Publications

Abstract The net-zero emissions building (nZEB) performance is investigated for building operation (EO) and embodied emissions in materials (EE) for Norway's cold climate. nZEB concepts for new residential and office buildings are conceived in order to understand the balance and implications between operational and embodied emissions over the building's life. The main drivers for the CO2 equivalent (CO2e) emissions are revealed for both building concepts through a detailed emissions calculation. The influence of the CO2e factor for electricity is emphasized and it is shown to have significant impact on the temporal evolution of the overall CO2e emissions balance. The results…

Abstract The main objective of this paper is to contribute to the discussion on the role of Net Zero Energy Buildings (Net ZEBs) on future energy systems by the interplay between on-site generation and the building loads, often called load matching, and the resulting import/export interaction with the surrounding electricity grid, commonly named grid interaction. This investigation analyzes five case studies with high resolution data, three of which are based on real monitored buildings. The research aims at selecting and suggesting a limited set of quantitative indicators that: (a) can provide practical information for building as well as grid designers…

This thesis investigates how the occupant behavior influences the performance of residential net zero emission buildings (Net-ZEB) in cold climates such as in Norway, and proposes guidelines for better design, operation and control strategies. The thesis focuses on the occupant related variations in the internal gains and the domestic hot water use, and studies their influence on the building’s heating needs, its heating system performance and finally, its interaction with the onsite renewable generation and the grid. The application of the tightly insulated envelope in Net-ZEB significantly reduces the space heating needs. This increases the share of the occupant-related heat…

This report deals with how to define what a Zero Emission Building (ZEB) is with explanation and analysis of different parameters related to embodied emissions of CO2 equivalents. The report can be used as a guidance tool on how to assess embodied emissions, and also on what parameters should be evaluated in such an assessment. Different ambition levels for ZEBs may include life stages, operation, material, construction and end-of-life and can be documented according to EN 15978. Calculation procedures should include system boundaries, embodied emissions from materials, transport, the construction process and waste handling according to the ambition level. CO2 eq…


Et plusshus å lære i
Publication Year: 2014



ZEB sentralt på Ringdalskogen
Publication Year: 2014


Abstract The increasing energy consumption and its consequences have led to a major need for energy saving measures. Therefore, the passive house concept has been introduced. Passive houses have a low heating demand, so that it is theoretically possible to simplify the space heating distribution system by for example reduce the number of radiators. It has therefore been investigated if one central heat source can give sufficient thermal comfort in a whole housing unit. Research shows, with the use of simulations for Belgian climate, that thermal comfort can be obtained in the whole dwelling if the internal doors are open.…

Abstract During the uncontrolled consumption period the building sector has come to account one of the greatest proportions of greenhouse gas emissions and energy use in industrial countries. In this context, European countries have decided to address the environmental challenge by promoting the use of renewable energies and the implementation of low energy consumption requirements. For these reasons, zero emission buildings, which have a net zero annual energy demand, were regarded as a possible solution. And everything points to believe that they will continue to be crucial in a recent future. Consultants and contractors have shown the need towards a…

Abstract The research center of Zero Emissions Buildings (ZEB) has a goal of eliminating the greenhouse gas emissions associated with all phases of building development and use. This is achieved through more sustainable building construction and more efficient energy use. The Norwegian government has a similar goal of achieving zero energy buildings as a standard by 2020. This has led to proper investigation in technological solutions that can help to achieve these goals. In a net-ZEB perspective, combined heat and power (CHP) is considered as a potential energy supply solution for buildings. CHP is seen as an emerging technology which…

Abstract Thermal performance of the solar thermal systems are estimated using numerical methods and software since the solar processes are transitient in nature been driven by time dependent forcing functions and loads. The system components are defined with mathematical relationships that describe how components function. They are based on first principles (energy balances, mass balances, rate equations and equilibrium relationships) at one extreme or empirical curve fits to operating data from specific machines such as absorption chillers. The component models are programed i.e. they represent written subroutines which are simultaneously solved with the executive program. In this thesis for executive…

Abstract Because human population is growing at such a high rate, as well as the energy consumption per person, new ways of preserving and efficiently using available energy must be explored. Until new and abundant energy sources are found and means of their exploitation developed, research attention should be focused on finding ways of proper and safe use of what is nowadays available. In that sense, storage of thermal energy plays an important role both in heating and/or cooling applications, such as in residential or commercial buildings, and in industrial processes. Some of the technical solutions are based on phase…

Abstract Modern office buildings often have large glazed areas. Incident solar radiation can lead to large cooling demands during hot periods although the solar radiation can help reduce heating demands during cool periods.Previous studies have shown that large parts of the net energy demand of an office building is related to window heat loss and cooling demands induced by solar irradiance. In this article, the authors found that, even in what traditionally has been considered to be a heating-dominated climate, cooling demands dominate the net energy demand of an office building. Solar shading systems are vital to reduce the cooling…

Spesielt, nytt og lærerikt
Publication Year: 2014



Abstract This paper aimed to contribute to the discussion about the role of net zero-energy buildings (ZEBs) or nearly ZEBs in future energy systems, from the perspective of the resulting import/export interaction with the surrounding energy grid (commonly named grid interaction (GI)). This investigation analyses three buildings with measured data at sub-hourly time resolution. The goal of this paper was to quantify the effect of using high-resolution data (one or a few minutes) versus hourly resolution in the GI analysis of buildings with an on-site generation system. A limited set of quantitative GI indicators have been selected: the generation multiple,…

Abstract The design and assessment of net-zero buildings commonly focus exclusively on the operational phase, ignoring the embodied environmental impacts over the building life cycle. An analysis is presented on the consequences of integrating embodied impacts into the assessment of the environmental advantageousness of net-zero concepts. Fundamental issues needing consideration in the design process – based on the evaluation of primary energy use and related greenhouse gas emissions – are examined by comparing three net-zero building design and assessment cases: (1) no embodied impacts included, net balance limited to the operation stage only; (2) embodied impacts included but evaluated separately…

Abstract Glass represents an important and widely used building material, and crucial aspects to be addressed include thermal conductivity, visible light transmittance, and weight for windows with improved energy efficiency. In this work, by sintering monolithic silica aerogel precursors at elevated temperatures, aerogel glass materials were successfully prepared, which were characterized by low thermal conductivity [k ≈ 0.17–0.18 W/(mK)], high visible transparency (Tvis ≈ 91–96 % at 500 nm), low density (ρ ≈ 1.60–1.79 g/cm3), and enhanced mechanical strength (typical elastic modulus Er ≈ 2.0–6.4 GPa). These improved properties were derived from a series of successive gelation and aging steps during the desiccation of silica aerogels. The involved sol → gel → glass transformation was investigated by means…

I ZEB, og som en del av arbeidspakke 5 "Konsepter og strategier for nullutslippsbygg", er det gjennomført en studie av to energikonsepter for boligområdet Ådland i Bergen. Ådland ligger ved Flesland rett sør for Bergen sentrum. ByBo AS ønsker å bygge ut fra 500 – 800 boliger på området hvor både de enkelte boligene og området som helhet skal oppfylle kriterier for nullutslippsbygg. I ZEB er det definert ulike ambisjonsnivå for nullutslippsbygg. Den gjennomførte studien anbefaler et ambisjonsnivå ZEB-O som et gjennomsnitt for Ådland området. ZEB-O betyr at området skal være selvforsynt med energi, inklusive elektrisitet og varme, over et…

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