umu.sePublications
Change search
Refine search result
1234567 101 - 150 of 363
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Gårdbro, Gustav
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Techno-economic modeling of the supply chain for torrefied biomass2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

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

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

  • 102.
    Gåsste, Filip
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av byggnad M7 i Umedalen: Energikartläggning med förslag till energieffektiviserande åtgärder ur en ekonomisk synvinkel2016Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

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

  • 103.
    Gåsste, Filip
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Uppföljning av energikartläggning: Hedbergska skolan i Sundsvall2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

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

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

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

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

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

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

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

  • 104.
    Hagman, Henrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Co-firing complex biomass in a CFB boiler: ash transformation, corrosion control and materials selection2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

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

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

    The results of this work include:

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

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

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

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

  • 105.
    Hagman, Henrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effects on a 50 MWth Circulating Fluidized-Bed Boiler Co-firing Animal Waste, Sludge, Residue Wood, Peat, and Forest Fuels2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 10, p. 6146-6158Article in journal (Refereed)
    Abstract [en]

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

  • 106.
    Hagman, Henrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boström, D.
    Lundberg, M.
    Backman, R.
    Alloy Degradation in a Co-firing Biomass CFB Vortex Finder Application at 880 °CManuscript (preprint) (Other academic)
  • 107.
    Hansson, Rasmus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energiutredning Brf Kruthornet2016Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
  • 108.
    Hassan, Mohamed Aidarus Nur Sheikh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energianalys av en tankstation: En förstudie av vilka energieffektiviserande åtgärder som kan göras på bensinstationer2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

     

    This study was carried out on behalf of Umeå municipality and Vindeln municipality together with Nenet (Norrbotten Energy Agency) as well as with the help of Exergi B(y)rån to carry out the  energy mapping at a petrol station. Many petrol stations use a lot of energy due to electricity, heating, cooling and lighting.

    Petrol stations are an important part of the infrastructure, a central hub of today’s society. By mapping their energy the stations can become more energy efficient, save money and also save the environment. By promoting their own work on energy efficiency and by having information about sustainable transportation at the station they could and would inspire their customers.

    The aim of this thesis was to investigate a petrol station’s energy usage and see which measures that can be taken for efficient energy use as well as arising interest among other petrol station owners. Calculation of cost-benefits and what actions that can be taken also been included. This work also gives an indication on how future petrol stations will look like according to the owners of the stations.

    The result of the survey shows a clear picture of a high energy use of 1126 kWh/m2 and therefore there is a great potential of taking energy efficiency measures. The petrol station is using cooling system due to the heat generated from all installations which is higher than the heat loss which occurs through the climate shell, ventilation losses and air leakage. By switching to LED lights in the store, in refrigerators and in different signs the generated internal heat will decrease. It is important that the ventilation system is correctly optimized to prevent unnecessary losses both in heat and economically. Some of the proposed measures for energy efficiency are to install twilight relay/dimmer for inside lighting, motion sensors in the storage, using temperature control for the heating cable in the ground and roof & gutter de-icing cables.

    A major operation that can be done is to build an airlock in front of the entrance for the front door as well as adding extra insulation to the attic.

    A major overview and renewal of the building installations is recommended, taking advantage of synergy in cooling and heating demands.

  • 109.
    Hasselrot, Rasmus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Investigation and evaluation of high-rise buildings in IDA ICE: A comparative study of energy efficient residential high-rise buildings in different climates2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is part of the major EU project EE-Highrise. The main objective of the EU project is to investigate high-rise buildings in different climates considering energy use, sustainability and cultural and economic differences in different countries. A demo high-rise building has been built in the capital of Slovenia.

    The purpose of this thesis was to build a model of the demo building in the simulation program IDA Indoor Climate and Environment. The model’s energy performance was then to be simulated in three different regions: Scandinavia, Central Europe and in the Mediterranean. Improvements to the climate shell and the ventilation system were to be examined and the results were then to be compared to European and Swedish Passive House certification schemes.

    A model was built in the simulation program IDA Indoor Climate and Environment according to the provided drawings of the demo building in Slovenia. Most of the building’s parameters were provided by the project group in Slovenia. When specific parameters were missing or difficult to motivate, standardized values were assumed. The model was modified into five cases: the base case, increased insulation of the external walls, improved glazing and frames for the windows, increased effective heat recovery efficiency and a combination of the energy saving measures. The model’s energy performance was then simulated at five different locations: Naples in Italy, Ljubljana in Slovenia, Malmo in southern Sweden, Karlstad in the middle of Sweden and Kiruna in the northern Sweden.

    When comparing the results to the requirements for the European Passive House certification, none of the investigated cases met the requirements due to a too large primary energy demand. However, if the requirement regarding the primary energy demand were to be disregarded, then the building in Slovenia would pass the requirements with an increased effective heat recovery efficiency for the ventilation system. Also the building in southern Sweden would pass the requirements with a combination of increased insulation for the external walls, improved windows and increased effective heat recovery efficiency.

    The Swedish Passive House certification would be fulfilled for the models in Malmo and Karlstad with an increased effective heat recovery efficiency, while the model in Kiruna did not pass the requirements. However, with a combination of the energy saving measures the model in Kiruna came very close to meeting the requirements.  

    The conclusion was that an increased effective heat recovery efficiency had the largest impact on the building’s space heating demand and that improving the windows increased the cooling demand in Naples by a large amount.

  • 110.
    Hasselstam, Jonas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Trafikverkets effektstyrningssystem - EFS 132 kV: Bidraget till minskade förluster2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The technological legacy from the early electrification of the Swedish railroads has resulted in a power grid with a lower grid frequency than the national power grid from which it is fed. Energy transfer between these power grids with different frequencies requires substations, adapting the grid frequency for the rail road power grid. For this purpose, a feeding power grid has been built, stretching across the country from Boden in the north to Tälle/Häggvik in the south.Power transfer in the Swedish power grid results in voltage angle differences which increase with increasing loads and transfer distance. These voltage angle differences are transferred from the power feeding substations to the rail road power grid, will in some extent cause loss of energy due to unwanted power flows from north to south.To minimize the losses due to this phenomenon, a power management system called EFS 132 kV has been developed and implemented. The system minimizes the unwanted power flows and controls the desired power flow for a good distribution of loads between the power feeding substations.This thesis investigates the extent of the transmission losses avoided due to the EFS 132 kV that coordinates the idling angles to a common reference point.The results indicate that EFS 132 kV affects the power flow, especially between the northern substations through an improved load distribution. The annual energy savings due to transfer losses are estimated at 24 GWh.The system’s power flows has been analyzed to detect weaknesses and losses and the opportunities and constraints facing a continued system improvement work.

  • 111. He, Hanbing
    et al.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, Sweden.
    Öhman, Marcus
    Time-Dependent Crack Layer Formation in Quartz Bed Particles during Fluidized Bed Combustion of Woody Biomass2017In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, no 2, p. 1672-1677Article in journal (Refereed)
    Abstract [en]

    Bed agglomeration during combustion and gasification of woody biomass fuels in quartz beds has been frequently studied, and chemical mechanisms responsible for bed agglomeration have been suggested: However, few studies have focused on the bed material deposition on walls, in cyclones, and return legs in fluidized bed combustion. Part of these bed material depositions originates from sticky fragments of alkali-rich silicates formed after crack formation in older quartz bed particles. The crack layer formation in quartz bed particles in fluidized bed combustion of woody biomass was therefore investigated by collecting bed material samples of different ages from full-scale bubbling and circulating fluidized bed facilities. Scanning electron microscopy/energy-dispersive spectroscopy was used to analyze the crack morphology and composition of the layer surrounding the cracks. For quartz bed particles with an age of some days, a crack in the quartz bed particle was observed in connection to the irregular interface between the inner layer and the core of the bed particle. The crack layer composition is similar for quartz particles with different ages and for samples taken from different fluidized bed techniques. Their composition is dominated by Si, K, Ca, and Na (except O). These crack layers become deeper, wider, and more common as bed particle age increases. The crack layers eventually connect with each other, and the whole quartz particle is transformed into smaller quartz cores surrounded by crack layers, which were observed in particles older than 1 week. From the characterization work, a crack formation process including three phases is proposed on the basis of the presumption that the initial crack layer formation resulted from the presence of induced cracks in the inner quartz bed particle layer. Fragmentation after the third phase is likely responsible for the formation of sticky alkali silicate deposit formation, and a weekly complete exchange of the bed is therefore recommended to avoid problematic deposits in combustion of woody-type biomass in fluidized bed combustion.

  • 112.
    Hedayati, Ali
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Lindgren, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Ash transformation during single-pellet combustion of agricultural biomass fuels – focus on K and P2018Conference paper (Refereed)
  • 113.
    Hedström, Anton
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ökad matarvattentemperatur vid biopannan Smurfit Kappa Piteå: Increased feedwater temperature at biomass boiler Smurfit Kappa Piteå2018Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    Smurfit Kappa Piteå is the largest kraftliner producer in Europe. At the mill they have five different steam producers and one of those is the biomass boiler, which is a steam boiler producing overheated steam at 120 bar and 520C. The purpose of this report is to investigate the possibilities to increase the feedwater temperature from today’s 180C to 210C. The consequences on the system are depending on the temperature in the different process stages and the process temperatures are therefore calculated via a method named The NTU-method which is a suitable method to analyze the heat transfer within an object when the ingoing and outgoing temperature are unknown. The feedwater is preheated with a heat exchanger that is heating the feedwater from 130C to 180C using steam with a pressure of 11 Bar. To increase the temperature to the desired  the approach is to install a complementary feedwater heater that uses steam with a pressure of 27 Bar. The new heater is supposed to heat the feedwater from 180C to 210C while the old heater takes the temperature from 130C to 180C. If the old heat exchanger approaches its end of life span it may have to be replaced with a new one with the same design data. One way to fulfill the required heating is to install one feedwater heater that takes the temperature from 130C to 180C using steam with a pressure of 11 Bar and in the next step install the second feedwater heater that takes the temperature from 180C to 210C using steam with a pressure of 27 Bar. There are two alternatives to installation of complementing high pressure heat exchanger. First alternative A is to install the second feedwater heat exchanger between the economizer and the steam dome. Second alternative B is to install the second feedwater heat exchanger between the already existent heat exchanger and the economizer. The consequence of the installation B is an increased energy loss due to the combustion gases while the consequence of installation A does not involve any increase in energy losses. Therefore, alternative A is wiser. However, whatever alternative that is chosen problem will arise since the temperature margin between the steam dome’s saturation temperature and incoming feedwater temperature needs to be at least 25C. This means that the largest possible pre-warming between the boiler’s workload 50-110% is 21C which not do apply to the whole interval. So, as it seems, the utilization of a second feedwater heat exchanger is not applicable over the whole interval of workloads. The increased feedwater temperature come with other consequences on the system. The whole system will be changed due to the increased temperature and it will affect the details. Some of the pipes must be replaced with new ones that fulfills the restrictions accompanying higher process temperatures. The purpose of the increased feedwater temperature is to increase the mass flow steam to the turbine. From calculations and the extraction-steam-consumption graph the increasing net power outcome from the turbine will increase with about 7.5% due to the increasing feedwater temperature. This will make the turbine produce even more electric energy and generate a bigger income to the factory. The investment cost is in total approximately 25MSEK, including replacing the old feedwater heater with a new one and installing a second feedwater heater. With a payback time of eight years and a life span of ten years it is necessary to question the economic potential of the installation. It provides a hint of the potential of the project. However, one should know that all numbers in this report are estimated from rough calculations. 

  • 114.
    Helin, Klas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Möjligheter och risker med miljöcertifieringssystemet Miljöbyggnad i en totalentreprenad: En ekonomisk optimering2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Environmental assessment for buildings is a means to reach the national environmental goals of Sweden. The construction and real estate sector accounts for a large part of Sweden's green house gas emissions and use of fuel, and environmental assessment tools can work as an incentive to improve on that. The Swedish tool Miljöbyggnad has grown considerably the last few years, and gives a solid option for the Swedish market. The tool assesses 16 indicators that are weighted together to give a building a final rating. The building can be rated Brons, Silver or Gold.

    The purpose of this study was to investigate and demonstrate risks and opportunities with the environmental assessment tool Miljöbyggnad, for both parties (the client and the contractor) in a design-build contract. This was accomplished by conducting a economic optimization of selected assessment tools indicators for a final rating of Silver, with the help of a reference building. From the result a methodology and general comprehension were acquired that can be applied in future construction projects. The aim of the study was to assess the reference building according to Miljöbyggnad's criteria. Then from the assessment present two optimal indicator configurations, one for the client and one for the contractor, that both yield a final grade of Silver.

    A model of the reference building was drawn using the architects drawings, and then built within an simulation software. Input for the simulations were mainly design instructions from the property owner of the reference building. Simulations and calculations to assess the building was conducted according to instructions from the Miljöbyggnad manual. From the result of the assessment, possibilities for optimization were investigated. A couple of actions were tested for their possibility to change the indicator grades, and differences in costs and pay-back times were calculated.

    The building was given a final grade of Miljöbyggnad Silver, where the indicator grades ranged from Bronze to Gold. In the optimal indicator configuration for the contractor, the grade of the indicator Heating demand was lowered from the original assessment. From the actions that were tested a saving opportunity was yielded from changing of the envelope, walls, roof and slab was worsened. In the optimal indicator configuration for the client, the grade of the indicator Energy use was increased and the grade of the indicator Energy sources was lowered. Saving opportunities were yielded from doing the same envelope changes but also improving windows, installing solar collectors and using Nordic electricity mix for appliance and building operation electricity.

    The conclusion from this study is that as a client to only demand a final grade for the building as part of the procurement is not recommended. A Miljöbyggnad certification with a design-build contract does not necessarily signify the most energy efficient building, there are distinct risks. Especially regarding the indicators within the area Energy in the assessment tool, and in practice the building's operating costs for energy. In a more controlled design-build contract with demands on specific indicators and even technical solutions, there are opportunities for the client to affect several indicator grades, as well as make cost savings.

  • 115.
    Hjalmarsson, Joakim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Uppdate and improvement of the mains selectivity in Edsbyn & Ovanåker.2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    A power failure can lead to major financial losses for companies and industries. To prevent unnecessary power outages, selectivity of the mains relay protection is established. This means that the malfunctioning part is disconnected from the working network. Inadequate selectivity of the mains relay protection can also lead to personal danger, the equipment takes unnecessary damage and a major part of the power grid is affected by a minor fault. Electricity distribution companies therefore have selective plans where a summary is made of the short circuit currents and disconnection times for the relay protections in their own grid.

    Edsbyns Elverk AB is a privately-owned electricity company, currently owned by approximately 600 shareholders. The business consists of production, sales and distribution of electricity in an efficient manner, within the county of Edsbyn and Ovanåker.

    Development and changes to the electric grid means that updates must be made for the existing selective plan. This may lead to changes for the relay current and time settings. These types of changes will be highlighted during the work and possible solutions will be presented. This work has been done as a degree project for a bachelor’s degree in the field of energy engineering.

    The work shows that improved selectivity can be achieved for three of the eight outgoing electrical compartments, that if relay protection settings are changed and updated according to current operating conditions. Recommendations have been presented in charts where the settings of time and current have been drawn. These have been made for two conditions, recommended times and currents as well as previous settings. The result can then be compared and motivate a change for the old relay settings.

  • 116.
    Holmgren, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Entrained flow studies on biomass fuel powder conversion and ash formation2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Reducing the global dependence on fossil fuels is of paramount importance in tackling the environmental challenges we face, not only tomorrow, but already today. Biomass offers a renewable supply of CO2-neutral raw material that can be converted into many different forms of fuels and valuable chemicals, making it a prime candidate for the technologies of tomorrow. However, the heterogeneous nature and distinctly different elemental composition of biomass compared to traditional fossil sources present new challenges to be solved. When it comes to thermochemical technologies, key issues concern fuel conversion efficiency, ash formation, ash/fuel interactions and ash/reactor material interactions.

    The objective of the present thesis was to provide new knowledge and insights into thermochemical fuel conversion, in particular its application in entrained flow technologies. A laboratory-scale reactor was constructed, evaluated and was used to study several aspects of high-temperature entrained flow biomass fuel conversion. Pulverized fuel particles from different biomass sources were used, and their physical and chemical interactions with the surrounding atmosphere, the concurrent ash element release, ash formation, and phase interactions were also studied in detail. In addition to the entrained flow reactor designed and constructed for this purpose, the main method for data collection was in situ optical studies of converting particles, either while entrained in the flow or when impacting upon surfaces. Elemental composition analysis of collected samples and gas analysis were also performed, allowing for a deeper understanding of ash element fractionation and interactions and thus explaining the observed properties of the resulting deposits or slag.

    The degree of conversion of fuels with very low ash content, such as stem wood, was well described and modeled by a novel method using optical data, offering a non-intrusive and non-destructive alternative to traditional techniques. Coupling computational fluid dynamics with optical data allowed for improved experimental data interpretation and provided improved accuracy for fuel particle residence time estimations, which is an important parameter when studying fast chemical reactions such as those taking place in reactors for entrained flow conditions. The results from studies on ash formation gave new insights into the feasibility of using dry-mixed K-rich additives for improving slag properties during gasification of Ca-rich and Si-rich fuels. Interpretations of the experimental results were supported by thermodynamic equilibrium calculations, and the conclusions highlight both possibilities and challenges in gasification with high fuel flexibility while at the same time producing a flowing slag. Applications and future implications are discussed, and new topics of interest are presented.

  • 117.
    Holmgren, Per
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Slag Formation during Entrained Flow Gasification: Silicon Rich Grass Fuel with KHCO3 Additive2018In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 10, p. 10720-10726Article in journal (Refereed)
    Abstract [en]

    Prediction of ash particle adherence to walls, melting, and flow properties are important for successful operation of slagging entrained flow gasifiers. In the present study, silicon-rich reed canary grass was gasified at 1000 and 1200 °C with solid KHCO3 added at 0, 1, or 5 wt % to evaluate the impact and efficiency of the dry mixed additive on slag properties. The fuel particles collided with an angled flat impact probe inside the hot reactor, constructed to allow for particle image velocimetry close to the surface of the probe. Ash deposit layer buildup was studied in situ as well as ash particle shape, size, and velocity as they impacted on the probe surface. The ash deposits were analyzed using scanning electron microscopy–energy-dispersive X-ray spectroscopy, giving detailed information on morphology and elemental composition. Results were compared to thermodynamic equilibrium calculations for phase composition and viscosity. The experimental observations (slag melting, flow properties, and composition) were in good qualitative agreement with the theoretical predictions. Accordingly, at 1000 °C, no or partial melts were observed depending upon the potassium/silicon ratio; instead, high amounts of additive and a temperature of at least 1200 °C were needed to create a flowing melt.

  • 118.
    Holmgren, Per
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå Universitet.
    Carlborg, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå Universitet.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå Universitet.
    Slag Formation During Entrained Flow Gasification: Calcium Rich Bark Fuel with KHCO3 AdditiveManuscript (preprint) (Other academic)
    Abstract [en]

    Managing slag properties is of utmost importance for successful operation of entrained flow gasifiers. The present study details some aspects of slag formed from a softwood bark fuel, and especially the situation with only small amounts of mineral contaminants, meaning composition is shifted from Si- towards P-dominated ash. Wood bark with and without KHCO3 additive was gasified between 850 °C and 1300 °C at O2 stoichiometric ratio (λ) 0.6 to study the resulting ash properties and the influence of the additive. The ash particles collided with a flat impact probe inside the hot reactor, with particle impact angles varied between 90° to 30°. The reactor and probe were constructed to allow for long-distance microscope data collection close to the surface of the probe. In situ PIV and SEM-EDS of deposit samples from lab scale entrained flow gasification experiments were used for evaluation, while XRD was used to characterize carbonates. High potassium release was found but numerous spherical ash particles indicated lower ash melting temperatures than expected from the bulk ash composition. These new findings propose a mechanism for melt formations involving carbonates rich in potassium and phosphorous, followed by K-release and calcination leading to solidification.

  • 119.
    Holmlund, Karolina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Okonventionella lösningar på solcellsproblematiken: Unconventional solutions of problems caused by photovoltaic cell2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Det svenska elnätet har i dagsläget en mycket hög leveranssäkerhet, men står inför en stor utmaning i och med decentraliseringen av elproduktionen. Allt fler privatpersoner och företag upptäcker fördelarna med att producera egen el i direkt anslutning till fastigheten. När solcellsanläggningar ansluts till elnätet ställs nya krav på nätet och dess distributionsmöjligheter. Främst skapas överspänningar när el distribueras från solcellsanläggningarna och ut på lågspänningsnätet. Detta examensarbete utreder vilka okonventionella lösningar som är tekniskt möjliga att implementera på marknaden för att möta den nya problematiken. Projektet innefattar en jämförelse mellan de okonventionella lösningarna och de två lösningar som rekommenderas i dagsläget, batterilager och ombyggnationer av det befintliga elnätet.

    För att besvara projektets frågeställningar har en litteraturrapport skrivits med grund i gällande regelverk, genomförda projekt och nya tankar och idéer från kunniga inom området. För- och nackdelar med de två rekommenderade lösningarna sammanställdes utifrån befintlig teknik innan de okonventionella lösningarna utreddes. Delvis saknas ekonomiska jämförelser för alla okonventionella lösningar, vilket beror på bristande tekniska specifikationer eller idéer utan praktisk grund. Projektet är avgränsat till landsbygdsnätet eftersom det i regel är svagare än stadsnätet och de nätanslutna solcellsanläggningarna påverkar i större utsträckning de svagare näten.

    Fem okonventionella lösningar omnämns i rapporten. Den förstnämnda lösningen berör växelriktarna som finns i anslutning till solcellsmodulerna. Där det främst handlar om ett begränsat effektuttag eller produktion och konsumtion av reaktiv effekt. Därefter utreds vilken potential smarta hem och smarta elnät har. Konstateras att det kräver höga implementeringskostnader och omfattande ombyggnationer av elnät och fastigheter. Den tredje lösningen berör huruvida lindningskopplarna vid transformatorerna kan användas för att lösa den nämnda problematiken. Den fjärde tänkbara lösning som i dagsläget redan testas ute på elnätet är 1 kV-system som kortfattat går ut på att höja spänningen från 0,4 kV till 1 kV. Det medför en ökad tolerans mot överspänningar och öka överföringskapaciteten på nätet. Slutligen lyfts idéer gällande spänningsreglering på lågspänningsnätet med kraftelektronik.

    De nämnda lösningarna har tekniskt sett potential att etableras på marknaden, men i flera fall blir implementeringskostnaderna höga. Dessa lösningar skulle fördelaktigt testas på elnätet för att utvärdera i vilken utsträckning de kan lösa problematiken och vilka konsekvenser det medför.

    The full text will be freely available from 2020-01-01 00:00
  • 120.
    Hussein, Gomil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energiförluster i eternitkulvert och flödeskartläggning av Kramfors fjärrvärmenät2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Kramfors heating network was built in the 1960s. Culverts that were used at the time were composed of a pipe of steel, asbestos cement (eternite) and polyurethane foam (PUR foam) blown with chlorofluorocarbons gas (CFC gas) as insulation. The expansion of district heating began during the 1970s and 1980s and even more in 1990s. One problem that may arise during expansion of a district heating network is the risk of overloading the main pipes of the heating network if they were designed for lower flows.

    The aim of this work is to calculate energy losses from eternite culvert over a twelve months period to then compare losses, both financially and from an energy perspective, with today culvert as a reference. Even a flow mapping on the network will be presented for the month of December 2012 as a basis for future growth of subscriber stations.

    Eternit culvert energy losses was more than twice as much as the losses with modern culvert for the reason that the heat conductivity in the eternit culvert is about 3 times higher compared with modern culverts.

    If Neova has to supply the entire investment, the analysis shows that if the price of the fuel and the energy losses is constant throughout the payoff time it would take 104 years for the investment to pay off.

  • 121.
    Häggkvist, Ylva
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering i Stigbygeln: En förstudie2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Diös fastigheter is Northern Sweden's largest private real estate company. The bulk of the company's holdings constists of centrally located retail, industrial and office buildings, 23 of which are located in Umeå. Diös fastigheter works continuosly to decrease energy consumption in their building stock. One part of this work is to pursue the Greenbuildning environmental certification for buildings. This paper examines a building named Stigbygeln 2, situated on Dragonfältet i Umeå, currently rented by the logistics company PostNord. The energy consumption last year was approximately 290 kWh per square meter. This paper examines the reasons for the high energy consumption and which measures to increase energy-efficiency yield the largest energy-savings at the lowest cost.

     

    At the present time Stigbygeln 2 is connected to the municipal district heating network, and distric heating is utilized as heating source to warm the inlet air of the ventilation system, which in turn warms a significant portion of the facilities found in the building. Heating of supply air constitutes 85% of the total heat load, and there is no system for heat recovery.

     

    Stigbygeln has been constructed in the simulation tool IDA ICE in accordance with known conditions, and different measures to increase efficiency have been investigated, individually as well as combined. Through LCC analysis, savings resulting from decreased energy consumption have been weighed against the initial investment cost and the operational cost.

     

    The result shows that a switch to FXT ventilation would yield the largest energy savings, 57%, and that this is also the financially most advantageous route. Conversion to geothermal heating reduces energy consumption by 37%, but is not economically viable. A swith to LED lighting is a measure that yields a good return on the investment cost and lowers energy consumption by 7%. The savings are greatest when a change of ventilation system is combined with a change to LED lighting.

  • 122.
    Hägglund, Hampus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektiviseringsförslag på Knorthems avloppsreningsverk: En förstudie till förslag som kan leda till minskad energianvändning på Knorthems avloppsreningsverk2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wastewater treatment plants fulfill an important function in a society adapted to eco-cycle. The water used and polluted by human must be purified from substances that lead to eutrophication, oxygen deficiency and littering in our seas and oceans. The water cleaning process is an energy guzzler in our society. Many plants are built in the 70s and 80s and old equipment is still used. A more efficient process means that less external energy in the form of heat and electricity need to be bought, which is a cost saving that can make investments viable for the long term. It can also be seen in line with EU environmental work on 20% more efficient energy use by 2020.

    The work for this report is made on the Knorthems wastewater treatment plant in Central Örnsköldsvik, where water from Örnsköldsvik Centre is purified. The cleaning process can be divided into two stages. The first is to purify the water so it can be discharged into Örnsköldsviksfjärden, and the second step is to digest the sludge from the water purification. The digestion process produces biogas fired to heat up sludge in the digestion tank and keep it at 37.5℃ and heat up the buildings.

    The purpose of this work has been to develop suggestions how the energy use can be reduced at the treatment plant. To get a picture of the energy distribution, a theoretical survey is made over electricity need in the process and building, as well as the heating needs of buildings and process. Because of the limited time, only the major electricity users were accurately calculated and analyzed. Other equipment has been checked and electricity users effect and operation time have been used in the estimation of used energy. The warming goes to premises for the staff and process, as well as heating and keep the sludge in the digestion tank warm. The heat flow for warming the buildings was measured and an equation was developed to determine the relationship between the outside temperature and heating requirement. Calculations of energy used for heating of the buildings could then be done. The digestion tanks heating could be calculated based on the fed of sludge and the heat losses through the tank. By demand a construction model of the digestion tanks the heat losses could be calculated.

    The results of the energy survey has been used as a basis for further work with suggestions for changes that will lead to reduced energy use. The result of the suggestions includes both simple changes to adjust the operation of ventilation and inspection of the radiators, to bigger suggestions such as heat exchange between sludges and the renovation of the aeration basin air system.

    During the work many assumptions and simplifications have been made to achieve the results. Only a few measurements have been executed during the very short periods of time and then served as the basis to calculate the energy in one year. This makes that the presented values are rough theoretical calculations and should be used as an indication of where further and deeper works can be done.

  • 123.
    Häggström, Gustav
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Evaluation of the potential for co-gasification of black liquor and biofuel by-products: An experimental study of mixing and char reactivity2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The increased use of fossil fuels during the last centuries has caused elevated levels of carbon dioxide in the atmosphere. There is significant evidence that this is the cause of global warming. To mitigate the global warming, measures has to be taken to use renewable fuels and make processes more efficient.

    Catalytic gasification and downstream upgrading of synthesis gas is a promising technology for biofuel production, where previous research in black liquor gasification is currently expanding into a wider fuel feedstock.

    This work focuses on co-gasification of black liquor and by-products from other biofuel production technologies. The interesting by-products were crude glycerol from biodiesel production and spruce fermentation residue from ethanol production. The main goals were to study if the fuels can mix homogeneously and study the char reactivity. CO2 char gasification for mixtures of black liquor and glycerol or fermentation residue respectively was studied using thermogravimetric analysis (TGA) for four temperatures between 750°C and 900°C.

    The results show that glycerol can be mixed in all proportions with black liquor and indicate that the char reactivity is unchanged. The sustained char reactivity for blends is attributed to the volatility of glycerol. The fermentation residue does not produce a homogeneous mixture with black liquor and the char is less reactive.

    More studies should be performed to further elucidate the validity of the results.

  • 124.
    Häggström, Gustav
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Wagner, Katharina
    Bioenergy 2020+ GmbH, Wienerstraße 49, A-7540 Güssing, AustriaInstitute of Chemical, Environmental & Bioscience Engineering, TU Wien, Getreidemarkt 9/166, A-1060 Vienna, Austria.
    Kuba, Matthias
    Bioenergy 2020+ GmbH, Wienerstraße 49, A-7540 Güssing, AustriaInstitute of Chemical, Environmental & Bioscience Engineering, TU Wien, Getreidemarkt 9/166, A-1060 Vienna, Austria.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Effect on P-mineralization in fluidized bed combustion of chicken litter with wheat straw and bark residues2018Conference paper (Refereed)
  • 125.
    Häreskog, Linnea
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Integration of hydrothermal processes on a forest-based biorefinery site2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The pulp and paper industry (PPI) is a business that produce large amounts of residues annually. Besides bark, large quantities of sludge are produced from the various parts of the industrial process. The sludge that comes from the biological wastewater purification process is denoted biosludge and is known as a particularly problematic waste product. It is of interest to reduce the amount of sludge from the PPI or to find new ways of handling the produced sludge. The common way to treat the PPI sludge is by incineration in the site’s bark boiler. The material is however difficult to dewater and often does more harm than good in the boilers. Different technologies to try and dewater the sludge further have been investigated previously, one that has recently been noted is hydrothermal treatment. The technology described in this thesis work is called hydrothermal carbonization (HTC) which uses water as a reaction media to turn the sludge into a coal-like material called hydrochar. The hydrochar has a higher heating value than the initial sludge and is more hydrophobic which makes it easier to dewater.

    This Master’s thesis describes the process technologies of the HTC process and presents some of the recent work done within the area. The properties of different residues from the PPI are presented before the integration of an HTC process on the biorefinery site in Domsjö, Sweden is discussed using previously published articles. A survey concerning sludge from industries within a 500 km range of the Domsjö biorefinery site is made to investigate whether residual streams similar to the ones at the Domsjö site are available in the vicinity.

    The results show that an HTC process demands energy in the form of steam and/or electricity. A previously made pinch and total site analysis show that the most accessible steam at the Domsjö biorefinery site, that most appliances and process steps uses, is at 7 bars. There are also steam levels of 20 and 32 bar in the area, which is within the range an HTC plant requires. The HTC process water demands further treatment which puts an extra stress on the already existing water purification process. The Domsjö biorefinery site produces 6000 tonnes of biosludge per year. Several HTC companies produce units that normally treat 20000-50000 tonnes of sludge per year, which indicates that additional sludge could be added to reach full capacity. The survey shows that there are similar materials available in the surroundings. It is concluded that further investigations concerning the sludge materials must be made before real implementation consequences can be calculated.

  • 126.
    Högberg, Jesper
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energisimulering för ett flerbostadshus: Undersökning av energianvändning med hjälp av IDA ICE2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In recent years, it has been found that a greater understanding of the existing building stock's energy use has become increasingly important and that it must be made more energy efficient if we are to achieve all our set goals. If you look at today's energy use, the housing and services sector accounts for about 40% of Sweden's total energy consumption. If you look specifically at the multi-dwelling houses, these constitute approximately 30% of the energy use. Therefore, it may be important to get information about what measures can be taken to reduce energy use. 

    The purpose of the project is to produce proposals for measures that reduce the energy consumption of a multi-dwelling house located in Umea built in 2006.

    The energy simulation program IDA ICE has been chosen to build a model of the multi dwelling house. When the building has been created in the program, the simulated apartment house will be compared with a real energy declaration that was carried out in 2009, this is done because it is a strong source that makes the project more credible. When the energy declaration values ​​and the simulated values ​​match, the project goes on to find different energy-efficient measures. The energy efficiency that will be simulated in IDA ICE is the replacement of existing ventilation system to an FTX system with higher heat recovery, some other energy efficiency proposals that will be made are the lowering of the indoor temperature from 22 degrees Celsius to 20, it will also be tested to additionally insulate the outer walls with mineral wool. and to replace existing windows with a better U-value. The solution that turns out to be good is to replace the existing FTX system with heat pipe against an FTX system with rotary heat exchanger with an efficiency of 85% then you will save 76 270 kWh or 17,4 kWh/m2 this will be a saving of 50 338 SEK/year.

  • 127.
    Högström, Isak
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förskolan Hoppet2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete uppförts i samarbete med VVS konsulterna Skellefteå. Det behandlar en jämförelse av ventilationssystem på en förskola på Sofiehem som är planerad att stå klar 2017.

    Syftet med arbetet är att undersöka om det går att spara energi och kostnader genom att använda sig av en styrd ventilation istället för konstantflödesventilation som är planerad. Eftersom det är dyrare att investera i en styrd ventilation kommer det också undersöka återbetalningstiden för den investeringen.

    För att göra undersökningarna har programmet IDA ICE använts för att rita upp en modell av byggnaden och simulera dess energianvändning för att senare jämföra resultaten och se skillnaderna mellan de olika ventilationssystemen. Ett förslag har framtagits på hur ventilationskanalerna kan dras om för att få plats med en installation av VAV-spjäll med tillhörande ljuddämpare.

    Resultatet från simuleringarna gav att den totala energianvändningen sjönk med 18 % med styrd ventilation och det minskade den totala energiförbrukningen med 22 000 kWh/år. Av den minskningen stod fläktens energianvändning för 46 % och uppvärmningen via fjärrvärme för 54 %.

    Investeringen för styrd ventilation jämfört med konstantflödes ventilation är 168 000 kr mer och får utifrån beräkningarna i detta arbete en återbetalningstid på 12 år. Livslängden på ventilationssystemet antas vara 25-30 år.

  • 128.
    Jakobsson, Alina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Solvärme till Östersunds Rehabcentrums terapibad: Förstudie av förutsättningar för, - och lönsamhet med, solfångare för att värma terapibadet2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report treats whether it is viable to invest in solar heating to heat the therapy pool at Östersunds Rehabcentrum. The rehab center is owned by the county council of Jämtland and is located on Solliden in Östersund city. The solar heating where supposed to be a complement to the district heating that was heating the pool in the current situation. Later, it however showed that this was not the case. The pool is currently being heated by a radiator circuit that is being heated by the district heating. The temperature in this circuit is however controlled by the outside temperature. If the outside temperature is increased sufficiently, there is no need to heat the building with the radiators. What happens then is that the temperature in the circuit might fall so it no longer can heat the pool. When this happens, an electric heater of 15 kW kicks in to heat the pool instead. Studies of the control signal to this electrical heater show that it heats the pool approximately from the middle of April until the beginning of October. Calculations show that the electrical heating stands for 72 % of the annual cost to heat the pool, even though it heats the pool during half of its running time.

    Because of this, three options for investment where calculated based on the wishes of the client. One option is to connect the pool directly to the heat source, which is district heating, to eliminate the electric heating. The second option is to install solar heating after the pool has been connected directly to the heat source. The third option is to keep the current connection of the pool and only install solar heating. The last option is investigated to compare the viability in solar heating depending on current heat source. The solar heating systems have been dimensioned to cover the pools energy demand during optimum conditions, with a working temperature in the solar collectors of 50°C. This is to avoid problems with not having use of the energy from the solar collectors during optimum conditions. Four different solar collectors are compared, two flat plated and two collectors with vacuum pipes.

    To determine the viability of the investments their pay-back time and present value have been calculated. The life-span of the solar collectors is approximated to 40 years and the cost of capital is 4 %. The annual increase in energy cost for electricity and district heating is calculated to 4 and 3 %, respectively. There is a possibility to receive financial support for some investments, this has however not been taken into account in the calculations.

    The results show that the most viable investment is to connect the pool directly to the district heating. The pay-back time is only one year and the annual cost for heating the pool becomes less than half of what it is today. The profit after 40 years becomes 1,6 million kr. Investing in solar heating that replaces the district heating proves not viable during the 40 years period. If the connection to the radiator circuit is retained, all of the solar collectors become viable. Most viable in this case is the solar collector 24-ST, with a pay-back time of 16 years and a profit of 1,3 million kr during the calculation time.

  • 129.
    Jakobsson, Anton
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energibesparing i industrilokal: En IDA ICE studie2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Reducing the energy consumption in older buildings is growing to be more important by each passing day as the cost of energy rises and political strides are made to limit the amount of energy used for various purposes. To optimize the use of energy in a building can be described as getting the same end result with a lower amount of spent energy, for the user this is an economic victory as he doesn’t have to spend as much money on heating his building while society gains a reduced impact on the environment and climate. In this thesis that you hold in your hands I have investigated an industrial building located in Teg, Umeå where I utilized the simulation software IDA ICE to simulate the buildings energy usage and the effects of various energy optimization/saving measures if implemented. The measures simulated are: Additional insulation for walls and roof, the switch to a ventilation system with a heat recovery unit, switching to well insulated windows, and switching the doors and garage doors to well insulated units.

    The work has mostly been done through studies of literature and IDA ICE where a model of the building has been constructed according to the specifications of the real world counterpart. The results from the various simulations are then compared with each other and the reference case.

    The results showed that all energy saving measures would result in a lowered use of energy. The biggest saving was gained from the changing out the ventilation system which resulted in a 49,3 % reduction whilst changing windows only resulted in a 0,7 % reduction.

  • 130.
    Johannesson, Daniel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    CO2 and Cost Impact of Pre-and Post shift of Residential Electric Loads2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Royal Seaport project, which is a project in the Clinton Climate Initiative, develops a new, sustainable city area in Stockholm and aims to reduce the greenhouse gas emissions, using pre- and post load shifting methods to reduce the peak electricity load. The Active House, that is one work package in the Royal Seaport project, is a residential building that is equipped with systems for automated demand response, such as smart appliances and electricity storage, and also local photovoltaic power and charging poles for electric vehicles.

    The thesis investigates if pre- and post shifting electricity load will reduce greenhouse gas emissions and electricity cost for the residents in the Active House. The greenhouse gas emissions are investigated for three Clinton Climate Initiative cities, Stockholm, London and San Francisco to further calculate the pre- and post shifting impacts of greenhouse gas emissions and electricity cost.

    A simulation tool based on statistics of the power systems is developed, to investigate the greenhouse gas emissions from electricity production and the simulator is used to solve the research questions in the thesis. The simulator calculates an hourly greenhouse gas intensity distribution during the day and the results are used to observe differences between seasons and countries. The electricity loads of the households in the Active House are also investigated to determine the peak electricity loads to be able to dimension the photovoltaic power system and electricity storage.

    Some of the most important results and conclusions in the thesis are:

    The relationship between the greenhouse gas emissions and the electricity production determined, in most cases the greenhouse gas intensity distribution has a similar shape as the consumption and electricity price.

    The photovoltaic power system will be able to provide 30 % of the fixed building electricity load. The electricity storage could be charged during night, when the greenhouse gas intensity is low, or when the photovoltaic power system generates surplus electricity that otherwise would be given away to the utility grid.

    The dimensions of the electricity storage are cycled one time during the day and calculated to be 205 kWh to be able to pre shift an electricity load of 114 kWh from the electricity peak in the afternoon. The electricity storage are able to reduce the peak power with 40 kWh/h, electricity cost with up to 137 SEK and the greenhouse gas emissions with up to 13 kg CO2 depending on season and country.

    The electricity storage is not profitable in an economical point of view today, because of life time of the electricity storage and the electricity price today but mostly on the high investments cost. The cost of reducing the greenhouse gas intensity is between 8-55 SEK/ kg CO2 in average during a year, depending on season and country. The investment cost of electricity storage will be reduced in the future and in 3 years it could be profitable with electricity storage in some countries.

    Further investigations about the impact of greenhouse gas emissions and electricity cost for smart appliances and electrical vehicles have also been done in this thesis.

  • 131.
    Johansson, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energiutvinning i Fumingverket på Rönnskärsverken2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The project was conducted as a thesis in engineering education with a focus on energy. The work was done at New Boliden’s smelters, Rönnskärsverken, in Skellefteå.

    The purpose of this degree of project was to find a more economically optimal process in the fuming plant for zinc- and energy production and improve the interaction between the energy center. Largest producer of steam and district heating at Rönnskär smelter is the fuming plant.

    Different operation modes affect both production of steam and district heating. Availability of zinc rich slag and reduced steam production over tapping of slag has the biggest influence. At low production of steam at the fuming plant and a big need of steam at the rest of Rönnskärs processes together with big consumption of district heating an oil-fire boiler is used to maintain then need of steam. The consumption of oil is a significant cost at Rönnskär smelter.

    During the last years the energy production have decreased dependent of zinc- production. Preliminary calculations show that variations in the fuming plant operations leads to large variations in the steam production.

    A mass- and energy balance for cold crushed slag has been calculated to control how much energy that are cooled down by water before the precipitator. The result shows that 14 MW could be recovered.

    Attempt to lower the oil consumption independent of how the fuming are operated was calculated and experiments were performed. A short-term solution can be reached with the plastic burning and a longer-term with installation of an economizer.

    Pay-off for the economizer is reached by lowering the oil consumption. Data from March 2010 shows an approximate 30 % less oil consumption. A similar result in about nine month per year with an investment cost of 15 million, gives a pay-off in about four years. Additional oil can be saved with continuous plastic combustion which can give up to 60 % less oil consumption. The procedure can be established by investment in an charging bin.

    A short-term solution for steam production, that can be used today, is to mix plastics with the cold crushed slag in order to increase the energy production and lowering the coal consumption. This because of plastics contains coal and hydrogen which also can act as a reducing agent.

    Experiments to check if plastic combustion can be used during slag converting or under tapping of the zinc reduced slag were done. Reduced oil consumption under three batches estimates that about 14 tkr can be saved. Experiment under tapping shows that there are opportunities to stabilize the steam flow which gives fewer start and stop combustions in the oil-fire boiler.

  • 132.
    Johansson, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konsekvenser av ett omfattande elavbrott inom den kommunala äldrevården2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    During the last couple of decades the society has gone through a change where advancement in technology development have meant a transformations from at industrial society to an information society. In today’s society, almost everything contains components which depends on electricity to function. An increasing dependence on electricity makes the society vulnerable and especially the healthcare chain. The Swedish hospitals have capacity to handle longer power breaks, but a subsector which have not been investigated in the same extent is the municipal retirement homes.

     

    This thesis will look into the municipal retirement homes situation during a long and large-scale power outage with critical weather conditions. The thesis will analyze the consequences that might emerge due to a power outage and to what extent there is capacity to manage a situation like this which often mean some sort of emergency power.

     

    The work consisted of calculating the power requirement for a reference building during critical weather conditions. Furthermore, a simulation was done to investigate the time it took for the building to cool down during a cold winter period with the absent of a heating system and also what the indoor temperature would be in the building during a warm summer period with no access to a cooling system. The work was done with the simulation program IDA Indoor Climate and Energy and hand calculations. In addition, the consequences of a power break for retirement homes was analyzed, what capacity there is to handle this and measures that can be implemented.

     

    The result of the work shows that the dependence of electricity is rather large and the consequences of a large-scale power outage can result in big impact on the retirement homes. Important functions in the society might be affected which will make the situation in the retirement homes even worse. The temperature inside the building decreases rapidly without heating systems during a cooled winter period and a hot summer period without a cooling system would mean great stresses on the retirement homes. The ability to manage a large power break varies in the municipality and in some parts there is no resources in the form of emergency power. The result also shows that it requires quite big emergency power generators to meet the power requirement. These generators consume large amount of fuel and it is therefore important to have a well-functioning fuel supply plan.   

  • 133.
    Johansson, André
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av ett uppvärmningssystem vid två sameskolor i Karesuando, Norrbotten2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Specialfastigheter Sweden AB manages two properties in Karesuando, Norrbotten. The properties are used as Sami schools with children from kindergarten to sixth grade. The properties have a heating system that consists of two oil-fired boilers and a number of water heaters that supplies heat in the form of a warm water heating system. These boilers are located in separated buildings, in event of a stop on one single oil-fired boiler, can in the worst scenario only one oil-fired boiler supply both buildings. This is neither sustainable nor an energy -efficient solution.

    An energy- efficient solution to this problem is required to reduce its dependence on oil and the high cost of both transportation and purchasing. The best option that applies to these properties is to convert the current oil-fired boilers to a geothermal heating system when a connection to the district heating or solid fuel boiler is not an option. The purpose of this work is to find alternative energy efficient solutions for replacement of a fossil fuel heating system and reduce the heating costs for two Sami Scholes in Karesuando, Norrbotten.

    By calculating the properties total thermal energy losses in the form of heat, using different heat resistance, thermal transmittance and transmission losses, resulted to a energy loss of 217 500 kWh/year. With this information, the dimensioning of the geothermal heating system six main parts could begin. These parts are dimensioning of the drill hole, heat pump, additional heating, water heater, heat emission system or so called radiators, and at last the electric service line.

    The geothermal heating system is calculated to cover 60-70 % of the property's maximum heat demand, which result to cover approximately 90% of the property’s annual heat demand. The remaining 30-40 % is additional heating.

     An renewed heating system with a geothermal heat pump size of 72 kW and additional heating  at 27 kW, giving an annual reduction of heat costs at 162 000 SEK and an annual profit of 111 000 SEK in comparison with the oil-fired boilers heating system.

  • 134.
    Johansson, Anna
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av ventilationssystem: Boliden Aitik2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Aitik is a Coppermine located in Gällivare, a small community in northern Sweden where the winter season can be very cold, which means that much energy is required for heating. In order to keep the mining industry as energy efficient as possible, continuous improvements are made to the different processes. Ventilation is not the biggest item when it comes to energy efficiency, but there is still potential to save both economically and energy-efficiently.

    In Aitik there are pump stations to pump up water from the mine, these stations are located in the mountain. To get good conditions in the pump station it requires ventilation and some heating. In pump station 420 it is large volumes to be ventilated, which means large amounts of outdoor air to be heated. Heating batteries does the heating of the outdoor air, these batteries are powered by electricity. The ventilation has the function of removing heat from pumping stations and plants located in the pump station, but also removing diesel gases and radon. The exhaust air is forced through a port that is slightly open all year long. Pump station ventilation is in need of energy efficiency, it is also possible to read from previous documentation that it is in need of improvement. To find potential energy efficiency measures, an analysis of the current ventilation is made using the ABB control system 800xA and documentation about the pump station and some minor measurements of radon and exhaust air temperature. The analysis is then compared with the action proposals that include replacing current ventilation into an FTX aggregate and also a minor action proposal that involves temperature reduction. The comparison takes place both from an energy point of view and from an economic point of view. The result shows that a total energy savings of approximately 64 % can be achieved with an FTX aggregate, where the heat exchanger produces an energy saving of 68 % compered to air heating batteries. The economic part of this result demonstrates that this investment is profitable and has a short payback time. Lowering the temperature would generate an energy saving of about 16 % and the relative humidity would increase slightly but still be within acceptable range. The economic result of this measure gives a smaller amount of cost savings. 

  • 135.
    Johansson, Anton
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av köldbärarsystem med avseende på effektivitet och kapacitet2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Massa- och pappersindustrin utgör en stor andel av energianvändningen i den svenska industriella sektorn. Den energiintensiva industrin innebär en stor möjlighet till besparingar genom energieffektiviserande åtgärder. Denna rapport utreder ett köldbärarsystem som förser eltekniska driftrum med kyla samt avfuktar luften på pappersbruket Smurfit Kappa Piteå. På pappersbruket upplever man i dagsläget att deras köldbärarsystem fungerar ineffektivt och får som följd inte ut den projekterade kyleffekten. Syftet med denna utredning är att öka effektiviteten och kapaciteten på köldbärarsystemet. Målet var att ta fram åtgärdsförslag som bidrar till att uppfylla utredningens syfte. Genomförandet av utredningen har behandlats i tre del- system: Distribution av kyla, produktion av kyla samt användning av kyla. Det huvudsakliga tillvägagångssättet har varit analys av loggade data från styr- regler- och övervakningssystemet Larmia. Utöver detta har också driftprov utförts på kylmaskinerna.

    I undersökningen av distributionssystemet visade det sig att återströmning erhålls i köldbä- rarsystemet, vilket gör att redan kyld köldbärare leds in i kylmaskinen KC2. Detta leder till minskad effektivitet. Problemet med återströmning kan minimeras genom att komplettera det befintliga styrsystemet med en stoppsignal som stänger kylmaskiner vid ett lågt kylbehov.

    Undersökningen av kylmaskinerna visade att KC3 och KC4 fungerar suboptimalt. Vid drift av KC3 varierar utgående köldbärartemperatur kraftigt, vilket medför att den löser ut på frysskydd vid låga börvärden. På grund av detta är börvärdet i dagsläget ställt högre än vad som är önskvärt. För att kunna sänka börvärdet och därmed öka KC3’s kapacitet föreslås en flödesökning, så variationerna dämpas genom värmeväxling till en större värmekapacitet. Denna åtgärd kräver att KC3’s cirkulationspump byts. Driftprovet på KC4 visade att expan- sionsventilen i en av köldmediekretsarna hela tiden är fullt öppen. Detta är en indikation på att ett otillräckligt flöde erhålls i förångaren, då expansionsventilens uppgift är att reglera flödet för att hålla konstant överhettning. Det otillräckliga flödet är orsakat av ett för lågt kondensortryck. Detta leder till att förångaren inte nyttjas fullt. Orsaken till detta är en dålig vattensparventil, som reglerar kylmedelflödet till kondensorn. Lösningen på detta är att byta ut ventilen mot en reglerventil, som styrs mot önskat börvärde på kondensortrycket. Utöver detta bubblar det i synglaset i köldmediekrets 2 och rörtemperaturen ut från economisern och kondensorn är höga, vilket tyder på att något är fel. Detta kan bero på bland annat låg köldmediefyllnad, fel på economisern eller på kondensorn. Som åtgärd på detta föreslås att kylmaskinleverantören kontaktas för felsökning.

    Undersökningen av kylanvändarna visade att totalt 39 styrventiler var fullt öppna under he- la sommaren 2016, där 20 av dem styr avfuktningen i eltekniska driftrum. Orsaken till fullt öppna styrventiler till avfuktarna är att det inställda börvärdena på temperatur och relativ fuktighet är för låga. Detta gör att tillräcklig avfuktning är omöjlig vid rådande köldbärartem- peratur. Problemet kan lösas genom att höja börvärdena eller sänka köldbärartemperaturen. Resterande 19 styrventiler är till luftkylare. Anledningen till de fullt öppna styrventilerna kan bero på att köldbärarflödet är för lågt, luftflödet är för lågt eller att mer elektrisk utrustning installerats i driftrummen. Som en första åtgärd föreslås en justering av köldbärarflödet med injusteringsventilerna för att se till att rätt flöde erhålls i köldbärarsystemet.

  • 136.
    Johansson, Erik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Parametric study of a wastewater heat recovery system for buildings2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Global efforts makes buildings successively more energy efficient. This results in that the percentage of the total energy in the building that is lost to the sewage system, in the form of hot water, is increasing. The characteristics of the wastewater originating from the urban water cycle makes it an attractive heat source which is relatively unexploited. Wastewater heat recovery (WWHR) systems is a group of systems designed to reduce a buildings use of external energy sources by recovering the heat out of the wastewater before it is let out into the sewage.        

    The focus of this report is a parametric study performed on a WWHR system that utilises thermal storage tanks for accumulation of wastewater and a heat pump equipped with heat exchangers for the heat recovery. The studied variables are the amount of energy that the system is able to recover out of the wastewater and the seasonal average COP of the heat pump. The change of these two variables were analysed both as an affect of parameters dependent of system design and on consumption patterns of the residents of the building. The results showed that by properly designing the system the recovery degree can be increased by 31.5 percentage points reaching values above 90 % and the seasonal average COP can be increased by 13.5 % reaching values of 5.13. However, these two variables stands in contrast to each other were maximising one will reduce the other and it is proposed that it is important to take both into account when evaluating a WWHR system. It is also shown that the consumption related parameters have a relatively big effect on the system. The change in recovery degree as a result of these non-controllable parameter is 14 percentage points and the seasonal average COP changes with 4.2 %.        

    The system performance as a result of changing the U-value of the heat exchanger connecting the system to the domestic hot water circuit was also analysed. This showed an exponential relation between the U-value and delivered energy from the heat pump. The results showed that an increase of the U-value from 50 W/K to 6000 W/K increased the yearly energy supplied with 37.6 % but an increase from 1000 W/K to 6000 W/K increased the yearly supplied energy with less than 1 %. This result highlights the importance of properly dimensioning the heat exchanger.

  • 137.
    Johansson, Kristina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av vattenkraftverk2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    On behalf of the company One Nordic AB and Staffan Lundström, this report study several energy-saving measures that can be done at hydroelectric power stations. One Nordic AB wanted three areas to be investigated further a: the processes to keep the floodgate free from ice, b: recycling heat from the electric transformer and c: energy-saving solutions for lightning. The report gives both calculating examples on energy consumption and shows how the saving solutions can be applied in reality.

    The result shows that every process that leads to a more energy efficient solution should start with a deeper analysis which takes the budget, needs and demands in considerations along with all the potential risks. Since many variables make it difficult to present a general best solution the report presents a few recommended solutions to all the three investigated areas.

  • 138.
    Johansson, Kristoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Solceller på flerbostadshus2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden has taken upon themselves several goals to reduce their carbon footprint and exchange fossil fuels for renewable energy sources; Solar power will play an important part in fulfilling these goals. Due to declining costs and a technology that is getting more efficient solar power has seen a rampart growth is system installation the last couple of years. However, often economic support schemes are necessary for making a PV-system profitable, especially in Sweden where the sun doesn’t shine as much. Electricity generation with the use of PV-systems on buildings can be unreliable because the sun might not shine when the building needs the electricity, and the opposite is also a problem where the sun is shining, but the building doesn’t need electricity.

    The main purpose of this of this study was to evaluate the possibilities of a PV-system on two large residential buildings located in Sweden, Umeå. The study was conducted by gathering data about the buildings through measurement, pictures and investigation. With the data acquired a total of five different PV-systems was dimensioned to be tested for performance. The software PVGIS was used to analyze the PV-system performance by making use of climate data to simulate the weather conditions in Sweden. Thereafter the PV-systems economical prerequisites were analyzed by calculating LCOE, payback, present value and IRR.

    The results show that there are possibilities to install PV-systems on the buildings, but if larger systems are to be installed it seems like a battery is needed. If two smaller PV-system of total 113 kWp is installed the study suggest that relatively high levels of power self-sufficiency can be achieved. This is believed to be caused by the very constant electricity loads in the buildings. The energy output per kWp of installed power reaches 775 kWh/kWp on the best roof surfaces and is drastically lowered on the worst surfaces. Such energy exchange is considered low. The economical investigation shows that PV-systems that can use a lot of the produced electricity directly in the building instead of selling it to the public powerline has more profitability.

  • 139.
    Johansson, Viktor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektiva byggnader ikallt klimat: En undersökning av energiprestanda förfyra enfamiljshus i Umeåregionen2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis has been carried out in the autumn of 2011, on assignment of the department of Applied Physics and Electronics (TFE) at Umeå University. The thesis is a part of the ongoing project, Energieffektivt byggande i kallt klimat, which is a collaboration between the municipality of Umeå, Umeå university and market participants in the Umeå region. The goal of this work is to create and compile a solid base of measurements to show the energy saving potential in the housing sector and to explore if there is an increased risk of mold, rot or fungus growth in energy efficient houses. The long-term goal is that the result of this project will lead to increased motivation to build energy efficient houses even in these latitudes.

    A compilation of the energy requirement has been made for four single-familyhouses in the Umeå region throughout the year 2011. Temperatures and humidity has continuously been logged in the various layers of the building components and in indoor and outdoor air. Flow rates and temperatures of water in heating systems and to hot tap water have been logged. Electricity consumption has also been continuously collected. In total, between 27 and 40 sensors were installed in each house.

    The energy use has thereby been identified and categorized according to if the use is for heat, hot tap water, household electricity and in terms of total electricity- and energy use. Performance has been investigated for installations with energy saving purposes such as heat exchangers, a 30 m long preheating pipe buried in the ground and a geothermal heat pump.

    The results of the compilations show that the houses, with normal year corrected values, have an energy requirement for heating and hot tap water at between 67 and 81 kWh/m2y. The heat and hot tap water requirement for one of the houses was only half of the requirement in BBR of 130 kWh/m2y for houses with other type of heating source than electrical heating.

    The measurements show that there is no risk of mold or rot anywhere in any of the houses.

    In one of the houses it was showed that a preheating pipe along with a wellfunctioning heat exchanger was enough so no additional pre-heating of the incoming air was necessary, even during the coldest period of the year.

    The geothermal heat pump delivered in average 2.5 times more energy than it consumed. This reduced the amount of purchased energy for heating and hot tap water by about 60 % on a yearly basis.

    Overall, there is nothing in this research that indicates that there are any hinders for constructing energy efficient buildings in cold climates. No increased risk of rot or mold has been detected which has been a common misconception about energyefficient, airtight houses.

    Rather, there is a quite large saving potential both moneywise for the individual and for the environment, in both the short and the long term.

  • 140.
    Jonas, Burman
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Torrefaction of biomass using hot flue gases2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 141.
    Jonsson, Pierre
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av transformatorstationer åt Vattenfall Eldistribution AB2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 142.
    Jonsson, Thim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Miljöcertifiering av befintlig byggnad: Utredning om tillvägagångssätt och tidsåtgång enligt Miljöbyggnad 3.02018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is a bachelor thesis at Umeå University. The purpose of this report is to show the choice of method, approach and timeframe according to the environmental building for existing buildings. \\ \\ Miljöbyggnad is a certification system in which indicators for energy, environment and materials are examined. If the building meets the requirements, it will receive an environmental certification. Miljöbyggnad started already in 2003, when it was called the Miljöklassad byggnad and was a cooperation between the municipality, companies and government for sustainable development in the construction and real estate sector. This was linked to the environmental goals set by the government in 1999. \\ \\The indicators investigated in this work have been linked to energy and the environment. According to the instructions for environmental construction, many of the indicators can be reported by simulated values or measured/calculated values. \\ The results associated with the indicators have been investigated by measurement, calculation and simulation where comparison of methods has been made. \\ \\ The work has resulted in a proposal for ways in which the company, in connection with an energy declaration, can make a rough estimate of whether an environmental construction process can be done. If the building is considered suitable for such certification, the proposal is that collection of necessary information about the building will take place in the first step. It includes everything from drawings of the entire property to inventory of the property's internal loads. Furthermore, the energy and environmental data of the building will be simulated in order to be able to compare against environmental building requirements. This approach is considered to be most appropriate for most properties. \\ There are easier ways to judge some of the indicators, but it also requires a room/officespace to meet certain conditions.

  • 143.
    Jonsson, Tobias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Tilluftstemperaturens och frånluftsflödets påverkan på en pappersmaskins ångtork och värmeåtervinning2015Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
  • 144.
    Karolina, Bengtsdotter
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Interaktioner mellan svavel, klor och kvicksilver vid avfallsförbränning2018Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    For a long time, mercury has been a very popular to use in different kinds of products due to its unique properties. Which has led to a lot of different things containing mercury ends up in waste plants to be incinerated. Mercury are also considered to be one of the most dangerous substances and therefore emissions needs to be kept at minimum. Oxidizing mercury from its form Hg0 to Hg2+ is considered to be extremely important due to the later are easier to remove from the flue gas. The main objective with this thesis was to investigate if mercury would exist more in its elementary form Hg0 than its oxidized state Hg2+ in the flue gas when the ratio between sulfur and chlorine was changed. The former is insoluble in water and therefore difficult to remove from the flue gas with today’s cleaning facility’s. It is also considered one of the more dangerous substances in the world. The project was done in collaboration with Umeå Energi AB. The method that was used to explore this was measuring the mercury content of the flue gas from the waste fired boiler Dåva 1 outside Umeå. The measurement was done with and without extra sulfur added to the fuel in the form of car tires. An additional analysis was done on the ash from the fabricfilter and from the superheater to see if there was something there to give some clarity on why there would be any change in the amount of mercury. The measurement did indeed indicate that sulfur increases the amount of mercury in the flue gas. The main theory to why this has occurred was the increased amount of SO3, which could be found in the flue gas when extra sulphur was added. SO3 is then absorbed by the activated carbon that is added to the flue gas that should have absorbed Hg0 instead. However, this result is not conclusive and further studies needs to be done. Another possible theory to why this has occurred could be that the increase of sulfur could lead to more Na2SO4 in the particle filter. Which could have led to a decrease of NaCl in the filter that could perhaps be a more efficient oxidizing agent of Hg0 than HCl. Another thing that has been revealed is that the cleaning systems that is used today is capable of cleaning mercury from the flue gas even though the added sulfur caused an increase in the amount.

  • 145.
    Kempe, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvärdering och åtgärdsförslag av energianvändning i kontorsbyggnad2015Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Embla 5 is an office building which has done a large improvement. The clients of this building has made an order of WSP and the student Anders Kempe to calculate the use of energy for the building, and after that result proposing further measures which can decrease the energy use of Embla 5.

    The ground for this report is when calculation of the present energy use of the building is stated. To make that information of a number of parameters such as envelope, the heating system and ventilation has been located and set in to the simulation program IDA ICE which calculate the energy use.

    To improve the energy use further this project has been concentrated to change the system of ventilation. Today the ventilation system is of the kind CAV (constant air volume) and the air flow is dimensioned for after recommendations from BBR and Arbetsmiljöverket in the office spaces. Consider that Embla 5  is an office building where the people only staying for 8-10 hours/day so was the ide to see how much energy saving if the air flow is reduced the time people not being in the building. This VAV-system (variable air volume) was set to go with full air flow weekdays 06:00-19:00 when people can be in the local. All the time around that the air flow is been reduced to 20 % of dimensioned flow (solution 1) and 40 % of dimensioned flow (solution 2) with the same kind of time control. By these solutions the rate of energy use is been calculated and been compared to the present energy use.             

    The saving of energy for the two solutions been around the same about 100 000 [kWh/year]. With a energy price of 1 [SEK/kWh] the saving in money being 100 000 [SEK/year].

    Before Embla 5 renovated the heating rate were 400 000 kWh/year and after renovation the heating rate were 300 000 kW/year. The heating rate had reduced thus the building had been four times bigger. The reason of that is the older part of the building had very large transmissions losses and newer part of the building was built with material with low u-value which decreases the transmissions losses. Another reason is that a new FTX-system is placed in the building with a better efficiency than the older FTX-system.         

  • 146.
    Khalanski, Aliaksei
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Livscykelanalys för olika brytartekniker på mellanspänningsnivå2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Gasen svavelhexafluorid, SF6, har använts i världen för olika ändamål sedan 1960-talet på grund av dess framträdande isolerande och ljusbågssläckande egenskaper. Ett av de bredaste användningsområdena för gasen idag är tillverkningen av mellan- och högspänningsställverk, där den används för släckning av ljusbågar och som ett isolationsmedium i vissa komponenter, till exempel i brytare. De unika fysikaliska egenskaperna av SF6 gör elektrisk utrustning innehållande den gasen mer fördelaktig ur utrymmessynpunkt jämfört med andra tekniska lösningar. Svavelhexafluorid är dock en 23 900 gånger starkare växthusgas på ett 100 års perspektiv jämfört med koldioxid och med det omfattas av Kyotoprotokollet. Det faktumet gör att gasen kräver ett särskilt hanteringssätt under hela dess livscykel eftersom allt läckage av SF6 absolut ska undvikas.

    Skellefteå Kraft använder SF6-gas i sina brytare på hög- och mellanspänningsnivå och eftersom bolaget har beslutat om att utvecklas mot att ha en 100 procent hållbar energiproduktion har användningen av SF6-gas fått större uppmärksamhet. På 36 kV spänningsnivå finns det en teknisk lösning av brytare där isolationsmediet utgörs av luft istället för gas. Dock är nackdelen med den lösningen att den generellt kräver mer utrymme, vilket är viktigt i det sammanhanget ity moderna ställverk på den spänningsnivån placeras inomhus för att minska behovet av underhåll. Syftet med denna studie är därför att jämföra miljöpåverkan från dessa två brytartekniker, nämligen ett luftisolerat ställverk och ett ställverk med brytare i gastank. Studien utgörs i form av en livscykelanalys och kommer att fungera som kunskapsunderlag för Skellefteå Kraft vid framtida reinvesteringar i mellanspänningsställverk.

    Eftersom SF6 är en koldioxidekvivalent fokuserade denna studie enbart på miljöpåverkan i form av utsläpp av koldioxidekvivalenter. Programmet för livscykelanalyser Open LCA tillsammans med Excel användes för att utföra beräkningarna. Miljöpåverkan från ett inomhusställverk antas inkludera två bidrag: ställverksfacken och ställverksbyggnader där betong-, container- och träbyggnader dessutom jämfördes med varandra. Resultatet i denna studie presenterar klimatpåverkan från ett ställverksutförande med två inkommande linjer med totalt fem brytare, dock kan den skapade excelfilen beräkna klimatpåverkan för en valfri ställverksuppställning på spänningsnivån 36 kV. I livscykelanalysen har ett flertal grova antaganden gjorts vilket gör den till en väldigt generell studie, dock gjordes det lika antaganden för de båda typerna av brytare vilket gör att resultatet fungerar som en jämförelse och inte de absoluta värdena på koldioxidutsläppen.

    Resultat visade att vid antagandet om gasläckaget om 1 procent vid produktionen, 0,1 procent vid driften och 1 procent vid avvecklingen av "gas"-ställverket (1;0,1;1 procent) är klimatpåverkan för de båda typerna av ställverk lika stor, med undantaget för träbyggnaden, där "gas"-ställverket orsakar ett cirka 16 procent större utsläpp i jämförelse med "luft"-ställverket. Därjämte vid antagandet om ett större läckage, nämligen 3;0,1;5 procent, vilket också ses som mer realistisk, blir klimatpåverkan för ett "gas"-ställverk från 38 till 67 procent större, beroende på byggnad.

    Även om det ställs särskilda krav på hanteringen av SF6 finns det alltid en liten risk att gasen läcker ut i atmosfären i större mängder. Tillverkarna påstår att båda typerna av brytare är underhållsfria under hela sin livslängd. Dock har ett luftisolerat ställverk större möjligheter för funktionstester och underhåll, vilket också minskar risker för haverier. "Gas"-ställverk saknar nästan helt dessa möjligheter. Ur säkerhetssynpunkt anses ett luftisolerat ställverk vara ett bättre alternativ och ur miljösynpunkt anses de två alternativen vara jämbördiga.

  • 147.
    Khwaja, Salik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Weiland, Fredrik
    Pettersson, Esbjorn
    Wiinikka, Henrik
    Wingren, Anders
    Strandberg, Martin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pommer, Linda
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Padban, Nader
    Hinderson, Anna
    Khodayari, Raziyeh
    Carbo, Michiel
    Nordin, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Entrained Flow Gasification of Torrefied Lignocellulosic Biomass2016In: Papers of the 24TH European Biomass Conference: Setting the Course for a Biobased Economy / [ed] Faaij, APC Baxter, D Grassi, A Helm, P, Amsterdam: ETA Florence Renewable Energies , 2016, p. 1138-1142Conference paper (Refereed)
    Abstract [en]

    An extensive evaluation program was carried out within the European SECTOR project to evaluate the feasibility of torrefied and densified biomass in available entrained flow gasifiers. Different entrained flow reactors (both atmospheric and pressurized) in different scales, from lab scale to a 240 MW industrial gasifier were used for evaluation of torrefied materials as feedstock. Total behaviours of the new fuel throughout the whole supply chains and the EFG systems were evaluated and documented, including process behaviours in terms of operation, gas quality, products of incomplete gasification, etc. Results showed a significant improvement in fuel properties in terms of storage, logistics, milling and feeding behaviour by torrefaction and densification. Entrained flow gasification of the torrefied biomass was also shown to be feasible without any major showstoppers, even improving the gasification processes. Production of tars and other products of incomplete gasification were often found significantly reduced during gasification of torrefied material.

  • 148.
    Kjeang, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Goldak, J
    Carleton University, Ottawa, Canada.
    Golriz, Mohammad R
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gu, J
    Carleton University, Ottawa, Canada.
    James, D
    Energy Visions Inc., Calgary, Canada.
    Kordesch, K
    Technical University Graz , Austria.
    Modeling methanol crossover by diffusion and electro-osmosis in a flowing electrolyte direct methanol fuel cell2005In: Fuel Cells, ISSN 1615-6846, E-ISSN 1615-6854, Vol. 5, no 4, p. 486-498Article in journal (Refereed)
    Abstract [en]

    A CFD model is created to analyze methanol transport in a flowing electrolyte direct methanol fuel cell (FE-DMFC) by solving the 3D advection-diffusion equation, with consideration of electro-osmosis. The average methanol flux at the anode and cathode surfaces is simulated and compared to equivalent direct methanol fuel cells. Methanol crossover is defined as methanol flux at the cathode surface, and the results reveal that methanol crossover can be drastically reduced by the flowing electrolyte. The performance of the FE-DMFC at peak power current density is evaluated, and diffusion is shown to be the dominant contribution, although electro-osmosis increases with current density. The power consumption of the electrolyte pump is shown to be negligible compared to the cell power output. This indicates that thin electrolyte channels with high flow rates could further improve the efficiency

  • 149.
    Kjellsson, Anton
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av energi, kostnad och CO2-utsläpp med/utan ångtork och förbränning/sluttäckning med slam rörande slamhantering på ett avloppsreningsverk i Umeå2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    De ökade deponi- och transportkostnaderna har skapat ett ökat intresse att effektivisera hanteringen av avloppsslam. Umeås allmänna avloppsreningsverk (Vakin) tar emot avloppsvatten från mer än 80 000 hushåll och företag och det mesta leds till reningsverket på Ön. Efter 2020 upphör avtalet med Dåva deponi om att avloppsreningsverket får använda slammet till sluttäckning av deponier. Ett alternativ till deponering är torkning med efterföljande förbränning.Detta examensarbete har genomförts på uppdrag av Vakin och syftet var att kartlägga energiflödena och CO2-utsläppen före och efter en implementering av en ångtork i byggnaderna rörande slamhantering. Även effekter av förbränning respektive deponering av slam har inkluderats. Ett mål var presentera ett systemförslag för hur ångtorken kan implementeras till befintlig anläggning. För att uppnå syftet inhämtades data genom inventering på plats och i projektplaneringsverktyget Projectplace. Därefter beräknades och sammanställdes energibehovet, kostnaden och klimatpåverkan för respektive energiförbrukande enhet i Microsoft Excel Förslaget till implementering av ångtorken är baserat på litteraturdata.Resultatet visar att det årliga energibehovet för slamhantering skulle öka från cirka 2 700 MWh till cirka 3 000 MWh. Vilket resulterar i att den årliga kostnaden för slamhantering ökar från cirka 6,2 miljoner kronor till cirka 7,5 miljoner kronor. Men den årliga klimatpåverkan skulle minska från cirka 930 ton CO2 till cirka 490 ton CO2 med en ångtork. Det årliga elbehovet för slamhantering ökar från inget energibehov till 2 100 MWh vid en installation av en ångtork. Detta eftersom cirka hälften av biogasen som tidigare användes till att producera el- och värmeenergi förväntas användas i ångtorken. Detta resulterar i att den årliga elkostnaden minskar från en intäkt på 650 000 kronor till en kostnad på cirka 4,6 miljoner kronor. Vidare ökar den årliga klimatpåverkan för elen från cirka 10 ton CO2 till cirka 180 ton CO2.Det årliga energibehovet för transporten minskar från cirka 2 700 MWh till cirka 900 MWh vid en installation av en ångtork. Eftersom ångtorken reducerar mängden slam som ska transporteras. Vilket resulterar i att den årliga kostnaden för transporten minskar från cirka 4,1 miljoner kronor till cirka 1,4 miljoner kronor. Även klimatpåverkan för transporten minskar från cirka 720 ton CO2 till cirka 240 ton CO2. Det årliga energibehovet idag är oförändrat när Vakin förbränner det torkade slammet. Eftersom energibehovet för sluttäckning inte beaktats och energibehovet för förbränning av torkat slam är noll. Den årliga kostnaden minskar från cirka 2,8 miljoner kronor till cirka 1,6 miljoner kronor. Eftersom mängden slam minskar mer än vad kostnaden för att förbränna slammet ökar. Den årliga klimatpåverkan minskar från cirka 180 ton CO2 till inget CO2-utsläpp. Eftersom klimatpåverkan att förbränna förnybart biologiskt material är noll.

    Energikartläggningen av fastigheterna visar att idag förbrukar utrustningen och belysningen rörande slamhantering cirka 760 MWh respektive 25 MWh el. Byggnaderna rörande slamhantering förbrukar idag cirka 1 200 MWh (byggnad 4) respektive 500 MWh (byggnad 5) värmeenergi. Dessa värden är jämförbara med andra liknande slamhanteringsanläggningar. Ur ett hållbarhetsperspektiv rekommenderas att Vakin installerar en ångtork, vilket medför bland annat en minskad årlig transportsträcka och därav reduceras CO2-utsläppen från transporten. Den mest lämpliga integreringen av en ångtork till ett avloppsreningsverk är att upprätthålla en arbetstemperatur för rötkamrarna med värmen från kondensationen av det förångade vattnet, återcirkulera den överhettade ångan som värms av förbränningen av metangasen från rötkamrarna samt blanda torkat slam med blöt slam för att undvika slammets klibbiga fas.

  • 150. Kramb, Jason
    et al.
    Konttinen, Jukka
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Salo, Kari
    Roberts, Michael
    Elimination of arsenic-containing emissions from gasification of chromated copper arsenate wood2016In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 181, p. 319-324Article in journal (Refereed)
    Abstract [en]

    The behavior of arsenic in chromated copper arsenate containing wood during gasification was modeled using thermodynamic equilibrium calculations. The results of the model were validated using bench-scale gasification tests. It is shown that over 99.6% of arsenic can be removed from the product gas by a hot filter when the gas is cooled below the predicted condensation temperature.

1234567 101 - 150 of 363
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf