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Northland College students install solar panels on library

May 11, 2009

There was no shortage of sun on the roof of the Dexter Library Thursday as 13 Northland College students enrolled in Sustainable Living: Photovoltaics hoisted the first of 38 solar panels into place. Students in the month-long course are not only gaining hands-on experience by bolting the framework together and mounting the panels, they are also learning how to determine the appropriate system for the site. Scott Grinnell, associate professor of physics, is teaching the month-long course in May with help from Conservation Technologies, a Duluth-based company assisting with the installation.

The new photovoltaic system, which employs bifacial panels, can capture direct sunlight and light reflected by the building’s white roof. It is expected to produce 14 kilowatts of power, approximately the amount used by the library’s geothermal heating and cooling system. The result will be a building that is heating and cooling neutral, an impressive feat in Northern Wisconsin.

“The students in this class go through all the procedures of assessing a site to figure out the appropriate system for that particular location,” said Grinnell. “With the skills they learn in this course, students could actually go out and get a job as a site assessor, providing information for people interested in sustainable energy systems.” The class begins by conducting a load analysis on a building or residence to determine annual energy consumption. That information is then used to determine the size and type of system that would be required to fill the energy need.

Grinnell led a similar class in May 2008 that installed 12 panels in front of the Northland College President’s House. That solar array was attached to a sun-watt tracking system, a mechanism that automatically moves the panels to follow the sun through the course of the day.

The panels being installed on the library, while much more numerous, are mounted firmly on an aluminum framework, and will not move to track the sun. The students are discovering that this larger, but less technically complex system, is far better suited to its specific location atop the building. The project is expected to pay for itself in energy savings before the 20-year warranty expires, and Grinnell expects the system will remain productive for at least 50 years, losing only 0.5 percent of its output per year.