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  • 1.
    Al Hamrani, Emad
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Grönberg, Nils
    Mälardalen University, School of Business, Society and Engineering.
    Sustainable flue-gas quench: For waste incineration plants within a water-energy-environment nexus perspective2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The function of a flue-gas quench is to remove additional contaminants from flue-gas and to reduce the wastewater from a waste incineration plant. The aim of this degree project is to find how the system is affected by using a quench and what factors limits the performance. This is done by modelling and simulating a waste incineration plant in Aspen Plus. Data and plant schematics were obtained by a study visit to Mälarenergi Plant 6 situated in Västerås, Sweden, which were used as model input and for model validation. The results have shown that the amount of wastewater can be reduced by more than half compared to a plant without a quench. The heat produced in the condenser, when discharging water to the boiler, would be lowered by up to 20%. For systems with a quench present when more water was discharged to the boiler both the heat production and the pollutant capturing became better. However, the system has limits regarding the amount that could be recirculated, in the form of temperature limits in different parts of the system. In addition, if the heat load is low there is an insufficient amount of wastewater generated in the condenser to run the quench. In that situation, clean (fresh) water needs to be used instead. Using clean water is unwanted since the plant will then consume more resources while still producing less heat than a plant without a quench would.

  • 2.
    Andersson, Ellen
    Mälardalen University, School of Business, Society and Engineering.
    Nära-nollenergibyggnader: En fallstudie av ett flerbostadshus förutsättningar att klara Boverkets framtida krav2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order to develop energy-efficient constructions all new buildings will be nearly-zero energy buildings by year 2021. A nearly-zero energy facility is a building with high energy performance and very low energy consumption, where the amount of energy that needs to be supplied to the building will largely originate from renewable sources that are often self-produced on site or nearby. On December 15, 2016 BFS 2016: 13 - BBR 24 was introduced with requirements for verification of the building's specific energy use. The new regulations for nearly-zero energy buildings will be introduced in two stages through BBR (A) and BBR (B). BBR (A) implies no aggravation of requirements, but introduces a new way of calculating the energy performance of the building measured in primary energy. Primary energy factors are introduced per energy carrier, where the energy carrier for electric heating receives a higher value then other energy carriers. A projected five-storey apartment building located in Sigtuna, Stockholm has been investigated and energy calculations and simulations have been carried out in the energy calculation program IDA Indoor Climate and Energy. Simulations have been carried out on a reference object, focusing on analyzing how the energy utilization of the building is affected by various actions. The measures investigated are energy supply and origin of this, changes in the building construction and technical systems. The result shows that with relatively small changes the required demands of close-zero energy buildings can be reached. Changes to the building construction through better exterior wall insulation, better U-values ​​of building constructions and increased efficiency of heat exchanger, make demands for near-zero energy buildings in BBR (B). With self-produced electricity via solar cells the primary energy for the building will be even lower. The hardest challenge comes for the electricity heated buildings which due to an increased primary energy factor, will get harder to meet the future requirements due to a higher demand level.

  • 3. Andrén, Lars
    et al.
    Persson, Tomas
    Högskolan Dalarna, Energi och miljöteknik.
    Lennermo, Gunnar
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Handbok för kombinerade sol- och biovärmesystem: Teknik - System - Ekonomi2012Report (Other academic)
    Abstract [sv]

    Handboken beskriver olika solfångarkonstruktioner och solvärmekretsens ingående komponenter och ger en grundlig inblick i ackumulatortankens konstruktion och funktion. I boken finns förslag på systemutformning, olika tekniska lösningar och hur systemen bör styras och regleras. Handboken beskriver i första hand utformning-lösning-styrning av kombinationen sol- och pelletsvärme, men tar även upp solvärme i kombination med vedpannor, värmedrivna vitvaror och värmepumpar. Värmesystem med vattenburen värme är utmärkta att kombinera med solvärme, men det är i de flesta fall enklare att få till bra lösningar vid nyinstallation, än vid komplettering av befintlig anläggning. När solvärme och pelletsvärme ska kombineras finns det många alternativ till systemutformning. Det är viktigt att vattenburna pelletssystem utformas korrekt och kombineras på rätt sätt med solvärme för att komforten ska bli hög och elanvändningen låg. Vattenmantlade pelletskaminer med ett vattenburet värmesystem är extra intressant i kombination med solvärme. När eldningen upphör i samband med att värmebehovet avtar kan solvärmen ta över. En generell slutsats är att konventionella svenska pelletspannor med inbyggd varmvattenberedning inte är lämpliga i kombination med solvärmesystem. Den typen av bränslepannor ger komplicerade systemlösningar, höga värmeförluster och det är svårt att åstadkomma en tillräckligt bra temperaturskiktning i ackumulatortanken om varmvattenberedning sker i pannan. Solvärme för varmvattenberedning kan vara ett enkelt och bra komplement till pelletskaminer som genererar varmluft. För solvärmesystem är det viktigt att kraftig temperaturskiktning erhålls när värmelagret laddas ur. Det betyder att ackumulatortankens (eller varmvattenberedarens) nedre vattenvolym ska kylas ner till temperaturer som ligger nära ingående kallvattentemperatur. Ackumulatortankens mellersta del bör kylas till samma temperatur som radiatorreturen. Vid design av solfångarkretsen måste överhettning och stagnation kunna klaras utan risk för glykolnedbrytning eller andra skador på värmebärare eller rörkrets (och andra komponenter i kretsen). Partiell förångning minskar risken för att glykolen skadas då solfångaren når höga stagnationstemperaturer. Solfångarens glykolblandning tillåts koka (förångas) på ett kontrollerat sätt så att endast ånga blir kvar i solfångaren. Vätskevolymen i solfångaren samlas upp i ett större expansionskärl och systemet återfylls när vätskan kondenserar. Dränerande solfångarsystem med enbart vatten är ett möjligt alternativ till konventionella solfångare. De kräver en större noggrannhet vid installationen, så att sönderfrysning undviks. Dränerande systemlösningar är relativt ovanliga i Sverige. Om solfångaren under senhöst-vinter-tidig vår kan arbeta med att förvärma kallvatten från 10 till 20 ºC erhålls en betydligt bättre verkningsgrad på solfångaren (och framför allt ökar värmeutbytet då drifttimmarna ökar väsentligt) än om radiatorreturen (som i bästa fall ligger på temperaturnivån 30 - 40 ºC) ska förvärmas. Därför bör radiatorreturen placeras en bra bit upp från botten i ackumulatortanken och tappvarmvattnet ska förvärmas i en slinga som börjar i tankens botten. Om det finns ett VVC-system måste systemet anslutas på ett speciellt sätt så att ackumulatortankens temperaturskiktning inte störs. En viktig parameter vid ackumulatortankens utformning är att värmeförlusterna hålls låga. Det är viktigt för att klara tappvarmvattenlasten med solvärme under mulna perioder sommartid (men också för att hålla energianvändningen låg). I moderna hus, där ackumulatortanken i regel placeras i bostaden, blir det en komfortfråga att undvika övertemperaturer i det rum där värmelagret placeras. En bra standard på isoleringen (med minimerade värmeförluster) kräver att det finns ett lufttätt skikt över hela isoleringen som dessutom sluter tätt mot röranslutningar. Ofrivillig självcirkulation i anslutande kretsar som kan kyla av och blanda om ackumulatortankens vattenvolym, bör förhindras med backventiler och nedböjning av rören i isolerskiktet eller direkt utanför tanken.

  • 4.
    Bartusch, Cajsa
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Boosting behavioral change in residential electricity consumption: demand response programs and feedback2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    As part of realizing national and European climate ambitions, it is imperative to bring about increased energy efficiency and consumption flexibility in the residential sector of the Swedish power market. In addition to governmental policy instruments to this end, market-based measures play an important role in making behavioral change in domestic electricity use happen. In light of the prevailing lack of incentives for residential consumers to save electricity and cut peak demand at times of physical and financial market constraints, the research studies that form the basis of this thesis have the aim of adding to the body of knowledge on policy instruments for the purpose of boosting behavioral change in residential electricity consumption. The research has accordingly contributed to the general statistics on residential electricity consumption, which constitute the starting point for policy instrument development, and augmented knowledge on the merits of residential demand response programs involving hourly settlements in power trading and demand-based, time-of-use tariffs in power distribution as well as graphic feedback on individual households’ electricity use by means of a statistics service provided over the Internet.

     

    The overall results have shown that household behavior, together with physical factors such as heating systems, help explain the sizeable differences in electricity consumption among homeowners. Statistical analysis of variance has in this context proven to be an effective method for identifying key indicators of policy development. Power suppliers and electricity consumers as well as society as a whole have been found to gain substantially from hourly settlements in retail. To suppliers, the greatest benefits are associated with risk management, while the major advantage to customers is that they are provided with an opportunity to reduce their electricity costs. It has also been empirically demonstrated that electricity users are willing to adjust their consumption to a demand-based, time-varying distribution tariff. Households generally have a favorable attitude towards this type of distribution tariff, seeing as they indirectly have a positive impact on the environment. Providing households with feedback over the Internet on their individual electricity use and demand has been shown to contribute to an increased awareness and lead to energy efficiency in homes. Easy accessibility and simplicity have proven to be key success factors in this context. Combining conventional bar charts, color symbolism and historic feedback is expedient in this respect.

  • 5.
    Bartusch, Cajsa
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Visualisering av elanvändning i flerbostadshus: Delrapport inom ELAN Etapp III2011Report (Other academic)
    Abstract [sv]

    Elanvändningen i våra bostäder sker utan närmare eftertanke och reflektion. Återkopplingen avseende hushållens individuella elanvändning är i det avseendet mycket betydelsefull. I dagsläget är dock den förbrukningsinformation som hushållen har tillgång till mycket begränsad, i synnerhet i flerbostadshus. Syftet med projektet Visualisering av elanvändning i flerbostadshus är att utveckla och utvärdera designkoncept för individuell återkoppling till hushåll som bor i lägenhet. Designkoncepten avser en portabel display, en webbaserad statistiktjänst samt grafisk förbrukningsinformation på elräkningen. Det övergripande målet med projektet är en minskad och mer medveten elanvändning i flerbostadshus.

    Utvecklingen omfattar displayens och statistiktjänstens funktioner och gränssnitt samt en ändamålsenlig formgivning av den grafiska återkopplingen på elräkningen. Utvärderingen omfattar de boendes användning och upplevelser av de produkter och tjänster som designkoncepten avser. Projektet genomförs i två etapper, varav den första omfattar utvecklingen av ovan nämnda designkoncept och den andra avser utvärderingen av desamma. Föreliggande rapport avser den första etappen, medan den andra redovisas i samband med slutrapporteringen av projektet.

  • 6.
    Bartusch, Cajsa
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Visualisering av elanvändning i flerbostadshus: Slutrapport inom ELAN Etapp III2011Report (Other academic)
    Abstract [sv]

    Elanvändningen i våra bostäder sker vanligtvis utan närmare eftertanke och reflektion. Återkopplingen avseende hushållens individuella elanvändning är i den meningen mycket betydelsefull. I dagsläget är dock den förbrukningsinformation som hushållen har tillgång till mycket begränsad, i synnerhet i flerbostadshus. Syftet med projektet Visualisering av elanvändning i flerbostadshus har varit att utveckla och utvärdera designkoncept för individuell återkoppling till hushåll som bor i lägenhet. Designkoncepten avser en portabel display, en webbaserad statistiktjänst samt grafisk förbrukningsinformation på elräkningen. Det övergripande målet med projektet har varit att bidra till en mer medveten och därmed effektivare elanvändning i flerbostadshus.Utvecklingen har omfattat displayens och statistiktjänstens funktioner och gränssnitt samt en ändamålsenlig formgivning av den grafiska återkopplingen på elräkningen.

    Utvärderingen har omfattat de boendes användning och upplevelser av de produkter och tjänster som designkoncepten avser. Projektet har genomförts i två etapper, varav den första har omfattat utvecklingen av ovan nämnda designkoncept och den andra har avsett utvärderingen av desamma. Föreliggande rapport avser i första hand den andra etappen, medan resultaten av den första har redovisats i sin helhet i en tidigare delrapport; Elforsk rapport 08:18.

    Den trådlösa displayen tillhandahåller framför allt funktioner med mer eller mindre direkt återkoppling, medan statistiktjänsten och i synnerhet den grafiska förbrukningsinformationen i första hand avser uppföljning av den individuella elanvändningen med längre tidsperspektiv. Både displayen och statistiktjänsten erbjuder även möjligheten att göra jämförelser mellan olika tidsperioder och med liknande hushåll. Traditionella stapeldiagram i kombination med förtydligande färgsymbolik har visat sig vara mycket funktionella och har följaktligen använts i flertalet av designkonceptens gränssnitt. Enkelhet och lättillgänglighet har visat sig vara de viktigaste framgångsfaktorerna i samband med återkoppling till elanvändare.

    Den grafiska förbrukningsinformationen på elräkningen har framstått som viktigast i den bemärkelsen att den utgör den återkoppling som når i särklass flest elkonsumenter. Egenskaperna enkelhet och lättillgänglighet har därför en särskilt avgörande betydelse i det här sammanhanget. Ett förhållandevis avskalat designkoncept har således förordats för ändamålet grafisk förbrukningsinformation på fakturan. Tidsupplösningen motsvarar faktureringsperioderna och grafens staplar representerar med andra ord de faktiska och förväntade månadsförbrukningarna under innevarande år samt i jämförande syfte de faktiska månadsförbrukningarna under föregående år.

    Utvecklingen och utvärderingen av en portabel display har omfattat två olika designkoncept: Interactive Institute’s Energy AWARE Clock och ”Ingenjörsdisplayen”. Namnen härstammar från gränssnittens olika utformningar av förbrukningsinformationen, som i jämförande syfte har varit abstrakt men intuitivt tillgänglig respektive konkret och reell. De användartester som har genomförts i hemmiljö tyder därvidlag på att användarna föredrar en kombination av de båda designkoncepten. För en optimal användning av den här produkten krävs en central placering i hemmet, vilket innebär att yttre egenskaper såsom en tilltalande design har visat sig ha stor betydelse för användarna.Den webbaserade statistiktjänsten, som kallas Energiinfo™, utgör den återkoppling som tillhandahåller flest alternativa tidsupplösningar.

    Förbrukningsinformationen som tillhandahålls på månads- och årsbasis har emellertid visat sig vara bäst lämpade för kontroll och uppföljning av hushållets elanvändning, vilka utgör de vanligaste användningsområdena. Användarnas syften är dock för övrigt högst varierande och möjligheten att anpassa förbrukningsinformationen för deras individuella behov har därför visat sig vara mycket betydelsefull i det här sammanhanget.

    Samtliga designkoncept som studien avser har visat sig vara mer eller mindre ändamålsenliga i den bemärkelsen att de i viss mån bidrar till en ökad medvetenhet om hushållets egen elförbrukning samt ett förändrat beteende i syfte att effektivisera densamma. Inget av designkoncepten har dock framstått som viktigare än det andra i det avseendet, utan den förbrukningsinformation som de olika återkopplingsalternativen tillhandahåller kompletterar snarare varandra. Vidare har inget av designkoncepten visat sig vara idealiskt för uppdelningsåterkoppling, vilket innebär information om hur mycket olika hushållsapparater bidrar till den totala elkonsumtionen och tenderar att vara den förbrukningsinformation som hushållen har störst behov av.

  • 7.
    Bartusch, Cajsa
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Larsson, Mikael
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wallin, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wester, Lars
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Potential of hourly settlements in the residential sector of the Swedish electricity market: Estimations of risk reduction and economic result2010In: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 7, no 3, p. 224-240Article in journal (Refereed)
    Abstract [en]

    Increased demand response is essential in order to boost the effectiveness of the Swedish power market. The all-embracing installation of automatic meter reading systems enables power suppliers to introduce hourly settlements in the residential sector. The aim of the study has been to assess the impact of electricity retailers’ physical and financial risk in customer segments with different heating systems as well as to estimate the potential of the electricity contract ”Fixed price with the right to return” in terms of economic consequences and risk management. The results show that households whose main heating system consists of a geothermal heat pump constitute the largest physical price and volume risk of suppliers. The gain of introducing hourly settlements in the residential electricity market has furthermore proven to be manifold from both an economic and risk reducing point of view.

  • 8.
    Bartusch, Cajsa
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wallin, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wester, Lars
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Exploring variance in residential electricity consumption: Household features and building properties2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 92, p. 637-643Article in journal (Refereed)
    Abstract [en]

    Improved means of controlling electricity consumption plays an important part in boosting energy efficiency in the Swedish power market. Developing policy instruments to that end requires more in-depth statistics on electricity use in the residential sector, among other things. The aim of the study has accordingly been to assess the extent of variance in annual electricity consumption in single-family homes as well as to estimate the impact of household features and building properties in this respect using independent samples t-tests and one-way as well as univariate independent samples analyses of variance. Statistically significant variances associated with geographic area, heating system, number of family members, family composition, year of construction, electric water heater and electric underfloor heating have been established. The overall result of the analyses is nevertheless that variance in residential electricity consumption cannot be fully explained by independent variables related to household and building characteristics alone. As for the methodological approach, the results further suggest that methods for statistical analysis of variance are of considerable value in indentifying key indicators for policy update and development.

  • 9.
    Bartusch, Cajsa
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wallin, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Iana, Vassileva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wester, Lars
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Introducing a demand-based electricity distribution tariff in the residential sector: demand response and customer perception2011In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 39, no 9, p. 5008-5025Article in journal (Refereed)
    Abstract [en]

    Increased demand response is essential to fully exploit the Swedish power system, which in turn is an absolute prerequisite for meeting political goals related to energy efficiency and climate change. Demand response programs are, nonetheless, still exceptional in the residential sector of the Swedish electricity market, one contributory factor being lack of knowledge about the extent of the potential gains. In light of these circumstances, this empirical study set out with the intention of estimating the scope of households’ response to, and assessing customers’ perception of, a demand-based time-of-use electricity distribution tariff. The results show that households as a whole have a fairly high opinion of the demand-based tariff and act on its intrinsic price signals by decreasing peak demand in peak periods and shifting electricity use from peak to off-peak periods.

  • 10.
    Benavente, F.
    et al.
    Department of Chemical Engineering, Applied Electrochemistry, KTH Royal Institute of Technology, Stockholm, Sweden.
    Lundblad, A.
    Division of Safety and Transport/Electronics, RISE, Research Institutes of Sweden, Borås, Sweden.
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Department of Chemical Engineering, Energy Processes, KTH Royal Institute of Technology, Sweden.
    Zhang, Y.
    Department of Chemical Engineering, Energy Processes, KTH Royal Institute of Technology, Sweden.
    Cabrera, S.
    Instituto de Investigaciones Químicas, Carrera de Ciencias Químicas, UMSA Universidad Mayor de San Andrés, Bolivia.
    Lindbergh, G.
    Department of Chemical Engineering, Applied Electrochemistry, KTH Royal Institute of Technology, Stockholm, Sweden.
    Photovoltaic/battery system sizing for rural electrification in Bolivia: Considering the suppressed demand effect2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, p. 519-528Article in journal (Refereed)
    Abstract [en]

    Rural electrification programs usually do not consider the impact that the increment of demand has on the reliability of off-grid photovoltaic (PV)/battery systems. Based on meteorological data and electricity consumption profiles from the highlands of Bolivian Altiplano, this paper presents a modelling and simulation framework for analysing the performance and reliability of such systems. Reliability, as loss of power supply probability (LPSP), and cost were calculated using simulated PV power output and battery state of charge profiles. The effect of increasing the suppressed demand (SD) by 20% and 50% was studied to determine how reliable and resilient the system designs are. Simulations were performed for three rural application scenarios: a household, a school, and a health centre. Results for the household and school scenarios indicate that, to overcome the SD effect, it is more cost-effective to increase the PV power rather than to increase the battery capacity. However, with an increased PV-size, the battery ageing rate would be higher since the cycles are performed at high state of charge (SOC). For the health centre application, on the other hand, an increase in battery capacity prevents the risk of electricity blackouts while increasing the energy reliability of the system. These results provide important insights for the application design of off-grid PV-battery systems in rural electrification projects, enabling a more efficient and reliable source of electricity. 

  • 11.
    Bergman, Niklas
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Wahlberg, Simon
    Mälardalen University, School of Business, Society and Engineering.
    Fjärrvärmens konkurrenssituation: En studie av fjärrvärmens konkurrenskraft i Västerås2018Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    District heat is currently more exposed for competition than it has been for several years. Since the mid-1980s, district heat has dominated the heat market, but is now in a tougher competitive situation due to the increasing popularity of heat pumps. This, in combination with energy efficiency, has led to a stagnation of delivered energy. The purpose of the study is to investigate the district heating's current competitive situation in Västerås. This will be investigated based on pricing, performance and paragraphs. In order to get a comprehensive picture of the heat market and to find out what factors customers prioritize, housing companies, house makers and villa owners were interviewed.

    The study's results show that house owners prioritize delivery reliability, followed by economy and environment in the choice of heating method. Actors' views on pricing were different depending on the preferred heating method, where the different views were primarily about the operating and maintenance costs of heat pumps. In order to analyze pricing the life cycle cost was calculated on the basis of real cases. This was done by creating a calculation model in Excel. The result of pricing shows that district heating was the best option for all cases. However, from a new construction perspective, geothermal heat pump for small houses had similar life cycle cost as district heating, while district heating was superior in price for the larger houses. All cases when a customer had change from district heat to heat pumps were unprofitable due to the switching cost that arises.

    Performance was evaluated by the environmental impact and delivery reliability of the methods. The consequential life cycle assessment was used when calculating environmental impact. The result showed that the district heating in Västerås has a positive environmental impact because of the social benefits it provides. Heat pumps had a negative impact on the environment in all cases. The delivery reliability was studied through actors' views in combination with scientific research, which resulted in the view that district heating is better.

    The evaluation of paragraph was limited to Boverket’s building regulations. The competitive situation is currently skewed, where heat pumps have a big advantage as houses can limit their energy efficiency with heat pumps.

    The future of district heating in Västerås is bright. The challenge is to keep their market domination by maintaining a competitive price as the heat market is facing changes with reduced heat demand and tougher competition.

  • 12.
    Blarke, Morten B
    et al.
    Aalborg University.
    Dotzauer, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Intermittency-friendly and high-efficiency cogeneration: Operational optimisation of cogeneration with compression heat pump, flue gas heat recovery, and intermediate cold storage2011In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 36, no 12, p. 6867-6878Article in journal (Refereed)
    Abstract [en]

    This paper develops, implements, and applies a mathematical model for economic unit dispatch for a novel cogeneration concept (CHP-HP-FG-CS (CHP with compression heat pump and cold storage using flue gas heat)) that increases the plant's operational flexibility. The CHP-HP-FG-CS concept is a high-efficiency and widely applicable option in distributed cogeneration better supporting the co-existence between cogenerators and intermittent renewables in the energy system. The concept involves integrating an efficient high-temperature compression heat pump that uses only waste heat recovered from flue gases as low-temperature heat source, and an intermediate cold thermal storage allowing for non-concurrent operation of the cogeneration unit and the heat pump unit. The model is applied for a paradigmatic case study that shows how the integration of a heat pump affects the operational strategy of a cogeneration plant. It is found that CHP-HP-FG-CS offers significant reductions in fuel consumption (-8.9%) and operational production costs (-11.4%). The plant's fuel-to-energy efficiency increases from 88.9 to 95.5%, which is state-of-the-art. The plant's intermittency-friendliness coefficient Rc improves only marginally due to the constrained nature of the low-temperature heat source and the associated small capacity of the heat pump unit. Significant improvements in Rc are found when increasing the heat pump capacity assuming the availability of an unconstrained heat source

  • 13.
    Brandt, Pernilla
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Löving, Therese
    Mälardalen University, School of Business, Society and Engineering.
    Applikation av småskalig värme- och elproduktion: Simulering av anläggningsdrift samt nyttjande av hästgödsel för lokal biogasproduktion vid Sundbyholms travbana2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The global community is facing great challenges as the energy system is transforming towards more reliable, effective, clean and renewable production. Small-scale and micro networks will play an important role in this changeover. Its advantages over today’s large conventional energy systems are their reliability and stability. In small-scale and micro networks, there is usually a variety of production units such as photovoltaic, wind power and micro-combined heat and power (micro-CHP). In this study, a small-scale network with an application of two different types of biogas fueled micro-CHPs is analyzed. The units are a micro gas engine (MGM) and a micro gas turbine (MGT). The application of micro-CHP is validated using a reference facility connected to a small-scale district heating network. The reference facility is a heat production plant at a horse race track outside Eskilstuna, Sweden consisting of an oil boiler, a pellet boiler and a heat storage tank. The potential in replacing the oil boiler with renewable micro-CHP is investigated. A simulation model is built in the software GAMS, using Mixed Integer Linear Programming (MILP) and the solver CPLEX, and the model is simulated using the heat demand from the horse race track. Results from the model validation shows that it is possible for both the MGM or the MGT together with the pellet boiler and the heat storage tank to fulfill the heat demand of the facility. The horse race track handles 4 000 m3 of horse manure annually, which is transported 124 km to a compost treatment facility. Therefore, a general analysis of biogas production from horse manure is conducted in order to investigate the possibilities for better horse manure treatment on site. A calculation for a biogas reactor with a capacity for the maximum biogas requirement of the micro-CHP is implemented. Horse manure is suggested to be co-digested with food waste, in order to provide a higher biogas exchange. The result of a Life Cycle Cost (LCC) analysis indicates difficulties in justifying an investment of a micro-CHP together with a biogas plant at current prices for heat and electricity. The results show that the payback period for the MGM is 7 years which is 2 years shorter than its lifetime and the MGT payback period is 12 year which also is it lifetime. The MGM shows the largest investment potential since it has an investment cost approximately 860 kSEK lower than for the MGT. The MGM also has a slightly higher electrical efficiency which results in higher revenues from produced electricity. The chosen MGM in this study is slightly smaller than the MGT, resulting in a lower biogas demand and a lower investment cost for a biogas plant. A sensitivity analysis shows great impact of the electricity price on the payback period for both types of micro-CHP. The results show that with an electricity price of 280 SEK/MWh, both the MGM and the MGT repays within their lifetime. But since MGM has a higher net present value at all electric prices, is the MGM considered to be a more economical feasible investment.

    What the authors think should be highlighted is also the environmental benefits of more efficient treatment of horse manure at the horse race track together with the possibility of local production of fuel resulting in reduced CO2 emissions by 47 tons/year.

  • 14.
    Bäckström, Mathias
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Hellberg, Anton
    Mälardalen University, School of Business, Society and Engineering.
    UNDERSTANDING THE PRODUCTION BEHAVIOUR OF COMBINED HEAT AND POWER PLANTS: A mathematical programming approach2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates how combined heat and power plants (CHP) produce electricity, with respect to several external factors including outdoor temperature and electricity prices. The purpose is to develop and evaluate a tool, with the aim to increase the understanding of CHP plants electricity production behaviour. This tool resulted in an optimisation model, developed in Python and using the CVXPY package. The objective of the model is to include a system of production units and optimise the production from these by minimising the production costs, while also considering technical constraints. Inspiration for the model was found from a literature review and from interviews with people working in the CHP sector, where the latter also provided historical production data used for validation. When comparing the modelled yearly electricity production with the historical data for the same year, it was found that the model deviated less than 10 percent for the two real district heating systems where the model was implemented. In conclusion, it is seen that the model behaves similar to the actual plants when looking at the electricity production; however, the behaviour of the model is slightly exaggerated with faster changes in the electricity production. Though, the results show that the developed model can be used to enhance the understanding of how CHP plants produce electricity. 

  • 15.
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering.
    PV water pumping systems for grassland and farmland conservation2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Grassland degradation is considered as one of the worst environmental and economic problems in China because of the negative impacts on water and food security. The application of the photovoltaic water pumping (PVWP) technology for irrigation is an innovative and sustainable solution to curb the progress of grassland desertification and to promote the conservation of farmland in remote areas. The combination of PVWP with water saving irrigation techniques and the sustainable management of the water resources enhances the grass productivity enabling to halt wind and rainfall erosion and to provide higher incomes and better living conditions for farmers. PVWP systems have been used for more than 40 years especially for drinking purposes, livestock watering and irrigation in small-medium size applications. Nevertheless, several knowledge gaps still exist and system failures still occur, which are mainly bounded to the system design procedure and optimization. The technical and economic feasibilities related to the system implementation, especially effectiveness and profitability, need to be addressed. Moreover, irrigation in remote areas constrained by availability of water resources has to be investigated for a better understanding of PVWP system integration with the environment and for optimization purposes. This thesis is to bridge the current knowledge gaps, optimize system implementation and prevent system failures 

     

    Validation of the models adopted and optimization of the system on the basis of solar energy resources and exploitable groundwater has been performed for a pilot PVWP system in Inner Mongolia. The match between the water supplied through the pumping system and the grass water demand has been studied, and the effects of pumping on the available resources and the crop productivity have been evaluated. The economic analyses have also been conducted in order to establish the most cost effective solution to provide water for irrigation and to evaluate the project profitability. In addition, the CO2 emission reductions by using PV technology have been assessed as well.

     

    It was found that the proper designed PVWP system represents the best technical and economic solution to provide water for irrigation in the remote areas compared to other water pumping technologies, such as diesel water pumping and wind power water pumping due to the high positive net present values and short payback periods.

  • 16.
    Campana, Pietro Elia
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Olsson, Alexander
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Economic analysis of photovoltaic water pumping irrigation systems2013Conference paper (Refereed)
    Abstract [en]

    Irrigation through photovoltaic water pumping (PVWP) system represents one of sustainable and attractivesolutions regarding the problems related to the Chinese grassland desertification. This paper is to investigatethe economics of PVWP systems taking in consideration of the key parameters affecting the sizing, and furtherthe initial capital cost (ICC), the life cycle cost (LCC) and revenues. In particular photovoltaic (PV) modules cost,availability of the well and of the irrigation system, designing water-head, irrigated area and related waterdemand, fuel price and grass production are investigated for the sensitivity analysis. The possibility ofcombining water pumping with electricity production for maximizing benefits is also discussed. Both PVWP anddiesel water pumping (DWP) systems are compared in terms of ICC and LCC. LCC, sensitivity, break-even point(BEP), net present value (NPV) and payback period (PBP) analyses are used to compare and evaluate theeconomic feasibility of the different alternatives investigated. The results show that the availability of the welland the depth of the ground water resources are the most sensitive parameters affecting the initial capitalcosts whereas the grass production and incentives affect mainly the NPV and PBP. The co-benefits for carbonmitigation and carbon credit trading through implementing photovoltaic water pumping system for the Chinesegrassland are also addressed in this paper.

  • 17.
    Campana, Pietro Elia
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Olsson, Alexander
    Zhang, Chi
    Berretta, Sara
    Hailong, Li
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    On-grid photovoltaic water pumping systems for agricultural purposes: Comparison of the potential benefits under three different incentive schemes2014Conference paper (Other academic)
  • 18.
    Campana, Pietro Elia
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Zhu, Y.
    Chengdu University, China.
    Brugiati, Elena
    Università Degli Studi di Perugia, Italy.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    PV water pumping for irrigation equipped with a novel control system for water savings2014In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, p. 949-952Article in journal (Refereed)
    Abstract [en]

    Typically, PV water pumping (PVWP) systems for irrigation are normally designed based on the worst conditions, such as high water demand and low solar irradiation. Therefore, the installed PVWP systems become oversized in most of time. Since the conventional control systems don't optimize the water supply, the water losses are increased. To remedy the problems related to the operation of the oversized systems, a novel control system is proposed. The control unit interacts between water demand and water supply in order to pump only the amount required by crops. Moreover, the novel control system substitutes the conventional protection approach with a method based on the ground water resources availability and response. The novel control system represents an innovative solution for water savings in PV watering applications.

  • 19.
    Campillo, Javier
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Barberis, Stefano
    University of Genoa, Italy.
    Traverso, Alberto
    University of Genoa, Italy.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Vassileva, Iana
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Open-Source Modelling and Simulation of Microgrids and Active Distribution Networks2015In: Sustainable Places 2015, Conference Proceedings, Sigma Orionis , 2015, p. 91-99Conference paper (Refereed)
    Abstract [en]

    Distributed generation, and active distribution networks constitute an economic and technically viable alternative for reducing green house gases emissions and increase the use of renewable energy sources in local distribution grids. These active networks allow replacing large generators, usually located far from the consumption loads, thus considerably minimizing distribution losses and increase renewable energy penetration. However, designing and successfully controlling these complex networks, becomes a great engineering challenge; most computational modeling and simulation tools available for these systems are either focused on the individual generation components themselves, or the economic dispatch of multiple generators. Moreover, these tools often rely on closed source commercial software that use manufacturers' data for predefining the parameters of the models' components. This approach does not provide enough flexibility to users, since often is not possible to adjust these parameters. This paper presents object- oriented, component-based, open software components for simulating and optimizing the operation of active distribution networks, including multiple distributed generators and energy using the Modelica open-source modeling language. 

  • 20.
    Campillo, Javier
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ralf, Späth
    ABB.
    Smart Homes as Integrated Living Environments2015In: Handbook of Clean Energy Systems: Volume 4 - Intelligent Energy Systems: / [ed] Jinyue Yan, John Wiley & Sons, 2015Chapter in book (Refereed)
  • 21.
    Campillo, Javier
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Vassileva, Iana
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Is real-time electricity pricing suitable for residential users without demand-side management?2016In: Energy Journal, ISSN 0195-6574, E-ISSN 1944-9089, Vol. 109, p. 310-325Article in journal (Refereed)
    Abstract [en]

    The smart metering infrastructure in Sweden allows electricity providers to offer electricity RTP (real time pricing) to homeowners, together with other dynamic pricing contracts across the country. These contracts are supposed to encourage users to shift power consumption during peak hours to help balance the load in the power system. Of all the available contracts in Sweden, monthly-average price holds the largest share, in response to the low electricity prices during the last three years. It is not clear if RTP will become a popular dynamic pricing scheme since daily price fluctuations might keep customers away from this type of contract. Literature review suggests that RTP adoption is only beneficial when combined with the use of customer demand flexibility, but it does not provide enough information about users adopting RTP without changing their electricity usage profile. This paper studies the economic impact if customers would shift to RTP contracts without adopting demand-side management. To achieve this, electricity costs from a large group of households were calculated and compared between both pricing schemes using the hourly consumption data of a 7-year period. Results suggest that the RTP electricity contract offer a considerable economic savings potential even without enabling consumer demand-side management. 

  • 22.
    Campillo, Javier
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering.
    Torstensson, Daniel
    Mälardalen University, School of Business, Society and Engineering.
    Vassileva, Iana
    Facultad de Ingeniería, Universidad Tecnológica de Bolívar, Cartagena, Colomb.
    Energy Demand Model Design for Forecasting Electricity Consumption and Simulating Demand Response Scenarios in Sweden2012In: / [ed] J. Yan, 2012Conference paper (Refereed)
    Abstract [en]

    The introduction of a deregulated power system market and development of smart-metering technologies in Sweden, bring new opportunities for fully exploiting its power system efficiency and reliability, such as price-based demand response (DR) programs at a large scale for household, commercial and industrial users. 

    The deployments of these DR programs require, however, very accurate demand forecasting models. The traditional approach of obtaining the total energy use and peak demand does not offer the required detailed information. This article reviews several methodologies for forecasting electricity consumption from a bottom-up perspective in order to define the required parameters and structure for obtaining an energy model. This model will finally include energy usage data, behavioural parameters obtained from a survey conducted with 5 000 end-users in different Swedish distribution system operators’ areas, and physical conditions for the facilities (internal/external temperatures and insulation materials). This information is provided from previous research studies performed at Mälardalen University and Swedish electric utilities companies. 

    The obtained model should be able to adjust its parameters dynamically in order to simulate several demand-response scenarios based on four different strategies: time of use pricing, use of curtailable/interruptible rates, imposition of penalties for usage beyond predetermined levels, and real time pricing.

  • 23.
    Campillo, Javier
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wallin, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Vassileva, Iana
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Dahlquist, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Electricity Demand Impact from Increased use of Ground Sourced Heat Pumps2012In: IEEE PES Innovative Smart Grid Technologies Conference Europe, 2012, p. Artnr. 6465876-Conference paper (Refereed)
    Abstract [en]

    The use of ground-sourced heat pumps as main heating systems has increased in Sweden in the last fifteen years to the point that it is the country with the highest amount of GSHP in Europe. Heat pumps are chosen by many households due to their economic savings value; In contrast, electricity prices in Sweden have almost doubled since 2006, threatening their economic benefits. It is therefore, essential to understand GSHPs impact on the user´s electricity consumption and provide suitable demand-response programs that could help develop a model capable of forecasting consumption and provide decision support information to make the best use of the technology. This paper analyses questionnaire surveys and consumption patterns were evaluated for 322 households with installed GSHPs and different pricing schemes in order to increase the understanding of mass use of this type of heating system.

  • 24.
    Dahlquist, Erik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Mirmoshtaghi, Guilnaz
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Larsson, Eva K.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Engvall, K.
    KTH Royal Institute of Technology, Stockholm, Sweden .
    Liliedahl, T.
    KTH Royal Institute of Technology, Stockholm, Sweden .
    Dong, C.
    North China Electric Power University, Beijing, China.
    Hu, X.
    North China Electric Power University, Beijing, China.
    Lu, Q.
    North China Electric Power University, Beijing, China.
    Modelling and Simulation of Biomass Conversion Processes2013In: Proceedings - 8th EUROSIM Congress on Modelling and Simulation, EUROSIM 2013, 2013Conference paper (Refereed)
    Abstract [en]

    By utilizing biomass gasification, the energy contentof the biomass can be utilized to produce gas to be used forcogeneration of heat and power as well as other energy carrierssuch as fuels for vehicles. The concept is suitable forapplication to existing CHP plants as well as for utilizing spentliqour in small scale pulp and paper mills. The introductionwould enable flexible energy utilization, use of problematicfuels as well as protects the environment by e.g. avoiding therelease of toxic substances. In this paper, the possibilities todevelop this concept is discussed. In this paper we comparedifferent gasification processes with respect to what gas qualitywe get, and how the gasification can be modelled usingdifferent modelling approaches, and how these can becombined. Results from simulations are compared toexperimental results from pilot plant operations in differentscales and with different processes like CFB and BFBTechnologies, athmospheric and pressurized, and using steam,air and oxygen as oxidizing media.

  • 25.
    Dahlquist, Erik
    et al.
    Mälardalen University, Department of Public Technology.
    Thorin, Eva
    Mälardalen University, Department of Public Technology.
    Yan, Jinyue
    Mälardalen University, Department of Public Technology.
    Alternative Pathways to a fossil-fuel free energy system in the Mälardalen region of Sweden2006In: Proceedings of the Second International Green Energy Conference, 2006, 2006, p. 822-830Conference paper (Other academic)
    Abstract [en]

    This paper presents a study on alternative pathways to a fossil-fuel free regional energy system in the Mälardalen region of Sweden with a population of 3 million inhabitants. We describe and address how the region can be made independent of fossil fuels by integration of resource management, technology advances, and behavior change in energy use. First we investigate the consumption pattern of the inhabitants. Then we study what resources are available, and how these can be used to fulfill the different demands. If we just use the resources in a pattern of business as usual today without changing the behavior, the balance between demands and resources is difficult to reach. By combining a slightly different behavior and a change of crops it could be possible to fulfill the needs. Some advanced technological solutions have also been proposed. For example, dedicated biomass energy plants such as fodder sugar beats can be used for ethanol production. Also Salix, straw, hemp and some cereals can be used and the residues can be gasified to produce dimethylether (DME), which is good as a replacement for diesel fuel. Still the fuel demand for transport is high, and the vehicle weight could be further reduced. For example, by going back to the car size we had only ten years ago the weight would be 25-30 % less, and fuel consumption would be at least 15 % lower. With diesel engines instead of Otto-engines the fuel consumption could be reduced by 35 %, and with hybrid technology additional 20% fuel reduction could be gained. Improved public transportation will also give a positive effect especially for those commuting between the larger cities and between the cities and the suburbs. The results of our calculations show that it would be possible to accomplish a fossil-free energy system in the Mälardalen region. The results of this study are important since it shows that an energy balance without fossil fuels could be possible for an area with a population in the order of 3 million people, which would also be valuable in studies of other areas in the world.

  • 26.
    Dahlquist, Erik
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Vassileva, Iana
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Wallin, Fredrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    How to save energy to reach a balance between production and consumptionof heat, electricity and fuels for vehicles2012In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 46, no 1, p. 16-20Article in journal (Refereed)
    Abstract [en]

    There is a potential to utilize a significant amount of renewable energy in Sweden and European union(EU). Biomass can fulfil some 8500e12,500 TW h/y in EU, while the total utilization was 16,084 TW h/y2009. Even though there is a significant amount of wind power, hydro power and potentially also solarpower, it still is most economical to reduce the consumption of heat, electricity and fuels for vehicles. Asaved kWh is normally cheaper than to produce one extra. In this paper different opportunities for savingenergy will be discussed. This includes manufacturing industries, process industries, power plants andenergy systems including distribution of power and smart grids, food production and transportation.There is also a major potential to save energy in buildings, both in the north where it is cold, and in thesouth where it can be very hot summer time. Here the potential is to avoid cooling instead. Technicalsolutions as well as economic incentives are covered. Environmental aspects are addressed, so that thesolutions will be long term sustainable.

  • 27.
    Dai, B.
    et al.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Qi, H.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Liu, S.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Ma, M.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Zhong, Z.
    Foreign Economic Cooperation Office, Ministry of Ecology and Environment of the People's Republic of China, Beijing, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Song, M.
    Department of Human and Engineered Environmental Studies, The University of Tokyo, Chiba, Japan.
    Sun, Z.
    Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China.
    Evaluation of transcritical CO 2 heat pump system integrated with mechanical subcooling by utilizing energy, exergy and economic methodologies for residential heating2019In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 192, p. 202-220Article in journal (Refereed)
    Abstract [en]

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

  • 28.
    Daraei, Mahsa
    Mälardalen University, School of Business, Society and Engineering.
    Evaluation and prediction of wood properties in pulp and paper production: Estimation of wood chemical properties and pulping results using Near Infrared Spectroscopy: A case study in BillerudKorsnäs in Gävle2016Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Near Infrared spectroscopy has been recently applied in predicting the different materials especially chemical properties of raw wood used in the pulp and paper mills. In this research, the main goal was to estimate wood chemical properties in the chemical pulping at BillerudKorsnäs mill in Gävle. In fact, the quantity of moisture and lignin was measured using a standard method in the laboratory. Then, with near infrared spectroscopy (NIR) data from solid wood, a model was developed to predict moisture and lignin content in the wood chips. Moreover, the yield of digesting process as well as pulp Kappa value were analyzed for the samples taken from the mill.Good calibration models were separately created for Acid Insoluble Lignin (AIL), Total Lignin, Pulp Yield, and Kappa number of pulp using Orthogonal Signal Correction (OSC) treated NIR spectra with the R-Square values of 0.92, 0.89, 0.85, and 0.99, respectively. The model developed for moisture content showed low R-Square value of 0.52, which indicates some over or under estimation in prediction and high calibration errors. So, it cannot be reliably used for prediction. Moreover, Acid Soluble Lignin (ASL) calibration results with R-Square value of 0.077 were poorly correlated with the laboratory measured values.Based on the results, the OSC treated NIR spectra from raw solid wood can be used to estimate AIL and total lignin content as well as pulp yield and Kappa number. These models could be applied to the fiber lines 1 and 2 at the mill to control the pulping process efficiently and increase the pulp quality. However, the reliability of them needs to be analyzed before application.

  • 29.
    Daraei, Mahsa
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Production planning of CHP plants integrated with bioethanol production and local renewables2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

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

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

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

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

    The full text will be freely available from 2019-11-25 08:00
  • 30.
    Daraei, Mahsa
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dotzauer, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Evaluation of potential fossil fuel free energy system: Scenarios for optimization of a regional integrated system2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, p. 964-970Article in journal (Refereed)
    Abstract [en]

    Population growth and urbanization have led to increases in energy demand and consequently, greenhouse gas emissions. Therefore, the availability of the fossil fuel as the main source of energy supply has been changed. Utilization of renewable resources including solar, wind, and hydropower together with distributed energy systems could eliminate the dependency on fossil fuel energy sources. In this paper, energy use and supply trends have been studied for the Counties of Västmanland and Södermanland in Sweden in order to develop a scenario for the regional energy system in 2030. The aim is to use the scenario for evaluation of the impacts of regional renewable energy resources on the production planning of CHP plants. The scenario shows that there is not enough potential for electricity production from renewable resources such as solar, wind, and hydropower to fulfill the estimated demand in 2030. Around 75% of electricity needs in Västmanland and 89% of power demands in Södermanland need to be met by imported electricity to these regions. Efficiency improvements and a more complex energy system integrating also with other energy resources like biomass, waste and industrial waste heat are necessary to develop a sustainable energy system.

  • 31.
    den Boer, Jan
    et al.
    WAMECO S.C., ul. Malinowa 7, 55-002 Kamieniec Wrocławski, Poland.
    den Boer, Emilia
    Institute of Environment Protection Engineering, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
    Szpadt, Ryszard
    Institute of Environment Protection Engineering, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
    Łukaszewska, Agnieszka
    Marshal Office of Lower Silesia, Wybrzeże Słowackiego 12-14, 50-411 Wrocław, Poland.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    ENERGY POTENTIAL FROM RESIDUES IN NORTHERN CENTRAL EUROPEAN REGIONS2012Conference paper (Other academic)
    Abstract [en]

    In this paper the results of a study on the energy potential of residual materials in 5 regions in the Northern Central European area are presented. The highest potential for waste-to-energy is provided by the incineration of municipal residual waste and the digestion of manure. Related to the number of inhabitants, the potential is the highest in North Savo, whereas the current utilisation is by far the highest in the County of Västmanland. The total potential of waste-to-energy for the considered regions is the highest for Western Lithuania at app. 7%, with the other regions varying between 2,5 and 4% of the total primary energy use. The following waste-to-energy installations should be planned: waste incinerators (Estonia, Western Lithuania and Lower Silesia); energy recovery from waste derived fuels (North Savo, Lower Silesia and the County of Västmanland); anaerobic digestion of biodegradable part of municipal waste and of agricultural waste and by-products (Lower Silesia) as well as sewage sludge drying in Western Lithuania and Lower Silesia.

  • 32.
    Desideri, U
    et al.
    Univ Perugia, Italy.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Clean energy technologies and systems for a sustainable world2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, no SI, p. 1-4Article in journal (Refereed)
  • 33.
    Eklund, Malin
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Habib, Mariana
    Mälardalen University, School of Business, Society and Engineering.
    Energikartläggning av två skolor i Västerås: Undersökning av möjligheter till effektivare energianvändning på Rönnbyskolan och Rönnby förskola2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Rönnbyskolan and Rönnby förskola is a school area situated in the city of Västerås, Sweden that consist of a total of five buildings. The main buildings are built in 1973 which makes their energy use of interest. Due to the individual goals for Sweden to lower its energy use by 2020, the city of Västerås has begun an energy efficiency process to reduce energy use in potential buildings. In this degree project, a survey of the buildings’ energy consumption has been reviewed and possible energy reduction methods have been presented. This was made by studying the surveys of the buildings ventilation systems, the heating systems, the envelope and the buildings application by taking measurements. The results from the measurements have been studied and confirmed with the literature study and suggestions of energy effective solutions are presented based on energy calculations. Based on the results, four different technological installations and four building engineering actions have been evaluated. The calculations were supplemented with a model built and simulated in the simulation tool IDA ICE. Economical aspects were taken into account, which shows the connection between energy savings and economic profit. Due to high investment costs, only a few actions were cost effective. The result of the study showed that the buildings can reduce their energy consumption by 17 % or 34 kWh/ m2, year using the measures that turned out profitable.

  • 34.
    Ekman, Peter
    et al.
    Mälardalen University, School of Business, Society and Engineering, Industrial Economics and Organisation.
    Röndell, Jimmie
    Mälardalen University, School of Business, Society and Engineering, Industrial Economics and Organisation.
    Yang, Ying
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Exploring smart cities and market transformations from a service-dominant logic perspective2019In: Sustainable cities and society, ISSN 2210-6707, Vol. 51, article id 101731Article in journal (Refereed)
    Abstract [en]

    This study addresses the emergence of new actors and their roles in the transformation of smart cities. By building on a Service-Dominant logic perspective, the study capture how smart city transformation is closely related to a smart market transformation. While prior conceptualizations of markets have followed a linear supply-demand structure, the new market conceptualization can be described as a service ecosystem. The study empirically follows the increased use of renewable energy, such as photovoltaic (PV) systems and their related services, as they are incorporated into smart cities. The results reveal that the overall interaction level among the involved actors increases as the energy market changes from a linear to a networked logic. This transition impacts the market's information quality and, subsequently, the actors’ level of required knowledge. The study shows that even if the prevailing actors become more informed, information needs to be ‘translated’ into ‘knowledge-in-context’ to become a valuable resource. Thus, the resulting service ecosystem demands a complementary actor that requires the role of a knowledge broker to function. The paper describes the mechanisms behind this smart city transformation and clarifies the broker functions.

  • 35.
    Eld, Jonas
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Melin, Jens
    Mälardalen University, School of Business, Society and Engineering.
    Test Grids for Reliability analysis: Analysing interruptions and developing test grids based on Mälarenergi Elnät distribution grid2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this degree project is to examine power outages that has occurred during the years 2009 and 2016 on Mälarenergi Elnät distribution grid. Interruptions that has occurred on 10 kV voltage level and on overhead lines or underground cable was examined. The examined interruptions are based on the DARWin data from Mälarenergi Elnät. The examined interruptions resulted in four different test grids. Test grid A are overhead line grid in rural area, test grid B are mixed grid in rural area, test grid C are underground cable grid in semi urban area and test grid D are underground cable grid in urban area. Test grid C and D which have the highest customer density were then used for reliability analysis. The reliability analysis was performed using Microsoft Excel. The main focus for the reliability analysis were the impact of different sectioning times. Another focus for the reliability analysis was introducing breakers at key-points in test grid C. The primarily cause of interruptions on overhead line grids are weather related events and on underground cable grids it is digging and fabrication or material errors. It is concluded that with quicker sectioning times, the reliability of the grid increases linearly. The introduction of breakers at key-points in the grid results in increased reliability.

  • 36.
    Ericson, Eva
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology. KTH.
    Exploring the possibility of using a simple neural network for the prediction of biogas production of a solid waste digester2010Conference paper (Refereed)
  • 37.
    Eskilsson, Anton
    Mälardalen University, School of Business, Society and Engineering.
    Energy flow mapping of a sports facility: Energy flow mapping and suitable key performance indicator formulation for Rocklunda sports facility2017Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 38.
    Farahmand Ghaffarpour, Mehdi
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ros, Henrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Integration of thermochemical heat storage with a municipal district heating system: In future scenario with large variations in electricity price2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates the feasibility and benefits of integrating Thermochemical heat Storage (THS) into a CHP (Combined Heat and Power) plant. A case study is done for the CHP-plant in Sala, Sweden, with a maximum heat output of 20.9 MW and maximum electricity output of 9.6 MW. The THS type considered is calcium oxide in a hydroxide system. The fluctuations in electricity price for years 2020, 2030 and 2040 are considered and low-price electricity is used as a charging source for THS. During charging the superheated steam (endothermic reaction) is used to cover some of the district heating demand. The high temperature discharge from the THS is used as reheat in the Rankine cycle. The operations are modeled in Ebsilon and optimization is done in MATLAB using genetic algorithm with the objective to achieve maximum annual revenue. The results suggest that it is not feasible to introduce THS with electricity as a charging source in year 2020, but in 2030 and 2040 THS shows promising potential. The biggest increase in revenue comes from reduced fuel consumption, and, to a lesser extent, increased income from electricity. It is concluded that Calcium hydroxide is a promising candidate for integration into CHP during large electricity price fluctuation. The main drivers for the feasibility of this combination are high fuel price and large fluctuations of electricity price.

  • 39.
    Fiedler, Frank
    et al.
    Mälardalen University, Department of Public Technology. Dalarna University College, Sweden.
    Bales, C
    Dalarna University College, Sweden.
    Persson, T
    Dalarna University College, Sweden.
    Optimisation method for solar heating systems in combination with pellet boilers/stove2007In: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 4, no 3, p. 325-337Article in journal (Refereed)
    Abstract [en]

    n this study, an optimisation method for the design of combined solar and pellet heating systems is presented and evaluated. The paper describes the steps of the method by applying it to an example system. The objective of the optimisation was to find the design parameters that give the lowest auxiliary energy (pellet fuel + auxiliary electricity) and carbon monoxide (CO) emissions for a system with a typical load: a single family house in Sweden. Weighting factors have been used for the auxiliary energy use and CO emissions to give a combined objective function. Different weighting factors were tested. The results show that extreme weighting factors lead to their own minima. However, it was possible to find factors that ensure low values for both auxiliary energy and CO emissions, and suitable weighting factors are suggested.

  • 40.
    Fiedler, Frank
    et al.
    Dalarna University College, Sweden.
    Nordlander, S
    Dalarna University College, Sweden.
    Persson, T
    Dalarna University College, Sweden.
    Bales, C
    Dalarna University College, Sweden.
    Thermal performance of combined solar and pellet heating systems2006In: Renewable Energy, ISSN 0960-1481, Vol. 31, no 1, p. 73-88Article in journal (Refereed)
    Abstract [en]

    Various pellet heating systems are marketed in Sweden, some of them in combination with a solar heating system. Several types of pellet heating units are available and can be used for a combined system. This article compares four typical combined solar and pellet heating systems. System 1 and 2 with a pellet stove, system 3 with a store integrated pellet burner and system 4 with a pellet boiler. The often lower efficiency of pellet heaters compared to oil or gas heaters increases the final energy demand. Consequently, heat losses of the various systems have been studied. The systems have been modeled in TRNSYS and simulated with parameters identified from measurements. For almost all systems the flue gas losses are the main heat losses except for system 3 where store heat losses prevail. Relevant are also the heat losses of the burner and the boiler to the ambient. Significant leakage losses are noticed for system 3 and 4. For buildings with an open internal design system I is the most efficient solution. Other buildings should preferably apply system 2 or 3. The right choice of the system depends also on whether the heater is placed inside or outside of the heated area. Unlike the expectations and results from other studies, the operation of the pellet heaters with modulating combustion power is not necessarily improving the performance. A large potential for system optimisation exists for all studied systems, which when applied could alter the relative merits of the different system types.

  • 41.
    Ghaviha, Nima
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bohlin, Markus
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Optimal Control of a Battery Train Using Dynamic Programming2015Conference paper (Other academic)
    Abstract [en]

    Electric propulsion system in trains has the highest efficiency compared to other propulsion systems (i.e. steam and diesel). Still, electric trains are not used on all the routes, due to the high setup and maintenance cost of the catenary system. Energy storage technologies and the battery driven trains however, make it possible to have the electric trains on the non-electrified routes as well. High energy consumption of the electric trains, makes the energy management of such trains crucial to get the best use of the energy storage device. This paper suggests an algorithm for the optimal control of the catenary free operation of an electric train equipped with an onboard energy storage device. The algorithm is based on the discrete dynamic programming and Bellman’s backward approach. The objective function is to minimize the energy consumption, i.e. having the maximum battery level left at the end of the trip. The constraints are the trip time, battery capacity, local speed limits and limitations on the traction motor. Time is the independent variable and distance, velocity and battery level are the state variables. All of the four variables are discretized which results in some inaccuracy in the calculations, which is discussed in the paper. The train model and the algorithm are based on the equations of motion which makes the model adjustable for all sorts of electric trains and energy storage devices. Moreover, any type of electrical constraints such as the ones regarding the voltage output of the energy storage device or the power output can be enforced easily, due to the nature of the dynamic programming. 

  • 42.
    Ghaviha, Nima
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bohlin, Markus
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Wallin, Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Optimal Control of an EMU Using Dynamic Programming and Tractive Effort as the Control Variable2015In: Proceedings of the 56th SIMS, Linköping University Electronic Press, Linköpings universitet, 2015, p. 377-382Conference paper (Refereed)
    Abstract [en]

    Problem of optimal train control with the aim of minimizing energy consumption is one of the old optimal control problems. During last decades different solutions have been suggested based on different optimization techniques, each including a certain number of constraints or different train configurations, one being the control on the tractive effort available from traction motor. The problem is previously solved using dynamic programming for trains with continuous tractive effort, in which velocity was assumed to be the control variable. The paper at hand presents a solution based on dynamic programming for solving the problem for trains with discrete tractive effort. In this approach, tractive effort is assumed to be the control variable. Moreover a short comparison is made between two approaches regarding accuracy and ease of application in a driver advisory system.

  • 43.
    Ghaviha, Nima
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Campillo, Javier
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Bohlin, Markus
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Review of Application of Energy Storage Devices in Railway Transportation2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 4561-4568Article in journal (Refereed)
    Abstract [en]

    Regenerative braking is one of the main reasons behind the high levels of energy efficiency achieved in railway electric traction systems. During regenerative braking, the traction motor acts as a generator and restores part of the kinetic energy into electrical energy. To use this energy, it should be either fed back to the power grid or stored on an energy storage system for later use. This paper reviews the application of energy storage devices used in railway systems for increasing the effectiveness of regenerative brakes. Three main storage devices are reviewed in this paper: batteries, supercapacitors and flywheels. Furthermore, two main challenges in application of energy storage systems are briefly discussed. 

  • 44.
    Gibrael, Nemir
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Hassan, Hamse
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    HYDROGEN-FIRED GAS TURBINE FOR POWER GENERATION WITH EXHAUST GAS RECIRCULATION: Emission and economic evaluation of pure hydrogen compare to natural gas2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The member states of European Union aim to promote the reduction of harmful emissions. Emissions from combustion processes cause effects on human health and pose environmental issues, for example by increasing greenhouse effect. There are two ways to reduce emissions; one is to promote renewable energy sources and the other to utilize more effectively the available fossil fuels until a long-term solution is available. Hence, it is necessary to strive for CO2 mitigation technologies applied to fossil fuels. Low natural gas prices together with high energy efficiency have made gas turbines popular in the energy market. But, gas turbine fired with natural gas come along with emissions of CO2, NOx and CO. However, these disadvantages can be eliminated by using gas turbine with precombustion CO2 capture, separating carbon from the fuel by using fuel reforming process and feeding pure hydrogen as a fuel. Hydrogen fired gas turbines are used in two applications such as a gas turbine with pre-combustion CO2 capture and for renewable power plants where hydrogen is stored in case as a backup plan. Although the CO2 emissions are reduced in a hydrogen fired gas turbine with a pre-combustion CO2 capture, there are still several challenges such as high flame temperatures resulting in production of thermal NOx. This project suggests a method for application of hydrogen fired gas turbine, using exhaust gas recirculation to reduce flame temperature and thus reducing thermal NOx. A NOx emission model for a hydrogen-fired gas turbine was built from literature data and used to select the best operating conditions for the plant. In addition, the economic benefits of switching from natural gas to pure hydrogen are reported. For the techno-economic analysis, investment costs and operating costs were taken from the literature, and an economic model was developed. To provide sensitivity analysis for the techno-economic calculation, three cases were studied. Literature review was carried out on several journal articles and websites to gain understanding on hydrogen and natural gas fired gas turbines. Results showed that, in the current state, pure hydrogen has high delivery cost both in the US and Europe. While it’s easy to access natural gas at low cost, therefore in the current state gas turbine fired with natural gas are more profitable than hydrogen fired gas turbine. But, if targeted hydrogen prices are reached while fuel reforming process technology are developed in the coming future the hydrogen fired gas turbine will compete seriously with natural gas.

  • 45.
    Guezgouz, M.
    et al.
    Department of Electrical Engineering, Mostaganem University, Mostaganem, Algeria.
    Jurasz, Jakob
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Faculty of Management, Department of Engineering Management, AGH University.,Cracow, Poland.
    Bekkouche, B.
    Department of Electrical Engineering, Mostaganem University, Mostaganem, Algeria.
    Ma, T.
    School of Mechanical Engineering, Shanghai Jiao Tong University, China.
    Javed, M. S.
    School of Mechanical Engineering, Shanghai Jiao Tong University, China.
    Kies, A.
    Frankfurt Institute for Advanced Studies, Goethe University Frankfurt, Frankfurt am Main, Germany.
    Optimal hybrid pumped hydro-battery storage scheme for off-grid renewable energy systems2019In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 199, article id 112046Article in journal (Refereed)
    Abstract [en]

    The development of energy storage systems paves the way towards a high integration of renewable energy sources in the electricity generation sector. Considering above, this paper introduces a new energy management strategy to efficiently coordinate a hybrid energy storage system based on pumped hydro storage (long term bulk storage) with batteries (short term, more flexible). For the purpose of this analysis, hourly time series of irradiation, wind speed, temperature and real measured load (characteristic for farmstead) covering one year were gathered for the selected site in Algeria. The optimal size of the system is determined based on a multi-objective optimization using a grey wolf optimizer implemented in MATLAB software. The results indicate that the hybrid storage system enables achieving higher reliability at lower cost in comparison to a system with single storage technology. The use of hybrid storage also reduces the curtailment of renewable generation. Further findings reveal that the cost of an optimal energy supply system with 97.5% reliability is 0.162 €/kWh, 0.207 €/kWh and 1.462 €/kWh for hybrid storage, battery and pumped storage, respectively. However, sensitivity analysis shows that the optimal hybrid storage configuration is less resilient when changes in irradiation/temperature/load are considered. This indicates that special actions (upscale of installed power) must be undertaken to avoid lower performance of hybrid storage systems. In summary, the hybrid storage system seems to be better sized for consideration in optimized solar/wind conditions, but by avoiding oversizing they are less resilient to future potential changes in renewable energy availability.

  • 46.
    Guziana, Bozena
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Lindmark, Johan
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Thorin, Eva
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Belous, Olga
    Klaipeda University.
    den Boer, Emilia
    Institute of Environment Protection Engineering, Wrocław University of Technology.
    MANUAL FOR SORTING OF WASTE FOR WASTE-TO-ENERGY SYSTEMS2011Report (Other (popular science, discussion, etc.))
  • 47.
    Hassling, Andreas
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Flink, Simon
    Mälardalen University, School of Business, Society and Engineering.
    SYSTEM IDENTIFICATION OF A WASTE-FIRED CFB BOILER: Using Principal Component Analysis (PCA) and Partial Least Squares Regression modeling (PLS-R)2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Heat and electricity production along with waste management are two modern day challenges for society. One of the possible solution to both of them is the incineration of household waste to produce heat and electricity. Incineration is a waste-to-energy treatment process, which can reduce the need for landfills and save the use of more valuable fuels, thereby conserving natural resources. This report/paper investigates the performance and emissions of a municipal solid waste (MSW) fueled industrial boiler by performing a system identification analysis using Principle Component Analysis (PCA) and Partial Least Squares Regression (PLS-R) modeling. The boiler is located in Västerås, Sweden and has a maximum capacity of 167MW. It produces heat and electricity for the city of Västerås and is operated by Mälarenergi AB. A dataset containing 148 different boilers variables, measured with a one hour interval over 2 years, was used for the system identification analysis. The dataset was visually inspected to remove obvious outliers before beginning the analysis using a multivariate data analysis software called The Unscrambler X (Version 10.3, CAMO Software, Norway). Correlations found using PCA was taken in account during the PLSR modelling where models were created for one response each. Some variables had an unexpected impact on the models while others were fully logical regarding combustion theory. Results found during the system analysis process are regarded as reliable. Any errors may be due to outlier data points and model inadequacies.

  • 48.
    Heidari, Shayan
    Mälardalen University, School of Business, Society and Engineering, Industrial Economics and Organisation.
    Economic Modelling of Floating Offshore Wind Power: Calculation of Levelized Cost of Energy2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Floating offshore wind power is a relatively new technology that enables wind turbines to float above the sea level, tied by anchors at the seabed. The purpose of this work is to develop an economic model for the technology in order to calculate the total cost of a planned wind farm. Cost data are retrieved from reports and academic journals available online. Based on these data, a model in Microsoft Excel is developed which calculates the Levelized cost of energy (LCOE) for floating wind power plants as a function of several input values. As an addition to this model, financing offshore projects are described using literature study and by doing interviews with three major companies, currently investing in offshore wind. As a result, the model allows the user to calculate Capital expenditures, Operating expenditures and LCOE for projects at any given size and at any given site. The current LCOE for a large floating offshore wind farm is indicated to be in the range of 138-147 £/MWh. The outline from interviews was that today there is no shortage of capital for funding wind projects. However, in order to attract capital, the governmental regulatory of that market has to be suitable since it has a crucial impact on price risks of a project.

  • 49.
    Hennessy, Jay
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. RISE Research Institutes of Sweden AB.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Mälardalen University, School of Innovation, Design and Engineering.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Räftegård, Oskar
    RISE Research Institutes of Sweden.
    Economic feasibility of commercial heat-to-power technologies suitable for use in district heating networks2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, p. 1721-1727, article id EGYPRO33942Article in journal (Refereed)
    Abstract [en]

    Recent improvements in heat-to-power (HtP) technologies have led to an increase in efficiency at lower temperatures and lower cost. HtP is used extensively in power generation via the steam Rankine cycle, but so far has not been used in district heating (DH). The aim of the study is to analyze the economic feasibility of using HtP technologies in a DH network. This is achieved by establishing suitable technologies and calculating the levelized cost of electricity (LCOE) under conditions that may be found in DH. The result, for the vendors, temperatures and assumptions considered, is a range of 25–292 €/MWh, excluding the cost of heat. The breadth of this range in part reflects the importance of selecting appropriate products to match the heat source temperature.

  • 50.
    Henningsson, Joakim
    Mälardalen University, School of Business, Society and Engineering.
    Jämförelse av uppvärmningssystem för småhus: Undersökning av fjärrvärme och värmepumpar på ett hus med egenskaper och prestanda baserade på svenska genomsnittliga värden2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report was written as an examination thesis at Mälardalen University in Västerås, Sweden. The subject of the report is to research whether a theoretical single-family home with already installed district heating system for heating and hot water supply should keep it, replace it with a geothermal heat pump or keep it and use it in combination with a smaller air to water heat pump. The report is uses data from the Swedish government institute of Boverket (Literally: Living institute), along with other sources, to construct a model of an average Swedish house and simulate it in the energy simulation program IDA-ICE. This simulation yielded the data needed to conclude which system would be the cheapest in the long run. Thereafter LCC calculations on said data was used to the determine the cost over a 20-year period for the given systems. The report concludes that the model corresponds with the results from Boverket and is therefore an accurate representation of an average single-family home and that the district heating should be replaced with a geothermal heat pump.

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