The GHP 900 S is able to measure the thermal conductivity of insulation glass … When the HGM mass content increases to 20%, the effective thermal conductivity value of the foam decreases to 0.3087 W/(mK), which corresponds to a 41.9% decrease compared to the pure cement. The thermal conductivity of a material is a measure of its ability to conduct heat. Unless otherwise noted, the values refer to a pressure of 100 kPa (1 bar) or to the saturation vapor pressure if that is less than 100 kPa. On the other hand, the radiation conductivity (thermal conductivity due to photon transport) increases greatly with temperature. The clear decrease in thermal conductivity between 450 °C and 500 °C and 540 °C and 560 °C, respectively, can be related to the above-mentioned glass … Heat Transfer Engineering and Design. The thermal conductivity of acrylic is lower than that of laminated glass. The U-value of an insulation glass window depends on the mounting angle (vertical, horizontal or in between) due to different heat transfer conditions within the gas phase. This has been confirmed by the experiments of Chang and Jones on commercial glasses and glass ceramics, where the mean free paths were found to be limited by "internal boundary scattering" to length scales of … The higher the lambda value, the more heat the material conducts, and therefore, the less it insulates. Gases possess poor thermal conduction properties compared to liquids and solids, and thus makes a good insulation material if they can be trapped (e.g. The thermal conductivity of oxide glass due to atomic vibrations (the so-called phonon mechanism) does not increase appreciably with temperature. Thermal Conductivity When comparing the insulating properties of materials, engineers use the thermal conductivity value or lambda, of the materials. This chart gives the thermal conductivity of gases as a function of temperature. Thermal conductivity, frequently represented by , is a property that relates the rate of heat loss per unit area of a material to its rate of change of temperature. The thermal conductivity of the pure cement is measured to be 0.5312 W/(mK), which corresponds to the case of 0% mass content of HGMs. Typical thermal conductivity values for glass wools are between 0.023 and 0.040W/m∙K. The lower the thermal conductivity of the material the greater the material’s ability to resist heat transfer, and hence the greater the insulation’s effectiveness. In other words the thermal insulation of acrylic is better than of laminated glass. Thermal Conductivity of Gases Chart. Typical thermal conductivity values for glass wools are between 0.023 and 0.040W/m∙K. Essentially, it is a value that accounts for any property of the material that could change the way it conducts heat. Material Insulation; Air: 0.03 W/mK: Acrylic: 0.19 W/mK: Water: 0.57 W/mK: Glass, Laminated: 0.79 W/mK: Implications on Pool Underwater Windows: In general, thermal insulation is primarily based on the very low thermal conductivity of gases . The plot above shows the measured thermal diffusivity and determined thermal conductivity in dependence on temperature.