Thermal bridges of metal fasteners for aerogel-enhanced blankets

The use of silica aerogel-enhanced blankets as a thermal insulation material is one of the most promising solutions to reduce the heat loss through the building envelope. Aerogel-enhanced blankets provide exceptionally high thermal resistance, thanks to a thermal conductivity value as low as 0.014W/mK. However, a challenge in the use of aerogel-enhanced blankets is represented by the way to connect these highly flexible panels to the backing support. This paper describes the effect of mechanical fasteners over the thermal performance of a brick wall covered with an aerogel-enhanced blanket investigated. The effective thermal transmittance of the selected aerogel-enhanced blanket due to the presence of the metal fasteners is evaluated experimentally using a calibrated chamber. The laboratory measurements are also compared with theoretical calculations conducted both for metal and plastic fasteners. Finally, some conclusions about the ways to reduce the thermal bridging effects during the installation of aerogel-enhanced blankets are provided, and the effective thermal conductivity of aerogel blankets considering different materials (plastic or metal anchors) for their fastening are reported. (C) 2019 Elsevier B.V. All rights reserved.