American scientists have developed a paint that is significantly “whiter than the whitest color available today”. Tests by Purdue University researchers on their “ultra white” paint showed that it reflected more than 98% of sunlight. According to scientists, this could help save energy and combat climate change. Painting “cool roofs” white is an energy-saving approach that is already being implemented in some large cities. Commercially available white paints reflect between 80% and 90% of sunlight, according to lead researcher Professor Xiulin Ruan of Purdue, West Lafayette, Indiana. “It’s a big deal, since every 1% reflectance transforms to 10 watts per square meter less solar heat,” he said. We estimate you can get 10 kilowatts of cooling capacity to cover approximately 1,000 square feet of ceiling space with our paint. It’s more powerful than the central air conditioners used by most households, “he said. “Cool “white roofs are considered a light urban climate. In the United States, New York recently coated more than 10 million square feet of white roofs.The state of California has already updated building codes to encourage cool roofs. This has the added benefit of using less water for urban irrigation. “We did a very rough calculation,” said Professor Ruan. All we need to do is paint 1% of the earth’s surface this paint, perhaps an area where people don’t live, that is covered in stones and that could help fight the climate change trend. “The new paint contains a compound called barium sulfate, which is also used to make photo paper and cosmetics. “We are using a very high concentration of the composite particles,” explained Professor Ruan. “And we use a lot of different particle sizes because sunlight has different colors at different wavelengths”.
