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  • 51.
    Eriksson, Ola
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Nuclear power and resource efficiency-A proposal for a revised primary energy factor2017In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 9, no 6, article id 1063Article in journal (Refereed)
    Abstract [en]

    Measuring resource efficiency can be achieved using different methods, of which primary energy demand is commonly used. The primary energy factor (PEF) is a figure describing how much energy from primary resources is being used per unit of energy delivered. The PEF for nuclear power is typically 3, which refers to thermal energy released from fission in relation to electricity generated. Fuel losses are not accounted for. However; nuclear waste represents an energy loss, as current plans for nuclear waste management mostly include final disposal. Based on a literature review and mathematical calculations of the power-to-fuel ratio for nuclear power, PEF values for the open nuclear fuel cycle (NFC) option of nuclear power and different power mixes are calculated. These calculations indicate that a more correct PEF for nuclear power would be 60 (range 32-88); for electricity in Sweden (41% nuclear power) PEF would change from 1.8 to 25.5, and the average PEF for electricity in the European Union (EU) would change from 2.5 to 18. The results illustrate the poor resource efficiency of nuclear power, which paves the way for the fourth generation of nuclear power and illustrates the policy implication of using PEFs which are inconsistent with current waste management plans.

  • 52.
    Eriksson, Ola
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Perspektiv på biogas: En antologi om biogas som drivmedel med fokus på teknik, miljöpåverkan och samhällsnytta2013Report (Other academic)
    Abstract [sv]

    På uppdrag av utvecklingsprojektet BiogasMitt har Högskolan i Gävle sammanställt denna antologi om biogas. Målgruppen är studenter som läser energi- och miljöteknik på högskolenivå, men den kan också användas i uppdragsutbildning för tjänstemän och politiker som vill veta mer om biogas som samhällsföreteelse.

    Antologin är sammansatt av följande delar:

    Del 1 En kunskapssammanställning om biogas. Denna del är en bearbetad version av en större systemanalys för Gästrikeregionen som Högskolan tagit fram med stöd av forskningsstiftelsen Gästrikeregionens Miljö. I bearbetningen har vissa delar valts och kompletterats med ny text. Studien i sin helhet är publicerad på BiogasMitts hemsida och skriven av Ola Eriksson och Teresa Hermansson. Texten publicerad här är bearbetad av Ola Eriksson.

    Del 2 Varför kommunerna är viktiga för framväxten av biogas. Denna del baseras på en presentation framförd vid seminariet ”LNG och LBG i Gävleborg och Dalarna?” som hölls i Stora gasklockan i Gävle torsdagen den 29 september av Ola Eriksson. Föredraget har dokumenterats i löpande text och anpassats till antologins format av Ola Eriksson.

    Del 3 Environmental technology assessment of natural gas compared to biogas. Denna del är skriven på engelska och tidigare publicerad i boken “Natural Gas” editedby Primoz Potocnik. Författare är Ola Eriksson.

    Del 4 Improvements in environmental performance of biogas production from municipal solid waste and sewage sludge. Denna del är skriven på engelska och tidigare publicerad som ett bidrag till konferensen World Renewable Energy Congresss om hölls i Linköping 8-12 maj 2011. Huvudförfattare är Ola Eriksson. Medförfattare är Mattias Bisaillon, Mårten Haraldsson och Johan Sundberg.

    Del 5 Energianalys av Svensk Växtkrafts biogasanläggning i Västerås. Denna del återger i sin helhet ett examensarbete som handletts av Ola Eriksson. Författare är Jenny Liljestam Cerruto.

  • 53.
    Eriksson, Ola
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering. Profu AB, Mölndal, Sweden.
    Bisaillon, Mattias
    Profu AB, Mölndal, Sweden.
    Haraldsson, Mårten
    Profu AB, Mölndal, Sweden.
    Sundberg, Johan
    Profu AB, Mölndal, Sweden.
    Enhancement of biogas production from food waste and sewage sludge: environmental and economic life cycle performance2016In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 175, p. 33-39Article in journal (Refereed)
    Abstract [en]

    Management of municipal solid waste is an efficient method to increase resource efficiency, as well as to replace fossil fuels with renewable energy sources due to that (1) waste to a large extent is renewable as it consists of food waste, paper, wood etc. and (2) when energy and materials are recovered from waste treatment, fossil fuels can be substituted. In this paper results from a comprehensive system study of future biological treatment of readily degradable waste in two Swedish regions are presented. Different collection and separation systems for food waste in households have been applied as well as technical improvements of the biogas process as to reduce environmental impact. The results show that central sorting of a mixed fraction into recyclables, combustibles, biowaste and inert is a competitive option compared to source separation. Use of pellets is beneficial compared to direct spreading as fertiliser. Fuel pellets seem to be the most favourable option, which to a large extent depends on the circumstances in the energy system. Separation and utilisation of nitrogen in the wet part of the digestion residue is made possible with a number of technologies which decreases environmental impact drastically, however to a substantial cost in some cases.

  • 54.
    Eriksson, Ola
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Hermansson, Teresa
    Avfallsprevention i stålindustrin: Exempel från Sandvik Materials Technology2013Report (Other academic)
    Abstract [sv]

    I samband med extern granskning av forskningsprogrammet Hållbar avfallshantering kom det fram att mer fokus borde läggas på att beskriva åtgärder som träffar högt upp i avfallshierarkin, d.v.s. att undvika att avfall uppkommer, återanvändning och återvinning. Denna rapport utgår från detta önskemål och beskriver hur återvinning och prevention av interna restproduktflöden inom stålindustrin kan gå till och ger exempel från Sandvik Materials Technology. Underlag till denna studie är ett studiebesök på SMT i Sandviken, samtal med Lotta Lind som arbetade som restproduktingenjör och granskning av textdokument som miljörapport och ett tidigare utfört examensarbete. Rapporten är en syntes utifrån dessa källor.

    I rapporten redovisas vilka problem och lösningar som finns för rent metallavfall som skrot, spånor och stofter, metalloxider som gasreningstoft och glödskal, metallhydroxidslam, slagger och blyhaltigt avfall. Det rena metallavfallet återanvänds redan till 100 % i processen, ofta internt men ibland av extern aktör. För metalloxider i form av glödskal finns det en fungerande återvinningsprocess utan för SMT, men planer finns på att göra investeringar för att SMT själva skall kunna ta hand om avfallet. Metallhydroxidslam deponeras men det finns långt gångna planer för hur processer och rening skall ändras så att slammet skall kunna återvinnas. Även för slagg, som är det till mängden mest betydelsefulla avfallet, finns planer för hur den nuvarande deponeringen skall kunna minskas drastiskt till förmån för återbruk och återvinning av materialet som exempelvis konstruktionsmaterial på deponier. Blyhaltiga avfall har visat sig kunna värmebehandlas så att blyet kan återvinnas. Resultatet blir att värdefullt och miljöfarligt bly recirkuleras inom SMT och de rester som blir kvar skulle kunna klassas om till icke-farligt.

    Samtliga exempel på avfallsprevention bygger på tankar om ökad recirkulering, extern avsättning för uppkomna restprodukter och minskad mängd restprodukt per mängd prima vara producerad. Förutom betydande miljömässiga fördelar uppvisar många av förändringarna goda ekonomiska resultat efter relativt kort tid.

  • 55.
    Eriksson, Ola
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Hermansson, Teresa
    Biogas i Gästrikeregionen - BiG: En systemanalys2013Report (Other academic)
    Abstract [sv]

    I södra Sverige finns en tämligen väl utbyggd infrastruktur för biogas (Gasföreningen, 2009). Totalt finns över 92 tankställen för personbilar och 30 tankställen för tunga fordon i landet. Gävleborgs län kallas ibland för ”stopplänet” eftersom det finns, eller kommer snart att finnas, fordonsgas såväl söderut, norrut som västerut. Förutom en lokal användning av biogas i regionen så passerar en betydande del av de bilburna semesterfirarna vårt län på väg till fjällen eller sommarvisten. En del av dessa vill kunna tanka biogas här.

    Undersökningar utförda på uppdrag av Gästrike Avfallshantering AB 1999 gav vid handen att det fanns för lite slakteriavfall för att göra rötning lönsamt. Några år senare ställdes frågan på nytt om vilken sorts biologisk behandling man borde ha och då valdes kompostering framför rötning p.g.a. teknikkrångel på andra ställen. Dessutom visade undersökningarna inte på någon större efterfrågan på biogas.

    Målet har varit att i en systemanalys ge en samlad bild av förutsättningarna (fysiska och icke-fysiska) för etablering av biogas i Gästrikeregionen. Systemanalysen har utförts i flera delar:

    1. Aktörsanalys
    2. Teknik- och omvärldsbevakning
    3. SWOT-analys
    4. Teknisk systemanalys

    Resultaten visar att det i regionen, eventuellt med stöd av omgivande regioner, finns möjligheter att röta avfallet. Anläggningarna är tekniskt sett bättre idag, det borde gå att få tag på tillräckligt med substrat som ger tillräckligt med gas och det finns efterfrågan på gasen.

    För att detta skall ske så måste kommunerna (förvaltningar, bolag, kommunalförbund) jobba samlat och klara av att hantera alla olika brickor i biogasspelet. Nästa lika viktiga är lantbrukarna som skulle kunna få fram stora mängder substrat samtidigt som de är viktiga för återförningen av rötrest till åkermark. Dessvärre noterar vi vissa samarbetssvårigheter mellan lantbrukare och kommun.

    Vad krävs då för att det skall bli någon biogasproduktion i regionen? Listan över kriterier som behöver vara uppfyllda för att biogasproduktion skall komma till stånd kan göras oändlig men vi har i denna studie försökt vaska fram några huvuddrag. Vi har redan betonat vikten av regional samordning inom kommunsfären och i synnerhet kommuner visavi lantbruket. Det handlar om förtroendeskapande åtgärder och det handlar om letter-of-intent och avtal för att säkra substratleveranser och avsättning för rötrest och biogas. Priset på fossil energi liksom den nationella energi- och miljöpolitiken påverkar på mer än ett sätt hur snabbt utvecklingen sker. Lokaliseringsfrågan är också en nöt att knäcka där vi i denna studie visat att det finns för- och nackdelar med både Forsbacka och Duvbacken. Det som avgör det hela är ifall det går att räkna hem en satsning ekonomiskt. Affärsmässigheten bedöms av Gävle Energi i en separat studie (dock med andra geografiska gränser).

  • 56.
    Eriksson, Ola
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Hermansson, Teresa
    Hållbar konsumtion och hållbar avfallshantering - vad är det?: Diskussion kring dagsläget och framtiden : Dokumentation från seminarium och workshop på Högskolan i Gävle den 18 mars 20102013Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    I samarbete med forskare inom forskningsprogrammet Hållbar avfallshantering inbjöd forskningsstiftelsen Gästrikeregionens Miljö till en heldag om avfall och konsumtion. Inbjudan riktades till kommuner, länsstyrelser, företag och organisationer i Gävleborg och Dalarna. Under förmiddagen hölls ett antal olika föredrag och presentationer med en avslutande paneldebatt. Eftermiddagen bjöd på en workshop med gruppvisa diskussioner kring vilka styrmedel som skulle fungera regionalt och lokalt samt kring avfallsminimering (avfallsprevention). Forskningsseminariet ägde rum torsdagen den 18 mars på Högskolan i Gävle.

    Syftet med seminariet var att sprida kunskap om pågående forskning till branschfolk samt att fånga upp vilka styrmedel som kan vara aktuella på lokal respektive regional nivå, men även diskutera mekanismer för att åstadkomma avfallsminimering. Dokumentationen av seminariet följer programmet.

  • 57.
    Eriksson, Ola
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Hermansson, Teresa
    Regional avfallshantering: Slutrapport från projekt finansierat av Forskningsstiftelsen Gästrikeregionens Miljö2013Report (Other academic)
    Abstract [sv]

    Varje svensk kommun är skyldig att upprätta en avfallsplan som redogör för hur avfallet som uppkommer i kommunen skall omhändertas. Den nuvarande avfallsplanen för Gästrikeregionen (som omfattar kommunerna Gävle, Sandviken, Hofors, Ockelbo och Älvkarleby) gäller för perioden 2011-2020. Avfallsplanen arbetades fram under 2009-2010 med Högskolan i Gävle som deltagare. I anslutning till detta utvecklingsarbete har högskolan arbetat med ett antal frågeställningar med koppling till avfallsplanen:

    • Miljöbedömning av avfallsplanen
    • Förebyggande av avfall
    • Människors beteende avseende sortering
    • Fastighetsnära insamling
    • Minskning av fossila koldioxidutsläpp
    • Energiberäkningar för material som lämnas via återvinningscentraler
    • Förutsättningar för och konsekvenser av en övergång från kompostering till rötning av matavfallet

    Projektet har pågått under 2009-2010 med Ola Norrman Eriksson och Teresa Hermansson som utförare. Utredningen har genomförts genom intervjuer, litteraturstudier, personlig kommunikation och ett publikt seminarium.

    Resultaten visar att en miljöbedömning av en avfallsplan är en komplex och omfattande uppgift. Bedömningen bör göras utifrån nuläget och beskriva de framtida konsekvenserna av de mål och åtgärder som planen föreskriver. Projektet har genom ett välbesökt seminarium också visat att samhället ännu inte funnit formerna för att arbeta med förebyggande åtgärder. Att på bästa sätt hantera ett uppkommet avfall är en sak, att förhindra dess uppkomst en annan. För produktionsavfall finns det goda exempel, medan det för konsumtionsavfall är betydligt svårare.

    Beteendevetenskapliga studier inom området visar att det är en utmaning att utforma information på ett sådant sätt att den når alla typer av mottagare och får dessa att agera i enlighet med infor-mationen. Vi människor tänker mer i termer av att återanvända och sortera olika slags material, snarare än att fundera på vad som är förpackning eller ej. Sortering av avfall är något folk i regel förväntar sig ska vara enkelt att utföra och det måste vara bekvämt. Införande av fastighetsnära insamling är ett sätt att underlätta och i de kommuner där det införts har mängderna återvinningsbart material ökat kraftigt samtidigt som mängderna brännbart restavfall minskat markant. Ett ökat insamlingsarbete för kommunen skall vägas mot minskat bilåkande till återvinningsstationer och återvinningscentraler samt minskade transporter till förbränning och därmed associerade utsläpp. Då återvinning generellt är bättre för miljön än förbränning uppstår vinster även i behandlingsledet. Studien visar också att avfall kan transporteras långa sträckor till återvinningscentraler utan att på något sätt hota den miljövinst som görs genom att avfallet materialåtervinns eller energiutvinns.

    Vid en övergång från kompostering till rötning tillkommer nya bioråvaror och denna studie visar på några av de faktorer man måste ta hänsyn till vid kapacitetsberäkningar. Detta är av yttersta vikt då mängder och gaspotentialer ligger som grund för de investeringskalkyler som upprättas och kan vara avgörande för om en biogasanläggning alls byggs. Men det är inte bara biogas som produceras utan även en biogödsel som bör komma in i kretsloppet. Studien redovisar svar från lantbrukare kring frågor om leverans av gödsel och användning av biogödsel liksom intresset för delägarskap i en framtida anläggning. Studien ger också några svar på frågor kring hur sorteringsinformationen bör förändras.

  • 58.
    Eriksson, Ola
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Jönsson, Johanna
    Svensk avfallshantering: Diskussion kring dagsläget och branschens forskningsbehov : Dokumentation från workshop på Högbo bruk 19 Januari 20052013Report (Other academic)
    Abstract [sv]

    Stiftelsen Gästrikeregionens Miljö inbjöd i samarbete med Högskolan i Gävle till en eftermiddag och kväll med workshop-diskussioner kring var avfallshanteringen i Sverige står idag och vilka frågor som behöver få en lösning framöver. Workshopen ägde rum onsdag 19 januari 2005 kl. 12-21 på Högbo Bruk i Sandviken.

    Syftet med workshopen var att sprida kunskap om pågående forskning (frågeställningar, kompetenser och idéer för framtiden) till branschfolk samt att tillsammans lokalisera vilka frågor som engagerar mest och där vi kan göra en gemensam insats. I konkreta termer vill stiftelsen hitta kompletterande forskning till den verksamhet som redan bedrivs vid Högskolan i Gävle och som i enlighet med Stiftelsens och Gästrike Återvinnares önskemål är inriktad på människors och företags attityder, kunskaper och göranden.

    Dokumentationen följer workshopens program så som det genomfördes. Bilagorna är upplagda enligt följande:

    Bilaga 1 är en kopia av programmet.

    Bilaga 2-8 innehåller det underlag som användes vid de olika presentationerna.

    Bilaga 9 innehåller en förteckning över de personer som deltog på workshopen.

    Bilaga 10 innehåller det förslag som Leif Magnusson lade fram angående grundandet av Föreningen Avfallsforskning.

  • 59. Eriksson, Ola
    et al.
    Karlsson, Björn
    Thygesen, Richard
    Regelstyrd energi- och miljövärdering av byggnader2017Report (Other academic)
  • 60.
    Eriksson, Ola
    et al.
    Industrial Ecology, Dept. of Chemical Technology and Engineering, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Olofsson, Mattias
    Energy Systems Technology Division, Chalmers University of Technology, Göteborg, Sweden.
    Ekvall, Tomas
    Energy Systems Technology Division, Chalmers University of Technology, Göteborg, Sweden.
    How model-based systems analysis can be improved for waste management planning2003In: Waste Management & Research, ISSN 0734-242X, E-ISSN 1096-3669, Vol. 21, no 6, p. 488-500Article in journal (Refereed)
    Abstract [en]

    Waste management models have been developed worldwide since the late 1960s. The overall aim of the models is to assist decision makers who are facing a complex task in order to handle waste in a cost-efficient and environmentally sound way. International research publications regarding waste management models point out the major benefits to be their capacity to deal with complexity and uncertainty and of finding benefits of co-operation and handling different goals. Such models have been developed and used successfully in Swedish research projects since the beginning of the 1990s, but the current situation is that such models are rarely requested for waste management planning in the country. Based on case studies (with the waste management models MIMES/Waste and ORWARE) in the Swedish municipality of Jönköping and a follow-up study, the paper discusses and draws conclusions on how to improve and increase the use of models to better correspond to the needs of decision makers involved in waste management planning.

  • 61.
    Eriksson, Ola
    et al.
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Svanblom, Leif
    Avdelningen för industriellt miljöskydd, KTH, Stockholm.
    Framtida behandling av lättnedbrytbart organiskt avfall i Jönköpings kommun: En systemstudie av effekter på miljö, energi och ekonomi2000Report (Other academic)
    Abstract [sv]

    I denna studie utförd av KTH - Industriellt Miljöskydd på uppdrag av Jönköpings kommun har en jämförelse av rötning och förbränning av lättnedbrytbart organiskt avfall genomförts. Jämförelsen omfattar effekter på miljö, energi och ekonomi för insamling, transport och behandling av avfallet samt omhändertagande av restprodukter.

    Med hjälp av datormodellen ORWARE har, efter genomförd inventering, ett antal simuleringar av Jönköpings tänkta framtida avfallsbehandling gjorts. De simulerade scenarierna har arbetats fram i samarbete mellan Tekniska kontoret på Jönköpings Kommun och Jönköpings Energi AB. Effekter på miljön i form av global uppvärmning, övergödning, försurning samt bildande av fotokemiska oxidanter har kvantifierats och uttag av energiresurser samt företags- och miljöekonomiska kostnader beräknats.

    Studien omfattar allt lättnedbrytbart organiskt avfall i Jönköpings län och tar inte hänsyn till hur stora mängder som i realiteten är tillgängliga för organisk avfallsbehandling. En kommande förbränningsanläggning förbränner inte endast lättnedbrytbart organiskt avfall. Därför har även blandat hushållsavfall tagits med för att kompensera förbränningsanläggningen då det lättnedbrytbara organiska avfallet rötas.

    Studien visar att det i dagens situation inte förekommer någon konkurrens mellan rötning och förbränning av det lättnedbrytbara organiska avfallet. Alla insatser som kan göras för att undvika deponering av avfallet (som är det vanligaste idag) bör genomföras. En kombination av rötning av det lättnedbrytbara organiska avfallet (istället för förbränning) och förbränning av det blandade avfallet (istället för deponering) har en positiv inverkan på global uppvärmning, försurning, energiåtgång och kostnader. Biologisk behandling ger försämringar för övergödning relativt förbränning med nuvarande jordbruksteknik.

    I en framtid då rötning konkurrerar med förbränning finns det både för- och nackdelar med båda alternativen. Miljöekonomiskt och även energimässigt är det fördelaktigare att förbränna avfallet medan det är obetydliga skillnader för global uppvärmning och försurning. Även i framtiden är det ogynnsamt att röta ur övergödningssynpunkt.

  • 62.
    Fredlund, Thomas
    et al.
    University of Gävle, Department of Technology and Built Environment.
    Shoshtari, Salahedin
    University of Gävle, Department of Technology and Built Environment.
    Energy flow survey of Ljusdals municipality2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The aim of this project is to make an energy flow survey of Ljusdal’s municipality. The reason for the energy flow survey is to discover possibilities to utilize and refine the energy resources locally, and use the information from this survey as a base for further discussions about the energy situation in Ljusdal’s municipality. As it is today the raw material is transported to other municipalities for processing and then bought back, e.g. biomass is transported to other municipalities where they make pellets which are sold back to consumers in Ljusdal’s municipality. A local upgrading of the raw material will probably create more job opportunities in the municipality and it will probably also lead to a higher profit than just selling the raw material. The target groups for this study are the local (and regional) politicians and entrepreneurs, primarily in Ljusdal but also in other similar municipalities. Mainly bioenergy is handled in this thesis. Other energy sources e.g. hydroelectricity is handled just briefly, flows and use of electricity are described briefly for different parts of the municipality and types of consumers. To perform the energy flow survey, information about now used, and possible future, energy resources was collected in order to find out the energy quantities used per year, for different users, and the energy flows. Unexploited energy sources, and energy sources that have the potential to be increased, like forest and arable land was also included. Investigations about the wind potential are also carried out. The energy use of the consumers, divided into energy carriers, is mapped. Larger companies and institutions, particularly those with energy related business are asked about their future plans. Energy suppliers are also asked where they buy and sell energy in order to make an energy flow survey. The energy needs for different types of buildings were also considered in this energy flow survey. In order to do that, information about the numbers of buildings in the municipality and also the average energy usage, for different types of buildings e.g. apartments and single family houses, are collected from different sources. The flows of bioenergy across the municipality border are also investigated in order to be able to see where it comes from and where it goes. Nearby municipalities, projects nearby Ljusdal’s municipality, that may have an impact in the field of energy in Ljusdal’s municipality are also briefly handled. The energy flows, in and out of the municipality, were put into maps from the municipality’s Geographic Information System (GIS) in order to get a good overview of the energy flow, supply and use. Based on the gathered information, project ideas are suggested, and calculations are done to determine if biogas production, from household waste and sludge, could be a better option than today’s waste management where the waste is being transported to a nearby municipality for incineration, a service that Ljusdal’s municipality also have to pay for. The results from the calculations show that the total amount of energy that could be extracted from the annual produced biogas would reach about 1.9 GWh. The biogas could e.g.be used as a fuel in the district heating plants in the municipality. By using locally produced products a decreased import of energy carriers, e.g. light fuel oil, would be expected.

    The conclusions that could be drawn from this study are that a lot of biomass is produced in Ljusdal’s municipality, which is mainly exported in the form as raw material. Large amounts of hydroelectricity is produced in Ljusdal’s municipality, about 60% of the electricity is being exported. Wind mappings show that there are some areas of national interest for electricity production through wind power in the municipality. A deregulated European electricity market will probably lead to an increased electricity price, this in combination with the green certificate would lead to a more profitable electricity

    production through wind power and areas that are not of national interest at present could probably be of national interest in the future. There are also a large potential to increase the amount of biomass from the forestry remainings. Another potential energy source is the arable land where it probably would be possible to grow e.g. hemp for an energy conversion purpose. In Ljusdal’s municipality, there are possibilities in the field of energy which no one takes advantage of at present.

  • 63.
    Fredriksson, Jan
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Sandberg, Mats
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    The effect of false ceiling on the cooling capacity of passive chilled beams2009In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 44, no 7, p. 1426-1430Article in journal (Refereed)
    Abstract [en]

    Passive chilled beams are often used to provide cooling or additional cooling when the ventilation system cannot cope with the whole cooling load. The advantage of passive cooling is that it is a silent cooling. Often the chilled beams are installed above a false ceiling and thereby the room is subdivided into two compartments. From the chilled beam a plume is generated. Make-up air (return air) needs to flow into the upper compartment to substitute the airflow generated by the chilled beam. Therefore openings for this purpose are installed in the false ceiling. Small openings constitute a resistance to the flow and the locations of the openings affect the flow pattern. The overall performance was studied in a mock-up of a real office by changing both the size and position of the openings for the make-up air. A uniform heating source was arranged by covering the floor with a heating foil. The best location and size of the openings were explored by both recording the heat absorbed by the beam and the temperature in the room. Minimum temperature attained in the room is the signature of the most efficient cooling. To achieve efficient cooling with a uniform floor-based heating source, two conditions must be fulfilled: a) the return opening area must be at least equal to the horizontal area of the chilled beam; b) the return air openings must be located at the perimeter of the room. In general we can expect conditions a) and b) to be applicable irrespective of type of heat, but for point sources we could achieve the best cooling by placing the return air opening above the heat source.

  • 64.
    Frisk, Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Simulering av solavskärmning och nattkyla för att minimera kylbehovet för en kontorsbyggnad i Forsmark2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Society today depend on energy for it to work. The energy needed for heating buildings in the cold or cool buildings when it is warm. Energy is used for power lighting, appliances and transportation needs. Residential and commercial buildings account for 40% of total final energy consumption and half the energy residential buildings use goes to heating. To reduce energy consumption and stop global warming, it is important that new buildings are energy efficient. The targets that control the reduced energy consumption is EU 20/20 /20- goals. These goals should be reached by 2020 and will reduce greenhouse gas emissions by 20%, reduce energy consumption by 20%, increase the share of renewable energy to 20% and raise the share of biofuels in transport to 10%. For Sweden to achieve its environmental objectives Boverket have developed energy requirements for real estate buildings with the goal of reducing energy consumption in the residential sector. The requirements apply to new buildings and limiting the energy use for buildings heating, hot water and cooling. The thesis is about to perform a simulation of the night cooling and window shading of an office building. Simulations will be performed for the building's energy-, thermal power- and cooling demand. The program that has been used for the simulation is IDA ICE v4.7. The simulations showed that the solar shading reduced the effect of the cooling power by 4,8kW, a 13% reduction compared to a building without shading. Both the sun shading and night cooling was found to be effective to reduce cooling demand for building. Total cooling load can be reduced by 84% for the building at the given conditions. Energy simulation showed that the building meets the specific energy requirements of both the installed heating power and energy.

  • 65.
    Galarraga, Maider
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Heat balance of a historical church- transmission losses2014Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    The structure of old monumental churches differs a lot from contemporary buildings. The structural materials were wood, brick and stone. In order to construct high buildings with huge spans, thick massive walls and many massive columns were needed. Originally these buildings had no heating and for centuries the outdoor temperature determined the indoor climate. As churches are considered historical heritage buildings their renovation should be thoroughly studied.

     

                In this thesis the transmission losses of Hamrånge church will be analysed. Hence, the transmission trough walls and windows as well as the heat buffering of materials will be examined. In addition, the effect of possible reformation measurements will be concluded.

     

                Finally, this project belongs to a complete study of the church, were not only transmission losses are considered but also air infiltration losses and solar heat gain. That way, a comparison between them will be carried out in order to contribute to attain the objective of the project: possible restoration for church heating system with respect to preservation, energy requirements, thermal comfort and aesthetics.

  • 66.
    Gamage, Amila
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    CO2 Emission of Hotel Sector in Sri Lanka: A Case study & Scenario Analysis2014Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This research focused the CO2 emission and energy consumption pattern of Sri Lanka’s Hotel sector in both present and 2020 scenarios. It was proven from the literature survey that there was no study carried out to assess the current and future CO2 emission in Sri Lankan Hotel sector which is the government main focused area to develop within next 10 years of time. Also there is a long conversation in tourism sector from last few years and understood the importance of Sustainability of tourism business and identified the Green concept, Low carbon emission and less environmental impact are the key attributes to concern for the business sustainability.

    It was identified the CO2 emission in 2020 is 404,234 tonnes against the 121,458 tonnes of 2010 which is a huge impact to the environment because of expected growth of tourism sector. Also it was identified the CO2 emission per room in 2020 is 61.26 kg against the same 61.85 kg in 2010. This was slight change compared to the emission per room in 2010 but it will not considerably reduce the impact to the expected environmental pollution. The main energy consumption is from 5-star hotel category, which was contributed to 47% of total energy consumption even though this sector has contributed only 24% of total room capacity of the country in the present scenario of 2010, which was forecasted and identified the contribution to the total CO2 emission is 49.2% in 2020. This analyzing and modeling was done by using LEAP (Long Range Energy Alternative Planning System).

  • 67.
    Ghahremanian, Shahriar
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Numerical and experimental verification of initial, transitional and turbulent regions of free turbulent round jet2011In: 20th AIAA Computational Fluid Dynamics Conference 2011, 2011Conference paper (Refereed)
    Abstract [en]

    Three-dimensional simulation of the whole domain (initial, transition and fully developed regions) of round jet is essential in order to predict and to study the flow behavior of multiple jets (e.g. confluent jets). According to authors knowledge, numerical prediction of round jet with RANS models that has been presented by other researchers, are only in two-dimensional (axisymmetric) and mostly for the fully developed region. The inlet boundary conditions,  inlet velocity profile, turbulent kinetic energy and its dissipation rate at the diffuser exit has been governed from an earlier verified numerical simulation. In the present paper, results of three-dimensional modeling of isothermal, free, turbulent round jet with two two-equation (Low Re  and SST ), a transition three-equation ( ) and a transition four-equation (SST) eddy-viscosity turbulence models with resolved inlet profiles are compared and validated with hot-wire anemometry. This study shows that numerical simulation of round jet with SST  gives good agreement with measured mean longitudinal velocities, while transition models could only predict the initial region of round jet.

  • 68.
    Ghasemi, Milad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Hammodi, Hassan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Moosavi Sigaroodi, Homan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Parallel-Powered Hybrid Cycle with Superheating “Partially” by Gas Turbine Exhaust2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    It is of great importance to acquire methods that has a sustainable solution for treatment and disposal of municipal solid waste (MSW). The volumes are constantly increasing and improper waste management, like open dumping and landfilling, causes environmental impacts such as groundwater contamination and greenhouse gas emissions. The rationalization of developing a sustainable solution implies in an improved way of utilizing waste resources as an energy source with highest possible efficiency. MSW incineration is by far the best available way to dispose the waste. One drawback of conventional MSW incineration plants is that when the energy recovery occurs in the steam power cycle configuration, the reachable efficiency is limited due to steam parameters. The corrosive problem limits the temperature of the superheated steam from the boiler which lowers the efficiency of the system. A suitable and relatively cheap option for improving the efficiency of the steam power cycle is the implementation of a hybrid dual-fuel cycle.

    This paper aims to assess the integration of an MSW incineration with a high quality fuel conversion device, in this case natural gas (NG) combustion cycle, in a hybrid cycle. The aforementioned hybrid dual-fuel configuration combines a gas turbine topping cycle (TC) and a steam turbine bottoming cycle (BC). The TC utilizes the high quality fuel NG, while the BC uses the lower quality fuel, MSW, and reaches a total power output of 50 MW.  Using a high-quality fuel in cogeneration can prove to be beneficial for improving and enhancing the overall plant profitability and efficiency while eliminating the corrosion problems with conventional MSW firing. The need for few interconnections between the different subunits in a parallel-fueled system allows for a wider range of operation modes and leaves room for service modes of the subunit. The hybrid dual-fuel cycle will be assessed for optimal cycle configuration and evaluated to how it compares to the sum of two separate single-fuel plants with optimal cycle configurations. Investigation of such aspects is a very important issue in order to be able to fully promote an implementation of hybrid combined cycle. The work presented herein also concentrates on investigating scenarios that include a full-load and part-load analysis in both condensing and combined heat and power (CHP) mode of operation.

    Through simulations and evaluation of obtained data, the results strengthens the fact that the electrical efficiency of hybrid configurations increases at least with 2% in condensing mode and 1,5% in CHP mode, comparing it to the sum of two separate single-fuel units of similar scale. The simulations show increased electrical efficiencies when running the BC in part-load and the TC in full load, with a higher NG to MSW ratio. The results also indicated that it is possible to extract more power output from the cycle by operating in CHP mode, due to more energy being utilized from the input fuel. 

  • 69.
    Gomez, Adrian
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Bomhus Energi.
    Identification and evaluation of internal leakages of a BFB Boiler integrated within a pulp and paper mill.2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Alternative fuels like biomass have become really popular in the last decades as a substitute to fossil fuels. One of the most used technologies in Sweden for the obtention of the energy from the biomass is its direct combustion in a boiler. Bomhus Energi is a company with the purpose of creating steam and district heating for Billerudkorsnäs pulp and paper mill in Gävle and district heating for the city by operating a biomass BFB boiler. Despite being a quite new boiler, there are many sources of errors, losses and unnecessary costs. Between huge number of different losses that can happen in this kind of industrial boilers, the concern about internal leakages is not usually popular among plant designers and operators. This often leads to forget about them or not giving the importance that they could have.This study consists on, firstly, an analysis of different boiler equipment that have potential possibilities of internal leakages by mass and energy balances and by the tracking of possible mass losses. The second point of this thesis is to evaluate the cost of internal leakages that could have happen before, in order to be aware of how important they are. Additionally, measures are proposed in order to avoid or reduce the duration of the internal leakages, where the most common problem is the ignorance of their existence. This study focuses partially on the valve condition and maintenance. It is highly important to carry out valve maintenance procedures at least once per year during the general stop of the plant. Checking and verifying valve perfect conditions, can avoid a waste of a huge quantity of money just by replacing some internal elements that are possibly damaged due to the extreme working conditions. This small damages in valve can lead to a non-proper water tightening, which will be increasing its leakage over time. In the present paper, possible internal leakages through the valves belonging to the feedwater, steam drum, preheater and pressure vessel in general have been the principal aim. The key of this study was to take into account that biggest part of the draining system and valves that are supposed to be closed end in the Bottom blowdown tank. By then a deep study was done regarding this tank. The results show that there is a clear relationship between mass that is getting loss from feedwater tank and pressure vessel and the necessary cooling flow in the bottom blowdown tank. This means that if the cooling flow increases at the same rate as a possible leakage in mass and energy balance, there is an internal leakage somewhere in the system. The author proposes add an alarm to the DCS system in order to alert the plant operations of possible internal leakages. On the other hand, this paper also recommends to carry out a general valve maintenance per year and check which of them could be leaking, a general stop is the perfect time for carrying it out.In conclusion, the study finds that internal leakages can be even automatically detected if the system is provided with the necessary tools for it. The study concludes that internal leakages are not impossible to detect and their cost is non-negligible: the latest two internal leakages in the boiler, happened in the last two years, were from the feedwater draining system and from the steam drum heating loop with a total cost of 200,000 SEK (4240 SEK/day during 47 days) and 263,000 SEK (2120 SEK/day during 124 days) respectively. Additionally, days after the study, the plant general stop was carried out, finding that 12 valves were leaking due to internal damage. The cost of repairing the broken or damaged elements were almost negligible compared with the expected savings estimated in 2 Million SEK per year.

  • 70.
    Gustafsson, Dennis
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Comparing air quality in a training facility: What effects do air balancing have for carbon dioxide reduction?2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The link between a good indoor climate and environmental impacts e.g. global warming and different pollution in the air is something that are important today and will certainly become more important in the future with increased energy prices and new laws.

    Too keep the indoor air quality within limits is it important to have a good and competitive ventilationsystem.

    The ventilations function is mainly to supply fresh air and to remove polluted air from the room. It’s important that the ventilation system works as it should so that the indoor air quality is as good as possible. The lack of good ventilation can create several symptoms such as headaches, nausea, fatigue, poor concentration etc.

    In Sweden are ventilation control mandatory for every newly produced building and this control are repetitive usually every 3-6 years for some types of buildings.

     

    The foundation of this thesis is from a previous degree project performed by a master’s student in 2013 named Ander Barroeta with supervision of Magnus Mattsson and Taghi Karimipanah.

    The thesis was to improve and design a ventilation system in two rooms at a training facility named Friskis & Svettis in Gävle so that the CO2 level did not exceed 1000 ppm.

     

    In this thesis was the main goal to do similar measurements as the previous thesis and compare the results to see what difference air balancing has done to the ventilation system. Field measurements were performed at the training facility were the focus was on carbon dioxide but also on other parameters such as temperature, humidity and air velocity so that air exchange rate could be calculated. With these parameters can evaluations be made to see if air balancing of the ventilation system made any difference in indoor air quality.    

     

    During measurements in one of the training rooms where spinning is exercised was carbon dioxide levels up to 3300 ppm measured which is above the recommended indoor limit at 1000 ppm. If that room should be design to not exceed 1000 ppm must the air exchange rate increase from 6.3 h-1 to 35.1 h-1.

  • 71.
    Gustafsson, Mattias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Pyrolys för värmeproduktion: Biokol den primära biprodukten2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Pyrolys innebär att exempelvis biobränsle hettas upp i syrefattig miljö för att bilda pyrolysgas och kol. Pyrolysgasen kan brännas för att producera värme med låga utsläpp och kolet har en mängd användningsområden; jordförbättringsmedel, fodertillskott, filtermaterial, kolfastläggning, energibärare, ståltillverkning m.m. Om krav på bränsle och användningsområde för kolet uppfylls kan kolet certifieras som biokol. Syftet med den här rapporten är att utreda om pyrolystekniken är ett hållbart, tekniskt och ekonomiskt alternativ till pellets- och flisförbränning för värmeproduktion. Målet är att förmedla pyrolysens tekniska och ekonomiska förutsättningar, såväl positiva som negativa. Rapporten är baserad på en kombination av litteraturstudier, djupintervjuer, besök vid anläggningar och referensgruppsamtal.

     

    Pyrolys har använts i tusentals år för att producera kol. I Amazonas upptäcktes landområden med en sammalagd yta större än Storbritannien i vilka jorden var kolsvart. Denna svarta jord, terra preta, är berikad med kol och har därmed blivit mycket bördigare än omgivande, ursprunglig jord. I Sverige framställdes kol för att tillgodose metallindustrin med bland annat produktionsmaterial och bränsle. Till skillnad från pellets- och flisförbränning kan pyrolystekniken använda en stor mängd olika bränslen så länge de uppfyller krav på energidensitet och fukthalt. Marknaden för biokol växer i bl.a. Tyskland men är ännu liten i Sverige. De leverantörer av pyrolysanläggningar som besökts i denna rapport, Pyreg och Carbon Terra, gör anläggningar med syfte att producera biokol. Pyreg har utvecklat en process med skruvreaktor och integrerad pyrolysgasbrännare för att t.o.m. kunna använda avloppsslam som bränsle. Carbon Terras process är enkel och robust med fokus att producera mycket kol.

     

    Pyrolysteknikens styrkor är flexibiliteten att välja olika typer av bränslen, låga utsläpp, liten negativ miljöpåverkan och kolets olika användningsområden. Ser man till svagheterna är de marknadsrelaterade; outvecklad svensk marknad och okunskap om kolets användningsområden. Dessutom gör pyrolysanläggningarnas statiska effektuttag att de är mindre flexibla än pellets- och flispannor. I en tid då klimatförändringarna letar akuta lösningar medför kolfastläggning och biokol som jordförbättringsmedel stora möjligheter tillsammans med omvandling av pyrolysgas till fordonsbränsle. Dock är den befintliga pellets- och flisförbränningen väletablerad som uppvärmningsteknik, vilket kan utgöra ett hot mot pyrolysteknikens intåg på marknaden. Avsaknaden av regelverk pga. kompetensbrist kan också försvåra för etablering av pyrolysanläggningar.

     

    Slutsatsen i denna rapport är att pyrolystekniken är ett bra alternativ till konventionell pellets- och flisförbränning om man kan hantera att värmeproduktinen är statisk och att man beaktar kolets värde. Värmeproduktion från pyrolysgas ger lägre utsläpp av bland annat CO, NOx och stoftpartiklar än pellets- och flisförbränning och om kolet används för kolfastläggning är möjligheten till globala klimateffekter betydande. Det som starkast påverkar den ekonomiska kalkylen är kostnaden för bränslet och intäkten på kolet. För att gardera sig mot den outvecklade biokolmarkanden i Sverige har kalkylerna i denna rapport baserats på försäljning av biokol som jordförbättringsmedel, vilket ger låga intäkter jämfört med andra användningsområden. Styrkan i att valet av bränsle är flexibelt gör det möjligt att ha en bränslekostnad på noll om materialet annars ses som avfall. Marknaden för kol i Sverige är outvecklad vilket kräver ett aktivt arbete från de som ger sig in branschen, men om utvecklingen följer den i Tyskland ser de ekonomiska förutsättningarna starka ut.

  • 72.
    Gustafsson, Mattias
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Thygesen, Richard
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Karlsson, Björn
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Ödlund, Louise
    Division of Energy Systems, Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Rev-Changes in Primary Energy Use and CO2 Emissions: An Impact Assessment for a Building with Focus on the Swedish Proposal for Nearly Zero Energy Buildings2017In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, no 7, article id 978Article in journal (Refereed)
    Abstract [en]

    In the European Union's Energy Performance of Buildings Directive, the energy efficiency goal for buildings is set in terms of primary energy use. In the proposal from the National Board of Housing, Building, and Planning, for nearly zero energy buildings in Sweden, the use of primary energy is expressed as a primary energy number calculated with given primary energy factors. In this article, a multi-dwelling building is simulated and the difference in the primary energy number is investigated when the building uses heat from district heating systems or from heat pumps, alone or combined with solar thermal or solar photovoltaic systems. It is also investigated how the global CO2 emissions are influenced by the different energy system combinations and with different fuels used. It is concluded that the calculated primary energy number is lower for heat pump systems, but the global CO2 emissions are lowest when district heating uses mostly biofuels and is combined with solar PV systems. The difference is up to 140 tonnes/year. If the aim with the Swedish building code is to decrease the global CO2 emissions then the ratio between the primary energy factors for electricity and heat should be larger than three and considerably higher than today.

  • 73.
    Haghshenas, Samira
    et al.
    School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Sajadi, Behrang
    School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Cehlin, Mathias
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Multi-Objective Optimization of Impinging Jet Ventilation Systems: Taguchi Based CFD Method2018In: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 11, no 6, p. 1207-1214Article in journal (Refereed)
    Abstract [en]

    This paper presents a Taguchi method-based approach that can optimize the operating performance of impinging jet ventilation (IJV) systems with limited computational fluid dynamics (CFD) simulation results. The Taguchi optimization calculation finds the best operating design for the weighted overall objective function as a presenter of the multi-objective function problem. The method is used to optimize the operating characteristics of an IJV system considering the factors of supply air temperature, level of the return air vent and percentage of the air exhausted through the ceiling to achieve an overall best performance of thermal comfort, indoor air quality (IAQ) and system energy performance as the objective functions. The study indicates the contribution percentage for each factor in each objective function. The level of the return air vent, the supply air temperature, and the percentage of air exhausted through the ceiling have a contribution of 35.8%, 28.5%, and 35.8% in the objective functions, respectively. Based on the results, the best performance of the IJV system happens when the inlet air temperature is 18 °C, the height of the return air vent is 2 m above the floor, and the percentage of air exhausted through the ceiling is 22.5%.

  • 74.
    Hallkvist, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Förundersökning av möjligheten till modifiering av kylvattenintag: Undersökning av möjligheten till modifierat kylvattenintag vid Forsmarks kärnkraftsanläggning2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Elproduktion är en viktig del i dagens samhälle och hur man producerar elen har blivit en viktig fråga som diskuteras flitigt i Sverige och i omvärlden. I Sverige har elanvändningen och elproduktionen varit i närmaste oförändrad sedan 90-talet. Elanvändningen i Sverige är ca 140 TWh per år och drygt 40 % av detta produceras av kärnkraften. Detta medför att kärnkraften är en viktig del av den Svenska elproduktionen. Kärnkrafts-bolagen som äger kärnkraftverken i Sverige letar alltid efter sätt för att förbättra säkerheten på sina anläggningar samt att genomföra verkningsgradsförbättringar som minskar bränsleanvändningen. Det här arbetet inriktar sig på att öka produktionsförmågan genom att genomföra en verkningsgradsförbättring. Rapporten använder sig av en kvantitativmetod och behandlar vilka förutsättningar samt lösningar det finns till att sänka kylvattentemperaturen vid kärnkraftsanläggningen i Forsmark. Arbetet begränsar sig till att endast ge en överblick för vilka lösningar som finns. Ingen av lösningarna undersökas på djupet med undantag på mammutpumpar. Forsmark kärnkraftsanläggning består utav tre stycken reaktorer och använder tillsammans ca 145 m3/s kylvatten för att kyla ner ångan i turbinkondensatorerna. Att sänka temperaturen på kylvattnet med en grad innebär en verkningsgradsförbättring på 0,444 % vilket är utrett i rapporten. En sådan förbättring innebär att Forsmarks reaktor 3 ökar sin nettoeffekt med 5,25 MW. Att sänka kylvattentemperaturen kan göras på många sätt och i denna rapport ansågs det vara relevant att undersöka lösningar som lyfter upp bottenvatten eller blandar om vattnet ifrån olika nivåer i havet. De lösningarna som undersöktes var mammutpumpar, luftridå en vägg längst ytan, utgrävning av kylvattenkanal, förlängning av existerande kanal, djupvattenintag och strömbildare på botten. Den lösning som ansågs vara den mest attraktiva lösningen var luftridå och det var på grund utav att dess fördelar var många och dess nackdelar inte var alltför stora. De slutsatser som görs i denna rapport kan användas i andra reaktorer runtom i världen som har liknande förutsättningar.

  • 75.
    Hang, Jian
    et al.
    University of Hong Kong.
    Li, Yuguo
    University of Hong Kong.
    Sandberg, Mats
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building science - installation technology.
    Claesson, Leif
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, BMG Laboratory.
    Wind Conditions and Ventilation in high rise long Street Models2010In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 45, no 6, p. 1353-1365Article in journal (Refereed)
    Abstract [en]

    We regarded high-rise cities as obstacles and channels to wind. We first studied wind conditions and ventilations in idealized high-rise long street models experimentally and numerically with a constant street width (W = 30 mm), variable street heights (H = 2 W, 2.5W, 3W, 4W), variable street lengths (L = 47.4W, 79W. 333W, 667W) and a parallel approaching wind. The flow rates penetrating into windward entries are a little larger than the reference flow rate in the far upstream free flow through the same area with windward entries in all models. The stream-wise velocity decreases along the street as some air leaves upwardly across street roofs. Near the leeward entry, there is a downward flow which brings some air into the street and results in an accelerating process. In the neighborhood scale long streets (L = 47.4W and 79W), wind in taller streets is stronger and the ventilation is better than a lower one. For the city scale long streets (L = 333W and 667W), a constant flow region exists where the vertical velocity is zero and the stream-wise velocity remains constant. In such regions, turbulent fluctuations across the street roof are more important to air exchange than vertical mean flows. In a taller street, the process to establish the constant flow conditions is longer and the normalized balanced horizontal flow rate is smaller than those in a lower street. In the city scale long streets, the turbulence exchange rate can be 5-10 times greater than the mean flow rate. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

  • 76.
    Hasan, Farhan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. University of Gävle.
    Possibilities of Geothermal Energy and its Competitiveness  with Other Energy Sources2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Geothermal Energy is one of the common talks at present. It has the potential to run long term and can provide base-load energy, at the same time it helps to reduce the greenhouse gas emissions. It is found almost everywhere on earth. The resources of geothermal energy range from shallow ground to hot water or hot rock, which can be found few kilometers below the surface and even deeper to magma where the temperature is extremely high. Since its discovery from the ancient times, many technologies have been developed to understand or use geothermal energy properly. 

    This report is based on literature survey of geothermal energy compared to other energy sources in terms of construction, supply energy and the advantage-disadvantage of the system. From this study it has been found that geothermal power plant does not need external fuel to operate, that’s why the price of geothermal energy does not go up like oil and gas, in USA the cost of geothermal electricity ranges from $0.06 to $0.10 per kilowatt-hour and besides it is one of the most clean, reliable and renewable energy source, which is environment friendly and cheaper than other energy sources.

  • 77.
    Hillman, Karl
    Institutionen för energi och miljö, Miljösystemanalys, Chalmers Tekniska Högskola, Göteborg.
    Environmental Assessment and Strategic Technology Choice: The Case of Renewable Transport Fuels2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The scale of the required changes is huge, and time is limited if we are to avoid the most severe effects of climate change. To reduce greenhouse gas emissions from road transport, several fuels and electricity originating from renewable energy sources have been proposed, all of them in different stages of development and with various and shifting environmental impacts. This thesis aims at increasing the usefulness of environmental assessments of emerging technologies as a basis for strategic technology choice. Recommendations for the design and interpretation of such assessments are presented, with a special focus on life cycle assessment (LCA) methodology. A long time perspective, the possibility of system change, and the inclusion of socio–technical change processes allows for the revision of methodological assumptions normally made in LCA of current products. To guide the selection of technologies, there is need for assessment both of technology and of interventions. For the assessment of technology, an attributional approach is applied. Paper I discusses and tests the feasible futures and future performance to be considered in attributional LCAs. The results indicate that the environmental impact attributable to a number of selected fuels, as well as the ranking of them, largely depend on assumptions regarding background systems and by-product use. For the assessment of interventions, a consequential approach is applied. Extensive studies of socio–technical change processes contribute insight into relevant cause–effect chains that can be included in environmental assessments of emerging technologies. A comparison between the Swedish and the Dutch innovation systems for renewable fuels reveals the unfolding of dynamics influenced by shared background factors (Paper II). An investigation of the Swedish history of alternative fuels is used in developing a framework for analysing interaction between emerging technological systems (Paper III). Insights into socio–technical change processes are then used to elaborate scenarios for the future development of renewable fuels in Sweden resulting from current policy choices (Paper IV). In a final paper (Paper V), historical and future cause–effect chains are taken into account in a consequential LCA of ethanol of varying origins in Sweden for the 1990–2020 period. It is concluded that for emerging technologies in an early stage of development, the contribution of an intervention to system change may be more important than the direct change in environmental impact. Finally, it is suggested that all aspects of socio–technical change and the resulting environmental impact may not have to be included in quantitative environmental assessments, such as LCA. ‘Environmental assessment’ could very well include a group of parallel studies that illuminate different cause–effect chains resulting in changed environmental impact, and that are part of a society-wide learning process.

  • 78.
    Hillman, Karl
    Institutionen för energi och miljö, Miljösystemanalys ; Göteborgs miljövetenskapliga centrum (GMV).
    LCA and Strategic Choice of Biofuels2007In: LCA of Energy, Energy in LCA - SETAC Europe 14th LCA Case Studies Symposium, 3-4 December 2007, Göteborg, Sweden - Extended abstracts, 2007, p. 91-94Conference paper (Other academic)
  • 79.
    Hillman, Karl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental engineering.
    Materialåtervinning och klimatnytta: Hur räknar återvinningsaktörer i Sverige?2013Report (Other academic)
    Abstract [sv]

    Syftet med den här studien är att sammanställa hur aktörer verksamma i återvinningsbranschen i Sverige tar fram siffror på, och kommunicerar klimatnyttan vid återvinning av olika material, samt att undersöka hur väl de använda metoderna överensstämmer med vetenskapliga studier. Resultaten visar att flera stora aktörer inom branschen kommunicerar klimatnytta på likvärdiga sätt, i syftet att visa på ”den klimatnytta som återvinningen redan idag medför och vilken potential som finns att öka återvinningens bidrag till en minskad klimatpåverkan”. Detta innebär bland annat att aktörerna har för avsikt att vara både tillbakablickande och framåtblickande, samt att företag inte försöker jämföra sig med varandra med utgångspunkt i klimatnytta.

    Det tillgängliga underlaget och hur det används för beräkningar och kommunikation av klimatnytta visar sig ha flera brister som är signifikativa för miljöbedömningar. I huvudsak handlar dessa om att man kombinerar siffror från studier med olika antaganden vad gäller tidsperspektiv, geografisk täckning och val av växthusgaser, vilket innebär att resultaten inte blir rättvisande för något ändamål, och att man i princip inte kan dra några slutsatser från materialet. Samtidigt finns det gott om studier som rätt hanterade kan komma till användning för de syften de är framtagna för.

    I rapporten framhålls tre viktiga aspekter att förbättra vid beräkning och kommunikation av klimatnyttan med återvinning, samt vid användning av resultaten. För det första handlar klimatnytta inte bara om koldioxid, och miljönytta handlar inte bara om växthusgaser. Beräkningar av andra typer av utsläpp kan visa på ytterligare fördelar och eventuella nackdelar med återvinning. För det andra bör metodval och antaganden vara kopplade till studiens syfte, samt vara konsekventa, för att ge rättvisande och jämförbara resultat. För det tredje bör resultaten från olika studier endast användas för det syfte de är avsedda för, alternativt bearbetas för att kunna användas i andra sammanhang.

    Eftersom samtliga aktörer inom återvinningsbranschen i Sverige verkar ha liknande syften med sin kommunikation av klimatnyttan med materialåtervinning, och då tillgängligt dataunderlag inte ger något utrymme för att jämföra företag med varandra identifieras följande möjligheter för det fortsatta arbetet.

    1. Först och främst kan man inom branschen stämma av och eventuellt enas om vilka olika syften man vill uppnå med att beräkna klimatnytta.
    2. Därefter kan man gå vidare och arbeta tillsammans för att komma tillrätta med de brister som finns i underlaget, samt i hur det används. En möjlighet är att anlita en expert för att välja ut, bearbeta och komplettera det underlag som finns, så att det kan användas för de syften man vill uppnå. Branschen kan sedan försöka komma överens om gemensamma siffror, samt om hur de bör kommuniceras på lämpligt sätt.
    3. En framtida möjlighet inom området kan också vara att utveckla gemensamma riktlinjer för hur man ska ta fram och kommunicera företagsspecifika siffror på klimatnytta, i syfte att möjliggöra jämförelser mellan olika företag.
  • 80.
    Hillman, Karl
    et al.
    , Institute for Management of Innovation and Technology (IMIT) and University of Gothenburg, Sweden.
    Nilsson, Måns
    Stockholm Environment Institute (SEI), Sweden.
    Rickne, Annika
    University of Gothenburg and Institute for Management of Innovation and Technology (IMIT), Sweden.
    Magnusson, Thomas
    Institute for Management of Innovation and Technology (IMIT) and Linköping University, Sweden.
    Framework for analysing the governance of innovation systems for sustainable technology2009Conference paper (Other academic)
    Abstract [en]

    Fostering sustainable technologies –a framework for analysing the governance of innovation systemsKarl Hillman, Post-doc researcher, Institute for Management of Innovation and Technology (IMIT) and University of Gothenburg,SwedenMåns Nilsson, Associate professor, Stockholm Environment Institute (SEI), SwedenAnnika Rickne*, Associate professor, University of Gothenburg and Institute for Management of Innovation and Technology (IMIT), SwedenThomas Magnusson, Assistantprofessor, Institute for Management of Innovation and Technology (IMIT) and Linköping University, SwedenAbstractThere is an ever-growing recognition among policy-makers, industries and analysts that the development and diffusion of technological innovations need governing in order to contribute to societal goals related to sustainability, such as climate change mitigation and resource efficiency. Yet, little is known about how different types of governance influence innovation processes, and what may be effective governance arrangements to pursue to influence the development and diffusion of sustainable technological innovations. This paper develops a framework for the analysis of governance arrangements aimed at fostering more sustainable technological innovations. The framework addresses important debates in governance and innovation research. First, it addresses a critical gap in the literature on technological innovation systems (TISs) which is the connection between governance arrangements and the functionality of the TIS. Second, it contextualizes this connection in relation to the multi-level perspective (MLP) to transitions, assuming that governance arrangements influence in different ways the functionality of the TIS depending on the structure, stability and positioning of the TIS in relation to the regime. Third, it develops a comprehensive heuristic to examine the prevalence, role and effectiveness of various modes of governance, departing from a simple typology of "who governs", "how do they govern", and "what isgoverned".The framework prompts a temporal causal analysis of predominantly qualitative nature.

  • 81.
    Hillman, Karl
    et al.
    Institute for Management of Innovation and Technology (IMIT).
    Nilsson, Måns
    Rickne, Annika
    Magnusson, Thomas
    Governance in technological innovation systems: biofuels and hybrid vehicles in Sweden2011Conference paper (Other academic)
  • 82.
    Hillman, Karl
    et al.
    Environmental Systems Analysis, Department of Energy and Environment, Chalmers University of Technology, Göteborg, Sweden.
    Sandén, Björn A.
    Environmental Systems Analysis, Department of Energy and Environment, Chalmers University of Technology, Göteborg, Sweden.
    Exploring technology paths: The development of alternative transport fuels in Sweden 2007–20202008In: Technological forecasting & social change, ISSN 0040-1625, E-ISSN 1873-5509, Vol. 75, no 8, p. 1279-1302Article in journal (Refereed)
    Abstract [en]

    By using socio-technical scenarios, we investigate how present policy choices may affect the development of alternative transport fuels in Sweden. One important choice for policy lies in the balance between general tax exemptions stimulating the market for alternative fuels, and funding of research and development more directly promoting new technology. The implications of this choice are illustrated with four diverging development paths until 2020. In the market-oriented scenarios, we illustrate consequences of breaking the dominance of entrenched technologies and demonstrating a growing market potential for alternatives, but also the risks with a large focus on first generation renewable fuels. In the technology-oriented scenarios, we point out the value of keeping variety among niches in this stage of the transition. In conclusion, if policy is implemented without taking the dynamic forces within the system into account, there is a risk that any measure leads the system into a dead end. But if policy strives to balance the development in different parts of the technological system while making use of various prevailing forces of change, a multitude of different efforts can contribute to the development of a more sustainable transport system.

  • 83.
    Hillman, Karl
    et al.
    Institutionen för energi och miljö, Miljösystemanalys.
    Sandén, Björn A.
    Institutionen för energi och miljö, Miljösystemanalys.
    Time and scale in Life Cycle Assessment: the case of fuel choice in the transport sector2008In: International Journal of Alternative Propulsion, ISSN 1471-0234, E-ISSN 1741-8011, Vol. 2, no 1, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Life Cycle Assessments (LCA, including Well-to-Wheel studies) that are to support decisions that strive to change large technical systems need to consider time and scale related factors, which are given little attention in standard LCA procedures. Here, we address three issues and provide examples from the case of alternative fuels. First, shifting time frame gives room for technical development that should affect not only the choice of performance data, but perhaps also the functional unit and the selection of technologies under study. Secondly, background systems, such as heat and power production, change over time and increased production volumes of the alternative fuel change the transport system that is used to produce transport fuel. We show that such changes have consequences not only for Greenhouse Gas (GHG) emissions from each fuel-chain, but also for the ranking order of, e.g. Rapeseed Methyl Esther (RME) and ethanol in terms of GHG emissions. Finally, different types of feedstock are available in different quantities and different by-product markets vary in size. Key markets for RME by-products in EU correspond to an RME production that covers about 3% of transport fuel demand. Consequently, GHG emissions that are allocated to the fuel should change with the scale of adoption

  • 84.
    Hillman, Karl
    et al.
    Environmental Systems Analysis, Department of Energy and Environment, Chalmers University of Technology, Göteborg, Sweden.
    Suurs, Roald
    Innovation Studies, Department of Innovation and Environmental Sciences, Utrecht University, Utrecht, The Netherlands.
    Hekkert, Marko
    Innovation Studies, Department of Innovation and Environmental Sciences, Utrecht University, Utrecht, The Netherlands.
    Sandén, Björn A.
    Environmental Systems Analysis, Department of Energy and Environment, Chalmers University of Technology, Göteborg, Sweden.
    Cumulative causation in biofuels development: a critical comparison of the Netherlands and Sweden2008In: Technology Analysis & Strategic Management, ISSN 0953-7325, E-ISSN 1465-3990, Vol. 20, no 5, p. 593-612Article in journal (Refereed)
    Abstract [en]

    Supporting the development and diffusion of sustainable innovations has become a dominanttopic on the political agenda of many countries. However, this has proven to be a difficult task. Toincrease insight in such processes, this paper takes biofuel technologies in the mobility sector asthe topic of a comparative case study. Various national governments have supported innovationtrajectories around biofuels. We analyse, assess and compare two such trajectories as theyhave developed so far: one in the Netherlands and one in Sweden. A Technological InnovationSystem (TIS) approach is applied. A TIS is constituted by actors, networks and institutions,that are to be gradually constructed around a technology. We analyse whether governmentsand entrepreneurs have succeeded in developing seven key processes, or system functions,necessary for the development and diffusion of biofuel technologies. By analysing the build-upof system functions over time we identify virtuous and vicious forms of cumulative causation.The Dutch and Swedish TISs for biofuels are followed from 1990 to 2005. Our comparisonshows that, due to the fulfilment of system functions and the emergence of cumulative causation,the Swedish TIS has reached a market expansion and broad social implementation of biofuels,whereas the Dutch TIS has established considerably less.

  • 85.
    Holmgren, Kristina
    et al.
    Department of Mechanical Engineering, Division of Energy Systems, Linköping Institute of Technology, Linköping, Sweden.
    Amiri, Shahnaz
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik. Department of Mechanical Engineering, Division of Energy Systems, Linköping Institute of Technology, Linköping, Sweden.
    Internalising external costs of electricity and heat production in a municipal energy system2007In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 35, no 10, p. 5242-5253Article in journal (Refereed)
    Abstract [en]

    Both energy supply and waste treatment give rise to negative effects on the environment, so-called external effects. In this study, monetary values on external costs collected from the EU's ExternE project are used to evaluate inclusion of these costs in comparison with an energy utility perspective including present policy instruments. The studied object is a municipal district heating system with a waste incineration plant as the base supplier of heat. The evaluation concerns fuels used for heat production and total electricity production, for scenarios with external costs included and for a scenario using the present policy instrument. Impacts of assumptions on marginal power producers (coal or natural gas power plants) are investigated, since locally produced electricity is assumed to replace marginal power and thus is credited for the avoided burden. Varying levels of external costs for carbon dioxide emissions are analysed. The method used is an economic optimisation model, MODEST. The conclusion is that present policy instruments are strong incentives for cogeneration, even when external costs are included. Waste is fully utilised in all scenarios. In cases where coal is the marginal power producer, more electricity is produced; when natural gas is the marginal power producer, less is produced. There are several uncertainties in the data for external costs, both methodological and ethical. In the ExternE data, not all environmental impacts are included. For waste incineration, ashes are not included, and another difficulty is how to treat the avoided burden of other waste treatment methods. 

  • 86. Holmström, David
    et al.
    Bisaillon, Mattias
    Eriksson, Ola
    Hellström, Hanna
    Nilsson, Karolina
    Framtida marknaden för biogas för avfall: Delprojekt 3 inom projektet Perspektiv på framtida avfallsberedning2013Report (Other academic)
  • 87.
    Holmström, Susanne
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Fjärrvärmesystem2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a report written for an examination project C-level, on the subject of energy. The examination project is a product of the FVB Sweden AB (district heating bureau). It started with a meeting with Stefan Jonsson FVB Sweden AB, were he explained the content of the project, and from this a presentation of the problem was made. The problem that needed to be solved was how they could control the valves in the system to provide heating to everyone in the system. The valves are often oversized so the pump in the heating plant would have to be enormous to be able to provide enough flow to be sufficient, if everyone in the system had there valves fully opened.

     

    I came up with two solutions to the problem, one was a wireless network that could keep track of the valves and the other solution was an extra sensor that was placed on the radiator. The purpose for that was to open the valve if the temperature dropped more than one degree inside. With the help of a program called IDA it was calculated that, if the temperature drop five degrees, they would have sixteen hours at the heating power plant to open the flow before the sensor open the valves.

     

    After careful consideration I came up with the conclusion that the wireless network must be the best solution. Mostly because you can monitor all the clients in the system from the heating power plant and that will make it easier to discover faults and temperature differences.

    Wireless networks is already a well tested solution in form of wireless controlled electricity meters so it shouldn’t be to much of a problem connecting these sensors to it either.

  • 88.
    Jagodaarachchi, Wasana Chinthaka
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. KTH Royal Institute of Technology.
    Ekanayake, Anuruddha
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. KTH Royal Institute of Technology.
    Evaluation of Technical, Environmental and Financial Viability of Tri – Generation in Apparel Sector of Sri Lanka2012Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Apparel industry is the main source of foreign currency for Sri Lanka and is the one thatprovides most number of local employments. It has been severely affected by thecontinuous rise of fossil fuel prices. Industry is also under pressure by the governmentsand buyers (major retail chains and global apparel brands who has their supply chainemission reduction goals) to minimize the emissions as well as to reduce the energyconsumption. In view of that, this study was focused on the viability of using combinedheating, cooling and power generation or the Tri‐Generation (TG) at factory level whichhas never been tried in the apparel industry in Sri Lanka.After the literature survey, local apparel sector was analyzed and then the factorieswere categorized in to five main groups out of which the most affected group by theenergy cost, the fabric manufacturing, was selected as the focus group. One factory fromthe focus group, Textures Jersey (TJ) was selected for the initial case study. After a detailenergy audit at TJ, results were used to evaluate the environmental and economicalviability of two selected TG combinations. One with most favorable results wasoptimized and then studied in detail to see if it is environmentally, economically andtechnically viable to TJ. Result of the detail analysis of the optimal TG combination wasused to come up with general guidelines to implement viable TG plants for local apparelindustry.As per the results TJ can enjoy substantial benefits (15‐35% energy cost saving) byopting to use a TG, fired by either coal or biomass (saw dust briquettes or firewood).Biomass is preferred over coal due to low prices and reduced emissions. Not needing ofa complicated fuel preparation and feeding system as in a coal fired TG system is also anadvantage of Bio‐mass. However biomass has relatively more supply chain issuescompared to coal. A universal solution that can be used by any apparel factory cannot bearrived at, as economics of the TG is highly depended on local parameters. Howeverselecting the capacity of a TG based on the process heating demand of a factory isbeneficial if it has a 24 hour operation. Intermittent operation of TG is not economical asfrequent start‐up and shut‐down of a TG is not practical. Further, increasing electricitygeneration in TG is not very attractive owing to subsidized tariffs.

  • 89.
    Jahedi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Computational study of multiple impinging jets  on heat transfer2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This numerical study presents investigation of impinging jets cooling effect on a hot flat plate. Different configuration of single jet, 5-cross and 9-square setups have been studied computationally in order to understand about their behaviour and differences behind their physics. Moreover, a specific confined wall was designed to increase two crucial parameters of the cooling effect of impinging jets; average heat transfer coefficient of impingement wall and average air temperature difference of outlet the domain and jet inlet.

    The 2-D simulation has been performed to design the confined wall to optimise the domain geometry  to achieve project goals contains highest average heat transfer coefficient of hot plate in parallel to highest average air temperature difference of outlet. Different effective parameters were chosen after 2-D simulation study and literature review; Jet to wall distance H/D = 5, Radial distance from centre of plate R/D = 20, jet diameter D = 10 mm.

    The 3-D computational study was performed on single jet, 5-cross and 9-square configurations to investigate the differences of results and find best setup for the specific boundary condition in this project.

    Single jet geometry reveals high temperature level in the outlet, but very low average heat transfer coefficient due to performance of a single jet in a domain (Re= 17,232).

    In the other side, 5-cross setup has been studied for Reynolds number of 9,828, 11,466, 17,232 and 20,000 and it was found that range of 11,466 to 17,232 performs very well to achieve the purposes in this study. Moreover, turbulence models of ,  and  have been used to verify the models (Re=17,232) with available experimental data for fully developed profile of the jets inlets and wall jet velocity and Reynolds stress components near the wall boundary condition. All three turbulence models predict well   the velocity components for jets fully developed profile and for wall boundary condition of the target plate. But since  model has been validated with the Reynolds stress components by experimental data, therefore is more reliable to continue the study with verified simulation.

    Finally 9-square configuration was investigated (Re=17,232) and the result compared with other setups. It was concluded that 5-cross multiple jets is best design for this project while 9-square multiple impinging jets also fulfils the project purpose, but for extended application in industry each setup is suitable for specific conditions. 5-cross multiple jets is good choice for large cooling area which can be used in number of packages to cover the area, while 9-square jets setup performs well where very high local heat transfer is needed in a limited area.

  • 90.
    Jahedi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Berntsson, Fredrik
    Department of Mathematics, Linköping University, Linköping, Sweden.
    Wren, Joakim
    Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Department of Management and Engineering, Linköping University, Linköping, Sweden.
    Transient inverse heat conduction problem of quenching a hollow cylinder by one row of water jets2018In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 117, p. 748-756Article in journal (Refereed)
    Abstract [en]

    In this study, a two-dimensional linear transition inverse heat conduction problem (IHCP) was solved using the Generalized Minimal Residual Method (GMRES) in quenching process by water jets. The inverse solution method was validated by set of artificial data and solution sensitivity analysis was done on data noise level, regularization parameter, cell size, etc. An experimental study has been carried out on quenching a rotary hollow cylinder by one row of subcooled water jets. The inverse solution approach enabled prediction of surface temperature and heat flux distribution of test specimen in the quenching experiments by using measured internal specimen temperature. Three different boiling curves were defined in the quenching process of a rotary cylinder. Result obtained by the inverse solution showed clear footprint of rotation in surface temperature and heat flux on each revolution of cylinder and temperature variation damping from quenching surface toward interior of specimen.

  • 91.
    Jahedi, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Division of Energy Systems, Department of Management and Engineering, Linköping University.
    Experimental study of quenching process on a rotating hollow cylinder by one row of impinging jets2017In: 9th World Conference on Experimental Heat Transfer, Fluid Mechanics and Thermodynamics, 12-15 June, 2017, Iguazu Falls, Brazil, 2017Conference paper (Refereed)
    Abstract [en]

    Quenching cooling rate of rotary hollow cylinder by one row of water impinging jets has been experimentallystudied. Water jets (d = 8 mm) with sub-cooling 55 to 85°C and Reynolds number 8,006 to 36,738 impinged over rotaryhot hollow cylinder (rotation speed 10 to 70 rpm) with initial temperature 250 to 600°C. Impingement impact angle of row of jets varied between 0 to 135° and jet-to-jet spacing in row patten was 2 to 8d. The results revealed more uniformityon cooling rate of quenching in smaller jet-to-jet spacing (2 and 4d) where wetting front regions are located closer toneighbor jet’s region. By increasing spacing, footprint of annular transition region was highlighted in quenching coolingrate contour. A distinct quenching characteristic was obtained for impingement impact angle of 0° compare to otherangles. With initial temperature above the Leidenfrost temperature, low cooling rate was achieved in film and transitionboiling compare to a steep increase of cooling rate at start of quenching with higher maximum heat transfer for experimentswith initial temperatures less than Leidenfrost temperature. The effect of other parameters on quenching coolingrate was highlighted in film and transition boiling while no significant differences were observed in nucleate boiling.

  • 92.
    Janbakhsh, Setareh
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Linköpings universitet, Energisystem.
    A Ventilation Strategy Based on Confluent Jets: An Experimental and Numerical Study2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. In this study, the supply device can be described as an array of round jets on a flat surface attached to a side wall. Multiple round jets that issue from supply device apertures are combined at a certain distance downstream from the device and behave as a united jet or so-called confluent jets. Multiple round jets that are generated from the supply device move downward and are attached to the wall at the primary region, due to the Coanda effect, and then they become wall confluent jets until the floor wall is reached. A wall jet in a secondary region is formed along the floor after the stagnation region.

    The characteristics of the flow field and the ventilation performance of conventional wall confluent jets and modified wall confluent jets supply devices are investigated experimentally in an office test room. The study of the modified wall confluent jets is intended to improve the efficiency of the conventional one while maintaining acceptable thermal comfort in an office environment. The results show that the modified wall confluent jets supply device can provide acceptable thermal comfort for the occupant with lower airflow rate compared to the conventional wall confluent jets supply device.

    Numerical predictions using three turbulence models (renormalization group (RNG k– ε), realizable (Re k– ε), and shear stress transport (SST k– ω) are evaluated by measurement results. The computational box and nozzle plate models are used to model the inlet boundary conditions of the nozzle device. In the isothermal study, the wall confluent jets in the primary region and the wall jet in the secondary region, when predicted by the three turbulence models, are in good agreement with the measurements. The non-isothermal validation studies show that the SST k– ω model is slightly better at predicting the wall confluent jets than the other two models. The SST k– ω model is used to investigate the effects of the nozzle diameter, number of nozzles, nozzle array configuration, and inlet discharge height on the ventilation performance of the proposed wall confluent jets supply device. The nozzle diameter and number of nozzles play important roles in determining the airflow pattern, temperature field, and draught distribution. Increased temperature stratification and less draught distribution are achieved by increasing the nozzle diameter and number of nozzles. The supply device with smaller nozzle diameters and fewer nozzles yields rather uniform temperature distribution due to the dominant effect of mixing. The flow behavior is nearly independent of the inlet discharge height for the studied range.

    The proposed wall confluent jets supply device is compared with a mixing supply device, impinging supply device and displacement supply device. The results show that the proposed wall confluent jets supply device has the combined behavior of both mixing and stratification principles. The proposed wall confluent jets supply device provides better overall ventilation performance than the mixing and displacement supply devices used in this study.

    This study covers also another application of confluent jets that is based on impinging technology. The supply device under consideration has an array of round jets on a curve. Multiple jets issue from the supply device aperture, in which the supply device is positioned vertically and the jets are directed against a target wall. The flow behavior and ventilation performance of the impinging confluent jets supply device is studied experimentally in an industrial premise. The results show that the impinging confluent jets supply device maintains acceptable thermal comfort in the occupied zone by creating well-distributed airflow during cold and hot seasons.

  • 93.
    Janbakhsh, Setareh
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Moshfegh, Bahram
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för energi- och maskinteknik.
    Experimental investigation of a new supply diffuser in an office room2009Conference paper (Refereed)
  • 94.
    Janbakhsh, Setareh
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Linköpings universitet.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Linköpings universitet.
    Investigation of design parameters for an air supply device based on wall confluent jets2015Article in journal (Other academic)
  • 95.
    Janbakhsh, Setareh
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Linköping University, Department of Management and Engineering, Division of Energy Systems, Sweden.
    Moshfegh, Bahram
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Linköping University, Department of Management and Engineering, Division of Energy Systems, Sweden.
    Ghahremanian, Shahriar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy engineering. Linköping University, Department of Management and Engineering, Division of Energy Systems, Sweden.
    A Newly Designed Supply Diffuser for Industrial Premises2010In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 9, no 1, p. 59-67Article in journal (Refereed)
    Abstract [en]

    The results of this investigation revealed the airflow distribution from a new design of supply diffuser under non-isothermal conditions. To illustrate the indoor climate parameters in the occupied zone, for both the heating and cooling seasons, an experimental investigation was carried out in industrial premises. The indoor climate was explored at ankle, waist and neck levels for a standing person at different positions, to determine the variation of the thermal comfort indexes and draught rating (DR) with position in the facility. The observed PPD and DR values indicate acceptable levels of thermal comfort in the facility for both summer and winter cases. The conclusion can be drawn that well-distributed airflow saves energy by removing the need for an additional heating and cooling systems during cold and hot weather seasons.

  • 96.
    Jayasekara, Buddhika
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    ASSESSMENT OF DESALINATION NEEDS AND APPROPRIATE TECHNOLGIES FOR SRI LANKA2017Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This study investigates the desalination needs and available technologies in Sri Lanka. Lack of rainfall, pollution due to agricultural chemicals, presence of fluoride, increasing demand, exploitation of ground water and brackishness have created scarcity of fresh pure water specially in near costal and dry zones in Sri Lanka. Due to Cronic Kidney Disease (CKD) around 500 people died in dry zones annually which is suspected to cause by Arsenic and Cadmium contain in ground water due to agriculture chemicals.

     

    The available desalination methods are Reverse Osmosis (RO), Solar distillation and conventional methods. The cost for RO is Rs.0.10 cents per liter and solar distillation Rs.2.96 per liter. Although the price shows that the RO is better but due to high initial investment as a third world country it is very difficult to afford huge initial investment without government intervention. The experimental solar desalination units only produce nearly 5liters of potable water per day and directly impacted by availability of solar radiation.

    The energy availability of Sri Lanka and future potable water demand predicted as 2188.3 Mn liters as maximum demand which will be in 2030, therefore by that time the government should have a proper plan to cater the demand and desalination plants need to be planned and built based on the demand of dry zones and specially agriculture areas. 

     The applicability of renewable energy for desalination in local arena was also simulated taking the Delf Reverse Osmosis plant for the simulation. Results show that the optimum design is combination of Solar PV and existing 100kW Diesel generator Set with Battery bank and converter.  

  • 97.
    Jayaweera, Asanka
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy Analysis & Effects on Power Utility of LED's compared to Conventional Bulbs2014Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 98.
    Jia, Gaoxun
    University of Gävle, Faculty of Engineering and Sustainable Development.
    The reasonable ways to reduce heat losses from windows2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The window insulation always plays an important role in building design and thermal comfort, it is one of the main parts needed to be optimized in building envelop. Window insulation is a basic element which can decide the insulation capacity. The large heat loss from the window is the main part of wasting energy, and simultaneously, there is also difficult to explore the new energy source and to improve the current heat generation device efficiency in this energy crisis century. Therefore, building a proper insulated window system is a good approach to keep an acceptable indoor climate as well as to reduce energy use and negative climate effects. On the other hand, there are amounts of old houses and poorly design houses all over the world either in a well developed country or a developing country. Therefore it can form a better atmosphere to optimize the window worldwide. The aim of the thesis is telling the reader what kind of optimization can be done to get better window insulation. This thesis starts with a briefly introduction to give the basic knowledge of heat loss from windows, and then shows the heat loss level in comparison with other parts of building. Afterwards it gives the optimization strategy to make good window glazing and window frames. For frame design, the hollow frame material property and the benefits of insulants filling window system are described. There are still some problems which exist for the energy efficient windows, such as condensation problem. The thesis also shows this kind of problem and the solution approach.

  • 99.
    Johansson, Maria T.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Linköping University.
    Improved energy efficiency within the Swedish steel industry: the importance of energy management and networking2015In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 8, no 4, p. 713-744Article in journal (Refereed)
    Abstract [en]

    The iron and steel industry is an energy-intensive industry that consumes a significant portion of fossil fuel and electricity production. Climate change, the threat of an unsecure energy supply and rising energy prices have emphasised the issue of improved energy efficiency in the iron and steel industry. However, an energy-efficiency gap is well recognised, i.e. cost-efficient measures are not implemented in practice. This study will go deeper into why this gap occurs by investigating energy-management practices at 11 iron and steel companies in Sweden. Energy managers at the steel plants were interviewed about how they perceived their own and their companies’ efforts to improve energy efficiency and how networking among energy managers influenced the efforts to improve energy efficiency. Reported barriers to improved energy efficiency were, for example, too long payback period, lack of profitability, lack of personnel, risk of production disruption, lack of time and lack of commitment. Only three out of the eleven companies had assigned a person to work full time with energy management, and some of the energy managers were frustrated with not having enough time to work with energy issues. Generally, the respondents felt that they had support from senior management and that energy issues were prioritised, but only a few of the companies had made great efforts to involve employees in improving energy efficiency. Networking among Swedish steel companies was administered by the Swedish Steel Producers’ Association, and their networking meetings contributed to the exchange of knowledge and ideas. In conclusion, Swedish steel companies regard improved energy efficiency as important but have much work left to do in this area. For example, vast amounts of excess heat are not being recovered and more efforts could be put into engaging employees and introducing a culture of energy efficiency.

  • 100.
    Johansson, Maria T.
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system. Linköping University.
    Söderström, Mats
    Electricity generation from low-temperature industrial excess heat: an opportunity for the steel industry2014In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478, Vol. 7, no 2, p. 203-215Article in journal (Refereed)
    Abstract [en]

    Awareness of climate change and the threat of rising energy prices have resulted in increased attention being paid to energy issues and industry seeing a cost benefit in using more energy-efficient production processes. One energy-efficient measure is the recovery of industrial excess heat. However, this option has not been fully investigated and some of the technologies for recovery of excess heat are not yet commercially available. This paper proposes three technologies for the generation of electricity from low-temperature industrial excess heat. The technologies are thermoelectric generation, organic Rankine cycle and phase change material engine system. The technologies are evaluated in relation to each other, with regard to temperature range of the heat source, conversion efficiency, capacity and economy. Because the technologies use heat of different temperature ranges, there is potential for concurrent implementation of two or more of these technologies. Even if the conversion efficiency of a technology is low, it could be worthwhile to utilise if there is no other use for the excess heat. The iron and steel industry is energy intensive and its production processes are often conducted at high temperatures. As a consequence, large amounts of excess heat are generated. The potential electricity production from low-temperature excess heat at a steel plant was calculated together with the corresponding reduction in global CO2 emissions.

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