Plastic can be cool..
Inspired by the urgent need to reduce the worlds energy consumption researchers at the Swiss Federal Institute of Technology in Zurich, led by Aline Rotzetter, have developed a special polymer mat that soaks up water in the rain and “sweats” when it gets warm. The evaporating water works to cool the house, eliminating a lot of the work of an air conditioner and could save homeowners 60 per cent in air conditioning costs in the process.
Made with PNIPAM that soaks up water the mats cooling mechanism is designed to kick in automatically once temperatures reach 32 degrees Celsius when the material switches from wanting to absorb water to wanting to repel it. The mat squeezes out its stored water. Sweating the way humans and other mammals do and exuding drops of water the mat wicks away heat as the droplets evaporate cooling the roof.
Currently only tested on small model houses the team invite other scientists to explore the application of this patent free technology onto real roofs. Which would need to include testing the mats in the cold and how they might react to being frozen for example. All being well the mats could be very useful for people living in rainy, tropical locations.
Credit: Aline Rotzetter / Advanced Materials Volume 24, Issue 39, pages 53525356, October 9, 2012