Among the newest and most efficient solutions for the thermal insulation of buildings is theairgel, a material also known as 'frozen smoke' which is essentially obtained from silica, carbon and alumina through a gelation process in a solvent.
That ofairgel it is actually a technology already consolidated in some sectors, starting with the aerospace one where it has long been used for astronaut suits. The novelty is represented by the applications ofairgel in construction in the insulation of the building envelope.
L'airgel in the form of insulating sheets, it is an energetically very efficient solution for the thermal insulation of all building components (walls, roof, floors ...) because it has a thermal conductivity index between 0.005 and 0.015 W / Mk, were it not even very expensive it would certainly be more widespread in the residential sector.
Today the cost of a panel of airgel it is approximately 10-15 times higher than traditional insulators for every centimeter of insulating layer. However, it has been shown that for the same isolation to be achieved, a quantity of airgel equal to 1/3 - 1/5 compared to traditional insulators.
How is theairgel? To create it for the first time in the laboratory was Steven Kistler in 1931, to make it famous were instead the suits of the NASA astronauts. At the base there is a process of gelling the silica in a solvent, eliminating which what remains is a nanoporous solid similar to 'swollen sand'. The porosity is such as to slow down the transport of heat and give theairgel the very low thermal conductivity index mentioned above.
Today theairgel it is produced and marketed in panels (including vacuum panels) which have dimensional stability, mechanical integrity and shape such as to make it usable on any surface. We have said that the price is quite high, but it is also true that in the technical-economic evaluations relating to the insulation of a building (new or to be redeveloped) the incidence of the cost of the insulation is limited compared to the intervention in its complexity, and the the possibility of achieving high performance with low thicknesses is certainly an advantage.
In the overall energy efficiency of a building, the envelope counts more than the systems. An energy efficient envelope as can be obtained with theairgel considerably reduces consumption and the thermal power of the system, to the benefit of innovative plant solutions and the possibility of exploiting renewable energy sources.
Insulating solutions for buildings based onairgel it remains to evaluate the comfort in terms of breathability and thermohygrometric well-being, prerogative of natural organic insulators such as wood fiber, cork, sheep's wool and cellulose. Another aspect to be explored is that of the environmental impact of the production cycle ofairgel.
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