New solar product captures up to 95 percent of light energy

May 16, 2011

Efficiency is a problem with today's solar panels; they only collect about 20 percent of available light. Now, a University of Missouri engineer has developed a flexible solar sheet that captures more than 90 percent of available light, and he plans to make prototypes available to consumers within the next five years.

Patrick Pinhero, an associate professor in the MU Chemical Engineering Department, says generated using traditional photovoltaic (PV) methods of solar collection is inefficient and neglects much of the available solar electromagnetic (sunlight) spectrum. The device his team has developed – essentially a thin, moldable sheet of small antennas called nantenna – can harvest the heat from industrial processes and convert it into usable electricity. Their ambition is to extend this concept to a direct solar facing nantenna device capable of collecting solar irradiation in the near infrared and optical regions of the solar .

Working with his former team at the Idaho National Laboratory and Garrett Moddel, an electrical engineering professor at the University of Colorado, Pinhero and his team have now developed a way to extract electricity from the collected heat and using special high-speed electrical circuitry. This team also partners with Dennis Slafer of MicroContinuum, Inc., of Cambridge, Mass., to immediately port laboratory bench-scale technologies into manufacturable devices that can be inexpensively mass-produced.

"Our overall goal is to collect and utilize as much solar energy as is theoretically possible and bring it to the commercial market in an inexpensive package that is accessible to everyone," Pinhero said. "If successful, this product will put us orders of magnitudes ahead of the current solar energy technologies we have available to us today."

As part of a rollout plan, the team is securing funding from the U.S. Department of Energy and private investors. The second phase features an energy-harvesting device for existing industrial infrastructure, including heat-process factories and solar farms.

Within five years, the research team believes they will have a product that complements conventional PV . Because it's a flexible film, Pinhero believes it could be incorporated into roof shingle products, or be custom-made to power vehicles.

Once the funding is secure, Pinhero envisions several commercial product spin-offs, including infrared (IR) detection. These include improved contraband-identifying products for airports and the military, optical computing, and infrared line-of-sight telecommunications.

A study on the design and manufacturing process was published in the Journal of Solar Energy Engineering.

Explore further: Self-cooling solar cells boost power, last longer

More information: Theory and Manufacturing Processes of Solar Nanoantenna Electromagnetic Collectors, J. Sol. Energy Eng.  -- February 2010 --  Volume 132,  Issue 1, 011014 (9 pages) doi:10.1115/1.4000577

Abstract
The research described in this paper explores a new and efficient approach for producing electricity from the abundant energy of the sun, using nanoantenna (nantenna) electromagnetic collectors (NECs). NEC devices target midinfrared wavelengths, where conventional photovoltaic (PV) solar cells are inefficient and where there is an abundance of solar energy. The initial concept of designing NECs was based on scaling of radio frequency antenna theory to the infrared and visible regions. This approach initially proved unsuccessful because the optical behavior of materials in the terahertz (THz) region was overlooked and, in addition, economical nanofabrication methods were not previously available to produce the optical antenna elements. This paper demonstrates progress in addressing significant technological barriers including: (1) development of frequency-dependent modeling of double-feedpoint square spiral nantenna elements, (2) selection of materials with proper THz properties, and (3) development of novel manufacturing methods that could potentially enable economical large-scale manufacturing. We have shown that nantennas can collect infrared energy and induce THz currents and we have also developed cost-effective proof-of-concept fabrication techniques for the large-scale manufacture of simple square-loop nantenna arrays. Future work is planned to embed rectifiers into the double-feedpoint antenna structures. This work represents an important first step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity. This could lead to a broadband, high conversion efficiency low-cost solution to complement conventional PV devices.

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User comments : 16

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wealthychef
5 / 5 (2) May 16, 2011
It's not clear to me why this complements traditional PV tech instead of replacing it.
RTT
5 / 5 (7) May 16, 2011
And where, besides the title, is there any information?? Again we have flash and no substance.
Lost_BiomedE
4.8 / 5 (5) May 16, 2011
Terrible article. There are a few buzz-words and a standard solar article format. No information about the advance to be seen. Are bots writing these now?
flying_finn
not rated yet May 16, 2011
MorituriMax
3 / 5 (4) May 16, 2011
I've got my wallet open, the most important information for me as a consumer was:
1) 90% capture of sunlight.
2) roof shingles.
3) available and affordable within a few years.
Adam
3 / 5 (1) May 16, 2011
The new system is complementary to optical PVs because it currently collects energy from the THz part of the solar spectrum. They haven't yet developed optical rectifiers. But this does make it very useful for thermal energy collection, since it's mostly at THz frequencies.
ClickHere
4 / 5 (4) May 16, 2011
I stopped reading after the first paragraph where the last sentence contradicts the headline.

It should read "Yet to be invented product captures 95 percent of light energy".
ab3a
4.5 / 5 (2) May 16, 2011
Years ago, there was discussion about building a "Rectennna" for receiving power from solar energy satellites. The Rectenna was a microwave receiver that rectified the microwave energy. It was supposed to be pretty efficient.

That same concept could be scaled to light wave frequencies using nano-technologies. I'm just speculating, but it sure reads as if these people are trying to do just that. If it is successful and it can be scaled, this would be a HUGE accomplishment.
Jayman
1 / 5 (1) May 16, 2011
So, is this the real deal? Will this breakthrough answer our prayers to abundant, non-polluting energy for all?
RealScience
5 / 5 (2) May 16, 2011
MurturiMax and Jayman:
No, this is not the real deal. At least not yet.

This currently works in the mid-infrared, where the sun's spectrum has much less energy than the visible portion (so even if the device captured it all it wouldn't be that much).

They PLAN to extend this into the optical portion of the spectrum, where there is much more energy available in sunlight.

The 95% was just in the headline, so don't trust it. To break 30% even with perfect antennae they would need concentrated sunlight (theoretical max 44%), or specific antennae for different wavelengths (theoretical max ~68%), or both (max ~88% with many antenna types and perfect concentration).

But anything anywhere close to perfection is VERY difficult and expensive.

This is an interesting POTENTIAL technology, but it is far from product and even farther from cost effective.

I do wish them luck, though, as it would be great if it worked well and cost-effectively.
mjesfahani
not rated yet May 17, 2011
1 minute saving sun's energy = 1 year supply of energy of the world! very effective.
Eikka
1 / 5 (1) May 17, 2011
Wouldn't an IR solar panel be a Maxwell's Demon, because all warm objects radiate IR.

In essence. Put it in an insulated box, and the box spontaneously cools down below ambient temperature.
Ricochet
1 / 5 (1) May 17, 2011
So, is this the real deal? Will this breakthrough answer our prayers to abundant, non-polluting energy for all?


Let's see how long it takes the power comapnies to shut this one up... It's been proven in the past that if they won't make money from it, they spend money to get rid of it.
bloodyanarch
4.5 / 5 (2) May 17, 2011
Isn't the real issue with solar engergy the conversion from light to usable energy? I mean go ahead and collect 99.999% of the light... if your conversion is only 5% who cares.

I also notcied that there's no info on what the current light collectionis today.. is it 85%? 65%? Does it even matter if 90% of the engergy converted comes from the already collected light?
hemitite
not rated yet May 17, 2011
What I'd like to know is exactly how one would rectify the range of terahertz currents these tiny antennas would be supplying to the 60 hertz stuff we all know and love?
RealScience
not rated yet May 17, 2011
mjeefahani - it is more like 1.5 hours of the sunlight to equal humanity's yearly consumption, and that is at 100% conversion efficiency (but sunlight is still a lot of energy).

Eikka - a Far IR solar panel using photons at ambient temperature would indeed be a Maxwell's demon, but this uses shorter IR wavelengths.

Bloodyanarch - yes, the conversion is the most important - capturing more just means more available to convert. (Capturing more without converting more would actually be bad, as it would produce more heat to get rid of.

Hemitite - not only is it terahertz, but to be efficient there will be many different frequencies. So the easiest is to convert everything to DC, and then convert the DC to the 60 Hz AC (or 50 Hz in other countries).

Converting terahertz to DC could be done with pairs of diodes, similar to the way a lower frequency would be converted.