Color-changing roof tiles

Color-changing roof tiles absorb heat in winter, reflect it in summer

A team of recent MIT graduates has developed roof tiles that change color based on the temperature. The tiles become white when it's hot, allowing them to reflect away most of the sun's heat. When it's cold they turn black and absorb heat just when it's needed.

The team's lab measurements show that in their white state, the tiles reflect about 80 percent of the sunlight falling on them, while when black they reflect only about 30 percent. That means in their white state, they could save as much as 20 percent of present cooling costs, according to recent studies. Savings from the black state in winter have yet to be quantified.

The team, which the students call Thermeleon (rhymes with chameleon, because of its color-changing property), was one of the competitors in this year's Making and Designing Materials Engineering Contest (MADMEC). Nick Orf PhD ’09, a member of the Thermeleon team, explains that he and his teammates originally tried to develop a color-shifting roof tile using a system of mixed fluids, one dark and one light, whose density would change with temperature: the dark substance would float to the top when it was cold, and white would float when it was hot. But the system proved too complicated, and instead they hit on a simpler, less expensive method.
Now, they use a common commercial polymer (in one version, one that is commonly used in hair gels) in a water solution. That solution is encapsulated — between layers of glass and plastic in their original prototype, and between flexible plastic layers in their latest version — with a dark layer at the back.

When the temperature is below a certain level (which they can choose by varying the exact formulation), the polymer stays dissolved, and the black backing shows through, absorbing the sun's heat. But when the temperature climbs, the polymer condenses to form tiny droplets, whose small sizes scatter light and thus produce a white surface, reflecting the sun's heat.
Read more at: http://www.physorg.com/news174209373.html

Out-door tile which purifies air

Air Purifying Tile
Oxygena is like no other tile, the only one which contains titanium dioxide, a precious element which reacts totally naturally to gas pollutants and degrades them, leaving them totally innocuous. The Oxygena line of floor tiles from Italian firm Gambarelli eliminates contaminating gases through its surface. Titanium dioxide reacts to and eliminates polluting gases thus rendering them harmless. When solar rays hit the surface of the tiles, titanium dioxide (thanks to its photo catalytic properties) produces active oxygen, which then oxidizes polluting gases. The gases are transformed into nitrate ions which, combined with water or other elements, become eco-efficient.

Oxygena was created for outdoor use (buildings, balconies, walkways) but can also be laid internally in baths and kitchens and rooms in general. Product ranges have been produced specially for town and city councils for building piazzas, pavements, roundabouts, hospitals, schools and airports.

OXYGENA HAS ALREADY RECEIVED FOUR MAJOR MUNICIPALITY OF TAVERNELLE IN THE PROVINCE OF FLORENCE HAS BUILT THREE ROUNDABOUTS WHICH WILL CONTRIBUTE TO ELIMINATING THE POLLUTION CAUSED BY VEHICLE TRAFFIC. A PUBLIC SWIMMING A SCHOOL IN THE TOWN OF CHIASSO ALSO “VERONICA VERDE” SHOP GROUP, THAT WILL LAY OXYGENA IN ALL ITS SELLING POINTS, ARE THE MORE RECENT WORKS.


To read more click: http://www.gambarelli.it/catalogue/pdf/Catalogo_Tecnico_Oxygena.pdf