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cousinbirgco
Joined: 15 Aug 2008
Posts: 148
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 Posted: Sun Jan 18, 2009 3:31 pm Post subject: Closer to a Solar Panel Breakthrough? |
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We may be closer to a economically viable PV solar panel
than ever before. What do you think?
Solar Power Game-Changer: “Near Perfect” Absorption of Sunlight, From All Angles
A new antireflective coating developed by researchers at Rensselaer could help to overcome two major hurdles blocking the progress and wider use of solar power. The nanoengineered coating, pictured here, boosts the amount of sunlight captured by solar panels and allows those panels to absorb the entire spectrum of sunlight from any angle, regardless of the sun’s position in the sky.
Credit: Rensselaer/Shawn Lin
Researchers at Rensselaer Polytechnic Institute have discovered and demonstrated a new method for overcoming two major hurdles facing solar energy. By developing a new antireflective coating that boosts the amount of sunlight captured by solar panels and allows those panels to absorb the entire solar spectrum from nearly any angle, the research team has moved academia and industry closer to realizing high-efficiency, cost-effective solar power.
“To get maximum efficiency when converting solar power into electricity, you want a solar panel that can absorb nearly every single photon of light, regardless of the sun’s position in the sky,” said Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university’s Future Chips Constellation, who led the research project. “Our new antireflective coating makes this possible.”
Results of the year-long project are explained in the paper “Realization of a Near Perfect Antireflection Coating for Silicon Solar Energy,” published this week by the journal Optics Letters.
An untreated silicon solar cell only absorbs 67.4 percent of sunlight shone upon it — meaning that nearly one-third of that sunlight is reflected away and thus unharvestable. From an economic and efficiency perspective, this unharvested light is wasted potential and a major barrier hampering the proliferation and widespread adoption of solar power.
After a silicon surface was treated with Lin’s new nanoengineered reflective coating, however, the material absorbed 96.21 percent of sunlight shone upon it — meaning that only 3.79 percent of the sunlight was reflected and unharvested. This huge gain in absorption was consistent across the entire spectrum of sunlight, from UV to visible light and infrared, and moves solar power a significant step forward toward economic viability.
Lin’s new coating also successfully tackles the tricky challenge of angles.
Most surfaces and coatings are designed to absorb light — i.e., be antireflective — and transmit light — i.e., allow the light to pass through it — from a specific range of angles. Eyeglass lenses, for example, will absorb and transmit quite a bit of light from a light source directly in front of them, but those same lenses would absorb and transmit considerably less light if the light source were off to the side or on the wearer’s periphery.
This same is true of conventional solar panels, which is why some industrial solar arrays are mechanized to slowly move throughout the day so their panels are perfectly aligned with the sun’s position in the sky. Without this automated movement, the panels would not be optimally positioned and would therefore absorb less sunlight. The tradeoff for this increased efficiency, however, is the energy needed to power the automation system, the cost of upkeeping this system, and the possibility of errors or misalignment.
Lin’s discovery could antiquate these automated solar arrays, as his antireflective coating absorbs sunlight evenly and equally from all angles. This means that a stationary solar panel treated with the coating would absorb 96.21 percent of sunlight no matter the position of the sun in the sky. So along with significantly better absorption of sunlight, Lin’s discovery could also enable a new generation of stationary, more cost-efficient solar arrays.
“At the beginning of the project, we asked ‘would it be possible to create a single antireflective structure that can work from all angles?’ Then we attacked the problem from a fundamental perspective, tested and fine-tuned our theory, and created a working device,” Lin said. Rensselaer physics graduate student Mei-Ling Kuo played a key role in the investigations.
Typical antireflective coatings are engineered to transmit light of one particular wavelength. Lin’s new coating stacks seven of these layers, one on top of the other, in such a way that each layer enhances the antireflective properties of the layer below it. These additional layers also help to “bend” the flow of sunlight to an angle that augments the coating’s antireflective properties. This means that each layer not only transmits sunlight, it also helps to capture any light that may have otherwise been reflected off of the layers below it.
The seven layers, each with a height of 50 nanometers to 100 nanometers, are made up of silicon dioxide and titanium dioxide nanorods positioned at an oblique angle — each layer looks and functions similar to a dense forest where sunlight is “captured” between the trees. The nanorods were attached to a silicon substrate via chemical vapor disposition, and Lin said the new coating can be affixed to nearly any photovoltaic materials for use in solar cells, including III-V multi-junction and cadmium telluride.
Along with Lin and Kuo, co-authors of the paper include E. Fred Schubert, Wellfleet Senior Constellation Professor of Future Chips at Rensselaer; Research Assistant Professor Jong Kyu Kim; physics graduate student David Poxson; and electrical engineering graduate student Frank Mont.
Funding for the project was provided by the U.S. Department of Energy’s Office of Basic Energy Sciences, as well as the U.S. Air Force Office of Scientific Research.
Published November 3, 2008 Contact: Michael Mullaney
Phone: (518) 276-6161
E-mail: mullam@rpi.edu |
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csintexas
millennium club
Joined: 06 Feb 2006
Posts: 2174
Location: USA
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| Posted: Mon Jan 19, 2009 8:42 am Post subject: |
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Well, I think we hear about a lot of technology which might make our lives better in the future. Back in the fifties nuclear power was the big thing.
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http://bcshdb.blogspot.com >
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cousinbirgco
Joined: 15 Aug 2008
Posts: 148
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| Posted: Mon Jan 19, 2009 5:03 pm Post subject: |
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True, but I don't see a downside to this considering the alternatives.
I think the minute we have a panel that is competitive with fossil
fuel and with no negative environmental impact
(see previous article) we will see a dramatic change for the better.
(but I have been known to be wrong once or twice in my life)  |
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csintexas
millennium club
Joined: 06 Feb 2006
Posts: 2174
Location: USA
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| Posted: Mon Jan 19, 2009 8:18 pm Post subject: |
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I guess if we are going to hope for future green power I will go with that new Blacklight company 'hydrino' process. (that way we can just convert existing power plants)
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Ready Mixer
Joined: 19 Mar 2009
Posts: 3
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| Posted: Thu Mar 19, 2009 12:13 pm Post subject: Windows |
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I read somewhere that they may be trying to incorporate this technology into the windows of office buildings and houses. The sunlight is captured across the windows surface and carried to the cells lining the outside of it. If this were feasible it would significantly cut down on installation costs and make the process streamlined if window manufacturers followed suit and made it priority. Interesting and exciting in my opinion
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LaMarcus
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svenglezz-ASMEIL
Joined: 18 Nov 2004
Posts: 99
Location: Toronto
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| Posted: Thu Mar 26, 2009 8:01 am Post subject: |
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They do have solar blinds now, with the panel being part of the blind.
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