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  • 1.
    Abbas, Ghazanfar
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Ashfaq, M.
    Chaudhry, M. Ashraf
    Khan, Ajmal
    Ahmad, Imran
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Electrochemical study of nanostructured electrode for low-temperature solid oxide fuel cell (LTSOFC)2014Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 38, nr 4, s. 518-523Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zn-based nanostructured Ba0.05Cu0.25Fe0.10Zn0.60O (BCFZ) oxide electrode material was synthesized by solid-state reaction for low-temperature solid oxide fuel cell. The cell was fabricated by sandwiching NK-CDC electrolyte between BCFZ electrodes by dry press technique, and its performance was assessed. The maximum power density of 741.87 mW-cm(-2) was achieved at 550 degrees C. The crystal structure and morphology were characterized by X-ray diffractometer (XRD) and SEM. The particle size was calculated to be 25 nm applying Scherer's formula from XRD data. Electronic conductivities were measured with the four-probe DC method under hydrogen and air atmosphere. AC Electrochemical Impedance Spectroscopy of the BCFZ oxide electrode was also measured in hydrogen atmosphere at 450 degrees C.

  • 2.
    Arjmand, Mehdi
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Liu, Longcheng
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Neretnieks, Ivars
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk apparatteknik.
    Exergetic efficiency of high-temperature-lift chemical heat pump (CHP) based on CaO/CO2 and CaO/H2O working pairs2013Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 37, nr 9, s. 1122-1131Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of reversible chemical reactions in recuperation of heat has gained significant interest due to higher magnitude of reaction heat compared to that of the latent or sensible heat. To implement chemical reactions for upgrading heat, a chemical heat pump (CHP) may be used. A CHP uses a reversible chemical reaction where the forward and the reverse reactions take place at two different temperatures, thus allowing heat to be upgraded or degraded depending on the mode of operation. In this work, an exergetic efficiency model for a CHP operating in the temperature-level amplification mode has been developed. The first law and the exergetic efficiencies are compared for two working pairs, namely, CaO/CO2 and CaO/H2O for high-temperature high-lift CHPs. The exergetic efficiency increases for both working pairs with increase in task, TH, decrease in heat source, TM, and increase in condenser, TL, temperatures. It is also observed that the difference in reaction enthalpies and specific heats of the involving reactants affects the extent of increase or decrease in the exergetic efficiency of the CHP operating for temperature-level amplification.

  • 3.
    Carlson, Annelie
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem. Linköpings universitet, Tekniska högskolan.
    On cost-effective technical measures to avoid environmental damage of regional energy systems2002Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 26, nr 12, s. 1103-1115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The production of heat and electricity can cause large environmental impacts and, hence, large costs for society. Those are costs that are seldom taken into consideration. An important question is how the future technical energy systems should be formed if environmental costs were considered as any other good or service, such as raw material, capital and labour. This study comprises cost-effective technical measures when monetary values of external effects are included in an energy system analysis. It is an analysis of how the present energy system can for society be cost-effectively reconstructed to be more sustainable. A regional energy system model has been developed to perform the study and it concentrates upon production of heat in single-family houses, multi-dwelling buildings, non-residential promises and district heating systems. The analysis adopts a business economic perspective, using present prices of energy carriers, and a more socio-economic perspective, in which external costs are included. The result of the analysis is the optimal mix of energy carriers as well as new and existing heating plants that minimizes the costs of satisfying a demand for heat. The results show that it is profitable to invest in new heating plants fuelled with woody biomass. Furthermore, the external costs arising with satisfying the demand for heat can decrease substantially, 60%, by carrying through with the investments that are cost-effective according to the institutional rules valid today. When monetary values of external costs are taken into consideration, this number is additional 5-percentage points lower. It is shown that if environmental costs are included it is more expensive to continue with business as usual than it is to reconstruct and run a more sustainable energy system.

  • 4.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Alternative Pathways to a Fossil-Fuel Free Energy System in the Mälardalen region of Sweden2007Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 31, nr 12, s. 1226-1236Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a study on alternative pathways to a fossil-fuel free regional energy system in the Mälardalen region of Sweden with a population of 3 million inhabitants. We describe and address how the region can be made independent of fossil fuels by integration of resource management, technology advances, and behaviour change in energy use. First we investigate the consumption pattern of the inhabitants. Then we study what resources are available, and how these can be used to fulfil the different demands. If we just use the resources in a pattern of business as usual today without changing the behaviour, the balance between demands and resources is difficult to reach. By combining a slightly different behaviour and a change of crops we can fulfil the needs and it might even be possible to have a surplus of resources. Some advanced technological solutions have also been proposed. For example, dedicated biomass energy plants such as Salix, straw, hemp and some cereals can be used for ethanol production and the residues can be gasified to produce dimethylether (DME), which is good as a replacement for diesel fuel. Still the fueldemand for transport is high, and the vehicle weight could be further reduced. For example, by going back to the car size we had only 10 years ago the weight would be 25-30% less, and fuelconsumption would be at least 15% lower. With diesel engines instead of Otto engines the fuel consumption could be reduced by 35%, and with hybrid technology additional 20% fuel reduction could be gained. Improved public transportation will also give a positive effect especially for those commuting between the larger cities and between the cities and the suburbs. The results of our calculations show that it would be possible to accomplish a fossil-free energy system in the Mälardalen region. The results of this study are important since it shows that an energy balance without fossil fuels could be possible for an area with a population in the order of 3 million people, which would also be valuable in studies of other areas in the world.

  • 5.
    Danielsson, Oskar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära och åskforskning.
    Eriksson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära och åskforskning.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära och åskforskning.
    Study of a Longitudinal Flux Permanent Magnet Linear Generator for Wave Energy Converters2006Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 30, nr 14, s. 1130-1145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A directly coupled linear permanent magnet generator of longitudinal flux-type is investigated. The generator will be used for power take-off in a wave energy converter. A combined field- and circuit model, solved by a time stepping finite element technique, is used to model and analyse the electromagnetic behaviour of the machine. A large number of simulations form the basis of a design study where the influence of armature current level, number of cables per slot, and pole width is investigated with respect to efficiency, generator size, and the load angle. A case study is performed for a chosen generator design. The electromagnetic behaviour is examined both for nominal load and for overloads. The generator has a nominal output power of 10 kW for a constant piston speed of 0.7 m s(-1). The electromagnetic efficiency at nominal load is 86.0%, the load angle 6.6 degrees, and the power fluctuation 1.3%. At 300% overload the load angle barely exceeds 12 degrees and the cable temperature is below 25 degrees C provided that the stator back is thermally connected to the sea water. The numerical calculations have been verified for small speeds by experiments.

  • 6.
    Eriksson, Lina
    et al.
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Energi och cirkulär ekonomi.
    Morandin, Matteo
    Chalmers University of Technology, Sweden.
    Harvey, Simon
    Chalmers University of Technology, Sweden.
    A feasibility study of improved heat recovery and excess heat export at a Swedish chemical complex site2018Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 42, nr 4, s. 1580-1593Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New ambitious targets for reduced greenhouse gas emissions and increased energy efficiency in industry and in the stationary energy sector provide incentives for industrial plants to investigate opportunities for substantially increasing recovery and use of excess heat from their operations. This work investigates the economic feasibility of recovering industrial excess heat at a Swedish chemical complex site for increased site internal heat recovery or export to a regional district heating (DH) network. The work is based on investment cost data estimated in previous work by the authors. A site-wide heat collection and distribution system based on circulating hot water was envisioned, which is also connected to a regional DH network. With the help of multiobjective optimization, the optimal heat contributions from the individual plant sites were identified that minimize the total system cost for a large range of options involving different quantities of internally recovered heat and heat export to the DH system. A payback period analysis was conducted together with a risk assessment to take into account uncertainty regarding utility steam production cost and heat sale price. The results of the study indicate that a payback period of around 3 years can be achieved for a number of cases in which 30% to 50% of the total excess heat produced by the site plants is recovered. Although it seems more profitable to recover heat at the site rather than exporting heat to the DH system only, profitability appears to be maximized by hybrid solutions that allow a share of the excess heat to be sold to the DH system and some heat to be recovered at the site simultaneously.

  • 7. Fan, L.
    et al.
    He, C.
    Zhu, Binzhu
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi. Hubei University Wuhan, China.
    Role of carbonate phase in ceria-carbonate composite for low temperature solid oxide fuel cells: A review2016Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ceria-salt composites represent one type of promising electrolyte candidates for low temperature solid oxide fuel cells (LT-SOFCs), in which ceria-carbonate attracts particular attention because of its impressive ionic conductivity and unique hybrid ionic conduction behavior compared with the commonly used single-phase electrolyte materials. It has been demonstrated that the introduction of carbonate in these new ceria-based composite materials initiates multi new functionalities over single-phase oxide, which therefore needs a comprehensive understanding and review focus. In this review, the roles of carbonate in the ceria-carbonate composites and composite electrolyte-based LT-SOFCs are analyzed from the aspects of sintering aid, electrolyte densification reagent, electrolyte/electrode interfacial 'glue' and sources of super oxygen ionic and proton conduction, as well as the oxygen reduction reaction promoter for the first time. This summary remarks the significance of carbonate in the ceria-carbonate composites for low temperature, 300-600°C, SOFCs and related highly efficient energy conversion applications.

  • 8.
    Fiedler, Frank
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Miljöteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Miljöteknik.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Miljöteknik.
    Nordlander, Svante
    Comparison of carbon monoxide emissions and electricity consumption of modulating and non-modulating pellet and solar heating systems2007Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 31, nr 10, s. 915-930Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Emission and electricity consumption are important aspects of a pellet heating system. Low noxious emissions, particularly carbon monoxide, are a measure of a well-performing system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner, poor adjustment of the combustion air and insufficient maintenance. The carbon monoxide output, the thermal performance and the electricity consumption for modulating and non-modulating operation mode have been investigated by simulations of four stoves/boilers as part of combined solar and pellet heating systems. The systems have been modelled with the simulation programme TRNSYS and simulated with the boundary conditions for space heating demand, hot water load and climate data as used in earlier research projects. The results from the simulations show that operating the pellet units with modulating combustion power reduces the number of starts and stops but does not necessarily reduce the carbon monoxide output. Whether the carbon monoxide output can be reduced or not depends very strongly on the reduction of starts and stops and how much the carbon monoxide emissions increase with decreased combustion power, which are in turn dependent on the particular settings of each pellet burner and how the heat is transferred to the building. However, for most systems the modulating operation mode has a positive impact on carbon monoxide emissions. Considering the total auxiliary energy demand, including the electricity demand of the pellet units, the modulating combustion control is advantageous for systems 1 and 4 for the used boundary conditions. The study also shows that an appropriate sizing of the stove or boiler has a huge potential for energy saving and carbon monoxide emission reduction.

  • 9.
    Gao, Zhan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Mao, Zongqiang
    Wang, Cheng
    Huang, Jianbing
    Liu, Zhixiang
    Composite electrolyte based on nanostructured Ce0.8Sm0.2O1.9 (SDC) for low-temperature solid oxide fuel cells2009Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 33, nr 13, s. 1138-1144Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanostructured Ce0.8Sm0.2O1.9 (SDC) is investigated for low-temperature solid oxide fuel cells based on SDC- 30 wt% (53 mol% Li2CO3:47 mol % Na2CO3) composite electrolyte in this work. SDC is prepared by the combined citrate and EDTA complexing method. X-ray powder diffraction shows that it forms a well-cubic fluorite structure after being sintered at 700 degrees C for 2 h. The particle is about 12 nm detected by the transmission electron microscopy. Conductivity for the composite is much higher than the pure SDC at comparable temperatures. A transition of ionic conductivity occurs at 450 degrees C for the composite electrolyte. The single cells are fabricated by a simple dry-pressing process and tested at 450-600 degrees C. A maximum power density of 900 mW cm(-2) and the open-circuit voltage of 0.92 V are achieved at 600 degrees C. The conduction mechanism has been discussed by comparing the conductivity of composite electrolyte under different conditions. AC impedance for single cell indicates that the electrochemical process involving cathode and anode reactions is the rate-limiting step.

  • 10. Gao, Zhan
    et al.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Fransson, Torsten
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Development of Direct Methanol Low Temperature Fuel Cells from a Polygeneration, Perspective2011Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 35, s. 690-696Artikel i tidskrift (Refereegranskat)
  • 11.
    Gao, Zhan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Mao, Zongqiang
    Development of methanol-fueled low-temperature solid oxide fuel cells2011Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 35, nr 8, s. 690-696Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low-temperature solid oxide fuel cell (SOFC, 300-600 degrees C) technology fueled by methanol possessing significant importance and application in polygenerations has been developed. Thermodynamic analysis of methanol gas-phase compositions and carbon formation indicates that direct operation on methanol between 450 and 600 degrees C may result in significant carbon deposition. A water steam/methanol ratio of 1/1 can completely suppress carbon formation in the same time enrich H(2) production composition. Fuel cells were fabricated using ceria-carbonate composite electrolytes and examined at 450-600 degrees C. The maximum power density of 603 and 431 mW cm(-2) was achieved at 600 and 500 degrees C, respectively, using water steam/methanol with the ratio of 1/1 and ambient air as fuel and oxidant. These results provide great potential for development of the direct methanol low-temperature SOFC for polygenerations.

  • 12.
    Gebremedhin, Alemayehu
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem.
    Moshfegh, Bahram
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem.
    Modelling and optimization of district heating and industrial energy system - An approach to a locally deregulated heat market2004Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 28, nr 5, s. 411-422Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Regions with densely concentration of industries and district heating systems (DHS) could be interesting study object from the light of an integrated heat market on local basis. System analysis with a widened system boundary could be used as an approach to evaluate the benefit of an integrated heat supply system. In this study, an energy system model consisting of totally seven different participants is designed and the optimization results of the system analysis are presented. With applied data and assumptions, the study shows that a significant amount of the heat demand within two sub-systems can be covered by heat supply from the heat market (the entire heat comes from two industries). Shadow prices, which can be used for heat pricing, indicate the advantage of an integrated system. The system cost reduction through integration and the availability of several actors with diverse energy supply system, makes the region under study an interesting area to prove a locally deregulated heat market.

  • 13.
    Gong, Mei
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem. Linköpings universitet, Tekniska högskolan.
    Exergy analysis of a pulp and paper mill2005Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 29, nr 1, s. 79-93Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different energy and exergy concepts and methods are presented and applied to a Swedish pulp and paper mill. Flow diagrams show that the exergy content is mostly much less than the energy content of the flows. The largest exergy losses appear in the boilers. Heating processes are highly exergy inefficient. A limited Life Cycle Exergy Analysis (LCEA) shows that the exergy output amounts to over 3 times the spent exergy as non-sustainable resources. By replacing the present use of non-sustainable resources, mostly fuel oil, the mill could move towards a truly sustainable process.

  • 14.
    Gong, Mei
    Division of Energy Systems, Department of Mechanical Engineering, Linköping University, Linköping, Sweden.
    Exergy analysis of a pulp and paper mill2005Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 29, nr 1, s. 79-93Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different energy and exergy concepts and methods are presented and applied to a Swedish pulp and paper mill. Flow diagrams show that the exergy content is mostly much less than the energy content of the flows. The largest exergy losses appear in the boilers. Heating processes are highly exergy inefficient. A limited Life Cycle Exergy Analysis (LCEA) shows that the exergy output amounts to over 3 times the spent exergy as non-sustainable resources. By replacing the present use of non-sustainable resources, mostly fuel oil, the mill could move towards a truly sustainable process. Copyright © 2005 John Wiley & Sons, Ltd.

  • 15.
    Gronkvist, Stefan
    et al.
    Royal Institute of Technology, Department of Chemical Engineering and Technology, Division of Energy Processes, Stockholm, Sweden.
    Sjödin, Jörgen
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Westermark, M.
    Royal Institute of Technology, Department of Chemical Engineering and Technology, Division of Energy Processes, Stockholm, Sweden.
    Models for assessing net CO2 emissions applied on district heating technologies2003Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 27, nr 6, s. 601-613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Methodologies to assess the effects of energy projects on global carbon dioxide emissions will be an important feature of a future international carbon dioxide trading system. In this paper, we present and discuss four different models for assessing the net carbon dioxide emissions resulting from a certain energy project. These models are applied to different district heating technologies. To judge the mitigation performance of a project, the amount of carbon dioxide released in kilograms is expressed per megawatt-hour of useful district heating produced. All the models consider the marginal change caused by the project on the electric power system. The different model perspectives are discussed, and it is shown that the choice of model is very critical for assessing the net carbon dioxide emissions from an energy project.

  • 16.
    Grönkvist, Stefan
    et al.
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Sjödin, Jörgen
    Linköping Institute of Technology, Department of Mechanical Engineering, Division of Energy Systems.
    Westermark, Mats
    KTH, Tidigare Institutioner                               , Kemiteknik.
    Models for assessing net CO2 emissions applied on district heating technologies2003Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 27, nr 6, s. 601-613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Methodologies to assess the effects of energy projects on global carbon dioxide emissions will be an important feature of a future international carbon dioxide trading system. In this paper, we present and discuss four different models for assessing the net carbon dioxide emissions resulting from a certain energy project. These models are applied to different district heating technologies. To judge the mitigation performance of a project, the amount of carbon dioxide released in kilograms is expressed per megawatt-hour of useful district heating produced. All the models consider the marginal change caused by the project on the electric power system. The different model perspectives are discussed, and it is shown that the choice of model is very critical for assessing the net carbon dioxide emissions from an energy project.

  • 17.
    Gunasekara, Samman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Ignatowicz, Monika
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Chiu, Justin NingWei
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Thermal conductivity measurement of erythritol, xylitol, and their blends for phase change material design: A methodological study2019Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 43, nr 5, s. 1785-1801Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work presents and discusses a detailed thermal conductivity assessment of erythritol, xylitol, and their blends: 25 mol% erythritol and 80 mol% erythritol using the transient plane source (TPS) method with a Hot Disk Thermal Constants Analyzer TPS‐2500S. Thereby, the thermal conductivities of xylitol, 25 mol% erythritol, 80 mol% erythritol, and erythritol were here found for respectively in the solid state to be 0.373, 0.394, 0.535, and 0.589 W m−1 K−1 and in the liquid state to be 0.433, 0.402, 0.363, and 0.321 W m−1 K−1. These obtained results are comprehensively and critically analyzed as compared to available literature data on the same materials, in the phase change materials (PCMs) design context. This study clearly indicates that these thermal conductivity data in literature have considerable discrepancies between the literature sources and as compared to the data obtained in the present investigation. Primary reasons for these disparities are identified here as the lack of sufficiently transparent and repeatable data and procedure reporting, and relevant standards in this context. To exemplify the significance of such transparent and repeatable data reporting in thermal conductivity evaluations in the PCM design context, here focused on the TPS method, a comprehensive measurement validation is discussed along various residual plots obtained for varying input parameters (ie, the heating power and time). Clearly, the variations in the input parameters give rise to various thermal conductivity results, where choosing the most coherent result requires a sequence of efforts per material, because there are no universally valid conditions. Transparent and repeatable data and procedure reporting are the key to achieve comparable thermal conductivity results, which are essential for the correct design of thermal energy storage systems using PCMs.

  • 18.
    Gustafsson, Stig-Inge
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Are Earth Tube Heat Exchangers of Interest when Heating Buildings?1993Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 17, nr 7, s. 597-604Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is a well-known fact that the temperature of the soil, some metres below the surface, is relatively stable. If this heat could be utilized by use of an earth tube heat exchanger, significant benefits could occur when space heating for buildings is considered. The inlet ventilation air is then led through a long earth tube in which it will, depending on their relative temperatures, take up heat from, or leave heat to, the surrounding soil. In this paper two case studies are presented. The buildings of concern are sited in the vicinity of Linköping, about 200 km south of Stockholm, Sweden. One of the cases utilizes heat from the earth tube in an air-to-water heat pump, while the other uses an air-to-air heat exchanger. The studies show that the earth tubes only to a very low degree contribute to the need of added heat in order to achieve a desirable indoor climate. Hence, the extra cost for the tube will not be balanced by the decreased cost for space heating. This discouraging result may have depended on heat pipes that were too short or the fact that the difference in temperature between the passing air stream and the surrounding soil was too small.

  • 19.
    Gustafsson, Stig-Inge
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem. Linköpings universitet, Tekniska högskolan.
    Load management in municipal electricity systems1997Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 21, nr 9, s. 787-791Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Load management is one means of reducing maximum electricity load, and hence also the cost of electricity. In Sweden, the amount charged during the maximum load hour might be about 200 times higher than the standard charge for one kilowatt-hour. If the load could be reduced by certain equipment in factories and buildings, the need for new power stations and higher capacity in the grid would also be decreased. Using electricity load data for one full year and a short computer program, this paper shows by how much the load could be reduced by postponing demand. If part of the load could be postponed by only one hour, this part may need to be only very small for maximum benefit. If longer time segments were practicable, larger chunks could be transferred. The main result of the study is, however, that load management in practice is a very subtle task if an optimal solution is to be achieved

  • 20.
    Gustafsson, Stig-Inge
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem. Linköpings universitet, Tekniska högskolan.
    Load management measures in a carpentry factory1998Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 22, nr 14, s. 1267-1274Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The wood manufacturing industry in Sweden is not very often the subject of academic research activities. In certain parts of Sweden, generally in rural areas, this industrial branch is of major importance as a local employer. If the companies could grow and prosper it would lead to a more vivid countryside and decrease migration to larger towns and cities. The council of the European Community has therefore introduced certain funds for research projects in such rural areas. This paper describes the use of electricity and heat in a carpentry factory. The result shows that energy conservation measures and load management might be of significant importance in order to make the company more profitable. Even small savings can be the difference between survival or bankruptcy. For the studied factory it is obvious that much equipment for heating purposes are in a poor state. The steam system which could be useful for decreasing the use of electricity heating suffers from leaking steam traps and other imperfections which lead to severe losses in both kilowatt-hours and money. The steam system is therefore not used in an optimal way

  • 21.
    Gustafsson, Stig-Inge
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Optimal use of solar collectors for residential buildings2001Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 25, nr 11, s. 993-1004Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solar radiation is an abundant free resource which may be used in the form of solar heated water. This is achieved in solar collectors which, unfortunately, are expensive devices and, further, the warm water must be stored in accumulators-items which also cost money. This paper shows how we have optimized the situation for a block-of-flats in Sweden. In order to find this point we have used the minimum life-cycle cost (LCC) concept as a criterion. The best solution is therefore found when that cost finds its lowest value. It is also examined under which conditions solar collectors are part of the optimal solution and further it is calculated what happens if this optimal point is abandoned, i.e. how much will the LCC increase if other than optimal solutions are chosen. LCC optimization for multi-family buildings almost always results in a heating system with low operating costs such as district heating or dual-fuel systems where a heat pump takes care of the base load and an oil boiler the peak. The installation cost must, however, be kept to a reasonable level. Expensive solar panel systems are therefore normally avoided if the lowest LCC shall be reached, at least for Swedish conditions. This is so even if the solar system has a very low operating cost. For buildings where the only alternative energy source is electricity, solar collectors seem to be on the rim of profitability, i.e. for an energy price of about 0.6 SEK kWh-1. Copyright © 2001 John Wiley and Sons, Ltd.

  • 22.
    Gustafsson, Stig-Inge
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Optimization of drying kiln operation2000Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 24, nr 1, s. 19-26Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When timber is to be used in the form of furniture it must be dried. Green timber contains many times more water than wood and if it is placed indoors the water will slowly evaporate. When the fibre saturation point is reached the wooden parts start to shrink and the shape of the details will change. If the wood is dried before it is used for furniture parts this calamity is reduced because shrinking has occurred already in the drying kiln when the raw material was in the form of lumber. This drying process uses a lot of heat which is produced by electricity or by firing wood chips or oil in boilers. The cost for these energy sources varies during the season or, for electricity, also during the day. This paper describes how to optimize the use of energy in two drying kilns located at a small carpentry factory in the south of Sweden. Monitored values from the factory are used in order to describe the process in close detail. These values are then used as a basis for a mathematical model which is designed in the form of a mixed integer linear program. The method makes it possible to optimize the operating schemes for the two dryers. Copyright (C) 2000 John Wiley & Sons, Ltd.

  • 23.
    Gustafsson, Stig-Inge
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Karlsson, Björn G
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Why is Life-Cycle Costing Important when Retrofitting Buildings1988Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 12, nr 2, s. 233-242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using life-cycle costing (LCC) gives us a means to find the best retrofit strategy for an apartment block. This method also shows us how important it is to consider the whole existing building as an energy system. If the best heating system is put into the house almost every shield retrofit is unprofitable. Having heating systems, with high variable costs combined with exhaust ventilation air pumps, sometimes makes it unprofitable to caulk the windows and doors.

    This article also shows the importance of using the accurate prices for the energy. Short-range marginal costs (SMRC) gives different retrofit strategies than normal tariffs used today. This also means that the retrofits do not correspond to the optimal use of the total national energy system and already scarce resources are used unnecessarily.

  • 24.
    Gustafsson, Stig-Inge
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Rönnqvist, Mikael
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Matematiska institutionen, Optimeringslära.
    Claesson, M
    Optimization models and solution methods for load management2004Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 28, nr 4, s. 299-317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electricity market in Sweden has changed during recent years. Electricity for industrial use can now be purchased from a number of competing electricity suppliers. Hence, the price for each kilowatt-hour is significantly lower than it was just two years ago and interest in electricity conservation measures has declined. However, part of the electricity tariff, i.e. the demand cost expressed in Swedish Kronor (SEK) for each kilowatt, is almost the same as before. Attention has thereby been drawn to load management measures in order to reduce this specific cost. Saving one kWh might lead to a monetary saving of between SEK 0.22 and SEK 914, this paper demonstrates how to eliminate only those kWh that actually save a significant amount of money. A load management system has been installed in a small carpentry factory that can turn off equipment based on a pre-set priority and number of minutes each hour. The question now is what level of the electricity load is optimal in a strictly mathematical sense, i.e. how many kW should be set in the load management computer in order to maximise profitability? In this paper, we develop a mathematical model that can be used as a tool both to find the most profitable subscription level and to control the choices to be made. Numerical results from a case study are presented. Copyright (C) 2004 John Wiley Sons, Ltd.

  • 25.
    Han, Song
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Techno-economic analysis of an integrated biorefinery system for poly-generation of power, heat, pellets and bioethanol2014Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 38, nr 5, s. 551-563Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bioethanol is an alternative to fossil fuels in the transportation sector. The use of pellet for heating is also an efficient way to mitigate greenhouse gas emissions. This paper evaluates the techno-economic performance of a biorefinery system in which an existing combined heat and power (CHP) plant is integrated with the production of bioethanol and pellet using straw as feedstock. A two-stage acid hydrolysis process is used for bioethanol production, and two different drying technologies are applied to dry hydrolysis solid residues. A sensitivity analysis is performed on critical parameters such as the bioethanol selling price and feedstock price. The bioethanol production cost is also calculated for two cases with either 10 year or 15 year payback times. The results show that the second case is currently a more feasible economic configuration and reduces production costs by 36.4%-77.3% compared to other types of poly-generation plants that are not integrated into existing CHP plants. 

  • 26.
    Höök, Mikael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Globala energisystem.
    Aleklett, Kjell
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Globala energisystem.
    A review on coal to liquid fuels and its coal consumption2010Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 34, nr 10, s. 848-864Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Continued reliance on oil is unsustainable and this has resulted in interest in alternative fuels. Coal-to-Liquids (CTL) can supply liquid fuels and have been successfully used in several cases, particularly in South Africa. This article reviews CTL theory and technology. Understanding the fundamental aspects of coal liquefaction technologies are vital for planning and policy-making, as future CTL systems will be integrated in a much larger global energy and fuel utilization system.

    Conversion ratios for CTL are generally estimated to be between 1-2 barrels/ton coal. This puts a strict limitation on future CTL capacity imposed by future coal production volumes, regardless of other factors such as economics, emissions or environmental concern. Assuming that 10% of world coal production can be diverted to CTL, the contribution to liquid fuel supply will be limited to only a few Mb/d. This prevents CTL from becoming a viable mitigation plan for liquid fuel shortage on a global scale. However, it is still possible for individual nations to derive significant shares of their fuel supply from CTL, but those nations must also have access to equally significant coal production capacities. It is unrealistic to claim that CTL provides a feasible solution to liquid fuels shortages created by peak oil. For the most part, it can only be a minor contributor and must be combined with other strategies.

  • 27.
    Johannes, Schmidt
    et al.
    Doctoral School Sustainable Development, University of Natural Resources and Applied Life Sciences, Peter Jordan StraBe 82,.
    Leduc, Sylvain
    International Institute for Applied Systems Analysis, Schlossplatz 1, A-2361 Laxenburg, Austria.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Kindermann, Georg
    International Institute for Applied Systems Analysis, Schlossplatz 1, A-2361 Laxenburg, Austria.
    Schmid, Erwin
    Institute for Sustainable Economic Development, University of Natural Resources and Applied Life Sciences, FeistmantelstraBe 4,.
    Potential of biomass-fired combined heat and power plants considering the spatial distribution of biomass supply and heat demand2010Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 34, nr 11, s. 970-985Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Combined heat and power (CHP) plants fired by forest wood can significantly contribute to attaining the target of increasingthe share of renewable energy production. However, the spatial distribution of biomass supply and of heat demand limits thepotentials of CHP production. This article assesses CHP potentials using a mixed integer programming model that optimizeslocations of bioenergy plants. Investment costs of district heating infrastructure are modeled as a function of heat demanddensities, which can differ substantially. Gasification of biomass in a combined cycle process is assumed as productiontechnology. Some model parameters have a broad range according to a literature review. Monte-Carlo simulations havetherefore been performed to account for model parameter uncertainty in our analysis. The model is applied to assess CHPpotentials in Austria. Optimal locations of plants are clustered around big cities in the east of the country. At current powerprices, biomass-based CHP production allows producing around 3% of the total energy demand in Austria. Yet, the heatutilization decreases when CHP production increases due to limited heat demand that is suitable for district heating.Production potentials are most sensitive to biomass costs and power prices.

  • 28.
    Karlsson, Magnus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Söderström, Mats
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Sensitivity analysis of investments in the pulp and paper industry: on investments in the chemical recovery cycle at a board mill2002Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 26, nr 14, s. 1253-1267Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the pulp and paper industry, energy costs represents a relatively large proportion of the value of production. When investing in new equipment, considerations concerning boundary conditions, such as electricity and oil prices, are therefore of great importance. A vital requirement is the identification of other key parameters influencing production costs as well as possible interaction between these parameters. In this paper, a sensitivity analysis is accomplished by using an optimization model that minimizes the system cost combined with a systematic approach involving a statistical method.

    The paper analyses the possibilities of investing in a new chemical recovery cycle, including a new recovery boiler and evaporation plant, at a Swedish board mill. The study includes a survey of future changes, together with forecasts of boundary conditions, such as changes in the price of electricity and oil. Interactions between different parameters are also examined.

  • 29.
    Kharseh, Mohamad
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Nordell, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Sustainable heating and cooling systems for agriculture2011Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 35, nr 5, s. 415-422Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Space heating/cooling systems account for approximately 40% of the global energy consumption. Such systems contribute to global warming by emitting 4×1010 MWh of heat and 3×1010 tons of CO2. There is a general understanding that the way to reduce global warming is a more efficient use of energy and increased use of renewable energy in all fields of the society. Ground-coupled heating/cooling systems, which have proven to make huge contributions in reducing energy consumption in Europe and North America, is here applied for poultry industry in Syria, as an example for the Middle East. There are e.g. 13 000 chicken farms in Syria producing 172 000 tons of meat per year. This industry employs directly almost 150 000 people. The total investments in chicken farming are 130 BSP (2 B). The annual mean air temperature in Syria is 15-18°C with winter temperatures close to freezing during two months. The chickens need a temperature of 21-35°C, depending on age, and the heating of all Syrian chicken plants consume 173×103 tons of coal (1196 GWh). In the summer time, the ambient air temperature in Syria could reach above 45°C. The chicken farms have no cooling systems since conventional cooling system is too expensive. The elevated temperature inside the farms reduces the chicken growth and lots of chicken die of overheating. The ground temperature at 10 m depth is roughly equal to the annual mean air temperature. Using the ground as a heat source means a sustainable and less expensive heating of the chicken farms. During the summer, the ground is used as a source for free cooling, i.e. used directly for cooling of the plants without any cooling machines. Current study shows the design and simulated operation of a ground-coupled heating/cooling system for a typical chicken farm in Syria. Performed national potential study showed that the implementation of such ground coupled heating and cooling systems in the Syrian poultry sector would mean increased poultry production and considerable savings in money, energy, and the environment.

  • 30.
    Klugman, Sofia
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Karlsson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Modeling an industrial energy system: Perspectives on regional heat cooperation2008Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, nr 9, s. 793-807Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Through energy efficiency measures, it is possible to reduce heat surplus in the pulp and paper industry. Yet pulp and paper mills situated in countries with a heat demand for residential and commercial buildings for the major part of the year are potential heat suppliers. However, striving to utilize the heat within the mills for efficient energy use could conflict with the delivery of excess heat to a district heating system. As part of a project to optimize a regional energy system, a sulfate pulp mill situated in central Sweden is analyzed, focusing on providing heat and electricity to the mill and its surrounding energy systems. An energy system optimization method based on mixed integer linear programming is used for studying energy system measures on an aggregated level. An extended system, where the mill is integrated in a regional heat market (HM), is evaluated in parallel with the present system. The use of either hot sewage or a heat pump for heat deliveries is analyzed along with process integration measures. The benefits of adding a condensing unit to the back-pressure steam turbine are also investigated. The results show that the use of hot sewage or a heat pump for heat deliveries is beneficial only in combination with extended heat deliveries to an HM. Process integration measures are beneficial and even increase the benefit of selling more heat for district heating. Adding a condensing turbine unit is most beneficial in combination with extended heat deliveries and process integration.

  • 31.
    Klugman, Sofia
    et al.
    Högskolan i Gävle, Institutionen för teknik och byggd miljö, Ämnesavdelningen för energi- och maskinteknik.
    Karlsson, Magnus
    Department of Mechanical Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Moshfegh, Bahram
    Department of Mechanical Engineering, Division of Energy Systems, Linköping University, Linköping, Sweden.
    Modeling an industrial energy system: Perspectives on regional heat cooperation2008Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, nr 9, s. 793-807Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Through energy efficiency measures, it is possible to reduce heat surplus in the Pulp and paper industry. Yet pulp and paper mills situated in Countries with a heat demand for residential and commercial buildings for the major part of the year are potential heat Suppliers. However, striving to utilize the heat within the mills for efficient energy use Could conflict with the delivery of excess heat to a district heating system. As part of a project to optimize a regional energy system, a sulfate pulp mill situated in central Sweden is analyzed, focusing on providing heat and electricity to the mill and its surrounding energy systems. An energy system optimization method based on mixed integer linear programming is used for studying energy system measures on an aggregated level. An extended system, where the mill is integrated in a regional heat market (HM), is evaluated in parallel with the present system. The use of either hot sewage or a heat PUMP for heat deliveries is analyzed along with process integration measures. The benefits of adding a condensing unit to the back-pressure steam turbine are also investigated. The results show that the use of hot sewage or a heat pump for heat deliveries is beneficial only in combination with extended heat deliveries to an HM. Process integration measures are beneficial and even increase the benefit of selling more heat for district heating. Adding a condensing turbine unit is most beneficial in combination with extended heat deliveries and process integration. Copyright (c) 2007 John Wiley & Sons, Ltd.

  • 32.
    Larsson, Mikael
    et al.
    Department of Applied Physics and Mechanical Engineering, Luleå University of Technology, Sweden.
    Sandberg, Peter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Dahl, Jan
    Department of Applied Physics and Mechanical Engineering, Luleå University of Technology, Sweden.
    Söderström, Mats
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Vourinen, H.
    SSAB Tunnplåt AB, Luleå, Sweden.
    System gains from widening the system boundaries: analysis of the material and energy balance during renovation of a coke oven battery2004Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 28, nr 12, s. 1051-1064Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The coke oven plant has a central role in the iron and steel making process in an integrated steel plant. The subject of this research is to study how the production and energy system at the steel industry, with a connected combined heat and power plant, is affected by renovation of the coke oven. The aim is to investigate the interaction between the different processes and how the choice of system boundary affects the operation practice for the steel plant. MILP-based optimization models have been developed and used for the evaluation. The analysis shows that it is very important to take the interactions between the different production units in the system into consideration when making the analysis. A system optimization with a boundary including the whole system has a greater potential for minimizing the total system cost than one that only includes the processes where the actual changes are made. Conclusions are also drawn regarding the production practice for the specific system.

  • 33. Larsson, Mikael
    et al.
    Sandberg, Peter
    Division of Energy Systems, Department of Mechanical Engineering, Linköping Institute of Technology.
    Dahl, Jan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Söderström, Mats
    Division of Energy Systems, Department of Mechanical Engineering, Linköping Institute of Technology.
    Vuorinen, Henrik
    SSAB Tunnplåt AB.
    System gains from widening the system boundaries: analysis of the material and energy balance during renovation of a coke oven battery2004Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 28, nr 10, s. 1051-1064Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The coke oven plant has a central role in the iron and steel making process in an integrated steel plant. The subject of this research is to study how the production and energy system at the steel industry, with a connected combined heat and power plant, is affected by renovation of the coke oven. The aim is to investigate the interaction between the different processes and how the choice of system boundary affects the operation practice for the steel plant. MILP-based optimization models have been developed and used for the evaluation. The analysis shows that it is very important to take the interactions between the different production units in the system into consideration when making the analysis. A system optimization with a boundary including the whole system has a greater potential for minimizing the total system cost than one that only includes the processes where the actual changes are made. Conclusions are also drawn regarding the production practice for the specific system

  • 34. Leduc, Sylvain
    et al.
    Schwab, Dagmar
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Schmid, Erwin
    Obersteiner, Michael
    Optimal location of wood gasification plants for methanol production with heat recovery2008Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, nr 12, s. 1080-1091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Second generation biofuels from wood gasification are thought to become competitive in the face of effective climate and energy security policies. Cost competitiveness crucially depends on the optimization of the entire supply chain-field-wheel involving optimal location, scaling and logistics. In this study, a linear mixed integer programming model has been developed to determine the optimal geographic locations and sizes of methanol plants and gas stations in Austria. Optimal locations and sizes are found by the minimization of costs with respect to biomass and methanol production and transport, investments for the production plants and the gas stations. Hence, the model covers competition in all levels of a biofuel production chain including supply of biomass, biofuel and heat, and demand for bio- and fossil fuels. The results show that Austria could be self-sufficient in the production of methanol for biofuels like M5, M10 or M20, using up to 8% of the arable land share. The plants are optimally located close to the potential supply of biomass (i.e. poplar) in Eastern Austria, and produce methanol around 0.4 is an element of(-1). Moreover, heat production could lower the methanol cost by 12%.

  • 35.
    Leduc, Sylvain
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. International Institute for Applied Systems Analysis, Laxenburg, Austria.
    Schwab,, Dagmar
    University of Natural Resources and Applied Life Sciences, Vienna.
    Dotzauer, Erik
    Mälardalen University.
    Schmid, Erwin
    University of Natural Resources and Applied Life Sciences, Vienna.
    Obersteiner, Michael
    International Institute for Applied System Analysis (IIASA), Laxenburg.
    Optimal location of wood gasification plants for methanol production with heat recovery2008Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, nr 12, s. 1080-1091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Second generation biofuels from wood gasification are thought to become competitive in the face of effective climate and energy security policies. Cost competitiveness crucially depends on the optimization of the entire supply chain-field-wheel involving optimal location, scaling and logistics. In this study, a linear mixed integer programming model has been developed to determine the optimal geographic locations and sizes of methanol plants and gas stations in Austria. Optimal locations and sizes are found by the minimization of costs with respect to biomass and methanol production and transport, investments for the production plants and the gas stations. Hence, the model covers competition in all levels of a biofuel production chain including supply of biomass, biofuel and heat, and demand for bio- and fossil fuels.The results show that Austria could be self-sufficient in the production of methanol for biofuels like M5, M10 or M20, using up to 8% of the arable land share. The plants are optimally located close to the potential supply of biomass (i.e. poplar) in Eastern Austria, and produce methanol around 0.4 is an element of(-1). Moreover, heat production could lower the methanol cost by 12%.

  • 36.
    Leong, W.H.
    et al.
    Dept. of Mechanical/Industrial Eng., Ryerson University, 350 Victoria Street, Toronto, Ont. M5B 2K3, Canada.
    Tarnawski, V.R.
    Division of Engineering, Saint Mary's University, Halifax, NS B3H 3C3, Canada.
    Gori, F.
    Department of Mechanical Engineering, University of Rome Tor Vergata, 00133 Rome, Italy.
    Buchan, G.D.
    Soil and Physical Sciences Group, Lincoln University, P.O. Box 84, Canterbury, New Zealand.
    Sundberg, J.
    Swedish Geotechnical Institute, SE-581 93 Linkoping, Sweden.
    Inter-particle contact heat transfer model: An extension to soils at elevated temperatures2005Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 29, nr 2, s. 131-144Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A simple 'inter-particle contact heat transfer' model for predicting effective thermal conductivity of soils at moderate temperatures (0-30°C) has been extended up to 90°C. The extended model accounts for latent heat transport by water vapour diffusion in soil air above the permanent wilting point, below that point, the soil thermal conductivity is approximated by linear interpolation without latent heat effect. By and large the best results are obtained when the latent heat is used only in the 'self consistent approximation' model with an overall root mean square error of 35% for all soils under consideration or 26% when excluding volcanic soils. This option can also be applied to moderate temperatures at which the enhanced heat transfer is negligibly small. Copyright © 2005 John Wiley & Sons, Ltd.

  • 37.
    Leung, Dennis Y. C.
    et al.
    Univ Hong Kong.
    Yang, Hongxing
    Hong Kong Polytech Univ.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Novel studies on hydrogen, fuel cell and battery energy systems2011Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 35, nr 1, s. 1-1Artikel i tidskrift (Övrigt vetenskapligt)
  • 38. Leung, Dennis Y. C.
    et al.
    Yang, Hongxing
    Yan, Jinyue
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Novel studies on hydrogen, fuel cell and battery energy systems2011Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 35, nr 1, s. 1-1Artikel i tidskrift (Refereegranskat)
  • 39.
    Li, H.
    et al.
    Royal Institute of Technology, Sweden.
    Ji, X.
    Royal Institute of Technology, Sweden.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Royal Institute of Technology, Sweden.
    A new modification on RK EOS for gaseous CO2 and gaseous mixtures of CO2 and H2O2006Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 30, nr 3, s. 135-148Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To develop an equation of state with simple structure and reasonable accuracy for engineering application, Redlich-Kwong equation of state was modified for gaseous CO2 and CO2-H2O mixtures. In the new modification, parameter a of gaseous CO2 was regressed as a function of temperature and pressure from recent reliable experimental data in the range: 220-750 K and 0.1-400 MPa. Moreover, a new mixing rule was proposed for gaseous CO2-H2O mixtures. To verify the accuracy of the new modification, densities were calculated and compared with experimental data. The average error is 1.68% for gaseous CO2 and 0.93% for gaseous mixtures of CO2 and H2O. Other thermodynamic properties, such as enthalpy and heat capacities of CO2 and excess enthalpy of gaseous CO2-H2O mixtures, were also calculated; results fit experimental data well, except for the critical region.

  • 40.
    Li, H.
    et al.
    Royal Institute of Technology.
    Ji, Xiaoyan
    Yan, Jinyue
    Kungliga tekniska högskolan, KTH.
    A new modification on RK EOS for gaseous CO2 and gaseous mixtures of CO2 and H2O2006Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 30, s. 135-148Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To develop an equation of state with simple structure and reasonable accuracy for engineering application, Redlich-Kwong equation of state was modified for gaseous CO2 and CO2-H2O mixtures. In the new modification, parameter a of gaseous CO2 was regressed as a function of temperature and pressure from recent reliable experimental data in the range: 220-750 K and 0.1-400 MPa. Moreover, a new mixing rule was proposed for gaseous CO2-H2O mixtures. To verify the accuracy of the new modification, densities were calculated and compared with experimental data. The average error is 1.68% for gaseous CO2 and 0.93% for gaseous mixtures of CO2 and H2O. Other thermodynamic properties, such as enthalpy and heat capacities of CO2 and excess enthalpy of gaseous CO2-H2O mixtures, were also calculated; results fit experimental data well, except for the critical region.

  • 41.
    Li, Hailong
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Ji, Xiaoyan
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Yan, Jinyue
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    A new modification on RK EOS for gaseous CO2 and gaseous mixtures of CO2 and H2O2006Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 30, nr 3, s. 135-148Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To develop an equation of state with simple structure and reasonable accuracy for engineering application, Redlich-Kwong equation of state was modified for gaseous CO2 and CO2-H2O mixtures. In the new modification, parameter 'a' of gaseous CO2 was regressed as a function of temperature and pressure from recent reliable experimental data in the range: 220-750 K and 0.1-400 MPa. Moreover, a new mixing rule was proposed for gaseous CO2-H2O mixtures. To verify the accuracy of the new modification, densities were calculated and compared with experimental data. The average error is 1.68% for gaseous CO2 and 0.93% for gaseous mixtures of CO2 and H2O, Other thermodynamic properties, such as enthalpy and heat capacities of CO2 and excess enthalpy of gaseous CO2-H2O mixtures, were also calculated; results fit experimental data well, except for the critical region.

  • 42.
    Lu, Yuzheng
    et al.
    Southeast Univ, Sch Energy & Environm, Nanjing 210096, Jiangsu, Peoples R China.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Wang, Jun
    Southeast Univ, Sch Energy & Environm, Nanjing 210096, Jiangsu, Peoples R China.
    Zhang, Yaoming
    Southeast Univ, Sch Energy & Environm, Nanjing 210096, Jiangsu, Peoples R China.
    Li, Junjiao
    Bengbu Inst Business & Technol, Dept Comp Sci, Bengbu 233719, Anhui, Peoples R China.
    Hybrid Power Generation System of Solar Energy and Fuel Cells2016Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, International Journal of Energy Research, Vol. 40, nr 6, s. 717-725Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper introduces the methods of integration of solar energy and low-temperature solid oxide fuel cells. On the one hand, we design the system that integrates the solar photovoltaic cells and fuel cells. On the other hand, solar energy is concentrated to heat up the fuel cell and supply the working temperature at hundreds Celsius degrees by Fresnel lens. Then the fuel conversion efficiency is increased because of gain from the solar energy. Moreover, integration of solar thermal energy power system with the fuel is a good method for resolving the instability of solar energy. CHP (combined heat and power) is another aspect to enhance the design hybrid system overall efficiency. Finally, we present a novel device but built on different scientific principle. It can convert solar energy and chemical energy of fuel to electric energy simultaneously within the same device to integrated solar cell and fuel cell from the device level.

  • 43.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Kourosh
    A novel study on the power transformer losses in relation to CO2 capturing technology2008Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, nr 12, s. 1151-1163Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transformers are complex devices consisting of an iron core around which are wrapped various coils of insulated wires, inside a tank filled with insulating oil, along with connectors, bushings and various other small components. Overloading causes excess heat in a transformer, the negative effects of which are degradation of the kraft paper insulation around the wires (leading to internal failures of the coils), excessive tank pressure or degradation of the insulating oil (either of which can cause catastrophic failures, even explosions), and leaking gaskets and seals. (Since the copper used in the windings is already soft (annealed) and is not under tension, overheating of the conductors is generally not a concern.) Thermal cycling contributes to mechanical damage by loosening connections. Because of hysteresis in the transformer core, overloading generates harmonics and these can cause mechanical vibration of the transformer, contributing to physical damage. Overloading also assumes that faults near the transformer, when they occur, will be greater than normal, so there is the increased likelihood of damage to the transformer from fault currents; such damage can be manifested by coil failures, bushing flashovers, blown gaskets and seals, connector failures, oil explosions and fires, and physical displacement of internal components due to electromechanical torques. In addition, the world consumes millions of barrels of oils to cover the electrical losses, which then produces green house gases. With the introduction of new method for loss reduction, authors found a new method that is presented in this paper. In this paper we assess the impact of losses on final cost of transformer and green house gases. It is proved that losses cost is equal to the capital investment of the transformer. Emissions of CO2 in the electrical network is 0.4 kg CO2 kWh-1, which is (11 500 billion kilowatts hours of electricity produced) around 46 billion tons of transformer losses. This can be reduced to 23 billion ton using loss management. It is obvious that to cover losses generation of extra electricity is needed. Extra production leads to more CO2 emission. Installation of CO2 capturing device utilities at least can prevent more pollution emissions. For these reasons, a CO2 capturing condenser applicable in power station is presented here. It was simulated using COMSOL software. Copyright © 2008 John Wiley & Sons, Ltd.

  • 44.
    Naqvi, Salman Raza
    et al.
    Natl Univ Sci & Technol NUST, Sch Chem & Mat Engn, Islamabad, Pakistan..
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Catalytic fast pyrolysis of rice husk: Influence of commercial and synthesized microporous zeolites on deoxygenation of biomass pyrolysis vapors2018Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 42, nr 3, s. 1352-1362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research on utilization of abundant rice residue for valuable bioenergy products is still not explored completely. A simple, robust, cheap, and one-step fast pyrolysis reactor is still a key demand for production of bioenergy products, ie, high quality bio-oil and biochar. Bio-oil extracted from fast pyrolysis does not have adequate quality (eg, acidic and highly oxygenated). Catalytic fast pyrolysis using zeolites in the fast pyrolysis process effectively reduces the oxygen content (no H-2 required). In this paper, the zeolites with different pore sizes and shapes (small pore, SAPO-34 (0.56) and ferrierite (30); medium pore, ZSM-5 (30), MCM-22 (30), and ITQ-2 (30); and large pore zeolite, mordenite (30)) were tested in a drop-type fixed-bed pyrolyzer. Catalytic deoxygenation is conducted at 450 degrees C at the catalyst/biomass ratio of 0.1. Zeolite catalysts, its pore size and shape, could influence largely on deoxygenation. It was found that the small pore zeolites did not produce aromatics as compared to higher amount of aromatics formed in case of medium pore zeolites. ZSM-5 and ITQ-2 zeolites were especially efficient for the higher deoxygenation of biomass pyrolysis vapors due to better pore dimension and higher acidity.

  • 45.
    Naqvi, Salman Raza
    et al.
    Natl Univ Sci & Technol NUST, Sch Chem & Mat Engn, Islamabad, Pakistan..
    Naqvi, Muhammad
    Malardalen Univ, Sch Business Soc & Engn, Vasteras, Sweden..
    Catalytic fast pyrolysis of rice husk: Influence of commercial and synthesized microporous zeolites on deoxygenation of biomass pyrolysis vapors2018Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 42, nr 3, s. 1352-1362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research on utilization of abundant rice residue for valuable bioenergy products is still not explored completely. A simple, robust, cheap, and one-step fast pyrolysis reactor is still a key demand for production of bioenergy products, ie, high quality bio-oil and biochar. Bio-oil extracted from fast pyrolysis does not have adequate quality (eg, acidic and highly oxygenated). Catalytic fast pyrolysis using zeolites in the fast pyrolysis process effectively reduces the oxygen content (no H-2 required). In this paper, the zeolites with different pore sizes and shapes (small pore, SAPO-34 (0.56) and ferrierite (30); medium pore, ZSM-5 (30), MCM-22 (30), and ITQ-2 (30); and large pore zeolite, mordenite (30)) were tested in a drop-type fixed-bed pyrolyzer. Catalytic deoxygenation is conducted at 450 degrees C at the catalyst/biomass ratio of 0.1. Zeolite catalysts, its pore size and shape, could influence largely on deoxygenation. It was found that the small pore zeolites did not produce aromatics as compared to higher amount of aromatics formed in case of medium pore zeolites. ZSM-5 and ITQ-2 zeolites were especially efficient for the higher deoxygenation of biomass pyrolysis vapors due to better pore dimension and higher acidity.

  • 46.
    Perez de la Mora, Nicolas
    et al.
    Universidad de las Islas Baleares.
    Bava, Federico
    Technical University of Denmark.
    Andersen, Martin
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. Chalmers University of Technology.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lennermo, Gunnar
    Mälardalens Hogskola.
    Nielsen, Christian
    PanEnergi.
    Furbo, Simon
    Technical University of Denmark.
    Martínes-Moll, Víctor
    Universidad de las Islas Baleares.
    Solar district heating and cooling: A review2017Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, s. 1-23Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Both district heating and solar collector systems have been known and imple- mented for many years. However, the combination of the two, with solar collec- tors supplying heat to the district heating network, is relatively new, and no comprehensive review of scientific publications on this topic could be found. Thus, this paper summarizes the literature available on solar district heating and presents the state of the art and real experiences in this field. Given the lack of a generally accepted convention on the classification of solar district heating systems, this paper distinguishes centralized and decentralized solar district heating as well as block heating. For the different technologies, the paper describes commonly adopted control strategies, system configurations, types of installation, and integration. Real‐world examples are also given to provide a more detailed insight into how solar thermal technology can be integrated with district heating. Solar thermal technology combined with thermally driven chillers to provide cooling for cooling networks is also included in this paper. In order for a technology to spread successfully, not only technical but also eco- nomic issues need to be tackled. Hence, the paper identifies and describes dif- ferent

  • 47.
    Perez-Mora, Nicolas
    et al.
    Univ Illes Balears, Palma De Mallorca, Illes Balears, Spain..
    Bava, Federico
    Danmarks Tekniske Univ, Dept Civil Engn, Lyngby, Denmark..
    Andersen, Martin
    Högsk Dalarna Falun Dalarna, Falun, Sweden..
    Bales, Chris
    Dalarna Univ Coll, Borlänge, Sweden..
    Lennermo, Gunnar
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nielsen, Christian
    PlanEnergi, Copenhagen, Denmark..
    Furbo, Simon
    Danmarks Tekniske Univ, Dept Civil Engn, Lyngby, Denmark..
    Martinez-Moll, Victor
    Univ Illes Balears, Palma De Mallorca, Illes Balears, Spain..
    Solar district heating and cooling: A review2018Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 42, nr 4, s. 1419-1441Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Both district heating and solar collector systems have been known and implemented for many years. However, the combination of the two, with solar collectors supplying heat to the district heating network, is relatively new, and no comprehensive review of scientific publications on this topic could be found. Thus, this paper summarizes the literature available on solar district heating and presents the state of the art and real experiences in this field. Given the lack of a generally accepted convention on the classification of solar district heating systems, this paper distinguishes centralized and decentralized solar district heating as well as block heating. For the different technologies, the paper describes commonly adopted control strategies, system configurations, types of installation, and integration. Real-world examples are also given to provide a more detailed insight into how solar thermal technology can be integrated with district heating. Solar thermal technology combined with thermally driven chillers to provide cooling for cooling networks is also included in this paper. In order for a technology to spread successfully, not only technical but also economic issues need to be tackled. Hence, the paper identifies and describes different types of ownership and financing schemes currently used in this field.

  • 48.
    Pettersson, Karin
    et al.
    RISE Research Institutes of Sweden, Samhällsbyggnad, Systemomställning och tjänsteinnovation.
    Axelsson, Erik
    Göteborg Energi AB, Sweden; Profu AB, Sweden.
    Eriksson, Lina
    RISE Research Institutes of Sweden, Samhällsbyggnad, Systemomställning och tjänsteinnovation.
    Svensson, Elin
    CIT Industriell Energi, Sweden.
    Berntsson, Thore
    Chalmers University of Technology, Sweden.
    Harvey, Simon
    Chalmers University of Technology, Sweden.
    Holistic methodological framework for assessing the benefits of delivering industrial excess heat to a district heating network2020Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    In Sweden, over 50% of building heating requirements are covered by district heating. Approximately 8% of the heat supply to district heating systems comes from excess heat from industrial processes. Many studies indicate that there is a potential to substantially increase this share, and policies promoting energy efficiency and greenhouse gas emissions reduction provide incentives to do this. Quantifying the medium and long-term economic and carbon footprint benefits of such investments is difficult because the background energy system against which new investments should be assessed is also expected to undergo significant change as a result of the aforementioned policies. Furthermore, in many cases, the district heating system has already invested or is planning to invest in non-fossil heat sources such as biomass-fueled boilers or CHP units. This paper proposes a holistic methodological framework based on energy market scenarios for assessing the long-term carbon footprint and economic benefits of recovering excess heat from industrial processes for use in district heating systems. In many studies of industrial excess heat, it is assumed that all emissions from the process plant are allocated to the main products, and none to the excess heat. The proposed methodology makes a distinction between unavoidable excess heat and excess heat that could be avoided by increased heat recovery at the plant site, in which case it is assumed that a fraction of the plant emissions should be allocated to the exported heat. The methodology is illustrated through a case study of a chemical complex located approximately 50 km from the city of Gothenburg on the West coast of Sweden, from which substantial amounts of excess heat could be recovered and delivered to heat to the city's district heating network which aims to be completely fossil-free by 2030. © 2020 The Authors.

  • 49.
    Pettersson, Karin
    et al.
    RISE - Research Institutes of Sweden, Samhällsbyggnad, Energi och cirkulär ekonomi. Chalmers University of Technology, Sweden.
    Lundberg, Valeria
    RISE - Research Institutes of Sweden, Bioekonomi.
    Anheden, Marie
    RISE - Research Institutes of Sweden, Bioekonomi, Bioraffinaderi och energi.
    Fuglesang, Malin
    ÅF Industry, Sweden.
    Systems analysis of different value chains based on domestic forest biomass for the production of bio-SNG2018Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 42, nr 6, s. 2117-2140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study compares value chains based on domestic forest biomass for the production of bio-synthetic natural gas (SNG) with respect to economic performance, GHG emissions, and energy efficiency. Value chains in which raw material is upgraded to intermediate products before transportation to an SNG plant integrated with a district heating system for further upgrading are compared with a chain in which the raw material is transported directly to the SNG plant. The intermediates considered are either dried biomass from forest residues, or bark, upgraded at pulp mills, or pellets from sawdust upgraded at sawmills. The findings show that the difference in performance between the studied value chains is generally small. The highest cost and significantly lowest energy efficiency are associated with the value chain with pellets, which leads to the conclusion that more pretreatment than what is required by the SNG process, to lower transport costs, is not profitable. Drying forest residues at pulp mills before further transportation to and upgrading at an SNG plant leads to somewhat higher transportation costs because of the relatively high fixed costs associated with transportation. However, the benefit of drying the biomass using excess heat at pulp mills is that heat is "moved" from a location, where it can be hard to find profitable ways to use it, to the SNG plant, where the excess heat can be used for district heating. With these two factors working in opposition, the total cost is similar if forest residues are transported directly to the SNG plant or via a pulp mill. The lowest cost is achieved when falling bark from pulp mills is used because the first transportation step is avoided and no additional investment for biomass handling at the mill is required. However, there is a technical uncertainty regarding how much bark can be used in the SNG process.

  • 50.
    Raza, Rizwan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Ahmad, M. Ashfaq
    Iqbal, Javed
    Akram, N.
    Gao, Zhan
    Javed, Sufyan
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Ce-0.8(SmZr)(0.2)O-2-carbonate nanocomposite electrolyte for solid oxide fuel cell2014Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 38, nr 4, s. 524-529Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A nanocomposite Zr/Sm-codoped ceria electrolyte coated with K2CO3/Na2CO3 was synthesized by a coprecipitation method. The electrochemical study of the two-phase nanocomposite electrolytes with carbonate coated on the doped ceria shows high oxygen ion mobility at low temperatures (300-600 degrees C). The interface between the two constituent phases was studied by electrochemical impedance spectroscopy. Ionic conductivities were also measured with electrochemical impedance spectroscopy. The morphology and structure of composite electrolyte were characterized using field-emission scanning electron microscopy and X-ray diffraction. The fuel cell power density is 700 mW cm(-2), and an open-circuit voltage of 1.00 V is achieved at low temperatures (400-550 degrees C). This codoped approach with a second phase provides a good indication regarding overcoming the challenges of solid oxide fuel cell technology.

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