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Desert solar farms could use self-cleaning solar panels

The researchers found that 90 percent of deposited dust can be removed by the transparent screen in fewer than 60 seconds.

Self-cleaning solar panels could find use in the dusty environs of Arizona, the Middle East or Mars, Scientific American, By Larry Greenemeier, Aug 22, 2010, The best places to collect solar energy are also some of the dustiest on Earth and beyond, a quandary that leads to inefficiencies in how well the cells are able to convert strong sunlight into renewable electricity. The solution, according to new research, is to coat solar cells with material that enables them to chase away dirt particles on their own with the help of dust-repelling electrical charges.
A dust layer of 4 grams per square meter can decrease solar power conversion by 40 percent, says Malay Mazumder, a research professor in Boston University’s Department of Electrical and Computer Engineering. To put this in perspective, dust deposition in Arizona is about 17 grams per square meter per month, and the situation is worse in many other solar-friendly sites, including the Middle East, Australia and India. Mazumder, who led the study, presented the results Sunday at the 240th National Meeting of the American Chemical Society (ACS).
The electrodynamic transparent screen developed by Mazumder and his colleagues is made by depositing a transparent, electrically sensitive material—indium tin oxide (ITO)—on glass or a clear plastic sheet covering the solar panels. When energized, the electrodes produce a traveling wave of electrostatic and dielectrophoretic forces that lift dust particles from the surface and transport them to the screen’s edges. The researchers found that 90 percent of deposited dust can be removed by the transparent screen in fewer than 60 seconds.

This works in part because many solar panels are positioned at an angle—the raised dust would simply fall off. Whereas solar panels are generally placed in dry, open spaces, the researchers are hoping to make their technique and technology also work to keep raindrops and mud from adhering to solar panel surfaces as well…………
Future generations of dust-proof solar panels are likely to have electrodes embedded in their glass surfaces. These electrodes, like the original filters, would be powered by the solar cell itself, so they would have to operate using very little energy. Sensors would monitor dust levels on the surface of the panel and energize the surface when dust concentration reached a critical level.

Observations: Self-cleaning solar panels could find use in the dusty environs of Arizona, the Middle East or Mars

August 23, 2010 - Posted by Christina Macpherson | 2 WORLD, renewable | climate change, energy efficiency, global warming, renewable energy, renewables, solar