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Intel Claims an Advance In Wireless Power
Many readers are sending in coverage of a demo at Intel's developer forum of a wirelessly powered 60-watt bulb. The NYTimes gives background on Intel's improvement to the 'wireless resonant energy link' technology pioneered at MIT, where researchers achieved 50% efficiency of power transmitted several meters via magnetic fields. Intel reached 75% efficiency. Now they just have to make those coils a lot smaller.
25% of wasted power and goal achieved? Plus a nice pulsating magnetic field in the house? No thank you.
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With all the EMF in the average home, with AC wires in every wall and appliances always running, and as little power as a calculator or wristwatch uses, why they need batteries? It seems like a coil and a rectifier circut should be enough.
I'd probably know why if I were an electrical engineer.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
how about all manufacturors agree on a single plug for their power supplies. Then the companies who make power sockets for offices can make one built into a wall socket. Put that into every meeting room. Suddenly you just need a 1 meter long, very thin cable instead of a lugging a whole kilo of copper around....
10 ?"Hello World" life was simple then
There had to be some truth in emails I received about cooking an egg between 2 cell phone !!
In this field no matter how much you know, You still don't know anything.
Unless I've misunderstood the linked article, this is just the same technique that has been used in transformers for decades - a fluctuating magnetic field created by an AC current through a solenoid inducing power in another solenoid. Sure, 75% efficiency is pretty good for a few metres, but those coils are bloody huge. Anyone care to enlighten me as to whether or not this is actually new?
Alright everyone, today's team building exercise will be to complete this discussion without mentioning Nicolai Tesla! Everyone, let's get together on this and try to avoid mentioning him in this thread and keep it entirely Tesla free! ...oh goddamnit.
unlike the scares surrounding the micro-power electric fields from mobile phones and the virtually non-existent fields from CRTs, the amount of power being emitted by these (enough to power a laptop or lightbulb) might actually be something to get concerned about.
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
Nah Tesla made something better he realized wireless power was stupid but wireless power that is a weapon is smart. http://www.newscientist.com/article/mg17623644.800-tesla-and-tunguska.html
Nikola Tesla demonstrated wirelessly powered fluorescent lights more than 100 years ago.
Nevertheless, it would be interesting to see practical applications and commercial implementations for this old idea, and hopefully help us reduce cable clutter a bit. I just hope that accidentally resonant circuitry in the vicinity of transmitters won't suddenly fry itself and cause random fires.
Magnetic field != radiation. Even a fluctuating magnetic field isn't going to effect humans - I think the issue is more the EM interference a strong fluctuating field can bring about.
assuming his body had a ferrite core and was wrapped in copper wire, or something...
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The house wiring doesn't create much field, electric or magnetic. You would have to be right next to the wire to use it.
Magnetic - The current going out the hot wire is exactly matched by that returning on the neutral. The fields due to the two currents cancel.
Electric - The hot wire has 120 volts on it and that would create an electric field but the neutral and ground wires are right next to it. That means the field, while not completely shielded, does not go very far.
OTOH: some appliances create pretty hefty fields. CRT TVs and monitors, motors and subwoofers come to mind. As long as you're willing to sit your calculator on an old CRT TV, you should be able to power it easily. ;-)
I'd guess that since it's AC, the efficiency is roughly in line with the square of the voltage drop (RMS power, from the dim and distant 1970's when I learnt physics).
So your 14.07% voltage drop works out at around 74% efficient - not far off the 75% claimed by Intel.
One swallow does not a fellatrix make
Well, it isn't *limited* to a few meters, per se. The issue is, basically, that power radiated omnidirectionally drops off as the square of the distance -- and anything that's orbital has a LOT of distance.
One way of dealing with this is using directional beamed power. The proposed space elevator wants to power crawlers that go up the tether, and that's essentially the same problem. They're considering solving it by using lasers that beam power up to the crawlers from the ground. The reason for this is we know how to make directed energy transfer devices -- lasers -- that, while they still drop off as the square of the distance, what started off as a near-point-source at the laser might be a square meter or less at several hundreds of kilometers, rather than several hundred kilometers squared (as is the case with an omnidirectional emitter like a transformer.)
So it's no surprise that these things work, and yes, they could work from orbit, at what we'd consider extremely low efficiency. That's kind of notational, though, because if the power is just going to waste, from our point of view -- all the photons that don't hit earth -- catching any of them and sending any percent of that to the earth already means you're getting more energy than you had to start with. So in a way, efficiency doesn't matter: it's a question of return on investment.
But if we could come up with *safe*, directionally beamed power, then orbital power stations would start to look pretty attractive.
Of course, one possible contender for safe orbital power would be to use the filaments of solar elevators as conductors. (Although the voltages you'd have to use to conduct with reasonable efficiency over a transmission line 36,000 km long mean you'd have to use multiple elevators, with one being your high-voltage line and the other, many miles away, being your current return path, and you run into problems with trying to insulate the HV line from the earth itself.)
Nostalgia's not what it used to be.
... they figure out to encrypt it so people can't steal my wireless power.
now we need to go OSS in diesel cars