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Thinner Thermal Insulation for Better Energy Savings

In order to lower energy costs, more and more homeowners are investing in insulation facades. But the typical insulation layers on the market have one drawback: they add bulk. The thick outer skin changes the building’s visual appearance and can result in significant follow-up costs – with a need to fit new, deeper window sills and sometimes even roof extensions.

Researchers are now developing films for a material that will insulate homes without much additional structural alteration - vacuum isolation panels (VIPs). The panels are only two centimeters thick and yet perform just as well as a classic 15-centimeter-thick insulation layer made from polyurethane foam. The inner workings of the VIPs are made mostly from pyrogenic silica. A high-tech film holds the material together and makes it air-tight.

Dr. Klaus Noller from the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising, Germany and Professor Gerhard Sextl from the Fraunhofer Institute for Silicate Research ISC in Würzburg, Germany have been involved with the development of VIPs since the very beginning. Now they want to ready the panels for cost-effective mass production. “The key elements are the films: they dictate the quality, life span, and price,” says Noller. “The current production method is time-consuming and expensive: three of the five layers of plastic have to be coated with aluminum and stuck together. This requires seven production steps, which drives the price up.” At present, these expensive VIPs are employed only where a space saving is worth the money such as in high-end refrigerators and freezers.

The new film is easier to produce because it is made up of just two plastic films with three barrier layers - one aluminum-coated plastic film is coated with a micrometer-thin layer of ORMOCER® (an ISC invention) and then coated again with aluminum. ORMOCER®s contain an organic-inorganic hybrid silicon-oxygen polymer matrix, which makes the material exceptionally tight and stable. “That’s what makes it perfect for insulation panels,” says Noller. “Gases and liquids cannot easily penetrate the ORMOCER® layer.” The new insulation films can be fashioned in just five stages. First a film is coated, then the ORMOCER® layer applied, then coated a second time before the barrier film is applied to the sealing film. “The end product is better and cheaper than the insulation films already on the market,” claims Sextl.

(Fraunhofer)