Vacuum insulation panels
Vacuum insulation glass
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Vacuum Insulation Glass: Edge effects

The excellent insulating effect of vacuum insulation glass (VIG) is due to the low gas pressure between the panes of glass. The edge seal must be made accordingly gas-tight. To this end, the two panes of glass are usually joined by metal or glass seals so that a thermal bridge occurs. The influence of the edge seal is represented in the illustration below. The surface temperatures are reduced despite the fact that the edge seal is covered with a highly-insulating frame.

Simulation of the heat transfer through vacuum insulation glass (VIG). Easily recognizable are the thermal bridge effect of the supports between the panes (yellow dots) as well as the strong influence of the edge seal (blue area). The edge seal here has already been covered by a highly-insulating frame.
The influence of the edge seal is dependent on the size of the glass panes. Large dimensions are thermally more favourable since the edge seal makes up less of the total surface. VIG must nevertheless be integrated into a highly-insulating frame construction. Such highly-insulating frame constructions are currently being developed within the framework of a project funded by the German Federal Ministry of Economics and Technology.

Calculated U-values of two glazing systems (VIG and triple glazing) including the influence of the edge seal for different glass sizes. The blue circles show the potential for optimization by using a highly-insulating frame construction. The dotted line shows the Ug-value of VIG without the influence of the edge seal.

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