Insulation materials play an important role in district heating pipeline networks. Thermal losses in pipe insulation systems depend on the thermal conductivity of insulation materials. The thermal conductivity of the insulation materials is influenced by the temperature and moisture content. In this paper the effect of moisture content on the thermal conductivity of rock wool produced by different manufacturers was considered. Experimental studies were performed using the standard guarded hot plate (GHP) method. Higher thermal conductivity is always associated with higher moisture content for all investigated samples.

The insulation materials are widely used in petrochemical, power engineering and other industries. The thermal insulation materials play an important role in the energy saving of district heating systems and in the building sector. In this work, the thermal conductivity of rock wool with different levels of moisture content and density of the insulation material was investigated by an experimental method. Experimental studies were carried out on rock wool from three different manufacturers. The effect of the wetting and drying cycle on thermal conductivity and density of the insulating material is analyzed. The thermal conductivity of the insulating material was measured using the guarded hot plate method. It was found that the thermal conductivity of insulating materials significantly affected the moisture content. The increase in thermal conductivity was from 1.33 to 4.42 times, depending on the density and the manufacturer of the rock wool. The wetting and drying cycles increase the thermal conductivity and density of the insulating material up to 2 and 2.5 times, respectively.