For the sustainable development in the building sector it is crucial that transmissive heat losses will be eliminated almost entirely. In order to avoid bulky insulating layers, high performance insulation with superior performance i.e. reduced thermal losses are required.
We are developing new high-performance Insulation systems on the basis of ecenonmical and scalable technologies which are setting tomorrows new standards for energy efficiency.Generally we differentiate two forms of high-performance insulation systems:

• evacuated systems: Vacuum insulation panels (VIP) und vacuum insulation glazing (VIG). Such systems allow fort he highest possible insulation performance. Their drawbacks are performance deterioration through aging and increased sensitivity to mechanical damage.
  
  
• non-evacuated systems: As an alternative to evacuated systems, fiber-reinforced Aerogel insulation can be used. This nanoporous system has the is significantly less sensitive to mechanical damage and does not show any aging effects.
  
  

In addition, we are dealing with topical questions in the field of materials and technologies relevant for buildings, characterization, coating and functionalization as well as humidity-related and optical properties. We also offer a range of building materials and components testing services.

Vacuum insulation glazing

Vacuum-Insulation Glazing (VIG) denotes a novel type of high-performance insulation glazing, which shows superior insulation performance despite its significantly reduced total thickness. As suggested by ist name, the space in between two glass panes is evacuated, which largely eliminates thermal conduction through collisions and convection of gas molecules. If low-E coated glass is used, total heat transfer coefficients for a double glazing unit of 0.2 - 0.5 W/(m2*K) can be reached. These values are a factor of 2 -5 lower than todays state-of-the-art glazings (1.0  W/(m2*K)  for double glazing).

Currently, several research groups worldwide are pusuing an econimical and technically suitable process for large scale manufacture of VIG. The main difficulty to overcome is still the development of a mechanically stable and leak-tight edge sealing method. During the last year we have developed a technology for VIG edge sealing which is superior, particularly from an economic point of view, to all other methods known to date. This technology is in the process of being patented and should lay the foundation for a new generation of VIG products.

Vacuum Insulation Panels

If a microporous bulk material is partially evacuated, the dominant heat transfer mechanism through gas molecules can be eliminated to a large extent. Compared to conventional insulation, a vacuum insulation panel VIP has a roughly 5 to 10 times higher thermal resistivity  3…6 mW/(m*K). In contrast to the thermal advantage, VIPs are significantly more expensiv, have limited service life and are extremely sensitive to perforation and mechanical damage.

The largest potential for improvement of such encapsulated VIP systems is in the fields of components (multilayer laminate foils and microporous core materials) optimization and alternative system concept design. With regard to the first, we are investigating and testing new materials combinations in order to provide new innovative solutions. Our goal is to understand heat transfer mechanisms in such nanostructured materials and derive improved materials combinations from this knowledge. We are developing VIP insulation with single and multilayer laminate gas barrier foils in collaborations with industry partners. The use of getter materials is incorporated into our systems design.

SiO2 Aerogel as a high-performance insulation

Aerogels can be assembled from a variety of inorganic or organic building blocks. In addition, the length scale of their building blocks or so-called „beads“ as well as the resulting pores can be tailored over a large range from a few nm to several ym. Because of their egregious physical properties, aerorgel materials have received great attention from the fundamental science and structural characterization community. Since the turn of the Millennium, they also find more and more use in the packaging and thermal insulation industry.
Commercial producers in the U.S. are offering SiO2-based aerogels which were manufactured by a supercritical drying method. Our research efforts in collaboration with the Zurich University of Applied Sciences ZHAW are centered around a non-supercritical drying production process. Currently we are able to produce fiber-reinforced aerogel mats with a thermal resistivity  of 14 mW/(m*K). We are also investigating the correlation between lambda and the bulk nanostructure of these materials by small angle X-ray scattering SAXS. Those experiments are carried out In collaboration at the Swiss Synchrotron Light Source SLS at the Paul Scherer Institute PSI in Villigen. Those results reveal new structure-property information about such silica aerogels and again provide insight into heat transfer mechanisms connected with the nanoscale. 

We offer services which are oriented towards industry-, commerce-, union- and federal office needs. First and foremost we provide testing and characterization in the field of our main R & D activities. Those fall into the following categories (experiment and numerical modeling):

• Characterization of building components and systems from a physical point of view (Thermal and humidity related properties)
  
  
• Determination of thermal and radiative behaviour of glazed window and facade elements.
  
  

Contact:
Dr. Matthias Koebel
Empa, Building Technologies Laboratory
Überlandstrasse 129
CH-8600 Dübendorf
T +41 44 823 55 11
F +41 44 823 40 09

Matthias.Koebel@empa.ch