Much better wireless power transmission possible - boffins
Cars yes, Heinlein broadcast-juice 'broomsticks' not yet
Engineering boffins in the States say they're on the track of a method to hugely improve the transmission of electrical power without wires.
The developments, reportedly, could mean that it wouldn't be just laptops or smartphones charging up wirelessly - much more powerful devices like cars might also get their power without benefit of wires or plugs.
The research is reported by in-house service Duke Engineering News, covering the activities of engineers at Duke uni in North Carolina.
Essentially the problem with wireless power transmission at the moment is that it requires very short range, almost in contact - as with "charging mats" used for small devices - and even so it still suffers from low efficiency. This isn't too much of an issue when dealing with the tiny power inputs required for charging up small batteries, but in high-power applications it would mean wasting a lot of money. Worse, all the waste power would have to go somewhere - probably manifesting itself as dangerous amounts of heat and leading to fires or even explosions.
“We currently have the ability to transmit small amounts of power over short distances, such as in radio frequency identification (RFID) devices,” says Yaroslav Urzhumov, electrical and computer engineering prof at Duke. “However, larger amounts of energy, such as that seen in lasers or microwaves, would burn up anything in its path."
According to Urzhumov, one possible solution is to employ the new and sexy class of artificial "metamaterials", already the subject of much attention for their potential ability to bend radar beams and/or light rays to create "invisibility cloaks" (or anyway invisible sheds) and such like.
A metamaterial stealth shed is, as far as light or radar is concerned, not actually there: in essence the idea here - as explained by Urzhumov - is to use metamaterials at the transmitting and receiving end of the power jump to make it seem as though the intervening space is not there.
“Based on our calculations, it should be possible to use these novel metamaterials to increase the amount of power transmitted without the negative effects,” says the prof. “The system would need to be tailored to the specific recipient device, in essence the source and target would need to be ‘tuned’ to each other."
According to Duke Engineering News, interviewing the prof, the new tech "should theoretically make it possible to improve the power transfer to small devices, such as laptops or cell phones, or ultimately to larger ones, such as cars or elevators, without wires".
Electric cars able to draw power across reasonable gaps might be charged up in the same fashion as phones now can be using mats: or even, perhaps, do away with their batteries altogether and run on energy transmitted from power stations miles away. A world running on broadcast power was imagined long ago by Robert A Heinlein in his story Waldo: in such a future many things more exciting than electric cars would be possible, such as broomstick-like air vehicles able to fly to space stations in orbit.
Miraculous deKalb power receptors probably aren't on the cards: but the metamaterials research is interesting nonetheless. Urzhumov's investigation grows out of previous research into cloaks, metamaterial "superlenses" and metamaterial power transmission work at Mitsubishi Electric Research Labs. The work is funded by the US military. ®
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