Abstract The building envelope plays a crucial role in reducing operational energy demand. In particular, the two main properties of the building envelope to look at in this perspective are thermal transmittance (U, W/m2K1) and thermal inertia, which is often expressed by a metric called periodic thermal transmittance (Yie, W/m2K1). These two properties are also traditionally connected to two different energy demands: while thermal transmittance is crucial to reduce heating energy demand, thermal inertia has an impact on energy demand for cooling. However, a question may rise about the impact of each property on the other demand – i.e. the…

Abstract The building envelope plays a crucial role in reducing operational energy demand. In particular, the two main properties of the building envelope to look at in this perspective are thermal transmittance (U, W/m2K1) and thermal inertia, which is often expressed by a metric called periodic thermal transmittance (Yie, W/m2K1). These two properties are also traditionally connected to two different energy demands: while thermal transmittance is crucial to reduce heating energy demand, thermal inertia has an impact on energy demand for cooling. However, a question may rise about the impact of each property on the other demand – i.e. the…

Summary At the Research Centre on Zero Emission Buildings of NTNU, a new test facility (Living Laboratory) is currently in the final stage of construction and will start its operation in summer 2015. The Living Laboratory was designed to carry out experimental investigations at different levels, ranging from envelope to building equipment components, from ventilation strategies to action research on lifestyles and technologies, where interactions between users and low (zero) energy buildings are studied.The test facility is a single family house with a gross volume of approximately 500 m3 and a heated surface (floor area) of approximately 100 m2. It…

Abstract Introduction of more dynamic building envelope components have been done throughout the last decades in order to try to increase indoor thermal comfort and reduce energy need in buildings for both temperature and light control. One of these promising technologies is phase change materials (PCM), where, the latent heat storage potential of the transition between solid and liquid state of a material is utilized as thermal mass. A PCM layer incorporated in a transparent component can increase the possibilities to harvest energy from solar radiation by reducing the heating/cooling demand and still allowing the utilization of daylight. The introduction…

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.

Abstract There is an increasing interest in development of coupled multi-layer window structures. This is to optimize thermal properties and to develop systems with a better climate protected solar shading system. The risk of condensation on the inside of the exterior glass layer in a multi-layer window structure might be a challenge and is often questioned. The risk of condensation will depend on both window properties and indoor and outdoor climate conditions. The air gap between the inner and outer part have to be ventilated with outdoor air to give the window a "drying out" capacity. The U-value of the…