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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. 

  • 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.

  • 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.

  • 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.

  • 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. 

  • 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.

  • 7.
    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 %.

  • 8. 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.

  • 9.
    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.

  • 10.
    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.

  • 11.
    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

  • 12.
    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, ISSN 1996-1073, 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.

  • 13.
    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.

  • 14.
    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.

  • 15.
    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, E-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

  • 16.
    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)
  • 17.
    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.

  • 18.
    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)
  • 19. 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
  • 20.
    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.

  • 21.
    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

  • 22.
    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. 

  • 23.
    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
  • 24.
    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
  • 25.
    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.

  • 26. 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.

  • 27.
    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.

  • 28.
    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.

  • 29.
    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.

  • 30.
    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.

  • 31.
    Dalla Rosa, Alessandro
    et al.
    Technical University of Denmark, Lyngby, Denmark.
    Li, Hongwei
    Technical University of Denmark, Lyngby, Denmark.
    Svendsen, Svend
    Technical University of Denmark, Lyngby, Denmark.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Persson, Urban
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Rühling, Karin
    Dresden University of Technology, Dresden, Germany.
    Felsmann, Clemens
    Dresden University of Technology, Dresden, Germany.
    Crane, Martin
    Scottish & Southern Energy, Perthshire, United Kingdom.
    Burzynski, Robert
    Scottish & Southern Energy, Perthshire, United Kingdom.
    Bevilacqua, Ciro
    Building Research Establishment, Watford, United Kingdom.
    Annex X Final report: Toward 4th Generation District Heating: Experience and Potential of Low-Temperature District Heating2014Report (Other academic)
    Abstract [en]

    Background and Objective

    The evolution of district heating (DH) has gone through three generations since the first introduction of distirct heating. It is characterized by the type of transport media and the network temperature levels: the 1st generation DH system is steam-based system, the 2nd generation DH uses high network supply temperature above 100oC, and the 3rd generation DH represents the current DH system with medium network supply temperature between 80oC to 100oC. Up until now, the 4th generation DH as the low-temperature district heating (LTDH) is emerging as a new system which is going to replace the existing 3rd generation DH system. Comparing with the existing DH system, the LTDH reduces the network supply temperature down to consumer required temperature level, thus greatly improves the quality match between the energy supply and the energy demand. Meanwhile, LTDH coupling with reduced network temperature and well-designed DH network can reduce network heat loss by up to 75% comparing with the current system. This makes DH economically competitive comparing with local heat generation units in the areas with low heat density or with low-energy buildings.

    The traditional approach to evaluating a DH system often focuses on the production/supply aspect and only afterwards on the final users. The LTDH concept switches the perspective, starting from end-user thermal comfort and a quality match between energy supply and energy consumption, and aiming to find the best and most economical way to satisfy the heat demand through efficient distribution networks and supply systems based on waste heat and RE. The new concept therefore starts by identifying suitable in-house substations for low-energy-demand buildings at low supply temperature, goes back to design efficient and reliable networks, and finally considers environmentally-friendly heat production units.

    This report describes the concept of LTDH, collects and discusses successful examples of implementation LTDH in the building heating sector. The objective of this report is to raise awareness and provide insights that will stimulate the research, development and implementation of LTDH systems. It will help to increase public recognition and assist policy makers and energy planners, both at local and governmental level, in promoting cost-effective and environmentally friendly DH systems, and in planning and realizing long-term sustainable urban area development. To this end, the report addresses the following research issues:

    1. What are the main advantages of LTDH?

    2. What technology options are available for LTDH, and what are the associated challenges to consider?

    3. How can the risk of Legionella be mitigated in LTDH?

    4. What lessons can be learned from early LTDH projects?

    5. What heat distribution costs are associated with LTDH?

  • 32.
    David, Andrei
    et al.
    Aalborg Univ, Dept Planning, Copenhagen, Denmark.
    Vad Mathiesen, Brian
    Aalborg Univ, Dept Planning, Copenhagen, Denmark.
    Averfalk, Helge
    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).
    Lund, Henrik
    Aalborg Univ, Dept Planning, Aalborg, Denmark.
    Heat Roadmap Europe: Large-Scale Electric Heat Pumps in District Heating Systems2017In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 10, no 4, article id 578Article in journal (Refereed)
    Abstract [en]

    The Heat Roadmap Europe (HRE) studies estimated a potential increase of the district heating (DH) share to 50% of the entire heat demand by 2050, with approximately 25–30% of it being supplied using large-scale electric heat pumps. This study builds on this potential and aims to document that such developments can begin now with technologies currently available. We present a database and the status of the technology and its ability of expansion to other European locations by reviewing experiences aimed at further research or application in the heating industry. This is based on a survey of the existing capacity of electric large-scale heat pumps with more than 1 MW thermal output, operating in European DH systems. The survey is the first database of its kind containing the technical characteristics of these heat pumps, and provides the basis for the analysis of this paper. By quantifying the heat sources, refrigerants, efficiency and types of operation of 149 units with 1580 MW of thermal output, the study further uses this data to analyze if the deployment of this technology on a large-scale is possible in other locations in Europe. It finally demonstrates that the technical level of the existing heat pumps is mature enough to make them suitable for replication in other locations in Europe.

  • 33.
    Deutschmann, Oliver
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Johansson, Thomas
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Framtidens elbilar utmanar nutidens elnät: Påverkan av ett ökat antal elbilar på ett halländskt elnät2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The challenges facing low voltage grids are rising as an increasing number of domestic houses transition from fossil fueled heating to electricity based heating. Several environmental goals and visions have the same transition from fossil based power to electricity based power in mind for the transportation sector. One of the most important tools for this transformation is widely regarded to be the electric vehicle. With the demands of the electric vehicle pressuring the power grid, several questions arise regarding the growth of the electric vehicle market and what repercussions it may have on the grid. This paper focuses on a typical low voltage grid in southern Sweden and what effects a growing electric vehicle market may have on it. Through computer-assisted simulations based on several future scenarios regarding the EV market, this paper finds that few modifications and reinforcements are needed on this particular grid within the next 10 to 15 years. After this timeframe the voltage drop becomes a serious concern and should be addressed.

  • 34.
    Dia, Ali
    et al.
    Halmstad University, School of Business and Engineering (SET).
    Bengtsson, Fredrik
    Halmstad University, School of Business and Engineering (SET).
    Energikartläggning av lagerbyggnad: en kvalitativ studie mot lagerbyggnader inom logistik branschen2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 35.
    Engdahl, Annelie
    Halmstad University, School of Business, Engineering and Science.
    How grid connected solar cells impact on the low voltage grid of Duckarp2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To limit the ongoing climate change and to meet the UN target for an increased temperature of maximum 2 degrees, governments worldwide strive for sustainable and fossil free power generation. Hence, Photovoltaic Solar Cells (PVs) are of great interest. The potential from sun is infinite; the annual solar radiation corresponds to 6.000 times the human energy demand (IEA, 2011).

    In Sweden, the power generation from sun is 0.6 ‰ (Swedenergy, 2016). It is a very small, but strongly growing, share. In the municipality of Kristianstad, south of Sweden, the vision of power generation from sun is clear: by 2040, 5 % of the electricity consumption in the area is to come from PVs (Kristianstad kommun, 2016). Along with an increased interest from subscribers, more grid connected PVs are to be expected.

    An increased share of grid-connected PVs, influences the power grid. The power quality must comply with legal requirements and maintain a certain voltage. This might be a problem in rural power grids where the distances are far; the grid is getting weaker and the voltage deviation grows. Never the less, the law requires the concession holder to compensate the subscriber in relation to the decreased losses in the grid. With power generation closer to the subscriber, the distances are shorter and the grid losses is decreased.

    Mellersta Skånes Kraft (MSK) is a power distribution company located in Scania, south of Sweden. In the feeding 6 kV grid, a major part of the conductors are over-head lines, meaning a lot of interruptions caused by stormy weather and fallen trees. Hence, MSK is planning for isolated conductors to decrease the number of interruptions. 

    At present, MSK have a few, sporadically placed, grid connected PVs and the power generation of today, regarding power quality, is not a problem. However, MSK sees an increased interest in PVs and more power generation the next few years are to be expected. The question is, how several grid-connected PVs will impact the power grid.

    In this dissertation, the rural low voltage grid of Duckarp, Kristianstad municipality, has been studied. The grid is connected to the very last transformer in a radial grid. Two cases have been modulated: one with existing PVs of today, and one with PVs at all subscribers connected to the transformer T-640, Duckarp. As the feeding 6 kV grid is to be rebuilt, the study included the choice of cable cross section area in the 6 kV grid as well. The study included grid strength, voltage deviation, load in cables and transformer, and grid losses including compensation to subscriber.  

    The study shows, that with present PVs and with the condition that a tap changing transformer is used, the grid is strong and capable of keeping the voltage required. Due to voltage deviation, more grid connected PVs make the grid weaker and require higher cable cross section areas on the feeding 6 kV grid. The load is not a problem, but still there is a risk of a high proportion of harmonics in the neutral and in the transformer. This, due to the low voltage grid being located in the weakest part of the grid. The reduced losses, due to local power generation, corresponds to a compensation to subscriber of 0.02 SEK/kWh.

    Building strong power grids is expensive and alternative solutions, so-called smart grids, are of interest; Line Voltage Regulator (LVR), reactive power generation in the inverter, battery storage, or load regulations to mention some. But when there is an ongoing reconstruction of the grid, as in the case studied, it is appropriate to build a strong power grid to meet a future expansion of grid-connected PVs.

  • 36.
    Ericsson, Karin
    et al.
    Environmental and Energy Systems Studies, Department of Technology and Society, Lund University, Lund, Sweden.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    The introduction and expansion of biomass use in Swedish district heating systems2016In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 94, p. 57-65Article in journal (Refereed)
    Abstract [en]

    District heating satisfies about 60% of the heat demand in Swedish buildings. Today, more than two thirds of the heat supply to the district heating systems is based on biomass and waste, and biomass alone accounts for about half of the heat supply. The purpose of this paper is to present the Swedish experiences of introducing and expanding the use of biomass in the district heating systems and to identify the main drivers behind this development. Our five research questions and the corresponding conclusions consider the driving forces from energy policy tools and local initiatives, the biomass prices, the established infrastructures in forestry and district heating, the technology paths for biomass conversion, and finally the future challenge of competing uses of biomass. © 2016 The Authors

  • 37.
    Eriksson, Fredrik
    et al.
    Halmstad University, School of Business and Engineering (SET).
    Karlsson, Martin
    Halmstad University, School of Business and Engineering (SET).
    Framås, Kjell Ivar
    Halmstad University, School of Business and Engineering (SET).
    Sekundärnät för lågtempererad fjärrvärme2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Lower energy use in buildings is a result of increasingly stringent energy requirements across Europe. When conventional district heating technology is used in areas with low energy consumption heatlosses do not fall even though the amount of energy delivered is reduced. This reduces income for thedistrict heating company. To maintain their economic viability the district heating companies’ majorchallenge is to implement new solutions that minimize heat loss. This report aims to provide the district heating company Eidsiva Bioenergi AS an example of thepossibilities and limitations of a secondary low temperature district heating system. Focus areas arepast and present limitations of plastic pipes and on what temperatures may be used when taking intoconsideration the potential for growth of Legionella bacteria in hot water systems.The report's goal is to present a theoretical design of a low temperature secondary network for districtheating located in Lillehammer, Norway. The report is written in collaboration with the Norwegiancompany Eidsiva Bioenergi AS.The given solution consists in a secondary low temperature district heating system built with plasticpipes supplying four apartment buildings of a total of 360 student apartments. The network shouldmaintain a supply temperature of 60 °C and a return temperature of 30 °C.A secondary network means lower pressure and temperature levels, making it possible to use plasticpipes. Plastic pipes have an advantage regarding installation as they do not require welding and can besupplied in lengths of 50,100 or 200 meters which can speed up trenching work. The authors are of the opinion that the present plastic piping technology have an adequate technicaldurability and does no longer cause problems with oxygen diffusion if installation is done correctly. Although it was possible to design a secondary low temperature district heating network with lowerheat losses, it was not the most profitable in this case even though heat losses are lower than forconventional technology. Secondary low temperature district heating network with plastic pipes aremore competitive in areas with lower energy demands. We recommend that Eidsiva Bioenergi AS to gain knowledge from this report and look foropportunities to implement the solution in areas where conventional technology is less competitive,such as in new housing developments and more heat sparse areas. The technology can also have great advantages in areas with difficult topography or where longer periods of open trenches are not wanted. In all these cases the fast and flexible installation of plastic pipes can give great financial savings.

  • 38.
    Eriksson, Jacob
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Edelönn, Erik
    Halmstad University, School of Business, Engineering and Science.
    Vision 2045: Ett förnybart Halland2019Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Since the resolution made in Paris during the COP21 conference in 2015, governments have been hard at work implementing new regulations accordingly. Regional authorities in Sweden has been given the task of managing and constructing strategies in the field of energy and environmental policies. This thesis aims at analysing the potential for the county of Halland to become a sustainable and renewable region in the longer term as well as to achieve the objectives of the Swedish government. It does so in cooperation with the representing regional authority, The County Administration Board in Halland, and their work form the basis of method for this paper.

     

    The purpose of this paper has been to indicate, demonstrate and motivate a sustainable change in Halland and to describe what technical possibilities are available of implementation as of today.

     

    Six main chapters constitutes the report and are structured in a way to cover contemporary theory, future opportunities and the author’s assumptions, opinions and suggestions of measures. The technical background and methodology in this paper has mostly consisted of studies of literature from sources within energy technology such as relevant authors, companies, authorities and research institutions.

     

    The results show that by the year 2045, a massive expansion of renewable energy is both theoretically and practically feasible, whilst levels of greenhouse gas emissions can be reduced by more at least two thirds compared to the levels of 2016.

  • 39.
    Eriksson, Robin
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energy Science.
    Heat storages in Swedish district heating systems: An analysis of the installed thermal energy storage capacity2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    District heating is the most common source of heating in Sweden and has played a crucial part in the country’s substantial reductions of carbon dioxide emissions. This recycling technology is ideal in order to use thermal energy as efficiently as possible and makes the goals set for a sustainable future more achievable. The future potential of this technology is therefore huge. Today, a lot of the district heating systems have installed heat storages in order to improve the systems reliability and performance. These heat storages have the potential to be utilized even further in the future by acting as a balancing power for the power grid. However, there is currently no data available regarding the storage capacity available in the district heating systems. This thesis therefore seeks to quantify the installed storage capacity in Swedish district heating systems. The data gathered regarding this can then be utilized in research regarding potential future applications of heat storages, such as balancing the power grid. All collected data regarding heat storage capacity has also been analyzed in an effort to find any correlations between the relative storage capacity and the size, energy sources, customer prices and operational costs of each investigated system. This analysis has concluded that most of the district heating systems in Sweden have installed storage capacity and that it is more commonly used in larger systems. It is also concluded that most of the installed storage capacity is used to counteract daily heat load variations. The heat storages influence district heating systems by reducing their operational costs as well.

  • 40.
    Eriksson, Robin
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Johansson, Alexander
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Energieffektivisering av bostäder: En analys av åtgärder som kan förbättra energiprestandan i flerbostadshus2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Efficient energy use in the housing sector is crucial for achieving a sustainable society. The expansion of this sector only represents a fraction of the existing houses, hence it’s within the existing houses the potential for energy savings lie. This potential has been analyzed in order to determine if it’s possible to cut the current energy demand in half. An ongoing renovation project was used as a reference to evaluate the different measures that can increase a buildings efficiency. The measures evaluated were also compared to similar ones from other projects. The main methods examined were ventilation systems utilizing heat exchangers, energy efficient windows and glazed balconies. Based on cost efficiency and amount of energy saved, the results were then evaluated and compared to one another. This showed that the cost efficiency for the different measures varied depending on the size of the building, meaning the different measures should be prioritized in different scenarios. It was concluded that it’s theoretically possible cut the current energy demand of the housing sector in half, but very hard and costly to achieve in reality.

  • 41.
    Etbaeitabari, Amir
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Barakat, M.
    Univ Denver, Denver, CO USA..
    Imani, A. A.
    Iran Islamic Azad Univ, Babol Branch, Babol Sar, Iran..
    Domairry, G.
    Univ Mazandaran, Dept Mech Engn, Babol Sar, Iran..
    Jalili, P.
    Islamic Azad Univ, Dept Mech Engn, Takestan Branch, Takestan, Iran..
    An analytical heat transfer assessment and modeling in a natural convection between two infinite vertical parallel flat plates2013In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 188, p. 252-257Article in journal (Refereed)
    Abstract [en]

    Heat transfer by natural convection occurs in many physical problems and engineering applications such as geo-thermal systems, heat exchangers, petroleum reservoirs and nuclear waste repositories. These problems and phenomena are modeled by ordinary or partial differential equations. In most cases, experimental solutions cannot be applied to these problems, so these equations should be solved using special techniques. Recently, much attention has been devoted to these methods to construct analytic solutions; such as the perturbation method. Perturbation techniques are dependent upon small parameter. Thus, it is worthwhile developing a new technique independent of small parameter. The Reconstruction of Variational Iteration Method technique is a powerful and convenient algorithm in finding the solutions for the equations. While this method is capable of reducing the size of calculation, it overcomes the difficulty of the perturbation technique or Adomian polynomials by applying Laplace Transform. In this paper an analysis has been performed to study the natural convection of a non-Newtonian fluid between two infinite parallel vertical flat plates and the effects of the non-Newtonian nature of fluid on the heat transfer are studied. In order to compare with exact solution, velocity and temperature profiles are shown graphically. The obtained results are valid with significant accuracy. (C) 2013 Elsevier B.V. All rights reserved.

  • 42.
    Fischer, Viktoria
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Frost, Henrik
    Halmstad University, School of Business, Engineering and Science.
    Solvärme med kombinerad värmelagring i flerbostadshus2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to examine the possibilities to incorporate solar heat and thermal energy storage to a newly produced apartment block with a low energy use. From HFAB we were given the block “Jordmåen” in Halmstad. “Jordmåen” that was complete in 2015, consists of 4 apartment buildings and fills its need of 669 MWh of thermal energy withdistrict heating.

    The thesis describes a theoretical study about solar heat and thermal energy storage. To establish a usable area for the solar panels, measurements of an actual building have been made, given to us by HFAB. We use actual data from the Buildings but with the assumption that the buildings aren’t built. Solar panels from ASV Solar are used in the measurements, and possible energy production has been calculated with the program PVGIS. The economic calculations are based on two methods, Pay-off and value approach.

    “Jordmåen” would be able to cover its heating needs from April to September and provide an addition of thermal energy for the remaining months, with 932 m2 of solar panels connected to a borehole thermal energy storage (BTES) with a degree of efficiency of 65 %. The payoff time for this system varies between 9 to 14 years, and the present worth varies between - 1 027 281 kr and - 22 343 kr, with the best outcome in a scenario with roof integrated solar collectors because of the savings of expensive roof material.

    The conclusion is that solar heat combined with heat storage is not a profitable investment when not using the full capacity of the thermal heat storage. Although some parameters are missing to establish the real profit we advise to do a more in-depth investigation to get a more accurate outcome.

  • 43.
    Forssén, Jens
    et al.
    Chalmers, Div Appl Acoust, Dept Civil & Environm Engn, Gothenburg.
    Schiff, Martin
    Lally Acoust Consulting, New York.
    Pedersen, Eja
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS).
    Persson Waye, Kerstin
    Univ. Gothenburg.
    Wind turbine noise propagation over flat ground: measurements and predictions2010In: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, Vol. 96, no 4, p. 753-760Article in journal (Refereed)
    Abstract [en]

    Noise from wind turbines is of concern in the planning process of new wind farms, and accurate estimations of immission noise levels at residents nearby are required. Sound propagation from wind turbine to receiver could be modelled by a simplified standard model assuming constant meteorological conditions, by an engineering method taking atmospheric and ground propagation conditions into account, or by a more exact model. Epidemiological studies have found a higher frequency of annoyance due to wind turbine noise than to other community noise sources at equal noise levels, indicating that the often used simplified model is not sufficient. This paper evaluates the variation of immission sound levels under the influence of meteorological variation and explores if the prediction of levels could be improved by taking the effect of wind speed on sound propagation into account. Long-term sound recordings and measurements at a distance of 530 m from a wind turbine show that the simplified standard model predicts the average sound pressure levels satisfactorily under downwind conditions, and that a more complex propagation model might not be needed for wind turbine noise at a relatively short distance. Large variations of sound immission levels at the same wind speed were however present. Statistical analysis revealed that these variations were influenced by meteorological parameters, such as temperature, static pressure and deviation from ideal downwind direction. The overall results indicate that meteorological factors influence the noise generated by the wind turbine rather than the sound propagation.

  • 44.
    Frederiksen, Svend
    et al.
    Lund University, Lund, Sweden.
    Werner, Sven
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    District Heating and Cooling2013 (ed. 1)Book (Refereed)
  • 45.
    Fredriksson, Linda
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Johansson, Julia
    Halmstad University, School of Business, Engineering and Science.
    Termisk energilagring2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden is only utilizing half of the available excess heat. To utilize more of the excess heat a seasonal thermal energy storage could be implemented to store excessed heat from the summer when the demand is lower to the winter when the demand is higher. This can be achieved by an integration of a seasonal thermal energy storage to the district heating system. A seasonal thermal energy storage may also reduce the need of the system’s peak load, which often is economically costly and adversely affect the environment. The purpose of the paper is to investigate the possibility for Skövde Värmeverk to implement a seasonal thermal storage. The paper is performed by a literature collection and calculations are made by software programs. The result shows that it is technically possible to implement a pit thermal energy storage and a borhole thermal energy storage, but no outcome shows a profitability within 20 years. A pit thermal energy storage can replace the system’s peak load up to 79 percent and a borhole thermal energy storage up to 2,8 percent. The most suitable case for Skövde Värmeverk is to install a pit thermal energy storage with a storage capacity of 4 GWh.

  • 46.
    Fältström, Mattias
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Ferdinandsson, Mikael
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Förutsättningar för absorptionskyla: Examensarbete på Öresundskraft2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The cooling demand increases in Sweden despite the cold climate, which could cause the increase of district cooling. District cooling is a centralized cooling system with multiple benefits such as safer operations, reduced failures and removal of rumbling that will otherwise occur in local cooling systems. That’s why the absorption chiller is becoming more and more interesting to incorporate indistrict heating.The purpose of this report is to give the company Öresundskraft the technical and economic conditions for absorption cooling in Helsingborg. The main goal with the report have been to investigate: which temperature from the district heating system will be used for the absorptions chiller, how the coefficient of performance affects the conditions of absorption chiller, different dimensions for absorption chiller, different placement options for absorption chiller, if the existing cool water storage tank can be used in the future, is it profitable to invest in an absorption plant. The main goal questions have been answered through interviews, compilation and calculation of data, examination of research literature and other literature. Conclusions the authors were able to find is that the absorption chiller should be sized to 2,2 MW and it should be placed on Västhamnsverket. Under the conditions that there was access to cheap heat and only operating during the summer the result to invest in an absorption plant was profitable.

  • 47.
    Gadd, Henrik
    et al.
    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), Energiteknik.
    Achieving low return temperature from district heating substations2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, p. 59-67Article in journal (Refereed)
    Abstract [en]

    District heating systems contribute with low primary energy supply in the energy system by providing heat from heat assets like combined heat and power, waste incineration, geothermal heat, wood waste, and industrial excess heat. These heat assets would otherwise be wasted or not used. Still, there are several reasons to use these assets as efficiently as possible, i.e., ability to compete, further reduced use of primary energy resources, and less environmental impact. Low supply and return temperatures in the distribution networks are important operational factors for obtaining an efficient district heating system. In order to achieve low return temperatures, customer substations and secondary heating systems must perform without temperature faults. In future fourth generation district heating systems, lower distribution temperatures will be required. To be able to have well-performing substations and customer secondary systems, continuous commissioning will be necessary to be able to detect temperature faults without any delays. It is also of great importance to be able to have quality control of eliminated faults. Automatic meter reading systems, recently introduced into district heating systems, have paved the way for developing new methods to be used in continuous commissioning of substations. This paper presents a novel method using the temperature difference signature for temperature difference fault detection and quality assurance of eliminated faults. Annual hourly datasets from 140 substations have been analysed for temperature difference faults. From these 140 substations, 14 were identified with temperature difference appearing or eliminated during the analysed year. Nine appeared during the year, indicating an annual temperature difference fault frequency of more than 6%. © 2014 The Authors.

  • 48.
    Gadd, Henrik
    et al.
    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).
    Daily heat load variations in Swedish district heating systems2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 106, p. 47-55Article in journal (Refereed)
    Abstract [en]

    Heat load variations in district heating systems are both seasonal and daily. Seasonal variations have mainly its origin from variations in outdoor temperature over the year. The origin of daily variations is mainly induced by social patterns due to customer social behaviours. Heat load variations cause increased costs because of increased peak heat load capacity and expensive peak fuels. Seasonal heat load variations are well-documented and analysed, but analyses of daily heat load variations are scarce. Published analyses are either case studies or models that try to predict daily heat load variations. There is a dearth of suitable assessment methods for more general analyses of existing daily load variations. In this paper, a novel assessment method for describing daily variations is presented. It is applied on district heating systems, but the method is generic and can be applied on every kind of activity where daily variations occur. The method was developed from two basic conditions: independent of system size and no use of external parameters other than of the time series analysed. The method consists of three parameters: the annual relative daily variation that is a benchmarking parameter between systems, the relative daily variation that describes the expected heat storage size to eliminate daily variations, and the relative hourly variation that describes the loading and unloading capacity to and from the heat storage. The assessment method could be used either for design purposes or for evaluation of existing storage. The method has been applied on 20 Swedish district heating systems ranging from small to large systems. The three parameters have been estimated for time series of hourly average heat loads for calendar years. The results show that the hourly heat load additions beyond the daily averages, vary between 3% and 6% of the annual volume of heat supplied to the network. Hereby, the daily variations are smaller than the seasonal variations, since the daily heat load additions, beyond the annual average heat load, are between 17% and 28% of the annual volume of heat supplied to the network. The size of short term heat storage to eliminate the daily heat load variations has been estimated to a heat volume corresponding to about 17% of the average daily heat supplied into the network. This conclusion can also be expressed as an average demand of 2.5 m3 of heat storage volume per TJ of heat supplied by assuming a water temperature difference of 40 C. The capacity for loading and unloading the storage should be equal to about half of the annual average heat load for heat supplied into the network. © 2013 Elsevier Ltd.

  • 49.
    Gadd, Henrik
    et al.
    Oresundskraft AB, S-25106 Helsingborg, Sweden..
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Fault detection in district heating substations2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 157, p. 51-59Article in journal (Refereed)
    Abstract [en]

    Current temperature levels in European district heating networks are still too high with respect to future conditions as customer heat demands decrease and new possible heat source options emerge. A considerable reduction of temperature levels can be accomplished by eliminating current faults in substations and customer heating systems. These faults do not receive proper attention today, because neither substations nor customer heating systems are centrally supervised. The focus of this paper has been to identify these faults by annual series of hourly meter readings obtained from automatic meter reading systems at 135 substations in two Swedish district heating systems. Based on threshold methods, various faults were identified in 74% of the substations. The identified faults were divided into three different fault groups: Unsuitable heat load pattern, low average annual temperature difference, and poor substation control. The most important conclusion from this early study of big data volumes is that automatic meter reading systems can provide proactive fault detection by continuous commissioning of district heating substations in the future. A complete reduction of current faults corresponds to approximately half the required reduction of the current temperature levels in the effort toward future low-temperature district heating networks. (C) 2015 The Authors. Published by Elsevier Ltd.

  • 50.
    Gadd, Henrik
    et al.
    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).
    Heat load patterns in district heating substations2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 108, p. 176-183Article in journal (Refereed)
    Abstract [en]

    Future smart energy grids will require more information exchange between interfaces in the energy system. One interface where dearth of information exists is in district heating substations, being the interfaces between the distribution network and the customer building heating systems. Previously, manual meter readings were collected once or a few times a year. Today, automatic meter readings are available resulting in low cost hourly meter reading data. In a district heating system, errors and deviations in customer substations propagates through the network to the heat supply plants. In order to reduce future customer and heat supplier costs, a demand appears for smart functions identifying errors and deviations in the substations. Hereby, also a research demand appears for defining normal and abnormal heat load patterns in customer substations. The main purpose with this article is to perform an introductory analysis of several high resolution measurements in order to provide valuable information about substations for creating future applications in smart heat grids. One year of hourly heat meter readings from 141 substations in two district heating networks were analysed. The connected customer buildings were classified into five different customer categories and four typical heat load patterns were identified. Two descriptive parameters, annual relative daily variation and annual relative seasonal variation, were defined from each 1 year sequence for identifying normal and abnormal heat load patterns. The three major conclusions are associated both with the method used and the objects analysed. First, normal heat load patterns vary with applied control strategy, season, and customer category. Second, it is possible to identify obvious outliers compared to normal heat loads with the two descriptive parameters used in this initial analysis. Third, the developed method can probably be enhanced by redefining the customer categories by their indoor activities.

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