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  • 1.
    Borgström, Fredrik
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Coyet, Jonas
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Waste heat recovery system with new thermoelectric materials2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Increasing fuel prices, higher demands on "greener" transports and tougher international emission regulations puts requirements on companies in the automotive industry in improving their vehicle fuel efficiency. On a typical heavy duty Scania truck around 30% of the total fuel energy is wasted through the exhaust system in terms of heat dissipated to the environment. Hence, several investigations and experiments are conducted trying to find ways to utilize this wasted heat in what is called a waste heat recovery (WHR) system. At Scania several techniques within the field of WHR are explored to find the profits that could be made.

    This report will cover a WHR-system based on thermoelectricity, where several new thermoelectric (TE) materials will be investigated to explore their performance. A reference material which is built into modules will be mounted in the exhaust gas stream on a truck to allow for measurements in a dyno cell. To analyze new materials a Simulink model of the WHR-system is established and validated using the dyno cell measurements. By adjusting the model to other thermoelectric material properties and data, the performance of new TE materials can be investigated and compared with today’s reference material.

    From the results of the simulations it was found that most of the investigated TE materials do not show any increased performance compared to the reference material in operating points of daily truck driving. This is due to dominance of relatively low exhaust gas temperatures in average, while most advantages in new high performing TE-materials are seen in higher temperature regions. Still, there are candidates that will be of high interest in the future if nanotechnology manufacturing process is enhanced. By using nanostructures, a quantum well based BiTe material would be capable of recovering 5-6 times more net heat power compared to the reference BiTe material. Another material group that could be of interest are TAGS which in terms of daily driving will increase the power output with pending values between 40-80 %. It is clear that for a diesel truck application, materials with high ZT-values in the lower temperature region (100-350°C) must be developed, and with focus put on exhibiting low thermal conductivity for a wide temperature span.

  • 2.
    Molin, Johan
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    The Present and Future Role of Energy Recovery in Waste Management - A Case Study of Linköping and Norrköping2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the European Union 500 million tonnes of waste are either incinerated without energy recovery,or deposited in landfills, which could have been recycled instead. The European Union initiated theCircular Economy Package in order to decrease the amount of waste being generated, lost inlandfills, and to increase the recycling and usage of recycled material. However, the CircularEconomy Package did not contain any targets focusing on energy recovery, and only mentionedenergy recovery as having a role in decreasing the amount of waste deposited in landfills. TheCircular Economy Package was in the end of 2014 withdrawn but will come back with moreambitious targets. In Sweden energy recovery is treating more than 50% of the municipal waste andwould then be affected by the targets of the Circular Economy Package when it comes back.This thesis focuses on Linköping and Norrköping to identify the what role energy recovery have inthese municipalities, both present and future, as well as asking the questions of how waste is valuedas a resource.The results were that both municipalities thought that it was important to have separate sorting ofmunicipal waste, to separate organic waste from the rest, in order to use it in material recycling andthe rest in energy recovery. In both municipalities the energy recovery had the role of treating themunicipal waste which was found to be not recyclable, as well as to deliver heat and electricity. Allof the organisations were identified to have a high environmental value on waste, but the economicvalue of waste were low or negative. The municipalities also knew little of the Circular EconomyPackage, but were aware of it, while the energy companies knew a little more of it, but still littlecompared to their national interest organisations Avfall Sverige and Svensk Fjärrvärme. All of theorganisations had identified similar challenges such as increased focus on recycling, minimisationof waste, but also a focus on decreasing amount of hazardous substances in products in order todecrease the amount of waste which needed to be deposited in landfills.

  • 3.
    Randell, Per
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Numerical Simulation of Temperature and Velocity Profiles in a Horizontal CVD-reactor2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Silicon Carbide (SiC) has the potential to significantly improve electronics. As a material, it can conduct heat better, carry larger currents and can give faster responses compared to today’s technologies. One way to produce SiC for use in electronics is by growing a thin layer in a CVD-reactor (chemical vapour deposition). A CVD-reactor leads a carrier gas with small parts of active gas into a heated chamber (susceptor). The gas is then rapidly heated to high temperatures and chemical reactions occur. These new chemical substances can then deposit on the substrate surface and grow a SiC layer. This thesis investigates the effect of different opening angles on a susceptor inlet in a SiC horizontal hot-walled CVD-reactor at Linköping University. The susceptor inlet affects both the flow and heat transfer and therefore has an impact on the conditions over the substrate. A fast temperature rise in the gas as close to the substrate as possible is desired. Even temperaturegradients vertically over the substrate and laminar flow is desired. The CVD-reactor is modeled with conjugate heat transfer using CFD simulations for three different angles of the inlet. The results show that the opening angle mainly affects the temperature gradient over the substrate and that a wider opening angle will cause a greater gradient. The opening angle will have little effect on the temperature of the satellite and substrate.

  • 4.
    Avdic, Kenan
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    On-chip Pipelined Parallel Mergesort on the Intel Single-Chip Cloud Computer2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the advent of mass-market consumer multicore processors, the growing trend in the consumer off-the-shelf general purpose processor industry has moved away from increasing clock frequency as the classical approach for achieving higher performance. This is commonly attributed to the well-known problems of power consumption and heat dissipation with high frequencies and voltage.

    This paradigm shift has prompted research into a relatively new field of "many-core" processors, such as the Intel Single-chip Cloud Computer. The SCC is a concept vehicle, an experimental homogenous architecture employing 48 IA32 cores interconnected by a high-speed communication network.

    As similar multiprocessor systems, such as the Cell Broadband Engine, demonstrate a significantly higher aggregate bandwidth in the interconnect network than in memory, we examine the viability of a pipelined approach to sorting on the Intel SCC. By tailoring an algorithm to the architecture, we investigate whether this is also the case with the SCC and whether employing a pipelining technique alleviates the classical memory bottleneck problem or provides any performance benefits.

    For this purpose, we employ and combine different classic algorithms, most significantly, parallel mergesort and samplesort.

  • 5.
    Sundin, Fia
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Occurrence of insects in relation to short term forest fire history2014Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Several boreal insect species are pyrophilic and are more or less dependent on recently burned forest. Many pyrophilic species are attracted to potential substratum-rich recently burned forest by smoke and heat. Modern forestry has dramatically reduced the amount and size of forest fires in northern Europe during the last century and as a result several of the pyrophilic species are now threatened. The aim of this study was to analyse how the occurrence of insects such as Diptera of the pyrophilic genus Microsania, pyrophilic Coleoptera, obligate saproxylic Coleoptera and Coleoptera with unknown fire-dependency were affected by the forest fire history during the last 14 years. The aim was also to analyse what effect the spatial and temporal scales of the forest fire history has on the occurrence of these insects. This was done using smoke attraction traps, a unique method for catching pyrophilic insects without an actual forest fire, and analysing the results with a unique regional short term forest fire history dataset, containing all fires between the years of 1998-2011 in Östergötland county in Sweden. The forest fires were clustered and more abundant in the eastern parts of the county. Seven out of eleven pyrophilic beetles were positively correlated with recent forest fires, mostly for the smaller spatial scales, 100 m – 5000 m. The abundance of many beetles with unknown fire-dependency were associated with recent forest fires. The general ecology for many of these species is not well known but some of these beetles might be favoured by different substrates that are created by fires. Strategically placed conservation burns can help to increase the spatial and temporal connectivity of forest fires to conserve both fire dependent and generally associated insects in the future.

  • 6.
    Sjöström, Dick
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Proteomic study of microbiopsies from women with trapezius muscle pain and from healthy women2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Trapezius myalgia is a pain condition that usually develops in people with repetitive and stressful work tasks, which can lead to chronic widespread pain (CWP). This work compares protein expression levels in healthy women with those in women who have chronic widespread pain, including pain in the trapezius muscle, by using a proteomic approach.  Twodimensional gel electrophoresis and silver staining with a subsequent digital quantification of protein spots was used to detect spots which had significantly higher protein levels in either group. Preparative gels were made and stained with SYPRO Ruby, the protein spots that were significantly different between the groups were picked from the SYPRO Ruby gels and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF.

    The optical density of seven protein spots were significantly decreased in the trapezius muscle of the CWP subjects; however the standard deviations were notably high. Five of the seven proteins could be identified as desmin, creatine kinase B-type, serum albumin, heat shock protein beta-1 and slow skeletal muscle troponin T. Apart from serum albumin, all these proteins can possibly be responsible for pain in the trapezius muscle in CWP.

    In conclusion, this study demonstrates that two-dimensional gel electrophoresis in combination with mass spectrometry is a powerful tool to identify potential biomarkers of musculoskeletal pain in subjects with CWP. The results may provide new insights into the mechanisms and patho-physiology of trapezius myalgia.

  • 7.
    Karczmarz, Veronika
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Thermal comfort in young broiler chickens (Gallus gallus domesticus) inferred from metabolic expenses.2014Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    The thermoneutral zone (TNZ) curve lies between the ambient temperatures (Ta) where an endothermic animal uses the least amount of energy to maintain a balance between the heat production from the animal’s own metabolism and the heat lost to the environment. If the animal is exposed to Ta’s over the upper critical temperature (UCT), which is the highest temperature that is still in the TNZ, the animals have to use energy to cool down. If they are exposed to temperatures lower than the lower critical temperature (LCT), which is the lowest temperature that is still in the TNZ, the animal have to use energy to warm up. In the present study oxygen consumption was measured at different Ta’s to determine the TNZ in two and three week old broiler chickens (Gallus gallus domesticus). Two different protocols were used and compared, a pseudorandom protocol in which chickens were exposed to seven temperatures in two hour periods for each run and a more typical progressive protocol in which Ta decreased gradually, one or two degrees per hour. The TNZ in two weeks old chickens was between 30.7 ˚C- 36.4 ˚C and between 28.8 ˚C- 32.7 ˚C in the three weeks old chickens. In chickens the TNZ shifts remarkably during the first few weeks of life towards lower temperatures as the animals acquire thermoregulatory competence. The method with a pseudorandom protocol takes more factors, like activity, into consideration than a typical progressive protocol.

  • 8.
    Lin, Keng-Yu
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Thin films for thermoeletric applications2014Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Global warming and developments of alternative energy technologies have become important issues nowadays. Subsequently, the concept of energy harvesting is rising because of its ability of transferring waste energy into usable energy. Thermoelectric devices play a role in this field since there is tremendous waste heat existing in our lives, such as heat from engines, generators, stoves, computers, etc. Thermoelectric devices can extract the waste heat and turn them into electricity. Moreover, the reverse thermoelectric phenomenon has the function of cooling which can be applied to refrigerator or heat dissipation for electronic devices. However, the energy conversion efficiency is still low comparing to other energy technologies. The efficiency is judged by thermoelectric figure of merit (ZT), defined by Seebeck coefficient, electrical conductivity and thermal conductivity. In order to improve ZT, thin film materials are good candidates because of their structural effects on altering ZT. 

     

    Ca3Co4O9 thin films grown by reactive radio frequency magnetron sputtering followed by post-annealing process is studied in this thesis. Structural properties of the films with the evolution of elemental ratio (Ca/Co) of calcium and cobalt have been investigated. For the investigations, three samples having elemental ratio 0.82, 0.72, and 0.66 for sample CCO1, CCO2 and COO3, respectively, have been prepared. Structural properties of the films have been investigated by X-ray diffraction (XRD) θ-2θ and pole figure analyses. Surface morphology of the films has been investigated by scanning electron microscopic (SEM) analyses. The highly oriented and phase pure epitaxial Ca3Co4O9 thin films were obtained in the end.

     

    Mixing of ScN and CrN to obtain ScxCr1-xN solid solution thin films by DC magnetron sputtering is the other task in this thesis. Growth of ScN and CrN thin films were studied first in order to get the best mixed growth conditions. The phase shifts between ScN (111) and CrN (111) peaks were observed in mixed growth films by XRD θ-2θ measurements, indicating the formation of ScxCr1-xN. Surface morphology of the films were investigated by SEM. The (111)-oriented ScxCr1-xN thin films with decent surface smoothness grown by DC magnetron sputtering at 600 °C in pure nitrogen with bias were developed. 

  • 9.
    Gustafsson, Fredrik
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, The Institute of Technology.
    Stabila approximationer av ett illaställt Cauchy-problem för värmeledningsekvationen i flera lager2014Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    I den här kandidatuppsatsen betraktar vi ett illa ställt Cauhy-problem för värmeekvationen i tunna väggar. Problemet kan matematiskt formuleras som: givet brusiga mätningar u x(L, t) och u(L, t) av ux(L, t) och u(L, t) längs linjen x = L bestäm lösningen för u(x, t) för 0 ≤ x, där u uppfyller värmeledningsekvationen ut = ((x)ux)x. Problemet dyker upp i många tillämpningar när man vill uppskatta en temperatur men att en direkt mätning inte låter sig göras. Man mäter en temperatur på ett annat ställe och beräknar temperaturen i den punkt man är intresserad av. Tyngdpunkten i uppsatsen ligger i att undersöka det inversa värmeproblemet i en vägg med flera lager. Det modelleras med att (x) antas vara styckvis konstant.    Problemet undersöks med Fourieranalys. Analysen visar att problemet är extremt illaställt och att det beror på förstärkning av höga frekvenser från mätbruset. Vi presenterar numeriska metoder för att regularisera och lösa problmet. Numersiska exempel som illustrar illaställdheten och regulariserade lösningar ges.

  • 10.
    Chen, Huijuan
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems.
    Janbakhsh, Setareh
    Linköping University, Department of Management and Engineering, Energy Systems.
    Larsson, Ulf
    university of Gavle.
    Moshfegh, Bahram
    Linköping University, Department of Management and Engineering, Energy Systems.
    Comparisons of ventilation performance of different air supply devicesin in an office environmentManuscript (preprint) (Other academic)
    Abstract [en]

    The aim of this study was to compare ventilation performance of four different air supply devices in an office environment with respect to thermal comfort, ventilation efficiency and energy-saving potential, by performing numerical simulations. The devices have the acronyms: Mixing supply device (MSD), Wall confluent jets supply device (WCJSD), Impinging jet supply device (IJSD) and Displacement supply device (DSD). Comparisons were made under identical set-up conditions, as well as at the same occupied zone temperature of about 24.2°C achieved by adding different heat loads and using different air-flow rates. Energy-saving potential was addressed based on the air-flow rate and the related fan power required for obtaining a similar occupied zone temperature for each device.

     

    Results showed that the IJSD could provide an acceptable thermal environment while removing excess heat more efficiently than the MSD, as it combined the positive effects of both mixing and stratification principles. This benefit also meant that this device required less fan power than the MSD for obtaining equivalent occupant zone temperature. The WCJSD studied in this paper behaved somewhat like the MSD, but caused higher draught discomfort at ankle level because of very high supply velocities, which was might due to small nozzle diameter of the supply device. Further studies are required for the WCJSD to make these conclusions applicable for general conditions. The DSD showed a superior performance on heat removal, air exchange efficiency and energy saving to all other devices, but it had difficulties in providing acceptable vertical temperature gradient between the ankle and head levels for a standing person.

  • 11.
    Sabigoro, Rocky A.
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, The Institute of Technology.
    Design and Manufacturing of Pneumatic Test Stand for Rod-less Cylinder vertical application2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Within LiU Fluid laboratory there had been a number of hydraulic and pneumatic test stands for research projects and teaching. The effort was needed to do more extension within the field of pneumatics. This thesis was about designing, manufacturing, building and testing the Test Stand for vertical application of pneumatic rodless cylinder. It consisted of three main parts; mechanical structure, pneumatic system and electrical and electronics. The design part focused more on the mechanical structure and pneumatic system. Electrical and electronics had to be installed to facilitate actuation and control of the system after mechanical and pneumatic components were assembled together. The mechanical structure consisted of three main parts; cabinet, carriage and ball balancer. For each part three concepts were generated, evaluated and selected to obtain the most promising concept for further development. The design values were given such that the mechanical structure should have total weight not exceeding 500 kg. The pneumatic system would supply maximum pressure of 8 bar. Upstream pressure was considered to be 6 bar after 25% pressure drop assumed to occur in the system. The mass to be lifted was typically 26 kg moving at a maximum speed of 2 m/s. The whole design process was carried out with safety and design for assembly in mind. The methodologies applied in the design included; identification of need, concept generation, concept selection, CAD modeling and simulation and FE Analysis. Development of concepts involved CAD drawings (3D and 2D) in CATIA V5, calculations and selection of appropriate materials for each component. The pneumatic cylinder applied in this design was a rod-less cylinder (Bosch Rexroth; RTC-DA, MNR: R480628571) with a Piston diameter of 50 mm, stroke of 1.2 m and cushioning stroke of 20 mm. More design information on RTC-DA was not available therefore the information in appendix A was based on series RTC-BV which had close similarities with series RTC-DA. The carriage that moves up and down along the cylinder stroke was designed with a mechanism that imparted disturbance to the system. The mechanism could be set to impart either 100.7 N or 151.02 N disturbance. The design was done with the assumptions that:

     Spring force Fs and extension x were constant

     The system had sonic flow characteristics and critical flow appeared in meter out orifice.

     The air was perfect gas which obeyed equation of state

     Specific heat was constant

     Viscosity was constant

     Flow was one dimensional

     System pressure drop was 25% of the maximum supply pressure.

    Dynamics of the system were estimated analytically and by means of simulation. Corresponding parameter values such as pressure, velocity, flow rate, cushioning stiffness, cushioning force and acceleration were obtained and compared. The product in general conformed to the specifications made prior to the design process.

  • 12.
    Wahlström, Krister
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Värmestrålning i ugn för hushållsbruk, modellering – simulering - experiment2005Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In many microwave ovens are grill elements, which give color to the food surface. Some future models of microwave ovens are designed with no turning table and the food will therefore be stationary. The grill elements and their reflectors must therefore be optimized so the heat radiation if possible will be evenly distributed in the oven. The purpose of this work is to examine how the heat radiation in the ovens can be calculated, thus the optimization can be carried out. The heat radiation in an existing microwave oven has been simulated and measured. The simulations and measurements show that the distribution of the heat radiation should be calculated with sufficient accuracy when the quartz glass that surrounds the filament of the grill element is neglected, reflections are assumed to be diffuse and the surfaces are assumed to be mathematically grey. The emissivities of the surfaces

  • 13.
    Bovellan, Johan
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Talani, Elias
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Analysis of electric quality2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In todays society it’s usual with non linear loads in the electric power system. These loads contribute to the problems in the distriubution net.

    This student thesis will describe the different types of problems that can evolve with specific focus on a problem at Billerud AB Skärblacka. The purpose with the work was to see what causes a heat problem in one of their transformers.

    The report begins with a theoretic part that describes diffrent power quality concepts and informations areas necessary for the work.

    After the theoretical part the system is described and also the harmonics- and asymmetry measurments done with purpose to analyze the heat problem.

    The measurments were logged for a couple of days to be able to get information about different loads, to see if that had any effect on the amount of the harmonics.

    There is also a simulation of the system done, which indicates that the problem doesn’t have to depend on the frequency converter in the system.

    The investigation indicates that it can be the transformer that isn’t correctly dimensioned to handle the amount of harmonics from the frequency converter and that’s why it gets overheated.

    The result indicates that the amount of harmonics from the converter is as the supplier issued. A difficultiy during the work was to be able to measure on all connections, since the voltage and current are too high for the measurement equipment and also hard to reach in all areas of the system.

    Further measurments would lead to more specific analysis. The final part of the report gives different proposals for an upcoming work.

  • 14.
    Morad, Antoni
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Travancic, Faruk
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Control for Cold Rolling Mills2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report contains the details in a final research thesis work done rolling mill technology. The work is carried out at Heat Transfer located at Finspång. The main objective of this work is to evaluate thickness and flatness data from the profile to give an optimal start value for the pressure and force applied on the machine and the speed as well, so that the profiles produced, have the right thickness and best possible flatness.

    Thickness, start value for power, the degree of bending the profiles are set up and sent down to the control system.

    The report starts with a theory part describing the heating and cooling during process for aluminium profiles. A practical part describes experiments conducted on the rolling mill process under various conditions.

    The thesis work shows that the quality can be improved by rolling the slab in Aluminium industry by executing band tests and analysing graphs as 3-sigma, outward thickness and 3Dgraphs and its flatness.

  • 15.
    Eklund, Edvin
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies. Linköping University, The Institute of Technology.
    Brännskuggat fanér - en metodanalys2013Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    This thesis is about a part of the marquetrytechnique, scorching. Scorching is made by heating up something, put a veneer into the heated substance and make a controlled burning. This technique is old but still used today and have according to me great potential for development. In my work I wanted to give the scorching greater room then I earlier have seen. I wanted the scorching to be the dominant ingredient for a decorative element in a piece of furniture or an interior. This, I believe, is one way of making the art of marquetry more modern.

     

    In my report I have written about the history of scorching, both in terms of how often the technique has been used throughout history, but also for its development during time. This part of the thesis is mainly based upon studies of literature and some interviews.

     

    The biggest part of the thesis tries to consolidate a method for how to achieve a successful scorching. The criterion for successful is an equal gradient, repeatability and controlled length for the scorching. I have mainly experimented with exposuretime, exposuretemperature and different substances to heat up. During this experiments I have tried to define the best way to work. Several different woodspieces have been used but I have mainly worked with veneer of birch. During my work I have also tested to achieve new esthetical looks still mainly using the same technique. Changing materials to heat up and changing the way of applying the veneer. These parts of the thesis is based on empirical studies and with the report there are some physical samples describing my results.

  • 16.
    Lundh, Magnus
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Optimization and tuning of heat control2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Heat pumps have become even more popular when it’s about getting hot water and heat in our departments and villas. Before the heat pumps can be put into operation they have to go through some tests. IVT Industries AB performs the tests in different test rigs depending on the size or effect of the pump. The rig is divided in villapumps and real estate facilitypumps. Testrig F2 is one of the rigs where tests are performed on heatpumps in real estate facility’s. Doing adjustments of hot and cold water today, the IVT company uses cascades PIDcontrollers where the parameters has to be adjust on each tests. Optimization on the controllers have to adjust for the process time to become as short as possible but still there is a time demanded course of event because of the poor stabilitets in the controll and difficult adjustments of the parameters. With help of PID-controllers feedforward we achived.

    •Greater stabilitets

    •Faster process

    •Little adjustments

    •Lower energy consumption

    •Disturbance free regulation

  • 17.
    Rashid, Asim
    et al.
    Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Produktutveckling - Simulering och optimering.
    Strömberg, Niclas
    Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Produktutveckling - Simulering och optimering.
    Sequential simulation of thermal stresses in disc brakes for repeated braking2013In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 227, no 8, 919-929 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, an efficient sequential approach for simulating thermal stresses in brake discs for repeated braking is presented. First, a frictional heat analysis is performed by using an Eulerian formulation of the disc. Then, by using the temperature history from the first step of the sequence, a plasticity analysis with temperature dependent material data is performed in order to determine the corresponding thermal stresses. Three-dimensional geometries of a disc and a pad to a heavy truck are considered in the numerical simulations. The contact forces are computed at each time step taking the thermal deformations of the disc and pad into account. In such manner, the frictional heat power distribution will also be updated in each time step, which in turn will influence the development of heat bands. The plasticity model is taken to be the von Mises yield criterion with linear kinematic hardening, where both the hardening and the yield limit are temperature dependent. The results show that during hard braking, high compressive stresses are generated on the disc surface in the circumferential direction which cause yielding. But when the disc cools down, these compressive stresses transform to tensile residual stresses. For repeated hard braking when this kind of stress history is repeated, we also show that stress cycles with high amplitudes are developed which might generate low cycle fatigue cracks after a few braking cycles.

  • 18.
    Haglund, Johanna
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Heatloss through a concrete slab - a comparison of edge beams2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Of all the heat that is supplied in an average house in Sweden, about 15% of the heat leaks out through the foundation and the ground. A foundations task is to provide a solid base for a house while it should also keep the heat in the house. This report deals with the foundation concrete slab, where the focus is largely on comparing three different types of edge beams with respect to thermal bridges and energy consumption. This work has been performed in collaboration with Fiskarhedenvillan which is one of the largest house suppliers in Sweden. Fiskarhedenvillan are constantly working with reducing the energy consumption in their houses and now wish to obtain a better insight into how the choice of edge elements in the slab can affect this. To get a better understanding of how heat transfer works the report begins with a theoretical part. It deals with how heat conduction, radiation and convection works. The theoretical part also deals with foundations, thermal bridges, concrete slab and edge beams in general. The edge beam solutions mentioned in the report are:

    • U‐min grund, energy‐efficient

    • Leca edge element

    • Dorocell, L‐element

    Using the computer program HEAT2, a simulation of the edge beams has been made to obtain different values of thermal bridges. These values were then used to calculate how the choices of the edge beams affect the total energy consumption in a house

  • 19.
    Bexell, Jonas
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bjureus, Erik
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A study of energy exchange in earth air tubes2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As energy issues today are of great interest the writers of this report have done a research about an alternative to save energy by reducing the cost of preheating the outdoor air.

    By taking the outdoor air to the ventilation system via a pipe buried in the ground, you can preheat the outdoor air, which, in turn, could save energy. By doing this you do not have to bring as much energy to preheat the supply air, to get the desired supply air temperature. The report also explains if the earth air tubes are a good complement to the mechanical ventilation system with a heat exchanger.

    The report begins with describing briefly the history of ventilation systems in use today. It also describes the functions of the system and show to the reader how two of the installation layouts looks like.

    The writers using the project Daggkåpan in Linköping as a basis for the investigation and they also provide an alternative solution to the existing ventilation system.

    This report also demonstrate the factors that come into play to get as much energy exchange as possible, and what problems may arise with this type of complement to the ventilation system with a heat exchanger.

    Trough optimization of the earth air tubes and depending on which energy source is in use, you can actually save energy and by that also money. The factor that proved to bethe most significant for the energy exchange was the pipe length. Other factors such as trench depth, pipe diameter and the air flow has been shown to play a smaller role in how much energy you can save.

    Finally the report ends with the writers own reflections and a discussion based on the results.

  • 20.
    Lindbom, Erik
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Building preservation focusing on energy saving measures2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The project is based on a building, consisting of building timber, which was built in the early 1900s. The project aims to generate knowledge, guidelines and provide inspiration for how the building can be designed to serve as residence. The project also shows measures on how to maintain the building’s appearance from the time of construction and investigates how an acceptable thermal insulation can be obtained and how it effects the building’s character. The knowledge is primarily acquired from relevant literature and university courses in building- and urban planning and building physics.

    The results show a plan arrangement and propose measures for increased thermal insulation where the impact on the building’s cultural value is limited. The measures take account of old building techniques and materials and are largely reversible, which allowsna restoration to the original condition.

    The thermal insulating ability of the building’s enclosing element’s are calculated forthree cases, the building’s condition today and after the measures considered feasible without cultural value being lost. The final calculation is implemented in a version where the government authority requirements for new construction are achieved.

    The conclusion is that the building can be adapted to function as a residence. Measures to increase the thermal insulating capability can be implemented without affecting the  cultural values. The proposal reduces the building’s heat transfer coefficient by at least half of today’s performance. In order to fulfill the government authority requirement, measures have to be taken that may cause loss of character and cultural value.

  • 21.
    Fallhagen, Johanne
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Passivhus– framtidens boende?2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, the residential- and service sector accounts for approximately 40 percent of Sweden's energy usage. Therefore it is important to take measures for efficient use of energy, one way to do that is to reduce the energy used for heating. Energy consumption in a passive house is about a quarter of the consumption of a traditional house.

    Passive houses are well insulated and tight buildings that are largely heated by the energy already present in the house. The residents and their household appliances are very important sources of energy. Because of reduced heat loss, there is no need for radiators or underfloor heating. Since the passive house is so tightly built, all the ventilation occurs through the ventilation system and not through leaks in the construction. A heat exchanger for ventilation air helps to warm the fresh air from the already warm, used air. This way it recycles 85 percent of the heat energy.

    In general, it costs a few percent more to build a passive house than a traditional house, but the extra cost is repaid in just a few years due to the significantly lower energy costs. 3D-visualization is something that is becoming more common in the construction industry. It is not easy, especially not for the untrained eye, to understand a drawing in 2D. By creating a 3D-model of a building in the planning stage of a project, you can see how it will look like when it is built. I have created a 3D-model of a passive house in form of a terraced house. The visualization shows an alternative design of a typical flat with three rooms and a kitchen.

  • 22.
    Stenerfelt, Fredrik
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Relationships between Image Popularity and Color Emotions in Image Retrieval Systems2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Colors evoke various emotional feelings which can be described by semantic words such as excitement, harmony, energy, to mention a few. These feelings, evoked either by single- or combinations of colors, are called color emotions. We use previous developed models by Li Chen et al. aimed for estimating values describing color emotions (in this thesis activity, heat, weight and harmony). By calculating histograms, we adopt a previous proposed method by R. Lenz and M.Solli for applying three of the models on ordinary multicolor images. We propose a method using color histogram for applying the harmony model on multicolored images. Out of gathered user data from Picsearchs public search engine, popularity metric for images is approximated. On the basis of a database approximately containing 284 000 images, we analyze the relationship between derived color emotion parameters and approximated popularity values using visual and statistical methods. The experimental results show that individual relationships between different derived emotional values from specific key words and popularity values exist, however, no common relationships that hold for all key words was found.

  • 23.
    Gustafsson, Johan
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Witkowski, Sebastian
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Development of test environment for Thermia´s heat pumps2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Thermia Värme AB design and manufacture various heat pump systems for heating, hot water and cooling. This thesis report refers to an examination work carried out during the summer of 2006. The goal was to substitute the current way to test all functions of a heat pumps control system, with a more effective, less time and resource demanding solution.

    This work resulted in an attaché case with various electronics that simulate the original NTC-resistors that are used as sensors by the heat pumps control system. The electronics are constructed in such way that the company can choose to conduct the testing mechanically or with a computer using RS-232 communication protocol. This requirement was met by using digital potentiometers. To give the solution more flexibility two separate systems were constructed one that is directly connected with the heat pump system and one acting as a user interface. Communication between these systems was solved with microcontrollers using I 2C protocol.

  • 24.
    Nordlander, Johan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Data collection for an individual heat consumption measurement system using a Zigbee wireless network2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Individual heat/energy measurements have been a hot topic in Europe during the last 50 years, both for fair reasons and for energy saving reasons. The argument for using individual heat/energy measurements for fair reasons is that no one should pay more than he or she consumes no matter if the person lives in a rental apartment or in a house. Previous studies have shown that individual heat/energy measurements will lower the total energy consumed, when each tenant of a multi-apartment building has to pay for the actual amount of the consumed heat/energy individually.

    Unfortunately the installation cost of an individual heat/energy measurement system is considered to be high, so the economical arguments for installing this type of system in existing and new buildings have not been fullled. One reason for this is that until recently all of these systems used wired solutions. However the publication of the two wireless standards ZigBee and Zwave have opened new possibilities for creating entirely standardized wireless systems, reducing both the installation time and cost.

    The goal of this thesis work is to evaluate the possibilities for developing such a system based on the ZigBee standard. The work began with a study of the existing systems (hardware systems) available from some companies in Sweden (Brunata, Metrima, Siemens Building Technologies and Techem). This work also covers some communication protocols used (M-bus, BACnet, ZigBee) and dierent sensors (temperature, humidity, water consumption, and heat) used in an individual heat/energy measurement system.

    Based on this information a central data collection software server for windows has been developed. This together with a client application and a database server gives an entire software suite for data collection and data analysis of a ZigBee based heat/energy measurement system.

  • 25.
    Sammelin, Peter
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Energy effective houses2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is produced in corporation with Älvsbyhus representative in Östergötland. Älvsbyhus is for the moment the largest manufacturer of prefabricated detached timber houses in Sweden.

    A prognosis from the Swedish environmental protection agency and the Swedish energy agency suggests that the discharge of greenhouse gases will increase rapidly until 2020. The prognosis concludes that all energy use affects the environment to some extent and energy efficient buildings can contribute to a reduction of the greenhouse effect. The Swedish government are using economical and administrative instruments of control to guide the building companies and property owners. The Swedish building regulations concerning energy management has since 1 July 2006 been sharpened and the law of buildings energy performance will come into force in October 2006.

    The National Board of Housing, Building and Planning (BBR) has in the report “Piska och morot” concluded that it is impossible to estimate the socio economic potential of energy efficient buildings. The private economic potential can on the other hand lead to a decreased sensitivity to fluctuating energy prices. BBR’s report also suggests that the measurements could lead to an increased awareness and make energy efficiency to an important argument in project planning and marketing of buildings. Scientists working with energy matters are recommending a line of thought that means an increased focus on a reduction of energy losses through the building envelope. The building envelope should in other words have sufficient thermal insulation and protection against air leakage. The last step in the process would be to dimension the heating system after the remaining heating demand.

    The purpose with this study is to investigate how the building envelope on prefabricated houses of timber is constructed concerning rational use of energy. The results of the study are meant to lead to an increased knowledge about the technical level of our newly built houses and possible actions to decrease the energy use by changing the building envelope. The report begins with a theoretical section that explains the background and problems concerning energy effectiveness. The theoretical section is also meant to help the reader with an introduction in terminology, basic building physics and mechanisms that effects the heat requirements. The practical section of the report is a study of model houses from six of  Sweden’s largest manufacturers of detached timber houses.

    A simulation programme (ENORM 2004) has been used to calculate the thermal needs for the model houses. The results from the calculations are used to decide if the model houses are following present (BFS 2002:19) and future (BFS 2006:12) building regulations (BR). The present regulations concern the total heat transfer coefficient (F s = Um (W/m2K)) and future regulations concern the specific energy use (kWh/m 2 · year). The model houses will also be compared to identify differences in construction and calculation results that has an effect on the heat requirements. Houses that do not live up to the BR will be submitted to changes in the building envelope until they meet the regulations. To conclude the practical section of the report the model houses will be provided with qualities from low energy houses. The purpose is to determine how the heat requirement is effected with extreme changes in the building envelope.

    The results from the calculations (see table’s below) show that all model houses meet up to present building regulations. Future building regulations prescribe that Sweden will be divided into two climate zones separated on a level with the city of Karlstad. All model houses met up with the demands for the southern climate zone and none of the model houses met up with the demands for the northern zone. In the calculations Stockholm represents the southern zone and Luleå represents the northern zone.

     

  • 26.
    Karlson, Martin
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences.
    Assessing GIS-based indicator methodology for analyzing the physical vulnerability of water and sanitation infrastructure2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Climate related problems such as droughts, heat waves, increased levels of precipitation and storms threaten the functionality of several infrastructural systems. This thesis focus on infrastructure that provides for water and sanitation services because it has been identified as being particular at risk when the climate is changing. The identification and mapping of the vulnerability of a system can improve the prerequisites to choose more appropriate measures to facilitate the situation at hand. In this study a set of GIS based methodologies using indicators (simple and composite) of vulnerability are proposed and assessed. “Physical” vulnerability is used as a measure combining the intrinsic characteristics of a system and the climate related hazard resulting in a measure for physical vulnerability. GIS software is used to manage the spatial data sets and to combine the indicators into indexes of physical vulnerability. The assessed systems and related climate hazards are: - Water and sewage pipe network and an increased risk of pipe breakage due to increased frequencies of landslides and – An increased risk for ground and surface water supplies related to pollution from the point sources sewage infiltration and polluted ground”. The resulting GIS applications are tested on pilot areas located in the Stockholm region and GIS based sensitivity analyses are performed. The availability and accessibility of relevant digital spatial data is also assessed and discussed.

  • 27.
    Diószegi, Attila
    et al.
    Department of Mechanical Engineering/Component Technology, Jönköping University, Sweden.
    Hattel, Jesper
    Process Modelling Group, Department of Manufacturing Engineering, Technical University of Denmark, Lyngby, Denmark.
    Inverse thermal analysis method to study solidification in cast iron2004In: International Journal of Cast Metals Research, ISSN 1364-0461, Vol. 17, no 5, 311-318 p.Article in journal (Refereed)
    Abstract [en]

    Solidification modelling of cast metals is widely used to predict final properties in cast components. Accurate models necessitate good knowledge of the solidification behaviour. The present study includes a re-examination of the Fourier thermal analysis method. This involves an inverse numerical solution of a one-dimensional heat transfer problem connected to solidification of cast alloys. In the analysis, the relation between the thermal state and the fraction solid of the metal is evaluated by a numerical method. This method contains an iteration algorithm controlled by an under relaxation term to achieve a stable convergence. The heat transfer problem is reduced to one-dimension to promote the practical application of the method. Thermo-physical properties such as the volumetric heat capacity tabulated in the calculation are introduced as a function of solidifying phases. Experimental equipment was developed in order to investigate the thermal behaviour of the solidifying metal. Three cylindrically shaped cast samples surrounded by different cooling materials were introduced in the same mould allowing a common metallurgical background for samples solidifying at different cooling rates. The proposed inverse thermal analysis was tested on both experimental and simulated data.

  • 28.
    Nangunoori, Chetan Kumar
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, The Institute of Technology.
    Kumar Bhaskar, Ravichandra Kumar
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, The Institute of Technology.
    Parametric Ram Air Channel Model for Flow Optimization2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ram air channel or NACA channel is used to direct the ambient air for various purposes in an aircraft, such as pressurizing the cabin or as a coolant to heat exchangers and even more other applications like a cooling of the coolant. It is designed; such that it supplies the required amount of ambient air for various operations as mentioned, even aero-dynamical features should be taken into consideration while designing.

    In past, the developed prototypes are to be designed first and then experimented to optimize the design which gives accurate predictions and makes easy to understand the phenomenon occurring. These methods can lead to lot of waste in resources and time, in order to avoid these, some new mathematical methods have been implemented before finalizing the prototype which might save resources, time and minimize the possibility of having wrong outcomes. Some additional steps are included during calculation stage prior to the prototype stage; they are the computer aided simulations. These simulations can be as accurate as real time simulations and can bring closer to accuracy rate which is a needed prior to prototype stage.

    The aim is to design a tool chain for a Ram air channel which in turn is used to optimize the flow, then supplied to heat exchangers for cooling the hot refrigerant from the avionics systems. The requirements of the heat exchanger are decided on the applications it is used and the range of temperature to be cooled.

    In this study work, firstly estimate the size of the heat exchanger for the required performance, followed by the geometry of Ram air channel designing in CAD application so that it maintains the required amount of mass flow rate for the performance of heat exchanger. Finally these both components are implemented in simulation loop to iterate the designs of NACA channel in order to get the final model to optimize the flow for a heat exchanger.

     

  • 29.
    Sahlberg, Jörgen
    Swedish Meteorological and Hydrological Institute, Norrköping, Sweden.
    A Hydrodynamical Model for Calculating the Vertical Temperature Profile in Lakes During Cooling1983In: Nordic Hydrology, ISSN 0029-1277, E-ISSN 1996-9694, Vol. 14, no 4, 239-254 p.Article in journal (Refereed)
    Abstract [en]

    A one-dimensional hydrodynamical model is used for simulating the vertical temperature profile in a lake during cooling conditions. The vertical mixing rate is calculated by solving the equations for turbulent kinetic energy, k, and dissipation of energy, ε. The heat exchange between the water and atmosphere consists of the radiation fluxes, sensible and latent heat flux. Temperature measurements from Lake Väsman during November-December, 1981, were used in the verification study. The agreement between calculated and measured temperature profiles is very good. This indicates that both the mixing processes and the net heat flux are well described in the model.

  • 30.
    Sahlberg, Jörgen
    Swedish Meterological and Hydrological Institute, Norrköping, Sweden.
    Modelling the thermal regime of a lake during the winter season1988In: Cold Regions Science and Technology, ISSN 0165-232X, Vol. 15, no 2, 151-159 p.Article in journal (Refereed)
    Abstract [en]

    The thermal regime of a lake is investigated using both measured and numerically simulated data. The temperature measurements clearly demonstrate the importance of knowing the amount of short wave radiation that penetrates the ice-cover and the sediment heat flux from the lake bottom. However, the sediment/water coupling will not be treated in this study. In the numerical simulations a one-dimensional model is used, where the vertical exchange coefficient is calculated by a two-equation turbulence model. The meteorological forcing, which enters the model through the surface boundary conditions, is calculated on the basis of synoptic meterological observations every third hour. These boundary conditions are strongly affected by ice formation at the surface. Therefore, parameterizations of the initial ice formation and break-up and the ice growth and melting are included in the model. The amount of short wave radiation that reaches the ice/water interface is modelled in the following three steps: first, there is the snow or ice surface albedo, second, an absorption occurs in the upper 0.1 m of the ice and/or snow-cover, and third, the remaining radiation decays exponentially down to the ice/water interface.

    The modelled initial ice formation and break-up together with the ice growth and melting are verified against measurements with satisfactory results. Also the calculated water temperature increase and its vertical structure are well described by the model.

  • 31.
    Baas, Leo W.
    et al.
    Erasmus Centre for Sustainable Development and Management, Erasmus University Rotterdam, The Netherlands.
    Huisingh, Don
    Erasmus Centre for Sustainable Development and Management, Erasmus University Rotterdam, The Netherlands \ Institute for a Secure and Sustainable Environment, University of Tennessee, Knoxville, USA.
    The synergistic role of embeddedness and capabilities in industrial symbiosis: illustration based upon 12 years of experiences in the Rotterdam Harbour and Industry Complex2008In: Progress in Industrial Ecology, An International Journal, ISSN 1478-8764, Vol. 5, no 5-6, 399-421 p.Article in journal (Refereed)
    Abstract [en]

    Industrial Ecology (IE) is a known concept worldwide; however, its dissemination is not an easy process. Industrial routines are embedded in unsustainable practices that are difficult to change. The complexity and uncertainties of new concepts are often approached with ignorance and misperception. Nevertheless, the integration of economic, environmental and social dimensions in industrial activities is increasingly perceived as a necessary condition for a sustainable society. The paper reflects on the theories of embeddedness, capabilities and transformation to practical experiences of Industrial Symbiosis (IS) in the Rotterdam Harbour and Industry Complex (HIC).

  • 32.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering.
    Optimization of Building Retrofits in a Combined Heat and Power Network1992In: Energy, ISSN 0360-5442, Vol. 17, no 2, 161-171 p.Article in journal (Refereed)
  • 33.
    Gustafsson, E.
    et al.
    Combitech AB, P.O. Box 15042, 580 15 Linköping.
    Hofwing, Magnus
    Department of Mechanical Engineering Jönköping University P.O. Box 1026, 551 11 Jönköping.
    Strömberg, N.
    Department of Mechanical Engineering Jönköping University P.O. Box 1026, 551 11 Jönköping.
    Residual stresses in a stress lattice: experiments and finite element simulations2009In: Journal of Materials Processing Technology, ISSN 0924-0136, Vol. 209, no 9, 4320-4328 p.Article in journal (Refereed)
    Abstract [en]

    In this work, residual stresses in a stress lattice are studied. The residual stresses are both measured and simulated. The stress lattice is casted of low alloyed grey cast iron. In fact, nine similar lattices are casted and measured. The geometry of the lattice consists of three sections in parallel. The diameter of the two outer sections are thinner than the section in the middle. When the stress lattice cools down, this difference in geometry yields that the outer sections start to solidify and contract before the section in the middle. Finally, an equilibrium state, with tensile stresses in the middle and compressive stresses in the outer sections, is reached. The thermo-mechanical simulation of the experiments is performed by using Abaqus. The thermo-mechanical solidification is assumed to be uncoupled. First a thermal analysis, where the lattice is cooled down to room temperature, is performed. Latent heat is included in the analysis by letting the fraction of solid be a linear function of the temperature in the mushy zone. After the thermal analysis a quasi-static mechanical analysis is performed where the temperature history is considered to be the external force. A rate-independent J2-plasticity model with isotropic hardening is considered, where the material data depend on the temperature. Tensile tests are performed at room temperature, 200 °C, 400 °C, 600 ° C and 800 ° C in order to evaluate the Young’s modulus, the yield strength and the hardening accurate. In addition, the thermal expansion coefficient is evaluated for temperatures between room temperature and 1000 °C. The state of residual stresses is measured by cutting the midsection or the outer section. The corresponding elastic spring-back reveals the state of residual stresses. The measured stresses are compared to the numerical simulations. The simulations show good agreement with the results from the experiments.

  • 34.
    B M, Shiva Kumar
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems.
    Ramanujam, kathiravan
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems.
    Thermal Simulation of Hybrid Drive System2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Safety, performance and driving comforts are given high importance while developing modern day cars. All-Wheel Drive vehicles are exactly designed to fulfill such requirements. In modern times, human concern towards depleting fossil fuels and cognizance of ecological issues have led to new innovations in the field of Automotive engineering. One such outcome of the above process is the birth of electrical hybrid vehicles. The product under investigation is a combination of all wheel drive and hybrid system. A superior fuel economy can be achieved using hybrid system and optimized vehicle dynamic forces are accomplished by torque vectoring action which in turn provides All-Wheel Drive capabilities.

    Heat generation is inevitable whenever there is a conversion of energy from one form into another. In this master thesis investigation, a thermal simulation model for the product is built using 1D simulation tool AMESim and validation is done against the vehicle driving test data. AMESim tool was chosen for its proven track record related to vehicle thermal management. The vehicle CAN data are handled in MATLAB. In a nutshell, Simulation model accounts for heat generation sources, oil flow paths, power loss modeling and heat transfer phenomena.

    The final simulation model should be able to predict the transient temperature evolution in the rear drive when the speed and torque of motor is supplied as input. This simulation model can efficiently predict temperature patterns at various locations such as casing, motor inner parts as well as coolant at different places. Various driving cases were tried as input including harsh (high torque, low speed) ones. Simulation models like this helps Engineers in trying out new cooling strategies. Flow path optimization, flow rate, convection area, coolant pump controlling etc are the few variables worth mentioning in this regard.

  • 35.
    Feizaghaei, Roozbeh
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Improving climate performance of cement production: Developing an assessment framework and applying it to a CEMEX cement production cluster in Germany2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It is very likely that human being is contributing to the process of global warming. Industrial activities such as cement production are among the largest sources of human-induced greenhouse gas emissions. Therefore, there are ongoing efforts to reduce the CO2 emissions attributed to the cement production. In order to be able to systematically identify, classify, and evaluate the most effective, applicable, and feasible CO2 improvement measures, it is essential to have an assessment framework, which has an environmental management perspective. Such a framework should be able to cover the widest range of potential CO2 improvement measures, therefore it has to have a wide system perspective and consider all material, and energy flows within the industry as useful resources.

    The first part of this thesis uses the concepts of Industrial Ecology and Industrial Symbiosis as the supporting theoretical concepts for developing such assessment framework. The framework has semi-qualitative approach for assessing different measures and is developed in two parts: (1) generic and (2) site-specific assessment. The first part considers general aspects of the measures such as level of Industrial Symbiosis (i.e. complexity of business approach), the potential of each measure for reducing CO2 emissions, and their technological maturity. The second part assesses the feasibility of the measures regarding the conditions of a specific cement producing system. Aspects such as organizational applicability, technical and infrastructural applicability, and the existing level of implementation of each measure are considered.

    In the second part of this thesis, the developed framework is applied on a selected cement production system which is a cluster composed of three cement plants in Germany (owned by CEMEX) referred to as the Cluster West. The result of the assessment provides insights about the state-of-the-art of CO2 improvement measures in cement industry in general and also demonstrates which of these measures are most (or least) suited for development in the Cluster West. The production system of the Cluster West has effectively applied CO2 improvement measures in areas such as producing blended cement products, using alternative fuels (and renewable fuels) for clinker production. In addition, its clinker production (the Kollenbach plant that is part of the Cluster West) has relatively good energy efficiency. According to the results of the assessment, CO2 improvement measures such as co-generation (producing electricity from excess heat of the plant), using renewable fuels, using alternative materials for clinker production, and increasing the usage of alternative fuels are among the most applicable choices for further implementation.

  • 36.
    Sundbrandt, Markus
    Linköping University, Department of Electrical Engineering, Automatic Control.
    Control of a Ground Source Heat Pump using Hybrid Model Predictive Control2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis has been conducted at Bosch Thermoteknik AB and its aim is to develop a Model Predictive Control (MPC) controller for a ground source heat pump which minimizes the power consumption while being able to keep the inside air temperature and Domestic Hot Water (DHW) temperature within certain comfortintervals.

    First a model of the system is derived, since the system consists of both continuous and binary states a hybrid model is used. The MPC controller utilizes the model to predict the future states of the system, and by formulating an optimizationproblem an optimal control is achieved.

    The MPC controller is evaluated and compared to a conventional controller using simulations. After some tuning the MPC controller is capable of maintaining the inside air and DHW temperature at their reference levels without oscillating too much. The MPC controller’s general performance is quite similar to the conventional controller, but with a power consumption which is 1-3 % lower. A simulation using an inside air temperature reference which is lowered during the night is also conducted, it achieved a power consumption which was 7.5 % lower compared to a conventional controller.

  • 37.
    Buseva, Teiksma
    Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    The vulnerability of Latvia’s agriculture: Farm level response to climatic and non-climatic stimuli2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Agriculture is a climate sensitive sector whether it changes moderately and slowly or radicallyand rapidly. Many studies that focus on the vulnerability of agriculture, use climate scenariosand crop models to assess the potential impacts. This study seeks to identify (1) farmers‘awareness and perceptions of climate variability and change; (2) the types of adjustments theyhave made in their farming practices in response to these changes (farm responses, adaptivestrategies); and (3) other external factors (government policies, social, technological andeconomic conditions) that have significant impact on the farming activities.The results indicate that climate change and variability already have and will have mostlynegative impacts on agriculture. Prolonged dry spells and heat in the summer, less summerrain combined with higher temperatures, more heavy rainfall, more forest or grass fires andextreme weather: drought, flood, storms have been identified as highest climatic burdens toagriculture. An advanced start of the growing season is the the only truly positive change forthe majority of farmers. Apart from that several non-climatic factors were identified assignificant, among them political: high level of bureaucracy, lack of public trust in socialinstitutions, political instability; economical: incentives, for example tax exemption orreduction, access to subsidies and funds, economic growth and development, long-lastingeconomic recession; technological and infrastructural: access to advanced technologies,infrastructure and settlement development and poor road and railroad system; and social:population migration within Europa, ageing of population and population decrease. Thesesocio-economic factors play significant roles in overcoming the risks and building adaptivecapacity. This study shows that a variety of strategies and methods have been applied toreduce the vulnerability. Most often it is a farm level managerial decision, like, adjustedtiming of farm operations, changed crop variety and types, reduced number of livestock,improved technological base or increased income by off farm jobs.Finally we can conclude that even though individual farms have capacity to reducevulnerability, one must not underestimate the role of government and industry to decrease thedamages, take advantage of opportunities or cope with consequences. Farmer decision tomake changes in farming activities is rarely based on one risk alone.

  • 38.
    Hallberg, Björn
    Linköping University, Department of Management and Engineering, Energy Systems.
    Spillvärmeåtervinning ur kylvattensystemet ismältverket på Sapa Profiler AB i Sjunnen2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The smelting process at Sapa Profiler AB in Sjunnen generates large quantities of waste heat which is absorbed by the cooling water when the aluminum is cooled down. This paper is the result of a Master’s Degree Project aiming to present the conditions for recycling the waste heat. The cooling water absorbs the heat from the aluminum at an average rate of 600 kW and the paper shows that it can be used to replace electrical power consumption for heating the production plant’s facilities. The total savings potential comes to 464 000 SEK/year which represents a yearly reduction of 10-420 tons in CO2 emissions. Measures were taken already during the ongoing project in order to improve the possibilities of recycling the waste heat, which is suffering from discontinuous flows and low temperatures. In the paper a model is presented of how relatively high temperatures and continuous flows can be attained with the help of a warm water tank. Once he continuous flow is created, the waste heat can be exchanged to a separate flow which serves to transport the waste heat to the local heat distribution systems. Despite the significant savings potential, the  necessary investment of 3 650 000 SEK makes for a pay-back time of at least eight years.

  • 39.
    Hjersing, Charlotte
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hydrogen production in Escherichia coli: Genetic engineering of the formate hydrogenlyase complex2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biofuels that are renewable and environmentally benign constitute an important area of research, as the supply of fossil fuels decreases and the amount of green house gases in the atmosphere increases. Biohydrogen is not as well explored as other biofuels, but its properties render it a promising complement, as it is clean and can be used directly in fuel cells to generate electricity, the only waste products being water and heat. Hydrogenproducing microorganisms have the potential to be used to recycle industrial waste, such as carbohydrates from food manufacturing. Hence the cost of waste disposal could be reduced whilst biofuel is being produced through microbial processes.

    Escherichia coli is a well-known microorganism that produces hydrogen under fermentative conditions, through the conversion of formate to hydrogen gas and carbon dioxide, via an enzyme complex called formate hydrogenlyase (FHL). The complex is anchored to the inner cell membrane and consists of seven subunits: a formate dehydrogenase, a [Ni-Fe] hydrogenase, three electron carrier proteins, which together make up a large ‘hydrophilic domain’, and two integral membrane proteins (the ‘membrane domain’).

    Even though the entire bacterial genome is known, the FHL complex remains little understood and has proven difficult to isolate and characterise. During this project, a genetically modified strain producing only the hydrophilic domain of FHL was constructed, and the resultant sub-complex was purified. It was hoped that, if a stable and homogenous core complex could be isolated, it might be subjected to further analysis, such as elucidating the subunit stoichiometry and solving the structure.

    Furthermore, FHL is notoriously oxygen labile, which hampers its study and technological development. However, oxygen tolerance is a natural feature found in some other [Ni-Fe] hydrogenases, and recent research shows that this property is likely dependent on the presence of extra cysteine residues near an important metal cluster in the enzyme. These cysteines are not present in FHL and a complex that could be active in both aerobic and anaerobic conditions may be a useful tool in optimising microbial biohydrogen processes. Thus, three strains that each expressed a modified FHL variant carrying single Cysteine-for-Glycine substitutions were constructed. The modified FHL complexes proved to remain active in vivo, and can serve as the basis of genetically engineering oxygen tolerance into this important enzyme.

  • 40.
    Alfredsson, Sandra
    Linköping University, Department of Electrical Engineering, Vehicular Systems.
    Model Based Diagnosis of an Air Source Heat Pump2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of a heat pump is to control the temperature of an enclosed space. This is done by using heat exchange with a heat source, for example water, air, or ground. In the air source heat pump that has been studied during this master thesis, a refrigerant exchanges heat with the outdoor air and with a water distribution system.

    The heat pump is controlled through the circuit containing the refrigerant and it is therefore crucial that this circuit is functional. To ensure this, a diagnosis system has been created, to be able to detect and isolate sensor errors. The diagnosis system is based on mathematical models of the refrigerant circuit with its main components: a compressor, an expansion valve, a plate heat exchanger, an air heat exchanger, and a four-way valve. Data has been collected from temperature- and pressure sensors on an air source heat pump. The data has then been divided into data for model estimation and data for model validation. The models are used to create test quantities, which in turn are used by a diagnosis algorithm to determine whether an error has occurred or not.

    There are nine temperature sensors and two pressure sensors on the studied air source heat pump. Four fault modes have been investigated for each sensor: Stuck, Offset, Short circuit and Open circuit. The designed diagnosis system is able to detect all of the investigated error modes and isolate 40 out of 44 single errors. However, there is room for improvement by constructing more test quantities to detect errors and decouple more fault modes. To further develop the diagnosis system, the existing models can be improved and new models can be created.

  • 41.
    Söderström, Rikard
    Linköping University, Department of Electrical Engineering, Computer Vision.
    An early fire detection system through registration and analysis of waste station IR-images2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, an investigation was performed to find ways of differencing between firesand vehicles at waste stations in hope of removing vehicles as a source of error duringearly fire detection. The existing system makes use of a heat camera, which rotates in 48different angles (also known as zones) in a fixed position. If the heat is above a certainvalue within a zone the system sounds the fire alarm.The rotation of the camera results in an unwanted displacement between two successiveframes within the same zone. By use of image registration, this displacement wasremoved. After the registration of an image, segmentation was performed where coldobjects are eliminated as an error source. Lastly, an analysis was performed upon thewarm objects.At the end, it was proven that the image registration had been a successful improvementof the existing system. It was also shown that vehicles can, to some extent, beeliminated as an error source.

  • 42.
    Söderlund, Mikael
    Linköping University, Department of Management and Engineering, Energy Systems.
    Energieffektivisering och analysering av inomhusklimat genom simulering: IVT Värmepumpar, Tranås2010Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis has primarily been to improve the indoor climate in the building Greenhouse, belonging to the company IVT Värmepumpar in Tranås. The employees are experiencing problems with heat in the building's training facilities, specifically in the summer. An effort has also been made to develop measures that reduce building energy use in the form of electricity and heat.

    As the thesis was conducted during the autumn a simulation program was used to obtain a picture of the indoor climate during the summer. A model of the building was constructed in the simulation program, complete with ventilation and heating systems.

    To validate the model constructed, several measurements were taken during one week. The simulation model was calibrated against these measurements to mimic reality as much as possible. When the model was consistent with the measurements, simulations were performed in the summer to get a picture of the indoor climate and to detect any problems.

     

    Two different scenarios during the summer were constructed with different heat loads and time schedules. Scenario 1 tested how the indoor climate was affected by a large heat load in only one training facility, and, scenario 2 tested how the indoor climate was affected by a relatively large heat load in all training facilities. The results from the simulations showed problems with heat in the premises, albeit not to the extent of the employees previously stated experience.

    After analysis of the indoor climate, ventilation and heating systems, several actions were proposed. Most of these actions were implemented in the simulation model to see their potential and their effects in the summer. These proposals are either committed to improving the indoor climate or to reduce energy usage. These proposals are presented in Table 1 below (not included here, see the actual report) ; some proposals also have an estimated savings potential for total heating and the air handling unit’s electricity usage per year.

    Since this thesis might not solve the heat problems in the building, this report also includes suggestions on measures that may be required to reach a solution to the problem.

     

  • 43.
    Osbeck, Sofie
    Linköping University, Department of Management and Engineering, Energy Systems.
    Energieffektivisering vid ytbehandlingsprocesser: - en fallstudie av LaRay AB2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Med fokus på ökande energikostnader har en ny utmaning uppstått hos den svenska industrin – att minska energianvändningen. Den pulverlacktekniska ytbehandlingsindustrins energianvändning på 525 GWh per år motsvarar 0,4 % av den svenska industrins totala energianvändning. Denna bransch har länge haft ett intresse för miljöteknik och agerat framgångsrikt. Däremot har de inte prioriterat energisnåla investeringar. Anläggningarna drivs ofta av el och gasol vars kostnader förutspås öka med 50 – 60 % vid år 2020.

    För att undersöka energibesparingspotentialen inom den svenska pulverlacktekniska ytbehandlingsindustrin har civilingenjörsstudenten Sofie Osbeck från Linköpings universitet utfört en fallstudie hos företaget LaRay AB. Detta arbete har fortgått parallellt med civilingenjörsstudenten Charlotte Bergek från Chalmers tekniska högskola och hennes fallstudie hos QPC AB. Deras mål har varit att visa hur energianvändningen kan effektiviseras och minska med hjälp av energismarta lösningar.

    Arbetets genomförande delades in i fyra faser: fakta- och datainsamling, energikartläggning, åtgärdsberäkning och avslutningsvis benchmarking. Energikartläggningen visade att LaRay:s energianvändning är ungefär 1 GWh per år och fördelas på 77 % i produktionsprocesser och 23 % i stödprocesser. Med energieffektiva åtgärder kan användningen minska med ungefär 265 MWh per år. Tre fall av pinchtekniska analyser har arbetats fram med hänsyn till maximalt utnyttjande av befintlig värme, produktionsplanering samt investeringsmöjligheter. Dessa påvisar en potentiell energibesparing på ytterligare 121–198 MWh per år.

    Den totala årliga energibesparingen beräknas bli drygt 385 MWh, vilket är 38 % av dagens energianvändning. Energikostnaden minskar med ungefär 287 000 kr per år och investeringarnas payoff-tid varierar mellan 1,5 - 5 år. Resultaten från QPC visar en energibesparing på drygt 20 %. Baserat på dessa två fallstudier uppskattas en årlig energiminskning hos den svenska pulverlacktekniska ytbehandlingsindustrin på minst 25 %, vilket är likvärdigt med 130 GWh.

     

  • 44.
    Salomonsson, Stefan
    Linköping University, Department of Electrical Engineering, Information Coding.
    Simulation of Temperature Distribution in IR Camera Chip2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The thesis investigates the temperature distribution in the chip of an infrared camera caused by its read out integrated circuit. The heat from the read out circuits can cause distortions to the thermal image. Knowing the temperature gradient caused by internal heating, it will later be possible to correct the image by implementing algorithms subtracting temperature contribution from the read out integrated circuit.

    The simulated temperature distribution shows a temperature gradient along the edges of the matrix of active bolometers. There are also three hot spots at both the left and right edge of the matrix, caused by heat from the chip temperaturesensors and I/O pads. Heat from the chip temperature sensors also causes an uneven temperature profile in the column of reference pixels, possibly causing imperfections in the image at the levels of the sensors.

    Simulations of bolometer row biasing are carried out to get information about how biasing affects temperatures in neighbouring rows. The simulations show some row-to-row interference, but the thermal model suffers from having biasing heat inserted directly onto the top surface of the chip, as opposed to having heat originate from the bolometers. To get better simulation results describing the row biasing, a thermal model of the bolometers needs to be included.

    The results indicate a very small temperature increase in the active pixel array, with temperatures not exceeding ten millikelvin. Through comparisons with another similar simulation of the chip, there is reason to believe the simulated temperature increase is a bit low. The other simulation cannot be used to draw any conclusions about the distribution of temperature.

  • 45.
    Sammartano, Chiara
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Simulation of radio-frequency ablation of liver tumors: Development of a power regulation model and comparison with microwave ablation2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Local therapy with radiofrequency ablation (RFA) is an important method for treating liver tumors mostly in early stage, which has been increasingly used in recent years.

    RFA utilizes an RF current that is applied to the target tissue through an electrode connected with a power generator and percutaneously inserted into the tumor; the electrode power causes the tissue temperature rise required for destroying cancer cells.

    If RF thermal ablation entails numerous advantages - such as high repeatability of treatments, suitability for patients who can‟t undergo surgery, quick procedure and fast recovery -, there are still some inconveniences and difficulties coupled with this technique. One of these problems is the so called heat sink effects, resulting from the presence of large blood vessels close to the electrode tip.

    First, an overview is given of RFA physical background and heat transfer models followed by the improvement of a model of RF ablation in the liver. Second, special attention has been given to the mesh settings so that the simulation model could benefit from an appropriate mesh in terms of resolution and accuracy of the results obtained and in terms of reduced computational time. Then, a large part of the work has been dedicated to the development of a power regulation (PR) aiming at an optimization of the thermal treatment although the presence of large blood vessels in the ablation area and at an abatement of the number of residual tumors. Finally, a comparison work has been conducted between two different ablation modalities (RF versus MW) showing similarities and differences until the conclusion that currently the RFA treatment is the most suitable treatment for tumors in early stage, small and localized.

  • 46.
    Faghani, Farshad
    Linköping University, Department of Science and Technology, Physics and Electronics.
    Thermal conductivity Measurement of PEDOT:PSS by 3-omega Technique2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Conducting polymers (CP) have received great attention in both academic and industrial areas in recent years. They exhibit unique characteristics (electrical conductivity, solution processability, light weight and flexibility) which make them promising candidates for being used in many electronic applications. Recently, there is a renewed interest to consider those materials for thermoelectric generators that is for energy harvesting purposes. Therefore, it is of great importance to have in depth understanding of their thermal and electrical characteristics. In this diploma work, the thermal conductivity of PEDOT:PSS is investigated by applying 3-omega technique which is accounted for a transient method of measuring thermal conductivity and specific heat.

    To validate the measurement setup, two benchmark substrates with known properties are explored and the results for thermal conductivity are nicely in agreement with their actual values with a reasonable error percentage. All measurements are carried out inside a Cryogenic probe station with vacuum condition. Then a bulk scale of PEDOT:PSS with sufficient thickness is made and investigated. Although, it is a great challenge to make a thick layer of this polymer since it needs to be both solid state and has as smooth surface as possible for further gold deposition.

    The results display a thermal conductivity range between 0.20 and 0.25 (W.m-1.K-1) at room temperature which is a nice approximation of what has been reported so far. The discrepancy is mainly due to some uncertainty about the exact value of temperature coefficient of resistance (TCR) of the heater and also heat losses especially in case of heaters with larger surface area. Moreover, thermal conductivity of PEDOT:PSS is studied over a wide temperature band ranging from 223 - 373 K.

  • 47.
    Nadalina Jafabadi, Hossein
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics .
    Investigation of Film Cooling Strategies CFD versus Experiments -Potential for Using Reduced Models2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ability and efficiency of today’s gas turbine engines are highly dependent on development of cooling technologies, among which film cooling is one of the most important. Investigations have been conducted towards discovering different aspects of film cooling, utilizing both experiments and performing CFD simulations. Although, investigation by using CFD analysis is less expensive in general, the results obtained from CFD calculations should be validated by means of experimental results. In addition to validation, in cases like simulating a turbine vane, performing CFD simulations can be time consuming. Therefore, it is essential to find approaches that can reduce the computational cost while results are validated by experiments.

    This study has shown the potential for reduced models to be utilized for investigation of different aspects of film cooling by means of CFD at low turn-around time. This has been accomplished by first carrying out CFD simulations and experiments for an engine-like setting for a full vane. Then the computational domain is reduced in two steps where all results are compared with experiments including aerodynamic validation, heat transfer coefficient and film effectiveness. While the aerodynamic results are in close agreement with experiments, the heat transfer coefficient and film effectiveness results have also shown similarities within the expected range.

    Thus this study has shown that this approach can be very useful for e.g. early vane and film cooling design.

  • 48.
    Karlsson, Robin
    Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Anaerobic digestion of biological sludge from the pulp and paper industry2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for - and use of non-fossile fuels such as biogas have increased due to global warming, oil depletion and stricter environmental regulations. Organic wastes can be anaerobically digested in order to produce biogas, which can be utilized to generate heat or electricity. So far, little attention has been directed towards anaerobic digestion of organic wastes from the forest industry. Due to high sludge management costs and more rigorous environmental legislation, the demand for new and/or improved disposal methodologies has increased. Substrate treatment methods such as enzyme addition and ultrasound are of interest in order to make anaerobic digestion of organic wastes, e.g. biological sludge, economically feasible.

    The aim of this study is to evaluate if biological sludge from the pulp and paper industry can be used for methane production in anaerobic digestion and to investigate the effects of ultrasound pre-treatment and enzyme treatment.

    The aim of the study was accomplished by performing four batch experiments, during 67-110 days, and a six months laboratory-scale semi-continuous digestion experiment. Substrates were provided by a chemical and a mechanical paper mill, whereas Kemzymes® from Kemira and ultrasound equipment from Ultra Sonus were used for sludge treatment.

    The short term average accumulation of methane per added g VS rate increased both when ultrasound pre-treatment and enzyme treatment was applied in batch experiments. The enzyme treatment was considered to have a greater potential in larger scale and was consequently used in the semi-continuous digestion experiment. Positive effects of the treatment were however difficult to prove. Adapting the enzyme treatment to be more specific for the degradation of the sludge is recommended.

    It is possible that there are inhibitory interactions between ultrasound pre-treatment and enzyme treatment. 75% ultrasound pre-treatment is an alternative to complete pre-treatment and renders equivalent average accumulation of methane per added g VS. Storage of ultrasound pre-treated biological sludge at 4°C for six and 13 days does not affect the average accumulation of methane per added g VS. Enzyme treatment of biological sludge enhanced the average accumulation of methane per added g VS from indigenous material in the inoculum.

    It is likely that anaerobic digestion of biological sludge from the pulp and paper industry can render a stable biogas production. High viscosity and agitation problems were predominant in the semi-continuous digestion experiment and can be difficult to control in larger scale.

    The results from the semi-continuous digestion experiment are similar with those obtained from the batch experiments. The methane production rates in this study are lower (biological sludge from chemical pulp process) or higher (mechanical ditto) in comparison to those presented data by Puhakka et al. (1992). Different types of biological sludge were used and might explain the prevailing differences.

  • 49.
    Cardell, Lina
    Linköping University, The Tema Institute, Department of Water and Environmental Studies.
    Anaerobic digestion of pre-treated biological sludge from pulp and paper industry using heat, alkali and electroporation2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The biological sludge formed in the pulp and paper wastewater treatment constitutes a costlyproblem to dispose off due to poor dewaterability. It is often incinerated or used as soilconditioner improvement. By using anaerobic digestion of the biological sludge, thedewaterability can be increased. Thanks to the formation of biogas, the sludge volume isdecreased and energy can be recovered as methane. By pre-treating the sludge, the biogasproduction can be increased, making the anaerobic digestion more economically feasible.

    Eleven samples of biological sludges from six Swedish pulp and paper mills, chosen torepresent different types and sizes of mills available in Sweden, were pre-treated with alkali(NaOH, pH12), heat (80˚C, 1 hr) and electroporation (2000 pulses, 10 kV/cm). Initialmethane production rate and methane potential of all sludges and pre-treatments weredetermined using batch experiment. A combination of two sludges (from the same mill) pretreatedwith alkali and heat was further investigated in a semi-continuous digester experiment.

    The batch experiments showed that alkali pre-treatment had the greatest positive effect onmethane production. Heat treatment performed second best, whereas electroporation had no orlittle effect. Overall, pre-treatments increased the initial methane production rate, but withinsignificant effects on the methane potential. Heat pre-treatment showed no difference inbiogas production compared to the control in the semi-continuous digester experiment. Alkalitreatment was shown to inhibit biogas production and cause high accumulation of acetate. Itcould not be concluded whether it was an effect from hydroxide or sodium ion addition.Further analysis of the NaOH impact on floc structure, toxicity and bioavailability issuggested to determine the suitability of alkali-treated sludge for anaerobic digestion.

  • 50.
    Gröndal, Andreas
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems.
    Gillsäter, Ambjörn
    Linköping University, Department of Management and Engineering.
    Elenergibesparing i pumpsystem2010Independent thesis Basic level (university diploma), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    With rising electricity prices, it has become more important to increase efficiency of processes that use electricity. A place in the pulp and paper industry with high potential for saving of electric energy is pumping. In a previous project conducted by värmeforsk has an excel-based program to analyze systems of pumps and consumers been developed. The program is called PumpAnalys and by using this program it’s possible to visualize excessive and unnecessary pressure throttling in the system in a simple manner. The analyzed system is the so-called secondary heat system at Iggesunds bruk, which is used for recycling heat from turpentine and black liquor flows.

    The biggest savings have not been a result from PumpAnalys but from the low efficiency (28-65%) of the pumps included in the system. The diagram in Figure 1 shows the energy consumed in the system at present and after the three different efficiency increasing recommendations. The only difference between the present situation and suggestion 1 is that new pumps with better efficiencies have been installed instead of the old ones. In suggestion 2 and 3 the pressure differences over the pumps has been altered and more pumps have been installed.

    The difference between suggestions 1 and 2 is marginal, despite the extra booster pump. Two additional booster pumps in suggestion 3 cause additional savings. If efficiency suggestion 3 will be implemented it will save 612 MWh / year, representing about 50% of current energy use in the system. This saving is equivalent to approximately 305 000 SEK / year. However, pressure alteration only stands for about 131 MWh / year (about 20%) of savings while the improved efficiencies of pumps account for the rest. As a result of the additional cost of purchasing two additional booster pumps in suggestion three, the focus should be mainly on suggestion one.

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