Researchers at the Ginzton Laboratory at Stanford University have found that coating a roof with a specific inorganic compound mixture could help not only cool buildings without the use of electricity but also release warmth in a way that it would pass through the Earth’s atmosphere, Climate News Network reported.
The research team conducted daytime tests and found that seven layers of hafnium oxide and silicon dioxide on roofs “reflected 97 percent of the sunlight away from the building” and that “the temperatures in the structure below the new material fell 4.9°C” without the use of electricity.
Called photonic radiative cooling, the use of the compound could completely change the lives of those in tropical climates lacking access to electricity and air conditioners, all without adding to the ever increasing effects of climate change.
“These results demonstrate that a tailored, photonic approach can fundamentally enable new technological possibilities for energy efficiency,” wrote researchers. “Further, the cold darkness of the Universe can be used as a renewable thermodynamic resource, even during the hottest hours of the day.”
As Climate News explained, the scientists started with layers of hafnium oxide, which is already used in semiconductors, and silicon dioxide, also known as silica or quartz. They fashioned an “ultrathin film” that acted as a “near-perfect reflector of visible light” and as an “efficient emitter for infrared light.”
And while there are still specifics on how to use the material on a widespread basis to be worked out, the researchers do see this as a possible new way to think about energy efficiency.
“Every object that produces heat has to dump that heat into a heat sink,” said one of the report’s authors, Sanford Professor Shanhui Fan. “What we’ve done is create a way that should allow us to use the coldness of the universe as a heat sink during the day.