Publications
The suitability of air-heating in residential passive house buildings from the occupant’s point of view
Authors:
Publication Year:
2015
Authors:
Publication Year:
2015
Abstract The substantial reduction of required heating load in passive house buildings has led to an integration of heating in the ventilation system by post-heating the supply-air, called air-heating. The incorporation of heating in the ventilation system constitutes a departure from a well-established customary practice of strictly separating heating and ventilation in the indoor climate design. It is therefore imperative to thoroughly investigate and evaluate air-heating with regard to effects on the indoor air quality (IAQ) and thermal comfort. Simulations and laboratory measurements suggest that air-heating has no adverse effects on IAQ and thermal comfort. The purpose of this paper…
Published in
Journal papers
Identifying key design parameters of the integrated energy system for a residential Zero Emission Building in Norway
Authors:
Publication Year:
2015
Authors:
Publication Year:
2015
Abstract This study examined an integrated solution of the building energy supply system consisting of flat plate solar thermal collectors in combination with a ground-source heat pump and an exhaust air heat pump for the heating and cooling, and production of domestic hot water. The supply energy system was proposed to a 202 m2 single-family demo dwelling (SFD), which is defined by the Norwegian Zero Emission Building standard. The main design parameters were analyzed in order to find the most essential parameters, which could significantly influenced the total energy use. This study found that 85% of the total heating demand of the…
Published in
Journal papers
Performance of a lab-scale membrane-based energy exchanger
Authors:
Publication Year:
2015
Authors:
Publication Year:
2015
Abstract Efficient energy recovery from used air with the goal of reducing energy use is important for realizing low energy houses. Rotary heat exchangers are very energy efficient, but have the drawback of transferring odours from exhaust air to fresh supply air. To avoid this, flat plate heat exchangers are commonly used where odour transfer might cause problems. Nevertheless, these may not properly handle water condensation and frost formation at low outdoor temperatures. The so-called membrane-based energy exchangers are an alternative to the flat plate heat exchanger. In a membrane-based exchanger, moisture is transferred from the humid exhaust air to…
Published in
Journal papers
Perspective of aerogel glazings in energy efficient buildings
Authors:
Publication Year:
2015
Authors:
Publication Year:
2015
Abstract The application perspective of aerogel glazings in energy efficient buildings has been discussed by evaluating their energy efficiency, process economics, and environmental impact. For such a purpose, prototype aerogel glazing units have been assembled by incorporating aerogel granules into the air cavity of corresponding double glazing units, which enables an experimental investigation on their physical properties and a subsequent numerical simulation on their energy performance. The results show that, compared to the double glazing counterparts, aerogel glazings can contribute to about 21% reduction in energy consumptions related to heating, cooling, and lighting; payback time calculations indicate that the return…
Published in
Journal papers
User evaluation of the indoor climate of the first passive house school in Norway
Authors:
Publication Year:
2015
Authors:
Publication Year:
2015
Abstract The indoor climate of the first passive house school in Norway was evaluated with the aid of a questionnaire (Örebro) with approximately 340 respondents, and three interview rounds with a total of 23 informants. The intention was to reveal whether the users experienced any problems or possibly better conditions than in a regular school building. The interviews showed that, overall, the users were satisfied with the building. The survey showed generally good results for the indoor climate. Questionnaire results were compared with reference material consisting of data for average school buildings. The indoor climate of Marienlyst School was better…
Published in
Journal papers
Accelerated ageing and durability of double-glazed sealed insulating windows panes and impact on heating demand in buildings
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
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…
Published in
Journal papers
Performance of a lab-scale membrane-based energy exchanger
Authors:
Publication Year:
2015
Authors:
Publication Year:
2015
Abstract Efficient energy recovery from used air with the goal of reducing energy use is important for realizing low energy houses. Rotary heat exchangers are very energy efficient, but have the drawback of transferring odours from exhaust air to fresh supply air. To avoid this, flat plate heat exchangers are commonly used where odour transfer might cause problems. Nevertheless, these may not properly handle water condensation and frost formation at low outdoor temperatures. The so-called membrane-based energy exchangers are an alternative to the flat plate heat exchanger. In a membrane-based exchanger, moisture is transferred from the humid exhaust air to…
Published in
Journal papers
Search for the optimal window-to-wall ratio in office buildings in different European climates and the implications on total energy saving potential
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract This paper deals with the search for the optimal window-to-wall ratio (WWR) in different European climates in relation to an office building characterized by best-available technologies for building envelope components and installations. The optimal WWR value is the one that minimizes, on an annual basis, the sum of the energy use for heating, cooling and lighting. By means of integrated thermal and lighting simulations, the optimal WWR for each of the main orientations was found in four different locations, covering the mid-latitude region (35° to 60° N), from temperate to continental climates. Moreover, the robustness of the results was…
Published in
Journal papers
Embodied greenhouse gas emissions from PV systems in Norwegian residential Zero Emission Pilot Buildings
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract Greenhouse gas (GHG) emissions from the combustion of fossil energy need to be reduced to combat global climate change. For zero energy and Zero Emission Buildings (ZEB), photovoltaic solar energy systems are often installed. When the goal is to build a life cycle Zero Emission Building, all emissions come under scrutiny. Emissions from photovoltaic (PV) energy systems in Zero Emission Buildings have been shown to have a relative large share of material emissions. In this paper, we compare GHG emissions per kW h of electricity and greenhouse gas emission payback times (GPBT) for three residential PV systems in Zero Emission…
Published in
Journal papers
Influence of PV technology and system design on the emission balance of a net zero emission building concept
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract This paper presents an analysis of how the design of a photovoltaic (PV) system influences the greenhouse gas emission balance in a net zero emission building (nZEB). In a zero emission building, the emissions associated both with the energy required in the operation of the building (operational emissions) and the energy used to produce the building materials (embodied emissions) are offset by renewable energy generated on-site (avoided emissions). The analysis is applied to a nZEB concept for a single-family building, developed by the Norwegian Research Centre on Zero Emission Buildings. Previous analyses have shown that the installation of a…
Published in
Journal papers
Effect of storage and curing conditions at elevated temperatures on aerogel-incorporated mortar samples based on UHPC recipe
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract The effect of elevated temperature during storage and curing of ultra-high performance concrete (UHPC) formulated aerogel-incorporated mortar (AIM) samples was investigated. It was found that an effective aerogel loading of 60 vol% of total bulk volume was possible for producing AIM samples with suitable thermal and mechanical properties under optimized storing and curing conditions. AIM samples with compressive strengths of up to ≈19 MPa was achieved and the corresponding thermal conductivity was ≈0.4 W/(mK). For more insulating concrete, 70 vol% aerogel was needed and AIM samples with thermal conductivity as low as ≈0.1 W/(mK) were cast. In general, AIM samples with strengths of up…
Published in
Journal papers
Aerogel vs. argon insulation in windows: A greenhouse gas emissions analysis
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract The scope of this study is a comprehensive analysis of the greenhouse gas emissions from the partial substitution of triple-glazing units with argon gas (U-value of 0.79 W/m2 K) with double-glazing units with either monolithic aerogel (U-value of 0.65 W/m2 K) or granular aerogel (U-value of 0.31 W/m2d K). A residential building located near Oslo and fully upgraded with passive house solutions is used as a case study for this analysis. A cradle-to-site analysis is performed on the facade components. Two replacement schedules and three window-to-wall ratios are used to evaluate the differences in total emissions. Sensitivity analyses based on increasing the fraction of the…
Published in
Journal papers
Simple modelling procedure for the indoor thermal environment of highly-insulated buildings heated by wood stoves
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Published in
Journal papers
On the oversupply of heat to bedrooms during winter in highly insulated dwellings with heat recovery ventilation
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract The study presented in this paper originated from observations made regarding the thermal conditions during winter in highly insulated dwellings with mechanical ventilation with heat recovery (MVHR). Previous observations indicate an oversupply of heat to bedrooms and a successive extensive window ventilation, which leads to an increased space-heating demand. Detailed simulations were conducted to explain the causes for the observed thermal conditions and to elaborate improved solutions for heating and ventilation during winter. Various MVHR solutions and control strategies, as well as building design solutions, were investigated regarding their impact on the thermal conditions in bedrooms and on the…
Published in
Journal papers
Cost-optimal energy system design in Zero Energy Buildings with resulting grid impact: A case study of a German multi-family house
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract Zero Energy Buildings (ZEBs) are considered as one of the key elements to meet the Energy Strategy of the European Union. This paper investigates cost-optimal solutions for the energy system design in a ZEB and the subsequent grid impact. We use a Mixed Integer Linear (MILP) optimisation model that simultaneously optimises the building’s energy system design and the hourly operation. As a ZEB have onsite energy generation to compensate for the energy consumption, it is both importing and exporting electricity. The hourly time resolution identifies the factors that influence this import/export situation, also known as the building’s grid impact.…
Published in
Journal papers
Building integration of aerogel glazings
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract The recent building practices have shown that aerogel glazings can be used as a multifunctional building envelope component for different purposes. Nevertheless, the distinctive physical properties and energy performance of aerogel glazings suggest that building integration of aerogel glazings may create architectural challenges, aesthetic problems, as well as concerns on their durability and environmental impact, thus highlighting the importance of developing guidelines to regulate the use of aerogel glazings in the building sector. This study discusses various approaches for the building integration of aerogel glazings by presenting a number of successful examples; the advantages of integration are quantified and…
Published in
Journal papers
Avoiding snow and ice formation on exterior solar cell surfaces – a review of research pathways and opportunities
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Abstract Today energy-efficient and energy-harvesting buildings experience an ever-increasing interest and demand. Building integrated photovoltaics (BIPV) may in this respect represent a powerful and versatile tool for reaching the goal of zero energy and zero emission buildings. The BIPV systems replace the outer building envelope skin, thus serving simultanously as both a climate screen and a power source generating electricity. However, snow and ice formation on the exterior solar cell surfaces reduce their performance and may also lead to faster deterioration. Hence, if one could find a way to develop solar cells which were able to avoid snow and ice…
Published in
Journal papers
A Review of Materials Science Research Pathways and Opportunities for Building Integrated Photovoltaics
Authors:
Publication Year:
2016
Authors:
Publication Year:
2016
Published in
Journal papers
Energy performance assessment of a responsive building envelope component: Results from a numerical analysis
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Investigation of space-heating strategies in very low-energy houses using dynamic simulations: case of decentralized wood stoves approaches
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Investigation of the space-heating using wood stoves in very low-energy houses
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Fenestration solutions for zero emission renovation of dwellings
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
The actress concept. A new facade module for low energy buildings
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Façade Integration Typologies of Photovoltaics. Architecture and sustainable development.
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Nanomaterials for advanced window technologies
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Numerical Assessment of various PCM glazing system configurations. Energy performance assessment of a responsive building envelope component: Results from a numerical analysis.
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Solar Shading Systems and Thermal Performance of Windows in Nordic Climates
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Vacuum and Nanotechnologies for the Thermal Insulation Materials of Beyond Tomorrow - From Concept to Experimental Investigations
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Energy savings potential with electrochromic switchable glazing
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Strategies for renovation of single family dwellings from the 1980s towards zero energy levels
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Understanding Net Zero Energy Buildings: Evaluation of load matching and grid interaction indicators
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Qualitative user evaluation of energy efficient buildings – Case studies of six passive houses and zero-energy buildings
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Experimental and Numerical Investigations of Polystyrene Encapsulated Vacuum Insulation Panels- Heat Transfer Results
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Development of a CO2 emissions accounting method for Norwegian Zero Emission Buildings
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Energy-plus, zero energy and zero emission buildings denote some of the best buildings of today and the future with respect to energy efficiency and environmental impact. A zero emission building might be defined in different ways. Nevertheless, the main concept is that renewable energy sources produced or transformed at the building site have to compensate for CO2 emissions from operation of the building and for production, transport and demolition of all the building materials and components during the life cycle of the building. In order to fulfill this, CO2 emission data has to be made available and verified for traditional…
Published in
Conference papers
The Role of Product and System Interfaces in Designing Zero Emission Buildings
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Towards new configurations of work, life and energy? The role of the longue durée
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Cool roofing in cold climates: A contradiction or a potential for energy savings?
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Experimental Examination of the Thermal Transmittance of High Performance Window Frames and Comparison with Numerical Simulations
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
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…
Published in
Conference papers
Nano Technology and Possibilities for the Thermal Building Insulation Materials of Tomorrow
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
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…
Published in
Conference papers
Nanoelectrochromics with Applied Materials and Methodologies
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
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.
Published in
Conference papers
The Thermal Performance of Wall-Integrated Phase Change Material Panels – Hot Box Experiments
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
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…
Published in
Conference papers
Accelerated Ageing of Vacuum Insulation Panels
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
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…
Published in
Conference papers
Application of Vacuum Insulation Panels in Retrofitting of Timber Frame Walls – An Experimental and Theoretical Study of Moisture, Thermal Performance and Robustness
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
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…
Published in
Conference papers
Dynamic Solar Radiation Control in Buildings by Applying Electrochromic Materials
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
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…
Published in
Conference papers
Retrofitting of Timber Frame Walls by Application of Vacuum Insulation Panels and Investigations of Moisture Robustness
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Effect of Ageing on Service Life of Vacuum Insulation Panels
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
Published in
Conference papers
Accelerated Laboratory Ageing of Vacuum Insulation Panels
Authors:
Publication Year:
2011
Authors:
Publication Year:
2011
Published in
Conference papers
Proposal of a Norwegian ZEB definition: Storylines and Criteria
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
A clear and agreed definition of Zero Emission Building (ZEB) is yet to be achieved, both internationally and in Norway. However, it is understood that both the definition and the surrounding energy supply system will affect significantly the way buildings are designed to achieve the ZEB goal. Since the energy system in Europe is expected to change significantly in the coming decades, especially for electricity, it is indispensable to tie the definition of ZEB to possible scenarios on such development of the energy system. A scenario is defined as a combination of options chosen within a framework of different uncertain…
Published in
Conference papers
ZEB Definition: Assessing the Implications for Design
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
Conceptually a Zero Emission Building (ZEB) is a building with greatly reduced energy demand and able to generate electricity (or other carriers) from renewable sources in order to achieve a carbon neutral balance. However, a rigorous and agreed definition of ZEB is yet to come. A parallel paper in this conference explains how a formal and comprehensive ZEB definition can be based on the evaluation of certain criteria. These criteria are extensively discussed in ongoing projects, both in Norway and internationally. The objective of this paper is to focus on two of these criteria: energy performance and credits used to…
Published in
Conference papers
Criteria for Definition of Net Zero Energy Buildings
Authors:
Publication Year:
2010
Authors:
Publication Year:
2010
Published in
Conference papers