A new self-cooling roofing material under development at the University of Technology Sydney is able to remain cooler than a conventional white coloured roof by a staggering 11 degrees C when exposed to maximum summer temperatures. Early studies seem to suggest this new material could have great potential for use in urban centres, particularly in cities that rely heavily on air conditioning.
The material is made from layers of specialized plastics on top of silver. The material reflects light so well that even on the sunniest days, in only absorbs three percent of the sunlight that strikes its surface. “The coating keeps the roof cool by reflecting almost all of the incoming solar radiation,” says Angus Gentle, a researcher at the University who developed the material in collaboration with physics professor Geoff Smith. “A vast majority of this emitted radiation goes directly into space without being absorbed by the atmosphere,” he continues. By comparion, a standard roof absorbs as much as 90% of light, while the best ‘cool’ roofs only reflect around 70% to 85% of the sun’s rays.
So far, the material’s performance appears to be unaffected by urban pollution, making it ideal for use in keeping city temperatures down in the summer and negating the need for individual air conditioning systems. And while to date the material is still only available from the lab, it is made with commonly available and relatively affordable materials. Impressive!