Future-oriented sustainable building materials/components in Europe - Part A: Insulation Materials

Aerogels

Technical details

• Consist of 99%  air and 1% silica/metal/rubber.
• Formed by dehydrating gels.
• Are extremely light because of the resultant porous structure, e.g. 1m³(silica)=2000kg, 1m³(silica aerogel) = 20kg.

Application

• Best suited for applications such as skylights, where a clear line of sight to the exterior is not required, but only daylight.
• Aerogels are lately finding commercial applications as building insulation as well (typically in form of blanket insulation).

Performance

• Replacing the air gap in double glazing with an aerogel improves the insulation value by a factor of three, against the very best current multiple glazing. It would be possible to achieve a 99% vacuum between the panes, since a solid supports them.
• The thermal properties of aerogels also make them ideal for harvesting solar heat: Flat plate solar panels could collect heat and then radiate it back into space.
• R-Value=0.014 mK/W

Advantages/Disadvantages

• +Have a relatively high mechanical strength and a lightweight structure at the same time.
• +Excellent insulators
• -High cost of production has initially limited their application to high end industrial and space applications.
• -Even with a thin aerogel sandwich the window would have a slightly frosted appearance.

Vacuum insulation panels (VIPs)

Technical details

• Formed by creating a vacuum in the hollow core between two tightly sealed rectangular panels. The walls of the panels are made of rigid, yet highly porous materials such as treated silica, perlite or glass fiber. The entire panel is then enclosed with a barrier film typically made of aluminum metallization.

Application

• They are mostly used for insulating walls and roofs.
• Best suited to be used in prefabricated panels.

Performance

• Very good insulation properties.
• R-Value=0.003-0.005 mK/W

Advantages/Disadvantages

• +Offer superior insulation properties compared to all other building insulation materials.
• -Their cost and handling still act as barriers to their wide spread application.
• -VIPs are not as flexible as other insulation materials which can be cut on site into different sizes.