A research team led by UCLA materials scientists has demonstrated ways to make super white paint that reflects as much as 98% of incoming heat from the sun.
A research team led by UCLA materials scientists has demonstrated ways to make super white paint that reflects as much as 98% of incoming heat from the sun. The advance shows practical pathways for designing paints that, if used on rooftops and other parts of a building, could significantly reduce cooling costs, beyond what standard white ‘cool-roof’ paints can achieve.
The findings, published online in Joule, are a major and practical step towards keeping buildings cooler by passive daytime radiative cooling – a spontaneous process in which a surface reflects sunlight and radiates heat into space, cooling down to potentially sub-ambient temperatures. This can lower indoor temperatures and help cut down on air conditioner use and associated carbon dioxide emissions.
“When you wear a white T-shirt on a hot sunny day, you feel cooler than if you wore one that’s darker in color – that’s because the white shirt reflects more sunlight and it’s the same concept for buildings,” said Aaswath Raman, an assistant professor of materials science and engineering at UCLA Samueli School of Engineering, and the principal investigator on the study. “A roof painted white will be cooler inside than one in a darker shade. But those paints also do something else: they reject heat at infrared wavelengths, which we humans cannot see with our eyes. This could allow buildings to cool down even more by radiative cooling.”
Read more at University Of California - Los Angeles
Photo: Under noontime sunlight, superwhite paints (labeled EL1 and EL3) developed by the researchers remain significantly cooler than traditional white paints (right corner, labeled EL2), which could lead to higher energy savings in buildings. Photo credit: Jyotirmoy Mandal.
