Page 17 - ZEB Final Report 2009-2017

Aerogel Possibilities | 17

Malin Sletnes
Researcher, SINTEF

In order to curtail building envelope thicknesses in zero
emission buildings, construction materials with low thermal
conductivity are required. In addition to traditional insulation
of walls, foundations, and ceilings, superinsulation materials
may be integrated in functional units, such as door and window
frames, and in load-bearing components.
Aerogels are among the best thermal insulation materials
available on the market today, with thermal conductivity values
as low as 0.012 – 0.018 W/(mK). Aerogel insulation blankets
are therefore ideal in applications where superior thermal
insulation is required and where there is limited space. Their
share of the market is expected to increase as production costs
are lowered.
To stay ahead of development, Glava, SINTEF, NTNU
and other ZEB partners have investigated the possibilities of FIGURE 1. Thermal conductivity decreases with increasing uniaxial
integrating aerogel in building components by analysing the compression. Thermal conductivity vs. strain is shown for four
thermal conductivity of aerogel insulation blankets under samples each, of two different brands (marked red and blue) of
compression and in humid atmospheres. aerogel insulation blankets.
Our results show that the thermal insulation properties of
aerogel insulation blankets remain excellent under compressive However, the effect of moisture on thermal conductivity may
stresses of up to 40 kaPa, making aerogel integration be a cause for concern. A 32 % increase in thermal conductivity
particularly interesting for building components that are used was observed upon exposure to an atmosphere of 95 % relative
under compression. The thermal conductivity decreased with humidity. Thus, in order to widen the range of applications
increasing uniaxial compression. Hence, it is possible to achieve for aerogel insulation blankets, further investigations should
lower thermal transmittance (U) values by packing more be conducted to understand and improve their hygrothermal
aerogel insulation material into a restricted space. properties.

Instrument setup for studying the effect of relative humidity on Aerogel insulation is available in many forms. Monolithic aerogel
the thermal conductivity of aerogel insulation blankets. is transparent, and is therefore promising for use in highly
insulating glazing systems.

Further reading: Schlanbusch R. Nanotechnology for Improved Thermal Insulation in Buildings [Web page]. Norway: smallPrint; 2013 [updated
16.05.1313.02.17]. Available from: http://smallprint.no/en/article/nanotechnology-improved-thermal-insulation-buildings.
Baetens R, Jelle BP, Gustavsen A. Aerogel Insulation for Building Applications: A State-of-the-Art Review. Energy and Buildings. 2011;43(4):761-9.
Gao T, Jelle BP, Gustavsen A, Jacobsen S. Aerogel-Incorporated Concrete: An Experimental Study. Construction and Building Materials.
2014;52:130-6.