Gnawing the knuckle that knocks it
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Boffins build cheap solar sheets
A GROUP OF researchers at the US Department of Energy's Idaho National Laboratory (INL) say they have found an inexpensive way to produce plastic sheets that can collect heat energy generated by the sun and other sources.
The boffins use billions of nano-antennas, tiny gold squares or spirals set in a specially treated form of polyethylene, which can be mass-produces on flexible materials.
The nano-antennas target mid-infrared rays, which the Earth continuously radiates as heat after absorbing energy from the sun during the day, making them usable both at day and night.
"Every process in our industrial world creates waste heat," says INL physicist Steven Novack. "It's energy that we just throw away."
The researchers played around with a number of materials and found that with the right materials, shape and size, the simulated nano-antennas could harvest up to 92 per cent of the energy at infrared wavelengths.
Kotter explained that the process itself is not new and that others have invented antennas that collect energy from lower-frequency regions of the spectrum, but until now infrared rays have proven more elusive.
Because the nano-antennas absorb infrared radiation they could also be used as cooling devices.
Before we start celebrating the end of the energy crisis, Kotter has pointed out that they currently don't have a way of turning the collected energy into usable electricity.
Basically, the infrared rays create alternating currents in the nano-antennas that oscillate trillions of times per second, but today's rectifiers can't handle such high frequencies.
"We need to design nanorectifiers that go with our nanoantennas," explained Kotter.
He explained that a nano-scale rectifier would need to be about 1,000 times smaller than current commercial devices or alternatively they would have to develop electrical circuitry that might slow down the current to usable frequencies. µ
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People keep going on about 'slowing down global warming' - why? How do we know we haven't actually inadvertently delayed or stopped global cooling? We're already statistically overdue for the next ice age!
"they don't have a way of turning the collected energy into usable electricity"

ah.. so they've invented a bit of plastic that heats up in the sun. well done boys.
This is for heat, not for electricity. Physics says that energy degenerates irreversibly to heat; that's only useful for heating things. (All the energy you use at home, pretty much, quickly becomes heat.) Or, rather, to maximum entropy. You can generate electricity from a heat difference or use electricity or other energy to create a cool and hot difference, but always by increasing the entropy. Blame God for that when you see him, until then we have to live with it. But on the upside, this could have heatsink applications: macroscale, maybe better air conditioning.

...Did you say it's made out of gold? Okay, I'll put it next to my platinum hydrogen-maker (real, but not yet ordered).
Ummm... Not really Nick, all they will do is collect the heat in the tubes, now what you going to do with the hot tubes?

Plus of course the poles receive the least infra-red radiation of any area on the planet, it's all about the angle of incidence.

If you want to cover any area of the planet with anything, it would have to be somewhere on the equator, and far better to cover it with a big mirror just to bounce the heat off back into space... trouble is we have a nice layer of greenhouse gases which will bounce a lot of it back, so it would be far more efficient to get the mirrors above that.

So that's settled then, everyone agreed? We need to invent a couple of hundred square miles of flying mirrors that can cruise a couple of hundred miles up, somewhere near the equator, preferably orbiting the earth once a day so they are at midday in the local time zone all the time.

Anyone want to warn Florida it's going to get dark at midday. (Only picked Florida to annoy the Bush family, cos they *know* global warming doesn't exist!)
@ Nick.

They don't negate heat but instead turn some of the IR wavelengths emitted by 'whatever' to produce an AC current - according to the article at least.

Basically this wouldn't be very effective on a white surface due to the fact that white surfaces are not efficient radiators... the opposite of black surfaces in fact. The wavelengths directly from the sun are less useful for this application due to the smaller amount of incident IR from that source.

An added feature of this is that even with a high efficiency of conversion from IR radiation to electrical current there will still be waste heat present from the material absorbing the heat in the first place. This will be trapped at the surface - nearer than if it was emitted from the surface and absorbed by the atmosphere/particulates and thus increasing the rate of loss of ice from the poles by creating an actual 'greenhouse' effect.... assuming that there wasn't a fast flowing blanket of air moving under and over the material to reduce heat build up.
How about we put some on the equator and make lots of electricity and substitute electricity for generating energy by burning stuff and slow down global warming come?
Mass produced, it would be handy to put them at the poles of the planet to slow down global warming some.
Kynar was a plastic film on the market in the mid-eighties. It was piezo-electric, photo-voltaic and sensitive across a fair band of the spectrum.