Researchers at Purdue University have developed a new ultra-white paint that reflects 98.1 percent of sunlight and can keep surfaces up to 19 degrees Fahrenheit cooler than their ambient surroundings.
This paint only absorbs 1.9 percent of the sunlight, whereas commercial paint absorbs 10 to 20 percent of sunlight.
The paint is a marked improvement from current heat-rejecting paints on the market. When struck by the sun’s rays, surfaces covered in today’s available white paints get warmer, not cooler. At best, these heat-combating paints can reflect 80 to 90 percent of sunlight.
The new ultra-white paint, which the researchers say is the coolest on record, reflects nearly all of the sun’s rays and sends infrared heat away from the surface, providing an average cooling power of 113 watts per square meter.
It is made of barium sulfate, a known UV-reflecting compound that was already being used in cosmetics, reflective photo paper, oil paints, x-ray examinations and other applications.
If painted onto the roof of a 1,000-square-foot home, that translates to a cooling power of 10 kilowatts, which is more powerful than most residential central air conditioners.
Using statistical modeling, the researchers estimated that their ultra-white paint could reduce air conditioning use by up to 70 percent in hot cities.
Reference- Journal ACS Applied Materials & Interfaces, Purdue Mechanical Engineering Dept. Media Outreach, The Hindu