By turning white in warmer weather and thus reflecting light, a new breed of roof tiles could save companies energy. In the winter, conversely, the tiles would turn black to absorb heat.
The new tiles were developed by students at MIT.
In their white state, the tiles reflect about 80 percent of the sunlight that hits them, which could help a building reduce cooling costs up to 20 percent, according to MIT News.
When black, the tiles reflect only about 30 percent of the sunlight.
The MIT student team has dubbed the tile the “Thermeleon.”
Here’s how the tiles work: a commercial polymer and water are encapsulated between flexible plastic layers, with a dark layer at the back. When the temperature is below a certain level, the polymer remains dissolved, allowing the black to show through. When the temperature is warm, the polymer “condenses to form tiny droplets, whose small sizes scatter light and thus produce a white surface.”
The next step in the research is converting the idea into a simpler version that could be brushed or spray-painted on a surface.
Energy Secretary Steven Chu has said that turning all the world’s white could reduce GHG emissions in 20 years the same amount that the world produces in a year.