Assessment of Thermally Induced Stress in BIPV Modules using FEM Simulations

Environmental conditions like irradiation and temperature cause thermally induced stresses in building-integrated PV modules. This study investigates the influences of different design parameters and additionally environmental conditions on the thermally induced stresses within the glass of BIPV modules. A thermomechanical 3D FEM model of a glass-glass BIPV module in an example ventilated façade is used to perform parameter sensitivity studies. Among the investigated variations, partial shading has the strongest impact. All simulated variations result in maximum stresses above the design edge resistance of annealed glass. Therefore, the use of annealed glass is risky, while the design edge resistance of thermally toughened glass was not exceeded in any variation. From the detailed 3D FEM model, a simplified 2D FEM model was derived for the purpose of a quick and easy estimation of the thermally induced stress. The approach "Determination of thermomechanical resistance to partial shading"” was proposed for discussion by the standardization committee responsible for revising EN 50583:2016.