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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.

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  • 2.
    Abrahamsson, Max
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Elbussar i Örnsköldsvik: En analys över vad som krävs för att elektrifiera bussarna i tätortstrafiken i Örnsköldsvik.2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For Sweden to achieve its environmental goals by 2045, municipalities need to reducegreenhouse gas emissions, especially from from the transport sector. Recentmeasurements in Örnsköldsvik have shown poor quality air in the built-up environment.Buses are the vehicle classes that emit, proportionally the most carbon dioxide equivalentgases. The intention is to replace the current city buses with electric vehicles to take asignificant step on the road to zero emissions.When electric buses are planned for a city traffic implementation, you must first establishwhat kind of electric buses you want to use. In Örnsköldsvik, the most relevant alternativestoday are either depot-charged or additional-charged buses.Which of the bus types that the municipality chooses to implement will affect themdifferently. If they choose depot-charged buses, the vehicles will be more expensive, but itwill not be necessary to add as much infrastructure and the circulation plan will not be asaffected as in the other case. In addition, some of the lines are too long to run all day, atsome point during the day a depot-charged bus must be run empty back to the depot to bereplaced by a charged bus. If additional-charging is chosen, the infrastructure will be moreexpensive (though fixed infrastructure has a low total cost compared to the cost of thevehicles as these have a longer depreciation period) and the circulation plan will need somechanges so that the buses have time to charge for a few minutes at the end stops.With current electric bus technology, electric buses should work in Örnsköldsvik’s urbanarea. Most with depot charging, some lines may need additional charging. Minimumrecommendations are made for the depot size, location and electric effect needed. Also,recommendation of piloting with 6 busses rather than taking a “Big bang” approach toimplementation to gain experience.

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  • 3.
    Adam, Nyström
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energideklarationsanalys: En inblick i energiläget i Umeå kommun2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the year 2018 the housing and service-sector accounted for 40% of the total use of energy in Sweden. Great adjustments and energy-technical actions are necessary to reduce the emissions from this sector. By analyzing the energy-use in buildings on a local scale through compilation of energy-declaration-data an overall look of the energy consumption is achieved. With this insight the work becomes easier to plan how the emissions from the housing and service-sector is supposed to be reduced with energy-efficient measures.

    The aim of this report is to investigate the energy-use in apartment buildings in Umeå kommun through analysis of energy-declaration-data. The goal is to present an overall look at the energy-use in the municipality and to present the measures that is needed to reduce the use of energy in apartment buildings.

    The work initiated by submitting a research certificate to Boverket to gain access to energy-declaration-data of buildings in the municipality. Five models were created by calculating the average value for different parameters in the data. The first model is based on the mean values for every apartment building in the data. The remaining four models were created with the average value for different parameters for apartment buildings with an energy-classification of D, E, F and G. Parameters such as heating system, ventilation system and the proposed energy-efficient measures were analyzed for each model. The models were simulated in an energy-program called BV2. The most frequent occurring energy-efficient measures in the data were applied to the models to calculate the potential reduction of energy consumption in the buildings. The energy use, carbon dioxide emissions and the primary-energy-value were calculated for each model after the energy-efficient measures were simulated.

    The distribution of energy-classification of the analyzed apartment buildings in Umeå kommun differs from the Swedish national compilation (Created by Boverket) according to the data. The number of buildings with an energy-classification of F and G is percental lower in Umeå compared to the national compilation. An average apartment building in Umeå has an energy-classification of E and uses 87.3 kWh/m2, year for heating purposes. The use of real estate electricity was calculated to an average of 16,7 kWh/m2, year. The most frequent occurring heating system in the data was district heating and the most frequent ventilation system was FTX. An apartment building in Umeå emits 6,43 kg CO2-e/m2, year on average. By analyzing the data and through calculations the result showed that by adjusting the heating system a yearly saving corresponding to 2 – 4% could be achieved. By installing water saving equipment in the apartments a potential saving corresponding to 3 – 8% could be achieved.

    Existing buildings should be renovated with application of energy-efficient engineering techniques in the same pace as new buildings are built. To reach carbon neutrality to the year 2040 a lot must be done to the existing building stock. Through compilation of energy-declaration-data and analysis an insight of the energy related problems could be located and improved.

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  • 4.
    Agelund, Anton
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Värmelagring i fjärrvärmesystem: Utredning hur en ackumulatortank kan påverka Arvidsjaur Energi2024Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this study, the possibilities of heat storage through an accumulator tank are examined to make the production at Arvidsjaur Energi and the district heating system more efficient. The purpose of the project is to evaluate the potential of heat storage and estimate the resulting savings. The goal is to deliver a report that Arvidsjaur Energi can use as a basis for assessments whether an installation would be advantageous or not.

    The method that is used in the project is to dimension the accumulator tank based on two different scenarios. Firstly, by smoothing out the operation on the base plant, and secondly, by reducing the use of expensive peak loads. By examining deviations and variations in operation on an hourly basis from previous times, the energy content that the accumulator must be able to store to even out the operation was calculated. In order to reduce the use of peak loads, days that could be accumulated were examined, allowing the base load to recharge the tank after it has been emptied. Based on these two different scenarios, two suitable dimensions could be determined, and calculations could then be made regarding the impact this would result in.

    An accumulator tank of 250 m3 was estimated to smooth out the operation approximately 97% of the time, while a 700 m3 tank would be required to reduce the use of peak loads. Concrete savings from smoothing out the operation turned out to be very difficult to predict and calculate since it primarily reduces wear and tear, but during peak power demand, approximately 1387 MWh would be accumulated. Since the tank is charged during the times when the heat demand decreases, a similar amount would thus recharge the tank, resulting in a significantly smoother operation compared to if no accumulator tank were present. The annual savings from reduced peak load usage turned out to be 286 MWh for the pellet boiler and 30,1 MWh for the oil boiler. This results in a total savings of 316 MWh annually. The total annual economic savings would in such a case be approximately 221 000 SEK. When any downtime occurs at the base plant, an accumulator tank could also delay the start-up of peak loads, resulting in savings but can also be seen as a safety measure. For an accumulator tank of 250 m3, the delay was estimated to be between 1-3 hours depending on the required power, and a 700 m3 tank would delay this start-up by approximately 3,5-10 hours.

  • 5.
    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
  • 6.
    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.

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    Analys av massapumps- och mixerarbete vid Metsä Board Sverige AB, Husums Fabriker
  • 7.
    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.

  • 8.
    Ahlqvist, Carl
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av uppvärmningsalternativ för Gammplatsen i Lycksele2024Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study focuses on evaluating various heating alternatives for Gammplatsen in Lycksele, aiming to reduce operational costs and enhance sustainability. The introduction highlights the dual challenge of maintaining comfort while decreasing energy consumption and enviromental impact. Due to the historical significance of the buildnings on Gammplatsen, renovation measures are exluded from this project.Eventually, Gammplatsen faces the need to upgrade from it’s current heating method based on direct electric heating.An energy assessment revealed an annual electricity demand of 113 MWh for maintaining the currently heated buildings, although the actual heating requirements were uncertain and had to be based on assumptions about the use of air-source heat pumps. Three main heating alternatives; district heating, ground source heat pump and pellet boiler – were evaluated.District heating was determined as economically unviable, both as a sole heating and in combination with currently installed air-source heat pumps. Ground source heat pump emerged as the most economically viable alternative, with a potential annual saving of approximately 50, 000 SEK. However, uncertainties existed regarding the feasibility of installing geothermal heat on-site, given its location in a water protection area. Pellet boiler yielded no significant savings and were not economically advantageous. The study’s conclusions underscore the importance of considering factors such as investment costs, energy savings, and enviromental impact when selecting heating alternatives. Despite uncertainties in the calculations, the study provides valuable insights for making informed decisions about future heating at Gammplatsen.

  • 9.
    Ahlsvik, Gustav
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av solcellsinstallation på en betongelementfabrik i norra Jämtland2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
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    Analys av solcellsinstallation på en betongelementfabrik i norra Jämtland
  • 10.
    Albin, Olskog
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Exploring the possibilities of Positive Energy Districts in a high latitude region: A case study from northern Sweden2024Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sustainable housing with energy efficient and flexible solutions is pivotal in lowering emissions and energy consumption. Positive Energy Districts (PEDs) is an initiative to design and enable areas within a city to have a surplus of renewable energy generation and net zero greenhouse gas (GHG) emissions. This study aims to identify the necessary parameters to run energy simulations for a district with the simulation software City Energy Analyst (CEA). Then to analyse the districts with the implementation of Energy Efficiency Measures (EEMs) and integration of local renewable energy production. Lastly, the scenarios has been analysed based on their potential of becoming a PED.

    The model for the simulation was calibrated based on data for U-values and energy demand from a building within the district located in Umeå, Sweden. Using the calibration, a model for a building district was created through scaling up the results and applying the building properties to all buildings. The first scenario was simulated with the same building properties as before a refurbishment project was initiated. The yearly average energy intensity for this scenario was simulated at 146.43 kWh/m2 of heated floor area. The same simulations were carried out for the remaining two scenarios: refurbishment and passive house. The energy intensity associated with these scenarios was 78.28 and 70.14 kWh/m2 of heated floor area respectively. The local renewable energy was also integrated into the scenarios and consisted of a total of 2410 m2 of photovoltaic cells with an energy production of 249 MWh. The conclusion from the results is that the EEMs mainly affect the heating demand of the district and the limited daytime hours during the winter solstice period affect the effectiveness of solar energy production which makes the feasibility of PEDs in the northern part of Sweden harder to achieve and proves that further measures is needed to achieve a PED.

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    Exploring the possibilities of Positive Energy Districts in a high latitude region - A case study from northern Sweden
  • 11.
    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.

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    Solar Heat in Industrial Processes
  • 12.
    Ali Haji, Kasim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy-efficient Industrial processes: An investigation in the power consumption, power number, thrust force and torque requirement on a rotating bed reactor2021Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    Rotating bed reactors are used throughout the process industry. They are usedboth in the chemical industry and other industrial sectors, such as pharmaceuticals and the textile industry in decolorization due to by-products or contaminants.SpinChem AB manufactures rotary bed reactors (RBRs) to perform chemical reactions between liquids and solids. The solid material consists of spherical particles0.1 mm - 1 mm in diameter that are packed between two cylindrical spaces in theRBR.

    The goal of this project work is to determine the power number, the axial force thatthe RBRn experiences, the torque requirement on the motor and power consumptionof the the RBR when a fully developed turbulent flow is achieved. The purpose ofthe work is to optimize the technology from the energy usage point of view, makethe product simple and easily accessible for chemical and industrial processes as acontribution to the development of sustainable society. In order to achieve the purpose and goal of the projects, Computational Fluid Dynamics (CFD) combined withexperimental models were used. Computation were made in COMSOL Multiphysicsfor two turbulence models. In it, the rotating machinery was used with moving meshtechnique for both the standard k−ε model and the SST k−ω turbulence models.The result is then compared with the empirical models.

    Investigation were done for two models of the rotating bed reactors (RBRs). Onemodel is called RBR S2 with relatively small size and RBR S14 which is a muchlarger version. For RBR S2 the experimental results turned out to be, an output ofpower number which is 3.4, torque requirement of 0.03 Nm, power consumption of3 W and a thrust force of 0.11 N. While the simulation results turned out to bean output of power number which is about 1.2, torque requirement of 0.013 Nm, apower consumption of 2 W and thrust force of 0.8 N. Similarly, the experimentalresult for RBR S14 was as follows. A power number of 0.53, torque requirement of0.41 Nm, power consumption of 6 W and a thrust force of 4.16 N. The simulationresults turned out to be, a power number of 0.34, torque requirement of 0,40 Nm,a power consumption of 4.14 W and thrust force of 3.61 N.

    With the help of the calculated power numbers, the power required to rotate theRBR can then be determined. Power number is determined when a fully developedturbulent flow is achieved. For RBRS2, a fully developed turbulent flow is achievedat Re = 2.8·104 and the angular velocity at that Reynolds number is about 830RPM. At that speed, the power is shown to be about 4 W for RBRS2. For RBRS14,a fully developed turbulent flow is achieved at Re = 1.5 · 105 and then the speed atthat Reynols number is about 83 RPM. The power need at that stage is shown tobe about 20 W.

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  • 13.
    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!

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  • 14.
    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.

  • 15.
    Almqvist, Jonna
    et al.
    SP Processum.
    Westin, Gunnar
    SP Processum.
    Öberg, Christian
    Umeå University.
    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.))
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  • 16.
    Almén, Ida
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Johansson, Elin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy supply system for a high-rise building in Germany: Optimization of a heating and cooling supply system made with plant simulations2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The building sector has great potential for energy savings since it is responsible for nearly a third of the global energy use. As oil, coal and natural gas continues to hold a big share of the energy mix it is important to work towards introducing more renewable energy alternatives. For an energy supply system, it is common to use a multi-energy system to increase efficiency. By increasing efficiency and the use of renewable energies, the total energy consumption can be lowered, and emissions can be reduced.

     

    The purpose of this thesis was to design a multi-energy supply system for a high-rise building in Germany with low emissions. This was executed by constructing a simplified design used as a reference, also referred to as option 1, and two other designs with different energy sources, called design 1 and design 2. The design layout was constructed in collaboration with Transsolar. Design 1 is using a compression chiller and is presented as three different variants, option 2, 3 and 4. The three options were created to evaluate the pros and cons of a larger cold water storage tank and sizing of the compression chiller. Design 2, option 5, is using an absorption chiller and this option was created to investigate the opportunity to use district heating. Simulations were made of the designs with the simulation tool TRNSYS and presented in graph form. Values provided from the simulations were then used to calculate emissions, investment costs and net present value over a period of 40 years. For the net present value, three different variants were presented. One without carbon costs taken into consideration, one with low carbon costs and one with high carbon costs. The result was evaluated, and comparisons were made to suggest the most sustainable option for the building.

     

    The result of design 1, which has a natural gas boiler for peak heating demand and a compression chiller as cold energy source, shows that the chiller produces a higher capacity compared to the installed value during the summer and a lower value during the winter. The norm capacity of the chiller in design 1 was 175 kW when combined with a larger cold water storage and 410 kW with no cold water storage. Comparison of those options showed that it is economical to install a cold water storage since the investment cost of the chiller is lowered. However, it also showed that a higher capacity of the chiller lowered the need for the gas boiler, because of the parallel heating and cooling characteristic of the chiller, which reduces emissions. Another option was made with a larger cold water storage implemented and an over dimensioned capacity of 340 kW for the chiller to reduce the gas needed for heating. For the option with the 175 kW compression chiller the gas boiler needed to supply 15% of the heating load of the building, while the option with the 340 kW compression chiller needed 3% of the buildings heating load to be provided by the gas boiler. This decrease in the gas boiler dependency reduced the emissions for heating from 52 ton/year to 41 ton/year, while still having comparable cost over time with low carbon costs and lower cost with high carbon costs. Therefore, the option with an over dimensioned chiller with an implemented big cold water storage is the favourable one, since it has the lowest emissions of the options of design 1 and is economically justifiable.

     

    Design 2 has one of lowest investment cost and the lowest emissions which was 61% lower than the reference design and 19% lower than design 1. With higher carbon costs option 5 is the cheapest, otherwise it is relatively similar to the other options. Hence, Design 2 is the system that is suggested to use for the building.

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    Energy supply system for a high-rise building in Germany
  • 17.
    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.

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  • 18.
    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.

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  • 19.
    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.

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  • 20.
    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.

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    Utredning av värmesystem i Boliden AB:s anläggning vid Tara-gruvan
  • 21.
    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.

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  • 22.
    Andersson, Oskar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Achieving energy efficiency and indoor climate: A comparison of varying control system and building envelope modification2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates the performance of varied control systems in a office building in the southern parts of Sweden. The control system is designed according to standard EN15232 with three levels of building automation and control systems with a multi-zone approach. Highest standard, class A, is a demand control system with VAV controlled by temperature and CO2-levels in each zone. The lighting in class A is controlled by user demand and dimmers with regard to daylight to meet lighting regulations. The ventilation in the middle system, class B, is VAV controlled by temperature and demand in a zone. lighting is only on when a zone is used but no opportunity to dimmer. The reference object, class C, uses constant air volume CAV based on Swedish regulation and has lighting as in class B. The building envelope is varied between an existing model with 70Às building standard, according to todayÀs standard, and passive house standard in Sweden. All simulations is evaluated through energy performance and indoor climate in terms of temperature, PMV, PPD and CO2-levels.

    Simulations showed that the class A system has the highest possibility to decrease the energy use compared to the other systems. The reduction in total energy use differs from about 9-27% compared to class C and about 29-34% in electric energy use. Simulations also showed that class A and B are more advantageous to apply in a passive house rather than in the existing building if the total energy is evaluated. With regards to electric energy use, the difference between the building envelopes is too small to state that any difference exists. Neither one of the systems corresponds to ”good” indoor climate in the critical zones, all three is between the range ”good” and ”acceptable” according to standard SE-EN15251. Class A and B show an overall improvement of PMV and PPD compared to class C system. The class B system is closest to fulfill a ”good” indoor climate, especially in the passive house model. Evaluation with respect to CO2-levels class A and C showed acceptable levels.

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  • 23.
    Andersson, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av verkningsgrad på Idbäcksverket panna 3 och tillhörande ångsystem: Kartläggning av förluster från inköpt bränsle till producerad el och fjärrvärme2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Vårt ständigt ökande energibehov tillsammans med att de fossila bränslelagren sannolikt inte räcker länge till gör att nya och koldioxidneutrala energikällor är viktigare än någonsin. Kraftvärme producerad med biomassa är ett utmärkt alternativ för produktion av grön el och fjärrvärme för att värma våra hem. Idbäckens kraftvärmeverk i centrala Nyköping förser ca 95% av Nyköping med fjärrvärme via kraftvärmepannan panna 3 och de fastbränsleeldade hetvattenpannorna panna 1 och 2. Panna 3 eldas primärt med returträflis och panna 1 och 2 med skogsbränslen.

    Under en längre tid har panna 3 visat ett lägre utbyte från inköpt bränsle till producerad energi. Förväntat utbyte eller totalverkningsgrad ligger kring 85% exklusive. rökgaskondensering för denna typ av anläggning, det verkliga utbytet ligger kring 76-81% de senaste åren. Detta projekt utfördes på uppdrag av Vattenfall BU Heat Sweden i ett försök att kartlägga vart förlusterna uppstår och bestämma det teoretiska energiutbytet mellan inköptbränsle och producerad energi. Därför har verkningsgrad för panna 3 och tillhörande ångsystem utvärderats för att säkerställa att förlusterna inte uppstår på anläggningen. Efter detta har förluster som inte kan förklaras med pannans och ångsystemets verkningsgrad försökt kartläggas. Dessa förluster utanför anläggningen har misstänkts bero på nedbrytning av bränslet under lagring vilket orsakar förluster av torrsubstans och därav brännbart material. 

    Pannans verkningsgrad har studerats under perioden Januari 2020 till och med Mars 2020 för att få en uppfattning om pannans prestanda den senaste tiden. Pannans verkningsgrad bestämdes till 88,2% under perioden, ångsystemets verkniningsgrad bestämdes till 95,3% under samma period. Kombinerat ger det en totalverkningsgrad på 84,0% vilket ligger i linje med det förväntade. Det teoretiska energiutbytet, vad kvoten mellan producerad energi och tillfört bränsle borde vara utifrån bestämda förluster ligger ca 2%-enheter högre på 86,1% under motsvarande period. Det saknas alltså flera %-enheter ner till det verkliga utbytet på 76-81%. Tre specifika driftfall har också studerats under låg, medel och hög last för att se när anläggningen är som mest effektiv. Utredningen visar att pannan och ångsystem är som mest effektiv vid hög last då trenden är att totalverkninggraden ökar med ökad last.

    De kvarstående förlusterna har inte kunnat kartläggas till fullo. En massbalans avseende aska in till, och ut från anläggningen har gjorts. En stor skillnad har noterats där aska ut från anläggningen är ca dubbelt så stor som den förväntade, vilket kan bero på att askhalten i inkommande bränsle är högre än vad bränsleanalyserna indikerar. Ett försök att kartlägga lagringsförluster har gjorts genom att jämföra inköpt bränsle med vad som faktiskt vägts in vid anläggningen där en viss skillnad har identifierats. Stora skillnader i enstaka bränsleleveranser gör det svårt att dra någon slutsats av detta men visar på osäkerheterna som finns kring bestämning av inköpt energi. En känslighetsanalys gjordes där det konstaterades att en felaktig bestämning av bränslets vikt utgör den känsligaste variabeln vid bestämning av det faktiska energiutbytet. En utökad provtagning har gjorts på ett bränsle som lagrats ca 7 veckor innan förbränning. Proverna visar på viss nedbrytning och försämring av bränslekvaliteten genom en ökad fukt- och askhalt samt att värmevärdet minskat under lagringen, vilket kan vara en del av orsaken till det låga utbytet de senaste åren.

    Fler provtagningar bör göras före och efter lagring av bränslet för att få ett större underlag till vad som händer med bränslet under lagring då detta inte är helt klarlagt för returträ. Detta tillsammans med att följa upp skillnaderna mellan köpt bränsle och invägt på Idbäcken så kan kanske det låga energiutbytet förklaras.

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  • 24.
    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. 

  • 25.
    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. 

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  • 26.
    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.

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  • 27.
    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.

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    Energisparåtgärder i samband med påbyggnad av nya bostäder
  • 28.
    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.

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    Våningspåbyggnad av miljonprogrammets flerbostadshus
  • 29.
    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.

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  • 30.
    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
  • 31.
    Andersson, Victor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Elektrifiering av personbilar på Tomtebo, Umeå: Electrifications of passenger cars at Tomtebo, Umeå2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the future, new fuels will be sought to minimize the carbon footprint on Earth. With electric vehicles becoming a growing trend there is an annual increase in hybrid and electric cars, even electrified buses have become more convenient. The new electric vehicles will then be a load on the electricity grid when recharging is required, sometimes during the sensitive hours of the day where other power requirements are greater. The purpose of this thesis was to gain a deeper understanding of how the Swedish electricity grid is structured and also answer the questions if the area named Tomtebo will be able to handle an electrification of passenger cars, and also what the power forecast will look like. An excel model, developed by Sweco, is used for the calculations and later on there is an evaluation of this model if it can be applied to smaller areas and if any improvements can be made towards it. The electric car load on the electricity grid is based on three possible scenarios referred from a report by Sweco and using the excel model to calculate the power requirement of the three scenarios with different traffic works on electricity. Scenario one corresponds to today's electrification degree on traffic work, scenario two corresponds to double electrification degree on traffic work and in scenario three, a full electrification as well as a new traffic hierarchy with more public transports will be used, according to the report by Sweco, resulting in less power requirements for traffic. In all three scenarios, it is assumed that the electric car will be charged at night with a charging power of 2.3 kW, this corresponds to charging directly from power outlet. Tomtebo is a residential area that is being expanded and is expected to grow in the coming years and the population there are mostly younger families, which gives the probability of investment of a fossil-free passenger car increase. In order to estimate the proportion of electric cars for the area, Statistics Sweden and Region facts have been used to estimate the amount of cars at Tomtebo. In Umeå there is a total of 1,400 electric cars and 95 of these were likely to be at Tomtebo. Out of this amount there is plugin hybrids, PHEV, and pure electric cars, BEV, which gave a distribution 75/25 percent according to data from national statistics. With a known number of cars, an itinerary was required which could be probable around twenty kilometers. In the Excel model, values were applied for scenario one, which gave the power requirement for the 95 cars a total of 18 kW per hour. With a grid that has a total power up to 3.7 MW per hour then the cars' power requirements are a minimal burden towards it, furthermore an equivalent result came from both scenarios two and three. With these three results came the conclusion that with the amount of cars available there today no major load was done on the electricity grid and thus a greater number of cars were required. Umeå aims to reach 200,000 inhabitants by the year of 2050, which would then give Tomtebo 12,000 residents and this would result in an estimated 6,100 cars there. Of these with today's distribution there would then be 200 electric cars but since this scenario is so far ahead in the future it was assumed that all vehicles in 2050 would be an electric car, which then leads to it being fully electrified at Tomtebo. The 6,100 electric cars power provided 6 MW of total power demand for today's electricity grid, which means that it won’t work in the future. To find the breaking point for how many electric cars the gird can handle it was assumed that all Tomtebo's cars today, corresponding to 3,780 cars, would be electric cars and by moving the charge schedule to early morning, when the demand was much lower, the result gave that the grid could handle about that many cars. What is important to understand is that the electricity grid does not have a maximum ceiling for demand, but it all works about equilibrium where one strives for a consistent power balance on all

    iv hours of the day. If the consumers need more power then the electricity companies transfer it but an under-dimensioned infrastructure can put a stop to this which might be the case in the future. When the question whether Tomtebo's electricity grid can handle the load, the answer is that a full electrification of Tomtebo is entirely possible but that future investments are something that should be reviewed. This result from the excel model using the parameters and assumptions reflects the reality. The difficult thing about using the model in my opinion is the estimation of car numbers where in a city like Umeå where there does not exist any cameras or registers of which car type is moving where, which it does on others places, such as Gothenburg and Stockholm. Furthermore, there are thoughts about the design of the model as well also the question of the depth of battery but this is left out here but can be read under the relevant section. What controls how quickly a changeover from fossil-fueled to non-fossil vehicles is the result of instruments where subsidies and taxation come into focus, then of course laws and regulations. What makes it so difficult to estimate what the future will look like in theory is that tomorrow can have a new law leaving only non-fossil vehicles.

  • 32.
    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.

  • 33.
    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.

  • 34.
    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.

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    Undersökning av smarta energilösningar för en planerad livsmedelsbutik
  • 35.
    Antlauf, Mathis
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Boulanger, Nicolas
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Berglund, Linn
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Oksman, Kristiina
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Andersson, Ove
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Thermal Conductivity of Cellulose Fibers in Different Size Scales and Densities2021In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 22, no 9, p. 3800-3809Article in journal (Refereed)
    Abstract [en]

    Considering the growing use of cellulose in various applications, knowledge and understanding of its physical properties become increasingly important. Thermal conductivity is a key property, but its variation with porosity and density is unknown, and it is not known if such a variation is affected by fiber size and temperature. Here, we determine the relationships by measurements of the thermal conductivity of cellulose fibers (CFs) and cellulose nanofibers (CNFs) derived from commercial birch pulp as a function of pressure and temperature. The results show that the thermal conductivity varies relatively weakly with density (ρsample = 1340–1560 kg m–3) and that its temperature dependence is independent of density, porosity, and fiber size for temperatures in the range 80–380 K. The universal temperature and density dependencies of the thermal conductivity of a random network of CNFs are described by a third-order polynomial function (SI-units): κCNF = (0.0787 + 2.73 × 10–3·T – 7.6749 × 10–6·T2 + 8.4637 × 10–9·T3)·(ρsample0)2, where ρ0 = 1340 kg m–3 and κCF = 1.065·κCNF. Despite a relatively high degree of crystallinity, both CF and CNF samples show amorphous-like thermal conductivity, that is, it increases with increasing temperature. This appears to be due to the nano-sized elementary fibrils of cellulose, which explains that the thermal conductivity of CNFs and CFs shows identical behavior and differs by only ca. 6%. The nano-sized fibrils effectively limit the phonon mean free path to a few nanometers for heat conduction across fibers, and it is only significantly longer for highly directed heat conduction along fibers. This feature of cellulose makes it easier to apply in applications that require low thermal conductivity combined with high strength; the weak density dependence of the thermal conductivity is a particularly useful property when the material is subjected to high loads. The results for thermal conductivity also suggest that the crystalline structures of cellulose remain stable up to at least 0.7 GPa.

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  • 36.
    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.

  • 37.
    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.

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  • 38.
    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
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  • 39.
    Azizi, Shoaib
    et al.
    Umeå University.
    Nair, Gireesh
    Umeå University.
    Olofsson, Thomas
    Umeå University.
    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.

  • 40.
    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.
    Rabiee, Ramtin
    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.
    Application of Internet of Things in academic buildings for space use efficiency using occupancy and booking data2020In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 186, article id 107355Article in journal (Refereed)
    Abstract [en]

    Environmental sustainability in academic buildings can be improved with management interventions such as improving space use efficiency supported by large data from the Internet of Things (IoT). Due to the potentials, the interest in the use of IoT tools for facility management is high among universities. However, empirical studies on this topic are scarce. To address the knowledge gap in this area, this study proposes and examines a process model with steps to measure space use and to improve space use efficiency by IoT tools in academic buildings. The applicability of the model is investigated in 8 lecture halls in a university building by using occupancy and booking data from IoT tools. Four space use indicators are developed to visualize the data and quantify space use, and based on them, the strategies and interventions for space use efficiency are proposed and discussed.

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  • 41.
    Azizi, Shoaib
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rabiee, Ramtin
    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.
    Effect of the positioning of multi-sensor devices on occupancy and indoor environmental monitoring in single-occupant officesManuscript (preprint) (Other academic)
  • 42.
    Azizi, Shoaib
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rabiee, Ramtin
    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.
    Effects of Positioning of Multi-Sensor Devices on Occupancy and Indoor Environmental Monitoring in Single-Occupant Offices2021In: Energies, E-ISSN 1996-1073, Vol. 14, no 19, article id 6296Article in journal (Refereed)
    Abstract [en]

    The advancements in sensor and communication technologies drive the rapid developments in the applications of occupancy and indoor environmental monitoring in buildings. Currently, the installation standards for sensors are scarce and the recommendations for sensor positionings are very general. However, inadequate sensor positioning might diminish the reliability of sensor data, which could have serious impacts on the intended applications such as the performance of demand-controlled HVAC systems and their energy use. Thus, there is a need to understand how sensor positioning may affect the sensor data, specifically when using multi-sensor devices in which several sensors are being bundled together. This study is based on the data collected from 18 multi-sensor devices installed in three single-occupant offices (six sensors in each office). Each multi-sensor device included sensors to measure passive infrared (PIR) radiation, temperature, CO2, humidity, and illuminance. The results show that the positions of PIR and CO2 sensors significantly affect the reliability of occupancy detection. The typical approach of positioning the sensors on the ceiling, in the middle of offices, may lead to relatively unreliable data. In this case, the PIR sensor in that position has only 60% accuracy of presence detection. Installing the sensors under office desks could increase the accuracy of presence detection to 84%. These two sensor positions are highlighted in sensor fusion analysis as they could reach the highest accuracy compared to other pairs of PIR sensors. Moreover, sensor positioning can affect various indoor environmental parameters, especially temperature and illuminance measurements.

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  • 43. Backman, Marjan Bozaghian
    et al.
    Strandberg, Anna
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Thyrel, Mikael
    Bergstrom, Dan
    Larsson, Sylvia H.
    Does Mechanical Screening of Contaminated Forest Fuels Improve Ash Chemistry for Thermal Conversion?2020In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 34, no 12, p. 16294-16301Article in journal (Refereed)
    Abstract [en]

    The effect of mechanical screening of severely contaminated forest fuel chips was investigated, focusing on main ash-forming elements and slagging tendency and other properties with relevance for thermal conversion. In this study, screening operations were performed according to practice on an industrial scale by combining a star screen and a supplementary windshifter in six different settings and combinations. Mechanical screening reduced the amount of ash and fine particles in the accept fraction. However, the mass losses for the different screening operations were substantial (20-50 wt %). Fuel analyses of the non-screened and the screened fuels showed that the most significant screening effect was a reduction of Si and Al, indicating an effective removal of sand and soil contaminations. However, the tested fuel's main ash-forming element's relative concentration did not indicate any improved combustion characteristics and ash-melting behavior. Samples of the accept fractions and non-screened material were combusted in a single-pellet thermogravimetric reactor, and the resulting ashes' morphology and elemental composition were analyzed by scanning electron microscopy-energy dispersive X-ray spectrometry and the crystalline phases by powder X-ray diffraction. Results from both these analyses confirmed that screening operations had no, or minor, effects on the fuels' ash chemistry and slagging tendencies, i.e., the fuels' proneness to ash melting was not improved. However, the reduction of ash and fine particles can reduce slagging and other operational problems in smaller and more sensitive combustion units.

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  • 44.
    Baigmohammadi, Mohammadreza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. Combustion and Turbulence Research Laboratory (CTL), Department of Aerospace Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Ave, Tehran, Iran.
    Tabejamaat, Sadegh
    Experimental study on the effect of external thermal pattern on the dynamics of methane-oxygen and methane-oxygen-carbon dioxide premixed flames in non-adiabatic meso-scale reactors2019In: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 137, p. 242-252Article in journal (Refereed)
    Abstract [en]

    In the current study, the effect of external thermal pattern on the dynamics and characteristics of methane oxygen and methane-oxygen-carbon dioxide premixed flames in non-adiabatic meso-scale cylindrical reactors is investigated experimentally. In this regard, two different external thermal patterns were imposed on the outer surface of the reactors. The results showed that imposing method/direction and also temperature level of the external thermal pattern have impressive effect on flame dynamics and chemiluminescence in the non-adiabatic meso-scale reactors. Also, it was shown that increasing the temperature level of the external thermal pattern could significantly extend the flame stability and its presence range in the meso-scale reactors, especially for the vitiated mixtures (methane-oxygen-carbon dioxide). Moreover, the results demonstrated that decreasing the inner diameter of a meso-scale reactor, which was subjected to an external thermal pattern, could increase the flame controllability and its presence range in the non-adiabatic meso-scale reactors.

  • 45.
    Baigmohammadi, Mohammadreza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Tabejamaat, Sadegh
    Javanbakht, Zeinab
    Numerical Study of Methane-Oxygen Premixed Flame Characteristics in Non-adiabatic Cylindrical Meso-Scale Reactors with the Backward-Facing Step2019In: Iranian Journal of Science and Technology, Transactions of Mechanical Engineering, ISSN 2228-6187, Vol. 43, p. 117-140Article in journal (Refereed)
    Abstract [en]

    In the present study, the effects of reactor diameter, inlet velocity, velocity profile, equivalence ratio (Phi, Ф), and outer wall convective and radiative heat transfer coefficients on flame characteristics in cylindrical non-adiabatic meso-scale reactors with the backward-facing step were investigated numerically. The results showed that these parameters could strongly affect the mole fraction of radical species within the flame zone. Also, it was shown that as compared to the reactor with 3 mm inner diameter, increasing the inlet velocity in the reactor with 5 mm inner diameter may lead to the opposite effect on the flame location. In addition, it was observed that the velocity profile could sensibly affect the flame location, temperature, and the species mole fractions in the meso-scale reactors. Moreover, it was demonstrated that the effect of equivalence ratio on the flame characteristics was more crucial for the reactors with smaller diameters. Furthermore, it was maintained that the outer wall convective and radiative heat transfer coefficients could cause the flame instability in the meso-scale reactors because of decreasing the mole fraction of important species such as O, H, and OH in the vicinity of the reactor inner wall.

  • 46.
    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.

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  • 47.
    Bergentz, Tobias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Identifying symptoms of fault in District Heating Substations: An investigation in how a predictive heat load software can help with fault detection2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    District heating delivers more than 70% of the energy used for heating and domestichot water in Swedish buildings. To stay competitive, district heating needs toreduce its losses and increase capabilities to utilise low grade heat. Finding faultysubstations is one way to allow reductions in supply temperatures in district heatingnetworks, which in turn can help reduce the losses. In this work three suggestedsymptoms of faults: abnormal quantization, drifting and anomalous values, are investigatedwith the help of hourly meter data of: heat load, volume flow, supplyand return temperatures from district heating substations. To identify abnormalquantization, a method is proposed based on Shannon’s entropy, where lower entropysuggests higher risk of abnormal quantization. The majority of the substationsidentified as having abnormal quantization with the proposed method has a meterresolution lower than the majority of the substations in the investigated districtheating network. This lower resolution is likely responsible for identifying thesesubstation, suggesting the method is limited by the meter resolution of the availabledata. To improve result from the method higher resolution and sampling frequencyis likely needed.For identifying drift and anomalous values two methods are proposed, one for eachsymptom. Both methods utilize a software for predicting hourly heat load, volumeflow, supply and return temperatures in individual district heating substations.The method suggested for identifying drift uses the mean value of each predictedand measured quantity during the investigated period. The mean of the prediction iscompared to the mean of the measured values and a large difference would suggestrisk of drift. However this method has not been evaluated due to difficulties infinding a suitable validation method.The proposed method for detecting anomalous values is based on finding anomalousresiduals when comparing the prediction from the prediction software to themeasured values. To find the anomalous residuals the method uses an anomalydetection algorithm called IsolationForest. The method produces rankable lists inwhich substations with risk of anomalies are ranked higher in the lists. Four differentlists where evaluated by an experts. For the two best preforming lists approximatelyhalf of the top 15 substations where classified to contain anomalies by the expertgroup. The proposed method for detecting anomalous values shows promising resultespecially considering how easily the method could be added to a district heatingnetwork. Future work will focus on reducing the number of false positives. Suggestionsfor lowering the false positive rate include, alternations or checks on theprediction models used.

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  • 48.
    Berggren, Daniel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Återladdning av bergvärmesystem och dess långsiktiga effekter: En metodik och beräkningsmodell2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Målet med denna studie är att ta fram en metodik och beräkningsmodell för att beräkna återladdningsmängd och dess effekter på ett bergvärmesystem som kan användas tillsammans med simuleringsverktyget för bergvärmesystem Earth Energy Designer (EED) och som kan hantera olika återladdningsmetoder. Syftet med studien är att automatisera och effektivisera beräkningen av optimal återladdning. 

    För att utföra detta skapades en beräkningsmall i Microsoft Excel. I mallen kan användaren importera effekter från den valda återladdningsmetoden, beroende på bergvärmesystemets värmebärartemperaturer. I de fall som återladdningeffekten är beroende av utomhustemperaturen kan även dessa importeras i mallen. Därefter, så kan användaren simulera bergvärmesystemet i EED där temperaturer beräknas. Dessa kan sedan importeras till beräkningsmallen och effekter beroende på de aktuella temperaturerna kan beräknas. Effekterna kan sedan bli exporterade till EED och bergvärmesystemet kan återigen simuleras och nya temperaturer uppstår. Denna process måste repeteras tills dess att konvergens uppnåtts och temperaturerna slutar ändras mellan simuleringarna. Den utvecklade beräkningsmodellen och metodiken har sedan tillämpats på en fallstudie där det projekterade bergvärmesystemet ska leverera värme till en förskola i Luleå kommun. Detta GSHP-system har 16 borrhål, dimensionerat för att möta förskolans värmebehov och därav är det väldimensionerat. På grund av implementeringen av återladdning så har antalet borrhål reducerats så att bergvärmesystemet blir underdimensionerat, effekterna av återladdning på detta system har utvärderats och jämförts med det väldimensionerade bergvärmesystemet. Fyra fall av återladdning har blivit implementerade. I samtliga fall har bergvärmesystemet återladdats med kylmedelkylare men återladdningseffekten och energin har varierat mellan de olika fallen. 

    Resultaten visade att genom återladdningen kan både temperaturen på värmebäraren i borrhålen och COP höjas. Detta leder till att energin som behöver tillföras värmepumpen minskar liksom driftkostnaden för densamma. Vid en ekonomisk analys för det väldimensionerade, underdimensionerade bergvärmesystemet utan återladdning samt de fallen där återladdning implementerats visade resultaten dock att den totala livscykelkostnaden blev större för de fallen med återladdning än de fallen utan. Detta beror på att både den totala drift och installationskostnaden för systemen blir större när återladdningen implementerats än när det inte görs. Detta trots att investeringskostnaden för borrhålen minskar när antalet borrhål minskar samt att energin som krävs till värmepumpen minskar när återladdning implementerats.

    Slutsatsen som kan dras av studien är att en beräkningsmodell och metodik för att beräkna återladdning och dess effekter på ett bergvärmesystem kunde skapas. Modellen och metodiken kan också användas tillsammans med EED för flera typer av återladdning men i denna studie har den enbart implementeras med en återladdningsmetod. Rörande effekterna av återladdning med den implementerade återladdningsmetoden på borrhålen, så visade resultatet att återladdning med kylmedelkylare i detta fall inte är ekonomiskt lönsamt och ska bara implementerats om det är något som krävs om det till exempel skulle vara begränsad yta för borrning av borrhål. Detta är dock något som måste beräknas i varje enskilt fall av återladdning.

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  • 49.
    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

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  • 50.
    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.

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