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  • 1.
    Abor, Joshua Yindenaba
    et al.
    Centre for Global Finance, SOAS University of London, United Kingdom; University of Stellenbosch Business School, South Africa.
    Karimu, AminUmeå University, Faculty of Social Sciences, Centre for Environmental and Resource Economics (CERE). Environmental Policy Research Unit (EPRU), University of Cape Town, South Africa.
    Sustainability management in the oil and gas industry: emerging and developing country perspectives2023Collection (editor) (Refereed)
    Abstract [en]

    The oil and gas industry is a complex sector with significant reach in terms of providing the energy needs of the global economy and the security, environmental and development consequences thereof. In particular, the sector is extremely important for the economic growth of emerging markets and developing countries. Furthermore, the life span of oil and gas resources is finite, with high health and safety risks and substantial environmental costs that require careful management and sustainability practices to ensure optimal extraction and utilisation of these resources. This book examines the challenges and opportunities in the oil and gas industry, in the context of emerging markets and developing economies. It provides comprehensive coverage of the management and sustainability practices of the sector, the environmental impact and sustainability of resources as well as the businesses that operate in the sector across the entire value chain. It addresses the current discourse on topics such as the Sustainable Development Goals, the Green Economy, the Paris Agreement and Glasgow Climate Pact and concludes with a chapter on the future of the oil and gas industry. The discussions around energy and energy transitions in particular continue to gain momentum and the book provides a wide-reaching and up-to-date overview of the industry. The book introduces readers to the concepts and formal models of analysis in the oil and gas sector and will serve as a useful resource for students, scholars and researchers in operations, marketing, procurement and supply chain management, project management, health and safety management, environmental economics, natural resource economics, development finance, and development studies. Researchers and practitioners working in these areas will also find the book a useful reference material.

  • 2.
    Abugabbara, Marwan
    et al.
    Department of Building and Environmental Technology, Division of Building Services, Lund University, Lund, Sweden.
    Gehlin, Signhild
    The Swedish Geoenergy Center, Lund, Sweden.
    Lindhe, Jonas
    Department of Building and Environmental Technology, Division of Building Services, Lund University, Lund, Sweden; Alfa Laval Corporate AB, Lund, Sweden.
    Axell, Monica
    RISE Research Institute of Sweden, Gothenburg, Sweden.
    Holm, Daniel
    Vasakronan AB, Stockholm, Sweden.
    Johansson, Hans
    Umeå ProjektEnergi AB, Umeå, Sweden.
    Larsson, Martin
    RISE Research Institute of Sweden, Gothenburg, Sweden.
    Mattsson, Annika
    Granitor Properties, Malmö, Sweden.
    Näslund, Ulf
    Vasakronan AB, Stockholm, Sweden.
    Puttige, Anjan Rao
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Berglöf, Klas
    ClimaCheck Sweden AB, Nacka, Sweden.
    Claesson, Johan
    Department of Building and Environmental Technology, Division of Building Physics, Lund University, Lund, Sweden.
    Hofmeister, Morten
    Research Center for Built Environment, Energy, Water and Climate, VIA University College, Horsens, Denmark.
    Janson, Ulla
    Department of Building and Environmental Technology, Division of Building Services, Lund University, Lund, Sweden.
    Jensen, Aksel Wedel Bang
    Region Midtjylland, Aarhus, Denmark; Department of Planning, Aalborg University, Aalborg, Denmark.
    Termén, Jens
    Energy Machines, Gävle, Sweden.
    Javed, Saqib
    Department of Building and Environmental Technology, Division of Building Services, Lund University, Lund, Sweden.
    How to develop fifth-generation district heating and cooling in Sweden?: Application review and best practices proposed by middle agents2023In: Energy Reports, E-ISSN 2352-4847, Vol. 9, p. 4971-4983Article in journal (Refereed)
    Abstract [en]

    Sweden has an ambitious plan to fully decarbonise district heating by 2030 and to contribute with negative emissions of greenhouse gases in 2050. The vagaries of the energy market associated with climate, political, and social changes entail cross-sectoral integration that can fulfill these national targets. Fifth-generation district heating and cooling (5GDHC) is a relatively new concept of district energy systems that features a simultaneous supply of heating and cooling using power-to-heat technologies. This paper presents best practices for developing 5GDHC systems in Sweden to reach a consensus view on these systems among all stakeholders. A mixed-method combining best practice and roadmapping workshops has been used to disseminate mixed knowledge and experience from middle agents representing industry professionals and practitioners. Four successful implementations of 5GDHC systems are demonstrated and the important learned lessons are shared. The best practices are outlined for system planning, system modeling and simulation, prevailing business models for energy communities, and system monitoring. A roadmap from the middle agents’ point of view is composed and can be utilised to establish industry standards and common regulatory frameworks.

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  • 3.
    Adolfsson, Sebastian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Expanding operation ranges using active flow control in Francis turbines2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report contains an investigation of fluid injection techniques used in the purpose of reducing deleterious flow effects occurring in the draft tube of Francis turbines when operating outside nominal load. There is a focus on implement ability at Jämtkrafts hydroelectric power plants and two power plants were investigated, located in series with each other named Lövhöjden and Ålviken. The only profitable scenario found with some degree of certainty was an increase in the operating range upwards to allow overload operation.

    Findings show that both air and water can be introduced in various locations to improve hydraulic efficiency around the turbine parts as well as reduce pressure pulsations in harmful operating regions. Investments in such systems have proven useful and profitable at several facilities with poorly adapted operating conditions. But due to losses in efficiency when operating injection systems, it turns out unprofitable in situations where it does not improve the operating range in a way that is resulting in increased annual or peak production.

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    Lastområdesutvidgning med aktiv flödeskontroll i Francisturbiner
  • 4.
    Ahenkan, Albert
    et al.
    Department of Public Administration and Health Services Management, University of Ghana Business School, Ghana.
    Cudjoe, Mawuena A.
    Department of Accounting, University of Ghana Business School, Ghana.
    Karimu, Amin
    Umeå University, Faculty of Social Sciences, Centre for Environmental and Resource Economics (CERE). Environmental Policy Research Unit (EPRU), University of Cape Town, South Africa.
    Abekah-Nkrumah, Gordon
    Department of Public Administration and Health Services Management, University of Ghana Business School, Ghana.
    Environmental and sustainability management in the oil and gas industry2023In: Sustainability management in the oil and gas industry: emerging and developing country perspectives / [ed] Joshua Yindenaba Abor; Amin Karimu, Routledge, 2023, p. 223-239Chapter in book (Refereed)
    Abstract [en]

    Sustainability management in the oil and gas industry in emerging and developing countries has become essential to the sustainable development discourse because of the growing interest regarding the compatibility of the industry to a sustainable future. This chapter examines the management of environmental and sustainability issues in oil and gas industry in developing countries. The chapter comprises five sections. The first section presents the introduction and overview of the oil and gas industry in Africa. The second section presents sustainability challenges of the industry. The third section discusses environmental governance, ethics, and management of environmental impacts. The fourth section discusses how environmental impacts of the oil and gas industry are being managed and the regulatory framework for pollution prevention. The fifth section highlights corporate environmentalism in industry, the efforts to reduce pollution, and the greening of the sector. The chapter reveals that although the oil and gas sector has improved the economies of most developing countries over the years, the oil and gas sector activities have had significant environmental impacts. The chapter notes that several pressures from regulators and individuals force firms to behave ethically. What has helped mitigate the effect of the activities of the industry is the sense of duty towards the environment.

  • 5.
    Allard, Ingrid
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Achieving building energy performance: requirements and evaluation methods for residential buildings in Sweden, Norway, and Finland2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Building energy performance has always been important in the cold climate of Sweden, Norway and Finland. To meet the goal that all new buildings should be nearly zero-energy buildings by 2020, set in the EU directive 2010/31/EU [1] on the energy performance of buildings (EPBD recast), the building sector in Europe now faces a transition towards buildings with improved energy performance. In such a transition, a discussion is needed about the objective of the improvement – why, or to what end, the building energy performance should be improved. The objective of improving building energy performance is often a political decision, but scientific research can contribute with knowledge on how the objectives can be achieved.

    This thesis addresses how the indicators used in the requirements used to achieve building energy performance in Sweden, Norway, and Finland, and the methods used to evaluate these requirements, reflect building energy performance. It also addresses difficulties in achieving comparable and verifiable indicators in evaluations of building energy performance. The research objective has two parts: to review, compare, and discuss (i) requirements and (ii) evaluation methods used to achieve energy performance of residential buildings in Sweden, Norway and Finland. The work in this thesis includes reviews of the requirements used in national building codes and passive house criteria to achieve building energy performance, of methods used to evaluate compliance with such requirements, and of methods used specifically to evaluate the indicator Envelope Air Tightness.

    The results show that different sets of indicators are used to achieve building energy performance in the studied building codes and passive house criteria. The methods used to evaluate compliance with requirements used to achieve building energy performance are also different, but calculation methods are generally more often used than measurement methods. The calculation- and measurement methods used are often simple. A methodology to analyze the deviation between predictions- and measurements of building energy performance (the performance gap) was developed, to investigate the effects of different evaluation methods on different indicators used to achieve building energy performance. The methodology was tested in a case-study. This study indicated that the choice of method affects which parts of the performance gap reflected in the indicators Supplied Energy (see Terminology), Net Energy (see Terminology), and Overall U-value. Among the reviewed methods to evaluate air tightness, the Fan/Blower Door Pressurization is well known and preferred by professionals in the field. The results in this thesis may be useful when choosing indicators and evaluation methods to achieve different objectives of improving building energy performance and in the quest towards comparable and verifiable indicators used to achieve building energy performance.

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  • 6.
    Allard, Ingrid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy performance criteria for residential buildings: A comparison of Finnish, Norwegian, Swedish, and Russian building codes2021In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 250, article id 111276Article in journal (Refereed)
    Abstract [en]

    Building code are considered to be an effective policy tool to reduce energy use in buildings. In practice, national priorities influence the indicators and criteria adopted in the building codes. Consequently, neighbouring countries with similar climate conditions may use different criteria in their building codes to regulate the energy performance. In this paper, the energy performance criteria and their relative stringency in the latest residential building codes of Finland, Norway, Sweden and Russia are compared. The study is based on energy performance evaluations of one single-family building and one multi-family building, located in the north of Sweden. Both buildings complied with the Norwegian and Russian building code. However, the buildings did not comply with the specific fan power and heat loss criteria in the Finnish building code. Additionally, the single-family building did not comply with the specific primary energy and electric powerdemand criteria in the Swedish building code when heated by an electric heater. The national standard input data were found to have a large influence on the buildings’ compliance with the studied energy use criteria. Policy implications of the results are discussed.

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  • 7.
    Allard, Ingrid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hassan, Osama
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Methods for air tightness analysis for residential buildings in Nordic countries2012In: Methods for air tightness analysis forresidential buildings in Nordic countries, Southampton: WIT Press, 2012, p. 311-322Conference paper (Refereed)
    Abstract [en]

    Envelope air tightness is one factor that has impact on the energy performance ofbuildings. The goals of the directive 2010/31/EU, on energy performance ofbuildings, raise the importance of building energy performance analysis in theprocess. Measurements of air tightness can be useful both when evaluatingbuilding energy performance and developing new building techniques. The aimof this paper is to review and evaluate methods to measure air tightness in bothnew and existing residential buildings in Sweden, Norway and Finland, based onan international literature study and a survey. The methods are categorized basedon a number of criteria to determine their suitability in different situations.Advantages and disadvantages of the methods are discussed, as well ascommonly used methods in the three countries. The review shows that thestandard ISO 9972 is used for verification in all three countries, but alternativesexist that might be more suitable in certain situations. Simpler methods are usedin the building process to increase air tightness. To achieve a comparablemeasurement, both common methods and commonly defined units are needed.

  • 8.
    Allard, Ingrid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hassan, Osama A. B.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Methods for energy analysis of residential buildings in Nordic countries2013In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 22, p. 306-318Article, review/survey (Refereed)
    Abstract [en]

    To meet the goals of the directive 2010/31/EU on the energy performance of buildings, the building sector in Europe now faces a transition towards more energy efficient buildings. Research and development of new energy solutions and technology will be necessary for the transition and the importance of analyzing building energy performance increases. This paper aims to review and evaluate different methods that are commonly used to analyze energy performance in residential buildings in Nordic countries, primarily in Sweden, Norway and Finland. A short international review of regulations is also included. The goal is to find commonly used methods and possibilities for the future. The introduced methods are summarized, categorized and compared based on their advantages and disadvantages. Although the three Nordic countries have similar climate conditions and building traditions, the review shows relatively large variations in the definitions of energy performance for residential buildings, as well as variations in how measurements and calculations are used in the methods for energy performance analysis. In the conducted review, methods, or parts of methods, are also found to be used. The methods used to analyze energy performance are found to be more similar than the concepts of energy performance itself in the three countries. These aspects may be considered in further work to develop an international policy practice for energy performance of residential buildings in cold climate.

  • 9.
    Allard, Ingrid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energy performance indicators in the Swedish building procurement process2017In: Sustainability, E-ISSN 2071-1050, Vol. 9, no 10, article id 1877Article in journal (Refereed)
    Abstract [en]

    In Sweden, all new buildings need to comply with the National Board of Housing, Building and Planning’s requirement on specific purchased energy (kWh/m2). Accordingly, this indicator is often used to set design criteria in the building procurement process. However, when energy use is measured in finished buildings, the measurements often deviate significantly from the design calculations. The measured specific purchased energy does not necessarily reflect the responsibility of the building contractor, as it is influenced by the building operation, user behavior and climate. Therefore, Swedish building practitioners may prefer other indicators for setting design criteria in the building procurement process. The aim of this study was twofold: (i) to understand the Swedish building practitioners’ perspectives and opinions on seven building energy performance indicators (envelope air leakage, U-values for different building parts, average U-value, specific heat loss, heat loss coefficient, specific net energy, and specific purchased energy); and (ii) to understand the consequences for the energy performance of multi-family buildings of using the studied indicators to set criteria in the procurement process. The study involved a Delphi approach and simulations of a multi-family case study building. The studied indicators were discussed in terms of how they may meet the needs of the building practitioners when used to set building energy performance criteria in the procurement process.

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  • 10.
    Allard Stolterman, Ingrid
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Regulating energy performance of residential buildings in cold climate: a study of indicators, criteria, and evaluation methods2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Building energy performance has been important in Fennoscandia ever since the early vernacular houses, to combat the cold climate. Due to EU directive 2010/31/EU on the energy performance of buildings (EPBD recast), building energy performance has become even more relevant in northern Europe the last decade. Objectives for improving building energy performance may include reducing cost and CO2-emissions, increasing energy independency, and improving the indoor climate. Different indicators, criteria, and evaluations methods may be used to reach these objectives. This dissertation addresses indicators, criteria, and evaluation methods used to regulate energy performance of residential buildings in Sweden, Norway, Finland, and Russia. Four research objectives are covered: (RO1) comparing criteria and evaluation methods used to regulate energy performance of residential buildings in Sweden, Norway, and Finland, (RO2) studying the perspective of professionals with experience in building energy performance evaluation on (a) methods for evaluating envelope air leakage of residential buildings in Sweden and Finland and (b) potential energy performance indicators in the Swedish procurement process of multi-family buildings, (RO3) developing an approach for analysing the performance gap between design predictions and measurements that can be used to verify compliance with requirements on building energy use in practice, and (RO4) comparing the stringency of the energy performance criteria for residential buildings between the Swedish, Norwegian, Finnish, and Russian national building code. Many differences were found between how energy performance of residential buildings was regulated in the four countries. In Sweden, measurements were used more for evaluating building energy performance than in the other countries. As of 1st January 2020, the Finnish building code was characterized by its focus on the building heat loss and stringent energy performance criteria compared to the other countries. The Norwegian building code was characterized by a relatively narrow system perspective on energy performance, with no regulation of the energy production efficiency or energy source. The Russian building code also had a narrow system perspective but was also characterized by its focus on the form factor – the relationship between building volume and enclosing area. The practitioners wanted to minimize the influence from building operation and user behaviour on energy performance evaluations in the Swedish building procurement process of multi-family buildings. Hence, they preferred component-focused indicators or indicators with a narrow system boundary. An approach has been developed for analyzing the performance gap between design phase predictions and measurements. The approach can be used to verify the finished building’s energy performance, with minimal influence from occupant behavior and building operation.

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  • 11.
    Almgren, Mattias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effekten av dagsljus- och närvarostyrd LED-belysning i en befintlig kontorsbyggnad ur energi-, ekonomi- och ljusmiljösynpunkt2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    An important measure to reduce buildings’ environmental impact is to make the artificial lighting more effective, which is the biggest electricity consumer of Swedish office buildings and accounts for more than 30 % of the total electricity consumption.A case study has been carried out in this master thesis as a part in an existing project with ÅF Lighting, where new strategic avenues has been explored in which to combine day- and electrical light in office landscapes in a smarter, more energy-efficient manner and at the same time improve the lighting environment.Two office spaces at the own head office of ÅF in Solna, Stockholm has been used in the case study, where two different LED lighting solutions got installed. One with pendant luminaries, desk lamps and downlights, and one with only recessed luminaires.Through several computer simulations, electricity and light measurements, questionnaires, interviews etc., it has been investigated how the heat and cooling load, electricity consumption, lighting quality and operating costs has been affected of the change of the lighting system. The lighting environment, daylight conditions, heat and cooling load, economical savings and electricity consumption for the two offices has been investigated in diaLUX, DIVA-for-Rhino, IDA ICE 4.7, ecoCALC and Mitec Monitor, respectively. The electricity measurements showed that the lighting solutions’ electricity consumption got reduced with 71,6 % on floor 5 and 68,1 % on floor 10 with the new LED lighting solutions and control systems during the investigated month.Through the IDA ICE energy simulations over a year it was shown that the total yearly cooling load to floor 5 and floor 10 got reduced with 19 % and 17 %, which can be explained by the lesser heat gain from the more energy efficient lighting and the controlling of this. Though a small increase in heating load, the total energy consumption got reduced with around 12-14 % on both floors. The simulations also showed that the total electricity consumption of the lighting got reduced with 70 % for floor 5 and 63 % for floor 10 after the change to the new LED lighting solutions and implementation of control systems.The LCC for the new lighting solutions showed that these have a higher investment cost than the total operation cost for the existing solution over the life cycle. However, the costs to run the LED solutions are less than a third of the operation costs for the existing solution, and after the exchange the carbon dioxide emissions can be reduced with close to 70 %.Through this case study it has been shown that the energy consumption from lighting can be highly reduced with the installation of energy efficient lighting in combination with smart control systems, and it can also have a positive effect on the lighting environment. However, the high investment costs of the LED solutions lead to the conclusion that installation of these solutions today is not economically justifiable.

  • 12.
    Almstedt, Kalle
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektiviseringsåtgärder på Gustavsvik resorts AB2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Badhus är den typ av svenska lokaler som använder mest energi, ofta med en energiprestanda som är långt högre än BBRs gränsvärden för ny- och ombyggnationer. Denna rapport är resultatet av ett examensarbete för Civilingenjörsprogrammet i energiteknik vid Umeå Universitet. Det har utförts på uppdrag av teknikkonsultföretaget KAMTechnology AB åt upplevelseanläggningen Gustavsvik resorts AB. Gustavsvik ligger i Örebro och består av bland annat äventyrsbad, motionsbad, gym, camping med mera. Detta examensarbete syftar till att utreda möjligheter och ta fram förslag till energieffektiviseringsåtgärder för Gustavsviks badanläggning. Studien har avgränsats till att behandla energisystemet för kyla och värme med fokus på kylkretsen och värmeåtervinning ur gråvatten.

    Potentialen för värmeåtervinningen ur Gustavsviks gråvatten har beräknats till cirka 130 000 kWh/år, vilket utgör ca 20 % av deras köpta energi för varmvattenberedning. Det finns en handfull produkter på marknaden för värmeåtervinning ur grå- och avloppsvatten, som hävdar god prestanda och lönsamma installationer. Det kan konstateras att det finns få utförda studier och genomförda projekt som presenterar mätvärden och prestanda för dessa typer av installationer. Intresset för dessa typer av anläggningar tycks ändå öka och branschorganisationer försöker skynda på utvecklingen genom bland annat tekniktävlingar vilket sammanfattas i, och styrks, av litteraturstudien som utgör en del av denna rapport.

    Platsbesök har utförts för att samla in data från anläggningens styr- och övervakningssystem. Insamlad data har loggats under 2013 och utgörs av temperaturer, flöden samt el- och fjärrvärmeanvändning. Kompletterande mätningar av kyl- och värmebärarens flöde utfördes även för att kunna uppskatta värmepumparnas kyl- och värmeproduktion En begränsad kartläggning av Gustavsviks kylkrets har utförts, där även anläggningens två värmepumpar har utvärderats. Värmepumparnas prestanda visade sig vara sämre än vad tillverkarna uppger och det finns därmed en möjlig besparingspotential i att förbättra och optimera deras drift. Datahanteringen och beräkningar har främst gjort i Microsoft Excel. Under examensarbetet har det identifierats flera fall där man kyler och värmer på samma ställe, vilket betraktas som möjligheter till energieffektiviseringsåtgärder. Slutsatserna av denna studie är att Gustavsvik har stora möjligheter till att sänka sin energiförbrukning. Detta genom att bland annat installera värmeåtervinning ur gråvatten, bygga bort konkurrerande värme och kyla samt att justera in sitt energisystem. Det som Gustavsvik rekommenderas att göra i första hand är en heltäckande energikartläggning av sitt energisystem. 

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    Energieffektiviseringsåtgärder på Gustavsvik resorts AB
  • 13.
    Amjadi, Golnaz
    et al.
    Umeå University, Faculty of Social Sciences, Centre for Environmental and Resource Economics (CERE). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Business Administration. STATEC Research, STATEC (National Institute of Statistics and Economic Studies), Luxembourg, Luxembourg.
    Lundgren, Tommy
    Umeå University, Faculty of Social Sciences, Centre for Environmental and Resource Economics (CERE). Department of Forest Economic, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Zhou, Wenchao
    Umeå University, Faculty of Social Sciences, Centre for Environmental and Resource Economics (CERE).
    A dynamic analysis of industrial energy efficiency and the rebound effect: implications for carbon emissions and sustainability2022In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 15, no 7, article id 54Article in journal (Refereed)
    Abstract [en]

    Energy efficiency improvement (EEI) is generally known to be a cost-effective measure for meeting energy, climate, and sustainable growth targets. Unfortunately, behavioral responses to such improvements (called energy rebound effects) may reduce the expected savings in energy and emissions from EEI. Hence, the size of this effect should be considered to help design efficient energy and climate targets. Currently, there are significant differences in approaches for measuring the rebound effect. Here, we used a two-step procedure to measure both short- and long-term energy rebound effects in the Swedish manufacturing industry. In the first step, we used data envelopment analysis (DEA) to measure energy efficiency. In the second step, we use the efficiency scores and estimated a derived energy demand equation including rebound effects using a dynamic panel regression model. This approach was applied to a firm-level panel dataset covering 14 sectors in Swedish manufacturing over the period 1997–2008. We showed that, in the short run, partial and statistically significant rebound effects exist within all manufacturing sectors, meaning that the rebound effect decreased the energy and emission savings expected from EEI. The long-term rebound effect was in general smaller than the short-term effect, implying that within each sector, energy and emission savings due to EEI are larger in the long run compared to the short run. Using our estimates of energy efficiency and rebound effect, we further performed a post-estimation analysis to provide a guide to policy makers by identifying sectors where EEI have the most potential to promote sustainable economic growth with the lowest environmental impact.

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  • 14. Anderssen, C.
    et al.
    Lindgren, R.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Carvalho, R.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Malmborg, V.
    Ahlberg, E.
    García-López, N.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Eriksson, A.
    Kristensen, T.B.
    Svenningsson, B.
    Boman, C.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pagels, J.
    SOA Formation and Particle Characteristics in the Emissions from Biomass Cook Stoves Used in the Developing Countries2017In: SOA Formation and Particle Characteristics in the Emissions from Biomass Cook Stoves Used in the Developing Countries, 2017Conference paper (Other academic)
  • 15.
    Andersson, Emil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Online Metallurgical Mass Balance and Reconciliation2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In mineral processing, one of the most important and versatile separation methods is flotation. Flotation utilizes the different surface properties of the valuable minerals in the ore to separate them from the less valuable gangue material in the ore. Crushed and ground ore is mixed with water and fed into flotation tanks. In the flotation tanks, the particles of valuable mineral are made hydrophobic. That way, they can be floated by attaching to air bubbles and gather on top of the flotation tank as froth. This froth, containing higher concentrations of valuable mineral, is recovered and then processed further.

    The flotation circuit is controlled and maintained using measurements on the mass flows and grades of different materials. Due to economical, practical, and technological limitations, these measurements are performed at a chosen number of points in the circuit and at discrete points in time. Poor measurement data can have devastating consequences if the operators are left with limited information and errors in the circuit remain undetected.

    The accuracy of the acquired measurements is improved by performing mass balance and reconciliation. Traditionally, mass balance uses the sum of the total mass flows and the average grades over long times to avoid including the internal mass of the circuit in the calculations. It is desirable to perform mass balance directly to allow for faster intervention if any failures occur in the circuit during the on-line process.

    This report describes an on-line dynamic approach towards mass balancing and reconciliation of the mass flows and grades in a flotation circuit. Here, physical models of the flotation circuit are used to construct mass balance constraints using interpolation and test functions and the mass balance problem is posed as an optimization problem. The optimization problem is to adjust the assay such that the residual, the difference between the measured and the adjusted assay, is minimized while maintaining mass balance.

    An implementation in MATLAB and tests on synthetic data show that the dynamic formulation of mass balance does adjust 'erroneous' measurements such that mass balance is fulfilled. Given this result, there are still important aspects of the implementation that have to be addressed. The model uses the unknown and cell specific parameters flotation rate and recovery. Thus, these must be found or properly modeled. This report proposes a possible model for flotation rate as well as a strategy to find the recovery. The requirements of accuracy and speed of the implementation are also discussed.

    Possible next steps of this project is to further confirm a time effective implementation using synthetic data. Consequently, the implementation can be adapted for natural data in order to verify correctness of models.

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  • 16.
    Andersson, Erik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvärdering av möjligheten att tillvarata energi ur processvatten: En undersökning gjort vid Olofsfors AB på uppdrag av UMIA AB.2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The company Olofsfors AB manufactures drive belts for forest machinery, known as ECO-Tracks, and abrasion-resistant steel and cutting edges for graders, excavators and tractors, known as Bruxite and SharqEdges. Manufacturing these products requires the steel to be heated and molded, then submerged in water and hardened. The water used in the hardening of steel is pumped to the process from pits below the floor and then pumped back to the pit after it’s been used. Since the temperature of this water rises after being used to harden the steel the temperature of the pumping pit needs to be adjusted to maintain its setpoint of 21°C. This is done by disposal of hot water from the pit to the river outside while new, cold water, from the river is pumped into the pit. The hot water that is being disposed of contains energy that has not at all been utilized, this has led to the purpose of this report which is to examine the possibility to utilize parts of the energy in the water.

     

    Two possible outlets for the energy at the plant has been selected as especially interesting: • Heating of ventilation supply air in two units with low thermal efficiency and relatively high airflows where the supply air temperature is to be increased from 9 °C to 15 °C. • Fan heaters installed with electric batteries of approximately 200 kW capacity, which heats the premises and serves as an air barrier at the intake ports for metal.

     

    Calculations of power available in one of the factory pump pits during the heating season from October to May and the power required for deposition areas were made. The result obtained is illustrated by means of duration charts from which required and available energy is deduced.

     

    The result of this:

    Pump pit                             887 MWh / October to May

    Ventilation                          642 MWh / year

    Fan heaters                         515 MWh / year

     

    A draft measure has been developed in which two heat pumps delivers hot water for heating of both the ventilation supply air and liquid batteries in air fan heaters. This measure proposal means a cost saving of approximately 390 000 SEK / year where pay-off time of the investment is approximately 5 years.

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  • 17.
    Arbid, Yara
    et al.
    Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, France.
    Usman, Muhammad
    Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, France.
    Luong, N. Tan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Physics, Chalmers University of Technology, Göteborg, Sweden.
    Mathon, Baptiste
    Treewater, Lyon, France.
    Cedat, Bruno
    Treewater, Lyon, France.
    Boily, Jean-Francois
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hanna, Khalil
    Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, France; Department of Chemistry, Durham University, Durham, United Kingdom.
    Use of iron-bearing waste materials in laundry wastewater treatment2024In: Journal of Water Process Engineering, E-ISSN 2214-7144, Vol. 57, article id 104717Article in journal (Refereed)
    Abstract [en]

    This study evaluates the efficiency of a steel waste-derived magnetite (WM) for the treatment of laundry wastewater under various irradiation conditions (ultraviolet-A and C: UVA and UVC), both in the presence and absence of H2O2. Because WM can contain magnetite and elemental iron phases, its ability to remove ciprofloxacin and phenol, here used as model pollutants, and total organic carbon (TOC) from laundry wastewater was compared with that of synthetic magnetite (SM) and zero-valent iron (ZVI). We show that the mixed ZVI/H2O2 system under UVC degraded up to 80 % of the pollutant and 70 % of the TOC. WM had, on the other hand, a lower reactivity for pollutants due to the presence of inorganic impurities, yet removed up to 60 % of TOC. In all cases considered in this work, a higher degradation rate was observed under UVC irradiation than under UVA. Moreover, iron-based materials can adsorb heavy metals co-existing in the laundry wastewater. Recyclability tests showed no significant loss in the activity of WM or SM for up to 5 cycles in laundry wastewater. This study can have strong implications for the development of new remediation technologies relying on industrial solid wastes, especially in the context of a circular economy.

  • 18.
    Arnoldsson, Kristina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Patrik L
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Formation of environmentally relevant brominated dioxins from 2,4,6,-tribromophenol via bromoperoxidase-catalyzed dimerization2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 13, p. 7239-7244Article in journal (Refereed)
    Abstract [en]

    Polybrominated dibenzo-p-dioxins (PBDD) are emerging environmental pollutants with structural similarities to the highly characterized toxicants polychlorinated dibenzo-p-dioxins. The geographical and temporal variations of PBDD in biota samples from the Baltic Sea do not display features that are normally related to anthropogenic sources such as incineration, and therefore the natural formation of PBDDs has been suggested. This study of the bromoperoxidase mediated oxidative coupling of 2,4,6-tribromophenol (an abundant substance that is naturally formed in marine systems) identified the formation of ppb-level yields of 1,3,6,8-tetrabromodibenzo-p-dioxin (1,3,6,8-TeBDD) through direct condensation. Additional TeBDDs (1,3,7,9-TeBDD, 1,2,4,7-TeBDD and/or 1,2,4,8-TeBDD) and tri-BDDs (1,3,7-TrBDD and 1,3,8-TrBDD) were frequently formed, but at lower yields. The formation of these TeBDDs probably proceeds via bromine shifts or Smiles rearrangements, while the TrBDDs may result from subsequent debromination processes. Since all of the congeners formed by oxidative coupling and subsequent reactions are also found in Baltic Sea biota, the results support the theory that PBDDs are formed from natural precursors.

  • 19. Asthana, Arvind
    et al.
    Nair, Gireesh
    ?.
    Big efficiency in small scale2001Other (Other (popular science, discussion, etc.))
  • 20.
    Auland, Clara
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Storskaligt logistiksystem för vätgastransport2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The energy transition is crucial to limit the global carbon dioxide emissions. Renewable energy sources like wind and solar are intermittent and we need to find ways to use the electricity surplus and store energy. Hydrogen is an energy carrier and has the potential to be a key to achieve a renewable energy system. The aim of the study is to investigate the feasibility for an economic and technical sustainable system for hydrogen distribution. The goal was to calculate transmission cost for different types of hydrogen transport. A profound literature study and external analysis was made in the beginning. Then two cases were selected in the northern part of Sweden. Based on the conditions, transport through pipeline, road transport and transport by rail were choosen.

    The results for transport by road suggests that very frequent transports are required to deliver the quantity in the cases taken up, which results in high costs. Distribution cost by rail implies high investment costs and there are no significant difference between distribution cost for the cases. Furthermore the results implies that pipeline has low operating costs for both cases and it also implies a difference between investments cost for the cases. The result also indicates that transmission cost by pipelines is cheaper than transmission cost for electricity.

    Which one is the best option depends on many different factors such as conditions at the location, electricity price, distance and the volume. There are uncertainties in the results for transport by road and by rail, which makes it difficult to conclude based on the current findings. The comparision between hydrogen and electricity should be seen as a rough estimate due to the uncertanties.

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  • 21.
    Axelsson, Sebastian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning av en potentiell installation av FTX-ventilation med värmeåtervinning2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main purpose of this degree project is to study and investigate a specific existing building to contribute to promoting a sustainable future on a larger scale. At the same time, shows that in many cases it can also be profitable to invest in a new energy-efficient system. After studying the structure and existing system of the building, it was found that a new ventilation system would be relevant.

    The building holds 83 apartments on a total area of 5 474 m2 and is located in northern part of Sweden, where temperatures of -30 °C are commen during winter time. The property is currently run by an exhaust air system for transporting consumed air, fresh air flows through outside valves directly into the recidence. Because the property is located in a place where cold outdoor temperatures occur many times a year, it's unlikely to transport cold air directly into the dwelling without preheating. This means that the current district heating consumption of the radiators will achieve unacceptable high values to maintain a good indoor envirement.

    The project that has been implemented shows that there are primarily an opportunity to install an FTX system in the homes. In many cases, there are a lack of space that contradicts an installation. Apart from the space, the result shows that district heating can be reduced by up to 600 MWh per year. This would mean a saving of 411 KSEK per year for the entire property. The cost of the required material is estimated at approximately 3.1 MSEK. This means that the investment is repaid after about 7-8 years. The figures mentioned above correspond to the material package that is reported in the report's results and assumes that existing air ducts present in the accommodation today remain but expanded. The design of the proposal presented is based on a balanced ventilation with heat recovery (80 %) with separate units for each apartement.

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    Master Thesis
  • 22.
    Azizi, Shoaib
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A multi-method assessment to support energy efficiency decisions in existing residential and academic buildings2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Rapid decarbonization of building stock is essential for the energy transition required to mitigate climate change and limit the global temperature rise below 1.5 °C. The decision-making for the adoption of energy efficiency measures (EEMs) is often complex and involves lasting consequences and risks. The strategy to direct and support the decision makers can significantly increase the adoption rate of EEMs in buildings. This Ph.D. project focuses on facilitating sustainability improvement in buildings by supporting the decision makers who are accountable for the consequences of adopting the EEMs. Energy efficiency improvement is decided and managed differently in various types of buildings and contexts and encounters different challenges and opportunities. Accordingly, it is required to understand the needs to select adequate strategies and to devise effective supporting interventions for energy efficiency improvement.

    The owners of single-family houses are often the occupants who are in charge of the most decisions to improve energy efficiency in their dwellings. The situation is rather different in multi-family buildings and academic buildings in which organizational management adds more complexity and the decisions affect various stakeholders. The studies in this project are based on qualitative and quantitative data collected from single-family houses, multi-family buildings, and university buildings in northern Sweden. Surveys were used to elicit the decision makers' perceptions of different types of buildings. Moreover, sensor data from university buildings were used in the case studies to develop informative metrics for space use efficiency and to analyze the effect of sensor positioning on monitored data.

    The initial work involved understanding the opportunities and challenges of improving energy efficiency in buildings and the tradeoffs between the perceived benefits and barriers. This part of the thesis provided the foundation and inspiration for the rest of the project, including investigating how to bundle several measures and use information and communication technologies (ICT) for building sustainability. The findings show lack of information and evidence that could justify the beneficial outcomes of EEMs is a major barrier for effective decision-making. Clear information on potential improvements allows sharing the responsibilities among different stakeholders and increases the management capacity to handle projects and adopt EEMs. Using feedback tools (for example, space use and/or energy use visualizations) might be an effective strategy to influence decision makers.

    Various studies incorporated in this multidisciplinary Ph.D. thesis develop and investigate strategies to support decision makers to improve energy efficiency in buildings. The findings provide insights to policymakers and businesses to devise intervention strategies for energy efficiency in buildings.

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    PhD Dissertation_Shoaib Azizi
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    Posting sheet
  • 23.
    Azizi, Shoaib
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Adoption of Energy Efficiency Measures in Renovation of Single-Family Houses: A Comparative Approach2020In: Energies, E-ISSN 1996-1073, Vol. 13, no 22, article id 6042Article in journal (Refereed)
    Abstract [en]

    Inclusion of energy efficiency measures (EEMs) in the renovation of the single-family housing stock can unlock the potential for much-needed energy efficiency to tackle climate change. Energy renovation (ER) in single-family houses is often promoted as an aggregate process, and EEMs are treated homogenously without sufficient attention to their differences. This study applies a comparative analysis on common EEMs using chi-square test to investigate the influence of factors already found affecting the implementation of ER. This paper addresses the “personal” and “house-related” factors influencing the adoption of EEMs regardless of motives or barriers leading the adopters’ decisions. This strategy is useful to highlight the contexts leading to an increase in the adoption rate of different EEMs. The analysis is based on a questionnaire survey mailed in spring 2017 to 1550 single-family homeowners in the northern region of Sweden. Approximately 60% of respondents showed interest in adopting at least one EEM if they implement a major renovation. About 46% of respondents stated to have at least one indoor environmental problem (IEP) in their houses, and IEPs are found to have significant relations with homeowners’ interest to adopt several different EEMs. The policy implications related to different EEMs are discussed.

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  • 24.
    Azizi, Shoaib
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analysing the house-owners’ perceptions on benefits and barriers of energy renovation in Swedish single-family houses2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 198, p. 187-196Article in journal (Refereed)
    Abstract [en]

    Single-family houses offer a large potential for energy savings by energy renovation (ER). Homeowners’ motivation to implement ER derives from the benefits and barriers they perceive. Benefits are the positive consequences that can motivate homeowners to act and barriers are the challenges that demotivate them to undertake ER. Different benefits and barriers do not homogenously affect every homeowner. Identifying motivating benefits and demotivating barriers for each specific group among homeowners can shed lights on ER decision-making and enable policies that are more effective. The objective of this study is to contextualize the implementation of ER by understanding how the perceived benefits and barriers influence homeowners. This study links the expected consequences, which are benefits and barriers to the influential factors on ER, which are used to group the homeowners.

    The analysis is based on a questionnaire survey mailed to 1550 owners of single-family houses in northern Sweden. The perceptions of homeowners on benefits and barriers of ER are significantly different between the groups that are motivated and unmotivated to implement ER. Despite the perceived importance of some of the benefits such as energy cost reduction, they may not be determinative for the homeowners’ decision to undertake ER. The homeowners are more likely to implement ER for reasons other than energy use reduction such as for improving the indoor environment. The barriers such as the difficulty of finding a low-interest loan and reliable information sources are found to impede the intention to implement ER among different groups. Policy implications to facilitate ER in single-family houses are discussed.

  • 25.
    Azizi, Shoaib
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Demand-controlled energy systems in commercial and institutional buildings: a review of methods and potentials2019In: eceee 2019 Summer Study on energy efficiency:: Is efficient sufficient?, European Council for an Energy Efficient Economy (ECEEE), 2019, p. 1444-1450Conference paper (Refereed)
    Abstract [en]

    Heating, ventilation and air-conditioning (HVAC) are by farthe most energy intensive systems in commercial and institutionalbuildings with office spaces. This makes HVAC systemsattractive targets for energy efficiency improvement. New technologicaladvancements can play significant role on improvingenergy efficiency. Such advancements have been also emergedin form of novel management and control strategies, whichmight lead to considerable energy savings with relatively minorinvestments. This paper evaluates demand control HVAC andlighting to assess the energy saving potential of upgrading theconventional building energy systems.

    This paper provides a summary of different methods and occupancydetection technologies. A range of technologies andmethods are covered that vary in complexity, limitations andenergy saving potential. Additional benefits such as demandresponse are evaluated and other emerging applications arediscussed. Based on the review of methods and potentials, thepaper assesses the state of the art in demand controlled energysystems and suggests areas for further research.

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  • 26.
    Banerjee, Sourasekhar
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Ghosh, Soumitra
    Department of Computing Science and Engineering, Indian Institute of Technology, Patna, India.
    Mishra, Brojo Kishore
    GIET University, Gunupur, India.
    Application of deep learning for energy management in smart grid2022In: Deep learning in data analytics: recent techniques, practices and applications / [ed] Debi Prasanna Acharjya; Anirban Mitra; Noor Zaman, Springer, 2022, , p. 19p. 221-239Chapter in book (Refereed)
    Abstract [en]

    In the modern electronic power system, energy management and load forecasting are important tasks. Energy management systems are designed concerning monitoring and optimizing the energy requirement in smart systems. This research work is divided into two parts. The first part will contain load forecasting and energy management in a smart grid. Load forecasting in the smart grid can be divided into three parts long-term, mid-term, and short-term load forecasting. The second part will describe energy usage optimization for the electric vehicle. Here we will show grids to vehicle energy demand management and optimization. This chapter will first introduce different deep learning techniques and then discuss their applications related to smart-grid and smart vehicle.

  • 27.
    Berglund, Tomas
    et al.
    Algoryx Simulation AB.
    Mickelsson, Kjell-Ove
    LKAB.
    Servin, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics. Algoryx Simulation AB.
    Virtual commissioning of a mobile ore chute2018Conference paper (Other academic)
    Abstract [en]

    This paper describes the virtual commissioning of a mobile ore chute for sequential loading of trucks from a conveyor system with a continuous material flow. The design and control were tested in simulation environment and improved prior to its installation in an underground mine in full production. The altered design met the performance goal and the amount of rock spill and wear on surrounding equipment could be reduced significantly. The simulations were based on a novel combination of discrete element and multibody simulation using a nonsmooth dynamics formulation, integrated in a 3D modeling software. This enable both fast simulation, based on original CAD drawings, and high flexibility in modifying the design and control.

  • 28.
    Bheemasetti, Sravani
    et al.
    Civil and Environmental Engineering, South Dakota School of Mines and Technology, SD, Rapid City, United States.
    Upadhyayula, Venkata Krishna Kumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gadhamshetty, Venkataramana
    Civil and Environmental Engineering, South Dakota School of Mines and Technology, SD, Rapid City, United States; 2D-materials for Biofilm Engineering, Science and Technology (2D-BEST) Center, South Dakota School of Mines and Technology, SD, Rapid City, United States.
    Upcycling the solid wastes as precursors for graphene production2023In: Graphene Extraction from Waste: A Sustainable Synthesis Approach for Graphene and Its Derivatives / [ed] Chaudhery Mustansar Hussain, Ajeet Kumar Srivastav, Chandra Sekhar Tiwary, James M. Tour, Elsevier, 2023, p. 1-21Chapter in book (Refereed)
    Abstract [en]

    Owing to limited markets for recycled products, the United States annually discards~294 million tons of municipal solid waste (MSW) into landfills. These recycling rates for plastics and food wastes are as low as 7% and 3%, respectively. There is a need for stimulating innovative strategies for upcycling MSWs. This chapter discusses viable strategies for upcycling MSWs as precursors for graphene production using well-established nano-manufacturing techniques. We discuss the use of readily available MSW components as raw materials and the waste-to-energy infrastructure as a source of waste heat.

  • 29.
    Björnfot, Mikael
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    COMPUTATIONAL FLUID DYNAMICS MODELING FOR BENT SPILLWAY CHANNEL: Numerical validation of a small scale physical model2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Hydropower plants with spillways exposed to high pressures because of large discharges can result in a dam failure which ultimately results in devastating consequences. Therefore properly designed and constructed spillways are important. In this project there is an interest in examining the pressure distribution on a guided wall, measuring the water level inside the spillway and examine the water flow characteristics. The main purpose was to numerically model the flow behaviors at two upper pool levels +29.82 m and +30.92 m in order to achieve a comparison between a numerical model and a physical model.

    A previous experiment was carried out at Vattenfall R&D in Älvkarleby where a physical model was built. The main purpose of that study was to find an optimal form of a guide wall for free weir flow. This study served as guidelines for what should be investigated in this project.

    The methodology of the project began with a development of an initial CAD model created by Vattenfall R&D. The CFD model could be constructed into a volume model containing also an upstream reservoir. Next, a mesh that could numerically calculate the flow behavior was created in order to enable execution of the calculations. Furthermore, a big part of the method was to adjust the settings in Fluent so that the numerical model could recreate the flow behaviors of the physical model tests. The results indicate that the numerical model is an accurate replica of the physical model. The deviation comprising the mass flow rate came as close as 0.6 % from the physical model for the lower upper pool level. Highest calculated pressure was positioned at the bottom of the guided wall for both upper pool levels, which the results conducted from the physical model also indicated. Furthermore, results regarding the water level at the guided wall confirmed same statement Vattenfall's examinations pointed out, that the roof placed at the guided wall is needed in order to avoid major splashing.

    The present project has shown great results regarding the flow characteristics, pressure distribution, and the water level at the guided wall. Therefore, it is considered trustworthy enough to be used as a tool for Vattenfall R&D in future studies comprising the targeted spillway.

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  • 30.
    Borgenstam, Sebastian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Livscykelanalys och ekonomisk kalkyl av två KL-bjälklag2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    In building construction, there is a constant development in new materials and innovative technical solutions. The desire to reduce our carbon footprint is evident in the world and wood is a sustainable raw material. Forests is one of the big resources we have in Sweden. Cross-laminated timber (CLT) is a massive wood with high load-bearing capacity and stiffness has made it possible to build larger than ever before in wood. The question now is how to optimize the use of this environmentally friendly material. In this study, two different floor slabs with a supporting frame in cross-laminated timber were compared. To be able to compare CO2 consumption, Life Cycle Assessment was used and for the costs, economic calculations was built. The study covered part of the life cycle known as "cradle-to-gate".

    The thickness of the CLT slab was 230 mm. Apart from the slab, the beams differed both above and beneath the slab. One of the floor slabs was constructed with a subfloor system manufactured by Granab AB. The other floor slab was constructed with macadam and a thick layer of putty. That was the significant difference in the construction of the floor slab. There was also a differed connection between the walls and floor slabs. To achieve Boverket sound requirements, an elastic interlayer had to be placed along all the walls where it connects to the floor slab with subfloor system. For the joists with macadam, this was not necessary to achieve the sound requirements, which can easily be explained by the weight of macadam and putty.

    In the study, Östra Station Kvarter A in Umeå was used as a reference object. These buildings are to be built by Balticgruppen AB and during the study were still in the design stage.

    As a result of the comparison, the Macadam joists had a 22.9 percent lower economic cost than Granab, while the subfloor system-joists had a 9 percent lower environmental impact.

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  • 31.
    Boussaa, Youcef
    et al.
    Department of Built Environment and Energy Technology, Linnaeus University, Växjö, Sweden.
    Dodoo, Ambrose
    Department of Building Technology, Linnaeus University, Växjö, Sweden.
    Truong, Nguyen Le
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rupar-Gadd, Katarina
    Department of Built Environment and Energy Technology, Linnaeus University, Växjö, Sweden.
    Integrating passive energy efficient measures to the building envelope of a multi-apartment building in Sweden: analysis of final energy savings and cost effectiveness2023In: Buildings, E-ISSN 2075-5309, Vol. 13, no 10, article id 2654Article in journal (Refereed)
    Abstract [en]

    A major challenge in building energy renovation is to cost effectively achieve notable energy savings. This paper investigates cost-effective passive energy-efficiency measures for thermal envelope retrofit of a typical Swedish multi-apartment building from the 1970s. Here, the use of different types of insulation materials for the retrofits of roof, exterior walls, and ground floor are analyzed along with changing windows and doors with varying thermal transmittance values. The cost-effectiveness analysis is based on the net present value of the investment costs of the energy-efficiently measures and the achieved energy cost saving. Different economic scenarios and renovation cases are considered in techno-economic analyses to determine the cost-effective energy-efficiency retrofit measures. The results indicate that improved windows reduce energy demand for space heating by up to 23% and yield the highest final energy savings. However, additional mineral wool roof insulation is the most cost-effective measure under all economic scenarios. This measure gave the lowest ratio of cost effectiveness of about 0.1, which was obtained under the stable scenario. The final energy savings that can be achieved in a cost-effective manner vary between 28% and 61%, depending on the economic scenario and renovation case. This analysis emphasizes the influence of different renovation cases and economic parameters on the cost effectiveness of passive energy-efficiency measures.

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  • 32.
    Broberg, Thomas
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Economics. Umeå University, Faculty of Social Sciences, Centre for Environmental and Resource Economics (CERE).
    Egüez, Alejandro
    Umeå University, Faculty of Social Sciences, Centre for Environmental and Resource Economics (CERE). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Economics.
    Kazukauskas, Andrius
    Vilnius University.
    Effects of energy performance certificates on investment: A quasi-natural experiment approach2019In: Energy Economics, ISSN 0140-9883, E-ISSN 1873-6181, Vol. 84, article id 104480Article in journal (Refereed)
    Abstract [en]

    Incomplete information may be one reason why some households do not invest in energy efficiency even though it would benefit them to do so. Energy performance certificates (EPCs) have been promoted to overcome such information shortages. In this paper, we investigate whether EPCs together with mandatory home energy audits make households more likely to invest in energy efficiency. Our study takes advantage of the mandatory nature of the EPCs to avoid the potential selection bias problem that typically applies to studies using voluntary energy audits as the treatment. Our treatment group consists of single-household houses in Sweden sold from 2008, i.e., when EPCs became legally required in connection with sales of residential buildings, to 2015; while the control group consists of houses sold between 2002 and 2008, i.e., without an EPC. The results show that there is no statistically significant treatment effect for most of the measures that a household can take to improve the energy performance of their house. The significant treatment effect that we do find concerns a few heating system-related measures.

  • 33.
    Brunklaus, Birgit
    et al.
    RISE Research Institute of Sweden, Division of Built Environment, Department of System Transition and Service Innovation, Unit of Energy and Environmental Systems Analysis, Gothenburg, Sweden.
    Chiew, Yoon Lin
    RISE Research Institute of Sweden, Division of Materials and Production, Unit of Environment and Sustainable Chemistry, Mölndal, Sweden.
    Lundström, Anders
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Nilsson-Lindén, Hanna
    RISE Research Institute of Sweden, Division of Materials and Production, Unit of Environment and Sustainable Chemistry, Mölndal, Sweden.
    Saarikko, Ted
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    The connected, sustainable and inclusive society: IoT implementation in a Swedish municipality2022In: E3S Web of Conferences: 10th International Conference on Life Cycle Management (LCM 2021), EDP Sciences, 2022, Vol. 349, article id 11006Conference paper (Refereed)
    Abstract [en]

    The Internet of Things (IoT) is expected to transform the way we live, work, and learn. Using IoT could thus be a game-changer for municipalities towards sustainability. The Swedish municipality of Södertälje strives to develop IoT concepts and use open data for a sustainable and inclusive society. The goal of this study was to explore how IoT can enable route optimization and placement planning for increased operational efficiency. The goal was also to enhance the knowledge of the environmental and social benefits of IoT systems in the waste collection system in Södertälje. The analysis is based on Life Cycle Assessment (LCA) and interviews. The results show a minor climate change impact for the IoT solutions in the overall smart waste collection system. The major climate impact contributor was instead associated with the trash bags used. Additionally, the study showed that the performance of the system relies on smart planning of the operations and the transportations.

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  • 34. Buckland, Paul
    et al.
    Buckland, Philip I.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Prosser, Tim
    Edlington Wood: using Lidar to put ancient fields and old excavations into their contemporary landscape2020In: Transactions of the Hunter Archaeological Society, ISSN 0966-2251, Vol. 29, p. 84-101Article in journal (Refereed)
    Abstract [en]

    The Roman sites in Edlington Wood, three miles west-south-west of Doncaster, South Yorkshire, first came to wider notice as a result of finds by the woodman in the 1930s and the material was of sufficient interest for Philip Corder to use it as the basis for a paper in a festschrift to O. G. S. Crawford. Most of these finds and later material were deposited in Doncaster Museum, although others went to the owners and local metal detectorists. In 1970 a threat of quarrying led to a detailed survey of the site by the Royal Commission on Historical Monuments and limited excavation on one site. Two large areas within the Wood were cleared but remain as improved grassland. The recent availability of Lidar imagery allows the occupation sites and fragments of field system located by ground survey to be placed in a broader context of small rectangular fields and some attempt at a landscape chronology to be made. The cultivation of the fields in a system of cord rig is discussed.

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  • 35.
    Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Nyqvist, Roger
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Alexander, Benedict
    WSP, Sweden.
    Palsson, Gisli
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Eriksson, Samuel
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    The Swedish Transport Administration’s Toolbox and its Potential in Archaeological and Cultural Heritage Survey: Including a brief review of remote sensing, prospection and geodata analysis methods for archaeology and cultural heritage2018Report (Other academic)
    Abstract [en]

    This report provides an overview of the main remote sensing methods and geodata types used in archaeological prospection and cultural heritage survey. Based on a literature review, it provides an initial survey of the state of the art nationally and internationally, followed by details on the potential usage of different methods in a Swedish context. The details include pros and cons of methods as well as information on considerations that should be taken into account when applying the methods in different situations. Examples are provided where relevant to explain specific details or illustrate important points. Particular attention has been paid to laser scanning (LiDAR) data due to its increasing prevalence and prominence in landscape and archaeological surveys.

    The report continues with a preliminary evaluation of the possibilities for using data provided by Swedish Transport Administration (Trafikverket), obtained for other stages of the planning process, in archaeological and cultural heritage work. Specifically, the report looks at a number of geodata types obtained from The Geological Survey of Sweden (Sveriges geologiska undersökning/SGU), a nature conservation survey in report form, a ground penetrating radar technical report, terrain laser scanning (LiDAR) and orthophotos (geometrically corrected aerial photographs). The SGU geodata consist of a number of Geographical Information System (GIS) layers describing bedrock and soil types, and the nature conservation survey included accompanying, but incomplete, GIS data. This section consists of concise descriptions of the potential of each group of GIS layers or data, and is complemented by brief, bullet point summaries along with additional technical information in Appendix 1. Comments have been made where additional, related, data sources would be useful. Swedish terms are included in parenthesis where the term differs significantly from the English equivalent.

    A final summary provides a compact overview of the main points of the report before providing some conclusions and ideas for further work. This is in turn followed by a list of ideas for enhancing the efficiency with which the types of data discussed can be used in infrastructure projects which have a potential to impact on archaeology/cultural heritage.

    References are provided to support important or potentially contentious points or where further reading or research would be advised for a more comprehensive understanding of relevant issues.

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  • 36.
    Burlin, Jesper
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Geoenergi med och utan värmepump2017Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete utfördes på uppdrag av Umeå Kommun. Uppgiften bestod av att utvärdera dagens användning av en borrhålsbrunn samt undersöka vad som är det optimala användningsområdet för borrhålsbrunnen. Borrhålsbrunnen används i dagsläget för att förvärma samt kyla utomhusluft in till kontorsbyggnaden Kubens ventilationsaggregat.

    Ventilationens förvärmning består av två delar, en markkanal och ett geoenergibatteri. Viktiga parametrar hos förvärmningen analyserades med hjälp av mätvärden för temperatur och flöde. Resultaten jämfördes därefter med alternativet att använda borrhålsbrunnen tillsammans med en värmepump. Då borrhålsbrunnens kapacitet inte var tillräcklig för att klara byggnadens hela uppvärmningsbehov, undersöktes det hur en värmepump skulle kunna köras i kombination med fjärrvärme. Två driftstrategier, Bas och Kapatoppar, undersöktes. Bas leverar en basproduktion under hela vinterperioden medan Kapatoppar startar vid -6°C för att sänka effekttoppar.

    Utvärderingen av förvärmningen visade att geoenergibatteriet är mer kompatibelt med ventilationsaggregat av VAV-typ (Variable Air Volume) än vad markkanalen är. Däremot är inte förvärmning i kombination med roterande värmeväxlare ett bra koncept för byggnaden som den används idag. På grund av att förvärmningen är placerad före den roterande värmeväxlaren så är bara 15-20 % av förvärmningseffekterna energibesparande. Detta kombinerat med en optimerad drift av aggregatet sett till tidsstyrning och behovsstyrning av flöde gör att förvärmningen har en liten påverkan både på byggnadens maximala effektbehov och totala energibehov.

    Att köra värmepump i kombination med fjärrvärme för uppvärmning var ekonomiskt lönsamt främst på grund av att värmepumpen kunde kapa byggnadens effektoppar. Kostnaden för storleken på den abonnerade effekten uppgår idag till drygt 40 % av den totala fjärrvärmekostnaden. Dagens relation mellan el- och fjärrvärmepriser bidrog naturligtvis också till att värmepumpsalternativet var lönsamt. För de undersökta förutsättningarna så blev paybacktiden för en värmepump med den lönsammaste driftstrategin, Bas, 4,4 år.

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  • 37.
    Burman, Lisa
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå Universitet.
    Potentialen av energilager för att tillgängliggöra kapacitet i elnät för framtida etableringar2024Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To enable the transition to a fossil-free society and ongoing urbanization, where new establishments emerge in the heart of the society, the Swedish electricity system faces new challenges. Building a new powerline to meet the increased power demand is an expensive process, and in an existing grid, there isn’t always room to build new power lines. This leads to a capacity shortage at the local level, fundamentally due to the grid being undersized in areas where there are old power lines with lower rated current. To meet the increased power demand that electrification entails and simultaneously make capacity available for new establishments within the existing grid infrastructure, the potential of energy storage is being evaluated against the traditional solution of building new power lines.

    The purpose of the present work was therefore to investigate whether energy storage can be a potential solution to make capacity available for future establishments in an area where there is a capacity shortage. The energy storage solutions were evaluated from an economic, environmental, and power quality perspective and compared to building a new power line. This was done from the perspective of a grid company, where neither the market of frequency stability nor the electricity price market were included in the analysis.

    Based on the existing theory of energy storage, battery storage was chosen as the potential solution. To narrow the scope of the work, an area in Piteå Municipality was selected where a new establishment demands a power with drawal of 3 MW and is located midway between two existing grid lines. Using one year of operational data for the affected grid lines and calculations of their rated current, the performance of the battery storage was simulated, evaluating different battery sizes and energy contents (C-rate). Since the Electricity Act does not allow grid companies to own energy storage, the economic aspect was evaluated based on two different cases of battery rental. The goal is to maintain redundancy with the adjacent grid line with the additional power with drawal of 3 MW, to manage a potential outage without extensive consequences for subscribers.

    The results of the calculations and simulations show that the current grid line can handle the extra 3 MW requested. However, the battery storage does not relieve the grid sufficiently to prevent exceedingthe maximum capacity of the grid during high loads while maintaining redundancy with the interconnected grid line. The battery storage needs to be larger than 3 MW to relieve the grid as required, which is not economically justifiable. Depending on the rental conditions of the battery storage and which revenues are considered, the profitability of battery storage varies, but with a battery size over 1 MW, regardless of rental conditions, it is not economically justifiable compared to a new power line, which has a significantly longer technical lifespan.

    For battery storage to be useful in the grid and make capacity available, the grid must have spare capacity. The results also show that the relationship between the size of the establishment and the size ofthe battery storage is not one-to-one, instead, the energy content of the battery storage must be significantly larger to cut the power peaks. An energy content of two times the power, for example, 1 MW and2 MWh, is required for the battery to be advantageous and generate load savings on the grid. However, the battery storage can still relieve the grid to some extent by helping to distribute the current load more evenly, which means that the rated current, which is the limiting factor for short power line lengths, is not exceeded as early. 

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  • 38.
    Burman, Simon
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energianalys av MVG-gallerian, samt en jämförelse av beräkningsprogram2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis has been carried out in the spring of 2013, on behalf of Sweco Systems in Umeå. The aim of this work was to evaluate the possibilities of using any energy simulation software in the work of mapping energy usage of existing facilities. In this study two of the softwares that is being used in the company are evaluated – VIP-Energy and IDA Indoor Climate and Energy.

    Initially a mapping of the energy usage was performed on the property Odin 12 in Umeå, which consists mainly of the mall MVG. The energy usage was then simulated with the two different softwares.

    The mapping of energy usage shows that the building has a low annually need of space heating. This is due to the fact that the consumption of electricity in the building is very high, which leads to very high internal loads and a low need for additional heating. For the same reason, a need of space cooling is present during the whole year.

    The evaluation of the two energy simulation softwares shows that VIP-Energy is a suitable program for energy mapping. The program is both simple and flexible which reduces the time needed for creating the model.  Considering the time for the actual calculations, VIP-Energy is the program that is by far the fastest.

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  • 39.
    Bäcklund, Johannes
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av fjärrvärme- och fjärrkylanätet på campus i Umeå: Energy efficiency of the district heating and cooling systems on campus in Umeå2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete utfördes på uppdrag av Akademiska Hus som äger och förvaltar fastigheterna på campus i Umeå. Projektet bestod av att utifrån en övergripande bild på det interna fjärrvärme- och fjärrkylanätet på campus, ta fram alternativa utformningar på systemet i syfte om att göra det mer energieffektivt.

    Systemets interna fjärrvärme- och fjärrkylanät VP100 och KB100 växlar över värme och kyla från Umeå Energi som sedan distribueras vidare till fjärrvärme- och fjärrkylacentraler på campus. Några av centralerna har egenproduktion där returledningen från KB100 går till en värmepump som producerar både värme och kyla. Producerad värme används till att förvärma returledningen från uppvärmningssystemen från de byggnader som hör till respektive central. När behovet av värme är tillräckligt stort är systemet, tack vare värmepumparna, självförsörjande gällande kyla. Produktion sker alltså endast under de perioder då det finns behov i uppvärmningssystemen. Det leder till att systemet tvingas köpa både värme och kyla samtidigt under sommaren då behovet av kyla i stort sett är konstant under året.

    Två alternativa utformningar till det befintliga systemet har undersökts. Det första fallet har som syfte att reducera värmeförlusterna i VP100. Det andra fallet byggdes vidare på det första fallet med syftet att utvidga arbetsområdet för värme- och kylproduktionen i värmepumparna.

    Resultatet visar att det finns potential att mer än halvera värmeförlusterna i det befintliga VP100 och att produktionen av värme och kyla skulle kunna öka med 10 % respektive 6 %. Totalt skulle systemet kunna spara drygt 1,3 miljoner kWh per år genom en kombination av de två alternativa utformningarna. För att däremot få energibalans i systemet där det aldrig behöver köpas både värme och kyla samtidigt bör andra effektiviseringsåtgärder övervägas. 

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  • 40. Carter, Ellison
    et al.
    Lam, Nicholas
    Chafe, Zoe
    Carvalho, Ricardo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Shan, Ming
    Ackerly, John
    Lancey, Forrest
    Household energy transitions to address air pollution exposure, health, and climate burdens associated with solid fuel burning2018In: Household energy transitions to address air pollution exposure, health, and climate burdens associated with solid fuel burning, Philadelphia, 2018Conference paper (Other academic)
    Abstract [en]

    Residential space heating and cooking are critical household energy service needs worldwide. Household transitions to clean-burning fuels at population scales are needed that do not contribute to poor indoor and outdoor air quality and the potential associated exposure, health, and climate burdens. We propose to discuss and debate research, implementation needs, and advances related to use of solid fuel for meeting residential energy needs with an express focus on residential heating demand, which has been less studied than residential cooking.We aim to identify knowledge gaps in the field of household energy systems in resource-constrained communities, set research priorities to address these gaps, and highlight opportunities for interdisciplinary and transnational learning and collaboration. 

  • 41.
    Carvalho, Ricardo L.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Centre for Environmental and Marine Studies, Dept. of Environment and Planning, University of Aveiro, Aveiro, Portugal; Laboratory of Renewable Energy and Environmental Comfort, Institute of Education, Science and Technology of Ceará, Fortaleza, Brazil.
    Lindgren, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lopez, N.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nyambane, Anne
    Nyberg, Gert
    Diaz-Chavez, Rocio
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Household air pollution mitigation with integrated biomass/cookstove strategies in Western Kenya2019In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 131, p. 168-186Article in journal (Refereed)
    Abstract [en]

    Traditional cooking is today's largest global environmental health risk. Over 640 million people in Africa are expected to rely on biomass for cooking by 2040. In Kenya, cooking inefficiently with wood and charcoal persists as a cause of deforestation and household air pollution. This research analyses the effects of four biomass cookstove strategies on reducing air pollutant emissions in Kisumu County between 2015 and 2035 using the Long-Range Energy Alternatives Planning system. The Business as Usual scenario (BAU) was developed considering the historical trends in household energy use. Energy transition scenarios to Improved Cookstoves (ICS), Pellet Gasifier Stoves (PGS) and Biogas Stoves (BGS) were applied to examine the impact of these systems on energy savings and air pollution mitigation. An integrated scenario (INT) was evaluated as a mix of the ICS, PGS and BGS. The highest energy savings, in relation to the BAU, are achieved in the BGS (30.9%), followed by the INT (23.5%), PGS (19.4%) and ICS (9.2%). The BGS offers the highest reduction in the GHG (37.6%), CH4 (94.3%), NMVOCs (85.0%), CO (97.4%), PM2.5 (64.7%) and BC (48.4%) emissions, and the PGS the highest reduction in the N2O (83.0%) and NOx (90.7%) emissions, in relation to the BAU.

  • 42.
    Carvalho, Ricardo L.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Centre of Environment and Marine Studies, University of Aveiro, Aveiro, Portugal.
    Yadav, Pooja
    Dept. of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Lindgren, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    García-López, Naxto
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nyberg, Gert
    Dept. of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Diaz-Chavez, Rocio
    Stockholm Environment Institute, Africa Centre, c/o World Agroforestry Centre, P.O. Box 30677, Nairobi, Kenya.
    Upadhyayula, Venkata Krishna Kumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Athanassiadis, Dimitris
    Dept. of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Bioenergy strategies to address deforestation and household air pollution in western Kenya2019In: European Biomass Conference and Exhibition Proceedings, ETA-Florence Renewable Energies , 2019, p. 1536-1542Conference paper (Refereed)
    Abstract [en]

    Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden disease due to household air pollution. The Long-Range Energy Alternatives Planning (LEAP) system and the Life-Cycle Assessment tool Simapro 8.5 were applied for analyzing biomass strategies for the region. The calculation of the residential energy consumption and emissions was based on scientific reviews and original data from experimental studies. The research shows the effect of four biomass strategies on the reduction of wood fuel use and short-lived climate pollutant emissions. A Business As Usual scenario (BAU) considered the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) considered the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluated a mix of the ICS, PGS and BGS. The study shows that, energy use will increase by 8% (BGS), 20% (INT), 26% (PGS), 42% (ICS) and 56% (BAU). The BGS has the lowest impact on global warming, particle formation, terrestrial acidification, fossil resource scarcity, water consumption, as well as on eutrophication followed by the PGS and INT.

  • 43.
    Carvalho, Ricardo
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindgren, Robert
    García-Lopez, Natxo
    Nyberg, Gert
    Boman, Christoffer
    Household Bioenergy Transitions with Alternative Biomass Feedstocks and Technologies: An Integrated System to Mitigate Environmental Risks in Western Kenya2018In: / [ed] École Polytechnique Fédérale de Lausanne, UNESCO, Lausanne, 2018Conference paper (Other academic)
    Abstract [en]

    In Kenya, over 50% of the total primary energy consumption is from traditional solid-fuel cooking, being this a major cause of deforestation and household air pollution (HAP). Western Kenya has an agricultural biofuel feedstock of over 1.9 million Mt, which could be processed to supply cookstoves with crop-residue pellets and improved wood fallows. The sociotechnical viability of two novel bioenergy value chains were analysed using the Long-Range Energy Alternatives Planning system. Three scenarios of transition to efficient cookstoves and decentralized biofuel and electricity production systems were tested. In the “Optimal scenario”, the current feedstock in the Kisumu and Siaya counties could satisfy over 80% of the cooking energy demand by 2030. Here, the net greenhouse gas emissions from charcoal production and HAP could be reduced by 87% to 12.6 thousand Mt CO2e. Further work should integrate socioeconomic indicators reflecting additional local/regional stakeholders´ collaboration channels (cost-effective) to support the bioenergy transitions. 

  • 44.
    Carvalho, Ricardo
    et al.
    Danish Building Research Institute, Aalborg University, Copenhagen, Denmark; Centre for Environmental and Marine Studies, University of Aveiro, Campus Universitário de Santiago, Portugal.
    Vicente, Estela
    Tarelho, Luís
    Jensen, Ole Michael
    Wood stove combustion air retrofits: a low cost way to increase energy savings in dwellings2018In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 164, p. 140-152Article in journal (Refereed)
    Abstract [en]

    In Europe, wood-fired stoves remain as major renewable household heating and emission sources. This study focused on improving the performance of a wood stove (natural draft) traditionally used in Portugal by the adoption of alternative combustion air retrofits. Additionally, the performance of a new pellet stove (forced-air) was determined to investigate the highest achievable goal for solid-fuel stoves. In the wood stove, an outer chimney component was installed around the existing chimney to allow the vertical admission of outdoor air that was preheated before entering the combustion chamber. This measure increased the thermal efficiency of the wood stove from 62% to up to 79%. Another component was used to administrate secondary air to the wood stove reducing the carbon monoxide emissions by 39% to 2808 mg Nm−3. The two retrofits enhanced a more stable heat release from the wood stove, which reached a thermal efficiency 11% lower than that achieved by the pellet stove. This research suggests that retrofitting stoves with chimney components that allow the admission of combustion air can substantially increase energy savings in dwellings. Further efforts should focus on improving the interplay between the outdoor air and secondary air admission to achieve higher emission reductions at low-cost.

  • 45.
    Chavez-Rodriguez, Mauro F.
    et al.
    Energy Planning Program, COPPE/UFRJ - Universidade Federal do Rio de Janeiro, Cidade Universitaria, Centro de Tecnologia, Rio de Janeiro, RJ, Brazil.
    Carvajal, Pablo E.
    UCL Energy Institute, University College London, UK.
    Martinez Jaramillo, Juan E.
    Institución Universitaria Politécnico Grancolombiano, Bogotá, Colombia .
    Egüez, Alejandro
    Umeå University, Faculty of Social Sciences, Center for Environmental and Resource Economics (CERE).
    Gonzalez Mahecha, Rosa Esperanza
    Energy Planning Program, COPPE/UFRJ - Universidade Federal do Rio de Janeiro, Cidade Universitaria, Centro de Tecnologia, Rio de Janeiro, RJ, Brazil.
    Schaeffer, Roberto
    Energy Planning Program, COPPE/UFRJ - Universidade Federal do Rio de Janeiro, Cidade Universitaria, Centro de Tecnologia, Rio de Janeiro, RJ, Brazil.
    Szklo, Alexandre
    Energy Planning Program, COPPE/UFRJ - Universidade Federal do Rio de Janeiro, Cidade Universitaria, Centro de Tecnologia, Rio de Janeiro, RJ, Brazil.
    Lucena, Andre F. P.
    Energy Planning Program, COPPE/UFRJ - Universidade Federal do Rio de Janeiro, Cidade Universitaria, Centro de Tecnologia, Rio de Janeiro, RJ, Brazil.
    Arango Aramburo, Santiago
    Department of Computing and Decision Sciences, Universidad Nacional de Colombia, Medellín, Colombia .
    Fuel saving strategies in the Andes: long-term impacts for Peru, Colombia and Ecuador2018In: Energy Strategy Reviews, ISSN 2211-467X, E-ISSN 2211-4688, Vol. 20, p. 35-48Article in journal (Refereed)
    Abstract [en]

    Crude oil exports and imports play a crucial role in the trade balance of Peru, Colombia and Ecuador. These countries are looking into fossil fuel saving measures as a way to deal with increasing demands and decreasing oil production rates. However, studies about the long-term effects of these measures is lacking. Using a combination of energy simulation technics, 17 fuel saving strategies ranging from fuel switching to the investment in underground transport and hydropower capacity expansion were modelled and assessed to evaluate their long-term effect on fossil fuels demand reduction. Our results show that the full implementation of strategies can account for cumulative oil savings of over 550 million barrels of oil by 2030. Findings also point out that Ecuador and Colombia could face the transition from net oil-exporters to importers as soon as the end of the next decade.

  • 46.
    Cheng, Xiaogang
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China; School of Electrical Engineering and Computer Science, Royal Institute of Technology, Stockholm, Sweden.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi'an, China.
    Liu, Guoqing
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    A total bounded variation approach to low visibility estimation on expressways2018In: Sensors, E-ISSN 1424-8220, Vol. 18, no 2, article id 392Article in journal (Refereed)
    Abstract [en]

    Low visibility on expressways caused by heavy fog and haze is a main reason for traffic accidents. Real-time estimation of atmospheric visibility is an effective way to reduce traffic accident rates. With the development of computer technology, estimating atmospheric visibility via computer vision becomes a research focus. However, the estimation accuracy should be enhanced since fog and haze are complex and time-varying. In this paper, a total bounded variation (TBV) approach to estimate low visibility (less than 300 m) is introduced. Surveillance images of fog and haze are processed as blurred images (pseudo-blurred images), while the surveillance images at selected road points on sunny days are handled as clear images, when considering fog and haze as noise superimposed on the clear images. By combining image spectrum and TBV, the features of foggy and hazy images can be extracted. The extraction results are compared with features of images on sunny days. Firstly, the low visibility surveillance images can be filtered out according to spectrum features of foggy and hazy images. For foggy and hazy images with visibility less than 300 m, the high-frequency coefficient ratio of Fourier (discrete cosine) transform is less than 20%, while the low-frequency coefficient ratio is between 100% and 120%. Secondly, the relationship between TBV and real visibility is established based on machine learning and piecewise stationary time series analysis. The established piecewise function can be used for visibility estimation. Finally, the visibility estimation approach proposed is validated based on real surveillance video data. The validation results are compared with the results of image contrast model. Besides, the big video data are collected from the Tongqi expressway, Jiangsu, China. A total of 1,782,000 frames were used and the relative errors of the approach proposed are less than 10%.

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  • 47.
    Cheng, Xiaogang
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Nanjing Univ Posts & Telecommun, Coll Telecommun & Informat Engn, Nanjing, Jiangsu, Peoples R China; Royal Inst Technol, Sch Comp Sci & Commun, Stockholm, Sweden.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Liu, Guoqing
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    A variational approach to atmospheric visibility estimation in the weather of fog and haze2018In: Sustainable cities and society, ISSN 2210-6707, Vol. 39, p. 215-224Article in journal (Refereed)
    Abstract [en]

    Real-time atmospheric visibility estimation in foggy and hazy weather plays a crucial role in ensuring traffic safety. Overcoming the inherent drawbacks with traditional optical estimation methods, like limited sampling volume and high cost, vision-based approaches have received much more attention in recent research on atmospheric visibility estimation. Based on the classical Koschmieder's formula, atmospheric visibility estimation is carried out by extracting an inherent extinction coefficient. In this paper we present a variational framework to handle the nature of time-varying extinction coefficient and develop a novel algorithm of extracting the extinction coefficient through a piecewise functional fitting of observed luminance curves. The developed algorithm is validated and evaluated with a big database of road traffic video from Tongqi expressway (in China). The test results are very encouraging and show that the proposed algorithm could achieve an estimation error rate of 10%. More significantly, it is the first time that the effectiveness of Koschmieder's formula in atmospheric visibility estimation was validated with a big dataset, which contains more than two million luminance curves extracted from real-world traffic video surveillance data.

  • 48. Chilkoor, Govinda
    et al.
    Upadhyayula, Venkata Krishna Kumar
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gadhamshetty, Venkataramana
    Koratkar, Nikhil
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sustainability of renewable fuel infrastructure: a screening LCA case study of anticorrosive graphene oxide epoxy liners in steel tanks for the storage of biodiesel and its blends2017In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, no 2, p. 141-153Article in journal (Refereed)
    Abstract [en]

    Biodiesel is a widely used fuel that meets the renewable fuel standards developed under Energy Policy Act of 2005. However, biodiesel is known to pose a series of abiotic and biotic corrosion risks to storage tanks. A typical practice (incumbent system) used to protect the tanks from the risks include: (i) coat the interior surface of the tank with solvent free epoxy (SFE) liner, and (ii) add a biocide in the tank. We present a screening-level, life cycle assessment study to evaluate and compare the environmental performance of graphene-oxide (GO)-epoxy (GOE) liner with the incumbent system. TRACI is used as an impact assessment tool to model midpoint environmental impacts for the ten categories: global warming potential (GWP, kg CO2 eq.); acidification potential (AP, kg SO2 eq.); potential human health damage impacts due to carcinogens (HH-CP, CTUh) and non-carcinogens (HH-NCP, CTUh); potential respiratory effects (REP, kg PM2.5 eq); eutrophication potential (EP, kg N eq); ozone depletion potential (ODP kg CFC-11 eq); ecotoxicity potential (ETXP, CTUe); smog formation potential (SFP kg O3 eq); and fossil fuel depletion potential (FFDP MJ surplus). The equivalent functional unit of the LCA study is designed to protect the 30 m2 of the interior surface (unalloyed steel sheet) of a 10,000 liters biodiesel tank against abiotic and biotic corrosion during its service life of 20 years. Overall, this LCA study highlights an improved environmental performance for the GOE liner compared to the incumbent system; GOE-liner system showed: 91% lower ODP impacts; 59% smaller for REP; 62% smaller for AP; 67-69% smaller for GWP and HH-CP; 72-76% smaller for EP, SFP, and FFDP; and 81-83% smaller for ETXP and HH-NCP categories. The scenario analysis study reveals that these potential impacts change by less than 15% when the GOE liners are functionalized with silanized-GO nanosheets or GO-reinforced, polyvinyl carbazole to improve the antimicrobial properties. The results from uncertainty analysis indicate that the impacts for the incumbent system are more sensitive to changes in key modeling parameters compared to that for GOE liner system.

  • 49.
    Da Alesandro, Sofia
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvinning av snökyla som kylmetod: En förstudie åt Akademiska Hus i Luleå2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Det finns stora utmaningar i dagens samhälle för att uppnå målet att inte ha några nettoutsläpp av växthusgaser senast 2045. Därför undersöks snökylesystem i en öppen bassäng i denna rapport då detta är en metod som bidrar både till hållbar utveckling och även billigare elanvändning. Systemet tillåter även föroreningar från snön att hanteras på ett miljövänligt sätt. Syftet med arbetet är att Akademiska Hus i Luleå under en längre period har varit intresserad av att undersöka om snökyla skulle kunna täcka kylbehovet för Luleå tekniska universitet (LTU) under årets varma säsong, samt undersöka möjligheten att koppla in andra potentiella företag i närheten till samma system för att fler byggnader ska kunna utvinna snökyla. Arbetet är inspirerat från den fungerande snökyleanläggningen i Sundsvall, där denna metod har lett till en minskning på 90 % av både elanvändning och växthusgasutsläpp och som även lett till ekonomiska fördelar för Sundsvalls sjukhus. Fördelen med snökyla är att både snö och is har sin frys- och smältpunkt vid 0 °C vilket resulterar i att snö har en utmärkt egenskap vid lagring och utvinning av kyla.

    Under åren 1991-2020 skiljde årsmedeltemperaturen mellan Luleå och Sundsvall med 1,4 °C och klimatet i Luleå förväntas i framtiden att bli blötare och varmare. Marken som snökyleanläggningen är tänkt att placeras på är en befintlig snödeponi cirka 1,5 km bort från LTU och troligtvis består den av jordarten morän och lera-silt där den förstnämnda möjligen kan bestå av grövre material. Det är fördelaktigt att bygga på mark med grövre material för att undvika tjällyftning. Utformning av optimala bassängdimensioner är okänt däremot är det känt att en kompakt lagring är fördelaktigt för att minska naturliga snösmältningar då snösmältningen är proportionerlig mot bottenarean. De naturliga snösmältningarna kan delas upp i faktorerna luft, regn och mark. Den naturliga snösmältningen domineras av värmeöverföringen från luften och därmed spelar värmeisoleringen ovanpå snön en stor roll.

    I arbetet har beräkningar av naturliga snösmältningar orsakade av värmeledning från marken, värmeöverföring från luft och regn genomförts. Även generella uppskattningar och jämförelser av investeringskostnader samt olika potentiella kylbehov hos kunder har sammanställts. I den ekonomiska kalkylen testades olika potentiella genomsnittliga flöden för driftsäsongen och även olika delfall för investeringskostnader för att se påverkan på den ekonomiska lönsamheten. Driftkostnader för snökylesystemets cirkulationspump jämfördes med kylmaskiner med antagandet att intäkten för mängden snö som tas emot är ekvivalent med snökylesystemets resterande underhålls- och driftkostnader som kan uppstå för snöhantering etcetera. Ytterligare ett antagande vid driften är att elanvändningen och flödet följde ett linjärt samband.

    Resultatet visade att driftkostnaden för snökylesystemets cirkulationspump hade en avsevärt mindre driftkostnad än kylmaskiner. Den ekonomiska kalkylen visade på att investering av snökyleanläggningen var lönsam för driftsäsongens höga medelflöden för alla delfall som testades och att återbetalningstiden kan minskas med bättre utredning och fördelning på investeringskostnaden. Resultatet visade även att störst påverkan av naturlig snösmältning kommer från värmeöverföringen från luften, cirka 81 %. Resterande faktorer till naturlig snösmältning bestod av cirka 4 % respektive 14 % av värmeöverföring och värmeledning från regn och mark. Resultatet påvisade att en större volym ger minskade snöförluster.

    Slutsatsen från denna rapport är att det är fullt möjligt att implementera stora snökyleanläggningar och att Luleå har ett gynnsamt klimat för denna typ av anläggning. I förlängningen kan utvinning av snökyla bidra till både ekonomisk och ekologisk lönsamhet.

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  • 50.
    Daniel, Petrovic
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Underlag till byte av värmekälla för skola i Adak.: Energi- och kostnadsbesparingar redovisas som kan göras för investering i ny värmekälla.2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport är skriven mot Malå kommun och syftar att ta fram en grund om vilken besparing som kan göras vid byte av energikälla för att sänka skolans energikostnader på ett miljövänligare sätt. Genom att göra en empirisk energibalans och beräkna den dimensionerande effekten ta fram underlag för rätt val av värmekälla. Den energikälla som idag betjänar skolans värmesystem är en gammal oljepanna som även förser en kallställd del av skolan med värme som inte används. Detta underhåll av den kallställda delen resulterar i att skolan idag lider av stora energiförluster. Diskussion har förts av Malås kommunstyrelse om att riva den kallställda delen. 

    En energikartläggning har gjorts av skolans fastighet för att utreda vilka alternativa uppvärmningslösningar som kan tillämpas. Avgränsning av uppvärmningslösningar har gjorts till värmepump och pelletspanna. För att kunna jämföra de olika uppvärmningslösningarna mot varandra har en livscykelkostnadsanalys (LCC) gjorts. Att bilda uppfattning om hur lång tid det skulle ta att betala av de olika investeringarna har även en pay off tid tagits fram.

    För en så verklighetstrogen bild som möjligt har problemet bemöts från tre olika angreppsvinklar. En överslagsberäkning av energifakturor inledde den första offensiven för att ta reda på nuvarande energibehov under dagens förutsättningar. Denna följdes av manuella energiberäkningarna av fastighetens olika byggnader. För att få stöd för de manuella beräkningarna gjordes energisimuleringar i programmet VIP-energy. För att sätta siffrorna i en kontext jämfördes dessa med statistiska nyckeltal hämtade från boverkets och energimyndighetens gemensamma rapport STIL 2. 

    Resultaten tyder på att värmepumpen är den mest lönsamma investeringen enligt livscykelkostnadsanalysen med en kalkylperiod på 20 år. Skolans teoretiska effektbehov som värmekällan bör dimensioneras efter är 77 kW. Den LCC de bägge värmekällorna visar i dagens penningvärde är:

    Värmepump: 2,1 Mkr

    Pelletspanna: 3,4 Mkr

     

    Med en pay off tid på 4,5 år jämfört med 18,5 år för pelletspanna visade sig värmepumpen även där som den lönsammare investeringen.

    Då den årlig uppvärmningen för skolan är 198 990 kWh kan 70-140 kkr sett till dagens penningvärde sparas per år beroende på uppvärmningslösning och kommunens beslut om fastighetens kallställda del.

    En hypotetisk analys av den årliga prisutvecklingen med hänsyn till inflationen för de olika energislagen olja, pellets och el har gjorts som antyder på att 50-80 % kostnadsbesparingspotential kan uppnås genom att byta från befintligt värmesystem med olja till pellets eller värmepump över kommande 20 års period.     

    Det radiatorsystem som idag används uppskattas kunna förse skolan med nödvändigt värmebehov utan att behöva om-dimensioneras vid installering av ny värmekälla. Därför föreslås att Malå kommun investerar i en värmepump som ersätter den befintlig oljepanna i Adaks förskola med hänsyn till effektivare slutanvändning av den inköpta energin.

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