Reliable methods are needed for classifying the robustness of buildings and building materials for many reasons, including ensuring that constructions can withstand the climate conditions resulting from global warming, which might be more severe than was assumed in an existing building’s design. Evaluating the robustness of buildings is also important for reducing process-induced building defects. We describe and demonstrate a flexible framework for classifying the robustness of building materials, building assemblies, and whole buildings that incorporates climate and service life considerations.

Published in Journal papers

Vinduer ble lenge betraktet som energisluk i vinter-Norge. Men utstyrt med siste nytt fra forskningsfronten på feltet, kan kontorbygg forbruke mindre energi enn bygninger helt uten vinduer.

One of the most effective actions for reduction of energy loss through the building envelope is to optimize the thermal performance, area and localization of the transparent components in the façade in order to obtain minimal heat losses and optimal solar gains.

When considering the thermal performance of these transparent components, one should consider, not only heat loss (or gains) caused by thermal transmission, but also the beneficial effects of incident solar radiation and hence reduced demand for heating and artificial lighting.

This study presents calculations for a range of windows as part of a building where the coupled effects of incident solar radiation and thermal transmission heat losses are accounted for in terms of a net energy balance for the various solutions. Effects of varying thermal transmittance values (U-values) are studied in connection with solar heat gain coefficients.

Three different rating methods have been proposed and applied to assess the energy performance of several window configurations. It has been found that various rating methods give different energy saving potentials in terms of absolute figures. Furthermore, it has been found that windows, even with existing technology, might outperform an opaque wall in terms of heating and cooling demands.

Published in Journal papers

The main purpose of this book, Hygrothermal, Building Pathology and Durability, is to provide a collection of recent research works to contribute to the systematization and dissemination of knowledge related to construction pathology, hygrothermal behaviour of buildings, durability and diagnostic techniques and, simultaneously, to show the most recent advances in this domain. It includes a set of new developments in the field of building physics and hygrothermal behaviour, durability approach for historical and old buildings and building pathology vs. durability. The book is divided in several chapters that are a resume of the current state of knowledge for benefit of professional colleagues, scientists, students, practitioners, lecturers and other interested parties to network.

Published in Books

The introduction of dynamic envelope components and systems can have a significant reduction effect on heating and cooling demands. In addition, it can contribute to reduce the energy demand for artificial lighting by better utilization of the daylight. One of these promising technologies is Phase Change Materials (PCM). Here, the latent heat storage potential of the transition between solid and liquid state of a material is exploited to increase the thermal mass of the component. 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. Measurements have been performed on a state-of-the-art window that integrates PCM using a large scale climate simulator. The glazing unit consists of a four-pane glazing with an integrated layer that dynamically controls the solar transmittance (prismatic glass) in the outer glazing cavity. The innermost cavity is filled with a PCM, contained into transparent plastic containers. The introduction of dynamic components in the building envelope makes the characterization of static performance (e.g. the thermal transmittance, U-value; the solar heat gain coefficient) insufficient in giving the full picture regarding the performance of the component in question. This article presents a series of measurements, and the related methodologies, carried out on a window with incorporated PCM. The tests have been carried out using several test cycles comprised of temperature and solar radiation cycling, where the aim has been to delve deeper into the possibilities for characterization of dynamic building envelope components by full scale testing in a climate simulator.

Published in Conference papers

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 5–10 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 load-bearing 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.

Published in Journal papers

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