Eco-roofs could cool solar panels

Rooftop solar panels lose efficiency at high temperatures, but PSU researchers think they’ve found a solution in eco-roofs.

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A growing number of downtown Portland buildings have solar panels on their roofs, which in summer weather can become 50 to 90 degrees hotter than the surrounding air.

These high temperatures cause the solar panels to lose efficiency, but Portland State University researchers are investigating eco-roofs as a possible solution.

“Photovoltaic panels may benefit from an eco-roof in that an eco-roof creates a cooler environment,” said David Sailor, a PSU professor and director of the Green Building Research Lab. “The panels could operate a little more efficiently. At the same time, vegetation does better in partial shade, so (photovoltaics) could in turn provide that.”

Sailor, PSU chemistry professor Carl Wamser and PSU assistant professor of biology Todd Rosenstiel have installed several test combinations of eco-roofs and solar panels on the roof of Science Building 2 at PSU. Sailor said the project is still in its early stages, and that the researchers have not yet set up equipment to track temperatures and other performance criteria. The eco-roofs will be tracked through an entire growing season.

Read the full report at the Daily Journal of Commerce.