What are VIPs?
VIPs – or vacuum insulation panels – are flat panels for optimised temperature insulation that are based on the principle of the thermos flask. These panels offer unparalleled heat insulation at minimum thickness.
What are VIPs made of?
The pressure-resistant core material consists of a compressed plate of micro-porous powder. The core is evacuated (pumped void of air) and sealed in a high-barrier film using a special technique. The special foil used in the manufacturing of VIPs also offers protection against air and water intrusion.
What can VIPs do?
VIPs offer ten times higher thermal insulation than traditional insulation materials of the same thickness. For example: 2 cm of VIP insulation will replace 20 cm of fibre or foam insulation. VIPs also offer a service life of up to 50 years. Refrigerators equipped with our VIPs use up to 50% less electricity. Containers with VIPs provide up to five days constant temperature for heat or cold-sensitive cargo – without any external power supply. Using VIPs in new building construction or in renovation will significantly reduce heating costs and therefore improve the carbon footprint.
Where are VIPs used?
VIPs are used wherever precise heat insulation is required, but the available space is limited.
va-Q-tec 's innovative and eco-friendly VIPs are used in thermal packaging for the pharmaceutical sector, in refrigerators, buildings, technology and industry and in the automotive and aviation sectors.
Durability of VIPs
The lifespan of vacuum insulation panels depends on the characteristics of the film, the size of the pores of the core materials and on the thickness of the panel.
The film of the VIPs drastically reduces the transmission of water vapour and air. A dry ambient condition for the VIP is very important, because high humidity can influence the VIPs film. Accordingly, the lifespan of a 10mm VIP is reduced to half compared with a 20 mm VIP. For 40 mm VIPs the lifespan doubles.
Increase of Gas Pressure
Long term investigations with 20 mm thick micro-porous Silica VIPs, which were wrapped into a metallized high barrier film, show that the gas pressure at ambient temperatures does not rise more than one mbar per year.(see Fig. 3)
That means the increase of gas pressure after 50 years is about 50 mbar. This corresponds to a rise of thermal conductivity to a maximum of 0.008 W/mK. Thus the lifespan of a 20 mm thick VIP can last 30 to 50 years. A good barrier against penetrating gases is an aluminium laminated film. This however causes heat leakage at the VIP edge and is thus only suitable for large vacuum insulation panels.
Metallized film, i.e. a very thin aluminium layer within a high barrier film avoids these heat bridges. Micro-porous Silica has the smallest pore size: smaller than 0.5 µm. Thus the thermal conduction of air is mostly suppressed even at higher gas pressures. Even at a gas pressure of 50 mbar the thermal conductivity of a Silica VIP is only 0.007 W/mK, not even double the value it would be at complete evacuation.
Quality Control of Film
For quality control and development of advanced products it is not only necessary to know the actual gas pressure within the VIP but it is also important to measure the change of gas pressure.
Previous measurements took a long time to achieve reliable results. Therefore va-Q-tec developed several methods which allow us to obtain information on the increase of gas pressure within a short time period and thus to perform accelerated ageing tests.
The illustration above shows the rise of gas pressure within a specially prepared vacuum panel. Measurements are done with help of the va-Q-check® system. As the measurement was started within a low gas pressure area, it is possible to assess the increase rate of the gas pressure fairly accurately within two weeks.
These methods help va-Q-tec control the barrier properties of delivered films, the gas pressure of any produced VIP and to develop new and improved kinds of vacuum insulation products.