Volume 45, Issue 9 - September 2010


technology news
New Technique Could Turn Windows into Transparent Power Generators

An international team of scientists and industrialists is working at the University of Leicester to develop a new technique for harnessing the sun’s energy.

EnSol AS in Norway has patented a thin film solar cell technology that it seeks to develop commercially by 2016. The company is now working with experts in the University of Leicester Department of Physics and Astronomy to develop the new type of solar cell material that could be coated as a thin film on, for example, windows in buildings to produce power on a large scale.

Chris Binns, professor of Nanotechnology at the University of Leicester, says the collaboration offers a tremendous opportunity to develop a new method for harnessing solar energy. “The material has been designed by EnSol AS and is based on nanoparticles that can be synthesized in Leicester. In fact, following some initial investment by the company, the equipment we have here at the University of Leicester is uniquely suited in the world to produce small amounts of the material for prototypes.”

Binns adds, “The work is important since the solar cells are based on a new operating principle and different to Si solar cells. One of the key advantages is that it is a transparent thin film that can be coated onto window glass so that windows in buildings can also become power generators. Obviously some light has to be absorbed in order to generate power, but the windows would just have a slight tinting (though a transmission of only 8 to 10 percent is commonplace for windows in the ‘sun belt’ areas of the world). Conversely, the structural material of the building can also be coated with a higher degree of absorption. This could be side panels of the building itself, or even in the form of ‘clip-together’ solar roof tiles.

“Also, since it is a thin film that can be coated onto large areas, it could become very much cheaper than conventional devices.”

The material is composed of metal nanoparticles (diameters ~ 10 nm) embedded in a transparent composite matrix.
A spokesperson for EnSol AS stated in a company news release: “The basic cell concept has been demonstrated, and it will be the objective of this research and development project to systematically refine this PV cell technology to achieve a cell efficiency of 20-percent or greater.”

The two organizations will collaborate to design and construct a thin film deposition system with nanoparticle source for fabricating prototype cells based on this design. The experimental facility will be designed to produce PV cells with an active area in excess of 40- by 40-mm deposited onto standard glass substrates. These prototype cells will then be characterized and tested by the partners.

The EnSol spokesperson added, “EnSol’s next generation PV cell technology has tremendous potential for industrial scale, low environmental impact, cost-effective production via standard ‘spray on’ techniques.”
www.ensol.no, www.le.ac.uk


EcoGuard® Outperforms Standard Solar Mirrors, Study Says
Guardian Industries in Auburn Hills, Mich., has announced the results of a performance study that shows EcoGuard Solar Boost-LP, its laminated parabolic mirror for concentrated solar power (CSP) applications, features a solar reflectance better than standard 4-mm monolithic mirrors currently used in most large solar fields. Tests conducted by the National Renewable Energy Laboratory (NREL) showed that EcoGuard Solar Boost-LP has a solar reflectance of 96.75, better than any measured 4-mm monolithic mirror.

NREL reported Guardian’s laminated glass reflector has an initial solar-weighted hemispherical (SWV) reflectance of 96.75 ± 0.09. It has an initial specular reflectance of 95.86 ± 0.08 into a 25-mrad cone angle and 7-mrad of 94.93 ± 0.97. NREL is testing the product’s long-term durability as well.

“The CSP industry needs mirrors that will remain highly reflective for 30-plus years with little to no degradation and will help lower the cost of electricity generated by CSP to be competitive with natural gas,” says NREL senior scientist Cheryl Kennedy.

PPG Introduces Solarphire NaB Glass for PV Aplications
Pittsburgh-based PPG Industries has introduced Solarphire NaB glass for solar applications where sodium leaching can adversely affect the performance of solar panels, reflectors, water heaters and other devices. The glass is formulated with a transparent barrier coating that retards the migration of sodium (Na) and other alkalis to the surface during high-temperature processing or long-term field exposure.

Solarphire NaB glass is temperable and highly durable, and suits virtually any solar application because the coating can be used on the first or second surface as needed. The glass is approved for concentrating photovoltaic and concentrating solar power applications where high in-use temperatures may be encountered.

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