Self-Cleaning Coating Wins Funding
The United States Department of Energy Solar Energy Technologies Office has recently awarded Arizona State University spin-out company, Swift Coat, $1 million to commercialize a dirt-eating solar glass coating that also aims to increase energy generation.
Swift Coat specializes in nanocoatings and was founded by ASU associate professor Zachary Holman and doctoral student Peter Firth. Partners on the award include a U.S.-based glass manufacturer and the National Renewable Energy Laboratory.
About the Coating
Using two coatings—a preexisting antireflection coating and a photocatalytic titania (titanium dioxide)—Swift Coat is aiming to create a material that both repels dirt and breaks down organic compounds.
“Everyone has seen how dirty their windows can get after a dust storm, but few realize the same happens to their solar panels.” says Peter Firth, Swift Coat CEO. “This buildup of dirt can reduce the power output of panels by up to 30% and, if you aren’t the type to climb up on your roof and clean them, this loss of efficiency can persist for months.”
Over the 18-month program, Swift Coat will be using titanium dioxide to develop the photocatalytic titania coating. When absorbing UV light, the material creates a chemical reaction that breaks down organic soilants.
“Titania-containing coatings have been used for self-cleaning—with 15 years of field data—in the residential windows market, but those coatings have much too high reflectance to be considered for PV module glass,” said Holman.
Once developed, the coating will be applied using a technique that sprays dry nanoparticles through a gas deposition process called “aerosol impact-driven assembly.” In choosing this type of application, the coating avoids possessing a high refractive index and thus matches the industry standard for anti-reflection coating performance.
Additionally, the coatings applied make the module surface hydrophilic, making it easier for rain or dew to wash away the already loosened inorganics.
While the coatings could potentially increase energy generation by 3% over standard panels, it would also reduce operation and maintenance costs due to its self-cleaning properties. When completed, Swift Coat’s hardware aims to coat single-module-wide coating line at 10 meters-per-minute, producing roughly 300 60-cell solar modules per hour.
The company hopes to have a commercialized product on the market for manufacturers by 2021. No pricing information on the developing product has been released, but is expected to be similar to existing standard anti-reflective coating materials and processes.
“Our business model is not to manufacture and sell the whole coating machine to our customers, who are glass coaters or module manufacturers, but rather to manufacture and sell our coating “sources”—hardware that can be integrated into any vacuum coater—and to also provide our customers with the precursor materials that are fed into these sources to create the coatings,” said Swift Coat’s CFO, Matthew Firth.