Upping the heat
For some time, there has been great interest within the renewable world in finding a low-cost effective system for collecting solar heat at higher temperature levels needed for both domestic and industrial applications. US researchers may have come up with a solution. A new material has been developed sparking hopes it will become the next-gen of solar heat technology. The foam-like material — so translucent as to be practically invisible — generates far higher temperatures than current solar collectors, producing heat beyond 200°C. Made mostly from silica and air, the aerogel easily absorbs 95% of sunlight without allowing the heat to escape.
In tests conducted at the Massachusetts Institute of Technology (MIT), a rooftop device (pictured above) consisting of a heat-absorbing material covered with a layer of the new aerogel was able to maintain a temperature of 220°C — impressive results when you take in to account it was during the middle of winter when the outside temperature was below zero. By comparison, simple, flat rooftop solar panels used for domestic hot water produce temperatures of around 80°C. The aerogel, says MIT researcher Lin Zhao, creates “a greenhouse effect”. “The material we use to increase the temperature acts like the Earth’s atmosphere does to provide insulation, but this is an extreme example of it.”