A large amount of the buildings in Norway is from the 1970s. Many of these buildings have timber frame walls and are now ready to be retrofitted. Application of vacuum insulation panels (VIPs) can make it easier to improve the thermal insulation in building walls with a minimal additional thickness. Retrofitting of buildings using VIPs may therefore be done without large changes to the building, e.g. extension of the roof protruding and fitting of windows. Additionally, U-values low enough to fulfil passive house standars or zero energy building requirements may be achieved. Thus, contribute to a reduction of the energy use and CO2 emissions within the building sector. This work investigates two different ways of retrofitting timber frame walls, one with VIPs on the cold side and one with VIPs on the warm side. A wall module containing four different fields is built and tested between two climate rooms with indoor and outdoor climate, respectively. The module consists of one reference field representing a timber frame wall built according to regulations in the 1970s in Norway, and three fields representing different ways of improving the thermal insulation of the reference field with VIPs. As VIP is a vapour tight barrier, the fields are tested with respect to condensation risk. A new sensor for measuring surface condensation called the wetness sensor is introduced. The results of the experiment show that this method of retrofitting may be acceptable in certain structures within limited climate zones, humidity classes, and building envelopes.

Published in Conference papers

Vacuum insulation panels (VIP) is a high performance thermal insulation material solution with thermal conductivity values reaching as low as 4.0 mW/(mK). With time the thermal performance of the VIPs will degrade as moisture and gas permeate through the barrier envelope of the panels. To better evaluate these ageing effects, accelerated ageing experiments are needed. VIPs consist of a porous core of pyrogenic silica (SiO2) and a gas and vapour tight envelope. The external factors that are found to contribute most to ageing of VIPs are temperature, moisture and pressure. Several experiments have been initiated to evaluate the acceleration effects by the application of severe temperature, moisture and pressure conditions, including: 1. Thermal ageing at 80°C for 180 days according to CUAP 12.01/30 2. Exposure to cyclic climate in a vertical climate simulator according to NT Build 495. One VIP sample is fully exposed in the simulator and one is placed in a wooden frame structure. 3. Exposure to high vapour pressure by storage at 70°C and 90-100 % RH for 90 days. The increases in thermal conductivity during ageing were relatively small compared to the initial thermal conductivity of the VIPs, which is in agreement with the theoretical predictions. The temperature and moisture experiment seemed to achieve a rather large acceleration effect. In addition, the thermally aged VIP and the exposed VIP in the climate simulator show physical alterations. E.g. swelling, curving and delamination of the outer fire protection layer are observed.

Published in Conference papers
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