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  • 1.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Melting Characteristics and Morphology of Bottom Ash and Filter Ash of the Circulating Fluidized Bed Boiler2013In: 21st European Biomass Conference and Exhibition, Copenhagen, Danmark, 3rd-7th June, 2013, ETA-Florence Renewable Energies , 2013, 1189-1191 p.Conference paper (Refereed)
    Abstract [en]

    The aim of this work was to investigate the melting characteristics and morphology of filter ash and bottom ash with and without 7% of peat addition to the fuel of the circulating fluidized bed boiler. The samples were characterized by simultaneous thermal analysis (STA) and scanning electron microscope (SEM). The STA results indicate that the filter ash melts at 1140oC with 10 wt% of the mass loss and Bottom ash partially melts at 1170oC with below 2 wt% of the mass loss. The low melting point of the filter ash is due to the high concentration of the alkali metals in the filter ash. Similar trends were observed in the case of fly ash and bottom ash with peat admixture to the fuel. Furthermore the elementary analysis via scanning electron microscopy, coupled with energy-dispersive X-ray analysis showed that 7% of peat addition to the fuel does not significantly effect on the ash composition.

  • 2.
    Bonakdar, Farshid
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Cost-optimum analysis of building fabric renovation in a Swedish multi-story residential building2014In: Energy and Buildings, ISSN 0378-7788, Vol. 84, 662-673 p.Article in journal (Refereed)
    Abstract [en]

    In this study, we analysed the cost-optimum level of building fabric elements renovation in a multi-story residential building. We calculated final energy use for space heating of the building considering a wide range of energy efficiency measures, for exterior walls, basement walls, attic floor and windows. Different extra insulation thicknesses for considered opaque elements and different U-values for new windows were used as energy efficiency measures. We calculated difference between the marginal saving of energy cost for space heating and the investment cost of implemented energy efficiency measures, in order to find the cost-optimum measure for each element. The implications of building lifespans, annual energy price increase and discount rate on the optimum measure were also analysed. The results of the analysis indicate that the contribution of energy efficiency measures to the final energy use reduces, significantly, by increasing the thickness of extra insulation and by reducing the U-value of new windows. We considered three scenarios of business as usual (BAU), intermediate and sustainability, considering different discount rates and energy price increase. The results of this analysis suggest that the sustainability scenario may offer, approximately, 100% increase in the optimum thickness of extra insulation compare to BAU scenario. However, the implication of different lifespans of 40, 50 or 60 years, on the optimum measure appears to be either negligible or very small, depending on the chosen scenario. We also calculated the corresponding U-value of the optimum measures in order to compare them with the current Swedish building code requirements and passive house criteria. The results indicate that all optimum measures meet the Swedish building code. None of the optimum measures, however, meet the passive house criteria in BAU scenario. This study suggests that the employed method of building renovation cost-optimum analyses can be also applied on new building construction to find the cost-optimum design from energy conservation point of view.

  • 3.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hulteberg, Christain
    Kusar, Henrik
    Kungliga tekniska högskolan.
    A review of thermo-chemical conversion of biomass into biofuels: focusing on gas cleaning and up-grading process steps2017Report (Other (popular science, discussion, etc.))
    Abstract [en]

    It is not easy to replace fossil-based fuels in the transport sector, however, an appealing solution is to use biomass and waste for the production of renewable alternatives. Thermochemical conversion of biomass for production of synthetic transport fuels by the use of gasification is a promising way to meet these goals.

    One of the key challenges in using gasification systems with biomass and waste as feedstock is the upgrading of the raw gas produced in the gasifier. These materials replacing oil and coal contain large amounts of demanding impurities, such as alkali, inorganic compounds, sulphur and chlorine compounds. Therefore, as for all multi-step processes, the heat management and hence the total efficiency depend on the different clean-up units. Unfortunately, the available conventional gas filtering units for removing particulates and impurities, and also subsequent catalytic conversion steps have lower optimum working temperatures than the operating temperature in the gasification units.

    This report focuses on on-going research and development to find new technology solutions and on the key critical technology challenges concerning the purification and upgrading of the raw gas to synthesis gas and the subsequent different fuel synthesis processes, such as hot gas filtration, clever heating solutions and a higher degree of process integration as well as catalysts more resistant towards deactivation. This means that the temperature should be as high as possible for any particular upgrading unit in the refining system. Nevertheless, the temperature and pressure of the cleaned synthesis gas must meet the requirements of the downstream application, i.e. Fischer-Tropsch diesel or methanol.

    Before using the gas produced in the gasifier a number of impurities needs to be removed. These include particles, tars, sulphur and ammonia. Particles are formed in gasification, irrespective of the type of gasifier design used. A first, coarse separation is performed in one or several cyclone filters at high temperature. Thereafter bag-house filters (e.g. ceramic or textile) maybe used to separate the finer particles. A problem is, however, tar condensation in the filters and there is much work performed on trying to achieve filtration at as high a temperature as possible.

    The far most stressed technical barriers regarding cleaning of the gases are tars. To remove the tar from the product gas there is a number of alternatives, but most important is that the gasifier is operated at optimal conditions for minimising initial tar formation. In fluid bed and entrained flow gasification a first step may be catalytic tar cracking after particle removal. In fluid bed gasification a catalyst, active in tar cracking, may be added to the fluidising bed to further remove any tar formed in the bed. In this kind of tar removal, natural minerals such as dolomite and olivine, are normally used, or catalysts normally used in hydrocarbon reforming or cracking. The tar can be reformed to CO and hydrogen by thermal reforming as well, when the temperature is increased to 1300ºC and the tar decomposes. Another method for removing tar from the gas is to scrub it by using hot oil (200-300ºC). The tar dissolves in the hot oil, which can be partly regenerated and the remaining tar-containing part is either burned or sent back to the gasifier for regasification.

    Other important aspects are that the sulphur content of the gas depends on the type of biomass used, the gasification agent used etc., but a level at or above 100 ppm is not unusual. Sulphur levels this high are not acceptable if there are catalytic processes down-stream, or if the emissions of e.g. SO2 are to be kept down. The sulphur may be separated by adsorbing it in ZnO, an irreversible process, or a commercially available reversible adsorbent can be used. There is also the possibility of scrubbing the gas with an amine solution. If a reversible alternative is chosen, elementary sulphur may be produced using the Claus process.

    Furthermore, the levels of ammonia formed in gasification (3,000 ppm is not uncommon) are normally not considered a problem. When combusting the gas, nitrogen or in the worst case NOx (so-called fuel NOx) is formed; there are, however, indications that there could be problems. Especially when the gasification is followed by down-stream catalytic processes, steam reforming in particular, where the catalyst might suffer from deactivation by long-term exposure to ammonia.

    The composition of the product gas depends very much on the gasification technology, the gasifying agent and the biomass feedstock. Of particular significance is the choice of gasifying agent, i.e. air, oxygen, water, since it has a huge impact on the composition and quality of the gas, The gasifying agent also affects the choice of cleaning and upgrading processes to syngas and its suitability for different end-use applications as fuels or green chemicals.

    The ideal upgraded syngas consists of H2 and CO at a correct ratio with very low water and CO2 content allowed. This means that the tars, particulates, alkali salts and inorganic compounds mentioned earlier have to be removed for most of the applications. By using oxygen as the gasifying agent, instead of air, the content of nitrogen may be minimised without expensive nitrogen separation.

    In summary, there are a number of uses with respect to produced synthesis gas. The major applications will be discussed, starting with the production of hydrogen and then followed by the synthesis of synthetic natural gas, methanol, dimethyl ether, Fischer-Tropsch diesel and higher alcohol synthesis, and describing alternatives combining these methods. The SNG and methanol synthesis are equilibrium constrained, while the synthesis of DME (one-step route), FT diesel and alcohols are not. All of the reactions are exothermal (with the exception of steam reforming of methane and tars) and therefore handling the temperature increase in the reactors is essential. In addition, the synthesis of methanol has to be performed at high pressure (50-100 bar) to be industrially viable.

    There will be a compromise between the capital cost of the whole cleaning unit and the system efficiency, since solid waste, e.g. ash, sorbents, bed material and waste water all involve handling costs. Consequently, installing very effective catalysts, results in unnecessary costs because of expensive gas cleaning; however the synthesis units further down-stream, especially for Fischer-Tropsch diesel, and DME/methanol will profit from an effective gas cleaning which extends the catalysts life-time. The catalyst materials in the upgrading processes essentially need to be more stable and resistant to different kinds of deactivation.

    Finally, process intensification is an important development throughout chemical industries, which includes simultaneous integration of both synthesis steps and separation, other examples are advanced heat exchangers with heat integration in order to increase the heat transfer rates. Another example is to combine exothermic and endothermic reactions to support reforming reactions by using the intrinsic energy content. For cost-effective solutions and efficient application, new solutions for cleaning and up-grading of the gases are necessary.

  • 4.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Odenbrand, Ingemar
    Lund University .
    Poisoning of SCR Catalysts used in Municipal Waste Incineration Applications2017In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 60, no 17-18, 1306-1316 p.Article in journal (Refereed)
    Abstract [en]

    A commercial vanadia, tungsta on titania SCRcatalyst was poisoned in a side stream in a waste incinerationplant. The effect of especially alkali metal poisoningwas observed resulting in a decreased activity at long timesof exposure. The deactivation after 2311 h was 36% whilethe decrease in surface area was only 7.6%. Thus the majorcause for deactivation was a chemical blocking of acidicsites by alkali metals. The activation–deactivation modelshowed excellent agreement with experimental data. Themodel suggests that the original adsorption sites, fromthe preparation of the catalyst, are rapidly deactivated butare replaced by a new population of adsorption sites dueto activation of the catalyst surface by sulphur compounds(SO2, SO3)in the flue gas.

  • 5. Bäck, Andreas
    et al.
    Grubbström, Jörgen
    Ecke, Holger
    Pettersson, Jens
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Operation of an Electroctrostatic Precipitator at a 30 MWth oxyfuel plant2011Conference paper (Other academic)
    Abstract [en]

    The performance of a full-scale ESP was studied at the Vattenfall AB oxyfuel pilot plant in SchwarzePumpe. The lignite-fired boiler has a 30 MWth top-mounted pulverized coal burner and was operated under conventional air combustion as well as oxyfuel combustion. The ESP was operated with varying numbers of fields in service and at different current/voltage settings. Particle number size distributionsdownstream the ESP were established on-line in the size range 0.015-10 μm, using an electrical mobility spectrometer and an aerodynamic particle sizer. The particle size distribution at oxyfuel operation was qualitatively very similar to the results obtained for air-firing. Gravimetric measurementsof total fly ash concentration showed outlet emissions below 5 mg/Nm3 when the ESP was operatedwith two fields in service at oxyfuel conditions.

  • 6.
    Carlsson, Bo
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Meir, Michaela
    Aventa AS, Norway.
    Rekstad, John
    Aventa AS, Norway.
    Preiss, Dieter
    AEE-INTEC, Austria.
    Ramschak, Thomas
    AEE-INTEC, Austria.
    Replacing traditional materials with polymeric materials in solar thermosiphon systems: Case study on pros and cons based on a total cost accounting approach2016In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 125, 294-306 p.Article in journal (Refereed)
    Abstract [en]

    The pros and cons of replacing traditional materials with polymeric materials in solar thermosiphon systems were analysed by adopting a total cost accounting approach.

    In terms of climatic and environmental performance, polymeric materials reveal better key figures than traditional ones like metals. In terms of present value total cost of energy, taking into account functional capability, end user investment cost, O&M cost, reliability and climatic cost, the results suggest that this may also be true when comparing a polymeric based thermosiphon system with a high efficient thermosiphon system of conventional materials for DHW production in the southern Europe regions. When present values for total energy cost are assessed for the total DHW systems including both the solar heating system and the auxiliary electric heating system, the difference in energy cost between the polymeric and the traditional systems is markedly reduced.

    The main reason for the difference in results can be related to the difference in thermal performance between the two systems. It can be concluded that the choice of auxiliary heating source is of utmost importance for the economical competiveness of systems and that electric heating may not be the best choice.

  • 7.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effect of energy efficiency requirements for residential buildings in Sweden on lifecycle primary energy use2014In: Energy Procedia, ISSN 1876-6102, Vol. 61, 1183-1186 p.Article in journal (Refereed)
    Abstract [en]

    In this study we analyze the lifecycle primary energy use of a wood-frame apartment building designed to meet the current Swedish building code or passive house criteria, and heated with district heat or bedrock heat pump. We employ a lifecycle perspective methodology and determine the production, operation and end-of-life primary energy use of the buildings. We find that the passive house requirement strongly reduces the final energy use for heating compared to the current Swedish building code. However, the primary energy use is largely determined by the energy supply system, which is generally outside the mandate of the building standards. Overall, buildings with district heating have lower life-cycle primary energy use than alternatives heated with heat pump. The primary energy for production is small relative to that for operation, but it is more significant as the energy-efficiency standard of building improves and when efficient energy supply is used. Our results show the importance of a system-wide lifecycle perspective in reducing primary energy use in the built environment. A life cycle primary energy perspective is needed to minimize overall primary energy use, and future building energy-efficiency standards may reflect the full energy use during a building's life cycle. This could include primary energy implications for production, operation and end-of-life of buildings.

  • 8.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Energy use and overheating risk of Swedish multi-storey residential buildings under different climate scenarios2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 97, 534-548 p.Article in journal (Refereed)
    Abstract [en]

    In this study, the extent to which different climate scenarios influence overheating risk, energy use and peak loads for space conditioning of district heated multi-storey buildings in Sweden are explored. Furthermore, the effectiveness of different overheating control measures and the implications of different electricity supply options for space cooling and ventilation are investigated. The analysis is based on buildings with different architectural and energy efficiency configurations including a prefab concrete-frame, a massive timber-frame and a light timber-frame building. Thermal performance of the buildings under low and high Representative Concentration Pathway climate scenarios for 2050–2059 and 2090–2099 are analysed and compared to that under historical climate of 1961–1990 and recent climate of 1996–2005. The study is based on a bottom-up methodology and includes detailed hour-by-hour energy balance and systems analyses. The results show significant changes in the buildings’ thermal performance under the future climate scenarios, relative to the historical and recent climates. Heating demand decreased significantly while cooling demand and overheating risk increased considerably with the future climate scenarios, for all buildings. In contrast to the cooling demand, the relative changes in heating demand of the buildings under the future climate scenarios are somewhat similar. The changes in the space conditioning demands and overheating risk vary for the buildings. Overheating risk was found to be slightly higher for the massive-frame building and slightly lower for the light-frame building.

  • 9.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Bonakdar, Farshid
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effects of future climate change scenarios on overheating risk and primary energy use for Swedish residential buildings2014In: Energy Procedia, ISSN 1876-6102, Vol. 61, 1179-1182 p.Article in journal (Refereed)
    Abstract [en]

    In this study we use dynamic computer simulation modelling to investigate the potential impact of future climate change scenarios on the risk of overheating and annual primary energy requirements for space heating and cooling of residential buildings in Växjö, Sweden. The buildings are designed to the energy efficiency level of conventional or passive house, and are assumed to be heated with district heating and cooled with mechanical cooling system. We compare different climate change scenarios to a baseline which represents the climate data of Växjö for 1996-2005. The climate change scenarios are based on projected temperature changes under the representative concentration pathways (RCP) 4.5 and 8.5 scenarios. The result shows that the risk of overheating increases under the climate change scenarios. Furthermore space heating demand is reduced and cooling demand is increased for the analyzed buildings, and the changes are proportionally more significant for the passive compared to the conventional building.

  • 10.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Tettey, Uniben Yao Ayikoe
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    On input parameters, methods and assumptions for energy balance and retrofit analyses for residential buildings2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 137, 76-89 p.Article in journal (Refereed)
    Abstract [en]

    In this study we explore key parameter values, methods and assumptions used for energy balance modelling of residential buildings in the Swedish context and analyse their effects on calculated energy balance of a typical multi-storey building from 1970s and on energy savings of energy efficiency retrofit measures. The parameters studied are related to microclimate, building envelope, occupancy behaviour, ventilation, and heat gains from electric appliances and persons. Our study shows that assumed indoor air temperature, internal heat gains and efficiency of ventilation heat recovery units have significant effect on the simulated energy performance of the studied building and energy efficiency measures. Of the considered microclimate parameter values and assumptions, the outdoor temperature, ground solar reflection and window shading have significant impact on the simulated space heating and cooling demands. On the contrary, the simulated energy performances are less affected by the variations in air pressure outside and the percentage of wind load that hits the building. We found that input data and assumptions used for energy balance calculations and energy saving analyses vary significantly in the Swedish context. These result in significantly different calculated final energy performance of buildings and energy efficiency measures. To inform accurate analysis of energy performance of building and energy saving measures, input parameters used in simulation models need to be appropriate.

  • 11.
    Einvall, Jessica
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Albertazzi, Simone
    Bologna University, Italy.
    Hulteberg, Christian
    Catator AB.
    Malik, Azhar
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Basile, Francesco
    Bologna University, Italy.
    Larsson, Ann-Charlotte
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Brandin, Jan
    Catator AB.
    Sanati, Mehri
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Investigation of reforming catalyst deactivation by exposure to fly ash from biomass gasification in laboratory scale2007In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 21, no 5, 2481-2488 p.Article in journal (Refereed)
    Abstract [en]

    Production of synthesis gas by catalytic reforming of product gas from biomass gasification can lead to catalyst deactivation by the exposure to ash compounds present in the flue gas. The impact of fly ash from biomass gasification on reforming catalysts was studied at the laboratory scale. The investigated catalyst was Pt/Rh based, and it was exposed to generated K2SO4 aerosol particles and to aerosol particles produced from the water-soluble part of biomass fly ash, originating from a commercial biomass combustion plant. The noble metal catalyst was also compared with a commercial Ni-based catalyst, exposed to aerosol particles of the same fashion. To investigate the deactivation by aerosol particles, a flow containing submicrometer-size selected aerosol particles was led through the catalyst bed. The particle size of the poison was measured prior to the catalytic reactor system. Fresh and aerosol particle exposed catalysts were characterized using BET surface area, XRPD (X-ray powder diffraction), and H2 chemisorption. The Pt/Rh catalyst was also investigated for activity in the steam methane reforming reaction. It was found that the method to deposit generated aerosol particles on reforming catalysts could be a useful procedure to investigate the impact of different compounds possibly present in the product gas from the gasifier, acting as potential catalyst poisons. The catalytic deactivation procedure by exposure to aerosol particles is somehow similar to what happens in a real plant, when a catalyst bed is located subsequent to a biomass gasifier or a combustion boiler. Using different environments (oxidizing, reducing, steam present, etc.) in the aerosol generation adds further flexibility to the suggested aerosol deactivation method. It is essential to investigate the deactivating effect at the laboratory scale before a full-scale plant is taken into operation to avoid operational problems.

  • 12.
    Gustavsson, Leif
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Truong, Nguyen Le
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effects of different bioenergy pathways on primary energy efficiency, climate mitigation and energy system integration2015In: The 10th Conference on Sustainable Development of Energy, Water and Environment Systems – SDEWES 2015. September 27- October 3, 2015, Dubrovnik, Croatia, 2015Conference paper (Refereed)
    Abstract [en]

    Woody biomass is an important renewable energy resource that can be used directly or indirectly in the electricity, heat and transport sectors. Different technologies and conversion pathways can be used to convert woody biomass to supply different types of energy services. The primary energy and climate implications of bioenergy systems depend on which conversion technologies and pathways are used to produce the energy services, as well as how the services would have been supplied without the bioenergy system. Here, we focus on bioenergy for transportation in the context of a total renewable-based energy system. We contrast two different pathways: (i) biomotor fuel production in stand-alone plants and (ii) bioelectricity production in standalone plants and district heating systems with CHP plants and heat storage capacity for electric and plug-in hybrid vehicles. We quantify the primary energy use and the instantaneous biogenic CO2 of the two alternatives, per km of driving distance. We consider both commercially available technologies and emerging technologies for biomass-based conversion systems. Furthermore, for the two alternatives we discuss potential benefits of integration between the electricity, heating and transport sectors, to enable a better use of infrastructure. The results show that primary energy use and instantaneous biogenic CO2 emission vary strongly between the alternatives. The primary energy efficiency is much higher and gives less instantaneous biogenic CO2 emission for electric and plug-in hybrid vehicles compared to vehicles using biomotor fuels. Furthermore, the potential integration benefits between the electricity, heating and transport sectors are much larger due to the integration potential of heat storage capacity in DHS and battery storage capacity in electric and plug-in hybrid vehicles, as well as an improved overall integration capacity between the sectors. This study suggests that use of biomass should be considered in the context of the overall energy system, and in relation to the development of energy conversion technologies and integration potential between different energy sectors, to find primary energy efficient alternatives giving climate benefits in both a short- and long-term perspective.

  • 13.
    Haus, Sylvia
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Sathre, Roger
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Climate mitigation comparison of woody biomass systems with the inclusion of land-use in the reference fossil system2014In: Biomass and Bioenergy, ISSN 0961-9534, Vol. 65, 136-144 p.Article in journal (Refereed)
    Abstract [en]

    While issues of land-use have been considered in many direct analyses of biomass systems, little attention has heretofore been paid to land-use in reference fossil systems. Here we address this limitation by comparing forest biomass systems to reference fossil systems with explicit consideration of land-use in both systems. We estimate and compare the time profiles of greenhouse gas (GHG) emission and cumulative radiative forcing (CRF) of woody biomass systems and reference fossil systems. A life cycle perspective is used that includes all significant elements of both systems, including GHG emissions along the full material and energy chains. We consider the growth dynamics of forests under different management regimes, as well as energy and material substitution effects of harvested biomass. We determine the annual net emissions of CO2, N2O and CH4 for each system over a 240-year period, and then calculate time profiles of cRF as a proxy measurement of climate change impact. The results show greatest potential for climate change mitigation when intensive forest management is applied in the woody biomass system. This methodological framework provides a tool to help determine optimal strategies for managing forests so as to minimize climate change impacts. The inclusion of land-use in the reference system improves the accuracy of quantitative projections of climate benefits of biomass-based systems. (c) 2014 Elsevier Ltd. All rights reserved.

  • 14.
    Haus, Sylvia
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Sathre, Roger
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Greenhouse Gas Emission Comparison of Woody Biomass Systems with the Inclusion of Land-use in the Reference Fossil System2013In: 21st European Biomass Conference & Exhibition, Copenhagen, June 3-7, 2013, ETA-Florence Renewable Energies, , 2013, 1794-1799 p.Conference paper (Refereed)
    Abstract [en]

    While issues of land-use have been considered in many analyses of biomass systems, little attention has heretofore been paid to land-use in reference fossil systems. In this study we address this limitation by comparing forest biomass systems to reference fossil systems with explicit consideration of land-use in both systems. We estimate and compare the time profiles of greenhouse gas (GHG) emission and cumulative radiative forcing (CRF) of woody biomass systems and reference fossil systems. A life cycle perspective is used that includes all elements of both systems and all GHG emissions along the full material and energy chains. We consider the growth dynamics of forests under different management regimes, as well as energy and material substitution effects. We determine the annual net emissions of CO2, N2O and CH4 for each system over a 240-year period. We then calculate time profiles of CRF as a proxy for climate change impacts. The results show greatest CRF reduction when fertilized forest management is applied in the woody biomass system. The results show the relevance of including land use options in both the biomass and the fossil system to accurately determine the climate impacts and benefits of forest management and product use.

  • 15.
    Hemström, Kerstin
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Contractor Perceptions of Very Energy Efficient New Multi-Story Residential Buildings2014In: World Sustainable Building 2014 Barcelona Conference: Sustainable Buildings: Results ; Are We Moving as Quickly as We Should? It's Up to Us!, GBCe , 2014Conference paper (Refereed)
    Abstract [en]

    To facilitate design of policies and strategies which aim to promote a sustainable development of the built environment, a deeper understanding of factors influencing the decisions taken in construction projects is needed. This study investigates Swedish contractors’ perceptions of the new-build of very energy efficiency multi-storey residential buildings (e.g. passive houses). The results of interviews with twenty selected contracts managers disclose several perceived disadvantages and risks associated with such buildings which influence the interest to invest in high energy efficiency. These include several cost and market-related issues as well as issues relating to the performance of the buildings. Without market intervention it seems unlikely that very energy efficient multi-storey residential buildings will diffuse to any substantial degree within the Swedish construction industry.

  • 16.
    Hemström, Kerstin
    et al.
    Mittuniversitetet.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Swedish private forest owners’ perceptions and intentions with respect to adopting exotic tree species2013In: European Journal of Forest Research, ISSN 1612-4669, E-ISSN 1612-4677, Vol. 132, no 3, 433-444 p.Article in journal (Refereed)
    Abstract [en]

    Swedish forest growth can be increased through intensive forestry practices, enabling an increased use of forest biomass for climate-change mitigation. However, the diffusion of such practices depends on the forest owners’ adoption of them. We study Swedish private forest owners’ perceptions and intentions with respect to increasing forest growth by adopting exotic tree species. The results of a mail-in questionnaire survey show that although a majority of forest owners desire increasing forest growth, most owners have only a basic understanding of exotic tree species and a smaller proportion is interested in adopting them. The intention to adopt exotics seems to depend on the perceived performance of the species with respect to the economic aspects of forest management rather than on environmental or recreational concerns. Whereas a knowledge gap among the private forest owners regarding how to increase forest growth is implied, forest owners with higher self-rated knowledge of forestry and exotics have stronger intentions to adopt such species.

  • 17.
    Hjort, Åke
    et al.
    Euronom AB.
    Carlsson, Bo
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Method and Device for heating a building using a solar collector2014Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Method when heating a building with solar collectors comprising also a heat pump and energy storage using phase change materials. The invention is charaterized in that the energy storage system comprises to two containers, one placed indoors, where the phase change material has a melting point between 19 and 30 degrees Celsius, and a second container located outdoors and buried in the ground, where the phase change material has a conversion temperature which corresponds to or is lower  than the mean temperature of the ground surrounding the container.

  • 18.
    Joelsson, Jonas
    et al.
    Mittuniversitetet.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Reductions in greenhouse gas emissions and oil use by DME (di-methyl ether) and FT Fischer-Tropsch) diesel production in chemical pulp mills2012In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 39, no 1, 363-374 p.Article in journal (Refereed)
    Abstract [en]

    Using energy systems analysis, we examine the potential to reduce CO2 emissions and oil use by integrating motor biofuel production with pulp mills. BLG-DME (black liquor gasification with di-methyl ether production) is compared with solid biomass gasification with BIG-Fr (solid biomass gasification with Fischer-Tropsch fuel production). The studied systems are expanded with stand-alone production of biomass-based electricity and motor fuel so that they yield the same functional unit in terms of motor fuel and electricity as well as pulp or paper product, in order to facilitate comparison. More motor biofuel can be produced in integration with the studied mills with BLG-DME than with BIG-FT because the black liquor flow is large compared with other fuel streams in the mill and the integration potential for BIG-FT is limited by the mill's heat demand. When both systems are required to produce the same functional unit, the BLG-DME system achieves higher system efficiency and larger reductions in CO2 emissions and oil use per unit of biomass consumed. In general, integration of motor biofuel production with a pulp mill is more efficient than stand-alone motor biofuel production. Larger reductions in CO2 emissions or oil use can, however, be achieved if biomass replaces coal or oil in stationary applications.

  • 19.
    Joelsson, Jonas
    et al.
    Mittuniversitetet.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Swedish biomass strategies to reduce CO2 emission and oil use in an EU context2012In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 43, no 1, 448-468 p.Article in journal (Refereed)
    Abstract [en]

    Swedish energy strategies for transportation, space heating and pulp industries were evaluated with a focus on bioenergy use. The aims were to 1) study trade-offs between reductions in CO2 emission and oil use and between Swedish reductions and EU reductions, 2) compare the potential contributions of individual reduction measures, 3) quantify the total CO2 emission and oil use reduction potentials. Swedish energy efficiency measures reduced EU CO2 emission by 45-59 Mt CO2/a, at current biomass use and constant oil use. Doubling Swedish bioenergy use yielded an additional 40 Mt CO2/a reduction. Oil use could be reduced, but 36-81 kt of reductions in CO2 emission would be lost per Pi of oil use reduction. Swedish fossil fuel use within the studied sectors could be nearly eliminated. The expansion of district heating and cogeneration of heat with a high electricity yield were important measures. Plug-in hybrid electric cars reduced CO2 emission compared with conventional cars, and the difference was larger with increasing oil scarcity. The introduction of black liquor gasification in pulp mills also gave large CO2 emission reduction. Motor fuel from biomass was found to be a feasible option when coal is the marginal fuel for fossil motor fuel production. (C) 2012 Elsevier Ltd. All rights reserved.

  • 20.
    Johansson, Kristian
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustafsson, Filip
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Analys av förluster i småskaligt fjärrvärmenät: En studie för Lessebo Fjärrvärme2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna studie analyserar de rapporterat höga förlusterna i ett småskaligt fjärrvärmenät i Lessebo där styrkort för år 2013 redovisar förluster på 38 %. Genom att med en kvantitativ metod beräkna de värmeförluster som sker genom värmeledning i rörnätet görs en bedömning om rörnätets utformning är källan till de höga förlusterna eller ej. Studien ger indikationer på att fjärrvärmenätet i Lessebo är bra utformat och det därför finns oidentifierade orsaker till de höga förlusterna. Utöver redogörande av värmeförluster ger rapporten även kunskaper om fjärrvärmebranschens flera tekniker, begränsningar och framtida utvecklingsmöjligheter.

  • 21.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Morgalla, Mario
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Study on char fragmentation during biomass gasification in bubbling fluidized bed2015In: 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, ETA-Florence Renewable Energies , 2015, 652-655 p.Conference paper (Refereed)
    Abstract [en]

    In this work a bench scale bubbling fluidized bed gasifier was built to work with an aerosol sampling and measuring system in order to study char fragmentation phenomenon during biomass gasification process. Both barbeque char and wood pellets were gasified in CO2 (20 vol.%) -N2 mixture and steam (30 vol.%)-N2 mixture, respectively. An aerodynamic particle sizer (APS) was used to measure fragmented char particles during the whole gasification process. For the wood pellet gasification case, major fragmentation was observed during the devolatilization stage, which should be attributed to the combined effect of primary fragmentation and attrition. The aerodynamic diameter of those elutriable particles which can be measured by the current system was in the range of 0.5-8 µm. During the char gasification stage, a distinct mode of char fragments was produced in the size range of 1-7 µm in either case. The total mass concentration of elutriable particles gradually increased when gasification of char started, and then decreased while the reaction approached completion.

  • 22.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Further development and application of aerosol-based method for on-line investigation of char reactivity in steam2013In: Proceedings for 21st European Biomass Conference and Exhibition, ETA-Florence Renewable Energies , 2013, 875-878 p.Conference paper (Refereed)
    Abstract [en]

    Wood char was prepared from wood pellets under controlled pyrolysis conditions. The gasification kinetics for wood char in 33 vol% steam was established in the temperature range from 800ºC to 1300ºC by the combination of thermogravimetric analysis (TGA) and a novel aerosol-based method. The aerosol method was further developed and demonstrated successfully for generating, transporting and gasifying the suspended char particles (0.5-10 µm) in the steam atmosphere at high temperature up to 1300ºC. A tapered element oscillating microbalance (TEOM) was used to measure the change of mass concentrations of particles in the carrier gas, before and after gasification. The activation energy was 155 kJ·mol-1 for wood char with the pre-exponential factor of 3.56×104. This method can be potentially applied to on-line measure the reactivity of char particles directly in hot gas from the gasifier.

  • 23.
    Lindberg, Marcus
    et al.
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Johansson, Per
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Joélius, Mikael
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    LNG - Framtidens fartygsbränsle: Vad är det som hämmar utvecklingen av LNG-drift i Sverige?2015Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Shipping today faces stricter environmental requirements for pollution from vessels. Shipping companies have started to look for alternative fuel to achieve better environmental outcome. The Baltic Sea today is a major trading area for shipping . On 1 of January 2015 a new set of brand new and stricter regulation is getting implemented and these regulations are called SECA. Vessel running on LNG as an alternative fuel is today discussed extensively within the Swedish Maritime forum where emissions of NOx, sulfur and particles are less recipients than in heavy fuel oil (HFO). One of todays problems with a LNG distribution in Sweden are that the infrastructure is incomplete and outdated. This report has been built upon qualitative interviews with important actors within the Swedish maritime forum and also what impedes the development of the LNG’s infrastructure. The outcome of the interviews showed that the development has been slowed down because none within the Swedish martime forum have dared to take the first step. The ports does not want to develop terminals when there is no market demand and the shipping companies does not want to build vessel that runs on LNG when there is no market for distribution. Swedish governments involvement has been very weak, almost non-existing. There are also gaps in the Swedish regulations and restrictions of LNG cargo handling. This is aslo one of the factors that the development of LNG has been impeded. 

  • 24.
    Morgalla, Mario
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Characterization Of Particulate Matter In Biomass Gasification2015In: Proceedings for the 23rd European Biomass Conference and Exhibition / [ed] I. Obernberger, D. Baxter, A.Grassi, P.Helm, ETA-Florence Renewable Energies , 2015, 664-667 p.Conference paper (Refereed)
    Abstract [en]

    The purpose of this work is to examine the potential of monitoring heavy tar compounds contained in the product gas of a biomass gasifier. The hot product gas from atmospheric indirect bubbling fluidized bed gasification of wood pellets was extracted. The sampling and conditioning system consisted of a high-temperature dilution probe, a primary thermodenuder and a secondary thermodenuder. Online and semi-online instruments were used to characterize the aerosol in terms of number size distribution and particle mass concentration. The fine mode (mobility equivalent diameter db < 150 nm) was found to mainly consist of heavy tar compounds. An Electrical low­pressure impactor (ELPI) was used to measure this mode with a time resolution of 1 second and thus showed the potential for online measurements of heavy tar.

  • 25.
    Munkacsi, Noemi
    et al.
    Budapest University of Technology and Economics, Hungary.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    The role of social influence in the end customer purchasing decisions on the heat market2017In: Proceedings from eceee Summer Studies, European Council for an Energy Efficient Economy (ECEEE), 2017Conference paper (Refereed)
    Abstract [en]

    The aim of this paper is to examine the role of social influence on the end customer behaviour in the purchase of heating products in residential segment. The study is based on interviews and questionnaire survey of homeowners in Hungary in 2013. Respondents are open to learn about diverse innovative heating technologies, energy types and diverse heating fuels irrespective of any purchase intention. They plan their purchase based on deliberate considerations rather than facing an emergency heating appliance breakdown. Furthermore, influence of the social environment prevails at the diverse stages of the purchase process. End customers actively conduct social search (family, friends, neighbours, colleagues, other customers with purchase experience over the Internet, etc.) besides the influencing role of the installer.

  • 26.
    Nilsson, Bengt
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nilsson, Daniel
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Distribution of logging residues at the clear-felled site after fuel adapted logging operations2015In: Papers of the 23rd European Biomass Conference: Setting the course for a biobased economyExtracted from the Proceedings of the International Conference held in Viennna, Asutria1-4 June 2015 / [ed] Obernberger I, Baxter D, Grassi A, Helm P, ETA-Florence Renewable Energies , 2015, 270-272 p.Conference paper (Refereed)
    Abstract [en]

    During extraction of logging residues previous studies in Sweden have shown that up to 50% of the available logging residues will not reach the energy-conversion site. The remaining potential of the logging residues are therefore lost by handling either at the clear-felled site, during transportation or due to decomposition. An outtake of 100% is not possible or desired, since the Swedish Forest Agency recommends that at least 20% of the logging residues should be left at the clear-felled site after a fuel adapted logging operation. In this study the losses at the clear-felled area is examined by studying the distribution of the remaining logging residues under and between the harvester heaps as well amount of logging residues that are left at the roadside landing after comminution. The results show that most of the reaming logging residues are well distributed at the clear-felled area between the harvester heaps. Additional logging residues are left at the clear-felled area since the forwarder cannot gather all logging residues from under the harvester heaps. In addition to this a not insignificant amount of logging residues are left at the roadside landing.

  • 27.
    Nilsson, Bengt
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nilsson, Daniel
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Distributions and Losses of Logging Residues at Clear-Felled Areas during Extraction for Bioenergy: Comparing Dried- and Fresh-Stacked Method2015In: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 6, no 11, 4212-4227 p.Article in journal (Refereed)
    Abstract [en]

    It is well known that a large proportion of available logging residues intended for extraction will not reach the energy-conversion industry, because some are lost during transportation or left on the clear-felled area. However, there is little understanding of where logging residue losses occur in the supply chain. In this study, the distribution of logging residues for two methods (dried- and fresh-stacked method) to extract logging residues were studied in one clear-felled area. In addition, residue fractions were examined in a detailed comparison. Even though the fresh-stacked method left somewhat more logging residues at the clear-felled area, the differences are small between the methods. Approximately 30% of the total amount of logging residues was left behind between the harvester heaps, with an additional 10%-15% under these heaps and approximately 2%-3% beneath the windrows. The final product that was delivered to the energy-conversion industry was very similar, regardless of the extraction method used. The delivered chipped logging residues had moisture contents of 37% and 36% following fresh- and dried-stacked methods respectively, and in both cases the needle content in the processed logging residues was approximately 10%. However, the total amount of fine fractions (needles and fines) was slightly higher following dried-stacking.

  • 28.
    Nilsson, Daniel
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nilsson, Bengt
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nutrient removal after whole-tree harvesting with the traditional Swedish dried-stacked method for removal of logging residues2015In: Papers of the 23rd European Biomass Conference: Setting the course for a biobased economyExtracted from the Proceedings of the International Conference held in Viennna, Asutria1-4 June 2015 / [ed] Obernberger I, Baxter D, Grassi A, Helm P, ETA-Florence Renewable Energies , 2015, 9-13 p.Conference paper (Refereed)
    Abstract [en]

    Bioenergy from logging residues is an important contributor to Swedish energy supplies. Logging residues where long defined and regarded as the unmerchantable aboveground biomass left behind in the clear-felled area, consisting of branches, tops and small trees that are gathered after the round wood harvest, but logging residues are nowadays regarded as a third assortment next to timber and pulpwood with high economic value. However long-term experiments on removal of logging residues from Norway spruce (Picea abies (L.)Karst) stands have shown both growth reductions and growth increase in the next generation, because of decreasing amounts of nutrients. So an increased removal of logging residues requires some sort of compensation of nutrients. Therefore it is of importance to investigate how much nutrients that is removed from the stand after whole-tree harvesting.

    In this study the removal of the nutrients nitrogen (N), phosphorus (P), calcium (Ca), potassium (K) and magnesium (Mg) have been investigated by laboratory analysis of the nutrients together with the actual removal of stemwood, bark and logging residues. The study has also investigated the distribution of nutrients at the clear-felled area.

    The results show that approximately half of the total nutrient removed in whole tree harvesting is done with the removal of stemwood and bark. The results also show that approximately 30% of the total amount of nutrients is left at the clear-felled area.

  • 29.
    Persson, Helena
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Carlsson, Bo
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Perers, Bengt
    DTU.
    Development and validation of a TRNSYS/TRNSED-software for combi-heating systems2013In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257Article in journal (Refereed)
    Abstract [en]

    There is a need for accurate and readily available information about theoptimization, economics, and environmental impacts of combi-heating systems.Accordingly, the authors have developed TRNSYS-based software called Flexifuel thatincludes a TRNSED application for calculating the annual system performance ofcombi-heating systems involving any combination of heat pumps, flat or vacuumtube solar collectors, pellet burners, electric auxiliary heaters, and heatstorage tanks. Selection of less complex software systems and types reduces thesimulation time without significantly affecting the accuracy of the results.Annual performance data for a system can be simulated in from one to twominutes. Comparison of accumulated theoretical and measured performance dataover the time period for a full-scale test plant with heat pumps and solarcollectors showed that simulation errors were below 5%.

  • 30.
    Persson, Helena
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Perers, Bengt
    DTU.
    Carlsson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Type12 and Type56: a load structure comparison in TRNSYS2011Conference paper (Refereed)
  • 31.
    Poudel, Bishnu Chandra
    et al.
    Mid Sweden University.
    Sathre, Roger
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bergh, Johan
    SLU, Alnarp.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Lundström, Anders
    Hyvonen, Ritta
    Potential effects of intensive forestry on biomass production and total carbon balance in north-central Sweden2012In: Environmental Science and Policy, ISSN 1462-9011, E-ISSN 1873-6416, Vol. 15, no 1, 106-124 p.Article in journal (Refereed)
    Abstract [en]

    We quantify the potential effects of intensive forest management activities on forest production in north-central Sweden over the next 100 years, and calculate the potential climate change mitigation feedback effect due to the resulting increased carbon stock and increased use of forest products. We analyze and compare four different forest management scenarios (Reference, Environment, Production, and Maximum), all of which include the expected effects of climate change based on SRES B2 scenario. Forest management practices are intensified in Production scenario, and further intensified in Maximum scenario. Four different models, BIOMASS, HUGIN, Q-model, and Substitution model, were used to quantify net primary production, forest production and harvest potential, soil carbon, and biomass substitution of fossil fuels and non-wood materials, respectively. After integrating the models, our results show that intensive forestry may increase forest production by up to 26% and annual harvest by up to 19%, compared to the Reference scenario. The greatest single effect on the carbon balance is from using increased biomass production to substitute for fossil fuels and energy intensive materials. Carbon stocks in living tree biomass, forest soil and wood products also increase. In total, a net carbon emission reduction of up to 132 Tg (for Maximum scenario) is possible during the next 100 years due to intensive forest management in two Swedish counties, Jamtland and Vasternorrland

  • 32.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hermansson, Sven
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Characterization of the fuel bed combustion of wood residues in a 4 MW grate boiler2015In: European Biomass Conference and Exhibition Proceedings, 2015, 741-744 p.Conference paper (Refereed)
    Abstract [en]

    Information about distributions of temperature and gas species within the fuel bed is of great importance in studying the formation of pollutants in an industrial-scale biomass boiler. The main objective of this study was to investigate the gas composition and temperature in some available sections of the fuel bed of a 4 MW reciprocating grate boiler, burning mixture of fresh pine wood chips, bark, and sawdust with two significantly different moisture content levels. The averageCO, CO2,CH4, and O2 concentrations measured during the combustion of the more moist fuel (about 60 mass %) were about 12, 12, 2, and 4 vol. %, respectively, whereas the corresponding values for the less moist fuel (about 45 mass %) were about15, 10, 2.5, and 5 vol. %, respectively. Higher concentration of CO and lower concentration of CO2 for the less moist fuel could originate either from the char conversion process or from the reactions of the devolatilizationgas products.

  • 33.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    In-bed combustion charachteristics of wet wood chips and sawdust in a full-scale grate boiler2017In: Proceedings 13th International Conference on Energy for a Clean Environment, 2017Conference paper (Refereed)
  • 34.
    Rupar-Gadd, Katarina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Forss, Jörgen
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Self-heating properties of softwood samples investigated by using isothermal calorimetry2017In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909Article in journal (Refereed)
    Abstract [en]

    The investigation focused on obtaining experimental results from the self-heating properties of different softwood samples during lab-scale storage. The samples investigated were a mixture of dried soft wood sawdust, softwood pellets 8 mm in diameter, and aged softwood sawdust stored outdoors for three months. Isothermal calorimetry was used to measure the heat released from the biomass samples and assess the contribution to self-heating during storage. Softwood samples were stored at 20 °C, 50 °C, 55 °C and 60 °C, and the metals manganese, copper and iron were added as a water solution to investigate if the presence of metals would increase the risk of self-heating. For most sample series, the highest levels of heat release were found after approximately 10 days of storage; sample series stored at 50 °C displayed the highest levels. The addition of copper resulted in levels of heat release 135% higher than samples without metal added.

  • 35.
    Sathre, Roger
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Haus, Sylvia
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Time Dynamics and Radiative Forcing of Forest Bioenergy Systems2013In: Forest BioEnergy Production: Management, Carbon Sequestration and Adaptation, Springer, 2013, 185-206 p.Chapter in book (Refereed)
    Abstract [en]

    In this chapter we explore the temporal dynamics of using forest bioenergy to mitigate climate change. We consider such issues as: growth dynamics of forests under different management regimes; the substitution effects of different bioenergy and biomaterial uses; temporary carbon storage in harvested biomass; the availability of different biomass fractions at different points of a wood product life cycle; and changes in carbon content of forest soils. We introduce the metric of radiative forcing, which quantifies the accumulating energy due to the global greenhouse effect, and we describe a method to estimate quantitatively and to compare the cumulative radiative forcing (CRF) of forest bioenergy systems and reference fossil energy systems. In three case studies, we describe the time dynamics and estimate the CRF profiles of various forest biomass systems.

  • 36.
    Sathre, Roger
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Truong, Nguyen Le
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Climate effects of electricity production fuelled by coal, forest slash and municipal solid waste with and without carbon capture2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 122, 711-723 p.Article in journal (Refereed)
    Abstract [en]

    We analyse the climate implications of producing electricity in large-scale conversion plants using coal, forest slash and municipal solid waste with and without carbon capture and storage (CCS). We calculate the primary energy, carbon dioxide (CO2) and methane (CH4) emission profiles, and the cumulative radiative forcing (CRF) of different systems that produce the same amount of electricity. We find that using slash or waste for electricity production instead of coal somewhat increases the instantaneous CO2 emission from the power plant, but avoids significant subsequent emissions from decaying slash in forests or waste in landfills. For slash used instead of coal, we find robust near- and long-term reductions in total emissions and CRF. Climate effects of using waste instead of coal are more ambiguous: CRF is reduced when CCS is used, but without CCS there is little or no climate benefits of using waste directly for energy, assuming that landfill gas is recovered and used for electricity production. The application of CCS requires more fuel, but strongly reduces the CO2 emissions. The use of slash or waste together with CCS results in negative net emissions and CRF, i.e. global cooling.

  • 37.
    Truong, Nguyen Le
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Costs and primary energy use of energy supply options to buildings of different energy efficiency levels2016In: 2016 ACEEE Summer Study on Energy Efficiency in Buildings: From Components to Systems, From Buildings to Communities, American Council for an Energy Efficient Economy, 2016Conference paper (Refereed)
    Abstract [en]

    An appropriate energy solution for buildings depends on the scale of demand and the availability of the surrounding technical infrastructure. Building energy demand can be altered by the application of various energy efficiency measures whereas the performance of the energy supply system can be changed by the involvement of various technologies. As a result, optimal energy supply options could depend on various parameters that depend on specific contexts. In this study, different options to supply energy to apartment buildings of different energy efficiency levels in Sweden are investigated. Different renewable-based alternatives to produce heat and electricity based on various state-of-the-art technologies are considered. The optimizations are based on the hourly variation throughout the year of energy demand and of different energy supply systems that change with the ambient conditions such as temperature and solar radiation. The results prove that optimal options for a building depend on its scale of energy demand and on the availability of technologies in the market. Also, there is a tradeoff between monetary costs and primary energy use in supplying energy to apartment buildings. This study shows that it is essential to consider the interaction between energy demand and supply to estimate the costs and primary energy use for energy supply alternatives. A heating system with an electric heat pump shows to be primary energy efficient option whereas that with a wood pellet boiler is a more cost efficient once. However, an energy supply option based on a combined heat and power unit using fuel cell technology could potentially be the most cost- and primary energy efficient option for buildings with low energy demand.

  • 38.
    Truong, Nguyen Le
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Costs of CO2 Emission Reduction in Biomass-Based District Heat Production Systems2014In: 22nd European Biomass Conference and Exhibition - EUBC&E2014, Hamburg, Germany, June 23-26, 2014, ETA-Florence Renewable Energies , 2014, 1401-1406 p.Conference paper (Other academic)
    Abstract [en]

    Efficient biomass-based district heat production systems (DHS) can contribute to achieving the social targets of environmental and energy security for countries with demand for space and water heating. In this study, we evaluate the costs of CO2 emission reduction from biomass-based district heating systems in comparison with fossil-based ones under different scales of district heat production, and we relate this cost to estimated damage costs of CO2 emission. Our calculations are based on a real heat load duration curve for a city in southern Sweden. The value of cogenerated electricity is assumed to be equal to that produced in minimum-cost standalone condensing power plants. The difference of the production cost and CO2 emission between fossil- and biomass-based systems is used to calculate the cost of CO2 emission reduction. We consider four different sizes of DHSs, from 50 to 300 GWhheat per year, to investigate how the CO2 emission reduction costs varies with the scale of DHS. We found that the district heat production cost for a minimum-cost DHS depends on scales of district heating systems and that the cost effectiveness between biomass- and fossil-based systems varies for different scales. The costs of CO2 emission reduction vary from €7.7 to €9.4 per ton of CO2e depending on the size of DHS. This cost is generally lower than estimated damage costs of CO2 emission.

  • 39.
    Truong, Nguyen Le
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Minimum-cost district heat production systems of different sizes under different environmental and social cost scenarios2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, 881-893 p.Article in journal (Refereed)
    Abstract [en]

    District heat systems can contribute to the achievement of social and environmental targets and energy security. District heat production systems (DHSs) vary in size depending on heat demand, which is influenced by several factors such as local climatic conditions and the sizes of the communities they serve. In this study, we analyzed options for minimum-cost DHSs of different sizes under different environmental and social cost scenarios. We calculated the production cost and primary energy use of district heat for minimum-cost options by considering a value of cogenerated electricity equivalent to the value of electricity produced in minimum-cost standalone condensing power plants. We varied the size of DHSs from 100 to 1800 GWhheat per year to investigate how size influences the minimum-cost compositions of production units and district heat production costs. We determined that the optimal composition and cost of district heat production is dependent on the size of the system, the overall load factor of heat demand and the technologies considered for both DHSs and reference power plants. In general, cogenerated district heat is more energy-efficient than district heat from heat-only production and also more cost-efficient, except for small DHSs, for which cogenerated district heat is more costly than heat-only production. The cost and primary energy use of district heat production is dependent on environmental and social cost scenarios; however, this dependence is reduced if a DHS is cost-minimized and based on cogenerated units.

  • 40.
    Truong, Nguyen Le
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Solar heating systems in renewable-based district heating systems2014In: Energy Procedia, ISSN 1876-6102, Vol. 61, no 1460, 1463Article in journal (Refereed)
    Abstract [en]

    In this study, we explored cost-optimal renewable-based district heat production systems and potential to integrate solar heating in such systems under different contexts. We investigated under which conditions a solar heating system become cost-efficient to integrate in district heat production systems and the consequences of this integration. We considered a small-scale district heat production system in the south of Sweden where district-heat production cost is higher and hence it is more cost efficient to integrate solar heating in such district heat production systems. The cost-efficiency of integrating solar heating in a minimum-cost renewable-based district heat production system depends on future fuel prices and investment costs of solar heating systems. In any case, integrating solar heating will help to reduce the use of other primary energy resources as biomass.

  • 41.
    Truong, Nguyen Le
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Heat supply of multi-apartment buildings with varied heat demands2014In: Energy Procedia, ISSN 1876-6102, Vol. 61, 1464-1467 p.Article in journal (Refereed)
    Abstract [en]

    In multi-apartment buildings, changes in energy demand may influence cost-optimal heat supply options. District heat based on combined heat and power production has proved to be cost- and primary energy-efficient option for heating purposes in the residential sector. However, for customers with a low heat demand, local heat supply options may be more cost-efficient than district heat supply options. In this study, we investigated cost-optimal options to supply heat to a multi-apartment building in Växjö city, Sweden. We considered biomass-based alternatives for district heating and local heating based on wood pellet boiler and ground-source electric heat pump, also combined with solar heating systems. Furthermore, we evaluated how a varied yearly heat demand influences the cost and primary energy efficiency of the different heat technologies. We found that both fuel costs and initial investment costs of heating systems play an important role for the cost efficiency of the different heat supply options. District heat is not always cost efficient for multi-apartment buildings especially for low energy buildings with minimum heat demand. There is also a tradeoff between heating cost and primary energy use in supplying heat to multi-apartment buildings.

  • 42.
    Vadman, Patric
    et al.
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Burén, Peter
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Utvecklingspotential i gamla vattenkraftsstationer: Fallstudie av Långgölsmåla vattenkraftsstation2015Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
  • 43.
    Valtersson, Johanna
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Värmeförluster från kulvertar2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I den har rapporten kartläggs och bedöms omfattningen av värmeförluster från kulvertar i Landstinget Kronobergs sekundära fjärrvärmenät på Sigfridsområdet. Teoretiska stationära värmeförlustberäkningar har utförts med Petter Wallenténs samband från 1991 samt med det via internet tillgängliga beräkningsprogrammet Logstor Calculator 2.1.

    Beräkningar över energibesparingen vid ett byte av de äldsta kulvertarna i det sekundära nätet till nya kulvertar visar att tvillingkulvertar i isolerklass 2 är att föredra framför enkelrör både i isolerklass 2 såväl som 3.

    Rapporten behandlar miljöaspekter kring fjärrvärme samt möjligheter och konsekvenser kring en energieffektivisering av distributionen genom sänkta systemtemperaturer.

  • 44.
    Westeneng, Teus
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Tajadura Cubillo, Adrian
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    De Miguel, Rodrigo
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Conceptual design of a piston and piston rod for a new wave energy converter concept2017Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
1 - 44 of 44
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