Purdue University engineers have created white paint that can keep surfaces up to 18 degrees Fahrenheit cooler than their ambient surroundings – almost like a refrigerator does, but without consuming energy. Commercial “heat rejecting paints” currently on the market reflect only 80%-90% of sunlight and cannot achieve temperatures below their surroundings. The white paint that Purdue researchers created reflects 95.5% sunlight and efficiently radiates infrared heat.
Earth’s surface would actually get cooler with this technology if the paint were applied to a variety of surfaces including roads, rooftops and cars all over the world. The paint would not only send heat away from a surface, but also away from Earth into deep space.
In a paper published Wednesday (Oct. 21) in the journal Cell Reports Physical Science, the researchers show that compared with commercial white paint, the paint that they developed can maintain a lower temperature under direct sunlight and reflect more ultraviolet rays.
This paint would be both cheaper to produce than its commercial alternative and could save about a dollar per day that would have been spent on air conditioning for a one-story house of approximately 1,076 square feet. It would take about ten gallons to paint a 1,076 square foot house.
The world makes about ten billion gallons (55 million tons of paint a year). Saving a dollar a day would mean a payback for ten gallons of paint in 6-12 months.
If paint production was doubled and the new production was used for this superwhite paint then 100,000 square kilometers could be painted every year.
Paint using CaCO3 fillers with high concentration and broad particle size
The paint shows a high solar reflectance of 95.5% and sky window emissivity of 0.94
Field test shows over 37 W/m2 cooling power and over 1.7°C below ambient at noon
Commercial-like paint offers a high standard figure of merit of 0.49
The new paint is compatible with regular commercial paint fabrication processes.
SOURCES Purdue University, Cell Reports Physical Science
Written By Brian Wang, Nextbigfuture.com
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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