Microtherm® SlimVac – the long life VIP for the most demanding applications.
Thermal security for up to a century?
With a microporous core and an outer covering of "state of the art" barrier film, a Microtherm® SlimVac panel will give dependable protection and peace of mind for decades.
The background that allows us to make this claim with confidence is as follows ...
EMPA, the internationally renowned Swiss research centre, have established a rate of pressure increase in the best vacuum insulation panels of around 1 mbar/year. This is based on the ultra-low permeation rates of modern multi-layer polymer materials. It is now an accepted figure in the industry.
Our own material scientists have measured the effects of pressure increase in the microporous insulation core of a Microtherm® SlimVac panel.
What is immediately apparent is the very slow rate of increase in thermal conductivity as the core pressure of the SlimVac® panel increases. This is a characteristic of the microporous insulation and occurs without the influence of a chemical getter.
Dependable performance from our VIPs for many years.
The Forschungsinstitut für Wärmeschutz e.V. in Munich, more commonly known simply as FIW München, has established an enviable reputation as a leading consulting services provider specialising in the thermal performance of buildings. More details at www.fiw-muenchen.de
FIW München measured the centre panel thermal conductivity of a recently manufactured Microtherm® SlimVac panel at 4.2 mW/m.K at 20 °C mean. After accelerated aging over 6 months as described in their official report no. L1-09-057, the thermal conductivity had risen slightly to 4.8 mW/m.K. Their estimation, in the report, of the predicted TC after 15 years at room temperature is just 5.3 mW/m.K.
So what does all of this really mean?
ASTM C1484-09, the "Standard Specification for Vacuum Insulation Panels", quotes Thermal Resistivity of VIPs as typically from 87 to 870 m.K/W at 24 °C mean. That effectively means that a VIP can have a thermal conductivity as high as 11.5 mW/m.K and still be classified as a panel of superinsulation.
Referring now to our chart of TC against pressure, a TC of 11.5 mW/m.K would be expected at a core pressure of around 150 mbar. In fact, at a pressure of 100 mbar, the expected TC would be around 9 mW/m.K – still an effectively performing vacuum insulation panel and still many times better than any conventional insulation.
Going back to our opening statement relating to the EMPA findings, at a rate of pressure increase (rate of deterioration of the core vacuum) of 1 mbar/year, to reach a core pressure of 100 mbar could take up to 100 years. At this point the panel would still be expected to perform satisfactorily assuming no accidental surface damage to the barrier material from any external influences.
So there you have it – Microtherm® SlimVac, the "century VIP"!