| 1. |
- Danielski, Itai, 1973-, et al.
(author)
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Air source heat pumps and their role in the Swedish energy system
- 2012
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In: Support your future today; Turning environmental problems into business opportunities.
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Conference paper (peer-reviewed)abstract
- Newly produced air source heat pumps can provide heat energy from outdoor air at temperature as low as -20°C. As a result they could be utilized during most days of the year even in the cold Nordic climates. The drawback of air source heat pumps is the reduction in efficiency as the outdoor air become colder, resulting in lower heat supply in times when it is most needed. Despite its inverse relationship between efficiency and outdoor temperature, air source heat pumps were installed in 57000 detached houses in Sweden during 2010 alone, which is 3% of the total detached houses stock. That makes air source heat pumps the most sold heating technology for detached houses in Sweden during 2010, 1.6 times more than the number of installations of ground source heat pump and 3 times more than the number of connections of detached houses to district heating during the same year. Similar trends can be found in other Nordic countries.This study compares the use of an air source heat pump with other existing commercial technologies in detached houses and analyzes the impacts on primary energy use, on final energy use, on electricity production and on costs benefits for house owners. It was found that converting existing electric heated Swedish detaches houses to district heating with biomass based CHP or bed-rock heat pump could reduce the use of resources, which could benefit Sweden as a society. Converting electric heated Swedish detaches houses to district heating or pellets stove could reduce power demand and level out the power demand load curve. That would benefit utilities of power supply as it could secure power supply. However cost effectiveness in one of most important drivers for house owners of detached houses to choose energy efficiency measures. For that reason house owners may most likely benefit by the installation of air-source heat pumps.
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| 2. |
- Danielski, Itai, et al.
(author)
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The impact of the shape factor on final energy demand in residential buildings in nordic climates
- 2012
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In: World Renewable Energy Forum, WREF 2012, Including World Renewable Energy Congress XII and Colorado Renewable Energy Society (CRES) Annual Conference. - 9781622760923 ; , s. 4260-4264
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Conference paper (other academic/artistic)abstract
- The shape factor of a building is the ratio between its envelope area and its volume. Buildings with a higher shape factor have a larger surface area in proportion to their volume, which results in larger heat losses in cold climates. This study analyzes the impact of the shape factor on the final energy demand by using five existing apartment buildings with different values of shape factor. Each building was simulated for twelve different scenarios: three thermal envelope scenarios and four climate zones. The differences in shape factor between the buildings were found to have a large impact and accounted for 10%-20% of their final energy demand. The impact of the shape factor was reduced with warmer climates and ceased with average outdoor temperature 11ºC-14ºC depending on the thermal envelope performance of the buildings.
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| 3. |
- Ekman, Anna, et al.
(author)
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Possibilities for sustainable biorefineries based on agricultural residues - A case study of potential straw-based ethanol production in Sweden
- 2013
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In: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 102, s. 299-308
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Journal article (peer-reviewed)abstract
- This study presents a survey of the most important techno-economic factors for the implementation of biorefineries based on agricultural residues, in the form of straw, and biochemical conversion into ethanol and biogas, together with production of electricity and heat. The paper suggests locations where the necessary conditions can be met in Sweden. The requirements identified are regional availability of feedstock, the possibility to integrate with external heat sinks, appropriate process design and the scale of the plant. The scale of the plant should be adapted to the potential, regional, raw-material supply, but still be large enough to give economies of scale. The integration with heat sinks proved to be most important to achieve high energy-efficiency, but it was of somewhat less importance for the profitability. Development of pentose fermentation, leading to higher ethanol yields, was important to gain high profitability. Promising locations were identified in the county of Ostergotland where integration with an existing 1st generation ethanol plant and district heating systems (DHSs) is possible, and in the county of Skane where both a significant, potential straw supply and integration potential with DHSs are available. (c) 2012 Elsevier Ltd. All rights reserved.
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| 4. |
- Gustavsson, Leif, et al.
(author)
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Life cycle primary energy analysis of residential buildings
- 2010
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In: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 42:2, s. 210-220
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Journal article (peer-reviewed)abstract
- The space heating demand of residential buildings can be decreased by improved insulation, reduced air leakage and by heat recovery from ventilation air. However, these measures result in an increased use of materials. As the energy for building operation decreases, the relative importance of the energy used in the production phase increases and influences optimization aimed at minimizing the Life cycle energy use. The Life cycle primary energy use of buildings also depends on the energy supply systems. In this work we analyse primary energy use and CO2 emission for the production and operation of conventional and low-energy residential buildings. Different types of energy supply systems are included in the analysis. We show that for a conventional and a low-energy building the primary energy use for production can be up to 45% and 60%, respectively, of the total, depending on the energy supply system, and with larger variations for conventional buildings. The primary energy used and the CO2 emission resulting from production are lower for wood-framed constructions than for concrete-framed constructions. The primary energy use and the CO2 emission depend strongly on the energy supply, for both conventional and low-energy buildings. For example, a single-family house from the 1970s heated with biomass-based district heating with cogeneration has 70% lower operational primary energy use than if heated with fuel-based electricity. The specific primary energy use with district heating was 40% lower than that of an electrically heated passive row house.
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| 5. |
- Gustavsson, Leif, et al.
(author)
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Life cycle primary energy use and carbon emission of an eight-storey wood-framed apartment building
- 2010
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In: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 42:2, s. 230-242
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Journal article (peer-reviewed)abstract
- In this study the life cycle primary energy use and carbon dioxide (CO2) emission of an eight-storey wood-framed apartment building are analyzed. All life cycle phases are included, including acquisition and processing of materials, on-site construction, building operation, demolition and materials disposal. The calculated primary energy use includes the entire energy system chains, and carbon flows are tracked including fossil fuel emissions, process emissions, carbon stocks in building materials, and avoided fossil emissions due to biofuel substitution. The results show that building operation uses the largest share of life cycle energy use, becoming increasingly dominant as the life span of the building increases. The type of heating system strongly influences the primary energy use and CO2 emission; a biomass-based system with cogeneration of district heat and electricity achieves low primary energy use and very low CO2 emissions. Using biomass residues from the wood products chain to substitute for fossil fuels significantly reduces net CO2 emission. Excluding household tap water and electricity, a negative life cycle net CO2 emission can be achieved due to the wood-based construction materials and biomass-based energy supply system. This study shows the importance of using a life cycle perspective when evaluating primary energy and climatic impacts of buildings.
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| 7. |
- Hamberg, Anna-Karin, 1964-, et al.
(author)
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Warfarin dose prediction in children using pharmacometric bridging : comparison with published pharmacogenetic dosing algorithms
- 2013
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In: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 69:6, s. 1275-1283
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Journal article (peer-reviewed)abstract
- PurposeNumerous studies have investigated causes of warfarin dose variability in adults whereas studies in children are limited both in numbers and size. Mechanism-based population modelling provides an opportunity to condense and propagate prior knowledge from one population to another. The main objectives with this study were to evaluate the predictive performance of a theoretically bridged adult warfarin model in children, and to compare accuracy in dose prediction relative to published warfarin algorithms for children.MethodAn adult population PK/PD-model for warfarin, with CYP2C9 and VKORC1 genotype, age and target INR as dose predictors, was bridged to children using allometric scaling methods. Its predictive properties were evaluated in an external dataset of children 0-18 years old, including comparison of dose prediction accuracy with three pharmacogenetics-based algorithms for children.ResultsOverall, the bridged model predicted INR response well in 64 warfarin treated Swedish children (median age 4.3 years), but with a tendency to over predict INR in children ≤ 2 years old. The bridged model predicted 20 of 49 children (41%) within ± 20% of actual maintenance dose (median age 7.2 years). In comparison the published dosing algorithms predicted 33-41% of the children within ± 20% of actual dose. Dose optimization with the bridged model based on up to three individual INR observations increased the proportion within ± 20% of actual dose to 70%.ConclusionA mechanism-based population model developed on adult data provides a promising first step towards more individualized warfarin therapy in children.
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| 8. |
- Joelsson, Anna, et al.
(author)
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Energy efficiency measures and conversion of fossil fuel boiler systems in a detached house
- 2010
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In: Energy efficiency. - : Springer Science and Business Media LLC. - 1570-6478 .- 1570-646X. ; 3:3, s. 223-236
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Journal article (peer-reviewed)abstract
- There is a large potential to reduce primary energy use and CO2 emissions from the Swedish building stock. Here detached houses heated by oil, natural gas or electric boilers were assessed. CO2 emissions, primary energy use and heating costs were evaluated before and after implementing house envelope measures, conversions to more efficient heating systems and changes to biomass fuel use. The study included full energy chains, from natural resources to usable heat in the houses. The aim was to evaluate the societal economic cost effectiveness of reducing CO2 emission and primary energy use by different combinations of changes. The results demonstrated that for a house using an electric boiler, a conversion to a heat pump combined with house envelope measures could be cost efficient from a societal economic perspective. If the electricity was based on biomass, the primary energy use was at the same time reduced by 70% and the CO2 emission by 97%. Large emission reductions were also seen for conversions from oil and gas boilers to a biomass-based system. However, for these conversions the heating cost increased, leading to a mitigation cost of around €50/tonne C avoided. The price of oil and natural gas greatly influenced the competitiveness of the alternatives. House envelope measures were more cost-effective for houses with electric boilers as the cost of energy for this system is high. The results are specific to a Swedish context, but also give an indication of the potential in other regions, such as northern European and large parts of North America, which have both a cold climate and a widespread use of domestic boilers.
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