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  • 1.
    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 universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 agents2023Inngår i: Energy Reports, E-ISSN 2352-4847, Vol. 9, s. 4971-4983Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 2.
    Adolfsson, Sebastian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Expanding operation ranges using active flow control in Francis turbines2014Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    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.

    Fulltekst (pdf)
    Lastområdesutvidgning med aktiv flödeskontroll i Francisturbiner
  • 3.
    Allard, Ingrid
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Achieving building energy performance: requirements and evaluation methods for residential buildings in Sweden, Norway, and Finland2015Licentiatavhandling, med artikler (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    fulltext
  • 4.
    Allard, Ingrid
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energy performance criteria for residential buildings: A comparison of Finnish, Norwegian, Swedish, and Russian building codes2021Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 250, artikkel-id 111276Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 5.
    Allard, Ingrid
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Hassan, Osama
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Methods for air tightness analysis for residential buildings in Nordic countries2012Inngår i: Methods for air tightness analysis forresidential buildings in Nordic countries, Southampton: WIT Press, 2012, s. 311-322Konferansepaper (Fagfellevurdert)
    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.

  • 6.
    Allard, Ingrid
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Hassan, Osama A. B.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Methods for energy analysis of residential buildings in Nordic countries2013Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 22, s. 306-318Artikkel, forskningsoversikt (Fagfellevurdert)
    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.

  • 7.
    Allard, Ingrid
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energy performance indicators in the Swedish building procurement process2017Inngår i: Sustainability, E-ISSN 2071-1050, Vol. 9, nr 10, artikkel-id 1877Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 8.
    Allard Stolterman, Ingrid
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Regulating energy performance of residential buildings in cold climate: a study of indicators, criteria, and evaluation methods2021Doktoravhandling, med artikler (Annet vitenskapelig)
    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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  • 9.
    Almgren, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Effekten av dagsljus- och närvarostyrd LED-belysning i en befintlig kontorsbyggnad ur energi-, ekonomi- och ljusmiljösynpunkt2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Energieffektiviserande åtgärder har stor betydelse för den totala effekten på vårt klimat. Lägre energiåtgång leder till reducerade koldioxidutsläpp och att naturens resurser inte belastas lika hårt. En av de mest kostnadseffektiva åtgärderna för att minska byggnaders miljöpåverkan har visats vara att investera i den energieffektiva belysningsteknik LED, och i kombination med dagsljus- och närvarostyrning finns en stor potential att spara energi.Syftet med detta examensarbete är att studera hur bland annat elförbrukningen, värme- och kylbehovet, ljusmiljön och driftkostnaderna för en belysningsanläggning påverkas av att byta ut traditionell belysning mot LED i befintliga kontorslokaler, samt implementering av dagsljus- och närvarostyrning. Detta har gjorts genom bland annat el- och ljusmätningar, flertalet datorsimuleringar, enkätundersökningar och intervjuer som en del i ett befintligt projekt med ÅF Lighting, som gick ut på att två olika LED-lösningar installerades på två kontorsplan på ÅF:s huvudkontor i Solna. Med hjälp av datorsimuleringar har undersökningar gjorts av bland annat kontorens tillgång till dagsljus i DIVA-for-Rhino, kontorens ljusnivåer i diaLUX, hur kyl - och värmebehovet påverkas i IDA ICE 4.7, ekonomiska besparingar i ecoCALC samt belysningens elförbrukning i Mitec Monitor.Elmätningar under en månad av de nya belysningsanläggningarna på plan 5 och plan 10 visade på en reducering av belysningens elförbrukning på 71,6 % respektive 68,1 % under denna period.Energisimuleringar över ett år i IDA ICE visade att den totala energianvändningen för båda kontorslandskapen reducerades med cirka 12-14 % efter bytet till LED-belysningen och implementeringen av dagsljus- och närvarostyrning. Största faktorn till denna besparing är att kylbehovet för plan 5 och plan 10 kunde reduceras med 19 % respektive 17 %, eftersom den mer energieffektiva belysningen och styrningen av denna genererar mindre värme än den befintliga belysningen. Simuleringarna visade även att belysningens totala årliga elförbrukning reducerades med 70 % på plan 5 och 63 % på plan 10.En grundlig LCC för de nya belysningslösningarna på plan 5 och plan 10 visade att investeringskostnaderna för de nya LED-lösningarna är högre än den totala driftkostnaden över livscykeln för den befintliga belysningen. Dock är driftkostnaderna för de nya lösningarna mindre än en tredjedel av kostnaderna att driva den befintliga belysningen, och de totala koldioxidutsläppen kan reduceras med närmare 70 % i och med utbytet.Denna fallstudie har visat att det finns enorm potential att spara energi och minska driftkostnaderna genom att investera i energieffektiv LED-belysning i kombination av dagsljus-och närvarostyrning, samtidigt som det kan ha positiv inverkan på ljusmiljön. Dock är investeringskostnaderna av de nya LED-lösningarna för stora för att installation av just dessa lösningar ska vara ekonomiskt försvarbart idag.

  • 10.
    Almstedt, Kalle
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energieffektiviseringsåtgärder på Gustavsvik resorts AB2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    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. 

    Fulltekst (pdf)
    Energieffektiviseringsåtgärder på Gustavsvik resorts AB
  • 11.
    Andersson, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 poäng / 15 hpOppgave
    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.

    Fulltekst (pdf)
    fulltext
  • 12. Asthana, Arvind
    et al.
    Nair, Gireesh
    ?.
    Big efficiency in small scale2001Annet (Annet (populærvitenskap, debatt, mm))
  • 13.
    Auland, Clara
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Storskaligt logistiksystem för vätgastransport2021Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Energiomställningen är avgörande för att begränsa de globala koldioxidutsläppen. Det blir det allt viktigare att hitta sätt att ta tillvara på elöverskott och kunna lagra energi från förnybara energikällor som vind och sol. Vätgas är en energibärare och har stor potential för att ha en nyckelroll i ett hundraprocentigt förnybart energisystem. Syftet med studien var att undersöka förutsättningarna för ett ekonomiskt och tekniskt håll- bart logistiksystem för vätgastransport. Målet var att beräkna överföringskostnader och jämföra olika tekniker för transport av vätgas. Studien inleddes med en djupgående litte- raturstudie och omvärldsanalys. Därefter valdes två olika fall i norra Sverige och utifrån de förutsättningar som fanns på platserna jämfördes transport via pipeline, vägtransport och järnvägstransport.

    Resultaten för vägtransport via komprimerad form tyder på att det krävs ett stort antal transporter för att leverera den analyserade mängden i de olika fallen vilket resulterar i höga kostnader. Transport via järnväg tyder på relativt hög investeringskostnad och ingen större skillnad mellan fallen. Resultaten tyder på att transport via pipeline har relativt låga överföringskostnader för båda fallen och man kan se en skillnad i investeringskostnad mellan fallen. Överföringskostnader via pipeline tyder på lägre kostnader än att överföra el.

    Överföringskostnader kan bero på olika faktorer som förutsättningar på platsen, elkostnader, avstånd och volym. Det finns osäkerheter i resultaten för vägtransport och järnväg vilket gör det svårt att dra slutsaster utifrån den data som presenteras. Jämförelsen mellan vätgas och el ska ses som en grov uppskattning på grund av de osäkerheter som finns kopplat till elöverföringen.

    Fulltekst (pdf)
    fulltext
  • 14.
    Axelsson, Sebastian
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Utredning av en potentiell installation av FTX-ventilation med värmeåtervinning2018Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med detta examensarbete är huvudsakligen att studera och undersöka en specifik och befintlig bostadsförenings möjlighet att bidra till att främja en hållbar framtid i en större skala. Det vill säga minska dess påfrestningar på natur och miljö i form av onödigt höga energiförbrukningar. Projektet ska dessutom visa på att det i många fall även kan vara lönsamt att investera i ett nytt energisnålt system. Efter att studerat bostadsföreningens fastighets struktur och utformning, konstaterades att ett nytt ventilationssystem med värmeåtervinning skulle vara aktuellt.

    Bostadsföreningen omfattas av 83 stycken lägenheter på en total boyta av 5 474 m2 och är lokaliserad i norra Sverige där temperaturer på -30 °C inte är otänkbart. Fastigheten bedrivs idag av ett frånluftssystem för att transportera bort förbrukad luft, frisk luft strömmar in genom utomhusventiler direkt in i bostaden. Eftersom fastigheten är belägen på en plats där det förekommer kalla utomhustemperaturer många delar av året är det ogynnsamt att transportera in kall luft direkt in i bostaden utan förvärmning. Detta betyder att den aktuella fjärrvärmeförbrukningen till radiatorerna maximeras för att möta ett gott inomhusklimat.

    Projektet som har genomförts visar att det framförallt finns en möjlighet att installera ett FTX-system i bostaden. I många fall är det brist på utrymme som motstrider en installation. Bortsett från utrymmet visar resultatet att fjärrvärmeförbrukningen kan halveras med 600 MWh per år. Detta skulle innebära en besparing på 411 Kkr per år för hela fastigheten. Kostnaden för det material som krävs uppges till cirka 3,1 Mkr. Detta betyder att investeringen är återbetalad efter cirka 7-8 år. Siffrorna nämnt ovan motsvarar det materiella paket som redovisas i rapportens resultat och förutsätter att de befintliga frånluftskanaler som finns i bostaden idag kvarstår men utökas. Utformningen på det förslag som lagts fram bygger på en balanserad ventilation med värmeåtervinning (80 %) med separata aggregat för varje lägenhet.

    Fulltekst (pdf)
    Master Thesis
  • 15.
    Azizi, Shoaib
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    A multi-method assessment to support energy efficiency decisions in existing residential and academic buildings2021Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    PhD Dissertation_Shoaib Azizi
    Download (pdf)
    Posting sheet
  • 16.
    Azizi, Shoaib
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Adoption of Energy Efficiency Measures in Renovation of Single-Family Houses: A Comparative Approach2020Inngår i: Energies, E-ISSN 1996-1073, Vol. 13, nr 22, artikkel-id 6042Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 17.
    Azizi, Shoaib
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Analysing the house-owners’ perceptions on benefits and barriers of energy renovation in Swedish single-family houses2019Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 198, s. 187-196Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 18.
    Azizi, Shoaib
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Olofsson, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Demand-controlled energy systems in commercial and institutional buildings: a review of methods and potentials2019Inngår i: eceee 2019 Summer Study on energy efficiency:: Is efficient sufficient?, European Council for an Energy Efficient Economy (ECEEE), 2019, s. 1444-1450Konferansepaper (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 19.
    Banerjee, Sourasekhar
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    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 grid2022Inngår i: Deep learning in data analytics: recent techniques, practices and applications / [ed] Debi Prasanna Acharjya; Anirban Mitra; Noor Zaman, Springer, 2022, , s. 19s. 221-239Kapittel i bok, del av antologi (Fagfellevurdert)
    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.

  • 20.
    Björnfot, Mikael
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    COMPUTATIONAL FLUID DYNAMICS MODELING FOR BENT SPILLWAY CHANNEL: Numerical validation of a small scale physical model2020Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    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.

    Fulltekst (pdf)
    fulltext
  • 21.
    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 universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 effectiveness2023Inngår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 10, artikkel-id 2654Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 22.
    Broberg, Thomas
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Nationalekonomi. Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för miljö- och naturresursekonomi (CERE).
    Egüez, Alejandro
    Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för miljö- och naturresursekonomi (CERE). Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Nationalekonomi.
    Kazukauskas, Andrius
    Vilnius University.
    Effects of energy performance certificates on investment: A quasi-natural experiment approach2019Inngår i: Energy Economics, ISSN 0140-9883, E-ISSN 1873-6181, Vol. 84, artikkel-id 104480Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 23.
    Burlin, Jesper
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Geoenergi med och utan värmepump2017Independent thesis Advanced level (professional degree), 300 hpOppgave
    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.

    Fulltekst (pdf)
    fulltext
  • 24.
    Burman, Lisa
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Umeå Universitet.
    Potentialen av energilager för att tillgängliggöra kapacitet i elnät för framtida etableringar2024Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    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. 

    Fulltekst (pdf)
    fulltext
  • 25.
    Burman, Simon
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energianalys av MVG-gallerian, samt en jämförelse av beräkningsprogram2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    På uppdrag av Sweco Systems i Umeå har detta examensarbete utförts under våren 2013. Syftet var att undersöka huruvida något av de energiberäknings-program som används på företaget kan anses vara lämpligt vid energikartläggningar av befintliga fastigheter.

    Inledningsvis utfördes en energikartläggning av fastigheten Odin 12 i Umeå, som i huvudsak utgörs av gallerian MVG. Med resultaten från denna energikartläggning som grund beräknades därefter fastighetens energianvändning i två olika program – VIP-Energy och IDA Indoor Climate and Energy.

    Resultaten från den inledande kartläggningen visar att fastigheten har ett lågt behov av fjärrvärme, vilket förklaras av fastighetens höga elförbrukning. Den stora användningen av el genererar stora mängder internvärme som, förutom att sänka fjärrvärmebehovet, även medför att fastigheten under hela året har ett kylbehov.

    Utvärderingen av de två beräkningsprogrammen visar att VIP-Energy är ett lämpligt program att använda vid energikartläggningar. Programmet är enkelt och flexibelt, vilket medför att uppbyggandet av en beräkningsmodell går relativt snabbt. Vad gäller tidsåtgången för själva simuleringarna är också VIP-Energy det program som är klart snabbast.

    Fulltekst (pdf)
    fulltext
  • 26.
    Bäcklund, Johannes
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 poäng / 30 hpOppgave
    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. 

    Fulltekst (pdf)
    fulltext
  • 27. Carter, Ellison
    et al.
    Lam, Nicholas
    Chafe, Zoe
    Carvalho, Ricardo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Shan, Ming
    Ackerly, John
    Lancey, Forrest
    Household energy transitions to address air pollution exposure, health, and climate burdens associated with solid fuel burning2018Inngår i: Household energy transitions to address air pollution exposure, health, and climate burdens associated with solid fuel burning, Philadelphia, 2018Konferansepaper (Annet vitenskapelig)
    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. 

  • 28.
    Carvalho, Ricardo L.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. 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 universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Lopez, N.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nyambane, Anne
    Nyberg, Gert
    Diaz-Chavez, Rocio
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Household air pollution mitigation with integrated biomass/cookstove strategies in Western Kenya2019Inngår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 131, s. 168-186Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 29.
    Carvalho, Ricardo L.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. 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 universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    García-López, Naxto
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 Kenya2019Inngår i: European Biomass Conference and Exhibition Proceedings, ETA-Florence Renewable Energies , 2019, s. 1536-1542Konferansepaper (Fagfellevurdert)
    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.

  • 30.
    Carvalho, Ricardo
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 Kenya2018Inngår i: / [ed] École Polytechnique Fédérale de Lausanne, UNESCO, Lausanne, 2018Konferansepaper (Annet vitenskapelig)
    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. 

  • 31.
    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 dwellings2018Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 164, s. 140-152Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 32.
    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 universitet, Samhällsvetenskapliga fakulteten, Centrum för miljö- och naturresursekonomi (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 Ecuador2018Inngår i: Energy Strategy Reviews, ISSN 2211-467X, E-ISSN 2211-4688, Vol. 20, s. 35-48Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 33.
    Da Alesandro, Sofia
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Utvinning av snökyla som kylmetod: En förstudie åt Akademiska Hus i Luleå2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    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.

    Fulltekst (pdf)
    fulltext
  • 34.
    Daniel, Petrovic
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    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 poäng / 15 hpOppgave
    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.

  • 35.
    Danielski, Itai
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande, Östersund.
    Nair, Gireesh
    The Department of Ecotechnology and Sustainable Building Engineering, Mid Sweden University, SE-831 25 Östersund, Sweden.
    Fröling, Morgan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för ekoteknik och hållbart byggande, Östersund.
    Heated atrium in multi-storey apartment buildings: a design for better energy efficiency and social interactions2013Inngår i: Passivhus Norden 2013: Papers and Posters, Lågan , 2013, s. 76-87Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The shape factor of a building expresses the ratio between the building’s thermal envelope area and its volume, or alternatively to its useful floor area. Buildings with lower shape factors will have lower heat losses through the thermal envelope and lower specific final energy demand. The shape factor of building could be reduced by a compact building shape design, and by increasing the volume of the building. However, the requirement for indoor natural light put a limit on the size of the building and therefore may limit the value of the shape factor. One possible solution to address this aspect is designing building with a heated atrium.

    An atrium is a large enclosed space within a building, and may have a glazed roof. In a multi-story apartment building an atrium has the potential to increase the social interaction between the residents and, with the right design, at the same time reduce the heating demand of the building due to lower building shape factor. However, the use of atrium in residential buildings in Nordic countries has not yet gained popularity.

    In this paper the impact of the heated atrium building with cylindrical shape design on the specific final energy is investigated by comparing such building design to conventional design buildings with similar floor area. The Nydalahuset project, in city Umeå in the north of Sweden, which is a multistory residential building with a heated atrium, is used as a case study to investigate the affect of the atrium on the social interaction among the building occupants.

    The results show that heated atrium building with cylindrical shape design is a better energy efficient design than the conventional buildings. Such buildings in cold climate could help to reduce the heat losses through the thermal envelope and facilitate to achieve the passive house criteria. Moreover, the Nydalahuset project suggests that the atrium design could improve the social interaction of occupants in residential buildings.

  • 36. Danielski, Itai
    et al.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Joelsson, Anna
    Fröling, Morgan
    Heated atrium in multi-storey apartment buildings, a design with potential to enhance energy efficiency and to facilitate social interactions2016Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 106, s. 352-364Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The design concept of conditioned atria gains increasing popularity in commercial and service buildings all over the world, but is still not a common building design in the residential sector. This study investigates the potential of such design in residential buildings in Nordic climates as means to enhance both energy efficiency as well as social interaction among residents. Energy modelling was used to compare energy efficiency among designs of residential buildings with and without atrium and to identify important design parameters. Social interaction was analysed, based on a survey evaluating the perception of residents living in an existing multi-storey apartment building designed with a heated atrium in the north of Sweden. The results show that heated atrium in Nordic climates have a potential to reduce the total final energy demand while at the same time increase the conditioned space of the building. To positively impact energy efficiency, the atrium should fulfil three requirements: (i) it should be designed to reduce the shape factor for the whole building; (ii) it should have the minimum glazed area that comply with the building requirements concerning natural light and visual comfort; and (iii) adjustable solar shading should be installed in the atrium’s façades to avoid unwanted overheating. The survey results indicate that the additional space created by the atrium has a potential to facilitate and promote social interaction among residents and to increases a sense of neighbourliness and belongingness, which are often discussed as important parameters in relation to social sustainability.

  • 37.
    Dannelind, Filip
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Hydrogen on demand for vessels: Using ammonia for hydrogen storage2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The use of an ammonia and hydrogen mixture in an internal combustion engine has previously been tested.  Limited number of studies have been done on how such a system efficiently can be adopted onboard a vessel and remain competitive to today’s fossil power solutions. A literature study was done to evaluate different aspect of the study such as what concentrations of ammonia and hydrogen that could be usable for an internal combustion engine, what storage tanks that could be used and how the reforming process could be optimized. 

    The study showed that in order for an ammonia and hydrogen on demand power/fuel system to be competitive, focus must be on how to minimize the external thermal input to the system and using a beneficial storage method for the specific vessel. The system has a cold side in which thermal energy is needed and a hot side in which thermal heat needs to be dissipated, comparing option 1-3 shows that managing these two sides of the system greatly increased the efficiency. 

    The study also shows that having an increased hydrogen mixture above   might be deemed unnecessary since it increases the cracker size needed and amount of ammonia tap off from both the main-stream and combustion-stream. Further investigations are needed on how to optimize the schematical design of the system if the temperature of the mixed-stream is deemed to be too high for the engine, this heat could then be utilized in another part of the cold side of the system.

    Fulltekst tilgjengelig fra 2025-05-25 13:00
  • 38. Das, Sujit
    et al.
    Graziano, Diane
    Upadhyayula, Venkata K. K.
    Masanet, Eric
    Riddle, Matthew
    Cresko, Joe
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten. U.S. Department of Energy, Washington, DC 20585, USA.
    Vehicle lightweighting energy use impacts in U.S. light-duty vehicle fleet2016Inngår i: Sustainable Materials and Technologies, ISSN 2214-9937, Vol. 8, s. 5-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, we estimate the potential energy benefits of lightweighting the light-duty vehicle fleet from both vehicle manufacturing and use perspectives using plausible lightweight vehicle designs involving several alternative lightweight materials, low- and high-end estimates of vehicle manufacturing energy, conventional and alternative powertrains, and two different market penetration scenarios for alternative powertrain light-duty vehicles at the fleet level. Cumulative life cycle energy savings (through 2050) across the nine material scenarios based on the conventional powertrain in the U.S. vehicle fleet range from - 29 to 94 billion GJ, with the greatest savings achieved by multi-material vehicles that select different lightweight materials to meet specific design purposes. Lightweighting alternative-powertrain vehicles could produce significant energy savings in the U.S. vehicle fleet, although their improved powertrain efficiencies lessen the energy savings opportunities for lightweighting. A maximum level of cumulative energy savings of lightweighting the U.S. light-duty vehicle through 2050 is estimated to be 66.1billion GJ under the conventional-vehicle dominated business-as-usual penetration scenario. (C) 2016 Elsevier B.V. All rights reserved.

  • 39.
    Egüez, Alejandro
    Umeå universitet, Samhällsvetenskapliga fakulteten, Centrum för miljö- och naturresursekonomi (CERE). Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Nationalekonomi.
    District heating network ownership and prices: The case of an unregulated natural monopoly2021Inngår i: Utilities Policy, ISSN 0957-1787, E-ISSN 1878-4356, Vol. 72, artikkel-id 101252Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The price of district heating in Sweden is unregulated and differs substantially among different networks. This paper investigates if the price variation can partly be explained by whether the district heating network is privately or municipally owned. The empirical analysis is based on district heating prices, ownership status, and network characteristics for the 2012–2017 period. The results show that prices are higher in privately owned district heating networks than in municipally owned networks, especially in the fixed component of the price. Municipal and private providers' divergent objectives may be part of the explanation for these differences.

    Fulltekst (pdf)
    fulltext
  • 40.
    Ekerholm, Helena
    Umeå universitet, Humanistiska fakulteten, Institutionen för idé- och samhällsstudier.
    Cultural meanings of wood gas as automobile fuel in Sweden 1930-19452012Inngår i: Past and present energy societies: How energy connects politics, technologies and cultures / [ed] Nina Möllers & Karin Zachmann, Bielefeld: Transcript Verlag, 2012, s. 223-247Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 41.
    Eklund, Victor
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Utökad nytta av befintligt energilager2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The electrical grid is facing a modernization due to installations of intermittent energy production from wind and solar energy. Energy storage fulfills an important role in this modernization, with potential to store overproduced electricity and use it at a later time. By balancing electricity production and consumption with energy storage, it can provide the grid with stability, increased flexibility and reduce the grid load. An energy storage also makes it possible to keep down the dimensioning at exposed points in the grid, as in connections with high power fast charging stations.

    In the electrical grid of Umea Energy, there is a battery storage of 118 kWh, connected to a fast charging station for electric buses. The high power required by the charging station risked affecting nearby customers, therefore a solution with a battery storage was installed to reduce the impact. With this type of solution, a proportion of power can be retrieved from the grid and the battery storage simultaneously to the fast charging station, which contributes to the power output being smoothed out. However, solutions with battery storage are currently very expensive. To be able to justify an investment of this type of solutions, it is of interest to investigate whether it is possible to increase the utility of a battery storage in order to make the solution more profitable. The purpose of this paper is thus to examine how Umea Energy can increase the utility of a battery storage connected to a charging station and when such a solution may become an economic alternative.

    In this paper, simulation models have been developed in the software MATLAB to investigate whether the battery storage can be used to: 1) reduce power peaks in the neighboring residential area, where the results show that it is possible to reduce a small amount of power in the residential area but that the reduction is limited by how frequent the electric buses charges. 2) Move the load in the grid by letting the battery storage discharge during peak load hours and then recharge it at a later time. The result shows that it may be achievable for a certain time but it could affect the lifetime of the battery storage due to higher depth of discharge (DoD) and 3) Reduce the power during charging of the battery storage. The result indicates that the power can be reduced down to a quarter until affecting the charging schedule of the battery.

    The economic calculations that were carried out compared the profitability of installing a battery storage of 118 kWh to grid investments of 1) two transformers of size 800 kVA each or 2) new grid station incl. two 800 kVA transformers. The result show that there is no economic benefit for Umea Energy to install a battery storage of the investigated type of lithium titanate (LTO) or lithium iron phosphate (LFP) with prices based on 2016 but that it may become profitable with estimated prices from 2030.

    The conclusion that has been drawn from the simulations is that with regard of expanding the utility of a battery storage, there is only a small gain in using the battery storage to reduce power peaks. However, a lower maximum power required from the grid, can advantageously be achieved with a battery storage. In addition, the grid power can be reduced by moving the load during charging of the battery storage between the high peak hours or by reducing the power during the charging of the battery storage. With current battery prices, a battery storage is not considered a profitable investment, and therefore should only be installed to meet specific needs that would otherwise require expensive grid investments. However, the price trend for battery storage looks promising and with prices from forecasts of year 2030 it may become a competitive alternative.

    Fulltekst (pdf)
    fulltext
  • 42.
    Emil, Rönnmark
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Energikartläggning av Kopparhuset i Skellefteå2015Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 43.
    Engman Reed, Martina
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Plan for evaluation of Austin Energy Green Building’s Multifamily Rating Program2014Independent thesis Advanced level (degree of Master (Two Years)), 300 hpOppgave
    Abstract [en]

    Austin Energy Green Building (AEGB) started their multifamily rating program in 1999. It is a green building program where participants can receive different ratings, 1-5 stars, depending on how many requirements the building fulfills. AEGB wants to evaluate the projected energy and demand savings from the multifamily program to be able to report to Austin Energy at the end of the fiscal year.

    Buildings going through the multifamily rating program can either use a prescriptive approach or a performance approach. For the prescriptive approach the savings are evaluated with the help of a deemed savings value. For the performance approach the participant needs to turn in an energy model of the proposed buildings with modeled projected energy and demand savings.

    The purpose of this degree project was to develop a plan for evaluation of the projected savings from the multifamily rating program.  AEGB will need to be able to compare the projected energy and demand savings with the actual energy and demand savings from the buildings that have gone through the program. Focus has been on finding a suitable evaluation approach, based on the available data. Criteria for inclusion were determined. Evaluation of all buildings is not be possible and therefore a sample size needed to be determined for the population. The projected energy savings data was analyzed. A way to account for apartments without full year use data was studied as well as common criteria for uncertainty analysis.

    It was suggested that one year of full energy use data was enough as criterion for buildings to be a part of the population to be evaluated, which gave a population size of 29 buildings.  of the buildings received a 1-3 star rating and they account for about  or  of the projected energy savings. If a simple random sample is used with a confidence level of  and  relative precision the sample will be 21 buildings. If the relative precision is changed to  the sample will contain 11 buildings. Another option is to use stratified random sample, and sample sizes were calculated by star rating and size of the buildings. A number of different ways of accounting for vacant units were found however the latest vacancy rate for multifamily buildings in Austin was . This corresponds to about  in lost projected energy savings for the buildings that have gone through AEGB’s multifamily program. Lastly, post occupancy evaluation (POE) will be recommended for this evaluation effort of AEGB’s multifamily program.

    Fulltekst (pdf)
    Plan for evaluation of Austin Energy Green Building’s Multifamily Rating Program
  • 44.
    Eriksson, Henrik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Tillvaratagande av förlustvärme från frekvensomformarstationer2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    För effektmatning av den elektrifierade järnvägen krävs att spänningens frekvens omformas från kraftnätets frekvens på 50 Hz till 16,7 Hz. Detta sker i dag med två olika metoder. En metod där frekvensen omformas på mekanisk väg då en motor på gemensam axel driver en generator som genererar elkraft av rätt frekvens, detta kallas för en roterande frekvensomformare. Den andra metoden ändrar spänningens frekvens med hjälp av kraftelektronik, detta kallas för en statisk frekvensomformare. Gemensamt för båda dessa metoder är att de har värmeförluster. För de roterande omformaraggregaten så är förlustvärmen till stor del luftburen medan de statiska frekvensomformarna har både vätske- och luftkylning. I många fall ser det i dagsläget ut så att förlusterna kyls bort mot omgivningen.

    Syftet med detta arbete är att bestämma huruvida dessa värmeförluster kan nyttjas för uppvärmning av stationsbyggnaderna där omformaraggregaten finns på ett lönsamt vis.

    I arbetet har två frekvensomformarstationer undersökts. En station med enbart roterande frekvensomformare i Gällivare samt en station med enbart statiska frekvensomformare i Boden. Båda omformarstationerna har idag energisystem för uppvärmning baserade på direktverkande el.

    I simuleringsmodeller och mätningar har de båda omformarstationernas energibehov för uppvärmning fastställts. För Gällivare omformarstation rör det sig om en specifik energiförbrukning för uppvärmning motsvarande ca 300 kWh/m2. För Bodens omformarstation är den sammantagna specifika energianvändningen 204 kWh/m2.

    Genom ytterligare mätningar har delar av frekvensomformaraggregatens effektförluster fastställts och analyserats med hänsyn till storlek och tidsvariationer. Rapporten fastslår att förlustvärmen från luftkylningen av de roterande omformarna räcker för att täcka stationens uppvärmningsbehov. Rapporten fastslår även att tomgångsförlusterna från ett omformaraggregat räcker för att förse omformarstationen i Boden med tillräcklig värmeenergi för uppvärmning. De båda omformarstationernas förlusteffekter uppvisade även en regelbundenhet i effektflödet vilket möjliggör för en värmeåtervinningslösning utan behov av ackumulator.

    För Gällivares omformarstation har ett utformat förslag på en teknisk lösning för uppvärmning av omformarstationen med förlustvärme från frekvensomformaraggregaten presenterats. Detta består av ett projekterat och dimensionerat överluftssystem för uppvärmning av byggnaden med den uppvärmda luften från frekvensomformaraggregatens kylsystem. Luftflödet för att möta det simulerade effektbehovet för uppvärmning uppgår i ca 9,5 l/(s ∙m2), ett flöde som kan orsaka problem med luftdrag och ljudalstring som gör arbetsmiljön dålig. Då omformarstationen i normala fall är obemannad föreslogs en strömbrytare som inaktiverar överluftssystemet vid besök på omformarstationen av underhållspersonal. En ekonomisk sammanställning baserad på LCC (Life cycle cost) har fastställt att en investering kan vara lönsam inom 5 år. För Bodens omformarstation har ingen teknisk lösning presenterats.

    Fulltekst (pdf)
    Tillvaratagande av förlustvärme från frekvensomformarstationer
  • 45.
    Essalhi, Mohamed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Department of Structure of Matter, Thermal Physics and Electronics, Faculty of Physics, University Complutense of Madrid, Avda. Madrid, Spain.
    Khayet, Mohamed
    Ismail, Norafiqah
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sundman, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tavajohi Hassan Kiadeh, Naser
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Improvement of nanostructured electrospun membranes for desalination by membrane distillation technology2021Inngår i: Desalination, ISSN 0011-9164, E-ISSN 1873-4464, Vol. 510, artikkel-id 115086Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A systematic study is carried out to determine the optimum electrospinning preparation condition to prepare an adequate electrospun nanofibrous membrane (ENM) for direct contact membrane distillation (DCMD). A structural properties investigation of ENM was carried out because of the significant impact of its architectural structure, nanofiber diameter, inter-fiber space and ENM thickness, on DCMD performance. The morphology, hydrophobicity, mechanical properties, crystallinity and DCMD desalination were investigated. A long-term DCMD experiment (100h) was carried out using 30 g/L NaCl aqueous solution, both in the feed and permeate side of the optimum ENM membrane to evaluate its potential to produce drinkable water in case of lack of distilled water, for instance in a remote area, emergency situation, and/or portable system. In this case, drinkable water could be produced after 28 h with a permeate flux of 57.5 kg/m2.h and a salt rejection factor greater than 99.9%. Another long-term DCMD experiment (65 h) was conducted using 30 g/L NaCl aquesous solution as feed but at a higher temperature and distilled water as permeate to evaluate the desalination stability, wettability and scaling of the optimum ENM. A permeate flux of 58.5 kg/m2.h was obtained with a salt rejection factor greater than 99.9%.

  • 46.
    Essalhi, Mohamed
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Department of Structure of Matter, Thermal Physics and Electronics, Faculty of Physics, University Complutense of Madrid, Avda. Complutense s/n, Madrid, Spain.
    Khayet, Mohamed
    Department of Structure of Matter, Thermal Physics and Electronics, Faculty of Physics, University Complutense of Madrid, Avda. Complutense s/n, Madrid, Spain; Madrid Institute for Advanced Studies of Water (IMDEA Water Institute), Calle Punto Net N° 4, Alcalá de Henares, Madrid, Spain.
    Tesfalidet, Solomon
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Alsultan, Mohammed
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tavajohi Hassan Kiadeh, Naser
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Desalination by direct contact membrane distillation using mixed matrix electrospun nanofibrous membranes with carbon-based nanofillers: a strategic improvement2021Inngår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 426, artikkel-id 131316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Robust hydrophobic and superhydrophobic mixed matrix electrospun nanofibrous membranes (MM-ENMs) have been prepared from low- and high- molecular weight polyvinylidene fluoride with either multi-walled carbon nanotubes or graphene oxide nanofillers (0.05–0.5 wt%). The polymer solutions' properties, including their electrical conductivity, viscosity, and surface tension, were determined and used to guide the design of single-, dual-, and triple-layered MM-ENMs combining layers with different hydrophobic character. All MM-ENMs were subsequently prepared and characterized in terms of their morphology, hydrophobicity, mechanical properties, and direct contact membrane distillation (DCMD) performance. A thinner hydrophobic layer with a thicker hydrophilic support layer in dual-layered MM-ENMs reduced water vapor transport resistance and improved DCMD performance relative to single-layer MM-ENMs. Conversely, placing an intermediate hydrophilic layer between two hydrophobic layers in triple-layered MM-ENMs promoted water condensation (water pocket formation) and thus reduced DCMD performance. Over 10 h DCMD, the best-performing dual-layered MM-ENM allowed ultra-high permeate fluxes of up to 74.7 kg/m2 h while maintaining a stable permeate electrical conductivity of around 7.63 μS/cm and a salt (NaCl) rejection factor of up to 99.995% when operated with a feed temperature of 80°C, a permeate temperature of 20°C, and a feed solution containing NaCl at a concentration of 30 g/L.

    Fulltekst (pdf)
    fulltext
  • 47.
    Fagernäs, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    The Energy Savings Potential of a Heat Recovery Unit and Demand Controlled Ventilation in an Office Building2021Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The building sector is responsible for approximately 40 % of the total energy usage in Sweden. In office buildings the heating, ventilation and air conditioning system can account for up to 55 % of the energy usage. In order to reduce the energy usage of the heating, ventilation and air conditioning system different control methods are often used. One of these control methods is demand controlled ventilation, where the ventilation system is controlled with regard to occupancy with the help of motion and/or CO2 sensors.

    The aim of this thesis was to determine the energy savings potential of a heat recovery unit as well as demand controlled ventilation in an office building. The effect of longer intervals between sensor control signals to the ventilation system was also investigated. This is done by creating schedules, gathered from actual building occupancy, that are being used to control the occupancy and ventilation in a building model in the building performance simulation software IDA ICE. As a reference building, the fifth floor of the LU1 section of the natural science building at Umeå University is used. The reference building consists of 40 offices for which the occupancies are known.

    The average occupancy for all the offices combined throughout the investigated time period is determined to be 34.8 %. The results from the simulations indicate that an energy savings potential of 52.98 % can be achieved by a heat recovery unit with an efficiency of 80 % or 95 %, when compared to not having a heat recovery unit. When implementing demand controlled ventilation an energy savings potential of 2.8-11.0 % can be achieved, with the energy savings potential decreasing when the efficiency of the heat recovery unit increases. Finally, it is shown that longer intervals between sensor control signals to the ventilation system leads to a small increase in energy usage and poorer indoor air quality.

    Fulltekst (pdf)
    fulltext
  • 48.
    Fogelström, Frej
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Danielski, Itai
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Truong, Nguyen Le
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Nair, Gireesh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    A review of possibilities and challenges of pit thermal energy storages in Swedish district heating networks2024Inngår i: ISEC 2024: 3rd International Sustainable Energy Conference, AEE – Institute for Sustainable Technologies , 2024Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The use of pit thermal energy storages (PTES) enables higher solar fraction in district heating networks by counteracting the mismatch between heat demand and production in solar district heating (SDH) installations. Capital costs linked to land areas with site-specific geological conditions are the deciding factors for PTES constructions. This study investigates non-technical and technical factors for the implementation of PTES in Swedish district heating networks. Having several SDH and PTES installations in operation the country of Denmark is used as a reference. This study, based on literature review, discusses the drivers and challenges for the use of PTES in district heating networks.

    Fulltekst (pdf)
    fulltext
  • 49.
    Fors, Jonna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Utvärdering av vädersäkring på mellanspänningsnät: Analys utifrån felorsak, terräng och ledningstyp2022Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Dagens IT-samhälle bygger på många viktiga funktioner som kräver en säker elförsörjning. Snö och blåst har historiskt sett orsakat många och långa avbrott hos elanvändare runt om i landet vilket har lett till nya lagar kring ersättning vid elavbrott. Det har inneburit att flera elnätsbolag valt att på mellanspänningsnätet byta ledningar i luft till markkabel. 

     

    Målet med detta arbete var att ta fram samband mellan antalet avbrott och hur stor del av ledningen som går genom skog, samt se om det finns variationer mellan nätområden och vilka felorsaker som tas hänsyn till. Därefter skulle medelavbrottstiden för luftledning och markkabel beräknas och jämföras. Detta gjordes med hjälp av felstatistiken på Ellevios mellanspänningsnät under 2018 - 2020 samt information om linjernas uppbyggnad. I statistiken gick det inte att urskilja var på linjen felet inträffat. 

     

    Sambanden visar att träd på ledning tillsammans med vegetation är de felorsaker som påverkas mest av att luftledningen går i skog. För övriga väderrelaterade felorsaker finns inget samband utan antalet avbrott ligger konstant kring 1-3 avbrott per 100 km luftledning och år. Beräkningarna visar att den omfattande kablifieringen har resulterat i klart lägre kundavbrottstid. Att gå från luftledning enbart i skog till markkabel sänker i snitt kundavbrottstiden med 92 %, 41 till 3 timmar, per 100 km ledning och år. Det innebär en genomsnittlig SAIDI-minskning på 0,8 minuter. Västkusten är det område där kablifiering skulle medföra störst sänkning av kundavbrottstiden. Att välja trädsäkra ledningsgator istället för ledning enbart i skog skulle innebära en minskning av kundavbrottstiden med 74 %. 

     

    Felfrekvensen på individuella linjer varierar kraftigt och i resultatet är standardavvikelsen ibland är större än gruppens medelvärde. Resultaten ovan har därför ingen statistiskt signifikans. Om man i framtiden skulle rapportera var på linjen felet inträffar och på det sättet kunna koppla felet till luftledning, hängkabel eller markkabel samt skog eller inte skog skulle det gissningsvis gå att dra statistiskt signifikanta slutsatser. 

    Fulltekst (pdf)
    Utvärdering av vädersäkring på mellanspänningsnät
  • 50.
    Fossum, Heidi
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Coordinated freight logistics in existing city districts- Evaluation of methods for calculating energy and environmental effects2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Norra Djurgårdsstaden is the largest ongoing construction project in Sweden and is planned to be completed in 2030. The city district is situated in north-eastern Stockholm, in a former industrial area where approximately 12 000 new homes and 35 000 workplaces are planned. The city district focuses strongly on reducing energy consumption and the negative impacts on the environment. One idea for realizing this goal is to implement coordinated freight logistics. This can be accomplished by building a consolidation centre where goods from different logistics companies and freight carriers can be loaded together on the same delivery vehicles and then be delivered in the same area in Norra Djurgårdsstaden.

     

    The purpose of this master thesis is to evaluate five earlier evaluation reports on consolidation centres. Based on these evaluation reports and other relevant literature, it is recommended how a coordinated freight logistic project should be organized in Norra Djurgårdsstaden and how the impact on the environment and energy consumption should be calculated. The evaluation reports are from the logistic centre in the Old Town of Stockholm, the pilot project Samlic in Linköping, the urban consolidation centre in Norwich, the micro-consolidation centre in London and several urban logistic practices in Utrecht. A thorough comparative analysis of the five different evaluation reports has looked at the initiators and the stakeholders, the delivery situation before and after the implementation of the consolidation centre as well as done a deeper evaluation analysis of all the evaluation reports. The comparative analysis showed that the consolidation centres have had a positive effect on decreasing the number of delivery vehicles in the city district and thereby reducing the emissions and the energy consumption from the delivery vehicles.

     

    Based on the comparative analysis and other literature it is suggested that the initiative to build a consolidation centre in Norra Djurgårdsstaden has to come from the City of Stockholm. The stakeholders should be the City of Stockholm, logistics companies, freight companies, the different businesses in the area and the Ports of Stockholm. To encourage even more businesses to have deliveries from the consolidation centre and get more environmentally friendly delivery vehicles in the city district it might be necessary to use several management control instruments. Examples of control instruments are environmental zones, time windows and implement different restrictions on the delivery vehicles. It is essential to gather information about the delivery vehicles in the city district to estimate emissions and the energy consumption. The collection of data from the delivery vehicles can be gathered from consignment notes, driver notes, invoice data or statistics of the number of vehicles that have delivered goods in the city centre from freight and logistics companies. Then the delivery vehicles impact on energy consumption and the environment can be estimated with the computer tool Network of transports and environment (NTM-method).

     

    Fulltekst (pdf)
    Examensarbete Heidi Fossum
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