Greening an American Institution
In the spring of 2010, American University (AU) in Washington, DC announced its goal to neutralize greenhouse gas emissions and become a carbonneutral campus by 2020 by reducing consumption, producing renewable energy, investing in green power and developing sustainable carbon offsets.
“As an institution of higher education in the nation’s capital, it’s incumbent upon us to lead climate change mitigation strategies,” says Sustainability Director Chris O’Brien. “We’re training the next generation of leaders, and it’s critical that our students understand the problems and be a part of the solution.”
To fulfill its renewable energy commitment, the university plans to use both wind and solar power. To this end, in May 2011, AU embarked on what would be the largest solar electricity project in Washington, DC; retaining Standard Solar of Rockville, MD to install more than 2000 solar panels on buildings throughout the campus including Bender Library, Mary Graydon Center, Washington College of Law, 3201 New Mexico Ave., 4200 Wisconsin Ave., Greenberg Theater, and Katzen Art Center. Standard Solar selected SunLink Corporation to design and supply custom mounting solutions for each building.
The six roofs presented solar installation challenges in the form of skylights, ventilation systems and other roof obstructions making it difficult to determine panel locations due to limited space availability and shading issues. After several design iterations and various panel layouts for each building, SunLink finalized six commercial roof mount solar designs that satisfied both Standard Solar and the university.
“Sunlink’s ballasted roof mount system is one of the most versatile and adaptive mounting systems available,” says Mike Sloan, Standard Solar’s Vice President of Commercial. “With most other racking systems there would be no available solution to resolve some of the structural issues we encountered. We would have had to cut down the size of the arrays, avoid certain areas of the rooftops, or possibly even eliminate entire sites.”
With final layouts optimized for both module exposure and efficiency, SunLink’s engineers stepped in to develop a roof-friendly and safe mounting solution. As with any rooftop solar project, it was important to minimize the number of penetrations on the roofs in order to preserve the integrity of the buildings and minimize the amount of roof alterations. However, because three of the buildings fell outside of the “low-rise” building category (having roof heights of more than 60’), fully ballasted systems were very challenging to design. SunLink successfully designed four of the six systems as fully ballasted and without any roof penetrations. The remaining two roofs consisted of hybrid systems, which relied mostly on ballast, but also employed limited connections to anchor the mounting system to the roof in certain locations.
Of course, building owners tend not to want to put holes in their roofs if they can avoid it. However, with the additional weight of the solar system and wind, snow and earthquake loads, sometimes a connected system is best for the building and for safety. SunLink’s engineers find solutions that are as roof-friendly as possible while also being as safe as possible. The company invests a great deal in R&D to understand wind, seismic activity and other environmental factors to help them do so.
Sloan emphasizes, “SunLink’s solid engineering support enabled us to get through Washington, DC’s permitting process quickly and without hang-ups.”
Due to the densely populated, high traffic metropolitan location of American University, delivering over 500 kilowatts of aluminum solar panel mounting hardware to six different buildings required careful planning and communication.
Because the material would arrive on several large trucks and require heavy duty machinery to unload, SunLink project managers arranged for delivery to be completed within a very specific delivery window so as to not disturb campus traffic. In addition, to facilitate sorting and distributing the material among the six buildings, all components were specifically labeled to show exactly what material belonged on which roof.
“SunLink helped us provide an operationally low impact installation,” Sloan adds. “Crane lifts and installation activities did not interrupt AU classes, which was crucial for the university.”
Adapting to Changing Conditions
Once on the roof, unforeseen installation challenges inevitably arise. When Standard Solar’s Structural Engineer of Record (SEOR) discovered that one particular section of the 4200 Wisconsin Ave. theater building roof had more stringent power limitations than originally anticipated, it was necessary to remove several panels from this roof and add them instead to the installation on the New Mexico Building.
“We support our customers through the entire installation process and help them respond to any challenges that arise,” says Tilley. “In this case, our system designers altered the layout design, the engineers revised the engineering calculations and installation recommendations, and project managers helped locate and redistribute material that had been previously separated and dispersed throughout the campus. As a result, Standard Solar was able to successfully install the systems per American University’s requirements.”
A Brighter Future
Universities have a unique opportunity to use their rooftops to generate the electricity they need, while at the same time helping to educate the next generation about the viability of solar power. We hope that other universities will see the American University project and realize the potential of rooftop solar to meet their own renewable energy goals.