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  • 301.
    Kovala, Tommy
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    This electricity price is too high for my household: Why are some households sensitive to the electricity price, when others barely are sensitive at all?2017Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The key-solution for a sustainable electricity system is demand flexibility. If we use technology to distribute the information, demand flexibility could be incentivized by dynamic pricing, so that real problems and costs in the electricity system become transparent for electricity consumers.

    Utilities and electricity retailers have tried to offer such contracts before, but deemed the necessary educative interventions for consumers too expensive and retreated to nominal price competition (Flaim et al., 2013). Using a questionnaire, collecting intentions for demand flexibility, we reveal that lacking knowledge is just one of many areas that could be targeted with interventions.

  • 302.
    Kovala, Tommy
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Hallin, Anette
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Industriell ekonomi och organisation.
    Factors influencing industrial excess heat collaborations2016Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 88, s. 595-599Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In Sweden there is a potential to double the amount of industrial excess heat from todays 5 TWh that is delivered into district heating networks. This paper investigates factors that are influencing industrial excess heat collaborations. The paper presents result from qualitative interviews as well as answers through a more quantitative web based survey which has been sent out to stakeholders in existing Swedish industrial excess heat collaborations. This work provides new evidence on that economic motivations are the most common driver for starting up a collaboration, but well in place factors like transparency as well as investment sharing between the partners becomes important for a long-term successful collaboration.

  • 303.
    Krustok, Ivo
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Communities of microalgae and bacteria in photobioreactors treating municipal wastewater2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Everyone who uses water produces wastewater. This inevitability creates several problems that increase with the growth of the population and industry. What to do with the wastewater, how to purify it and how to design the infrastructure are all important questions that each municipality has to deal with, taking into account ever growing demands to reduce environmental impact. In these conditions scientists and engineers have turned to biological processes to help treat the water. Currently the most commonly used wastewater treatment method known as the activated sludge process involves bacteria that help break down the pollutants. While it has been used successfully for around 100 years now, it has many limitations when faced with modern demands. As an alternative, microalgae reactors, commonly known as photobioreactors, have been suggested.

    Microalgae are microscopic water organisms that can use photosynthesis to form sugars from CO2 and water. To do this they require energy from light, hence the photo part of the photobioreactor. In addition to taking up CO2 from their environment, they take up nutrients such as nitrogen and phosphorous compounds. This is a reason why microalgae have great potential for use in wastewater treatment. When grown in wastewater together with the microorganisms already present, they are able to reduce the amount of pollutants by taking them up into their cells, effectively purifying the water.

    Since wastewater has its own microbial community, the biological processes taking place in a wastewater treating photobioreactor are more complex compared to growing a single species of algae in a sterile medium. With the work presented in this licentiate, we characterized the algae and bacterial communities present in photobioreactors treating wastewater in addition to finding the most optimal ways to grow algae originating from a local lake in a wastewater medium. We looked at the species found, most important metabolic pathways, growth dynamics for both algae and bacteria and water purification dynamics.

    Overall, we were successful in inoculating municipal wastewater from Västerås wastewater treatment plant with algae from Lake Mälaren. The dominant algae growing in our systems belonged to the genera Scenedesmus, Desmodesmus and Chlorella. We also saw that the bacterial community was involved in synthesis of vitamins essential for algae growth. The information presented in this thesis is another step towards a better design of control and monitoring systems in full-scale photobioreactor plants.

  • 304.
    Krustok, Ivo
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Microbiological analysis of municipal wastewater treating photobioreactors2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    I takt med att världens befolkning ökar, så produceras dagligen allt mer avfall. Detta kan orsaka stora problem för miljön. När det byggs nya system för vattenrening behöver vi även ta hänsyn till kravet att minska energiåtgången. Dagens vattenreningssystem har vissa tillkortakommanden när det gäller reningsnivåer och energianvändning. Ett alternativ till dagens system, kan vara fotobioreaktorer, dvs. vattenrening med hjälp av mikroalger. Dessa system använder mikroalger och bakterier för att rena vattnet från föroreningar, kväve och fosfor.

    Vattenrening med fotobioreaktorer är en relativt ny teknik. Flera aspekter gällande biologin i dessa system har ännu inte studerats i detalj. Den här avhandlingen presenterar en översikt av de alger och bakterier som är aktiva i fotobioreaktorer. Andra viktiga aspekter som tillväxt, arter samt vattenreningsförmåga har också studerats.

    Ett antal försök genomfördes där alger från Mälaren tillsattes i vatten från Västerås kommunala vattenreningsanläggning. Storleken på försöken varierade mellan 250 ml och 20 liter. Det visade sig att algerna hade en bra tillväxt samt att mängden ammonium och fosfor minskade i vattnet under försöksperioden.

    De alger som tillväxte mest i studien tillhörde Scenedesmus, Desmodesmus och Chlorella. Förutom alger tillväxte även ett stort antal bakterier från grupperna Proteobacteria and Bacteroidetes. Dessa bakterier visade sig syntetisera viktiga vitaminer, t.ex. vitamin B12, som algerna normalt inte kan syntetisera själva.

    Sammanfattningsvis, så presenterar denna avhandling viktig information gällande alger och bakterier i en fotobioreaktor. Informationen kan vara ett viktigt bidrag till framtida utveckling av storskaliga fotobioreaktorer för vattenrening.

  • 305.
    Krustok, Ivo
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Diaz, J G
    Faculty of Science, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid, Spain.
    Odlare, Monica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Algae biomass cultivation in nitrogen rich biogas digestate.2015Ingår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 72, nr 10, s. 1723-1729Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Because microalgae are known for quick biomass growth and nutrient uptake, there has been much interest in their use in research on wastewater treatment methods. While many studies have concentrated on the algal treatment of wastewaters with low to medium ammonium concentrations, there are several liquid waste streams with high ammonium concentrations that microalgae could potentially treat. The aim of this paper was to test ammonium tolerance of the indigenous algae community of Lake Malaren and to use this mixed consortia of algae to remove nutrients from biogas digestate. Algae from Lake Malaren were cultivated in Jaworski's Medium containing a range of ammonium concentrations and the resulting algal growth was determined. The algae were able to grow at NH4-N concentrations of up to 200 mg L(-1) after which there was significant inhibition. To test the effectiveness of the lake water algae on the treatment of biogas digestate, different pre-cultivation set-ups and biogas digestate concentrations were tested. It was determined that mixing pre-cultivated suspension algae with 25% of biogas digestate by volume, resulting in an ammonium concentration of around 300 mg L(-1), produced the highest algal growth. The algae were effective in removing 72.8 ± 2.2% of NH4-N and 41.4 ± 41.4% of PO4-P.

  • 306.
    Krustok, Ivo
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Diaz, Juan Guillermo
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Shabiimam, MA
    Indian Institute of Technology, Bombay, India.
    ALGAE BIOMASS CULTIVATION WITH AMMONIUM RICH WASTEWATERS AS SUBSTRATE: THE POTENTIAL FOR SIMULTANEOUS WASTEWATER TREATMENT AND ENERGY RECOVERY2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ammonia rich wastewaters pose risk to recipient waters and the atmosphere, and can be difficult to treat in wastewater treatment plants (WTTP) due to toxicity to the microbes in conventional biological treatment systems. This article presents an idea on how to use a combination of bacteria and microalgae for efficient treatment of wastewaters with high ammonia concentrations (200-1400 mg/L). The challenge in this research is that most algae species are sensitive to high ammonia concentrations (>1 mM)(Abalde and Mezzamo, 2009). Despite the numerous wastewaters that contain high ammonia concentrations, i.e. landfill leachate, piggery manure, reject water and biogas digestate, the progress in finding sustainable treatment methods is taking time. This despite the fact that climate change, eutrophication and eco-toxicity is negatively affected by this commonly occurring component. Further, nitrogen is a valuable nutrient that in conventional WWTP is just released into the air without any recycling or recovery.

    In this article, we present a study where algae were cultivated as a mean for treatment of wastewater reject water and swine manure from a piggery farm. The algae inoculum was pretreated from lake water, sampled in mid Sweden during summer algae blooms. Lake Mälaren is a shallow lake with a rich algae consortia, optimized for the local climate. During seasonal algae blooms, the lake demonstrates the extremely rapid growth rate of the algae such as cyanobacteria, green algae and diatoms. Algae inoculum, wastewater substrate and dilution media (tap water) were mixed in various ranges of ammonium concentrations to evaluate the nutrient removal and algae biomass growth. During the algae cultivation experiment, chlorophyll, optical density and TS were used as indicators for algae biomass growth. Flow Injection System (FIA) was used for nutrient analysis.

    The two main findings in this research are that algae growth is inhibited by ammonia but that it is possible to grow algae in readily high ammonia concentrations. Moreover, significant amount of ammonium were removed by algae during the cultivation in the reactors.

  • 307.
    Krustok, Ivo
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Odlare, Monica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    M.A., Shabiimam
    Indian Institute of Technology, Bombay, India..
    Truu, Jaak
    University of Tartu, Estonia.
    Ligi, Teele
    University of Tartu, Estonia.
    Truu, Marika
    University of Tartu, Estonia.
    Characterization of algal and microbial community dynamics in a wastewater photo-bioreactor using indigenous algae from lake mälaren2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Microalgae grown in photo-bioreactors can be a valuable source for biomass especially when combined with the treatment of wastewater. While most published research has been studying pure cultures, consortia of algae and bacteria from the wastewater have more complex dynamics affecting both the biomass production and pollutant removal. In this paper we investigate dynamics of algal and bacterial communities in mixed culture photo-bioreactors using chlorophyll and real-time PCR analysis. Wastewater photo-bioreactors were inoculated with water from a nearby lake to add native algae species. The results indicated a decline in bacterial 16S rDNA copy numbers before algae started to multiply. The photo-bioreactors inoculated with lake algae produced more biomass and grew faster than the algae originating only from wastewater. The reactors were effective in removing ammonia from the wastewater which seemed work to mostly through nitrification thus causing an increase in nitrate concentration. There was also an increase in Cr, Co and Ni ion concentrations during the experiment suggesting they may have moved from organic complexes to the water phase as free ions.

  • 308.
    Krustok, Ivo
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Odlare, Monica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    M.A., Shabiimam
    Indian Institute of Technology, Bombay, India..
    Truu, Jaak
    University of Tartu, Estonia.
    Truu, Marika
    University of Tartu, Estonia.
    Ligi, Teele
    University of Tartu, Estonia.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Characterization of algal and microbial community growth in a wastewater treating batch photo-bioreactor inoculated with lake water2015Ingår i: Algal Research, ISSN 2211-9264, Vol. 11, nr Sept, s. 421-427Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Microalgae grown in photo-bioreactors can be a valuable source of biomass, especially when combined with wastewater treatment. While most published research has studied pure cultures, the consortia of algae and bacteria from wastewater have more complex community dynamics which affect both the biomass production and pollutant removal. In this paper we investigate the dynamics of algal and bacterial growth in wastewater treating batch photo-bioreactors. The photo-bioreactors were inoculated with water from a nearby lake. Lake water was obtained in August, November and December in order to add native algal species and study the effects of the season. The photo-bioreactors inoculated with lake water obtained in August and November produced more biomass and grew faster than those that only contained the algae from wastewater. The results indicated a rapid decline in bacterial abundance before algae began to multiply in reactors supplemented with lake water in November and December. The reactors were also successful in removing nitrogen and phosphorous from wastewater.

  • 309.
    Krustok, Ivo
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Odlare, Monica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Truu, Jaak
    University of Tartu, Estonia.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Inhibition of nitrification in municipal wastewater treating photobioreactors: effect on algal growth and nutrient uptake2016Ingår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 202, s. 238-243Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of inhibiting nitrification on algal growth and nutrient uptake was studied in photobioreactors treating municipal wastewater. As previous studies have indicated that algae prefer certain nitrogen species to others, and because nitrifying bacteria are inhibited by microalgae, it is important to shed more light on these interactions. In this study allylthiourea (ATU) was used to inhibit nitrification in wastewater-treating photobioreactors. The nitrification-inhibited reactors were compared to control reactors with no ATU added.

    Microalgae had higher growth in the inhibited reactors, resulting in a higher chlorophyll a concentration. The species mix also differed, with Chlorella and Scenedesmus being the dominant genera in the control reactors and Cryptomonas and Chlorella dominating in the inhibited reactors. The nitrogen speciation in the reactors after 8 days incubation was also different in the two setups, with N existing mostly as NH4-N in the inhibited reactors and as NO3-N in the control reactors.

  • 310.
    Krustok, Ivo
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Odlare, Monica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Truu, Marika
    University of Tartu, Estonia.
    Truu, Jaak
    University of Tartu, Estonia.
    Ligi, Teele
    University of Tartu, Estonia.
    Tiirik, Kertu
    University of Tartu, Estonia.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Effect of lake water on algal biomass and microbial community structure in municipal wastewater based lab-scale photobioreactors2015Ingår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 99, nr 21, s. 6537-6549Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photobioreactors are a novel environmental technology that can produce biofuels with the simultaneous removal of nutrients and pollutants from wastewaters. The aim of this study was to evaluate the effect of the lake water addition to the production of algal biomass, and phylogenetic and functional structure of the algal and bacterial communities in the lab-scale bioreactors treating municipal wastewater.

    The lake water addition has significant benefit to the overall algal biomass growth and nutrient reduction in the reactors with wastewater and lake water (ratio 70/30 v/v). The metagenome based survey showed that the most abundant algal phylum in these reactors was Chlorophyta with Scenedesmus being the most prominent genus. The most abundant bacterial phyla were Proteobacteria and Bacteroidetes with most dominant families being Sphingobacteriaceae, Cytophagaceae, Flavobacteriaceae, Comamonadaceae, Planctomycetaceae, Nocardiaceae and Nostocaceae. These photobioreactors were also effective in reducing the overall amount of pathogens in wastewater compared to reactors with wastewater/tap water mixture. Functional analysis of the photobioreactor metagenomes revealed an increase in relative abundance genes related to photosynthesis, synthesis of vitamins important for auxotrophic algae, and decrease in virulence and nitrogen metabolism subsystems in lake water reactors.

  • 311.
    Krustok, Ivo
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Oopkaup, Kristjan
    University of Tartu, Estonia.
    Truu, Jaak
    University of Tartu, Estonia.
    Odlare, Monica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Comparative analysis of the metagenomes extracted from wastewater treating photobioreactorsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The metagenomes of lab-scale municipal wastewater treating batch photobioreactors were studied with a focus on nitrogen metabolism, pathogen abundance and antibiotic resistance genes. Previous studies based on the dataset showed that in general, as algae growth in the reactors increased, nitrogen metabolism and virulence genes decreased. With this study, a more detailed view of these gene groups is presented.

  • 312.
    Kullman, M.
    et al.
    Eskilstuna Strängnäs Energy and Environment, Stockholm, Sweden.
    Campillo, Javier
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Fertner, C.
    University of Copenhagen, Department of Geosciences and Natural Resource Management, Copenhagen, Denmark.
    Giffinger, R.
    Vienna University of Technology, Department of Spatial Planning, Vienna, Austria.
    Grosse, J.
    University of Copenhagen, Department of Geosciences and Natural Resource Management, Copenhagen, Denmark.
    Groth, N. B.
    University of Copenhagen, Department of Geosciences and Natural Resource Management, Copenhagen, Denmark.
    Haindlmaier, G.
    Vienna University of Technology, Department of Spatial Planning, Vienna, Austria.
    Kunnasvirta, A.
    Turku University of Applied Sciences, Environment and Business, Turku, Finland.
    Strohmayer, F.
    Vienna University of Technology, Department of Spatial Planning, Vienna, Austria.
    Haselberger, J.
    Hamburg University of Applied Sciences, Hamburg, Germany.
    Note: The PLEEC project–planning for energy efficient cities2016Ingår i: Journal of Settlements and Spatial Planning, ISSN 2069-3419, Vol. 2016, nr Special Issue: 5, s. 89-92Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Globally, more than 50% of all people are living in cities today. Enhancing sustainability and efficiency of urban energy systems is thus of high priority for global sustainable development. The European research project PLEEC (Planning for Energy Efficient Cities) focuses on technological, innovative, behavioural and structural capacities of European medium-sized cities in their transition towards Energy Smart Cities. The variation of strengths and weaknesses of cities’ capabilities as well as practices and tools for enhancing energy efficient performance of urban energy systems were at the centre of the project. This short note summarises its main findings.

  • 313.
    Kumm, Maria
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Ingason, Haukur
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. SP Tech Res Inst Sweden, Boras, Sweden.
    Entrainment in a free jet generated by Positive Pressure Ventilator2014Ingår i: Fire technology, ISSN 0015-2684, E-ISSN 1572-8099, nr 6, s. 1499-1515Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Results of a simple flow model to describe the entrainment into the air cone created by a positive pressure ventilator (PPV) fan are compared to experimental data. Velocity profiles measured in the air cone of a conventional PPV ventilator are used. The entrainment coefficient and the cone angle were determined for the fan investigated. The correspondence between calculated and measured values is discussed and disparities explained. The findings from the tests are turned into practical guidance for the fire brigade and the advantages and limitations of the simplified model are discussed.

  • 314.
    Kumm, Mia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lönnermark, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. SP Sveriges Tekniska Forskningsinstitut.
    Zakirov, Artur
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Indikatorer för att bedöma räddningstjänstens insatsförmåga: -med hänsyn till de lokala förhållandena2013Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    I det inledande stycket i Lagen om skydd mot olyckor (2003:778) står att bestämmelserna i lagstiftningen syftar till att bereda människors liv och hälsa samt egendom och miljö ett med hänsyn till de lokala förhållandena tillfredsställande och likvärdigt skydd mot olyckor. Denna rapport ger en översiktlig bild av lagstiftarens intentioner och fokuserar på faktorer som är avgörande för att kunna identifiera jämförbara kommuner och indikatorer för att bedöma om deras förmåga att genomföra räddningsinsatser är likvärdig. Indikatorerna har tagits fram för att senare kunna användas i ett utvecklat metodstöd för länsstyrelserna vid bedömningar av förändringar i de kommunala programmen för skydd mot olyckor.

    Projektet har utförts på uppdrag av Tillsynsenheten vid Myndigheten för samhällsskydd och beredskap.

  • 315.
    Kumm, Mia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Palm, Anders
    Greater Stockholm Fire Brigade, Sweden.
    Rescue Operations in Underground Mass Transport Systems at Fires and Deliberate Attacks2012Ingår i: Proceedings from the Fifth Iternational Symposium on Tunnel Safety and Security, New york, USA, March 14-16, 2012 / [ed] Anders Lönnermark and Haukur Ingason, Borås: SP Technical Research Institute of Sweden , 2012, s. 223-232Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fire and rescue operations in mass transport systems underground often constitute a great challengefor the first responders. In rush-hour traffic at important junctions thousands of people can be locatedat a relatively small area. At underground fires or deliberate attacks in these premises the need forassistance or rescue can be extensive and the possibilities to reach those in distress are limited. In caseof deliberate attacks with explosives the risk for a second delayed attack, aimed at the first responders,has to be considered. The blast load and structural response can destroy important functions, used forevacuation, in the metro carriage and harm passengers in the exposed and adjacent carriages. This canincrease the need for assistance from the fire and rescue services. In this paper the possibilities for thefirst responders to assist and rescue persons at the event of fire or explosion in a tunnel is discussed,based on the research results from the full scale tests performed within the METRO-project.

  • 316.
    Kumm, Mia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Palm, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Storstockholms brandförsvar .
    Palmkvist, Krister
    Södra Älvsborgs Räddningstjänstförbund.
    Lönnermark, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Ingason, Haukur
    SP Sveriges Tekniska Forskningsinstitut.
    Räddningsinsats i tunnelmiljö: Fullskaleförsök i Tistbrottet, Sala2014Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    I oktober 2013 genomfördes sex fullskaliga brandförsök med kombinerat förflyttnings och släckmoment i Björka Minerals dolomitgruva i Tisbrottet i Sala. Tidigare har dessa två moment inte kombinerats under kontrollerade former där mätningar och observationer dokumenterats i så omfattande grad som i denna försöksserie. Rökdykarnas uppgift vid samtliga av försöken var att avancera in i tunneln och släcka branden. De sex olika försöken utgjordes av konventionell slangutläggning med slangkorgar respektive bärsele, utlägg med tomt system fram till brandplatsen, CAFS, skärsläckare och konventionell slangutläggning med hjälp av materielvagn och depåluft. Försöken visade att konventionell slangutläggning tar lång tid i anspråk, men att utlägg med tomt system och bärsele kan korta tiderna och minska belastningen. Försöken visade också att system med lägre vattenflöden hade möjligheter att slå ner branden, men att mängden vatten var avgörande för att undvika återantändning. Värmekameror är generellt inte anpassade för tunnelmiljöer och ett stort behov finns för vidare utveckling av både utrustning och utbildningsmaterial.

  • 317.
    Kumm, Mia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Palmkvist, Krister
    Södra Älvsborgs Räddningstjänstförbund, Sweden.
    Palm, Anders
    Storstockholms brandförsvar, Sweden.
    Värmekamera vid brand under mark: Ett utbildningsmaterial för räddningstjänsten2014Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Rapporten är framtagen inom ramen för det MSB-finansierade projektet TMU – Taktik och metodik vid brand under mark – och avsedd att användas som ett utbildningsmaterial för räddningstjänsten. Utbildningsmaterialet förutsätter viss grundläggande kunskap om användning av värmekamera vid brand, men kräver ingen tidigare erfarenhet av användning i undermarksmiljö. Rapporten innehåller såväl teoretiska delar som praktiska övningsexempel. Områden som behandlas är användning vid orientering och förflyttning, bedömning av brand, brandgasspridning och värmetransport samt riskbedömning för rökdykarens säkerhet.

  • 318.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    An Approach to Multi-Disciplinary Aero Engine Conceptual Design2017Konferensbidrag (Refereegranskat)
    Abstract [en]

     Various aspects of a multi-disciplinary aero engine conceptual design approach and computational framework are presented. The approach closely integrates different disciplines and is capable of homing in on the best designs in the presence of techno-economic and environmental risk. The framework can assist in the transition from the traditional, human-centered design procedure that involves complex manual iterations, to a more automated process. It considers the following disciplines: engine performance, engine aerodynamic and mechanical design, aircraft design and aerodynamic performance, emissions prediction and environmental impact, engine and airframe noise, and production, maintenance and direct operating costs. The proposed explicit conceptual design algorithm reduces system complexity, improves computational speed and can make design space exploration and optimisation results easier to interpret. Through a good set of constraints, it will also give an optimal aero engine conceptual design that may prove feasible in terms of major engine certification and customer requirements. The power of the proposed conceptual design approach has been demonstrated through a variety of unique case studies. These range from technology assessment and design sensitivity analysis to design space exploration and optimization. Overall, the work sets the necessary base for an assessment methodology that can quantify risks and assess the impact of gas turbine design on the environment, by comparing and helping to rank future technologies and design concepts for civil aviation on a formal and consistent basis.

  • 319.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University.
    Camilleri, William
    Cranfield University, Cranfield, UK.
    Gas Turbines for Power and Propulsion2015Ingår i: Handbook of Clean Energy Systems: Volume 2 - Clean Energy Conversion Technologies / [ed] Jinyue Yan, Chichester, West Sussex, UK: John Wiley & Sons, 2015, 1, s. 1-25Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    For over seven decades, the gas turbine has been used successfully in a variety of applications including aircraft, ship, and surface vehicle propulsion as well as for electrical power and heat generation. The gas turbine is in essence a type of internal combustion engine comprising in its simplest form a compressor, a combustor, and a turbine. It can utilize a variety of different fuels, most commonly natural gas and kerosene (Jet-A).

    The gas turbine has played a key role in the expansion of jet transportation and is currently the prime mover for almost all commercial applications, other than light aircraft. It also has had a considerable impact in the power generation sector with efficiencies in excess of 40% for simple cycles, and close to 60% for combined cycles. Over the next decades, it is expected that the gas turbine will continue to play a significant role in the power generation and propulsion market.

    This article covers the fundamentals of gas turbine design, performance, and future technology development. First, a short presentation of the fundamental thermodynamics relating to the gas turbine is given. It is followed by an ideal analysis of three major cycles: the simple cycle, the intercooled cycle, and the intercooled recuperated cycle. Typical losses for gas turbine components are discussed along with relevant performance modeling methods. The fundamental principles of gas turbine conceptual design are presented followed by an assessment of the real performance of the three major cycles. Finally, a critical review is presented of future gas turbine concepts and their enabling technologies, with the primary focus on civil aircraft propulsion. Recent development trends and the primary research and development efforts by major gas turbine manufacturers are discussed in detail.

  • 320.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University, UK.
    On Gas Turbine Conceptual Design2019Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    The thesis begins with a review of the evolution of the industry's vision for the aero-engine design of the future. Appropriate research questions are set that can influence how this vision may further evolve in the years to come. Design constraints, material technology, customer requirements, noise and emissions legislation, technology risk and economic considerations and their effect on optimal concept selection are discussed in detail. Different aspects of the pedagogy of gas turbine conceptual design as well as information on the Swedish and Brazilian educational systems are also presented.

    A multi-disciplinary aero-engine conceptual design tool is utilised for assessing engine/aircraft environmental performance. The tool considers a variety of disciplines that span conceptual design including: engine performance, engine aerodynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, and production, maintenance and direct operating costs.

    With respect to addressing the research questions set, several novel engine cycles and technologies - currently under research - are identified. It is shown that there is great potential to reduce fuel consumption for the different concepts identified, and consequently decrease the CO2 emissions. Furthermore, this can be achieved with sufficient margin from the NOx certification limits set by International Civil Aviation Organisation, and in line with the medium-term and long-term goals set through it's Committee on Aviation Environmental Protection.

    The option of an intercooled-core geared-fan aero-engine for long-haul applications is assessed by means of a detailed design space exploration. An attempt is made to identify the fuel burn optimal values for a set of engine design parameters by varying them all simultaneously, as well as in isolation. Different fuel optimal designs are developed based on different sets of assumptions. Evidence is provided that higher overall pressure ratio intercooled engine cycles become more attractive in aircraft applications that require larger engine sizes.

    The trade-off between the ever-increasing energy efficiency of modern aero-engines and their NOx performance is assessed. Improving engine thermal efficiency has a detrimental effect on NOx emissions for traditional combustors, both at high altitude and particularly at sea-level conditions. Lean-combustion technology does not demonstrate such behaviour and can therefore help decouple NOx emissions performance from engine thermal efficiency. If we are to reduce the contribution of aviation to global warming, however, future certification legislation may need to become more stringent and comprehensive, i.e., cover high altitude conditions. By doing so we can help unlock the competitive advantage of lean burn technology in relation to cruise NOx and mission performance.

    Finally, some insight is provided on the potential benefits to be tapped from a transition from the traditional deterministic approach for system analysis to a stochastic (robust design) approach for economic decision-making under uncertainty. A basic methodology is outlined and applied on a specific conceptual design case for a conventional turbofan engine. The sensitivity of an optimal engine design obtained deterministically to real-life uncertainties is found to be far from negligible. The considerable impact of production scatter, measurement uncertainties as well as component performance deterioration, on engine performance must be catered for; this includes taking into consideration control system design aspects. A fast analytical approach is shown to be sufficiently accurate for the conceptual design process, particularly for estimating key performance parameters. These relate to type-test certication and performance retention guarantees including preliminary estimates of engine production margins.

    Lessons learned are presented from: (i) the integration of different elements of conceptual design in a new BSc course and an existing traditional MSc course on gas turbine technology, (ii) the development of an intensive course on gas turbine multi-disciplinary conceptual design. The results from the use of problem-based learning are very encouraging, in terms of enhancing student learning and developing engineering skills.

  • 321.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    On Intercooled Turbofan Engines2013Ingår i: PROGRESS IN GAS TURBINE PERFORMANCE / [ed] Benini, E, INTECH, 2013, s. 3-24Kapitel i bok, del av antologi (Refereegranskat)
  • 322.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    On the trade-off between aviation NOx and energy efficiency2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 185, s. 1506-1516Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study aims to assess the trade-off between the ever-increasing energy efficiency of modern aero-engines and their   performance. The work builds on performance models previously developed to optimise the specific fuel consumption of future aero-engine designs. As part of the present work a simple and adaptable   emissions correlation for Rich-burn Quick-quench Lean-burn combustor designs is derived. The proposed model is computationally inexpensive and sufficiently accurate for use in aero-engine multi-disciplinary conceptual design tools. Furthermore, it is possible to adapt the correlation to model the   emissions of combustors designed for very aggressive future cycles. An approach to lean-burn combustor   emissions modelling is also presented. The simulation results show that improving engine propulsive efficiency is likely to have a benign effect on  emissions at high altitude; at sea-level conditions   emissions are particularly likely to reduce. Improving engine thermal efficiency however has a detrimental effect on   emissions from RQL combustors, both at high altitude and particularly at sea-level conditions. LDI combustor technology does not demonstrate such behaviour. Current legislation permits trading   emissions engine efficiency and hence reduce   emissions. If we are to reduce the contribution of aviation to global warming, however, future certification legislation may need to become more stringent and comprehensive.

  • 323.
    Kyprianidis, Konstantinos G.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University.
    Future Aero Engine Designs: An Evolving Vision2011Ingår i: Advances in Gas Turbine Technology / [ed] Ernesto Benini, Rijeka, Croatia: InTech, 2011, 1st, s. 3-24Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 324.
    Kyprianidis, Konstantinos G.
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University.
    Sethi, Vishal
    Cranfield University.
    Ogaji, Stephen O. T.
    Cranfield University.
    Pilidis, Pericles
    Cranfield University.
    Singh, Riti
    Cranfield University.
    Kalfas, Anestis I.
    Aristotle University of Thessaloniki.
    Thermo-Fluid Modelling for Gas Turbines-Part I: Theoretical Foundation and Uncertainty Analysis2009Ingår i: ASME TURBO EXPO 2009 Proceedings, GT2009-60092, 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this two-part publication, various aspects of thermo-fluidmodelling for gas turbines are described and their impact onperformance calculations and emissions predictions at aircraftsystem level is assessed. Accurate and reliable fluid modellingis essential for any gas turbine performance simulation softwareas it provides a robust foundation for building advanced multidisciplinarymodelling capabilities. Caloric properties forgeneric and semi-generic gas turbine performance simulationcodes can be calculated at various levels of fidelity; selection ofthe fidelity level is dependent upon the objectives of thesimulation and execution time constraints. However, rigorousfluid modelling may not necessarily improve performancesimulation accuracy unless all modelling assumptions andsources of uncertainty are aligned to the same level. Certainmodelling aspects such as the introduction of chemical kinetics,and dissociation effects, may reduce computational speed andthis is of significant importance for radical space explorationand novel propulsion cycle assessment.

    This paper describes and compares fluid models, based ondifferent levels of fidelity, which have been developed for anindustry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles.The latter comprises the following modules: engineperformance, aircraft performance, emissions prediction, andenvironmental impact. The work presented aims to fill thecurrent literature gap by: (i) investigating the commonassumptions made in thermo-fluid modelling for gas turbinesand their effect on caloric properties and (ii) assessing theimpact of uncertainties on performance calculations andemissions predictions at aircraft system level.

    In Part I of this two-part publication, a comprehensiveanalysis of thermo-fluid modelling for gas turbines is presentedand the fluid models developed are discussed in detail.Common technical models, used for calculating caloricproperties, are compared while typical assumptions made influid modelling, and the uncertainties induced, are examined.Several analyses, which demonstrate the effects of composition,temperature and pressure on caloric properties of workingmediums for gas turbines, are presented. The working mediumsexamined include dry air and combustion products for variousfuels and H/C ratios. The errors induced by ignoringdissociation effects are also discussed.

  • 325.
    Kyprianidis, Konstantinos G.
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University.
    Sethi, Vishal
    Cranfield University.
    Ogaji, Stephen O. T.
    Cranfield University.
    Pilidis, Pericles
    Cranfield University.
    Singh, Riti
    Cranfield University.
    Kalfas, Anestis I.
    Aristotle University of Thessaloniki.
    Thermo-Fluid Modelling for Gas Turbines-Part II: Impact on Performance Calculations and Emissions Predictions at Aircraft System Level2009Ingår i: ASME TURBO EXPO 2009 Proceedings, GT-2009-60101, 2009, s. 483-494Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this two-part publication, various aspects of thermo-fluidmodelling for gas turbines are described and their impact onperformance calculations and emissions predictions at aircraftsystem level is assessed. Accurate and reliable fluid modellingis essential for any gas turbine performance simulation softwareas it provides a robust foundation for building advanced multidisciplinarymodelling capabilities. Caloric properties forgeneric and semi-generic gas turbine performance simulationcodes can be calculated at various levels of fidelity; selection ofthe fidelity level is dependent upon the objectives of thesimulation and execution time constraints. However, rigorousfluid modelling may not necessarily improve performancesimulation accuracy unless all modelling assumptions andsources of uncertainty are aligned to the same level. Certainmodelling aspects such as the introduction of chemical kinetics,and dissociation effects, may reduce computational speed andthis is of significant importance for radical space explorationand novel propulsion cycle assessment.

    This paper describes and compares fluid models, based ondifferent levels of fidelity, which have been developed for anindustry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles.The latter comprises the following modules: engineperformance, aircraft performance, emissions prediction, andenvironmental impact. The work presented aims to fill thecurrent literature gap by: (i) investigating the commonassumptions made in thermo-fluid modelling for gas turbinesand their effect on caloric properties and (ii) assessing theimpact of uncertainties on performance calculations andemissions predictions at aircraft system level.

    In Part II of this two-part publication, the uncertaintyinduced in performance calculations by common technicalmodels, used for calculating caloric properties, is discussed atengine level. The errors induced by ignoring dissociation areexamined at 3 different levels: i) component level, ii) enginelevel, and iii) aircraft system level. Essentially, an attempt ismade to shed light on the trade-off between improving theaccuracy of a fluid model and the accuracy of a multidisciplinarysimulation at aircraft system level, againstcomputational time penalties. The results obtained demonstratethat accurate modelling of the working fluid is not alwaysessential; the accuracy/uncertainty for an overall engine modelwill always be better than the mean accuracy/uncertainty of the individual component estimates as long as systematic errors arecarefully examined and reduced to acceptable levels to ensureerror propagation does not cause significant discrepancies.Computational time penalties induced by improving theaccuracy of the fluid model as well as the validity of the idealgas assumption for future turbofan engines and novelpropulsion cycles are discussed.

  • 326.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University, UK.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Barbosa, Joao R.
    Instituto Technológico de Aeronáutica, São José dos Campos, Brazil.
    Lessons Learned From the Development of Courses on Gas Turbine Multidisciplinary Conceptual Design2013Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 135, nr 7, s. Article number 072601-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the need for highly qualified experts, multidisciplinary gas turbine conceptual design has not been a common study topic in traditional postgraduate curriculums. Although many courses on specialized topics in gas turbine technology take place, limited attention is given on connecting these individual topics to the overall engine design process. Teaching conceptual design as part of a postgraduate curriculum, or as an intensive short course, may help to address the industrial need for engineers with early qualifications on the topic, i.e., prior to starting their careers in the gas turbine industry. This paper presents details and lessons learned from: (i) the integration of different elements of conceptual design in an existing traditional Master of Science (MSc) course on gas turbine technology through the introduction of group design tasks and (ii) the development of an intensive course on gas turbine multidisciplinary conceptual design as a result of an international cooperation between academia and industry. Within the latter course, the students were grouped in competing teams and were asked to produce their own gas turbine conceptual design proposals within a given set of functional requirements. The main concept behind the development of the new design tasks, and the new intensive course, has been to effectively mimic the dynamics of small conceptual design teams, as often encountered in industry. The results presented are very encouraging in terms of enhancing student learning and developing engineering skills.

  • 327.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University, UK.
    Nalianda, Devaiah
    Cranfield University, UK.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A NOx Emissions Correlation for Modern RQL Combustors2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 2323-2330Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study begins with a review of existing emissions prediction methodologies for Rich-burn Quick-quench Lean-burn combustors. The need for a simple and adaptable NOx emissions correlation for such combustor designs as used in state-of-the-art civil turbofan engines is discussed. The derivation of a new correlation is consequently presented. The proposed model is computationally inexpensive and sufficiently accurate for use in aero-engine multi-disciplinary conceptual design tools. Furthermore, it is possible to adapt the correlation to model the NOx emissions of combustors designed for very aggressive future cycles. A case study is presented focusing on the NOx performance of advanced future cycles relative to current and future certification limits.

  • 328.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University, UK.
    Rolt, Andrew
    Rolls-Royce plc, UK.
    On the Optimisation of a Geared Fan Intercooled Core Engine Design2015Ingår i: Journal of Engineering for Gas Turbines and Power, ISSN 0742-4795, Vol. 137, nr 4, s. Paper N_GTP-14-1367-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. Thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to further analyse the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. The proposed design methodology is capable, with the utilised tool, of exploring the interaction of design criteria and providing critical design insight at engine-aircraft system level. Previous work by the authors focused on understanding the design space for this particular configuration with minimum specific fuel consumption, engine weight and mission fuel in mind. This was achieved by means of a parametric analysis, varying several engine design parameters - but only one at a time. The present work attempts to identify 'globally' fuel burn optimal values for a set of engine design parameters by varying them all simultaneously. This permits the non-linear interactions between the parameters to be accounted. Special attention has been given to the fuel burn impact of the reduced HPC efficiency levels associated with low last stage blade heights. Three fuel optimal designs are considered, based on different assumptions. The results indicate that it is preferable to trade overall pressure ratio and pressure ratio split exponent, rather than specific thrust, as means of increasing blade height and hence reducing the associated fuel consumption penalties. It is interesting to note that even when considering the effect of HPC last stage blade height on efficiency there is still an equivalently good design at a reduced overall pressure ratio. This provides evidence that the overall economic optimum could be for a lower overall pressure ratio cycle. Customer requirements such as take-off distance and time to height play a very important role in determining a fuel optimal engine design. Tougher customer requirements result in bigger and heavier engines that burn more fuel. Higher overall pressure ratio intercooled engine cycles clearly become more attractive in aircraft applications that require larger engine sizes.

  • 329.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University, UK.
    Rolt, Andrew
    Rolls-Royce plc, UK.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Multidisciplinary Analysis of a Geared Fan Intercooled Core Aero-Engine2014Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 136, nr 1, s. Article number 011203-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, along with the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. The thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is very little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to analyze the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. With minimum mission fuel in mind, the results indicate as optimal values a pressure ratio split exponent of 0.38 and an intercooler mass flow ratio of 1.18 at hot-day top of climb conditions. At ISA midcruise conditions a specific thrust of 86 m/s, a jet velocity ratio of 0.83, an intercooler effectiveness of 56%, and an overall pressure ratio value of 76 are likely to be a good choice. A 70,000 lbf intercooled turbofan engine is large enough to make efficient use of an all-axial compression system, particularly within a geared fan configuration, but intercooling is perhaps more likely to be applied to even larger engines. The proposed optimal jet velocity ratio is actually higher than the value one would expect by using standard analytical expressions, primarily because this design variable affects core efficiency at mid-cruise due to a combination of several different subtle changes to the core cycle and core component efficiencies at this condition. The analytical expressions do not consider changes in core efficiency and the beneficial effect of intercooling on transfer efficiency, nor do they account for losses in the bypass duct and jet pipe, while a relatively detailed engine performance model, such as the one utilized in this study, does. Mission fuel results from a surrogate model are in good agreement with the results obtained from a rubberized-wing aircraft model for some of the design parameters. This indicates that it is possible to replace an aircraft model with specific fuel consumption and weight penalty exchange rates. Nevertheless, drag count exchange rates have to be utilized to properly assess changes in mission fuel for those design parameters that affect nacelle diameter.

  • 330.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University, UK.
    Rolt, Andrew
    Rolls-Royce plc, UK.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Multi-disciplinary Analysis of a Geared Fan Intercooled Core Aero-Engine2013Ingår i: Proc. ASME. 55133; Volume 2: Aircraft Engine; Coal, Biomass and Alternative Fuels; Cycle Innovations, V002T07A027. GT2013-95474, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. Thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is very little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to analyse the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption.

    With minimum mission fuel in mind, the results indicate as optimal values a pressure ratio split exponent of 0.38 and an intercooler mass flow ratio just below 1.2 at hot-day top of climb conditions. At ISA mid-cruise conditions a specific thrust of 86m/s, a jet velocity ratio of 0.83, an intercooler effectiveness of 55% and an overall pressure ratio value of 76 are likely to be a good choice. A 70,000lbf intercooled turbofan engine is large enough to make efficient use of an all-axial compression system, particularly within a geared fan configuration, but intercooling is perhaps more likely to be applied to even larger engines.

    The proposed optimal jet velocity ratio is actually higher than the value one would expect by using standard analytical expressions primarily because this design variable affects core efficiency at mid-cruise due to a combination of several different subtle changes to the core cycle and core component efficiencies at this condition. Analytical expressions do not consider changes in core efficiency and the beneficial effect of intercooling on transfer efficiency, nor account for losses in the bypass duct and jet pipe, whilst a relatively detailed engine performance model such as the one utilised in this study does.

    Mission fuel results from a surrogate model are in good agreement with the results obtained from a rubberised-wing aircraft model for some of the design parameters. This indicates that it is possible to replace an aircraft model with specific fuel consumption and weight penalty exchange rates. Nevertheless, drag count exchange rates have to be utilised to properly assess changes in mission fuel for those design parameters that affect nacelle diameter.

  • 331.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University, UK.
    Rolt, Andrew M.
    Rolls-Royce plc.
    On the Optimisation of a Geared Fan Intercooled Core Engine Design2014Ingår i: Proc. ASME. 45653; Volume 3A: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration, V03AT07A018. GT2014-26064, 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. Thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to further analyse the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. The proposed design methodology is capable, with the utilised tool, of exploring the interaction of design criteria and providing critical design insight at engine-aircraft system level.

    Previous work by the authors focused on understanding the design space for this particular configuration with minimum specific fuel consumption, engine weight and mission fuel in mind. This was achieved by means of a parametric analysis, varying several engine design parameters — but only one at a time. The present work attempts to identify “globally” fuel burn optimal values for a set of engine design parameters by varying them all simultaneously. This permits the non-linear interactions between the parameters to be accounted. Special attention has been given to the fuel burn impact of the reduced HPC efficiency levels associated with low last stage blade heights.

    Three fuel optimal designs are considered, based on different assumptions. The results indicate that it is preferable to trade overall pressure ratio and pressure ratio split exponent, rather than specific thrust, as means of increasing blade height and hence reducing the associated fuel consumption penalties. It is interesting to note that even when considering the effect of HPC last stage blade height on efficiency there is still an equivalently good design at a reduced overall pressure ratio. This provides evidence that the overall economic optimum could be for a lower overall pressure ratio cycle. Customer requirements such as take-off distance and time to height play a very important role in determining a fuel optimal engine design. Tougher customer requirements result in bigger and heavier engines that burn more fuel. Higher overall pressure ratio intercooled engine cycles clearly become more attractive in aircraft applications that require larger engine sizes.

  • 332.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Cranfield University.
    Rolt, Andrew M.
    Rolls-Royce plc.
    Sethi, Vishal
    Cranfield University.
    On Intercooled Turbofan Engines2013Ingår i: Progress in Gas Turbine Performance / [ed] Ernesto Benini, Rijeka, Croatia: InTech, 2013, 1st, , s. 268s. 3-24Kapitel i bok, del av antologi (Refereegranskat)
  • 333.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, JanMälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Developments in Combustion Technology2016Samlingsverk (redaktörskap) (Refereegranskat)
    Abstract [en]

    Over the past few decades, exciting developments have taken place in the field of combustion technology. The present edited volume intends to cover recent developments and provide a broad perspective of the key challenges that characterize the field. The target audience for this book includes engineers involved in combustion system design, operational planning and maintenance. Manufacturers and combustion technology researchers will also benefit from the timely and accurate information provided in this work. The volume is organized into five main sections comprising 15 chapters overall: - Coal and Biofuel Combustion - Waste Combustion - Combustion and Biofuels in Reciprocating Engines - Chemical Looping and Catalysis - Fundamental and Emerging Topics in Combustion Technology

  • 334.
    Kyprianidis, Konstantinos
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, JanMälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Developments in Near-Infrared Spectroscopy2017Samlingsverk (redaktörskap) (Refereegranskat)
    Abstract [en]

    Over the past few decades, exciting developments have taken place in the field of near-infrared spectroscopy (NIRS). This has been enabled by the advent of robust Fourier transform interferometers and diode array solutions, coupled with complex chemometric methods that can easily be executed using modern microprocessors. The present edited volume intends to cover recent developments in NIRS and provide a broad perspective of some of the challenges that characterize the field. The volume comprises six chapters overall and covers several sectors. The target audience for this book includes engineers, practitioners, and researchers involved in NIRS system design and utilization in different applications. We believe that they will greatly benefit from the timely and accurate information provided in this work.

  • 335.
    Lam, H. L.
    et al.
    Hon Loong Lam Centre of Excellence for Green Technologies, University of Nottingham Malaysia Campus, Malaysia.
    Varbanov, P. S.
    University of Pannonia, Veszprém, Hungary.
    Klemeš, J. J.
    University of Pannonia, Veszprém, Hungary.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology (KTH), Stockholm, Sweden.
    Green Applied Energy for sustainable development2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 161, s. 601-604Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    This special issue of Applied Energy contains articles developed from initial ideas related to the 17th Conference Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES 2014) held in Prague, Czech Republic, during 23-27 August 2014. The conference has been organised jointly with CHISA 2014. Both events have benefitted from the shared pool of participants as well as the expanded opportunities for exchanging ideas. From all contributions presented at the conference, high-quality ones suitable for Applied Energy, have been invited. Overall, 37 extended manuscripts have been invited as candidate articles. Of those, after a thorough review procedure, 11 articles have been selected to be published. The topics attained in the focus of this Special Issue include Process Integration and Energy Management, CO2 capture, and Green Energy Applications. 

  • 336.
    Larsson, David
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Stridh, Bengt
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Solar Electricity in Swedish District Heating Areas: Effective Energy Measures in Apartment Buildings to Increase the Share of Renewable Energy in Europe2014Ingår i: Proceedings from the 14th International Symposium on District Heating and Cooling / [ed] Anna Land, Stockholm: Svensk Fjärrvärme , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    To overcome the climate challenge is one of the greatest tasks of our time. In EU, renovating the existing building stock has been found an effective measure. In Swedish buildings with district heating, lowering heat demand could be questioned, because the energy used is mainly renewable bio energy or waste heat from industries. In addition many district heating systems cogenerate electricity, which could reduce the overall European greenhouse gas emissions.

    The aim of this article is to find effective measures for Swedish apartment buildings, in order to increase the share of renewable energy in European energy consumption. As a basis we use a previous study of energy saving potentials in apartment buildings. Added to this we study the impact of heat savings in 30 of Sweden’s largest district heating systems.

    The results show that on average heat reductions will lead to a decreased share of renewable energy, while electricity reductions will lead to an increased share of renewables. Of the investigated measures, using photovoltaics for local solar electricity generation has the largest potential.

    Our conclusion is that using the potential of solar electricity production should be considered in national energy policy and future building requirements. Heat reduction, on the other hand, could have lower priority in district heating areas, at least for existing buildings.

  • 337.
    Larsson, Eva K.
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Separation of methane2013Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Gasification with gas cleaning and direct separation of methane, where the residual gas can be used in a conventional boiler, is an attractive scenario in regard to flexible production of methane, power and heat. The technological challenge is to separate methane from a product gas with a low methane content and also complex composition.

    Membranes have several attractive properties for this application. They consume no energy input for their operation, as long as the feed is pressurized and no recirculation etc. is needed. They have attracted a great deal of interest in the last decades for separation of methane and carbon dioxide from anaerobic digestion biogas production and for treatment of natural gas. They have the potential to offer cost effect­tive solutions also for smaller plants, since they are delivered in modules that can be duplicated to fit the size of the plant. For these reasons, it was chosen to concentrate the study on membranes. Alternative separation methods that were considered are cryogenic separation and pressure swing adsorption (PSA).

    Membranes separate gases based on differences in gas components’ diffusivity and solubility in the (polymer) membrane material. It was found that both these factors differ too little between CH4 and N2 to assume a possibility to separated them, if N2 is a large part of the gas composition, as is the case in air-blown gasification. Therefore, it was concluded that membrane separation is not an option for air-blown gasification. Instead, a gas from oxygen-blown CFB gasification or from dual bed indirect gasification was set as the input gas, thereby eliminating the problem with N2 in the search for suitable membranes. The main components in the gas are then H2, CO, H2O, CO2, CH4 and some higher hydrocarbon. An ideal separation would yield only CH4 and higher hydrocarbons in one stream and the other components in another.

    There are two kinds of membranes, glassy, that separate mainly based on size, and rubbary, that separate mainly based on solubility which is closely connected to the boiling point of the gas components. Calculations were made on a typical glassy membrane. It was found that the problem is that the separation between CH4 and CO is insufficient. Therefore, a two-step membrane separation with a shift step between was tried. The shift reaction, CO + H2O -> H2 + CO2, introduces a gas composition to the second membrane that is more easily separated. Even with the possibly overoptimistic conditions set in this preliminary calculation, the result is unsatisfactory. The achieved CH4 percentage is only 80% and 30% of the methane is lost in the gas streams that will be combusted for heat and power production. Also, this separation option would require a rather complicated process. The conclusion is that it is unlikely that this concept would be attractive, even after modifications to achieve better percentage values. 

    Rubbary membranes have also been considered. Based on the separation factors, it can be conclu­ded that they would require upstream separation of H2O and CO2 by a glassy membrane or other gas processing methods, before a rubbary membrane could perform the separation between CH4 and H2+CO. It is, however, unlikely that this separation would be sufficiently good, at least in a one-step system.

    A possible way to increase performance of membranes is to use liquid membranes that has a liquid to absorb gas components that have permeated through the membrane. No publications have been found on specific liquid membranes that could be suitable for the separation in question. Liquid membranes intrinsically add the need for regeneration of the liquid phase. Further search for liquid membranes is assessed as one of the interesting routes for continued investigations on separation. 

    Cryogenic separation can be expected to fulfil the requirements on gas quality and minimizing CH4 loss. The drawback is that a cryogenic plant would mean substantial investment cost and energy consumption. A conclusion from a rough cost analysis is that the cryogenic alternative seems to have the potential to be cost effective and should be included in further studies.

    Liquid membranes, cryogenic and also PSA etc. are all worth considering for the separation process.

  • 338.
    Larsson, Ida
    et al.
    SP Sveriges Tekniska Forskningsinstitut, Sweden.
    Lönnermark, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. SP Fire Research.
    Blomqvist, Per
    SP Fire Research, Sweden.
    Persson, Henry
    SP Fire Research, Sweden.
    Rahm, Michael
    SP Fire Research, Sweden.
    Small scale screening tests to assess the self-heating potential of wood pellets2013Ingår i: Interflam 2013: Proceedings of the thirteenth international conferemce, London, UK: Interscience Communications , 2013, s. 623-628Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The use of biomass pellets is increasing. As a consequence, large indoor storage facilities are needed along the transportation chain. A number of fire incidents due to spontaneous ignition in wood pellets have been reported. The aim of the present work is to provide methods for estimating risks for self-heating from pellets stored in bulk quantities. The experimental work ranges from small-scale characterizations to medium-scale storage tests and includes different types of pellets. One aim has been to develop small scale screening methods to assess the propensity for self-heating, thereby trying to define the specific type of “activity” occurring in the pellets as well as characterising it.

     

    Isothermal calorimetry (micro calorimeter) has been used as small scale screening test method and the results has then been validated with crossing point tests and in medium scale tests (1 m3). Thirteen samples from different types of pellets have been ranked relative to each other in micro calorimeter tests and two pellet types; one “reactive” and one “less reactive” were also tested for validation in crossing point and medium scale. The results clearly reveal that different activity levels of the pellets can be measured using small scale screening methods.

  • 339.
    Larsson, Ida
    et al.
    SP Fire Research.
    Lönnermark, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. SP Fire Research.
    Persson, Henry
    SP Fire Research.
    Blomqvist, Per
    SP Fire Research.
    Temperature Measurements and Examination of Self-heating in Large Scale storage of Wood Pellets2014Ingår i: World Bioenergy 2014, Jönköping, Sweden, 2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This paper summarizes the experimental data from a large-scale storage test performed within the European project called SafePellets. Temperature measurements were made inside a silo with a capacity of storing 3000 ton of wood pellets, from August to October in 2013. The purpose of the test was to examine the self-heating of the wood pellets, where and when it occurs, how it spreads and if it could be connected to certain events. For temperature measurements, both the temperature cables belonging to the silo temperature surveillance system and thermocouples mounted by SP at the cables and on the in/out-side walls of the silo were used.

     

    The results clearly reveal that self-heating occurs almost instantly after start of filling the silo and temperatures above 40 °C inside the pellets bulk is regular. The temperature surveillance system, which was set to give an alarm signal for high temperatures, was activated several times during the test period and temperatures exceeding 60 °C were registered at several occasions. Measurements above the pellet surface also show that this headspace temperature varies much with the outside ambient temperature and the sunlight radiation. A sunny summer’s day, the headspace temperature could easily reach above 40 °C, which will influence the pellet bulk. The project also emphasized an important problem when it comes to silo storage. The problem of temperature sensor cables inside the silo not always hanging where they are supposed to be was observed in the test and dealt with.

  • 340.
    Leduc, S.
    et al.
    International Institute for Applied System Analysis, Laxenburg, Austria.
    Wetterlund, E.
    Linköping University.
    Dotzauer, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kindermann, G.
    International Institute for Applied System Analysis, Laxenburg, Austria.
    CHP or biofuel production in Europe?2012Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 20, s. 40-49Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the opportunity to invest in combined heat and power (CHP) plants and second-generation biofuel production plants in Europe is investigated. To determine the number and type of production plants, a mixed integer linear model is used, based on minimization of the total cost of the whole supply chain. Different policy scenarios are studied with varying values of carbon cost and biofuel support. The study focuses on the type of technology to invest in and the CO2 emission substitution potential, at constant energy prices. The CHP plants and the biofuel production plants are competing for the same feedstock (forest biomass), which is available in limited quantities. The results show that CHP plants are preferred over biofuel production plants at high carbon costs (over 50 EUR/tCO2) and low biofuel support (below 10 EUR/GJ), whereas more biofuel production plants would be set up at high biofuel support (over 15 EUR/GJ), irrespective of the carbon cost. Regarding the CO2 emission substitution potential, the highest potential can be reached at a high carbon cost and low biofuel support. It is concluded that there is a potential conflict of interest between policies promoting increased use of biofuels, and policies aiming at decreased CO 2 emissions.

  • 341.
    Lee, Duu-Jong
    et al.
    Natl Taiwan Univ Sci & Technol, Taiwan.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Inst Technol, Stockholm, Sweden.
    Chou, Siaw-Kiang
    Natl Univ Singapore, Singapore.
    Desideri, Umberto
    Univ Perugia, Perugia, Italy.
    Clean, efficient, affordable and reliable energy for a sustainable future Preface2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, s. 1-3Artikel i tidskrift (Övrigt vetenskapligt)
  • 342.
    Lee, M.
    et al.
    National Taiwan University, Taipei, Taiwan.
    Keller, A. A.
    University of California, Santa Barbara, CA, United States.
    Chiang, P. -C
    National Taiwan University, Taipei, Taiwan.
    Den, W.
    Tunghai University, Taichung, Taiwan.
    Wang, H.
    Tongji University, Shanghai, China.
    Hou, C. -H
    National Taiwan University, Taipei, Taiwan.
    Wu, J.
    Tongji University, Shanghai, China.
    Wang, X.
    Tongji University, Shanghai, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Tongji University, Shanghai, China; Royal Institute of Technology (KTH), Sweden.
    Water-energy nexus for urban water systems: A comparative review on energy intensity and environmental impacts in relation to global water risks2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 205, s. 589-601Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The importance of the interdependence between water and energy, also known as the water-energy nexus, is well recognized. The water-energy nexus is typically characterized in resource use efficiency terms such as energy intensity. This study aims to explore the quantitative results of the nexus in terms of energy intensity and environmental impacts (mainly greenhouse gas emissions) on existing water systems within urban water cycles. We also characterized the influence of water risks on the water-energy nexus, including baseline water stress (a water quantity indicator) and return flow ratio (a water quality indicator). For the 20 regions and 4 countries surveyed (including regions with low to extremely high water risks that are geographically located in Africa, Australia, Asia, Europe, and North America), their energy intensities were positively related to the water risks. Regions with higher water risks were observed to have relatively higher energy and GHG intensities associated with their water supply systems. This mainly reflected the major influence of source water accessibility on the nexus, particularly for regions requiring energy-intensive imported or groundwater supplies, or desalination. Regions that use tertiary treatment (for water reclamation or environmental protection) for their wastewater treatment systems also had relatively higher energy and GHG emission intensities, but the intensities seemed to be independent from the water risks. On-site energy recovery (e.g., biogas or waste heat) in the wastewater treatment systems offered a great opportunity for reducing overall energy demand and its associated environmental impacts. Future policy making for the water and energy sectors should carefully consider the water-energy nexus at the regional or local level to achieve maximum environmental and economic benefits. The results from this study can provide a better understanding of the water-energy nexus and informative recommendations for future policy directions for the effective management of water and energy.

  • 343.
    Lehmayr, B.
    et al.
    Stuttgart University, Germany.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Alexiou, Alexios
    National Technical University of Athens, Greece.
    Xu, Lei
    Siemens.
    TERA2020 - Optimisation of NEWAC Configurations2010Konferensbidrag (Refereegranskat)
  • 344.
    Lei, Zeng
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. CLASP, Beijing, Peoples R China.
    Yang, Yu
    CLASP, Beijing, China.
    Jiayang, Li
    CLASP, Beijing, China.
    China's Promoting Energy-Efficient Products for the Benefit of the People Program in 2012: Results and analysis of the consumer impact study2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 133, s. 22-32Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    China launched the largest ($4.26 billion) energy-efficient appliances subsidy program in June 2012. This paper investigates the impact of this program on consumers by surveying 2630 consumers in 10 cities with different socioeconomic statuses. The results showed that the Chinese consumers were very conscious about electricity savings and that they considered energy-saving an important factor when selecting appliances. Only 13% of consumers claimed that the subsidy was the primary reason for them to purchase energy-efficient appliances. The study found that the subsidy program raising a moderate level of awareness, with 62% of interviewed consumers being aware of the program. However, the consumers were found to lack an in-depth understanding of the program. More budget allocation for marketing and outreach could potentially improve the public awareness of energy-efficient appliances and facilitate market transformation in the long run. Compared with conventional appliances, most Chinese consumers were only willing to pay less than 10% more for energy-efficient appliances. The consumers' expectation for the subsidy size varied between cities, but on average, they would become very likely to purchase energy-efficient appliances when the subsidy size was between 20% and 30%. It was suggested that in the future, only Tier 1 appliances (the most efficient) would be subsidized, and the size of the subsidy should be increased so to meet the consumers' expectations. 

  • 345.
    Lennermo, Gunnar
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energianalys AB, Sverige.
    Lauenberg, Patrick
    Lund University, Sweden.
    Distributed heat generation in a district heating system2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    District heating (OH) systems need to be improved  regarding integration  of decentralised  heat generation. Micro production, prosumers and smart grids are terms becoming more and more common  in  connection  to  the  power  grid.  Concerning district  heating,  the  development  is slower, although improving. Today there are a number of such decentralised units for heat generation,  mainly  solar,  that have been partly evaluated.  Previous  studies  have shown  that there is a need to develop a better control system for the connection to the district heating grid.

    In principle  there are four different ways to connect  a local heat generator  to a OH grid. The most  common  technology  is Return/Supply   connection  (R/S). In this concept it is necessary to use a feed-in pump and equipment  to get correct temperatures  and flows.

    Evaluatian of solar thermal (ST) installations in Sweden shows that the feed in flow and heat-power  vary considerably;  more than the heat-power  productian  from  the ST plant.  This causes a drop in heat generation from the solarthermal system. However, if the ST installation is small in relation to the OH system, it will not cause any problems  for the OH system. There are more than 20 R/S ST installations in Sweden and up until recently, no complaints from OH Campanies regarding poor performance were recorded.

  • 346.
    Lennermo, Gunnar
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lauenburg, P.
    Lunds universitet, Sverige.
    Brand, L.
    Lunds universitet, Sverige.
    Decentralised heat supply in district heating systems: Implications of varying differential pressure2014Ingår i: Proceedings from the 14th International Symposium on District Heating and Cooling September, 6-10, 2014 Stockholm, SWEDEN ISBN 978-91-85775-24-8 / [ed] Anna Land, Swedish District Heating Association, 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    There is a rising interest for the integration of decentralised heat supply in district heating (DH) systems in the form of so-called prosumers, i.e., customers that both can withdraw and supply heat to the grid. The interest comes from a growing interest in local energy supply among owners of property as well as a growing awareness among DH companies about the need to view their customers more like partners rather than just consumers of heat.In a previous study, decentralised solar heat plants in Sweden were mapped out and their performance were evaluated. In general, the performance in terms of delivered heat was at least 20% lower than expected. The main reason for this is deficiencies regarding the feed-in of theheat to the grid, caused by an inability of the control system to handle the variation of the differential pressure between the supply and the return pipe in the DH network. These variations, caused mainly by the rapid load fluctuations caused by consumption of domestic hot water, has so far been overlooked when designing the control system.

    This paper describes and pins down this problem with support from measurements and simulations of differential pressure.There are different ways to connect decentralised heat supply, where a primary return/supply connection is the most common, implying the heat being added to the DH water before the customer's substation or directly to the DH supply pipe. Although the field study-objects utilise solar energy, it must be emphasised that the results from the project will be of general interest for any type of decentralised heat supply, e.g. surplus heat from local cooling machines or industrial processes. Suggestions for improved control strategies is given in the paper and future work will aim to support them.Keywords: Prosumers, decentralised heat supply, differential pressure, return/supply connec

  • 347.
    Lennermo, Gunnar
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energianalys AB, Alingsås, Sweden.
    Lauenburg, P.
    Lund university, Sweden.
    Werner, S.
    Halmstad university, Sweden.
    Control of decentralised solar district heating2019Ingår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 179, s. 307-315Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of decentralised solar district heating plants is to feed solar heat directly into district heating networks. This decentralised heat supply has to consider two major output conditions: a stable required feed-in supply temperature and a feed-in heat power equal to the heat output from the solar collectors. However, many installations cannot achieve the second output condition, since severe oscillations appear in the feed-in heat power. This problem can be solved by two different control concepts with either temperature- or flow-control. Detailed measurements from two reference plants are provided for these two different control concepts. One main conclusion is that a robust control system is characterized by the ability to provide required flows and temperatures. The major difference between robust and less robust control is that the supply temperatures and/or flows do not fluctuate even if the input conditions are unfavourable. 

  • 348.
    Lennermo, Gunnar
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lauenburg, Patrick
    Lund University, Faculty of Engineering, Energy Sciences, Sweden.
    Feed-in from Distributed Solar Thermal Plants in District Heating Systems2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    A District heating (DH)feed-in system is connected to the DH system outside themain central pumps. There are fourdifferent ways to connect a feed-in system to the DH main line but the most frequently used are return/return (R/R) and return/supply (R/S). R/S is the most beneficial system sinceit influencesthe DH system the least. For an R/S feed-in system, there are two basic control concepts; a temperature controlled system and a flow controlled system. In the temperature controlled system there is always a shunt flow which the flow controlled system lacks. It is possible to build a combination feed-in system but the risk of poor performance increases. More field testswill be done during the summer 2017.

  • 349.
    Lennermo, Gunnar
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Energianalys AB, Sverige.
    Lauenburg, Patrick
    Lunds universitet, Sverige.
    Brange, Lisa
    Lunds universitet, Sverige.
    Små värmekällor: Kunden som prosument2016Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Det finns stor potential att ta tillvara lokal, småskalig värme i fjärrvärmesystemen. Små värmekällor kan utgöras av industriell restvärme, solvärmeanläggningar, krematorier och olika sorters kylmaskiner i lokaler, idrottsanläggningar och butiker. Prosument är ett begrepp som blir allt vanligare för att beskriva en fjärrvärmekund som både köper och säljer fjärrvärme. Fjärrvärmeföretagens egna topplast- eller reservpannor är också intressanta ur denna rapports perspektiv som behandlar hur inmatningen av värme från en prosument till fjärrvärmenätet görs på bästa sätt.

    Många mindre värmekällor har uppvisat problem med pendlingar i inmatad effekt och flöde. Detta kan ha direkt negativ inverkan på värmekällans prestanda – exempelvis genom att solfångare får lägre värmeutbyte. I ett framtida scenario där små värmekällor står för ett betydande bidrag till fjärrvärmen, måste lokal värmeinmatning fungera tillfredsställande. Denna studie har syftat till att undersöka varför det uppstår pendlingar i inmatningssystemen och vad som kan göras för att dessa ska undvikas.

    De två vanligaste varianterna för lokal inmatning är retur/retur (R/R) och retur/fram (R/F) vilket innebär att fjärrvärmevatten tas från returledningen, värms av den lokala värmekällan och matas tillbaka in i fjärrvärmesystemets retur- respektive framledning. R/R är mindre komplicerad men behäftad med fler nackdelar, framför allt att den höjer returtemperaturen i fjärrvärmesystemet. R/F är det inkopplingssätt som förefaller vara mest användbart men som samtidigt är mer komplext att reglera. Det är i R/F-system som pendlingar i inmatningen påträffats och skälet är att regleringen inte lyckats ta hänsyn till att det största tryckmotstånd som ska övervinnas i inmatningen är fjärrvärmenätets differenstryck. Differenstrycket beror inte av inmatningsflödets storlek vilket får till följd att när denna tryckskillnad är övervunnen av inmatningssystemet blir flödet väldigt lätt för stort. Ju större differenstryck och ju mindre anläggning desto större är risken för detta förlopp.

    Grundprincipen, som kan tyckas självklar, är att den inmatade effekten ska vara lika stor som den tillgängliga. Om inte ett värmelager används, vilket är mindre önskvärt av praktiska och ekonomiska skäl, kan detta åstadkommas på två olika sätt: antingen med ett flödesreglerat eller med ett temperaturreglerat system.I ett flödesreglerat system ska det inte finnas någon kortslutningsledning (shunt) mellan retur- och framledningen. Det inmatade flödet ska styras med inmatningspumpen med eller utan hjälp av en 2-vägsventil som ligger i serie med pumpen.

    I ett temperaturreglerat system ska det finnas en kortslutningsledning som aldrig får stängas. Stängs den blir det ett flödesreglerat system och det ställer helt andra krav på styrningen av inmatningspumpen. Inmatningspumpens varvtal styrs efter en börvärdeskurva där ärvärdet utgörs av differenstrycket. Eftersom differenstrycket är relativt stort och konstant (ur ett kortsiktigt perspektiv) så är det enklare att balansera det inmatade flödet med en tvåvägsventil än en trevägsventil i kortslutningsledningen.Värmekällor som kräver en given returtemperatur eller som inte kan lyfta hela temperatursteget kan med fördel kan anslutas temperaturreglerat medan värmekällor som ska arbeta vid så låg temperatur som möjligt eller kylas så långt det går bör anslutas flödesreglerat, eventuellt med en temperaturreglerad uppstart.

  • 350.
    Lennermo, Gunnar
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Persson, Tomas
    Högskolan Dalarna, Energi och miljöteknik.
    Perers, Bengt
    Högskolan Dalarna, Energi och miljöteknik.
    Pettersson, Ulrik
    Johansson, Mathias
    Underlag för utökad besiktning av bio- och solvärmesystem: Formulär med analyshjälp2011Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Det är svårt att på ett genomarbetat sätt, kontrollera en solvärmeanläggning som är i drift och det blir svårare när solvärmesystemet skall samverka med en biobränsleanläggning, som har sina speciella egenheter. Det enklaste och, som det kan tyckas, bästa sättet att kontrollera om en solvärmeanläggning fungerar, är att beräkna utifrån en värmemängdsmätare, som förhoppningsvis finns i anläggningen, hur mycket energi per m2 aktiv area som solfångaren har producerat per år. Om produktionen ligger mellan 300 – 350 kWh/m2 så är det bra. Det är dock så att en solvärmeanläggning borde kunna producera betydligt mer värme om den bara ges lite bättre förutsättning eller att den faktiskt kan ge mindre, men ändå uppfylla de krav som ställdes. Det behöver inte nödvändigtvis vara antalet producerade solfångar-kWh värme som är högt utan det viktigaste kanske är att antalet inbesparade kWh biobränsle är många. För att kunna få ett grepp om hur en solvärmeanläggning fungerar i sitt sammanhang så bör det totala systemet redovisas framför allt med avseende på: -Värmedistributionssystemets uppbyggnad. Var och när finns kallt vatten som ska värmas samt hur mycket. -Energi- och effektnivåer för olika delar av systemet och fram för allt under sommaren -Vilka pannor och bränslen som används, framför allt med betoning på reglerbarhet Solvärmekretsen, som inte är speciellt annorlunda utformad än i andra lite större solvärmeanläggningar ges i den här rapporten relativt stort utrymme, eftersom den samlade kompetensen bland de som gör besiktningar och kontroller inte är så hög. De delar som berörs mest är: -Trycket i solvärmeanläggningen med avseende på expansionskärlets förtryck, systemets uppfyllnadstryck och driftsfunktioner -Flödet i anläggningen som inriktar sig på luftmedryckning, flödesfördelning och vanliga flödeshastigheter -Solfångarnas energi- och värmeeffektproduktion Huvuddelen av underlagsmaterialet bör ha samlats in före besöket, genom att försöka få tag på: -Förstudier för solvärme- och pannanläggning -Förfrågningsunderlag för i första hand solvärmeanläggningen -Driftstatistik -Data på hur det totala systemet ser ut. Dessa data bör bearbetas innan besöket på plats vilket skall inkludera en genomgång av driftsansvarig vilket kompletteras med en guidad tur genom anläggningen. Besöket bör också vara förberett hos driftsansvariga så att stegar för att komma åt solfångarna finns framtagna och de säkerhetsselar som skall finnas vid okulär inspektion finns tillgängliga. Efter avslutad på platsen kontroll ska en besiktningsrapport skrivas. Mycket underlagsberäkningar ska skickas med som bilaga samt en lista med punkter som syftar till att få en effektivare sol- och biobränsleanläggning.

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