Dalarna University's logo and link to the university's website

du.sePublikasjoner
Endre søk
Begrens søket
1234567 1 - 50 of 728
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Abd Alrahman, Chadi
    Högskolan Dalarna, Akademin Industri och samhälle, Elektroteknik.
    Evaluation of a PVT Air Collector2015Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Hybrid Photovoltaic Thermal (PVT) collectors are an emerging technology that

    combines PV and solar thermal systems in a single solar collector producing heat and

    electricity simultaneously. The focus of this thesis work is to evaluate the performance of

    unglazed open loop PVT air system integrated on a garage roof in Borlänge. As it is

    thought to have a significant potential for preheating ventilation of the building and

    improving the PV modules electrical efficiency. The performance evaluation is important

    to optimize the cooling strategy of the collector in order to enhance its electrical efficiency

    and maximize the production of thermal energy. The evaluation process involves

    monitoring the electrical and thermal energies for a certain period of time and investigating

    the cooling effect on the performance through controlling the air mass flow provided by a

    variable speed fan connected to the collector by an air distribution duct. The distribution

    duct transfers the heated outlet air from the collector to inside the building.

    The PVT air collector consists of 34 Solibro CIGS type PV modules (115 Wp for each

    module) which are roof integrated and have replaced the traditional roof material. The

    collector is oriented toward the south-west with a tilt of 29 ᵒ. The collector consists of 17

    parallel air ducts formed between the PV modules and the insulated roof surface. Each air

    duct has a depth of 0.05 m, length of 2.38 m and width of 2.38 m. The air ducts are

    connected to each other through holes. The monitoring system is based on using T-type

    thermocouples to measure the relevant temperatures, air sensor to measure the air mass

    flow. These parameters are needed to calculate the thermal energy. The monitoring system

    contains also voltage dividers to measure the PV modules voltage and shunt resistance to

    measure the PV current, and AC energy meters which are needed to calculate the

    produced electrical energy. All signals recorded from the thermocouples, voltage dividers

    and shunt resistances are connected to data loggers. The strategy of cooling in this work

    was based on switching the fan on, only when the difference between the air duct

    temperature (under the middle of top of PV column) and the room temperature becomes

    higher than 5 °C. This strategy was effective in term of avoiding high electrical

    consumption by the fan, and it is recommended for further development. The temperature

    difference of 5 °C is the minimum value to compensate the heat losses in the collecting

    duct and distribution duct.

    The PVT air collector has an area of (Ac=32 m2), and air mass flow of 0.002 kg/s m2.

    The nominal output power of the collector is 4 kWppv (34 CIGS modules with 115

    Wppvfor each module). The collector produces thermal output energy of 6.88 kWth/day

    (0.21 kWth/m2 day) and an electrical output energy of 13.46 kWhel/day (0.42 kWhel/m2

    day) with cooling case. The PVT air collector has a daily thermal energy yield of 1.72

    kWhth/kWppv, and a daily PV electrical energy yield of 3.36 kWhel /kWppv. The fan energy

    requirement in this case was 0.18 kWh/day which is very small compared to the electrical

    energy generated by the PV collector. The obtained thermal efficiency was 8 % which is

    small compared to the results reported in literature for PVT air collectors. The small

    thermal efficiency was due to small operating air mass flow. Therefore, the study suggests

    increasing the air mass flow by a factor of 25. The electrical efficiency was fluctuating

    around 14 %, which is higher than the theoretical efficiency of the PV modules, and this

    discrepancy was due to the poor method of recording the solar irradiance in the location.

    Due to shading effect, it was better to use more than one pyranometer.

    Fulltekst (pdf)
    fulltext
  • 2.
    Abdelmageed, Rana
    Högskolan Dalarna, Institutionen för information och teknik.
    The implementation of a solar photovoltaic park with potential energy storage on SSAB's industrial area and its impact onthe internal electricity system2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The global push for increased renewable energy in power production is reshaping how industries approach energy systems. As the urgency to combat climate change grows, industries are integrating alternative power pathways alongside existing systems. This shift is driven by factors such as renewable energy adoption, energy storage advances, decentralization, electrification, circular economy principles, regulatory support, sustainability goals, and technological progress. These changes not only yield economic benefits but also enhance environmental and social impact. Integrating alternative pathways necessitates strategic planning, optimization, and a phased approach for seamless integration. Through these transformations, industries position themselves as sustainability leaders, align with climate goals, and ensure long-term energy security.

    The proposed implementation of a photovoltaic (PV) system at SSAB's steel production plant in Borlänge, specifically for forming line 4's electricity needs, will have a positive impact. This integration introduces renewable energy generation, offsetting the load and reducing reliance on the grid during peak hours, potentially leading to lower costs. It aligns with SSAB's environmental goals by curbing emissions, bolsters energy resilience, and aiding peak demand management. However, challenges in grid integration and infrastructure adjustments must be addressed for successful implementation. Overall, this move embodies SSAB's commitment to sustainability and efficient operations. 

    Through the utilization of simulation tools such as PVsyst and Homer Pro, an extensive study was conducted to investigate diverse scenarios involving combinations of a PV system, hydrogen modules, batteries, and a grid-connected load. The primary aim was to assess the feasibility of these scenarios within the energy system context. By leveraging PVsyst's capabilities for photovoltaic system analysis and Homer Pro's system optimization features, the study comprehensively examines interactions between electricity generation, storage, and consumption. This simulation-driven approach provided valuable insights into the performance dynamics, energy balance, and economic viability of each configuration, aiding in the informed selection of optimal combinations that align with the project's feasibility objectives.

    The results obtained suggest that the ideal size for the PV system in this context is 2.7 MW, allowing for an annual energy generation of 2.5 GWh. The electricity output aligns well with the yearly demand of 2.4 GWh for Forming Line 4

    The results from different scenarios offer valuable insights into how integrating renewable energy and incorporating energy storage affect the overall efficiency and cost-effectiveness of the system. Each scenario was assessed in comparison to the base case of grid connection, uncovering a spectrum of LCOE values. It is noteworthy that the highest LCOE, reaching 0.12 €/kWh, was observed when all renewable resources were combined, whereas the lowest LCOE, at 0.059 €/kWh, was achieved with the PV system-only configuration.

    Fulltekst (pdf)
    fulltext
  • 3.
    Abdi, Faisa
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Farah, Muse
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Energieffektivisering av Limatvätten AB: Värmeåtervinning från manglar2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Energieffektivisering är intressant för alla industrier, eftersom det handlar om minskning av både energianvändning och kostnad. Syftet med detta examensarbete är att analysera potentiell energiåtervinning av spillvärme från en mangel vid Limatvätten AB.

    Limatvätten AB är en stor och modern tvätterianläggning. Limatvätten tvättar åt främst hotell- och restaurangkunder. Limatvätten AB har egna textilier som hyrs ut till hotell, konferenser m.m. Största kunderna finns i Sälenfjällen och Siljansregionen.

    Då inga processdata fanns tillgängliga för detta arbete krävdes mätningar för att få basinformationen. Utifrån mätningar beräknas mängden av energi som kan återvinnas.

    Systemförslag för värmeåtervinning ges även i rapporten. Aquavent är en värmeväxlare som använder ventilationsvärme från manglar. Vattnet som värms upp i aquavent leds in i tvättrören, vilket leder till minskning av ångförbrukning i tvättprocesser. Temperaturförändring är beroende av värmeväxlarens verkningsgrad, ju högre temperaturförändring det är desto mer mängd av energiåtervinning fås.

    Efter identifiering av problemet kartlades tidsplan, lämpliga instrument samt intressanta parametrar. Fukthalten, temperaturen och dynamiska trycket har mätts. Formlerna som beskrivs i teoriavsnittet har använts till de flesta beräkningarna med hjälp av Excel.

    Av resultatet framkommer att maximala energibesparingen blir 184 MWh/år om all överskottsvärme från manglarna återanvänds. Utifrån resultatet blir den totala besparingspotentialen på 57 000 SEK/år. Ytterligare kompletterande mätningar och analyser behövs för att få tillräckligt bra beslutsunderlag. Men detta arbete tyder på att ytterligare analys är intressant. Resultaten visar det att finns potential att använda överskottsvärme från Limatvättens manglar. Förutom besparingen av energin så minskas också klimatpåverkan eftersom överskottsenergin återanvänds igen som annars skulle försvinna ut i atmosfären. Om två av manglarna kopplas med ett värmeåtervinningssystem, resulterar det en dubblering på besparingspotentialen.

    För att få ett mera noggrant resultat kunde man logga en längre tid för mätningarna för att se förändring kring de mätande storheterna t.ex. genom att installera mätare som loggar till en dag eller till med en vecka. Övervakning och tolererande givare behövs dock.

    Fulltekst (pdf)
    fulltext
  • 4.
    Abrahamsson, Jonas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lindqvist, Jakob
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Nedsmutsade värmesystems påverkan på energisystemet: Effektivisering vid användning av rengöringsmetoder2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Nedsmutsning av värmesystem är ett icke välkänt problem som kan få stora ekonomiska konsekvenser. På grund av mineraler och lågt pH-värde i systemet uppkommer kalkavlagringar och korrosion som kan täppa igen systemet och kan skada komponenter. Detta kommer resultera i en ökad energianvändning för användare och en högre tillförd energi från fjärrvärmeproducenten. Syftet med arbetet är att studera olika metoder för rengöring av värmesystem och om det är lönsamt med rengöring av värmesystem. Rengöringens effekt på fjärrvärmebehovet och hur det påverkar växthusgasutsläppet och primärenergianvändningen. Samt undersöka om underhåll av värmesystemet ger mindre energianvändning än att bygga om klimatskalet. Tidigare studier inom området undersöktes och relevant data samlades in efter samtal med intressanta företag som arbetar med rengöring av värmesystem. Rengöring av värmesystemen jämfördes med olika åtgärdspaket som ombyggnad av klimatskalet och värmeåtervinning av ventilation. Rengöring av värmesystemet med en effektivisering på 10 % gav ett minskat fjärrvärmebehov på 1,63 GWh per år samt ett minskat utsläpp på 177 ton CO2e per år. Det minskade fjärrvärmebehovet gav en minskad primärenergianvändning med 113 750 kWh per år. Installation av rengöringssystem kan ge Tunabyggen en besparing på 759 200 kr per år för hela Tjärna Ängar. Slutsatsen med arbetet är att rengöring förlänger värmesystems livslängd men kan inte ersätta ombyggnation av klimatskalet när det gäller minskad energianvändning.

  • 5.
    Abrahamsson, Lena
    et al.
    Luleå tekniska universitet, Arbetsvetenskap.
    Enander, Mats
    Olsson, Hans
    Luleå tekniska universitet.
    Ranhagen, Ulf
    Luleå tekniska universitet, Arkitektur och vatten.
    Fallstudierapport: Iggesunds bruk. Efterbehandlingen. Arbetsrapport1993Rapport (Annet vitenskapelig)
  • 6.
    Abrahamsson, Lena
    et al.
    Luleå tekniska universitet, Arbetsvetenskap.
    Enander, Mats
    Luleå tekniska universitet.
    Olsson, Hans
    Luleå tekniska universitet.
    Ranhagen, Ulf
    Luleå tekniska universitet, Arkitektur och vatten.
    Förstudie av massabalshanteringen vid Iggesunds kartongbruk: arbetsrapport1996Rapport (Annet vitenskapelig)
  • 7.
    Abreu Saraiva Freitas, Iuri
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Indoor climate: A comparison of residential units in Tjärna Ängar, Borlänge before and after retrofitting2018Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study try to understand which aspects were fundamental to indoor climate and how to obtain them in order to provide the best possible experience in the thermal comfort of individuals. Thus, arose the studies of Fanger, which was the seed for a new era of discoveries in the area and founded the knowledge our society have today in this globally used standards and norms. Referring to these fundamental aspects of the indoor comfort, data collection was taken in situ to show in details what was happening. This study was executed in order to demonstrate the differences between the data previous and after a process of retrofitting in dwellings built in the 60s and 70s of the century past, in the district of Tjärna Ängar, Borlänge, Sweden. The comparative results using criteria such as Predicted Mean Vote (PMV), Predicted Percentage Dissatisfied (PPD), Draft Rate (DR), air velocity, Mean Radiant Temperature (MRT), Relative Humidity (RH) and air temperature, showed an improvement in 6 of the 8 parameters analyzed. Confirming the expectation that through the retrofitting the residents will be more satisfied, obtain better quality of indoor climate comfort and also increase occupied area in these dwellings.

    Fulltekst (pdf)
    fulltext
  • 8.
    Ahamed, Anees
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Accelerated Aging of First-surface Enhanced Aluminum Solar Reflectors under Damp Heat Conditions2016Independent thesis Advanced level (degree of Master (Two Years)), 25 poäng / 37,5 hpOppgave
    Abstract [en]

    Solar reflectors are one of the main components of concentrating solar power systems. With new products being developed, durability studies become a necessity for assessing the feasibility of commercial application. In this project, accelerated aging of three types of first-surface enhanced aluminum reflectors and one type of second-surface silvered thick glass mirror under damp heat conditions is studied. The project is conducted at the Plataforma Solar de Almería (PSA), in collaboration with German Aerospace Center (DLR), and Center for Energy, Environment and Technology (CIEMAT), Spain.

     

    The study is centered on analyzing the effect of soiling on degradation of reflectors. In addition to conventional methods, space resolved specular reflectometry is utilized for comparative purpose. Damp heat test conditions are simulated in a climatic test chamber. Test is conducted with reference to International Electrotechnical Commission standard IEC 62108 10.7a: damp heat test guidelines. The reflector samples are artificially soiled with natural and synthetic test sands of varying composition. Reflector performance is assessed based on the reduction in monochromatic specular reflectance.

     

    From the tests, a comparative assessment of the candidate reflectors is obtained. Aluminum samples suffered higher degradation than silvered glass mirrors. Aluminum reflectors with polymer top coat permanently retained soil residue. It is observed that presence of chlorides and organic components caused corrosion on all the types of reflectors tested. Surface roughening is the reason for performance deterioration in most of the cases. By comparing different reflectance measurement methods, the significance of total area of the measurement spot in the measurement procedures could be highlighted. It is suggested that for studies involving artificial soiling, the grain size of sand is to be factored in.

  • 9.
    Ahmad Nia, Pardis
    Högskolan Dalarna, Institutionen för information och teknik.
    Shading and natural ventilation, addressing indoor overheating in the present and future through the case study of Bysjöstrand eco-village2021Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Climate change temperatures expected to rise and extreme heat events (HW) canbe intensified. The influence of climate change on the built environment willbecame more apparent over the coming years. For example, there would be ashift in the risk of overheating in buildings, as well as the cooling and heatingneeds.Studies found that design strategies used to optimize buildings for winter like:good thermal insulation, high airtightness, and extra heat gains increase the riskof overheating. Thus, because of climate change, there is a need for checking thebuildings for summer conditions even in heating dominated countries.This study aims to investigate the potential of two main passive design strategiesto mitigate indoor overheating: ventilation and shading. The main focus of thisstudy is on single-family homes within the Swedish context. Bysjöstrand EkobyAssociation’s Bysjöstrand eco-village project is used as case study. 30 singlefamilyhomes are simulated using Honeybee to run EnergyPlus for calculatingindoor mean air temperature values, extracting the number of hour andpercentages of overheating for each building.Six alternative scenarios were used to evaluate the eco-village. The firststructures were assessed to determine the hours and percentage of time spentoverheating in the present and future situations. The second scenarios, whichinvolved utilizing natural ventilation, was tested to determine if and to what extentit can help to reduce the overheating risk in present and future.A combination of natural ventilation and shading was used for the last scenariosboth for current and future climate.According to the findings, natural ventilation has the greatest influence in reducingoverheating. Combining these two strategies in 2020 and 2070 can lower theaverage percentages of overheating from 17.5 % to 0.6 % and 52.8 % to 12.4%,respectively.The majority of the overheating risk may be addressed using passive strategies,based on the results. More detailed building design is likely be able to eliminateoverheating in single family homes, however, as this study showed it is importantto consider passive strategies from the early stage on the design process.

    Fulltekst (pdf)
    fulltext
  • 10.
    Ahmadi Moghadam, Parham
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Steel Sheet Applications and Integrated Heat Management2016Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Increasing energy use has caused many environmental problems including global warming. Energy use is growing rapidly in developing countries and surprisingly a remarkable portion of it is associated with consumed energy to keep the temperature comfortable inside the buildings. Therefore, identifying renewable technologies for cooling and heating is essential. This study introduced applications of steel sheets integrated into the buildings to save energy based on existing technologies. In addition, the proposed application was found to have a considerable chance of market success.

    Also, satisfying energy needs for space heating and cooling in a single room by using one of the selected applications in different Köppen climate classes was investigated to estimate which climates have a proper potential for benefiting from the application. This study included three independent parts and the results related to each part have been used in the next part.

    The first part recognizes six different technologies through literature review including Cool Roof, Solar Chimney, Steel Cladding of Building, Night Radiative Cooling, Elastomer Metal Absorber, and Solar Distillation. The second part evaluated the application of different technologies by gathering the experts’ ideas via performing a Delphi method. The results showed that the Solar Chimney has a proper chance for the market.

    The third part simulated both a solar chimney and a solar chimney with evaporation which were connected to a single well insulated room with a considerable thermal mass. The combination was simulated as a system to estimate the possibility of satisfying cooling needs and heating needs in different climate classes. A Trombe-wall was selected as a sample design for the Solar Chimney and was simulated in different climates. The results implied that the solar chimney had the capability of reducing the cooling needs more than 25% in all of the studied locations and 100% in some locations with dry or temperate climate such as Mashhad, Madrid, and Istanbul. It was also observed that the heating needs were satisfied more than 50% in all of the studied locations, even for the continental climate such as Stockholm and 100% in most locations with a dry climate. Therefore, the Solar Chimney reduces energy use, saves environment resources, and it is a cost effective application. Furthermore, it saves the equipment costs in many locations. All the results mentioned above make the solar chimney a very practical and attractive tool for a wide range of climates.

    Fulltekst (pdf)
    fulltext
  • 11.
    Aishwarya, Veena Aishwarya
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Effects of Soling on the Solar Radiation Sensors for Indian Climatic Conditions2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The satisfaction and elation that accompany the successful completion of any task

    would be incomplete without the mention of the people who have made it possible. It is a great

    privilege to express my gratitude and respect to all those who have guided me and inspired me

    during the period of the project work.

    First and foremost, I express my sincere gratitude to my University professor

    Fiedler Frank, Program Coordinator, Dalarna University, Borlange, Sweden who encouraged

    and permitted me to have my project in the second semester itself.

    I owe a lot to my supervisor Rönnelid Mats, Associate Professor of Energy and

    Environmental Technology, Dalarna University, Borlange, Sweden for his valuable

    suggestions, constructive criticism and encouragement for the project.

    I deem it to be a great privilege in thanking my external supervisor Dr.Richard

    Meyer, Founder and Managing Director (Suntrace GmbH) and Marko Schwandt, Advisor, Solar

    Expert en Suntrace GmbH for giving an opportunity to work under him. Their guidance,

    academic freedom and co-operation have helped me in completing my project.

    My heartfelt thanks to Dr. S. Gomathinayagam, Director General, NIWE and Dr.G.Giridhar,

    Deputy Director General & Head, SRRA department, NIWE for providing me the necessary

    facilities for the completion of my masters project. I am indebted to Dr.Indradip Mitra,Senior

    Technical Advisor at GIZ GmbH and Kaushal Chhatbar, Project Manager, Project

    Development at Suntrace GmbH , for their valuable suggestions and support.

    I also pay my sincere regards to the staffs of SRRA department for their support

    during the period of my project. I owe a lot to my family, who always motivated me and brought

    me to this level. Finally I submit my obeisance to THE ALMIGHTY for constantly supporting

    me and blessing me with the necessary strength to carry out this research.

  • 12.
    Ajayi, Adeyemi Kazeem
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    New Housing Developments: A Localisation Strategy considering Energy-Efficiency from an Urban Structure and Transport Perspective for the city of Falun2020Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    There are several considerations when planning new housing developments,

    and resultant problems require critical analysis. This thesis has focused on

    studying some part of the potential issues in the case of a project in the city of

    Falun.

    The focus has been on energy and greenhouse gases (GHG)-efficient structures,

    through the analysis of the relationship between the transport system and

    residential development that can contribute to the reduction in emission’s harmful

    effect on human health and the environment. The overall aim has been on the

    sustainable location of housing with regards to transport energy, and it included

    the review of densification in the development of city planning as a measure.

    These courses of action, together with other considered measures been

    explored, are to provide solutions which can contribute to the livability, a greener

    environment and lower the levels of GHG, as well as the use of energy from

    transport.

    Densification is a significant concern when planning for future infrastructure and

    developments in a city. It is not just about housing; dense cities use less energy

    and the denser a city, the more sustainable they set to be.

    The significance of the transport system in an urban environment is enormous

    due to the level of its impact as a major user of energy, specifically petroleum

    product consumption. It is essential to note the importance of the effect that GHG

    and energy use from transport has on the health and wellbeing of city inhabitants,

    the society, as well as humans in general. Therefore, it is most important to strive

    to reduce the need for energy use from transport and to lower the levels of

    transport GHG.

    The city of Falun is planning for new housing development, with comprehensive

    plans for future urban development of areas within and around the city. There is

    a current proposal for the densification of central areas; however, they are also

    proposing new large areas on the periphery, which may be counter-productive

    from a transport point of view.

    This circumstance could lead to more car travel within and around the city, which

    leads to increases in carbon dioxide (CO2) emissions and fuel use, and in turn,

    increased in environmental pollution. Thus, the thesis purpose has been to

    investigate the energy use and carbon dioxide emissions in related scenarios.

    The aim is studying the proposed new housing development potentials to reduce

    car travel through an urban strategy measure such as smart growth; therefore,

    the selection of the following research questions below:

    • Will the proposal in the detailed, comprehensive plan lead to transportation that

    is more or less energy-efficient than today? And Is the proposed development in

    line with previous empirical findings in the research literature?

    • Can the amount of car travel be reduced by planning for a different location

    strategy for future residential development in Falun?

    • Can this analysis be made roughly using simple tools that are easy to use for

    urban planners or architects (not only for advanced GIS-engineers and

    researchers)

    iv

    A literature review facilitates reflection on these issues and studies measures for

    strategies which could be a better alternative when exploited in such or similar

    situation for preferable development. Thus, it’s exploitation in the thesis work.

    This research has been carried out by performing an investigation of the new

    housing development proposal, specifically through analyses of the assumed

    additional usage of passenger cars in the ongoing planned area. Possible

    alternatives are, therefore, examined, e.g. in the frame of options such as

    spreading the housing system into more centrally located and connecting areas,

    improving the relationship between the public transport system and new

    residential development so they could work in tandem.

    From the carried-out work, it has possible to be able to identify some disharmony

    in the ongoing development plans as part of the possible future problems, i.e. the

    case of possible unexploited solution for air pollution from transport energy,

    related issues, and so on. An in-depth interview with two of the Falun city office

    staffs and planners also opens-up on the problems of decision-makers and land

    use policy. Also, site visits provide the perspectives of present and potential

    owners who participated in an impromptu interview.

    Meanwhile, the presented results show that the overall total energy usage

    becomes higher per person with the Falun city´s ongoing-planning proposal, but

    lower with the designed alternative planning scenario. The results were derived

    through calculations, using the “Model for calculating energy use and carbon

    dioxide emissions in different scenarios’’ for generating scenarios that take

    modal split into account as seen in the data, calculation and result’s chapter,

    further in the thesis.

    Fulltekst (pdf)
    fulltext
  • 13.
    Alayan, Sophia
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Design of a PV-Diesel Hybrid System with Unreliable Grid Connection in Lebanon2016Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis is a study on integration of photovoltaic generators into an existing diesel-unreliable grid connected system at the Lebanese village of Khiam. The main goal of implementing PV-diesel hybrid system is to reduce diesel consumption and the import of fossil fuel used in electricity power supply. Before designing the system, it is necessary to create a load profile for 120 households and pre-design the size of the PV generator, the capacity of storage system and inverter type/size selection. The load profile data is based on the average of monthly energy consumption gathered from Khiam village households.

    Detailed simulations and financial analysis are performed with HOMER to compare different systems and their viability. The simulations include four different designs starting from the existing system, diesel generator with unreliable grid, followed by PV generator and unreliable grid, PV and diesel generator and ended with the complete hybrid system. Once the Hybrid system is determined a detailed design is done to optimize the lowest cost PV-diesel hybrid system. The final simulated PV-diesel hybrid system is suggested with a PV capacity of 270 kWp, existing diesel capacity with 200 kVA, an inverter output of 115 kW and battery bank nominal capacity is 1872 kWh. The system renewable fraction is 53% and the project life cycle is 25 years. The PV-diesel hybrid system is projected to produce electricity at a cost of 0.12 USD/kWh. This cost is significantly lower than the 0.26 USD/kWh paid to the diesel operator, as well as lower than 0.13 USD/kWh paid to the utility grid.

    In addition, and according to the given information from the owner, an estimated diesel consumption of 104000 ltr/year, the simulation result shows diesel consumption at 40000 ltr/year. The reduced carbon dioxide production by 65%, from 776 to 272 tons per year, provides further justification for the PV installation in a commercial PV-diesel hybrid system.

    Fulltekst (pdf)
    fulltext
  • 14.
    Alfadel, Usama
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Analysing the Peak Shaving Effect and the Increase in SelfConsumption and Self Sufficiencyof Battery Storage When Coupledto a Single Family House2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aims of the study were to investigate the increase in self-consumption and self-sufficiency and the peak shaving effect of batteries when added to a PV system dimensioned to supply the electric demand of a low energy house built in Sweden. The simulated batteries were Li-ion and the study had a 15-minutes temporal resolution. The study took only the technical aspect of batteries into account and disregarded the economic aspect. A data set of measurements from two near-zero-energy houses built by the Research Institute of Sweden (RISE) was used as inputs. The first house provided measured load profile for an automated load and measured PV production from its 3.6 kW

    p system, the second house provided a load profile for a normal human interactive load. The measured PV production from the 3.6 kWp PV system was compared to the PV production from a simulated 3.6 kWp system taken from PVsyst and System Advisor Model (SAM) and by using different weather data profiles for the simulations. The global irradiance values from the used weather profile data were compared to demonstrate the difference in its values and its effect on the simulated PV production. This comparison between the measured PV production and the simulated one was done because most of the PV simulation software does not take measured PV production as input but they simulate their own PV production based on their built-in weather data; including the software used in this study SAM. The first house with the automated load had an annual energy consumption of Ca. 3600 kWh / Year. The second house with its human interactive load had an annual energy consumption of Ca. 6000 kWh / Year. The load profile was taken as a whole and then divided to different types; heat pump, ventilation and remaining load which represents house hold services. The effect of the input load profile types and its temporal resolution was clarified; this effect came in consistency to what was concluded from the literature review. Different simulations were done varying battery sizes, voltage level, coupling method, dispatch algorithm and other parameter. Three different dispatch algorithms were used for the simulations; two are designed for peak shaving and are built-in tools in SAM while the third algorithm is called Target Zero and designed for maximizing self-consumption and self-sufficiency, it was found in a reference so it was executed in MS Excel. Each of the algorithms used was found to affect both the peaks and the self-consumption and self-sufficiency of the system after adding the batteries compared to before, one as a major effect and the other as a byproduct effect. The peak shaving results varied by varying the batteries and the dispatch algorithm used, for the peak shaving algorithms from SAM, a general decrease in peaks value was reached. For the Target Zero algorithm which optimizes on self-consumption and self-sufficiency, a decrease in the number of the peaks was reached. Both decreases happened by increasing battery sizes. For the self-consumption and self-sufficiency effect, an increase happened with its highest value for 7.2 kWh batteries and by using the three different algorithms. The effect of the load type was also demonstrated by comparing the simulations results for the heat pumps from both houses since both heat pumps were found to have the highest effect on the results. The study was concluded by emphasizing the added values of batteries when coupled to a behind-the-meter PV system. The study could have been more precise and added more information to this field if it had a 1 minute temporal resolution simulations, but patching one minute temporal resolution load profile takes a long time. Working with one minute load profile requires one minute weather profile for the PV simulation which is normally only commercial. Also, having a weather station installed at the house to measure the solar irradiance to be used in the simulation instead of using different weather profiles would have added more accuracy to this paper.

  • 15.
    Alhamwi, MHD Mouaz
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Evaluating the Economic Feasibility for utilizing PV Power Optimizers in Large-scale PV Plants for The Cases of Soiling, Mismatching, and Degradation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The solar PV modules are influenced by a variety of loss mechanisms by which the energy yield is affected. A PV system is the sum of individual PV modules which should ideally operate similarly, however, inhomogeneous soiling, mismatching, and degradation, which are the main focus in this study, lead to dissimilarities in PV modules operating behavior and thus, lead to losses which will be assessed intensively in terms of energy yield.

    The dissimilarities in PV modules are referred to the ambient conditions or the PV modules

    characteristics which result in different modules’ maximum power point (MPP) and thus, different currents generated by each PV modules which cause the mismatching. However, the weakest PV module current governs the string current, and the weakest string voltage governs the voltage.

    Power optimizers are electronic devices connected to the PV modules which adjust the voltages of the PV modules in order to obtain the same current as the weakest module and thus, extract

    the modules’ MPP. Hence, the overall performance of the PV plant is enhanced. On the other hand, the power optimizers add additional cost to the plant’s investment cost and thus, the extra energy yield achieved by utilizing the power optimizers must be sufficient to compensate the additional cost of the power optimizers. This is assessed by designing three systems, a reference system with SMA inverters, a system utilizes Tigo power optimizers and SMA inverters, and a system utilizes SolarEdge power optimizers and inverters. The study considers four different locations which are Borlänge, Madrid, Abu Dhabi, and New Delhi.

    An Excel model is created and validated to emulate the inhomogeneous soiling and to evaluate the economic feasibility of the power optimiz

    ers. The model’s inputs are obtained from PVsyst and the precipitation data is obtained from Meteoblue and SMHI database.

    The economic model is based on the relation between Levelized Cost of Electricity (LCOE) which will be used to derive the discount rate. Graphs representing the discounted payback period as a function of the feed-in tariff for different discount rates is created in order to obtain the discounted payback period.

    The amount of extra energy yielded by the Tigo and the SolarEdge systems is dependent on the soiling accumulated on the PV modules. Relative to the reference system, 6.5 % annual energy gain by the systems utilizing the power optimizers in soiling conditions, up to 2.1 % in the degradation conditions, and up to 9.7 % annual energy gain at 10 % mismatching rate. The extra energy yield is dependent on the location, however, the Tigo and the SolarEdge systems have yielded more energy than the reference system in all cases except one case when the mismatch losses is set to zero.

    The precipitation pattern is very influential, and a scare precipitation leads to a reduction in the energy yield, in this case, the Tigo and the SolarEdge systems overall performance is enhanced and the extra energy gain becomes greater.

    The Tigo system yield slightly more energy than the SolarEdge system in most cases,

    however, during the plant’s lifetime, the SolarEdge system could become more efficient than the Tigo system which is referred to the system’s sizing ratio. The degradation of the system or the soiling accumulation decreases the irradiation and thus, a slightly oversized PV array become suitable and deliver an optimal power to the inverters.

    The SolarEdge system is feasible in all scenarios in terms of LCOE and discounted payback period, although its slightly lower performance relative to the Tigo system, this is referred to its low initial cost in comparison to the other systems. The Tigo system is mostly infeasible although it yields more energy than the reference and the SolarEdge systems, this is referred

    iii

    to its relatively high initial cost. However, feed-

    in tariffs higher than 20 € cent / kWh make

    all systems payback within less than 10 years.

    The results have overall uncertainty within ± 6.5 % including PVsyst, Excel model, and the

    precipitation uncertainties. The uncertainty in the degradation and the mismatching

    calculations is limited to PVsyst uncertainty which is ± 5 %. The uncertainties in LCOE in

    the location of New Delhi, since it is the worst-case scenario, are 5.1 % and 4 % for the

    reference and the systems utilizing power optimizers, respectively.

    Consequently, accommodating the uncertainties to the benefits gained by utilizing power

    optimizers indicates that the energy gain would oscillate in the range of 6 % - 6.9 % for the

    soiling calculations, 2 % - 2.2 % for the degradation simulations, and 9.2 % - 10.2 % for the

    mismatching simulations at 10 % mismatchrate.

    Fulltekst (pdf)
    fulltext
  • 16.
    Al-Hashimi, Mazin
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Modelling Installation Cost for Rooftop PV Systems2015Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The cost of installation of photovoltaic (PV) systems is a substantial fraction of the total cost of the project and the same is increasing with reducing cost of PV modules. This study essentially deals with the cost of installation of rooftop PV systems and presents a cost model for it, based on data collected for more than 700 projects of different capacities, roof types, circumstances, and locations in Sweden. The presented cost model shall give reasonably accurate estimations about the costs associated with the main elements of the process of rooftop PV systems installation, such as labour, shipping, equipment, travel, and accommodation, for different situations as a function of few important variables such as system capacity, roof type, distance to the installation location, etc. The weighted share of cost of the different elements of the cost model out of the total cost of installation was determined. Several relationships between different elements and variables were examined to find relationships that can help to better understand the process of installation and to develop the cost model. The variations in time required per unit system capacity have been examined for several processes of rooftop PV systems installation, to investigate about potential for reduction in the time and thus the cost due to economies of scale.

  • 17.
    Ali, Marwan
    et al.
    Högskolan Dalarna, Institutionen för information och teknik.
    Narani, Eema Sheykhi
    Högskolan Dalarna, Institutionen för information och teknik.
    Optimizing the Performance and Efficiency of District Heating Substations: A Study of the Cooling Process and Overall System Improvements in Ludvika2023Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The concept of future sustainability is driving efforts toward the efficient improvement of energy systems. District heating systems play a key role in balancing the energy system by improving performance and flexibility. As system efficiency increases, fuel consumption decreases, resulting in reduced greenhouse gas emissions and mitigating potential climate impacts, especially when using fossil fuels. In Sweden, district heating has shown significant growth, with a 75 % increase in total heat production over the last 30 years. Furthermore, carbon dioxide emissions have been reduced by approximately 50 % for each delivered kWh in the past 20 years, while renewable energy sources have doubled in the district heating sector. This thesis focuses on optimizing the cooling process to achieve lower return temperatures and higher system efficiency. It also emphasizes the importance of implementing an efficient heat consumption strategy to reduce peak loads and improve overall system efficiency. This approach involves managing demand to minimize peak heat requirements and distribute the load evenly throughout the day, leading to a more resource-effective and efficient system. The case study examines district heating supplied by VB Energy to Ludvikahem AB buildings, using data from Dec 2022 to Jan 2023. Quantitative data from district heating substations and the district heating plant are collected and analyzed to generate qualitative insights. The study proposes theoretical optimization measures based on the findings. The evaluation of substation performance reveals 20 poorly performing substations with various issues. Eight of these substations have technical problems related to substation components, while another eight experience management issues not aligned with specific activity profiles. The load shifting simulation demonstrates a 3% reduction in heat rate peak levels, resulting in approximately 7 kW of subscribed heat rate savings. Energy usage savings reach approximately 0.9%, leading to an increase in energy usage effectiveness. The cost savings amounted to about 3000 SEK over two months for a single building. This research emphasizes the importance of routine control, inspection, and documentation of substation performance to ensure optimal efficiency. Furthermore, indicates that the poorly performing substations that contribute to inefficiencies in the district heating network. Additionally, real-time regulation and load-shifting strategies are vital for optimizing customer consumption and maintaining an efficient district heating system, benefiting both suppliers and consumers.

    Fulltekst (pdf)
    fulltext
  • 18.
    Alkhado, Luqman
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Boussaa, Youcef
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Heat transfer tests on EPS material and massive timber wall component2018Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Timber walls are known to be an energy efficient component in the building envelope.

    These building elements are essential in the passive design and have been pointed out to

    their ability to regulate the indoor climate and reduce energy demand. Heat transfer

    measurements of thermal transmittance value of Iso-timber wall component have been

    performed with the climate chamber at three temperature differences. The influence of

    temperature variations on the thermal conduction of the wall were investigated. The

    temperature on the warm side was kept at room temperature 20 °C while the cold side

    temperature was decreased from 0 C to -20 C during the tests. As the temperature

    difference is increased, the thermal transmittance value of the timber wall component

    decreased slightly due to decrease in the thermal conductivity value. The effect of density

    and porosity on the thermal conductivity may be related to the presence of air voids and

    cell boundaries inside the timber wall. Results have showed that the U-value of the timber

    wall component decreases at higher temperature differences which indicates the higher

    degree of insulation of the timber wall component.

    Fulltekst (pdf)
    fulltext
  • 19.
    Alkhuder, Juma
    et al.
    Högskolan Dalarna, Institutionen för information och teknik.
    Alnabhani, Mazen
    Högskolan Dalarna, Institutionen för information och teknik.
    A comparative study of the materials of Villa Zero project using LCA2021Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    In this thesis a future-world case was undertaken of the life cycle assessment (from cradleto grave) of a single-family house. The house is expected to be constructed by the end of2021 in Borlänge, a city located in Dalarna County. The aim of this study is to investigatewhether the building materials in external walls and roof surpass in terms ofenvironmental impacts compared with other building materials suggested by the authorsof this thesis.Six scenarios were evaluated in terms of the environmental impacts for two buildingelements, external wall, and roof. A base case scenario is taken into consideration foreach building element, considering the fact, that the thermal performance characteristicsof the building materials are comprehensively provided. Consequently, four scenarios aredetermined by the authors.One Click LCA program was used to calculate the environmental impacts of thebuilding materials through the lifecycle of the house during a time horizon of 50 years.Hemp fiber insulation material is planned to be used in the external walls; thus, it isconsidered the baseline case for this thesis. The first study is corresponded to the externalwalls, and it was found that glass wool insulation is more environmentally friendly thanhemp fiber and rock wool insulation.Wood material is planned to be used in the roof; thus, it is considered the baseline casefor this thesis. The second study is corresponded to the roof, and it was found that woodmaterial is more environmentally friendly than concrete and steel.Therefore, the suggested material by the authors surpasses the baseline case materialenvironmentally in respect of external walls, but this was not the case regarding the roof.

    Fulltekst (pdf)
    fulltext
  • 20.
    Alkhuder, Juma
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Johansson, Sandra
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Prestandaanalys vid rengöring av värmeväxlare i fjärrvärmecentral för småhus: Fallstudie på rengöring av en värmeväxlare för småhus2020Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Försmutsning av plattvärmeväxlare i fjärrvärmecentraler minskar avkylningen av det cirkulerande vattnet i fjärrvärmenätet. Detta ökar behovet av värmeproduktion i fjärrvärmeverket vilket medför ökade utsläpp av växthusgaser. Mängden försmutsning beror på vattnets kvalitet och material i systemet. I denna studie undersöks prestandaförändring av värmeväxlare i fjärrvärmecentraler för småhus före och efter rengöring samt för en ny värmeväxlare. Prestandan mäts i laboratorium genom att mäta temperaturer på in- och utlopp på värmeväxlaren vid bestämda flöden. Utvärderingen inkluderar prestandaförändring för UA-värdet, Temperaturverkningsgrad, Effektivitet NTU och möjlig påverkan på växthusgasutsläpp från Borlänge Energis fjärrvärmesystem. En osäkerhetsanalys genomfördes för att bestämma de teoretiska osäkerheterna.Resultaten från studien visar att rengöring av småhusvärmeväxlare med CIP-metoden har en viss effekt på både tappvattenvärmeväxlaren och värmeväxlaren. För värmeväxlaren är förändringen liten där ökningen på UA-värdet ligger mellan 10–202 W/˚C jämfört med tappvattenvärmeväxlaren där det ligger mellan 205–870 W/˚C. Störst effekt har rengöringen på tappvattenvärmeväxlaren vid högre flöde. Värmeöverföringen är likvärdig för en ny värmeväxlare och den rengjorda.En sänkt returtemperatur från fjärrvärmecentraler leder till en förbättrad verkningsgrad på fjärrvärmeverket som bidrar till en minskning av mängden växthusgasutsläpp. Enligt de resultat och beräkningar utförda i studien kan genom rengöring returtemperaturen minskas med 2,3 ˚C ±0,4 % från fjärrvärmecentralerna i småhus till Borlänge Energis fjärrvärmenät.Rengöring av tappvattenvärmeväxlare kan vara ett alternativ till att byta ut mot en ny för småhusägaren, med förutsättning att priset för rengöring är lägre än att köpa en ny och att fjärrvärmesystemet har flödesavgift. Detta gäller dock inte värmeväxlaren för värme där skillnaden i värmeöverföring mellan en smutsig och ny eller rengjord är marginell.

    Fulltekst (pdf)
    fulltext
  • 21.
    Almsalati, Hussam
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Life cycle assessment of villas made by Fiskarhedenvillan, comparison between wood and brick facade2018Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Awareness of climate change has resulted in enormous challenges for developed and

    developing countries. The frightening truth about our environmental situation has led to

    investigations of the causes of these changes and to obstruct these sources gradually but

    quickly. The alarming increase of average temperature of the earth has caused much worry

    around the world. Gas emissions in the atmosphere greatly affect the environment, where

    CO

    2 emissions is one of the most serious factors contributing to the global warming

    potential. As the building sector emits 40% of global energy use and one-third of global

    greenhouse gas emissions, engineers must be educated to choose the best materials that

    lead to reducing CO

    2 emissions. This means selecting materials that have less negative

    impact on the environment and are more “environmentally friendly”.

    This study shows how much CO

    2e emissions are released into the atmosphere from a

    wooden structure villa that consists of two stories, a storage and a garage, with a total area

    of 229.6m2. The results of this case will be compared to a second case, where the external

    wooden siding is replaced with brick veneer. This result of this comparison provides us

    with a guideline in for how the selected materials impact the environment, illuminating the

    importance in choosing the right materials according to their CO

    2e emission levels. In this

    way, the building sector can actively work to reduce the environmental impact.

    To achieve these goals, this study performed via life cycle assessment LCA methodology

    by using the One-Click LCA program. LCA is identified as a technique to assess the

    environmental impact and resources used through a product’s life cycle. This study utilized

    the LCA methodology (cradle to grave), which means starting from the extraction of raw

    materials, to product production, manufacturing, product usage and its end of life. The

    study lifespan was estimated to be 50 years.

    The results of the study verify that the wooden villa is more environmentally friendly than

    the villa made of brick, where carbon dioxide equivalent emission can be reduced to more

    than half by utilizing wood. Implementing the life cycle assessment study to any building

    aids in making the decision to choose the right materials for building according to CO

    2e

    emission. And in this way, the environmental impact caused by the building sector will be

    greatly reduced.

    Fulltekst (pdf)
    fulltext
  • 22.
    Al-Samahiji, Alexander
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Incorporating Solar Energy Into an Aluminium Smelter’s Energy Mix: A study using Aluminium Bahrain2017Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis was aimed at studying the possibility of integrating solar energy in to an existing aluminium smelter in the Kingdom of Bahrain owned by Aluminium Bahrain (ALBA). The smelter was powered by its own in-house natural gas fed power plants. ALBA was chosen as the subject of the study for of two reasons. Firstly, the power station at ALBA was similar in technology to those powering the national grid. Secondly, the nominal power of ALBA was not dissimilar to that of the national grid. This meant that the techniques and technologies investigated were useful in the context of the national grid as well. A literature review was initially conducted to better understand how the current aluminium smelters work, what the possibilities were for introducing solar energy and what has been done previously. The study used publically available information to deduce the energy consumption of the ALBA smelter on an annual basis. For the year 2011 this was found to be in the order of 15.2TWh when ALBA had 2,249MW of nominal plant capacity installed and had consumed about 132MMBCF of natural gas. With the planned pot-line 6 expansion an additional 1,792MW capacity would be added with the corresponding additional gas use and increased energy output. The completion of pot-line 6, scheduled for Q1 2019, would also make ALBA the world’s largest single-site aluminium smelter.  This energy demand information was then used with PVSyst and System Advisor Model simulation software. The aim was to determine what photovoltaic (PV) and concentrated solar power (CSP) energy plants capable of meeting ALBA’s needs would be in terms of power, energy outputs and land usage. Although powering a modern aluminium smelter is possible with today’s solar technology, the area of land required would be very large. It was deduced that using PV fixed tilt arrays, a PV plant of 9.2GWp would be required to deliver the annual energy requirements of ALBA covering a theoretical land area of some 200km2. Utilising CSP plants of central tower and concentric heliostat design would need about 358km2 whereas parabolic trough collector technology would need about 240km2. However a CSP plant utilising linear Fresnel collectors would need about 105km2 of land area. These contiguous land areas are not available in the Kingdom of Bahrain and so alternatives would have to be studied for locating such plants. Another issue would be to find a robust and reliable storage technology to power the plant during the evenings and other times of low solar resource.  It was found that the existing roof areas of ALBA’s pot-lines and cast house would be sufficient to house a PV plant of 6.5MWp utilising standard 250Wp PV modules. This would be larger than the largest plant currently installed in the country which stands at 5MWp developed by Bapco. The plant would produce some 9.7GWh of energy per average year and could be utilised by ALBA. Alternatively, the PV plant could be connected directly to the national grid and thus provide another source of income to ALBA whilst helping in the national drive for harnessing renewable energy. It should be noted that there are more suitable roof areas available at ALBA meaning that the PV plant size could be larger and if more powerful modules are used, the nominal plant capacity would also be increased delivering more annual energy. Due mainly to time constraints, it was not possible to investigate some areas that were highlighted during the course of the study. These included plant costs, energy storage options, modelling and simulating CSP derived heat injection into gas power turbines, water usage requirements and mitigation techniques and the technologies for maintaining the collectors clean and reflective in the harsh desert climate of the country. These are all areas for further work.

  • 23.
    Alsulaiman, Mohamad
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Mohammadi, Najmeh
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Optimal Pitch Distance and Tilt Angleof PV Power Plant for Different Climate2020Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Finding the optimum inter-row spacing and installation tilt for tilted or ground mounted PV systems is a big issue in designing the large-scale PV systems. Increasing the array spacing leads to higher annual generated energy because of the reduced impact of row-shading, but on the other hand, it increases costs of land purchase/lease and wiring costs. Many compromises between performance and cost should be done to design an optimum large-scaled solar plant. One of the criteria in designing of solar power plants is reducing of LCOE, which reflects the cost of every unit of generated energy. Site locations have large impacts on the optimal design of pitch distance and title angles, but such impacts have not been studied extensively in the existing studies, so it is going to bridge this research gap in this thesis.

     

    The main purpose of this research is to investigate the impact of climate conditions on the pitch distance and tilt angle for large-scale PV plant and finding the optimal pitch distance and tilt according to the least cost of production. The impact of climate and meteorological data on the self-shading loss and yield of energy are investigated through a simulation tool, which is PVsyst software here, in different tilt angles and distances between rows. The different climates can be considered by choosing site locations in different latitudes to cover all climate zones. Six cities in temperate climate, three cities in tropic climate and one city in polar climate have been selected. LCOE minimizing is a measure in finding the optimum tilt and pitch distance for a 1 MW solar system installed in different latitudes. In this study the type, size and cost of components have been assumed constant in different climate conditions. There is a wide range of variability in some economic indicators like interest rate and discount rate as well as the cost of land in different climates or even countries in the same climate; then to highlight the impacts of climate conditions on the optimal tilt and pitch distance, these parameters were assumed to be constant in this study.

     

    The results show the optimal tilt of angles increases with getting far of equator in a range between 0° and 40° to capture more direct sunlight, and the optimal raw spacing grows in further locations to equator in a range between 4 m to 11 m to reduce self- shading loss. Moreover, the best module configuration for PV arrays (portrait or landscape) can be different in different climates.

    Fulltekst (pdf)
    fulltext
  • 24.
    Alzén, Axel
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Effektivisering av en produktionsprocess: Analys och förbättringsförslag till en verkstadsindustri2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Isakssons AB tillverkar specialdesignade produkter och effektiva lösningar inom rostfritt, byggplåt och miljöteknik. För tillfället befinner sig företaget i en expansionsfas, vilket ställer större krav på företagets produktion. För att klara av utvecklingen som Isakssons genomgår så har de valt att utföra en ombyggnation av sina lokaler, och dessa måste anpassas för produktionen för att möjliggöra vidare expansion av verksamheten.  Syftet med denna studie är att ge förbättringsförslag till en effektivare produktionsprocess hos ett tillverkande företag med varierande produkter. För att skapa förståelse för produktionsprocessen har flödesscheman, processkartläggningar och tidsstudier utförts. Genom utförandet av en nulägesanalys har förbättringsmöjligheter identifierats, och förändringar har föreslagits utifrån dessa.  Resultatet av frekvensstudierna visar att operatörerna lägger mycket tid på arbete som inte är direkt relaterat till tillverkning av produkter, dvs icke värdeskapande aktiviteter. Genom att skapa flera arbetsstationer för tillverkning samt införa visuella hjälpmedel på arbetsplatsen så kan dessa aktiviteter minskas. Dessutom har förflyttningar av flera av verkstadens maskiner och lager utförts, för att skapa ett enklare flöde genom lokalen.

  • 25.
    Aminmoayed, Katayoon
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Heat recycling case study in commercial building with kitchen ventilation2020Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    In recent decades, the amount of food and fat odor from the commercial kitchenware increasing because of the developing increase rate in the number of restaurants, and concurrently resulting in significant amounts of energy loss from these commercial kitchens. Hence, it is essential to initiate the thinking of an efficient ventilation system in a commercial kitchen perspective, with the feasible solution of heat recovery, whereby the vast amount of heat in commercial kitchens could be secured or re-used with efficient technology.

    The biggest issue relative to commercial kitchens is the amount of heat energy loss used during cooking. To overcome this problem, the installation of suitable devices can contribute to reducing energy demand. Also, issues related to grease and odor that comes out from the kitchens’ exhaust duct needs resolving. With the consideration that there are possibilities of reducing the heating or cooling demands, based on different available technologies utilized in heating, ventilation, and air conditioning (HVAC) systems. This study explores the problem briefly and clarifies each situation with solutions in detail.

    The studied project is a shopping center which is located in the center of Stockholm and named Ringen. It is a three-floor shopping center with two levels of parking lots. In 2016, there was an upgrade by adding the food court (Matteatern) in the center of the ground floor. The main purpose of the project upgrade was the increasing number of visitors to this shopping center, for them to get entertained with refreshments and have nice different kinds of foods in a cozy place. This master thesis, a study on the efficiency of the ventilation system in the food-court, has been undertaken, by considering the project’s energy consumption. The kitchens’ ventilation duct ventilates air from the kitchens to the garage in the underground (-1) floor, whereas the outlet air comes in for usage in the kitchen and garage. Since there is a prohibition against having the ventilation duct on the façade or attached to the roof, the outlet air quality in the garage is, therefore, required to be cleaned from fat and food odor. The current plan works with battery heat recovery ventilation to re-heated up the outlet air and use it in the kitchen. However, ozone injection and polishing filters are two cleaner technologies in use for the prevention of odor and smell.

    The purpose of this study is to investigate if there are significant energy saving system for the undertaken project with an adjustment technology, as well as an assumption of cases by adding heat recovery and air purification to the ventilation system. The importance of energy has set the tone for finding the best solution to avoid unnecessary loss of energy demand from the ventilation of the kitchen in the case study. Besides, it is crucial to find the proper system with the view of energy and cost; meaning that expansive the system should have high quality in energy savings, and with a prospect that it could also save money for the project. If the system is efficient in energy consumption and could save a vast amount of energy loss, in-turn it could as well be used in subsidizing a substantial cost for the project. An ideal solution could be the system with less amount of energy usage, or even if, with a particular gap in energy usage, could be recouped by a vast amount of energy savings.

    The thesis also investigates, through studies on two more optional alternatives to have a comparison of energy consumption and find a good solution for the kitchens’ ventilation, as well as see the amount of efficiency of each system. In the alternatives, one considers separated ventilation for garage and kitchen. The garage’s airflow rate calculated and there is a rotary heat exchanger in the garage ventilation. While as the current plan there is a battery heat exchanger via constant airflow rate in the kitchen. Ozone injection in hence of fat and odor in considering in kitchens ventilation. The second alternative, however, sees the project in a case where there is no ozone injection nor polishing filter and separated ventilation in the garage and kitchen. Also, the kitchens’ ventilation comes up to the roof directly.

    This master thesis project, therefore, presents an energy consumption comparison in different alternatives. It has a view on the current situation, even though there is kitchen outlet air in the garage with a battery heat recovery system and added a polishing filter to optimize the smell from fat. In the case- study comparison, there is separated ventilation and duct for the garage. Also, the rotary heat exchanger in the garage has been considered via the special airflow rate for the garage. it has been taken when there is ozone filtering in the ventilation in place. However, instead of the polishing filters, a rotary heat exchanger has been designed with two different airflow rates. In one other case, there is an estimated airflow rate as the garage air flow rate, and in the kitchen, there is another one. There is no ozone, nor polishing filter in the ventilation system while there is outlet ventilation from the kitchen directly to the roof.

    The current alternative project provides a solution when the outdoor air is heated up by battery in the heat recovery system, then transferred it to the shops and garage. There is ozone injection technology in the commercial hood to break the large parts of fat from the kitchen. Also, there is a polishing filter in the garage to reduce the food and fat odor, and in-turn provides clean air in the parking lots as the outlet air has been for usage in the parking where there is car-wash, and also in shopping floor.

    Meanwhile, calculations from the study demonstrate energy demand and cost- efficiency. The calculations are based on some available data and some assumptions according to real figures. The different temperatures in outdoor and indoor air, the set temperature, and hourly Stockholm datasheet temperature are the base material been used to evaluate heat energy usage. The pressure drop and fan power are parameters been used to calculate the amount of electricity the project. Thus, according to the result, which provides a solution to investigate efficient technology for ventilation systems in commercial kitchens. The major focus of the study stands in a system which has ozone technology and polishing filter in the heat recovery of the commercial kitchen’s ventilation systems, and together in comparison with other cases when there is not.

    Given the result, it has proven that the current alternative in the project has the acceptable amount of energy demand while first consideration alternative(alternative 1) via a rotary heat exchanger in the garage and separated ventilation and airflow rate for kitchen and garage has the best result in energy demand and saving. In contrast, the second alternative with separated rotary ventilation for the garage is neither without ozone nor polishing filter for the cleaning and kitchens ventilation up to the roof has the highest level of energy demand. Hence, with the cost of efficiency, the first alternative meets the lowest amount of cost while the second alternative, which has the highest amount of energy demand has the highest cost. There are also more advantages like an extended lifespan of the air handling unit, lower duct cleaning cost.

    Additionally, the result proves that the first comparison plan has the lowest energy demand, whereas the second alternative has the highest one. With the high amount of energy demand, the energy cost will be increased. Thus, the second alternative has the biggest amount of energy cost, and it's not working. Moreover, there are some other positive points in the current plan, such as the extended lifespan of the air handling unit because of ozone injection in the path and being cleaned. Also, it causes a lower cost for duct cleaning costs as well. The mentioned options can be affected by the result and conclusion. It’s because they are important parameters which can be seen in projects result.

  • 26.
    An, Anastasiia
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Early Design Stage Energy Optimization of Bysjöstrand Ecovillage, Sweden2020Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Decisions made at the early stage of building and settlement design can greatly influence the energy performance of the built environment. However, the type of feasible design intervention and their impact strong depends on project: if it is a new development or a re-development, whether the setting of the project is urban or rural, etc.

    Utilizing Bysjöstrand EcoVillage as a case, the aim of this thesis is to improve the energy performance of a new development at its early design stage through the passive and active use of solar energy.

    The study evaluated the energy saving potential of various passive solar design strategies as well as the solar energy potential of the new development. The steps taken to reduce the energy consumption are focused on the annual heating demand of buildings, since it accounts for more than a half of the total energy consumed by the village. The energy saving potential of the following passive solar design approaches were considered: building siting, building orientation, windows-to-wall ratio (WWR) analysis and insulation thickness optimization from the economic perspective. Furthermore, an assessment of energy generation potential from on-site photovoltaic (PV) systems was conducted. The financial viability of each building’s PV system was also conducted.

    According to the results, the evaluated passive solar design strategies can reduce the annual heating energy consumption close to 17 %. Regarding onsite energy generation, electricity from roof-installed PV systems can cover over 100% of the annual energy consumption estimated for the residential lighting and equipment within the eco-village. In summary, this study has demonstrated that with the above design considerations a 50 % reduction of energy consumption from the utility grid is possible. This study is useful for architects, energy engineers, and other parties who are involved in residential buildings energy performance optimization.

    Fulltekst (pdf)
    fulltext
  • 27.
    An, Anastasiia
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Early Design Stage Energy Optimization of Bysjöstrand Ecovillage, Sweden.2020Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Decisions made at the early stage of building and settlement design can greatly influence the energy performance of the built environment. However, the type of feasible design intervention and their impact strong depends on project: if it is a new development or a re-development, whether the setting of the project is urban or rural, etc. Utilizing Bysjöstrand EcoVillage as a case, the aim of this thesis is to improve the energy performance of a new development at its early design stage through the passive and active use of solar energy. The study evaluated the energy saving potential of various passive solar design strategies as well as the solar energy potential of the new development. The steps taken to reduce the energy consumption are focused on the annual heating demand of buildings, since it accounts for more than a half of the total energy consumed by the village. The energy saving potential of the following passive solar design approaches were considered: building siting, building orientation, windows-to-wall ratio (WWR) analysis and insulation thickness optimization from the economic perspective. Furthermore, an assessment of energy generation potential from on-site photovoltaic (PV) systems was conducted. The financial viability of each building’s PV system was also conducted. According to the results, the evaluated passive solar design strategies can reduce the annual heating energy consumption close to 17 %. Regarding onsite energy generation, electricity from roof-installed PV systems can cover over 100% of the annual energy consumption estimated for the residential lighting and equipment within the eco-village. In summary, this study has demonstrated that with the above design considerations a 50 % reduction of energy consumption from the utility grid is possible. This study is useful for architects, energy engineers, and other parties who are involved in residential buildings energy performance optimization.

    Fulltekst (pdf)
    fulltext
  • 28.
    Andersdotter, Julia
    Högskolan Dalarna, Institutionen för information och teknik.
    Improvement of an electrical coupler cover2022Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study was made for Dellner Couplers and is regarding a development of their electrical coupler cover (ECC).

    The electrical coupler includes several electrical contacts where the current flows, which lets electrical signals to be transported between all carriages in a train when the electrical couplers are connected to each other. An electrical coupler that is not connected to another one will have an ECC that automatically folds down in in front of the coupler to protect the electrical contacts from dust, water, and damage. The current ECC Dellner Couplers have today is made from an extruded aluminium profile, which has desirable properties in all aspects, except that it’s conductive.

    If the ECC encounter the electrical contacts, which can happen during a collision between the train and an animal, the contact between them could cause short circuit since the electricity is always running and can’t be turned off. The development of the ECC is aimed to remove the occurrence of short circuit in case of collision with an animal, but still fulfil the mechanical requirements.

    The method used to find a solution was based around well know concept development methods involving problem identification, identifying customer needs to create a target specification on what the ECC must fulfil, search for external and internal ideas for solving similar problems, performing concept screening on several concept ideas, and implement a finite element analysis (FEA) on the final concepts to see which one has the best potential for success. A part of the focus in the method has also been around material exchange by searching for potential materials in a material database.

    The results imply that adding thickness to the extruded aluminium profile could be a promising concept, which was discovered in the concept screening and FEA. The FEA of the concept shows lower displacement of the ECC and a decrease of stress level of about 57% compared to the original when being exposed to 10kN, and the result in displacement is ¼ of the original concept when being exposed to 100kN.

    The conclusion of this work is that a significant improvement can be made by adding thickness to the cross-section, but it is limited by the strength of the screws and the attachment. The ECC can handle up to 100kN before it will reach the electrical contacts, but the screws can only endure up to 53kN before they rupture. The screws and the attachment are the ones limiting what the electrical coupler can handle, but if the real force of an impact is below 53kN, this solution could be seen as acceptable in terms of the strength.

    The concept also involves a significant addition of weight and space required. The weight (+2,4kg) needs to be examined so it doesn’t affect other parts of the coupler negatively, and evaluation needs to be done to find out if the space required (+12mm at the center of the ECC) is available and that the meeting electrical couplers won’t collide in each other when connecting.

    A suggestion is to focus on the avoidance of short circuit, rather than the avoidance of reaching the electrical contacts. A more potential solution could potentially be found in a protective coating, which will allow the ECC to deform and not exhaust the screws and the attachment as much. The thicker and stronger geometry of the ECC will set higher requirements for the screws and the attachment. 

  • 29.
    Andersen, Martin
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. Chalmers University of Technology, Gothenburg.
    Solar District Heating for Low Energy Residential Areas: A Technical Analysis of Heat Distribution Concepts for a Solar Assisted District Heating System2019Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The integration of a solar thermal system into a district heating network can be a cost-effective solution, especially for new low-energy residential areas. Because of this, many new small solar district heating systems are built at the same time as the buildings, allowing for a more holistic approach to the design and construction. In doing so, it is possible to optimise the integration of the solar thermal system with respect to both cost and technical layout. This thesis presents studies that aim to investigate the most energy efficient distribution concept for successful implementation of solar district heating technology. An existing solar assisted district heating system is modelled in simulation software and the distribution system is varied in order to find out whether there is a more energy efficient option. Three system concepts are investigated: 1. A Hybrid system using a combination of high-temperature, conventional steel pipe primary culvert, intermediate substations containing solar buffer stores and a low-temperature, EPSPEX secondary culvert with DHW-circulation (so-called GRUDIS).2. A Conventional distribution system with steel pipes, higher operating temperatures and centralized solar buffer stores.3. An All GRUDIS system, using only EPSPEX distribution with DHW-circulation, lower operating temperatures and centralized solar buffer stores.A sensitivity analysis is performed by simulating the three different distribution system for various linear heat densities, with the added objective of detecting any range-bound limitations of the different distribution systems. Results indicate that both the hybrid and All GRUDIS distribution concept is preferable to conventional DH distribution regardless of the network heat density. The hybrid concept seems preferable in denser district heating networks, but results are inconclusive regarding the best concept for sparser networks. Preliminary economic considerations show that the initial investment costs may be reduced by changing from a Hybrid to an All GRUDIS distribution concept, although a more detailed analysis is needed to draw conclusions about the most economical solution.Keywords: District heating, solar thermal, simulation, renewable energy, 4DH.

    Fulltekst (pdf)
    fulltext
  • 30.
    Andersen, Martin
    et al.
    Högskolan Dalarna, Institutionen för information och teknik, Energiteknik. Dept. of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg.
    Bales, Chris
    Högskolan Dalarna, Institutionen för information och teknik, Energiteknik.
    Dalenbäck, J. -O
    Economic Analysis of Heat Distribution Concepts for a Small Solar District Heating System2022Inngår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 13, artikkel-id 4737Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One challenge in today’s district heating systems is the relatively high distribution heat loss. Lowering distribution temperatures is one way to reduce operational costs resulting from high heat losses, while changing the distribution system from steel pipes to plastic pipes and changing the heat distribution concept can reduce investment costs. The result is that the overall life cycle cost of the district heating system is reduced, leading to the improved cost competitiveness of district heating versus individual heating options. The main aim of this study was to determine the most cost-efficient distribution system for a theoretical solar district heating system, by comparing the marginal life cycle cost of two different distribution systems. A secondary aim was to determine the influence of the employed pipe type and insulation level on the marginal life cycle cost by comparing detailed economic calculations, including differences in pipe installation costs and construction costs, among others. A small solar-assisted district heating system has been modeled in TRNSYS based on a real system, and this “hybrid” model is used as a basis for a second model where a novel distribution system is employed and the heating network operating temperature is changed. Results indicate that a novel distribution concept with lower network temperatures and central domestic hot water preparation is most efficient both from an energy and cost perspective. The total life cycle costs vary less than 2% for a given distribution concept when using different pipe types and insulation classes, indicating that the investment costs are more significant than operational costs in reducing life cycle costs. The largest difference in life cycle cost is observed by changing the distribution concept, the novel concept having approximately 24% lower marginal life cycle cost than the “hybrid” system. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

    Fulltekst (pdf)
    fulltext
  • 31.
    Andersson, Carolin
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Från oljehydraulik till vattenhydraulik: Utveckling av ett portabelt hydraulikaggregat2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Rapporten beskriver arbetet bakom utvecklingen av ett portabelt vattenhydrauliksystem som ska användas till att öppna och stänga en dammlucka om det ordinarie hydrauliksystemet som används till detta är ur funktion. Syftet var att uppnå samma prestanda som ett portabelt oljehydrauliksystem vilket också gick att åstadkomma med undantaget att olja inte gick att undvika helt.

    Arbetet utfördes i samarbete med företaget Mobin Hydraulic AB som utvecklar hydrauliska system för att öppna och stänga dammluckor. Mobin är specialiserade på vattenhydraulik som är ett mer miljövänligt alternativ i jämförelse med oljehydraulik. Eftersom ett intresse också fanns på marknaden där miljövänliga lösningar efterfrågades allt mer var det portabla vattenhydrauliksystemet av intresse för både Mobin och för marknaden.

    Problematiken i arbetet kretsade kring hur flödet skulle styras och vilken pump och hydraulmotor som kunde användas i systemet. Komponenterna skulle vara anpassade för vatten och harmoniera med en förbestämd bensinmotor samtidigt som önskad prestanda levererades.

    Genom att studera hydraulik och vattnets egenskaper och påverkan på det hydrauliska systemet i kombination med att ta del av Mobins erfarenheter skapades en bild över systemets uppbyggnad och vilka komponenter som önskades.

    Utifrån en komponentsökning, utförda beräkningar och genom en konceptutformning gjordes ett konceptval där de valda komponenterna, komponenternas dimensioner och placeringar i systemet framgick. Till följd av den begränsade tillgången på komponenter inom vattenhydrauliken användes växellådor för att få ut rätt varvtal och moment. En av växellådorna innehöll olja och därför gick det inte att undvika oljeanvändningen helt.

  • 32.
    Andersson, David
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Effektiviserad balresthantering2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Arctic Paper Grycksbo är ett företag som tillverkar papper med inköpt pappersmassa. Denna pappersmassa anländer till företaget i form av massabalar, inslagna i ett så kallat omslagspapper som även det går att använda för att tillverka papper. Skador på balar till följd av transport och hantering gör att användbar pappersmassa avlägsnas från balen och hamnar på marken. Papperet plockas upp och placeras i en återvinningscontainer av de som arbetar på massamottagningen. Containern ska sedan tömmas och återvinnas.

    Då den nuvarande återvinningsrutinen visat sig behöva ekonomisk och ekologisk förbättring, så finns ett behov av att antingen förbättra metoden/rutinen för att återvinna papperet, eller att förhindra att balresterna lossnar. Syftet med arbetet är att ta reda på vilka möjligheter som finns till förbättring.

    Kartläggning och beräkningar av återvinningspotentialer och kostnader för nuvarande sättet att ta hand om balresterna har därför tagits fram. Dessa ligger till grund för vart störst förbättringspotential finns och baserat på denna så har olika konceptförslag tagits fram.

    Med hjälp av resultatet från kartläggningen har ett nytt sätt att hantera återvinningen av papperet tagits fram i samråd med tekniker på företaget. Den nya metoden möjliggör ett sätt att förenkla den nuvarande rutinen och minska kostnaderna samt underlätta för de involverade.

  • 33.
    Andersson, Grober
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Framdrivningssystem för Articulated Funiculator i SL deep station: Framtagning och urval av koncept2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Det här examensarbetet har genomförts i samarbete med Tyréns i projektet Articulated Funiculator som utvecklar framtidens vertikala transportsystem som i det här fallet är tänkt att användas i SL deep station i Stockholm.Syftet med det här arbetet är att är att ta fram framdrivningskoncept för Articulated Funiculator och genom konceptval sortera ut det optimala för SL deep station. För att nå syftet har studier företagits av litteratur samt rapporter som följts av workshops och kundundersökningar. Sedan har en parvis jämförelse gjorts, QFD, konceptgenerering och ett tvåstegs konceptval genomförts.Resultat är att det optimala framdrivningssystemet för SL deep station i Stockholm är ett system med linjärmotorer som är monterade mellan spåren.

  • 34.
    Andersson, Ing-Marie
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Arbetsvetenskap.
    Hedlund, Ann
    Högskolan Dalarna, Akademin Industri och samhälle, Arbetsvetenskap.
    Rosén, Gunnar
    Högskolan Dalarna, Akademin Industri och samhälle, Arbetsvetenskap.
    Ökad förståelse bland företagsledare för nyttan av utvecklingsinsatser inom arbetsmiljöområdet2011Rapport (Annet vitenskapelig)
    Abstract [sv]

    Sammanfattning Föreliggande rapport avser en delstudie inom projektet Attraktiv Konkurrenskraft (AKK) Syftet med detta arbete är att utvärdera fem metoder som kan ”väcka insikt” om nyttan av att starta utvecklingsaktiviteter för att bättre ta tillvara de mänskliga resurserna i arbetet. Baserat på detta ska en metod väljas för fördjupade studier. Drivkrafterna för att skapa bra arbetsmiljöer är många. Den primära kan sägas vara den humanitära drivkraften. Förutom de överväganden som ligger till grund för arbetsmiljölagstiftning och avtal mellan arbetsmarknadens parter finns alltså goda skäl för företagare att prioritera arbetsmiljöarbete. Den fråga som berörs i detta arbete är i vad mån det är möjligt att genom enkla insatser påverka en arbetsmiljöansvarig chefs benägenhet att gå till beslut om att genomföra insatser för att utveckla förutsättningarna för att bättre nyttja de mänskliga resurserna i organisationen. Målet är att chefen bestämmer sig för att påbörja en beslutsprocess om utvecklingsaktiviteter för att ta tillvara de mänskliga resurserna i arbetet vilket ökar förutsättningarna att rekrytera, behålla och engagera kompetent personal. Som resultat av förstudien har fem olika insiktsmetoder utvecklats och anpassats. Dessa metoder har kallats GAP-analys, Fokusgrupper Attraktivt Arbete, Visit, Riskanalys och Scenario. De tio företagen som deltog hade mellan 11 och 39 anställda, och deras verksamheter var inom områdena tillverkning, reparation och underhåll. Resultat från användning av metoderna visar att alla metoderna uppfyller kriterierna att vara enkla att förstå och snabba att genomföra. Fokusgrupper, Visit och Riskanalys ger konkret vägledning för fortsatt utvecklingsarbete. Fokusgrupper ger ett brett underlag för en fortsättning som bygger på dialog, en djupare analys på individnivå samt har psykiska och sociala dimensioner. Därmed sågs Fokusgrupper som den mest intressanta metoden att gå vidare med. Denna studie indikerar att det finns möjlighet att påverka ledare att ta beslut om aktiviteter för att utveckla den mänskliga resursen. Det finns därmed anledning att ytterligare studera ett antal företag där en och samma metod används. Valet har fallit på Fokusgrupper, även om andra metoder skulle vara tänkbara. Abstract This report concerns a sub-study of the project attractive competitiveness (AKK). The aim of the work is to evaluate five methods that are supposed to” raise awereness” about the advantages of initiating activities to better utilize human resources at work. Based on that shall one method be elected for depend studies. The driving forces for creation of good work environments are many. The primary can be said to be the humanitarian driving force. Except for the considerations that are behind the work environment legislations and agreements between social partners is therefore good reasons for entrepreneurs to give priority to work environment work. The focus of this study is to which extent it is possible by a limited input influence the liability of a manager with responsibilities for the work environment to take decisions to start a process aimed at improving the use of the human resources in the company. The goal is that the manager decides to start such a process which also is supposed to recruit, retain and engage competent staff. In the sub-study have five insight methods been developed or adapted. Those methods have been named gap-analysis, focus groups attractive work, visit, risk analysis, and scenario. The ten participating companies employed between eleven and thirty-nine persons. The companies represented different branches as production, repair work and maintenance. The results from the test of the methods shows that they all meet the criteria’s to be simple to understand and quick to carry through. Focus groups attractive work, visit, and risk analysis gives substantial guidance for further development work. Focus groups attractive work gives a broad base for a continuation built on a dialogue, a deeper analyses of individual level as well as mental and social dimensions. Of that reason chosen for deepened studies. This study indicates that there are possibilities to influence managers to decide about activities aimed at better use of human resources. There are therefore reasons to make further studies in a number of companies where the elected method is used.

    Fulltekst (pdf)
    FULLTEXT01
  • 35.
    Andersson, Ing-Marie
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Arbetsvetenskap.
    Rosén, Gunnar
    Högskolan Dalarna, Akademin Industri och samhälle, Arbetsvetenskap.
    Hedlund, Ann
    Högskolan Dalarna, Akademin Industri och samhälle, Arbetsvetenskap.
    PIMEX 2008 for the aluminium industry. Visualised training material and manual.2008Rapport (Annet vitenskapelig)
    Abstract [en]

    PIMEX in the aluminiumindustry. It is not always self-evident what should be done to minimize the elements that create problems in the work environment. Which initiatives are most effective in improving the air quality? How can we decrease noise and vibration? How should we work in order to decrease the risk of strain injuries? Often is it possible to significantly reduce these risks without bigger investments, simply by making these hazards visible. The PIMEX-method does this clearly by simultaneously filming and monitoring the workplace so that such hazards – air pollutants, for example – can be traced. PIMEX has shown itself to be an effective tool for implementing work environment improvements.

  • 36.
    Andersson, Martin
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Konceptutvärdering av gjutformshantering: Utformning och dimensionering av entresolplan enligt eurocode2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Vid ABB Components i Ludvika tillverkas genomföringar till transformatorer. Under tillverkningen av dessa genomföringar används ett antal gjutformar. Gjutformarna lagras på ett entresolplan uppbyggt av ett antal pelare och balkar. Mängden gjutformar ökar och har lett till att nuvarande sätt att hantera och lagra dessa gjutformar på ej fungerar ur ett personsäkerhet- och effektivitetsperspektiv. ABB har fått två koncept på hur dessa problem kan lösas. Ett koncept som använder sig av ett kulgov. Det andra är ifrån ELE Engineering AB som föreslår att ett skensystem monteras i undersidan av entresolplanet vilket skapar plats för 60st nya gjutformar. Detta arbete syftar till att utreda hur entresolplanet påverkas av ELEs förslag, hur det ska förstärkas samt att utreda vilket av koncepten som är att föredra.

    Genom olika simuleringar föreslås att entresolplanet förstärks med 21st nya sekundärbalkar och 5st pelare för att klara den belastning som gjutformarna ger upphov till. Den harmoniserade standarden EN-1090 har legat till grund för hur dessa pelare och sekundärbalkar som föreslås ska utformas och infästas. Som lösning rekommenderas ELEs koncept baserat på en konceptjämförelse trots brist på tillräckligt information kring kulgolvet.

  • 37.
    Arguello, Nicolay
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Iñiguez, Enric
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Renewable Energy Emergency Microgrid Optimization in Ludvika2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In the community of Ludvika, a Renewable Energy Emergency Microgrid (REEM) has been defined to provide back-up power during crisis situations. An Energy Storage System (ESS) was designed to support the main loads of the Microgrid in the first working hours. Additionally, the ESS will start-up the hydro power station, which will replace the power supply from the battery after the set-up period. However, the necessity of understanding the operation of the major components, such as the photovoltaic (PV) system and the ESS, of the REEM in normal conditions is imperative.

    This study analyses a variety of scenarios to evaluate how the renewable energy of an isolated system can be managed. Alternatives for increasing self-consumption of PV power and reduce feed-in power in the REEM are investigated. All the solutions consider the complete system design and an additional economic analysis for supporting the decision-making. The results show that selling the energy to the grid is the best economic solution, followed by the distribution of energy. However, the difference of 0.5 % in the total net present cost (TNPC) makes the distribution system, including the ESS, an option to be considered. In the upcoming years, changes on the amount of energy produced by the PV system or increasing the battery capacity usage in normal operation can become more feasible.

  • 38.
    Argårds, Andreas
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Kartläggning av ytjämnheten efter kallvalsning för olika kallvalsade kvalitéer samt trimvalsningens påverkan på ytjämnheten2010Independent thesis Basic level (degree of Bachelor)Oppgave
    Abstract [sv]

    Syftet med detta arbete är att kartlägga ytjämnheten på stålbanden efter kallvalsning samt hur den erhålla ytjämnheten påverkas av trimvalsningen. Detta för att undersöka om det är möjligt att minska ner användandet av någon valsyta i Tandemverket vid SSAB Borlänge. Genom att mäta ytjämnheten på stålband av olika kallvalsade kvalitéer efter kallvalsning och trimvalsning, mäta ytråheten på texturerade valsar före och efter användning samt genomföra test med nya ytkombinationer har ett antal resultat genererats. Två test där Docol 200 band som skulle levereras med bandyta 23 valsades med en grövre yta i Tandem (valsyta 48 istället för 34) än vad som är brukligt och sedan trimvalsades med ordinarie valsyta visade att det är möjligt att klara kraven på Ra-värde för bandyta 23 även på band som kallvalsats med en grövre valsyta än i vanliga fall. Dock är det inte säkerställt att kraven för yta 23 alltid kan uppnås på band kallvalsade med grövre valsyta. Trimvalsning med valsyta 57 i den kontinuerliga glödgningslinjen har ingen betydande påverkan på ytjämnheten för Docol 600 & 800 DP, dock påverkar den ytan för Docol 200 eftersom att dessa band har mindre spridning i Ra-värde efter trimvalsning jämfört med innan. Trimvalsning med valsyta 57 höjer toppantalet på bandens yta. Band av en högre hållfasthetsklass får lägre Ra-värde jämfört mot mjukare stålsorter. Band med stor tjockleksreduktion i Tandem får lägre Ra-värde, detta gäller speciellt Docol 200 där trenden är tydligast. Ra-värdet på de texturerade valsarna i Tandem sjunker mycket i början när de används, test har visat att redan under kalibreringen kan Ra-värdet minska med 0,8 µm – 1,3 µm.

    Fulltekst (pdf)
    FULLTEXT01
  • 39.
    Arumugam, Vijay
    Högskolan Dalarna, Institutionen för information och teknik.
    Techno-economic study of second-life EV batteries as alternative energy storage and comparison with lead-acid and new Li-ion batteries in off-grid PV systems2022Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The global EV stock is expected to increase from 7.2 million in 2019 to nearly 140 million vehicles by 2030. So, the demand for the battery also increases due to the increase in the number of EVs. In any EV, battery degradation is an unavoidable phenomenon and EV batteries are assumed to arrive at their end-of-life in EV application when the state of health reaches 80 %, repurposing the eligible EV batteries after end of first life is expected to extend their lifetime by another 5-15 years in the second life applications. 

    This thesis aims to conduct a techno-economic study on the usage of second life EV batteries as an alternative storage option in off-grid PV systems compared to lead-acid batteries and new Li-ion batteries. A single-family house with an annual demand of 2245 kWh/year located in Athens was chosen as the primary location, the off-grid PV system is pre-sized for Athens and based on the pre-sizing results and what is state of art in the market. The system components were chosen for system design (4 kW bi-directional inverter, 2.9 kW PV array, 7.2 kW genset and three battery bank options i.e., 16.5 kWh of lead-acid, 8 kWh new Li-ion and 12.6 kWh of second life EV battery). PV off-grid system with different storage options is simulated using HOMER for both locations and the results are compared. 

     The simulation results show that the designed off-grid PV system can reach a solar fraction of 90 % in Athens and 73 % in Gotland when 16.5 kWh of lead-acid batteries are used with an allowed depth of discharge of 50 %. When a new Li-ion battery of 8 kWh with an allowed depth of discharge of 80 % is used then the achievable solar fraction is 84 % in Athens and 71 % in Gotland, When the second life EV battery of 12.6 kWh with an allowed depth of discharge of 60 % is used then the achievable solar fraction is 90 % in Athens and 74 % in Gotland. Sensitivity analysis is performed on the depth of discharge and results showed that the solar fraction can be increased by allowing the battery to discharge more, but it also decreases the battery lifetime. 

     The simulation results also show that the net present cost was lower in Athens for all the reference cases compared to Gotland. Net present cost and levelized cost of electricity for the off-grid system are 25.3 k€, 0.9 €/kWh in Athens and 29.2 k€, 1.0 €/kWh in Gotland when a lead-acid battery is used. When a new Li-ion battery is used then 26.2 k€, 0.9 €/kWh in Athens and 29.3 k€, 1.0 €/kWh in Gotland, when the second life EV battery is used then 26.7 k€, 0.9 €/kWh in Athens and 30.7 k€, 1.1 €/kWh in Gotland. 

     Overall, the net present cost and levelized cost of electricity are lower in Athens in all cases compared to Gotland. For the reference house in Athens, lead acid battery system has shown slightly lower net present cost than new Li-ion battery and second life EV battery. For the reference house in Gotland, both lead acid battery and new Li-ion battery system have shown similar net present cost and they are slightly lower than second life EV battery.  

    Also, the second life EV battery levelized cost of electricity is fairly comparable to the new Li-ion and lead acid battery system. In future, the massive inflow of used batteries from EV are expected to be available on the market for the second life application at a lower price than today. Thus, in future, second life EV batteries can become economically viable.

    Fulltekst (pdf)
    fulltext
  • 40.
    Ashibuogwu, Ruth
    Högskolan Dalarna, Institutionen för kultur och samhälle.
    An Environmental and Health Benefit and Cost analysis of Renewable Energy in Nigeria: A comparison between the investment in solar energy plant and hydropower plant2024Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study analyses the environmental and health benefits associated with the use of renewable energy sources, focusing on the costs and savings involved. The research employs a comprehensive cost-benefit analysis approach, comparing the costs associated with generating energy from a 10 megawatts solar energy power plant versus a 10 megawatt hydropower plant. The data used in this research was gathered from a variety of sources, including government reports, academic studies, and industry publications. The analysis ensued a positive net benefit for both power plants, while the economic useful life of developing and implementing the solar plant is shorter, the long-term benefits of these technology outweighs that of the hydro power plant. The data indicates that renewable energy technologies can significantly reduce greenhouse gas emissions and air pollution, leading to substantial improvements in public health and environmental quality. Overall, this research indicates that investing in renewable energy sources is not only an environmentally responsible choice, but also a viable decision for the society. 

    Fulltekst (pdf)
    fulltext
  • 41.
    Ashraf, Ali Junaid
    Högskolan Dalarna, Akademin Industri och samhälle, Elektroteknik.
    DC Motor Speed Control via Fuzzy / Pole Placement / PI Controller2010Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This report presents a new way of control engineering. Dc motor speed controlled by three controllers PID, pole placement and Fuzzy controller and discusses the advantages and disadvantages of each controller for different conditions under loaded and unloaded scenarios using software Matlab. The brushless series wound Dc motor is very popular in industrial application and control systems because of the high torque density, high efficiency and small size. First suitable equations are developed for DC motor. PID controller is developed and tuned in order to get faster step response. The simulation results of PID controller provide very good results and the controller is further tuned in order to decrease its overshoot error which is common in PID controllers. Further it is purposed that in industrial environment these controllers are better than others controllers as PID controllers are easy to tuned and cheap. Pole placement controller is the best example of control engineering. An addition of integrator reduced the noise disturbances in pole placement controller and this makes it a good choice for industrial applications. The fuzzy controller is introduce with a DC chopper to make the DC motor speed control smooth and almost no steady state error is observed. Another advantage is achieved in fuzzy controller that the simulations of three different controllers are compared and concluded from the results that Fuzzy controller outperforms to PID controller in terms of steady state error and smooth step response. While Pole placement controller have no comparison in terms of controls because designer can change the step response according to nature of control systems, so this controller provide wide range of control over a system. Poles location change the step response in a sense that if poles are near to origin then step response of motor is fast. Finally a GUI of these three controllers are developed which allow the user to select any controller and change its parameters according to the situation.

    Fulltekst (pdf)
    FULLTEXT01
  • 42. Attri, Shubham Dutt
    et al.
    Singh, Shweta
    Dhar, Atul
    Powar, Satvasheel
    Högskolan Dalarna, Institutionen för information och teknik, Energiteknik. Indian Institute of Technology Mandi, Himachal Pradesh, India.
    Multi-attribute sustainability assessment of wastewater treatment technologies using combined fuzzy multi-criteria decision-making techniques2022Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 357, artikkel-id 131849Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water, which is predicted to be one of the most critical resources for the near future, also plays a vital role in society's sustainable development. Wastewater treatment is a critical part of the circular water management system and offers various technological alternatives. Taking appropriate decision for the technology selection is, therefore, essential for a long-term perspective. A complex yet imperative process is the sustainable selection of the wastewater treatment process. This paper presents the use of multi-criteria decision-making (MCDM) in the sustainability assessment of wastewater treatment technologies that may be very relevant to the growing sector with many emerging options. A comparison of six wastewater treatment technologies based on four sustainability parameters using three MCDM techniques, namely FSWARA, FMOORA and FTOPSIS is presented in detail. FSWARA is used for weighting criteria and the other two for technology ranking. The detailed step-by-step comparison study is presented and the results were somewhat predictable for the study, and this confirms the reliability of the methodology. This paper's primary objective is to propose a well-defined increscent practice for making sustainable wastewater treatment decisions among state-of-the-art technologies.

    Fulltekst (pdf)
    fulltext
  • 43.
    Awda, Fadi
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik.
    Omkonstruktion av luftkylning för enfasreaktor2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Uppgiften för detta examensarbete var att undersöka överslag för tre reaktorenheter på grund av fukt och smuts som förts in i reaktorn genom kylsystemet. Syftet var att ta fram en lösning som ger reaktorn möjlighet att vara aktiv utan att påverkas av den mängd fukt och smuts som finns i omgivningen.

    Företaget hade inte resurser att ta fram en lösning på kort tid så både tid och kostnad en stor faktor i uppgiften. De krav som kunden har är att samtliga detaljer ska monteras på plats och att det inte påverkar hallarna där reaktorerna idag befinner sig. För att ta fram lösningar behövde reaktorns funktioner brytas ner i enklare delar, sedan valdes koncept som antingen påverkar miljön runtomkring eller konstruktionen av reaktorn.

    Den säkerhet kunden vill ha är att kylning ska vara minst lika effektiv i den nya lösningen och att vi åtgärdat det som orsakat haveriet, vilket var en blandning av smuts och fukt. Valen av lösningar blev; en lösning att lägga in övervakningsutrustning i reaktorn för temperaturövervakning, dessutom valdes en ny konstruktion för att dra om kylningens luftflöde och därmed undvika att fukt bildas inne i reaktorn och risk för överslag.

  • 44.
    Aylott, Benjamin
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Techno-Economic Evaluation of Distributed Generation within a Community Smart Grid with Demand Side Response Using HOMER2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this study the distributed generation of renewable energy, primarily photovoltaic power, and consumption of energy within a geographically dispersed smart grid or ‘virtual micro grid’ is simulated using a model based around the HOMER Pro software with the aim of gaining insight into the economic and environmental performance of the system under different assumptions about the configurations of the generators and the presence of low carbon technologies such as heat pumps and electric vehicles. Demand side response for the purpose of reducing carbon emissions was also investigated as part of this.

    As well as simulating the system within HOMER, the study involved constructing a representative load profile for 200 domestic consumers and other loads using existing data, implementing a model for demand side response, using a range of detailed technical and environmental data to configure the HOMER model, and creating custom plotting tools. These features were connected in a data analysis pipeline written in Python included as part of the submission.

    The study found that to improve the environmental and economic performance of the system increasing the amount of renewable generation should be prioritized over other measures, such as demand side response. PV was the easiest to add due to lower upfront costs (compared to battery storage systems and mid-scale wind turbines) and lower financial and regulatory overheads. Carbon emissions were found to be minimized for around 3.5kW of PV per household in this scenario. Including a single mid-scale wind turbine was found to have the potential to greatly increase renewable penetration, and reduce carbon emissions and the cost of energy due to the complementary nature of PV and Wind power production. Battery storage at low penetrations was found to have little impact, but can make a large impact at high penetration but at significant financial expense.

    A range of battery products was also investigated for their suitability for use within the project and future schemes and were evaluated by locating them in the Renewable Fraction/LCOE plane.

    The inclusion of low carbon technologies such as heat pumps and electric vehicles was found to have some negative impact on the performance where only PV is present in the smart grid with little evidence that it can make better use of the renewable power due to poor matching with the available PV generation.

  • 45.
    Azizoğlu, Yağız
    Högskolan Dalarna, Akademin Industri och samhälle, Materialteknik. Luleå University of Technology.
    Modeling of Cold Pilgering of Tubes2017Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Cold pilgering is a challenging tube forming process in terms of modeling due to the complexity in kinematic of tools, friction condition and material behavior. The process development has mostly been based on simple formulas and costly full-scale tryouts. The aim in this study is to develop validated Finite element models of cold pilgering to increase the understanding of influence of the process parameters on the produced tubes.

    In the course of this thesis, three-dimensional mechanical and thermo-mechanical Finite element models of cold pilgering were developed. The commercial code MSC.Marc was used in the simulations. General 3D models are needed to be able to capture asymmetric deformation in cold pilgering. It was found that tool deflections together with elastic deformation of roll dies have considerable influence on the rolling force. Furthermore, the strain rate and temperature effects on the response of the material and thereby on the rolling force were evaluated.

    Fulltekst (pdf)
    fulltext
  • 46.
    Azizoğlu, Yağız
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Materialteknik. Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Gärdsback, Mattias
    Sandvik Materials Technology, R&D, Sandviken..
    Sjöberg, Bengt
    Sandvik Materials Technology, R&D, Sandviken..
    Lindgren, Lars-Erik
    Luleå University of Technology.
    Finite element analysis of cold pilgering using elastic roll dies2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A finite element model of cold pilgering with elastic roll dies have been developed and used to investigate the influence of roll die deformation on the material flow, contact region, roll separating force and tube dimensions. Full scale experiments were performed to validate the contact surface and tube dimensions. The results show that the influence of roll die flattening is not significant on the contact length. However, elastic deformation of roll die has strong influence on both the wall thickness reduction and roll separating force. Thus it is recommended to consider elasticity of roll dies when forces and tube dimensions are estimated.

    Fulltekst (pdf)
    fulltext
  • 47.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    ClimateWell TDC with District Heat2010Rapport (Annet vitenskapelig)
    Abstract [en]

    The PolySMART demonstration system SP1b has been modeled in TRNSYS and calibrated against monitored data. The system is an example of distributed cooling with centralized CHP, where the driving heat is delivered via the district heating network. The system pre-cools the cooling water for the head office of Borlänge municipality, for which the main cooling is supplied by a 200 kW compression chiller. The SP1b system thus provides pre-cooling. It consists of ClimateWell TDC with nominal capacity of 10 kW together with a dry cooler for recooling and heat exchangers in the cooling and driving circuits. The cooling system is only operated from 06:00 to 17:00 during working days, and the cooling season is generally from mid May to mid September. The nominal operating conditions of the main chiller are 12/15°C.

    The main aims of this simulation study were to: reduce the electricity consumption, and if possible to improve the thermal COP and capacity at the same time; and to study how the system would perform with different boundary conditions such as climate and load.

    The calibration of the system model was made in three stages: estimation of parameters based on manufacturer data and dimensions of the system; calibration of each circuit (pipes and heat exchangers) separately using steady state point; and finally calibration of the complete model in terms of thermal and electrical energy as well as running times, for a five day time series of data with one minute average data values. All the performance figures were with 3% of the measured values apart from the running time for the driving circuit that was 4% different. However, the performance figures for this base case system for the complete cooling season of mid-May to midSeptember were significantly better than those for the monitoring data. This was attributed to long periods when the monitored system was not in operation and due to a control parameter that hindered cold delivery at certain times. 

    Fulltekst (pdf)
    fulltext
  • 48.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    European resarch school on large scale solar thermal - SHINE2014Inngår i: Solar District Heating 2014, Hamburg, Germany, 2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The Solar HeatIntegration NEtwork (SHINE) is a European research school in which 13 PhDstudents in solar thermal technologies are funded by the EU Marie-Curie program.It has five PhD course modules as well as workshops and seminars dedicated to PhDstudents both within the project as well as outside of it. The SHINE researchactivities focus on large solar heating systems and new applications: ondistrict heating, industrial processes and new storage systems. The scope ofthis paper is on systems for district heating for which there are five PhDstudents, three at universities and two at companies. The PhD students allstarted during the early part of 2014 and their initial work has concentratedon literature studies and on setting up models and data collection to be usedfor validation purposes. The PhD students will complete their studies in2017-18.

    Fulltekst (pdf)
    fulltext
  • 49.
    Bales, Chris
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Andersen, M.
    Bava, F.
    Louvet, Y.
    Peréz de la Mora, N.
    Sotnikov, A.
    Shantia, A.
    SHINE Doctoral School: Results from six PhD studies on large scale solar thermal2016Inngår i: 4th International Solar District Heating Conference, 2016Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The Solar Heat Integration NEtwork (SHINE) is a European research school in which 13 PhD students in solar thermal technologies are funded by the EU Marie-Curie program. It has five PhD course modules as well as workshops and seminars dedicated to PhD students both within the project as well as outside of it. The SHINE research activities focus on large solar heating systems and new applications: on district heating, industrial processes and new storage systems. The scope of this paper is on systems for district heating for which there are six PhD students, five at universities and one at a company. The initial work concentrated on literature studies and on setting up initial models and measurement setups to be used for validation purposes. The measurements have been used for validating simulation models, including those used for extending the capabilities of the planning tool Polysun to simulate smaller district heating systems. Some results of these studies are presented in the paper. The PhD students will complete their studies in 2017-18.

  • 50.
    Bales, Chris
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Gustafsson, Marcus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Chiara, Dipasquale
    Roberto, Fedrizzi
    Alessandro, Bellini
    Matteo, D’Antoni
    Fabian, Ochs
    Georgios, Dermentzis
    Sarah, Birchall
    D2.1c Simulation Results of Reference Buildings2014Rapport (Annet vitenskapelig)
    Abstract [en]

    This report is the third part of the deliverable D2.1, where the other two parts report on the energy consumption in the building stock in Europe based on the available energy statistics (D2.1a) and the energy policies related to buildings (D2.1b).The aim of this report is to give complementary information about the heating and cooling demands of residential and office buildings based on simulations, so that the many gaps in the energy statistics can be filled and the statistics can be critically evaluated. The methodology results in a complete and consistent overview of the heating and cooling demands in residential and office buildings for seven different climate regions covering the whole of the EU and six different periods of construction, covering pre-1945 to post 2000. In addition, the data for the residential building stock is split into single family houses, small and large multifamily houses, while for offices the results are given for low and high rise offices with 6 or 12 office units per floor.The simulation models have been benchmarked (calibrated) against the energy statistics for each of the seven climate regions based on the aggregated data for the whole residential building stock and then for the office building stock in that climate region (in D2.1a). The methodology derives the aggregated average using weighted averages of data split into periods of construction and typology for both energy statistics and simulation results. The weighting is done based on heated and cooled floor area. As nearly all of the energy statistics are given in terms of consumption, while simulation results were calculated as demand, the demand data were converted to consumption data. One fixed conversion factor was used for heating (average efficiency 0.8) and one for cooling (average EER 2.5). Since the calculated demands strongly depend on the imposed heating or cooling set temperatures, this simulation parameter was varied so that the aggregated simulation result was the same as that for the consumption derived from the energy statistics. The calibrated models were then used to derive the average heating and cooling consumptions of the building stock in the seven climate regions.The methodology has a number of uncertainties, both in terms of the energy statistics as well as in terms of the simplifications and assumptions in the simulation models. During the calibration process a number of inconsistencies have been detected for individual countries and climate regions between simulation results and energy use from statistic data. The mismatches are analytically assessed, showing improvements necessary both in terms of statistic data necessary for reliable energy estimations and data to be gathered in order to guarantee consistent simulations outcomes.Beside the building stock survey completion and statistic data quality assessment, the work is also the basis for the definition of suitable Energy Renovation Packages and Products within the iNSPiRe project. The simulation results will be used to identify which building typologies, periods of construction and climate region have the largest potential for impact on the European scenario. Such information will be used within the iNSPiRe project to define reference Target buildings, as virtual demonstration cases to prove the potential improvements and impacts following the renovation process of a given share of the European building stock.

1234567 1 - 50 of 728
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf