Experimental determination of convection effects on the thermal performance of curtain walls with mineral wool insulation

The total amount of heat transport within mineral wool insulation material, with an air content of more than 98 %, generally depends on the heat conduction within the fibers and the air, on the radiation in the air, and on the convection, i.e. air movement inside the material or penetrating the material. Thus the thermal performance of heat-insulated components is being influenced also by the type and the intensity of air movement, i.e. by the free or forced convection on the surface or within the material, and by different characteristics of the insulation material, such as density, thickness and permeability to air. In laboratory measurements of heat conductivity, e.g. with a guarded hot plate, convection effects are not allowed for in a realistic manner, whereas under in-situ conditions they may degrade the insulation quality.