Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Umberto Berardi"

Recent trends in superinsulation materials for building - aerogel-enhanced products DOI:10.15199/33.2019.01.03

  In an effort of setting stringent energy saving targets, the building sector has received increasing attention, as buildings are responsible for consuming up to 40% of the total energy in several developed countries, and contribute 40% to the total greenhouse gas emissions [6]. In this context, insulating material companies and researchers are struggling to create products with the lowest possible thermal conductivity at a reasonable price in order to promote high-performance building envelopeswithin thin layers.While common insulating materials have typical thermal conductivity values around 0.05W/mK, materials with a thermal conductivity well below 0.02W/mK have been consistently presented recently. Super-insulating materials, whose thermal conductivity is well below that of commonly adopted products, have received increasing attention. In particular, aerogels have received an increasing attention over the last decade since they show one of the lowest possible thermal conductivity [1, 2]. Aerogels are synthetic and highly porous nanostructured materials, inspired by a 1931 patent of Steven Kistler. The term "aerogel" comes from the fact that they are produced from gels in which the liquid component of the gel is replaced with a gas, giving to the final product a solid and dry smoked aspect. Compared to any other known material, an aerogel has the highest porosity, the highest specific surface area, and the lowest density, typically 70 ÷ 150 kg/m3. The low thermal conductivity of aerogels is a result of the high porosity and the nano-dimensional size of their pores. On the other hand, aerogels are very brittle due to their low tensile strength and are particularly expensive. Consequently, instead of being used alone, they are typically embedded in other materials (Photo 1). This paper is dedicated to present the current state of the art about aerogel- -enhanced opaque insulations. Aerogel synthesis and mark[...]

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