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  • 251.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Grimm, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Ash transformation chemistry during energy conversion of biomass2010In: Impacts of Fuel Quality on Power Production & Environment: 29/08/2010 - 03/09/2010, Impacts of Fuel Quality , 2010Conference paper (Refereed)
    Abstract [en]

    There is relatively extensive knowledge available concerning ash transformation reactions during energy conversion of woody biomass. Traditionally, these assortments have constituted the main resources for heating in Sweden. In recent decades the utilization of these energy carriers has increased, from a low technology residential small scale level to industrial scale (e.g. CHP plants). Along this evolution ash-chemical related phenomena for woody biomass has been observed and studied. So, presently the understanding for these are, if not complete, fairly good. Briefly, from a chemical point of view the ash from woody biomass could be characterized as a silicate dominated systems with varying content of basic oxides and with relatively high degree of volatilization of alkali sulfates and chlorides. Thus, the main ash transformation mechanisms in these systems have been outlined. Here, an attempt to give a general description of the ash transformation reactions of biomass fuels is presented, with the intention to provide guidance in the understanding of ash matter behavior in the utilization of any biomass fuel, primarily from knowledge of the concentrations of ash forming elements but also by considering the physical condition in the specific combustion appliance and the physical characteristic of the biomass fuel. Furthermore, since the demand for CO2-neutral energy resources has increased the last years and will continue to do so in the foreseeable future, other biomasses as for instance agricultural crops has become highly interesting. Globally, the availability of these shows large variation. In Sweden, for instance, which is a relatively spare populated country with large forests, these bio-masses will play a secondary role, although not insignificant. In other parts of the world, more densely populated and with a large agricultural sector, such bio-masses may constitute the main energy bio-mass resource in the future. However, the content of ash forming matter in agricultural bio-mass is rather different in comparison to woody biomass. Firstly, the content is much higher; from being about 0.3 – 0.5% (wt) in stem wood, it can amount to between 2 and 10 %(wt) in agricultural biomass. In addition, the composition of the ash forming matter is different. Shortly, the main difference is due to a much higher content of phosphorus (occasionally also silicon) which has major consequences on the ash-transformation reactions. In many crops, the concentration of phosphorus and silicon is equivalent, which (depending on the concentration levels of basic oxides) may result in a phosphate dominated ash. The properties of this ash are in several aspects different from the silicate dominated woody biomass ash and will consequently behave differently in various types of energy conversion systems. The knowledge about phosphate dominated ash systems has so far been scarce. We have been working with these systems, both with basic and applied research, for about a decade know. Some general experiences and conclusions as well as some specific examples of our research will be presented.

  • 252.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Eriksson, Gunnar
    Division of Energy Engineering, Department of Applied Physics and Mechanical Engineering, Luleå Technical University.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Division of Energy Engineering, Department of Applied Physics and Mechanical Engineering, Luleå Technical University.
    Ash transformations in fluidized-bed combustion of rapeseed meal2009In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, no 5, p. 2700-2706Article in journal (Refereed)
    Abstract [en]

    The global production of rapeoil is increasing. A byproduct is rapeseed meal that is a result of the oil extraction process. Presently the rapeseed meal mainly is utilized as animal feed. An interesting alternative use is, however, energy conversion by combustion. This study was undertaken to determine the combustion properties of rapeseed meal and bark mixtures in a bubbling fluidized bed, with emphasis on gas emissions, ash formation, -fractionation and -interaction with the bed material. Due to the high content of phosphorus in rapeseed meal the fuel ash is dominated by phosphates, in contrast to most woody biomass where the ash is dominated by silicates. From a fluidized bed combustion (FBC) point of view, rapeseed meal could be a suitable fuel. Considering FBC agglomeration effects, pure rapeseed meal is in level with the most suitable fuels, as earlier tested by the methods utilized in the present investigation. The SO2 emission, however, is higher than most woody biomass fuels as a direct consequence of the high levels of sulfur in the fuel. Also the particulate matter emission, both submicron and coarser particles, is higher. Again this can be attributed the high ash content of rapeseed meal. The high abundance of SO2 is apparently effective for sulfatization of KCl in the flue gas. Practically no KCl was observed in the particulate matter of the flue gas. A striking difference in the mechanisms of bed agglomeration for rapeseed meal compared to woody biomass fuels was also observed. The ubiquitous continuous layers on the bed grains found in FBC combustion of woody biomass fuels was not observed in the present investigation. Instead very thin and discontinuous layers were observed together with isolated partly melted bed ash particles. The latter could occasionally be seen as adhered to the quartz bed grains. Apparently the bed agglomeration mechanism, that obviously demanded rather high temperatures, involved more of adhesion by partly melted ash derived potassium -calcium phosphate bed ash particles/droplets than direct attack of gaseous alkali on the quartz bed grains forming potassium -calcium silicate rich bed grain layers. Am explanation could be found in the considerable higher affinity for base cations of phosphorus than silicon. This will to a great extent withdraw the present basic oxides from attacking the quartz bed grains with agglomeration at low temperatures as a result.

  • 253.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Grimm, Alejandro
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Björnbom, Emilia
    Chemical Engineering and Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Öhman, Marcus
    Division of Energy Engineering, Luleå University of Technology, SE- 971 87 Luleå, Sweden.
    Influence of kaolin and calcite additives on ash transformations in small-scale combustion of oat2009In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, no 10, p. 5184-5190Article in journal (Refereed)
    Abstract [en]

    A growing interest has been observed for the use of cereal grains in small- and medium-scale heating. Previous studies have been performed to determine the fuel quality of various cereal grains for combustion purposes. The present investigation was undertaken in order to elucidate the potential abatement of low-temperature corrosion and deposits formation by using fuel additives (calcite and kaolin) during combustion of oat. Special emphasis was put on understanding the role of slag and bottom ash composition on the volatilization of species responsible for fouling and emission of fine particles and acid gases. The ash fractions were analyzed with scanning electron micro scopy/energy dispersive spectroscopy (SEM/EDS), for elemental composition, and with X-ray diffraction (XRD) for identification of crystalline phases. The previously reported K and Si capturing effects of kaolin additive were observed also in the present study using P-rich biomass fuels. That is, the prerequisites for the formation of low melting K-rich silicates were reduced. The result of using kaolin additive on the bottom ash was that no slag was formed. The effect of the kaolin additive on the formation of submicrometer flue gas particles was an increased share of condensed K-phosphates at the expense of K-sulfate and KCl. The latter phase was almost completely absent in the particulate matter. Consequently, the levels of HCl and SO2 in the flue gases increased somewhat. The addition of both calcite assortments increased the amount of farmed slag, although to a considerably higher extent for the precipitated calcite. P was captured to a higher degree in the bottom ash, compared to the combustion of pure oat. The effect of the calcite additives on the fine particle emissions in the flue gases was that the share of K-phosphate decreased considerably, while the content of K-sulfate and KCl increased. Consequently, also the flue-gas levels of acidic HCl and SO2 decreased. This implies that the low-temperature corrosion observed in small-scale combustion of oat possibly can be abated by employing calcite additives. Alternatively, if problems with slagging and deposition of corrosive matter at heat convection surfaces are to be avoided, kaolin additive can be utilized, on the condition that the higher concentrations of acidic gases can be tolerated.

  • 254.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ash transformation chemistry during combustion of biomass, theory and technical applications2017In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 254Article in journal (Other academic)
  • 255.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Grimm, Alejandro
    Luleå Univ Technol, Div Energy Sci, SE-97187 Luleå, Sweden.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå Univ Technol, Div Energy Sci, SE-97187 Luleå, Sweden.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ash Transformation Chemistry during Combustion of Biomass2012In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 26, no 1, p. 85-93Article in journal (Refereed)
    Abstract [en]

    There is relatively extensive knowledge available concerning ash transformation reactions during combustion of woody biomass. In recent decades, the use of these energy carriers has increased, from a low-technology residential small-scale level to an industrial scale. Along this evolution, ash chemical-related phenomena for woody biomass have been observed and studied. Therefore, presently the understanding for these are, if not complete, fairly good. However, because the demand for CO2-neutral energy resources has increased recently and will continue to increase in the foreseeable future, other biomasses, such as, for instance, agricultural crops, have become highly interesting. The ash-forming matter in agricultural biomass is rather different in comparison to woody biomass, with a higher content of phosphorus as a distinctive feature. The knowledge about the ash transformation behavior in these systems is far from complete. Here, an attempt to give a schematic but general description of the ash transformation reactions of biomass fuels is presented in terms of a conceptual model, with the intention to provide guidance in the understanding of ash matter behavior in the use of any biomass fuel, primarily from the knowledge of the concentrations of ash-forming elements. The model was organized in primary and secondary reactions. Restrictions on the theoretical model in terms of reactivity limitations and physical conditions of the conversion process were discussed and exemplified, and some principal differences between biomass ashes dominated by Si and P, separately, were outlined and discussed.

  • 256.
    Boström, Jesper
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Blockritningar och dess användning i produktion2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The project is an investigation for a new method creating blueprints for in-fill walls. The original purpose of the project was only to make a comparison between different types of methods creating these blueprints. During the beginning of the work I realized that it is hard to learn how to perform the new method, and therefore I have created a guide about the procedure of the work with the new method. This project is made in cooperation together with a construction company called Peab. The idea is that the blueprints for the in-fill walls in one of Peabs upcoming constructions are going to be created with the new method.

    The purpose with this work is to compare different type of methods creating blueprints for in-fill walls. The comparison is made for the three methods, AutoCAD, Revit and blueprints made by hand. The purpose with this project has also been to create a guide for the procedure of the work in Revit.

    The first part is a study that describes the subjects in this project. The internet and literature has been used for gathering information. The second part is the comparison. The result has been compared in the categories entry requirement, running time, equipment requirement, clarity/ accuracy of the blueprints and the information that is gained in the blueprints. The third and last part is the result of the guide, which is divided into six steps. Each step is described in words and with illustrations from Revit.

    The work is written in Swedish.

  • 257.
    Boström, Oskar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Metodik för högupplöst 3D-skanning av traktorer2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor thesis on 3D-scanning includes a survey of the leading handheld scanners that are avaliable on the market today, together with two methodology parts. The client, Ålö, is a market leader in developing and manufacturing front loaders for the agricultural sector.  The 3D scanning technology will primarily be used to scan tractors that not yet have  a subframe to attach frontloaders on.

     

    The target with the benchmarking has been used to determine which one of the scanners, avaliable on the market today, that will fit Ålö’s needs and requirements best. Thus a number of criterias have been choosen in cooperation with the staff at Ålö and the scanners have been benchmarked towards these criterias.

     

    The methodology parts have basically been a large  number of practical tests in the basis before the necessary information were able to set through. These tests have been carried out in the factory at Ålö. To conduct these tests a variety of different objects had to be scanned to test the reliability. These objects are among others a free hanging subframe and a tractor with an already installed base.

     

    The aim with a good 3D scanning technology is to get competitive advantages versus other manufacturers competing on the same market as Ålö. This new technology will give faster time to market for new subframes, with increased quality, which in turn hopefully will increase sales of Ålö’s frontloaders.

  • 258. Bozaghian, Marjan
    et al.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Thyrel, Mikael
    Xiong, Shaojun
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering, S-971 87 Luleå, Sweden.
    Combustion characteristics of straw stored with CaCO3 in bubbling fluidized bed using quartz and olivine as bed materials2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 212, p. 1400-1408Article in journal (Refereed)
    Abstract [en]

    The addition of Ca-containing compounds can reduce mass loss from agricultural biomass during storage. The resulting alkaline environment is detrimental to microorganisms present in the material. Theoretical analysis of Ca-containing biomass suggests that combustion properties are improved with respect to slagging. To validate the theoretical calculations, barley straw was utilized as a typical model agricultural biomass and combustion characteristics of straw pre-treated with 2 and 4 w/w% CaCO3 for combined improvement of storage and combustion properties were determined through combustion at 700 degrees C in a bench-scale bubbling fluidized-bed reactor (5 kW) using quartz and olivine sand as bed materials. The combustion characteristics were determined in terms of elemental composition and compound identification in bed ash and bed material including agglomerates, fly ash, particulate matter as well as flue gas measurements. The addition of CaCO3 to straw had both positive and negative effects on its combustion characteristics. Both additive levels raised the total de fluidization temperature for both quartz and olivine, and olivine proved to be less susceptible than quartz to reactions with alkali. With Ca-additives, the composition of deposits and fine particulate matter changed to include higher amounts of KCl potentially leading to higher risk for alkali chloride-induced corrosion. Flue gas composition was heavily influenced by CaCO3 additives by significantly elevated CO concentrations likely related to increased levels of gaseous alkali compounds. The results suggest that it is necessary to reduce gaseous alkali compounds, e.g. through kaolin or sulphur addition, if alkali-rich straw is to be co-combusted with Ca-rich biomass or large amounts of Ca-additives.

  • 259.
    Bozaghian, Marjan
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Xiong, Shaojun
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion characteristics of barley straw stored with CaCO3 using olivine and quartz as bed materials in fluidized bed combustion2017Conference paper (Refereed)
  • 260.
    Bozaghian, Marjan
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Xiong, Shaojun
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion characteristics of barley straw stored with CaCO3 using quartz and olivine as bed materials in fluidized-bed combustion2017Conference paper (Other academic)
  • 261.
    Brager, Eveliina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Dimensionering av limträstomme till Coop butik: med en miljöjämförelse mellan stommaterialen stål och limträ2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The construction process in Sweden generates ten million carbon dioxide equivalents per year. Actors involved in the construction industry needs to clarify the climate load of the construction process and increase the knowledge of it. In this paper an alternative frame in glulam has been designed for a grocery store with a steel frame. As the bearing beam has a tensed three joint truss been used with a range of 40 meter. This work also includes an environmental comparison between steel and glulam as frame material set out from the amount of steel and glulam used in the frames, 31 ton of steel compared with 150 m3 glulam. The environmental analyses have been done by using the Eco strategy wheel, that is a tool used for optimizing a product regarding the environment, and by identifying environmental aspects from the manufacturing of the materials. The environmental aspects were then associated with the sustainability principles and graded by extent, severity and frequency. The ambition of this project was to show that a glulam frame can carry loads as good as a steel frame and to increase the knowledge of persons involved in the construction process to choose materials that are good for the environment. The results show that it was possible to design a glulam frame for the store but with an increased building height and volume as a consequence. Both frames could carry the loads but had different qualities. When the use of energy in the manufacture process were compared it showed that the glulam frame used almost twice the amount of energy compared to the steel frame, but in the process of manufacturing glulam almost all energy used came from renewable sources while the manufacturing of steel uses almost only energy from non-renewable sources. The carbon dioxide emission of the steel frame was 170 ton more than of the glulam frame that instead binds carbon dioxide. In the production of the steel frame the steel consumes 600 m3 more fresh water than the glulam frame and the steel process generate more waste. The transport of the steel frame also generates more carbon dioxide than the transport of the glulam, much thanks to the nearness of material and supplier of glulam to the construction site. This shows that it is good for the environment to think local.

  • 262.
    Brajerski, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Stability design of multi-storey timber structures2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Stability design of buildings is an extremely important discipline within the field of structural engineering.

     

    This report demonstrates, with help of a worked example, the theory behind the stabilisation of multi-storey timber structures. The worked example is an existing 6-storey building, primarily made with cross laminated timber (CLT). The construction project is located in central Umeå and is designed and managed by Martinsons Byggsystem. The building uses an array of CLT wall panels as a stabilising system.

     

    A number of key points that will be looked at in the worked example; firstly, analysing the loads acting on the building, specifically the calculation of lateral wind loads and their effect on stabilising CLT panels; secondly, a deeper look into the methods of stabilisation using CLT walls. This will include the stability checks for overturning, sliding and shear and counter measures taken against any potential instability. Finally, a look into how CLT walls can be designed by hand calculations according to Eurocodes. There is no particular predefined method to do this, so this report will show how to design a CLT wall by treating CLT as either a homogeneous material or a non-homogeneous/composite material.

  • 263.
    Branca, Carmen
    et al.
    Istituto di Ricerche sulla Combustione, C.N.R., P.le V. Tecchio, 80125 Napoli, Italy.
    Di Blasi, Colomba
    Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università degli Studi di Napoli “Federico II”, P.le V. Tecchio, 80125 Napoli, Italy.
    Galgano, Antonio
    Istituto di Ricerche sulla Combustione, C.N.R., P.le V. Tecchio, 80125 Napoli, Italy.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effects of the Torrefaction Conditions on the Fixed-Bed Pyrolysis of Norway Spruce2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 9, p. 5882-5891Article in journal (Refereed)
    Abstract [en]

    Fixed-bed pyrolysis of Norway spruce wood previously subjected to torrefaction at temperatures between 533 and 583 K and retention times between 8 and 25 min was studied. Although the thermal pretreatment always results in an increased production of char at the expense of volatile products, appropriate torrefaction conditions give rise to maximum percentages of anhydrosugars, guaiacols possessing a carbonyl group, and phenols in the liquid fraction. Other carbohydrates (e.g., acetic acid, formic acid, hydroxyacetaldehyde, hydroxypropanone, furfural, and furfuryl alcohol) and the large majority of guaiacols show continuously decreasing values. The percentages of carbon monoxide and carbon dioxide in the gas product remain approximately the same, but that of methane slightly increases. The pyrolysis temperatures of torrefied wood are lower than those of the raw material, mainly because of the partial or complete absence of the exothermic contribution associated with extractives and hemicellulose degradation.

  • 264.
    Breimark, Odd
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Undersökning av förutsättningar för icke-publik laddinfrastruktur2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is done as an assignment on behalf of Luleå Energi AB and Luleå Energi Elnät AB. It mainly concerns charging of Plug-in electric vehicles at corporations and apartment buildings. The object of this thesis is to investigate current requirements with these users and to investigate how services can be constructed to fulfil these requirements.

    To investigate the requirements of this non-public market a series of interviews were performed. A number of questions were constructed to use as ground during the interviews. Apart from the constructed questions, the interviewed were encouraged to express other opinions and questions concerning charging of electric vehicles. A large interest exists concerning this mater and several corporations are already offering charging although it also shows that a wider non-public infrastructure is required. The interviews also revealed that a wide spread of information is of importance and that charging with an ordinary home outlet (Schuko) is not to be recommended. All of the interviewed were of the opinion that more information from Luleå Energi would be of interest and that this would promote the expansion of electric vehicles.

    An extensive theory chapter was constructed to cover questions that may appear during the work of the thesis. This enabled a spread of information during the interviews. This chapter is meant to be used as information at Luleå Energi but could also be used as information to future clients. A number of criteria were constructed with the interviews and the theory chapter as foundation. These criteria were then given a weight of importance to present the aspects to bear in mind when implementing charge stations. The criteria that concerned standards and safety were the most important ones, along with the criteria of the impotence of an energy meter to every charging point. Criteria that where of importance but not as much as those mentioned earlier were limited access only to specific users, economical aspects, user friendly functions and effective payment systems. A confident ownership was of importance whereas some kind of service agreement could be of interest. Aspects of low importance were those connected to design but also the aspect that a connection for engine heaters is available.

    Charging of electric vehicles at apartment buildings and corporations will most likely not exceeded an output of 7.4 kW due to the fact that cars spend most of their time at parking spaces. These chargers could be complimented with chargers with a higher output up to 22 kW. The benefits of higher outputs appear when clients or workers spend a short time at a charging site. Quick chargers with outputs from 50 kW are rarely of economic benefit due to the high cost of the equipment and installation.

    A series of tests where concluded with a battery electric vehicle with the purpose to investigate energy consumption in Nordic winter climate. Temperature, travelled distance and energy consumption where the main parameters of the tests. The tests included both country road testing and city road testing. The tests resulted in a higher energy consumption and shorter range compared to the numbers presented from the car manufacturer. Despite this the test revealed that the range is enough in most of the cases with daily travel. The greatest advantages compared to fossil fuel vehicles appeared in city traffic where this particular vehicle could be driven in 3.5 hours without recharging. All together this reveals the economic and environmental advantages of driving a battery electric vehicle compared to a fossil fuel vehicle.

  • 265.
    Brembilla, Christian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Efficiency factors for space heating system in buildings2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The thesis focuses on the efficiency of the space heating system. In particular, the efficiency factors measure the efficiency of thermal zone. The efficiency factors measures how the energy is used in a space heating. Efficiency factors relatively close to one mean that the energy is used "efficiently'', by contrast, efficiency factors close to the zero mean that the majority of the energy is lost to the outdoor environment. This method for the appraisal of space heating performance reads as if it is apparently simple and intuitive. In reality, the efficiency factor method has several pitfalls.

    The thesis provides tools, insights and remarks on how to apply the efficiency factor method to space heating systems equipped with hydronic panel radiator and floor heating respectively. Models of the latter heaters together with the multilayer wall were developed and validated to understand the reliability of their predictions. The hypothesis is that the heat stored in the building thermal mass and heaters plays a role in defining the building thermal performance and as a result in the appraisal of the efficiency factors. The validation is based on the sensitivity bands of the models' predictions. The heaters were tested in in a thermostatic booth simulator. Benefits and drawbacks of each model were highlighted to increase awareness of their use in the engineering fields. The results showed how the models accounting for the heat stored performed the charging phase. In addition, results of how the multilayer wall delayed and damped down the heat wave coming from the outdoor environment were presented with the appraisal of the decrement factor and time delay of the indoor temperature. The results of the efficiency factors analysis reveal how the weather affects the efficiency of each locality situated in cold climates. Lastly how different control strategies impact on the efficiency factors of space heating and its distribution system. To conclude, this study highlights the paradoxes around the efficiency factor method. The thesis proposes how such factors have to be interpreted by researchers and scientists tackling the lack of information around this topic.

  • 266.
    Brembilla, Christian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Modelling and simulation of building components: thermal interaction between multilayer wall and hydronic radiator2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background and Scope The scope of this thesis is to investigate the thermal behaviour of building components as hydronic radiator and multilayer walls subjected to dynamic conditions. The modelling and simulation of these building components provide information on how these components thermally interact among each other. The thermal interaction is fundamental to know how the energy is used in buildings. In particular, the thermal energy used in rooms can be expressed as the efficiencies for emission in a space heating system. This thesis analyzes the efficiencies for emission of a space heating system equipped with hydronic radiator for Swedish buildings by providing a comprehensive and detailed approach on this topic.

     

    Methodology The methods used in this thesis are: experiment, modelling of multilayer wall and hydronic radiator, the dynamic simulation of the building and the efficiencies for emission of a space heating system. Here, the experiment, known as step response test, shows the heating up process of a hydronic radiator. The observation of the qualitative measurements suggests the most suitable technique of modelling the radiator known as transient modelling with multiple storage elements. The multilayer wall has been discretized both in space and time variable with a Finite Difference Method. Dynamic simulation of the building provides the efficiencies for emission of a space heating system.

     

    Findings The experimental results show how the radiator performs the charging phase. The performance of the transient model is compared with lumped steady state models in terms of temperature of exhaust flow and total heat emitted. Results of the dynamic simulation show how buildings located in a Northern climate use the energy in a better way than Southern climates in Sweden. Heavy active thermal mass provides higher efficiencies for emission than light thermal mass. Radiators with connection pipes located on the same side react faster at the thermodynamic changing of the mass flow rate by providing higher efficiencies for emission than radiators with connection pipes located on the opposite side.

     

    Conclusion and Outlook This thesis increases the knowledge about the modelling and simulation of hydronic radiators and multilayer walls. More research is needed on this topic to encompass modelling details of building components often ignored. The modelling and simulation of building components are the key to understand how building components thermally interact with each other. The thermal interaction among building components is a fundamental parameter for the assessment of efficiencies of emission of the space heating system. In the near future, the concept of efficiencies of emission can be implemented in National Building Code, therefore, this study provides guidelines on how to assess these efficiencies.

  • 267.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lacoursiere, Claude
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Investigation of thermal parameters addressed to a building simulation model2015In: Energy, Science and Technology 2015: Book of Abstracts. The energy conference for scientists and researchers / [ed] Karlsruher Institute of Technology (KIT), Karlsruher, Germany: Karlsruher Institute of Technology (KIT) , 2015, Vol. 1, p. 128-Conference paper (Refereed)
    Abstract [en]

    Introduction The uncertainty of setting input parameters in a building model can have a major impact on the simulated output. The tolerance of thermal parameters is a necessary information that helps modeler to know the influence of eachfactors on the outcomes. This paper shows the allowable tolerance of thermal parameters in order to build anaccurate building model.

  • 268.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lacoursiere, Claude
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Investigations of thermal parameters addressed to a building simulation model2015In: Proceedings of BS2015, India, Hyderabad: International Building Performance Simulation Association (IBPSA), 2015, , p. 2741-2748p. 2741-2748Conference paper (Refereed)
    Abstract [en]

    This paper shows the tolerance of thermal parameters addressed to a building simulation model in relation to the local control of the HVAC system. This work is suitable for a modeler that has to set up a building simulation model. The modeler has to know which parameter needs to be considered carefully and vice-versa which does not need deep investigations. Local differential sensitivity analysis of thermal parameters generates the uncertainty bands for the indoor air. The latter operation is repeated with P, PI and PID local control of the heating system. In conclusion, the local control of a room has a deterministic impact on the tolerance of thermal parameters.

  • 269.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    One dimensional model of transient heat conduction through multilayer walls/slabs: The functionality of insulation and brick materials in terms of decrement factor and time lag2016Manuscript (preprint) (Other academic)
    Abstract [en]

    Multilayer wall is a common type of building envelope used in buildings located in cold climates. The building envelope is typically composed by internal and external masses made by bricks or concrete separated by a large thickness of insulation material. This paper investigates the thermal behavior of a multilayer wall subjected to temperature excitation on both wall sides. The analysis is conducted by discretizing the continuous space and time variables of the mathematical model identified in the heat equation. Euler backwards solves the numerical model of multilayer wall by providing an unconditionally stable solution. The step response test shows the correct working of the model which reaches the steady state solution. The results of this paper are expressed in terms of temperature of each wall layer against the time. In particular, (i) the large thickness of insulation material separates thermodynamically the outside external mass from the internal mass, (ii) 20 cm thickness of insulation material damps the heat wave with a decrement factor of 3.41 °ͦC and a time lag of 1 hour, (iii) the external brick layer damps the heat wave with a decrement factor of 1.97 °ͦC and a time lag of 5 hours.

  • 270.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Renman, Ronny
    Östin, Ronny
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    The impact of control strategies on space heating system efficiency in low-energy buildings2018In: Building Services Engineering Research & Technology, ISSN 0143-6244, E-ISSN 1477-0849Article in journal (Refereed)
    Abstract [en]

    In this study efficiency factors measures the thermal energy performance for space heating. This study deals with the influence of control strategies on the effriciency factors of space heating and its distribution system. An adaptive control is developed and applied to two types of heating curves (linear and non-linear) for a low-energy building equipped with renewable energy sources. The building is modelled with a hybrid approach (law driven + data driven model). The design of the floor heating is calibrated and validated by assessing the uncertainty bands for low temperatures and mass flow rate. advantages and disavantages of linear and non-linear heating curves are highlighted to illustrate their impact on space heating thermodynamic behaviour and on the efficiency factors of the space heating system.

    Practical application: The study reveals that applying commercial building energy simulation software  is worthwhile to determine reliable performance predictions. Oversimplified building models, in particular when considering building thermal mass, are not capable of simulating the thermodynamic response of a building subjected to different control strategies. The application of different heating cuirves (linear and non-linear) to massless building models leaves the amount of mass flow rate delivered to the space heating unchanged when the building is subjected to sharp variations of the outdoor temperature.

  • 271.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hybrid heating system for open-space office/laboratory2015In: Energy, Science and Technology 2015: Book of Abstracts. The energy conference for scientists and researchers / [ed] Karlsruher Institut für Technologie (KIT), Karlsruher, Germany: Karlsruhe, KIT , 2015, Vol. 1, p. 315-315Conference paper (Refereed)
    Abstract [en]

    Open-space office/laboratory are quite common in Scandinavia and they are usually designed for multipurposework. There are office area where is possible to work standing up and in the same time to work at the desk. Forthis purpose a hybrid heating system made by electric convectors and panel radiators is investigated. Two stepresponse tests of the hybrid heating system are performed at the laboratory of Umeå University. The first test isexecuted during the week, disturbances from heat sources degrading the quality of the results. The second test isperformed during week-end. The error analysis shows a maximum discrepancies of +0.6 °C between measuredand simulated data. However, a thermal time constant of the room can be deducted and use it for controlling purposes.

  • 272.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Transient model of a panel radiator2015In: Energy, Science and Technology 2015: Book of Abstracts. The energy conference for scientists and researchers / [ed] Karlsruher Institut für Technologie (KIT), Karlsruher, Germany: Karlsruher Institut für Technologie (KIT) , 2015, Vol. 1, p. 321-321Conference paper (Refereed)
    Abstract [en]

    This paper shows a detailed transient model of a panel radiator considered as a system of multiple storageelements. The experiment records the temperature surface of the panel in the process of heating up. Thequalitative results of the experiment suggest the more appropriate technique for modelling this technology. The transient model performs the modelling with horizontal thermal capacitances connected in series. This modelcalculates the temperature of exhaust flow, heat emission towards indoor environment, temperature gradient onpanel surface, dead and balancing time identified numerically on the chart.

  • 273.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Transient model of a panel radiator2015In: Proceedings of BS2015: 14th Conference of International Building Performance Simulation Association, Hyderabad, India, Dec. 7-9, 2015, India, Hyderabad: International Building Performance Simulation Association (IBPSA), 2015, , p. 2749-2756p. 2749-2756Conference paper (Refereed)
    Abstract [en]

    This paper shows a transient model of a hydronic panel radiator modelled as a system of multiple storage elements. The experiment´s results suggest the more suitable technique for modelling this technology. The panel radiator is modelled numerically with eight thermal capacitance connected in series by keeping a memory of the heat injected in the thermal unit. The comparison of the performance among lumped steadystate models and transient model, in terms of heat emission and temperature of exhaust flow, shows the potential of the latter approach. To conclude, (1) the transient phase is essential for modelling stocky panels, and (2) this type of modelling has to be addressed for evaluating the performance of low energy buildings.

  • 274.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Vuolle, Mika
    EQUA simualtion.
    Östin, Ronny
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Practical support for evaluating efficiency factors of a space heating system in cold climates: modelling and simulation of hydronic panel radiator with different location of connection pipes2017In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 10, no 5, p. 1253-1267Article in journal (Refereed)
    Abstract [en]

    Plenty of technical norms, included in the EPBD umbrella, assess the performance of buildings or its sub-systems in terms of efficiency. In particular, EN 15316 and its sub-sections, determine the system energy requirements and the system efficiencies of space heating system. This paper focuses on the estimation of efficiencies for emission of hydronic radiators. The assessment of efficiencies for emission occurs by evaluating the amount of heat emitted  from the heat emitter and the extra thermal losses towards building envelope. The heat emitted from radiators varies during the heating up/cooling down phases. A factor that influences the heat emitted during these phases is the location of connection pipes of the radiator. Connection pipes can be located on opposite side or at the same side of the radiator. To better estimate the heat emitted from radiators a transient model with multiple storage elements is used in a building simulation model. Sensitivity analysis encompasses all  the possible variations on extra thermal losses due to the building location in different climates, the heaviness of active thermal mass and the type of radiator local control. The final outcome of this paper is a practical support where the designer can easily assess the efficiencies for emission of hydronic radiators  for Swedish buildings. As main result, (i) the efficiency for control of space heating system is higher in Northern climates than in Southern climates, (ii) heavy active thermal masses allow higher efficiencies for emission than light active thermal masses, (iii) connection pipes located on the same side of the radiator enable higher efficiencies for emission than pipes located on opposite side.

  • 275.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Östin, Ronny
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Predictions' robustness of one-dimensional model of hydronic floor heating: novel validation methodology using a thermostatic booth simulator and uncertainty analysis2018In: Journal of Building Physics, ISSN 1744-2591, E-ISSN 1744-2583, Vol. 41, no 5, p. 418-444Article in journal (Refereed)
    Abstract [en]

    Hydronic floor heating models provide predictions in estimating heat transfer rates and floor surface temperature. Information on the model performance and range of validity of its results are often lacking in literature. Researchers have to know the accuracy and robustness of the model outcomes for performing energy and climate comfort calculations. This article proposes a novel validation methodology based on the uncertainty analysis of input data/parameters of one-dimensional model of hydronic floor heating tested in a thermostatic booth simulator and compared with experimental measurements. The main results are: (1) prediction accuracy between 0.4% and 2.9% for Tf and between 0.7% and 7.8% for qup when the serpentine has tube spacing (p) of 0.30 m, (2) prediction accuracy between 0.5% and 1.4% for Tf and between 8.7% and 12.9% for qup with p = 0.15m and (3) Tfld mostly affects predictions with oscillations between 6.2% and 2.2% for qup. This model provides robust and reliable predictions exclusively for qup when p = 0.30m.

  • 276.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Östin, Ronny
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Paradoxes in understanding the Efficiency Factors of Space Heating2019In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 12, no 3, p. 777-786Article in journal (Refereed)
    Abstract [en]

    Efficiency factors are here defined as the thermal energy performance indicators of the space heating. Until recently, the efficiency factors were assumed as one value for space heating located in any climate. This study addresses the problem of how the outdoor climate affects the efficiency factors of a space heating equipped with 1D model of hydronic floor heating. The findings show how the efficiency factors, computed with two numerical methods, are correlated with the solar radiation. This study highlights the paradoxes in understanding the results of efficiency factors analysis. This work suggests how to interpret and use the efficiency factors as a benchmark performance indicator.

  • 277.
    Bretting, Viktor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bärverk i passivhus: Utformning och dimensionering av en limträ stomme till en passivhus skola2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 278.
    Brostrom, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Branca, C.
    Di Blasi, C.
    Influence of torrefaction on the devolatilization and oxidation kinetics of wood2012In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 96, p. 100-109Article in journal (Refereed)
    Abstract [en]

    Devolatilization and oxidation kinetics of torrefied wood have been studied by evaluating thermogravimetric curves measured in nitrogen and air at various heating rates. Samples consist of Norway spruce wood chips torrefied at several process temperatures and residence times. Data about untreated wood have also been obtained for comparison. Measured curves are well predicted by means of a five-reaction mechanism, consisting of three devolatilization reactions for the pseudo-components hemicellulose. cellulose and lignin and, in air, of two additional reactions for char devolatilization and combustion. The torrefaction pre-treatment only requires model modifications in the amounts of volatiles generated from the decomposition of pseudo-components, indicating that only their relative percentages and not their reactivities are modified. On the other hand, a slightly different thermal stability is found for the char generated from torrefied wood, which results in higher activation energy and lower reaction order for the oxidation step. Hence torrefaction conditions can affect the subsequent conversion characteristics of the char product. (C) 2012 Elsevier B.V. All rights reserved.

  • 279.
    Broström, Marcus
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Utveckling och utvärdering av mätteknik och additiv för alkalikomponenter i termiska energiomvandlingsprocesser2006Report (Other (popular science, discussion, etc.))
  • 280.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Aspects of alkali chloride chemistry on deposit formation and high temperature corrosion in biomass and waste fired boilers2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Combustion of biomass and waste has several environmental, economical and political advantages over the use of fossil fuels for the generation of heat and electricity. However, these fuels often have a significantly different composition and the combustion is therefore associated with additional operational problems. A high content of chlorine and alkali metals (potassium and sodium) often causes problems with deposit formation and high temperature corrosion. Some different aspects of these issues are addressed in this thesis.

    The overall objective of this thesis was to study and highlight different means by which operational problems related to alkali chlorides can be overcome, reduced or prevented.

    The most important results of this thesis are: (1) A full description of the in-situ alkali chloride monitor, its operational principles, the calibration procedure, and an example of a full-scale application was made public in a scientific publication. (2) Efficient sulfation of gaseous alkali chlorides in a full-scale boiler was achieved by injecting ammonium sulfate in a water solution into the hot flue gas. (3) Reduced deposit growth and corrosion rates were achieved by lowering the alkali chloride concentration in the flue gas by sulfation. (4) Evidence of decreased deposit growth and chlorine content in deposits during peat co-combustion. (5) Results are presented from high temperature corrosion tests with different superheater steels in two different combustion environments. (6) Controlled KCl and NaCl condensation under simulated combustion conditions resulted in deposits which consisted of mostly pure phases, in contrast to the solid solution that would be expected under the prevailing conditions at chemical equilibrium.

  • 281.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effects of alkali chlorides in biomass and waste-fired boilers2009Licentiate thesis, comprehensive summary (Other academic)
  • 282.
    Broström, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Andersson, Christer
    Axner, Ove
    Nordin, Anders
    IACM - In situ alkali chloride monitor2004In: 2nd World Conference for Energy, Industry and Climate Protection, Rome, Italy, 2004Conference paper (Other academic)
  • 283.
    Broström, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Enestam, Sonja
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Mäkelä, Kari
    Condensation in the KCl–NaCl system2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 105, p. 142-148Article in journal (Refereed)
    Abstract [en]

    Condensation of gaseous KCl and NaCl is known to participate in deposit formation and high temperature corrosion processes in heat and power plants. Little is known about interaction between the two salts, which is of interest for the overall understanding of deposit and corrosion problems. Within this study, condensation at different material surface temperatures and salt mixtures was investigated.

    Salt vapors were prepared by temperature controlled evaporation. A cooled condensation probe with a temperature gradient was inserted in the hot gas. After exposure, the probe surface was visually inspected and analyzed with SEM/EDS and XRD for elemental and phase composition. TGA/DTA was used to provide complementary information on vaporization and sintering.

    The results indicated that a mixture of KCl and NaCl probably condenses as separate phases at concentrations and temperatures below the melting points of the salts. Condensation was possibly followed by a secondary sintering process. It was verified by TGA/DTA that a mixture of solid KCl and NaCl particles sinters and melts rapidly at temperatures above the melting temperature of a corresponding solution. It was also seen that sintering took place at lower temperatures with slow solid-gas interactions, possibly with the formation of solid solutions.

  • 284.
    Broström, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ash fractionation and slag formation during entrained flow biomass gasification2018Conference paper (Other academic)
  • 285.
    Broström, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Kassman, Håkan
    Vattenfall Power Consultant AB, Box 1046, SE-611 29 Nyköping, Sweden.
    Helgesson, Anna
    Vattenfall Research and Development AB, SE-814 26 Älvkarleby, Sweden.
    Berg, Magnus
    Vattenfall Research and Development AB, SE-814 26 Älvkarleby, Sweden.
    Andersson, Christer
    Vattenfall Research and Development AB, SE-814 26 Älvkarleby, Sweden.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Sulfation of corrosive alkali chlorides by ammonium sulfate in a biomass fired CFB boiler2007In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 88, no 11-12, p. 1171-1177Article in journal (Refereed)
    Abstract [en]

    Biomass and waste derived fuels contain relatively high amounts of alkali and chlorine, but contain very little sulfur. Combustion of such fuels can result in increased deposit formation and superheater corrosion. These problems can be reduced by using a sulfur containing additive, such as ammonium sulfate, which reacts with the alkali chlorides and forms less corrosive sulfates. Ammonium sulfate injection together with a so-called in situ alkali chloride monitor (IACM) is patented and known as "ChlorOut". IACM measures the concentrations of alkali chlorides (mainly KCl in biomass combustion) at superheater temperatures. Tests with and without spraying ammonium sulfate into the flue gases have been performed in a 96MW(th)/25MW(e) circulating fluidized bed (CFB) boiler. The boiler was fired mainly with bark and a chlorine containing waste. KCl concentration was reduced from more than 15 ppm to approximately 2 ppm. during injection of ammonium sulfate. Corrosion probe measurements indicated that both deposit formation and material loss due to corrosion were decreased using the additive. Analysis of the deposits showed significantly higher concentration of sulfur and almost no chlorine in the case with ammonium sulfate. Results from impactor measurements supported that KCl was sulfated to potassium sulfate by the additive. (C) 2007 Elsevier B.V. All rights reserved.

  • 286.
    Broström, Markus
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kassman, Håkan
    Helgesson, Anna
    Berg, Magnus
    Andersson, Christer
    Backman, Rainer
    Nordin, Anders
    Sulphation of Corrosive Alkali Chlorides by Ammonium Sulphate in a Biomass Fired CFB Boiler2006In: Impacts of Fuel Quality on Power Production, Snowbird, Utah, USA, 2006Conference paper (Other academic)
  • 287.
    Brunberg, Marike
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    User optimized design of handheld medical devices -applications and casing2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 288.
    Brundin, Carl
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Alternative energy concepts for Swedish wastewater treatment plants to meet demands of a sustainable society2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report travels through multiple disciplines to seek innovative and sustainable energy solutions for wastewater treatment plants. The first subject is a report about increased global temperatures and an over-exploitation of natural resources that threatens ecosystems worldwide. The situation is urgent where the current trend is a 2°C increase of global temperatures already in 2040. Furthermore, the energy-land nexus becomes increasingly apparent where the world is going from a dependence on easily accessible fossil resources to renewables limited by land allocation. A direction of the required transition is suggested where all actors of the society must contribute to quickly construct a new carbon-neutral resource and energy system. Wastewater treatment is as required today as it is in the future, but it may move towards a more emphasized role where resource management and energy recovery will be increasingly important.

    This report is a master’s thesis in energy engineering with an ambition to provide some clues, with a focus on energy, to how wastewater treatment plants can be successfully integrated within the future society. A background check is conducted in the cross section between science, society, politics and wastewater treatment. Above this, a layer of technological insights is applied, from where accessible energy pathways can be identified and evaluated.

    A not so distant step for wastewater treatment plants would be to absorb surplus renewable electricity and store it in chemical storage mediums, since biogas is already commonly produced and many times also refined to vehicle fuel. Such extra steps could be excellent ways of improving the integration of wastewater treatment plants into the society.

    New and innovative electric grid-connected energy storage technologies are required when large synchronous electric generators are being replaced by ‘smaller’ wind turbines and solar cells which are intermittent (variable) by nature. A transition of the society requires energy storages, balancing of electric grids, waste-resource utilization, energy efficiency measures etcetera… This interdisciplinary approach aims to identify relevant energy technologies for wastewater treatment plants that could represent decisive steps towards sustainability.

  • 289.
    Brus, Elisabet
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Umeå University.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Mechanisms of bed agglomeration during fluidized-bed combustion of biomass fuels2005In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 19, no 3, p. 825-832Article in journal (Refereed)
    Abstract [en]

    The major ash-related problem encountered in fluidized beds is bed agglomeration, which, in the worst case, may result in total defluidization of the bed and unscheduled downtime. Because of the special ash-forming constituents of biomass fuels, several of these fuels have been shown to be especially problematic. Despite the frequent reporting, a precise and quantitative knowledge of the bed agglomeration process during fluidized bed combustion of biomass fuels has not yet been presented. Bed sampling versus operation time was performed in four different biomass-fired full-scale fluidized beds, as well as during controlled fluidized bed agglomeration tests in bench-scale testing of five representative biomass fuels. The bed materials and agglomerates were further analyzed using scanning electron microscopy, coupled with energy-dispersive spectroscopy SEM/EDS, to determine the characteristics of the formed bed particle layers. For typical wood fuels, coating-induced agglomeration with subsequent attack reaction and diffusion by calcium into the quartz was identified to be the dominating bed agglomeration mechanism. Low-melting calcium-based silicates (including minor amounts of, for example, potassium) were formed with subsequent viscous-flow sintering and agglomeration. For high-alkali-containing biomass fuels, direct attack of the quartz bed particle by potassium compounds in a gas or aerosol phase formed a layer of low-melting potassium silicate. Thus, formation and subsequent viscous-flow sintering and agglomeration seemed to be the dominating agglomeration mechanism for these fuels.

  • 290.
    Brus, Elisabet
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Hedman, Henry
    Energy Technology Centre, Piteå, Sweden.
    Eklund, Anders
    Bed agglomeration characteristics of biomass fuels using blast-furnace slag as bed material2004In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 18, no 4, p. 1187-1193Article in journal (Refereed)
    Abstract [en]

    Agglomeration of bed material may cause severe operating problems during fluidized bed combustion. The attack or coating layers that are formed on the bed particles during combustion play an important role in the agglomeration process. To reduce bed agglomeration tendencies, alternative bed materials may be used. In this paper, bed agglomeration characteristics during the combustion of biomass fuels using a relatively new bed material (iron blast-furnace slag) as well as ordinary quartz sand were determined. Controlled agglomeration tests lasting 40 h, using five representative biomass fuels (bark, olive residue, peat, straw, and reed canary grass) were conducted in a bench-scale fluidized bed. The bed materials and agglomerates were analyzed using SEM/EDS and X-ray diffraction. Chemical equilibrium calculations were performed to interpret the experimental findings. The results showed that blast-furnace slag had a lower tendency to agglomerate than quartz sand for most of the fuels. The quartz particles showed an inner attack layer more often than did the blast-furnace slag. The blast-furnace slag had a lower tendency to react with elements from the fuel. The outer coating layer had similar characteristics and thickness for both bed materials when the same fuel was combusted. However, the inner attack layer thickness was larger for quartz particles. SEM/EDS analyses of the agglomerates showed that the inner Ca-K-silicate-rich attack layer was responsible for the agglomeration of quartz sand. The composition of blast-furnace slag agglomerate was similar to the outer coating layer. Chemical equilibrium calculations showed that the original composition of the blast-furnace slag was close to the equilibrium composition, and hence there was no major driving force for reactions between that bed material and K and Ca from the fuel. The homogeneous silica-rich attack layer (with a low melting temperature) was not formed to the same extent for blast-furnace slag, thus explaining the lower bed agglomeration tendency.

  • 291.
    Bränberg, Agneta
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hur startar man ett helt nätbaserat utbildningsprogram?: IngOnline som ett exempel på COI för blended learning2009In: Undervisning på tvären: student och lärarerfarenheter : den nionde universitetspedagogiska konferensen 25-26 februari 2009 : konferensrapport / [ed] Erik Lindenius, Umeå, 2009, p. i-xConference paper (Other academic)
    Abstract [sv]

    Denna artikel kommer att beskriva hur vi, en grupp på åtta personer från åtta olika högskolor, jobbat tillsammans för att utveckla och starta ett helt nätbaserat högskoleingenjörsprogram i datateknik/elektroteknik. Arbetsmetoden som vi använt har (sett i en backspegel) vilat tungt på att vi kunnat träffas rent fysiskt för att få en social interaktion och däremellan kunnat ha olika typer av täta kontakter av mer virtuell natur där tekniken har varit till stor hjälp. Man kan uttrycka det som att vi använt så kallad Blended Learning. Formen för samverkansgruppen skulle man kunna beskriva som ett Community of Inquiry, dvs en grupp människor som samverkar för att bygga kunskap.

    Artikeln kommer att beskriva arbetsmetoden, hur vår grupp såg ut, vad vi har fått för erfarenheter av att jobba på detta vis, hur programmet blev och vad man kan ta med sig om man tänker starta ett nytt program på samma sätt som vi gjort.

  • 292.
    Bränberg, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Ulf
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Attityder och förmåga! Utbildning också för den högra hjärnhalvan: Erfarenheter från en inledande kurs på ett ingenjörsprogram2007In: Utsikter, insikter, avsikter: universitetspedagogisk konferens i Umeå 27 – 28 februari 2007 / [ed] Mohammad Fazlhashemi och Thomas Fritz, Umeå: Umeå Universitet, Universitetspedagogiskt centrum , 2007, p. 41-54Conference paper (Other academic)
    Abstract [sv]

    Undervisningssituationen är ett samspel mellan lärare och student. Studentens framgång i studierna är i hög grad beroende av hur denna relation etableras och hur den utvecklas under studietiden. Inte minst viktigt är att vara uppmärksam på hur relationen etableras och där är lärarens attityd till studenten av betydelse. Att i någon mån släppa de ämnesstyrande kraven och redan tidigt i utbildningen skapa situationer där kreativiteten och de yrkesmässiga målen för utbildningen får dominera ökar studenternas vilja att arbeta aktivt i och med sin utbildning. Det ger utrymme för lärstilar som inte enbart bygger på teoretiskt kunskapsinhämtande och framförallt får vi som lärare en mycket roligare, mer utvecklande och mer spännande arbetssituation. Med denna artikel vill vi visa på möjligheter att med framgång och mycket tidigt i utbildningen arbeta projektorienterat och yrkesnära. Rapporten redovisar ett försök att mycket tidigt i utbildningen arbeta med ingenjörsmässiga frågeställningar utifrån studenternas erfarenheter och värderingar.

  • 293.
    Bränberg, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Ulf
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Forskningsanknytning av grundutbildning: en praktisk analysmetod2015In: 5:e Utvecklingskonferensen för ingenjörsutbildningar: Proceedings, Uppsala: Uppsala universitet, 2015, p. 51-55Conference paper (Other academic)
    Abstract [sv]

    Forskningsanknytning av grundutbildning kan och ska inte enbart vara fokuserad på att våra lärare är forskare. Det är så mycket mer kopplat till den. Som så många gånger när världen ser komplex ut är det lätt att man förenklar den alltför mycket. I denna artikel försöker vi vidga begreppen. Vi presenterar en analysmodell i form av ett fyrfältsdiagram, som kan byggas ut med en progressionsskala. Modellen som presenteras är ett verktyg som kan fungera både för analys av och som utgångspunkt för diskussioner om forskningsanknytning av ingenjörsutbildningar.

  • 294.
    Bränberg, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Ulf
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kursdesign med utgångspunkt i utveckling av kreativitet, kritiskt förhållningssätt och initiativförmåga2011In: 3e Utvecklingskonferensen för Sveriges ingenjörsutbildningar. 30 november-1 december 2011, 2011, p. 112-116Conference paper (Other academic)
    Abstract [sv]

    Kursen Analog elektronik 15hp är den första renodlade ämneskurs som studenterna på högskoleingenjörsprogrammet i Elektronik och datorteknik möter och den ges under senare delen av höstterminen i första årskursen. Kursen är central på programmet dels ämnesmässigt men framförallt genom önskemålet att etablera ingenjörsmässiga arbetsformer och ett ingenjörsmässigt förhållningssätt i kommande kurser på programmet. Tre aspekter bildar bas för kursens målbeskrivning

     -Kunskapsbasen definierad av klassisk analogiteknik och elementära elektroniska system

    -Färdighetsmålen med fokus på konstruktion, experiment, simulering och analys

    -Formerande av en attityd till lärande där kreativitet, lagarbete och kritiskt förhållningssätt står i centrum

    I presentationen diskuteras hur arbetsmetodik, kursinnehåll och examination kan utformas i syfte att stödja samtliga tre måldimensioner och hur motivation, personligt ansvarstagande och professionellt förhållningssätt kan utvecklas genom en medveten utformning av läraktiviteter.

  • 295. Bränberg, Agneta
    et al.
    Holmgren, Ulf
    Chrsitensen, Bendt
    Eklund, Robert
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ramstedt, Madeleine
    Undervisningens forskningsanknytning2014Conference paper (Refereed)
  • 296.
    Bränberg, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Ulf
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gulliksson, Håkan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Didaktik för ingenjörslärare2013In: 4:e Utvecklingskonferensen för Sveriges Ingenjörsutbildningar, 2013, p. 9-11Conference paper (Other academic)
    Abstract [sv]

    Didaktik är vetenskapen om alla faktorer sompåverkar undervisningen och dess innehåll, och sätter fokus pålärande och hur lärande organiseras. Didaktik berör alltså vadläraren skall tänka på vid undervisning, dess mål och medel samtsambandet dem emellan. Ämnesdidaktiken fokuserar på vilkavillkor som är av betydelse för lärandet av ett specifikt ämne påolika nivåer, exempelvis matematikdidaktik eller språkdidaktik.Målet för professionsutbildningar (exempelvisingenjörsutbildningarna) skiljer sig från ämnesorienteradeutbildningar genom att fokus ligger på yrkesrollen, vad denexaminerade studenten ÄR, vad den GÖR och kanske i tredjehand vad han eller hon KAN. Detta påverkar hur vi somingenjörslärare hanterar de didaktiska frågorna VARFÖR, HURoch VAD? Rundabordsdiskussionen berör frågeställningar kringutvecklandet av en ingenjörsdidaktik samt hinder ochmöjligheter för denna didaktik att få ett större genomslag i dendagliga didaktiska praktiken. Diskussionen tar avstamp i ennyutkommen bok ”Didaktik för ingenjörslärare” [1].

  • 297.
    Bränberg, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Ulf
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gulliksson, Håkan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Didaktik för ingenjörslärare: konsten och glädjen med att utbilda ingenjörer2013 (ed. 1)Book (Other academic)
  • 298.
    Bränberg, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Winka, Katarina
    Umeå University, Faculty of Arts, Centre for Teaching and Learning (UPC).
    Tänk vad vi är bra: pedagogiska portföljer ger ringar på vattnet2013In: Reformation, revolution, evolution: universitetslärandet ur ett tidsperspektiv / [ed] Erik Lindenius, Umeå: Umeå universitet , 2013, p. 123-138Conference paper (Other academic)
  • 299.
    Bräne, Arvid
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    User Experience Design for Children: Developing and Testing a UX Framework2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Designing good digital experiences for children can be difficult; designers have to consider children's cognitive and motor skill limitations, understand their target audience, create something entertaining and educational, comply with national and international jurisdiction, and at the same time appeal to parents. We set out to create a general framework which designers and developers can use as a foundation and testing ground for their digital products in the field of user experience.

    The methods used during the thesis include interviews, literature studies, user testing, case studies, personas, prototyping, and more. The results created are primarily user experience guidelines packaged in a Theoretical Framework, user testing conclusions, along with suggestions on improving the current Lego Star Wars: Force Builders application, a few in the form of prototypes.

  • 300.
    Brännback, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    FTTX-Analysverktyg anpassat för Telias nät2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A tool for analyzing the status of Fiber to the X (FTTX) customers in Telia’s network has been programmed in the Python programming language. The system consists of a module divided structure where analysis functions of similar types are bundled into module files. The system is designed to be easily further developed by adding more analysis modules in future projects. To perform an analysis on a specific customer, the system retrieves technical data parameters from the switch which the customer is connected to, and compares these parameters against predetermined values to find deviations. Simple Network Management Protocol (SNMP) and Telnet are the primary protocols used to retrieve data. Hypertext Transfer Protocol (HTTP) is used to transfer data as system input and output. The result of an analysis is sent as Extensible Markup Language (XML) back to the server that originally requested the start of an analysis. The XML reply contains technical data parameters describing the customer’s connection status and an analytical response based on these technical parameters. The amount of data presented in the XML response varies slightly depending on the type of switch the customer is connected to. Switches of older hardware types generally presents less customer port data compared to more modern switches. Less customer port data leads to poor detail in the analytical response, and therefore, this analysis tool is better suited to the modern switches found in Telia's network.

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