by AF 0330 g3 — April 2, 2010—Scientists reported the development of a “smart” roof coating, made from waste cooking oil from fast food restaurants, that can “read” a thermometer. The coating automatically switches roles, reflecting or transmitting solar heat, when the outdoor temperature crosses a preset point that can be tuned to the local climate. They described the coating at the 239th National Meeting of the American Chemical Society (ACS) in San Francisco.
Roofs coated with the material would reflect scorching summer sunlight and reduce sticker-shock air-conditioning bills. When chilly weather sets in, the coating would change roles and transmit heat to help warm the interior.
“This is one of the most innovative and practical roofing coating materials developed to date,” said Ben Wen, Ph.D., leader of the research project and a vice president of United Environment & Energy LLC. “This bio-based intelligent roof coating, compared with a traditional cool roof, could reduce both heating and cooling costs as it responds to the external environment. It will help save fuel and electricity and reduce emissions of volatile organic compounds from petroleum-based roofing products. In addition, it will provide a new use for millions of gallons of waste oil after it is used to cook french fries and chicken nuggets.”
Scientists already have evidence that “white roofs” — roofs that are painted white to reflect solar heat and help cool buildings during peak summer weather — could significantly reduce global warming by lowering fuel consumption. However, white roofs can have a wintertime heating penalty because they reflect solar heat that would help warm the building.
The new coating may sidestep this quandry. Tests on coated asphalt shingles showed that it could reduce roof temperatures by about 50 to 80 percent in warm weather. In cooler weather, the coating could increase roof temperatures up to 80 percent compared with the traditional cool roof. By changing the coating’s composition, Wen and colleagues can tune the substance, so that it changes from reflective to transmitive at a specific environmental temperature.
Wen’s research is funded by the Department of Energy (DOE). His collaborators in this study include Peng Zhang and Marianne Meyers, also of United Environment & Energy LLC. For more information visit United Environment & Energy.
