Abstract

A crucial property for double-glazed sealed insulating window panes is to maintain their thermal insulating properties and thus low U-values. However, degradation and thus subsequent reduction or loss of low-conductance gas concentration may occur in the sealed glazing units by their exposure to outdoor climate.

The choice of spacers is important to keep as low thermal transport through the window panes as possible, i.e. low U-value. In addition, the type of spacers may also influence their durability and resistance towards ageing, which hence may be characterized by the low-conductance noble gas concentration, e.g. argon, krypton or xenon. Ageing and degradation of window panes may lead to a decreased or total loss of noble gas concentration and hence subsequent increased heating energy demand in buildings.

Thus, several double-glazed sealed insulating window panes, with aluminium spacers and Super Spacers, have been subjected to accelerated ageing by climate ageing and elevated temperature ageing. The durability and ageing of the sealed window panes have been studied and characterized by their spacer type and gas concentration. Furthermore, the decrease of gas concentration in sealed insulating window panes and the impact on the energy performance and in particular heating demand of buildings have been investigated.

Abstract

Use of photovoltaics (PV) is key remedies in buildings where a large part of the energy supply should be based on renewable energy. PV in Nordic climate can be challenging because of snow, wind and temperatures below zero. The aim of this research work has been to provide a state-of-the art overview of recent experiences and challenges for building physical conditions related to the use of roof-integrated PV in Nordic climate. The study has identified practical guidelines for installation and ventilation of the roofing as challenges to be solved for extensive use of such systems in Nordic climate.

Denne rapporten begrenser seg til å presentere en metode for beregning av kuldebroverdier for tilslutningen mellom yttervegg og golv på grunn (ringmursløsninger). I både NS 3031 og NS‐EN ISO 10211 åpnes det for en forenklet beregning av kuldebroverdien etter en annen internasjonal standard; NS‐EN ISO 13370. Denne beskriver en forenklet prosedyre for beregning av U‐verdien til golv mot grunn basert på en korreksjon til U‐verdier beregnet etter NS‐EN ISO 6946.

Sandwich elements are widely used in the building envelope, in walls and foundations in particular. The thickness of sandwich elements is increasing as the demand for reduced heat loss from the building envelope is required. The building industry is searching for means and alternative materials to reduce the volume of the building envelope, but at the same time obtain the same thermal performance. Sandwich element constructions might be suitable for highly effective insulation materials as VIPs (Vacuum Insulation Panels). The possibilities of optimizing the thermal performance and by the same time decreasing the thickness and reducing the volume of aggregated clay sandwich construction block systems with VIPs has been investigated. Numerical simulations with heat conduction models and also CFD-models have been performed in order to study the optimal design of the block, the influence of thermal bridges and the influence of vertical and horizontal joints on the thermal performance of a wall. The work has resulted in an optimal design for a prototype block which has been produced and general knowledge about the influence of convection in vertical joints. The simulations show that for vertical joints less than 3 mm in width there will be no significant heat transport by convection. The numerical simulations also show that an U-value of 0,08 W/m2K can be achieved for such a system, with a thickness of the block being 300 mm. The work was carried out in the framework of the Norwegian centre for Zero Emission Buildings (ZEB).