Thermal Conductivity Coefficient Research On Mineral Wool After Partial Immersion in Water and Drying to Constant Mass

Abstract

This work concerns the thermal conductivity coefficient of mineral wool. Thermal conductivity coefficient is the basic parameter characterizing thermal insulation materials. Its value depends on various parameters. One of such parameters is the moisture content of the material. The value of the thermal conductivity coefficient rises as the water content of the material increases. The thermal conductivity coefficient of damp mineral wool can be found in various publications. The purpose of this work was to check whether the thermal conductivity coefficient of mineral wool changes after subjecting the material into water at specific time intervals and after drying to a constant mass. The scope of the study included measuring the thermal conductivity coefficient of mineral wool in three processes: before immersion in water, at the time of removal from water and after drying again. The measurements were made at an average temperature of 10°C and a temperature difference of 20 K sample thickness. Fourteen test specimens with a density in the range (74÷127) kg/m3 were tested. Due to the type of mineral wool, the samples were divided into four groups. Test specimens 30, 40 and 50 mm thick were immersed in water to a depth of 10 mm for 1, 7, 14 and 28 days. After this time, the samples were dried to a constant mass and the thermal conductivity coefficient was measured. According to the obtained research results and statistical tests, it was found that the influence of water and redrying on the thermal conductivity coefficient of the mineral wool is insignificant. The largest difference between the initial value of thermal conductivity coefficient and the coefficient value after immersion in water and drying of the same sample was 0.9% and was less than the uncertainty of measurement (3%).