Solar Panel Cleaning

Have you been MISINFORMED about your solar panels' needs to stay clean?

Most PV (photo-voltaic) system salesmen and/or installers say one of the following:

  • "No, you don't ever need to clean solar panels"
  • "Rain will wash your solar panels clean"
  • "Just give them a quick rinse with your garden hose"

The facts relating to those statements are:

  • In the desert where we live, you DO NEED to keep them clean, (see the scientific data below). In other climates it may not be as necessary to clean your solar panels to keep them operating, but if you do clean them they will always operate more efficiently (and that means saving you more money).
  • Does rain wash your windows or your car clean? Not really, and it doesn't do much better of cleaning solar panels. In other parts of the earth, where it rains a lot, it is possible for rain to keep your panels from accumulating dust, just not here, in Tucson, Arizona.
  • Tucson has what we call "hard-water" (full of minerals), so if you rinse your solar panels with your garden hose, it WILL leave hard-water deposits just like you get on the windows, except these will prevent the PV cells from absorbing and converting sunlight into energy. Basically it will kill your solar panels.

Keeping solar panels free from dust

Shawn-Streakless-Window-Solar-Panels
Monday, 23 August 2010
Stuart Gary
ABC

Dr Malay K. Mazumder, of Boston University has presented his latest research at this week's national meeting of the American Chemical Society.

The use of photovoltaic cells as an environmentally safe way to generate electricity has increased by 50% in recent years and some forecasts suggest an annual growth rate of at least 25% into the future, says Mazumder.

Mazumder says such installations are often built in sun-soaked desert areas where dry weather and winds deposit dust on the solar panel surfaces.

"A dust layer of 4 grams per square metre decreases solar power conversion by 40%," he says.

"In Arizona, dust is deposited each month at over 4 times that amount."

Should you spring clean your solar panels?

Google Blog
July 31, 2009

Ever since we assembled a 1.6 MW solar panel installation at our headquarters in Mountain View in 2007, we've been wondering, "Does cleaning the solar panels make them more effective?" We thought it might, but we needed to be sure. So we analyzed the mountains of data that we collect about the energy that these panels produce — after rain, after cleaning and at different times of the year.

We have two different sets of solar panels on our campus — completely flat ones installed on carports, and rooftop ones that are tilted.

Since the carport solar panels have no tilt, rain doesn't do a good job of rinsing off the dirt they collect. (Also, our carports are situated across from a sand field, which doesn't help the situation.) We cleaned these panels for the first time after they had been in operation for 15 months, and their energy output doubled overnight. When we cleaned them again eight months later, their output instantly increased by 36 percent. In fact, we found that cleaning these panels is the #1 way to maximize the energy they produce. As a result, we've added the carport solar panels to our spring cleaning checklist.

Don't bury your investment in the dust and sand of Arizona!

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