Gallery: Study Discovers That Solar Panels Have a Cooling Effect on Bui...


It turns out that solar panels can do more than provide you with renewable energy – they can significantly cut down the power needed to heat and cool your building as well. In a study recently released in the journal Solar Energy, an engineering team at UC San Diego found that the presence of solar panels on rooftops keeps buildings an average of 5 degrees Fahrenheit cooler during the day and keeps heat in during the nighttime, which could save cash on heating costs in the winter.

The team of researchers, led by Jan Kleissl, a professor of environmental engineering at the UC San Diego Jacobs School of Engineering, discovered that the amount of money saved on heating and cooling costs could add up to a 5% savings on the total cost of the solar panels if factored in as energy saved. The team used thermal infrared cameras to capture temperature data from the rooftop of the Powell Structural Systems Laboratory at the Jacobs School of Engineering which has been outfitted with tilted solar panels and solar panels flush with the roof, while also maintaining some exposed areas.

Instead of the sun beating directly onto the roof and heat seeping through the roofing material and into the building, the solar panels absorb that direct sunlight, turn it into energy and divert the heat from the building. The panels, especially the tilted kind, create wind tunnels where heat is swept away from the building as it moves between the panels and the rooftop. The team found that solar panels could reduce heat reaching the rooftop by as much as 38% and the more efficient solar panels had higher heat redirection rates. “There are more efficient ways to passively cool buildings, such as reflective roof membranes,” said Kleissl. “But, if you are considering installing solar photovoltaic, depending on your roof thermal properties, you can expect a large reduction in the amount of energy you use to cool your residence or business.”

Via PhysOrg


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  1. Rapier July 19, 2011 at 5:39 pm

    It’s a simple energy balance equation: Absorbtivity plus reflectance plus transmission equals 100%. Good solar panels take 20% off the top by converting it to electricity. So, they should cause 80% as much radiant heat gain as a roof tile the same color.

    Elevating them over the roof acts as a heat shield, cutting radiant heat gain by 50% or more, for about a 60% reduction in solar heat gain on the part of the roof they cover.

  2. Buildingwell July 19, 2011 at 4:40 pm

    The results of this study are very promising. This may help to encourage additional building owners to consider solar installations with the added benefit of reducing heating/cooling needs. There are of course many considerations to think about when installing solar for your building:

  3. sempergreen July 19, 2011 at 3:47 pm

    If you combine solar panels with a green roof you save even more money.
    A green roof will extend the life of the waterproofing membrane that the solar panels are installed on top of and will keep the roof even cooler.
    The biggest cost of solar is not the panels themselves but theinitial installation and take-down of the system in case the waterproofing needs to be replaced. (roughly after 20 years)
    Extend the lifespan of the membrane and save big $$$. Just my 2 cents..

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