Temperature and Moisture Dependence of the Thermal Conductivity of Insulation Materials

The effective thermal conductivity (keff) of insulation materials is measured according to DIN 52616 /1/at a mean sample temperature of 10 °C with a protected heating plate device (see figure 1). For the building sector this is sufficient, but insulation materials for heat stores are in general exposed to higher temperatures, in the case of hot water stores up to 95 °C. The effective thermal conductivity increases with temperature. For dry insulation materials this effect can be described with a linear approach: