Keeping solar panels in their place
By Nicole Laidler | June 20, 2013
Solar panels are popping up on rooftops and in fields across North America, providing cleaner power for an energy-hungry world. But manufacturers are often working in the dark during the installation process as building codes remain largely silent about best practices, having yet to catch up with the new technology.
That can leave panels, people, and property vulnerable during inclement weather.
Western Civil and Environmental Engineering professor and BLWTL Director, Greg Kopp, is helping to reduce the risk. He’s been working with industry partners to develop code for wind loads on solar panels since 2007.
Although we’ve all seen small solar arrays springing up in farmer’s fields, Kopp says flat-roofed industrial buildings are efficient places for solar panel installation.“You can have a sea of panels worth tens of millions of dollars on one roof,” he explains.
That adds extra weight to an existing structure and may change how the wind acts on the building. “You need to know about the loads to make sure the buildings remain safe and that the panels don’t go flying off in a wind storm,” says Kopp.
The trick is to strike the right balance between keeping the solar panels in place without adding too much weight to the roof. “If you mechanically fasten the array into the roof structure you are putting holes through the roof cover and it may leak,” he explains. “Nobody wants that. They want arrays that sit on the roof and which are held under their own weight. That’s the challenge.”
California’s SunLink Corporation, a leader in solar roof and ground-mount racking systems, was the first company to approach Kopp for help. They remain one of the Boundary Layer Wind Tunnel Laboratory’s largest solar industry partners.
“SunLink were very early in the game of doing wind tunnel studies and wanted to work with a well-known wind lab,” says Kopp. “We are one of the oldest wind engineering labs in the world and we have a lot of experience, which is important.”
Kopp has also conducted wind load studies on residential solar panels. Unlike their industrial counterparts these are usually mechanically fastened to an angled roof, presenting a different set of challenges.
Data generated by testing scale models of various solar panel arrays on a variety of building shapes in Western’s BLWTL has already been used to make recommendations that Kopp calls “simple to use” and “accessibly conservative.”
“We've developed recommendations, with others, that are currently being considered for acceptance across the United States," says Kopp. “If you put solar panels on a roof, there will now be guidelines on how to do it.” Changes to the National Building Code of Canada are also in the works.“Solar installations are going in all around the world, which I think is a very good thing,” notes Kopp. And thanks to his work at the BLWTL they will be more likely to stay put when the wind starts to blow.