Publications
Fiber reinforced hollow silica nanospheres for thermal insulation applications
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Publication Year:
2015
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2015
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Spectroscopic properties of hexagonal sodium tungstate nanorods
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2015
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2015
Abstract Sodium tungstate (Na-WO3) nanorods with typical diameters of 10-200 nm and lengths of several microns were prepared via hydrothermal synthesis. X-ray diffraction showed that the material crystallized in a hexagonal phase (space groupP6/mmm) with unit cell dimensions of a = 7.3166(8) Å and c = 3.8990(8) Å. The as-prepared Na-WO3 nanorods showed a distinctive visible-light-driven photochromism related to a proton-electron double injection process. The involved localstructural evolutions were monitored by Fourier transform infrared (FTIR) and Raman scattering spectroscopy. One diagnostic FTIR absorption at 585 cm-1 and one Raman band at 813 cm-1 were identified and assigned to the O-W-O stretching vibration. These two modes were strongly affected by the…
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Silver nanoparticles as low-emissivity coating materials for window glazing applications
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2015
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Publication Year:
2015
Abstract The potential of silver (Ag) nanoparticles as low emissivity (low-e) coating materials for window glazing applications has been discussed. Ag nanoparticles were prepared via a wet chemical method and applied on the surface of flat glass through spin coating. A mild heat treatment at 200°C was employed to achieve the low-e effect, which results in a total surface emissivity of about 0.015, compared to about 0.837 of the plain glass substrate. By applying such low-e coatings, the heat loss through a single-glazed window pane could be reduced by about 45% (U-value from 5.75 to 3.18 W/(m2K)).
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Modeling of the Indoor Thermal Comfort in Passive Houses heated by Wood Stoves
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2015
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2015
ABSTRACT Space-heating using wood stove is a popular solution in many European countries. Nevertheless, nominal powers of state-of-the-art stoves are oversized compared to the needs of highly-insulated building envelopes, such as passive houses. In this respect, a simplified wood stove model has been developed in order to investigate the thermal comfort using detailed dynamic simulations (e.g. TRNSYS) at an acceptable computational cost. A specific experimental setup has been developed to validate this modelling procedure, especially as regards the interaction between the stove and the building. The largest source of error appears to be the thermal stratification in the room where…
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Convective heat transfer between rooms in nordic passive houses
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2015
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2015
Abstract In highly-insulated buildings such as passive houses, the space-heating distribution subsystem can be simplified by reducing the number of heat emitters. In this context, the bi-directional flow through open doorways is known to be an efficient process to support the heat distribution between rooms. This process is therefore investigated using field measurements within a Norwegian passive house. The so-called large opening approximation proves to model fairly the mass flow rate, but also the convective heat transfer if the thermal stratification is accounted for. Furthermore, the discharge coefficient appears to be independent of the heater type and location in the room.
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Material research for zero emission buildings
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2015
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2015
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Conference presentations
Ombygging av eneboliger
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2015
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2015
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Experimental synthesis of hollow silica nanospheres for application as superinsulation in the buildings of tomorrow
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Publication Year:
2015
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Publication Year:
2015
ABSTRACT The path toward energy-efficient buildings with a low or zero carbon footprint, e.g. zero energy and zero emission buildings, involves the development of high-performance thermal insulation, aiming at reaching thermal conductivities far below 20 mW/(mK). Applying such superinsulation will allow the construction of relatively thin building envelopes yet maintaining a high thermal resistance, thus also increasing the architectural design possibilities. A vacuum insulation panel (VIP) represents a stateof-the-art thermal insulation solution with a thermal conductivity of typical 4 mW/(mK) in the pristine and non-aged condition. However, the VIPs have issues with fragility, perforation vulnerability, increasing thermal conductivity during time…
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Hybrid photovoltaic-thermal systems in buildings a review
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2015
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2015
Abstract This paper presents a review of projects where hybrid photovoltaic-thermal (PV/T) systems are used in buildings. PV/T systems convert solar radiation to electricity and heat simultaneously, in one module. The output of both electricity and heat suggests that the technology can be suited for use in buildings, especially when the available area for installation is limited. The market and research activities related to PV/T technology has increased in recent years. This article adds to existing reviews on PV/T technology by focusing on the building perspective. Different strategies for the use of PV/T in buildings are discussed, and examples of…
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Spectral and angular solar properties of a PCM-filled double glazing unit
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2015
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Publication Year:
2015
Abstract Background Phase change materials (PCMs) have been proposed as a means to increase the thermal inertia of glazing systems. These materials have optical features that need to be investigated and characterised in order to better understand the potential of these systems and to provide reliable data for numerical simulations. Methods The spectral and angular behaviour of different PCM glazing samples, characterised by different thicknesses of PCMs, were investigated by means of commercial spectrophotometer and by means of a dedicated optical test bed that includes a large integrating sphere with a diameter of 0.75 m. Such equipment was necessary because of…
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Journal papers
Influence of the occupant’s behavior on the heating needs and the energy system performance : A case of well-insulated detached houses in the cold climates
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2015
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2015
Abstract Modeling simplification related to occupant’s behavior is a major cause of gap between actual and model’s predicted energy use of buildings. This paper aims to identify those parameters of realistic occupants-related heat gains that actually cause this gap. The investigation therefore, systematically distinguishes the occupant behavior using three behavior parameters, namely: the occupancy behavior, the appliance use behavior and the family size. The effect of these parameters is investigated on a building for two different insulation standards using heat pump as energy supply system. The results identifies the occupancy patterns and the household size as two major parameters that explains a large portion…
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Journal papers
Silica aerogels - A multifunctional building material
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2015
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2015
Abstract Silica aerogels are a nanoporous material with extremely high porosity (up to ~99.8 %), low density (as low as ~0.005 g/cm3), and low thermal conductivity (~0.010–0.020 W/(mK)). Aerogels can also be made with a translucent or transparent state. These structural and functional features make aerogels a multifunctional material for many important applications. In this work, we discuss the perspective of aerogels as super insulation materials and window glazings in the building and construction sector. It shows that different research and development (R&D) strategies of aerogels shall be considered when aiming for different applications; reducing the manufacture cost, improving the…
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Synthesis and characterization of aerogel glass materials for window glazing applications
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2015
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2015
Summary This chapter reports an approach to enhance the mechanical strength of silica aerogels via densification. Although the loss of porosity and consequently the increase of thermal conductivity of silica aerogels represent drawbacks related to the densification process, a combination of enhanced mechanical performance and optical transparency indicates that the densificated silica aerogels may be used as new glass material for window glazing application. Preliminary experimental results indicate lightweight (density 1.8 g/cm3, compared to 2.5 g/cm3 for float glass) and thermal insulating (thermal conductivity k ≈ 0.18 W/(mK), compared to about 0.92 W/(mK) for float glass) aerogel glass materials with high visible transparency…
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Solutions and technologies for wood stoves in future's energy efficient residential buildings
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2015
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2015
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Vakuumisoleringspaneler i gamla byggnader
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2015
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2015
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Popular Science Articles
Identifying key design parameters of the integrated energy system for a residential Zero Emission Building in Norway
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Publication Year:
2015
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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…
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Ventilative cooling as a solution for highly insulated buildings in cold climate
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2015
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2015
AbstractNew and refurbished buildings have to relate to ever increasing standards regarding energy efficiency and energy consumption. This results in well insulated building envelopes with low air leakages offering reduced heating demands. One of the downsides of this is that these buildings are easily warmed up to such a degree that in order to sustain an acceptable indoor climate, removal of excess heat becomes a necessity. The removal of surplus heat is often done through means of mechanical cooling. However, energy consumption related to mechanical cooling is considered incompatible with achieving zero energy buildings (ZEB). As a response, the use…
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Energy use consequences of ventilative cooling in a ZEB residential building
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2015
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Publication Year:
2015
Abstract New buildings have to satisfy ever-tightening standards regarding energy efficiency and consumption. This results in higher insulation levels and lower air leakages that reduce heating demands. However, even at moderate outdoor temperatures these buildings are easily warmed up to such a degree that in order to ensure acceptable indoor environment quality, removal of excess heat becomes unavoidable. Use of electric energy related to mechanical cooling is considered incompatible with achieving zero energy buildings (ZEB). The use of ventilative cooling (VC) in combination with mechanical cooling means energy consumption reduction due to lower use of mechanical ventilation and cooling system.This…
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Hourly Electricity Load Modelling of non-residential Passive Buildings in a Nordic Climate
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2015
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2015
Abstract Detailed knowledge of electricity demand is essential for power system planning and operation. EUs 20-20-20 targets will increase the development of more energy efficient buildings as all new buildings shall be “nearly zero energy buildings” by 2020. The result from this ambition is that so-called passive buildings and nearly-net-zero-energy-buildings (nZEB), with lower energy demand, or even onsite power generation, will significantly change the way buildings are integrated in the power system. System operators must consequently prepare for changes in load profiles. However, the knowledge on the aggregated impact of nZEBs is so far limited because the actual number of such buildings is still very small. This paper contributes to this knowledge…
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Kunnskapsstatus – Fuktbufring I materialer og påvirkning på energibehov
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2015
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2015
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Reports
The suitability of air-heating in residential passive house buildings from the occupant’s point of view
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Publication Year:
2015
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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…
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Nullutslippsbygg er en klimaløsning
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2015
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2015
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Electrochromic Smart Windows for Dynamic Daylight and Solar Energy Control in Buildings
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Publication Year:
2015
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2015
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Books
Life cycle GHG emissions from a wooden load-bearing alternative for a ZEB office concept
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2015
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2015
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Reports
Nå bygger Forsvaret nullhus
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2013
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2013
Det nye administrasjonsbygget til forsvaret har et årlige beregnet energiforbruk på 16 kWh per kvadratmeter. Dette blir dermed et av landets mest energieffektive kontorbygg. Artikkel skrevet av Mari Gisvold Garathun.
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Media contributions
Presentasjon av skisser. Powerhouse-alliansens to første prosjekter
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2012
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2012
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Effektiv energibruk og energiforsyning/lokal produksjon i fremtidens bygninger
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2012
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2012
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Krav og forventninger til temperatur og luftkvalitet i fremtidens bygninger
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2012
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2012
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Fremtidens bygninger i et livsløpsperspektiv - materialbruk og CO2 utstlipp
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Publication Year:
2012
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2012
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Comfort and Energy Efficiency Recommendations for Net Zero Energy Buildings
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2010
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2010
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On the proper integration of wood stoves for the space-heating of passive houses
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2012
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2012
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Fremtidens bygninger – hvordan og hvorfor?
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2012
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2012
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Criteria for Definition of Net Zero Energy Buildings
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2010
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2010
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Effect of Ageing on Service Life of Vacuum Insulation Panels
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2010
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2010
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Accelerated Laboratory Ageing of Vacuum Insulation Panels
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2011
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2011
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Proposal of a Norwegian ZEB definition: Storylines and Criteria
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Publication Year:
2010
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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…
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ZEB Definition: Assessing the Implications for Design
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Publication Year:
2010
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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…
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From Passive House to Zero Emission Building: How much electricity generation is needed?
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Publication Year:
2010
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Publication Year:
2010
This paper shows how much electricity generation would be needed for a passive house to achieve a zero emission balance over the year, hence to become a Zero Emission Building, ZEB. The case study is based on the passive house apartment blocks built in 2008 in Løvåshagen, near Bergen, Norway, and the analysis focuses on the consequences of adopting different heating systems. With the carbon emission factors assumed, it is shown that the sole PV installation on the roof is generally not sufficient to generate all the electricity needed to achieve the ZEB balance. Possible integrations are the use of…
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Load Matching and Grid Interaction of Net Zero Energy Buildings
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2010
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2010
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Sustainable innovation in the building sector. A user perspective
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2010
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2010
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Towards zero emission buildings, settlements and cities. An introduction.
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2010
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2010
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Sustainable innovation in the building sector. An overview
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2010
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2010
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User evaluations of passive houses and low energy buildings – Literature Review and Further Research
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2010
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2010
This paper is based on a review of research that describes user experiences with different types of energy efficient buildings, focusing on indoor climate, technical operation, user attitudes, and general satisfaction. Energy efficient buildings are often rated better than conventional buildings on indoor climate, but when investigating more thoroughly, the users have different concerns. The varying results from the user evaluations reflect that the quality of the buildings differs. However, user concerns may also be a result of inappropriate use. Perceived personal control and sufficient information on operation and use is crucial for an overall positive experience of the building.…
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Domesticating the built environment
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2010
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2010
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Dealing with uncertainty in sustainable innovation: mainstreaming and substitution
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2010
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2010
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Sustainable Energy Supply for Passive House Developments. 4 Norwegian Case studies
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2010
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2010
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Towards a Zero Emission Built Environment in Norway
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2012
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2012
Pilot projects of sustainable climate-adapted architecture and the national research for carbon neutral buildings
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Marienlyst skole – Norges første passivhusskole
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2010
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2010
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Zero Energy Building – A Review of definitions and calculation methodologies
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2011
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2011
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Retrofitting of Timber Frame Walls by Application of Vacuum Insulation Panels and Investigations of Moisture Robustness
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Publication Year:
2011
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Publication Year:
2011
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