What works for thermos flasks can also be used for thermally insulating buildings: insulation by means of a vacuum. For this purpose, panels made of compressed silica powder, which is an extremely porous material, are enclosed in a largely gas- and water vapour-tight envelope made of special high-barrier films or stainless steel and evacuated. The thermal insulation provided by these vacuum insulation panels (VIPs) is five to ten times that achieved by conventional insulation systems. This means that vacuum insulation requires a correspondingly lower thickness of insulation material to achieve the same insulating effect, which is highly beneficial when there are space constraints or high thermal insulation requirements.

Although VIPs offer new, highly efficient solutions in building, they also require new forms of collaboration and planning. In contrast to conventional insulation technology where the material can be cut to size on site, with these insulation elements it already needs to be determined whether standard sizes can be used and the sizes that are required for custommade elements during the design phase. Furthermore, the elements are, from a mechanical point of view, relatively fragile: if the envelope is damaged, the vacuum can ‘escape’ and the thermal insulation effect is reduced.

In recent years, vacuum insulation systems for the construction industry have been tried, tested and further developed in various research projects. In 2008, the first construction products using VIP systems were granted building regulations approval in Germany. In ViBau, a research area forming part of the energyoptimised construction (EnOB) research initiative run by the German Federal Ministry of Economics and Technology, various research institutes and companies are working on further improvements to the technology. The focus is currently on quality checks and quality assurance as well as on monitoring commercial applications used in building practice.

Parallel to this, research is also being conducted on glazing systems using a vacuum in the space between the panes, whereby it is essential to have a gas-tight edge seal. In order to be able to bear the pressure load of the ambient atmosphere, suitable spacers also need to be found for the inter-pane cavity. The development of a highly efficient window frame completes the system. This Themeninfo brochure explains the principles behind this new thermal insulation technology, its potential applications and its unique features. Examples from practice demonstrate possible applications in new-build schemes and refurbishments.