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  • 1.
    Akhtar, Naeem
    Halmstad University, School of Business, Engineering and Science.
    Analysis of Simris Hybrid Energy System Design and Working and Checking the Effects of Using High Capacity Factor Wind Turbine2019Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    The world is entering the future where integration of renewable energy sources within the power grid will play an important role when facing the challenge of reducing global warming. The intermittent generation characteristics associate with renewable energy sources can be handled by the implementation of microgrids. A Microgrid is a group of energy source (e.g. wind, solar etc) that are located in the same local area that can operate independently in the event of electricity outage and can also be connected to the national grid in case of energy demand exceeds than the energy produced in the same local area. The implementation of microgrid in an electrical distribution system must be well planned to avoid problems. The EU has set high goals to reduce the non-renewable energy sources by 2030. EU has started some local energy systems (microgrids) and Simris is a part of it.

    This study is about a microgrid project at Simris in the south-east of Sweden. The village of Simris has 140 households supplied by a wind turbine of rated power 500kW and a solar power plant of 440 kW rated power. This project is run by E. ON within the framework and collaboration of Interflux, in which several network operators within the EU participate to investigate flexibility options in local energy systems. 

    The aim of this study is to find different scenarios in which the Simris microgrid can be run in islanded-mode. Four different scenarios were investigated, and simulation was done in MATLab. After simulation the results were discussed in the “Analysis and Results” section and the size of the wind turbine, the solar park (PV)and the battery were suggested for each of the scenarios. A short calculation was also included between the installation cost of the suggested wind turbine and the needed battery size. The cost of battery is much higher than the cost of wind turbine, so its beneficial for the economy of the microgrid to have a wind turbine of 1000 kW rated power and battery size 35 MWh rather than using the same old wind turbine of 469 kW rated power and upgrade the battery to 462 MWh. 

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  • 2. Albazi, Waleed
    Smart Student Table2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this study is to develop what is called aStudent table, which is designed specifically for school children in emergency circumstances, so it will be suitable for partial solutions for the problems facing children in refugee camps, who are forced to leave their homes and schools. The idea of the study focuses on the creation of the Student table so that the generation of electricity will be suitable for lighting and illumination with the use of some electronic devices used in daily school needs like laptops, so the solar cell system will be connected to a small generator through a hybrid system. A fully functional prototype has been built as part of the study. When the system works through the hybrid route for lighting and illumination the solar system will generate the power needed and when the sun light disappears the Power can be generated by bike pedals. The generation of electricity by the hybrid system is considered as an effective and environmentally friendly option with economic benefits.

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  • 3.
    Andersson, Martin
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Åhlund, Anton
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Solenergiutveckling i Halland2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Idag ökar antalet solenergianläggningar stort i Sverige, framförallt inom solelen. Samtidigt finns det inte någon långsiktig hållbar metod för att statistikföra solenergin. Det finns heller ingen regionsspecifik statistik, något som många svenska län och kommuner är intresserade av. Med bakgrund till detta behandlar arbetet frågor om solenergins utveckling med utgångspunkt för Hallands län, där fokus ligger på statistikinsamling.

    För att få en god uppfattning om utbyggnaden av solenergi i länet görs en statistiksammanställning av regionens solenergi. Samtidigt läggs förslag på framtida statistikmetoder för att bättre kunna följa solenergins utveckling i framtiden, regionalt såväl som nationellt. En jämförelse med andra län samt Tyskland och Danmark görs för att fånga upp idéer.

    Jämförelsen visar att Tyskland och Danmark idag har mer utvecklade metoder för statistikinsamling av solel medan de likt Sverige, har begränsad solvärmestatistik.

    Även en lönsamhetsberäkning för en mindre privat solcellsanläggning gjordes. Det visade sig vara lönsamt om anläggningen får skattereduktion eller investeringsstöd. Utan ekonomisk hjälp är lönsamheten lägre, även om utsikterna kan ändras beroende på elprisutvecklingen.

    Resultatet av den regionala statistiksammanställningen visar att Halland i början av år 2014 hade 1,6 GWh i årlig energiomvandling för solel respektive 7,3 GWh för solvärme. I länet finns 5,3 W/capita nätansluten solel jämfört med Sveriges 4,2 W/capita, vilket innebär att Halland har 21 % mer installerad effekt än Sverige i genomsnitt.

    De lämpligaste källorna för insamling av solenergistatistik är energibolag och installatörer där en kombination av dessa två källor ger en stor säkerhet och hög täckningsgrad. Finns bara resurser är detta det bästa alternativet. Rapportering går från dagens manuella metod till ett automatiserat system. En viktig ändring blir att rapportering av lokalisering införs vilket medför att regional statistik enkelt kan sammanställas.

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    Solenergiutveckling i Halland
  • 4.
    Andersson, Mikael
    et al.
    Halmstad University, School of Business and Engineering (SET).
    Lingvide, Leo
    Halmstad University, School of Business and Engineering (SET).
    Possibilities for small scale hydropower in Honduras2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With an increased demand of electricity it is in everyone´s interest that investments are made to promote sustainable options, and the question on how to supply clean and sustainable energy is global. In this bachelor’s thesis, funded by SIDA and Åforsk, the intention was to investigate the possibilities for renewable energy in Honduras, a developing country with an expanding energy sector.

    Honduras is Central America´s second largest country, located in-between Guatemala, Nicaragua and El Salvador. The country is one of poorest in the region, and the trade is characterized by the import of oil and export of coffee and fruit.

    Hydropower has played a major role in the development of the Honduran electricity sector, but today oil based thermal power has the largest share of the energy market. It accounts for more than half of the total generation which makes Honduras very vulnerable to changes in the oil price. The remaining share of generation comes from renewable sources, mostly hydropower. The potential for hydropower in Honduras is estimated to be about five times bigger than the current installed capacity. With a constantly rising oil price, building new hydropower or refurbishing old is becoming more and more competitive. This is the reason for this thesis; to investigate the possibilities for small scale hydropower in Honduras. Information has been gathered through contacts with energy organizations as well as examples and experiences from refurbished or upgraded hydropower plants and other relevant hydropower projects. With this information barriers and possibilities in the process of refurbishing, upgrading and building hydropower plants in Honduras have been identified.

    Our conclusion is that developing small scale hydropower in Honduras is very demanding; applying for required permissions, studies, financing, construction etc. are barriers which all require hard work. Considering this we still believe that the possibilities and positive impacts are greater than the barriers and negative impacts when developing small scale hydropower in Honduras thanks to legislated incentives. The positive impacts that can come from building and refurbishing hydropower plants include: cheaper electricity, improved roads, power lines, and schools, promotion of rural electrification and creation of new job opportunities. Small scale hydropower can help Honduras use its natural resources and create a sustainable development for a brighter future.

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  • 5.
    Andersson, Robin
    Halmstad University, School of Business and Engineering (SET).
    Electric power quality in low voltage grid: Office buildings and rural substation2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The modern society uses more and more electronic devices needed to being able to function together. This put higher demands on the electrical grid together with that the typical load have changed from the past. Therefore utility companies are obliged to keep the voltage within certain limits for this to function. What exact these limits have been have not always been clear since they have not been gathered in one single document. 

    This thesis is a cooperation with Kraftringen who also has been the initiator. Kraftringen would like to become more proactive in their work regarding electric power quality. For becoming more proactive continuously measurements have to be done but the locations have to be carefully selected in the beginning to get a wider perspective of the grid.

    Energy markets inspectorate (EI) is supervisory of the electric power quality in Sweden and since 2011 they have published a code of statutes (EIFS 2011:2 later 2013:1) intended to summarize limits on voltage. Some of the electrical power quality aspects are not mentioned in EIFS 2013:1 and standards have to be used to find limited values. Flicker and interharmonics are not mentioned in EIFS 2013:1 and for values on flicker the standard SS-EN 50160 has to be used and for interharmonics the standard SS-EN 61000-2-2 state limit values. Besides all this there are standards with stricter limits than EIFS 2013:1 e.g. for total harmonic distortion on voltage were SS-EN 61000-2-2 suggest 6 % instead of 8 %.

    Three different field studies have been conducted in order to get some perception of the present situation regarding electric power quality. Two measurements were conducted on a typical office building because they represents a large part of the typical load in Lund. The third measurement was conducted on a substation in a rural area to get a perception of the situation outside urban areas. 

    These measurements shown that the overall electric power quality was within given limits according to EIFS 2013:1 and different standards. However, conducted measurements shown some interesting results. Both the typical office buildings have a slightly capacitive power factor which results in that the voltage inside the building is going to be slightly higher than at the substation. Since the voltage level at the measured urban substation was above nominal voltage level with about 2-5 % this could be problematic. Another eventual problem with a load with a capacitive power factor is resonance with the inductive parts of the grid like transformers leading to magnified harmonic levels.

    It is suggested that Kraftringen expand their number of permanent electric power quality measurement locations to get a better overview of the present situation. The best suited locations to start with are such that have received complaints earlier, preferably measured on the low voltage side of the transformer for also register the amount of zero sequence harmonics. Next step in the measurement expansion would be substations known to be under higher load than others or substations with a PEN-conductor in a smaller area than the phase conductors, supplying a typical office load with high amounts of third harmonics and unbalance. From this it would be appropriate to spread out the measurement locations geographically to better get to know the grids behaviour. 

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  • 6.
    Andersson, Robin
    Halmstad University, School of Business and Engineering (SET).
    Risk och sårbarhetsanalys av fjärrvärmenätet i Lund2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Fjärrvärmenätet i Lunds stad började byggas 1963 och består idag av 238 km parvisa fjärrvärmerör. Den teoretiska livslängden för fjärrvärmerör är uppskattad till mellan 50-100 år varför det nu börjar bli dags att reinvestera vissa delar. En tydlig indikering om var på fjärrvärmenätet man ska lägga ekonomiska medel för reinvestering eller underhåll är skadestatistik från olika ledningstyper och fabrikat. Kartläggning av fjärrvärmenätets kompensatorer har genomförts och en riskmatris är framtagen baserad på deras geografiska placering och dimension.

    Resultatet är tänkt att finnas som stöd inför kommande budget på Kraftringen om vilka ledningssträckor som är i störst behov av en reinvestering.

    Grunden i rapporten är hämtad från en forskningsrapport från 1999 med avseende på redan framtagna riskmatriser för ledningstyp och jordart. Riskmatrisen för ledningstyp är modifierad något utefter Lunds lokala skadestatistik för en bättre tillämpning. Skadestatistiken för Lund jämförs med den nationella skadestatistik som Svensk Fjärrvärme samlade in under 1995-2003. Ledningstyper och fabrikat jämförs där den helgjutna betonglådeledningen i Lund uppvisar en betydligt högre skadefrekvens än nationellt. En annan rörledningstyp som sticker med en högre skadefrekvens är direktskummade fasta plastmantelrör av märket Pan-Isovit vilket troligtvis beror på den tidiga utbyggnaden i Lund. Fjärrvärmenätet i Lund var först i Sverige med direktskummade fasta plastmantelrör redan år 1966 av märket Pan-Isovit vilket kan ha föranlett skador på grund av bristande erfarenhet och barnsjukdomar.

    Varje ledningssträcka i den lokala databasen har tilldelats en risk som baseras på riskmatriserna för ledningstyp, jordart samt skadestatistik för berörd typ och konsekvensen av ett avbrott beroende på ledningsdimension. Det ger en indikering på risken för avbrott samt konsekvensen av ett avbrott för olika ledningssträckor, dock utan hänsyn till en eventuell ringmatning.  

    För att en reinvestering ska vara motiverad ska utbytet vara lönsamt. Parametrar som påverkar lönsamheten är värmeförluster, skadefrekvens samt goodwill relativt kunderna. Dessa parametrar är beräknade för samtliga ledningssträckor med befintlig ledning och för reinvestering. Vid värdet ett på goodwill, d.v.s. enbart utebliven försäljning uppnås ingen lönsamhet i en reinvestering för någon ledningssträcka. Det är först vid en goodwill-faktor 8 som lönsamhet uppnås. Ett vanligt värde för goodwill hamnar mellan en faktor 50-100 vilket då gör det lönsamt idag att reinvestera 5,7–8,5 % av fjärrvärmenätet.

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  • 7.
    Antila, Eric
    Halmstad University, School of Business, Innovation and Sustainability.
    SunTrack2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    For many of us, electricity is a natural and necessary source, making it easier to go about our everyday life. Imagine having to collect firewood, for several hours a day, to be able to carry out such a simple task as preparing a meal. For many people, especially in developing countries, everyday life looks just like that, but it does not have to. In line with the increasing demand of sustainability, new technologies now turn their focus to the almost inexhaustible source of energy, namely the sun.

    The energy that is being received every day in the form of solar radiation, corresponds to about 8000 times more energy than what is being consumed on the planet, throughout anentire year. With today's technology, there is now a possibility to farm parts of this energy, to be used as a more sustainable alternative. 

    Sunfurias product uses a technology that, with the help of solar collectors, saves solar energy in a heat storage, enabling cooking at any time.

    For the solar collectors to be as efficient as possible, they need to rotate following the movement of the sun throughout the day. Today, this is done by using an advanced tracking device, which in turn makes the entire product significantly more expensive. Which also affects the sales volume, especially in the developing countries.

    The SunTrack project has been carried out in collaboration with Sunfuria AB to solve the need for a more affordable product, by developing a cost-effective alternative to the current solar tracking system.

  • 8. Aqel, Safaa
    Application of Colored Solar Panels on Municipal buildings in Sweden: The multiple benefits for an Innovative Renewable Society2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to understand how and why the diffusion of colored solar panels take place. A motive for the study is the fact that Sweden needs to reach the goal of a fossil free country by 2045, with one of the sub-goals of solar power contributing to 10 percent of the renewable energy production. Currently, Sweden's electricity production is only at 0.1 percent solar power. I have found that the innovation of colored solar panels could be a factor to contribute to the diffusion and increase in solar power. To analyze this hypothesis, two different methods were used. First, a literature study was conducted where the focus was on the history and diffusion of solar panels, in correlation to the fundamentals of colored solar panels. I also compared the two technologies regarding their efficiency and price, as well as how they differentiate in the market. Second, an interview study was conducted with 17 solar experts working in different cities across Sweden. The experts had different insights to bring from their different positions in the solar power industry. The results showed that standard and colored solar panels are highly interrelated, causing the colored solar panels to always be slightly less efficient than the standard module. The results also suggest that there is a high potential for colored solar panels in the future, and that there is a high need for marketing and reliable companies in order for the diffusion to happen. A major affecting factor for the diffusion of colored solar panels is architects, who have a large input in the design process of municipal buildings. Further research is needed in the development in the standard and colored module, as well as in the stability of colored solar panel companies. 

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  • 9.
    Arvidsson, Ida
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Ringvall, Angelica
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Vindkraftens framtida scenarier2012Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In several countries that have been early in the development of wind farms, there is today a second hand market for the used wind turbines. The European Union (EU) has established a waste hierarchy in order to minimize throwaway mentality. The second hand market is a part of this as the steps are to minimize, reuse, recycle, extract energy and landfill.

    In order to promote the development of renewable energy, there are energy certificates for the producers that provide it, wind power being one type of renewable energy. After 15 years the energy certificates for a specific wind turbine are no longer paid, and after that there are several different scenarios for the wind turbine. The scenarios investigated in this bachelor’s thesis are export of the wind turbine to countries that are not as far along as Sweden in their development towards renewable energy, selling in Sweden to individuals, and recycling of the wind turbine, as it mostly consists of metals and therefore is recyclable. In these three scenarios it is assumed that the sites for wind turbines are being reused for new larger wind turbines that produce more energy. Two additional scenarios are to reduce the number of wind turbines in a wind farm by half, in this way gaining access to free spare parts for the remaining wind turbines and continued operation, i.e. operate them for as long time as possible.

    To assure the decommissioning of the wind turbines and restoration of the site, there are several economical choices for the operator of the wind turbine. No matter what choice is made, the total amount should be 500 000 SEK according to the permission for the wind turbine. A Swedish authority, Miljöprövningsdelegationen, decides whether the operators choice in reassuring and make a decision based on that.

    To see which scenario is most profitable the economical part is crucial in this bachelor’s thesis. As a wind turbine is a large investment, the investment calculation is sensitive even to small changes. Inflation, interest rate, electricity price and energy certificate price can all vary a good deal but as it is almost impossible to predict the development of these factors, the inflation, interest rate and energy certificate price are all on a fixed level in this report. The electricity price is assumed to be dependent of the inflation solely. By using these assumptions and Microsoft Excel it has been clear that selling the wind turbine and reuse the site for a new larger wind turbine is the most profitable.

    Sweden has the goal to have 30 TWh, equivalent to 20 %, electricity from wind until year 2020. Today the part is 6.5 TWh, equivalent to 4 %. To make this goal reality it is necessary to make the permitting process easier and faster than the case is today. If Sweden compares to Denmark they already have 28 % electricity from wind and they aim for 50 %.

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    Vindkraftens framtida scenarier
  • 10. Arvidsson, Karl-Henrik
    et al.
    Kristensen, Sophie
    Reducering av effekttoppar i Halmstads fjärrvärmesystem: Modellering av ett teoretiskt laststyrningsschema2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    On behalf of Halmstads Energi och Miljö (HEM) this paper investigates the possibilities to reduce power peaks in their district heating production through demand side management. The purpose with this paper is to reduce the power peaks with 10 MW and investigate which customers or areas HEM should focus on. In addition, two bottlenecks in the district heating network are analyzed by the effects of demand side management. A theoretical model of demand side management was constructed. The model uses hourly data from production and endeavor to daily average values. The model also included parameters such as storage capacity and manipulated outdoor temperature. The results from demand side management relates to the total daily variations of the district heating system. The demand side management has been applied to a selection of 214 substations and three independent demand side management schemes for the year of 2016, one for each bottleneck and one for the total 214 substations. The choice of substations for demand side management is based on which buildings are connected to them. Criteria for the selection are buildings with high thermal mass, which give high thermal inertia and buildings with high heat demand (large apartment buildings). It is of great interest to investigate how demand side management affects the indoor temperature in selected buildings because limit values cannot be exceeded. The result shows that the power peaks can be reduced by 11.7 MW (mean value) for the whole year excluding the months of spring and summer and for the winter months 13.1 MW (mean value). The reasons why the power peaks can be reduced to a greater extent during the winter months was due to a larger heat demand and heat load variations. Two bottleneck areas applied one theoretic demand side management scheme each where power peaks can be reduced by 0.63 MW(mean value) and 0.7 MW(mean value) excluding spring and summer months and 0.71 and 0.72 only including winter months. The profit from reducing the power peaks for HEM is shorter operating time for the peak heating boilers. The power peaks is later compensated and balanced with renewable bio energy. The simulation from 2016 brings a cost saving to 2.7 million SEK. The profit comprises the cost difference between fossil fuels, natural gas and renewable fuels such as wooden chips. The carbon dioxide reduction during the same period of time was 1671 metric tonne CO2- equivalents.

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  • 11.
    Averfalk, Helge
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS). Lund University, Lund, Sweden.
    Enhanced District Heating Technology: Maintaining Future System Feasibility2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    When heat demand and high temperature heat supply gradually decreases in the future, then it will effect district heating systems ability to compete on the heat market. A good way to mitigate less district heating feasibility is to operate systems with lower temperature levels and the most conceivable way to achieve lower temperature levels is to decrease return temperatures.

    Thus, this thesis emphasise temperature errors embedded in district heating systems. Only a selection of temperature errors are analysed in this thesis. First, the temperature error that occurs due to recirculation in distribution networks at low heat demands. Second, the temperature error that occurs due to hot water circulation in multi-family buildings. Third, the temperature error that occurs due to less than possible heat transfer in heat exchangers, i.e. too short thermal lengths.

    In order to address these temperature errors three technology changes have been proposed (i) three-pipe distribution network to separate the recirculation return flow from the delivery return flow, (ii) apartment substations to eliminate hot water circulation utilisation, and (iii) improved heat exchangers for lower return temperatures at a constant scenario. Analysis of proposed changes has resulted in annual average return temperatures between 17-21 °C.

    Furthermore, rapid introduction of intermittent renewable electricity supply in the energy system has prompted an increased necessity of power system balancing capacities. Large-scale conversion of power-to-heat in electric boilers and heat pumps is a feasible alternative to achieve such balancing capacities. Analysis of the unique Swedish experience with utilisation of large heat pumps installations connected to district heating systems show that since the 1980s 1527 MW of heat power has been installed, about 80 % of the capacity was still in use by 2013. Thus, a cumulative value of over three decades of operation and maintenance exists within Swedish district heating systems.

    The two papers presented in this thesis are related to future district heating systems through the five abilities of fourth generation district heating (4GDH), which are documented in the definition paper of 4GDH.

  • 12.
    Averfalk, Helge
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Faktiska varmvattenflöden i flerfamiljshus2021Report (Other academic)
    Abstract [sv]

    Detta projekt innehåller insamling av mätdata från tappvarmvattenanvändning från flerbostadshus och bearbetning av densamma. Målet med projektet är att undersöka om det finns förutsättningar att korrigera nuvarande norm för dimensionerande flöde för tappvarmvatten. Resultaten påvisar potential att reducera normen för tappvarmvattenflöde.

    Detta projekt består av genomgång samt sammanställning av litteratur för fastställande av dimensionering av tappvarmvattenflöden till i huvudsak flerbostadshus. Därtill har datainsamling samt dataanalys utförts på tappvarmvattenmätningar tillhandahållna av Ngenic AB.

    Studien syftar till att uppdatera dimensionerande varmvattenbehov vid nybyggnation samt att ge råd till varmvattendimensionering i hus för att förbättra precisionen för den dimensionerade kapaciteten. Bättre dimensionering av bland annat ventiler och värmeväxlare ger mindre slitage och därmed längre livslängd men också förbättrad avkylning.

    Insamlad data har olika tidsupplösning: 6-sekunder (clamp-on, ultraljudsteknik), 1-minut och 15 minuter (enstrålig vinghjulsmätare). Mätningarna har skett vid olika tidsperioder där de längsta (1 år) varit för 15-minutersvärden och de övriga varierat runt cirka tre veckor. Därtill har data samlat för en uppsättning flerbostadshus med varierande storlek.

    Efter bearbetning av data görs följande observationer:

    1. 15-minutersvärden är olämpliga för att skatta momentant flöde (l/s)

    2. I storleksordnad jämförelse mellan 15-minuters värden och 6-sekundersvärden erhölls en mycket mindre avvikelse i momentant flöde (l/s) än förväntat.

    3. I storleksordnad jämförelse mellan 1-minutersvärden och 6-sekundersvärden erhölls så pass liten skillnad i momentant flöde (l/s) att dessa två perspektiv uppfattas som utbytbara och att det därmed inte nödvändigtvis föreligger något behov av att mäta med högre tidsupplösning än 1 minut.

    4. 1-minutersvärden för en uppsättning flerbostadshus av varierande storlek indikerar att det finns möjlighet att reducera dimensioneringsförutsättningarna för tappvarmvattenflöden.

    Denna studie verifierar nuvarande utformning av dimensionerande flöde för tappvarmvatten enligt F101. Vidare rekommenderas som en första ordningens anpassning av nuvarande Ekv. (7), där variabel A kan justeras från 2,10 till 0,84.

  • 13.
    Averfalk, Helge
    Halmstad University, School of Business, Innovation and Sustainability.
    IEA Heat Pumping Technologies TCP Annex 57:Flexibility by implementation of heat pumps in multi-vector energy systems and thermal networks: Task 1, Swedish background report2022Report (Other academic)
  • 14.
    Averfalk, Helge
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS). Department of Energy Sciences, Lund University, Lund, Sweden.
    Low-temperature District Heating: Various Aspects of Fourth-generation Systems2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    With decreasing heat demand and less availability of high-temperature heat supply in future energy systems, the current district heating systems may experience increased competition on the heat market. A viable option to mitigate increasing competition is to operate systems with lower temperature levels, and the most conceivable way to achieve lower temperature levels is to decrease return temperatures.In this thesis, aspects of improvements in district heating systems are assessed. Three aspects, in particular, have been analysed. These are integration between energy systems, improvements in heat distribution technology, and economic benefits of low-temperature district heating systems.An increasing interest in integrating different energy systems has been prompted by the rapid introduction of intermittent renewable electricity supply in the energy system. Large-scale conversion of power to heat in electric boilers and heat pumps is a feasible alternative to achieve the balancing capacities required to maintain system functioning. Analysis of the unique Swedish experience using large heat-pump installations connected to district heating systems shows that, since the 1980s, 1527 MW of heat power has been installed, and about 80% of the capacity was still in use in 2013. Thus, a cumulative value of over three decades of operation and maintenance exists within Swedish district heating systems.Increased competition prompted by changes in the operation environment necessitates improved heat distribution. This thesis focuses on three system-embedded temperature errors: first, the temperature error that occurs due to recirculation in distribution networks at low heat demands; second, the temperature error that occurs due to hot-water circulation in multi-family buildings; third, the temperature error that occurs due to lower heat transfer than is possible in heat exchangers (i.e. too-short thermal length). To address these temperature errors, three technology changes have been proposed (i) a three-pipe distribution network to separate the recirculation return flow from the delivery return flow, (ii) apartment substations to eliminate hot-water circulation use, and (iii) improved heat exchangers for lower return temperatures. The analysis of the proposed changes indicates annual average return temperatures between 17°C and 21°C.The final analysed aspect is the economic benefits of low-temperature district heating. It was identified that strong economic motives for lower operating temperatures in future heat supply exist, whereas the economic motives are significantly weaker for the traditional heat supply.The five papers presented in this thesis are related to future district heating systems through the five abilities of fourth-generation district heating (4GDH), which are documented in the definition paper on 4GDH.

  • 15.
    Averfalk, Helge
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Morgondagens effektiva fjärrvärme: En beskrivande litteraturstudie2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is made as a literature review, focusing on the work done to increase understanding of efficiency in the categories of substations and secondary heating systems, with respect to the deviation from the theoretically possible cooling off in the distribution network as well as the economic benefit that appear. The main purpose of a considerable part of the literature used in this report addresses the issue of identifying individual causes of reduced cooling in district heating systems. These literature resources have been compiled and summarized as part of the report.

    The technology of district heating is associated with benefits such as better use of the energy in a fuel. This is the case of cogeneration plants where serial generation of electricity and thermal energy increases efficiency compared with the parallel generation where heat is generated locally and electricity is generated centrally. Serial generation thus allows for lower primary energy demand. Another benefit from combustion in units with higher capacity installed is that a higher control of emission with environmental impact is permitted. Additionally local environment change drastically when a few large supply units replace a large number of local supply units. It has also been shown that district heating can reduce greenhouse gas emissions in a cost efficient way. Thus being a part of the energy system to achieve the EU climate goals

    In Sweden, district heating is developed to a high degree. In connection with decreasing focus on expansion, the focus on maintenance and optimization and how district heating should look like in the future increases. In conjunction with lower heat demand from new and renovated buildings distribution cost will increase. For district heating to maintain competitiveness a development in distribution technology that move toward the next generation of distribution technology is necessary. Average temperatures today in Swedish district heating systems are for supply water 86 ° C and for return water 47 ° C. In the future temperature levels could decrease to current with temperatures down against 55 ° C supply temperature and 25-20 ° C return temperature. The latter system temperature levels moves towards the ideal possible.

    It is possible to distinguish four generations of district heating distribution technology. The differences between generations are essentially depending on temperature levels but also depend on state of matter. The first generation district heating used high-temperature steam for heat transfer and then the newer distribution technologies resulted in lower temperatures and change of phase, from gas to liquid. The third generation of district heating distribution technology meant lower temperature than the second generation, and likewise the fourth generation will have a lower temperature level than the third-generation distribution technology for district heating. The development is driven by the benefits of lower temperature levels. One of the more appealing benefits of lower supply temperature is the possibility to use low exergy heat, resulting in reduced need of primary energy. The potential heat sources where increased heat supply with lower system temperatures becomes available can be seen in the four next bullets.

    • Waste heat
    • Geothermal heat
    • Solar heat
    • Heat pump

    Other advantages obtained with lower temperature levels in heat distribution are.

    • Lower distribution losses
    • Higher electrical power efficiency in CHP
    • Increased efficiency in flue gas condensation
    • Increased capacity in the distribution network
    • Reduced need for pump power in the distribution network
    • Lower risk of serious scalding
    • Increased capacity in heat storage
    • Ability to use other materials for distribution at lower cost

    There seem to be a consensus in the literature that lower temperature levels in district heating systems are a desirable change. The reason for this is likely that there are mostly advantages of lower temperature levels. The drawbacks of lower temperature levels are negligible which make the risk of investment low.

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  • 16.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Benakopoulos, Theofanis
    Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
    Best, Isabelle
    University of Kassel, Kassel, Germany.
    Dammel, Frank
    Technical University of Darmstadt, Darmstadt, Germany.
    Engel, Christian
    Austroflex Rohr-Isoliersysteme GmbH, Perchtoldsdorf, Austria.
    Geyer, Roman
    AIT Austrian Institute of Technology GmbH, Vienna, Austria.
    Gudmundsson, Oddgeir
    Danfoss, Sønderborg, Denmark.
    Lygnerud, Kristina
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Oltmanns, Johannes
    Technical University of Darmstadt, Darmstadt, Germany.
    Nord, Natasa
    Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
    Ponweiser, Karl
    Vienna University of Technology, Vienna, Austria.
    Schmidt, Dietrich
    Fraunhofer IEE, Kassel, Germany.
    Schrammel, Harald
    AEE Intec, Gleisdorf, Austria.
    Skaarup Østergaard, Dorte
    Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
    Svendsen, Svend
    Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
    Tunzi, Michele
    Technical University of Denmark (DTU), Kongens Lyngby, Denmark.
    Werner, Sven
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Low-Temperature District Heating Implementation Guidebook: Final Report of IEA DHC Annex TS2. Implementation of Low-Temperature District Heating Systems2021Report (Other academic)
    Abstract [en]

    This guidebook was written between 2018 and 2021 by seventeen authors that used approximately 15 000 hours of work within the IEA DHC TS2 annex. The content is based on more than 250 literature references and 165 inspiration initiatives to obtain lower temperatures in buildings and heat distribution networks. The author group wrote 40 internal documents about early implementations of low-temperature district heating. Fifteen of these early implementations are presented in this guidebook.The guidebook contains aggregated information about the main economic drivers for low-temperature district heating. It shows how to obtain lower temperatures in heating systems inside existing and new buildings, as well as in existing and new heat distribution networks. An applied study of a campus system in Darmstadt shows the possibility of reducing temperatures in an existing heat distribution network with rather high temperatures. The competitiveness of low-temperature district heating is explored by analysing business models and heat distribution costs. Early adopters of low-temperature district heating are presented by examples and by identified transition strategies. Five groups of network configurations with fourteen variants are presented to be used for low-temperature district heating. Finally, all 165 identified inspiration initiatives and all 137 locations mentioned are listed.

  • 17.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Dalman, Bengt-Göran
    BG Dalman AB, Göteborg, Sverige.
    Kilersjö, Christer
    EKSTA, Kungsbacka, Sverige.
    Lygnerud, Kristina
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS). IVL Svenska Miljöinstitutet, Stockholm, Sverige.
    Welling, Sebastian
    IVL Svenska Miljöinstitutet, Stockholm, Sverige.
    Analys av 4e generationens fjärrvärmeteknik jämfört med 3e generationens: Simulering av sekundärnät i nybyggnationsområde2017Report (Other academic)
    Abstract [sv]

    Bakgrunden till studien är att nya förutsättningar genom energieffektivisering, konkurrens från värmepumpar och nya krav på kundsidan gör en modernisering av fjärrvärmeverksamhet nödvändig. En del av denna modernisering är att kunna dra nytta av de fördelar som lägre temperaturer i näten medför. Därtill skapas genom den nya tekniken förutsättningar för att ta hand om värmekällor som idag inte utnyttjas (t.ex. värme från kylprocesser och annan infrastruktur såsom värme från avloppsvatten och värme från kollektivtrafik).

    Befintlig teknik är beprövad och bygger på att det finns ekonomiska incitament att förbränna biobränsle och avfall. Steget till att pröva en ny teknik där andra värmekällor och en ny gränsdragning gentemot kund blir nödvändig är därför stort och förenat med ett antal frågor. Det är just de frågor som uppkommer i ett fjärrvärmeföretag inför implementering av 4e generationens fjärrvärmeteknik som projektet försöker identifiera. Det blir dock så att enbart en del av frågorna besvaras genom att studien har ett avgränsat fokus. Fokus är på jämförelse mellan ett 3GDHtvårörsystem och ett 4GDH-trerörsystem i ett sekundärnät i ett nybyggnationsområde.

    I projektet simuleras hur utfallet blir för olika parametrar om man hade valt att implementera 4e generationens teknik istället för 3e generationens teknik.

    Resultaten påvisar att:

    • 4e generationens lösning ökar energieffektiviteten i byggnader, detta främst genom att behovet av varmvattencirkulation försvinner.• Beaktas enbart distributionsförluster i näten så är 4e generationen mer effektiv än 3e generationen.• Genom lägenhetsväxlaren i 4e generationens lösning så elimineras risken för Legionella helt. En möjlig barriär för 4e generationens teknik består dock i att boverkets byggregler inte är konstruerade för att varmvattencirkulation inte finns.• Lägenhetsväxlarna innebär en kostnad per lägenhet vilket begränsar lösningens kostnadseffektivitet jämfört med en större värmeväxlare i fastighetens bottenplan. Idag är 4e generationens teknik lämpad för fastigheter med 10-15 lägenheter, är det fler lägenheter blir 4e generationens lösning dyrare än den konventionella 3e generationens lösning.• En viktig aspekt med 4e generationens lösning att värmeförlusten från huset förflyttas från fastighetsägaren till fjärrvärmeföretaget, genom att värmeleverans sker till varje lägenhet och inte vid husvägg. Initialt kan sådan börda på fjärrvärmeföretaget verka negativ med avseende på kostnad. Diskussionerna i projektet mynnade ut i att parterna enas om att affären blir mer rättvisande och att fastighetsägaren får ökad insyn i värmeförbrukningen vilket, med rätt affärsmodell, kan skapa ökat förtroende och en möjlighet att dela på förlusten mellan de två parterna.

    Projektet har omfattat löpande dialog med EKSTAs VD vilket varit värdefullt för att skapa förståelse kring fastighetsägarens perspektiv och frågor rörande 4e generationens teknik. Därtill har en workshop med EKSTAs driftspersonal hållits för att diskutera relevansen i de resultat som tagits fram. I projektet ingår BengtGöran Dalman med över 35 års erfarenhet av fjärrvärmeverksamhet vid Göteborg Energi. Projektets verklighetskoppling leder till slutsatsen att det inte föreligger någon särskild driftsproblematik för implementering av 4e generationens system.

    Som en egen del i projektet uppmärksammas den diskussion som förs i branschen kring möjligheten att dra nytta av billig el, främst under perioder då det blåser mycket och det blir ett överskott av el i elnätet. I studien analyseras möjligheten att inte använda en konventionell pelletspanna som tilläggsvärmekälla utan en eldriven panna. Resultaten visar att med dagens styrning genom skatter och avgifter så är det inte möjligt att dra nytta av att det förekommer perioder med mycket lågt elpris. Rådande regelverk stödjer istället installationer såsom pelletspannor.

    © ENERGIFORSK

  • 18.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Möllerström, Erik
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Ottermo, Fredric
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Domestic hot water design and flow measurements2021In: Energy Reports, E-ISSN 2352-4847, Vol. 7, no Suppl. 4, p. 304-310Article in journal (Refereed)
    Abstract [en]

    In this study, the sizing of primary side components for preparation of domestic hot water are analysed, both qualitatively and based on measurements of domestic hot water demand in one multi-family building with 268 apartments. The collected data spans a period of 18 days during the end of 2020 and is collected in 15-min, 1-min, and 6-s intervals. An overview of the historic development for the design of domestic hot water flow in Sweden is also presented. There is a long-standing argument in Sweden, that the current district heating guidelines result in an overdesign of the flow for domestic hot water. The consequence of this is oversizing heat exchangers and valves in the substations. This study assesses, qualitatively, the issues related to overdesigned primary side valves for preparation of domestic hot water. A revised design for domestic hot water flow for the Swedish context is also conceptualised. The study suggests that an improved design flow for domestic hot water in multi-family buildings can be derived based on empirical measurements. The 15-min intervals are observed to tone down information of peaks to a degree where it is unsuitable to use as basis for a new design flow. The 1-min data does appear to preserve information to a degree where it can be used to assess a design flow when related to data with a 6-s interval. The 6-s data is expected to constitute a resolution that may be less available, and in this study, it constitutes a representation of the real domestic hot water demands. However, to find a fitted curve to empirical data, for the design flow based on number of apartments per multi-family building, the population of datasets needs to be increased. © 2021 The Authors. Published by Elsevier Ltd.

  • 19.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Pipe Sizing for Novel Heat Distribution Technology2019In: Energies, E-ISSN 1996-1073, Vol. 12, no 7, article id 1276Article in journal (Refereed)
    Abstract [en]

    This paper assesses pipe sizing aspects for previously proposed, novel, low heat distribution technology with three pipes. Assessment issues include heat loss, pressure loss, and pipe sizing for different typical pipe configurations. This assessment has been provided by the analysis of a case area with single-family houses. Concerning heat loss, the proposed three-pipe solutions have the same magnitude of heat loss as conventional twin pipes, since lower return temperatures compensate for the larger heat loss area from the third pipe. Regarding pressure loss, the main restriction on the size of the third pipe is limited to the pressure loss in the third pipe. Thermostatic valves to manage the flow rate of the third pipe are advocated, since alternative small pumps have not been found to be commercially available. The pipe sizing recommendation is that the third pipe for recirculation purposes can be two to three standard pipe sizes smaller than the corresponding supply and return pipe, if no prosumer is connected in the heat distribution network.

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    Pipe Sizing for Novel Heat Distribution Technology
  • 20.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Persson, Urban
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Low‐temperature excess heat recovery in district heating systems: The potential of European Union metro stations2020In: Book of Abstracts: 6th International Conference on Smart Energy Systems / [ed] Henrik Lund, Brian Vad Mathiesen, Poul Alberg Østergaard & Hans Jørgen Brodersen, 2020, p. 34-34Conference paper (Other academic)
    Abstract [en]

    This paper presents an assessment of the excess heat recovery potential from EU metro stations. The assessment is a sub-study on low temperature recovery opportunities, explored in the H2020 ReUseHeat project, and consists of spatial mapping of 1994 underground stations with quantitative estimates of sensible and latent heat, monthly and annually, attainable in rejected platform ventilation exhaust air. Being a low-temperature source, the assessment conceptually anticipates recovery of attainable heat with compressor heat pumps to facilitate the temperature increase necessary for utilisation in district heating systems. Further, the paper explores the influence on useful excess heat volumes from low-temperature heat recoveries when distributed at different temperature levels. The findings, which distinguishes available (resource) and accessible (useful) excess heat potentials, indicate an annual total EU28 available potential of ~21 PJ, characterised by a certain degree of seasonal temporality, and corresponding accessible potentials of ~40 PJ per year at 3rd generation distribution, and of ~31 PJ at anticipated 4th generation conditions. Despite lower accessible volumes, utilisation in 4th generation systems are naturally more energy efficient, since relatively less electricity is used in the recovery process, but also more cost-effective, since heat pumps, at lower temperatures, can be operated at capacities closer to design conditions and with less annual deviations.

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    Conference_presentation
  • 21.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Werner, Sven
    Halmstad University, School of Business, Innovation and Sustainability, The Rydberg Laboratory for Applied Sciences (RLAS).
    Economic benefits of fourth generation district heating2020In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 193, article id 116727Article in journal (Refereed)
    Abstract [en]

    The main impetus for lower distribution temperatures in district heating systems is the lower heat supply costs obtained by these lower temperatures. In this paper, the differences in heat supply costs for two different temperature levels have been estimated for various future heat supply options. The estimations were obtained by modelling a district heating system characterised by typical climate conditions for Central Europe. High sensitivity to lower supply costs from lower temperatures was found for geothermal heat, industrial excess heat, and heat pumps, whereas low cost sensitivity was estimated for combined heat and power plants using waste or biomass. Lower heat distribution loss constitutes a minor component of the total cost reductions. The current use of high heat distribution temperatures was identified as an important barrier for the transition to renewable and recycled heat supply in district heating systems. Hence, lower distribution temperatures would facilitate this required transition because lower distribution temperatures provide higher profitability for these renewable and recycled heat sources. © 2019 The Authors. Published by Elsevier Ltd.

  • 22.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Efficient heat distribution in solar district heating systems2018In: SDH Solar District Heating: Proceeding, 2018, p. 63-66Conference paper (Refereed)
    Abstract [en]

    This paper contains a short analysis showing the main benefit for solar district heating when a novel heat distribution concept with low temperatures is applied. The analysis is performed by comparing the annual solar heat output from a solar collector field for current heat distribution temperatures in Sweden with the corresponding output for the novel heat distribution concept. The results show that the new low temperature concept provides 66% more solar heat for a typical solar collector. Hereby, the solar collector field can be reduced with 40%, giving a corresponding cost reduction for solar heat generated. Another result is that the cost gradient for lower costs from lower return temperatures is five times higher for solar district heating compared to current heat supply in Swedish district heating systems. One major conclusion is that high heat distribution temperatures in current European district heating systems are a major barrier for the competitiveness of solar district heating.

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    fulltext
  • 23.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Essential Improvements in Future District Heating Systems2016In: Proceedings of the 15th International Symposium on District Heating and Cooling: September 4th - 7th, 2016, Seoul, South Korea / [ed] Rolf Ulseth & Kyung Min Kim, 2016, p. 194-200Conference paper (Refereed)
    Abstract [en]

    The major common denominator for future efficient fourth generation district heating systems is lower temperature levels in the distribution networks. Higher efficiencies are then obtained in both heat supply and heat distribution. Heat supply becomes more efficient with respect to combined heat and power, flue gas condensation, heat pumps, geothermal extraction, low temperature excess heat, and heat storage. Heat distribution becomes more efficient from lower distribution losses, less pipe expansion, lower scalding risks, and plastic pipes. The lower temperature levels will be possible since future buildings will have lower temperature demands when requiring lower heat demands. This paper aims at providing seven essential recommendations concerning design and construction strategies for future fourth generation systems. The method used is based on a critical examination of the barriers for lower temperature levels and the origins of high return temperatures in contemporary third generation systems. The two main research questions applied are: Which parts of contemporary system design are undesirable? Which possible improvements are desirable? Key results and the corresponding recommendations include temperature levels for heat distribution, recirculation, metering, supervision, thermal lengths for heat exchangers and heat sinks, hydronic balancing, and legionella. The main conclusion is that it should be possible to construct new fourth generation district heating networks according to these seven essential recommendations presented in this paper.

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    fulltext
  • 24.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Essential improvements in future district heating systems2017In: Energy Procedia, ISSN 1876-6102, Vol. 116, p. 217-225Article in journal (Refereed)
    Abstract [en]

    The major common denominator for future efficient fourth generation district heating systems is lower temperature levels in the distribution networks. Higher efficiencies are then obtained in both heat supply and heat distribution. Heat supply becomes more efficient with respect to combined heat and power, flue gas condensation, heat pumps, geothermal extraction, low temperature excess heat, and heat storage. Heat distribution becomes more efficient from lower distribution losses, less pipe expansion, lower scalding risks, and plastic pipes. The lower temperature levels will be possible since future buildings will have lower temperature demands when requiring lower heat demands. This paper aims at providing seven essential recommendations concerning design and construction strategies for future fourth generation systems. The method used is based on a critical examination of the barriers for lower temperature levels and the origins of high return temperatures in contemporary third generation systems. The two main research questions applied are: Which parts of contemporary system design are undesirable? Which possible improvements are desirable? Key results and the corresponding recommendations include temperature levels for heat distribution, recirculation, metering, supervision, thermal lengths for heat exchangers and heat sinks, hydronic balancing, and legionella. The main conclusion is that it should be possible to construct new fourth generation district heating networks according to these seven essential recommendations presented in this paper. © 2017 The Authors. Published by Elsevier

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    fulltext
  • 25.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Framtida fjärrvärmeteknik: Möjligheter med en fjärde teknikgeneration2017Report (Refereed)
  • 26.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Novel low temperature heat distribution technology2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 145, p. 526-539Article in journal (Refereed)
    Abstract [en]

    Lower future heat demands and lower availability of non-fossil high temperature heat supply are expected future market conditions that restrain the long-term viability of contemporary district heating systems. Hence, current district heating technology should be enhanced to increase system performance in new heat distribution areas. This paper aims to outline a proposal for technical improvements required to achieve lower annual average return temperatures in new residential buildings to improve viability in future market conditions. The proposed technical solution consists of three principle changes: three-pipe distribution networks, apartment substations, and longer thermal lengths for heat exchangers. The three technical modifications aims at addressing system embedded temperature errors. Furthermore, a simulation model was developed to assess the proposed technical solution concerning different energy performances of buildings and different thermal lengths in heat exchangers. The results show that implementation of the three technical modifications reaches time-weighted annual average return temperatures of 17–21 °C with supply temperatures of about 50 °C. The results also verify the increased necessity to separate the network return flows into delivery and recirculation flows in residential substations as energy performance in buildings increase.

  • 27.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Felsmann, Clemens
    Technische Universität Dresden, Dresden, Germany.
    Rühling, Karin
    Technische Universität Dresden, Dresden, Germany.
    Wiltshire, Robin
    Building Research Establishment (BRE), Garston, Watford, United Kingdom.
    Svendsen, Svend
    Technical University of Denmark, Kongens Lyngby, Denmark.
    Li, Hongwei
    Technical University of Denmark, Kongens Lyngby, Denmark.
    Faessler, Jérôme
    University of Geneva, Geneva, Switzerland.
    Floriane, Mermoud
    University of Geneva, Geneva, Switzerland.
    Quiquerez, Loïc
    University of Geneva, Geneva, Switzerland.
    Transformation Roadmap from High to Low Temperature District Heating Systems: Annex XI final report2017Report (Other academic)
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  • 28. Axell, Johan
    et al.
    Eriksson, Oliver
    Solcellsprojektering - Blomsterlandet: Beräkning och simuleringsstudie av en solcellsanläggning för optimering av hög andel egenanvänd el2019Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
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  • 29.
    Ayed, Sami
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Assessment of energy losses for the climate shell in a commercial passenger ship2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The shipping industry is facing a major challenge. Current and future emission requirements result in considerably increased operating costs. Studies have shown that it is a large potential to reduce the ship operating costs by energy effectivisation. The focus has naturally been on systems with major energy losses, such as combustion engines, propulsion and hull friction.

    A passenger ship like Stena Danica with a big climate controlled accommodation could be expected to have major heat losses. By calculating transmission losses from walls, ceilings, window sections, and the energy losses by ventilation, a general view of how heat losses are distributed has been established. The primary goal is to gather information that could be useful in further energy improvements.

    Due to lack of information and deficiently measured data have several assumptions and simplifications been made. Despite this, the calculations can be considered as indicative. The results indicated that about 50 percent of the energy losses occur by ventilation and the remaining consists of transmission losses in windows sections and climate shell, (About 25% each). The focus in the calculations has been to estimate the accommodations heating demand. Energy improvements that reduce the heating demand will reduce the cooling demand as well. This may be a greater incentive for measures as the air conditioning system are powered with higher energy quality; electricity. Besides shore power the electricity is mainly generated by diesel generators. The energy used for heating is mainly produced by waste heat or is supplied by shoreside district heating.

    Upgrading the ventilation systems are considered to be the most economic method to reduce the heat losses in the accommodation area. The ship's ventilation systems lack any type of demand control, this causes excessive energy losses as the ventilation demand vary greatly regarding to time of the day and numbers of passengers.

    The ship has a large amount of single pane windows that also contributes to large energy losses. To upgrade or replace these are considered to be more economic than to improve the insulation on the rest of the climate shell as it doesn’t affect the interior to the same extent. The latter may be worth considering in case of a major renovation of the vessel.

  • 30.
    Bengtsson, Conny
    Halmstad University, School of Business and Engineering (SET).
    Ersättning av fossilt bränsle i värmeproduktion: Pulverbrännare till befintliga oljepannor2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We are facing a change, to reduce our dependency on fossil fuels in favor of increased use of renewable energy. Incentives in the form of increased excise taxes on fossil fuels for companies accelerate the conversion to renewable energy or energy efficiency of its production. The consequence is a progressively more expensive cost for district heating with fuel oil to manufacturing industry. Excise tax on fuel oil rises by 41 percent, from 2010 to 2015 for those companies. To convert existing oil boilers with woodpowderburner is a solution to keep production costs down and remain competitive. In this thesis studied the possibility of converting oil boilers in the size range of 5 to 10 MW. The study takes a holistic approach to RMT's district heating to search the answer, if it is possible to do a conversion from a technical, sustainability and economic perspective. The felt need for peak load from oil boilers at -3° C appeared not to sue; it ended up at -6° C. The results indicate that a 10 MW oil boiler can be converted to 5 MW wood powder and while retaining its original power through a combination burner. Previously problems with woodpowderplant are taken care of and reference facilities in the current magnitude are in operation. An inquiry was sent out to get budget prices at a conversion of 5 and 10 MW oil boilers for evaluation. Even though all the suppliers was given the same opportunities so varied budget prices very much. A big surprise was the short payoff time on conversions of small oil boilers. The conversion of a 10 MW OP has a payback period of 20 months and that was rather unlikely before the study was performed. This study can also be seen as a source of inspiration to other companies that have small peak load boilers and want to phase out their fossil fuel dependence with renewable energy, and retain their competitiveness. In the district heating sector, these 5 and 10 MW oil boilers are ordinary peak load boilers. There are about 1000 oil boilers in the size from 5 to 10 MW in Sweden so it should be a large potential in converting oil boilers to wood powder

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    Ersättning av fossilt bränsle i värmeproduktion
  • 31.
    Bengtsson, Niclas
    et al.
    Halmstad University.
    Nilsson, Johan
    Halmstad University.
    Solar Water Pumping for Irrigation: Case Study of the Kilimanjaro Region2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study has been conducted as a Minor Field Study (MFS). It focuses on solar water pumping for small-scale farmers in the Kilimanjaro Region of Tanzania. The purpose is to investigate the possibilities for rural farmers to operate their irrigation with solar power instead of their current option: fossil fuels, primarily petrol. The study was conducted in three phases, starting with pre-study in Sweden, followed by field study in Tanzania from January to March 2015 and finishing with summarizing and calculating in Sweden. Fuel powered water pumping has a cheap capital cost; however, it is expensive and problematic to maintain and operate. Solar powered water pumping is almost completely opposite. It has a higher initial cost; however, it is considerably cheaper to run. The results indicate that the investment in solar power might be too expensive for the farmers, as long as they do not receive external financial and educational support. Assuming that the farmers are able to obtain a solar water pumping system, results show that they will benefit and save a considerably amount of money over a long period of time. Also, solar water pumping is environmentally friendly compared to the systems in Tanzania today. 

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    Solar Water Pumping for Irrigation, Bachelor Thesis
  • 32.
    Bengtsson, Simon
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energy Science.
    Economic and environmental implications of a conversion to natural gas.2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
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  • 33.
    Benyahia, Najat
    Halmstad University, School of Business, Engineering and Science.
    Inverkan på Göteborgs Energi Nät ABs elnät av en ökning av Solcellsanläggningar2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
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  • 34.
    Berg, Nichlas
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Kårhammer, Per
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Säsongslagring av spillvärme: Ersättning av Halmstad fjärrvärmenäts spetslastanläggning2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Sweden, a great deal of energy is used for residential and commercial heating. To fulfill the ever increasingly need for heat, new heating plants is built to complement the district heating system. At the same time there is unused energy in industry, which produces heat as an unwanted byproduct.

    This report evaluates the possibility to use this byproduct to supply energy to a district heating system and store it in seasonal heat storage. When the heat demand increases during the cold season of the year, the seasonal heat storage contributes with heat energy.

    The idea is to replace parts of the heating plants in Halmstad with heat storage and waste heat. The aim is to exclude usage of all fossil fuels. This report will also evaluate the economical prerequisites and environmental benefits in replacing biofuels.

    A steelworks company, Höganäs Halmstadverken, is situated in Halmstad. This industry could contribute with surplus heat, which is calculated in this report.

    With help of calculations and simulations in Microsoft Excel, a system with adequate heat storage method and surplus heat from local industry is formed. This system is optimized concerning economic and environmental matters.

    The results reveal that Halmstad's conditions are favorable to integrate pit heat storage and there is potential to deliver waste heat from Höganäs Halmstadverken steelworks. Sizes of seasonal heat storage is optimized to 200 000 m3 for replacing fossil fuels respectively 550 000 m3 for replacing fossil fuels and biofuels. Waste heat effect is calculated to 15 MW.

    The economical calculations results in an annual profit up to 8 million SEK with a payoff equal to 8 years. The environmental benefits consisting of reduced greenhouse gases are calculated to 4 800 tons carbon dioxide equivalents annually.

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  • 35.
    Bergman, Clara
    Halmstad University, School of Business, Engineering and Science.
    Effekten av en energikartläggning2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Halland's small and medium-sized enterprises, SME’s, have for several years had financial support to carry through energy audits. Region Halland and the Swedish Energy Agency provide the support. So far, the effects of these energy audits have been unknown. Hence the purpose for this study is to explore the effects that the energy audits have had on these enterprises hitherto.

    This study will highlight the benefits that the companies have experienced and analyse changes in energy use and climate benefits. Empirical data has been gathered through existing energy audits, a web-based survey and complemented with in-depth interviews. Calculations have thereafter been made to quantify the effects.

    The survey shows that energy measures affecting the indoor climate are generally the ones implemented. Hence improved indoor climate is a frequent added value. Lower energy use though, is not enough motivation for the companies to take action. It is indicated that energy measures are more likely to be implemented when the current energy systems need upgrading or replacement. To summarise, the energy audits have a positive impact on the companies, also in the long term. The study evinces that it is possible to increase the profitability in a company and yet lower their energy use and climate impact.

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  • 36.
    Bhatti, Harrison John
    et al.
    Halmstad University, School of Business, Engineering and Science, Centre for Innovation, Entrepreneurship and Learning Research (CIEL).
    Danilovic, Mike
    Halmstad University, School of Business, Engineering and Science, Centre for Innovation, Entrepreneurship and Learning Research (CIEL). Shanghai Dianji University, Shanghai, China.
    Making the World More Sustainable: Enabling Localized Energy Generation and Distribution on Decentralized Smart Grid Systems2018In: World Journal of Engineering and Technology, ISSN 2331-4249, Vol. 6, no 2, p. 350-382Article in journal (Refereed)
    Abstract [en]

    Smart grid is an idea of upgradation of the traditional electric grid infrastructure. The efficiency of the existing electrical grid can be automated by integrating with innovative technical equipment such as: high-tech forecasting system, digital sensors, advanced two-way communication and two-way power flow systems. Smart grid establishes an interface between utility and consumer which helps to use energy, based on the preferences of price, eco-friendly and without technical system issues. It empowers the grid to be more secure, reliable and efficient. The peer-reviewed articles and published government reports have been reviewed, based on the analysis of technical characteristics of power generation systems, eco-friendly sources of power generations, cost reduction, functionality and design of traditional grid versus smart grid. Furthermore, the innovative technologies that enable the grid to integrate with decentralized power generation system efficiently have been considered. This paper claims that in this modern era, it is arduous for traditional grid to fulfill the rising demand of electricity, along with sustainable, eco-friendly and stable power supply, as it cannot be efficiently integrated with decentralized and localized power generation systems and renewable energy sources. The result of this paper shows that decentralized and localized power generation systems are located close to end-users which decrease the transmission and supply cost of electricity. Innovative technologies allow the decentralized and localized power generation systems to be integrated with renewable energy sources which help to reduce the cost of utility services and provide clean energy. Moreover, technological advancement played a decisive role in enabling the electrical system to be more efficient. Electrical reliability can be improved, greenhouse gas emissions can be reduced, renewable energy sources can efficiently be integrated, and rising demand for electricity can be met by embedding advanced applications and technological equipment in the electrical grid.

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  • 37.
    Bhatti, Harrison John
    et al.
    Halmstad University, School of Business, Innovation and Sustainability. VTI, Swedish National Road and Transport Research Institute, Gothenburg, Sweden.
    Danilovic, Mike
    Halmstad University, School of Business, Innovation and Sustainability. Shanghai Dianji University, Shanghai, China; Lund University, Lund, Sweden.
    Nåbo, Arne
    VTI, Swedish National Road and Transport Research Institute, Gothenburg, Sweden.
    A System Approach to Electrification of Transportation – An International Comparison2022Report (Other academic)
    Abstract [en]

    Globally, the transportation system is transforming from a fossil-based to an electrification system. Some countries are leading in the transformation process. Some countries are rapidly catching up to become market leaders in developing and introducing new techniques and equipment that support the transformation process in their countries. In contrast, others are still relying on their old fossil-based system or could not have enough understanding of how to deal with this complex transformation of the transportation system.

    The electrification of the transportation system is not an isolated system that can be handled as a single technological element. It is a group of multiple technologies, political, societal, and economic sub-systems each of these sub-systems is embedded in each other, forming the whole system. Therefore, it is important to see and manage the system from a holistic perspective to transform the transportation electrification system efficiently. We have selected eight countries from three different continents – Asia (China, India), Australia, which is a country and continent, and Europe (Germany, Norway, Slovenia, Sweden, and the UK) to explore the transformational process of transportation electrification based on each countries’ conditions. We have chosen these continents as they are diversified in adopting transportation electrification system solutions.

    Our main conclusions are that the political processes and political decisiveness are the most important, followed by the societal and economic, with technology as the fourth. The other three are difficult to obtain without dedicated and determined political decision-makers. Political decision-makers need to use economic means to support the transformation in society and industry to balance the economic disadvantage of electric systems until they pass the cost disadvantage turning point. Technology is no longer a significant barrier as it was about 20 years ago. Now, technology is available, although it can be improved. The important part is to understand how to utilize the existing technology efficiently to transform the old fossil-based transportation system into new electrification of the transportation system. Without clear and strong political support, the industry cannot be expected to initiate, finance, take risks, and take the lead in this global societal transformation.

    Our analysis shows that China is being positioned as the leading country in the world in the electrification of the transportation system because of the strong technological advancements, control of the entire value chain, strong government decisiveness, and execution power in developing and implementing favorable electric vehicle (EV) policies, the willingness of the public sector to take the lead and citizens support to adopt clean technology. Norway has rapidly become one of the newcomers with large numbers of registered electric vehicles according to its population size within a few years, despite lacking manufacturing electric vehicles (EVs) and equipment for transportation electrification. Germany is leading in the technological sector of transportation electrification within Europe with its prestigious top-selling electric vehicle brands in Germany, such as Volkswagen, Mercedes Benz, BMW, Smart, and Audi, and establishing a battery Gigafactory with an annual potential production capacity of 60 GWh. However, Germany is still lagging behind from the societal perspective of not having enough sales of electric vehicles compared to gasoline-based vehicles. Sweden is a rapidly growing country in the electrification of transport, with three vehicle manufacturers introducing EVs in 2021 and developing electric roads system for more than ten years. Sweden is also working on establishing a new 50 GWh battery manufacturing plant in Gothenburg, Sweden. The UK is also catching up with its other European countries in transforming the transportation system with its strong government support. The British government has kept transportation electrification on its national agenda and considering building a Gigafactory to obtain a position as a future battery leader. However, the UK's adoption rate of electric vehicles is still slow compared to fossil-based vehicles. India, Australia, and Slovenia are far behind in the process of transportation transformation than China, Norway, Germany, Sweden, and the UK. One of the common reasons in all these countries is their governments' baby steps even though they have high ambitions. Their governments require a revolutionized and systems approach to enable remarkable change in the transformation process.

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  • 38.
    Bhatti, Harrison John
    et al.
    Halmstad University, School of Business, Innovation and Sustainability. VTI, Swedish National Road and Transport Research Institute, Gothenburg, Sweden.
    Danilovic, Mike
    Halmstad University, School of Business, Innovation and Sustainability. Lund University, Lund, Sweden; Shanghai Dianji University, Shanghai, China.
    Nåbo, Arne
    VTI, Swedish National Road and Transport Research Institute, Gothenburg, Sweden.
    Multidimensional Readiness Index for Electrification of Transportation System in China, Norway, and Sweden2022Report (Other academic)
    Abstract [en]

     The main objective of this paper is to develop a readiness index model that can serve as an analytical tool for exploring the achievements of electrification of transportation systems. We have applied this readiness index model to evaluate the readiness positioning of China, Norway, and Sweden towards transport electrification. We have chosen these three countries as they represent diversity among countries that are in the process of adopting electrified transport system solutions. Our developed readiness index model has four key dimensions, technological readiness, political readiness, societal readiness, and economic readiness. The embeddedness of all four dimensions in one model provides a multi-perspective way of analyzing and evaluating the readiness levels of countries moving towards transforming the transportation system. Therefore, we named the model a“multidimensional readiness index.”

    Our main conclusions are that the political processes and political decisiveness involved are the most important factors followed by the societal needs and economic ability, with the current technology available as the fourth. Without the participation of dedicated and determined political decision-makers being involved, the other three factors are challenging to obtain. Political decision-makers need to facilitate the use of economic means to support the transformation in the society and affected industries to balance the initial economic disadvantages of the electrically-powered systems until they pass the cost disadvantage turning point. The development of the relevant technology is no longer a great barrier as it was at the beginning of this transformation, about 20 years ago. The technology for electrically powered transportation systems and devices is widely available now, although it is continuously evolving and being improved. Associated industries cannot be expected to initiate, finance, take the risk, and take the lead in this global societal transformation without clear and strong political support.

    Based on our multidimensional readiness index analysis, China is being positioned as the leading country in the world in the electrification of its transportation systems. This is mainly so because of the strong technology advancements, control of the entire value chain of research, development (R&D), and manufacturing of EVs, strong government decisiveness, and execution power in developing and implementing favorable electric vehicle (EV) policies. The willingness of China’s public sector to take the lead and their citizen’s support to adopt clean technology are additional factors facilitating this advancement. Norway has rapidly become one of the newcomers in electrification with large numbers of registered electric vehicles, despite lacking manufacturing industries of electric vehicles. Sweden is a rapidly developing country in the electrification of transport, with three vehicle manufacturers introducing EVs in 2021. The government has been committed to building demonstration sites for electric roads systems for more than ten years. Sweden is also working on establishing battery manufacturing facilities dedicated to the needs of electrified transportation equipment and systems. 

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  • 39.
    Bjuringer, David
    et al.
    Halmstad University, School of Business, Innovation and Sustainability.
    Sjölander, Alfred
    Halmstad University, School of Business, Innovation and Sustainability.
    Temperaturinverkan på komponenter i vindkraftverk: En förstudie åt Arise AB2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to analyze how different temperature deviations affect the components of wind turbines. A study of the temperatures in several different components was carried out to get a clearer picture of how these affects operational reliability. By trying to link, for example, extreme values of temperatures to possible alarms and downtime in the wind power plants, the hope is that this study will be able to contribute to safer and more maintenance-free wind turbines in the future. The 12 wind turbines that have been evaluated in this study are localized in southern Sweden. The time period for the collected data extends over 6 years.

    In the thesis, an analysis has been carried out with the help of the computer program Matlab to examine different types of data collected from the components in the wind turbines. The data was plotted with the help of various functions in Matlab and with the help of mathematical equations. The data was then observed ocularly by the authors, which led to the discovery of different connections between temperature variations in the components and different error codes. The generator bearing was the component that was found to have the highest correlation between temperature deviations and specific error codes related to various yaw-errors, which can be explained as error codes that occur when the wind turbine fails to adjust itself to the wind.

    An analysis has also been made to determine whether there was a temperature-related upward trend in any of the components in the wind turbines. This was carried out with the help of various standard deviation calculations and calculation of the mean temperature value of different components. The standard deviation in this case describes how much the temperature of each component varies from the mean value. It turned out that there was such an upward trend for the Generator Bearing and Generator Phase 3 components. Some turbines also turned out to have a more distinct upward trend than others

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  • 40. Blom, Elin
    et al.
    Johnsson, Jesper
    Klit, Max
    Energieffektivisering av flerbostadshus: Energieffektiviseringspotentialen undersöks i ett kvarter med flerbostadshus från 1940-talet2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The thesis cover the energy efficiency of a multi-family house from the 1940s situated in Halmstad. As the energy performance in buildings gets better and the energy solutions aregetting smarter, the requirements will be higher for new construction. On the other hand, realestate from the 40's remains the same and are often operated with the same heating systemsas those when originally put into operation.The purpose of the report is to investigate the potential for energy efficiency in olderbuildings as well as the financial consequences of the energy-efficient solutions.The thesis is written on behalf of Halmstad Fastighets AB (HFAB), who intends to evaluatethe neighborhood in 2019 and subsequently decide on the future of the housing area. Thereport is based on this area as a reference and the action proposals presented in the report aresimulated in this housing area. The housing area was commissioned in 1943 and consists offive houses, one longer structure and four point-houses, which makes it the first multiresidentialarea owned and operated by the company. HFAB has an internal target of 75 kWh/m2, year for the entire property stock at the turn of the year 2050, which represents a targetvalue that the report intends to achieve.The report is divided into two parts, the first describing the buildings' current energy systemfrom a theoretical and technical point of view and including an energy survey on existingenergy flows for the properties. The energy survey then constitute the foundation for thesecond part, where theory and technical construction of the systems installed with the actionproposals are described together with reports on the theory for energy saving calculations.The results show that a renovation and investment with modern technology and energyefficient solutions has a major impact on the final energy use, even reaching lower specificvalues than those defined as internal goals within the company. Energy-efficient investmentscan also be a profitable investment from an economic point of view, providing additionalincentives for the property owner.

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  • 41.
    Borgström, Karin Margaretha
    et al.
    Halmstad University, School of Business, Engineering and Science, Centre for Innovation, Entrepreneurship and Learning Research (CIEL), Sustainability, Innovation and Management in Building (SIMB).
    Böhm, Benny
    A comparison of different methods for in-situ determination of heat losses from district heating pipes1996Report (Other academic)
    Abstract [en]

    In the IEA Network Supervision project a special method, the Tx-factor method, is investigated. Several other methods exist for in-situ heat loss determination from district heating (DH) pipes. These methods have advantages and disadvantages compared to the Tx-factor method. It is the purpose of this work to make a comparison of the methods on a particular DH pipe. This makes this investigation special as in most previous work only one or very few methods have been applied on the same DH pipe. The purpose of this work was thus to go out to the site and make measurements of the heat loss from the DH pipe at this particular time of the year - an estimate of annual heat losses could then to be made afterwards. The aim of this work being to develop methods for practical applications not very sophisticated tools were used at the experimental site. This means that although very advanced equipment could have been used for determining the centre line and the depth of the DH pipe only measurement sticks, water levels and strings were used. For the same reasons the temperature sensors were installed by using measurement sticks

  • 42.
    Borja, Álvaro
    Halmstad University, School of Business, Engineering and Science.
    Molten Salt Storage at CHP Plant2017Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Nowadays the main challenge for the energy system is the capability of storing the energy forlater use. To deal with this problem, molten salt storage technology is being used in some solarfacilities. By its implementation, the energy can be stored in the form of heat. However, thefeasibility of this technology is in a testing stage. Its implementation could be done in differentenergy fields. In this thesis, a novel implementation is suggested nearby a CHP, with the aim ofutilizing the excess electricity provided by the grid in high energy production days. Differentimplementation methods and a real scenario are presented. A study analysis of the tank’s sizeand the amount of molten salt needed as well as an economic analysis are provided. Numericalapproximations are given and results shown according to the theoretical analysis developed.

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  • 43.
    Braungardt, Sibylle
    et al.
    The Oeko-Institut, Freiburg, Germany.
    Bürger, Veit
    The Oeko-Institut, Freiburg, Germany.
    Fleiter, Tobias
    The Fraunhofer Institute for Systems and Innovation Research, Karlsruhe, Germany.
    Bagheri, Masha
    The Fraunhofer Institute for Systems and Innovation Research, Karlsruhe, Germany.
    Manz, Pia
    The Fraunhofer Institute for Systems and Innovation Research, Karlsruhe, Germany.
    Billerbeck, Anna
    The Fraunhofer Institute for Systems and Innovation Research, Karlsruhe, Germany.
    Al-Dabbas, Khaled
    The Fraunhofer Institute for Systems and Innovation Research, Karlsruhe, Germany.
    Breitschopf, Barbara
    The Fraunhofer Institute for Systems and Innovation Research, Karlsruhe, Germany.
    Winkler, Jenny
    The Fraunhofer Institute for Systems and Innovation Research, Karlsruhe, Germany.
    Fallahnejad, Mostafa
    Vienna University of Technology, Wien, Austria.
    Harringer, Daniel
    Vienna University of Technology, Wien, Austria.
    Hasani, Jeton
    Vienna University of Technology, Wien, Austria.
    Kök, Ali
    Vienna University of Technology, Wien, Austria.
    Kranzl, Lukas
    Vienna University of Technology, Wien, Austria.
    Mascherbauer, Philipp
    Vienna University of Technology, Wien, Austria.
    Hummel, Marcus
    E-Think, Wien, Austria.
    Müller, Andreas
    E-Think, Wien, Austria.
    Habiger, Jul
    E-Think, Wien, Austria.
    Persson, Urban
    Halmstad University, School of Business, Innovation and Sustainability.
    Sánchez-García, Luis
    Halmstad University, School of Business, Innovation and Sustainability.
    Renewable heating and cooling pathways – Towards full decarbonisation by 2050 – Final report2023Report (Other academic)
    Abstract [en]

    With the adoption of the EU Climate Law in 2021, the EU has set itself a binding target to achieve climate neutrality by 2050 and to reduce greenhouse gas emissions by 55 percent compared to 1990 levels by 2030. To support the increased ambition, the EU Commission adopted proposals for revising the key directives and regulations addressing energy efficiency, renewable energies and greenhouse gas emissions in the Fit for 55 package.

    The heating and cooling (H&C) sector plays a key role for reaching the EU energy and climate targets. H&C accounts for about 50 percent of the final energy consumption in the EU, and the sector is largely based on fossil fuels. In 2021, the share of renewable energies in H&C reached 23%. The decarbonisation of heating and cooling is addressed across several directives and regulations at EU level.

    The aim of this study is to support the analytical basis for the development and implementation of policies to ensure a seamless pathway to the full decarbonisation of the heating and cooling sector by 2050 in buildings and industry.

  • 44.
    Brembilla, Christian
    et al.
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Lacoursiere, Claude
    High Performance Compting Center North (HPC2N), Umeå University, Umeå, Sweden.
    Soleimani-Mohseni, Mohsen
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Olofsson, Thomas
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Investigations of thermal parameters addressed to a building simulation model2015In: Proceedings of BS2015: 14th Conference of International Building Performance Simulation Association, Hyderabad, India, Dec. 7-9, 2015, India, Hyderabad: International Building Performance Simulation Association (IBPSA) , 2015, p. 2741-2748Conference paper (Refereed)
    Abstract [en]

    This paper shows the tolerance of thermal parameters addressed to a building simulation model in relation to the local control of the HVAC system. This work is suitable for a modeler that has to set up a building simulation model. The modeler has to know which parameter needs to be considered carefully and vice-versa which does not need deep investigations. Local differential sensitivity analysis of thermal parameters generates the uncertainty bands for the indoor air. The latter operation is repeated with P, PI and PID local control of the heating system. In conclusion, the local control of a room has a deterministic impact on the tolerance of thermal parameters.

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  • 45.
    Brembilla, Christian
    et al.
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Soleimani-Mohseni, Mohsen
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Olofsson, Thomas
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Hybrid heating system for open-space office/laboratory2015In: Energy, Science and Technology 2015: The energy conference for scientists and researchers. Book of Abstracts, EST, Energy Science Technology, International Conference & Exhibition, 20-22 May 2015, Karlsruhe, Germany / [ed] Karlsruher Institut für Technologie (KIT), Karlsruhe: Karlsruher Institut für Technologie (KIT) , 2015, p. 315-315Conference paper (Refereed)
    Abstract [en]

    Open-space office/laboratory are quite common in Scandinavia and they are usually designed for multipurpose work. There are office area where is possible to work standing up and in the same time to work at the desk. For this purpose a hybrid heating system made by electric convectors and panel radiators is investigated. Two step response tests of the hybrid heating system are performed at the laboratory of Umeå University. The first test is executed during the week, disturbances from heat sources degrading the quality of the results. The second test is performed during week-end. The error analysis shows a maximum discrepancies of +0.6 °C between measured and simulated data. However, a thermal time constant of the room can be deducted and use it for controlling purposes.

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  • 46.
    Brembilla, Christian
    et al.
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Soleimani-Mohseni, Mohsen
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Olofsson, Thomas
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Transient model of a panel radiator2015In: Proceedings of BS2015: 14th Conference of International Building Performance Simulation Association, Hyderabad, India, Dec. 7-9, 2015, India, Hyderabad: International Building Performance Simulation Association (IBPSA) , 2015, p. 2749-2756Conference paper (Refereed)
    Abstract [en]

    This paper shows a transient model of a hydronic panel radiator modelled as a system of multiple storage elements. The experiment´s results suggest the more suitable technique for modelling this technology. The panel radiator is modelled numerically with eight thermal capacitance connected in series by keeping a memory of the heat injected in the thermal unit. The comparison of the performance among lumped steadystate models and transient model, in terms of heat emission and temperature of exhaust flow, shows the potential of the latter approach. To conclude, (1) the transient phase is essential for modelling stocky panels, and (2) this type of modelling has to be addressed for evaluating the performance of low energy buildings.

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  • 47.
    Brembilla, Christian
    et al.
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Soleimani-Mohseni, Mohsen
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Olofsson, Thomas
    Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
    Transient model of a panel radiator2015In: Energy, Science and Technology 2015: The energy conference for scientists and researchers. Book of Abstracts, EST, Energy Science Technology, International Conference & Exhibition, 20-22 May 2015, Karlsruhe, Germany / [ed] Karlsruher Institut für Technologie (KIT), Karlsruhe: Karlsruher Institut für Technologie (KIT) , 2015, p. 321-321Conference paper (Refereed)
    Abstract [en]

    This paper shows a detailed transient model of a panel radiator considered as a system of multiple storage elements. The experiment records the temperature surface of the panel in the process of heating up. The qualitative results of the experiment suggest the more appropriate technique for modelling this technology. The transient model performs the modelling with horizontal thermal capacitances connected in series. This model calculates the temperature of exhaust flow, heat emission towards indoor environment, temperature gradient on panel surface, dead and balancing time identified numerically on the chart.

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  • 48.
    Chee, John
    Halmstad University, School of Business, Engineering and Science.
    Investigations on Energy Efficient Buildings: - the aim to reach zero energy buildings2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The European Parliament Buildings Directive (EPBD) obliges Sweden to develop plans to

    enhance the amount of NZEB. Define what NZEB for them exactly constitutes - technical

    definitions and system boundaries for energy performance calculations. The National Board

    of Housing, Building and Planning in Sweden has received an assignment from the Swedish

    government to propose the definition and quantitative approach on energy requirements for

    NZEB. NBHBP suggest the system boundary should be the delivered (bought) energy. The

    delivered energy divide into two different energy form. The set system boundary to calculate

    the specific energy performance with the introduced weighted factor. Makes it possible to

    compensate the specific energy performance by using renewable energy generators on site.

    The risk is inefficient buildings can use renewable energy technologies on site to compensate

    the delivered energy to achieve the 80 kWh/m2, year (the proposed energy requirements for

    NZEB). This results to high energy cost along with large investments in renewable

    technologies on site, or the need to add fossil fuels to make up the high-energy demand. The

    both reference houses Circuitus and Bright Living are NZEB, per the Swedish definition

    proposal of NZEB from NBHBP. The most significant difference is Circuitus has better heat

    exchanger and building envelope than Bright Living.

    Download full text (pdf)
    fulltext
  • 49.
    Connolly, David
    et al.
    Aalborg University, Aalborg, Denmark.
    Mathiesen, Brian Vad
    Aalborg University, Aalborg, Denmark.
    Østergaard, Poul Alberg
    Aalborg University, Aalborg, Denmark.
    Möller, Bernd
    Aalborg University, Aalborg, Denmark.
    Nielsen, Steffen
    Aalborg University, Aalborg, Denmark.
    Lund, Henrik
    Aalborg University, Aalborg, Denmark.
    Persson, Urban
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Nilsson, Daniel
    Halmstad University, School of Business, Engineering and Science.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Trier, Daniel
    PlanEnergi, Copenhagen, Denmark.
    Heat Roadmap Europe 2050: First Pre-study for the EU272012Report (Other academic)
    Abstract [en]

    This pre-study presents the findings concerning a considerable outlined expansion of the district heating sector within the current EU27 member states until 2050. Heat deliveries are presumed to grow by a factor of 2.1 until 2030 and by a factor of 3.3 until 2050.

    The current energy policy context is that the latest energy communication from the European Commission (Energy Roadmap 2050) contains only a very modest growth in the future for district heating systems and additional industrial heat use from industrial CHP plants. A small increase is foreseen for industrial demands, while heat deliveries to the residential and service sectors are expected to decrease. In total, the heat delivered is expected to increase by less than one per cent per year, giving a total increase of 20% until 2030 and of 40% until 2050.

    In this prestudy, more ambitious growth rates are assessed for district heating in the EU27 between 2010 and 2050. The chosen methodology in this pre-study contains a combination of hour-by-hour energy modelling of the EU27 energy system and mapping of local conditions, which is essential for district heating analysis. However, the link between these two actions has not been fully utilised in this pre-study due to the limited working time available: The mapping action has only indicated the input to the energy modelling action.

  • 50.
    Connolly, David
    et al.
    Aalborg University, Aalborg, Denmark.
    Mathiesen, Brian Vad
    Aalborg University, Aalborg, Denmark.
    Østergaard, Poul Alberg
    Aalborg University, Aalborg, Denmark.
    Möller, Bernd
    Aalborg University, Aalborg, Denmark.
    Nielsen, Steffen
    Aalborg University, Aalborg, Denmark.
    Lund, Henrik
    Aalborg University, Aalborg, Denmark.
    Persson, Urban
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Grözinger, Jan
    Ecofys Germany GmbH, Cologne, Germany.
    Boermans, Thomas
    Ecofys Germany GmbH, Cologne, Germany.
    Bosquet, Michelle
    Ecofys Germany GmbH, Cologne, Germany.
    Trier, Daniel
    PlanEnergi, Copenhagen, Denmark.
    Heat Roadmap Europe 2050: Second Pre-study for the EU272013Report (Other academic)
    Abstract [en]

    Many strategies have already been proposed for the decarbonisation of the EU energy system by the year 2050. These typically focus on the expansion of renewable energy in the electricity sector and subsequently, electrifying both the heat and transport sectors as much as possible. In these strategies, the role of district heating has never been fully explored system, nor have the benefits of district heating been quantified at the EU level. This study combines the mapping of local heat demands and local heat supplies across the EU27. Using this local knowledge, new district heating potentials are identified and then, the EU27 energy system is modelled to investigate the impact of district heating. The results indicate that a combination of heat savings, district heating in urban areas, and individual heat pumps in rural areas will enable the EU27 to reach its greenhouse gas emission targets by 2050, but at a cheaper price than a scenario which focuses primarily on the implementation of heat savings.

123456 1 - 50 of 271
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