Standard-based analysis of measurement uncertainty for the determination of thermal conductivity of super insulating materials

Abstract

The assessment of the thermal performance of super insulating materials (SIM), characterized by thermal conductivities down to 0.002 W/(m K), is strongly influenced by even small absolute measurement uncertainties. Moreover, current standard measurement devices are constructed mostly for the so-called conventional insulation materials with values down to 0.015 W/(m K) and subsequently higher thicknesses of the investigated panels compared to SIM. For these reasons, this paper describes methods to determine the standard-based measurement uncertainty for the determination of thermal conductivity of SIM. A sensitivity study shows that temperature difference and thickness determination are the most influential parameters. Therefore, it is recommendable to use adequate temperature differences above 15 K and to take special care about the method for the determination of the panel thickness that may depend also on the flatness and torsion of the investigated panel.