Selected issues of choosing composite materials for window supporting beams

Abstract In the paper, some issues of choosing composite materials for window mounting elements in thermal insulation is presented. To eliminate places where significant heat losses occur, it is necessary not only to properly design exterior walls, but also to use suitable materials and effective technology of window installation. There are several window installation systems, in each of which there are elements responsible for thermal insulation and supporting elements responsible for system stability and load transfer. Since insulating elements directly affect the temperature distribution in the wall and the eventual occurrence of thermal bridges, they must be made from materials with a low heat transfer coefficient and good humidity parameters, while the supporting elements must be made from high strength materials. In the paper a warm installation system (WIS), in which both elements are replaced with one supporting beam, is analyzed. The beams are made from polyurethane and fiberglass. Some of them are reinforced with steel and aluminum profiles. The effect of the used materials on the heat flow through the external wall and strength of the supporting beams is analyzed both experimentally and numerically (ADINA System). The process of heat exchange between the interior with +20 °C and variable values of outside temperature versus time is simulated. The temperature distribution in the wall as well as the course of the 0 °C isotherm are analyzed. The numerical model for the supporting beam without reinforcement is verified in experiments. In addition to the heat, humidity and mechanical parameters are considered so that the applied solutions are profitable.