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  • 251.
    Sahl, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Varmhållning av flygplan - en ny tillämpning av fjärrvärme: Produktutveckling av klimataggregat för flygplan vid markservice.2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aviation industry today is responsible for 2 % of the fossil carbon dioxide emissions and has, as the first global industry, united around common goals for reducing its effect on climate change. The district heating industry faces tough challenges ahead considering the demand of its primary product is predicted to decrease in the longer run. Smart Climate Scandinavian AB’s idea of heating airplanes parked on ground with district heating unites the needs for both the aviation and district heating industry of reducing emissions and finding new areas of application respectively.

    The purpose of this thesis is to provide information for development of the next generation Smart Climate air climate unit control system and to study the consequences of changing from a traditional air climate unit to one from Smart Climate, with regard to energy efficiency, environmental impact, and operation cost.

    The thermal properties of an airplane of the type ATR72-500 where measured. The U-value was calculated to 2,0 W/(m2·K) and the heat capacity to 3,421 MJ/kg. An Excel application was programmed in Excel VBA to be used for product development. The application calculates the energy demand of an airplane based on settings such as outside temperature and the airplane’s thermal properties.

    The potential energy savings of introducing night time reduction, which is temporarily reducing the temperature in the airplane, is calculated to about 30 % of the initial energy demand.

    A consequence analysis of changing from a traditional electricity based air climate unit to one based on district heating with the proposed night time reduction was performed. The analysis was limited to the airplane as the system boundary and hence does not include energy losses which both systems have. The night time reduction is not implemented in traditional air climate units and hence the demand in energy is calculated to decrease from 25000 kWh to 15500 kWh per year for an ATR72-500. Changing energy source from electricity to district heating results in a reduced emission of CO2e of somewhere between 9000 and 22000 kg per year. How big the saving in operation cost will be depends on the energy prices for electricity and district heating.

    An introduction of night time reduction is recommended in the next generation control system of Smart Climate’s air climate unit since it evidently comes with great energy savings. It is also proposed that the next generation is wired up online on the internet. This will facilitate future setting adjustments, data gathering and product development. Also validated during the study is that the technique of regulating the temperature of inlet air by measuring the cabin temperature is more reliable than the traditional technique of using the outside temperature.

    It is suggested for future studies to include energy transport losses and hence should focus on one airport with well-defined system boundaries. A suggestion is using the same boundary as the energy meters of the airport. Optimizing glycol/water flow and dimensioning of pipes, valves and pumps are interesting issues to investigate.

    A reduced electricity demand will decrease the needed capacity of the transformer station and could give reason for considering heating airplanes with district heating. Perhaps the most important consequence of replacing electricity with district heating is that primary energy can be used where it is needed. 

  • 252.
    Salander, Alexander
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energianalys av lägenhetshuset ”NCC folkboende”: En undersökning utförd med simuleringsprogrammet ”IDA Indoor Climate and Energy” och litteraturstudie2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    On behalf of Ramböll Buildings in Umeå this thesis has been performed during the spring semester of 2016. The purpose of the thesis was to investigate the possibility to lower the energy use down to 25 % of BBRs demand in apartment buildings. The building that has been used during the thesis is a concept house from NCC, also called NCC folkboende. The goal was to construct an IDA ICE-model over the building to examine different energy efficiency measures. Also, literature studies on other energy use have been done. The results show that even whit extreme measures it is hard to achieve a reduction of the energy use down to 25 % of BBRs demand. To lower the energy use only through improving the building itself is hard when newer buildings already use little energy. To supply energy to the building for example with solar cells are a good way to reduce the total energy use. 

  • 253.
    Sandström, Karin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bildning och sulfatering av fluorider i aska vid förbränning2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Combustion of waste in combined heat- and power plants are the primary solution for waste that is not recycled or reused in Sweden today. Municipal solid waste contains a wide range of ash-forming elements, which could lead to operational problems in the boiler that limits the plant’s efficiency. Different elements are found in different waste fractions, and some can cause severe corrosion problems in heat transferring parts of the boiler. The heat and power industry has been aware of the problems associated with chlorine for a long time, as this is an element that is known to contribute to corrosion. New materials mean that high levels of previously unknown elements for the heat and power industry enters the plants. One of these elements is fluorine which is found in fluoropolymers which are chemically inert plastics. Fluoropolymers are found in sports and outdoor clothing, as well as cookware and a number of other products, and the production of these type of materials is expected to increase significantly over the next few years.

     

    The purpose of this work was to investigate the distribution of fluorine by addition of sodium fluoride (NaF) to pure wood pellets. This was done through thermodynamic calculations and bench scale combustion tests. Four fuel mixtures were tested, one containing NaF alone, one containing sodium chloride (NaCl), one containing both NaF and NaCl and one containing NaF, NaCl and sulfur. During combustion tests, the concentrations of HCl, HF and SO2 in the flue gases were logged. Analysis of bottom ash, deposits and particles in the flue gas was performed with SEM/EDS and XRD-analysis after each combustion test. The results showed that fluorine appears to be more likely than chlorine to stay in the bottom ash. This was confirmed by thermodynamic equilibrium calculations and by combustion tests. Furthermore, the thermodynamic equilibrium calculations showed that a large share of fluorine should end up in the flue gas as HF. Furthermore, the combustion tests showed that sulfation of fluorine salts occurs at lower levels of sulfur than sulfation of chlorine salts. In practice, this means that if the levels of fluorine-rich fuel increases in a waste incineration plant, the proportion of HF in the flue gases should increase and that some of the sulfur in the fuel mixture will be used for sulfation of fluorine salts if they are formed. The distribution of fluorine if fluorinated plastics are added to the fuel is not investigated in this work and something that should be investigated in the future.

  • 254.
    Sedin, Marcus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    VVS-projekteringsförslag på LSS-bostad2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I Sverige finns det cirka 4,5 miljoner bostäder och den siffran stiger i lika snabb takt med den ökande befolkningen. Riksdagen har beslutat att energianvändningen ska minska i två etapper utifrån EU:s direktiv att uppnå så kallade näranollenergibyggnader.Här beskrivs vilka parametrar som utgör en byggnads energiprestanda och hur man sänker energianvändningen i bostäder genom VVS-projektering. Framförallt hur man kan nå detta utifrån den ekonomiska aspekten. Vilka regler och krav måste följas för att inte påverka människans hälsa.Projektet innefattar teoretiska sammanställningar av VVS komponenter som är grunden till genomförandet. Den tänkta bostaden byggdes upp och simulerades i simuleringsprogrammet IDA ICE för att plocka fram viktig information till VVS-projekteringen.Resultatet visar att en bergvärmepump är en fördelaktig värmekälla ekonomiskt men framförallt energimässigt. Ventilationssystemet klarade att upprätthålla ett gott inomhusklimat utan att bryta mot några föreskrifter.

  • 255.
    Sehlstedt, Kim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av nya styrsätt för Hedensbyverket2017Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    The objective of the present thesis was to investigate alternative ways of controlling boiler 2 at Hedenbyverket with the target to smoothen the combustion process and thereby increase the maximum production. The boiler capacity is limited by the maximum flow of flue gas fan and the control mode of the boiler entails in fluctuations, which lowers the production even more. Operation test campaigns showed that the fluctuations can be derived to two different phenomena in the boiler. Low frequent fluctuations occur due to the fuel feed system attempting to control the vapor pressure. There are also fluctuations with higher frequency which are caused by variations in the fuel flow that is being fed into boiler. Two different measures were proposed, one that eliminates the low frequent fluctuations and one measure that reduces the high frequent fluctuations. With the help of some assumptions, new values for boiler efficiency and resulting maximum production was calculated for each measure. An optimization model was used to predict the production of all heat generators connected to the district heating system and the economic effect of each measure was estimated. The results showed that by smoothening the high frequent fluctuations a profit higher than 100 000 SEK could be made due to higher electricity production for boiler 2 at Hedensbyverket and reduced heat production at other facilities. However, to achieve the highest amount of savings it is recommended to implement both measures. A future study is recommended to investigate whether an investment in a bigger flue gas fan would be profitable. 

  • 256. Sepman, Alexey
    et al.
    Jansson, Kjell
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wiinikka, Henrik
    Combustion characterization of five recyclable metal fuels2018Conference paper (Refereed)
  • 257. Sepman, Alexey
    et al.
    Ögren, Yngve
    Qu, Zhechao
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Wiinikka, Henrik
    Schmidt, Florian M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University.
    Real-time in situ multi-parameter TDLAS sensing in the reactor core of an entrained-flow biomass gasifier2017In: Proceedings of the Combustion Institute, ISSN 1540-7489, E-ISSN 1873-2704, Vol. 36, no 3, p. 4541-4548Article in journal (Refereed)
    Abstract [en]

    Tunable diode laser absorption spectroscopy (TDLAS) was used to measure several important process parameters at two different locations inside the reactor of an atmospheric, air-blown 0.1 MWth biomass gasifier. Direct TDLAS at 2298 nm was employed for carbon monoxide (CO) and water vapor (H2O), calibration-free scanned wavelength modulation spectroscopy at 1398 nm for H2O and gas temperature, and direct TDLAS at 770 nm for gaseous elemental potassium, K(g), under optically thick conditions. These constitute the first in situ measurements of K(g) and temperature in a reactor core and in biomass gasification, respectively. In addition, soot volume fractions were determined at all TDLAS wavelengths, and employing fixed-wavelength laser extinction at 639 nm. Issues concerning the determination of the actual optical path length, as well as temperature and species non-uniformities along the line-of-sight are addressed. During a 2-day measurement campaign, peat and stem wood powder were first combusted at an air equivalence ratio (lambda) of 1.2 and then gasified at lambdas of 0.7, 0.6, 0.5, 0.4 and 0.35. Compared to uncorrected thermocouple measurements in the gas stream, actual average temperatures in the reactor core were significantly higher. The CO concentrations at the lower optical access port were comparable to those obtained by gas chromatography at the exhaust. In gasification mode, similar H2O values were obtained by the two different TDLAS instruments. The measured K(g) concentrations were compared to equilibrium calculations. Overall, the reaction time was found to be faster for peat than for stem wood. All sensors showed good performance even in the presence of high soot concentrations, and real-time detection was useful in resolving fast, transient behaviors, such as changes in stoichiometry. Practical implications of in-situ TDLAS monitoring on the understanding and control of gasification processes are discussed.

  • 258.
    Shanmugam, Kavitha
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gadhamshetty, Venkataramana
    Yadav, Pooja
    Athanassiadis, Dimitris
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Upadhyayula, Venkata K.K.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Advanced High-Strength Steel and Carbon Fiber Reinforced Polymer Composite Body in White for Passenger Cars: Environmental Performance and Sustainable Return on Investment under Different Propulsion Modes2019In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 7, no 5, p. 4951-4963Article in journal (Refereed)
    Abstract [en]

    Vehicle lightweighting strategies must deliver sustainable returns to customers and society. This work evaluates the sustainable return on investment (SROI) of lightweighted advanced high strength steel (AHSS) and carbon fiber reinforced polymer (CFRP)-intensive multimaterial bodies in white (BIWs) for automobiles. The SROI depends on the lightweighted BIW's manufacturing cost and the difference in sustainable cost between a baseline (mild steel) BIW and the lightweighted alternative. The sustainable cost is the sum of the customer's lifetime fuel (or electricity) costs and the costs of environmental externalities. A cradle-to-grave life cycle assessment (LCA) was conducted to quantify the environmental impacts of CFRP and AHSS BIWs in gasoline-fueled cars, bioethanol (E85)-fueled cars, and battery electric vehicles (BEVs) driven for a lifetime distance of 200 000 km. For cars fueled with gasoline- or corn-based bioethanol, the CFRP BIW yielded the lowest SROI; the AHSS BIW performed best for BEVs and cars fueled with wood bioethanol. However, the commercial availability of recycled carbon fiber should increase the SROI of the CFRP BIW in the future. Additionally, the SROI of CFRP BIWs is maximized when carbon fiber production is done using energy from a low carbon-intensity electric grid or decentralized sources such as waste-to-energy incineration plants.

  • 259.
    Sjulgård, Mikael
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Riktlinjer för modellering av reaktorkylpumpar i TRACE2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Examensarbetet är utfört vid Ringhals AB och riktar in sig på reaktorkylpumparna på reaktor tre vid Ringhals kärnkraftverk (R3). R3an är en tryckvattenreaktor och reaktorkylpumparna är vertikala enstegs centrifugalpumpar som tillverkats av Westinghouse.

    Bakgrunden till detta examensarbete är att Vattenfall AB vill öka kunskapen inom modellering av LOCA (Loss-of-coolant Accident) och har startat ett projekt för modelleringen av detta i den termohydrauliska koden TRACE. En viktig del i modelleringen av LOCA är hur reaktorkylpumparna beter sig när dom får hantera ett tvåfasflöde och då främst hur försvagad deras pumpförmåga blir.

    För att kunna göra en korrekt modell av pumparna i TRACE behövs pumpkurvor för samtliga pumpregimer för både enfasflöde och fullt försvagat tvåfasflöde samt en kurva för hur pumpen reagerar på olika ånghalter. För de pumpar som finns på R3 finns bara kurvor för fyra pumpregimer för enfasflöde, så i dagsläget är det svårt att göra korrekta analyser av pumpförmågan.

    Syftet med arbetet är att få fördjupad förståelse hur reaktorkylpumparna beter sig vid ett tvåfasflöde och hur detta på bästa sätt kan modelleras för R3s pumpar och målet är att analysera och ge modelleringsförslag på bästa sättet att modellera reaktorkylpumparna i samband med tvåfasflöde.

    Examensarbetet har delats upp i två delar. En litteraturstudie för att utreda vilka pumpdata som skall användas för att på bästa sätt efterlikna pumparna på R3 och vad som gör att pumparna försvagas. Den andra delen består utav modelleringar i TRACE för att se hur olika pumpkurvor och andra förutsättningar påverkar pumpförsvagningen och hur väl detta stämmer överens med tester som finns gjorda.

    Vid jämförelse av pumpkurvorna för enfasflöde och den specifika hastigheten var det KWU-pumpen som bäst stämde överens med pumparna på R3an. Med antagandet att pumpar med liknande enfaskarakteristik och specifik hastighet uppvisar liknande tvåfaskarakteristik så skulle data från KWU-pumpen vara det bästa för att modellera R3ans pumpar, följt av Westinghouse pumpar vars pumpdata finns inbyggt i TRACE.

    Vid lågt systemtryck, som det blir vid en LOCA, kommer pumpen antagligen att försvagas betydligt mer än vad som både KWU och Westinghouses pumpkurvor gör. Så för att inte överskatta pumpförmågan kan en lösning vara att antingen använda de inbyggda Semiscale kurvorna eller att man använder en kombination av Westinghouse eller KWUs pumpkurvor tillsammans med försvagningskurvan från Semiscale.

  • 260.
    Sjöberg, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Framställning av energisignaturer för byggnader i Umeå kommun2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    För att kunna nå de energimål som sätts upp inför framtiden måste Umeå kommun aktivt jobba för att ständigt förbättra nuvarande energiläge. För att uppnå målet ingår Umeå kommun i ett EU-projekt som heter E-lighthouse, där de jobbar mot energieffektivisering.

    Syftet är att göra en kartläggning av energisignaturer i Umeå kommuns västra driftområde. För att i det projektet analysera vad som kan hjälpa Umeå kommuns fastighetsavdelning när det kommer till optimering av drift och energianvändning i deras byggnader.

    En litteraturstudie har genomförts för att skapa grundläggande kunskap inom området av energisignaturer. För att efter kartläggning analysera teorier och aspekter som kommit fram. Detta ska resultera i något som kan vara av intresse för Umeå kommuns fastighetsavdelning.

    Resultatet visade att i framtagningen av energisignaturer kan det vara bra att dela upp dag och natt värden. I syfte av att få en överblick över hur en byggnad beter sig värmetekniskt vid olika tidpunkter på dygnet.

    I slutet av projektet gjordes en framtagning av ett intervall som visar var energianvändningen bör ligga för en byggnad i en energisignatur. Detta kan vara ett verktyg att använda i vidare energioptimering.

  • 261.
    Sjödin, Isak
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Cool Roof Coatings on Industrial Buildings: An Energy Study of Reflective Coatings2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To evaluate the effect of cool roof coatings containing Expancel® thermoplastic microspheres on industrial buildings, a warehouse was built-up in the computer simulation software IDA-ICE. The warehouse was modelled in line with ASHRAE 90.1. 2004 ”Energy Standard for Buildings Except Low-Rise Residential Buildings”. Four different cases were set up where the coating of the roof was the only variable. Two coatings containing Expancel® microspheres - one white and one red coating were compared to the same white coating without Expancel® microspheres and the ”base case” where there is no coating at all. The same circumstances were also implemented in a practical laboratory test using a model warehouse with a detachable roof. Four interchangeable roofs with different roof coatings constitute the various cases in the laboratory tests. A ”sun” consisting of statically mounted IR light bulbs were constructed, as well as a cooling system to measure the difference in cooling effect (maintaining a constant indoor temperature) between the different cases as a result of the change in insolation.

    The results of the computational simulations show that for a warehouse placed in Houston, Texas about 50 MWh in combined heating and cooling energy can be saved yearly between the best and the worst case, a reduction of 6.2%. Changing the geographic placement of the warehouse to Tepic, Mexico the corresponding savings were determined to 83 MWh or 13.5%.

    A way of determining the yearly savings in heating and cooling amount for the warehouse with a generic roof coating, only knowing the SRI value of the coating, was developed. It was determined that for every unit-increment of the SRI value the yearly savings for the warehouse placed in Houston, Texas were 718 kWh and 0.1%. The corresponding savings for the warehouse placed in Tepic, Mexico were determined to be 1252 kWh and 0.22%.

    The laboratory tests showed that the indoor temperature of the model warehouse decreased by close to 16°C between the best and the worst case.

  • 262.
    Sjölander, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Prediction of ignition limits with respect to fuel fraction of inert gases.: Evaluation of cost effective CFD-method using cold flow simulations2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Improving fuel flexibility for gas turbines is one advantageous property on the market. It may lead to increased feasibility by potential customers and thereby give increased competiveness for production and retail companies of gas turbines such as Siemens Industrial Turbomachinery in Finspång. For this reason among others SIT assigned Anton Berg to perform several ignition tests at SIT’s atmospheric combustion rig (ACR) as his master thesis project. In the ACR he tested the limits for how high amounts of inert gases (N2 and CO2) that the rig, prepared with the 3rd generation DLE-burner operative in both the SGT-700 and SGT-800 engine, could ignite on (Berg, 2012).

    Research made by Abdel-Gay and Bradley already in 1985 summarized methane and propane combustion articles showing that a Karlovitz number (Chemical time scale/Turbulent time scale) of 1.5 could be used as a quenching limit for turbulent combustion (Abdel-Gayed & Bradley, 1985). Furthermore in 2010 Shy et al. showed that the Karlovitz number showed good correlation to ignition transition from a flamelet to distributed regime (Shy, et al., 2010). They also showed that this ignition transition affected the ignition probability significantly.

    Based on the results of these studies among others a CFD concept predicting ignition probability from cold flow simulations were created and tested in several applications at Cambridge University (Soworka, et al., 2014) (Neophytou, et al., 2012). With Berg’s ignition tests as reference results and a draft for a cost effective ignition prediction model this thesis where started.

    With the objectives of evaluating the ignition prediction against Berg’s results and at the same time analyze if there would be any better suited igniter spot 15 cold flow simulations on the ACR burner and combustor geometry were conducted. Boundary conditions according to selected tests were chosen with fuels composition ranging from pure methane/propane to fractions of 40/60 mole% CO2 and 50/75 mole% N2.

    By evaluating the average Karlovitz number in spherical ignition volumes around the igniter position successful ignition could be predicted if the Karlovitz number were below 1.5. The results showed promising tendencies but no straightforward prediction could be concluded from the evaluated approach. A conclusion regarding that the turbulence model probably didn’t predict mixing good enough was made which implied that no improved igniter position could be recommended. However by development of the approach by using a more accurate turbulence model as LES for example may improve the mixing and confirm the good prediction tendencies found. Possibilities for significantly improved ignition limits were also showed for 3-19% increase in equivalence ratio around the vicinity of the igniter.

  • 263.
    Sjöström, Katarina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Miljöpåverkan från fjärrkyla: en analys av Umeå fjärrkyla med fokus på primärenergianvändning och växthusgasutsläpp2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Umeå Energi aims to be renewable in everything they do in 2018. As part of this work, they want to know the environmental impact of their product district cooling.

    In this report, the environmental impact from Umeå district cooling has been calculated by developing the key numbers primary energy use per delivered cooling energy and greenhouse gases in carbon dioxide equivalents per delivered cooling energy. The environmental assessment has been based primarily on reports from government authorities and trade associations. Data for calculations have been collected from statistics and from plant reports of Umeå Energi.

    The primary energy use of district cooling has been calculated to 0,94 kWh per kWh delivered cooling energy and the greenhouse gas emissions to 63 g CO2 per kWh delivered cooling energy. A factor of uncertainty in the calculation is the estimated electricity use for cooling. The methodical choice that affects the results most is the allocation of the heat pump's electricity use between heat and cold.

    A comparison between Umeå district cooling and individual cooling with a vapor-compression chiller (VCC) has been done. The comparison shows that district cooling uses less primary energy than VCC with a coefficient of performance lower than 1,6. An electric cooler with a coefficient of performance lower than 3,3 will cause higher emissions of greenhouse gases than district cooling.

    Extended measurement of electricity use for cooling and development of common guidelines for environmental evaluation of energy production are recommended for future work.

  • 264.
    Skarin, Jakob
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bottenutskov i vattenkraftsdammar: Möjligheter, risker och strömningsmekaniska utmaningar2017Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    The dam in a hydroelectric power station serves to divert water to the station’s turbines, and to allow for energy storage and power balancing. When the flow in the river is high or when the energy producing parts of the facility are inoperative, water needs to be discharged from the reservoir. This is done with outlets. In Sweden, most outlets are near the surface, but in some cases bottom outlets are used. Commonly, these outlets were used during the construction of the dam to divert water and have been unused since then. The purpose of this project was to investigate the possibility to recommission bottom outlets in hydropower dams where they are existent but not in use, to increase dam safety.

    The first part of the report contains a summary of theoretical problems with bottom outlets, based on industry experiences and literature. The second part presents the results of a case study of a specific facility, Båtfors hydroelectric power station. Calculations have been made, both by hand and with computational fluid dynamics, to identify possibilities and problems.

    Several theoretical problems have been identified, including: erosion, cavitation, insufficient aeration, debris, and problems with closing the outlet gates.

    The current discharge capacity for Båtfors power station was estimated by hand to slightly over 900 m3/s at the normal reservoir water level, which is consistent with the documentation of the facility. For each of the two bottom outlets, the discharge capacity was calculated to around 225 m3/s with the gate fully open (2.4 m). The values calculated by hand were compared to simulated ones for different gate openings and a certain difference (around 30–40 %) was noted. No simulation results could be obtained with the gate fully opened due to convergence issues.

    The movement of air in the bottom outlets of Båtfors were studied by simulations. When the gate was opened to a small degree, 0.4 and 0.8 m, air could be supplied from the downstream opening of the outlet conduit which was impossible when the gate was opened 1.2 m. This may cause problems if sufficient aeration cannot be achieved through openings in the outlet ceiling.

    The risk of cavitation in Båtfors was investigated by comparing the simulated minimum pressure in the outlet with the saturation pressure of water at 20 °C. It was determined that cavitation likely won’t be an issue at this facility, which conforms with literature.

    It was concluded that several issues can occur when using bottom outlets, but also that several opportunities exist. These outlets can be used to increase the discharge capacity and drawdown range of the facility, as emergency outlets, and to enable lowering of the reservoir water level. The lattermost can furthermore not be achieved by other means.

  • 265.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ash chemistry and fuel design focusing on combustion of phosphorus-rich biomass2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Biomass is increasingly used as a feedstock in global energy production. This may present operational challenges in energy conversion processes which are related to the inorganic content of these biomasses. As a larger variety of biomass is used the need for a basic understanding of ash transformation reactions becomes increasingly important. This is not only to reduce operational problems but also to facilitate the use of ash as a nutrient source for new biomass production.

    Ash transformation reactions were examined in the present work using the Lewis acid-base concept. The model presented in Paper I was further extended and discussed, including the definition of tertiary ash transformation reactions as reaction steps where negatively charged molecular ions, Lewis bases, other than hydroxides are present in the reactants. The effect of such reactions for bonding of various metal ions, Lewis acids, were discussed. It was found that the formation of various phosphates through secondary and tertiary ash transformation reactions is important for the behaviour of biomass ash in combustion. The suggested model was supported by findings in Papers II-VIII.

    The experimental findings in Papers II-VIII were discussed in terms of ash transformation reactions. The fuel design choices made to investigate the effect of phosphorus in particular on ash transformation reactions were high-lighted. Addition of phosphoric acid to woody-type and agricultural biomasses showed that phosphate formation has a large influence on the speciation of Si, S, and Cl. Co-combustion of a problematic agricultural residue with other biomasses showed that the relation between phosphorus, alkali and alkaline earth metal content is important. Co-combustion of biosolids with wheat straw was shown to greatly improve the combustion properties of wheat straw.

    It was suggested that fuel analyses should be presented using molar concentration (mole/kg) in diagrams based on ash transformation reactions and elements forming Lewis acids or bases. This may facilitate the assessment of the combustion behaviour of a fuel. Some comments were made on fuel design and additives, specifically pointing out that phosphorus content should always be carefully considered in relation to alkali and alkaline earth metals in fuels and fuel blends.

  • 266.
    Skoglund, Nils
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Brännvall, Evelina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Waste Science & Technology.
    Grimm, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Kumpiene, Jurate
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Waste Science & Technology.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion of Biosolids in a Bubbling Fluidized Bed Part 2: Environmental Aspects of Ash from Combustion of Biosolids for Application as FertilizerManuscript (preprint) (Other academic)
  • 267.
    Skoglund, Nils
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Energy Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology.
    Bäfver, Linda
    Fahlström, Johan
    Holmén, Erik
    Renström, Caroline
    Fuel design in co-combustion of demolition wood chips and municipal sewage sludge2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 141, no 2, p. 196-201Article in journal (Refereed)
    Abstract [en]

    Municipal sewage sludge (MSS) is a waste stream resource which contains both energy and elements such as phosphorus which could be recycled. If these two aspects of this waste stream resource are to be used to their full potential the sludge should not be used in landfills or road construction. There is some use of sludge in agriculture today but not all MSS produced is suitable for direct use on arable land due to its content of potentially harmful elements, pathogens or anthropogenic chemicals. By combusting sludge that is not used directly in agriculture the problematic organic content could be destroyed. The combustion process also produces an ash that possibly could be used either directly in agriculture or as a raw material for recovering phosphorus and energy could be recovered. Building mono-combustion plants for sewage sludge is not economically feasible in all parts of the world so it is of interest to investigate how MSS can be introduced together with other fuels in existing infrastructure which already have extensive cleaning systems for potentially harmful elements. To investigate this possible path, demolition wood chips (DWC) were co-combusted with municipal sewage sludge (MSS) in a grate-fired combined heat and power plant running at 50% capacity producing 25 MWth and 9 MWel. The amount of MSS that was suitable to introduce in blends was determined using a "fuel fingerprint" based on the composition of the raw materials. Thermodynamic equilibrium calculations were made to evaluate potential problems with slagging based on the ash content prior to the combustion experiments. The fuels were introduced as a reference case with only demolition wood and pre-blended fuel mixtures in two ratios; 65 w/w-% DWC/35 w/w-% MSS and 55 w/w-% DWC/45 w/w-% MSS and were fired for 12 h. The high water content of the MSS affected how much MSS that could be introduced without compromising the heat and power production. The fuel blends worked nicely for 12 h of continuous combustion with small adjustments where the primarily the air inlet configuration was changed. The main problems encountered related to cleaning of the flue gases and to some extent ash removal. The bed ash and fly ash produced was analysed both using ICP-AES (elemental) and XRD (speciation) and the bottom ash was subjected to ash melting tests. The major nutrient phosphorus was mainly found in bottom ash (80 w/w-%) as whitlockites with some hydroxyapatite whereas fly ash (20 w/w-%) contained larger amounts of hydroxyapatite, especially for the reference fuel. The amount of alkali chloride in the fly ash was reduced in favour of alkali sulphate formation.

  • 268.
    Skoglund, Nils
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bäfver, Linda
    Fahlström, Johan
    Holmén, Erik
    Renström, Caroline
    Full-scale Co-combustion of Municipal Sewage Sludge and Demolition Wood Chips in a Combined Heat and Power Plant2014In: Impacts of Fuel Quality on Power Production October 26 –31, 2014, Snowbird, Utah, USA, 2014, 2014Conference paper (Other academic)
  • 269.
    Skoglund, Nils
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kuba, Matthias
    BioEnergy2020+.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Effects of Bed Material Type and Fuel Ash Composition on Layer Formation and Bed Agglomeration in Thermo-chemical Conversion of Biomass and Waste Streams in Fluidized Beds2018In: 23rd International Conference on Fluidized Bed Conversion, 13-17 May 2018, Seoul, Korea, 2018Conference paper (Refereed)
    Abstract [en]

    The role of fluidized beds is increasingly important for challenging and ash-rich fuels, such as fast-growing biomass and waste streams. From a biomass perspective, the relatively homogeneous woody-type fuels are most commonly used in fluidized beds today whereas the fuel feedstock for waste streams is more heterogeneous. A key issue in enabling a broader fuel feedstock for existing and planned fluidized beds is how the fuel ash interacts with bed materials of different types during combustion or gasification. The resulting bed particle coating, layers, and cracks formed in bed grains are responsible for bed agglomeration and bed material deposition mechanisms, but studies have suggested that there is a possibility to affect melting temperatures of bed ash and reduce interaction between fuel ash and bed material through additives or by fuel blend design. Furthermore, it is of interest to extend the life-time of bed materials in the reactor to reduce the amount of material that is generated as waste streams, as well as increase the timespan between bed replacements.The aim of this review is therefore to summarize some of our previous research in this topic, to discuss current knowledge concerning layer formation and bed agglomeration mechanisms, address the benefit for different bed materials, and discuss how fuel ash composition can be used to reduce bed agglomeration issues. This is achieved by comparing studies from different combustion and gasification facilities using different biomasses as well as agricultural residues and waste streams. In particular, the possibility of using fuel blend design to reduce interaction of fuel ash with bed material will be highlighted. Using such approaches, coupled with a fundamental understanding of how differences between bed materials affect layer formation mechanisms, has the potential to reduce operational issues caused by interactions between fuel ash and bed materials as well as increase the potential fuel feedstock.

  • 270.
    Skoglund, Nils
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Strandberg, Anna
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Elemental approaches to additives: mechanisms and dosage2019Conference paper (Other academic)
  • 271.
    Skoglund, Nils
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Energy Engineering, Department of Engineering Sciences & Mathematics, Luleå University of Technology, Luleå, Sweden.
    Werner, Kajsa
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nylund, Göran M.
    University of Gothenburg, Department of Marine Sciences - Tjärnö.
    Pavia, Henrik
    University of Gothenburg, Department of Marine Sciences - Tjärnö.
    Albers, Eva
    Chalmers University of Technology, Department of Biology and Biological Engineering, Division Industrial Biotechnology.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion of seaweed: a fuel design strategy2017In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 165, p. 155-161Article in journal (Refereed)
    Abstract [en]

    The high ash content and varying ash composition in algal biomass is often mentioned as problematic if to beused for thermal energy conversion. This paper suggests an approach where detailed information on ash compositionand predicted ash formation reactions are basis for successful remedies enabling the use of fuels consideredto be difficult. The procedure is demonstrated on seaweed (Saccharina latissima) cultivated for biorefinery purposes. The ash composition of the seaweed was found suitable for co-combustion with Miscanthus x giganteus, an energy crop high in alkali and silicon. Fuel mixtures were combusted in a bubbling fluidized bed reactorand ash samples were analyzed by SEM-EDS and XRD. The results showed that Ca from the seaweed was veryreactive and thus efficient in solving the silicatemelting problems. The fuel design approach was proven successfuland the potential for using otherwise difficult seaweed fuels in synergetic co-combustion was demonstrated.

  • 272.
    Skoglund, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Grid connected large-scale energy storage: Literature review regarding present technology and application, with a complementary case study that investigates the profitability of storage within a wind farm2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the transition from traditional power plants to more environmentally friendly alternatives will generate a need for more flexibility in production, transmission and consumption. Energy storage can be provide the flexibility that are required to continue to have a robust and stable electrical system. The purpose of this report is to give an overview of the electrical energy storage technologies. The classification of energy storage technologies used in this report is mechanical, chemical and electrical. In these three categories were ten different technologies presented with function, advantages, disadvantages, degree of maturity and research area for each technology. The distribution between the globally operational energy storage technologies were presented. Also the framework and regulations for actors to own and operate an energy storage in Sweden. This review was complemented with a case study about connecting a lithium ion battery system to a wind farm. The case investigated the profitability for 20 MW wind farm with a 12 MW and 18 MWh energy storage system for a five and ten-year period. The utilization of the storage was optimized with \textit{What's best} for three different investment cost. The review were done in order to answer: what is the futures energy storage technology?, what applications can be replaced by energy storage for an electricity producer? and what will the effects be of the new actor Aggregator?

    The result from comparing three different prices for lithium ion batteries resulted in a non-profit scenario for all the cases in a five-year period. There were a maximum, minimum and predicted futuristic price, which generated a loss of 731, 220 and 76.6 MSEK for respective case. Only the futuristic price for a ten-year period indicated an profit. The conclusion that can be drawn from this case study is that energy storage is too expensive and the extra income from utilization of the energy storage is not enough to motivate an energy storage investment.

    There are not a single technology that possesses all of the required properties for the applications. In the future there will be a combination of technologies to cover all the applications. For the seasonal storage pumped hydro and compressed air are most promising technologies. The flywheels and supercapacitors can contribute with short powerful burst of energy that are needed for power quality and operating reserves. For the more wide range application such as power fleet optimization and integrate the renewable energy production, batteries in form of lithium ion battery and sodium-sulfur battery will most probably be used.

    For electricity producers energy storage can replace existing solutions. Instead of using diesel generators for black start services, an battery can be used. Also the power quality could be enhanced with batteries acting as filters. The process can be more utilized in a more efficient way with an energy storage.

    The aggregator actor gathers small variable load from e.g several houses and participate on the electricity market. This actor will level out the differences in power demand during the day. It will reduce the losses and reduce the need for grid investments in both the transmission and distribution networks. It would also generate more available frequency reserves and probably change how the market is paying for the generated benefits.

  • 273.
    Smed, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lokal effekttoppsreduktion med elbilar - En del av framtidens smarta elnät?2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to climate targets setup by Sweden to address climate change, the share of intermittent electricity generation is expected to increase, especially solar and wind power. In order to avoid expensive investments and capacity enhancement, due to uneven electricity production, it is important that the already existing power grid is efficient and utilized in a smart way. A larger proportion of renewable electricity generation is not the only change that affects the Swedish electricity system. The number of battery electric vehicles (BEV) in the Swedish car fleet is constantly increasing and as an important part of achieving national targets it is both likely and desirable that it continues. BEVs also carry other potential uses than transport. Due to the battery’s storage capacity, electricity can be stored during charging but also returned later to the grid using Vehicle-to-Grid technology. This means that the BEV can have secondary applications, which can contribute to and be part of, the future power grid.

    The purpose of this study has been to study local power reduction with help of battery electric vehicles ability to recharge electricity to the property when power need is high. The work will furthermore answer the financial incentives that may arise at a local level and how the potential is for BEVs to be an active part of a smart grid.

    To investigate the potential of the BEVs power reduction, the power need for the 755 apartments in the area of Lilljansberget in Umeå for 2016 has been used. A model was then developed in Excel software, the purpose of which was to simulate how the discharges from BEVs, after last arrival time of the day, over a year’s time, affect the new power usage for the area. Since the model in Excel is intended to correspond to actual conditions, parameters related to electric cars, charging and discharging have been determined and applied. The reduction was then optimized with the plug-in program What’s Best! whereby a new maximum usage for the area could be determined. The optimization has been done on a monthly and annual basis and with 3.6 and 6.6 kW discharge effects. Furthermore, scenarios have been investigated claiming that the proportion of BEVs corresponds to 10, 20 and 30% of the area’s car fleet.

    The work shows that driving pattern for cars correlates well with high power peaks, which is reinforced by the results that show that a reduction is possible for most scenarios around 100 kW, corresponding to approximately 25% of the area’s previous maximum power need. The reduction further indicates potential for profitability, as revenue, based on power tariffs, exceeds the degeneration costs of batteries regardless of the scenario and time span for optimization. The most profitable power reduction occurs on an annual basis with 20% BEVs, with an annual revenue of approximately 37,000 SEK, including degeneration costs of the battery. Revenue distributed on participating BEVs is between 700 - 1400 SEK per year. In order to reflect the results of the work in reality, a locally installed battery should also be in place to better guarantee reduction as temporary changes to available BEVs or power usage arise.

    A major reduction in power has proven to be both possible but also directly profitable. On the other hand, revenues, based on costs for power tariffs, are considered to be too low in relation to expenses and remuneration, which makes such an investment difficult to motivate. Continued work on further valuation of power reduction is needed to provide answers to financial compensation that may be applicable. The local power reduction studied in this work greatly changes the power demand for the area but the impact on the grid remains largely small. Therefore, it is concluded that local power reduction with battery electric vehicles is not a solution to the future electrical system, but can at local level, contribute to a smart grid.

  • 274.
    Smedberg, Simon
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energikalkyl med besparingsåtgärden: Ett examensarbete hos Varberg kommun2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Varbergs kommun har som mål att minska energibehovet i deras byggnader med 20% fram till 2020, kommunens resultat kommer jämföras mot referensåret 2009.

    Syftet med denna rapport är att beskriva genomförandet och resultatet av en energikalkyl som levererats till Varbergs kommun. Projektet genomfördes på en förskola som ägs av Varbergs kommun. Förskolan är en större enplansvilla med kallvind, byggåret var 1991.

    Energikalkylen som levererats följer energimyndigheternas mall på energikartläggning [1] och innehåller en utredning av hur energin i byggnaden är fördelad samt energibesparingsåtgärder.

    Energibesparingsåtgärderna som visat goda resultat i energikalkylen har sedan fördelats i två budgetar, en låg budget som har en grundinvestering under 100 000 SEK och en med hög budget som har en grundinvestering under 1 000 000 SEK

     

    Åtgärderna som innefattas i den låga budgeten kommer ge en möjlig energibesparing på totalt 11,5% årligen och en återbetalningstid på sex år. Energibehovet blir då 208 KWh/m2, år.  

     

    Åtgärderna som innefattas i den höga budgeten kommer ge en möjlig energibesparing på totalt 43,6% årligen och en återbetalningstid på ungefär 21 år. Energibehovet blir då 133 KWh/m2, år.

     

    Energibesparingsåtgärder som inte gett något positivt resultat kommer också att beskrivas i denna rapport.

  • 275.
    Soleimani-Mohseni, Mohsen
    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.
    Hasselrot, Rasmus
    Energy simulation for a high-rise building using IDA ICE: investigations in different climates2016In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 9, no 6, p. 629-640Article in journal (Refereed)
    Abstract [en]

    In this paper a model of a high-rise building is constructed in the simulation program IDA ICE. The model is based on an IFC-model of a demonstration building constructed in Ljubljana, Slovenia, as part of an EU-project, EE-high-rise. The model's energy performance was simulated for four cities: Umeå (Scandinavia), Ljubljana (Central Europe), Sibenik (Mediterranean) and Dubai (The Persian Gulf). Furthermore, the climate envelope of the building was modified with the aim to improve the model's energy performance in each of the regions. The results were evaluated according to the energy requirements of passive house standard by the German Passive House Institute. The analysis suggests that the reference building model, which itself incorporates several energy efficient components, was unable to meet the German passive house standard in none of the four cities (Umeå, Ljubljana, Sibenik and Dubai) studied. By providing a combination of energy saving measures, such as modifications of thermal resistance of building envelope, the building may be able to meet the passive house standard in Ljubljana. The analysis concludes that the reduction in window area results in reduction of both heating and cooling demand. Increase in the thickness of the insulation and the thermal resistance of windows reduces the space heating demand for Umeå, Ljubljana and Sibenik (not applied for Dubai) while increasing the cooling demand for these cities. Increased airtightness has marginal effect on heating and cooling demand for all investigated cities. Reduced thermal resistance of windows will decrease cooling demand for Ljubljana, Sibenik and Dubai (not applied for Umeå). Reduced insulation thickness (not applied for Umeå) will decrease cooling demand for Ljubljana and Sibenik but not for Dubai. Reducing the insulation thickness may often result in reduced cooling demand for moderately warm countries since the average outdoor temperature could be lower than the indoor temperature during part of the cooling season. In those situations a reduced insulation thickness can cause heat flow from the relatively hot inside to the colder outside. However, for hot climates like in Dubai where outdoor temperature is higher than the indoor temperature for most of the year, reducing the insulation thickness will increase the cooling demand. This result suggests that the insulation thickness must be chosen and optimized based on heating and cooling demand, internal heat gain, and outdoor climate

  • 276.
    Stoehr, Angelica
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energikartläggning av industriella tork - och härdugnar2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Industriella ugnar har en signifikant påverkan på produktkvalitén och kräver stora mängder energi. I denna rapport har identifiering och kartläggning av energikrävande processer och källor för Ålö AB’s tork - och härdugnar utförts med betoning på aktuella värmeförluster, förbättring av teknologins prestanda samt återvinningspotential. Industriella processer bidrar till stora mängder energianvändning, 38 % av Sveriges totala energianvändning, vilket i vissa fall resulterar i stora mängder överskottsvärme. Förbättring och effektivisering av industriella processer bör ligga i tillverkarens intresse för en mer hållbar och effektiv produktion, ur kvalité -, ekonomi - och miljösynpunkt.

    Processerna torkning och härdning är två viktiga steg inom verkstadsindustrin där torkugnen hettar upp komponenter för avlägsning av fukt och härdugnen hettar upp komponenter för härdning av ytornas färg. Vardera ugn är konstruerad med en separat kylzon där överskottsvärme efter upphettning avlägsnas och släpps ut i form av spillvärme till atmosfären. Tillvägagångssättet för identifiering av värmeflödets storlek utfördes med ett programmerbart styrsystem (PLC-system) för loggning av temperaturoch hastighet. Transmissionsförluster genom ugnarnas klimatskal och el-användning för ugnarna i drift togs fram med hjälp av en IR-termometer och loggning av effekt.

    Spillvärmen för tork - respektive härdugnens kylzon beräknades till 532 000 kWh/år och 699 000 kWh/år och transmissionsförlusterna resulterade i 13 000 kWh/år och 60 000 kWh/år beräknat på 53 % och 78 % av arean på ugnstaken. Ett förslag om tilläggsisolering av 20 cm glasull skulle ge en besparing av transmissionsförlusterna på 48.5 % och 50.7 % per år för tork - respektive härdugnen. Installation av ytterligare fläktar i ugnarnas kylzoner samt ett ökat luftflöde på fläktarna skulle resultera i en snabbare ned-kylningsprocess på grund av ett större och kraftigare luftflöde. Schemaläggning av produktflödet skulle resultera i energibesparingar vid möjlighet för tidigare avstängning av ugnarna.

  • 277.
    Storgärd, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Reaktiv effektkompensering: Kartläggning och utvärdering av olika lösningar för att kompensera reaktivt effekt i vindkraftparker2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As we in Sweden expends our use of wind power and the wind farms grows bigger, the risk of reduced power quality on the electric grid is bigger now than ever. Wind turbines produce a variety of distortions on to the electric grid that threatens to reduce the power quality of the Swedish power grid. One of these distortions is so-called reactive power, reactive power can be described as the foam in a beer glass, the foam is also beer but occupies unnecessary space that could be just for beer. The beer in this case is the active effect and the foam is the unnecessary reactive effect which lowers utilization rate. This is an issue to taken into account in the development of Swedish wind power projects.

     

    In this work, the concept of reactive power as well as its emergence and impact on the network will be treated. Furthermore, methods for reactive power compensation investigated and used to develop models for reactive power compensation of wind farms. The aim of the project was to evaluate different methods for reactive power compensation , as well as explore how these are affected by the wind farms size, topography and location of the regional network . This together with An investigation of the solutions currently available on the market has been the basis for developing a strategy for the compensation of the reactive power in the OX2 's wind farms.

     

    The results show that one can compensate for the produced reactive effect in a number of ways, some better than others. The choice of the compensation method depends primarily on the grid codes in the region. In the wind power context, the compensation to be able to compensate for voltage drops that occur in fast wind changes. The quickest method is ABB's SVC Light® capable control in under 5 ms , but means a greater investment cost 20 million sek. Can we settle the FACTS solution of type SVC , the cost is halved to about 10 million sek.

     

    For parks in size with Maevaara II, the Siemens solution with direct drive turbines or ABB's SVC solution the most suitable in terms of investment costs and park size. Both ABB and Siemens recommend that further investigation is to be done to optimize a solution to the specific case. The investment cost presented in this report is a rough estimation, the different alternatives lies between 10-20 million sek. This is to be used as a guide value to evaluate the different methods. 

  • 278.
    Strandberg, Anna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Thyrel, Mikael
    Swedish University of Agricultural Sciences.
    Lestander, Torbjörn A.
    Sveriges Lantbruksuniversitet, Institutionen för skogens biomaterial och teknologi.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Wheat straw pellet combustion – characterization with X-ray micro-tomography and SEM-EDS analysis2019Conference paper (Refereed)
  • 279.
    Strandberg, Anna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Thyrel, Mikael
    Sveriges Lantbruksuniversitet, Institutionen för skogens biomaterial och teknologi.
    Rudolfsson, Magnus
    Sveriges Lantbruksuniversitet, Institutionen för skogens biomaterial och teknologi.
    Lestander, Torbjörn A.
    Sveriges Lantbruksuniversitet, Institutionen för skogens biomaterial och teknologi.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Char conversion characterizedby synchrotron based X-ray micro-tomograhy and SEM-EDS analysis2017In: EUBCE 2017 – 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, 2017Conference paper (Refereed)
    Abstract [en]

    Fuel and ash properties were studied during fuel conversion by careful examination of char samples at different degrees of char oxidation. Two types of lignocellulosic pellets with different compositions of ash forming elements were used: poplar and straw from wheat. The charred pellets were investigated by synchrotron-based X-ray micro-tomography to create 3D images of the development of cracks, internal cavities, and ash layers during conversion.  Furthermore, SEM-EDS was used to for detailed chemical and morphological information of the ash layers formed. The pore development during pellet conversion was found to deviate from what has previously been described for the structure of solid wood particles. Large cracks and internal cavities were formed extensively already during devolatilization. For poplar, no mobility of the ash forming elements were observed as the burnout proceeded. Ash layer properties varied between the two fuels: poplar formed a porous, permeable, low density and Ca rich ash, whereas wheat straw ash accumulated on the surface in the form of high density melt that develop into bubbles on the surface. As the conversion proceeded, the ash layer covered more of the active char surface area, but without totally blocking the gas transport.

  • 280.
    Strandman, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektiviserande åtgärderpå Robertsfors VA-nät: En förstudie av vilka energieffektiviserande åtgärdersom kan göras på pumpstationer och reningsverk2014Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
  • 281.
    Ström, Kristina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Livscykelanalysen som metod mot ökad miljöhänsyn och hushållning av energi och material: En fallstudie med utvärdering av verktyg anpassade för LCA på byggnader2014Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    The method of analyzing environmental impacts and resource use from a lifecycle perspective is growing in popularity as a method giving the opportunity to lessen negative impact on the environment and depletion of natural resources through comparative analysis. The report focuses on comparing tools available for lifecycle analysis of buildings and building materials as well as the method of LCA in general. A field study is made through analyzing a building with the aid of LCA and according to ISO 14040, and this brings further clarity as to how the method is used. The results show advantages and disadvantages of current LCA tools for buildings as well as pros and cons of the method of LCA itself. The results of the field study indicate the risk that LCA can be used and interpreted subjectively as well as the risk of setting too low data quality. Results also highlight the absence of some important features linked to environmental concern and sustainable resource management. However, if LCA is used in an objective and scientific manner it might be a key to using proper resource management in terms of lessening negative impacts on the environment and depletion of natural resources and some suggstions are made as to how to change the standards of the method.

  • 282. Subhan, Sidra
    et al.
    Rahman, Ata Ur
    Yaseen, Muhammad
    Rashid, Haroon Ur
    Ishaq, Muhammad
    Sahibzada, Maria
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tong, Zhangfa
    Ultra-fast and highly efficient catalytic oxidative desulfurization of dibenzothiophene at ambient temperature over low Mn loaded Co-Mo/Al2O3 and Ni-Mo/Al2O3 catalysts using NaClO as oxidant2019In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 237, p. 793-805Article in journal (Refereed)
    Abstract [en]

    This study reports the ultra-fast and highly efficient oxidative desulfurization (ODS) of dibenzothiophene (DBT) at room temperature over low Mn (0.5 wt%) incorporated Co-Mo/Al2O3 and Ni-Mo/Al(2)O(3 )catalysts using NaClO as oxidant. The effect of disparate operating parameters i.e. mode of catalyst preparation, DBT initial concentration, reaction time, temperature, catalyst and oxidant dose, oxidant type and reaction pH on oxidation process was investigated. Results revealed that remarkably high and ultra-fast A DBT conversion of 100% was achieved within 5 min utilizing 15 mL sample of 2000 ppm (347 ppm sulfur), 0.1 mL of 0.138 M NaClO (O/S6.6 mol/mol), 0.1 g Mn-Co-Mo/Al2O3 catalyst at pH 12, and 25 degrees C reaction temperature. A reaction mechanism for the highly efficient ODS activity of Mn promoted catalysts accredited to the synergistic effect of Mn active phase and high oxidizing power of NaClO was proposed. An overall ODS catalytic activity order of: Mn-Co-Mo/Al2O3 > Mn-Ni-Mo/Al2O3 > Co-Mo/Al2O3 > Ni-Mo/Al2O3 > Mo/Al2O3 was observed. Discernment of the surface morphology and textural properties of fresh and spent catalysts were characterized using Scanning electron microscopy (SEM), X-ray diffraction (XRD), Energy dispersive X-Ray (EDX), and BET surface area analysis which helped in evaluating the catalytic activity results. Due to ultra-fast and highly efficacious nature, simple and safe mechanization, cost effectiveness, and operation at ambient reaction conditions, this study can be envisaged as an effective approach for the ODS of fuel oils on industrial level.

  • 283.
    Sundberg, Maria
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Kartläggning av värmeförluster vid uppvärmning av utskovslucka2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Vid vattenkraftverkens dammar finns utskovsluckor med syfte att vid behov kunna öppnas för att spilla vatten från dammen under kontrollerade former. Detta är mycket viktigt ur dammsäkerhetssynpunkt och avbördning från dammar måste kunna ske året runt för att säkerställa att vattennivån i dammen inte blir för hög. Under vinterhalvåret finns risk för fastfrysning, deformering från islaster och påfrysning av is mot utskovsluckor. Detta kan hindra manövrering av luckor och därigenom hindra dess funktion. För att säkerställa utskovsluckors funktion även vintertid finns ett antal metoder för att hålla luckorna is- och frysningsfria. Dessa metoder är sällan utvärderade ur ett energitekniskt perspektiv och vid många vattenkraftverk finns en potential att minska energiförbrukningen genom en optimering av uppvärmning och isfrihållning av utskovsluckor.

    Detta arbete har utförts som examensarbete inom civilingenjörsutbildningen i Energiteknik vid Umeå universitet 2013, på uppdrag av Statkraft Sverige AB. Arbetet har omfattat undersökning av energiförluster vid uppvärmning av utskovslucka nr. 2 vid Bjurfors nedre vattenkraftverk i Umeälven. Syftet var att utvärdera rådande värmesystem och värmeförluster samt ta fram åtgärdsförslag för minskad energiförbrukning vid uppvärmning av utskovsluckan.

    Värmeförluster beräknades analytiskt utifrån mätvärden tagna från luckan och dess uppvärmningssystem. Värmeförluster från luckan beräknades i form av strålning, konvektion och ledning. Värmeförlusterna i luckans tröskel- och falsvärmesystem bestämdes utifrån mätning av effektförbrukning för den elpanna som är värmekälla i systemet.

    Resultaten visade att värmeförluster uppströms utskovsluckan var dominerande i förhållande till värmeförluster nedströms. Värmeförluster via konvektion från luckan ökar som förväntat med sjunkande utomhustemperatur och ökad vind- och strömningshastighet mot luckan. Ledningsförlusterna nedströms luckan ökade med sjunkande utomhustemperatur medan ledningsförlusterna uppströms minskade under samma förhållanden. Uppströms beror ledningsförlusternas profil på att temperaturen inuti utskovsluckan stiger med ökad utomhustemperatur och temperaturskillnaden mellan luften inuti och vattnet utanför luckan blir större vilket ökar värmeöverföringen. Strålningsförlusterna från luckan var små i förhållande till lednings- och konvektionsförluster och approximerades därför bort. Tröskel- och falsvärmens effektförbrukning minskar med sjunkande utomhustemperatur vilket tros kunna beror på flödesvariationer i kretsen vilket kan påverkar effektförbrukningen i systemet.

    För att minska energiförbrukningen vid uppvärmning av utskovsluckan föreslås följande åtgärder:

     

    • Sänkt temperatur inuti utskovsluckan
    • Återkoppling av ordinarie luftintag till kompressorn för vakhållning
    • Vidare utredning av tröskel- och falsvärme
  • 284.
    Sundberg, Peter
    et al.
    Research Institutes of Sweden, RISE Bioeconomy/Biorefinery and Energy.
    Fagerström, Jonathan
    Åbo Akademi University, Faculty of Science and Engineering, Energy and Environmental Engineering.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hermansson, Sven
    Research Institutes of Sweden, RISE Bioeconomy/Biorefinery and Energy.
    Tullin, Claes
    Research Institutes of Sweden, RISE Bioeconomy/Biorefinery and Energy.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Biomass and peat co-combustion in full scale grate boilers - a primary measure for reduction of fine particle emissions2017Conference paper (Refereed)
  • 285.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Physics.
    Proceedings of the 11th European Conference on Thermophysical Properties (ECTP-11), Umeå, Sweden, 13-16 June 19881989Conference proceedings (editor) (Other (popular science, discussion, etc.))
  • 286.
    Sundström, Göran
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av reaktiv effektinmatning till överliggande nät samt optimal kondensatordrift2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The background of this project is that Vattenfall Eldistribution AB (hereinafter referred to as Vattenfall) will establish a system of fees for input of reactive power. This will be done due to problems in the grid caused by reactive power. Umeå Energi Elnät AB (hereinafter referred to as Umeå Energi) has historically input reactive power, motivating this work which investigates the reactive power in the grid of Umeå Energi and provides information on two alternative approaches to responding to the fee. Alternative 0 entails no installation of compensation technology, and that a subscription for reactive power input is established instead. Alternative 1 entails that compensation technology is installed. To investigate the reactive power, data on reactive power in the grid of Umeå Energi were obtained and processed. Historical operations of capacitor banks for the year 2016 were obtained from the history of events of the control center at Umeå Energi. The operations of the capacitor banks during 2015 could only be obtained from an earlier work at Umeå Energi since the number of events stored in the history is limited.

    By subtracting the capacitor banks’ production from the reactive power measured by Vattenfall in the connections of Umeå Energi, data more representative of underlying phenomena were obtained. Without capacitor production of reactive power, the input was calculated according to the definition of Vattenfall to about 34 MVAr, by using data from 2015 and 2016. For the years 2018 through 2023, changes in reactive power due to changes in the grid of Umeå Energi were calculated. These calculations did not consider inductances, and thus yielded zero-load scenarios with maximum reactive power production. By the year of 2023, the input was calculated to have increased to 59 MVAr due to changes in the grid of Umeå Energi. Assuming that Umeå Energi will not operate the capacitors so that the input is increased, for alternative 0 subscriptions for input of reactive power were suggested for the years 2018 through 2023 by considering the abovementioned 34 MVAr and the changes in the grid. Subscriptions of 41 MVAr and 59 MVAr were suggested for the years 2019 and 2023 respectively. The costs of these were calculated with the fee specified by Vattenfall to SEK 820,000 and SEK 1,187,000 respectively. Calculations with the applicable fee yielded that the yearly cost of possible over-input could amount to a maximum of SEK 76,000 with a 95 % probability, using the corrected standard deviation of the input without capacitor production of reactive power for the years 2015 and 2016.

    Optimal capacitor bank operations were calculated for the years 2015 and 2016 by adding the production of reactive power from existing capacitor banks which yielded the minimum absolute reactive power. Depending on how often the capacitors were operated different results were obtained. An investigation of power quality disturbances due to capacitor bank operations is recommended to achieve an understanding of the conditions for optimal capacitor bank operations.

    It was not deemed economically justifiable to install more advanced compensation technologies such as static VAr compensators since variable reactors are able to compensate daily and seasonal variations in reactive power. The production of reactive power in cables is the largest on the 145 kV level and will increase in the future on this level. It is therefore likely here compensation technologies such as reactors should be installed first.

    To be able to make as good decisions as possible concerning the reactive power, it is recommended to as soon as possible commence a working method as if the fee system had already come into effect; thus increasing the amount of representative data.

  • 287.
    Sundström, Henrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering panna 8.: Omplacering av rökgasfläkt.2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 288. Svanberg, Martin
    et al.
    Olofsson, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Flodén, Jonas
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analysing biomass torrefaction supply chain costs2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 142, p. 287-296Article in journal (Refereed)
    Abstract [en]

    The objective of the present work was to develop a techno-economic system model to evaluate how logistics and production parameters affect the torrefaction supply chain costs under Swedish conditions. The model consists of four sub-models: (1) supply system, (2) a complete energy and mass balance of drying, torrefaction and densification, (3) investment and operating costs of a green field, stand-alone torrefaction pellet plant, and (4) distribution system to the gate of an end user. The results show that the torrefaction supply chain reaps significant economies of scale up to a plant size of about 150-200 kiloton dry substance per year (kton(DS)/year), for which the total supply chain costs accounts to 31.8 euro per megawatt hour based on lower heating value ((sic)/MWLHV). Important parameters affecting total cost are amount of available biomass, biomass premium, logistics equipment, biomass moisture content, drying technology, torrefaction mass yield and torrefaction plant capital expenditures (CAPEX).

  • 289.
    Svanlund, Nils Viktor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Uppvärmning av Wallmarksgården2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Västerbotten museum houses a number of buildings moved from various parts of Västerbotten to show how life on a farm in the 1800's looked like. Today the houses are cold during the winter when they have no heating system. The museum wishes to install a heating system in one of the houses, Wallmarkgården built in 1736, to enable the use of the building during the winter season. The heating system shall change the buildings appearances both interior and exterior as little as possible.

    Three different heating systems, mobile pellet stove, water fan heater and building fans have been compared for five different operating conditions. The various operating conditions described in the case A-E, three of the cases have a constant indoor temperature and the two have varying temperature with a base temperature of 0 ° C and 10 ° C and heated two days a week to 20 ° C. In order to compare the different heating systems a LCC analysis is made for the different cases.

    The energy calculation of the building shows that the energy demand is 220 kWh / m². An LCC analysis shows that a fan heater which is connected to district heating system is the best system by an economic point of view in four of the five operating cases.

  • 290.
    Svensson, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energibesparingar i tegelbyggnader2018Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    This work is about a residential area consisting of five buildings on Vallhallavägen 38 in Örnsköldsvik, Sweden. The work was done because there was an interest in seeing what types of energy savings you could do on the buildings and how much energy you could save by doing them. The energy savings that where examined where additional insulation on the exterior walls, exchange of current windows to better ones, modification of the ventilation systems, and implementation of solar cells and solar collectors on the buildings. All calculations of the building's energy savings were done by IDA ICE 4.8, a simulation software developed by the Swedish company EQUA Simulation AB for studies of indoor climate and energy use in buildings. After all the calculations of the building's energy use were done, economic calculations were made for each type of energy saving to find out if an investment should be done or not. The results showed that all energy savings would reduce the energy use of the buildings to a certain extent, but that it probably would be wise to not invest in them all, as some of them saved very little energy compared to how comprehensive it would be to install them in the buildings. The biggest saving that resulted in a 34,5% reduction of energy use was gained by replacing the ventilation systems, while the smallest saving that resulted in a 3,6% reduction of energy was gained from additionally isolating certain parts of the building’s exterior walls.

  • 291.
    Svensson, Mattias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av energiförbrukning, Akzo Nobel Functional Chemicals AB2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The main purpose of this project was to make a survey of the steam and electricity consumption at Akzo Nobel Functional Chemistry AB and give suggestions of how to minimize them. These three different areas were focused on. First to make a survey of all the most important consumers, second to find the electricity consumption of the air compressors and the amount of waste heat produced from them. The third area was to calculate a model of how much fresh water that is used during a cooling sequence in the water based heating/cooling system of the reactors and give a suggestion of a suitable reuse for this water.

    The main result is a total survey of the energy consumption in steam and electricity. The survey shows that the second largest group after drying is heating of ventilation which gives big potentials of reducing the total steam consumption if there is a way of being self supporting in ventilation heat. Because of the large amount of waste heat from the process equipment to the surrounding it could be possible to make the ventilation unit self supporting in heat by using an air to air heat exchanger.

    The second area that was decided to focus on was the two air compressors that is consuming a lot of electricity and produce a lot of hot water that could be reused in other applications. The waste heat from the air compressors may be used to preheat the water based heating system of the ventilation units.

    The third area that’s been looked closer into is the inefficient heating/cooling circuit of the reactors that also produces a lot of hot waste water. The simplest solution to this problem is to accumulate the amount water that’s holds a certain minimum temperature and recycle it in the next heating sequence. The calculated model gives the amount produced hot water which depends on the chosen temperature interval.

  • 292.
    Södergren, Nina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energikartläggning Lagret 8 Skellefteå: Energikartläggning och åtgärdsplan på uppdrag av Fastighets AB Polaris i Skellefteå2015Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    This report is the result of three years of studying to get a degree in Bachelor of Science in energy technology and it contains an energy audit of Lagret 8 in Skellefteå owned by Fastighets AB Polaris. The building consists of three connected buildings which are rented by five different companies. There are also vacant parts of the property.

    This energy audit includes the investigation of energy for ventilation, radiators and heat, water, air-conditioning, lighting and electricity consumption and analysis of the building envelope Based on this investigation an action plan have been developed and the changes to be done will hopefully lead to a better environment inside the building and also contribute to lower the energy consumption.

     

    The calculations of energy savings and pay-back time in the action plan are focused on the ones that Polaris can affect and do something about. The ones that can be affected are for example energy for ventilation and air-conditioning. Operational energy is something that is more difficult to influence as it varies with the type of activity that takes place in the facility and to what extent

     

    The action plan to improve the energy performance of Lagret 8 are sorted for every part of the building. They are presented below:

     

    For Fastighets AB Polaris (SSC, Schneider Electrics and Feelgood företagshälsa)

    • Ventilation fan replacement on TA09
    • Additional insulation of roofs on Xzakt building
    • Balancing the temperature of the radiators
    • Winter compensation to TA09

    For Xzakt Kundrelationer AB

    • Ventilation fan replacement on TA01
    • Reduce the operating time of TA01
    • CO2 control with a throttle in the lunchroom 106 Paus
    • Winter compensation of TA01

    For SSC Klingan AB Skelleftea

    • Ventilation fan replacement on TA06Klingan
    • Change to RC doors
    • Presence -controlled ventilation in storage area ( Rooms number: WELDER )
    • Winter compensation of TA02 , TA03 and TA05 .
  • 293.
    Söderlind, Ann
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    En unik energisnål byggnad i Örnsköldsviks kommun: En uppföljning, en bedömning och en jämförelse2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I detta examensarbete har Alne församlingshem i Örnsköldsviks kommun varit den centrala delen. För att företaget Tecnicon, som projekterat byggnaden, ska få ett kvitto på vad som blev bra och vad som blev mindre bra från projektering, så jämförs energiprestandan mellan projekterad och uppföljd. Utöver detta undersöktes det om byggnaden blev ett lågenergihus samt ur en miljömässig, energimässig och ur ett ekonomiskt perspektiv jämfördes Alne församlingshems klimatskal med ett klimatskal som uppfyller energiprestanda kraven som BBR ställer.

    För att genomföra detta gjordes en energideklaration över byggnadens energianvändning och som jämfördes med det projekterade resultatet. Värden för energiberäkningarna har avlästs på el- och vattenmätare, hämtats från elbolaget, i tekniska datablad, schablonvärden samt antagna värden. Som hjälp vid energiberäkningarna användes ett Excel-dokument där energiprestandan beräknades. Byggnaden undersöktes utifrån FEBY-12:s kravspecifikation om den uppfyllde kraven för ett lågenergihus och vilket lågenergihus byggnaden i så fall ska benämnas för. Energiberäkningarna i Excel-dokumentet gjordes för de två klimatskalen, dessutom beräknades en ekonomisk kalkyl för respektive klimatskal.

    Jämförelsen mellan projekterad och uppföljd energiprestanda visade att resultatet vid uppföljningen blev lägre, vilket är önskvärt. Det visade sig även att energianvändningen för fastighetsel var betydligt högre vid uppföljning än vid projektering. Det beror på att en elvärmekabel varit felaktigt injusterad och har uppskattningsvis dragit runt 5500 kWh/år för mycket. Resultatet av de krav som undersöktes för ett lågenergihus visade att byggnaden uppfyllde kraven för ett minienergihus. Koldioxidutsläpp ökar med ett ökat energibehov. Ett sämre klimatskal medför en högre energianvändning på grund av högre förluster, men med en lägre investeringskostnad som ett resultat av mindre isolering.  

    För att vara säker på att byggnaden kan klassas som ett minienergihus bör resterande krav, som denna rapport utelämnar, för ett minienergihus undersökas och uppfyllas. Om de interna elmätarna varit i funktion så skulle energiberäkningarna blivit mer rättvisande. Verksamheten var inte heller i full gång förrän efter några månader.

    För att uppnå EU:s och Sveriges mål inför år 2020 så är lågenergihuset Alne församlingshem ett steg i rätt riktning. Byggnad med låg energianvändning, lägre koldioxidutsläpp än vanliga byggnader samt att de producerar förnybar energi. 

  • 294.
    Tallus, Emma
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Dimensionering av ackumulatortank: Undersökning hur en ackumulatortank kan införas till Övertorneå fjärrvärmenät samt dess ekonomiska innebörd2015Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
  • 295.
    Thomas, Lisa
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Solcellers påverkan på landsbygdsnät2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Elnätets utformning står mitt i en stor förändring i och med decentraliseringen där allt fler upptäcker fördelarna med att producera egen el. Antalet nätanslutna solceller ökar och detta förväntas även gälla fortsättningsvis. Om solcellsanläggningar som nätansluts har hög effekt eller om elnätet är svagt kan förstärkande åtgärder vara nödvändiga. Detta projekt syftade till att utreda vilka problem solceller kan orsaka på svaga delar av nätet samt åtgärder för att minska problematiken. Projektet klargör även vad som bör beaktas vid dimensionering av elnät nät solceller ansluts.

    För att uppnå syftet inleddes projektet med informationsletande och producerande av en litteraturrapport. Därefter dimensionerades en framtida solcellsanläggning och nätet kring en befintlig anläggning utvärderades. Dimensioneringen och utvärderingen utfördes med hjälp av simuleringar i dpPower. Vid utvärderingen av den befintliga anläggningen genomfördes även en analys av elkvalitetsmätningar samt mätning av förimpedans på två olika lågspänningsnät. Den ekonomiska aspekten analyserades också i form av jämförelse av effektförluster i olika kablar.

    Nätet kring den framtida solcellsanläggningen undersöktes med avseende på spänningsändringar vid inkoppling av solcellsanläggningen och långsamma spänningsändringar. Resultatet från simuleringar visar att en anläggning på 21 kW kan anslutas till nätet utan behov av förstärkning. Enligt grovuppskattningskurvor för nödvändig nätstyrka vid anslutning av mikroproduktion som finns tillgängliga i handboken MIKRO blir resultatet 23 kW.

    Utvärderingen av nätet kring den befintliga solcellsanläggningen innefattade undersökning av spänningsvariationer, mätning och beräkning av förimpedans samt analys av elkvalitetsmätningar. Resultatet visar att den omdimensionering som utfördes i samband med att anläggningen nätanslöts var nödvändig och att nätet förmodligen kommer behöva förstärkas ytterligare med en större transformator om fler solcellsanläggningar ansluts i framtiden. Elkvalitetsmätningarna visar på höga flimmernivåer men det kan dock inte fastställas om dessa härrör från solcellsanläggningen.

    Genom mätning och beräkning av förimpedans drogs slutsatsen att mätinstrumentet påverkas vid mätning i närheten av en solcellsanläggning. De uppmätta värdena i närheten av solcellsanläggningen stämmer inte med de simulerade och beräknade värdena. Nyare versioner av mätinstrumentet finns tillgängliga hos leverantören och bör testas på samma nät för att se om mätvärdena stämmer bättre.

    Vid beräkning av effektförluster jämfördes olika kabelalternativ. Resultatet visar att det ofta lönar sig ekonomiskt att välja en grövre kabel med högre inköpspris och lägre förluster per meter kabel än tvärtom. De minskade förlustkostnaderna mellan en grövre och en klenare kabel är alltså större än skillnaden i inköpspris under kablarnas livslängd.

    Förutom de slutsatser för de specifika anläggningarna som projektet utmynnade i drogs även några mer generella. De vanligaste problemen som uppstår vid anslutning av solceller på nätets svaga delar är elkvalitetsproblem, oftast i form av spänningsvariationer. För att minska problematiken kan nätet behöva förstärkas, exempelvis i form av kabeldimensionering. Då bör spänningsändringar vid in- och urkoppling av solcellsanläggningen, långsamma spänningsändringar, effektförluster och möjlig utbyggnation av området beaktas.

  • 296. Trubetskaya, Anna
    Fast pyrolysis of biomass at high temperatures2016Other (Other academic)
  • 297. Trubetskaya, Anna
    et al.
    Beckmann, Gert
    Jensen, Peter Arendt
    Jensen, Anker Degn
    Glarborg, Peter
    A way of a single biomass particle shape characterization in a CFD model2014Other (Other academic)
  • 298.
    Trubetskaya, Anna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Brown, Avery
    Tompsett, Geoffrey A.
    Timko, Michael T.
    Kling, Jens
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsen Andersen, Mogens
    Umeki, Kentaro
    Characterization and reactivity of soot from fast pyrolysis of lignocellulosic compounds and monolignols2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 212, p. 1489-1500Article in journal (Refereed)
    Abstract [en]

    This study presents the effect of lignocellulosic compounds and monolignols on the yield, nanostructure and reactivity of soot generated at 1250 °C in a drop tube furnace. The structure of soot was characterized by electron microscopy techniques, Raman spectroscopy and electron spin resonance spectroscopy. The CO2 reactivity of soot was investigated by thermogravimetric analysis. Soot from cellulose was more reactive than soot produced from extractives, lignin and monolignols. Soot reactivity was correlated with the separation distances between adjacent graphene layers, as measured using transmission electron microscopy. Particle size, free radical concentration, differences in a degree of curvature and multi-core structures influenced the soot reactivity less than the interlayer separation distances. Soot yield was correlated with the lignin content of the feedstock. The selection of the extraction solvent had a strong influence on the soot reactivity. The Soxhlet extraction of softwood and wheat straw lignin soot using methanol decreased the soot reactivity, whereas acetone extraction had only a modest effect.

  • 299. Trubetskaya, Anna
    et al.
    Jensen, Anker Degn
    Experimental investigations and modeling of devolatilization based on superimposed kinetics of biomass2016Other (Other academic)
  • 300. Trubetskaya, Anna
    et al.
    Jensen, Anker Degn
    Andersen, Mogens Larsen
    Talbro Barsberg, Søren
    Characterization of Free Radicals By Electron Spin Resonance Spectroscopy in Biochars from Pyrolysis at High Heating Rates and at High Temperatures2016Other (Other academic)
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