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  • 1.
    Andersen, Niklas
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Ismail, Zahir
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Solel från ljudbarriär: längs Annetorpsvägen i Hyllie, Malmö2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    City of Malmö has ambitions for the district Hyllie to become a demonstrative area ofsustainable urban development. As a part of this the following report aims to investigate the potential in using noise barriers combined with photovoltaics along Annetorpsvägen to generate solar electricity. To quantify the losses that shadows from buildings along the roadmight cause, a 3D-model of the area was constructed in SketchUp. This digital model made it possible to simulate shadows and how they change over the year. A reference model of a photovoltaic noise barrier (PVNB) was constructed and used to find the dates on which the solar cells are shadowed depending on building heights and positioning of the barrier.

    The results show that two lengths with a total distance of 400 meters is appropriate for applying photovoltaic noise barriers. Along distance A, a PVNB with a total capacity of 19 kWp is expected to generate 18 000 kWh per year assuming realistic shadowing, which equals 6% losses compared to production without shadows. The PVNB along distance B with installed capacity of 37 kWp has no considerable problems with shadowing and is expected to generate 37 500 kWh per year. This gives a total production of 56 500 kWh per year.

    The combined investment costs (excluding costs for the actual noise barrier) for both power plants are assumed to be approximately one million SEK. Expected economical outcome is a negative capital value after 25 years, although a change of critical factors such as investment aid, investment cost, electricity prices and cost of capital may result in a more positive outcome. Production losses from shadowing and dirt seem to have a minimal effect on the outcome

    Despite uncertainty in the economical outcome, realizing the project would have several other positive effects such as reduction of carbon dioxide emissions and a positive impact on the public view of renewable energy.

  • 2.
    Andersson, Gustav
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Ericsson, Emil
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Dark Ages Interferometer (DALI) Deployment Rover: Energy System2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The cosmic “Dark Ages” is the cosmic era between the epochs of recombination of cosmic microwave background and the formation of the first stars. The only signal from this epoch is from neutral hydrogen, which could represent one of the richest data sets in cosmology. In order to extract this data, NASA/JPL has proposed a rover mission to the farside of the moon to deploy several radio arrays. Here the arrays would gather data undisturbed by human interference. This thesis examines the possibility of using photovoltaic and electric batteries as an energy solution for a rover on the moon. The requirement for such a system to survive on the moon is discussed in a literature study. A proof of concept simulation using a Simulink model has also been done. The thesis concludes that a rover can deploy the radio array using solar energy. It would be able to hibernate through the night using radioisotope heating. It would need to wait for its batteries to charge before each night.

  • 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. Andreasson, Mats
    et al.
    Werner, Sven
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Borgström, Margaretha
    Halmstad University, School of Business and Engineering (SET), Centre for Innovation, Entrepreneurship and Learning Research (CIEL), Sustainability, Innovation and Management in Building (SIMB).
    Värmeanvändning i flerbostadshus och lokaler2009Report (Other academic)
    Abstract [en]

    Multi­family houses and service sector premises constitute 80 % of the customer stock in the Swedish district heating systems. The level of future heat use in these buildings will then have a strong influence on the future district heating economy and the cor­ responding investment demand. As a foundation for a planned study of future heat use, we have per­formed an extensive study of the current heat use for large buildings in Sweden. The input information for this study was the anonymous answers to the an­ nual enquiry of energy use in multi­family houses and service sector premises regarding 2006. Answers were available from 11253 buildings having 77.6 million square meters of residential areas and premises. By using scale factors, estimations could be made for the whole country having 310 million square meters of multi­family houses and premi­ ses. Hence, the enquiry sample constituted a large share of the whole building stock.The specific heat use was analysed by distribution, degree­days, construction year, ventila­tion system, performed conservation measures, and co­operation with other heat supply. A separate study was performed concerning high and low heat use buildings. The use of cold for cooling and water were also analysed.The results show that the individual variations are much larger than the systematic explana­tions for the parameters analysed. Just above 10% of the building spaces were high users of heat (above 200 kWh/m2). The average difference between Northern and Southern Sweden was small, implying a small climatic impact in heat use. The time period between 1965 and 1974 containing the national million dwelling program did not show dramatically higher heat use in the construction year analysis. Installed heat recovery in the ventilation gave a reduction in heat use with 11 kWh/m2 for multi­family houses. This small difference im­plies that the recovery efficiencies were only in average 20­30%. However, the heat recov­ery in service sector buildings was in average more efficient: About 50% in recovery effi­ciency. The conclusion from the conservation analysis is that the measures performed dur­ing the 10 years were done by late­comers rather than by early adopters, since the heat uses after measures in general correspond to the average level for all buildings. Out of 34000 heat pumps installed in the buil­ dings, about half of them were installed in buildings con­nected to district heating.But when more the one heat supply exists, district heat supply dominates, especially in multi­family houses.Typical users with high demands were buildings in the Västmanland and Norrbot­ ten coun­ties, fuel users, certain co­use with electricity, municipal premises, and small buildings. Typical users with low demands were buildings in the Halland county, heat pumps (but due to the systematic error of just accounting for the electricity supply to the heat pumps), state­owned buildings, and large buildings.The district heating companies can help their customers by identification of them as users with high, normal or low demands. This can be accomplished by adding infor­ mation about building space surfaces in the customer files. The heat use above the level 150 kWh/m2 was only 13 % for the multi­family houses and 14 % for the premises. Complete elimination of high use of district heat would then only give a limited, but significant reduction of the total district heat supply.

    Our 6 major conclusions from the project became: • Individual variations dominate compared to systematic causes considering heatuse in multi­family and service sector buildings. • Some systematic causes were identified. • A demand exists for more local measurements of electricity used for heating, thevolume of water use for hot water. • The district heating companies can help their customers to identify them as high,medium or low users of heat. • On short term, a significant potential exists for lower heat use in the Swedishmulti­family and service sector buildings. • More efficient heat use in building will probably be the most important competi­tor to district heat supply in the future.

  • 5.
    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 %.

  • 6.
    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.

  • 7.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Hansson, Anna
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Karlsson, Niklas
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Werner, Sven
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Mattsson, Marie
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Ecology and Environmental Science.
    Klimatgaser i Halland – en målinriktad analys med framtidsperspektiv2014Report (Other academic)
    Abstract [sv]

    Rapporten innehåller en analys av utsläppen av de sex klimatgaserna i Halland mellan 1990 och 2011, en skattning vad som kommer att genomföras till 2020 och förslag till åtgärder för att kunna leverera utsläppsreduktioner efter 2020. Resultaten visar att de halländska utsläppen har minskat med 20 procent sedan 1990, målet om 27 procent lägre utsläpp till 2020 kommer troligen att uppnås, transporter och jordbruk måste kunna leverera utsläppsreduktioner efter 2020, regionala plan- och styrdokument måste i större utsträckning kunna kvantifiera framtida utsläppsreduktioner samt att det behövs ett regionalt kompetenscenter i Halland för att länet ska kunna leverera utsläppsreduktioner i framtiden.

  • 8.
    Averfalk, Helge
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Ingvarsson, Paul
    ÅF, Division Industry, Stockholm, Sweden.
    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), Energiteknik.
    On the use of surplus electricity in district heating systems2014In: Proceedings from the 14th International Symposium on District Heating and Cooling: September, 6-10, 2014: Stockholm, Sweden / [ed] Anna Land, Stockholm: Swedish District Heating Association , 2014, p. 469-474Conference paper (Refereed)
    Abstract [en]

    Maintained balance between supply and demand is a fundamental prerequisite for proper operation of electric power grids. For this end, power systems rely on accessibility to various balancing technologies and solutions by which fluctuations in supply and demand can be promptly met. In this paper, balancing approaches in the case of surplus electricity supply, due to long-term, seasonal, or short-term causes, are discussed on the basis mainly of compiled experiences from the Swedish national power grid. In Sweden, a structural long-term electricity surplus was created in the 1980s when several new nuclear plants were commissioned and built. One of four explicit domestic power-to-heat solutions initiated to maximize the utilization of this surplus electricity, as export capacities were limited, was the introduction of large scale electric boilers and compressor heat pumps in district heating systems. In retrospective, this solution not only satisfied the primary objective by providing additional electricity demand to balance the power grid, but represents today – from an energy systems perspective – a contemporary example of increased system flexibility by the attainment of higher integration levels between power and heat sectors. As European power supply will be reshaped to include higher proportions of fluctuating supply technologies (e.g. wind and solar), causing occasional but recurring short-term electricity surpluses, the unique Swedish experiences may provide valuable input in the development of rational responses to future balancing challenges. The main conclusions from this study are that district heating systems can add additional balancing capabilities to power systems, if equipped with electrical heat supply technologies, hereby contributing to higher energy system flexibility. Consequently, district heating systems also have a discrete but key role in the continued integration of renewable intermittent power supply technologies in the future European energy system.

  • 9.
    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.

  • 10.
    Connolly, David
    et al.
    Aalborg University, Aalborg, Denmark.
    Lund, Henrik
    Aalborg University, Aalborg, Denmark.
    Mathiesen, Brian Vad
    Aalborg University, Aalborg, Denmark.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Möller, Bernd
    Aalborg University, Aalborg, Denmark.
    Persson, Urban
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Boermans, Thomas
    Ecofys, Köln, Germany.
    Trier, Daniel
    PlanEnergi, Copenhagen, Denmark.
    Østergaard, Poul Alberg
    Aalborg University, Aalborg, Denmark.
    Nielsen, Steffen
    Aalborg University, Aalborg, Denmark.
    Heat Roadmap Europe: Combining district heating with heat savings to decarbonise the EU energy system2014In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 65, p. 475-489Article in journal (Refereed)
    Abstract [en]

    Six different strategies have recently been proposed for the European Union (EU) energy system in the European Commission’s report, Energy Roadmap 2050. The objective for these strategies is to identify how the EU can reach its target of an 80% reduction in annual greenhouse gas emissions in 2050 compared to 1990 levels. None of these scenarios involve the large-scale implementation of district heating, but instead they focus on the electrification of the heating sector (primarily using heat pumps) and/or the large-scale implementation of electricity and heat savings. In this paper, the potential for district heating in the EU between now and 2050 is identified, based on extensive and detailed mapping of the EU heat demand and various supply options. Subsequently, a new ‘district heating plus heat savings’ scenario is technically and economically assessed from an energy systems perspective. The results indicate that with district heating, the EU energy system will be able to achieve the same reductions in primary energy supply and carbon dioxide emissions as the existing alternatives proposed. However, with district heating, these goals can be achieved at a lower cost, with heating and cooling costs reduced by approximately 15%. © 2013 Elsevier Ltd.

  • 11.
    Connolly, David
    et al.
    Department of Development and Planning Aalborg University, Aalborg, Denmark.
    Lund, Henrik
    Department of Development and Planning Aalborg University, Aalborg, Denmark.
    Vad Mathiesen, Brian
    Department of Development and Planning Aalborg University, Aalborg, Denmark.
    Möller, Bernd
    Department of Development and Planning Aalborg University, Aalborg, Denmark.
    Østergaard, Poul Alberg
    Department of Development and Planning Aalborg University, Aalborg, Denmark.
    Nielsen, Steffen
    Department of Development and Planning Aalborg University, Aalborg, Denmark.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Persson, Urban
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Trier, Daniel
    PlanEnergi, Copenhagen, Denmark.
    The role of district heating in decarbonising the EU energy system and a comparison with existing strategies2013In: Book of Abstracts: 8th Conference on Sustainable Development of Energy, Water and Environment Systems, 2013Conference paper (Refereed)
    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 emissions targets by 2050, but at a cheaper price than a scenario which focuses primarily on the implementation of heat savings.

  • 12.
    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.

  • 13.
    D'Ambrosio, Marco
    et al.
    Halmstad University, School of Business and Engineering (SET). Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Medaglia, Marco
    Halmstad University, School of Business and Engineering (SET). Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Vertical Axis Wind Turbines: History, Technology and Applications2010Independent thesis Advanced level (degree of Master (Two Years)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In  this  Master Thesis  a  review  of  different  type  of  vertical  axis  wind turbines (VAWT)  and  a preliminary investigation of a new kind of VAWT are presented.

    After an introduction about the historical background of wind power, the report deals with a more accurate analysis of the main type of VAWT, showing their characteristics and their operations. The aerodynamics of the wind turbines and a review of different type on generators that can be used to connect the wind mill to the electricity grid are reported as well.

    Several statistics are also presented, in order to explain how the importance of the wind energy has grown  up  during  the  last  decades  and  also  to  show  that  this development  of  the  market  of  wind power  creates  new  opportunity  also  for VAWT,  that  are  less  used  than  the  horizontal  axis  wind turbine (HAWT).

    In the end of 2009 a new kind of vertical axis wind turbine, a giromill 3 blades type, has been built in Falkenberg, by the Swedish company VerticalWind. The tower of this wind turbine is made by wood,  in  order  to  get  a  cheaper  and  more environment  friendly  structure,  and  a  direct  driven synchronous multipole with permanent magnents generator is located at its bottom. This 200 kW VAWT represents the intermediate step between the 12 kW prototype, built in collaboration with the Uppsala University, and the common Swedish commercial size of 2 MW, which is the goal of the company.

    A  preliminary  investigation  of  the  characteristics  of  this  VAWT  has  been done, focusing  in particular on the value of the frequency of resonance of the tower, an important value that must be never reached during the operative phase in order to avoid serious damage to all the structure, and on the power curve, used to evaluate the coefficient of power (Cp) of the turbine. The results of this investigation and  the steps  followed  to  get  them  are  reported.  Moreover  a  energy production analysis of the turbine has been done using WindPro, as well as a comparison with and older type on commercial VAWT.

  • 14.
    Druyts, Jan
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Control induction motor by frequency converter: Simulation electric vehicle2010Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Summary

     Today we are probably on a point of change for the car industry. The last century was the century of vehicles with internal combustion engines. Fossil fuels were relative cheap, easy accessible and they have a high specific energy. The pollution and dependency on oil caused the last decade an increasing demand for alternatives. Alternatives for electric power plants and for car drives. Yet the turnover to hybrids is a fact and much research is done for pure electric vehicles. Research about the control of electric motors is by that become a hot topic.

    To simulate an electric vehicle drive with an induction motor, a frequency converter is needed. This combination of motor and converter led to many possible experiments. With a few experiments already done and a broad theoretical background report this thesis provides a good bundle of information to start with further experiments. The experiments can become even broader when a flywheel is added as mass inertia momentum and a DC source on the DC-link. Both elements contribute for a better simulation of an electric motor in an electric vehicle.

    What is described in this theoretical report about the combination of an induction motor and converter is only the tip of the iceberg. I had too less time to begin experimenting with the flying wheel. The DC-link voltage becomes ca. 540V. From the perspective of safety I could never work alone with the DC-link. Even with a companion it was too dangerous because the equipment of the Halmstad University is not made for such dangerous voltages. That’s why this thesis contains more theoretical background and less actual practical data.

  • 15.
    Egeskog, Andrea
    et al.
    Chalmers University of Technology, Göteborg, Sweden.
    Hansson, Julia
    Chalmers University of Technology, Göteborg, Sweden.
    Berndes, Göran
    Chalmers University of Technology, Göteborg, Sweden.
    Werner, Sven
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Co-generation of biofuels for transportation and heat for district heating systems: An assessment of the national possibilities in the EU2009In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 37, no 12, p. 5260-5272Article in journal (Refereed)
    Abstract [en]

    Biomass gasification with subsequent synthesis to liquid or gaseous biofuels generates heat possible to use in district heating (DH) systems. The purpose here is to estimate the heat sink capacity of DH systems in the individual EU nations and assess the possibilities for biomass-gasification-based co-generation of synthetic biofuels for transportation and heat (CBH) for DH systems in the EU countries. The possibilities are assessed (i) assuming different levels of competiveness relative to other heat supply options of CBH corresponding to the EU target for renewable energy for transportation for 2020 and (ii) assuming that the potential expansion of the DH systems by 2020 is met with CBH. In general, the size of the DH heat sinks represented by the existing national aggregated DH systems can accommodate CBH at a scale that is significant compared to the 2020 renewable transportation target. The possibilities for CBH also depend on its cost-competitiveness compared to, e.g., fossil-fuel-based CHP. The possible expansion of the DH systems by 2020 represents an important opportunity for CBH and is also influenced by the potential increase in the use of other heat supply options, such as, industrial waste heat, waste incineration, and CHP. © 2009 Elsevier Ltd. All rights reserved.

  • 16.
    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.

  • 17.
    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)
  • 18.
    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.

  • 19.
    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.

  • 20.
    Gadd, Henrik
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Werner, Sven
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Daily Heat Load Variation in Swedish District Heating Systems2010In: 12th International Symposium on District Heating and Cooling, Tallinn, Estonia: Tallinn University of Technology , 2010, p. 199-201Conference paper (Refereed)
    Abstract [en]

    If daily heat load variations could be eliminated in district heating-systems, it would make the operation of the district heating system less costly and more competitive . There would be several advantages in the operation such as:

    • Less use of expensive peak load power where often expensive fuels are used.
    • Less need for peak load power capacity.
    • Easier to optimize the operation that leads to higher conversion efficiencies.
    • Less need for maintenance because of more smooth operation of the plants

    There are a number of ways to handle the daily variations of the heat load. Two often used are large heat storages or using the district heating network as temporary storage. If it would be possible to centrally control the customer substations, it would also be possible to use heavy buildings connected to the district heating system as heat storages.

    To be able to find the best way to reduce or even eliminate the daily heat load variations, you need to understand the characteristics of the daily variations. This paper will describe a way of characterizing daily heat load variations in some Swedish district heating-systems.

  • 21.
    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.

  • 22.
    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.

  • 23.
    Gong, Mei
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    New system solution for biomass CHP plant2019Report (Other academic)
    Abstract [en]

    The main propose with this pre-study was to assess a new Chinese conceptconcerning Combined Heat and Power (CHP) plants for typical Swedish conditionswith biomass as fuel. The new enhancement is to use a large absorption heat pumpfor the final heat supply instead of the turbine condenser. More heat can then berecovered from the three units that will deliver the heat (the flue gas condenser, theturbine condenser and the absorption heat pump). So far, this new CHP solution hasnever been implemented outside China.For this pre-study, the simulation model was elaborated on design data from theÖrtofta biomass CHP plant outside Lund. The results show that Chinese conceptwill provide the higher conversion efficiency, but with lower power-to-heat ratio.The main benefit is that more heat can be recycled from the flue gas condenser. Thepayback time of installing absorption heat pump is always over eight years withinexpected intervals for alternative costs for electricity and heat.The Chinese concept is less suitable for the Swedish context with biomass backpressureCHP plants, since the proportion of lost electricity becomes rather high.The Chinese context with utilization of existing condensation turbines is stillinteresting, since condenser heat can be recycled without major modification ofexisting turbines.

  • 24.
    Gong, Mei
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Wall, Göran
    Öxbo gård, Härryda, Sweden.
    Life Cycle Exergy Analysis of Solar Energy Systems2014In: Journal of Fundamentals of Renewable Energy and Applications, ISSN 2090-4533, E-ISSN 2090-4541, Vol. 5, no 1, article id 1000146Article in journal (Refereed)
    Abstract [en]

    Exergy concepts and exergy based methods are applied to energy systems to evaluate their level of sustainability. Life Cycle Exergy Analysis (LCEA) is a method that combines LCA with exergy, and it is applied to solar energy systems. It offers an excellent visualization of the exergy flows involved over the complete life cycle of a product or service. The energy and exergy used in production, operation and destruction must be paid back during life time in order to besustainable. The exergy of the material that is being engaged by the system will turn up as a product and available for recycling in the destruction stage. LCEA shows that solar thermal plants have much longer exergy payback time than energy payback time, 15.4 and 3.5 years respectively. Energy based analysis may lead to false assumptions in the evaluation of the sustainability of renewable energy systems. This concludes that LCEA is an effective tool for the design and evaluation of solar energy systems in order to be more sustainable.

  • 25.
    Gong, Mei
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Wall, Göran
    Chalmers University of Technology, Gothenburg, Sweden.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Energy and Exergy Analysis of District Heating Systems2012In: 13th International Symposium on District Heating and Cooling: 3rd of September – 4th of September: Copenhagen, Denmark, 2012, p. 55-60Conference paper (Refereed)
    Abstract [en]

    The concept of exergy is defined and applied to district heating systems. The influence from different reference state conditions and system boundaries are explained in some detail. The aim is to show the simplicity and value of using the concept of exergy when analyzing district heating processes. The exergy factor is introduced and applied for a number of Swedish and Danish district heating systems. This varies from 14.2% to 22.5% for Swedish district heating systems. The higher the exergy factor, the more the exergy losses in the passive conversion towards space heating. Large losses revealed in an exergy treatment of a process should be seen as a challenge to achieve technical improvements of the system.

  • 26.
    Gong, Mei
    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), Energy Science.
    An assessment of district heating research in China2015In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 84, p. 97-105Article in journal (Refereed)
    Abstract [en]

    The recent growth of the Chinese district heating sector has been very high. No other country in the world can show the same growth rate during the last decades. The heated building area increased six times between 1995 and 2008. China has also enjoyed strong growth of scientific articles and papers about district heating in recent years. One third of all international scientific journal articles and conference papers about district heating came from Chinese scientists during 2010–2012, while Swedish scientists accounted for one quarter according to the Scopus scientific search engine. It is important to identify the Chinese district heating research to judge the potential for future collaborative research on district heating systems between Sweden/Europe and China. The 205 international publications on district heating by Chinese scientists published until 2013 have been mapped and summarised with respect to demand, supply, technology, market and environment. More diversified heat supply with renewable source was grasping the Chinese interest, since many new systems have been established, having more degrees of freedom when choosing various heat supply and technology options. The Chinese district heating systems were compared with sustainable district heating solutions in Sweden. Both countries would benefit from future research cooperation. © 2015 Elsevier Ltd.

  • 27.
    Gong, Mei
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. 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, Biological and Environmental Systems (BLESS), Energiteknik. Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Enhanced Biomass CHP plants for district heating systems2019Conference paper (Refereed)
    Abstract [en]

    In Sweden, located in North Europa, more than half of the total heat demand in buildings is met by district heating, but only just above one-third of the heat supply comes from Combined Heat and Power. In this paper, a new enhancement of biomass CHP plant is explored. The modification is that a large absorption heat pump is used for the heat supply to the district heating network. This new solution has so far never been implemented outside China. The benefits will be more electricity from lower condenser pressure and more heat obtained from flue gas condensation. The drawback is that the absorption heat pump will require extracted steam that will decrease electricity generation. In order to estimate the offset between the two benefits and the drawback, a simplified model has been developed to study a typical Swedish biomass CHP plant located in Lund. This enhancement could be part of the transition from third generation district heating (3GDH) to fourth generation district heating system (4GDH) by introducing efficient heat supply plants in current systems with high distribution temperatures. Several cases studied concerning both 3GDH and 4GDH have been compared to reference cases. The results show that the enhancement is a possible way to prepare for future 4GDH. Further investigations are recommended concerning pre-investment in absorption heat pumps as a transition strategy for new CHP plants originally designed for return temperatures of 20-30 ºC.

  • 28.
    Gong, Mei
    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), Energy Science.
    Exergy analysis of network temperature levels in Swedish and Danish district heating systems2015In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 84, p. 106-113Article in journal (Refereed)
    Abstract [en]

    Exergy concept is applied on district heating systems with different network temperature levels in their distribution networks. These district heating systems use a combination of renewables and heat recovery from other primary processes. The aim is to show simplicity and value of using exergy concept when comparing current and future temperature levels. Both the traditional exergy factor and the novel exergy utilisation rate are used in these analyses. Exergy utilisation rate expresses the ratio between the exergy delivered to customer heating systems and the exergy content in heat supply input to the distribution network. The analyses are performed on four different generations of district heating technologies, two national groups of district heating systems in Denmark and Sweden for revealing variations among systems, and two municipal systems for revealing variations within systems. The main conclusions are simplifications can be introduced in order to analyse the network temperature levels, current exergy factors reveal that current temperature levels can be reduced, and that almost two thirds of the exergy content in heat supply input are lost in the heat distribution chain. These conclusion will be vital input in developing the future fourth generation of district heating systems using both renewables and heat recovery. © 2015 Elsevier Ltd.

  • 29.
    Gong, Mei
    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.
    Mapping Energy and Exergy Flows of District Heating in Sweden2016In: Proceedings the 15th International Symposium on District Heating and Cooling: September 4th - 7th, 2016, Seoul, South Korea / [ed] Rolf Ulseth & Kyung Min Kim, 2016, p. 96-102Conference paper (Refereed)
    Abstract [en]

    District heating has been available in Sweden since the 1950s and used more than half of the total energy use in dwelling and no-residential premises in 2013. Energy and exergy efficient conversion and energy resources are key factors to reduce the environmental impact. It is important to understand energy and exergy flows from both the supply and demand sides. The exergy method is also a useful tool for exploring the goal of more efficient energy-resource use. Sankey diagrams together with energy and exergy analyses are presented to help policy/decision makers and others to better understand energy and exergy flows from primary energy resource to end use. The results show the most efficient heating method in current district heating systems, and the use of renewable energy resources in Sweden. It is exergy inefficient to use fossil fuels to generate low quality heat. However, renewable energies, such as geothermal and solar heating with relative low quality, make it more exergy efficient. Currently, about 90% of the energy sources in the Swedish district heating sector have an origin from non-fossil fuels. Combined heat and power is an efficient simultaneous generator of electricity and heat as well as heat pump with considering electricity production. Higher temperature distribution networks give more distribution losses, especially in exergy content. An outlook for future efficient district heating systems is also presented.

  • 30.
    Gong, Mei
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Werner, Sven
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    On district heating and cooling research in China2014In: Proceedings from the 14th International Symposium on District Heating and Cooling: September, 6-10, 2014: Stockholm, Sweden, Stockholm: Swedish District Heating Association , 2014, p. 325-332Conference paper (Refereed)
    Abstract [en]

    The growth of the Chinese district heating sector has been very rapid during recent years. No other country in the world can show the same rapid growth of district heating systems during the last decades. Heated building area increased six times between 1995 and 2008 according to the Chinese district heating statistics. China has also enjoyed strong growth of scientific articles and papers published about district heating in recent years. During 2010-2012, one third of all international scientific journal articles and conference papers about district heating came from Chinese scientists, while Swedish researchers accounted for one quarter. It is important to identify the Chinese district heating and cooling research to judge the potential for future collaborative research on district heating systems between Sweden/Europe and China. Until 2013, Chinese district heating and cooling scientists have published 205 international publications on district heating and 36 publications on district cooling. In this paper, these articles are mapped and summarised with respect to topics, active research institutions, and their technology focuses. Another approach is to grasp the Chinese interest for more diversified heat supply, since many new systems are established and thereby have more degrees of freedom when choosing by various heat supply and technology options.

  • 31.
    Graneskog, Axel
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Gustafsson, Yngve
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Smart Control: En reaktion på EU:s ekodesignkrav2012Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to assist the Swedish energy company NIBE Energy Systems in their studies of adaptive regulation applicable to electrical water heaters. Due to coming energy classifications of these appliances in the European Union, NIBE Energy Systems needs to use adaptive regulation, called Smart Control, to keep their products in the best possible energy class and remain competitive to the market. By using this Smart Control regulation a 2-3 % improve-ment of efficiency can be credited the system. This is a small number, but heavily needed, since the energy classes are based on the idea that the European Union is provided with electricity from coal condensate power resulting in a 40 % maximum efficiency. Furthermore, doing noth-ing will result in some water heaters not being approved to use on the market from 2015 due to low efficiency. The thesis is made out of three sections; product-/literature studies of products already commercially available using similar principles, data analysis on existing Smart Controlled water heater and recommendations to the company for future development of their own system. Limitations have been made through simplified calculations and thermodynamic assumptions. A conclusion can still be made from the thesis; electrical water heaters using Smart Control saves 10 - 15 % of electrical energy use today in a real world environment. Main sources to this thesis have been data analysis, Internet, brochures and conversations with the mentors.

  • 32.
    Gunnarsson, Martin
    et al.
    Halmstad University. Halmstad University, School of Business and Engineering (SET). Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Johannesson, Rickard
    Halmstad University. Halmstad University, School of Business and Engineering (SET). Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Waste Management with Focus on Waste incineration with energyrecovery in Chisinau Municipality, Moldova2010Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The amount of waste in the world increases every year due to an improved living standard andgrowing population. The problem is especially large in poor countries where the ability tohandle the waste is limited due to financial and management problems. If instead wastematerial is seen as a resource it can help reduce the amount of waste on landfill. Byincinerating waste and recover the energy it would also help reducing greenhouse gasemissions from landfill and give electric and thermal energy.Chisinau Municipality in the Republic of Moldova today lacks several important parts fora satisfying waste management. Today most of the waste generated in Chisinau municipalityends up at the municipality landfill. The current contract to use the landfill expires on the 31December 2010, if the municipality won’t be able to renew the contract they have to look forother ways to deal with the waste problem. As the dominating source for energy in Chisinau isimported natural gas, an effective way to reduce the use of gas for electricity and thermalenergy production would be to use waste material for incineration with energy recovery.Therefore, the goal with this thesis is to evaluate the possibility to extract energy from coincinerationof sewage sludge and waste material generated in Chisinau. To reach this goal thesituation in Chisinau where studied on site for two months, quantities and composition of thewaste material was investigated. Based on the data gathered on the waste, a suitabletechnology for the waste-to-energy (WTE) plant is proposed. The proposal is made based onthe assumption that a WTE plant would not be established until 2025.The result shows that the waste material in Chisinau can be used for co-incineration ofwaste and sludge. The calorific value of the waste material was determined to 7.87 MJ per kg.The suggested WTE plant has the total power of 138 MW, the result based on that all wastematerial available 2025 are incinerated. Annually this makes it possible to recover 1152 TJ(320 GWh) electric power and 2650 TJ (736 GWh) heat, based on 8000 operating hoursannually.Even if a WTE plant sounds like a good investment it is a long time before a plant couldoperational. Much is to be made in the waste management to have well-functioninginfrastructure that will work together with an incineration plant. Furthermore, the data used inthis study regarding the quantities is very uncertain and further studies in affected areas arenecessary before a WTE plant can be established.

  • 33.
    Hammar, Mikael
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Huszág, Máté
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Geotermi i Ungern: Undersökning av Ungerns energisituation inriktat på geotermi samt kapacitetsfaktorn för det största geotermiska värmeverket i Mellaneuropa.2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Hungary’s share of renewable energy in 2010 was 7.9 %, and their renewable energy goal for 2020 is 14.65 %. Geothermal energy is one option that could help to achieve the goal, since Hungary has favorable bedrock, the temperature gradient is above average and thepermeability is high. Today Hungary is importing just over half of its primary energy supply. Because of political conflicts between nations Hungary wants to expand its own production of energy. One of the major investments implemented was to build the largest geothermal heating plant in central Europe, located in Miskolc. This degree theses aims is to raise the capacity factor for this heating plant. To achieve this objective, a survey of how grain dryers and absorption chillers could increase the heat load in the summer has been performed. With grain dryers that only dries wheat, the capacity factor for the geothermal heating plant in Miskolc increased by 2.6 % and by 4.4 % for the absorption chiller. Although surveys have been carried out for a specific case the idea can be implemented in other heating plants.

    Keywords: Capacity factor, geothermal energy, wheat dryers and absorptions chiller.

  • 34.
    Houtkamp, Christofer
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Spillvärmeåtervinning2012Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    SAPA´s resource of waste heat is the basis for this thesis to investigate the possibility of energy assets in their cooling water and possible uses for it. The energy in the waste water is greater than the current need which has three uses which are (1) heating the factory, (2) converting liquid propane to propane gas and (3) local domestic heating. The average energy load that is available is 1, 7 MW and the average temperature in the cooling water is 41°C. The total energy load at dimensioning out side temperature is approximately 1,6 MW for the three current uses. The temperature is currently too low to be used directly in the existing systems so an upgrade is needed. The district heating has the highest temperature requirements at 100°C in the winter. To reach the relatively high temperatures required a hybrid heat pump proves to be a suitable solution due to a good Coefficient of Performance (COP). The disadvantage is that at the moment hybrid heat pumps have to be tailor made and are therefore very expensive. The investment required to extract the most amount of surplus energy is large due to the expensive tailor made hybrid heat pumps and the high cost of laying underground heat transferring pipes which leads to long pay off times as the value of surplus heat from waste water is low.

  • 35.
    Hurtig, Jörgen
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Report-evaluation of a small scale district heating system in Ullared, Sweden2010Report (Other (popular science, discussion, etc.))
    Abstract [en]

    This evaluation and final report is a part of an EU-project, “Energy in Minds” (EiM). The project is a part of the EU-programme Concerto within the Sixth Framework Programme. EiM has been running from 2005 and is now finalized in May 2010. Within the EiM project, the local energy company, Falkenberg Energi AB (FEAB), has received EU-funding of totally 98 200 Euro for the two local heating systems consist of a completely new small scale district heating system in Ullared and one partly new in Vessigebro, in the north-east part of the municipality of Falkenberg. The system in Ullared, which this report is focusing on, a prefabricated transportable heating plant with a boiler of 1500 kW has been installed. The fuel used is pellets. The pipe network consists now of about 2,5 km of double pipeline. 22 customers have been con-nected so far, representing a heat demand of about 2400 MWh annually. The main customers are the school building, health care centre, elderly housing and the parish. The main pipe network is made up of traditional double district heating pipes of steel with polyurethane insulation and a polythene casing.

    The financial results have improved during 2009, mostly due to greatly reduced depreciations. For 2009 the result was +304 000 SEK. (2008: -146 000 SEK) The heat density of the system in Ullared is, being a small scale district heating system, quite normal with a linear heat density of about 0,8 MWh/m. But the key problem of the district heating system in Ullared is the very low connection rate which is roughly estimated to 22%. This is for the system in Ullared at the same time a well needed future potential for expansion. The Environmental impact is important for many customers when they chose their heating system and it is usually a good argument for the district heating industry as a whole. However, the environmental impact from low density district heating systems is higher than for traditional systems since both heat losses and resource depletion from pipes and components increase with lower heat density. Still research report referred to in this report states that the choice of district heating is a good choice for the environmental impact for those property owners who today uses fossil fuel for heating. One estimation says roughly a reduction of 40 tons of CO2-equivalents per year compared with oil furnace heating. Finally, the small scale district heating system in Ullared has definitely the potential of attracting more customers in the future with a well spread out distribution net with many buildings close situated offering an alternative for change of heating system for potential customers for a future connection when energy prices for oil and electricity increases even more. Anyway it will have a positive impact on the environment both globally and locally.

  • 36.
    Hurtig, Jörgen
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Report-evaluation of multi-storey Low Energy Houses at Hertings Gård, Falkenberg2010Report (Other (popular science, discussion, etc.))
    Abstract [en]

    The new residential buildings at Hertings Gård in Falkenberg are built and owned by the local municipal housing company, Falkenbergs Bostads AB (FaBo) during 2007-2010. It is a good example of when knowledge of Passive house technology combined with good energy planning and project management can result in multi-storey houses with energy rating under 50kWh/m2. The multi-storey houses at Hertings Gård have innovative solar air heating systems connected to the ventilation system that is quiet unique. The solar air heating system contributes to the buildings energy supply by preheating the ventilation supply air. (The solar air is part of another project in Energy in Minds). This evaluation is based on metered energy used for space heat, domestic hot water, electricity for building service and domestic electricity for two of the multi-storey houses during 2009, House 18 and 19. The result is presented as monthly uses and compared with initial project specifications and some other parameters. The total initial energy specifications set by Concerto/Energy in Minds and FaBo for the houses are almost reached. Results are for House 18 and 19, 76,8 and 77,5 kWh/m2. (Specification 75 kWh/m2) This is total use of purchased energy. (excl. lighting at parking lots, not corrected after Swedish statistical normal year.) If we exclude the domestic energy use, the results looks as follows, House 18 47,8 and House 19 45,9 kWh/m2.(Specification: 50 kWh/m2). The used domestic energy for 2009 is varying a lot (House 18 from about 650 kWh up to 6500 kWh) between the apartments and is in total roughly 20% more than was expected in the project. A conclusion is that domestic energy is most of all a result of the tenant’s individual needs and behavior. Another energy specification that is not fully reached is the electricity for building service which is slightly more than specified in the project. The efficiency of the ventilation system is analyzed (with Specific Fan Power, SFP=2,80) which is relatively high compared to recommendations in National Swedish building code. This is probably a consequence of the chosen ventilation system with functions such as individual indoor temperature control. This function needs a design of the ventilation system that causes more power drops and therefore also more power than a more traditional and centralized ventilation system. The energy used for domestic hot water (DHW) is about 26% lower than specified in the project. (14,75 kWh/m2, year vs 20 kWh/ m2, year). The metered average specific DHW use at Hertings Gård is 0,27 m3/m2 and year. This is just slightly over the average of about 128 000 German apartments with individual metering and charging of DHW (0,25 m3/m2 and year). Hertings Gård has individual metering and charging of DHW use and low-flush water taps which are contributing to this relatively low DHW use. What is also achieved at Hertings Gård is, at least when looking at the tenant’s answers in the completed survey, that it seems to be a valued housing for its comfort as well as in other quality aspects. Many tenants can recommend the housing to other people. In conclusion, Hertings Gård is a good housing for the tenants, most probably a good investment for the housing company and above all a good living for the environment and the climate.

  • 37.
    Ivarsson, Johanna
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Solceller för flerbostadshus: En teknisk rapport för HFAB2011Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    This examination paper is about the potential for Solar cells on apartment blocks. The technology with using solar cells for manufacturing electricity, has been on the market for a while, but recently the new installations of solar cells has increased. Solar cells are suited for placements on buildings but are expensive to obtain. The municipal real-estate company is interested in solar cells but wants to know more before they invest in the technology. This report contains an account of the solar cell and a guide to how a connection to the grid is accomplished. The report even contains suggestions of where the solar cells can be located and an estimate of annual production of electricity on a building. The outcome of the report is that there are good prerequisites for solar cells on apartment blocks and it shows the real- estate company as an environmental-thinking corporation.

  • 38.
    Jönsson, Linnea
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Sänkt returtemperatur: Potentiell besparing i fjärrvärmesystem2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Optimizing energy systems is, in Sweden, as in many other countries, of growing interest. District heating systems are no exception. In 2012, 285 out of 290 municipals in Sweden had district heating in use and the majority of these systems have a higher return temperature than that which is possible with an error-free substation of day current technology. To, when possible, lower the return temperature is a way of increasing the effectiveness of the district heating system.This study means to investigate, through simulations and calculations, how big of a reduction in production cost a lower temperature in the city of Ystad’s district heating system would correspond to. The results show that a cold year, such as 2010, 1.8 SEK of the production cost could be saved per MWh sold heat for a whole year and 1°C temperature lowering. Equivalent value for a warm year such as 2011 was concluded to be 1.2 SEK/MWh,°C.

  • 39.
    Kalén, Jonas
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Åkerlund, Nathan
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Gårdsbaserad biogas på Nya Skottorp: utvärdering och optimering av anläggningen och uppgradering av biogasen2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Biogas is an expanding sector within the broad field of agriculture and animal production. Small-scale biogas offers local combined power and heating production and the substrate is transformed into high-quality biological fertilizer. This bachelor thesis focuses on a pig farm in south-western Sweden, where biogas is produced from pig manure, evaluates and suggests ways of optimizing the process and investigates whether investing in an upgrading plant would be a feasible and more cost-efficient option. The results show that the biogas plant is working well, although the production differs from the original plans. This shows in turn that planning and examining the basic conditions before making the investment is of great importance, as well as monitoring and keeping detailed statistics of the running process. Logistical factors make optimizing the process through additional substrates difficult. The thesis shows that investing in a Biosling upgrading plant would be a profitable option, supposing that the upgraded gas is sold via the natural gas infrastructure. Furthermore, many farmers are interested in producing their own fuel for tractors and other machines, which offers more future alternatives for the upgraded biogas. However, biogas producers in Sweden today are not offered any particular subsidies, which makes it especially hard for small-scale producers.

  • 40.
    Kjällquist, Mattias
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Närvärmeanläggningar: Teknisk underlagsrapport och sammanställning av driftserfarenheter2011Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
  • 41.
    Larsson, Sebastian
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS), Energiteknik.
    Bulleremissioner från vertikalaxlade vindkraftverk2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wind power in Sweden is expanding in response to the government's decision that 49% of Sweden's power should originate from renewable energy sources by the year 2020. Problems with noise and sound emissions related to wind turbines are a constant argument against the wind power expansion and this paper means to examine if vertical axis wind turbines might be a viable alternative to the conventional horizontal design for noise sensitive areas. In order to determine factors like difference in frequency, noise propagation and noise emission level, measurements of both horizontal and vertical axis wind turbines have been completed and the data analyzed with MATLAB. It is shown that there is a difference in how the noise from the two types of turbines propagates due to avariation in the frequency spectra of the emitted sound. It is also shown that vertical axis wind turbines generate a lower sound emission with less intensity inthe lower frequencies.

  • 42.
    Lund, Henrik
    et al.
    Ålborgs universitet, Ålborg, Danmark.
    Werner, Sven
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Wiltshire, Robin
    Building Research Establishment, Watford, UK.
    Svendsen, Svend
    Danmarks Tekniska Universitet - DTU, Lyngby, Danmark.
    Thorsen, Jan Eric
    Danfoss, Nordborg, Danmark.
    Hvelplund, Frede
    Ålborgs Universitet, Ålborg, Danmark.
    Vad Mathiesen, Brian
    Ålborgs universitet, Köpenhamn, Danmark.
    4th Generation District Heating (4GDH): Integrating smart thermal grids into future sustainable energy systems2014In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 68, p. 1-11Article in journal (Refereed)
    Abstract [en]

    This paper defines the concept of 4th Generation District Heating (4GDH) including the relations to District Cooling and the concepts of smart energy and smart thermal grids. The motive is to identify the future challenges of reaching a future renewable non-fossil heat supply as part of the implementation of overall sustainable energy systems. The basic assumption is that district heating and cooling has an important role to play in future sustainable energy systems – including 100 percent renewable energy systems – but the present generation of district heating and cooling technologies will have to be developed further into a new generation in order to play such a role. Unlike the first three generations, the development of 4GDH involves meeting the challenge of more energy efficient buildings as well as being an integrated part of the operation of smart energy systems, i.e. integrated smart electricity, gas and thermal grids. © 2014 Elsevier Ltd.

  • 43.
    Möllerström, Erik
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Vertical Axis Wind Turbines: Tower Dynamics and Noise2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Vertical axis wind turbines (VAWTs) have with time been outrivaled by the today common and economically feasible horizontal axis wind turbines (HAWTs). However, VAWTs have several advantages such as the possibility to put the drive train at ground level, lower noise emissions and better scaling behavior which still make them interesting for research.

    The work within this thesis is made in collaboration between the Department of Construction and Energy Engineering at Halmstad University and the Division for Electricity at Uppsala University. A 200 kW VAWT owned by the latter and situated close to Falkenberg in the southwest of Sweden has been the main subject of the research even if most learnings has been generalized to fit a typical vertical turbine. This particular turbine has a wooden tower which is semi-guy-wired, i.e. the tower is both firmly attached to the ground and supported by guy-wires.

    This thesis has two main topics both regarding VAWTs: eigenfrequency of the tower and the noise generated from the turbine. The eigenfrequency of a semi-guy-wired tower is studied and an analytical expression describing this is produced and verified by experiments and simulations. The eigenfrequency of the wire itself and how it is affected by wind load are also studied.  The noise characteristics of VAWTs have been investigated, both theoretically and by noise measurement campaigns. Both noise emission and frequency distribution of VAWTs has been studied.

    The work has resulted in analytical expressions for tower and wire eigenfrequency of a semi-guy-wired tower as well as recommendations for designing future towers for VAWTs. The noise emission of VAWTs has been studied and proven low compared to HAWTs. The noise frequency distribution of the 200 kW VAWT differs significantly from that of a similar size HAWTs with for example lower levels for frequencies below 3000 Hz.

  • 44.
    Möllerström, Erik
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. Division for Electricity, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Bolin, Karl
    Marcus Wallenberg Laboratory, Department of Aeronautical and Vehicle Engineering, KTH Royal Institute of Technology, Stockholm, Sweden.
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Bååth, L.B.
    Halmstad University, School of Business, Engineering and Science, Mechanical Engineering and Industrial Design (MTEK).
    Hylander, Jonny
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Noise directivity from a vertical axis wind turbine2015In: Proceedings of the 6th International Conference on Wind Turbine Noise 2015, New Brighton: INCE/Europe , 2015Conference paper (Other academic)
    Abstract [en]

    The directivity of wind turbine noise is of widespread interest and has received attention over an extended period. The reason for this is partly that noise optimization procedures can be implemented in order to increase the efficiency of the power output. Although directivity of horizontal axis wind turbines (HAWTs) are well understood, the directivity pattern around vertical axis wind turbines (VAWTs) are less well investigated.This paper presents measurements of directivity on a 200 kW VAWT, a so called H-rotor, with variable speed and a tower height of 40 m. The turbine, which is situated in a flat agricultural landscape close to Falkenberg at the Swedish west coast, is one of the world’s largest today operational VAWTs. Experimental results as well as a theoretical model based on the turbulent-boundary-layer trailing-edge (TBL-TE) noise suggest higher noise levels upwind of the rotor and the lowest noise levels in the perpendicular directions. Moreover, modulation analysis of the measurements indicates the presence of modulations but the results are inconclusive.

  • 45.
    Möllerström, Erik
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. Uppsala University, Uppsala, Sweden.
    Eriksson, Sandra
    Uppsala University, Uppsala, Sweden.
    Goude, Anders
    Uppsala University, Uppsala, Sweden.
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Hylander, Jonny
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Turbulence influence on optimum tip speed ratio for a 200 kW vertical axis wind turbine2016In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 753, article id 032048Article in journal (Refereed)
    Abstract [en]

    The influence of turbulence intensity (TI) on the tip speed ratio for maximum power coefficient, here called λCp-max, is studied for a 200 kW VAWT H-rotor using logged data from a 14 month period with the H-rotor operating in wind speeds up to 9 m/s. The TI - λCp-max relation is examined by dividing 10 min mean values in different turbulence intensity ranges and producing multiple CP(λ) curves. A clear positive relation between TI and λCp-max is shown and is further strengthened as possible secondary effects are examined and deemed non-essential. The established relation makes it possible to tune the control strategy to enhance the total efficiency of the turbine.

  • 46.
    Möllerström, Erik
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. Uppsala University, Uppsala, Sweden.
    Larsson, Sebastian
    Halmstad University, School of Business and Engineering (SET).
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Hylander, Jonny
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Bååth, Lars
    Halmstad University, School of Business, Engineering and Science, Mechanical Engineering and Industrial Design (MTEK).
    Noise Propagation from a Vertical Axis Wind Turbine2014In: Proceedings of 43rd International Congress on Noise Control Engineering: Internoise 2014 / [ed] John Davy, Charles Don, Terry McMinn, Liz Dowsett, Norm Broner & Marion Burgess, Brisbane, QLD: Australian Acoustical Society , 2014Conference paper (Refereed)
    Abstract [en]

    Initial noise measurements were performed on a 200kW vertical axis wind turbine (VAWT) and results were compared to that of a Vestas V27, a similar size horizontal axis wind turbine (HAWT). Multiple recording units were placed in line downwind of the turbine to investigate noise propagation. The frequency distribution of the noise were analyzed indicating that the VAWT has lower relative levels for frequencies under 3000 Hz, especially within 600-1200 Hz. Furthermore, VAWT noise seems to occur more around the same frequencies as the natural background noise, increasing masking probability. Results from propagation measurements seemed to indicate that noise declines more rapidly with distance for the VAWT then for the reference HAWT, possibly explained by the lower levels at low frequencies. Further investigation is needed to establish these differences and the 200 kW VAWT creates an opportunity doing so utilizing arguably the largest operational VAWT existing today.

  • 47.
    Möllerström, Erik
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. Uppsala University, Uppsala, Sweden.
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Goude, Anders
    Uppsala University, Uppsala, Sweden.
    Eriksson, Sandra
    Uppsala University, Uppsala, Sweden.
    Hylander, Jonny
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Bernhoff, Hans
    Uppsala University, Uppsala, Sweden.
    Turbulence influence on wind energy extraction for a medium size vertical axis wind turbine2016In: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 19, no 11, p. 1963-1973Article in journal (Refereed)
    Abstract [en]

    The relation between power performance and turbulence intensity for a VAWT H-rotor is studied using logged data from a 14 month (discontinuous) period with the H-rotor operating in wind speeds up to 9 m/s. The turbine, designed originally for a nominal power of 200 kW, operated during this period mostly in a restricted mode due to mechanical concerns, reaching power levels up to about 80 kW. Two different approaches are used for presenting results, one that can be compared to power curves consistent with the International Electrotechnical Commission (IEC) standard and one that allows isolating the effect of turbulence from the cubic variation of power with wind speed. Accounting for this effect, the turbine still shows slightly higher efficiency at higher turbulence, proposing that the H-rotor is well suited for wind sites with turbulent winds. The operational data are also used to create a Cp(λ) curve, showing slightly lower Cp compared with a curve simulated by a double multiple streamtube model. Copyright © 2016 John Wiley & Sons, Ltd.

  • 48.
    Möllerström, Erik
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. Division for Electricity, Department of Engineering Sciences, Uppsala University, PO Box 534, SE - 751 21 Uppsala, SwedenDivision for Electricity, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Hylander, Jonny
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Bernhoff, Hans
    Division for Electricity, Department of Engineering Sciences, Uppsala University, PO Box 534, SE - 751 21 Uppsala, SwedenDivision for Electricity, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden.
    Avoidance of resonances in a semi-guy-wired vertical axis wind turbine2014Conference paper (Refereed)
    Abstract [en]

    Resonance analysis for a vertical axis wind turbine is performed. The turbine may be described as semi-guy wired, being bolted stiffly to the ground as well as supported by guy wires. The influence of the first mode eigen frequency of the guy wires and how it is affected by wind load is examined. Using beam theory, an analytical model for calculating the first mode eigen frequency of the guy wire for different wind loads is derived. The analytical model is verified with FEM-simulations and then used to assemble a diagram showing how to combine the wire size, inclination angle and pre-tension for an eigen frequency range over the 3P load for nominal rotational speed and for a certain effective spring force acting on the tower. This diagram, here called an EA-T diagram, may be used as a quick tool for comparing wire setups and a similar diagram can be used for other guy wired structures.

  • 49.
    Möllerström, Erik
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Hylander, Jonny
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Bernhoff, Hans
    Uppsala Universitet.
    Eigen Frequencies of A Vertical Axis Wind Turbine Tower Made of Laminated Wood and the Effect Upon Attaching Guy Wires2014In: Wind Engineering: The International Journal of Wind Power, ISSN 0309-524X, E-ISSN 2048-402X, Vol. 38, no 3, p. 277-290Article in journal (Refereed)
    Abstract [en]

    Eigen frequencies of a vertical axis wind turbine tower made out of laminated wood which are both bolted to the ground and supported by guy wires are studied and compared. Using beam theory, an analytical model taking the guy wires into account for calculating the first mode eigen frequency of the tower has been derived. The analytical model is then evaluated by comparing with FEM-simulations and measurements performed on the actual tower. The model is found to be reasonably accurate keeping in mind that the estimated masses and second moments of area are somewhat rough. Furthermore the model can be used to give an indication of the magnitude of change in eigen frequency when modifying a tower or guy wire property.

  • 50.
    Möllerström, Erik
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik. Uppsala University, Uppsala, Sweden.
    Ottermo, Fredric
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Hylander, Jonny
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Energiteknik.
    Bernhoff, Hans
    Uppsala University, Uppsala, Sweden.
    Noise Emission of a 200 kW Vertical Axis Wind Turbine2016In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 9, no 1, article id 19Article in journal (Refereed)
    Abstract [en]

    The noise emission from a vertical axis wind turbine (VAWT) has been investigated. A noisemeasurement campaign on a 200 kW straight-bladed VAWT has been conducted, and the result hasbeen compared to a semi-empirical model for turbulent-boundary-layer trailing edge (TBL-TE) noise.The noise emission from the wind turbine was measured, at wind speed 8 m/s, 10 m above ground, to96.2 dBA. At this wind speed, the turbine was stalling as it was run at a tip speed lower than optimaldue to constructional constraints. The noise emission at a wind speed of 6 m/s, 10 m above groundwas measured while operating at optimum tip speed and was found to be 94.1 dBA. A comparisonwith similar size horizontal axis wind turbines (HAWTs) indicates a noise emission at the absolutebottom of the range. Furthermore, it is clear from the analysis that the turbulent-boundary-layertrailing-edge noise, as modeled here, is much lower than the measured levels, which suggests thatother mechanisms are likely to be important, such as inflow turbulence.

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