When you think of solar power, you think of the sun’s rays providing the source for the power.  Well the US Department of Energy’s Idaho National Laboratory is changing that concept by providing a method of harvesting the sun’s energy even after the sun has set.

The Idaho National Laboratory (INL) has announced that a team of researchers has developed a thin sheet of plastic containing billions of nano antennas that are able to collect solar energy even after the sun has gone down.  The process is cheap and once collection and storage issues are perfected, will revolutionize the solar industry.

The tiny antennas absorb mid-infrared rays.  Infrared rays are constantly emitted by the earth as heat after absorbing energy from the sun.  Because these infrared rays are being constantly emitted, the nanoantennas can absorb the energy both day and night.

The nanoantennas may also prove to be useful as cooling devices for any object (computers, buildings) or process (coal fired plants) that gives off heat since the heat is usually emitted as infrared radiation. 

"Every process in our industrial world creates waste heat," says INL physicist Steven Novack. "It’s energy that we just throw away." Novack led the research team, which included INL engineer Dale Kotter, W. Dennis Slafer of MicroContinuum, Inc. (Cambridge, Mass.) and Patrick Pinhero, now at the University of Missouri.

The nanoantennas are actually tiny golden spirals or squares that are stamped onto polyethylene.  The nanoantennas are able to absorb about 80 percent of the energy contained in the infrared wavelengths which causes the nanoantennas to oscillate with alternating current a trillion times per second. 

A special “rectifier” has to be created to translate those alternating current oscillations into usable direct current.  Existing rectifiers are unable to work with such high frequency oscillations. 

The research team will have to develop nanorectifiers.  As Dale Kotter, an INL engineer put it:

a nanoscale rectifier would need to be about 1,000 times smaller than current commercial devices and will require new manufacturing methods. Another possibility is to develop electrical circuitry that might slow down the current to usable frequencies

Once the nanorectifiers are perfected and the manufacturing methods scaled up for both the nanoantenna sheets and nanorectifiers, this technology will be cheaper than current solar cell technology.  Current solar cells only capture about 20 percent of the visible spectrum only during daylight hours.  Nanoantennas capture about 80 percent of the invisible infrared spectrum around the clock which would make them a much better investment for alternative energy production.

This technology is expected to be available within the next three to six years.  Rather than solar cells on the roof, you may have nanoantennas/nanorectifiers on the surface of your home, your computer, your handheld gadgets, your TV, … you get the drift.  These new materials may wind up on the surface of any conceivable object that generates heat.

via The Idaho National Laboratory

Related:

For portable energy use the Solar Stik

Solar Groves and Solar Veils transform the landscape

Solar Impulse will fly only on solar power

Sunlabob in Laos rents solar power systems so should U.S. companies

Swiss GOLDFISH project includes a solar submarine

Entry was posted on Thursday, August 14th, 2008 at 3:15 pm under Green Technology, Science and technology.  Print This Post

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