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  • 151.
    Mugisha, Jean Claude
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    A study on Auxiliary Battery Energy Storage to Mitigate PV Output Power Fluctuations: Case Study: 8.5 MW Agahozo Shalom Youth Village (ASYV) PV Power Plant in Rwanda2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Solar energy is experiencing a rapid growth worldwide and it is a promising technology to play a vital role in future power systems. However, the natural intermittent of solar energy resources affect the quality of the output power from a solar system putting its dispatchability in question. Battery Energy Storage System (BESS) is among the solutions to suppress PV power fluctuations and allow smooth PV power production as result. In this work, BESS was modelled, integrated and simulated for Agahozo Shalom Youth Village (ASYV) PV Power Plant located in Rwanda. MATLAB/Simulink was used as modelling and simulation tool and Excel was used in data analysis. For ease of work, one of eight PV arrays at the power plant was considered and the results were scaled up to the entire power plant afterwards.

    Annual data for year 2017 was analysed and the worst-case scenario which is the day with highest irradiance variation was found. Both PV power and ambient temperature data for this day were used as input to the model. Four smoothing approaches namely Low Pass Filter (LPF), Simple Moving Average (SMA), Exponential Moving Average (EMA) and Ramp Rate Control (RRC) were investigated in detail, applied to the model and compared in terms of performance and battery size that each approach would require. The degree to which power output needs to be smoothed can vary based on regulatory requirements and the technical conditions of the power grid. For this reason, three Ramp Rate Limits (RRLs) namely ±10 %, ±20 % and ±30 % of the rated PV array power per minute were applied in smoothing algorithms to see how large the battery storage would be if Rwandan grid operator was to impose one of the aforesaid RRLs.

    The results showed that all smoothing methods managed to smoothen out PV array power at all RRLs as intended. The difference occurred in performance of smoothing methods and battery size in terms of power and energy that each method required. In all cases, it was noticed that both LPF and EMA displayed almost similar results which made it difficult to make a clear distinction between the two. However, in their slight difference, EMA required a slightly smaller battery size. The memory effect of SMA was noticed and this method was requiring bigger battery size at all RRLs. The RRC performance was better especially at ±10 % RRL compared to other three methods. The particularity of RRC was that it only allows the battery to respond when needed and the battery charges or discharges the exact amount of power needed. This was different from the other three smoothing methods. They were always allowing the battery to respond even when the present power ramp is within the set RRL resulting in high charging/discharging cycles which causes cyclic degradation of the battery. In addition, these methods over-smoothed the PV array power where more than needed power could be absorbed or delivered by the battery resulting in unnecessary bigger battery size.

    Some of downsides of RRC method were that it requires bigger battery size in terms of energy and it could be more sensitive to the uncertainty associated with PV array power measurement compared to other methods. Nonetheless, its battery size in terms of power requirement was less than other methods since it does not over-smooth the PV array power. Since RRC and EMA methods were requiring less battery power and less battery energy at all RRLs respectively, both methods were chosen while scaling up the results to the entire power plant. Using EMA smoothing methods over RRC at ±10 % RRL could results in saving $113 thousand of battery capital cost. However, at ±20 % and ±30 % RRL, the RRC method was found to be the best option since it needs less capital cost than EMA smoothing approach.

  • 152.
    Muthalagappan, Narayanan
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Correlation of PID with other Reliability Tests for CIGS Solar Cells2014Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    With solar photovoltaic plants getting larger and larger, the balance in the system is getting important. Balance of the system is necessary to get the maximum power from the system by arranging its components in an optimal way. With PV systems having high DC voltages of up to 600V in USA and 1000V in Europe, the high voltage stress induced in the system is a lot. One of the effects created due to an imbalance in the system is the Potential Induced Degradation. Previous researchers have found out that the Potential Induced Degradation (PID) is due to the voltage imbalance in the string (a schematic arrangement of solar modules in a system) which is influenced by the environmental factors. The objective of the project is to characterize the electrical properties of different available CIGS solar cell types and to correlate other reliabilty tests with PID test to find out if PID has any correlation with the other degradation mechanisms. Thus 8 samples were requested from two different manufacturers of different CIGS solar cells which were tested and results were compared and analysed. Therefore it was found out some compostional structure prove stable against the PID. But changing the combinaton of the compounds have a difference. Some relational pattern of degradation with the Stability test was evident. Few of the previous finding were again confirmed with a new path of approach for the further researches.

  • 153.
    Myhren, Jonn Are
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Heier, Johan
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Hugosson, Mårten
    Högskolan Dalarna, Akademin Industri och samhälle, Företagsekonomi.
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    The perception of Swedish housing owner’s on the strategies to increase the rate of energy efficient refurbishment of multi-family buildings2018Inngår i: Intelligent Buildings International, ISSN 1750-8975, E-ISSN 1756-6932Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Improving the energy performance of existing buildings is crucial for reaching both EU and national climate and energy targets. The main objective of this study was to map challenges that Swedish housing owners perceive when making energy-efficiency refurbishments. A secondary objective was to compare how well these challenges relate to national strategies. The study applied a combined methods approach with audience response meters and in-depth qualitative semi-structured interviews. The housing owners express the view that they have sufficient knowledge of national ambitions to improve the energy performance of buildings and welcome the new building regulations. Despite this supposed knowledge and the current economic situation with beneficial loans, the refurbishment rate still remains low. The housing owners explain that they are concerned about the ‘performance gap’ and request more accurate energy performance predictions. They are also waiting for proof that all sustainability goals can be reached in reality. Probably, too few projects fulfilling ambitions in all categories: economically, socially and energy-wise have been followed up and demonstrated nationally. The new national information centre on refurbishment of buildings may help to spread information about such projects, raise awareness and thus increase the refurbishment rate.

    Fulltekst (pdf)
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  • 154.
    Myhren, Jonn Are
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Olofsson, Thomas
    Högskolan Dalarna, Akademin Industri och samhälle, Byggteknik.
    Bergdahl, Martin
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lågtemperaturuppvärmning med tilluftsradiatorer och värmeåtervinning i frånluft: en varsam renovering av flerbostadshus för energieffektivisering2014Rapport (Annet vitenskapelig)
    Abstract [sv]

    För att nå reella sänkningar av energianvändningen i hela byggnadsbeståndet krävs tillgång till kostnadseffektiva renoveringspaket med energieffektiva systemlösningar där samspel mellan installationssystem och byggnad beaktas.

    Denna förstudie belyser möjligheter med alternativa renoveringspaket med lågtemperatur-tilluftsradiatorer och värmeåtervinning i frånluften (FX). Systemkombinationer och jämförelser har gjorts med mera etablerade lösningar med traditionella radiatorer, balanserad mekanisk ventilation (FTX) och solvärme. Mindre prövade lösningar såsom frånluftsmoduler (VBX) kopplat till befintliga värmepumpar och behovsstyrd ventilation undersöktes också.

    Energianvändning och kostnadseffektivitet med de undersökta åtgärdspaketen prövades för två äldre bostadshus med vardera specifika restriktioner: den ena inom fjärrvärmenätet och det andra ett K-märkt hus utanför fjärrvärmenätet. Samtidigt reflekterades det över vilka tekniska lösningar som samtidigt är gynnsammast ur hållbarhetssynpunkt. För flertalet befintliga byggnader behöver såväl metoder som komponenter utvecklas på ett varsamt sätt som uppfyller båda ägarens krav som övergripande mål baserat på systemförutsättning och kostnadseffektivitet.

    Förstudien visar att:

     lågtemperatur-tilluftsradiatorer är en systemkomponent som möjliggör ökad komfort via förvärmning och filtrering av inkommande ventilationsluft, effektivare värmeproduktion och minskning av värmeförluster i distribution av varmvatten. Renovering med installation av FX-system i kombination med lågtemperatur-tilluftradiatorer är ett alternativ till FTX system som begränsar byggåtgärderna i byggnaden och ger lägre livscykelkostnad

     Byggnadsskalets täthet blir avgörande för energinyttan båda med FX- och FTX-system. Förstudien visar att FX-system är fördelaktig i byggnader med dålig lufttäthet

     I byggnader med befintligt frånluftssystem kan behovsstyrning av ventilationen vara ett enkelt och kostnadseffektivt sätt att sänka ventilationsförlusterna och spara energi som alternativ till att installera återvinningssystem

    Förstudien visar klart att energieffektiv renovering kan åstadkommas med val av varsamma metoder som också åstadkommer ökad komfort och systemnytta, utanför såväl som inom fjärrvärmenätet. Samtidigt kan ägarens krav på kostandsnytta nås och byggnaders bevarandekrav uppfyllas.

    Nu krävs det demonstrationsprojekt för att inte minst sprida kunskap i branschen men också applicering på större bostadsområden.

    Fulltekst (pdf)
    fulltext
  • 155.
    Möttönen, Karin
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Hedén, Mikael
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Human Centric Lighting: Automatisk belysningsvariation för hälsa, välbefinnande och elsparande2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Examensarbetet är en undersökning avseende implementering av Human Centric Lighting (HCL)- system i hemmamiljö. En litteraturstudie har genomförts om HCL, dess effekter på människan och LED-belysningens påverkan både på människan och miljön. För att få en bra praktisk grund gjordes även ett undersökande besök på Lindeborgsskolan i Malmö som i ett pilotprojekt har installerat HCL-system i ett klassrum.

    HCL handlar bland annat om att anpassa ljuset till människans varierande behov genom att variera intensitet (Lux) och färgtemperatur (Kelvin). Belysning har stor betydelse för människans välmående där en belysning med onaturlig spektralfördelning och flimmer kan leda till stress, sömnproblem samt att ögonen kan försämras. Ett bra varierande ljus kan däremot öka människans välmående, produktivitet och även ge en positivare inställning. En del forskning visar även på att HCL kan minska risken för årstidsbunden depression. Ett blått, mer intensivt ljus har en uppiggande effekt medan ett rött nerdämpat ljus verkar lugnande. Genom att utsätta kroppen för mycket blått ljus på förmiddagen men inte på eftermiddagen/kvällen gynnas kroppens cirkadiska cykel. Även rött ljus har visat sig ha en uppiggande effekt men påverkar inte den cirkadiska cykeln och kan med fördel användas även på kvällstid om en högre ljusintensitet behövs.

    Tre separata reglerbara belysningssystem har undersökts: Clas Ohlson WiFi Smart Bulb, IKEA trådfri belysning och Philips Hue White Ambiance. Kravet som ställdes för att belysningen skulle tas med i testet var att den skulle finnas tillgänglig i en relativt vanlig butik. Belysningen har testats både med avseende på ljusegenskaper samt energianvändning. En del av mätningarna utfördes med ett Ulbrichtklot på Clas Ohlsons ljuslaboratorium där färgspektrum, lumenvärde samt mycket annan information om ljuskällan kunde tas fram, samt med en handhållen spektrometer för att se flimmeravgivningen ifrån lampan vid olika inställningar. Energianvändningen undersöktes beträffande förändringar vid variation av färgtemperatur, intensitet och även i de fall som separat reglerutrustning krävdes.

    De tre belysningssystemen visade sig ha olika fördelar och nackdelar där en till slut valdes ut för att installeras i ett sovrum i utbildningsprojektet Dalarnas Villa. Baserat på ett tidigare gjort ljusschema, i en masteruppsats gjord av en ljusdesigner vid KTH, togs ett nytt ljusschema fram för sovrummet som förändrar ljusets intensitet och färgtemperatur för att främja den cirkadiska cykeln. Då författarna ser att detta är ett viktigt ämne så har varje möjlighet till att visa upp det installerade systemet tagits. Vid samtal med bland annat energirådgivare från Dalarna så har ett stort intresse visats.

    ” Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity (WHO 1946). Health should be at the centre of all societal planning because social inequalities in health are costly to the society and counteract sustainable development (Malmö stad 2013). It is one of the main conditions for individual development opportunities through education, work, social relationships and participation in the society (UN 1949). Health is a key to the other human rights and also constitutes a separate right (WHO 2008).”

    Sustainability issues for SSL (R. Karlsson et al. 2016)

    Fulltekst (pdf)
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  • 156.
    Nielsen, Caroline
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Travel Report from the first field trip within the SIDA supported project "Mini-grids supplied by renewable energy - improving technical and social feasibility: Including visits to Ihushi Development Center, Tweyambe Secondary School and Mavuno Project in Tanzania. Conducted in April 20112011Rapport (Annet vitenskapelig)
    Abstract [en]

    This report describes the outcome of the first visit to Tanzania, within the project "Mini-grids supplied by renewable energy - improving technical and social feasibility". The trip included visits to three different organizations; Ihushi Development Center (IDC) near Mwanza, TIDESO near Bukoba, and Mavuno Project in Karagwe. At IDC, a brief evaluation of the current power system was done and measuring equipment for long term measurements were installed. At all three locations investigations regarding the current and future electricity demand were conducted and connections to people relevant to the study were established. The report is including as well some technical specifications as some observations regarding organization and management of the technical systems. The trip was including only short visits and therefore only brief introductions to the different organizations, based on observations done by the author. The report is hence describing the author’s understanding of the technical system and social structures after only short visits to each of the organizations, and may differ from observations done at another point in time, over a different time period, or by some other person.This report describes the outcome of the first visit to Tanzania, within the project "Mini-grids supplied by renewable energy - improving technical and social feasibility". The trip included visits to three different organizations; Ihushi Development Center (IDC) near Mwanza, TIDESO near Bukoba, and Mavuno Project in Karagwe. At IDC, a brief evaluation of the current power system was done and measuring equipment for long term measurements were installed. At all three locations investigations regarding the current and future electricity demand were conducted and connections to people relevant to the study were established. The report is including as well some technical specifications as some observations regarding organization and management of the technical systems. The trip was including only short visits and therefore only brief introductions to the different organizations, based on observations done by the author. The report is hence describing the author’s understanding of the technical system and social structures after only short visits to each of the organizations, and may differ from observations done at another point in time, over a different time period, or by some other person.

  • 157.
    Nielsen, Caroline
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Fiedler, Frank
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Evaluation of a Micro PV-Diesel Hybrid System in Tanzania2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In April 2011 a monitoring system was installed to enable studies of the performance and the usage of a micro PV-Diesel Hybrid system at the Ihushi Development Center (IDC) near Mwanza in Tanzania. Estimations of the load have been obtained by a survey of installed appliances and interviews with users of installed equipment. The load profile obtained by measurements has been analyzed and compared to estimations of the energy use. Further, the system size and performance were studied.

    Fulltekst (pdf)
    fulltext
  • 158.
    Nielsen, Christian
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik. Chalmers University.
    Haegermark, Maria
    Dalenbäck, Jan-Olof
    Analysis of a Novel Solar District Heating System2014Inngår i: ISES Conference Proceedings EuroSun 2014, International Solar Energy Society (ISES) , 2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This paper describes a new residential building area with a solar assisted block heating plant. The building area currently comprises 26 single family buildings, four small multifamily buildings, 6 terrace houses and a nursing home for elderly people with 64 apartments. All buildings are designed for a low heat demand    (<45 kWh a-1 m-2) and the total heated floor area is 14 000 m2.  The block heating system comprises a central 250 kW wood pellet boiler, about 700 m2 of distributed roof-integrated solar collectors and a novel heat distribution system. An initial evaluation indicates that designed heat demands, as well as the overall system performance including expected solar contribution, is likely to be met.  Reported measurements include annual (April 2013 – March 2014) heat balances for two substations with single family buildings, yearly solar energy gains (August 2013 – July 2014), and a monthly (March 2014) heat balance for the whole system.

  • 159.
    Niklasson, Fredrik
    et al.
    SP Energiteknik, Borås.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Marknadspotential för bio- och solvärmesystem2008Rapport (Annet vitenskapelig)
    Abstract [sv]

    I denna rapport analyseras marknaden för kombinerade sol- och pelletsystem, medfokus på småhus. Syftet är att presentera antalet objekt inom olika kategorier av husoch värmesystem som kan vara intressanta för konvertering till bio-sol system samtatt ge en uppskattning av årliga uppvärmningsbehov inom respektive kategori.

    Energistatistik från Statistiska centralbyrån (SCB) har använts i kombination medtidigare studier av byggnadsbestånd och byggnadsutformning. Dessutom harinformation inhämtats från olika branschorganisationer.

    Från föreliggande genomgång står det klart att den största potentialen för bio-solsystem finns på villamarknaden både för helt nya system och för kompletteringar tillbefintliga system. År 2006 fanns det 775 000 småhus med vattenburen värme varav ca183 000 hade vattenburen el. Uppskattningsvis fanns 109 000 småhus med bådevattenburen el och lokaleldstad för biobränsle och ca 118 000 hus bedöms ha haftmöjlighet till oljeeldning (denna grupp har troligtvis minskat ytterligare efter 2006).Bland de elvärmda husen finns också ca 102 000 småhus med frånluftvärmepumpareller luft/vattenvärmepumpar. 365 000 av husen hade en biobränslepanna. Därtillkommer 504 000 hus med direktelvärme, varav ca 292 000 med lokaleldstad.

    Medelförbrukningen för uppvärmning och varmvatten för hus som enbart värms medolja är ca 27 MWh/år, medan motsvarande värde för småhus med vattenburen el är ca15 MWh/år. Småhusen med direktel använder ca 12 MWh/år för uppvärmning ochvarmvatten. Det betyder att ekonomin blir betydligt sämre vid konvertering avelvärmda hus jämfört med oljekonvertering, eftersom energibehovet är lägre samt attinstallationskostnaden kan vara högre.

    En uppskattning av antalet komponenter som inom 10 år kan komma att installeras idessa hus är 213 000 solfångare, 108 000 ackumulatortankar, 106 000 skorstenar,84 000 luftburna pelletkaminer och varmvattenberedare, 40 000 vattenmantladekaminer och 28 000 pannrumspannor. Dessutom tillkommer en utbytesmarknad,kanske speciellt bland husen med biobränslepanna, där gamla pannor byts ut elleräldre människor som tidigare orkat elda med ved till slut byter till pelleteldning.

    Av nybyggda villor uppvärms ca 30 % med el i kombination med biobränsle(troligtvis lokaleldstad) och ungefär lika stor andel värms med enbart vattenburen el(antagligen ofta kompletterat med frånluftvärmepump). Det borde vara av intresse attredan vid nybyggnationen få in integrerade solfångare och pelleteldning i störreutsträckning i nya hus och det kan bli lättare efter att byggreglerna ändras den 1:ajanuari 2010 med en skärpning av kraven för nybyggda hus som använder el föruppvärmning, alltså även el till värmepumpar.

    Potentialen för bio-solsystem till flerbostadshus och lokaler är begränsad då 86 % avflerbostadshusen och nära 70 % av lokalerna värms med fjärrvärme. Det fanns år2006 ca 6200 lokaler med oljeeldning, 4600 lokaler med vattenburen elvärme och5700 lokaler med direktverkande elvärme. I lokalerna som redovisas av SCB ingårinte tillverkande industri. För lägenheter i flerbostadshus gäller att ca 42 000lägenheter värms med enbart olja, 44 000 lägenheter med olja och värmepump,48 000 lägenheter använder direktel och 31 000 lägenheter vattenburen el.

    Fulltekst (pdf)
    fulltext
  • 160.
    Niklasson, Fredrik
    et al.
    SP Energiteknik, Borås.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Marknadspotential för sol- och biovärmesystem2010Rapport (Annet vitenskapelig)
    Abstract [sv]

    I denna rapport analyseras marknaden för kombinerade sol- och pelletsystem, med fokus påsmåhus. Syftet är att presentera antalet objekt inom olika kategorier av hus och värmesystemsom kan vara intressanta för konvertering till bio-sol system samt att ge en uppskattning avårliga uppvärmningsbehov inom respektive kategori.

    Energistatistik från Statistiska centralbyrån (SCB) har använts i kombination med tidigarestudier av byggnadsbestånd och byggnadsutformning. Dessutom har information inhämtatsfrån olika branschorganisationer.

    Från föreliggande genomgång står det klart att den största potentialen för bio-sol systemfinns på villamarknaden både för helt nya system och för kompletteringar till befintliga system.År 2006 fanns det 775 000 småhus med vattenburen värme varav ca 183 000 hade vattenburenel. Uppskattningsvis fanns 109 000 småhus med både vattenburen el och lokaleldstadför biobränsle och ca 118 000 hus bedöms ha haft möjlighet till oljeeldning (dennagrupp har troligtvis minskat ytterligare efter 2006). Bland de elvärmda husen finns också ca102 000 småhus med frånluftvärmepumpar eller luft/vattenvärmepumpar. 365 000 av husenhade en biobränslepanna. Därtill kommer 504 000 hus med direktelvärme, varav ca 292 000med lokaleldstad.

    Medelförbrukningen för uppvärmning och varmvatten för hus som enbart värms med olja ärca 27 MWh/år, medan motsvarande värde för småhus med vattenburen el är ca 15 MWh/år.Småhusen med direktel använder ca 12 MWh/år för uppvärmning och varmvatten. Det betyderatt ekonomin blir betydligt sämre vid konvertering av elvärmda hus jämfört med oljekonvertering,eftersom energibehovet är lägre samt att installationskostnaden kan vara högre.En uppskattning av antalet komponenter som inom 10 år kan komma att installeras i dessahus är 213 000 solfångare, 108 000 ackumulatortankar, 106 000 skorstenar, 84 000 luftburnapelletkaminer och varmvattenberedare, 40 000 vattenmantlade kaminer och 28 000 pannrumspannor.Dessutom tillkommer en utbytesmarknad, kanske speciellt bland husen medbiobränslepanna, där gamla pannor byts ut eller äldre människor som tidigare orkat elda medved till slut byter till pelleteldning.

    Av nybyggda villor uppvärms ca 30 % med el i kombination med biobränsle (troligtvis lokaleldstad)och ungefär lika stor andel värms med enbart vattenburen el (antagligen oftakompletterat med frånluftvärmepump). Det borde vara av intresse att redan vid nybyggnationenfå in integrerade solfångare och pelleteldning i större utsträckning i nya hus och det kanbli lättare efter att byggreglerna ändras den 1:a januari 2010 med en skärpning av kraven förnybyggda hus som använder el för uppvärmning, alltså även el till värmepumpar.

    Potentialen för bio-solsystem till flerbostadshus och lokaler är begränsad då 86 % av flerbostadshusenoch nära 70 % av lokalerna värms med fjärrvärme. Det fanns år 2006 ca 6200lokaler med oljeeldning, 4600 lokaler med vattenburen elvärme och 5700 lokaler med direktverkandeelvärme. I lokalerna som redovisas av SCB ingår inte tillverkande industri. Förlägenheter i flerbostadshus gäller att ca 42 000 lägenheter värms med enbart olja, 44 000lägenheter med olja och värmepump, 48 000 lägenheter använder direktel och 31 000 lägenhetervattenburen el.

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  • 161.
    Nouvel, Romain
    et al.
    ZAFH.
    Cotrado, Mariela
    ZAFH.
    Bertesina, Diego
    Manens.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Birchal, Sarah
    Fedrizzi, Roberto
    D4.2 Assessed Standardised Energy Generation and Energy Distribution Packages2016Rapport (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 162.
    Nyirenda, Elvis
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Conjunctive Operation of Hydro and Solar PV Power with Pumped Storage at Kafue Gorge Power Station (Zambia)2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report covers the work carried out to redesign the two existing conventional hydro power stations in Zambia on the Kafue river into the pumped storage facility with solar photovoltaic power so that security of supply and water conservation is achieved to reduce the power deficits during the dry and drought periods. The two stations are Kafue gorge upper power station (KGUPS) and Kafue gorge lower power station (KGLPS) with an installed capacity of 990 MW and 750 MW respectively. These two stations are dammed hydro power station with the reservoirs size of 785 106 m3 and 80 106 m3 respectively and situated on the 9000 hectares of land with the net head of 400 m. The two plants are situated 15 kilometres apart and the water inflow in the KGUPS is dependent on the water release from the holding dam Ithezi- thezi (ITT dam) situated 220 kilometres from the KGUPS dam. The work covered the sizing of the storage dams and determining the autonomy days needed in order to keep the station (KGUPS) running with minimal impact on power blackouts which were calculated at 5 days considering the size of the dam and the available energy. The financial calculation for the PV system was also carried out in this study except for the hydro system which was not carried out due to the time allocated to conduct this study. The proposed operation scheme for the two hydro stations and the solar PV system is also carried out in order to increase solar power penetration in the Zambian grid, reduce power deficit and conserve water during the days/times with enough solar power.

     

    Designing of the system was carried out using Homer Pro software on which the hydro power station was modelled using the water influx into the turbines at KGUPS, the plant net head of 400 meters was also used with the calculated head losses of 7 % for the 4 meter diameter penstock between KGUPS dam, KGUPS machine hall to the KGLPS dam. The KGUPS dam was modelled as a natural battery so that charging is done using the water from the KGLPS dam, the battery with a total annual capacity of 428 GWh was modelled. PVsyst and PVGIS software tools were also used to simulate the production from the optimised PV system so that the accuracy of tools can be compared.

     

    To cover the load of 777 MW/day (18.6 GWh/day), the available power to provide the necessary energy for the pumps was 270 MW as surplus power from the hydro power machines at KGUPS .The available power from solar PV plant of 236 MW maximum was achieved from the optimized 300 MW PV plant in the dry period of the day which occurs in the month of October, with 300 MW converter , 8 % penetration of solar into the Zambian grid and the pumping scheme was able to provide 589 hours of autonomy with 80 % average state of charge. The total maximum power of 390 MW was good enough to provide power to the two pumps of each 165 MW. From the simulations carried out in the increment of solar PV system from 50 MW to 350 MW, the reliance on hydro power can be reduced drastically and power deficits due to the drought situation as the case for the year 2016 can be alleviated. 300 MW PV plant was selected in order to match with the available land, machines to work as pumps and the initial investment cost to be loosely monitored. The optimized 300 MW PV system with the life of 30 years had a project capital cost of $113 million united states dollars with the levelized cost of electricity 0.0487 $/kWh. The solar PV plant has a payback period of 9 years considering the yearly production from solar PV of 534 GWh as simulated from Homer, PVGIS interactive tool gave an output of 491 GWh. Pumped hydro systems has the capability of utilizing the already existing structures like dams and turbines. They also have the capability of stabilizing the grid network and allow easy penetration of renewable energy technologies like wind and solar. With the government of Zambia pushing for more renewables in the grid by 2030, a pumped hydro project at KGUPS will certainly be able to stabilize the grid and provide a scheme that will be able to push thermal plants to run at full capacity and the efficiency can be improved. In accordance with the IEC TC (technical committee) [30] pumped hydro energy storage is a mature bulk energy technology offering stability and allowing the penetration of intermittent renewables like wind and solar.

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  • 163.
    Ochs, Fabian
    et al.
    Univeristy of Innsbruck.
    Fedrizzi, Roberto
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Dermentzis, Georgios
    Univeristy of Innsbruck.
    D6.7 Guidelines on Systemic Approach and Checklist2016Rapport (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 164.
    Ollas, Fredrik
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Kling, Mattias
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Analys av ett mikronät vid Ihushi Development Center i Tanzania2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna studie omfattar en undersökning om hur ett hybridnät har fungerat, i

    detta fall Ihushi Development Center som ligger I Tanzania.

    De mätningar som har gjorts, har följt en standard för att kunna universellt

    användas vid en fortsatt studie eller direkt kunna användas för att jämföras

    med andra hybridnät med liknande uppsättning och förutsättningar.

    Under arbetets gång så har en ny modell tagits fram för att smidigt kunna

    analysera rådata och uträkning av de nödvändiga parametrarna. Detta

    underlättar även kommande arbeten kring detta hybridnät.

    Det har också blivit en typ av simulering då det har funnits många olika

    typer av utspridda och kontinuerliga fel som har behövts hanteras. Dessa

    värden har då behövts uppskattats utifrån olika källor och metoder, för att

    sedan användas.

    Det har sedan räknats ut effektiviteter och prestanda på olika delar i

    systemet som sedan kommenteras och kan direkt användas för en

    utvärdering i en framtida studie.

    Dessa resultat har bitvis jämförts med tidigare utvärdering men då det

    saknats information från föregående rapport så har en fullständig

    jämförelse och slutsats inte varit möjlig.

    Fulltekst (pdf)
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  • 165.
    Ollas, Patrik
    et al.
    SP Technical Research Institute of Sweden.
    Kovacs, Peter
    SP Technical Research Institute of Sweden.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Testing and evaluation of heat storage tanks according to Eco Design and transitional methods2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In 2013 the Eco Design and Energy Labelling directives for water heaters and for space- and combination heaters came into force as regulations. Additionally, there is the option for “package labels” allowing for various combinations of e.g. solar collectors, boilers and storage tanks to be labelled by the supplier or the dealer. The package is then rated by means of energy calculations based on component data. In late 2013 SP Technical Research Institute of Sweden on behalf of the Swedish Energy Agency conducted a series of tests on five different hot water storage tanks available on the Swedish market for single-family houses. The objectives were to assess the feasibility of the transitional methods for storage testing and to provide an overview of the compliance of storage tanks on the Swedish market compared to the upcoming regulations. The tests were performed according to requirements for hot water stores as well as according to those for water heaters. Results point out some problems with the current methodology and show a need for improvement of tank performance for the tested models as only one out of five tanks got a rating C or better thus complying with the minimum requirements set by the regulation.

  • 166.
    Paavilainen, Janne
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. Chalmers.
    Characterization of Chimney Flue Gas Flows: Flow Rate Measurements with Averaging Pitot Probes2016Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Performance testing methods of boilers in transient operating conditions (start, stop and combustion power modulation sequences) need the combustion rate quantified to allow for the emissions to be quantified. One way of quantifying the combustion rate of a boiler during transient operating conditions is by measuring the flue gas flow rate. The flow conditions in chimneys of single family house boilers pose a challenge however, mainly because of the low flow velocity. The main objectives of the work were to characterize the flow conditions in residential chimneys, to evaluate the use of the Pitot-static method and the averaging Pitot method, and to develop and test a calibration method for averaging Pitot probes for low 𝑅𝑅𝑅𝑅.A literature survey and a theoretical study were performed to characterize the flow conditions in in single family house boiler chimneys. The flow velocities under normal boiler operating conditions are often below the requirements for the assumptions of non-viscous fluid justifying the use of the quadratic Bernoulli equation. A non-linear calibration coefficient is required to correct for these viscous effects in order to avoid significant measurement errors. The flow type in the studied conditions changes from laminar, across the transition regime, to fully turbulent flow, resulting in significant changes of the velocity profile during transient boiler operation. Due to geometrical settings occurring in practice measurements are often done in the hydrodynamic entrance region, where the velocity profiles are neither fully developed nor symmetrical. The predicted changes in velocity profiles are also confirmed experimentally in two chimneys.Several requirements set in ISO 10780 and ISO 3966 for Pitot-static probes are either met questionably or not met at all, meaning that the methods cannot be used as such. The main issues are the low flow velocity, viscous effects, and velocity profiles that change significantly during normal boiler operation. The Pitot-static probe can be calibrated for low 𝑅𝑅𝑅𝑅, but is not reliable because of the changing velocity profiles.The pressure averaging probe is a simple remedy to overcome the problems with asymmetric and changing velocity profiles, but still keeping low the irrecoverable pressure drop caused by the probe. However, commercial averaging probes are not calibrated for the characterized chimney conditions and the information available on the performance of averaging probes at low 𝑅𝑅𝑅𝑅 is scarce. A literature survey and a theoretical study were done to develop a method for calibrating pressure averaging probes for low 𝑅𝑅𝑒 flue gas flows in residential chimneys.The experimental part consists of constructing a calibration rig, testing the performance of differential pressure transducers, and testing a prototype pressure averaging probe. The results show good correlation over a wide operation range, but the low 𝑅𝑅𝑅𝑅 characteristics of the probe could not be identified due to instability in the chosen pressure transducer, and temperature correlation for one of the probes while not for the other. The differential pressures produced are close to the performance limitations of readily available transducers and it should be possible to improve the method by focusing on finding or building a suitable pressure transducer. The performance of the averaging method can be improved further by optimizing the geometry of the probe. Another way of reducing the uncertainty would be to increase the probe size relative to the conduit diameter to produce a higher differential pressure, at the expense of increasing the irrecoverable pressure drop.

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  • 167. Pan, S
    et al.
    Xiong, Y
    Han, Y
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Xia, L
    Wei, S
    Wu, J
    Han, Mengjie
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    A study on influential factors of occupant window-opening behavior in an office building in China2018Inngår i: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 133, s. 41-50Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Occupants often perform many types of behavior in buildings to adjust the indoor thermal environment. In these types, opening/closing the windows, often regarded as window-opening behavior, is more commonly observed because of its convenience. It not only improves indoor air quality to satisfy occupants' requirement for indoor thermal comfort but also influences building energy consumption. To learn more about potential factors having effects on occupants' window-opening behavior, a field study was carried out in an office building within a university in Beijing. Window state (open/closed) for a total of 5 windows in 5 offices on the second floor in 285 days (9.5 months) were recorded daily. Potential factors, categorized as environmental and non-environmental ones, were subsequently identified with their impact on window-opening behavior through logistic regression and Pearson correlation approaches. The analytical results show that occupants' window-opening behavior is more strongly correlated to environmental factors, such as indoor and outdoor air temperatures, wind speed, relative humidity, outdoor FM2.5 concentrations, solar radiation, sunshine hours, in which air temperatures dominate the influence. While the non-environmental factors, i.e. seasonal change, time of day and personal preference, also affects the patterns of window-opening probability. This paper provides solid field data on occupant window opening behavior in China, with high resolutions and demonstrates the way in analyzing and predicting the probability of window-opening behavior. Its discussion into the potential impact factors shall be useful for further investigation of the relationship between building energy consumption and window-opening behavior.

  • 168. Pan, Song
    et al.
    Du, Saisai
    Wang, Xinru
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Xia, Liang
    Liu, Jiaping
    Pei, Fei
    Wei, Yixuan
    Analysis and interpretation of the particulate matter (PM10 and PM2.5) concentrations at the subway stations in Beijing, China2019Inngår i: Sustainable cities and society, ISSN 2210-6707, Vol. 45, s. 366-377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The particulate matters (PM10 and PM2.5) inside urban subway stations greatly influence indoor air quality and passenger comfort. This study aims to analyze and interpret the concentrations of PM10 and PM2.5, measured in several subway stations from October 9th to 22nd, 2016 in Beijing, China. The overall methodology was based on the Statistical Package for Social Science (SPSS) software while General linear model (GLM) and correlation analysis were further applied to examine the sensitivities of different variables to the particle concentrations. The data analysis showed the average overall mass ratio of PM concentrations inside subway station is about 68.7%, much lower than outdoor condition (79.6%). In the areas of the station hall and platform, the real-time PM10 and PM2.5 concentrations varied periodically. In working and operation offices, all rooms had much higher PM concentrations than the outdoor environment when its pollution level was level 3, in which the facility room reached the highest level, while the closed meeting room had the lowest. Correlation analysis results indicated that PM10 and PM2.5 concentrations were mutually correlated (average R2 = 0.854), and a strong linear correlation (R2 = 0.897) of the subway-station PM concentrations to the outdoor PM conditions, regardless of the outdoor atmospheric PM concentrations pollution level was. Nevertheless, the impact of passenger number and temperature & humidity on the station PM concentrations was less, when compared to the outdoor environment. This paper is expected to provide useful information for further research and design of effective prevention measures on PM in local subway stations, towards a more sustainable and healthier built environment in the city underground. 

  • 169. Pan, Song
    et al.
    Pei, Fei
    Wang, Hongwei
    Liu, Jiaping
    Wei, Yixuan
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Li, Guoqing
    Gu, Yaxiu
    Design and experimental study of a novel air conditioning system using evaporative condenser at a subway station in Beijing, China2018Inngår i: Sustainable cities and society, ISSN 2210-6707, Vol. 43, s. 550-562Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Air conditioning system (AC) contributes significantly to the energy consumption of underground metros. In China, most metro stations are designed with water-cooling centralized air conditioning (WC-AC) system, it has been found that several serious problems are brought by this conventional system, such as large space occupying, water leaking, cooling tower noise and low system efficiency. In order to solve these problems, a novel energy-efficient AC system incorporating an independent evaporative condenser (EC) has been proposed and installed at Futong metro station in Beijing, China. A series of pilot measurements were conducted to analyze the cooling performance and energy consumption of this novel EC-AC system. During the testing period, the average refrigeration efficiency of COP, SCOP and ACOP in A and B side is up to 3.8/3.9, 3.4/3.4 and 2.5/2.3. At the same time, some operation problems such as unbalanced working condition have been identified during measurement. The research indicates that such EC-AC system could be a feasible solution to enhance the energy efficiency and reduce the operational costs and carbon emission in metro stations.

  • 170. Pan, Song
    et al.
    Wang, Xingru
    Wei, Shen
    Xu, Chuanqi
    Zhang, Xingxing
    University of Nottingham.
    Xie, Jingchao
    Tindall, Jess
    de Wilde, Pieter
    Energy waste in buildings due to occupant behaviour2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 2233-2238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Occupants’ behaviour has a significant impact on the energy performance of buildings. A good understanding of how occupants use a building provides a possibility of promoting the building's energy efficiency through changing occupant behaviour. Building simulation has been adopted as a useful method by building engineers for quantifying the effects of changing occupant behaviour on the building's energy consumption and indoor environment. However, due to the lack of real measured data with respect to how occupants use the building, such simulation work has relied on assumed behavioural patterns, which significantly reduces the reliability of the predicted results. This paper describes a longitudinal study monitoring occupants’ heating, window opening and cooling behaviour in an office building throughout summer, transitional and winter periods. These behavioural data were then used to drive dynamic building performance simulation to predict the energy saving potential of changing behaviour. Comparison with predicted results by assumed behavioural patterns reflected that improperly assumed behavioural patterns may either overestimate or underestimate the energy saving potential of changing behaviour, especially for unextreme behaviours.

    Fulltekst (pdf)
    fulltext
  • 171. Pan, Song
    et al.
    Wang, Xinru
    Wei, Yixuan
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Gál, Csilla V
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Rend, Guangying
    Yan, Da
    Yong, Shi
    Wu, Jinshun
    Liu, Jiaping
    Cluster analysis for occupant-behavior based electricity load patterns in buildings: a case study in Shanghai residences2017Inngår i: Building Simulation, ISSN 1996-3599, E-ISSN 1996-8744, Vol. 10, nr 6, s. 889-898Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In building performance simulation, occupant behavior contributes to large uncertainties, which often lead to considerable discrepancies between actual energy consumption and simulation results. This paper aims to extract occupant-behavior related electricity load patterns using classical K-means clustering approach at the initial investigation stage. Smart-metering data from a case study in Shanghai, China, was used for the load pattern analysis. The electricity load patterns of occupants were examined on a daily/weekly/seasonal basis. According to their load patterns, occupants were categorized as (a) white-collar workers, (b) poor or older families and (c) rich or young families. The daily patterns indicated that electricity use was much more random and fluctuated over a wide range. Most households of the monitored communities consumed relatively-low electricity; the characteristic double peak with higher level of consumption in the morning and evening were only apparent in a relatively small subset of residents (mostly white-collar workers). The weekly analysis found that significant load shifting towards weekend days occurred in the poor or old family group. The electricity saving potential was greatest in the white-collar workers and the rich or young family groups. This study concludes with recommendations to stakeholders utilizing our load profiling results. The research provides a rare insight into the electricity-use-related occupant behaviors of Shanghai residents through the case study of two communities. The findings of the study are also presented in a meaningful way so that they can directly aid the decision-making of governments and other stakeholders interested in energy efficiency. The research results are also relevant to the building energy simulation community as they are derived from observations, and thus can have the potential to improve the efficiency and accuracy of numerical simulation results.

  • 172.
    Pande, Sohum
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bhaladhare, Raj
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Different Photovoltaic Penetration Rates for the Planned Area of Jakobsgardarna in Borlange, Sweden2018Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The municipality of Borlange is planning to build a new modern, social and an ecologically sustainable district due to an increase in the city’s population. Over 1200 homes shall be built for people from all sections of the society. Due to such high levels of migration into the city, it is of utmost importance for the society to ensure that all the new constructions would be energy efficient and focused towards the goal of creating a sustainable society. The main objective of this study is to understand the importance of planning for Photovoltaics (PV) in new areas and performing a series of simulations for different scenarios with varying degrees of PV penetration for the planned residential area of Jakobsgardarna in Borlänge, Sweden.

     

    This was achieved by determining the load profiles for all buildings by thorough investigation over the previous works in the analysis of household demand loads and calculating the available roof area in several orientations with the help of model maps drawn to scale. Due to varied types of roofs and their structures, it was assumed that all buildings have a similar roof structure i.e. tilted roofs having a tilt of 30°. Batch simulation was performed in PVSyst for a base case scenario which provides the reference point for determining the total PV power and the total PV output in all orientations.

     

    The PV penetration is measured in terms of energy by dividing the total PV output with the annual demand load. Various scenarios of PV penetration are created based on the available roof areas at particular roof orientations. It can be observed that the level of PV penetration is highly dependent on the orientation of roofs. A 17% of PV penetration is observed when PV is installed only on South-facing roofs while the PV penetration reduces drastically to 9% when PV is installed only on East-West facing roofs even though there isn’t a linear reduction in the available roof area.

     

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  • 173.
    Perers, Bengt
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    An improved dynamic solar collector model including condensation and asymmetric incidence angle modifiers2010Konferansepaper (Fagfellevurdert)
    Fulltekst (pdf)
    Collector model Eurosun 2010
  • 174.
    Perez de la Mora, Nicolas
    Högskolan Dalarna, Akademin Industri och samhälle, Maskinteknik. Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Energy Storage for a Grid-Connected PV-System: A Feasibility Study2013Independent thesis Advanced level (degree of Master (One Year)), 12 poäng / 18 hpOppgave
    Abstract [en]

    The work presented in this thesis concerns the dimensioning of an Energy Storage System (ESS) which will be used as an energy buffer for a grid-connected PV plant. This ESS should help managing the PV plant to inject electricity into the grid according to the requirements of the grid System Operator. It is desired to obtain a final production not below 1300kWh/kWp with a maximum ESS budget of 0.9€/Wp. The PV plant will be sited in Martinique Island and connected to the main grid. This grid is a small one where the perturbations due clouds in the PV generation are not negligible anymore.

    A software simulation tool, incorporating a model for the PV-plant production, the ESS and the required injection pattern of electricity into the grid has been developed in MS Excel. This tool has been used to optimize the relevant parameters defining the ESS so that the feed-in of electricity into the grid can be controlled to fulfill the conditions given by the System Operator. The inputs used for this simulation tool are, besides the conditions given by the System Operator on the allowed injection pattern, the production data from a similar PV-plant in a close-by location, and variables for defining the ESS. The PV production data used is from a site with similar climate and weather conditions as for the site on the Martinique Island and hence gives information on the short term insolation variations as well as expected annual electricity production. The ESS capacity and the injected electric energy will be the main figures to compare while doing an economic study of the whole plant. Hence, the Net Present Value, Benefit to Cost method and Pay-back period studies are carried on as dependent of the ESS capacity.

    The conclusion of this work is that it is possible to obtain the requested injection pattern by using an ESS. The design of the ESS can be made within an acceptable budget. The capacity of ESS to link with the PV system depends on the priorities of the final output characteristics, and it also depends on which economic parameter that is chosen as a priority.

    Fulltekst (pdf)
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  • 175.
    Perman, Karin
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Hedlund, G.
    Örebro university.
    WREF 2012: Gender, ethnicity and energy use in multi-family houses - Swedish norms in a multi-etnic context2012Inngår i: World Renewable Energy Forum, WREF 2012, Including World Renewable Energy Congress XII and Colorado Renewable Energy Society (CRES) Annual Conference / [ed] Cheryl Fellows, American Solar Energy Society , 2012, Vol. 3, s. 1834-1840Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to present data and analysis of an investigation of a renewal project in a big public housing area in a Swedish municipality. The project will combine the creation of at better quality of daily life in the multi- family housing area with the aim to reduce energy consumption. The area is in great need of renewal. We study the interaction between technological and social activities. Our theoretical approach in this study is the concept gendered.

  • 176.
    Persson, Björn
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Design and Implementation of a Supervisory Controller for PV and Storage2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Battery energy storage systems are a key factor for enabling a continuous increase of the fraction of photovoltaics in the Swedish electricity grid. One big challenge is to utilise all potential services of such a storage system. The aim of this study was to improve the supervisory controller for an existing battery storage and photovoltaic solution marketed by the Swedish company Ferroamp AB. This has been done by developing a combined peak reduction and time-of-use bill management algorithm, together with a simulation and evaluation software for optimisation of algorithm parameters. The algorithms and tools were evaluated using an installation made by Ferroamp AB and Vattenfall Eldistribution AB as a case study. Sensitivity analyses has been performed on economic parameters and length of the algorithm training data set. Improvement of economic profit, in this case study, were 300 % compared to the currently used algorithm and 32 % compared to a conventional threshold peak reduction algorithm. Despite this improvement, the battery energy storage system is shown to be non-profitable, with the economic profit only covering 36 % of the investment costs, not taking interest rate into account. Like in many other studies, power storage was found more profitable than energy storage. An increase of the grid power tariff and the grid energy fee of 30 % to 40 % is found to make the system viable. One interesting finding is that by using the proposed optimal algorithm, 55 % of the cycle life of the battery storage is still accessible for other services when considering 10 years of economic depreciation time for the system.

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  • 177.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Miljöteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Combined solar and pellet heating systems for single-family houses: How to achieve decreased electricity usage, increased system efficiency and increased solar gains2006Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In Sweden, there are about 0.5 million single-family houses that are heated by electricity alone, and rising electricity costs force the conversion to other heating sources such as heat pumps and wood pellet heating systems. Pellet heating systems for single-family houses are currently a strongly growing market. Future lack of wood fuels is possible even in Sweden, and combining wood pellet heating with solar heating will help to save the bio-fuel resources. The objectives of this thesis are to investigate how the electrically heated single-family houses can be converted to pellet and solar heating systems, and how the annual efficiency and solar gains can be increased in such systems. The possible reduction of CO-emissions by combining pellet heating with solar heating has also been investigated. Systems with pellet stoves (both with and without a water jacket), pellet boilers and solar heating have been simulated. Different system concepts have been compared in order to investigate the most promising solutions. Modifications in system design and control strategies have been carried out in order to increase the system efficiency and the solar gains. Possibilities for increasing the solar gains have been limited to investigation of DHW-units for hot water production and the use of hot water for heating of dishwashers and washing machines via a heat exchanger instead of electricity (heat-fed appliances). Computer models of pellet stoves, boilers, DHW-units and heat-fed appliances have been developed and the parameters for the models have been identified from measurements on real components. The conformity between the models and the measurements has been checked. The systems with wood pellet stoves have been simulated in three different multi-zone buildings, simulated in detail with heat distribution through door openings between the zones. For the other simulations, either a single-zone house model or a load file has been used. Simulations were carried out for Stockholm, Sweden, but for the simulations with heat-fed machines also for Miami, USA. The foremost result of this thesis is the increased understanding of the dynamic operation of combined pellet and solar heating systems for single-family houses. The results show that electricity savings and annual system efficiency is strongly affected by the system design and the control strategy. Large reductions in pellet consumption are possible by combining pellet boilers with solar heating (a reduction larger than the solar gains if the system is properly designed). In addition, large reductions in carbon monoxide emissions are possible. To achieve these reductions it is required that the hot water production and the connection of the radiator circuit is moved to a well insulated, solar heated buffer store so that the boiler can be turned off during the periods when the solar collectors cover the heating demand. The amount of electricity replaced using systems with pellet stoves is very dependant on the house plan, the system design, if internal doors are open or closed and the comfort requirements. Proper system design and control strategies are crucial to obtain high electricity savings and high comfort with pellet stove systems. The investigated technologies for increasing the solar gains (DHW-units and heat-fed appliances) significantly increase the solar gains, but for the heat-fed appliances the market introduction is difficult due to the limited financial savings and the need for a new heat distribution system. The applications closest to market introduction could be for communal laundries and for use in sunny climates where the dominating part of the heat can be covered by solar heating. The DHW-unit is economical but competes with the internal finned-tube heat exchanger which is the totally dominating technology for hot water preparation in solar combisystems for single-family houses.

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  • 178.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Dishwasher and washing machine heated by a hot water circulation loop2007Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 27, nr 1, s. 120-128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electric energy (70-90%) used by electrically heated dishwashers and washing machines is used for heating the water, the crockery, the laundry and the machine and could as well be replaced by heat from other sources than electricity. This article evaluates prototypes of a dishwasher and a washing machine, where the machines are heated by a hot water circulation loop and the heat is transferred to the machines via a heat exchanger. The machine therefore uses water from the cold water pipe. Measurements and simulations have been performed showing that all energy for heating can be replaced if the supply water temperature is 65-70 degrees C. An alternative and common way to save electricity is to connect the machines to the domestic hot water pipe, but the electrical savings with this measure are much smaller, especially for the dishwasher. Computer modelling has been performed and the model has proved to have a high agreement with measured data. However comparison with manufacturers' data indicates that the computer models overestimate the energy demand by about 10 %.

  • 179.
    Persson, Tomas
    Högskolan Dalarna, Akademin Industri och samhälle, Miljöteknik. KTH, Energiteknik.
    Elbesparing med pelletkaminer och solvärme i direktelvärmda småhus2004Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The aim of this study was to investigate how electricallyheated houses can be converted to using wood pellet and solarheating. There are a large number of wood pellet stoves on themarket. Many stoves have a water jacket, which gives anopportunity to distribute the heat to domestic hot water and aradiator heating system.

    Three typical Swedish houses with electric resistanceheating have been studied. Fourteen different system conceptsusing wood pellet stoves and solar heating systems have beenevaluated. The systems and the houses have been simulated indetail using TRNSYS. The houses have been divided in up to 10different zones and heat transfer by air circulation throughdoorways and open doors have been simulated. The pellet stoveswere simulated using a recently developed TRNSYS component,which models the start- and stop phases, emissions and thedynamic behaviour of the stoves. The model also calculates theCO-emissions. Simulations were made with one stove without awater jacket and two stoves with different fractions of thegenerated heat distributed in the water circuit.

    Simulations show that the electricity savings using a pelletstove are greatly affected by the house plan, the systemchoice, if the internal doors are open or closed and thedesired level of comfort. Installing a stove with awater-jacket connected to a radiator system and a hot waterstorage has the advantage that heat can be transferred todomestic hot water and be distributed to other rooms. Suchsystems lead to greater electricity savings, especially inhouses having a traditional layout. It was found that not allrooms needed radiators and that it was more effective in mostcases t use a stove with a higher fraction of the heatdistributed by the water circuit.

    The economic investigation shows that installing a woodpellet stove without a water jacket gives the lowest totalenergy- and capital costs in the house with an open plan (fortoday's energy prices and the simulated comfort criteria). Inthe houses with a traditional layout a pellet stove givesslightly higher costs than the reference house having onlyelectrical resistance heating due to the fact that less heatingcan be replaced. The concepts including stoves with a waterjacket all give higher costs than the reference system, but theconcept closest to be economical is a system with a bufferstore, a stove with a high fraction of the heat distributed bythe water circuit, a new water radiator heating system and asolar collector.

    Losses from stoves can be divided into: flue gas lossesincluding leakage air flow when the stove is not in operation;losses during start and stop phases; and losses due to a highair factor. An increased efficiency of the stoves is importantboth from a private economical point of view, but also from theperspective that there can be a lack of bio fuel in the nearfuture also in Sweden. From this point of view it is alsoimportant to utilize as much solar heat as possible. Theutilization of solar heat is low in the simulated systems,depending on the lack of space for a large buffer store.

    The simulations have shown that the annual efficiency ismuch lower that the nominal efficiency at full power. Thesimulations have also shown that changing the control principlefor the stove can improve efficiency and reduce theCO-emissions. Today's most common control principle for stovesis the on/off control, which results in many starts and stopsand thereby high CO-emissions. A more advanced control varyingthe heating rate from maximum to minimum to keep a constantroom temperature reduces the number of starts and stops andthereby the emissions. Also the efficiency can be higher withsuch a control, and the room temperature will be kept at a moreconstant temperature providing a higher comfort.

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  • 180.
    Persson, Tomas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Manikandan, Gokula
    Measurements of heat losses and energy labelling of storage tanks from Olle Jonsons Mekaniska, Hedemora2016Rapport (Annet vitenskapelig)
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  • 181.
    Persson, Tomas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Nygren, Julia
    Validering av värmeväxlare Ekoflow mot mätdata i laboratoriemiljö2019Rapport (Annet vitenskapelig)
    Abstract [sv]

    Ekoflow avloppsvärmeväxlare från Isakssons återvinner värme ur avloppsvatten och förvärmer inkommande kallvatten eller levererar värme till en värmepump som höjer temperaturen ytterligare. Konstruktionen har funnits på marknaden sedan 1970-talet och installerats främst i flertal badhus och sportanläggningar. Ett teoretiskt beräkningsverktyg har utvecklats av ÅF och syftet med detta arbete har varit att validera beräkningsverktyget mot mätdata. Det finns också ett ”internet-beräkningsverktyg” som inte brukar användas för detaljerad dimensionering. Dess överensstämmelse har också undersökts.

     

    En Ekoflow värmeväxlare med längden 2 meter av typ 2:4 med fyra stråk har installerats i energilaboratoriet vid Högskolan Dalarna och prestandan har uppmätts med rent vatten strömmandes på båda sidorna. Kallvattnet har tagits direkt från nätet och inloppstemperaturen har varierat mellan 7 °C och 10 °C. Inloppstemperaturen på varma sidan av värmeväxlaren har aktivt styrts till 25 °C, 30°C och 35 °C. I alla mätpunkter har flödena hållits så lika som möjligt på båda sidor av värmeväxlaren (balanserat flöde).

     

    Mättiden för varje mätpunkt har varat från ca 10 till 15 minuter, men betydligt längre för punkter med låga flöden då det tar längre tid att uppnå stationära förhållanden. En utvald stabil period av dessa data har medelvärdesbildats för att skapa en stationär mätpunkt. Från uppmätta flöden och temperaturer beräknas värmeutbytet i värmeväxlaren med hänsyn till temperaturberoende densitet och värmekapacitet. Medelvärdet av värmeutbytet beräknat på de båda sidorna användes vid jämförelser med beräkningsmodellen.

     

    Överensstämmelsen mellan mätdata och de två beräkningsverktygen (valideringen) kontrollerades genom att jämföra och redovisa överförd uppmätt värmeeffekt med den värmeeffekt som beräknas med modellen för aktuella flöden och temperaturer. Ingående vattentemperaturer och flöden matades in i beräkningsverktygen och beräknad effekt jämförs mot uppmätt effekt.

     

    Beräkningsverktyget underskattar den verkliga värmeöverföringen (värmeeffekten) med mellan 10 % och upp till 50 % vid låga flöden. Det råder ganska god överensstämmelse mellan mätdata och beräkningsverktyget för högre flöden (mer turbulens). Större avvikelser erhålls vid låga hastigheter och laminärt flöde än vid höga hastigheter. Internetberäknings-verktyget underskattar värmeöverföringen med mellan 50 % och 80% över mätområdet. Så som beräkningsverktygen är utformade kan de alltså ge en viss överdimensionering framförallt vid låga flöden, men det kan också misstänkas att böjar ökar värmeöverföringen.

     

    Försök att kalibrera beräkningsverktyget genom att optimera a- och b-parametrarna ger inte önskad effekt, eftersom det inte går att öka värmeöverföringen enbart vid låga flöden. Mätningarna identifierar framförallt ett flödesberoende, men även ett visst temperaturberoende. En framkomlig väg för att kalibrera modellen kan vara att identifiera a-parametrar för olika mätpunkter och sedan skapa en ekvation som beräknar a-parametern som funktion av flöde och temperatur.

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  • 182.
    Persson, Tomas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Stavset, Ole
    SINTEF Energy Research.
    Ramstad, Randi Kalskin
    NTNU , Department of Geology and Mineral Resources Engineering.
    Alonso, Maria Justo
    SINTEF Energy Research.
    Lorenz, Klaus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Software for modelling and simulation of ground source heating and cooling systems2016Rapport (Annet vitenskapelig)
    Abstract [en]

    The aim of this survey is to explore different simulation software for designing of ground source heating systems. Models to simulate borehole storages, heat pumps, and system components like water storages, hydraulics and building loads are explored. This study is based on a literature survey of software and models for simulation of geothermal heating and cooling systems with focus on vertical ground heat exchangers. The study focus on the software used by the authors, which are EED, TRNSYS, Polysun, Modelica, IDA ICE, and Matlab/Simulink+Carnot.  The scopes and limitations of the software and models are evaluated and the advantages and disadvantages with the software are addressed.  It was found that the user-friendliness is strongly linked to the level of flexibility in the models. Higher flexibility usually means less user-friendliness and more time to learn the tool. EED, Polysun and IDA are considered to be the more user friendly softwares, while Modelica, TRNSYS and Matlab/Simulink+Carnot are considered to be the more flexible softwares. The models covering most of the aspects of borehole simulations are the TRNSBM-model in TRNSYS and the “INTERACT 2016” model for Modelica.

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  • 183.
    Persson, Tomas
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Wiertzema, Holger
    Win, Kaung Myat
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Modelling of dynamics and stratification effects in pellet boilers2019Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 134, s. 769-782Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimizing solar and pellet heating systems can be performed by system simulations in TRNSYS. However; this requires detailed boiler models that can properly model the thermal behaviour of the boilers, such as stratification and thermal response. This study uses a combination of existing models for modelling of the pellet burner part (TRNSYS Type 210) and the water volume (TRNSYS Type 340). This approach addresses the thermal dynamics and internal stratification more accurately than other available models. The objectives of this work are to develop a method for parameter identification for the model and to validate this method and the model itself. Sets of parameters are identified for two pellet boilers and one pellet stove with a water jacket (extended room heater) and the model is validated with a realistic dynamic operation sequence. The results show that modelling of stratification is essential in order to model the true behaviour of residential boilers. The test sequences used were adequate to parameterise the models and to provide the desired accuracy, except regarding the heat losses to room air. The model shows good accuracy for a stove and one boiler, but slightly worse performance for the other boiler regarding dynamics and modelling of the stratification.

    Fulltekst tilgjengelig fra 2021-01-01 15:49
  • 184.
    Pius Perangatt, George
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Evaluating the Economic Feasibility of Utilizing Power Optimizers in Various PVSystems2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Integration of power optimizers in photovoltaic systems is standard practice in some parts of the world. Manufacturers claim that optimizers can significantly reduce electrical losses due to shading. Hence, it is important to investigate this claim and determine under what conditions it is economically warranted to utilize optimizers.

    In this thesis systems were modelled in PVSyst, for 6 different locations: Abu Dhabi, Borlänge, Madrid, New Delhi, Sydney, and Vienna. In each location there were 3 types of systems: a regular non-optimised system, a SolarEdge optimised system and a TIGO optimised system. Each of these systems had 10 variants where the amount of shading was varied. The system variants were simulated in PVSyst and the effect of power optimizers on electrical losses due to shading was analysed. Afterwards, payback periods were calculated for each system to determine under which conditions power optimizers are economically feasible.

    It was found that power optimizers significantly reduce electrical losses due to shading. In some scenarios, the losses were reduced by up to 58 %. However, in the current economic climate in 2018, it is not feasible to incorporate power optimizers, in photovoltaic systems in Abu Dhabi, New Delhi or Sydney. Furthermore, in Borlänge, Madrid, and Vienna, optimizers are only feasible if there are high levels of shading, which is not realistic for a regular photovoltaic system.

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  • 185.
    Poppi, Stefano
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Techno-economic analysis of a novel solar thermal and air-source heat pump system2016Konferansepaper (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    This paper presents a techno-economic analysis of a novel solar thermal and air source heat pump system. The system was designed for relatively high operating temperatures in the space heating circuit and included the use of a heat pump with vapor injection cycle and vacuum insulation on the storage tank. The system model was validated against measurements in laboratory and simulated in TRNSYS 17. Annual simulations were performed for the combination of two climates (Carcassonne and Zurich) and two house standards (SFH45 and SFH100) and the best results were achieved for the boundary conditions the system was designed for. For those conditions (Zurich and SFH100), the novel system showed potential for being cost-effective compared to state of art solar and heat pump system. The “additional investment limit”, i.e. the maximum extra investment cost for the novel system in comparison to a state of art benchmark system that gives a break even result for a period of 10 years, varied between 827 € and 2482 € depending on electricity price. The results of a sensitivity analysis showed that variations in electricity price affected the additional investment limit far more than the other economic parameters

  • 186.
    Poppi, Stefano
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. KTH.
    Sommerfeldt, N.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Madani, H.
    Lundqvist, P.
    Techno-economic review of solar heat pump systems for residential heating applications2018Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 81, s. 22-32Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solar heat pump systems (SHPs) have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many review articles have been published on the subject, however literature discussing the techno-economics of different solar technologies (thermal, photovoltaic and hybrid thermal/photovoltaic) in combination with heat pumps is lacking, and thus to directly compare the merits of different SHPs is not an easy task. The objectives of this study are: a) review the different system boundaries and the main performance indicators used for assessing energetic and economic performances; b) review techno-economic studies in the literature and identify which studies give enough information and are compatible enough for making an economic inter-comparison; c) present an economic inter-comparison based on the identified systems. The results show that there is a lack of studies including an economic assessment of solar photovoltaic and heat pump systems. Additionally, there are no consistent boundaries or approaches to the study structures, making comparisons between systems difficult. In conclusion, a standardized or broadly accepted definition of technical and economic performance for SHPs is needed. Despite this, the study has shown that there are clear trends for decreasing payback times for SHPs, both solar thermal (ST) and photovoltaic (PV), with decreasing heating degree-days and with increasing solar resource.

  • 187.
    Psimopoulos, Emmanouil
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. Uppsala universitet.
    Leppin, Lorenz
    Luthander, Rasmus
    Uppsala universitet, Fasta tillståndets fysik.
    Bales, Chris
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Control algorithms for PV and Heat Pump system using thermal and electrical storage2016Inngår i: Proceedings of the 11th ISES EuroSun 2016 International Conference on Solar Energy for Buildings and Industry, Palma de Mallorca, Spain, 11-14 October 2016, International Solar Energy Society , 2016Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this study a detailed model of a single-family house with an exhaust air heat pump and photovoltaic system is developed in the simulation software TRNSYS. The model is used to evaluate three control algorithms using thermal and electrical storage in terms of final energy, solar fraction, self-consumption and seasonal performance factor. The algorithms are tested and compared with respect to energetic improvement for 1) use of the heat pump plus storage tank for domestic hot water and space heating, 2) use of the electrical storage in batteries and 3) use of both electrical and thermal storage. Results show the highest increase of self-consumption to 50.5%, solar fraction to 40.6% and final energy decrease to 6923 kWh by implementing the third algorithm in a system with 9.36 kW PV capacity and battery storage of 10.8 kWh. The use of electrical energy storage has higher positive impact compared to the thermal storage with the settings and component sizes used. The combined use of thermal storage and batteries leads to final energy savings that are nearly the same as the combined savings of thermal storage and batteries separately, showing that they are mostly independent of one another for the settings of this study.

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  • 188.
    Puhakka, Fredrik
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Lund, Simon
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Energy focus in the building process2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Residential buildings have served as homes for the humankind throughout the years and the energy focus is relatively new in comparison. The interest of the energy perspective has increased alongside with the stricter laws and goals in the European Union and the Swedish Building Board. In multiple cases, the calculated energy usage of the buildings are usually lower than the real time measured energy consumption, showing the importance of performing energy follow-ups of the buildings. The goal of this thesis is revolving around the understanding of the the problems, performance and importance of energy follow-ups in the building process. This study will only focus on the energy focus of residential buildings in the building process, while only taking the Swedish laws into consideration. A literature study was performed as an intention to understand the subject and its problems more thoroughly. The literature study contains the Swedish laws regarding the subject, the structure of the building process and possible failure points, while also looking at multiple studies regarding the difference between the calculated and the measured values. Furthermore, inquiries were sent out to multiple municipalities and companies with questions related to the subject.

    In the answers from the different respondents, the result showed that both municipalities and companies stores energy statistics in web-based programs and requires real measurements to perform energy follow-ups. One municipality describes that there was a vague understanding of the consequences or penalties of not performing an energy follow-up according to the time-plan. Furthermore, the company A described that there was a lack of knowledge of how or where measurements should be performed in detail and where responsibility should be placed if not everything is fulfilled according to the contract. The companies set up their own local goals that surpasses the rules of the BBR and the companies very rarely breaks the energy limits. Company B has only failed to meet the energy limits once and that project was sold off to another actor. Company B also describes that they have never failed to perform an energy follow-up according to the time-plan and doesn’t know what to do if it would happen. Another municipality refers multiple times to their goals regarding the climate and energy limits, however, the methodology on how to achieve these goals aren’t described. Lastly, the there’s no form of cooperation between the municipalities or the companies.

    Differences in energy performance, between the calculated and the real, is often a result of many different factors, which is not always easy to define. Throughout the building process, it is of high importance to keep focus on the energy question in every step. Good and correct knowledge has to be present the whole process to give the best prerequisites for a good performing building. Bad energy performance leads to higher cost for the habitants. Loose terms in laws and regulations can lead to bad energy calculations and leave room for influencing the calculation to show wanted results. Good energy declarations require proper measurements and as the standard equipment today provides somewhat lacking data with monthly values, which makes it difficult to study the reasons to higher energy consumption. For better understanding abnormal energy consumption, more detailed values are often necessary. In terms of applicability, this study can contribute to the awareness to the different issues that has occurred from the study, for example the required education and the responsibility in more detail. A few conclusions can be made from this study, the lack of knowledge in terms of responsibility, consequences or penalties and how measurements should be made in detail. Another conclusion are that web-based programs are used for energy follow-ups and require real values and there’s no cooperation between different actors related to this subject.

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  • 189. Qiu, Zhongzhu
    et al.
    Zhao, Xudong
    Li, Peng
    Zhang, Xingxing
    University of Hull.
    Ali, Samira
    Tan, Junyi
    Theoretical investigation of the energy performance of a novel MPCM (Microencapsulated Phase Change Material),slurry based PV/T module2015Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 87, s. 686-698Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aim of the paper is to present a theoretical investigation into the energy performance of a novel PV/T module that employs the MPCM (Micro-encapsulated Phase Change Material) slurry as the working fluid. This involved (1) development of a dedicated mathematical model and computer program; (2) validation of the model by using the published data; (3) prediction of the energy performance of the MPCM (Microencapsulated Phase Change Material) slurry based PV/T module; and (4) investigation of the impacts of the slurry flow state, concentration ratio, Reynolds number and slurry serpentine size onto the energy performance of the PV/T module. It was found that the established model, based on the Hottel–Whillier assumption, is able to predict the energy performance of the MPCM slurry based PV/T system at a very good accuracy, with 0.3–0.4% difference compared to a validated model. Analyses of the simulation results indicated that laminar flow is not a favorite flow state in terms of the energy efficiency of the PV/T module. Instead, turbulent flow is a desired flow state that has potential to enhance the energy performance of PV/T module. Under the turbulent flow condition, increasing the slurry concentration ratio led to the reduced PV cells' temperature and increased thermal, electrical and overall efficiency of the PV/T module, as well as increased flow resistance. As a result, the net efficiency of the PV/T module reached the peak level at the concentration ratio of 5% at a specified Reynolds number of 3,350. Remaining all other parameters fixed, increasing the diameter of the serpentine piping led to the increased slurry mass flow rate, decreased PV cells' temperature and consequently, increased thermal, electrical, overall and net efficiencies of the PV/T module. In overall, the MPCM slurry based PV/T module is a new, highly efficient solar thermal and power configuration, which has potential to help reduce fossil fuel consumption and carbon emission to the environment.

  • 190.
    Quintana, Samer
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Building integrated photovoltaic (BIPV) modelling for a demo site in Ludvika based on building information modelling (BIM) platform2018Independent thesis Advanced level (degree of Master (Two Years)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis aims to design and simulate a building integrated photovoltaic (BIPV)

    system for three demo buildings in Ludvika, Sweden, which is part of the Energy-

    Matching’s project under the European H2020 research scheme. A literature

    review was firstly conducted in the area of energy scenarios, engineering tools,

    methodologies and the workflows in design and building energy modelling. Then,

    this thesis developed the three-dimensional (3D) building models of the demo

    site, based on the Revit – a building information modelling (BIM) tool. Next, the

    PVSITES tool was considered as the main approach to simulate and optimize the

    BIPV system. Results on the energy output of the dedicated BIPV system, as well

    as financial costs, were finally obtained. It was found that the optimal location for

    the BIPV system was on the three buildings south and east faced roofs, with a total

    area of approximately 800 meters squared (m2) and a yearly irradiance potential

    between 1020 kilowatts hours per meter squared (kWh/m2) and 925 kWh/m2

    respectively. The simulation showed that this BIPV system of 615 m2 with a power

    of 36 kilowatts-peak (kWp) could yield a maximum of 29,000 kilowatts hours per

    year (kWh), a 5% of the total yearly energy demand of the building and over the

    summer, this percentage increases considerably. With the estimated standards

    costs, the BIPV system have a 12 years payback period and 61% investment ratio

    over a 20 years period, concluding that a BIPV system on the Ludvika demo

    building is a feasible project, in terms of energy potential and as well as

    economically. This thesis also concludes that performing the BIPV simulation on

    the BIM platform is both reliable and flexible, and also has the potential to be

    reused, refined and scaled up.

    Fulltekst (pdf)
    fulltext
  • 191.
    Ramaswamy Iyyaswamy, Prashanth
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Performance Analysis of a Building Integrated Photovoltaic System in Norway2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis, performance of the PV system on the facade of the Oseana building is

    evaluated. The thesis was done at the Institute for Energy Technology (IFE), which is

    situated in Kjeller, Norway. The building of the PV system that is being analyzed in this

    thesis is situated in Osøyro, Os Kommune, which is located south of Bergen. The analysis

    was carried out by modelling the building and the PV system in PVsyst, a software package

    specifically used for sizing, simulation and analysis of complete PV systems. Simulations

    were performed on user-defined models based on the original system, whilst considering

    different cases, the results from these simulations were compared to the inverter output

    data, and conclusions were derived.

    The building with the PV system under study has a unique architecture, having a curved

    facade with the panels mounted on this curved facade. The facade also has a walkway

    coming out of the third floor window, which causes shading. The effects of the shading

    caused by the walkway were analyzed. Simulations were carried out for different cases and

    the results were compared to derive conclusions.

    Different weather data sources were considered and used in the base simulations to

    identify the most relevant data source. Once the best data source was identified, further

    simulations were carried out to generate outputs such as the system’s annual yield, losses

    and performance ratio. These simulation outputs were then compared with the actual

    annual outputs of the system. The performance ratios of the simulated systems, with and

    without the walkway are obtained and a comparison between them is made. The probable

    values of global horizontal irradiance are calculated and these values were compared with

    the annual yield of the system to check if the data would match. Probability simulations

    were also carried out to determine the percentage chance that the system would yield a

    certain output value in any given year. Furthermore, the orientation of the PV plane of the

    PV system was changed by altering the tilt angles

  • 192.
    Ramírez Villegas, Ricardo
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik. University of Gävle.
    Eriksson, O.
    Olofsson, T.
    Environmental payback of renovation strategies in a northern climate-the impact of nuclear power and fossil fuels in the electricity supply2019Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 13, nr 1, artikkel-id 80Artikkel i tidsskrift (Fagfellevurdert)
    Fulltekst (pdf)
    fulltext
  • 193.
    Rasch, André
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Utvärdering av Ngenic Tune: Smart styrning av värmesystem i småhus2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In 2016, the global energy consumption was represented to 20 % by buildings, where energy use supplied heating, cooling, lightning and water heating. For the following years until 2040, global energy consumption is expected to grow 48 %, which in turn make demand for energy efficient measures. For the years of 2030 as well 2050, the EU-commission have set up climate goals to reduce global greenhouse gas emissions. Along with this were presented strategies for meeting future climate goals, where one strategy is about increasing overall energy efficiency, which includes buildings. One way of increasing building energy efficiency is through implementation of smart heating control, a cost-effective solution which through a retrofitting measure may reduce building energy consumption. For this paper, a smart thermostat named Ngenic Tune was implemented into a selection of single family houses in Borlänge district heating network. The purpose was to study improvements in thermal comfort and reduction of return temperature from domestic substations. Through a combined survey-interview study of Ngenic Tune users, the study revealed promising potentials for large scale implementation of the technology. The smart thermostat also showed tendency of lowering the return temperature.

    Fulltekst (pdf)
    fulltext
  • 194.
    Reitz, Linda
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Planning and visualization of energy-efficient container buildings for residential purposes under three climatic conditions2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Shipping containers that can no longer be used in cargo transportation are accumulating in large numbers in ports all over the world. At the same time, the usage of fully modular and prefabricated components in the construction sector is on a constant rise in recent years. Reusing these containers in their current form without melting them down, significantly elevates their lifetime usage as well as opens new and interesting options for modular buildings.

    While there are already many container buildings worldwide, the area of energy-efficient container houses has hardly been touched. Therefore, the goal of this thesis is to show the usage of shipping containers to plan energy efficient buildings in three different climate zones, while each building itself is fully climate adaptable for its location using passive architecture.

    To accomplish this primary focus, a detailed analysis of the climate conditions of the locations is necessary. The tree locations are Stockholm, Berlin, and Cape Town. Afterwards a uniform base model will be developed, depending on the specifications of these shipping containers. This Base Case can be adapted to three different climate conditions, by modification and adaptation to create buildings with an effective passive architecture for each location’s climate conditions. These modifications will be used to develop a suitable design for each climate zone with all specifications described and visualized for each case of usage.

    Fulltekst (pdf)
    fulltext
  • 195. Ren, Guangying
    et al.
    Sunikka-Blank, Minna
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    The Influence of Variation in Occupancy Pattern on Domestic Energy Simulation Prediction: A Case Study in Shanghai2017Konferansepaper (Fagfellevurdert)
  • 196. Ren, Guangying
    et al.
    Sunikka-Blank, Minna
    Zhang, Xingxing
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Young urban households in Shanghai, China: characteristics of energy use and attitudes2020Inngår i: Sustainable cities and society, ISSN 2210-6707Artikkel i tidsskrift (Fagfellevurdert)
  • 197.
    Rizos, Konstantinos
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Design Synthesis and Characterization of New Hybrid Derivatives for Dye Sensitized Solar Cells (DSSCs) Based on Porphyrin Rings2015Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Sunlight is the most abundant and one of the cleanest sources of energy. Nature harnesses solar energy very efficiently via the photosynthetic process. A tremendous effort has been expended at learning from natural photosynthesis and creating artificial systems for solar energy applications based on porphyrins that are key light – absorber components of successful solar cells. Dye-sensitized solar cells (DSSCs) establish an innovative class of hybrid organic-inorganic solar cells. The device consists of a mesoporous film of titanium dioxide (TiO2) nanoparticles, coated with a dye monolayer. The role of the dye in DSSCs is similar to the role of chlorophyll in plants and its presence guarantees the sensitivity of the DSSC in the visible part of the solar spectrum, by gathering solar light and transferring the energy via electron transfer to an appropriate material to produce electricity. To date the highest solar energy to electricity conversion efficiencies have reached ~13%. The principal aim of this thesis is the synthesis and characterization of new porphyrin bioinorganic sensitizers for DSSCs. The synthesis part has used a modified synthetic approach by the Coutsolelos group that has successfully produced a new porphyrin product. The base porphyrin was prepared by the trifluoroacetic acid (TFA) catalyzed condensation following a modified procedure. The porphyrin was purified by silica gel column chromatography using dichloromethane. Metallation of porphyrin by Zn was done in the chloroform–methanol mixture followed by the chromatographic purification. The new porphyrin product was subsequently characterized with Ultraviolet – Visible (UV-VIS), Nuclear Magnetic Resonance (NMR), and Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) spectroscopies that have verified the formation of the end product. The characterization shows that the new synthesized porphyrin has characteristics very similar to that of the porphyrin complex with the record efficiency of 13%.

  • 198.
    Romero Suarez, Ivan Jesus
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    AESCU-BIKE design, implementation and testing2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The AESCU-BIKE project is a cargo bike which has an inbuilt off-grid photovoltaic and a monitoring system. The off-grid photovoltaic system consists of a PV module, a lithium-ion battery, a lead acid battery, a charge controller and an electrical fridge. The PV module produces electrical energy which is used to cover the demand of an electrical fridge to supply enough cooling to store and transport pharmaceutical at temperature ranges between 0 °C and 8 °C within the city of Ulm. The monitoring system acquires, saves and plot information regarding the performance of the AESCU-BIKE such as voltages, currents, irradiance, temperatures, location and speed.  The first aim is to theoretically estimate the performance of the off-grid photovoltaic system during summertime and verify that the off-grid photovoltaics system components match. The second aim is to experimentally verify the theoretical estimation of the off-grid photovoltaic system performance during summertime by designing and implementing a monitoring system. The third aim is to visualize in real time information regarding the performance of the AESCU-BIKE. This information is used for an instant analysis of both transportation quality and correct functionality of the off-grid photovoltaic system. A user interface is programmed by using the software Nodered which can be installed in any smart device such as a computer, a smartphone or a Raspberry Pi.  Three different tests are performed to experimentally verify the theorical estimation of the off-grid photovoltaic system performance during summertime. Information such as PV module electrical energy production, fridge electrical energy demand, fridge temperature, ambient temperature, location and speed are plotted and analyzed using the software Excel.  After the results analysis, it is concluded that the monitoring system provides essential information to validate theoretical estimations and to deeply understand the behavior of the off-grid photovoltaic system. Regarding the PV module electrical energy production, losses related to the lack of a MPPT, not optimal PV module inclination angle and shading effect are clearly understood. Regarding the fridge electrical power demand, it is shown that the energy demand is highly related with the ambient temperature. The user interface makes the entire system more friendly. The instant visualization of the measurements helps the user to relate the physical phenomena with the system behavior.

    Fulltekst (pdf)
    fulltext
  • 199.
    Rozas Barrio de Mendoza, Andrés Arturo
    Högskolan Dalarna, Akademin Industri och samhälle, Energiteknik.
    Design, Implementation and Performance Evaluation of an Off-grid Photovoltaic Powered Grain Mill without Battery Storage Master2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Many rural communities in developing countries still do not have access to electricity, however, inhabitants of those communities must still perform energy demanding activities. Such is the case of milling grains to fulfill their food intake. This activity, in many cases, is still performed manually.

    This research project aims in providing a solution to the aforementioned problem by designing, implementing and testing a grain mill powered solely by means of photovoltaic energy. It is intended to avoid the use of an intermediate battery in order to reduce the initial and possible running costs of the solution.

    The project development included testing the operation of the mill under different speeds and loads to acknowledge the torque profile and accurately size the corresponding motor. A brushless direct current motor together to its speed controller was selected to drive the mill. The operation of the mill was tested under constant and variable power source to characterize the electrical performance and size a suitable photovoltaic module. Also, the quality of the flour and output rate were analyzed.

    A modified maximum power point tracker controller was designed and implemented based on a microcontroller (Arduino Uno board). The perturb and observe as well as the incremental conductance maximum power point tracking methods were implemented and analyzed to be used as the basis of the modified tracking algorithm.

    The overall performance of the designed controller was evaluated using a modified test procedure based on the EN 50530 standard, which indicates how to evaluate the static and the dynamic efficiency of the maximum power point trackers in grid connected inverters.

    The proposed controller achieved an average static efficiency of 47 % while milling corn and 55 % while milling wheat, based on the weighting factors defined in the European efficiency. Moreover, the controller reached an average dynamic efficiency of 50 % while milling corn and 62 % while milling wheat during the test with irradiance change from medium to high levels (300 W/m2 to 1000 W/m2). Finally, the average flour output rate while milling corn was measured as 3.25 kg/h while milling corn and 5.38 kg/h while milling wheat.

  • 200.
    Rönnelid, Mats
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Fiedler, Frank
    Högskolan Dalarna, Akademin Industri och samhälle, Energi och miljöteknik.
    Reserapport Plataforma SolarAlmeria, 5-8/6 20112012Rapport (Annet vitenskapelig)
    Abstract [sv]

    Reserapporten beskriver verksamheten vid Plataforma Solar Almeria (PSA) i Spanien och diskuterar tänkta samarbetsmöjligheter mellan PSA och Högskolan Dalarna

    Fulltekst (pdf)
    fulltext
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