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  • 1.
    Abrahamsson, Erik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Värmeöverföring från smälta till vattenkyld tapputrustning2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis work is done on behalf of Boliden Mineral AB at Rönnskärsverken.

    Kopparhyttan is an electric copper furnace for melting of copper concentrates and secondary materials in the form of ashes, metal scrap, crushed matte, slag and sludge.

    Depending on how the input material varies, the chemical composition of the melt will vary as well. Variations in the chemical composition of the melt also imply that the physical properties of the melt vary and the heat transfer between melt and tap block.

    A high heat load on the tap block during tapping of matte, results in increased wear and severe erosion of the tap channel and therefore the need of an understanding of the underlying causes to prevent and if possible avoid the high heat load.

    The completed analysis shows that a high heat load on the tap equipment mainly is associated with the copper content. A lower copper content leads to the melting point is lowered and also reduces the viscosity, leading to an increased mass flow. The increased heat load thus indicate an increased mass flow in combination with a reduced melting point, which means that the freezing of an erosion protective coating of matte on the inside of tapping channel walls becomes more difficult and thus increases the erosion on the tap equipment. Sulphur deficit, which is calculated from a chemical analysis of matte, showed no correlation to a high heat load and no connection between the sulfur deficit and the erosion of the tap equipment were successfully concluded.

    Measures proposed to reduce the wear on the tap equipment are increasing the flow of cooling water and a possible reduction of the tap channel diameter.

  • 2.
    Agrell, Daniel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimerad design och tillverkningsmetod av koncentrerande solfångare2015Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    The sun is our most important source of energy for us to be able to cope with the evermore pressuring climate threats. This has always been very clear for Absolicon Solar Collector AB in Härnösand, developers of concentrating solar collectors. The company has so far produced solar collectors which can produce both thermal and electrical power for mid-sized installations such as hotels and hospital. Now however, they are changing direction. Absolicon wants to address the many bigger industries with a demand for steam, in countries rich with solar radiation. Absolicon also wants to develop a production line for production of their solar collector, for deployment in the countries where the demand is the biggest.

     

    In a project partially financed by the Swedish energy department, a demonstrational production line will be built in Härnösand. The production line will be used to build a demonstrational field at HEMAB (Härnösands Energi och Miljö AB) with a new generation of solar collectors, optimized for steam production. The solar collectors built today has a problem with the reflector not getting an optimized shape throughout the whole collector. This has to be rectified since the demand on the shape of the reflector is higher on the new generation of solar collectors. This Is due to the use of a smaller receiver. Furthermore a mounting carriage using a new production method is to be developed for the production line. The mounting carriage should, by using vacuum, form and fixate the reflector of the collector while it also optimizes its shape.

     

    Tests was performed to examine how to optimize the shape of the reflector. A test rig was used to examine how a thin sheet of metal can be formed and fixated using vacuum while developing an optimized production method. A prototype carriage for production of 2 m long collectors using the new method was designed and constructed for evaluation.

     

    The results of the evaluation showed that the developed method is working well and that a receiver diameter of 19 mm can be used. The method is based on letting the edges of the reflector sheet hang free, which eliminates unwanted tensions in the reflector.

     

    The prototype which was built is ready for upscaling to a 6 m mounting carriage which will be able to produce the new generation of solar collectors for the demonstration field. A mounting process for production of solar collectors in a production line has been proposed which can shorten the mounting time and work load to less than 45 minutes and 1-2 persons per collector.

    The full text will be freely available from 2025-09-01 20:46
  • 3.
    Agrell, Elias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av massapumps- och mixerarbete vid Metsä Board Sverige AB, Husums Fabriker: Energibesparingsåtgärder vid blekeri 4 & 5 med jämförelse mot ny utrustning2014Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Husums plant has a selection of different pulp pumps at bleaching plant 4 and 5. The displacement- (HC-pump, Sund Defibrator PTD-60) and centrifugalpumps (MC-pump, MCA 42-200, MCP 30/20) are of interest in this report. The centrifugal pumps are controlled by throttle valves, which result in an energy loss. Chemical mixers are used to mix ClO2 into the pulp before proceeding into a holding tower where the bleaching process occurs.

    The energy demand of the different positions has been measured or calculated to be used in comparisons against new equipment. Quotations were requested and delivered from Valmet and Sulzer. The quotations were made with a production increase of 10 ADMt/h and plant compared to current equipment. Therefore energy need of the equipment in the quotation had to be recalculated to the same production output as when measurements were conducted to be comparable. Quotation of the pumps assumes the use of frequency inverters.

    A deeper investigation was made for 441PU255 which is located at bleaching plant 4. The drop leg level of the pump is controlled via a throttle valve. A frequency inverter is installed but not utilized to maintain constant pulp level in the drop leg. This was due to physical changes in the process not being compensated for in the control system. This caused the drop leg level to oscillate when automatic control was used. As a workaround the drive had been set at a constant speed. To investigate the potential savings, an attempt was made in which the speed was lowered from 1520 rpm to 1100 rpm, resulting in a power reduction of 82 kW or 342,081 Sek per year at a production of 36 ADMT/h. The experiment was done with slightly lower production output than desirable; because of this, savings will decrease slightly at higher outputs.

    Comparisons showed that considerable amounts of energy could be saved at all positions. However the investment cost is high and therefore favorable payback times can only be seen for some of the positions. The MC-pumps are oversized and in need of constant throttling therefore the majority of the energy savings is made through the installation of frequency inverters and not the pump upgrade.

  • 4.
    Ahlgren, Benjamin
    et al.
    Umeå University.
    Tian, Zhiyong
    Perers, Bengt
    Dragsted, Janne
    Johansson, Emma
    Umeå University.
    Lundberg, Kajsa
    Umeå University.
    Mossegard, Jonatan
    Bystrom, Joakim
    Olsson, Olle
    A simplified model for linear correlation between annual yield and DNI for parabolic trough collectors2018In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 174, p. 295-308Article in journal (Refereed)
    Abstract [en]

    This paper proposes a simple method for estimating annual thermal performance of parabolic trough collectors (PTCs) based on a linear relation with annual DNI for a certain latitude. A case study with simulations for a novel concentrating solar collector in 316 locations for three operating temperature scenarios worldwide was carried out and showed promising results for the latitudes and continents investigated. For a certain latitude and mean operating temperature, the annual yield of a PTC was found to be linearly proportional to yearly DNI. The proposed method will serve as a simplified alternative to the steady-state and quasi-dynamic methods already used. Estimating performance based on yearly DNI can be used by design engineers to do quick preliminary planning of solar plants. Customers can also use this method to evaluate existing solar collector installations. A TRNSYS/TRNSED tool that uses a steady-state model has been developed to carry out the simulations and it has been validated against a PTC array at Technical University of Denmark (DTU). The results show that the simplified method can give reliable estimates of long-term performance of parabolic trough collectors.

  • 5.
    Al-Hasnawi, Hassan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Solar Heat in Industrial Processes: Integration of Parabolic Trough Solar Collectors Dairy Plants and Pharmaceutical Plants2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The industry sector accounts for a high share of the final energy consumption, with industries in EU-28accounting for a quarter of the final energy demand. Studies also show that 45 % of the industrial heatdemand in EU-27 is in a temperature range that can be supplied with present day solar collectors. Despitethis large potential, solar heat faces obstacles hindering its growth in the industrial sector. The mostsignificant obstacle is the low insight of the industrial system designs and energy demands. Those arecrucial factors for the feasibility and dimensioning of solar heating systems. Three case studies aretherefore conducted in dairy and pharmaceutical plants in order to review the most promising integrationpoints for parabolic trough solar collectors in terms of annual heat demand, temperature level andintegration effort. Two case studies are performed in dairy plants and one in a pharmaceutical plant, alllocated in Sweden. The analyses comprised reviewing energy mappings, process and instrumentationdiagrams of processes and boiler systems, and hourly energy demand data. Simulations have beencarried out with Polysun for the processes with hourly energy data available.Four integration points have been determined to be high priority solar heat integration points in dairyplants, when considering annual thermal energy demand, temperature levels and integration effort.Those are the low pressure steam line, heating of feedwater, clean in place systems and pasteurizers.Solar heat integration concepts have been presented for all the aforementioned heat sinks andsimulations have been conducted for the low pressure steam line and heating of feedwater. A significantamount of excess heat is produced as a result of fluctuating heat demands and peak solar heat productionhours. Further investigation should be carried out, in order to review the potential of supplying excessheat to other heat sinks. Despite the reviewed potential of the clean in place systems and pasteurizers,lack of the hourly energy demand has hindered further analyses of those systems. It is thereforerecommended to conduct energy measurements before taking further measures.Two integration points have been identified in the pharmaceutical plant, namely autoclaves andmultiple-effect distillers. Solar steam generation concepts have been presented for both processes. Theautoclaves are provided with 4,5 bar steam intermittently, as they work with batches and can have ondutyand off-duty intervals ranging from 3-30 minutes. The multiple-effect distillers are providedwith 7 bar steam, which is of rather high pressure for the solar collectors model on which thesimulations are based. The heat demand of the distillers is more or less constant.It was generally easier to acquire data for the integration points at the supply level. For instance, all heatsinks at the supply level had energy demand data available, contrary to the process level. This inclinesadditional focus on integration to the supply level, if the extent of the feasibility study is to be kept to aminimum.

  • 6.
    Allard, Ingrid
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nära-nollenergibyggnader2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The new EU directive EPBD2, Energy Performance of Buildings Directive (recast), adopted 2010, specifies that all new buildings must be so-called nearly-zero-energy-buildings by year 2021. A nearly-zero-energy-building is a building with very high energy performance, which is provided with renewable energy to a large extent. How this should be interpreted and where the requirement is to be placed on energy usage is up to each country to decide. There is currently a debate about this going on in Sweden, and the Swedish Energy Agency has been asked to design a strategy to meet the goals for nearly-zero-energy-buildings. The environmental goal for reducing the carbon footprint by 2020 and 2050 is also closely linked to this question. In order to set a reasonable level of requirement for energy use, both economic-, technical- and environmental aspects must be taken into account. This report studies a new building area in Västra Sörhaga, Alingsås, to find out how to build it in order to achieve the standard for nearly-zero-energy-buildings. A wider study is also made to find out where it is reasonable to set the level of requirements for energy use for nearly-zero-energybuildings throughout the country. The energy calculation software VIP-energy is used for simulating four buildings, off different sizes, and studying their energy consumption.

    Where the system boundary is placed has a big impact on the outcome of the measurement of a building's energy use. EPBD2 determines that the building's energy performance should be a priority, before the supply of renewable energy sources. In order to attain a building with a high energy performance, an optimized construction performance is first required, with an airtight and highly insulated building envelope and a ventilation system with heat recovery, and then an efficient energy system and an efficient energy supply should be ensured. When this is reached, the focus can then be put on making sure that the energy supplied is renewable to as large extent as possible. It is therefore important to optimize the building performance first and then take the energy supply system and energy sources into account, whereby the building also has a low primary energy use and is supplied with as much renewable and environmentally friendly energy as possible.

    The Swedish Energy Agency’s proposes an energy requirement of half the current energy requirements as a goal for nearly-zero-energy-buildings. One example of energy reducing measures that would result in achieving this standard for a cottage in Kiruna is: elimination of thermal bridges, heat exchange of the ventilation air with 90 % efficiency, windows with a heat transfer coefficient of 0.7 W/m2K and doors with 0.6 W/m2K, airtightness of 0.2 l/s,m2 and a window proportion of 10 %. This is a stretch of what is possible to achieve with today’s technology. Heat exchangers with an efficiency of 90 % exist today, but since they require defrosting in cold climate, which decreases the real efficiency, it could be difficult to achieve in Kiruna. However, with future technological developments and experiences of building low energy buildings, this would be a reasonable standard for nearly-zero-energy-buildings throughout the country. It would also be advantageous to divide the country into more climate zones, or at least divide them more equally. The variation in energy use for a building is today much larger in the most northern climate zone than in the southernmost.

    thermal bridges, heat exchange of the ventilation air with 90 % efficiency, windows with a heat transfer coefficient of 0.7 W/m2K and doors with 0.6 W/m2K, airtightness of 0.2 l/s,m2 and a window proportion of 10 %. This is a stretch of what is possible to achieve with today’s technology. Heat exchangers with an efficiency of 90 % exist today, but since they require defrosting in cold climate, which decreases the real efficiency, it could be difficult to achieve in Kiruna. However, with future technological developments and experiences of building low energy buildings, this would be a reasonable standard for nearly-zero-energy-buildings throughout the country. It would also be advantageous to divide the country into more climate zones, or at least divide them more equally. The variation in energy use for a building is today much larger in the most northern climate zone than in the southernmost.

    It would be possible to use the passive house standard requirements for nearly-zero-energybuildings in the southern parts of Sweden, but it is not recommended in the north. Especially small buildings are very difficult to build in the passive house standard in cold climates today. To reach passive house standard for a small building in the northern most part of Sweden could require an indoor temperature no higher than 20°C and an airtightness of 0.1 l/s,m2. This is not reasonable, mostly because it is common to have a higher indoor temperature in Sweden and because this very high air tightness cannot be guaranteed today. The area in Västra Sörhaga, Alingsås, is realistic to build with requirements of passive house standard because it is in climate zone III, and that would almost certainly also satisfy the standard for nearly-zero-energy-buildings. If the area was built in the passive house standard it would result in a total specific energy consumption of around 50 kWh/m2 per year, which is 45 % of the energy use for the same area built to meet today’s energy requirements.

    The national board of housing’s proposed energy requirements for the revision of the construction rules for 2011 are deemed not to be ambitious enough and makes it very difficult to achieve environmental objectives by 2020. Further studies need to be made on the economic viability of buildings with low energy use, and in order to assess the amount of energy in a uniform manner, primary energy factors need to be developed. These should include both efficiency in manufacturing, energy form and energy sources. Energy sources, in turn, should be judged by the degree of renewability, access and storage capacity. Construction of low-energy buildings requires a large change in the existing construction market and energy structure. We have to start now to achieve this by 2021!

  • 7.
    Allard, Ingrid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy evaluation of residential buildings: Performance gap analysis incorporating uncertainties in the evaluation methods2018In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 11, no 4, p. 725-737Article in journal (Refereed)
    Abstract [en]

    Calculation and measurement-based energy performance evaluations of the same building often provide different results. This difference is referred as "the performance gap". However, a large performance gap may not necessarily mean that there are flaws in the building or deviations from the intended design. The causes for the performance gap can be analysed by calibrating the simulation model to measured data. In this paper, an approach is introduced for verifying compliance with energy performance criteria of residential buildings. The approach is based on a performance gap analysis that takes the uncertainties in the energy evaluation methods into consideration. The scope is to verify building energy performance through simulation and analysis of measured data, identifying any performance gap due to deviations from the intended design or flaws in the finished building based on performance gap analysis. In the approach, a simulation model is calibrated to match the heat loss coefficient of the building envelope [kWh/K] instead of the measured energy. The introduced approach is illustrated using a single-family residential building. The heat loss coefficient was found useful towards identifying any deviations from the intended design or flaws in the finished building. The case study indicated that the method uncertainty was important to consider in the performance gap analysis and that the proposed approach is applicable even when the performance gap appears to be non-existing.

  • 8.
    Almqvist, Jonna
    et al.
    SP Processum.
    Westin, Gunnar
    SP Processum.
    Öberg, Christian
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Luleå University of Technology, Department of Department of Engineering Sciences and Mathematics, Energy Science.
    Samförbränning av bioslam från massaindustrin i bubblande fluidiserad bädd2016Report (Other (popular science, discussion, etc.))
  • 9.
    Andersson, Björn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energiinventering av Universumhusets elanvändning2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete utfördes på uppdrag av Akademiska Hus AB i Umeå under våren 2017. I det här arbetet utfördes en energiinventering av elanvändningen i Universumhuset på Campus i Umeå. Akademiska Hus planerar en större ombyggnation av Universumhuset. Mindre renoveringar och ombyggnationer har genomförts under åren, men vissa system och konstruktioner är från byggåret 1970. Idag finns ett flertal olika hyresgäster och verksamheter inom byggnaden.

    I det här arbetet gjordes en inventering och fördelning av byggnadens årliga elanvändning. Fördelningen av elanvändningen beräknades dels efter objektskategorier men även för användningen av fastighets- och hyresgästel. Syftet med detta var att skapa ett underlag för energibesparande och energieffektiviserande åtgärder inför planerad ombyggnad. Utöver detta gjordes även analyser av byggnadens effektnivåer och utredningar för möjlighet till behovsstyrning av anläggningen.

    Utifrån inventering konstateras att byggnadens totala elanvändning är ca 1200 MWh/år, var av fastighetsel står för 53 % och hyresgästel för 46 %. Resultat för beräknad fördelning av byggnadens totala elanvändning visar att storköksutrustning står för den enskilt högsta elanvändningen på 23 % följd av belysning 19 %, värmepump 16 % och fläktar 13 %.

    Den årliga energianvändningen beror på utrustningens effekt och driftstid och fick i många fall antas. Elanvändnigen beror på flera olika anledningar och varierar under året. Stora delar av utrustningen är även behovsstyrd vilket ger stora variationer och ger en viss osäkerhet i den beräknade fördelningen.

    För en effektivare elanvändning föreslås generellt en utökad behovsstyrning för styrning av byggnadens system. Universumhuset har idag en stor del äldre utrustning vilket föreslås bytas ut mot modern utrustning med ny teknik. Även förändring av beteendet för användningen av utrustningen rekommenderas, vilket skulle kunna resultera i en betydlig energibesparing.

  • 10.
    Andersson, Cristian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förundersökning: Uppförande av vindkraftverk på Åsberget, Hudiksvalls kommun2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wind power expansion is often preceded with an extensive procedure where the technical, environmental and economic circumstances are investigated. Alongside of this there are also different permits that need to be granted before a wind farm can be built. This whole process takes several years and is both very costly and risky since projects often are discontinued before being a finished project.

    The aim of this thesis is to perform a preliminary investigation which examines the conditions for wind power expansion on Åsberget. The basis of this investigation has originated from a previously done initial assessment, made by a company that specializes in developing wind power projects. By using commonly used methods in the industry, the report tries to answer questions which are of great importance when developing wind power projects.

    Åsberget shows potential for wind power although there are some complications that may prevent an establishment. The municipality’s approach to wind power on Åsberget is unknown and thus a big question mark. Some of the buildings around Åsberget may also prove to be problematic as they have shown to have a high historical value.

    By relocating some of the wind power plants several of the presented problems can be minimized. If the project is continued suggestions for future work have been recommended.

  • 11.
    Andersson, Joakim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energibesparande åtgärder i en fastighet med skilda verksamheter.2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Houses in Sweden stand for a third of its annual final energy usage. Almost 60 % of this is used to heat the houses of the warm water used in it. A measure to reduce our impact on the environment is to increase of energy efficiency by the year 2020. The construction of new buildings in Sweden is relatively low when compared to the total amount of houses currently in use, this is why the need to not only build new efficient buildings, but to also refurbish the current housing stock is important.

    HSB is one of Sweden’s largest housing cooperative and has associations and real estates all across the country. HSB Umeå is one of 31 regional associations and has approximately 8 000 members. In addition to administer the real estate of its housing associations they also own their own real estate. One of those is the house Balder 9, an apartment building with 39 apartments, one office, two stores and one restaurant and was built 1984.

    The purpose with this study was to make a model of the house using current energy statistics, the energy usage of the house, and the blue prints of the house, this so that a number of energy saving measures could be tested on the energy usage of the house in the energy calculation program BV2. BV2 was chosen because the program is designed to examine similar problems, and has a flat learning curve in comparison to similar software. The measures that were tested were divided into three categories that affected the energy usage, one was measures on the climate shell of the house, one was measures affecting the heat usage and the last affected the electricity usage of the house. In addition to the three categories of measures, heat recovery from the exhaust air of the restaurant and the gray water from the house were calculated using values from the model.

    When the measures had been simulated one by one and the result analyzed, three joint measure packages was simulated on the model. These three were divided into measures that lowered the energy usage, measures that paid back their investment cost, and measures that only were simulated in BV2.

    The results given by the simulations was that the measures one by one lowered the energy usage of the house by 1,0 – 5,0 %. The measures that led to the highest saving in energy usage were the measures that lowered the electricity usage for lighting and power appliances, and the measure lowered the inside temperature. The simulation of the three joint measure packages resulted in a reduction in the energy usage by 14,4 – 20,8 %, and a reduction in the emission of carbohydrate equivalents by 15,9 – 18,3 %. The results showed that measures to increase the energy efficiency of buildings should be implemented in joint measure packages in order to attain a higher level of savings in buildings energy consumption that can be reached by individual saving measures.

  • 12.
    Andersson, Josefin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av värmesystem i Boliden AB:s anläggning vid Tara-gruvan2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the summer of 2009, WSP visited a facility adjacent to the Tara-mine at Navan, Ireland. The purpose of their visit was to control the ventilation system which was outdated. During the visit the inspector detected that their heating system also was in need of updating and that task led to this bachelor thesis.

     

    The overall aim of this work is to investigate how a modern heating system can be assembled to improve the indoor climate compared to an older system, where the primary target is to develop a proposal for the formation of a new system that meet the power requirements and today's climate demands.

     

    The study refers to a facility used as a changing room for the miners and as an office premise. The analysis focuses on the changing rooms as the indoor environment is especially inadequate with temperature and relative air humidity above recommendatory values for good indoor climate. In addition, the system is heated with large amounts of oil which contribute with large contaminations to the environment. Being able to moderate the impact the facility contribute to the surroundings is an additional motive for any investment.

     

    The analysis began with an examination of the system demands from the facility’s needs, followed by a search of potential components which could optimize a contemplated system. In order to be able to build this system theoretically correct the thesis established a flow chart. On the basis of the flow chart, the system components is conform adjusted to the facility’s needs, which includes the heating of domestic hot water, ventilation- and heating systems, as well an air dehumidification unit in the locker room. To examine the possibilities of improving the energy efficiency of this heating system, the project will evaluate heat exchangers, a heat pump and a dehumidifier, and a coupling to the existing ventilation and heating systems.

     

    The results are presented as a theoretical system that reduces the facility’s energy consumption and improves indoor climate. By utilizing the accessible thermal energy, the project also presents the economic advantages from choosing an efficient heat pump within the system.

  • 13.
    Andersson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A new energy strategy for controlling heating and ventilation systems for existing offices2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project shows a house that consists of two identical offices. This model is implemented into the energy simulation software IDA ICE. The thermal characteristics of the building envelope are set according to the Swedish Building regulation code of 1975 (1). The heating ventilation air conditioning system consists of water panel radiators and an air handling unit. These components are designed in order to fulfill the winter design conditions. The heating system is connected to a hot stratified tank whereas a cooling tank provides the cold flow to the air handling unit during summer time. Different local controllers of the panel radiators are tested in order to investigate both the behavior of the indoor temperature and the mass flow of the fluid. The results shows the tradeoff between the temperature of indoor air and the mass flow rate provided to the panel radiators. The P-controller regulates the amount of mass flow rate to the panel radiator according to the level of indoor temperature. It shows a more stable indoor temperature but more instable mass flow rate. The ON/OFF thermostat, set as control, shows large oscillations of indoor temperature and mass flow rate meanwhile the P-controller with set-point signal shows good potential, but when a higher proportional band is used both the temperature and mass flow rate becomes more instable. A PI-controller shows an indoor temperature more stable than the other controllers but an instable mass flow rate. Moreover, the electrical consumption of the auxiliary devices, such as the circulating pump are analyzed for a whole year. Huge differences in the electrical consumption of the circulating pump are detected just by selecting different control strategy. The first strategy used is with a thermostat measuring the outside temperature, this resulted in an electrical consumption almost twice as high as the second strategy. The second strategy is a P-controller with set-point signal that constantly measures the indoor temperature, which showed to be a good strategy for controlling the circulating pumps.

  • 14.
    Andersson, Pierre
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering genom dynamisk uppvärmning av en byggnad.2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Akademiska hus förvaltar Umeå Campus och har problem med att användningen av fjärrvärme överskrider den abonnerade effekten på deras abonnemang. Av den anledningen så valdes det att genomföra olika simuleringar av Teknikhuset där institutionen för Tillämpad Fysik och Elektronik är en av hyresgästerna. Med hjälp av simuleringar undersöktes möjligheten att undersöka olika konfigurationer och åtgärder.

    En modell skapades i IDA-ICE efter ritningar och de verkliga årliga behoven för fjärrvärme och el. Därefter användes modellen för att testa olika konfigurationer under kalla dygn där temperaturen kontinuerligt är mellan -18 till -25. Resultaten indikerarar att det finns möjlighet att sänka värmen i vissa rum som resulterar i ett minskat effektbehov vilket stämmer väl överens med hypotesen för scenariot. Ett av det andra problemen som förutspåddes var det fanns möjlighet att det skulle bli ökat missnöje av det termiska klimatet. Det på grund utav problem i närliggande rum och lokaler men det visade sig vara mycket begränsad påverkan av det.

    Det kalla dygnet visar att byggnaden uppvärm på det traditionella vis jämfört med en dynamisk uppvärmningsmodell skulle göra det möjligt att sänka effektbehovet med 9 % ifall man väljer att inte värma upp en av de tre våningarnas salar. Genom att göra en analys av hur bokningen av salarna visar det att det finns möjlighet att inför ett system där vissa lektionssalar som inte är bokade stängs för användning. Det skulle kunna skapa en lägre sänkning per dygn men på grund av de kontinuerliga användandet skulle det resultera i en större vinst. En simulering över möjligheterna att stänga av en lektionssal på våning två, tre och fyra i Teknikhuset gav en årlig effektsänkning med 1,2 % av fjärrvärmebehovet som om det extrapolerades ut över hela campus skulle spara på 100 000 kr per år. 

  • 15.
    Andersson, Robin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av slaggning vid förbränning av träpellets i värmeanläggningar: I sammarbete med Härjeåns Energi AB2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    The member states of the UN have united behind a convention on climate change 2015, the “Paris agreement”. To face the challenges of a required conversion to renewable energy, the dependence of fossil fuels need to be drastically reduced. Combustion of biomass has a god potential to replace fossil fuels in many applications. Pellets made from stemwood has a high energy value and is a good candidate to replace fossil fuels in small and medium scale heat and power production. To make pellets more attractive on the market, the delivered pellets need to have high quality and enable low maintenance and operational problems during combustion. Härjeåns Energi in Sveg would like to know more about the ash related issues like slagging and sintering, and how it can be avoided be measures related to handling, pellet production and end use (combustion). The overall objectives of the present work was to identify ash related problems during combustion of wood pellets in heating boilers, focusing on sintering and slagging, and to provide recommendations on measures how to avoid such problems for producers and individuals.

    This work with the report was divided into two parts. The first part included a research review on the subject. The second part included an investigation of the handling by Härjeåns Energi and their subcontractors. The research review was carried out by reading the research, mainly in scientific peer- review papers from the last 25 years. The investigation of the handling was carried out by evaluating analysis data of pellets, raw material and slagg samples.

    The results showed that the most important factor that influence slag formation is the concentrations of certain ash forming elements in fuel, such as silicon, potassium, calcium, sodium, magnesium aluminum and iron. Also ash content, combustion technology and combustion temperature are of importance. Substances in the fuels that are associated with slagging tendencies originate mainly from different kinds of contaminations, e.g. sand, soil and clay. This is most likely the case for Härjeåns Energi. The results also showed that the ash fusion temperatures of the raw material ash where constantly high during the weeks of the summer 2016. The remaining weeks of the year showed more varying ash melting temperatures. The produced pellets from Härjeåns Energi 2016 had a high ash molting temperature during the year of 2016, except in October. The exact reason behind the relative low ash melting temperatures is difficult to point out specifically in this work, and need more careful investigations. Overall, it is the pellets producer, the subcontractors and the manufacturer of the heating devices that have the possibilities to develop product and measures which avoid or reduces slagging related problems. The end users (customers) have very small opportunities to influence the outcome of the combustion of pellets. 

  • 16.
    Andersson, Ronny
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rosterkylning för biopanna-Ålidhems värmeverk2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rosterpannor är en väl beprövad förbränningsteknik som är vanligaste pannan för små och medelstora anläggningar i Sverige. Det finns många utföranden på rosterpannans rosterbädd som alla har sina för och nackdelar. Dock delar de samma problematik vid eldning av bränsle med ett högt värmevärde såsom biobränslen. Det höga värmevärdet leder till en hög förbränningstemperatur som tillsammans med många andra parametrar ger upphov till korrosion på pannans inre delar, däribland rosterbädden. Det finns två typer av rosterkylning, där ena är luftkylning och andra mer effektiva metoden är vattenkylning.

     

    Panna 7 är en del av Ålidhems värmeverk som används av Umeå Energi till att kapa effekttoppar hos fjärrvärmen. Denna panna eldar returträ med högt värmevärde och har problem med rosteröverhettning i rosterzon 2 vilket är i mitten av längden på hela rosterbädden. Rosteröverhettningen ger upphov till att rostret bryts ned och förutom det försämrar rosterbäddens alla funktioner för en optimal förbränning hos pannan. Denna rapport agerar som en dokumentationshandling åt UE som stöd  för P7:ans brister och lösningar på rosteröverhettningen. Rapporten innehåller kvantitativa lösningar som sedan fungerar som en förstudie vid intresse att genomgå en fördjupad undersökning innan förlagen implementeras i P7:an.

     

    Efter att ha undersökt rosteröverhettningen lokaliserats åtta olika förbättringsåtgärder som innefattar: kylning av stavarna i rosterbädden, utjämna primärlufts- och bränsleflödet, sänkning av värmevärdet hos det befintliga bränslet, konvertera till fluidbäddspanna och rökgaskondensering för att ta tillvara på fukten som vissa lösningar tillsätter till förbränningen. Där antingen konvertera till fluidbäddspanna eller installera vattenkylda stavar är dem mest tänkbara lösningarna vid fortsatt eldning av returträ. Konverteringen anses vara den mest framtidssäkra lösningen, men också den mest omfattande. Vattenkylda stavar är därför den åtgärd som verkar mest lovande eftersom en sådan lösning inte bara kyler stavarna, utan även gör så att förvärmningen av primärluften och luftmängdsfaktorn till förbränningen optimeras. Tidigare studier visar att det inte är tillräckligt ekonomiskt försvarbart med en rökgaskondensering för den aktuella returtemperatur på fjärrvärmen som kommer in till anläggningen. Vidare undersökning måste utföras för att kontrollera ifall anläggningen Graniten, som i dagsläget värmer returvattnet, kan förbikopplas.

  • 17.
    Andersson, Sara
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energisparåtgärder i samband med påbyggnad av nya bostäder: En fallstudie av Röda längan i IDA ICE2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As older buildings in our housing stock are in increasing need of extensive renovations, it further enhances our social requirements. It is then needed alongside with renovations to find whole measures that yields energy savings which also is financially profitable.

     

    In this report, we examine the possible energy savings alongside with the profitability of the energy measures connected with extensions of new housing on top of an existing housing. The current heating system of the building is replaced with geothermal heating, which is also working through to the ventilation system. Thereafter the building is extended with three new floors. The report also evaluates if an extension of new housing in the individual case is to be seen as an extension or a reconstruction, together with the demands of which are put on an altered building in accordance to PBL and BBR.

     

    With the help of the computational energy software IDA ICE, the affect from the different energy measures could be studied. The yearly economical savings was then compared to the cost of the different measures. The measures were deemed profitable if the value of the yearly savings exceeded the initial cost.

     

    For the specific case, the measures of energy savings gave an considerable improvement for the extension, both in energy but also in the economical sense. The investment of the extensions is to be seen payed via sales of apartments, and the payback on the actions taken on the existing building is estimated to within 10 to 15 years. for the individual case the possible yearly energy savings, after completed measures, is upwards of 74 percent, which translates to 130 kWh/m2 per year. This report also states that, in specific case, extensions of new housing is to be seen as an extensions and that four geothermal heating pumps are enough to reach sufficient energy savings together with economical profitability.

  • 18.
    Andersson, Sara
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Våningspåbyggnad av miljonprogrammets flerbostadshus: Simulering av energiprestanda i IDA ICE2016Student paper other, 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    During the years 1965-1974 around one million new housing were built in Sweden, this was also known as the “miljonprogrammet”. Today, nearly a third of the Swedish housing stock is from this particular period, and many buildings are reaching the end of their technical lifetime. After the new EU directives Sweden have decided on developing it's on national goals to achieve smart energy consumption. To speed up this development can the renovations of the existing "miljonprogrammet" executed in combination with storey extension.

     

    Sweden is also facing growing housing shortage, much like during construction of the “miljonprogrammet” as well as limited areas both in urban and densely populated areas. By refurbishing buildings from the “miljonprogrammet” in conjunction with a storey extension, new housing can be built in a resource and energy efficient way. This should also improve the energy performance of the existing building.

     

    In this project, the energy performance of an apartment building, typical from this time, was evaluated and then compared to a modified building with a storey extension. A reference house located in Nacka, Sweden was used to simulate the annual energy usage in the software IDA ICE. The simulation yielded an energy usage of 197.1 kWh/m2 for the reference building and 167.1 kWh/m2 for the building with a storey extension.

     

    After the project it became clear that a storey extension on a building from the “miljonprogrammet” improved the existing building's energy consumption. At best, a building like the reference house can improve the energy classification from energy class G to E. Residential densification using storey extension is beneficial in many aspects. In addition to lowering the total energy consumption of the building it also creates new homes in a resource efficient manner. Society must seek to create enticements for property owners to renovate and execute energy efficient measures on their properties. One such example would be three-dimensional property formation which is also an alternative form of financing investment such as a renovation.

  • 19.
    Andersson, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvärdering av energieffektiva armaturer2015Report (Other academic)
    Abstract [sv]

    Rapporten redovisar en genomförd uppföljning av den erhållna minskningen av varm- respektive kallvattenanvändningen genom installation av energieffektiva armaturer. Utvärderingen baseras på 23 månaders mätningar av den individuella vattenanvändningen i sjuttiosju lägenheter (21 test-samt 56 referenslägenheter). Testlägenheterna utrustades först med en tidigare generations vattenarmaturer, FM Mattsson serie 9000, vilka senare ersattes med den senaste generationens armaturer FM Mattson serie 9000E. I fem av dessa lägenheter har dessutom komplementerande mätningar gjorts vid de olika tappställena, WC undantagen. Användningen av varm- och kallvattenanvändningen i varje lägenhet har loggats med en tidsupplösning om 10 minuter. För att undvika påverkan av boendes frånvaro från lägenheterna har uppföljningen baserats på den genomsnittliga dygnsanvändningen av vatten för de tider de boende har nyttjat lägenheten. Lägenheter där byte av hyresgäster har skett under utvärderingsperioden har lämnats utanför utvärderingen. De erhållna resultaten visar på en besparing om cirka 30% avseende varmvattenanvändningen samt 15% avseende kallvatten jämfört med referensgruppen. Den erhållna uppskattningen är också konsistent med en teoretisk uppskattning av besparingen baserad på den mätta förändringen av kvoten mellan varmvatten- och kallvattenanvändningen i testlägenheterna.

  • 20.
    Andersson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Inventering av småskalig vattenkraft: En undersökning av gamla vattenkraftsdammars potential i Västerbotten och Västernorrland2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 21.
    Andreas, Domeij
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av en gammal kulturmärkt prästgård2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Reducing and improving the use of energy is something that is relevant in the current situation for both economic and environmental aspects. Energy goals have been set up to achieve a better and more efficient use of energy. This leads to buildings constructed as efficient as possible but it also involves existing buildings. This report investigates an old heritage rectory from the 1700’s that, with its high use of energy, will be analyzed and then simulated with a few measurements in the energy calculation program VIP Energy.

    The information about the rectory is limited. Many assumptions regarding the building’s construction and the occupants’ behavior were applied since documentation has been missing and since the building is currently empty. Svenska kyrkan is currently rebuilding the rectory since they intend to conduct business there in the future. A model was created in VIP with the goal to simulate the rectory when there still was activity in the building. The model were then simulated various measures that were additional insulation, renovation of windows and an installation of a FTX-system. The culture label has made measures that affect the façade, such as external insulation or replacing windows, disregarded.

    The results from the model showed that with all the measures together it is possible to reduce the specific use of energy of the rectory from 252 kWh/m

    2 to 111 kWh/m2 and thereby live up to the guidelines posted by The National Board of housing, Building and planning. Certain factors have deliberately been ignored such as moisture, due to time restrictions. The same thing applies to the economic part except for the ventilation where a lifecycle cost between a rotating heat exchanger and a plate heat exchanger has been compared to replace the existing exhaust system. The reason is that the ventilation is the most feasible solution for adaption to future use. LCC analysis showed a benefit to the rotary heat exchanger favor with a price difference for about 70 000 SEK towards the existing system, without installation costs or future reparations.

  • 22.
    Andreasson, Albin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konstant eller behovsstyrd ventilation i grundskolan: En jämförelse med hjälp av LCC-analyser2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Demand controlled ventilation is recognized as an option to constant air volume (CAV) ventilation. Capable of reducing the cost of energy usage, but having higher initial costs. This thesis investigates both these factors in order to see what gives the lowest LCC (life cycle cost).Using the case of a 1000 m2 primary school in Stockholm, Sweden, four different ventilation systems were analyzed: constant air volume (CAV) ventilation, CO2 controlled ventilation, CO2 and temperature controlled ventilation as well as occupancy controlled ventilation.All of the systems were constructed in the AutoCAD software, using the add-on MagiCAD. This made it possible to acquire detailed bills of materials that were exported to the accounting software Sektionsdata, which was used to calculate the initial costs of the systems down on a component level.The energy calculation software IDA ICE was used to perform simulations on both energy usage and indoor climate. Each system was simulated with three different sizes of occupancy.LCC was calculated for each system and occupancy using the net present value method, where CAV got the lowest with a wide margin. CO2 controlled ventilation got the second lowest LCC followed by CO2 and temperature controlled ventilation. Occupancy controlled ventilation got the highest LCC with a wide margin. This order did not depend on the size of the occupancy, but the LCC of the carbon dioxide controlled systems got smaller in comparison with the other systems when the occupancy was reduced.

  • 23.
    Anette, Nyström
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Undersökning av smarta energilösningar för en planerad livsmedelsbutik2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    På uppdrag av Hifab AB har detta examensarbete utförts under vårterminen 2015. En ny livsmedelsbutik ska etableras i Umeå, där Hifab AB har anlitats som generalkonsult av Coop Nord. I dagsläget finns endast ett utkast på hur byggnaden ska se ut eftersom byggnationen av butiken beräknas starta våren 2016. Detta innebär att det finns stora möjligheter att undersöka smarta energilösningar som kan appliceras på den framtida butiken. För att erhålla energistatistik att utgå från användes en Coop-butik i Kramfors som invigdes våren 2012 som referensbutik i detta projekt.

    Syftet med detta arbete var att undersöka olika energialternativ och energieffektiviserande byggtekniska lösningar för den planerade butiken. Detta för att den planerade Coop-butiken, tillsammans med andra framtida butiker, ska kunna byggas energieffektiv redan från början och för att driftkostnaden för butiken ska bli så låga som möjligt samtidigt som påverkan på miljön blir minimal. Detta projekt ska vara en vägledning i val av energisystem och byggtekniska lösningar för den aktuella Coop-butiken och även vid projektering av framtida livsmedelsbutiker i Sverige, framförallt i norra delen av landet.

    Projektet har innehållit två olika delar och ett flertal mål. Det första delmålet var att undersöka vilket av alternativen fjärrvärme eller bergvärme som är det mest ekonomiskt lönsamma för den nya butiken. Nästa delmål var att undersöka möjligheten och kostnaden för att installera solceller på den nya butiken. Målet var även att undersöka om det fanns alternativa sätt att tillgodose kylbehovet på jämfört med de kompressorkylmaskiner som finns i referensbutiken. I den andra delen av projektet var målet att bygga upp en modell av referensbutiken i ett energiberäkningsprogram och att simulera energieffektiviserande lösningar på denna. Detta för att undersöka hur mycket energibesparingar som kunde erhållas, framförallt i minskat uppvärmningsbehov per år.

    De metoder som användes för utförandet av detta arbete var studiebesök, intervjuer, kontakt med företag, litteratursökning och datorsimuleringar. Inledningsvis utfördes ett studiebesök på referensbutiken för att få en överblick över dess utformning och uppbyggnad. För undersökningen av fjärrvärme, bergvärme och solceller upprättades kontakt med olika leverantörer medan undersökningen av alternativa kylmetoder utfördes som en litteraturstudie. För den andra delen av projektet valdes IDA Indoor Climate and Energy (IDA ICE) att användas som energiberäkningsprogram. Referensbutiken modellerades i programmet och fick sedan fungera som grundfall på vilken ett antal, utvalda energieffektiviserande lösningar testades.

    De viktigaste slutsatserna i detta projekt är att när värmesystem ska väljas för den nya butiken så är fjärrvärme ett mer lönsamt alternativ när valet står mellan fjärrvärme och bergvärme. Slutsatsen för den del i projektet där solceller undersöktes är att det är en lönsam investering att installera solceller på den nya butiken utifrån de beräkningar som har erhållits från två leverantörer. Det bästa alternativet var en tunnfilmssolcell som gav en återbetalningstid på cirka sju år och en investeringskostnad på cirka 1,5 miljon kronor om statsbidraget erhålls. Av det totala elbehovet skulle då cirka 20 % täckas av produktionen från solcellspanelerna. Slutsatserna som kan göras när de energieffektiviserande lösningarna testades var att de två som gav störst energibesparing var behovsstyrning av ventilationsflödet och minskad belysningseffekt. Dessa två energieffektiviserande lösningar rekommenderas att undersökas närmare för att utreda möjligheten att implementera i den nya butiken.

  • 24.
    Apelqvist, Bo-Isak
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energikartläggning av LKAB:s underjordsgruva i Malmberget2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The LKAB mine in Malmberget used 258 GWh of energy in 2011, broken down by different types of energy where the share is shown as a percentage in the brackets below. • Electricity 183 GWh (71%) • Diesel 4897m

    3 or 49 GWh (19%) • Fuel oil 2378 m3 or 26 GWh (10%) • Energy consumption per tonnes of production was 15.91 kWh/ton The total quantity of crude ore mined in 2011 amounted to 16 193 tonnes and energy consumption was 257 609 MWh. Corresponding figures for 2005 were 14 035 tonnes of crude ore and energy use was 219 392 MWh, which gives a figure for energy consumption per tonne of 15.63 kWh/ton. Production has increased by 15.4% and energy consumption by 17.4% from 2005 to 2011. The increase is mostly because the mining occurs at greater depths and more energy is required to transport the ore to ground level. The energy audit has been carried out with respect to the mine in Malmberget and a comparison of energy use is made with information from a previous compilation from year 2007 (base year 2005). Year 2011 is chosen as the base year for this energy audit and it is then compared to the 2005 values to get a picture of how energy use has changed since then. The survey is updated with the new main level M1250 which began to be operational during the first half of 2011. The proposed efficiency measures in chapter 5 are discussed and anchored within the company. A sectioning of responsibility for the different areas of action is made with PS, PE / PI, TP and EP included as head responsible. The proposed measures with the greatest potential savings have been identified for each area of responsibility and should be prioritized. Priority actions are ventilation heat recovery, measurement and monitoring, and interventions for behavior change.

  • 25.
    Arnqvist, Kristoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av jordning för kraftproducerande anläggningar2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The safety regulations for grounding have been made stricter during later years; there are new rules and laws as well as recommendations and methods for how modern power producing facilities are to be grounded in a correct and safe manner. The purpose of this thesis has partly been to gather knowledge on these regulations as well as conducting an analysis of the grounding carried out at Vattenfalls hydro power plant G5 in Stornorrfors.

    A study of literature has been conducted and a site study was conducted with testing of earthing sites, measurement of currents and inspection of the hydro power plant G5 from a grounding perspective.

    Measurements show that the G5 power plant is a thorough and exemplary facility with very good qualities for handling earth faults., transients and preventing stray currents. The facility has a rigorous equipotential bonding where cableladders, stairs, pipes and exposed metal surfaces are all equipotentially bonded. The facility holds a good connection to earth at earthing sites when measurements revealed all earth sites having an earth resistance value less than 1 Ω. The earth sites and earth system showed only slight increases in impedance when measurements with high-frequency currents were carried out and the facility is deemed to be able to handle high-frequency currents in a satisfying manner.

    Through measurements of earth currents it was revealed that currents run in the earth wires, most likely due to the strong magnetic field generated by the generator, and it is unclear how these currents affect the earthing system and equipment over longer periods of time when some currents exceeded 10 A.

    No surge arresters were found by the facility or the transformer next to it, some were found however where the cable is replaced by hanging wires after the emergency power building. An inventory of surge arresters is recommended. The lighting protection system found on the roof of the facility should be repaired and possibly adressed in order to withstand damage caused by heavy snowfall. The facility is very exposed to the public and access to the facility should be restricted through fences and gates.

    Grounding a power producing facility today incorporates many different areas within electrical technology and therefore also holds a broad variation in how a safe installation is classified and examined. Making a facility "completely safe" is not obvious there will always be a need for compromises and considerations as no situation is similar to the next one in real life.

  • 26.
    Arén, Axel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    The effect of resident related input data on the specific energy use2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 27.
    Azizi, Shoaib
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Comparative Study of Influential Factors on Implementation of Energy Efficiency Measures in Single-Family Houses in Cold Climate2018Conference paper (Refereed)
    Abstract [en]

    A combination of factors, which include occupants and building related aspects, could motivate homeowners to implement energy renovation (ER). This study applies a comparative approach to assess perspectives of single-family homeowners towards different energy efficiency measures (EEMs). The aim is to unveil the factors that are effective on the residents’ attitude and decision making to implement an EEM or a set of EEMs. The analysis is based on a questionnaire survey conducted during spring 2017 among1550 owners of single-family houses in seven municipalities in northern Sweden. Approximately, 35% of respondents expressed their interest to install energy efficient household appliances and solar photovoltaic (PV) systems. The analysis suggests significant relations between the homeowners’ interest to implement thermal envelope measures and the quality of the house such as age and indoor environmental problems such as cold surfaces. The group of respondents, who reported their heating cost to be high, are more likely to be interested in implementing thermal envelope measures than other measures such as HVAC. Several socio-economic factors are found to be significantly related with homeowners’ interest to implement EEMs.

  • 28.
    Bassem, Mohammad
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förbränning av träpellets och pelleterad halm i en 40 kW rosterreaktor2012Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [sv]

    The project focus on combustion of softwood pellets and pellets in a 40 kW grate fire reactor at TEC-Lab. Dept Applied Physics and Electronics at Umeå University. Experiments were performed at four primary airs to fuel ratios (0.7 to 1.3), where aspects such as temperature profile, levels of gases (CO and NO), sintering-/-slagging and unburned fraction of the ashes were studied. Four different fuel loads were used for wood pellets (10, 20 and 30 kW) and one fuel load for straw (10 kW). Combustion of straw proved very difficult to ignite, and also led to other combustion-related technical problem such as slag formation due to the relatively low melting temperature-/-slag temperature of the straw. Causing undesired silicate melt on the grate. The straw was only possible to use low load operation (10 kW) because it was difficult to manage. The temperature of the bed varied between the studied cases with varying fuel loads and air to fuel ratios.

  • 29.
    Berggren, Thor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av värmesystem, förslag på effektiviseringar för att värma vatten/ballast för   modulära betongstationer2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis I examine the potential to recover some of the heat used to warm up ballast when the material is stored in ballast tanks, at an industrial sized concrete facility at outdoor temperatures below +5 °C. Three different cases with different heating applications are covered. All calculations has been made using 0 °C as outdoor temperature, results with varying outdoor temperature is shown in graphs at the end of the results chapter.

    Case 1, where the ballast is heated with humidified flue gas has a calculated estimated output of 506 kW, of these 506 kW, 67.5 kW can be recycled, which means that the theoretical percentage of recyclable power is 13.4%. Furthermore, the calculations show that the inlet temperature drops from 300 °C to 162 °C just above the ballast. The time for heating the material is in this case 5 minutes.

    Case 2, where the ballast is heated with dry hot air at a calculated estimated output of 10 kW, of these 10 kW, 7.6 kW can be recycled, which means that the theoretical percentage of recyclable power is 76.3%. Furthermore, the calculations show that the inlet temperature drops from 100 °C to 78 °C just above the ballast. The time for heating the material is in this case 16 hours.

    Case 3, where the ballast is heated with humidified air has a calculated estimated output of 85.3 kW, where all power is used to heat the ballast. The case is shown to work with a deficit of energy which means the ballast could absorb a lot more power than is actually available. Therefore, the percentage of recoverable energy is 0 %, and consequently the inlet temperature drops from 100 °C to 0 °C

  • 30.
    Berglund, Beatrice
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av dimensionerande temperaturer från värmeåtervinningsbatteri till frånluftsvärmepump2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There are a large number of houses that have no heat recovery in the ventilation systems at present. There is an option to install heat recovery batteries to the exhaust air ducts that is connected to heat pumps in order to meet energy reduction targets for 2020 and 2050.

    The purpose of this project has been to investigate how energy consumption and annual cost depends on the design temperatures of the heat recovery battery. The parameters that have been investigated are normal variations of:

    -          Exhaust air temperature

    -          The moisture content in the exhaust air

    -          Exhaust air flow over battery

    -          Liquid flow over battery

    The overall coefficient of performance (COP) of the system has been studied for heat pumps with or without variable speed. The efficiency has also been investigated when solar panels are connected to the system.

    Two batteries have been simulated, a traditional battery from Luvata and one needle pipe battery from Retermia. The two heat pumps which have been investigated are one heat pump from IVT and one industrial heat pump with speed control from Kylma.

    Calculations and simulations have been made in the program Coils and Microsoft Excel.

    The cases that have been investigated are:Case 1: Luvata battery connected to Kylma heat pumpCase 2: Retermia battery connected to Kylma heat pumpCase 3: Luvata battery connected to IVT heat pump

    A comparison of annual costs for heating water with a heat pump system or with district heating was made.

    The results from the calculations for the batteries show that the Luvata battery can absorb more heat than the Retermia battery in most cases, because of its higher temperature efficiency, about 81 % compared to 71 %.

    The COP for Kylma were shown between 3.9 and 4.1 and for IVT between 2.6 and 2.8. Case 1 and case 2 will have the best options with a total COP of about 3.8 for every parameter variation, while case 3 gives a total COP of about 2.5 for every parameter variation, when the total COP of the system were calculated.

    In the calculations of which case that is most profitable the answer is case 2, with an annual cost divided by the produced thermal energy about 390 kr/MWh compared to the case where a district heating exchanger were installed about 640 kr/MWh.

    The total COP and the annual costs can be concluded that case 2, when Retermia battery is connected to a Kylma heat pump, is the best option based on the calculations that has been performed.

  • 31.
    Bergman, Jonathan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Technical Solutions in Dimensioning an Industrial Torrefaction Facility2017Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    The full text will be freely available from 2022-05-31 15:55
  • 32. Bergström, Dan
    et al.
    Israelsson, Samuel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Dahlqvist, Sten-Axel
    Gref, Rolf
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Wästerlund, Iwan
    Effects of raw material particle size distribution on the characteristics of Scots pine sawdust fuel pellets2008In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 89, no 12, p. 1324-1329Article in journal (Refereed)
    Abstract [en]

    In order to study the influence of raw material particle size distribution on the pelletizing process and the physical and thermomechanical characteristics of typical fuel pellets, saw dust of Scots pine was used as raw material for producing pellets in a semi industrial scaled mill (similar to 300 kg h(-1)). The raw materials were screened to a narrow particle size distribution and mixed into four different batches and then pelletized under controlled conditions. Physical pellet characteristics like compression strength, densities, moisture content, moisture absorption and abrasion resistance were determined. In addition, the thermochemical characteristics, i.e. drying and initial pyrolysis, flaming pyrolysis, char combustion and char yield were determined at different experimental conditions by using a laboratory-scaled furnace. The results indicate that the particle size distribution had some effect on current consumption and compression strength but no evident effect on single pellet and bulk density, moisture content, moisture absorption during storage and abrasion resistance. Differences in average total conversion time determined for pellet batches tested under the same combustion conditions was less than 5% and not significant. The results are of practical importance suggesting that grinding of saw dust particle sizes below 8 mm is probably needless when producing softwood pellets. Thus it seem that less energy could be used if only over sized particles are grinded before pelletizing.

  • 33. Bergström, Dan
    et al.
    Israelsson, Samuel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Dahlqvist, Sten-Axel
    Gref, Rolf
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Wästerlund, Iwan
    Effects of raw material particle size distribution on the characteristics of Scots pine sawdust fuel pellets2008In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 89, no 12, p. 1324-1329Article in journal (Refereed)
    Abstract [en]

    In order to study the influence of raw material particle size distribution on the pelletizing process and the physical and thermomechanical characteristics of typical fuel pellets, saw dust of Scots pine was used as raw material for producing pellets in a semi industrial scaled mill (similar to 300 kg h(-1)). The raw materials were screened to a narrow particle size distribution and mixed into four different batches and then pelletized under controlled conditions. Physical pellet characteristics like compression strength, densities, moisture content, moisture absorption and abrasion resistance were determined. In addition, the thermochemical characteristics, i.e. drying and initial pyrolysis, flaming pyrolysis, char combustion and char yield were determined at different experimental conditions by using a laboratory-scaled furnace. The results indicate that the particle size distribution had some effect on current consumption and compression strength but no evident effect on single pellet and bulk density, moisture content, moisture absorption during storage and abrasion resistance. Differences in average total conversion time determined for pellet batches tested under the same combustion conditions was less than 5% and not significant. The results are of practical importance suggesting that grinding of saw dust particle sizes below 8 mm is probably needless when producing softwood pellets. Thus it seem that less energy could be used if only over sized particles are grinded before pelletizing.

  • 34.
    Blomqvist, Benjamin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rönntoft, Britta
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jet flow simulations of Baihetan hydropower station’s discharge surface spillways2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project was performed in order to determine if numerical simulations can be used to predict the spreading of a water jet that exits the discharge surface spillways of Baihetan hydropower station. If the spreading ranges can be predicted correctly using numerical simulations, the pressure distribution in the plunge pool downstream the dam can be determined. By being able to determine the pressure distribution, the spillways’ design can then be modified in order to optimize the pressure distribution and thereby minimize the damage on the plunge pool’s river bed. If the spreading ranges can be predicted correctly using numerical simulations it means that numerical simulations can be used as a tool to design future hydropower stations’ discharge surface spillways as a substitute to scale models which are commonly used to optimize the spillway design today.

    A simulation model of Baihetan Hydropower station’s discharge surface spillways was constructed. The model was constructed as two separate parts using the pre-processing software Gambit and then imported to the computational fluid dynamics software Fluent for numerical simulation of the water flow. The numerical simulations were performed with a transient flow, the k-ε turbulence model and the Volume of Fluid multiphase model. The models were simulated with a water level in the dam corresponding to when a massive flood has occurred which happens approximately once every hundred years. The results from the numerical simulation were then analyzed with the post-processing software Tecplot 360. Results in form of water spreading ranges when the jet stream hits the plunge pool were obtained from the numerical simulation and compared to data from an earlier performed experimental study where a scale model was used. The water spreading ranges were measured using a water volume fraction of 0-5 percent. The comparison was done to be able to determine if the results from the numerical simulations were accurate enough so that numerical simulations could be used as a substitute to expensive scale models when designing hydropower stations’ discharge surface spillways. A sensitivity analysis was performed where different mesh sizes were used and the Fluent setting double precision mode.

    The numerical results were acceptable when checking for convergence, meaning that the equations involved in the simulations were solved properly. The relative difference in water spreading range in the direction of the flow for the Medium mesh size was below 20 percent and thereby considered acceptable while the relative difference in water spreading range perpendicular to the flow was 60 percent for the Medium mesh size and thereby far from acceptable. Possible reasons for these deviations from the experimental results are the approximated uniform velocity profile at the inlet of the spillway and the used k-ε turbulence model. Considering the results obtained in this project, without more detailed study, the numerical simulations using k-ε turbulence model are not advised as a substitute for the experimental methods to determine water flow out of the discharge spill ways of hydropower plants. With more information about the conditions at the inlet and the use of a different turbulence model more accurate results may be obtained. 

  • 35.
    Bonthron, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förstudie för etablering av vindkraft vid Dåva kraftvärmeverk2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 36.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    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.
    Grimm, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Ash transformation chemistry during energy conversion of biomass2010In: Impacts of Fuel Quality on Power Production and the Environment, Saariselkä, Finland, August 29–September 3, 2010, 2010Conference paper (Refereed)
  • 37.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Grimm, Alejandro
    Luleå Univ Technol, Div Energy Sci, SE-97187 Luleå, Sweden.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå Univ Technol, Div Energy Sci, SE-97187 Luleå, Sweden.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ash Transformation Chemistry during Combustion of Biomass2012In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 26, no 1, p. 85-93Article in journal (Refereed)
    Abstract [en]

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

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

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

  • 39.
    Bozaghian, Marjan
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Xiong, Shaojun
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion characteristics of barley straw stored with CaCO3 using olivine and quartz as bed materials in fluidized bed combustion2017Conference paper (Refereed)
  • 40.
    Bozaghian, Marjan
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Xiong, Shaojun
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion characteristics of barley straw stored with CaCO3 using quartz and olivine as bed materials in fluidized-bed combustion2017Conference paper (Other academic)
  • 41.
    Breimark, Odd
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Undersökning av förutsättningar för icke-publik laddinfrastruktur2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

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

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

  • 42.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Transient model of a panel radiator2015In: Proceedings of BS2015: 14th Conference of International Building Performance Simulation Association, Hyderabad, India, Dec. 7-9, 2015, India, Hyderabad: International Building Performance Simulation Association (IBPSA), 2015, , p. 2749-2756p. 2749-2756Conference paper (Refereed)
    Abstract [en]

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

  • 43.
    Brännström, Emil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Underlag för kommunal- respektive gårdsbaserad biogasanläggning.2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 44.
    Burck, Robin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ENERGIEFFEKTIVISERING AV VENTILATIONSYSTEM I AITIK, BOLIDEN2015Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    The mine of Aitik is the largest open cast mine in Sweden that refines chalcopyrite. The chalcopyrite is being transported from the open cast mine beneath through a system of underground tunnels to a refinery above ground. There is a ventilation system in the tunnels that is controlled without knowledge of the requirement of ventilation’s force. Boliden has the intention of doing energy saving’s within the corporation. One alternative to save energy is to steer the ventilation. There’s an application called “Ventilation on demand” that steers the airflow of ventilation systems, which can be implemented in the current steering system 800xA. The concept of the application is to minimize the use of energy and both the application and steering system is a product of ABB. Before the implementation of the application a pilot study is needed to chart the airflow based on the requirement to sustain good working environment in the tunnels. The pilot study will contain a situation analysis and a series of measurements with different ventilation speeds. The result of measurement will tell how the ventilation speed affects the air quality in the tunnels and energy use of fans and district heating. The pilot study will also contain the result of cost- and energy savings by installing the application. ‘  The ventilation system contains five fans and two of them have frequency inverters. The air that is forced down to the system of tunnels is heated by district heating trough heating batteries. Skellefteå Kraft is the supplier of the district heating and the pellet boiler is located within the mining area. The situation analysis will be a reference to compare the series of measurements and present the possibilities of cost- and energy savings regarding the working environment in the tunnels.  The result demonstrates the possibilities of making energy savings up to sixty percent and still have a good working environment. The result also demonstrate that “Ventilation on demand” has a short payback time.

  • 45.
    Bychkov, Vitaly
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Modestov, Mikhail
    Law, Chung K.
    Combustion Phenomena in Modern Physics: I. Inertial Confinement Fusion2015In: Progress in Energy and Combustion Science, ISSN 0360-1285, E-ISSN 1873-216X, Vol. 47, p. 32-59Article, review/survey (Refereed)
    Abstract [en]

    The overarching objective of the present endeavor is to demonstrate the universal character of combustion phenomena for various areas of modern physics, focusing on inertial confinement fusion (ICF) in this review. We present the key features of laser deflagration, and consider the similarities and differences between the laser plasma flow and the slow combustion front. We discuss the linear stage of the Rayleigh-Taylor instability in laser ablation, short-wavelength stabilization of the instability due to the mass flow, and demonstrate the importance of the concepts and methods of combustion science for an understanding of the corresponding ICF processes. We show the possibility of the Darrieus-Landau instability in the laser ablation flow and discuss the specific features of the instability at the linear and nonlinear stages as compared to the combustion counterpart of this phenomenon. We consider the nonlinear stage of the Rayleigh-Taylor instability in the ICF and generation of ultra-high magnetic field by the instability, and show that proper understanding of vorticity production in the laser plasma and, hence, of the magnetic field generation requires concepts from combustion science.

  • 46.
    Bygdén, Olov
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Testpiloter i praktisk energieffektivisering: Visualisering och kommunikation2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete har utförts på Skellefteå Kommuns fastighetsavdelning under hösten 2012 och även under början på 2013. Fastighetsavdelningen är ansvariga för bl.a. driften hos Skellefteå Kommuns byggnader och därmed också ansvariga för att minska energianvändningen hos dessa. Till år 2016 har Skellefteå Kommun som mål att åstadkomma en energieffektivisering på 20 % jämfört med utgångsåret 2009. Detta projekt har utförts som en del av detta energieffektiviseringsarbete.

     Projektet omfattar två olika mätperioder, under den andra av dessa mätperioder installerades visualiseringsskärmar hos de två berörda objekt som utvalts till detta projekt. På visualiseringsskärmarna visades sedan den momentana energiförbrukningen för att brukarna skulle kunna hålla koll på om förbrukningen ökade eller minskade sett till den senaste veckan. Två informationsträffar, en för varje arbetsplats, hölls också för att informera om projektet samt att ge tips på tänkbara förändringar i arbetsmetoderna som skulle kunna medföra minskad energiförbrukning och därigenom ett positiv resultat.

    Resultatet av detta projekt blev en mängd mätdata som har sammanställts och analyserats för att slutligen resultera i ett utfall i form av att det ena objektet minskade sin energiförbrukning med 1,7 % och det andra objektet med hela 24,2 %.

    Slutsatsen har därmed blivit att visualisering samt kommunikation kan vara ett tänkbart alternativ till att åstadkomma en minskad energianvändning och motivera brukare av lokaler att bli engagerade och bidra själva.

  • 47.
    Bäckström, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimerad värmeleverans från Hedensbyverket2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Skellefteå Kraft AB has currently problems with the central district heating network in Skellefteå concerning low pressure difference between the delivering, hot, and returning, cold, pipeline. Cause of this low so called differential pressure, the customers heating requirements in these areas is not fulfilled in a satisfying way. The intent of this project has been, with the use of simulations, to clarify if a solution can be possible by connecting an increasing pressure pump to the district heating network. A pumpstation will be placed in such a way that it improves the ability to control the pressurization of the district heating pipelines and also makes it possible to distribute more heat from Hedensbyn, where the main production of district heat in Skellefteå takes place. Determine if the increase in pressure may result in an increase in electricity production, by lowering the temperature of the outgoing water.

    The result is this project shows that placing a pumpstation at Moröskolan is the most advantageous position. An increasing pressure pump at Moröskolan in Skellefteå would create more favourable conditions in order to control the pressure in the district heating network and maintain a minimum differential pressure. The simulations made shows that with a pumpstation, it is possible to distribute up to 20 MW more heat from the Hedensbyn. A pressure increase in the district heating network would currently allow for an increase in electricity distribution of approximately 4-5,5 GWh/year. Based on these results, the project concerning the pump is planned to begin during spring 2011.

  • 48.
    Bäckström, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Guilloux, Tom
    Fusing Kite and Tether into one Unit2017In: Airborne Wind Energy Conference 2017: Book of Abstracts / [ed] Moritz Diehl, Rachel Leuthold, Roland Schmehl, Freiburg, Germany: Albert-Ludwigs-Universität Freiburg; Delft University of Technology , 2017, p. 40-41Conference paper (Refereed)
  • 49.
    Bäfver, Linda
    et al.
    Pöyry SwedPower.
    Renström, Caroline
    Pöyry SwedPower.
    Fahlström, Johan
    Ragn-Sells.
    Enfält, Patrik
    EasyMining Sweden.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmén, Erik
    ENA Energi.
    Slambränsleblandningar: Förbränning och fosforutvinning2013Report (Other academic)
    Abstract [en]

    For sustainable phosphorus recycling, the phosphorus in sewage sludge needs to be recovered, as it is a major phosphorus-source. However, all sludge is not suitable for direct recycling on agricultural land, e.g. when the content of heavy metals is too high. To achieve an increased recycling of phosphorus from sewage sludge there is a need of research and development of alternative methods to return the phosphorus from sewage sludge to agricultural land.

    The aim of the project is to show that sewage sludge can be co-combusted with demolition wood in existing boilers, and that the ash can be processed for extraction of phosphorus, together with valuable by-products from the process. Further effects of the project will be the development of new knowledge about combustion with a high sludge to demolition wood ratio in a grate boiler (up to 45 % sludge with respect to wet mixture), which has not been studied in full-scale combustion earlier. The project's goal is to demonstrate mixing and combustion of fuel mixtures of sludge and demolition wood, and subsequent extraction of phosphorus from ash. The target groups for this work are energy companies, suppliers of grate boilers, municipalities, wastewater treatment plants and authorities.

    The project involves the mixing of sewage sludge and demolition wood, combustion-tests of the fuel mixtures and laboratory experiments on bottom ash and fly ash for phosphorus extraction using EasyMining Sweden's method for phosphorus extraction from ash. Extensive analyses have been carried out on fuel, bottom ash and fly ash, as well as thermodynamic equilibrium calculations on the formed compounds containing phosphorus.

    The experience of preparing sludge fuel mixtures shows that the mixtures should be prepared in the near future to when they are to be combusted, to avoid a composting process in the fuel. The project shows that it is possible to combust sludge fuel mixtures with an admixture of up to 45 % sludge relative wet fuel, in an existing grate boiler during one day. However, to combust sludge fuel mixtures over a longer period of time and at a higher load, modifications of the de-ashing system and the flue gas cleaning system are needed. The results indicate a reduced tendency of slagging on the fuel bed at the combustion of sludge mixtures. The analyses of the fly ash showed a trend towards less corrosive ash at combustion of sludge mixtures. The phosphorus content in the ash in this work was 3-4 %. For process economics and from the phosphorus extraction point, as high phosphorus content as possible in the ash is preferable. Higher phosphorus content can be accomplished by mixing sludge with a fuel with lower ash content than demolition wood, co-combustion with a fuel with higher phosphorus content than demolition wood, or by increasing the percentage of sewage sludge in the fuel mixture. Still, a higher proportion of sludge in the mixture would require a higher dry matter content of the sludge in order to get proper combustion conditions. It is primarily bottom ash that is suitable for phosphorus extraction using Easy Mining Sweden's method. If fly ash are to be used for phosphorus extraction, an optimization of the dissolution conditions is required, which was not included in this project. In this project, phosphorus is extracted as ammonium phosphate. The purity of ammonium phosphate is very high, which means that unwanted substances and heavy metals in sewage sludge will not be returned to contaminate fields.

  • 50.
    Carlborg, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Exposure studies of refractory materials for biomass gasification2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Gasification is a technology mostly used to convert fossil feedstock to syngas. Biomass could be used as a feedstock instead but that puts different demands on, among other things, the materials in these reactors.

    In this work, two candidate materials for the inner lining in biomass gasifiers (63 and 85 weight percent Al2O3) have been exposed to three synthetic ashes, K2CO3-CaCO3-SiO2, K2CO3-CaCO3 and K2CO3 at 1050°C in CO2 atmosphere for 7 days in a muffle furnace to reproduce analogous chemical attack that would occur in a real gasifier. Samples were investigated with SEM-EDX for morphological and compositional effects and with XRD for crystalline phases at chosen distances from the exposed surface.

    A heterogeneous melt that prevented deep penetration of alkali was produced when Si was present in the ash composition. In the absence of Si, it turned out that only K was affecting the materials. K attacked the matrix and transported into the material and attacking grains. For the material containing more alumina potassium was found in continuously decreasing amounts down to 7-8 mm from the exposed surface. The other material showed a distinct border between affected and pristine matrix about 5 mm from the exposed surface. The affected part seemed to have been filled out and signs of expansion could be seen. The XRD analysis of the pristine and exposed refractories revealed significant differences. In the exposed ceramics the new phases; Leucite, Kalsilite, Kaliophilite, K(2-x)Al(2-x)SixO4 and Wollastonite were observed.

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