Scientists at the Massachusetts Institute of Technology (MIT) have recently invented a new smart roofing tile called “Thermeleon” (rhymes with “chameleon”), which is thermochromic – in other words, when it is exposed to heat it changes color from black to white, and vice-versa.
Thermeleon works by sandwiching common polymers between several flexible plastic layers. When it is cold outside, the polymer solution stays dissolved and the black rear-face shows through to absorb the natural heat. When it heats up outside, the polymer solution condenses to form light-scattering droplets (in other words, it turns white), to reflect the heat.
We now know that a white roof reflects up to 80% of the sunlight, keeping the interior of the building beneath the roof much cooler. This can result in a 20% reduction in summer air conditioning costs. But during the winter months when you would rather your roof capture as much heat as possible from the sun, the black coloring has the reverse effect - these tiles scatter only 30% of incoming solar radiation, thereby helping to keep the building beneath the roof warmer (reducing heating costs).
The team at MIT is now working on micro-encapsulating the chemicals to create a commercially-viable paintable or spray-on roof coating. If they can figure out how to produce this roof coating at a favorable price and proves to be durable enough for the extreme summer months in regions like the desert southwest, this could very well be a sneak peek at the future of cool roofing.
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