Translucent aerogel insulation

Figure 8 Passive solar heating with a translucent aerogel insulation in front of a blackened house wall. Even on cold but sunny days heat gain can be achieved.

Figure 45.2 Translucent aerogel Insulation used in a curtain waii at the Scuipture building and gallery of Yale University (New Haven, Connecticut, USA) [32].

Figure 45.6 Two examples of translucent aerogel insulation as a high-performance thermal insulation solution for daylighting [85],...

Due to the absence of a stabilising pressurisation in mechanically tensioned structures, another type of aerogel insulation is employed. This version is a fleece made of two-component fibres which is sprinkled with aerogel particles. This produces a flexible and pressure-resistant mat which has highly favourable insulating properties. This fleece can be used both in combination with transparent ETFE foils and with translucent membrane materials such as PTFE-coated, glass-fibre fabric - see Fig. 12.4. The... 

The company has developed several series of products, such as super-thermal insulation flexible felts, thermal insulation panels, thermal insulation cylinders and special-shaped parts, translucent thermal insulation panels, siUca aerogel powders and particles. These products can be widely applied in aerospace and aeronautics, metallurgy, chemical plant installations, oil pipes, refrigerators, cars, ships, buildings, etc. 

SILICA AEROGEL AS A TRANSLUCENT THERMAL INSULATING MATERIAL... 

Aerogels are particularly well suited for insulation applications because of their exceptionally low density, thermal stability, and high transparency. In fact, they can have a thermal conductivity only one-third that of polyurethane or polystyrene foam, and with recent process improvements that reduce the cost of manufacmre by an order of magnitude their practical use in certain construction applications is now feasible [31]. The insulating properties can be enhanced through the addition of IR opacifiers [32]. The high transparency of aerogels makes them suitable as insulation in windows or translucent panels. 

One of the most promising options of flexible insulation materials to be used for translucent foil structures involves granular silica aerogel as insulation material - see Fig. 12.2 (Cremers, 2008). Not only does aerogel have excellent thermal-insulation properties (see r-values and /-values in Fig. 12.3), but it is translucent as well. 

Translucent sandwich panels for the side-facades were also made of glass-fiber-reinforced polyester composites (see Figure 1.8). The sandwich panels consisted of two layers separated by a composite fiber sheet with trapezoidal corrugations. The surface of the facade panels was finished with fleeces that also provide resistance to aging and U V radiation. As the main function of these facade elements was thermal insulation, the sandwich panels were filled with aerogels. They were therefore able to provide a K-value of 0.4 W m with a panel thickness of only 50 mm [18]. In terms of building fire considerations, a sprinkler system was installed as an active fire protection. 

In case of the thermal insulation, the technical limits are nearly reached today and a further improvement will affect aspects like the units transparency (yiP - Vacuum Insula-ti(Mi Panels) or their maximum size, not mentioning the costs. A functional transparent vacuum insulating unit with U-values of 0.1 W/(m K) is not available by now due to the technical problems of keeping the system permanently gas-tight. Therefore, the use of translucent Silica Aerogels, as a highly efficient insulating material inside the/Gf/ s cavity, represents the best possible thermal insulation at the moment. 

On the other hand, silica aerogel has also optical function, translucent or transparent, as described in another section (Chapter 3). This excellent thermal insulating material is most ideal for solar energy application. 

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