, I wonder if they will earn the "Energy Star" label?
Seriously, I dunno the health implications of having such a system. Thats alot of energy flying around.
There is also the uncomfortable reality that even with today's high copper prices, wires are dirt cheap and nearly 100% efficient.
My suspicion is that this will never be workable with a consumer product like a laptop. Maybe they can use it to power things like lunar rovers, etc., but if you can use the sun anyway, I'm not sure what the advantage is.
TANSTAAFL...
The problems are efficiency of the transfer, i.e. how much power is simply lost in the transmission, and the safety concerns with beaming that amnount of power around. You don't want people to feel like they're in a microwave oven.
Hey, piece of cake.
Some folks, not all, mind you, are probably not gonna be happy about setting their laptop on their lap and having this gizmo focusing microwaves in that direction!!!
Someday we might catch up to Tesla.
Well....OK then.
No fair. The original inventor of the cordless extension cord was Stephen Wright.
Non-radiative my tail. But, this could be due to bad reporting. This may be using a capacitance field approach that transfers data and thus energy via the surface capacitance of objects. A network technology was based on this.. Auranet, which played on the name of the shimmer surrounding people viewed in the morning light.
However, I still don't know what the effects of trying to transfer alot of energy via this would be.
I know it can be done. Did something like this for High School Science project.
Now that I think about it further, maybe it would be of use in a lunar rover. The problem with solar is that you've gotta drag those solar panels around with you. Maybe the receivers for this thing would be lighter and more compact.
Of course, its low power and less efficient than a copper wire - its basically a transformer with the primary in the toothbrush holder and secondary in the toothbrush. Perhaps this technology could be expanded upon...
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