Student of the Polytechnic University of Turin, Manuel Ibba has created a roof tile concept that changes colour when the temperature reaches 20o C. Titled X-Tile, the roof tile possesses the ability to reflect light and heat by turning white above 20°C and absorb it by turning black below 20°C, subsequently cooling or heating a home.
Ever since his childhood, Ibba has wanted to sustainably help save the planet. “For this reason, I chose a university course oriented towards sustainability in which I was able to design different solutions for energy saving,” he adds. He realised that electrical air conditioners add immensely to the rising climate change. He came across the news on preserving glaciers by covering them with huge white geotextile blankets to reflect the light and heat to prevent them from melting. That’s how he came up with the idea for his roof tile. However, the idea only solidified from observing a mug that turned from black to white when poured with hot drinks inside. He applied this concept to a ceramic tile that can be designed to isolate and dissipate heat.
Most of the tiles are made of terracotta, which absorbs heat. White ceramic can also reflect sunlight that would otherwise heat the roof and the house. On the other hand, in winter it would be ideal for it to be black to absorb light and transform it into heat.
“At the beginning, the concept involved the adoption of tiles with moving parts. They were coloured on one side white and on the other side they were black. As the temperature changes, it would have been necessary to find a mechanical way to rotate the tile surface. However, this would have implied some complex systems of electric, or worse, manual movement,” Ibba tells us. It was important for Ibba to find a way to automate the colour change process without manual interventions and consuming energy. He considered using e-ink (electronic ink) like the one used by e-readers. Its tiny titanium bioxide spheres allow the colour to change from white to black just by using a small amount of energy that is obtained using a small photovoltaic panel. However, this turned out to be an expensive solution for an entire roof.
A thermo-chromatic paint, often used on commercial rugs, had been eventually picked to achieve the purpose. Ibba characterized the shape of the tile, which is inspired by a computer heat sink, in such a manner that it would rapidly disperse heat.
Upon firing the clay, Ibba applied a layer of black thermo-chromatic paint and a layer of white paint. Above 20o C, the black layer becomes transparent, thereby allowing light to reflect on the underlying white layer. This paint is permanently applied to the tile with transparent glossy enamel. The paint becomes stable after firing it for the second time. Ibba created the tile design in such a manner that it isolates cold/heat with an internal ventilated chamber dissipating heat with some slats.
Way to the future
X-Tile allows buildings to self-regulate temperature by changing the light absorption and reflection properties of the roof. Ibba’s X-Tile project aims at improving the energy sustainability of the houses with three different solutions in the same product. Ibba suggests that if X-Tile is adopted by everyone, it would contribute a lot to reducing the global CO2 emissions from heating and cooling buildings and making warmer cities more habitable.
Going forward, Ibba is in plans to verify the effective duration of the thermo-chromatic properties of the tiles over the years and to find another permanent fixing for his paints crisis which would last for years without changing its characteristics. Additionally, he is in the process to reduce the production costs which are higher than normal tiles due to the double firing and special paint.
Photographs: Manuel Ibba; courtesy: The James Dyson Award