An Analytical Model for Calculating Thermal Bridge Effects in High Performance Building Enclosure

Although vacuum insulation panels (VIPs) are excellent thermal insulators, edge effects decrease their overall thermal performance. Moreover, they are often used with protections, such as integration into a panel. These panels typically use spacers that cause a significant additional thermal bridge. The effect of this thermal bridge is either determined accurately with numerical simulation tools or estimated with simple thermal resistance networks. The first approach is laborious, while the latter approach lacks accuracy. This study therefore presents and validates an analytical approximation model for calculating this thermal edge effect. A comparison of this model with numerical simulation shows that it can be applied with an inaccuracy of <10%. The total inaccuracy, however, also includes an error due to the schematization of the edge of the building panel. Yet, this model appears to be very useful for estimation of the linear thermal transmittance of the edge of building panels.