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  • 151.
    Eriksson, Tommy
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Övertoner i kemisk industri: Harmonics in chemical industry2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Disturbance in the power grids is a problem that is spread worldwide and have negative effect

    on the power quality. It also gives unwanted costs for consumers as well as producers of

    electrical power. The main reason to problems with the power quality is the increasing use of

    non-linear loads connected to the power grid. The term “Power quality” is used to define the

    quality present in the power system. The typical disturbances in the power system are

    harmonics, change in voltage and transients. By measuring and analysing a result can be

    given to see what arrangements might be necessary to increase the power quality.

    Akzo Nobel Pulp & Performance Chemicals AB is an industry who mainly

    produces bleaching chemicals. In the process a large amount of electrical energy is needed

    and problems in the power quality have occurred multiple times. The main issue is the

    generation of harmonics which is spread to the connected power grid. They want to minimize

    the spread of harmonics to help increasing the power quality in the internal system and the

    external grid. The plant is connected to 70 kV incoming voltage which supplies the loads via

    the switchgear. The loads mainly consist of rectifiers and variable frequency drives.

    The reason this study has been conducted is to gather information and measurements as an

    initial start for a larger investigation for larger study for an installation of a harmonic filter.

    This report will show measurements of the harmonic’s being presence, filtering methods

    available and some proposals for the larger study and how to minimize the harmonic

    generation.

    To get an understanding on harmonics studies has been done on theories on the topic such as

    Power quality, Fourier analysis and filtering methods being available. Some studies on the

    type of non-linear loads connected in the plant such as rectifiers and variable frequency drives

    has been done as well. Measurements in the main switchgear of the three supplying phases in

    the point of common coupling have been done.

    The results show that the level of harmonics exceeds the given limit at many times. And the

    given limit is only fulfilled with reduced use of power by the plant. The main harmonic that

    contributes in exceeding the given limit is the 7:th harmonic, which makes sense with the

    theory in harmonic generation given by rectifiers and variable frequency drives. The 5:th

    harmonic should be more present based on the same theories, but they are not. This is

    considered to be because of a phase shift between the loads connected. The even harmonics is

    seen in the system as well which indicates a non-symmetrical case for the system. The nonsymmetrical

    case are within acceptable limits. Filtering are necessary to keep the level of

    harmonics under the limit. A planning in locating the loads should also be considered with the

    harmonics in mind for future changes in the system.

  • 152.
    Eriksson, Torbjörn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konfigurerbar och portabel simulatorhårdvara: Framtagning av koncept2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Based in Umeå, Sweden, Oryx Simulations is looking to explore the possibilities to produce a concept of a set of modularized desktop simulation hardware. Based on a common platform, the idea is to increase ease of setting up the hardware according to chosen simulation.

    The project is managed with a subset of the agile development method, modified for product concept development.

    The final concept is a modularized hardware platform that is relatively easy to configure to suit the chosen simulation. 

  • 153.
    Eskills, Jonathan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Betydelsen av en byggnads planlösning vid energieffektivisering: Enligt simulering i IDA ICE2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The residence and service sector stand for 40 % of the total energy use in Sweden. 90 % of that energy is used for households and facilities, which means that its energy use is only surpassed by that of the industry

    An appropriate solution for a national reduction in use of energy is therefore to streamline the energy efficiency for existing and planned buildings.

    The aim for this academic work is to examine how different methods of streamlining energy use is affected by building planning. Two real life buildings are to be compared and analysed. The buildings have identical outer dimensions and construction, and one of them has a comparatively more open building plan.

    Five different streamlining solutions are going to be simulated in the software EQUA IDA ICE; a lowering of the room temperature, an increased efficiency on the heat exchanger in the air handling unit, a decreased U-value (a Swedish building standard in energy transmission) for the windows, a decreased U-value for the roof and lastly a change from a proportional control system to a proportional integrating on the heating and cooling system.

    The results show that:

    A lowering of the room temperature by 2 ˚C, lessens the heating load for the air handling unit by 42,5 % in the building with a more open building plan, whilst the less open building sees a decrease of 35,8 %.

    The effect of an increased efficiency from 0,6 to 0,9 on the heat exchanger in the air handling is unaffected by a buildings planning.

    A lowered U-value for the windows from 1,8 to 1,1 W/m2,K increases the cooling load for the air handling unit by 130 % on the building with the more open planning. And at the same time the building with the less open planning is unaffected by the streamlining.

    A lowered U-value for the roof from 0,09 to 0,05 W/m2,K gives an increased performance on the heating load for both the heating system and air handling unit on the building with the more open planning, compared to that of the less open building.

    If the control system of the heating and cooling systems changes from a proportional integrating to a proportional one, the cooling load for the cooling system increases by 4,1 % on the building with the more open planning, whilst it increases by 17,1 % on the less open building.

    Streamlining the energy use of ventilation, cooling and heating systems has a bigger impact on buildings with a more open planning compared to those with a less open building plan.

    A less open building plan is better affected by the streamlining of the energy transmission trough the construction compared to a more open planning.

  • 154.
    Eskilsson, Gustav
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Tappningsrobot blykaldoverk: Automatisering av provtagning, temperaturmätning och och klabbning för blykaldo.2016Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
  • 155.
    Fagerström, Jonathan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Fine particle emissions and slag formation in fixed-bed biomass combustion: aspects of fuel engineering2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is a consensus worldwide that the share of renewable energy sources should be increased to mitigate climate change. The strive to increase the renewable energy fraction can partly be met by an increased utilization of different biomass feedstocks. Many of the "new" feedstocks puts stress on certain challenges such as air pollution emissions and operation stability of the combustion process. The overall objective was to investigate, evaluate, and explain the effects of fuel design and combustion control - fuel engineering - as primary measures for control of slag formation, deposit formation, and fine particle emissions during biomass combustion in small and medium scale fixed-bed appliances. The work in this thesis can be outlined as having two main focus areas, one more applied regarding fuel engineering measures and one more fundamental regarding the time-resolved release of ash forming elements, with particular focus on potassium.

    The overall conclusion related to the abatement of particle emissions and slag formation, is that the release of fine particle and deposit forming matter can be controlled simultaneously as the slag formation during fixed-bed biomass combustion. The methodology is in this perspective denoted “fuel engineering” and is based on a combined approach including both fuel design and process control measures. The studies on time-resolved potassium release showed that a Macro-TG reactor with single pellet experiments was a valuable tool for studying ash transformation along the fuel conversion. The combination of dedicated release determinations based on accurate mass balance considerations and ICP analysis, with phase composition characterization by XRD, is important for the understanding of potassium release in general and time-resolved data in particular. For wood, the results presented in this work supports the potassium release mechanism from "char-K" but questions the previously suggested release mechanism from decomposition of K-carbonates. For straw, the present data support the idea that the major part of the potassium release is attributed to volatilization of KCl. To further explore the detailed mechanisms, the novel approach developed and applied in this work should be complemented with other experimental and analytical techniques.

    The research in this thesis has explored some of the challenges related to the combined phenomena of fuel conversion and ash transformation during thermochemical conversion of biomass, and has contributed with novel methods and approaches that have gained new knowledge to be used for the development of more effective bioenergy systems.

  • 156.
    Fahlén, Albin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Småskalig vattenkraft vid Olofsfors bruksmuseum: Med faunapassage2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Sweden there are 1894 small-scale hydropower plants in operation, which together generate 4.3 TWh of electricity per year according to Swedish hydropower compound (SVKF, 2011). This corresponds to the annual consumption of about 860,000 Swedish households (based on an annual consumption of 5000 kWh). In the mid-1950s there were around 4000 small-scale hydropower plants in operation in Sweden before cheap fossil fuels and uranium competed with them, in the current situation only 1,894 of these are in use. If slumbering small hydropower plants once again would be taken into use and some new ones are built, we would be able to extract about 7 TWh of renewable electricity from these annually in Sweden, representing about 1.4 million households.

    The thesis intends to calculate and construct a hydroelectric power plant at the existing dam in Olofsfors and give suggestions on how the power station should run during the time that fish migration is greatest in Leduån.

    The turbine and generator to the station in Leduån at Olofsfors is designed by the height of the fall and the water flow through the dam. The turbine selected for the station is a CK-1000RM turbine with a 4-pole 250 kW generator from Cargo & power turbine Sweden AB, which is expected to deliver 1.2 GWh per year. To facilitate the fish migration from the birth- and breeding place to the sea, the plan is to put down a 1.5 m high plate at the intake to prevent the surface water to flow through the turbine. Then you reduce the flow through the turbine to increase the flow of water through the fish ladder. This is done because the fish during their migration often swims at depth of 1 m and the fish also follows the main stream of the water. Fish migration is solely controlled by the temperature in the water. This means that you can predict when the migration takes place and perform the actions to reduce water flow through the turbine and prevent surface water passing through the turbine with the plate.

  • 157.
    Falk, Joel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Grimm, Alejandro
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Difference in phosphate speciation between sewage sludge and biomass ash from fluidized bed combustion2018In: 27th International Conference of Impacts of Fuel Quality on Power Production and the Environment, September 23–28 September, 2018, Lake Louise, Canada, 2018Conference paper (Refereed)
    Abstract [en]

    The role of phosphorus in biomass combustion is a topic that has become increasingly relevantin recent years. Due to the demand for new sources of renewable energy and recovery of phosphorus from waste streams such as sewage sludge, research into the behavior of phosphorus during combustion is necessary for a continued development. This study aims to investigate potential differences in phosphate behavior during co-combustion of sewage sludge compared to other phosphorus-rich biomass or additives. The investigation was carried out in a bench scale bubbling fluidized bed, co-combusting six biomass blends of similar ash composition and combustion conditions but with different phosphorus association (logging residues (LR) or wheat straw (WS) with sewage sludge (SS), dried distiller’s grain (DG), or phosphoric acid (PA)). After combustion, bed ash samples, fly ash deposits and cyclone ash were collected and analyzed for elemental composition (SEM-EDS) and phase composition (XRD). Based on the XRD phase analyses, a significant difference in phosphate speciation were foundbetween biomass blends containing SS compare to DG or PA. Only two phosphate phases were identified in the ash from SS blends compared to a large variety of phosphates in ash from DG or PA blends. The difference in speciation could not be explained by a difference in ash fractionation as the elemental composition of the analyzed ash fractions were similar. Rather, the results indicate that the behavior of phosphorus in SS may be different to that in DG or PA.

  • 158.
    Feng, Ruixue
    et al.
    Tsinghua University.
    Zhong, Hongtao
    Tsinghua University.
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Influence of gas expansion on the interaction between spatially periodic shear flow and premixed flame2017Conference paper (Other academic)
  • 159.
    Finell, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energiberäkningar för olika lösningar av VVS-system vid Hjältarnas Hus i Umeå.: Jämförelse av olika systemlösningar för VVS genom simuleringar i IDA ICE.2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 160.
    Fjellstedt, Emelie
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energiåtervinning ur kylluft: Svenska Lantmännens foderfabrik i Holmsund i samarbete med Umia AB2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

     Lantmännen i Holmsund tillverkar pelleterat djurfoder till gris, nöt, ren och höns. På fabriken finns tre stycken presslinjer som pressar råvarorna till pellets. Vid tillverkning av pellets blandas råvarorna med ånga som håller ca 75-78°C. Ångan gör att pelletsen blir varm och fuktig efter tillverkningen. För att pelletsen ska kunna hålla en god kvalité vid transport och förvaring torkas denna med luft i pelletskylar. Varje presslinje har en egen pelletskyl. Kylluften som lämnar pelletskylarna är relativt varm och fuktig. En del av energin som finns i kylluften tas idag tillvara på i ett återvinningssystem som ger värme till fabriken och melassanläggningen. Trots den nuvarande återvinningen är kylluftluftflödet fortfarande varmt när den lämnar byggnaden. En del av målet i arbetet har varit att reda på vilken energi som finns i den utgående kylluften och vilken kvalité denna har. Den andra delen av syftet har varit att utreda hur denna energi kan tas tillvara. Mätningar visar att kylluften från press 1 och 2 håller en medeltemperatur på ca 45°C och ett medel volymflöde på 7,5 m3 /s när den lämnar byggnaden. Från presslinje 3 håller luften en något högre temperatur och volymflödet är ungefär hälften. Möjliga avsättningsområden för energin är fabriksvärmesystemet, melassanläggningen samt tappvarmvatten.

    Ungefärligt energibehov för dessa områden är:

    Melassanläggning 133 MWhFabriksvärme 68 MWhTappvarmvatten 15,6 MWh

    För att dessa områden ska kunna tillgodogöra sig energin som finns i kylluften behöver temperaturerna in i systemen vara högre än vad som finns tillgängligt i kylluften. För detta ändamål föreslås att två stycken värmepumpar installeras på fabriken. En värmepump för att värma melassanläggningen och en värmepump som kan förse fabriksvärmesystemet och tappvarmvattenberedning med värme. Det finns ett stort energiöverskott från kylluften kontra avsättningsområdena. Energitillgången från frånluften är dock inte konstant utan styrs efter produktionen i fabriken. Genom att installera en ackumulatortank visar beräkningar att värmepumparna skulle kunna täcka 80 % av energiförbrukningen. Ekonomiska beräkningar visar att Lantmännen i Holmsund kan göra en besparing på 130 000 kr/år om de föreslagna åtgärderna införs. Återbetalningstiden för anläggningen beräknades till 8,1 år.

  • 161.
    Fjellstedt, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energioptimering av tryckluft: Genom värmeåtervinning och driftoptimeringar för industriella tillämpningar på Volvo Trucks i Umeå2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Volvo Trucks in Umeå use large amounts of compressed air and the air compressors at Volvo use large amounts of energy every year. The majority of the energy supplied to the compressors goes to heat losses cooled to the Ume River and groundwater.

    The purpose of this project was to develop a new heat recovery system where a larger part of the compressor heat is used and various suggestions for optimizations on the compressed air system.

    Lack of digital control systems on the compressed air system has led to various operating problems and difficulties in diagnosing them while making optimizations difficult. The absence of logged data led to lack of various critical compressor data that instead had to be estimated with different calculation methods.

    The report resulted in a number of measures that were proposed, such as an investment in a variable speed drive compressor with heat recovery to the district heating system, various operating optimizations and a reworking of the current heat recovery system. The heat recovery systems showed to have great saving potential with a short payback period.

    The heat recovery systems that were developed in the project was to recycle heat from a new air compressor to the return line on the district heating at a station inside the factory and a heat exchange on three current compressors towards a nearby district heating line. It was thus possible to show significant reductions in the amount of purchased district heating and energy costs without affecting other processes.

    An outdated compressed air system showed higher future costs due to increased service costs and a future need for renovations on compressors. This means that Volvo probably would have reduced costs by investing in a new air compressor. 

  • 162.
    Flygare, Kristoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energisimulering av Fortifikationsverkets Kontorsbyggnad 1: Energisimulering och utvärdering av renovering2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this project is to analyze an upcoming renovation of an office building in Boden, owned by Fortifikationsverket. The project makes use of the software IDA Indoor Climate and Energy and Revit to simulate the building as it will function after completed renovation. This way Fortifikationsverket has a reference value to use when evaluating the actual performance of the building.

    The project introduces the reader to Revit as well as to the simulation program IDA ICE and shows how energy consumption may be simulated when one wishes to renovate a building. Drawings, an energy report and measured energy consumption act as the basis for the simulation and where values are not available assumptions are made. The upcoming renovation consists of a new HVAC system and rules set forth by Fortifikationsverket which are to be followed when a building under their regime is renovated. These rules consists of reducing air leakage, lowering room temperature and installing more effective lightning, fans, heat exchangers and air cooling.

    The project finds that the upcoming renovation lowers the yearly energy consumption of the building by approximately 31 %, heating and electricity are included in this energy consumption and are lowered by approximately 29 % and 33 % respectively. The yearly use of heating and electricity is found to be 409 009 kWh and 446 905 kWh respectively.

    Of the various measures taken by the renovation the heat recovery is found to be the most effective. The electricity consumption was lowered most by more effective lightning and fans.

  • 163.
    Forsgren, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    P 1400 Test och Justering2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Komatsu Forest AB har som mål att under framtiden producera 1400 maskiner varje år. För att kunna bemöta den ökade produktionen och säkerställa kvaliteten på produkterna som ska levereras krävs beslutsunderlag på ytor och storlek på alla avdelningar vid KFAB.

    Syftet med projektet var att ta fram beslutsunderlag på storleken på testyta, antal justeringshallar och antal buffertplatser för test och justeringsavdelningen vid 1400-takt. Resultatet kom att visa behovet vid en produktion enbart under dagtid samt ett resultat av behovet vid skiftarbete.

    För att ta fram behovet har två tidsstudier gjorts på de två maskintyperna som KFAB levererar. Tidsstudien utfördes som en klockstudie där resultatet visas i både tårtdiagram samt från balanseringsprogrammet Avix som användes som stapeldiagram. Dessa visar hur balanseringen mellan de olika förarna av maskinerna såg ut. Ett resultat som gynnade projektarbetet. Viktigt att komma ihåg vid en tidsstudie är att ha ett nära sammarbete med den berörda avdelningen. Eftersom det är dessa personer som i framtiden kommer att arbeta efter det tidsstudieresultat som tas fram, samt deras erfarenheter och kundskap i momentet tas med.    

    De slutgiltiga resultaten av projektet sammanställs med 2D-ritning och markering om den plats, som dessa i anslutning till fabriken i Umeå kan rymmas. Positivt med de två framtagna resultaten är att ytorna kommer att rymmas i anslutning till där fabriken är idag och inte kräver flytt till annan plats.

    Rekommendationerna som kommer fram under rapportens gång är att renovera de befintliga justeringshallarna så att tvättning av maskinerna kan utföras i alla justeringshallarna. Vid testytan sätts skyddsstängsel upp som skyddar mot både bilväg och cykelbana, samt utöka varje enskilds testplats något jämfört med idag. De nya buffertytorna ska märkas upp ordentligt på den asfaltsbelagda ytan som rekommenderas.  

  • 164.
    Forsgren, Zebastian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nykonstruktion av krympbänk2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Cranab is a company that specializes and manufactures cranes and grippers for forwarders, harvesters and trucks. During the manufacturing process, a shrink fit bench is used to assemble two parts together. The part that is being assembled is called a pillar. The pillar has two big components, a pipe and a splined part. These two parts is being assembled in the shrink fit bench. The current shrink fit bench is using a propane torch to heat the pipe so the splined part can be inserted. After the pipe has cooled down the part is assembled with a shrink fit. The purpose of this thesis is to draw and deliver a new concept of a new and improved shrink fit bench. The method used is to study the current shrink fit bench and draw a new one using Autodesk Inventor. The new and improved shrink fit bench is using an induction heater instead of a propane torch. The result of this work is a shrink fit bench with drawings and associated calculations and explanations of induction and comparisons on different types of induction coils.

  • 165.
    Fotios, Kasolis
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Analysis of fictitious domain approximations of hard scatterers2015In: SIAM Journal on Numerical Analysis, ISSN 0036-1429, E-ISSN 1095-7170, Vol. 53, no 5, p. 2347-2362Article in journal (Refereed)
    Abstract [en]

    Consider the Helmholtz equation del center dot alpha del p+k(2 alpha)p = 0 in a domain that contains a so-called hard scatterer. The scatterer is represented by the value alpha = epsilon, for 0 < epsilon << 1, whereas alpha = 1 whenever the scatterer is absent. This scatterer model is often used for the purpose of design optimization and constitutes a fictitious domain approximation of a body characterized by homogeneous Neumann conditions on its boundary. However, such an approximation results in spurious resonances inside the scatterer at certain frequencies and causes, after discretization, ill-conditioned system matrices. Here, we present a stabilization strategy that removes these resonances. Furthermore, we prove that, in the limit epsilon -> 0, the stabilized problem provides linearly convergent approximations of the solution to the problem with an exactly modeled scatterer. Numerical experiments indicate that a finite element approximation of the stabilized problem is free from internal resonances, and they also suggest that the convergence rate is indeed linear with respect to epsilon.

  • 166.
    Foutou, Smithuseen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konceptförslag på maskin för simulering av tuggprocess2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When you lose one or more teeth or have large toothgap, dentures or implants may be an option in many cases. Many specialized clinics today are increasingly practicing these operations that  make people who lose their teeth have new teeth while maintaining good oral hygiene. The implants is held to place by four screws but the new attachment vill onlys have two screws.

    The new version machine vill be constructed for simulation of chew process. It vill be more productive, easier to move and specially it vill be equiped with a USB so that a computer will connected when needed. The machine vill be constructed with a programmable logic controller (PLC) an industrial digital computer which has been ruggedised and adapted for the control of manufacturing processes or any activity that requires high reliability control and ease of programming and process fault diagnosis. In addition to the PLC the machine will have the cylinder, a sound damper and also the pressure transmitter.

    The new machine will have a better way to control the pressure. The design proposal meet the requirements of the customer and above all to fulfill the purpoae for which it will be constructed.

  • 167.
    Fredriksson, Petter
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Beräkning av värmeförluster och energieffektivisering av elbussar2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The ”civilized” world is in need of fossil fuel in order to function. Hybricon AB is a company in Umeå that is developing a technology that hopefully can reduce parts of this need. They are currently testing their two electrical busses (with Hybrid backup) in city traffic on the roads of Umeå in cooperation with the county of Umeå.

                                   

    The busses are originally diesel-busses, but the diesel motor has been replaced with two electrical hub-motors with a power of 145 kW each that are powered by batteries.

    The batteries are charged at the end station after each route. In case the batteries should run low on capacity during driving, they can be recharged by the so called genset. The genset consists of a diesel-engine with a generator.

     

    A general problem with electrical vehicles is their lack of waste heat for compartmental heating, due to higher efficiency of the electrical engine and the fact that the energy conversion doesn’t involve combustion. An ordinary diesel-buss can use the waste heat from the engine for compartmental heating, but even that is not enough to satisfy the need of heat to keep the bus warm in for example northern Sweden, where the climate is very cold during winter.

     

    The purpose of this thesis is to help Hybricon investigate how big the heat losses are for the electrical busses and thereby calculate the maximum need of heating power, and also investigate what different energy efficient actions can contribute to lowering the need of heating power. The goal for Hybricon is to be independent of fossil fuels for the heating of their busses, after future energy efficient actions.

     

    The power for heating in the bus at its original manufactured state is between 40-50 kW when the doors are closed and between 100-500 kW depending on the number of doors open simultaneously (one, two or three).

     

    Through energy efficient actions in the climate shell, the maximum heating power for the bus can be lowered by 22,4 % when the doors are closed and about 3,5 % when doors are open.

    It is shown that the biggest heat loss occurs when one or more doors are open. Many energy efficient actions must be made and especially the heat loss through the doors must be lowered significantly, if the busses are to be heated in an energy efficient way and without need of fossil fuels.

  • 168.
    García López, Natxo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Biomass utilization for energy purposes in Kenya: Fuel characteristics and thermochemical properties2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    About forty percent of the world´s population, mostly inhabitants of countries with developing economies, rely on the traditional usage of biomass for energy purposes. The major negative consequences are environmental and health effects. Additionally, the most remarkable social consequence is rural poverty which is directly linked to lack of access to electricity. This places the questions related to biomass utilization for energy production at the core of global welfare.The present work was performed as a part of a larger research project funded by Formas and which involves Swedish and Kenyan partners. The aim of this study was to gather basic knowledge about the characteristics of relevant biomass from sub-Saharan Africa, more specifically from Kenya. Eight different types of biomass, including agroforestry trees, agricultural residues and water hyacinth, were evaluated according to fuel characteristics and thermochemical properties. Ultimate and proximate analyses of the collected biomass were carried out, in addition to heating values analyses. Moreover, the biomass was pelletized and a thermogravimetric analysis was performed in a single pellet reactor. Finally, the composition of the residual ashes was determined. The results show that there was a large variation in the fuel characteristics and thermochemical behaviour of the studied agricultural residues and water hyacinth biomass types, whereas agroforestry trees had rather similar properties and thermochemical behaviour when combusted at the same temperature. In addition, results from the ash composition analyses showed large differences among the studied biomass types, which can be used to better predict and solve problems related to the combustion of these biomass types.

  • 169. Gavelin, A
    et al.
    Lindquist, Mats
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Oldenburg, M
    Modelling and simulation of seat-integrated safety belts including studies of pelvis and torso responses in frontal crashes2007In: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 12, no 4, p. 367-379Article in journal (Refereed)
    Abstract [en]

    The aim of the present study is to investigate how the physical properties influence the interaction of the seat back frame and the safety belt. Seat-integrated 3- and 4-point configurations with both non-rigid and rigid seat back frames were compared with common 3-point configurations with anchor points on the car body. The LS-DYNA FE-analysis software was used in order to perform frontal crash simulations with a belted 50th percentile Hybrid III FE-dummy model as occupant. The belt-webbing distribution between the lap and the torso belts via a slip-ring and in combination with a non-rigid seat back frame increases the ride-down efficiency compared to a system with no belt-webbing distribution. No tendencies of pelvis submarining were observed regardless of belt configuration. The dynamic response of the seat back frame has some influence on the ride-down efficiency.

  • 170. Gavelin, A
    et al.
    Lindquist, Mats
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Oldenburg, M
    Numerical studies concerning upper neck and head responses in frontal crashes with seat-integrated safety belts2007In: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 12, no 5, p. 465-479Article in journal (Refereed)
    Abstract [en]

    Mitigation of neck and head injuries is critical in automotive occupant protection. The aim of the present study is to investigate how the physical properties influence the interaction of the seat back frame and the safety belt. Seat integrated 3- and 4-point configurations with both non-rigid and rigid seat back frames were compared with 3-point configurations with anchor points on the car body. The LS-DYNA FE-analysis software was used in order to perform frontal crash simulations with a belted 50th percentile Hybrid III dummy model as occupant. The belt-webbing distribution between the lap and the torso belts via a slip-ring and in combination with a non-rigid seat back frame had an advantageous influence concerning the loads of the upper neck and injury criteria compared to a system with no belt-webbing distribution.

  • 171.
    Gersborg-Hansen, Allan
    et al.
    Department of Mathematics, Technical University of Denmark, Lyngby, Denmark.
    Berggren, Martin
    Department of Information Technology, Uppsala University.
    Dammann, Bernd
    Informatics and Mathematical Modelling, Technical University of Denmark, Lyngby, Denmark.
    Topology optimization of mass distribution problems in Stokes flow2006In: IUTAM Symposium on Topological Design Optimization of Structures, Machines, and Materials. Status and Perspectives / [ed] M. P. Bendsoe, N. Olhoff, O. Sigmund, 2006, p. 365-374Conference paper (Refereed)
  • 172.
    Girhammar, Ulf Arne
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A simplified analysis method for composite beams with interlayer slip2009In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 51, no 7, p. 515-530Article in journal (Refereed)
    Abstract [en]

    A simplified static procedure is proposed for analysing and designing composite beams with interlayer slip. The method is parallel to the Eurocode 5 method, but it is general in nature and can be applied to arbitrary boundary and loading conditions. In contrast with Eurocode 5, a general and correct way of choosing the effective beam length of the problem is given by the present procedure, which is that the effective beam length equals the buckling length that is found in the corresponding column buckling problem. The procedure predicts the deflections and internal actions and stresses, in principle by replacing the fully composite bending stiffness (EI(infinity)) with the effective (partially) composite bending stiffness (EI(eff)) in the expressions for these quantities in the corresponding fully composite beam. This effective bending stiffness depends on two non-dimensional parameters: the composite action parameter (shear connection stiffness) and the relative bending stiffness parameter. The method is applied to a number of simple practical cases and the results obtained have been compared with the exact values. The applicability of the simplified analysis procedure was found to be very good, except for interlayer shear stresses. The error in the Eurocode 5 procedure, as compared with the method proposed in this paper, can in some cases be up to almost 30% depending on the boundary conditions.

  • 173.
    Girhammar, Ulf Arne
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Composite beam-columns with interlayer slip: approximate analysis2008In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 50, no 12, p. 1636-1649Article in journal (Refereed)
    Abstract [en]

    An approximate second order analysis procedure for composite beam-columns with interlayer slip subjected to transverse loading and axial compressive loads is developed. The magnification factors to be applied to the first order solutions in order to estimate the deflections and internal forces obtained by the second order analysis approach are presented. The method of applying magnification factors to internal axial forces is discussed. The approximate second order analysis procedure is developed for the four Euler cases with various transverse load conditions. The procedure is applied to and the accuracy is illustrated for simply supported partially beam-columns of steel and concrete, and timber and concrete with different bending stiffness and interlayer slip properties. The deflections and internal forces obtained by the approximate method compared extremely well, except for slip forces in case of very flexible shear connectors, with those obtained by the more rigorous second order analysis approach for different composite action (partial interaction) parameters (shear connector stiffness values). The study also shows that the magnification factor associated with the deflections can be utilized to estimate also the internal actions, except shear forces in case of very flexible shear connectors, in the second order case with minimal error for simply supported beam-columns. Thus. for members with shear connector stiffness of structural significance the proposed approximate method can be used in general for simply supported beam-columns. For other boundary and loading conditions, the approximate method needs to be re-evaluated. The approach of using one magnification factor greatly simplifies the analysis task for those components.

  • 174.
    Girhammar, Ulf Arne
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pan, Dan H
    Exact static analysis of partially composite beams and beam-columns2007In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 49, no 2, p. 239-255Article in journal (Refereed)
    Abstract [en]

    The ordinary differential equations and general solutions for the deflection and internal actions and, especially, the pertaining consistent boundary conditions for partially composite Euler-Bernoulli beams and beam-columns are presented. Static loading conditions, including transverse and axial loading and first- and second-order analyses are considered. The theoretical procedure is applicable to general loading and boundary conditions for uniform composite beams and beam-columns with interlayer slip. Further, the exact closed form characteristic equations and their associated exact buckling length coefficients for composite Columns with interlayer slip are derived for the four Euler boundary conditions. It is shown that these coefficients are the same as those for ordinary fully composite (solid) columns, except for the Euler clamped-pinned case. For the clamped-pinned case, the difference between the exact buckling length coefficient and the corresponding value for solid Columns is less than 1.8%, depending oil the so-called composite action parameter and relative bending stiffness parameter. Correspondingly, the maximum deviation between the exact and approximate buckling load is at most 2.5%. These small differences can in most practical cases be neglected. Also, the maximum theoretical range for the relative bending stiffness for partially composite beams and beam-columns is derived. An effective bending stiffness, valuable in the determination of the critical buckling load for partially composite members, is derived. This effective bending stiffness is also Suitable for analysing approximate deflections and internal actions or stresses in composite beams with flexible shear connection. The beam-column analysis is applied to a specific case. The difference in the approaches to the first- and second-order analysis is illustrated and the results clearly show the magnification in the actions and displacements due to the second-order effect. The magnification of the internal axial forces is different from magnifications obtained for the other internal actions, since only that portion of an internal axial force that is induced by bending is magnified by the second-order effect.

  • 175.
    Glim, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rangordning av projekt inom Vattenfall Eldistribution2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 176.
    Grahnström, Robert
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Langendahl, Truls
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Verkningsgradsförluster på kaplanturbin vid primärreglering2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the Nordic electric power system the power output must always, instantaneous be consumed. This is upheld by the load frequency regulation.

    In E.ON hydropower this type of regulation is partly produced by the Kaplan turbine. This means that the turbine is constantly in regulation. Because the different construction of the Kaplan compared with for example Francis and Pelton, the Kaplan has a regulation system for the runner blade. This regulation system and the system for the guide vanes react individually and differently on a regulation change, with the result that the guide vanes and the runner blades will be unsynchronized. The purpose of this exam work is to examine this reaction and how big lost in efficiency this carry. To four fill this purpose a method in three steps is created, divided into pre-study, data collection and analysis & results.

    The pre-study includes a study in the variation of the electric power system and how the Kaplan will react to these.  Later, under the data collection phase this variation is simulated while the data is collected by specially made measurement equipment. From the data collected under the data collection phase, an analysis and result calculation can be made.

    The data is collected from Edensforsens hydro power plant and the result is that the runner blade and the guide vanes are almost always wrongly synchronized during load frequency regulation. But this fault is not mainly caused by different regulation speed but due to hysteres in the runner blade regulation system. The highest point of error is 0,54°, which is considered a lot. . Unsynchronized runner blades leads to an efficiency loss of 0,3 % compared with fully synchronization. The results are not statistically significant.  

    The report also makes suggestion on how the method can be improved, an alternative method and how the regulation errors can be avoided.

  • 177.
    Granholm, Mikael
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Översyn och optimering av kylsystem vid Norrlands Universitetssjukhus2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Västerbottens Läns Landsting arbetar kontinuerligt för att minimera sin verksamhets negativa påverkan på miljön. För att göra detta har de satt upp mål för 2020. Detta examensarbete kommer att försöka hjälpa dem att uppnå sina mål om en minskning med 17 procent av den specifika elanvändningen och en minskning med 22 procent av den specifika värmetillförseln jämfört med nivån år 2009.

    Syftet med detta projekt har varit att bidra till en ökad kunskap om hur kylsystemet för närvarande används och undersöka möjligheterna för en mer effektiv drift. Detta arbete fokuserar på tre huvudaspekter, driftsäkerhet, ekonomisk vinning och energieffektivitet. Målet med projektet har varit att undersöka tre eller fyra förbättringsförslag relaterade till de ovan nämnda aspekterna.

    Arbetet har delats upp i två delar för att uppnå projektets syfte och mål. Till att börja med en allmän översyn av kyltillförseln till Norrlands universitetssjukhus, och därefter en undersökning av de förslag som tagits fram. Granskningen har bestått av bearbetning av ritningar, driftkort och befintliga data. Data fanns främst tillgängligt för 2012. Översynen resulterade i en lista med nio förslag. De metoder som har använts är dels energiberäkningar i Excel, simuleringar av driftfall, riskanalys och stokastisk analys.

    Det viktigaste resultatet av översynen ligger i potentialen att minska den abonnerade maxeffekten från fjärrkyla. För att erhålla tillräckligt underlag för en investering bör en kylmaskin i byggnad 10B loggas. Tre förslag har undersökts utförligare, optimerad reglering av energitillförsel med en uppskattat sänkning av toppeffekten på 400 kW, energilager för kyla med en sänkning på ca 0,2 kW/kWh lagerkapacitet samt en sammankoppling av två kylnät som främst ökar redundansen i systemet.

  • 178.
    Granlund, Alexander
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Frostskyddsreglering i batterivärmeväxlare: Utvärdering av värmeväxlare av modell Ecoterm och Econet2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master’s thesis was written in collaboration with Fläkt Woods in order to evaluate the frost protection control of two run-around coil heat exchangers, their older model Ecoterm and their newer model Econet. The frost protection of Ecoterm is only reliant on the temperature of the liquid circuit whereas Econet also regards the dewpoint temperature of the exhaust air, as to not activate the frostprotection unnecessarily. Ecoterm uses bypass control for frost protection and defrosting whereas Econet first increases the liquid flowrate before initiating bypass control. The evalutation is built upon data collected from the university hospital in Umeå, NUS, mainly during february 2018, with a minimum outside temperature of -23°C. Ecoterm starts defrosting when the liquid temperature reaches -5°C, which correlates to an outside temperature of -14°C irregardless if there is any risk of frost growth, which there was not during the measuring period. For Econet the results were more difficult to interpret, but imply that bypass control only was nescessary at two occasions during the whole measuring period. This is partly due to the design of Econet, which integrates the additional heating, normally reserved for a separate battery, into the heat exchangers liquid circuit. The results for Ecoterm show the limitations of single parameter controlled frost protection and why better frost protection control is necessary for highly efficient heat exchangers. For quantifiable results further studies are required.

  • 179.
    Granlöf, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konceptutveckling av nya dentala implantat och tillhörande komponenter2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The technical development in dental care in Sweden is among the leading countries internationally. Self-manufactured products by dentists and technically complicated equipments are becoming more and more economically available for dental clinics, which has led to new concepts, ideas and products constantly emerging. Together with Lycksele Tandklinik, a degree project (Bachelor) on the mechanical engineering program at Umeå University has been carried out, where a concept of new dental components for use in digitally planned surgical procedures have been developed. The medical classification and procedure to CE-mark the components have been investigated and presented as it was requested by the clinic. The concept is under patent negotiations, which meant that the transparency of the components used were limited during the project.

     

    This report presents how the common technical methods used in dental care are applied. Methods that were used were machine production through 3D printing, milling and casting, to test materials for this concept. Surface scanning and CBCT (Cone Beam Computed Tomography) scanning are then used to compare the two data sets to determine whether the material is applicable in the digital planning, or if big size changes occur between the different data sets.

     

    The project resulted in six different tested and evaluated materials for one of the manufactured components, where one of the materials gave satisfactory results and can be used in the further development of the components and perhaps used in future clinical trials. A basis for CE marking and medical classification for the components have also been presented, which can be used in the further development of the components. Due to lack of time and the patent negotiations being extended, the implant concepts that have been developed could not be manufactured but will be tested later of 2019 after completion of the degree project.

  • 180.
    Grano, Jakob
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    NIBE - Uppgradering av värmepump2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    År 2009 introducerades en ny typ av luft-/vattenvärmepump av NIBE Energy systems. Den produkten vill man nu modernisera, samt göra mer lik de övriga produkterna i NIBE:s sortiment. Syftet är att göra en förstudie inför en sådan uppgradering. Man vill ha svar på om det går att genomföra en uppgradering, genom att utgå från en annan, nyframtagen produkt.

    Går det inte så vill man veta varför, men finns det möjlighet så ska ett koncept på en uppgradering tas fram. Konceptet ska då ge förslag på en konstruktion, användandet av befintliga moduler, möjlighet till produktion, kostnadsuppskattning, samt kvalitet och miljötänkande.

    På grund av sekretess, kommer det inte nämnas vilken produkt som ska uppgraderas, eller vilket utgångsobjektet är. Ingående komponenter och deras funktion finns däremot beskrivet i rapporten, då har spelat stor roll i tankegången bakom olika lösningar.

  • 181.
    Granqvist, Daniel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Klimatberäkningar för grundförstärkningsmetoden KC-pelare hos programmet Geokalkyl2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Vid projektering av väg- och järnväg är det viktigt att i ett tidigt skede som möjligt få en uppfattning om hur kostnaden kommer vara samt vilken klimatpåverkan arbetet kommer medföra.

    Det finns olika beräkningsprogram som utför både en kostnad och klimatkalkyl vid byggnation av väg- och järnväg. Exempel på beräkningsprogram är Geokalkyl och Klimatkalkyl.

    Tidigare har en fallstudie utförts mellan Klimatkalkyl och Geokalkyl där det visade på att vid användningen av grundförstärkningsmetoden kalkcement-pelare beräknar Geokalkyl klimatpåverkan 30 gånger så högt som klimatkalkyl.

    Syftet med det här projektet är att undersöka och vidareutveckla beräkningssättet för kalkcement-pelare hos programmet Geokalkyl.

    Grundförstärkningsmetoden kalkcement-pelare används bland annat för att stabilisera väg- och järnvägsbankar. Nedsättningen för pelarna är med hjälp av en maskin, blandningsbärare samt en tank förvarar blandningen. Vid nedsättning borrar maskinen ned till önskat djup. Då borren nått önskat djup roterar den upp samtidigt som blandning mängden släpps ut. Blandningen bildar tillsammans med jorden de fasta pelarna som stabiliserar marken.

    Geokalkyl gör beräkningarna i ett Excelverktyg där hänvisningar sker mellan olika blad i Excel. Ekvationen som gör beräkningen finns under fliken Indata. Alla arbetsmoment för kalkcement-pelare beräknas i samma ekvation där hänvisningar sker till separata informationsbilagor. Maskinförbrukningarna hänvisas till en dold Excelflik, Hagert. De justerbara parametrarna finns under fliken In parametrar. De parametrar som är justerbara är transportlängd och vilken klimatpåverkan pelarna har per längdmeter. Klimatpåverkan mäts i använda kWh och mängden koldioxidekvivalenter.

    För att uppnå syftet valdes följande utförande. Först inläsning på området, därefter tolkning av tidigare beräkningssätt och till sist uppbyggnad av nya beräkningssättet.

    Avgränsningarna för projektet är att endast se över specifika arbetsmoment som tillkommer vid användning av grundförstärkningsmetoden kalkcement-pelare hos Geokalkyl.

    Tidigare beräkningssättet hade bristfälliga hänvisningar till informationsbilagorna, samt felaktiga och bortglömda arbetsmoment. De beräkningarna som var felaktiga var dels att beräkningen tog hänsyn till en dimension men enligt informationsbilagorna skall den variera. Det var även en felaktig volym i pelarna, detta sågs genom att framställningsvärden per längdmeter pelare var med felaktig beräkning på dimension. Exempel på arbeten som tidigare beräkning ej tog hänsyn till var arbetet kring nedsättning, det vill säga förbrukning för maskinen och bäraren samt dess maskintransporter.

    För att bygga upp det nya beräkningssättet identifierades samtliga arbetsmoment kring kalkcement-metoden. Där respektive arbetsmoment fick en separat ekvation. Samtidigt så lyftes beräkningarna från Hagert till samma Excelblad som resterande beräkning. Alla antaganden från informationsbilagorna lyftes även in till Excelbladet. Genom att alla antaganden och beräkningar nu sker på samma Excelblad gör det beräkningen väldigt följsam. Förutom att beräkningen är följsam så är den lätt att justera genom att alla antaganden syns och att samtliga arbetsmoment har en separat ekvation. De arbeten som är utöver detta arbete måste ses över för att beräkningssättet skall kunna ersätta det befintliga i Geokalkyl.

  • 182.
    Granström, Jonas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effektivare fjärrvärmeanvändning med bättre exergiprestanda i fjärrvärmecentralen2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    District heating is today considered, one of the most important ways to increase our energy efficiency and reduce environmental damages with less emission from carbon dioxide. In Sweden around half of the homes and premises are connected to district heating and the numbers are increasing. 

    A lot of investigations during the 1990s have shown that return temperatures in the circulating system generally are too high. Along with this knowledge the importance and economical benefits has been spoken out but so far the overall work of cooling has gone slowly. 

    This being the point of view, focus is on reduced temperature of water in the primary circuit. Function and design of the district heating substations are investigated as one of the keys. Simulations and calculations have been made to compare an entirely parallel connection with a partially serial connection with focus on better exergy qualities of the substation. 

    The results show that the principle for how a substation is connected and the design of internal heat distribution can have an effect on the characteristics of the return temperature. It is possible to get a decrease in return temperature as outdoor temperature is falling instead of having an increased temperature, being the norm today. 

    The complete parallel connection figures as reference. Simulations show that the compared connection “Ventilation med återvinning” gives a flow rate weighted difference in return temperature of 5,1ºC. For the same connection but with the possibility of input mass flow from the return of the hot water before primary water the difference was 11,6ºC. 

    It is realistic to believe that this would have a corresponding effect on the system in larger scale. If so there is a possibility of better economy in the production of combined power and heat and also a need of system development to reach lower return temperatures. Dimensioning software for district heating substations to minimize destruction of exergy will also be needed.

  • 183.
    Grenbäck, Albin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av potentiell installation av bergvärme2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A housing society in the municipality of Umeå have under a period found interest in lowering their heating costs for the property. The property consists of 4 buildings in total with 3 of them being a multi-family residential containing 36 apartments in total and one of the buildings is an office building. The housing society was interested in knowing what a geothermal heating system would cost and how long the payback time would be.

    With the help of the old drawings the property was drawn in Revit and used to calculate the heat loss from different layers of the climate barrier and heat loss from the ventilation system. The internal heat generation was calculated by using standard values. When the total heat losses were calculated, and the internal heat generation was known the yearly energy needs were calculated by using a duration diagram.

    Then the yearly energy needs were compared to the actual yearly energy consumption of district heat and the software Nibe Dim was used to simulate three different alternatives.

    The investment that showed best result showed that the total cost for the investment would be 1 800 000 SEK and the annual saving 75 000 SEK/year. The payback time for the investment would however be as high as 24 years.

  • 184. Grimm, Alejandro
    et al.
    Etula, Jarkko
    Salh, Roushdey
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Kalén, Gunnar
    Segerström, Markus
    Brücher, Jörg
    Söderberg, Christer
    Soukup, David
    Pfeifer, Christoph
    Larsson, Sylvia H.
    Slagging and fouling characteristics during co-combustion of Scots pine bark with low-temperature dried pulp and paper mill chemical sludge2019In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 193, p. 282-294Article in journal (Refereed)
    Abstract [en]

    This paper shows how chemical sludge (CS) generated during wastewater treatment at a paperboard mill can be quickly dried at low-temperature and employed in bark-fired boilers to reduce slagging and corrosion problems. By using a cyclone-dryer operated at an inlet-air velocity of 110 m/s and a temperature of 90 degrees C, the dry-matter content of CS was increased from approximately 19 to 82%. The residence time of CS inside the cyclone was approximately 2 s when using the inlet-air velocity mentioned above. Disaggregation of the feedstock caused by collisions with the cyclone wall and between particles played a crucial role in enhancing the efficiency of heat and mass transfer. Three co-pelletized mixtures of Scots pine bark (SPB) and dried-CS were combusted in a 40 kW fixed-bed burner. Flue gas analysis was performed with a gas analyser. Coarse and fine ash were analysed by SEM-EDS and XRD. NO,, and SO2 emissions increased with increasing amount of CS in the mixtures. Mono combustion of SPB resulted in a large quantity of slag (i.e., molten ash) with a high degree of sintering (i.e., hardness of the slag), and ash deposits formed on heat transfer surfaces were rich in K2SO4 and KCI. Mixtures of SPB and CS were less prone to slagging, and the amount of alkali chloride in the deposits was reduced in favour of alkali sulphate formation.

  • 185. Grimm, Alejandro
    et al.
    Ohrnan, Marcus
    Lindberg, Therese
    Fredriksson, Andreas
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Bed Agglomeration Characteristics in Fluidized-Bed Combustion of Biomass Fuels Using Olivine as Bed Material2012In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 26, no 7, p. 4550-4559Article in journal (Refereed)
    Abstract [en]

    The bed agglomeration characteristics during combustion of typical biomass fuels were determined in a bench-scale bubbling fluidized-bed reactor (5 kW) using olivine and quartz sand as bed material. The fuels studied include willow, logging residues, wheat straw, and wheat distiller's dried grain with solubles (wheat DDGS). Bed material samples and agglomerates were analyzed by means of scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), for morphology and elemental composition. Furthermore, bed ash particles were separated by sieving from the bed material samples and analyzed for elemental composition by SEM-EDS and for determination of crystalline phases by powder X-ray diffraction (XRD). Chemical equilibrium calculations were performed to interpret the experimental findings of layer formation and reaction tendencies in both bed materials. Significant difference in the agglomeration tendency between olivine and quartz was found during combustion of willow and logging residues. These fuels resulted in inner layers that were more dependent on the bed material composition, and outer layers that have a composition similar to the fuel ash characteristics. The elemental composition of the inner layer formed on the quartz bed particles was dominated by Si, K, and Ca. In the olivine bed, the inner layer consisted mainly of Mg, Si, and Ca. Chemical equilibrium calculations made for both bed materials showed a low chemical driving force for K to react and be retained by the olivine bed particles, which is in accordance to the experimental findings. For the quartz case, the inner layer was found responsible for the initiation of the agglomeration process. The composition of the fewer and more porous agglomerates found after the experiments in the olivine bed showed neck composition and characteristics similar to the individual bed ash particles found in the bed or outer bed particle coating composition. For DDGS (rich in S, P, K, and Mg) and wheat straw (rich in Si and K), no significant differences in the bed agglomeration tendency between olivine and quartz bed materials were found. The results show that the bed particle layer formation and bed agglomeration process were associated to direct adhesion of bed particles by partly molten fuel ash derived K Mg phosphates for DDGS and K-silicates for wheat straw.

  • 186.
    Gruber, Andrea
    et al.
    SINTEF Energy Research, 7465 Trondheim, Norway.
    Chen, Jacqueline H.
    Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA.
    Valiev, Damir
    Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA.
    Law, Chung K.
    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
    Direct numerical simulation of premixed flame boundary layer flashback in turbulent channel flow2012In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 709, p. 516-542Article in journal (Refereed)
    Abstract [en]

    Direct numerical simulations are performed to investigate the transient upstream propagation (flashback) of premixed hydrogen–air flames in the boundary layer of a fully developed turbulent channel flow. Results show that the well-known near-wall velocity fluctuations pattern found in turbulent boundary layers triggers wrinkling of the initially flat flame sheet as it starts propagating against the main flow direction, and that the structure of the characteristic streaks of the turbulent boundary layer ultimately has an important impact on the resulting flame shape and on its propagation mechanism. It is observed that the leading edges of the upstream-propagating premixed flame are always located in the near-wall region of the channel and assume the shape of several smooth, curved bulges propagating upstream side by side in the spanwise direction and convex towards the reactant side of the flame. These leading-edge flame bulges are separated by thin regions of spiky flame cusps pointing towards the product side at the trailing edges of the flame. Analysis of the instantaneous velocity fields clearly reveals the existence, on the reactant side of the flame sheet, of backflow pockets that extend well above the wall-quenching distance. There is a strong correspondence between each of the backflow pockets and a leading edge convex flame bulge. Likewise, high-speed streaks of fast flowing fluid are found to be always colocated with the spiky flame cusps pointing towards the product side of the flame. It is suggested that the origin of the formation of the backflow pockets, along with the subsequent mutual feedback mechanism, is due to the interaction of the approaching streaky turbulent flow pattern with the Darrieus–Landau hydrodynamic instability and pressure fluctuations triggered by the flame sheet. Moreover, the presence of the backflow pockets, coupled with the associated hydrodynamic instability and pressure–flow field interaction, greatly facilitate flame propagation in turbulent boundary layers and ultimately results in high flashback velocities that increase proportionately with pressure.

  • 187.
    Gruber, Andrea
    et al.
    SINTEF Energy Research, Trondheim, Norway.
    Kerstein, Alan R.
    SINTEF Energy Research, Trondheim, Norway.
    Valiev, Damir
    Combustion Research Facility, Livermore, CA, United States.
    Law, Chung K.
    Princeton University, Princeton, NJ, United States.
    Kolla, Hemanth
    Combustion Research Facility, Livermore, CA, United States.
    Chen, Jacqueline H.
    Combustion Research Facility, Livermore, CA, United States.
    Modeling of mean flame shape during premixed flame flashback in turbulent boundary layers2014In: Proceedings of the Combustion Institute, ISSN 0082-0784, E-ISSN 1878-027XArticle in journal (Refereed)
    Abstract [en]

    Direct numerical simulations of freely-propagating premixed flames in the turbulent boundary layer of fully-developed turbulent channel flows are used for a priori validation of a new model that aims to describe the mean shape of the turbulent flame brush during flashback. Comparison with the DNS datasets, for both fuel-lean and fuel-rich mixture conditions and for Damköhler numbers lower and larger than unity, shows that the model is able to capture the main features of the flame shape. Although further a priori and a posteriori validation is required, particularly at higher Reynolds numbers, this new simple model seems promising and can potentially have impact on the design process of industrial combustion equipment.

  • 188.
    Gulliksson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jämförelse av energiberäkningsprogram för byggnader2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this work was to determine differences between the building energy simulation softwares IDA Indoor Climate and Energy (IDA ICE), VIP-Energy (VIP) and IES Virtual Environment (IES) with respect to functions, user experience and results from simulations.

    Of the three options for comparison the focus of this work was put on simulation results. A building was modelled in the softwares with identical input parameters where it was possible. Simulation results of the buildings total energy usage were analyzed. Sensitivity analyses of input parameters such as U-values, air flows, room temperature etc. were also performed.

    The results of the simulations showed that both IDA ICE and VIP calculated a total energy usage of 129 MWh per year for the building. IDA ICE calculated a specific energy usage, defined by Boverkets Byggregler (BBR), to 101.4 [kWh/(m2 year) heated area] while VIP calculated a usage of 102.9 [kWh/(m2 year) heat area]. The reason for the different results was that VIP calculated a smaller part of the heat recovered from the ventilation heat exchanger which led to a higher addition from the heating system.

    The sensitivity analysis showed that the U-value of walls, floor and roof were significant parameters. The reason for that was because they each stood for about 30 % of the total envelope area. The specific energy usage changed about 5 % when the room temperature changed with . Other significant settings and parameters were ventilation flow, shadow calculation settings in VIP and settings for the thermal bridges in IDA ICE.

    IDA ICE is an energy and climate simulation software well suited for calculation of power demand for heating and cooling, yearly energy demand, climate simulations etc. The software is user-friendly even though it is quite complex.

    VIP is an energy simulation software well suited for calculation of yearly energy demand. The software is easy to use but suffers from a few major disadvantages such as no graphical view of the building, poor compatibility with certifications etc.

    IES is an energy and climate simulation software. The software has a high learning curve and poor usability and had to be excluded from the simulations due to the time limitation of this work.

    It was concluded that for engineering consultants that works with energy and climate simulations of buildings, IDA ICE is the best choice.

  • 189.
    Gunnarsson, Nicklas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kabelfordon: Utveckling av kabeltrumlyft2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report contains most of the initial stages in the development of a product that will be used in the mining industry to feed in and out cable in boreholes and shafts. A new vehicle needs to be developed because the current vehicle is outdated and worn out, and lacks sufficient maneuverability. The new vehicle is going to create better work environment and ergonomics for future operators. The product includes a vehicle in the form of a tractor (tool carrier) that will carry different tools to perform tasks according to the specified requirements. This report focuses on the implements mounted in the rear of the vehicle, in form of a cable drum lift with hydraulic feed and a mobile crane. In order to determine the measurements of the current model of tool carrier (JCB Fastrac 4220), a visit to the distributor has been made to perform measurements that are used to dimension different components of the vehicle. This answers what the maximum height of a crane that can fit on the rear platform on the tool carrier without exceeding the total height of the vehicle.

     

    Different operating conditions were set according to the specification of requirements and based on these dimensions and hydraulic components such as motors and cylinders will be sized according to these operating conditions. The report also presents ideas on how the hydraulic system for these components could be constructed and regulated both passively and actively. The forces applied to the tool carrier were calculated based on established operating conditions to initially determine which counterweights are required to provide a safety margin against tipping in different planes. This is based on static and dynamic calculations as to which forces the implements will expose the tool carrier to in different load and operating conditions.

     

    A drive plats was designed, which serves to drive the rotation of the cable drum. Construction has taken into account given requirements, such as the need for no tools when changing cable drums, as well as manufacturing techniques and weldability in materials. The drive plate was also analysed with respect to fatigue by doing simulations in SolidWorks Simulation 2016. It was also investigated whether wooden cable drums, according to Swedish standards, are assumed to withstand the loads from the stated operating conditions.

     

    Because many different operating conditions needed to be tested, an Excel sheet has been developed that is used for all calculations in this report, which can be used in the future if any design changes needs to be made. There is also an adjacent degree project done by Niclas Larsson Isfelt  “Utveckling av kabelfordon”, who deals more closely with the design and strength calculations of the truss making up the rear cable drum lift.

     

    Calculations included in this work have reached their purpose, to demonstrate that forces are kept within set frames, for example to avoid tipping of the vehicle. Suitable hydraulic components have been dimensioned for the desired features of the implement. The new vehicle will create better work environment and ergonomics for future vehicle operators, as well as environmental benefits in form of a modern, lower-emission vehicle.

  • 190.
    Gunnarsson, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förstärkning av utsatta delar av elnätet med lokala energisystem: En undersökning om lokala energisystem kan implementeras i elnätet för att öka leveranssäkerheten av el till öar2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Det svenska elnätet har en mycket hög leveranssäkerhet på den el som skickas till kunderna och på många ställen kan elen levereras från flera håll till samma punkt. I utkanterna av elnätet som exempelvis öar, har inte elnätet samma säkerhet längre och om ett avbrott uppstår kan det vara vid dåligt väder. Framkomligheten blir svår och det kan ta tid att få dit en reparatör som kan laga felet.

    Syftet med det här arbetet var att undersöka om Umeå Energi Elnät (UEEN) skulle kunna använda sig av lokala energisystem för att motverka svåravhjälpta avbrott på öar och områden som är utsatta för den typen av avbrott, samt undersöka vilka komponenter som skulle krävas i en sådan lösning. Målet var att skapa ett lösningspaket som kan skalas om till olika antal abonnenter.

    Lösningen togs fram genom att först undersöka vilka komponenter som vanligtvis används i lokala energisystem. Därefter undersöktes och jämfördes komponenternas styrkor och svagheter med hjälp av fakta och resultat från vetenskapliga artiklar. De komponenter som inte var lämpade för den här typen av applikation eller som inte var tillräckligt bra, valdes successivt bort tills den bäst lämpade lösningen kvarstod. Den bästa lösningen blev ett litiumjonbatteri som laddas direkt av elnätet då den kräver lite underhåll, kan leverera höga effekter utan att ta skada och har en låg kapacitetsförlust. Anledningen till varför ingen lokal elproduktionsanläggning var med i lösningen beror på att ingen lösning är tillräckligt pålitlig för att kunna användas vid uppladdning av batterilagret och blir för stora om de ska användas till att göra ön självförsörjande. Detta beror på att de lösningar som är bäst lämpade som lokala elproduktionsanläggningar är för väderberoende och de lösningar som inte beror av vädret blir för stora och dyra för att vara rimliga alternativ.

    Storleksdimensioneringen av batterilagret skedde utifrån avbrottsstatistik för Umeås landsbygdsnät. Genom att göra en täthetsfördelning över landsbygdsnätets avbrottsstatistik kunde sedan den bästa fördelningsfunktionen passas in till det datat. Den fördelning som passade bäst till datat var en weibullfördelning som visade i sin kumulativa täthetsfunktion att drygt 80 % av alla avbrott som sker i ett område, pågår i tre timmar eller mindre. Genom att anta att avbrotten på öar också följer den här funktionen sånär som på att deras avbrott blir längre, kunde en dimensioneringsmetod tas fram. Metoden gick ut på att energilagret dimensioneras efter de tre på varandra följande timmar med högst energiförbrukning i ett givet område under ett år, vilket garanterar att strömförsörjningen kan täckas i tre timmar. Med tanke på att energiförbrukningen varierar mycket beroende på årstid och tid på dygnet kan batterilagret därför också klara mycket längre avbrott än tre timmar. Anledningen till varför just tre timmar valdes beror på att ett större energilager inte täcker upp så många procent fler avbrott än ett energilager på tre timmar och ett mindre energilager skulle inte klara tillräckligt långa avbrott. Det finns teknologier som inom några år kan ha mognat tillräckligt för att vara en bättre lösning än den som presenteras i den här rapporten, men den här lösningen är fortfarande tillräckligt bra för att kunna användas till att motverka långa avbrott och är en lösning som troligen skulle fungera länge efter att den installerats.

  • 191.
    Gustavsson, Isak
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energikartläggning och energioptimering av bergtunnel: Ett arbete i Umeå Energis regi kring bergtunnelns energianvändande samt optimering av ventilationen.2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Umeå Energi is a company that will be needed to map the use of energy in their facilities. This thesis is an indication of how this mapping will be like and what the result of the tunnel will show. Together with Umeva, Umeå Energi has a 3,5 kilometres long tunnel where the district heating and district cooling pipes goes. There are also pipes for sewer and drinking water. More thoroughly the thesis shows the energy use of the tunnel and also problem solving for better energy efficient considering ventilation. The quality of air in the tunnel is also analysed where the relative humidity of air is the most studied. The aims of the work are that Umeå Energi can reduce their electrical energy use and that they will get a better knowledge about the air quality in the tunnel. Measurements that where done was for some of the electric devices in the tunnel and there were also previously measurements done for the relative humidity of air, temperature and radon. The payments that has been for the tunnel under 2014 comes from an electrical energy use at 180000 kWh. An investigation about the electricity to the tunnel is done in the thesis and the conclusion is that the real electrical energy use of the tunnel should be 200000 kWh for 2014. The total energy use of the tunnel for 2014 is 460000 kWh, where heating and electricity are included. The analysis of the humidity problem results in that the inlet temperature of air is too high in relation to the air temperature of the tunnel and also that there is an inflow of small water amounts on several parts of the tunnel. Through these factors the relative humidity of air gets more worse and gets as high as 83-84 % in the tunnel. It also comes forward that one of the fans may bring polluted air to the tunnel. If the old fans are replaced by new EC-fans the electrical energy use will reduce. If all the fans would be replaced it gives a positive annuity of 10100 SEK/year but if the fan at Uminova not is replaced it gives a positive annuity of 11200 SEK/year. The payback time of the later choice is approximately 4 years. 

  • 192.
    Gyllander, Joakim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Manuellt driven timmertransportör till privat sågverk: Framtagning av koncept2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to develop a workable concept for a timber transporter to ease up the work with managing the log transport to and from a sawmill in Nyland, this with only the power source of one person.  The thesis is based on a requirement specification that was defined in collaboration with the client.                  

    The work began by analysing the scope and then a survey of commercial solutions was analysed, after that a creative process resulted in concept sketches. Different designs on the timber carrier were made and then by a selection one design concept was drawn up in a CAD software.  Through specific construction materials, certified by ISO 9001 standards, and analysis of specific load cases on the timber carrier, the strength was theoretically calculated and verified. These results were then compared with the results of a FE-analysis made by a FEM software. This method enables to investigate the critical points more closely by comparing the computer calculations with the manual calculations, which helps to form a deeper understanding of structural strength for the timber carrier. In this particular case, the results showed decent matching values.  

    This work resulted in a timber wagon on rails. It can handle the largest log the saw in Nyland probably can handle without any problems, i.e. a log with a diameter of 0.7 meters and 6.5 meters in length, with a weight of about 1.3 tonnes. The timber transporter can withstand loads up to 15 tons over hundred thousand load cycles. The fatigue calculations show that the welds and the design have a very long lifespan.

  • 193.
    Gårdbro, Gustav
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Techno-economic modeling of the supply chain for torrefied biomass2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Torrefaction and densification of biomass can provide an important piece in the puzzle of phasing out fossil fuels in favor of renewable alternatives. This new energy carrier shares many of the advantages with fossil coal in terms of energy density, hydrophobicity and burner feeding but is carbon neutral and renewable. It also lacks the challenges of many other renewable alternatives, especially irregular availability.

    A model was developed in Excel as sales support for BioEndev, one of the leading actors in the process of taking torrefaction to a commercial market, assessing the black pellet supply chain from feedstock to end user and comparing it to white pellets. Data was obtained from literature, industry and BioEndev. The model can be used for different parameters for price of feedstock, capital and operating expenditures, transport and handling costs and analyze 28 different cases. It also includes simplified calculations for energy input and greenhouse gas emissions.

    A case study for two different supply chains was performed with the model. One assessed a production facility in northern Sweden with distribution to a consumer in Denmark. The other a torrefaction plant in southeastern USA with distribution to a consumer in the Netherlands.

    The cost for delivering black and white pellets from Sweden to Denmark was found to be 33.0 €/MWh and 35.3 €/MWh respectively. For the case of delivering from USA to the Netherlands, the total supply chain cost was 27.6 €/MWh for white pellets and 24.7 €/MWh for black pellets.

    Suggestions for further work are to 1) develop the model outside this study’s limitations, for example by adding integration options for the torrefaction facility or by different end user configurations, and 2) expand the scope to also comparing black pellets to coal to see how big the gap is and which political incentives that could shrink this gap. 

  • 194.
    Gåsste, Filip
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av byggnad M7 i Umedalen: Energikartläggning med förslag till energieffektiviserande åtgärder ur en ekonomisk synvinkel2016Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    In Sweden, housing and services use about 40 % of all energy in which households and other premises stand for 90 % of these. The Parliament has decided that energy consumption must be reduced by 20 % to year 2020 and by 50 % to year 2050. Due to energy efficiency there are great savings to be found in costs, indoor climate and energy. The purpose has been to recommend cost efficient measures to lower the energy consumption. An energy survey has been made in a building, M7, located in Umedalen, Umeå belonging to Balticgruppen AB. The energy performance is 136 kWh/m2*year according to the energy declaration. The calculations of the energy measures result in a drop of energy usage by 66 % to an energy performance of 46 kWh/m2*year and a payback period of 8,5 years. The most cost efficient measures are made in the ventilation with the lowest payback period of only 3 days.

  • 195.
    Gåsste, Filip
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Uppföljning av energikartläggning: Hedbergska skolan i Sundsvall2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The world faces major challenges to cope with global warming and climate change. As a step in limiting temperature rise by two degrees, the UN Climate Change Conference in Paris 2015 decided on a binding climate agreement to begin in 2020.

    In order to achieve the energy goals of the municipality of Sundsvall in reducing energy consumption by 20%, a number of projects with high energy savings in municipal property are being implemented. WSP Systems was contacted in 2014 and preformed an energy survey in the school “Hedbergska skolan” to identify measures for reducing energy usage, resulting in the pre-study report "Förstudie energieffektivisering". The result of the energy audit resulted in the energy saving project "Hedbergska Energispar" which includes various types of measures and renovations.

    The purpose of this work is to evaluate the potential of energy savings and the cost-effectiveness in the measures recommended in the report Förstudie energieffektivisering.

    In order to improve future energy projects, this work will present different kind of suggestions of improvements in the approach of energy surveys.

    In 2013 the energy use of Hedbergska skolan was 2250 MWh of which 1600 MWh where district heating and 650 MWh where electricity. The energy performance of the school was 241 kWh/m2/year in 2013.

    The recommended energy measures in Förstudie energieffektivisering where calculated to decrease energy consumption by 35,5% and to result in an energy performance of 157 kWh/m2/year. These energy savings where obtained by actions including; changing windows, new ventilation system and new indoor lightning system.

    The project, Hedbergska energispar will have a decrease of energy usage by 41,3% and an energy performance of 143 kWh/m2/year when finished, without changing the windows. However, this comes with high costs.

    There are some difficulties in comparing the result of the energy savings project to the energy audit report since the project differs in some ways from the pre-study. Therefore, it is difficult to draw conclusions from this. As a consequence, the calculation presented in the pre-study energy audit are affected by this and can no longer be used as a basis for actions. Recommendations based on the work with the evaluation are to clarify what the purpose of the energy audit is and what costs for actions are acceptable for the client. Energy calculations should be focused on more extensive calculations for indoor lightning and ventilation using the latest climate data.  

  • 196.
    Habchi, W
    et al.
    Department of Industrial and Mechanical Engineering, Lebanese American University (LAU), Byblos, Lebanon.
    Vergne, P
    Université de Lyon, CNRS, INSA-Lyon, LaMCoS UMR5259, Villeurbanne, France.
    Bair, Scott
    G.W. Woodruff School of Mechanical Engineering, Centre for High-Pressure Rheology, Georgia Institute of Technology, Atlanta, GA.
    Andersson, Ove
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Eyheramendy, D
    Department of Industrial and Mechanical Engineering, Lebanese American University (LAU), Byblos, Lebanon.
    Morales-Espejel, G.E.
    SKF Engineering and Research Center, Nieuwegein, The Netherlands.
    Influence of pressure and temperature dependence of thermal properties of a lubricant on the behaviour of circular TEHD contacts2010In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 43, no 10, p. 1842-1850Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to study the effects of pressure and temperature dependence of a conventional lubricant's thermal properties on the behaviour of heavily loaded thermal elastohydrodynamic lubrication (TEHL) contacts. For this purpose, a typical mineral oil (Shell T9) is selected and the dependence of its transport properties on pressure and temperature is investigated. Appropriate models are then developed for these dependencies. The latter are included in a TEHL solver in order to investigate their effect on the behaviour of circular EHD contacts. The results reveal the necessity of a thermal analysis including the pressure and temperature dependence of thermal properties for a good estimation of film thicknesses and mostly traction coefficients in circular EHD contacts operating under severe conditions. Numerical results are compared with experiments, showing a very good agreement over the considered ranges. This thorough validation of a thermal EHL framework for the calculation of film thickness and friction offers a previously unavailable opportunity to investigate the effects of variations in material properties.

  • 197.
    Haciömeroglu, Ömer
    Umeå University, Faculty of Science and Technology, Umeå Institute of Design.
    ERO-Concrete Deconstruction Robot2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    The world is changing. Big cities are attracting more and more population, millions every day and growing. Who among the megacity dwellers would want to wake up in the morning staring at a construction demolition site, dusty, rusty and noisy? The increasing need for an improved infrastructure within the mega cities evokes a big industry of building replacements. The complex combination of building materials and methods is making the de-construction and recycling the demolition waste material very difficult. Today's methods are very complex, time consuming and the end use of the by-products are very limited. Moreover all of these methods are further limited by governmental regulations and laws. These laws are held in order to keep the dynamic city life to be able to cope with the de-construction jobs running around the city. Reinforced concrete being the most celebrated and used structural element, how might we find a smarter way to de-construct it and re-use the byproduct more accurately?

  • 198.
    Haghighat, Mathias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Fixturer för punktsvetsning av gripkomponenter2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Cranab AB manufactures crane arms and grapples of numerous sizes and for different purposes, the manufacturing starts from unprocessed material to finished products. The author has done a bachelor thesis at Cranab, with the purpose of creating a new concept of welding fixtures for one model of their grapples. The concept should improve the simplicity and efficiency of using the fixtures daily and should correspond to current and future overall needs and requirements.

    Most of the project has been carried out using the CAD-software Inventor to design the fixtures, meeting the operator’s requirements. In correlation of constructing a fixture, a study of using hydraulics to increase the efficiency of clamping, has also been carried out and complied in this report.

    The result presented in this report is a fixture which has the properties of simultaneously clamping both the inner and outer claw, its compatible with a rotating base and the smaller welding areas are easier to reach. The fixture is also more user friendly both regarding placing and clamping the components correctly.

    The problem description is reflected throughout the work that illustrates what has been focused on and why. All problems have been addressed and are solved or partially solved. However, there are a number of questions that have emerged during the project that needs to be reviewed before manufacturing.

  • 199.
    Hagman, Henrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Co-firing complex biomass in a CFB boiler: ash transformation, corrosion control and materials selection2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The effects of greenhouse gas net emissions on global warming, stricter legislation on waste handling, and the pursuit of ever cheaper heat- and power production are all important factors driving the introduction of complex fuels in incineration plants. However - without fundamental knowledge regarding ash transformation, corrosion control, and materials selection – this introduction of potentially economically and environmentally beneficial fuels, might instead cause economic loss and environmentally adverse effects.

    The present work is a contribution to the transition from today's CO2 net generating energy conversion system, to a more environmentally friendly and cost-efficient one. This is done using scientific methods to generate knowledge concerning mechanisms of ash transformation, corrosion control, and materials selection, in a co-fired industrial scale circulating fluidized bed (CFB) boiler, using a novel and biomass-based fuel mix, rich in Na, K, Cl, N, S, P, Ca and Si. Fuel fractions, ashes, flue gas, deposits, and construction material samples have been collected and analyzed using various techniques, including scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray Diffraction (XRD). The experimental results have been evaluated and interpreted using chemical equilibrium calculations.

    The results of this work include:

    1) An analysis of; the failure and preventive maintenance statistics of the industrial scale CFB boiler at hand; the elemental composition of boiler ashes and deposits, the flue gas composition and elemental composition of a multitude of fuel fractions; correlations between boiler design, operational parameters, elemental composition of deposits and boiler availability; a boiler elemental mass balance revealing details regarding deposit buildup mechanisms; properties of the fly ash relevant to flue gas filter design; and findings regarding the nitrogen chemistry of the novel and nitrogen-rich fuel mix.

    2) Speciation and description of the overall ash transformation and fireside alloy interaction, enabling the implementation of on-line corrosion control which significantly inhibits superheater and dew-point corrosion in the boiler; and, an equation describing the sulfation potential of the fuel mix, as a result of the direct and indirect interactions between all major ash-forming elements.

    3) A literature review relevant for the co-fired CFB cyclone vortex finder alloy selection and corrosion at 880 °C; An alloy selection study including long term exposures of several commercially available alloys identifying materials that are more than twice as cost-efficient as the often used alloy 253MA; a suggestion of novel methods for both systematic comparison of heavily degraded alloys, and for alloy service-life estimations; a detailed analysis of heavily degraded alloys 310S, 800H/HT and 600, identifying the driving corrosion mechanisms of the VF alloy degradation, including aspects of how the alloy internal mass transport and fireside surface interaction develops over time.

    The knowledge gained during this project has been used in the improvement work of the Perstorp 50 MWth CFB boiler, improving the boiler availability with 7 %, reducing the overall energy conversion costs with around 1.7 MEUR/year.

  • 200.
    Hagman, Henrik
    et al.
    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.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effects on a 50 MWth Circulating Fluidized-Bed Boiler Co-firing Animal Waste, Sludge, Residue Wood, Peat, and Forest Fuels2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 10, p. 6146-6158Article in journal (Refereed)
    Abstract [en]

    This work is a part of an effort to maximize the operational safety of a 50 MWth circulating fluidized-bed (CFB) boiler located in Perstorp, Sweden, co-firing animal waste, peat, waste wood, forest residues, and industrial sludge. An increase in the CFB boiler availability reduces the use of expensive fossil fuel (oil) in backup boilers during operational problems of the CFB boiler. The work includes a thorough mapping and analysis of the failure and preventive maintenance statistics, together with elemental analysis of boiler ash and deposits, flue gas, and fuel fractions. Correlations between boiler parameters and boiler availability are sought, and recommendations regarding boiler design and operation are made. An explicit description of the boiler is made to allow for the use of presented material as future reference material. It was observed that the failure frequency is especially high where (1) rapid chloride-rich windward deposit buildup is combined with (2) high construction material temperature and (3) windward soot blowing. In areas where one of these factors was absent, a more moderate material loss could be seen. The flue gas average elemental composition can be regarded as close to constant as it flows through the series of heat exchangers. Thus, the significant differences in deposit buildup of different flue gas cross-sections cannot be a result of changed average flue gas composition. The areas of the steam tubes suffering from rapid material loss are also exposed to high deposit rates. Downstream of a well-defined temperature threshold in the secondary superheater, neither material loss nor substantial deposit buildup could be seen. Tube deposits are dominated by Na, S, Ca, K, and P, but only Na, K, and S are enriched in the windward tube deposits relative to the fly ash bulk composition. The temperature of the flue gas is the major parameter governing the rate of deposit buildup in the boiler heat exchangers. Of the fuel nitrogen, 95 wt % leaves the process as N-2(g). Fuel mix ash content analysis via a separate ashing of different fuel fractions by heating to 550 degrees C does not reflect the ash content of the fuel mix correctly. The soot blowing angle of attack on the deposits should be regarded in areas with rapid deposit growth when boilers and soot blowers are designed to allow for efficient tube cleaning. The use of heterogeneous fuel in the boiler creates strong variations in fuel, flue gas, and particle composition and makes it increasingly important to have online measurements to be able to understand and control the furnace chemistry. The filter ash in the flue gas baghouse filter effectively sorbs HCl(g) and NH3(g) from the flue gas already without the addition of sorbents. Online flue gas measurement to control the furnace chemistry must therefore be installed upstream of the filter to enable accurate control. Also, a significantly larger filtration area can be installed in the baghouse filters with a slight increase in cost, to allow for efficient use of the ash as free of cost sorbent and lowered emission levels. Scanning electron microscopy analysis of the flue gas deposits shows that no pieces of ground bone, sand particles, or other relatively large flue gas particles contribute directly to the deposit buildup. White crystals rich in N and Cl, most likely ammonium chloride, precipitate downstream of the flue gas filter. The precipitation interferes with the dust emission measurement and forces a reduced usage of waste-derived fuels because of the exceedance of environmental limits. More expensive forest fuels are used to replace waste-derived fuels, resulting in a higher fuel cost.

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