Analytical Model for Computing Thermal Bridge Effects in High Performance Building Panels

Vacuum insulation panels (VIPs) have recently been discovered by the building sector. Because they are evacuated, their ideal or centre-of-panel thermal conductivity is as low as about 0.004 W·m-1·K-1. As a consequence, vacuum insulation panels combine high thermal performance with limited construction thickness. Integrated into building panels, however, a thermal bridge effect occurs at the panel’s edge due to the combined effect of the high barrier laminate around the VIP and the (structural) edge profile along the circumference of the component. Until now, numerical calculation tools are used for estimating the overall thermal performance of building panels. This procedure however is time-consuming and does not give insight into the relations between relevant parameters. This paper therefore presents and numerically validates an analytical model for calculating this thermal edge effect, especially for thermally highly performing building components with vacuum insulation panels as core. The model however is generally valid for thermal shunting effects due to the edge of building panels. Based on a comparison of analytical to numerical data, it is shown that the inaccuracy of the analytical model compared to numerical data is less than about 10 % within limitations specified. 1