By Nick Gilbert
A new Aerogel-based plaster was jointly developed by Empa and Fixit AG. This novel plaster delivers two-fold insulation than the existing insulating renders. The product will be brought to the market next year.
This small timber framed house at Empa campus is used for weathering-tests. Dozens of sensors are installed in the test walls and their readings indicate how well the insulation is working. Picture: Empa
Switzerland possesses almost 1-1/2 million old buildings that consume more energy. The Federal Office of Energy states that each year 3 million m3 of natural gas and 4.5 million tons of light fuel oil are being imported, among which 43% is consumed for heating, increasing the need for insulating the buildings. Rendering is capable of maintaining the aesthetic features of old house.
Thomas Stahl and his coworker Severin Hartmeier from Fixit’s central laboratory focused on promoting the insulating properties of render to a higher level, and to develop a render with insulation similar to a polystyrene board. Laboratory testing was successfully completed on the resulting product, its initial trials on buildings commenced in July 2012. The new insulating render will enter the markets by 2013.
At Empa labs, Stahl and his colleagues developed the render made up of aerogel (5% silica and 95% air). It was used in earlier days for insulating space suits, and has been recognized as "best insulator" and "lightest solid" in the Guinness Book of Records.
The aerogel globules are extremely light and weightless. One can hold it between thumb and forefinger, even a slight pressure by the finger can grind it into fine powder. However, the researchers succeeded in mixing the powder with water and applying the render by hand, which resulted in positive outcome.
After prolonged investigations, the researchers at Empa and Fixit have come up with a solution to make the render "machine-compatible”.
The samples of the aerogel render showed heat conductivity below 30 mW/(mK). By bringing the innovation to markets, Swiss proprietors can have high fuel efficiency in their buildings.