Yi Zheng, an associate professor of mechanical and industrial engineering at Northeastern University in Boston, has created a sustainable material that can be used to make buildings or other objects keep cool without relying on conventional cooling systems.
Zheng envisions this “cooling paper” covering the roofs of buildings. The light-colored material reflects hot solar rays away from the building and also sucks heat out of the interior. It is actually made of paper, and the porous micro-structure of the natural fibers inside absorbs the indoor warmth and re-emits it away from the building.
Zheng, who studies nanomaterials, got the idea when he looked at a bucket full of used printing paper. He recalls thinking to himself, ‘How could we simply transform that waste material into some functional energy material, composite materials?’
Using a kitchen blender, Zheng made a pulp out of paper waste and mixed it with the material that makes up Teflon. Then he formed it into water-repelling “cooling paper” that could coat homes. Zheng and his colleagues found that the cooling paper can reduce a room’s temperature by as much as 10 degrees Fahrenheit (6 C).
The material can be used, exposed to solar radiation, weather, and varying temperatures, then reduced to a pulp (again) and reformed without losing any of its cooling properties. “I was surprised when I obtained the same result,” Zheng says. “We thought there would be maybe 10 percent, 20 percent of loss, but no.”
The process for creating and testing the new material was described in a paper published last month and Zheng was awarded a National Science Foundation CAREER Award grant for his research.
Zheng hopes that his work will help save energy and combat climate change. “The starting point is to reduce the use of carbon-based materials and also to reduce global warming,” Zheng says.
You can read the original article at news.northeastern.edu