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  • 101.
    Djuric Ilic, Danica
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Dotzauer, Erik
    School of Sustainable Development of Society and Technology, Mälardalen University, Västerås, Sweden.
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Broman, Göran
    Department of Strategic Sustainable Development, School of Engineering, Blekinge Institute of Technology, Karlskrona, Sweden.
    Integration of biofuel production into district heating – Part II: an evaluation of the district heating production costs using Stockholm as a case study2014Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 69, s. 188-198Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biofuel production through polygeneration with heat as one of the by-products implies a possibility for cooperation between transport and district heating sectors by introducing large-scale biofuel production into district heating systems. The cooperation may have effects on both the biofuel production costs and the district heating production costs. This paper is the second part of the study that investigates those effects. The biofuel production costs evaluation, considering heat and electricity as by-products, was performed in the first part of the study. In this second part of the study, an evaluation of how such cooperation would influence the district heating production costs using Stockholm's district heating system as a case study was performed. The plants introduced in the district heating system were chosen depending on the future development of the transport sector. In order to perform sensitivity analyses of different energy market conditions, two energy market scenarios were applied.

    Despite the higher revenues from the sale of by-products, due to the capital intense investments required, the introduction of large-scale biofuel production into the district heating system does not guarantee economic benefits. Profitability is highly dependent on the types of biofuel production plants and energy market scenarios. The results show that large-scale biogas and ethanol production may lead to a significant reduction in the district heating production costs in both energy market scenarios, especially if support for transportation fuel produced from renewable energy sources is included. If the total biomass capacity of the biofuel production plants introduced into the district heating system is 900 MW, the district heating production costs would be negative and the whole public transport sector and more than 50% of the private cars in the region could be run on the ethanol and biogas produced. The profitability is shown to be lower if the raw biogas that is by-produced in the biofuel production plants is used for combined and power production instead of being sold as transportation fuel; however, this strategy may still result in profitability if the support for transportation fuel produced from renewable energy sources is included. Investments in Fischer–Tropsch diesel and dimethyl ether production are competitive to the investments in combined and power production only if high support for transportation fuel produced from renewable energy sources is included.

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  • 102.
    Djuric Ilic, Danica
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Dotzauer, Erik
    Mälardalen University, Västerås, Sweden.
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Broman, Göran
    Blekinge Institute of Technology, Karlskrona, Sweden.
    Introduction of large-scale biofuel production in a district heating system - an opportunity for reduction of global greenhouse gas emissions2014Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 64, s. 552-561Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, cooperation between Stockholm's transport and district heating sectors is analysed. The cooperation concerns the integration of biofuel polygeneration production. A MODEST optimisation model framework is used, assuming various energy market and transport sector scenarios for the year 2030. The scenarios with biofuel production and increased biofuel use in the region are compared with reference scenarios where all new plants introduced into the district heating sector are combined heat and power plants, and the share of biofuel used in the transport sector is the same as today. The results show that the cooperation implies an opportunity to reduce fossil fuel consumption in the sectors by between 20% and 65%, depending on energy market conditions and assumed transport sector scenarios. If we consider biomass an unlimited resource, the potential for greenhouse gas emissions reduction is significant. However, considering that biomass is a limited resource, the increase of biomass use in the district heating system may lead to a decrease of biomass use in other energy systems. The potential for reduction of global greenhouse gas emissions is thus highly dependent on the alternative use of biomass. If this alternative is used for co-firing in coal condensing power plants, biomass use in combined heat and power plants would be more desirable than biofuel production through polygeneration. On the other hand, if this alternative is used for traditional biofuel production (without co-production of heat and electricity), the benefits of biofuel production through polygeneration from a greenhouse gas emissions perspective is superior. However, if carbon capture and storage technology is applied on the biofuel polygeneration plants, the introduction of large-scale biofuel production into the district heating system would result in a reduction of global greenhouse gas emissions independent of the assumed alternative use of biomass.

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  • 103.
    Djuric Ilic, Danica
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Eriksson, Ola
    Univ Gavle, Sweden.
    Ödlund, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Åberg, Magnus
    Uppsala Univ, Sweden.
    No zero burden assumption in a circular economy2018Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 182, s. 352-362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A majority of previous studies on environmental problems caused by waste generation have focused on waste disposal issues without fully highlighting the primary reasons behind the problems. As a consequence, efforts to reduce these problems are usually directed towards the stakeholders that provide waste treatment and disposal instead of the stakeholders that contribute to waste generation. In order to detect connections between different problems of sustainability and to suggest measures which may contribute to their solutions, this study provides a simplified overview of the mechanisms behind waste generation and management. The results from the study show that the only way to eliminate problems of sustainability is to apply an upstream approach by dealing with the primary problems which occur in the early stages of the system (e.g. overconsumption of products, as well as use of finite resources, toxic materials, and non-recyclable materials). By dealing with these problems, the emergence of secondary problems would be prevented. Thereby, stakeholders who have the highest possibility to contribute to the sustainable development of the waste generation and management are the stakeholders from the origin of the products life cycles, such as product developers, manufacturing companies, product users and policy makers. Different trade-off situations such as contradictions between economics, recyclability, energy efficiency, make it even harder to deal with issues of sustainability related to the system and to detect the stakeholders who may contribute to the development. One of the main conclusions from this study is that when transforming society towards a circular economy, the traditional view of separate systems for production and waste management must be changed. In order to refer to all problems of sustainability and also cover the top steps of the waste hierarchy, life cycle assessment of waste management should include manufacture and use of products ending up as waste. Waste entering the waste management system with "zero burden", by releasing the previous actors of the waste life cycle from any responsibility related to the environment (i.e. by shifting the total environmental burden into the waste management system), does not capture the problems with waste generation. (C) 2018 Elsevier Ltd. All rights reserved.

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  • 104.
    Djuric Ilic, Danica
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Henriksson, Malin
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Magnusson, Dick
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Stockholms fjärrvärmenät idag och imorgon: en tvärvetenskaplig studie av ett regionalt energisystem2009Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Fjärrvärme spelar en viktig roll i strävan mot ett hållbart samhälle. Därför har vi i denna studie studerat Stockholms fjärrvärmenät och de aktörer som påverkar dess utformning. Syftet med studien har varit att undersöka drivkrafter och hinder för att utveckla fjärrvärmenäten i Stockholm. Vidare har syftet varit att studera hur aktörerna samverkar på kommunal och regional nivå för att bibehålla och/ eller vidareutveckla energisamarbeten.

    Fjärrvärmenätet har modellerats utifrån sex olika scenarier i optimeringsprogrammet MODEST. Genom scenarierna har vi kunnat testa dagens nät med bättre sammankopplingar, byggande av kraftvärmeverk samt naturgas som bränsle i kraftvärmeverken. Vidare har kvalitativa intervjuer med kommuner, energibolag, intresse- och branschorganisationer samt regionala aktörer genomförts.

    Studien visar att Stockholms fjärrvärmenät redan idag är väl sammankopplat vilket innebär att de ekonomiska vinsterna med ytterligare sammankopplingar inte är särskilt stora. Modelleringarna pekar dock på att byggande av kraftvärme, både med biobränsle och med naturgas, har en viss ekonomisk potential. En positiv effekt är också minskningen av de globala utsläppen av växthusgaser. Vinster med samarbeten och sammankopplingar från energibolagens sida är framförallt ökad driftsäkerhet och driftsoptimering samt möjligheten att samordna revisioner. För att samarbeten ska fungera är dock ekonomisk vinst för samtliga parter samt jämlika förhållanden dem emellan en förutsättning. Det är inte tekniska problem som hindrar utökade sammankopplingar, snarare är det ökat behov av planering och administration som försvårar utökat samarbete mellan bolag.

    Genom resultatet från intervjuerna kan slutsatsen dras att ett glapp finns i synen på samverkan mellan bolag och kommuner. Detta oavsett om bolagen är kommunalt eller privat ägda. Att energibolagen ska drivas på bolagsmässiga grunder kan vara en förklaring till detta. Energiplanering från kommunernas perspektiv har kommit att handla om klimatfrågan i hög utsträckning och ses ofta som synonymt med miljöarbete. Energiplaneringen har därmed fått högre status och flyttats närmre kommunledning. Samtidigt sker energiplanering på många olika nivåer, inom och mellan kommunerna samt på regional nivå, vilket gör det svårt att få ett samlat grepp om frågan. Också bolagen har olika syn på det regionala perspektivet vilket pekar på att det saknas ett fungerande regionalt organ där bolag och kommuner kan samverka.

    Även om både energibolagen och kommunerna är positivt inställda till fjärrvärme som teknik ser framtiden för fjärrvärmebranschen något osäker ut. Minskade värmelaster på grund av energieffektiviseringar och klimatförändringar bidrar till osäkerheten. Samtidigt väntar en utredning om tredjepartstillträde som potentiellt kan innebära stora förändringar för branschen. Genom att alla bygger kraftvärme kan det vara ett sätt att ändra marknadsinriktning från värme till el för att ge ökad lönsamhet. Det går inte heller att bortse från att Stockholmsregionen har goda förutsättningar för att införa ett tredjepartstillträde där kunderna själva kan välja fjärrvärmeleverantör.

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    Stockholms fjärrvärmenät idag och imorgon : en tvärvetenskaplig studie av ett regionalt energisystem
  • 105.
    Djuric Ilic, Danica
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Economic and environmental benefits of converting industrial processes to district heating2014Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 87, s. 305-317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study is to analyse the possibilities of converting production and support processes from electricity and fossil fuels to district heating in 83 manufacturing companies in three different Swedish counties. A tool for heat load analysis called Method for Heat Load Analysis (MeHLA) is used to explore how the conversions would affect the heat load duration curves in local district heating systems. Economic effects and impacts on global emissions of greenhouse gases are studied from a system perspective. The study has been conducted considering two different energy market conditions for the year 2030.

    The results show that there is a potential for increasing industrial district heating use in all analysed counties. When comparing all three counties, the greatest potential regarding percentage is found in Jönköping, where the district heating use in the manufacturing companies could increase by nine times (from 5 GWh to 45 GWh annually). The industrial district heating use could increase by two times (from 84 GWh to 168 GWh annually) in Östergötland and by four times (from 14 GWh to 58 GWh annually) in Västra Götaland. The conversion of the industrial production processes to district heating would lead to a district heating demand curve which is less dependent on outdoor temperature. As a result, the utilization period of the combined heat and power plants would be prolonged, which would decrease district heating production costs due to the increased income from the electricity production.

    In all analysed counties, the energy costs for the companies decrease after the conversions. Furthermore, the increased electricity production in the combined heat and power plants, and the decreased electricity and fossil fuel use in the industrial sector opens up a possibility for a reduction of global greenhouse gas emissions. The potential for the reduction of global greenhouse gas emissions is highly dependent on the alternative use of biomass and on the type of the marginal electricity producers. When the marginal effects from biomass use are not considered, the greenhouse gas emissions reduction is between 10 thousand tonnes of CO2eq and 58 thousand tonnes of CO2eq per year, depending on the county and the type of marginal electricity production plants. The highest reduction is achieved in Östergötland. However, considering that biomass is a limited resource, the increase of biomass use in the district heating systems may lead to a decrease of biomass use in other energy systems. If this assumption is included in the calculations, the conversion of the industrial processes to district heating still signify a  potential for reduction of greenhouse gas emissions, but this potential is considerable lower.

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  • 106.
    Djuric Ilic, Danica
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Introducing of absorption cooling process in CHP systems: an opportunity for reduction of global CO2 emissions2011Ingår i: Proceedings of ECOS 2011 - 24th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, 2011, s. 3105-3116Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The purpose of this research study is to examine the potential for reduction of global CO2 emissions (GECO2) by converting from vapour compression chillers to absorption chillers in Stockholm’s district cooling (DC) system and in Stockholm’s industrial sector. The analysis of the cooling production is made through optimizations in MODEST, a model framework developed for analysis of dynamic energy systems. The results show that more than 95% of the cooling demand that is currently met by compression chillers during the months from April to October should be produced by district heat (DH)-driven absorption cooling chillers in order to lower GECO2. As a consequence of this conversion, the utilization time of the combined heat and power (CHP) plants in Stockholm’s district heating (DH) system would be prolonged and at the same time the electricity used for compression cooling production would be reduced. Assuming coal condensing production as the marginal electricity production in the common electricity market and considering both the increase in electricity production and the reduction in electricity used, the potential for the reduction of GECO2 would be about 0.15 million tonnes annually. Rising cooling demand would make the introduction of absorption technology in the system even more interesting. If the comfort cooling demand in the region increases by 30%, electricity production in the system during the summer would be about 70% higher, which would lead to a reduction of GECO2 by 0.2 million tonnes annually compared with GECO2 today.

  • 107.
    Djuric Ilic, Danica
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Ödlund, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Method for allocation of carbon dioxide emissions from waste incineration which includes energy recovery2018Ingår i: 16TH INTERNATIONAL SYMPOSIUM ON DISTRICT HEATING AND COOLING, DHC2018, ELSEVIER SCIENCE BV , 2018, Vol. 149, s. 400-409Konferensbidrag (Refereegranskat)
    Abstract [en]

    Presently, waste is regarded as any other fuel in the Swedish district heating (DH) plants where it is treated in combination with energy recovery. Consequently, all carbon dioxide (CO2) emissions that occur during waste treatment are allocated to DH producers even though two simultaneous services are provided - waste treatment and energy recovery. As the focus today is on phasing out fossil fuels from Swedish DH sector, energy recovery from waste turns out to be less desirable than heat production using biofuel and renewable electricity. This article discusses whether the existing allocation method of CO2 emissions contributes to sustainable development and if it does not, to recommend a new method that will. To do this type of assessment, we used the principles from Framework for Strategic Sustainable Development. Results showed that the existing allocation method does not consider the problem of waste generation. The method shifts the responsibility from waste producers to DH customers. To prevent this burden shifting, a broader system perspective and an upstream approach should be applied. In addition, the method should be designed in ways that would give incentives to responsible stakeholders to act properly, which requires identifying the reasons why waste is not being recycled and to find a way to apply the allocation. Considering resource efficiency, waste treatment through combustion should always include energy recovery. To encourage energy recovery, the produced heat should not be burdened with CO2 emissions. (C) 2018 The Authors. Published by Elsevier Ltd.

  • 108.
    Ekman, Oskar
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Dynamic pricing and carbon intensity in demand response functions2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den europeiska energisektorn står inför stora utmaningar, bland annat i form av investeringsbehov i nätinfrastruktur och produktionskapacitet för att säkra framtida leveranssäkerhet. Den fortsatta utbyggnaden av intermittent förnybar kraftproduktion ställer också nya krav på nätet och på aktörernas flexibilitet. Smarta nät ses som ett kostnadseffektivt sätt för att övervinna dessa utmaningar genom en mer effektiv användning av nuvarande kapacitet. En viktig del i detta är efterfrågerespons, som syftar till att minska belastningen på nätet under höglasttimmar genom att i högre grad än tidigare involvera konsumenten. De flesta initiativ inom efterfrågerespons har använt dynamisk prissättning för att uppmuntra konsumenter att flytta konsumtion från höglast- till låglasttimmar. I Norra Djurgårdsstaden, där visionen är att bygga ett hållbart och mer flexibelt energisystem, har det föreslagits att dynamisk prissättning bör kompletteras med en indikator som visar den inköpta elens koldioxidintensitet. Denna indikator är baserad på medelel, vilket är ett av två fundamentala sätt att miljövärdera el.

    Syftet med denna studie var att utvärdera om den metod som används för att kvantifiera koldioxidintensiteten i Norra Djurgårdsstaden är lämplig i samband med efterfrågerespons. För att uppnå detta har en litteraturstudie genomförts gällande potentiella fördelar med efterfrågerespons, hur kraftsystemet fungerar samt olika metoder för att miljövärdera el. En kvantitativ analys har också genomförts, där CO2-signalen i Norra Djurgårdsstaden har modellerats utifrån olika tidsperspektiv. Resultaten visar att CO2-signalen i Norra Djurgårdsstaden är konstruerad på ett sådant sätt att den till stor del påverkas av vattenkraftens produktionsvariationer, vilket i sin tur gör att signalen generellt rör sig i motsatt riktning mot prissignalen. Resultatet av detta är att CO2-signalen motverkar många av de långsiktiga fördelarna med efterfrågestyrning. Dessutom ter det sig osannolikt att signalen skulle leda till signifikanta utsläppsminskningar på kort sikt, eftersom lasten i Sverige främst balanseras av variationer i vattenkraft.

    Utifrån litteraturstudien kan man dra slutsatsen att marginalelens koldioxidintensitet skulle vara en lämpligare miljöindikator än genomsnittliga utsläpp i samband med efterfrågestyrning. Det är dock svårt att i praktiken konstruera en styrsignal baserat på detta perspektiv på grund av systemets komplexitet och brist på data. Historiska marginella utsläpp modellerades emellertid med hjälp av linjär regression. Resultaten från detta indikerade att priset kan vara en tillräcklig indikator även för variationerna i koldioxidintensitet utifrån ett marginalperspektiv.

    Slutligen föreslås en modell för en signal baserad på dagenföreprognoser om intermittent förnybar produktion, där budskapet skulle vara att användaren minskar sin konsumtion under timmar med låg förnybar produktion. Denna signal modellerades med hjälp av uppgifter om förnybar produktion från Danmark eftersom motsvarande uppgifter om Svensk produktion inte finns tillgängliga ännu. Resultaten visar att det skulle vara möjligt att konstruera en relativt träffsäker styrsignal på detta sätt. Det finns också skäl att tro att efterfrågerespons baserat på denna typ av signal skulle leda till miljömässiga fördelar på längre sikt. 

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    Dynamic pricing and carbon intensity in demand response functions
  • 109.
    Elez, Stefan
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Framtida energilösning för tillvaratagande av överskottsvärme med värmepump: Ett examensarbete utfört på Händelöverket, E.ON2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    E.ON har satt som mål att leverera 100% förnybar och återvunnen energi år 2025. På E.ON:s kraftvärmeverk Händelö i Norrköping måste då den koldrivna Panna 12, men även den biodrivna Panna 11 ersättas med en ny typ av förnybar och återvunnen lösning som ska producera värme. En lösning som diskuteras på E.ON är att ersätta dessa två pannor med en biohetvattenpanna, Panna 16. I Händelöområdet finns dock en del verksamheter med restflöden i form av överskottsvärme som i nuläget inte tas vara på. Genom utnyttjande av överskottsvärme kan växthuseffekten minskas och det nationella energisystemet effektiviseras. En ytterligare lösning skulle därför kunna vara att ersätta pannorna med en energilösning som utnyttjar överskottsvärme och med hjälp av värmepump producerar värme.

    Syftet med det här projektet har därför varit att undersöka möjligheterna för en framtida energilösning med värmepump och hur den kan användas i samverkan med Händelöverket för att minska investerings-och marginalkostnaderna för värmeproduktionen till Norrköpings fjärrvärmenät. Målet med projektet har därför varit att ta fram en modell i modelleringsverktyget reMind och VBA Excel som kan beräkna lönsamheten för den framtida värmepumpslösningen gentemot den nya Panna 16 med olika scenarier för elpriser.

    Under projektet har en dimensionering av en kompressordriven värmepump utförts för att ta reda på de tekniska och driftmässiga förutsättningarna för en värmepump. Sedan har olika modeller gjorts i reMind och VBA Excel för en kompressordriven värmepump och en absorptionsvärmepump. Absorptionsvärmepumpen har inte dimensionerats under projektet, utan där har olika värden relaterade till de tekniska-och driftmässiga förutsättningarna erhållits från en värmepumpsleverantör.

    Resultatet visar att en energilösning med absorptionsvärmepump är betydligt mer lönsam än en lösning med enbart Panna 16. Absorptionsvärmepumpen blev 30

    – 42 MSEK billigare i investering gentemot Panna 16. Dessutom blev absorptionsvärmepumpen 79 – 102 MSEK mer lönsam med en ekonomisk livslängd på 20 för de olika elprisscenarierna. Totalt sett blev det en lönsamhet på ca 110 – 140 MSEK gentemot Panna 16. Den kompressordrivna värmepumpen blev å andra sidan inte lönsam i jämförelse med Panna 16. Investeringskostnaden för den kompressordrivna värmepumpen blev 14 – 24 MSEK dyrare än Panna 16:s motsvarande investeringskostnad och skillnaden i marginalkostnad hamnade endast i intervallet 0 – 5 MSEK med olika elprisscenarion.

    Slutsatsen blev att E.ON ska fortsätta att utreda möjligheterna med att eventuellt investera i en absorptionsvärmepump. För den kompressordrivna värmepumpen anses det dock inte vara värt att undersöka vidare.

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    Energilösning värmepump
  • 110.
    Ellegård, Kajsa
    et al.
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Thoresson, Josefin
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Rohdin, Patrik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Filosofiska fakulteten.
    Tid för brukarengagemang2014Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Det går åt mycket energi i offentliga lokaler; förvaltningar, skolor, vård- och omsorgsboenden, sjukhus med mera. Små förändringar som minskar energiåtgången ger sammantaget stora resultat när de görs av många människor. Det finns mycket att spara, både i skattepengar och miljö. För att det ska bli möjligt krävs att personalen som arbetar i lokalerna får den tid och kunskap som behövs för att de ska kunna engagera sig i miljö- och energisparfrågor. Denna skrift handlar om förutsättningarna för att engagera brukarna i de offentliga fastighetsorganisationernas energieffektiviseringsarbete.

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  • 111.
    Elvemo, Kristian
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Kapacitetsanalys av CFB-pannan vid SCA Packaging Munksund AB2009Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Kraftvärmeverket vid SCA Packaging Munksund AB är ett samarbete mellan SCA och Vattenfall och det består av en ångpanna av typen cirkulerande fluidiserad bädd som togs i drift 2001. Man vill nu genomföra en undersökning om CFBpannans prestanda har förändrats sedan starten, samt en undersökning av pannans maximala kapacitet. Examensarbetet har då bestått av att utföra ett prestandaprov samt ett prov för maximal kapacitet. Arbetet har även innefattat att utarbeta en algoritm för att fiktivt beräkna ingående bränslets fukthalt via rökgasparametrar.

    CFB-pannan är dimensionerad mot en termisk effekt på 98MW, vid en bränslekvalitet på 55 % fukthalt och värmevärdet 7,3 MJ/kg. Vid denna driftpunkt garanterar panntillverkaren Foster Wheeler en verkningsgrad på minst 90,57 %. Prestandaprovet från 2002 visade på en verkningsgrad på 91,1 %. Resultatet från dessa observationer visade på en verkningsgrad på 92,07 %, att notera är att bränslekvaliteten legat på fukthalten 50 % och värmevärdet 8,48 MJ/kg.

    Vid framtida produktionsökningar i pappersbruket kommer man samtidigt behöva öka produktionen av processånga. Man har sedan tidigare drifterfarenheter påpekat att man har haft problem med pannans luft/rökgassytem vid höga laster. Resultatet från maxkapacitetstesterna var att pannan primärt begränsas av kvaliteten på bränslet, då detta sätter en begränsning på hur mycket energi som finns tillgängligt. Processmässigt så blev resultatet att motorn till rökgasfläkten samt sandåterföringen var de begränsande enheterna. Vid testet var bränslefukthalten 45 % och man uppnådde då ett ångflöde på 146 ton/h. Det kom även fram att sekundärfläkten inte körts enligt panntillverkarens rekommenderade motorhastighet på 1765 varv/min, den aktuella inställningen har ett synkront varvtal på 1500 varv/min.

    Att utreda hur mycket effekt som dessa begränsningar låser fast har varit oerhört svårt att ge svar på, och vad gäller tidsramen för arbetet så har det inte kunnat grävas djupare i denna problemställning. En teoretisk analys har däremot utförts på maximal kapacitet vid olika bränslefukthalter, se Figur 33 och Figur 34 på sidan 78. Dessa figurer belyser hur viktig kvaliteten på bränslet är för att pannan skall kunna ha en möjlighet att leverera en hög last. Då hanteringen av bränslet för att minimera kvalitetsförluster är något man kan påverka med enklare metoder, är rekommendationen att man startar en projektgrupp som ser över bränslehanteringen för att minimera kvalitetsförluster vid egen kortvarig lagring.

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  • 112.
    Eriksson, Marcus
    et al.
    Chalmers, Göteborg.
    Hrelja, Robert
    Linköpings universitet, Institutionen för tema. Linköpings universitet, Filosofiska fakulteten.
    Lindmark, Susanne
    Kungliga tekniska högskolan, Stockholm.
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Förändrade randvillkor för kommunala energisystem: påverkan och effekter2003Rapport (Övrigt vetenskapligt)
  • 113.
    Eriksson, Martin
    et al.
    Univ Gavle, Sweden.
    Akander, Jan
    Univ Gavle, Sweden.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten. Univ Gavle, Sweden.
    Development and validation of energy signature method - Case study on a multi-family building in Sweden before and after deep renovation2020Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 210, artikel-id UNSP 109756Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Building energy use constitutes a large part of total energy use, both in the European Union and Sweden. Due to this energy use, and the resulting emissions, several goals for energy efficiency and emissions have been set. In Sweden, a large portion of multi-family buildings were built between 1960 and 1980, which have major energy savings potential. The purpose of this paper is further development and validation of previously introduced energy signature method and its inherent parameters. The method was applied on a multi-family building where thermal energy data supplied by the district heating company was available before and after deep renovation. Using IDA ICE, a building energy simulation (BES) software model was created of the building, to aid in validation of the energy signature method. The paper highlighted the accuracy of the proposed energy signature (PES) method and a sensitivity analysis on the inherent parameters have been performed. The results showed new ways of treatment of the thermal energy data and revealed how more information can be extracted from this data. (C) 2020 The Authors. Published by Elsevier B.V.

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  • 114.
    Fahlen, Elsa
    et al.
    Chalmers, Sweden .
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Ahlgren, Erik O
    Chalmers, Sweden .
    Assessment of absorption cooling as a district heating system strategy - A case study2012Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 60, nr SI, s. 115-124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heat load variations, daily as well as seasonal, are constraining co-generation of high-value energy products as well as excess heat utilisation. Integration of heat-driven absorption cooling (AC) technology in a district heating and cooling (DHC) system raises the district heat (DH) demand during low-demand periods and may thus contribute to a more efficient resource utilisation. In Sweden, AC expansion is a potentially interesting option since the cooling demand is rapidly increasing, albeit from low levels, and DH systems cover most of the areas with potential cooling demand. This study aims to assess the potential for cost and CO2 emission reduction due to expansion of DH-driven AC instead of electricity-driven compression cooling in the DHC system of Goteborg, characterised by a high share of low-cost excess heat sources. The DHC production is simulated on an hourly basis using the least-cost model MARTES. Despite recent advances of compression chillers, the results show potential for cost-effective CO2 emission reduction by AC expansion, which is robust with regards to the different scenarios applied of energy market prices and policies. While the effects on annual DHC system results are minor, the study illustrates that an increased cooling demand may be met by generation associated with low or even negative net CO2 emissions - as long as there is high availability of industrial excess heat in the DHC system, or if e.g. new biomass-based combined heat and power capacity is installed, due to the avoided and replaced marginal power generation.

  • 115.
    Falk, Karolina
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Forsberg, Joel
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Adapting to the Changes Enforced by EU’s Network Codes for Electricity: The Consequences for an Electricity Company from a Distribution System Operator’s Perspective2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    To reach EU’s climate and energy target an integrated electricity market is considered to be required (Klessmann, et al., 2011; Boie, et al., 2014; Becker, et al., 2013). As a result the European Commission decided to form a set of rules, named the Network Codes, to create a single European market (ENTSO-E, 2013b). The Network Codes will affect Distribution- and Transmission System Operators, grid users and production units as well as all the other actors on the electricity market (Eurelectric, n.d.a). Concerns regarding what the Network Codes’ actual consequences are have been expressed within the line of business (Swedish Energy, 2013a). Therefore the purpose of this master’s thesis was to determine and furthermore illustrate the consequences the Network Codes will have, in current version, for a Swedish non-transmission system connected electricity company and determine what actions need to be taken.

    The purpose has been addressed by conducting interviews, document studies and by utilizing a change management model, the Intervention Strategy Model, introduced by Paton & McCalman (2000). The structured approach that is the nature of the model was used when determining the consequences the Network Codes enforce and what actions a non-transmission system connected electricity company has to take to cope with them. To further facilitate the determination of these actions this study was conducted on a non-transmission system connected electricity company, in this thesis named Electricity Company A.

    The investigation of the concerns expressed within the line of business illustrated that the concerns were diverse but a majority of them might be incorporated into either of the following groups, simulation models, demand side aggregator and information handling. Out of these groups information handling was by far the area of greatest concern with issues primarily connected to the Distribution System Operator. Consequently this thesis focused on the Distribution System Operator’s perspective.

    The analysis of the area of greatest concern, presented in two flow charts, clearly showed the increased amount of communication enforced by the Network Codes. This increased information handling results in numerous possible organisational consequences for the Distribution System Operator, for example might new systems be required and some existing systems be used with or without adaption. Furthermore, the extra workload could possibly be handled by the existing personnel, in some cases after complementary education, but it might also require new personnel. Finally the Network Codes open up for the possibility for the Distribution System Operator to define certain details which may be conducted individually or in cooperation with other Distribution System Operators. Which of these possible consequences that will affect a specific company is, however, dependent on its preconditions.

    The study on Electricity Company A reveals that the numerous actions required to handle the new communication were not as significant as the line of business might have feared. For Electricity Company A, primarily a new system is needed to handle the real-time values and some of the existing systems need to be updated. Additionally the combined extra work load might require extra personnel for Electricity Company A even though the individual work assignments are fairly small. The actions required should be fairly similar for companies of approximately equal size but might be more extensive for smaller non-transmission system connected electricity companies. All companies need, however, to conduct an individual analysis to determine which specific actions are required for them.

    The conclusions of this thesis aspired, and partly succeeded, to be generalizable on a European level. One example of this is the usage of the Intervention Strategy Model which proved applicable for determining which specific actions are required for all European electricity companies. Furthermore the concerns presented and the possible consequences of the increased information handling found, are generalizable but not complete for all European electricity companies. This thesis focused on one part of the complex Network Codes’ consequences and consequently further research is needed to fully understand the consequences for the electricity business in total.

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    Adapting to the Changes Enforced by EU’s Network Codes for Electricity - Falk & Forsberg
  • 116.
    Fallde, Magdalena
    et al.
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring.
    Flink, Mimmi
    Energy processes, KTH (Royal Institute of Technology).
    Lindfeldt, Erik
    Energy processes, KTH (Royal Institute of Technology).
    Pettersson, Karin
    Heat and Power Technology, Chalmers University of Technology.
    Wetterlund, Elisabeth
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Bakom drivmedelstanken - Perspektiv på svenska biodrivmedelssatsningar2007Rapport (Övrigt vetenskapligt)
  • 117.
    Feiz Aghaei, Roozbeh
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Maria
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Lindkvist, Emma
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Moestedt, Jan
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Tekniska Verken and Linkoping AB Publ, Dept Technol and Syst, Box 1500, SE-58183 Linkoping, Sweden.
    Nilsson Paledal, Sören
    Linköpings universitet, Biogas Research Center. Tekniska Verken and Linkoping AB Publ, Dept Technol and Syst, Box 1500, SE-58183 Linkoping, Sweden.
    Svensson, Niclas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Key performance indicators for biogas production-methodological insights on the life-cycle analysis of biogas production from source-separated food waste2020Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 200, artikel-id 117462Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The anaerobic digestion of food waste can not only enhance the treatment of organic wastes, but also contributes to renewable energy production and the recirculation of nutrients. These multiple benefits are among the main reasons for the expansion of biogas production from food waste in many countries. We present methodological insights and recommendations on assessing the environmental and economic performance of these systems from a life-cycle perspective. We provide a taxonomy of the value chain of biogas from food waste which describes major activities, flows, and parameters across the value chain with a relatively high detail. By considering the multiple functions of biogas production from food waste, we propose a few key performance indicators (KPI) to allow comparison of different biogas production systems from the perspectives of climate impact, primary energy use, nutrients recycling, and cost. We demonstrate the operational use of our method through an example, where alternatives regarding the heat supply of the biogas plant are investigated. We demonstrate how global and local sensitivity analyses can be combined with the suggested taxonomy and KPIs for uncertainty management and additional analyses. The KPIs provide useful input into decision-making processes regarding the future development of biogas solutions from food waste. (C) 2020 Elsevier Ltd. All rights reserved.

  • 118.
    Feiz, Roozbeh
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Biogas Research Center. Biogas Research Center.
    Ammenberg, Jonas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Björn, Annika
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Yufang, Guo
    School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China.
    Karlsson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Liu, Yonghui
    School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China.
    Liu, Yuxian
    Linköpings universitet. Guangzhou University Research Center on Urban Sustainable Development, Guangzhou University, Guangzhou, China.
    Masuda, Laura Shizue Moriga
    Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
    Enrich-Prast, Alex
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Rohracher, Harald
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Trygg, Kristina
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Shakeri Yekta, Sepehr
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Zhang, Fagen
    School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China.
    Biogas Potential for Improved Sustainability in Guangzhou, China: A Study Focusing on Food Waste on Xiaoguwei Island2019Ingår i: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, nr 6Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As a result of rapid development in China and the growth of megacities, large amounts of organic wastes are generated within relatively small areas. Part of these wastes can be used to produce biogas, not only to reduce waste-related problems, but also to provide renewable energy, recycle nutrients, and lower greenhouse gases and air polluting emissions. This article is focused on the conditions for biogas solutions in Guangzhou. It is based on a transdisciplinary project that integrates several approaches, for example, literature studies and lab analysis of food waste to estimate the food waste potential, interviews to learn about the socio-technical context and conditions, and life-cycle assessment to investigate the performance of different waste management scenarios involving biogas production. Xiaoguwei Island, with a population of about 250,000 people, was chosen as the area of study. The results show that there are significant food waste potentials on the island, and that all studied scenarios could contribute to a net reduction of greenhouse gas emissions. Several socio-technical barriers were identified, but it is expected that the forthcoming regulatory changes help to overcome some of them.

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  • 119.
    Fenton, Paul David
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Sara
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Ivner, Jenny
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Palm, Jenny
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Stakeholder participation in municipal energy and climate planning – experiences from Sweden2016Ingår i: Local Environment: the International Journal of Justice and Sustainability, ISSN 1354-9839, E-ISSN 1469-6711, Vol. 21, nr 3, s. 272-289Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article analyses the factors influencing stakeholder participation in municipal energy and climate planning, together with stakeholder experiences of participation in such processes. The article presents findings from a survey of 60 Swedish municipalities and detailed case studies of energy and climate planning in five Swedish municipalities to explore which stakeholders are involved, how and why they are involved, and the impacts of participation on both stakeholder experiences. The results of this study provide insight into the role of stakeholders in municipal energy and climate planning.The study proceeds as follows: the Introduction is followed by a discussion of theoretical perspectives on stakeholder participation and energy and climate planning. The Methods used to conduct the study are presented, followed by Results and Analysis. In the subsequent Discussion, the authors propose a conceptual approach that may assist municipalities in development of energy and climate strategies. The Analysis and Discussion inform Conclusions in which the authors advocate early and active stakeholder engagement in energy and climate strategy planning and emphasise the possible utility of their conceptual approach in supporting stakeholder participation.

  • 120.
    Fenton, Paul David
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Sara
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Ivner, Jenny
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Palm, Jenny
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Sustainable energy and climate strategies: lessons from planning processes in five Swedish municipalities2015Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 98, s. 213-221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Swedish municipalities have traditionally had significant powers and played a major role in implementing national energy strategies. This paper describes the factors influencing development of municipal climate and energy plans in five Swedish municipalities and assesses the relevance and importance of these factors from theoretical and practical perspectives. The questions raised in the paper are: what are the characteristics of municipal climate and energy planning processes in the five municipalities, do these municipalities include stakeholders in the process, if so how, and do the stakeholders influence the content of strategies? Results suggest that a number of factors influence the development of municipal climate and energy strategies and their content. These include the importance of a clear, shared vision and engaged politicians; the size and organisational structure of the municipality and its willingness and capability to act; the organisation of the process and extent to which stakeholders not only have been involved but also felt included; the need for clarity about financial aspects, such as planned financing of implementation; and the need for greater clarity concerning selection of targets and their relevance to global climate and energy trends. The study and its results may be used to inform policy-makers on the national and local levels about factors influencing municipal energy planning and also contribute to a discussion on benefits and problems of involving stakeholders and citizens in the strategic work to reduce climate impacts and energy consumption.

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  • 121.
    Fjellborg, Anders
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Energieffektiv ventilation2012Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med detta examensarbete är att konkretisera och visa på de grundläggande problemen med inomhusklimatet i Brogårdsfabriken i Vetlanda, för att utifrån detta komma fram med åtgärdsförslag för att minska dem. Detta samt att utreda möjligheterna att ta till vara den i fabriken internt genererade överskottsvärmen och minska energianvändningen.

    Arbetet har skett i ett top-down-perspektiv, vilket betyder att fabriken ses som ett slutet system där tillförd energi in i systemet ställs mot bortförd energi ut ur systemet. Stor del av arbetet har bedrivits i simuleringsprogrammet IDA – Indoor Climate and Energy till vilket data samlats in genom fysiska mätningar i fabriken och genom intern dokumentation på företaget.

    Problemen med inomhusklimatet för de anställda ute i produktionen är av olika karaktär i olika delar av fabriken och varierar även i intensitet beroende på vilken tid på året som studeras. Dock är de bakomliggande orsakerna till problemen alltid desamma. Det handlar bland annat om bristfällig processventilation, stora öppna lokaler som är svårkontrollerade, problem med infiltration genom portar och andra öppningar i klimatskalet.

    Förslag att återskapa en tidigare befintlig vägg rekommenderas för att lösa problemet med kalldrag i packhallen. Väggen skulle förhindra luftrörelser i områden där problemen upplevs och nästintill eliminera dem.

    Fokus på att minska energianvändningen har skett genom att titta på en optimering av ventilationsdriften vilket har resulterat i en kostnadsbesparing på cirka 370 tkr/år vid reducering av driften under enbart helger. Det finns ytterligare potential till kostnadsbesparingar för ventilationsdriften under andra tillfälliga driftstopp eller semesterstängningar av fabriken, om ventilationsdriften anpassas efter detta.

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  • 122.
    Flink, Mimmi
    et al.
    Energy Processes, KTH (Royal Institute of Technology).
    Pettersson, Karin
    Heat and Power Technology, Chalmers University of Technology.
    Wetterlund, Elisabeth
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Comparing new Swedish concepts for production of second generation biofuels - evaluating CO2 emissions using a system approach2007Ingår i: SETAC Europe 14th LCA Case Studies Symposium, 3-4 december 2007, Göteborg, Sweden, 2007Konferensbidrag (Övrigt vetenskapligt)
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    FULLTEXT01
  • 123.
    Forsberg, Jimmy
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Nilsson, Lars
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Topology optimization in crashworthiness design2007Ingår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 33, nr 1, s. 1-12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Topology optimization has developed rapidly, primarily with application on linear elastic structures subjected to static loadcases. In its basic form, an approximated optimization problem is formulated using analytical or semi-analytical methods to perform the sensitivity analysis. When an explicit finite element method is used to solve contact–impact problems, the sensitivities cannot easily be found. Hence, the engineer is forced to use numerical derivatives or other approaches. Since each finite element simulation of an impact problem may take days of computing time, the sensitivity-based methods are not a useful approach. Therefore, two alternative formulations for topology optimization are investigated in this work. The fundamental approach is to remove elements or, alternatively, change the element thicknesses based on the internal energy density distribution in the model. There is no automatic shift between the two methods within the existing algorithm. Within this formulation, it is possible to treat nonlinear effects, e.g., contact–impact and plasticity. Since no sensitivities are used, the updated design might be a step in the wrong direction for some finite elements. The load paths within the model will change if elements are removed or the element thicknesses are altered. Therefore, care should be taken with this procedure so that small steps are used, i.e., the change of the model should not be too large between two successive iterations and, therefore, the design parameters should not be altered too much. It is shown in this paper that the proposed method for topology optimization of a nonlinear problem gives similar result as a standard topology optimization procedures for the linear elastic case. Furthermore, the proposed procedures allow for topology optimization of nonlinear problems. The major restriction of the method is that responses in the optimization formulation must be coupled to the thickness updating procedure, e.g., constraint on a nodal displacement, acceleration level that is allowed.

  • 124.
    Franzén, Ida
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Nedar, Linnéa
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Andersson, Maria
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Environmental Comparison of Energy Solutions for Heating and Cooling2019Ingår i: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, nr 24, artikel-id 7051Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Humanity faces several environmental challenges today. The planet has limited resources, and it is necessary to use these resources effectively. This paper examines the environmental impact of three energy solutions for the heating and cooling of buildings. The solutions are conventional district heating and cooling, a smart energy solution for heating and cooling (ectogrid™), and geothermal energy. The ectogrid™ balances energy flows with higher and lower temperatures to reduce the need for supplied energy. The three solutions have been studied for Medicon Village, which is a district in the city of Lund in Sweden. The study shows that the energy use for the conventional system is 12,250 MWh for one year, and emissions are 590 tons of CO2 equivalents. With ectogrid™, the energy use is reduced by 61%, and the emissions are reduced by 12%, compared to the conventional system. With geothermal energy, the energy use is reduced by 70%, and the emissions by 20%. An analysis is also made in a European context, with heating based on natural gas and cooling based on air conditioners. The study shows that the environmental impact would decrease considerably by replacing the carbon dioxide intensive solution with ectogrid™ or geothermal energy.

    Ladda ner fulltext (pdf)
    fulltext
  • 125.
    Fuller, Robert
    et al.
    Deakin University, Geelong, Victoria, Australia.
    Thollander, Patrik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Lessons from the greenest city2013Ingår i: Proceedings of the 2013 Urban Design Conference, Nerang, Qld. Australia, 2013, s. 54-61Konferensbidrag (Refereegranskat)
    Abstract [en]

    In 2007, the City of Växjö in Sweden was voted the greenest city in Europe. Over an 18-year period, greenhouse gas emissions per resident have been reduced by 41%. How has Växjö achieved this impressive result and are there any lessons that could be transferred to Australian cities? This paper describes research which compares Växjö with the Victorian City of Ballarat. The research shows that per capita emissions for Ballarat are 133% higher than those in Växjö. Upgrading the typical Ballarat home to a 6-star rating, and installing a gas-boosted solar water heater and 4.0 kW PV system on the roof could reduce per capita emissions to similar levels to those in Växjö.

  • 126.
    Fuller, Robert
    et al.
    School of Architecture and Built Environment, Deakin University, Geelong,Australia.
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Six million in Melbourne or a network of sustainablemidi-cities? – a thought experiment2013Ingår i: Six million in Melbourne or a network of sustainablemidi-cities? – a thought experiment, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    By 2050, it is projected that Melbourne will have a population of between 5.6 and 6.4 million (DPCD, 2012), an increase of nearly 50% above its current level. Despite Melbourne's status as the world's most liveable city, a recent survey found that Australians in general found smaller cities are better places to live and bring up families (Perkins, 2013). The Grattan Institute's report entitled "The Cities We Need" was "an invitation to a conversation" about our future cities (Kelly, 2010:5). One idea not canvassed in the report was that of decentralization to accommodate Melbourne's projected growth. In its discussion paper, "Let's Talk about the Future", the Victorian State Government proposes that Melbourne become a 'polycentric city' linked to its regional cities (DPCD, 2012). While growth in the present regional cities is acknowledged, the possibility that these and other new regional cities could absorb the future population projected for Melbourne is not considered, nor that these regional cities could be transformed into 'sustainable cities'. This paper explores the idea that a network of smaller 'midi-cities, based on the sustainable city concept of Sweden, might provide a better alternative to concentrated growth in one city. Fifteen new cities of 150,000 would be required to absorb the projected extra 2.3 million Victorian residents. The paper analyses the energy, food, water and land requirements of a typical sustainable city. The new cities would require approximately 12% of the State's land area for food and energy supply, as well as the built environment.             

  • 127.
    Gebremedhin, Alemayehu
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    The role of a paper mill in a merged district heating system2003Ingår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 23, nr 6, s. 769-778Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent studies have shown that there is great potential benefit in utilities collaborating around heat supply. Analyses based on an extended system boundary clarify the advantage of mutual co-operation in the district heating markets. The purpose of this study is to show how far a local paper mill affects the degree of co-operation between two utilities. Current and future electricity prices and existing and potential plants are considered in the different scenarios in the study. The results in all the scenarios clearly show that the paper mill plays an active role in an integrated heat supply system. The scenario where co-operation, new plants and future electricity prices are considered, gives the lowest total system cost. A new back pressure turbine with a higher electricity-to-heat output ratio in combination with high trade prices promotes increased electricity and heat generation in the co-generation plant. The proportion of combined heat and power in district heating would increase if co-operation between the players were encouraged. ⌐ 2003 Elsevier Science Ltd. All rights reserved.

  • 128.
    Gebremedhin, Alemayehu
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Carlson, A.
    Optimisation of merged district - heating systems - Benefits of co - operaion in the light of externality costs2002Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 73, nr 3-4, s. 223-235Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Studies have shown that separate actors can benefit from co-operation around heat supply. Such co-operation, for example, might be between an industry selling waste heat to a districtheating system or two district-heating systems interconnecting their respective systems. Cooperation could also be expected to reduce the environmental impacts of the energy systems by choosing the plants with the lowest emissions. It is widely accepted that the production of heat and electricity causes damage to the environment. This damage often imposes a cost on society, but not on company responsible. In general, using a broader system perspective when analysing local energy systems results in a lower total cost, more e.cient use of plants and a greater potential for producing electricity in combined heat-and-power (CHP) plants. Internalising the externality costs in the energy system model facilitates the study of what cooperation can mean for reducing emissions. This study shows that co-operation between the two systems is on the whole cost-effective, but the benefits are greater when external costs are not included in the calculation. Considering externality costs in combination with current electricity prices would lead to a higher system cost, but the quantity of emission gases will be lower. If, on the other hand, the calculation is made taking externality costs and corresponding adjusted electricity prices (the adjustment being necessary to compensate for the additional cost due to externality costs) into consideration, the quantities of emission gases will rise because more heat-and-power will be generated by one of the CHP plants. © 2002 Elsevier Science Ltd. All rights reserved.

  • 129.
    Gebremedhin, Alemayehu
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Karlsson, Björn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Bjornfot , K
    Shell Raffinaderi AB.
    Sustainable energy system - A case study from Chile2009Ingår i: RENEWABLE ENERGY, ISSN 0960-1481 , Vol. 34, nr 5, s. 1241-1244Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents some of the results of a power system analysis for Chile. The two major Chilean electric systems are roughly modelled and optimized using a linear programming method with the option to integrate renewable energy sources like wind power, solar power, mini-hydropower and biomass-fired power and also "municipal waste". A total of four different scenarios are outlined: reference system, new production units, gas and coal price variations and a policy measure to encourage power production based on renewable energy. The objective of the scenarios was to illustrate under what conditions integration of the different energy sources in the existing production system is possible. The study shows that even under current conditions, mini-hydro and waste to energy plants are economically viable. Wind power might be interesting alternatives if policy instrument measures are applied. On the other hand, it is hard for the other energy sources to enter the system even when higher price levels of gas and coal are applied. The system is more sensitive to coal price increases than to gas price increases and this mainly encourages CO2 emission reduction.

  • 130.
    Ghadimi, M
    et al.
    Department of mechanical engineering, Islamic Azad University, Roudehen Branch, Tehran, Iran.
    Ghadamian, H
    Department of Energy, Materials and Energy Research Center (MERC), Tehran, Iran.
    Hamidi, A A
    School of Chemical Engineering, College of Engineering, University of Tehran, Iran.
    Shakouri, M
    Department of Energy Engineering and Young Researchers and Elites Club, Science and Research Branch, Islamic Azad University, Tehran, Iran.
    Ghahremanian, Shahriar
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. Department of Building, Energy and Environmental Engineering, Faculty of Engineering and Sustainable Development, University of Gävle, Sweden.
    Numerical analysis and parametric study of the thermal behavior in multiple-skin facades2013Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 67, s. 44-55Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The general aim of this research is contributed to the energy performance assessment of single storey multiple-skin facade. To cover this aim; multiple skin facade are studied by means of experiments and numerical simulation. In this research a numerical model for multiple-skin facades with mechanical and natural ventilation has been developed. The numerical model is two-dimensional and based on a cell centered volume method (CVM). As an improvement, radiation and convection are treated separately and by this means an innovative method is applied to calculate the view factors and heat transfer coefficients between surfaces and each cavity. Then the developed numerical model is validated using measurements from the vliet test building. However, there is no multiple-skin facade application in Tehran. Thus the model is used to assess the influence of different multiple-skin facade parameters in Tehrans climate conditions to show its effect on heat losses if this technology would be applied. As a consequence of the diversity of results, designer should be aware that multiple-skin facades do not necessarily improve the energy efficiency of their designs.

  • 131. Beställ onlineKöp publikationen >>
    Ghahremanian, Shahriar
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Near-Field Study of Multiple Interacting Jets: Confluent Jets2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis deals with the near-field of confluent jets, which can be of interest in many engineering applications such as design of a ventilation supply device. The physical effect of interaction between multiple closely spaced jets is studied using experimental and numerical methods. The primary aim of this study is to explore a better understanding of flow and turbulence behavior of multiple interacting jets. The main goal is to gain an insight into the confluence of jets occurring in the near-field of multiple interacting jets.

    The array of multiple interacting jets is studied when they are placed on a flat and a curved surface. To obtain the boundary conditions at the nozzle exits of the confluent jets on a curved surface, the results of numerical prediction of a cylindrical air supply device using two turbulence models (realizable 𝑘 − 𝜖 and Reynolds stress model) are validated with hot-wire anemometry (HWA) near different nozzles discharge in the array. A single round jet is then studied to find the appropriate turbulence models for the prediction of the three-dimensional flow field and to gain an understanding of the effect of the boundary conditions predicted at the nozzle inlet. In comparison with HWA measurements, the turbulence models with low Reynolds correction (𝑘 − 𝜖 and shear stress transport [SST] 𝑘 − 𝜔) give reasonable flow predictions for the single round jet with the prescribed inlet boundary conditions, while the transition models (𝑘 − 𝑘l − 𝜔𝜔 and transition SST 𝑘 − 𝜔) are unable to predict the flow in the turbulent region. The results of numerical prediction (low Reynolds SST 𝑘 − 𝜔 model) using the prescribed inlet boundary conditions agree well with the HWA measurement in the nearfield of confluent jets on a curved surface, except in the merging region.

    Instantaneous velocity measurements are performed by laser Doppler anemometry (LDA) and particle image velocimetry (PIV) in two different configurations, a single row of parallel coplanar jets and an inline array of jets on a flat surface. The results of LDA and PIV are compared, which exhibit good agreement except near the nozzle exits.

    The streamwise velocity profile of the jets in the initial region shows a saddle back shape with attenuated turbulence in the core region and two off-centered narrow peaks. When confluent jets issue from an array of closely spaced nozzles, they may converge, merge, and combine after a certain distance downstream of the nozzle edge. The deflection plays a salient role for the multiple interacting jets (except in the single row configuration), where all the jets are converged towards the center of the array. The jet position, such as central, side and corner jets, significantly influences the development features of the jets, such as velocity decay and lateral displacement. The flow field of confluent jets exhibits asymmetrical distributions of Reynolds stresses around the axis of the jets and highly anisotropic turbulence. The velocity decays slower in the combined regio  of confluent jets than a single jet. Using the response surface methodology, the correlations between characteristic points (merging and combined points) and the statistically significant terms of the three design factors (inlet velocity, spacing between the nozzles and diameter of the nozzles) are determined for the single row of coplanar parallel jets. The computational parametric study of the single row configuration shows that spacing has the greatest impact on the near-field characteristics.

    Delarbeten
    1. A study on proximal region of low Reynolds confluent jets Part I: Evaluation of turbulence models in prediction of inlet boundary conditions
    Öppna denna publikation i ny flik eller fönster >>A study on proximal region of low Reynolds confluent jets Part I: Evaluation of turbulence models in prediction of inlet boundary conditions
    2014 (Engelska)Ingår i: ASHRAE Transactions 2014: ASHRAE Winter Conference, January 18-22, 2014, New York, New York. Pt. 1., New York: ASHRAE , 2014, Vol. 120, nr Part 1, NY-14-021, s. 256-270Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Conventional ventilation systems (mixing and displacement) produce low air quality in industrial premises.A newair supply system (confluent jets system) may improve the ventilation efficiency and the energy efficiency. When round jets issue from co-planar nozzles with enough spacing, they converge, merge, and combine at certain downstream distances, which are called confluent jets. In order to numerically predict confluent jets, it is crucial to provide inlet boundary conditions for these jets at the nozzles’ exit. Numerical prediction of inlet boundary conditions of confluent jets was chosen due to two reasons: the difficulty of measurement at the nozzles’ exit, and lack of information about the shape of the employed nozzles to make artificial inlet profiles. Numerical predictions by two turbulence models (Realizable k –and RSM) of the supply device producing the confluent jets was verified by hot-wire measurements at 0.26 d0 downstream of the nozzles’ exit in both lateral and vertical direction. The verification was carried out for different nozzles in an array by measuring axial velocity and its turbulence intensity. The axial velocity profile at the nozzles exit has a saddle-back shape with two distinct off-centered overshoots. The convergence of the velocity profile shows the existence ofVena contracta phenomena. Low turbulence intensity at the central part of nozzles was found with narrow shear layer upstream of confluent jet flow. Differences of velocity components, turbulent kinetic energy (TKE), and turbulent dissipation rate (TDR) of the studied contraction nozzle were examined with a flow issuing from a typical long pipe. Reynolds number dependency in the studied range has been carried out and Re effects were observed on TKE but not on TDR.

    Ort, förlag, år, upplaga, sidor
    New York: ASHRAE, 2014
    Serie
    ASHRAE Transactions, ISSN 0001-2505
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-109448 (URN)2-s2.0-84902115837 (Scopus ID)978-193650470-1 (ISBN)
    Konferens
    ASHRAE Winter Conference, January 18-22, 2014, New York, New York, USA
    Tillgänglig från: 2014-08-19 Skapad: 2014-08-19 Senast uppdaterad: 2015-04-21Bibliografiskt granskad
    2. Evaluation of RANS Models in Predicting Low Reynolds, Free, Turbulent Round Jet
    Öppna denna publikation i ny flik eller fönster >>Evaluation of RANS Models in Predicting Low Reynolds, Free, Turbulent Round Jet
    2014 (Engelska)Ingår i: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 136, nr 1, s. 011201-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In order to study the flow behavior of multiple jets, numerical prediction of the three-dimensional domain of round jets from the nozzle edge up to the turbulent region is essential. The previous numerical studies on the round jet are limited to either two-dimensional investigation with Reynolds-averaged Navier-Stokes (RANS) models or three-dimensional prediction with higher turbulence models such as large eddy simulation (LES) or direct numerical simulation (DNS). The present study tries to evaluate different RANS turbulence models in the three-dimensional simulation of the whole domain of an isothermal, low Re (Re = 2125, 3461, and 4555), free, turbulent round jet. For this evaluation the simulation results from two two-equation (low Re k - epsilon and low Re shear stress transport (SST) k - omega), a transition three-equation (k - kl - omega), and a transition four-equation (SST) eddy-viscosity turbulence models are compared with hot-wire anemometry measurements. Due to the importance of providing correct inlet boundary conditions, the inlet velocity profile, the turbulent kinetic energy (k), and its specific dissipation rate (omega) at the nozzle exit have been employed from an earlier verified numerical simulation. Two-equation RANS models with low Reynolds correction can predict the whole domain (initial, transition, and fully developed regions) of the round jet with prescribed inlet boundary conditions. The transition models could only reach to a good agreement with the measured mean axial velocities and its rms in the initial region. It worth mentioning that the round jet anomaly is still present in the turbulent region of the round jet predicted by the low Re k - epsilon. By comparing the k and the omega predicted by different turbulence models, the blending functions in the cross-diffusion term is found one of the reasons behind the more consistent prediction by the low Re SST k - omega.

    Ort, förlag, år, upplaga, sidor
    American Society of Mechanical Engineers (ASME), 2014
    Nyckelord
    round jet, low Reynolds, RANS models, SST k-omega, hot-wire anemometry
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-102710 (URN)10.1115/1.4025363 (DOI)000327511000009 ()
    Anmärkning

    Funding Agencies|University of Gavle, Sweden||

    Tillgänglig från: 2013-12-19 Skapad: 2013-12-19 Senast uppdaterad: 2017-12-06Bibliografiskt granskad
    3. Near-field development of a row of round jets at low Reynolds numbers
    Öppna denna publikation i ny flik eller fönster >>Near-field development of a row of round jets at low Reynolds numbers
    2014 (Engelska)Ingår i: Experiments in Fluids, ISSN 0723-4864, E-ISSN 1432-1114, Vol. 55, nr 8, s. 1789-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This article reports on an experimental investigation of the near-field behavior of interacting jets at low Reynolds numbers (Re = 2125, 3290 and 4555). Two measurement techniques, particle image velocimetry (PIV) and laser Doppler anemometry (LDA), were employed to measure mean velocity and turbulence statistics in the near field of a row of six parallel coplanar round jets with equidistant spacing. The overall results from PIV and LDA measurements show good agreement, although LDA enabled more accurate measurements in the thin shear layers very close to the nozzle exit. The evolution of all six coplanar jets showed initial, merging, and combined regions. While the length of the potential core and the maximum velocity in the merging region are Reynolds number-dependent, the location of the merging points and the minimum velocity between jets were found to be independent of Reynolds number. Side jets at the edges of the coplanar row showed a constant decay rate of maximum velocity after their core region, which is comparable to a single round jet. Jets closer to the center of the row showed reducing velocity decay in the merging region, which led to a higher maximum velocity compared to a single round jet. A comparison with the flow for an in-line array of 6 × 6 round jets showed that the inward bending of streamwise velocity, which exists in the near field of the 6 × 6 jet array, does not occur in the single row of coplanar jets, although both setups have identical nozzle shape, spacing, and Reynolds number.

    Ort, förlag, år, upplaga, sidor
    Springer Berlin/Heidelberg, 2014
    Nationell ämneskategori
    Maskinteknik Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:liu:diva-109451 (URN)10.1007/s00348-014-1789-2 (DOI)000340838300014 ()
    Tillgänglig från: 2014-08-19 Skapad: 2014-08-19 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    4. A study on proximal region of low Reynolds confluent jets Part II: Numerical verification of the flow field
    Öppna denna publikation i ny flik eller fönster >>A study on proximal region of low Reynolds confluent jets Part II: Numerical verification of the flow field
    2014 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Conventional ventilation systems (mixing and displacement) produce low air quality in industrial premises.A new air supply system (confluent jet system) may improve both ventilation and energy efficiency. When round jets are issued from coplanar nozzles with enough spacing, they converge, merge, and combine at a certain downstream distance, which are called “confluent jets.” In this study, the velocity field of the proximal region of confluent jets was recorded by traversing a hot-wire probe across the jets in one column at selected distances from the nozzles’ exit in order to examine the performance of SST turbulence model. The experimental and numerical results from this work are summarized in a set of mapping fields of mean velocity for the confluent jet zones, which are presented in a generalized non-dimensional form. The existence of an initial, a converging, a merging, and a combined region in the confluent jets has been found for three low Reynolds numbers. Three different confluent jets can be seen in the array of jets studied placed six by six symmetrically on the long side of a cylindrical supply device. The streamwise velocity of the geometrical centerline of side jets and corner jets decays faster than that for the fully confluent jets, due to deflection towards their adjacent neighboring jets. Side jets and corner jets deflect to their adjacent jets and finally merge and combine with them, while fully confluent jets normally spread and amalgamate with each other. Low local pressure is responsible for the amalgamation of confluent jets, but the static pressure reaches a minimum value between side jets and their neighboring jets, which results in the deflection of the side jets.

    Ort, förlag, år, upplaga, sidor
    New York: ASHRAE, 2014
    Serie
    ASHRAE Transactions, ISSN 0001-2505
    Nationell ämneskategori
    Maskinteknik
    Identifikatorer
    urn:nbn:se:liu:diva-109450 (URN)978-193650470-1 (ISBN)
    Konferens
    2014 ASHRAE Winter Conference; New York, NY; United States; 18 January 2014 through 22 January 2014; Code 10631
    Tillgänglig från: 2014-08-19 Skapad: 2014-08-19 Senast uppdaterad: 2016-05-18Bibliografiskt granskad
    5. Near-field mixing of jets issuing from an array of round nozzles
    Öppna denna publikation i ny flik eller fönster >>Near-field mixing of jets issuing from an array of round nozzles
    2014 (Engelska)Ingår i: International Journal of Heat and Fluid Flow, ISSN 0142-727X, E-ISSN 1879-2278, Vol. 47, s. 84-100Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This article presents results of an experimental study of the confluence of low Reynolds number jets inthe near field of a 6 6 in-line array of round nozzles. Particle Image Velocimetry (PIV) and Laser DopplerAnemometry (LDA) were employed to measure mean velocities and turbulence statistics. The comparisonof the results from PIV and LDA measurements along different cross-sectional profiles and geometricalcenterlines showed good agreement. However, LDA enabled more accurate results very close to the nozzleexits. The evolution of all the individual jets in the array into a single jet showed flow regions similarto twin jets (i.e., initial, converging including mixing transition, merging and combined regions). The lateraldisplacements play an important role for a confluent jet, where all jets to some degree are deflectedtowards the center of the nozzle plate. The jet development in terms of velocity decay, length of potentialcore and lateral displacement varies significantly with the position of the jet in the array. A comparisonwith single jet and twin jets flow showed considerable differences in velocity decay as well as locationand velocity in the combined point. The flow field of confluent jets showed asymmetrical distributionsof Reynolds stresses around the axis of the jets and highly anisotropic turbulence. Additionally, the lateraldisplacement as well as the turbulence development in the proximal region of the studied confluent jetwas shown to be dependent on Reynolds number.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2014
    Nyckelord
    Low Reynolds number round jet, Jet-to-jet interaction, Multiple jet array, Confluent jets, Particle Image Velocimetry (PIV), Laser Doppler Anemometry (LDA)
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:liu:diva-106380 (URN)10.1016/j.ijheatfluidflow.2014.01.007 (DOI)000336773700008 ()
    Forskningsfinansiär
    Vetenskapsrådet, 2008-31145-61023-37
    Tillgänglig från: 2014-05-06 Skapad: 2014-05-06 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    6. Investigation in the near-field of a row of interacting jets
    Öppna denna publikation i ny flik eller fönster >>Investigation in the near-field of a row of interacting jets
    2015 (Engelska)Ingår i: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 137, nr 12Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Multiple interacting jets (confluent jets) are employed in many engineering applications, and the significant design factors must be investigated. Computational fluid dynamics (CFD) is used to numerically predict the flow field in the proximal region of a single row of round jets. The numerical results that are obtained when using the low Reynolds kε are validated with the experimental data that is acquired by particle image velocimetry (PIV). The low Reynolds kε underpredicts the streamwise velocity in the onset of the jets’ decay. The characteristic points are determined for various regions between two neighboring jets. The comparison of the merging point and the combined point computed from measurements and simulations shows good agreement in the different regions between the jets. In this study, a computational parametric study is also conducted to determine the main effects of three design factors and the interactions between them on the flow field development using response surface methodology. The influences of the inlet velocity, the spacing between the nozzles and the diameter of the nozzles on the locations of the characteristic points are presented in the form of correlations (regression equations). CFD is used to numerically predict the characteristic points for a set of required studies, for which the design values of the simulation cases are determined by the Box-Behnken method. The results indicate that the spacing between the nozzles has a major impact on the flow characteristics in the near-field region of multiple interacting jets. The response surface methodology shows that the inlet velocity has a marginal effect on the merging and combined points.

    Nyckelord
    Multiple interacting jets, confluent jets, axisymmetric jet, Low Reynolds number jet, Particle Image Velocimetry (PIV), Low Reynolds k — ε, Response Surface Method
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:liu:diva-113258 (URN)10.1115/1.4031014 (DOI)000364791500010 ()
    Anmärkning

    Funding agencies: University of Gavle, Sweden

    Tillgänglig från: 2015-01-13 Skapad: 2015-01-13 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
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  • 132.
    Ghahremanian, Shahriar
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    A study on proximal region of low Reynolds confluent jets Part I: Evaluation of turbulence models in prediction of inlet boundary conditions2014Ingår i: ASHRAE Transactions 2014: ASHRAE Winter Conference, January 18-22, 2014, New York, New York. Pt. 1., New York: ASHRAE , 2014, Vol. 120, nr Part 1, NY-14-021, s. 256-270Konferensbidrag (Refereegranskat)
    Abstract [en]

    Conventional ventilation systems (mixing and displacement) produce low air quality in industrial premises.A newair supply system (confluent jets system) may improve the ventilation efficiency and the energy efficiency. When round jets issue from co-planar nozzles with enough spacing, they converge, merge, and combine at certain downstream distances, which are called confluent jets. In order to numerically predict confluent jets, it is crucial to provide inlet boundary conditions for these jets at the nozzles’ exit. Numerical prediction of inlet boundary conditions of confluent jets was chosen due to two reasons: the difficulty of measurement at the nozzles’ exit, and lack of information about the shape of the employed nozzles to make artificial inlet profiles. Numerical predictions by two turbulence models (Realizable k –and RSM) of the supply device producing the confluent jets was verified by hot-wire measurements at 0.26 d0 downstream of the nozzles’ exit in both lateral and vertical direction. The verification was carried out for different nozzles in an array by measuring axial velocity and its turbulence intensity. The axial velocity profile at the nozzles exit has a saddle-back shape with two distinct off-centered overshoots. The convergence of the velocity profile shows the existence ofVena contracta phenomena. Low turbulence intensity at the central part of nozzles was found with narrow shear layer upstream of confluent jet flow. Differences of velocity components, turbulent kinetic energy (TKE), and turbulent dissipation rate (TDR) of the studied contraction nozzle were examined with a flow issuing from a typical long pipe. Reynolds number dependency in the studied range has been carried out and Re effects were observed on TKE but not on TDR.

  • 133.
    Ghahremanian, Shahriar
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    A study on proximal region of low Reynolds confluent jets Part II: Numerical verification of the flow field2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Conventional ventilation systems (mixing and displacement) produce low air quality in industrial premises.A new air supply system (confluent jet system) may improve both ventilation and energy efficiency. When round jets are issued from coplanar nozzles with enough spacing, they converge, merge, and combine at a certain downstream distance, which are called “confluent jets.” In this study, the velocity field of the proximal region of confluent jets was recorded by traversing a hot-wire probe across the jets in one column at selected distances from the nozzles’ exit in order to examine the performance of SST turbulence model. The experimental and numerical results from this work are summarized in a set of mapping fields of mean velocity for the confluent jet zones, which are presented in a generalized non-dimensional form. The existence of an initial, a converging, a merging, and a combined region in the confluent jets has been found for three low Reynolds numbers. Three different confluent jets can be seen in the array of jets studied placed six by six symmetrically on the long side of a cylindrical supply device. The streamwise velocity of the geometrical centerline of side jets and corner jets decays faster than that for the fully confluent jets, due to deflection towards their adjacent neighboring jets. Side jets and corner jets deflect to their adjacent jets and finally merge and combine with them, while fully confluent jets normally spread and amalgamate with each other. Low local pressure is responsible for the amalgamation of confluent jets, but the static pressure reaches a minimum value between side jets and their neighboring jets, which results in the deflection of the side jets.

  • 134.
    Ghahremanian, Shahriar
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Evaluation of RANS Models in Predicting Low Reynolds, Free, Turbulent Round Jet2014Ingår i: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 136, nr 1, s. 011201-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to study the flow behavior of multiple jets, numerical prediction of the three-dimensional domain of round jets from the nozzle edge up to the turbulent region is essential. The previous numerical studies on the round jet are limited to either two-dimensional investigation with Reynolds-averaged Navier-Stokes (RANS) models or three-dimensional prediction with higher turbulence models such as large eddy simulation (LES) or direct numerical simulation (DNS). The present study tries to evaluate different RANS turbulence models in the three-dimensional simulation of the whole domain of an isothermal, low Re (Re = 2125, 3461, and 4555), free, turbulent round jet. For this evaluation the simulation results from two two-equation (low Re k - epsilon and low Re shear stress transport (SST) k - omega), a transition three-equation (k - kl - omega), and a transition four-equation (SST) eddy-viscosity turbulence models are compared with hot-wire anemometry measurements. Due to the importance of providing correct inlet boundary conditions, the inlet velocity profile, the turbulent kinetic energy (k), and its specific dissipation rate (omega) at the nozzle exit have been employed from an earlier verified numerical simulation. Two-equation RANS models with low Reynolds correction can predict the whole domain (initial, transition, and fully developed regions) of the round jet with prescribed inlet boundary conditions. The transition models could only reach to a good agreement with the measured mean axial velocities and its rms in the initial region. It worth mentioning that the round jet anomaly is still present in the turbulent region of the round jet predicted by the low Re k - epsilon. By comparing the k and the omega predicted by different turbulence models, the blending functions in the cross-diffusion term is found one of the reasons behind the more consistent prediction by the low Re SST k - omega.

  • 135.
    Ghahremanian, Shahriar
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle, Sweden.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle, Sweden.
    Investigation in the near-field of a row of interacting jets2015Ingår i: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 137, nr 12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multiple interacting jets (confluent jets) are employed in many engineering applications, and the significant design factors must be investigated. Computational fluid dynamics (CFD) is used to numerically predict the flow field in the proximal region of a single row of round jets. The numerical results that are obtained when using the low Reynolds kε are validated with the experimental data that is acquired by particle image velocimetry (PIV). The low Reynolds kε underpredicts the streamwise velocity in the onset of the jets’ decay. The characteristic points are determined for various regions between two neighboring jets. The comparison of the merging point and the combined point computed from measurements and simulations shows good agreement in the different regions between the jets. In this study, a computational parametric study is also conducted to determine the main effects of three design factors and the interactions between them on the flow field development using response surface methodology. The influences of the inlet velocity, the spacing between the nozzles and the diameter of the nozzles on the locations of the characteristic points are presented in the form of correlations (regression equations). CFD is used to numerically predict the characteristic points for a set of required studies, for which the design values of the simulation cases are determined by the Box-Behnken method. The results indicate that the spacing between the nozzles has a major impact on the flow characteristics in the near-field region of multiple interacting jets. The response surface methodology shows that the inlet velocity has a marginal effect on the merging and combined points.

  • 136.
    Ghahremanian, Shahriar
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle, Sweden.
    Svensson, Klas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Tummers, Mark J.
    Delft University of Technology, The Netherlands.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle, Sweden.
    Near-field development of a row of round jets at low Reynolds numbers2014Ingår i: Experiments in Fluids, ISSN 0723-4864, E-ISSN 1432-1114, Vol. 55, nr 8, s. 1789-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article reports on an experimental investigation of the near-field behavior of interacting jets at low Reynolds numbers (Re = 2125, 3290 and 4555). Two measurement techniques, particle image velocimetry (PIV) and laser Doppler anemometry (LDA), were employed to measure mean velocity and turbulence statistics in the near field of a row of six parallel coplanar round jets with equidistant spacing. The overall results from PIV and LDA measurements show good agreement, although LDA enabled more accurate measurements in the thin shear layers very close to the nozzle exit. The evolution of all six coplanar jets showed initial, merging, and combined regions. While the length of the potential core and the maximum velocity in the merging region are Reynolds number-dependent, the location of the merging points and the minimum velocity between jets were found to be independent of Reynolds number. Side jets at the edges of the coplanar row showed a constant decay rate of maximum velocity after their core region, which is comparable to a single round jet. Jets closer to the center of the row showed reducing velocity decay in the merging region, which led to a higher maximum velocity compared to a single round jet. A comparison with the flow for an in-line array of 6 × 6 round jets showed that the inward bending of streamwise velocity, which exists in the near field of the 6 × 6 jet array, does not occur in the single row of coplanar jets, although both setups have identical nozzle shape, spacing, and Reynolds number.

  • 137.
    Ghahremanian, Shahriar
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle, Sweden.
    Svensson, Klas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Tummers, Mark J.
    Delft University of Technology, The Netherlands.
    Moshfegh, Bahram
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan. University of Gävle, Sweden.
    Near-field mixing of jets issuing from an array of round nozzles2014Ingår i: International Journal of Heat and Fluid Flow, ISSN 0142-727X, E-ISSN 1879-2278, Vol. 47, s. 84-100Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents results of an experimental study of the confluence of low Reynolds number jets inthe near field of a 6 6 in-line array of round nozzles. Particle Image Velocimetry (PIV) and Laser DopplerAnemometry (LDA) were employed to measure mean velocities and turbulence statistics. The comparisonof the results from PIV and LDA measurements along different cross-sectional profiles and geometricalcenterlines showed good agreement. However, LDA enabled more accurate results very close to the nozzleexits. The evolution of all the individual jets in the array into a single jet showed flow regions similarto twin jets (i.e., initial, converging including mixing transition, merging and combined regions). The lateraldisplacements play an important role for a confluent jet, where all jets to some degree are deflectedtowards the center of the nozzle plate. The jet development in terms of velocity decay, length of potentialcore and lateral displacement varies significantly with the position of the jet in the array. A comparisonwith single jet and twin jets flow showed considerable differences in velocity decay as well as locationand velocity in the combined point. The flow field of confluent jets showed asymmetrical distributionsof Reynolds stresses around the axis of the jets and highly anisotropic turbulence. Additionally, the lateraldisplacement as well as the turbulence development in the proximal region of the studied confluent jetwas shown to be dependent on Reynolds number.

  • 138.
    Gong, Mei
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Optimization of industrial energy systems by incorporating feedback loops into the MIND method2003Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 28, nr 15, s. 1655-1669Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The MIND (Method for analysis of INDustrial energy system) method has been developed for multi-period cost optimization of industrial energy systems. Existing industrial processes can be represented at the desired level of accuracy, i.e. one modeling unit may represent a part of the production process or the whole plant. The optimization method includes both energy and material flows. Nonlinear relations, energy conversion efficiencies and investment costs are linearized by mixed-integer linear programming. A flexible time-scale facilitates the performance of long- and short-term analyses. In order to meet the requirements with regard to sustainable development, the recycling of energy and material flows is becoming more common in many industrial processes. The recycling or reuse of energy and material is managed by feedback loops, which are incorporated into the original MIND method to improve the model and reduce the calculation time. The improved MIND/F method (MIND method with feedback loops) model is applied to a pulp and paper mill in Sweden. A comparison between the original MIND method with manual handling of the feedback loops and the MIND/F method gives highly satisfactory results. Cost optimization using the improved MIND method is well within the given accuracy and computer time and manual calculation time are both reduced considerably. The reuse of energy and material resources is not only an economic advantage, but also implies a reduction of the environmental impact.

  • 139.
    Gong, Mei
    et al.
    Linköpings universitet, Institutionen för konstruktions- och produktionsteknik, Energisystem. Linköpings universitet, Tekniska högskolan.
    Karlsson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Söderström, Mats
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Industry and the energy market - optimal choice of measures using the MIND method2002Ingår i: CRIS Conference on Power Systems and Communications Infrastructures for the future, 2002, China: CRIS, International Institute for Critical Infrastructures , 2002Konferensbidrag (Refereegranskat)
    Abstract [en]

    No abstract available.

  • 140.
    Govik, Alexander
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Nilsson, Larsgunnar
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
    Moshfegh, Ramin
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Stochastic analysis of a sheet metal assembly considering its manufacturing process2014Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    In order to accurately predict the mechanical properties of a sheet metal assembly it has been shown important to account for how the geometry and material properties are affected by the manufacturing process. It is also of a great interest to predict the variations of important responses, and how these variations depend on the manufacturing process.

    In this study, the variation of properties during the multi-stage manufacturing process of a sheet metal assembly is evaluated and the variability of a response due to loading is studied. A methodology to investigate how variations evolve during the assembling process is presented. The multi-stage assembling process is virtually segmented, such that stochastic analyses of each process stage are performed and coupled to succeeding stages in order to predict the variation in properties of the final assembly. The methodology is applied to an industrial assembly and experimental validations have been conducted. The prediction of the geometry of the final assembly is in good agreement with the experimental results, while the prediction of the variation of this geometry is in fair agreement.

  • 141.
    Grip, Carl-Erik
    et al.
    Luleå University of Technology.
    Dahl, Jan
    Luleå University of Technology.
    Söderström, Mats
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Exergy as a means for process integration in integrated steel plants and process industries2009Ingår i: STAHL UND EISEN, ISSN 0340-4803, Vol. 129, nr 9, s. S2-S8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Exergy analysis can be a useful tool for process comparison and improvement in industrial energy systems. Examples from three branches are given: pulp and paper, bio refineries (ethanol) and steel production. The application and development of exergy analysis in an integrated steel plant is shown together with description and explanations on destroyed and lost exergy. Implementation for energy conservation and use as a pedagogic tool is discussed.

  • 142.
    Grip, Carl-Erik
    et al.
    Luleå University of Technology, Division Energy Technology, Luleå.
    Elfgren, Erik
    Luleå University of Technology, Division Energy Technology, Luleå.
    Söderström, Mats
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Thollander, Patrik
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Berntsson, Thore
    Chalmers University of Technology, Division Heat and Power Technology, Gothenburg.
    Åsblad, Anders
    CIT Industriell Energi, Gothenburg, Sweden.
    Wang, Chuan
    Swerea MEFOS, Luleå .
    Possibilities and problems in using exergy expressions in process integration2011Ingår i: Proceedings of the World Renewable Energy Congress 2011 (WREC 2011), 9-13 May, Linköping., Linköping University Electronic Press, 2011, Vol. 7, s. 1605-1612Konferensbidrag (Refereegranskat)
    Abstract [en]

    Industrial energy systems are complicated networks, where changes in one process influence its neighboring processes. Saving energy in one unit does not necessarily lead to energy savings for the total system. A study has been carried out on the possibility to use the exergy concept in the analysis of industrial energy systems. The exergy concept defines the quality of an amount of energy in relation to its surrounding, expressing the part that could be converted into work. The study consists of literature studies and general evaluations, an extensive case study and an interview study. In the latter it was found that non technical factors are major obstacles to the introduction of exergy.

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    FULLTEXT01
  • 143.
    Gronkvist, Stefan
    et al.
    Royal Institute of Technology, Department of Chemical Engineering and Technology, Division of Energy Processes, Stockholm, Sweden.
    Sjödin, Jörgen
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Westermark, M.
    Royal Institute of Technology, Department of Chemical Engineering and Technology, Division of Energy Processes, Stockholm, Sweden.
    Models for assessing net CO2 emissions applied on district heating technologies2003Ingår i: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 27, nr 6, s. 601-613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Methodologies to assess the effects of energy projects on global carbon dioxide emissions will be an important feature of a future international carbon dioxide trading system. In this paper, we present and discuss four different models for assessing the net carbon dioxide emissions resulting from a certain energy project. These models are applied to different district heating technologies. To judge the mitigation performance of a project, the amount of carbon dioxide released in kilograms is expressed per megawatt-hour of useful district heating produced. All the models consider the marginal change caused by the project on the electric power system. The different model perspectives are discussed, and it is shown that the choice of model is very critical for assessing the net carbon dioxide emissions from an energy project.

  • 144.
    Gröndal, Andreas
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem.
    Gillsäter, Ambjörn
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling.
    Elenergibesparing i pumpsystem2010Självständigt arbete på grundnivå (högskoleexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Med stigande elpriser har det blivit allt viktigare att effektivisera processer som använder sig av elektricitet. Ett område inom pappers- och massaindustrin med stora möjligheter till besparing av elenergi är pumpning. I ett tidigare projekt genomfört av värmeforsk har ett Excelbaserat program för att analysera hela system av pumpar och förbrukare tagits fram. Programmet heter PumpAnalys och med hjälp av detta skall onödigt höga tryck och onödiga strypningar i system gå att visualisera på ett enkelt sätt. Systemet som analyserat är det såkallade sekundärvärmesystemet vid Iggesunds Bruk, vilket har till uppgift att tillvarata värme från terpentin- och tunnlutsflöden.

     

    Den största besparingspotentialen har inte bestått i resultat från PumpAnalys utan i de låga verkningsgraderna (28-65%) hos de pumpar som ingår i systemet. Diagrammet i figur 1 visar energiåtgången i systemet i nuläget samt efter de tre olika effektiviseringsförslagen som tagits fram. Mellan nuläget och förslag 1 har enbart nya pumpar med bättre verkningsgrader föreslagits medan det i förslag 2 och 3 finns med trycksänkning hos startpumpen samt montering av fler pumpar.

     

    Skillnaden i besparing mellan förslag 1 och 2 är marginell trots att en extra tryckförstärkarpump monterats. I förslag 3 ger två extra tryckförstärkarpumpar upphov till ytterligare besparing. Om Effektiviseringsförslag 3 genomförs blir besparingen 612 MWh/år, vilket motsvarar ca 50 % av nuvarande energianvändning i systemet. Denna besparing motsvarar ca 305 000 kr/år. Dock står tryckförändringen endast för ca 131 MWh/år (ca 20 %) av besparingen medan förbättrade verkningsgrader hos pumparna står för resterande besparing. På grund av den extra kostnad som inköp av ytterligare två tryckförstärkarpumpar i förslag 3 åstadkommer är det främst på förslag 1 som fokus för genomförande bör vara.

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    Elenergibesparing i pumpsystem
  • 145.
    Grönkvist, Stefan
    et al.
    Department of Chemical Engineering and Technology, Division of Energy Processes, Royal Institute of Technology, Stockholm, Sweden.
    Sandberg, Peter
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Driving forces and obstacles with regard to co-operation between municipal energy companies and process industries in Sweden2006Ingår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 34, nr 13, s. 1508-1519Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    District heating networks can technically enable energy-related co-operations between energy-intensive industries and municipal energy companies. The most common form of co-operation is to utilise industrial waste heat as the primary energy source in district heating networks. However, another type of co-operation is to jointly own a plant that produces both process steam for the industry and hot water for district heating. In this article, eight Swedish energy co-operations are studied and the main focus is on the process leading to co-operations of this kind. Different aspects of factors that facilitate or obstruct the start up and continuous daily operation of a co-operation are discussed. The main conclusion is that while the primary reasons for the foundation of such co-operations are favourable techno-economic factors, this is not enough for a co-operation to emerge. This study highlights the importance of people with a real ambition to co-operate in both parties in the co-operations.

  • 146.
    Gustafsson (fd Emilsson), Sara
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska högskolan.
    Ivner, Jenny
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska högskolan.
    Palm, Jenny
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Management and stakeholder participation in local strategic energy planning – Examples from Sweden2015Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 98, s. 205-212Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When it comes to improving energy efficiency and environmental sustainability, municipalities are important actors. The Swedish Energy Agency initiated a program called Sustainable Municipalities to support strategic energy activities at the local level. Participating municipalities were mandated to develop local energy and climate strategies. This study gives a general overview of how the 60 participants in the Sustainable Municipalities program developed and used energy strategies. The paper focuses on analyses of whether energy plans or strategies are present, and if present, how the municipalities address the issues, what actors are involved, and whether follow-up of the strategies is pursued. The empirical data were collected using structured telephone interviews and other studies. The paper elucidates local energy strategies from a management perspective, discuss whether and how the composition of actors influences suggested goals and measures, and explore whether there were plans for implementation and follow-ups. The theoretical ambitions are to integrate theories on how to manage efficient strategic energy planning with theories on how to achieve successful participation of stakeholders. These theories are used to discuss weaknesses and strengths in existing municipal energy planning practices and potential improvements.

    The results from this paper show that only 75% of the municipalities adopted local energy strategies. In addition, it was revealed that the processes to develop the strategies generally included several municipal actors although other stakeholders were rarely represented. The strategies resulted in concrete measures; however, there were no clear correlations between included actors, suggested measures, and identified themes in the strategies. The rather limited participation in the process could affect the impact and legitimacy of the strategies.

  • 147.
    Gustafsson, Marcus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Cruz, Igor
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Biogas Research Center.
    Svensson, Niclas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Karlsson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Scenarios for upgrading and distribution of compressed and liquefied biogas: Energy, environmental, and economic analysis2020Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 256, artikel-id 120473Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the transition towards fossil-free transports, there is an increasing interest in upgraded biogas, or biomethane, as a vehicle fuel. Liquefied biogas has more than twice as high energy density as compressed biogas, which opens up the opportunity for use in heavy transports and shipping and for more efficient distribution. There are several ways to produce and distribute compressed and liquefied biogas, but very few studies comparing them and providing an overview. This paper investigates the energy balance, environmental impact and economic aspects of different technologies for upgrading, liquefaction and distribution of biogas for use as a vehicle fuel. Furthermore, liquefaction is studied as a method for efficient long-distance distribution.

    The results show that the differences between existing technologies for upgrading and liquefaction are small in a well-to-tank perspective, especially if the gas is transported over a long distance before use. Regarding distribution, liquefaction can pay back economically after 25–250 km compared to steel container trailers with compressed gas, and reduce the climate change impact after 10–30 km. Distribution in gas grid is better in all aspects, given that it is available and no addition of propane is required. Liquefaction can potentially expand the geographical boundaries of the market for biogas as a vehicle fuel, and cost reductions resulting from technology maturity allow cost-effective liquefaction even at small production capacities.

    Publikationen är tillgänglig i fulltext från 2022-02-08 07:49
  • 148.
    Gustafsson, Marcus
    et al.
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Cruz, Igor
    Linköpings universitet, Biogas Research Center. Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Svensson, Niclas
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Industriell miljöteknik. Linköpings universitet, Tekniska fakulteten.
    Karlsson, Magnus
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Technologies for production of liquefied biogas for heavy transports: Energy, environmental, and economic analysis2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    The heavy transport sector is facing a growth within technology and infrastructure for use of natural gas. This opens an opportunity for the biogas market to grow as well, especially in the form of liquefied biogas (LBG). This study presents an investigation of the energy balance, environmental impact and economic aspects of current technologies for production of LBG: mixed refrigerant cycle, nitrogen cycle, pressure reduction and cryogenic liquefaction. Calculations are based on a review of recent literature and data from the biogas industry. The results show that mixed refrigerant cycle is the most economic and energy efficient technology for liquefaction of upgraded biogas, followed by nitrogen cycle. The lowest electricity use and environmental impact is achieved if the liquefaction process is preceded by amine scrubber upgrading. Pressure reduction liquefaction is inexpensive and can be an alternative in areas connected to a high-pressure gas grid, but as a method for liquefaction it is not very efficient as only about 10% of the incoming gas is liquefied and the rest remains in its gaseous form. Moreover, addition of propane for distribution in the natural gas grid increases the environmental impact compared to other distribution pathways. The cryogenic technology has a higher energy use than other liquefaction technologies but compensates by also including CO₂ separation, which could make it suitable if there is no existing upgrading facility in place. However, there are technical difficulties to overcome and it is not widely implemented.

  • 149.
    Gustafsson, Mattias
    et al.
    Gavle Energi AB, Sweden; University of Gavle, Sweden.
    Ronnelid, Mats
    Dalarna University, Sweden.
    Trygg, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    Karlsson, Bjorn
    University of Gavle, Sweden.
    CO2 emission evaluation of energy conserving measures in buildings connected to a district heating system - Case study of a multi-dwelling building in Sweden2016Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 111, s. 341-350Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When taking action to fulfill the directives from the European Union, energy conserving measures will be implemented in the building sector. If buildings are connected to district heating systems, a reduced heat demand will influence the electricity production if the reduced heat demand is covered by combined heat and power plants. This study analyze five different energy conserving measures in a multi-dwelling building regarding how they affect the marginal production units in the district heating system in Gavle, Sweden. For CO2 emission evaluations, two different combinations of heat and electricity conserving measures are compared to an installation of an exhaust air heat pump. The different energy conserving measures affect the district heating system in different ways. The results show that installing an exhaust air heat pump affects the use/production of electricity in the district heating system most and electricity conserving measures result in reduced use of electricity in the building, reduced use of electricity for production of heat in the district heating system and an increase of electricity production. The conclusion is that electricity use in the building is the most important factor to consider when energy conserving measures are introduced in buildings within the district heating system in Gavle. (C) 2016 Elsevier Ltd. All rights reserved.

  • 150.
    Gustafsson, Mattias
    et al.
    University of Gävle, Sweden.
    Thygesen, Richard
    University of Gävle, Sweden.
    Karlsson, Bjorn
    University of Gävle, Sweden.
    Ödlund, Louise
    Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Energisystem. Linköpings universitet, Tekniska fakulteten.
    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 Buildings2017Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, nr 7, artikel-id 978Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the European Unions 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.

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