“Unlikea typical photovoltaic system, which converts sunlight to electricity, a solar thermal roof uses solar energy to heat air,” said Steve Rebetsky, ALC Directorate of Public Works mechanical engineer, who is managing the construction project.The construction of theroof relies on standardmethodswith a few modifications.
A dark-colored standing-seam metal roofis constructed over theexisting roof, but a flexible radiant barrier is installed under the support structure,creating a gap where the air isheated by the sun to approximately 40 degrees Fahrenheit above the ambient air temperatures.
A control system and circulating fans then pumpthe airto the various mechanical systems and interior spaces of the building. The heated air is then used within the building to reduce the required heating load.
Solar heated air to be used to heat water for domestic use and for heating, ventilation, and air conditioning systems
During the winter, the system will pre-heat fresh outside air that is used to maintain proper building ventilation. Thesolar heated air will be used to heat water fordomestic use and for the heating, ventilation, and air conditioning systems.
It willalso directly heat the main mechanical room andboiler combustion air, resulting in increased boiler efficiency. Duringthe summer, when the sun is most intense, the radiant barrier will prevent morethan 90percentof the heat from entering the building and at the same time, since heating requirementsare at their lowest, exhaust any excessheated air to the atmosphere.
The 601roof isone of the first such solar thermal roof projects to beconstructed foran office building in the United States, according to the project manager with AmericanSolar Inc., thecompanyinstalling the system.
“With the successful completionof thisprojectwe hopeto further the Garrison’s use of renewable resources and, in addition to solar thermal roofs, expand toother renewableenergy projectsutilizing photovoltaic,solar water heating andsolar lighting,” said Ken Noppenberger,ALC director ofpublic works. “This will help us continue to not only meet DoD energy goals, but also conserve electricity, natural gas, oil, etc.”