PartagerUn matériau réfléchissant pour réduire les charges thermiques
Des chercheurs de l'Université de Stanford disent avoir inventé un matériau capable non seulement de réfléchir 97% de la lumière du soleil, réduisant ainsi l'apport de chaleur, mais aussi de rayonner la chaleur à l'extérieur des batiments.
Engineers at Stanford University reported in the journal Nature that they have invented a mirror-like material capable, not only of reflecting 97% of sunlight thus reducing incoming heat, but also radiating heat outside of the buildings in the form of infrared radiation. The result is cooler buildings demanding lower air conditioning use.
Another specificity of this material is that it deflects light from buildings at a precise frequency which allows it to pass through the air without warming the atmosphere. The multilayer material is just 1.8 microns thick, made of seven layers of silicon dioxide and hafnium oxide atop a thin layer of silver.
The layers do not have a uniform thickness, instead the inner structure is tuned to radiate the infrared rays at required wavelengths.
However, two challenges need to be overcome for this technology to be practical: leading the heat from the inside of the building to the coating and constructing panels big enough to cool large buildings. Currently, the prototype is still the size of a small pizza.
Another specificity of this material is that it deflects light from buildings at a precise frequency which allows it to pass through the air without warming the atmosphere. The multilayer material is just 1.8 microns thick, made of seven layers of silicon dioxide and hafnium oxide atop a thin layer of silver.
The layers do not have a uniform thickness, instead the inner structure is tuned to radiate the infrared rays at required wavelengths.
However, two challenges need to be overcome for this technology to be practical: leading the heat from the inside of the building to the coating and constructing panels big enough to cool large buildings. Currently, the prototype is still the size of a small pizza.