Although for residents of the northern hemisphere winter is approaching, south of the equator it is already getting warmer. And as it gets warmer and dustier there, the likelihood of turning on the air conditioning for a little more comfort increases. The problem, however, is that it consumes a lot of power. That is where a translucent coating developed by engineers at MIT could change. When applied to window panes, the coating reflects 70 per cent of incoming heat from the sun.
According to MIT, air conditioners consume as much as 6 per cent of all electricity produced in the US alone. An amount that accounts for billions of dollars. The MIT research team that developed the coating has calculated that the heat-resistant film can reduce air-conditioning and energy consumption in buildings by 10 per cent when all exterior windows are finished with the coating.
Thanks to the microparticles it contains, the film remains virtually transparent up to 32 °C. Above that temperature, the material undergoes a phase change and takes on the appearance of frosted glass. As a result, less heat is let through to the interior. The project is a collaboration between US-based MIT and the University of Hong Kong on ways to reduce the energy consumption of buildings, especially during the hot summer months.
For every square metre, some 500 watts of heat energy is brought inside as a result of sunlight entering through windows. The team investigated materials that undergo a phase change under the influence of incoming heat. They eventually arrived at a material composed of microparticles of modified poly-2-aminoethyl methacrylate hydrochloride. At temperatures above 29.4°C, the tiny, water-filled spheres shrink to form a fibrous substance. In this state, the film changes from transparent to translucent.
The research team is adjusting the foil formula ever so slightly to see if any progress is made on this. It is also investigating whether the effectiveness can be improved by applying the foil in different ways.
