New rooftop material may cool buildings without electricity


Yes, the weather has been nasty in New York and points north, with sleet and snow over the weekend following Friday’s blizzard. Snowfall rates maxed out at up to 2 inches per hour in places like Pennsylvania, New York, New Jersey and north into New England. But weather patterns start to change on Tuesday with highs edging into the 40s in New York. The forecast for next Saturday, in fact, is for a high of 45 under mostly sunny skies. The forecast high in Philadelphia is 51; 55 in Washington. NOAA’s Climate Prediction Center is calling for above normal temperatures in most of the U.S. east of the Rockies and continuing into early March. It looks like Florida temperatures will remain mostly above average for the rest of the month, with the occasional cold front that does little more than return temps to near seasonal normals for a couple of days, according to the National Weather Service. (Image credit: NWS-Key West)


Eat your heart out, FPL.

Researchers may have figured out a way to keep your house cool without using electricity to blow cool air into your house, by letting nature do the job via radiational cooling.

That’s the phenomenon that pulls heat away from the ground and from structures, mostly at night, since heat rises. But scientists have come up with a way to trigger radiational heat loss during the day, too, even when the sun is shining.

It’s accomplished with a new kind of material that can be put on roofs, cooling objects under it by reflecting solar energy back into space and — at the same time — allowing structures to shed heat in the form of infrared thermal radiation.

The material, slightly thicker than ordinary aluminum foil and manufactured on rolls, was developed by researchers at the University of Colorado at Boulder and the University of Wyoming.

“Just 10 to 20 square meters of this material on the rooftop could nicely cool down a single-family house in summer,” said study co-author Gang Tan, an associate professor in the University of Wyoming’s Department of Civil and Architectural Engineering.

Tan and colleagues have applied for a patent on the material and plan to create a “cooling farm” prototype this year in Boulder.

In addition to direct commercial and residential applications, the material can also make solar panels perform more efficiently and can extend their life by preventing overheating that hampers their ability to convert heat into electricity.

“The key advantage of this technology is that it works 24/7 with no electricity or water usage,” said Ronggui Yang, a professor of mechanical engineering at UC. “We’re excited about the opportunity to explore potential uses in the power industry, aerospace, agriculture and more.”

The development of the new material was announced Thursday in the journal Science.


Author: jnelander

Freelance writer and editor

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