Sammendrag
Buildings account for a significant part of the energy use and greenhouse gas emissions. Therefore one has to improve the energy efficiency of buildings. Concepts like passive houses and zero emission buildings are being introduced. Applying traditional techniques and materials in these buildings will significantly increase the amount of traditional thermal insulation, e.g. wall thicknesses up to about 400 mm are expected in passive houses. Such large thicknesses are not desirable due to several reasons, e.g. floor area considerations, efficient material use and need for new construction techniques. Hence, new highly thermal insulating materials and solutions are being sought. In this respect, vacuum insulation panels (VIPs) are regarded as one of the most promising existing high performance thermal insulation solutions on the market today. Thermal performance typically range 5 to 10 times better than traditional insulation materials (e.g. mineral wool), leading to substantial slimmer constructions. However, the VIPs have several disadvantages which have to be addressed. The robustness of VIPs in wall constructions is questioned, e.g. puncturing by penetration of nails. Moreover, the VIPs can not be cut or fitted at the construction site. Furthermore, thermal bridging due to the panel envelope and load-bearing elements may have a large effect on the overall thermal performance. Finally, degradation of thermal performance due to moisture and air diffusion through the panel envelope is also a crucial issue for VIPs. In this work, laboratory investigations have been carried out by hot box measurements. These experimental results have been compared with numerical simulations of several wall structure arrangements of vacuum insulation panels. Various VIP edge and overlap effects have been studied. Measured U-values from hot box VIP large scale experiments correspond quite well with numerical calculated U-values when realistic and measured values of the various parameters