No abstract

No abstract

Vacuum insulation panels (VIPs) are regarded as one of the most promising existing high performance thermal insulation solutions on the market today as their thermal performance typically range 5 to 10 times better than traditional insulation materials. However, the VIPs have several disadvantages such as risk of puncturing by penetration of nails and that they cannot be cut or fitted at the construction site. Furthermore, thermal bridging due to the panel envelope and loadbearing 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 well with numerical calculated U-values when actual values of the various parameters are used as input values in the numerical simulations.

Many of the Norwegian buildings from the 1960s-1980s with timber frame walls are ready for retrofitting. Retrofitting of these buildings with vacuum insulation panels (VIPs) may be performed without significant changes to the buildings, e.g., extension of the roof protruding and fitting of windows. Effectively, U-values low enough to fulfill passive house or zero energy requirements may be achieved; thus, contributing to a reduction of the energy use and CO 2 emissions within the building sector. Retrofitting with VIPs on the exterior side is normally considered as a better solution; however, it may cause condensation in the wall. To investigate this and the interior option, four different wall fields were tested. One of them was a reference wall field built according to Norwegian building regulations from the 1970s, and three other fields represent different ways of increasing the thermal insulation level. In addition to the experiments, numerical simulations were performed where temperature, relative humidity, and surface wetness were measured. In total, the results from the experiments, simulations, and condensation controls conclude that timber frame buildings insulated with 100 mm Downloaded from mineral wool, might be retrofitted at the outside by adding 30 mm VIPs. However, this method for retrofitting provides limits to outdoor temperature, indoor moisture excess, and indoor temperature.

The goal of this research project was to get more information about the influence of wind pressure on the heat transmission through timber frame constructions and to establish a recommended limit for air permeance of wind barriers.*The project was divided into three parts: wind pressure measurements on a rotatable test house, hot-box measurements on a wall, and calculations. The theoretical studies as well as the experimental investigations in the hot-box, have been restricted to one specific type of forced convection in the thermal insulation, the interchange of air between the insulation and the air gap between the wind barrier and the outer cladding. The results of the project show the importance of protecting the insulation layer with a wind barrier to achieve full effect of the insulation in wind exposed constructions. The measurements indicate that heat loss caused by this type of forced convection can be three to ten times higher than calculated for ideal constructions. Based on the measurements carried out in this project, Norwegian Building Research Institute, NBI, is recommending an upper limit for the air permeance of wind barriers, including joints, of 0.05 m 3 /m 2 h Pa (1.4E-5 m 3 /m 2 s Pa).