mdh.sePublikationer
Ändra sökning
Avgränsa sökresultatet
1234567 101 - 150 av 723
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 101.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Environment friendly contribution of the microbes to energy conversion2016Ingår i: Microbiological Industrial Hygiene, Nova Science Publishers, Inc. , 2016, s. 349-359Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    There is enough biomass annual growth to replace all fossil fuels used principally. Still, only a small portion of this is actually used efficiently. In this chapter we discuss the resources and how they can be utilized in different ways. Especially use in bio-refineries is discussed, where both full scale plants and future directions is addressed. Concerning future directions for bio-refineries an EU project ABOWE demonstrated how organic waste can be used for production of chemicals like 2,3-butanediol, valeric acid, hydrogen and other organic acids. After this crops for food is discussed and how waste from agriculture can be utilized as source for production of the chemicals and crops with different metabolic paths are discussed briefly, C3, C4 and CAM crops. C3 crops are the most common while C4 and CAM have more efficient systems for CO2 fixation and also have much higher efficiency from sun to chemicals. Also other applications are presented like extraction of metals using microorganisms and production of meat replacement using fungi. Finally obstacles for the efficient utilization of biomass are discussed. 

  • 102.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    How to develop a sustainable fossil fuel free Stockholm-Malardalen region2010Ingår i: World Renewable Energy Congress XI 25-30 September 2010, Abu Dhabi, UAE / [ed] Ali Sayigh, Abu Dhabi: WREC/WREN , 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    First the energy balance of today is determined in a way that is possible to follow up from year to year. The second phase is to determine what available renewable energy resources we have and how these can be utilised. Hydro power already gives 5 TWh/y in the region, but new resources and enhancements of the existing as different wastes and crops are reviewed. The possibility to use solar power and TPV (Thermo Photo Voltaic) is discussed. Next step is to make a scenario for how to reach a consumption that is less than the available resources, and here different consumption patterns as well as ways to change these are considered. Energy efficient buildings and smart homes can give major impact on one of the major needs as heating is of major importance winter time, and cooling summer time. The pros and cons for different solutions are discussed.

     

  • 103.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    MODELLING AND CONTROL OF A DRY BLACK LIQUOR GASIFICATION PROCESS2006Konferensbidrag (Refereegranskat)
  • 104.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Modelling and design of a dry black liquor gasification process2006Ingår i: Proceedings of IFAC, ALSIS06, Helsinki, 2006, s. 64-69Konferensbidrag (Refereegranskat)
    Abstract [en]

    The purpose of this paper is to present modelling and design of a new type of black liquor gasification process with significant benefits compared to existing Tomlinson boilers and wet gasification processes. The organics are gasified by mainly steam reforming, as the temperature is relatively low (below 850 °C) and the water content of the black liquor relatively high (> 20 % water). The gasification can be with or without direct caustization. Sulphates are reduced to first Na2S, and then most of the sulphur is evaporated as H2S (Hydrogen sulphide), after reaction with CO2 + H 2O.The hydrogen sulphide is absorbed in a and used for preimpregnation of the wood chips, to give modified cooking with stronger and brighter fibres out from the digester. With TiO2 added, sodium carbonate is converted into Na2O.TiO2, which dissolved in water gives 4 NaOH + Na2O.(TiO2)3. The direct caustization makes the lime kiln unnecessary. The gas may be combusted in a gas turbine /steam turbine cycle, to produce 2-3 times more electricity than conventional recovery boilers, that is an electrical efficiency of 30-35.

  • 105.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    PROCEEDINGS FROM SCIENTIFIC CONFERENCE ON GREEN ENERGY AND IT2008Proceedings (redaktörskap) (Övrigt vetenskapligt)
    Abstract [en]

    Scientific session on Energy saving and Green energy

    Chairman: Erik Dahlquist, Mälardalen University

    1. Investigations on CO2 absorption using amine solvents in hollow fiber membrane contactors by experiments .

    Yuexia Lv1, Xinhai Yu1*, Shan-tung Tu1, J. Yan2, E. Dahlquist2,School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China; 2. Dept. IST, Mälardalen University, Västerås, Sweden

    2. Intensification of transesterification for synthesis of biodiesel using microchannel reactors.

    Zhenzhong Wen1, Xinhai Yu1*, Shan-tung Tu1, J. Yan2, E. Dahlquist2 1. School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China; 2. Dept. IST, Mälardalen University, Västerås

    3. Continuous bioethanol production by fermentation

    . Bernt Lie, Juan I. Videla.Telemark University College, Porsgrunn, Norway

    4. Optimization and Economic Analysis of Marnoch Thermal Energy Conversion System,

    C.C. Chukwu1, G.F Naterer2, M.A. Rosen3, E. Dahlquist4 I.A Marnoch5 ,1,2,3,4 University of Ontario Institute of Technology, Oshawa. Ontario, Canada, 4 Malardalen University, Vasteras Sweden, 5 Marnoch Thermal Power Inc. Toronto, Ontario, Canada,

    5. Analysis of the coal based polygeneration system of hybrid type

    Guoqiang Zhang1,2, Lin GAO1, Hongguang JIN1,* 1 Institute of Engineering Thermophysics, Chinese Academy of Sciences

    6. Power transformer parameters identification using extended kalman filter

    Kourosh Mousavi Takami, TDI researcher and phd student in Malardalen University , Jafar Mahmoudi , Erik Dahlquist, Malardalen University

    7. An advanced energy saving method for Aluminium - iron - copper bonding using explosive welding

    Scientific session on Energy savings in houses

    Chairman: Jurek Pyrko, Lund University

    . Mohammad Tabatabaee. TDI institute, Teheran, Iran and Mälardalen University

    8. Design of hot water user profiles for Swedish households based on time diaries.

    751 21 Uppsala, Sweden

    Magdalena Lundh, Ewa Wäckelgård, Kajsa Ellegård. Department of Engineering Sciences The Ångström Laboratory Box 534

    9. Modeling Household Electricity Load from Time-Use Data

    . Joakim Widén, Kajsa Ellegård och Ewa Wäckelgård. Department of Engineering Sciences,Solid State Physics,Uppsala University

    10. Investigation of electricity consumption in single houses with electrical heating alone and together with complementary heating systems

    . Cajsa Bartusch, Fredrik Wallin, Erik Dahlquist, Mälardalen University.

    11. Differences in electricity and hot water consumption in apartments of different sizes.

    Iana Vassileva, Cajsa Bartusch, Erik Dahlquist. Mälardalen University.

    12. Novel Architect Designs Energy-Saving Iranian Homes

    . S.M. Esmail Mousavi-Takami, TDI Technical Development Institute, Teheran, Iran

    13. Inform me please! - Energy use information to households and Demand Response

    . Jurek Pyrko, Energy Sciencees, Lunds University

    14. "Consumers, energy and IT. IT and other tools to support efficient energy consumption"

    I.C. MariAnne Karlsson Chalmers University of Technology, Product and Production Development

    15. Influence of Residential Ventilation on Radon Mitigation with Energy Saving emphasis

    Keramatollah Akbari, Mälardalen University and TDI in Teheran, Iran

    16

    . Extracting alumina from bauxite ore in jajarm factory process simulation using aspen software

    Mohammad Farrokh and Jafar Mahmoudi, Mälardalen University and TDI in Teheran, Iran

    17. Description of techniques for hot spot monitoring and detection in power transformers

    Hassan gholinejad, Kourosh Mousavi Takami and Jafar Mahmoudi, Mälardalen University and Tanesh Company, Iran

  • 106.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Avelin, Anders
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    CFB Black liquor gasification – Discussions of gasification and system solutions2009Ingår i: Proceedings of first International Conference on Applied Energy / [ed] Jinyue Yan, Hong-Kong University , 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper a new type of black liquor gasification process is presented and analyzed. It is a Circulating Fluidized Bed (CFB) process with the addition of TiO

    2 to the bed material. This gives a direct caustization of Na2CO3 to Na2O.TiO2 which forms NaOH by leaking with water. Thus a lime kiln is not needed in the process. Simultaneously SO4 is also reduced to S2- and stripped off as H2S to a major extent, absorbed in a selective scrubber, giving a separation of OH- and S2- , which makes modified cooking possible. Performance of integrating black liquor gasification has also been analyzed and discussed for electricity production in an efficient Integrated Gasification Combined Cycle (IGCC) and/or different chemicals such as NH3, DME or methanol in a polygeneration sytem.

  • 107.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hellstrand, S.
    Nolby Ekostrategi, Kil, Sweden.
    Preface2017Ingår i: Natural Resources Available Today and in the Future: How to Perform Change Management for Achieving a Sustainable World, Springer International Publishing , 2017, s. v-viKapitel i bok, del av antologi (Refereegranskat)
  • 108.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hellstrand, StefanMälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation. Nolby Ekostrategi, Kil, Sweden.
    Natural resources available today and in the future: How to perform change management for achieving a sustainable world2017Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
    Abstract [en]

    This book focuses on providing an overview of all our available natural resources, considering the sustainability and potential for power generation of each. Energy efficiency prospects of each natural resource are examined in the context of society's key energy needs- Heating/cooling, Electric Power, Transportation and Industrial Production. Geography, climate and demographics are all discussed as key vectors impacting the comparative opportunities for self-sustenance around the globe. The authors provide in-depth coverage of renewable energy upscale and energy efficiency improvements in industry and society within a historical context, including a keen look at the variable effectiveness of different policy tools that have been used to support the transition away from unsustainable resource use. Finally, suggestions for more sustainable futures are provided, from improved policy measures, to new technological horizons in areas from offshore wind and marine energy to biogas and energy storage. 

  • 109.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Comparison of Gas Quality from Black Liquor and Wood Pellet Gasification Using Modelica Simulation and Pilot Plant Results2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 992-998Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a potential to integrate biomass gasification with pulp & paper and CHP plants in order to complement the existing systems with production of chemicals, such as methane, hydrogen, and methanol etc. To perform system analysis of such integration, it is important to gain knowledge of relevant input data on expected synthesis gas composition by gasifying different types of feed stock. In this paper, the synthesis gas quality from wood pellets gasification (WPG) has been compared with black liquor gasification (BLG) through modeling and experimental results at pilot scale. In addition, the study develops regression models like Partial Least Squares (PLS) made from the experimental data. The regression models are then combined with dynamic models developed in Modelica for the investigation of dynamic energy and material balances for integrated plants. The data presented in this study could be used as input to relevant analysis using e.g. ASPEN plus and similar system analysis tools. 

  • 110.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology (KTH), Sweden.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hartwell, Philip
    BioRegional MiniMills Ltd, UK.
    Experimental and numerical investigation of pellet and black liquor gasification for polygeneration plant2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, s. 1066-1064Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is vital to perform system analysis on integrated biomass gasification in chemical recovery systems in pulp and paper and heat and power plants for polygeneration applications. The proposed integration complements existing pulp and paper and heat and power production systems with production of chemicals such as methane and hydrogen. The potential to introduce gasification-based combined cycles comprising gas turbines and steam turbines to utilize black liquors and wood pellets also merits investigation. To perform such analysis, it is important to first build knowledge on expected synthesis gas composition by gasifying at smaller scale different types of feed stock. In the present paper, the synthesis gas quality from wood pellets gasification has been compared with black liquor gasification by means of numerical simulation as well as through pilot-scale experimental investigations. The experimental results have been correlated into partial least squares models to predict the composition of the synthesis gas produced under different operating conditions. The gas quality prediction models are combined with physical models using a generic open-source modelling language for investigating the dynamic performance of large-scale integrated polygeneration plants. The analysis is further complemented by considering potential gas separation using modern membrane technology for upgrading the synthesis gas with respect to hydrogen content. The experimental data and statistical models presented in this study form an important literature source for future use by the gasification and polygeneration research community on further integrated system analysis.

  • 111.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Energiprocesser.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Energiprocesser.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hartwell, Philip
    BioRegional MiniMills Ltd., United Kingdom.
    Modeling of Black Liquor Gasification2016Konferensbidrag (Refereegranskat)
  • 112.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Energiprocesser.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH, Energiprocesser.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hartwell, Philip
    BioRegional MiniMills Ltd., United Kingdom.
    Modeling of Wood Gasification in an Atmospheric CFB Plant2016Konferensbidrag (Refereegranskat)
  • 113.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nordlader, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Christian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB Process Industries AB, Västerås, Sweden.
    Avelin, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Control of waste water treatment combined with irrigation2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In waste water treatment using biological treatment processes normally phosphorous, nitrous compounds as well as organic matterare removed.It is also important to remove or kill pathogens that otherwisecould cause diseases. The surplus of bio-sludge is used to produce biogas. In thepaper four different alternatives for system design and operations of systems was discussed. The alternatives integrates thewaste water treatment and irrigation offarmland using the water taken out from different positions in the waste water treatment plant.

  • 114.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Palm, Jenny
    Proceedings of the Scientific Conference on Energy and IT at Alvsjo fair, Stockholm March 11-12, 2009 in connection with the “Energitinget 20092009Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
    Abstract [en]

    Editors: Dahlquist E. and Palm J. 2009 Proceedings of the Scientific Conference on Energy and IT at Alvsjo fair, Stockholm March 11-12, 2009 in connection with the “Energitinget 2009” This is a joint scientific conference on Energy and IT between Mälardalen University and the Research School Program Energy Systems in Cooperation with Swedish Energy Agency. The papers are peer reviewed. ISBN number 978-91-977493-4-3.

    Energy savings potentials and social change in the use of residential electricity

    Mats Bladh,

    Adoption of energy efficiency measures in detached houses: Perception of homeowners

    Giresh Nair, Mid Sweden University

    Households, energy use and scenarios of energy efficiency of everyday life activities

    Anna-Lisa Lindén, Lund University

    The role of energy advisors on adoption of energy efficiency measures in detached houses

    Krushna Mahapatra, Mid Sweden University

    Perceptional and socio-economic factors in adoption of low energy houses

    Krushna Mahapatra, Mid Sweden University

    Consumption patterns today and tomorrow with respect to energy and how the energy

    system will be affected by this

    Iana Vassileva, Malardalen University

    CO2 emissions from general district heat use in Sweden – a method for justified

    comparisons in residential energy use

    Magnus Åberg,

    Applying an interdisciplinary perspective on industrial energy efficiency

    Jenny Palm, Dept. of Technology and Social Change, Linköping University and the national

    research school the Energy system Programme

    Markov-Chain Modelling of High-Resolution Activity ,Patterns and Household Electricity

    Demand

    Joakim Widén, Department of Engineering Sciences.Uppsala University

    From electricity to heat – a discourse analytic policy study of energy conversion at national,

    municipal and household level

    Karin Perman, Energi och Miljöteknik, University College Dalarna

    Case study of mobilized energy storages for distributed heating

    Weilong Wang, Mälardalen University and South China University of Technology

    International Scientific Conference on “Energy systems with IT” in connection with the

    Energiting 2009, March 11

    ‐12 at Älvsjö fair, Stockholm.

    Page 3 of 238

    Bio-refinery system of DME or CH4 production from black liquor gasification in pulp mills

    M Raza, Energy Processes, KTH

    Numerical and experimental study of the inclined free fins applied for thermal management

    Bijan Karimpourian, Malardalen University

    Simulation of ambient temperature effect on large-scale power transformer load ability

    Hasan Gholinejad, Malardalen University

    Process control in steel core production to optimize of power dissipation in electrical

    machines and transformers

    Kourosh Mousavi Takami, TDI, Malardalen University

    Evaluation of magnetic aging in transformers and electrical machines cores during

    operation

    Kourosh Mousavi Takami, TDI, ACECR, Malardalen University

    A simple method for removing leakage of metal pipes, like district heating- and NG pipes

    Mohammad Tabatabaeeghomi, Mälardalen University, Vasteras, Sweden also Technology

    Development Institute (TDI), ACECR, Tehran, Iran

    Modeling of Radon Transport trough Building Materials and ventilation

    Keramatollah Akbari, TDI, ACECR, Malardalen University

    Energy efficient window development – Historical overview of the development of energy

    efficient windows in Sweden

    Bernadett Kiss,

  • 115.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mårtensson, Kenneth
    Enander, Måns
    How to develop a fossil fuel free Malardalen Region2007Konferensbidrag (Refereegranskat)
  • 116.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Tomas-Aparicio, Elena
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Jansson, Johan
    SAPPI South Africa.
    On-line simulations for diagnostics and control2010Ingår i: International Control Systems 2010 Proceedings / [ed] Alf Isaksson, Stockholm: SPCI , 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    The main objective of this project is to develop an application where physical models of fibre lines are run in parallel to the real processes. This application can be useful as a diagnostic tool to detect faults and improve process operations. By running the simulation models continuously, feeding input data from the process data base at a pre-determined time interval, the simulation will show results from the “normal operations”. These simulation results are compared to the measured data and hence faults can be detected e.g. hang-ups in the digester and channelling. NIR-spectra lab measurements of the wood chips fed into the digester can as well be considered. This feature give us the possibility of correlating the quality of the obtained pulp to the raw material used, which can be of help when tuning the process parameters.

    In this paper results from the use of the application described above in several mills in South Africa and results from some preliminary tests in a mill in Sweden are presented. Moreover, the system structure for the interaction between the physical models designed in Modellica language and the real process data is described.

  • 117.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Vassileva, Iana
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Campillo, Javier
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lundström, Lukas
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Energy efficiency improvements by renovation actions: in Lagersberg and Råbergstorp, Stoke on Trent and Allingsås2016Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report covers evaluation of some renovation projects and compares energy saving effects versus renovation costs.

    It can be seen that advanced renovation to passive house standard is significantly more expensive than “normal” renovation, but also gives significant improvement by a 62 % reduction of total energy and 85 % reduction in heat demand. The cost associated with the renovation is somewhere in the range of 130–570 €/m2, depending on how the total renovation costs are split between energy and other aspects. Probably somewhere in-between is most correct. This can be compared to mostly better heat control by measuring temperature in every third apartment and controlling heat supply to keep a constant temperature. This gives the possibility to have a significantly lower set point, 21 ºC instead of 24 ºC as earlier. Together with some other actions, 34 % energy savings were achieved at a cost of 28 €/m2. Also renovations with significantly more actions were evaluated, where the cost also is in-between.

    From this we can conclude that with more advanced and costly renovations we can achieve very strong reductions, which may be feasible if the renovation demand is high anyhow, while cheap and low cost actions can be good enough for quite good buildings.

    Also behavior with respect to energy use was evaluated. We here can see that the use is very different in different apartments depending on behavior. Energy information actions were giving positive effects on energy demand for the majority of investigated tenants, while approximately 25 % did not reduce or even increased their consumption.

  • 118.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Vassileva, Iana
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Optimization of the energy system to achieve a national balance without fossil fuels2010Ingår i: International Green Energy Conference, IGEC-V June 1-3, 2010, Waterlo, Ontario, Canada / [ed] Xianguo Li, Waterloo,Canda: University publications , 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we discuss the overall balance for Sweden and to some extent EU27 with respect to both power and heat production in relation to how the energy is utilized. This includes transportation, where we compare the system of today with a possible future system with hybrid-electric vehicles, renewable fuels and reductions of total consumption, through both better vehicles, as well as better logistics for transportation of goods. Concerning industry use energy improvements through more efficient industrial processes is discussed. For households, offices and manufacturing industries energy efficient buildings and individual behavior with respect to energy use is discussed. New sources for power will be less stable, like wind and solar power. A special focus is on biomass utilization and production. This also includes food. The situation today is compared to the potential balance after implementation of the actions discussed in the paper. The overall conclusion is that it should be relatively easy for Sweden to reach a sustainable society, if just the political will is present. It is also shown that there is a good potential also for the complete EU 27, but the actions are significantly more demanding to reach the balance, although in no way impossible.

  • 119.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, inyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    How to become independent of fossil fuels in Sweden2008Ingår i: quist / [ed] Lui Ronghou, Shanghai: SJTU press , 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sweden has got the toughest demand in the whole of Europe recently. In 2020 minimum 49 % of the energy should be renewable energy. To achieve the goal biogas production is being optimized, utilizing organic wastes and crops, to produce methane for cars and buses. In Vasteras a 200 MW waste gasification plant will be built to replace coal in an existing 600 MW PC-boiler with biogas. The plant will start up 2011. There will be co-firing with also peat, aside of the biogas. In Sweden 120 TWh/y of biomass is consumed, which is almost 1/3 of the total 400 TWh energy utilized annually. Most of it is used in co-generation (CHP) or pulp and paper industry. Now the plan is to increase production of liquid fuels for vehicles. Energy balances for production of bio ethanol in Sweden will be discussed. This can be an interesting part of poly-generation systems. Plug-in hybrid car are foreseen to be introduced on a large scale within the next 10 years. Here liquid fuels are used in a combustor with e.g. a turbine and generator primarily to produce electricity, while electric engines fed by electricity from batteries drive the vehicle. Today 60 % of the new cars are "environmental", that is low consuming diesel, ethanol or biogas. Seven years ago it was only 5 % of the new cars! Cities, county authorities and government are working together with companies and universities to drive the transfer away from fossil fuels.

  • 120.
    Dai, B.
    et al.
    Tianjin University of Commerce, Tianjin, China.
    Liu, S.
    Tianjin University of Commerce, Tianjin, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin University of Commerce, Tianjin, China.
    Sun, Z.
    Tianjin University of Commerce, Tianjin, China.
    Song, M.
    The University of Tokyo, Chiba, Japan.
    Yang, Q.
    Tianjin University of Commerce, Tianjin, China.
    Ma, Yitai
    The University of Tokyo, Chiba, Japan.
    Energetic performance of transcritical CO2 refrigeration cycles with mechanical subcooling using zeotropic mixture as refrigerant2018Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 150, s. 205-221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transcritical CO2 refrigeration cycle integrated with mechanical subcooling (MS) cycle operating with zeotropic mixture is proposed in this study, based on the concept of Lorenz cycle. An energetic model is developed and analyses are conducted in detail. A maximum overall coefficient of performance (COP) is achieved at the optimum discharge pressure and optimum subcooling degree. The maximum overall COP, optimum subcooling degree and discharge pressure are closely related to the temperature glide of the mixtures. The energy efficiency of the transcritical CO2 refrigeration cycle can be efficiently improved, and the high pressure can be reduced when mixtures with proper temperature glide are used as MS cycle refrigerant. Compared with pure R32, the overall COP is enhanced by 4.91%, and the discharge pressure decreases by 0.11 MPa at evaporation temperature of −5 °C and ambient temperature of 35 °C when R32/R1234ze(Z) (55/45) is employed as MS refrigerant. The mixtures with proper temperature glide are recommended. The thermal performance of the overall cycle can be enhanced more significantly for hot and warm climate regions, or relative low evaporation temperature applications, though a high subcooling degree is required to meet the optimum operation condition.

  • 121.
    Dai, B.
    et al.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Qi, H.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Liu, S.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Ma, M.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Zhong, Z.
    Foreign Economic Cooperation Office, Ministry of Ecology and Environment of the People's Republic of China, Beijing, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Song, M.
    Department of Human and Engineered Environmental Studies, The University of Tokyo, Chiba, Japan.
    Sun, Z.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Evaluation of transcritical CO 2 heat pump system integrated with mechanical subcooling by utilizing energy, exergy and economic methodologies for residential heating2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 192, s. 202-220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A transcritical CO 2 heat pump (HP) system for residential space heating integrated with direct dedicated mechanical subcooling (DMS) is proposed, and mathematical models are developed to study the annual energetic and economic performances considering the influence of frosting. The operation characteristics by adopting different heating terminals used in five typical cities are also assessed. The results show a maximum coefficient of performance (COP) is achieved at the optimum discharge pressure and subcooling degree. The COP is promoted by 24.4% and the discharge pressure is decreased by 2.093 MPa at the ambient temperature of −10 °C and water supply/return temperature of 45/40 °C. The seasonal performance factor (SPF) is enhanced more noticeably for severe cold region. For the case of Harbin using floor-coil radiator (FCR) or normal fan-coil unit (N-FCU) as heating terminal, SPF is improved by 32.0%. The highest SPF is achieved when small temperature difference fan-coil unit (STD-FCU) is employed. The exergy efficiency can also be apparently improved, especially for the cities located in severe cold region and using FCR or N-FCU as heating terminal due to the reduction in throttling loss of CO 2 system. The purchased equipment cost and electricity cost of the CO 2 HP with DMS are both lower than those of traditional CO 2 heat pump system. The CO 2 HP DMS system using STD-FCU as heating terminal shows superior economical efficiency to traditional system, with levelized annual total cost reduced by 7.51–15.27%. 

  • 122.
    Dai, Baomin
    et al.
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Qi, Haifeng
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Liu, Shengchun
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Zhong, Zhifeng
    Minist Ecol & Environm Peoples Republ China, Foreign Econ Cooperat Off, Beijing, Peoples R China..
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China.
    Song, Mengjie
    Univ Tokyo, Dept Human & Engn Environm Studies, Chiba 2778563, Japan..
    Ma, Muyu
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Sun, Zhili
    Tianjin Univ Commerce, Tianjin Key Lab Refrigerat Technol, Tianjin 300134, Peoples R China..
    Environmental and economical analyses of transcritical CO2 heat pump combined with direct dedicated mechanical subcooling (DMS) for space heating in China2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 198, artikel-id 111317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An environmental and economical assessment model is developed, in order to evaluate the performances of transcritical CO2 heat pump system with dedicated mechanical subcooling (CO2 HPDMS). Introducing DMS to traditional CO2 HP system is an efficient method to reduce the primary energy consumption, which can be further decreased by using small temperature difference fan-coil unit (STD-FCU) as heating terminal. Using CO2 heat pump system for space heating is an environmentally-friendly heating method. The corresponding pollution emissions are only inferior to those of the wall hanging gas heater. The initial capital cost and operating cost of CO2 HPDMS system are both lower than those of CO2 HPBASE system, and the CO2 compressor cost accounts for about 80% of the overall initial capital cost. In contrast to other traditional heating methods, the payback periods of CO2 HPDMS system are not more than 9 years in most cases. If the CO2 compressor and electricity price are reduced by 20% and 28.79% respectively, the life cycle cost of CO2 HPDMS will be competitive to that of coal-fired boiler. In China, it is a promising way to adopt CO2 HPDMS for space heating in the near future with the assistant of electricity price subsidy and compressor price reduction.

  • 123.
    Dalenbäck, Jan-Olof
    et al.
    Chalmers tekniska högskola, Göteborg, Sverige.
    Lennermo, Gunnar
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energianalys AB, Sverige.
    Andersson-Jessen, Per-Erik
    Kovacs, Peter
    Solvärme i fjärrvärmesystem: Utvärdering av primärkopplade system2013Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Sverige ärett föregångsland när det gälleratt använda solvärme i när-och fjärr-värmesystem.Under perioden 1982 till 1992 byggde vi en serie av anläggningar som alla var större än man byggt i något annat land. Stora bioenergitillgångar och ett stort behov att hitta ersättning för olja i fjärrvärme-systemen ledde parallellt till en mycket positiv utveckling för biobränsle i fjärr-värmesystem, främst flis, och tillsammans med ändrade villkor för demonstrations-anläggningar, kom intresset för stora solvärmeanläggningar av sig i Sverige.

    Med Bo01 i Malmö 2001 introducerades lokala solvärmesystem i fjärrvärme och med stöd från EU-direktiv med byggnadsfokus har det nu byggts ett antal mindre solvärmeanläggningar i anslutning till olika byggnader med fjärrvärme. De anläggningar som uppfördes på 80-och 90-talet ingick ofta i ett samordnat program med investeringsbidrag och tredjepartsutvärdering och det finns en mängd utvärderingsrapporter.De anläggningar som uppförts under 2000-talet har inte haft samma förutsättningar.Dessutom är det förhållandevis många som anslutits i fjärr-värmesystem.

    De har ofta initierats genom politiska beslut till del som ett resultat av nya krav på byggnaders energiprestanda och det finns inga andra utvärderingar än anläggningsägarnas egna. I den här rapporten görs en övergripande dokumentation och utvärdering av 22solvärmesystem som anslutits direkt till fjärrvärmesystemen och tagits i drift under perioden 2000till 2010. Utvärdering fokuserar på systemutformning, installation, driftuppföljning och värmeutbyte som kan ligga till grund för rekommendationer till nya anläggningar.

    Utvärderingen visar att många av anläggningarna har brister såväl med avseende på systemutformning som pådriftuppföljning och värmeutbyte.Det finns anlägg-ningar som ger mer än 300 kWh/år.m2solfångare, vilket får anses acceptabelt, men som medelvärde ger de 8 senast uppförda anläggningarna endast 240 kWh/år.m2 solfångare (2011-2012), varför det finns stort utrymme för förbättringar.

    Som en övergripande rekommendation föreslås att det bör genomföras ett upp-följningsprojekt under 2013 där de utvärderade anläggningarna följas upp under minst ett år så att alla fås att fungera på ett relevant sätt utgående från dess förutsättningar. Sedan bör erfarenheterna från de utvärderade anläggningarna sammanställas i en enkel projekteringsmall som kan användas i framtida anläggningar.

  • 124.
    Danielsson, Gustav
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Inomhusklimatets påverkan på energianvändning i kontorsbyggnader: En undersökning hur byggnadskonstruktioners värmelagringsförmåga påverkar energianvändningen och människors upplevelse av inomhusklimatet vid olika värmesystem, temperaturintervaller samt olika kontor2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 125.
    Danish, M.
    et al.
    East China University of Science and Technology, Shanghai, China .
    Gu, X.
    East China University of Science and Technology, Shanghai, China .
    Lu, S.
    East China University of Science and Technology, Shanghai, China .
    Ahmad, A.
    Muhammad Nawaz Sharif University of Engineering and Technology, Multan, Pakistan.
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Farooq, U.
    East China University of Science and Technology, Shanghai, China .
    Zhang, X.
    East China University of Science and Technology, Shanghai, China .
    Fu, X.
    East China University of Science and Technology, Shanghai, China .
    Miao, Z.
    East China University of Science and Technology, Shanghai, China .
    Xue, Y.
    East China University of Science and Technology, Shanghai, China .
    Efficient transformation of trichloroethylene activated through sodium percarbonate using heterogeneous zeolite supported nano zero valent iron-copper bimetallic composite2017Ingår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 308, s. 396-407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zeolite supported nano zero valent iron copper bimetallic composite (Z-nZVFe-Cu) was synthesized using an ion exchange method. The morphology and physico-chemical properties of the Z-nZVFe-Cu composite were determined using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), energy dispersive X-ray spectra (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). The results showed that iron and copper nano particles were well dispersed on the zeolite sheet. The degradation efficiency of trichloroethylene (TCE) achieved was more than 95% using Z-nZVFe-Cu as a heterogeneous Fenton like catalyst. An efficient removal of total organic carbon (TOC) was promoted as compared to zeolite supported iron nano composite (Z-nZVFe) and unsupported nano iron (nZVFe). Electron spin resonance (ESR) detection confirmed the intensity of hydroxyl radicals (OH[rad]) in the system. While benzoic acid (BA), a probe indicator for the quantification of OH[rad], demonstrated the higher intensity of hydroxyl radicals in Z-nZVFe-Cu as compared to Z-nZVFe and nZVFe. The less iron and copper leaching of from Z-nZVFe-Cu presented its higher stability and better catalytic activity, displaying its potential long term applications for TCE degradation in groundwater. 

  • 126.
    Danish, Muhammad
    et al.
    E China Univ Sci & Technol, Peoples R China.
    Naqvi, Muhammad
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Farooq, Usman
    Gujarat Univ, Gujrat, Pakistan.
    Naqvi, Salman
    Univ Teknol PETRONAS, Univ Teknol PETRONAS, Malaysia.
    Characterization of South Asian agricultural residues for potential utilization in future 'energy mix'2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 2974-2980Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper characterizes various locally available agricultural residues in South Asian region to evaluate their potential as feedstock for renewable energy production and contributing toward solving energy crisis and environmental issues. The thermo-chemical characterization has been performed in order to determine if the residues have potential to be used in biomass conversion technologies producing combined heat and power. The characterization methods for comparing different agricultural residues include proximate and ultimate analysis, heating value, ash content, thermo gravimetric analysis (TGA) and structural composition analysis (SCA). Widely available agricultural wastes in South Asian region were selected for the characterization i.e. bagasse, almond shell, corn cob, cotton stalks, wheat straw, sawdust, corn leaf, rice husk, rice straw, and corn straw. The analysis showed that the corn cob had the highest moisture content that will result in low energy efficiency of the thermal conversion technology due to energy requirement for drying. Whereas almond shell had the lowest moisture content. Ash and volatile contents were found to be highest in rice straw and almond shell respectively. The thermo gravimetric analysis showed that most of the agricultural residues can be easily decomposed and represent potential feedstock for biomass flexible combined heat and power systems through pyrolysis or gasification. (C) 2015 Published by Elsevier Ltd.

  • 127.
    Daraei, Mahsa
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Production planning of CHP plants integrated with bioethanol production and local renewables2019Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Production planning of an energy system is dependent on parameters such as energy demand and energy conversion technologies, which are influential in making decisions on operation strategy and optimal performance of the system. In accordance with the European Union energy policy, the share of renewable resources in the energy supply is growing. Improvement in energy technology is considered to be a pathway to achieve the target of 100% renewable power supply in Sweden by 2040. Increased utilization of renewable resources in energy systems and transportation sectors as well as improved energy conversion technologies would add complexity to the systems. Development of such complex systems depends on several key parameters, including availability of local resources, changes in daily energy use behavior, market price and weather conditions. Therefore, optimization and long-term production planning of such systems will be crucial considering the alternating nature of renewable resources.  

    The aim of this thesis is to develop an optimization model for a regional energy system to provide advanced knowledge for production planning for combined heat and power (CHP) plants. The energy system in the county of Västmanland in central Sweden is used as the case for study. The regional system consists of CHP plants, heat only boilers and renewable resources. Two different optimization cases are developed for the analysis, one with increased energy supply from local renewables, and the other with integrated transport fuels production in a polygeneration system. The model includes the whole chain from availability of resources to the final energy use. 

    The effect of different parameters relating to trends in energy demand and supply on operational strategy of the studied system is investigated by developing different scenarios. The potential solar power production from grid-connected solar cells installed on the rooftops of buildings in the region is added to the system in the base scenario. Then, the first scenario analyzes the increased application of heat pumps to replace the district heating in some of the buildings in the region. The influence of electrification of the transportation system as a result of increased penetration of electric vehicles is investigated in the second scenario. Two further scenarios evaluate the effects of integration of bioethanol production with existing CHP plants and increased application of bioethanol cars and hybrid vehicles in the regional transportation system. 

    The study demonstrates the importance of production planning of the energy system at the regional scale in relation to resource availability and energy imports. The main conclusion of this thesis is that the polygeneration and increased use of heat pumps could influence the production planning of the system in terms of fuel use, plants operation, fossil-based emissions, and energy demand and import. However, increased use of hybrid vehicles represents the optimal case for the mentioned parameters.

  • 128.
    Daraei, Mahsa
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Avelin, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Evaluation of biofuel production integrated with existing CHP plants and the impacts on production planning of the system – A case study2019Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 252, artikel-id 113461Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing atmospheric CO2 concentration has caused a transformative shift in global energy systems, which is contributing to an increased use of renewables. Sweden is among the countries trying to shift to a fossil-fuel-free system in all energy sectors. This paper addresses the fuel demand and supply in the transportation sector in the county of Västmanland in Sweden. A Mixed Integer Linear Programming optimization model is developed to minimize cost in the studied system. The model is further used to investigate the influence of three different scenarios on production planning of regional Combined Heat and Power (CHP) plants: (1) straw-based biofuel production integrated with existing CHP plants to fuel combustion engine vehicles, (2) use of electric vehicles, and (3) use of hybrid vehicles fueled by both electricity and bioethanol. Potential solar power generation from rooftop solar cells is also included in the model. The energy system in scenario 2 is found to have the highest overall system efficiency; however, a large amount of power needs to be imported to the system. Hybrid vehicles can potentially reduce the electricity import and CO2 emissions compared to the current situation. Electricity production from rooftop solar collectors could provide the energy needs of the vehicles during summer, while regionally produced straw-based bioethanol integrated with CHP plants can satisfy the fuel needs of the vehicles in winter. This approach could affect the production planning of CHP plants, result in less fuel use and increase the share of renewable resources in the regional transportation system. 

  • 129.
    Daraei, Mahsa
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Avelin, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Optimization of a regional energy system including CHP plants and local PV system and hydropower: Scenarios for the County of Västmanland in Sweden2019Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 230, s. 1111-1127Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Providing the energy needs of the cumulatively increasing population has become a challenge for the regional energy systems in the world. The most critical challenge is to supply enough energy in the forms of heat and power during the cold and warm periods of the year with the lowest production cost and minimum environmental impacts. A solution is to increase the green energy supply from renewable energy resources such as solar, wind power, and hydropower. In order to apply this solution in the real energy system, potentials for clean energy supply in an optimized manner should be evaluated. In this study, an optimization model is developed for a regional energy system in the central part of Sweden. The studied system consists of Combined Heat and Power (CHP)plants and heat water boilers together with renewable energy supply from rooftop Photo Voltaic (PV)- solar collectors and regional hydropower plants. The General Algebraic Modeling System (GAMS)is used to create the model based on the Mixed Integer Linear Programming (MILP)method. The goal is to evaluate the influence of local renewable energy systems on the production planning of CHP plants in a region. Two different scenarios are investigated based on the extremes in energy supply and demand concerning the increased use of Electrical Vehicles (EVs)and more application of Heat Pumps (HPs)in the system. The results show that installation of rooftop PV systems has the potential to reduce the electricity import to the region; however, it will at the same time reduce the operation time of the CHP plans during the summer period. With increased use of HPs for heating, the shut off time for CHP plants is further increased. Increase in electric passenger cars penetration in the system has no impacts on the production profiles of the plants. The regional electricity demand grows significantly by more utilization of EVs and increased application of heat pumps in the studied system. The high electricity demand will mainly be satisfied by importing electricity from outside the region together with low production from CHP plants and the power generated by the rooftop PV systems and regional hydropower. The developed optimization model with studied scenarios can be applied to other energy systems to increase the knowledge of production planning and feasibility of a fossil fuel free energy system.

  • 130.
    Davidsson, H.
    et al.
    Lund University, Sweden.
    Bernardo, R.
    Lund University, Sweden.
    Gomes, J.
    Solarus AB, Älvkarleby, Sweden.
    Gentile, N.
    Lund University, Sweden.
    Gruffmanc, C.
    ÅF AB, Gävle, Sweden .
    Chea, L.
    Universidade Eduardo Mondlane, Maputo, Mozambique .
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Construction of laboratories for solar energy research in developing countries2014Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 57, s. 982-988Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A large number of photovoltaic systems have been installed in developing countries around the world during numerous projects. The goal is often to improve the quality of life in rural areas often lacking electricity. Many of these installations provide important services such as lighting and charging of various devices. However, when the projects are finished, there is a large risk that maintenance is not carried out properly and that malfunctions are never repaired. This situation can leave an otherwise well- functioning system unusable. A key problem is that there are not enough trained technicians that can maintain and repair the system locally. One reason for this is the lack of practical education in many developing countries. Furthermore, the availability of spare parts is essential for long term effectiveness. During 2011 a group of researchers from Lund University in Sweden built a small scale laboratory in Maputo, Mozambique, with local researchers. The project was successful and today the laboratory functions both as a teaching facility and as a measurement station for solar energy research for licentiates, masters and Ph.D. students. The main goal now is to widen the project in order to incorporate more universities in developing countries. We are now looking for new interested partners in developing countries who believe that such a laboratory could strengthen their ability to teach practical work and to perform research at a local university. Partners for planning and executing the project are also needed.

  • 131.
    Dibdiakova, Janka
    et al.
    Norwegian Institute of Bioeconomy Research, Ås, Norway..
    Liang, Wang
    Sintef Energy Research, , Norway.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Heating Value and Ash Content of Downy Birch Forest Biomass2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 1302-1308Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biomass from forestry sector provides an important contribution to meet the government's targets for increasing bioenergy production and utilization. Characterization of forest residues is critical for exploiting and utilizing them for energy production purpose. In present work, stem wood, stem bark, branches, top of trees from downy birch forest were sampled from different sites in South Norway and subjected to heating value and ash content measurement. Properties of different parts of trees vertically along the tree trunk and radially along the branch and crown level were assessed via the statistical model. The heating value of stem wood was in range 18.14-18.57 MJ/kg, of stem bark 18.50-18.72 MJ/kg and of branch wood 18.21-18.50 MJ/kg. The vertical dependence of heating value of downy birch stem wood was similar to that of stem bark. Regular decreasing of heating value towards the tree top was observed. Significantly higher heating value at level p<0.05∗of stem bark than the one of stem wood was observed. The ash content of downy birch branch wood did vary axially along the branch whereas there are only slight differences of ash content of branch within the crown. The stem bark has the highest ash content in range 2.0-2.5%, followed by branch wood in range of 1.0-1.6% and the lowest for stem wood in range of 0.3-0.5%.

  • 132.
    Dibdiakova, Janka
    et al.
    Norwegian Forest & Landscape Inst, Norway.
    Wang, Liang
    Sintef Energy Res, Trondheim, Norway.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Characterization of ashes from Pinus Sylvestris forest biomass2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 186-191Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Efficient and profitable biomass combustion is often limited by ash related operational problems. Knowledge of the ash melting and sintering is of important, in terms of predict and reduce ash-related problems in biomass-fired boilers. In this study, chemical composition and melting behaviors of ashes from the four parts of P. sylvestris trees were investigated. The four parts from Pinus sylvestris trees are stem wood, bark, branch base and twigs. A simultaneous thermal analyzer (STA) was used to characterize the melting behavior of selected biomass fuels in oxidizing atmosphere. Ash melting process was identified as the distinctive endothermic peaks on recorded DSC curves. The results showed that the stem wood of pine contains higher contents of most of the ash forming matters than other tree parts. Chemical composition of ashes from four parts of the pine tree is dominated by element Ca, K, Mg, Mn, P and Si. The K, Na and P contents in the twigs are significantly higher than that of stem wood, bark, and branch base indicating high tendency of ash melting and slagging. STA experiments indicated that the melting process of the studied fuel ashes start in the temperature range of 930-965 degrees C. Scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometry (EDX). Analyses results showed that the stem wood ash remains loose structure even after 1000 degrees C sintering treatment. But the ashes originated from top branch show sign of sintering at 1000 degrees C. The obtained results of present work can be considered as useful information within an industry interest for a prediction of the forest biomass ash melting behavior. 

  • 133.
    Diehl, Stefan
    et al.
    Lund Univ, Ctr Math Sci, POB 118,Lund, Sweden..
    Zambrano, Jesus
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Carlsson, Bengt
    Uppsala Univ, Dept Informat Technol, POB 337, Uppsala, Sweden..
    Analysis of photobioreactors in series2018Ingår i: Mathematical Biosciences, ISSN 0025-5564, E-ISSN 1879-3134, Vol. 306, s. 107-118Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A photobioreactor (PBR) contains microalgae which under illumination consume carbon dioxide and substrate dissolved in water, and produce oxygen. The process is used in water recovery resource facilities with a continuous flow of wastewaster through the PBR. With several PBRs in series the reduction of substrate can be improved. This paper contains a thorough analysis of a model of PBRs in series, where each PBR is modelled with a system of three ordinary differential equations for the concentrations of dissolved substrate and biomass (algae), and the internal cell quota of substrate to biomass. Each PBR has a certain volume and irradiation. The absorption rate of substrate into the cells is modelled with Monod kinetics, whereas the biomass growth rate is modelled with Droop kinetics, in which both a minimum and a maximum internal cell quota are assumed. The main result is that the model has a unique stable steady-state solution with algae in all PBRs. Another stable steady-state solution is the wash-out solution with no algae in the system. Other steady-state solutions are combinations of these two with no algae in some of the first PBRs and algae in the rest of the PBRs in the series. Conditions on the illumination, volumetric flow and volumes of the PBRs are given for the respective solution. Numerical solutions illustrate the theoretical results and indicate further properties.

  • 134.
    Ding, J.
    et al.
    Sun Yat-Sen University, Guangzhou, China.
    Pan, G.
    Sun Yat-Sen University, Guangzhou, China.
    Du, L.
    Sun Yat-Sen University, Guangzhou, China.
    Lu, J.
    Sun Yat-Sen University, Guangzhou, China.
    Wei, X.
    South China University of Technology, Guangzhou, China.
    Li, J.
    National Supercomputer Center in Guangzhou, Guangzhou, China.
    Wang, W.
    Sun Yat-Sen University, Guangzhou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Theoretical prediction of the local structures and transport properties of binary alkali chloride salts for concentrating solar power2017Ingår i: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 39, s. 380-389Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Comprehensive molecular simulations have been carried out to compute local structures and transport properties of different components of binary NaCl-KCl over a wide operating temperature range. The partial radial distribution functions, coordination number curves and angular distribution functions were calculated to analyze the influence of temperature and component on local structures of molten Alkali Chlorides. Transport properties were calculated by using reverse non-equilibrium molecular dynamics (RNEMD) simulations including densities, shear viscosity and thermal conductivity. The results show that ion clusters are considered to be formed and the distance of ion clusters become larger with increasing temperature which has great influence on macro-properties. The calculated properties have a good agreement with the experimental data, and similar method could be used to computationally calculate the properties of various molten salts and their mixtures.

  • 135.
    Ding, Y.
    et al.
    College of Electrical Engineering, Zhejiang University, Hangzhou, ChinaCollege of Electrical Engineering, Zhejiang University, Hangzhou, ChinaCollege of Electrical Engineering, Zhejiang University, Hangzhou, ChinaCollege of Electrical Engineering, Zhejiang University, Hangzhou, ChinaCollege of Electrical Engineering, Zhejiang University, Hangzhou, ChinaCollege of Electrical Engineering, Zhejiang University, Hangzhou, China.
    Shao, C.
    College of Electrical Engineering, Zhejiang University, Hangzhou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Division of Energy Processes, KTH-Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Song, Y.
    College of Electrical Engineering, Zhejiang University, Hangzhou, China.
    Zhang, C.
    Division of Energy Processes, KTH-Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Guo, C.
    College of Electrical Engineering, Zhejiang University, Hangzhou, China.
    Economical flexibility options for integrating fluctuating wind energy in power systems: The case of China2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 228, s. 426-436Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The inherent stochastic nature of wind power requires additional flexibility during power system operation. Traditionally, conventional generation is the only option to provide the required flexibility. However, the provision of the flexibility from the conventional generation such as coal-fired generating units comes at the cost of significantly additional fuel consumption and carbon emissions. Fortunately, with the development of the technologies, energy storage and customer demand response would be able to compete with the conventional generation in providing the flexibility. Give that power systems should deploy the most economic resources for provision of the required operational flexibility, this paper presents a detailed analysis of the economic characteristics of these key flexibility options. The concept of “balancing cost” is proposed to represent the cost of utilizing the flexible resources to integrate the variable wind power. The key indicators are proposed respectively for the different flexible resources to measure the balancing cost. Moreover, the optimization models are developed to evaluate the indicators to find out the balancing costs when utilizing different flexible resources. The results illustrate that exploiting the potential of flexibility from demand side management is the preferred option for integrating variable wind power when the penetration level is below 10%, preventing additional fuel consumption and carbon emissions. However, it may require 8% of the customer demand to be flexible and available. Moreover, although energy storage is currently relatively expensive, it is likely to prevail over conventional generation by 2025 to 2030, when the capital cost of energy storage is projected to drop to approximately $ 400/kWh or lower.

  • 136.
    Ditaranto, M.
    et al.
    SINTEF Energy Research, Trondheim, Norway.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hu, Y.
    University of South Wales, United Kingdom.
    Evaluation of a pre-combustion capture cycle based on hydrogen fired gas turbine with exhaust gas recirculation (EGR)2014Ingår i: Energy Procedia, 2014, s. 1972-1975Konferensbidrag (Refereegranskat)
    Abstract [en]

    Pre-combustion capture technology is a promising route to power generation with CO2 free emissions, by transforming the fossil hydrocarbon fuel into a hydrogen rich fuel with near zero Carbon containing species. This gaseous fuel also allows to use a high efficiency gas turbine into a coal based power plant. The gas turbine combustor however has to meet the challenge of high temperature flame responsible for unacceptable NOx emissions, and a highly reacting fuel impeding the use of conventional dry low NOx combustion technologies. The actual solution to this problem is to dilute the hydrogen fuel with up to 50% Nitrogen. This paper presents a concept where the exhaust gas of the gas turbine is recirculated (EGR) such as to deplete the air of oxygen to produce a low temperature combustion with undiluted hydrogen fuel while flame stability is still ensured by the highly reactive properties of hydrogen. The study compares the concept with a cycle using Selective Catalytic Reduction for NOx control.

  • 137.
    Ditaranto, M.
    et al.
    SINTEF Energy Research, Trondheim, Norway .
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Løvås, T.
    Norwegian University of Science and Technology, Trondheim, Norway .
    Concept of hydrogen fired gas turbine cycle with exhaust gas recirculation: Assessment of combustion and emissions performance2015Ingår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 37, s. 377-383Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel gas turbine cycle concept applicable to power plants with pre-combustion CO<inf>2</inf> capture or integrated gasification combined cycle (IGCC) is presented. These power plants use a hydrogen rich fuel with high reactive combustion properties which makes fuel dilution necessary to achieve low NOx emissions. The proposed novel gas turbine arrangement is set up as to avoid both fuel dilution and its consequent efficiency penalty, and breakthrough in low NOx combustion technology. In this concept, a high exhaust gas recirculation (EGR) rate is applied in order to generate an oxygen depleted working fluid entering the combustor, enough to reduce the high reactivity of hydrogen rich fuels. As a result, the combustion temperature in this environment is inherently limited, thus, keeping NOx formation rate low. A first order assessment of the combustion characteristics under such gas turbine operating conditions is made in the light of a numerical analysis of stability and NOx emissions potential. Both diffusion and premixed types combustor are considered according to the selected EGR rate. It is first shown that the flame stability could be maintained at EGR rates well above the maximum EGR limit found in conventional natural gas fired gas turbines. The study further shows that at these high EGR rates, considerable reductions in NOx emissions can be expected. The conclusion of this first order analysis is that there is a true potential in reducing the efficiency penalty induced by diluting the fuel in power plants with pre-combustion CO<inf>2</inf> capture. 

  • 138.
    Dong, Beibei
    et al.
    Tianjin Univ Commerce, Key Lab Refrigerat Technol Tianjin, Peoples R China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tianjin Univ Commerce, Key Lab Refrigerat Technol Tianjin, Peoples R China.
    Zhu, Kai
    Tianjin Univ Commerce, Key Lab Refrigerat Technol Tianjin, Peoples R China.
    PVTxy Properties of CO2 Mixtures for CCS: An Update of Experimental Data and Models Since 20092018Ingår i: JOINT INTERNATIONAL CONFERENCE ON ENERGY, ECOLOGY AND ENVIRONMENT ICEEE 2018 AND ELECTRIC AND INTELLIGENT VEHICLES ICEIV 2018, DESTECH PUBLICATIONS, INC , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    The latest progress on the experimental data and theoretical models regarding PVTxy properties of CO2 mixtures has been updated. This review shows that more experimental data are available, such as the vapor liquid equilibrium (VLE) of CO2/NO and the density of CO2/O-2. But there are still some clear deficiencies: for example, there have been no data on VLE of CO2/COS and density of CO2/NH3; there are only few points on VLE of CO2/NH3 and CO2/N2O, and density of binary mixtures containing CO, N2O4, COS and H2S. Several new models exhibit advantages for calculating PVTxy properties of CO2 mixtures. For example, Equation of State for Combustion Gases and Combustion Gas-like Mixtures (EOS-CG) shows better accuracy on both phase equilibrium and density than GERG-2008 except for the critical region. Peng-Robinson+ residual Helmholtz energy-based model (PR + EOS/(E,Wilson)(ares)) displays significant improvement in the representation of high-pressure critical region (deviation decreasing from 12.6% to 1% for CO2/O-2/N-2) and wider application of polar and non-polar mixtures for VLE.

  • 139.
    Dong, Shuaili
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. China Univ Petr, Beijing, Peoples R China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Avelin, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhang, Qi
    China Univ Petr, Beijing, Peoples R China..
    Yu, Zhixin
    Univ Stavanger, Dept Energy & Petr Engn, Stavanger, Norway..
    Volatility of electricity price in Denmark and Sweden2019Ingår i: INNOVATIVE SOLUTIONS FOR ENERGY TRANSITIONS / [ed] Yan, J Yang, HX Li, H Chen, X, ELSEVIER SCIENCE BV , 2019, s. 4331-4337Konferensbidrag (Refereegranskat)
    Abstract [en]

    Under the pressure of global environmental climate change, all countries in the world are developing renewable energy such as hydropower, wind energy, and solar energy As a result, the electricity price varies in different patterns depending on the penetration of renewable energy. In this paper, a non-parametric model is employed to analyze the historical data of electricity spot price from Danish price areas of the Nord Pool (with high percentage of wind power), Swedish price areas of the Nord Pool (with high percentage of hydropower) and PJM market (with little renewable energy penetrated). The objective is to deeply understand the influence of renewable energies on electricity price volatility. It is found that electricity prices are more stable in Swedish price areas as hydropower is a more stable energy source. The electricity price in PJM market is also comparatively stable, only more volatile than Swedish market, as fossil fuels are dominant energy resources. For Danish price areas, the volatility of electricity prices is clearly affected by wind power, which is a highly intermittent energy resource.

  • 140.
    Du, F.
    et al.
    Department of Electronic and Electric Engineering, University of Strathclyde, Glasgow, United Kingdom.
    Zhang, J.
    Department of Electronic and Electric Engineering, University of Strathclyde, Glasgow, United Kingdom.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Galloway, S.
    Department of Electronic and Electric Engineering, University of Strathclyde, Glasgow, United Kingdom.
    Lo, K. L.
    Department of Electronic and Electric Engineering, University of Strathclyde, Glasgow, United Kingdom.
    Modelling the impact of social network on energy savings2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 178, s. 56-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is noted that human behaviour changes can have a significant impact on energy consumption, however, qualitative study on such an impact is still very limited, and it is necessary to develop the corresponding mathematical models to describe how much energy savings can be achieved through human engagement. In this paper a mathematical model of human behavioural dynamic interactions on a social network is derived to calculate energy savings. This model consists of a weighted directed network with time evolving information on each node. Energy savings from the whole network is expressed as mathematical expectation from probability theory. This expected energy savings model includes both direct and indirect energy savings of individuals in the network. The savings model is obtained by network weights and modified by the decay of information. Expected energy savings are calculated for cases where individuals in the social network are treated as a single information source or multiple sources. This model is tested on a social network consisting of 40 people. The results show that the strength of relations between individuals is more important to information diffusion than the number of connections individuals have. The expected energy savings of optimally chosen node can be 25.32% more than randomly chosen nodes at the end of the second month for the case of single information source in the network, and 16.96% more than random nodes for the case of multiple information sources. This illustrates that the model presented in this paper can be used to determine which individuals will have the most influence on the social network, which in turn provides a useful guide to identify targeted customers in energy efficiency technology rollout programmes.

  • 141.
    Du, Y.
    et al.
    College of Electronics and Information Engineering, Tongji University, Shanghai, China.
    Wang, C.
    College of Electronics and Information Engineering, Tongji University, Shanghai, China.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Song, Jingjing
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, B.
    School of Mechanical Engineering, Hubei University of Arts and Science, Hubei Province, China.
    Clustering heat users based on consumption data2019Ingår i: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, s. 3196-3201Konferensbidrag (Refereegranskat)
    Abstract [en]

    In today's district heating (DH) energy market, it is common to use user functional categories in price models to determine the heat price. However, users in the same category do not necessarily have the same energy consumption patterns, which potentially leads to unfair prices and many other practical issues. Taking into account heat usage characteristics, this work proposes two data-driven methods to cluster DH users to identify similar usage patterns, using practical energy consumption data. Efforts are focused on extracting representative features of users from their daily usage profiles and duration curves, respectively. Employing clustering based on these features, the resulting typical usage patterns and user category distributions are discussed. Our results can serve as potential inputs for future energy price models, demand-side management, and load reshaping strategies.

  • 142.
    Efstathiadis, T.
    et al.
    Aristotle Univ Thessaloniki, Greece.
    Kalfas, A. I.
    Aristotle Univ Thessaloniki, Greece.
    Seferlis, P.
    Aristotle Univ Thessaloniki, Greece.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Rivarolo, M.
    Univ Genoa, Italy.
    Geometry Optimization of Power Production Turbine For A Low Enthalpy (<= 100 degrees C) ORC System2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 1624-1630Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present paper is examining the geometry optimization of a power production turbine, in the range of 100kW(el), for a low enthalpy Organic Rankine cycle system (<= 100 degrees C). In the last years, accelerated consumption of fossil fuels has caused many serious environmental problems such as global warming, ozone layer destruction and atmospheric pollution. It is this reason that a growing trend towards exploiting low-enthalpy content energy sources has commenced and led to a renewed interest in small-scale turbines for Organic Rankine Cycle applications. The design concept for such turbines can be quite different from either standard gas or steam turbine designs. The limited enthalpic content of many energy sources imposes the use of organic working media, with unusual properties for the turbine. A versatile cycle design and optimization requires the parameterization of the main turbine design. There are many potential applications of this power-generating turbine, including geothermal and concentrate solar thermal fields or waste heat of steam turbine exhausts. An integrated model of equations has been developed, thus creating a model to assess the performance of an organic cycle for various working fluids such as R134a and isobutane-isopentane mixture. The most appropriate working fluid has been chosen, taking its influence on both cycle efficiency and the specific volume ratio into consideration. This choice is of particular importance at turbine extreme operating conditions, which are strongly related to the turbine size. In order to assess the influence of various design parameters, a turbine design tool has been developed and applied to define the geometry of blades in a preliminary stage. Finally, as far as the working fluid is concerned, the mixture of 85% isopentane-15% isobutane has been chosen as the most suitable fluid for the low enthalpy ORC system, since its output net power is 10% higher compared to the output net power of R134a. 

  • 143.
    Eriksson, Douglas
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Investigation of the energy saving potential for an office building complex: A study on the viability of an on-site combined heat- and power supply system2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The building stock in the European Union accounts for over 40% of final energy use, where the usage of non-residential buildings may be up to 40% higher than the residential sector. Improving building energy efficiency across all categories of buildings is one key goal of the European energy policies, made prominent by the Climate and Energy package, Energy Performance of Building Directive (EPBD) and Energy Efficiency Directive (EED). In this study, a simulation model of an office-building complex utilizing district heating was created using transient simulation software TRNSYS. The model was validated using consumption data provided by the facility owner, after which an investigation of the energy saving potential along with the economic viability of adapting a new heat- and power supply system was conducted. The system designs were comprised of a geothermal energy system in combination with a PV-system and electricity storage. It was concluded that the systems were sufficient in maintaining an adequate indoor climate. Furthermore, the investments were ascertained as profitable and resulted in a decreased building specific energy demand.

  • 144.
    Eriksson, O.
    et al.
    Department of Building, Energy and Environmental Engineering, Faculty of Engineering and Sustainable Development, University of Gävle, Sweden.
    Hadin, Å.
    Department of Building, Energy and Environmental Engineering, Faculty of Engineering and Sustainable Development, University of Gävle, Sweden.
    Hennessy, Jay
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation. SP Technical Research Institute of Sweden, Borås, Sweden.
    Jonsson, D.
    Department of Building, Energy and Environmental Engineering, Faculty of Engineering and Sustainable Development, University of Gävle, Sweden.
    Life cycle assessment of horse manure treatment2016Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 9, nr 12, artikel-id 1011Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Horse manure consists of feces, urine, and varying amounts of various bedding materials. The management of horse manure causes environmental problems when emissions occur during the decomposition of organic material, in addition to nutrients not being recycled. The interest in horse manure undergoing anaerobic digestion and thereby producing biogas has increased with an increasing interest in biogas as a renewable fuel. This study aims to highlight the environmental impact of different treatment options for horse manure from a system perspective. The treatment methods investigated are: (1) unmanaged composting; (2) managed composting; (3) large-scale incineration in a waste-fired combined heat and power (CHP) plant; (4) drying and small-scale combustion; and (5) liquid anaerobic digestion with thermal pre-treatment. Following significant data uncertainty in the survey, the results are only indicative. No clear conclusions can be drawn regarding any preference in treatment methods, with the exception of their climate impact, for which anaerobic digestion is preferred. The overall conclusion is that more research is needed to ensure the quality of future surveys, thus an overall research effort from horse management to waste management.

  • 145.
    Eriksson, Rickard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Andersson, Pontus
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Thermal storage solutions for a building in a 4th generation district heating system: Development of a dynamic building model in Modelica2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The world is constantly striving towards a more sustainable living, where every part of contribution is greatly appreciated. When it comes to heating of buildings, district heating is often the main source of heat. During specific times, peak demands are created by the tenants who are demanding a lot of heat at the same time. This demand peak puts a high load on the piping system as well as the need for certain peak boilers that run on non-environmental friendly peak fuel. One solution that is presented in this degree project that solves the time difference between production and demand is by utilizing thermal storage solutions. A dynamic district heated building model is developed with proper heat propagation in the pipelines, thermal inertia in the building and heat losses through the walls of the building. This is all done utilizing 4th generation district heating temperatures. Modelica is the tool that was used to simulate different scenarios, where the preheating of indoor temperature is done to mitigate the possibility for demand peaks. Using an already existing model, implementation and adjustments are done to simulate thermal storage and investigate its effectiveness in a 4th generation district heating system. The results show that short-term energy storage is a viable solution in concrete buildings due to high building mass. However, combining both 4th generation district heating with storage in thermal mass is shown not to be suitable due to low temperatures of supply water, which is not able to increase the temperature of the building’s mass enough.

  • 146.
    Eriksson, Åsa
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Ny teknik för småskalig kraftvärme: - med fokus på Organisk RankineCykel (ORC)2009Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    As a part of the fight against the global warming the energy production needs to be more efficient and redirected towards sustainable options. One alternative is cogeneration, which means that electricity and heat is produced in one plant. The purpose with this survey is to examine if there are any commercial available combined heat and power techniques, based on combustion of solid moist biomass, which are suitable to small-scale applications. The technique must be able to produce between 2 and 10 MW thermal and the heat demand is a Swedish district-heating system. When already published reports had been studied, the Organic Rankine Cycle (ORC) was chosen as the most suitable technique. The possibility of using the ORC to generate electricity from the district-heating return flow was considered simultaneously. The chosen ORC-technique was then evaluated in Excel. The first aspect to be examined was how the performance of a combined heat and power plant was affected by variations in the supply line temperature. It showed that the performance reaches top levels when the temperature is low. The second part contains an optimisation, in a techno-economical perspective, of the ratio between cogeneration and separate heat production for district-heating systems with heat demands below 50 GWh/year. The most profitable combined heat and power plant generates 45 % of the installed power in a 50 GWh system. The profit is, however, too low to justify any construction plans. The conclusion was that there are no economical reasons to choose combined heat and power based on an organic rankine cycle in Sweden today.

  • 147.
    Erneby, Robin
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    KORTSIKTIG PRODUKTIONSPLANERING I MINDRE FJÄRRVÄRMESYSTEM: En studie vid Strängnäs Energi AB2012Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    District heating covers around 80 % of the heating demand in apartment buildings and 10 % in single-family homes in Sweden. In the year 2010 the total input of energy to the Swedish district heating grids was about 70 TWh, which corresponds to 11 % of the total energy input to the whole energy system in the country. Through the combined production of heat and power the CHP-plants often reaches an efficiency of 90 % from energy in the fuel to produced heat and power. In order to keep the efficiency high it is important for the owners of the plant to have good knowledge about the plants performance at different operation points. Strängnäs Energi AB initiated this diploma work together with FVB Sverige ab in order to come up with a program for short term planning of the production of heat and power at the company´s CHP-plant.

    The work consists of three main parts. The first part is an introduction to district heating and optimization of such systems and it also handles a short explanation of the district heating system in Strängnäs.

    The second part covers the performance tests that have been done at Strängnäs Energi AB´s CHP-plant. The performance tests were carried out in order to investigate how the plant is operating. The results from the tests show that the efficiency of the plant is very poor. This has its explanation in the losses in forms of combustible content in the bottom ash, which in some cases reaches over 4 %. The problems with the combustion have been known for a while at Strängnäs Energi AB, but they did not have any calculated value of the efficiency. The company is working hard in order to come up with good solutions for the combustion and therefore this is not included in the diploma work. Instead the third part of the diploma work is focused on developing of a model for short term production planning. The model was made in MS Excel and it consists of a number of power and mass balances over one day. The key to the calculations in the model is the calculation of the alfa-value. The alfa-value together with the power in the hot water condenser gives an iterative calculation. The hot water accumulator is then either charged or discharged depending on current electrical price, demand of district heating and the level in the accumulator. The results from the simulations done with the model shows that it is possible for Strängnäs Energi AB to earn between 0 – 20 000 SEK during one day if they operate their plant as suggested in the model.

  • 148.
    Eskilsson, Anton
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Energy flow mapping of a sports facility: Energy flow mapping and suitable key performance indicator formulation for Rocklunda sports facility2017Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 149.
    Feng, J. -C
    et al.
    School of Engineering, Sun Yat-Sen University, Guangzhou, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Chemical Science and Engineering, Royal Institute of Technology, Teknikringen 42, Stockholm, Sweden.
    Yu, Z.
    School of Engineering, Sun Yat-Sen University, Guangzhou, China.
    Zeng, X.
    School of Engineering, Sun Yat-Sen University, Guangzhou, China.
    Xu, W.
    School of Engineering, Sun Yat-Sen University, Guangzhou, China.
    Case study of an industrial park toward zero carbon emission2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 209, s. 65-78Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industrial park shoulders heavy responsibilities for economic development, and in the meantime, acts the role as energy consumer and carbon emitter. Under the background of holding the average global temperature increase limited in 2 °C compared to the pre-industrial level, which was proposed in the Paris Agreement, the development of zero carbon emission at the industrial park level is of great importance. This study investigated how to realize zero carbon emission at an industrial park level. In addition, a practical case study of the Southern China Traditional Chinese Medicine Industrial Park located in the Zhongshan City, Guangdong Province of China was conducted. Scenario analyses were projected to realize zero carbon emission in this industrial park and the results show that zero carbon emission can be realized under all the three scenarios. Economic assessments found that purchasing carbon offsets get the minimum cost effectiveness under current market situation. However, purchasing carbon offset may not be the best choice from the aspect of absolute reduction. Sensitivity analyses illustrate that the cost effectiveness of carbon reduction is remarkably influenced by the carbon price and solar energy cost reduction ratio. Meanwhile, applying large-scale renewable energy and producing more carbon offset can harvest more economic and carbon reduction benefits when the current solar energy cost has been reduced by 90%. Moreover, challenges of building zero-carbon industrial park as well as the corresponding solution schemes were discussed.

  • 150.
    Fiedler, Frank
    Dalarna University College, Sweden.
    The state of the art of small-scale pellet-based heating systems and relevant regulations in Sweden, Austria and Germany2004Ingår i: Renewable and Sustainable Energy Reviews, ISSN 1364-0321, Vol. 8, nr 3, s. 201-221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The emphasis of this report is on the actual technology of small-scale pellet combustion units and important regulations concerning emissions and pellets. Wood as a heating source has a long tradition in Sweden, but the use of compressed wood pellets in domestic stoves and boilers is rather new. Based on a literature survey, information from manufacturers and test institutes, this report gives an overview about existing technology and investigates how mature it is already. Some comparisons were made to similar heating units in Austria, where this technique is also widely used. It could be seen that the Austrian boilers are more sophisticated including a high level of comfort for the user. On the other hand the simpler Swedish boilers are significantly less expensive, and it is questionable if Swedish costumers are willing to pay for the higher comfort. Relevant regulations concerning emissions and fuel quality are also reported and compared between Sweden, Germany and Austria. In addition some interesting non-official certificates and environmental labels are presented. These give an outlook to future, probably more stringent, regulations.

1234567 101 - 150 av 723
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf