Michael Kanellos
A glass for Boosting PV and Solar Thermal Efficiency July 17, 2008 at 4:16 PM
Xerocoat wants to pull off the triple in the solar world: sell the same product to solar thermal, crystalline PV and thin film manufacturers.
The Redwood City-based company has come up with an anti-reflective, porous glass coating that can boost the efficiency of solar components by essentially preventing incoming solar energy from bouncing.
The material can increase the relative efficiency of crystalline solar panels by approximately 3 percent, according to CEO Tom Hood. Over a 25-year period, that results in 4 percent more kilowatt hours generated by the same panel, he claimed. By integrating the coating, manufacturers can effectively upsell their panels.
“We increase the nameplate capacity,” he said. Right now, only around 5 percent of PV makers apply supplementary anti-reflective coatings to their panels, he added.
In solar thermal systems, the coating is applied to the external glass tube of the concentrator. (Concentrators in traditional solar thermal systems contain two vacuum-sealed tubes: an external one that lets heat in and shields the internal tube from the elements, and an internal tube that holds oil that gets heated by the sun’s energy. )
The company is currently conducting a trial with a U.S. solar thermal company building a 1 megawatt demonstration plant in California.
The coating is applied as a liquid. When cured, pores measuring five to 20 nanometers across permeate it. Xerocoat expects key patents for its process to issue later this year. Nth Power and Southern Cross Venture Partners have invested in the company.
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1. The accumulation of dust and organic contaminants on the covering glass of a solar panel
could easily reduce its solar transmittance to below 60% and the solar panel performance
would be decayed significantly. Usuanlly, porous surface is much easier to get dirt. Does
Xerocoat have any solutions other than periodical clean? Our experience shows that Keep the
covering glass clean is much more important than simply decreasing its reflectivity.
2. The technology is very similar to a US patent of Low Refractive AR coating.