While window frames typically represent 20%"30% of the overall window area, their impact on the total window heat transfer  rates may be much larger. This effect is even greater in low-conductance (highly insulating) windows that incorporate very low  conductance glazings. Developing low-conductance window frames requires accurate simulation tools for product research and  development.  The Passivhaus Institute in Germany states that windows (glazing and frames, combined) should have U-factors not exceeding  0.80 W/(m² K). This has created a niche market for highly insulating frames, with frame U-factors typically around 0.7-1.0 W/  (m² K). The U-factors reported are often based on numerical…

Nanotechnology and possibilities for the thermal building insulation materials of tomorrow are explored within this work. That is, we are looking beyond both the traditional and the state-of-the-art thermal building insulation materials and solutions, e.g. beyond vacuum insulation panels (VIP). Thus advanced insulation material (AIM) concepts like vacuum insulation materials (VIM), gas insulation materials (GIM), nano insulation materials (NIM) and dynamic insulation materials (DIM) are introduced and defined. The VIMs and GIMs have closed pore structures, whereas the NIMs may have either open or closed pore structures. The objective of the DIMs are to dynamically control the thermal insulation material…

Electrochromic (EC) materials that change their optical transmittance under an external electrical field may form the basis of “smart windows”, which are of great interest in forthcoming building technologies. Nanostructured EC materials or assemblies have revealed remarkable improvement on colouration efficiency and switching time due to their small featured sizes and large surface areas. Here, the recent progress of nanoelectrochromics is reviewed; the scientific and technical issues related to material preparation and device assembly for large-area and large-scale window applications are discussed.

Phase change materials (PCMs) have opened a new door towards the renewable energy future due to their effective thermal energy storage capabilities. Several products have recently found their way to the market, using various types of PCMs. This paper focuses on one particular wall-board product, integrated in a well-insulated wall constructed of an interior gypsum board, PCM layer, vapor barrier, mineral wool, and a wind barrier. The wall is tested with and without the PCM layer in order to get comparative results. Experiments are conducted in a traditional guarded hot box. The hot box is composed of two full-scale test…

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…

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…

Smart windows like electrochromic windows (ECWs) are windows which are able to regulate the solar radiation throughput by application of an external voltage. The ECWs may decrease heating, cooling and electricity loads in buildings by admitting the optimum level of solar energy and daylight into the buildings at any given time, e.g. cold winter climate versus warm summer climate demands. In order to achieve as dynamic and flexible solar radiation control as possible, the ECWs may be characterized by a number of solar radiation glazing factors, i.e. ultraviolet solar transmittance, visible solar transmittance, solar transmittance, solar material protection factor, solar…