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  • 201. Faure-Schuyer, A.
    et al.
    Welsch, Manuel
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Pye, S.
    European Energy Policy Objectives2017Inngår i: Europe's Energy Transition: Insights for Policy Making, Elsevier, 2017, s. 31-39Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Europe is on track to achieve the targets it set out for 2020 in terms of share of renewables, greenhouse gas emission reductions, and energy-efficiency efforts. Apart from a decline in consumption due to the 2007-12 financial crises, this apparent success relies on national interventions such as feed-in tariff support schemes. With the decision of the antitrust authorities to move from regulated support to market-based remuneration schemes, the pace of development of renewables is more uncertain. At the same time, significant low-carbon investments are needed to meet the increasingly ambitious energy and climate change targets for 2030 and 2050. This chapter presents an overview of related policy developments, assesses the level of progress towards achieving these targets and present associated barriers. It concludes by discussing the recent evolution of energy prices in the European Union and the challenges related to the Energy Union project.

  • 202. Faure-Schuyer, A.
    et al.
    Welsch, Manuel
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Pye, S.
    Introduction: Europe as a Consuming Region2017Inngår i: Europe's Energy Transition: Insights for Policy Making, Elsevier, 2017, s. 23-24Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Europe is one of the largest energy-consuming regions in the world, relying heavily on fossil fuel imports. This requires the EU to pursue an active policy to ensure security of supply. The challenges are particularly acute in the context of the transformation of the EU's energy systems to meet the 2050 climate change targets. This introductory chapter sets the scene for and presents the outline of the following chapters.

  • 203. Faure-Schuyer, A.
    et al.
    Welsch, Manuel
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Pye, S.
    The European Union on the Global Scene-A Snapshot2017Inngår i: Europe's Energy Transition: Insights for Policy Making, Elsevier, 2017, s. 25-30Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The European Union stand as the world's fourth largest energy-consuming region. Despite the growing share of renewables, its energy supply mix remains dominated by fossil fuels. This chapter presents a statistical overview of the structure and dynamic of the EU's primary energy supply and demand. For a number of Member States, alleviating external energy dependency remains a key concern.

  • 204.
    Fernández Martínez, Alberto
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Huang, Yalin
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Söder, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Distribution network planning with a large amount of small scale photovoltaic power2013Inngår i: 2013 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC), IEEE Computer Society, 2013, s. 1-6Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a new method to assist distribution system operators assessing the capacity of each bus for connecting more photovoltaic power in a low voltage distribution network. The developed method takes the uncertainties from load and generation into account. Moreover, it applies probabilistic voltage limits in the assessment process. An improved linear power flow analysis is used in the process. Furthermore, a case study in a Swedish low voltage network is discussed to apply the proposed method on assessing the maximum photovoltaic peak power that can be installed into a distribution network without violating probabilistic voltage limits. A comparison between deterministic approach and probabilistic approach is also performed.

  • 205. Fikari, Stamatia Gkiala
    et al.
    Ghaem Sigarchian, Sara
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Chamorro, Harold R.
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Modeling and Simulation of an Autonomous Hybrid Power System2017Inngår i: 2017 52nd International Universities Power Engineering Conference (UPEC), IEEE, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Renewable energy sources contribute to overcome the problem of environmental pollution and secure the energy independency every country needs, while at the same time the autonomous microgrids can improve the electrification rates of poorer countries. In this article, the modeling process and operation of an autonomous hybrid power system are studied for a hypothetical case study of electrification of a remote village of 100 inhabitants in Kenya. The microgrid consists of photovoltaics, wind turbine, batteries, diesel genset, basic loads of different priorities, water pumping and purification load. The system is modeled in Simulink MATLAB and is simulated in terms of power management. The primary load is categorized in different priorities, while water pumping and purification is used as deferrable load. The "load following" dispatch strategy is adopted. The outputs of the model are the power produced by the various sources and the power consumed by all loads during the simulation time, as well as the produced and consumed energy, information on the battery operation and the dumped power or the power shortage. Both the microgrid's operation and the performance of the dispatch strategy are evaluated considering the level on which the citizens' energy needs are covered and the efficient management of the produced energy. Managing the extra power or tackling the deficit of power in the system are the key issues to be addressed. After all, the model represents reliably the behavior of the microgrid and several improving actions are suggested, based on the results analysis.

  • 206.
    Firmansyah, Husni
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Tan, Yuting
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Yan, Jinyue
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Power and methanol production from biomass combined with solar and wind energy: analysis and comparison2018Inngår i: RENEWABLE ENERGY INTEGRATION WITH MINI/MICROGRID / [ed] Yan, J Wang, C Yu, J Jia, H Wu, J Xu, T Zhang, Y, ELSEVIER SCIENCE BV , 2018, s. 576-581Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study addresses the techno-economic analysis and comparison of systems for power and methanol production from biomass combined with solar and wind energy, from both technical and economic perspectives. Three different systems, based on Integrated Gasification Combined-Cycle (IGCC), Oxy-fuel combustion, and syngas gasification, were evaluated. The hydrogen required for methanol production comes from water electrolysis driven by solar and wind energy. In addition, the effect of location was discussed.

  • 207.
    Fivel, Johannes Bedoire
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Falk, Anders
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Framtidens avloppsvattenreningsverk – en modern energiproducent: En fallstudie av Himmerfjärdsverket2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In a sustainable society the use of renewable energy and recycling of materials is of high importance. Wastewater treatment plants use large amounts of energy in the processing of wastewater. This study seeks to evaluate wastewater as an energy resource and to examine treatment plants potential to become sustainable energy producers. The study is based upon the internal processes of Himmerfjärdsverket. Wastewater has a high content of heat energy because of its origin from households and industries. It also holds high concentrations of chemically bound energy as organic compounds and nutrients. The flow of chemically bound energy at Himmerfjärdsverket corresponds to a power of 15 MW. During the treatment processes sludge is separated from the wastewater. The sludge can be used for biogas production by anaerobic digestion. At Himmerfjärdsverket, 8 million m3 of biogas are produced every year. The reminder from the biogas production can be used as fertilizer in the farming industry. 56 % of the biogas is sold as fuel and the remaining gas is used for internal processes. Himmerfjärdsverket could reduce its energy need for heating by half by installing a heat pump system. This would lead to annual savings of two million SEK. The conclusion is that modern wastewater treatment plants have the potential to become an important part of the next generation’s renewable energy system. 

  • 208.
    Fjæstad, Maja
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Filosofi och teknikhistoria, Teknik- och vetenskapshistoria.
    Teknikval är avgörande för kärnkraftens framtid2010Annet (Annet (populærvitenskap, debatt, mm))
  • 209.
    Forero, Carlos
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys. Ecole des Mines de Nantes, France.
    Small/medium scale hydropower implementation in developing countries: A Rwandan case study2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Small scale hydropower is one of the most cost-effective energy technologies to be considered for electrification in developing countries. The technology is very robust and mature so systems can last up to 50 years with little maintenance. Moreover, it has low environmental impacts and can have a significant benefit if implemented in rural areas for electricity production, either in on or off grid applications.The thesis reviews several small scale hydropower projects, in order to identify potential risks and propose guidelines to help future implementation of this technology in a better way than the one currently done. An on-going project was taken as a case study to identify different elements that have to be present in the planning and future development of small scale hydro projects in developing countries. Technical, managerial, socio-economical and environmental aspects around the project were analyzed within a sustainability framework.

  • 210.
    Fransson, Jimmy
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Sahlsten, Minna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Life Cycle Cost: Studie om LCC som verktyg att utvärdera geoenergianläggningar2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Life Cycle Cost, often abbreviated as LCC, is a common tool for comparing the total cost of different alternatives, such as heating and cooling methods. Common heating and cooling methods in Sweden are geothermal energy, district heating and district cooling. This report aims to evaluate how different heating and cooling methods differ from each other while being applied on three different types of buildings, using selected LCC-models. Information about the selected LCC-models wasretrieved from each separate model and its website. Reports and agencies were used as sources for information about the heating and cooling methods. Tendersby established energy companies in Sweden were used as input data to form different alternatives for each building. From the comparison between the selected LCC-models, both similarities and differences were identified. The differences vary both in scale and how they affect the result. Nonetheless two of the models show the same results for some of the alternatives. In order to approximate the environmental effects for each heating and cooling method, carbon dioxide emissions were compared. The conclusion of this report is that while there are significant differences between the different LCC-models, the results only differ marginally for most models. 

  • 211. Franzese, Pier Paolo
    et al.
    Lazarevic, David
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Reddy, Sudhakara
    Energy and Urban Systems2016Inngår i: Journal of Environmental Accounting and Management, ISSN 2325-6192, E-ISSN 2325-6206, Vol. 4, nr 2, s. 99-101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Energy and environmental security are major problems facing our global economy. Fossil fuels, particularly crude oil, are confined to a few regions of the world while the continuity of supply is governed by dynamic political, economic, and ecological factors. Cities and urban systems are largely dependent on local and imported resources in support of both quantitative and qualitative growth. However, modern cities are experiencing shortages of energy, water, clean air, social relations and cohesion, social inclusion, and ultimately lack of participatory governance of city complexity. At present about 50% of the world population (i.e., about 3.5 billion people) live in cities. The resource basis seems to be insufficient and unfairly distributed to support an acceptable standard of living for a large fraction of urban and rural population. In addition, the concentration of resources required to support cities places a huge load on surrounding environment. For these reasons, cities must face the challenge of reorganizing their infrastructures and lifestyles to cope with the decreasing availability of resources. The priority in policy making is to identify suitable policies to reorganize urban life in the presence of a shrinking resource basis. Such reorganization will have to make cities less energy and material demanding, although still providing high quality standards of life. This cannot occur without investments, research, and important and shared choices about lifestyles.

  • 212.
    Fröjd, Anna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Energi- och miljövinster med ett bygglogistikcenter i Norra Djurgårdsstaden: Förslag på metod för utvärdering2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I Norra Djurgårdsstaden i Stockholm pågår ett stort stadsutvecklingsprojekt där det planerats för ungefär 12 000 nya bostäder, 35 000 arbetsplatser och 600 000 kvadratmeter kommersiell yta. För att koordinera alla transporter av byggmaterial in till området, samt hantera avfallstransporter ut ur området, har Stockholms stad etablerat ett bygglogistikcenter vars mål bland annat är att reducera antalet transporter.

    Syftet med detta examensarbete har varit att ta fram en metod för utvärdering av potentiella miljöeffekter med bygglogistikcentret i Norra Djurgårdsstaden. Examensarbetet har tittat på byggtransportlogistik ur ett livscykelperspektiv för jämförelse mellan två olika scenarion, då ett bygglogistikcenter finns (scenario 1) respektive då ett sådant inte finns (scenario 2). De parametrar som ingått är partiklar och energianvändning samt CO2, NOx och SO2.

    Två olika beräkningsverktyg har jämförts och valet föll på ett verktyg från NTM, Nätverket för Transporter och Miljön. En genomgång av vilken information som erfordras för att göra beräkningar har gjorts och för att undersöka tillgången till dessa data har ett antal intervjuer samt en workshop genomförts med olika aktörer, både inom Norra Djurgårdsstaden men också utifrån. Andra saker som diskuterades var aktörernas syn på bygglogistikcentret, vad som kan förbättras med det samt hur själva utfallet av en utvärdering skulle kunna förbättras, exempelvis genom styrning i upphandlingsprocessen. Intervjuer och workshop har också varit viktiga i syfte att förankra den föreslagna utvärderingsmetoden hos aktörerna själva.

    Under intervjuer och workshop har det bland annat framkommit en del konstateranden och några förslag till förbättringar. Exempelvis sades att logistikfrågor lyfts upp enbart genom att bygglogistikcentret finns och att den största förbättringen med bygglogistikcentret anses vara att framkomligheten är mycket bättre än vad den annars hade varit. En annan sak som de flesta var eniga om var att krav i upphandling bör ställas så tidigt som möjligt för att de ska kunna få så stor effekt som möjligt.

    För att göra en utvärdering krävs data om alla olika transporter och för varje transporttyp behövs information inom tre olika kategorier: fordonet, lasten samt själva körvägen. Eftersom alla data inte finns tillgängliga idag kommer en del antaganden att behöva göras, hur många beror på när i tiden utvärderingen ska göras och hur noggrann den ska vara. Om en utvärdering ska göras snarast rekommenderas att ett antal manuella mätningar genomförs men för att utvärderingar ska kunna göras kontinuerligt föreslås att en del åtgärder vidtas för att automatisera insamlingen av data.

    Det rekommenderas också att en känslighetsanalys av erhållna mätvärden görs för bedömning av vilka data som är i störst behov av ökad noggrannhet för att utvärderingens tillförlitlighet ska öka. Beroende på vad en sådan analys visar ges förslag på några olika åtgärder som kan vidtas, såsom att montera kameror vid grindpassager för information om passerande fordon eller att installera datorer i vissa fordon för att få information om körbeteende. 

  • 213.
    Fu, Jenny
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Hammarsten, Hanna
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    An Analysis of Climate Change and its Effects on the Electricity Generation: Supporting a CLEWs assessment in Ghana2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Sustainable, effective and affordable access to energy plays a significant role when it comes to improving people's living conditions, and supporting human and economic development. Therefore, the access and availability of electricity is an important factor and indicator of how well developed a country is. Furthermore, the generation of electricity is often strongly interlinked with other sectors such as climate, land use, and water. All these resources’ systems can have a certain effect on the energy production and vice versa. It is therefore a complex sector, and it needs to be developed with these interlinkages in mind.

    The aim of this project is to study and analyze the future electricity system in Ghana and its linkages to climate change and water resources. In this project, the modelling tools focus to optimize the electricity generation in consideration of economic values, as well as analyzing climate change and its impact on electricity generation by hydropower.

    To make a projection of the electricity system in Ghana, two modelling tools were used in the study, OSeMOSYS and ONSSET. The results generated by the models give an indication of potential optimal generation mixes between 2015 and 2050, for the different set of considerations on which the scenarios were built. The projected electricity generation consists of a combination of both renewable energy technologies and fossil fuel dependent technologies. The contribution from concentrated solar power (CSP) stands for the largest share of the mix in the long term. The results also suggest that climate change most certainly will have an impact on the electricity production in Ghana, due to its effect on the performance of hydropower production. This is an indication that Ghana’s reliance on hydropower for its electricity production, could not be sustainable and reliable in the long term.

    Ghana is an unequally developed country and there are still many undeveloped regions with poor access to electricity, especially in the northern parts of the country. There is also a rising demand of water and land for agricultural use. Since these resources also are important for the sustainable production of electricity, further and more detailed investigation of the conflicts between these sectors is necessary for a sound and compatible sectoral development and sustainable management of resources.

  • 214.
    Fuso Nerini, Francesco
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energi och klimatstudier, ECS.
    POSSIBILITIES OF RURAL ELECTRIFICATION IN THE BRAZILIAN AMAZON: A Multi Criteria Analysis To Compare The Most Promising Technological Solutions2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    More than 20% of the world population still does not have access to electricity, approximately 1.411 billion people (IEA, 2011). Brazil represents a facet of this reality: electricity access has been recognized as a citizen right, and thanks to the program Luz Para Todos (Light for all) approximately 14 million people have received electricity access since 2003 in the country (ANEEL, 2010).

    However, further extension of the interconnected grid is no longer an option in the Amazon region, due to the long distances that need to be covered and a very difficult topography. There is a need for a new delivery model in which the demand-­‐‑side is privileged and decentralized solutions based on local renewable resources are well investigated. (Gómez and Silveira, 2012). More than 700.000 households still have to be served in Brazil with an off-­‐‑grid connection, most of those in the north of the country (ANEEL 2011). In addition,

    most of the local grids are unsustainably fuelled with Diesel fuel. Diesel generators (DG) are cheaper than renewable solutions in the short term but their operation is costly: The cost of diesel for isolated communities, once the transportation costs are considered, may be two or three times higher than prices charged at gas stations (Silva et al., 2010).

    This study explores the possibility of integrating renewable energy in the Amazon region, both for new installations and for hybridization of the existing diesel generators. For doing that a multi criteria analysis have been developed, to explore all the main aspects that should influence aware decisions among the various systems that can provide Energy services to rural populations in the Amazon. Economic, technologic, environmental, social and institutional factors are explored.

    With this methodology for each system compared the main positive and negative aspects for providing energy services to rural communities with a determined system are studied and commented. DG solutions, considered as benchmark, are compared with hybrid diesel systems (DG + PV), and with renewable systems chosen for their potential in the area (PV, Micro Hydro Installations and Biomass systems).

    The methodology and the conclusions are especially targeted to help decision makers in the region to make more informed choices, with the possibility of looking at a variety of different parameters during the decision process. 

  • 215.
    Fuso Nerini, Francesco
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys.
    Shore up support for climate action using SDGs correspondence2018Inngår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 557, nr 7703Artikkel i tidsskrift (Fagfellevurdert)
  • 216.
    Fuso Nerini, Francesco
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys. University College London, United Kingdom.
    Keppo, I.
    Strachan, N.
    Myopic decision making in energy system decarbonisation pathways. A UK case study2017Inngår i: Energy Strategy Reviews, ISSN 2211-467X, E-ISSN 2211-4688, Vol. 17, s. 19-26Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With an application on the UK, this paper shows that myopic planning might result in delayed strategic investments and in considerably higher costs for achieving decarbonisation targets compared to estimates done with perfect foresight optimisation energy models. It also suggests that carbon prices obtained from perfect foresight energy models might be under-estimated. The study was performed using a combination of the standard UK Times Model (UKTM), a perfect foresight, bottom-up, technology-rich cost optimisation energy model, and its myopic foresight version: My-UKTM. This also demonstrates that using perfect foresight optimisation models in tandem with their myopic equivalents can provide valuable indications for policy design.

  • 217.
    Fuso-Nerini, Francesco
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys.
    Dargaville, Roger
    Howells, Mark
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys. Columbia Univ, NY USA.
    Bazilian, Morgan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energisystemanalys.
    Estimating the cost of energy access: The case of the village of Suro Craic in Timor Leste2015Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 79, s. 385-397Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Energy access targets at national, sub-national, and local levels, are often not specified in great detail - and tend to focus on supply. Another approach to better inform policy and investment might benefit from an indicator that focuses on the services derived from electricity access. To provide support for decision-making, this research investigates the costs of reaching different levels of energy access in rural areas, with a case study of a village in the Ainaro district of Timor Leste. Utilizing the multi-tier definition of energy access proposed in the World Bank's "Global Tracking Framework" for Sustainable Energy for All, we present results both on the cost difference of achieving different tiers of energy access, and on the comparison among selected electrification and cooking options. Results show that in the period 2010-2030 achieving the highest tier of electricity access could be as much as seventy-five times more costly than achieving the lowest one. In addition moving across tiers, least cost solutions shift from stand-alone to mini-grid and finally grid connected options as electricity access increases. Regarding cooking, moving from open fires to some of the more modern solutions has the potential to reduce overall costs over the same period.

  • 218.
    Färegård, Simon
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Miletic, Marko
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    von Schultz, Erik
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Prospects of Renewable Energy for the New City of El Alamein, Egypt: An Energy System Model using OSeMOSYS to obtain the most cost-efficient electricity production mix2019Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    With the motivation to mitigate the effects caused by one of humankind’s biggest challenges, climate change, the purpose of this minor field study was to examine the prospects of renewable energy technologies as part of a larger ambition to offer clean and affordable energy for all, in line with United Nations Sustainable Development Goals. The study was conducted for El Alamein in Egypt, a city under construction that will house four million residents. By combining a field study and an interview with literature search, the information needed for an energy system model was gathered. The modelling system OSeMOSYS was thereafter used to calculate the most cost-efficient electricity mix for the model period of 2020 to 2040, based on different scenarios and technologies. The total discounted cost and amount of emissions were thereafter compared between the scenarios, and the most cost-efficient scenario at reducing emissions was identified.

    Of the scenarios that were compared to the reference case, the one where 50 % of the electricity was produced from renewables in 2040 proved to be the most cost-efficient option. In addition, this scenario was also the most cost efficient at reducing emissions by a large margin. Regarding the renewable technologies, solar photovoltaics, which represented a majority of the renewable electricity production, was evidently the most cost-efficient technology as well as the one with the highest potential for future implementation, followed by onshore wind power. Moreover, concentrating solar power and waste to energy were proven to have a lower potential. The conclusions drawn were that the city of El Alamein could get a substantial part of its electricity from renewables and that solar PV was the best technology for that purpose. The final conclusion was that there might exist great potential for renewable energy in Egypt.

  • 219.
    Gallego-Marcos, Ignacio
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnenergiteknik.
    Kudinov, Pavel
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnenergiteknik.
    Villanueva, Walter
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnkraftssäkerhet.
    Kapulla, R.
    Paranjape, S.
    Paladino, D.
    Laine, J.
    Puustinen, M.
    Räsänen, A.
    Pyy, L.
    Kotro, E.
    Pool stratification and mixing during a steam injection through spargers: analysis of the PPOOLEX and PANDA experiments2018Inngår i: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 337, s. 300-316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Spargers are multi-hole injection pipes used in Boiling Water Reactors (BWR) and Advanced Pressurized (AP) reactors to condense steam in large water pools. A steam injection induces heat, momentum and mass sources that depend on the steam injection conditions and can result in thermal stratification or mixing of the pool. Thermal stratification reduces the steam condensation capacity of the pool, increases the pool surface temperature and thus the containment pressure. Development of models with predictive capabilities requires the understanding of basic phenomena that govern the behavior of the complex multi-scale system. The goals of this work are (i) to analyze and interpret the experiments on steam injection into a pool through spargers performed in the large-scale facilities of PPOOLEX and PANDA, and (ii) to discuss possible modelling approaches for the observed phenomena. A scaling approach was developed to address the most important physical phenomena and regimes relevant to prototypic plant conditions. The focus of the tests was on the low steam mass flux and oscillatory bubble condensation regimes, which are expected during a long-term steam injection transient, e.g. in the case of a Station Black Out (SBO). Exploratory tests were also done for chugging and stable jet conditions. The results showed a similar behavior in PPOOLEX and PANDA in terms of jet induced by steam condensation, pool stratification, and development of hot layer and erosion of the cold one. A correlation using the Richardson number is proposed to model the erosion rate of the cold layer as a function of the pool dimensions and steam injection conditions.

  • 220.
    Gan, Philipe Gunawan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Deutsches Zentrum für Luft- und Raumfahrt (DLR), Linder Höhe, Cologne, 51147, Germany.
    Monnerie, N.
    Brendelberger, S.
    Roeb, M.
    Guédez, Rafael
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Sattler, C.
    Modeling, simulation and economic analysis of CSP-driven solar fuel plant for diesel and gasoline production2019Inngår i: AIP Conference Proceedings, American Institute of Physics (AIP), 2019, artikkel-id 180009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The present research focuses on modeling of solar thermal driven fuel production plant with CO2 and H2O as raw materials to produce synthetic gas (syngas) which is converted into hydrocarbons through Fischer-Tropsch process either with Fe and Co catalyst to produce diesel, gasoline and kerosene. The solar reactor uses cerium oxide (CeO2) as a metal-redox and operates at 1773 K and 1300 K for reduction and oxidation step respectively under non-stoichiometric condition. The plant is analyzed by performing a quasi-steady state simulation under boundary condition that the Fischer-Tropsch reactor should operate with the capacity factor of 0.95 or 8350 hours annually. A storage tank is used to store and regulate the flow of syngas going into the Fischer-Tropsch reactor. Sensitivity analysis is carried out, particularly on solar reactor conversion and solid-to-solid heat exchanger efficiency. Another sensitivity analysis is to combine PV and CSP as the external electricity source. The production cost is finally calculated using annuity method with constant discount rate.

  • 221.
    Ganesan, Aravind
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Development of a modern catalytic system for the production of C3+ aliphatic alcohols by the Fischer-Tropsch method2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis deals with converting a mixture of H2 and CO, also referred to as syngas or producer gas, to higher or mixed alcohols and other fuels through a process called Fischer Tropsch Synthesis (FTS). It is a beneficial pathway that minimizes the dependence on oil and similar fossil fuels which contribute to rapid climate change by releasing harmful greenhouse gases. The syngas used in FTS, is generally obtained through gasification of biomass to make the entire process renewable and to make the resulting fuel carbon neutral. The products are pure due to prior cleaning of syngas mixture to remove oxides of nitrogen, sulphur and other particulate matter, before the process, thereby drastically reducing the net exhaust gas emissions. The major objective of this project is to design a novel catalyst system and subject it to a series of experimentation for testing its selectivity towards alcohols. This is because the present catalytic systems are either very expensive to assemble or confer to a low yield. Two cobalt (Co) based catalysts, one without a promoter and the other which is promoted by zirconium (Zr), are prepared. The activity and selectivity of Co catalysts are finally compared with the existing Swedish Biofuels AB’s Iron (Fe) based catalyst promoted by copper (Cu) and chromium (Cr) along with characterization of the optimum reaction parameters like temperature, pressure, GHSV and syngas ratio for FTS. Aqueous incipient impregnation approach was adopted wherein the Co active metal and Zr promoter (only in second catalyst) are introduced step-wise on a ϒ-alumina support to synthesize the catalyst after which it is heat treated through drying, calcination and reduction to obtain the active Co metal catalyst. A high temperature FTS, was employed for the yield of alcohols and other gasoline derivatives according to literature. Finally, the liquid and gaseous products are analyzed through GC or GC/MS analysis techniques.

    The unpromoted Co catalyst’s activity is regarded as a failure due to satisfactory results. There were a few problems associated with the catalyst alone like poor mechanical stability that could be attributed to the use of an incorrect binder. Other problems included methanation due to haphazard temperature variations and inefficient catalyst reduction. For the promoted Co catalyst, the yield of alcohols and hydrocarbons was significantly higher than the unpromoted Co catalyst. A temperature of 300 °C, a GHSV of 360 h-1 , a pressure of 10 bar and a H2:CO ratio of 1.3:1 were the optimal background conditions for FTS. Higher temperature caused methanation and reduced the chain growth probability factor, α, that resulted in the formation of lower hydrocarbons only. Any increase in gas ratio and GHSV, also increased the rate of methane formation and caused diffusion limitations. For a one-stage setup with the reversal of exhaust gases, the conversion rates of CO and H2 were quite promising. This success can be attributed to a higher calcination temperature that increased the degree of reduction of Co due to formation of promoter oxides thereby enabling CO hydrogenation and H2 insertion. It helped to reduce CO2 formation as well. Even for the Fe catalyst, a low temperature, a low GHSV and low syngas ratio were preferred. But unlike its Co counterpart, a higher pressure favored an increase in yield of alcohols and other long chain hydrocarbons. Fe’s ability to support WGS reaction disturbed the molar ratio of CO and also released more CO2 that could affect the rate of syngas conversion. But, on the whole, Fe catalyst was efficient than Co catalyst for alcohol synthesis. The overall yield of alcohols was just 5% of the liquid products. Nearly 86% of the alcohol fraction comprised of C1, C2 and C3 alcohols alone and very few C4, C5 and C6 alcohols were obtained.

  • 222.
    Garcia, Jose Daniel
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Installations- och energisystem.
    Characterization of greywater heat exchangers and the potential of implementation for energy savings2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Buildings account for up to 32% of the total energy use in different countries. Directives from the European Union have pointed out the importance of increasing energy efficiency in buildings. New regulation in countries like Sweden establishes that new buildings should fulfill regulations of Nearly Zero Energy Buildings (NZEB), opening an opportunity for new technologies to achieve these goals. Almost 80-90% of the energy in domestic hot water use is wasted from different applications with almost no use and with a lot of potential energy to be recovered.

    The present work studied the characteristics of greywater heat exchanger as a solution to recuperate heat from greywater to increase efficiency in buildings. This study explored the fluid mechanics involved in the vertical greywater heat exchangers, analyzing the falling film effect present in drain pipes and the effects of the secondary flow generated in the external helical coil. A heat transfer model from a theoretical approach was proposed and validated. In addition, this study explored the different variables influencing the economic feasibility of the technology and an economic analysis was performed. A theoretical comparison between a greywater heat exchanger application and a reference case without it was evaluated highlighting the importance of all the variables involved in the potential of implementation of the technology. The technology shows big potential in households with high water consumptions, especially with electric boilers.

  • 223.
    Garrido, Jorge
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Aichmayer, Lukas
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Abou-Taouk, Abdallah
    Azelio, Regnbagsgatan 6, S-41755 Gothenburg, Sweden..
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Experimental and numerical performance analyses of Dish-Stirling cavity receivers: Radiative property study and design2019Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 169, s. 478-488Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The solar receiver performance has a direct impact on the CSP power plant performance and, thereby, its levelized cost of electricity. Improved receiver designs supported by new advanced numerical tools and experimental validation campaigns directly help to make CSP technology more competitive. This paper presents an experimental and numerical investigation of the influence of the cavity receiver radiative properties and the thermal power input on the Dish-Stirling performance. Three cavity coatings are experimentally investigated: the original cavity material (Fiberfrax 140), Pyromark 2500 and Pyro-paint 634-ZO. Moreover, simulations validated with the experimental measurements are utilized to define a higher performance cavity receiver for the Eurodish system. The results indicate that the absorptivity of the cavity should be as low as possible to increase the receiver efficiency whereas the optimum emissivity depends on the operating temperatures. If the cavity temperature is lower than the absorber temperature, low emissivities are recommended and vice-versa. All material/coatings analyzed for the cavity provide similar receiver efficiencies, being Fiberfrax 140 slightly more efficient. Finally, a total receiver efficiency of 91.5% is reached by the proposed Eurodish cavity receiver when operating under the most favorable external conditions. 

  • 224.
    Garrido, Jorge
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Sjöqvist, R.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Mechanical coupling behavior of a dish-Stirling receiver: Influence on the absorber tube stresses2019Inngår i: AIP Conference Proceedings, American Institute of Physics (AIP), 2019, Vol. 2126, artikkel-id 050003Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The solar receiver tubes work under the highest temperatures and heat flux conditions, being their thermo-mechanical design critical to assure a safe and durable operation. Finite Element Analyses are traditionally utilized to assess the stresses for lifetime calculations. However, the real boundary conditions for these analyses are not well known yet. Thereby, this paper presents an experimental and numerical study to determine more realistic boundary conditions. Firstly, four deflection measurements are measured simultaneously by high-accuracy laser meters. Secondly, three types of boundary conditions are simulated trying to fit the experimental deflections: fixed, elastic and remote displacement. Finally, the stresses at critical regions are compared for each simulation. The results show that, unlike fixed support, remote displacement boundary conditions can obtain realistic deflection results but must be re-adjusted for each specific support, and elastic support fails to capture the manifold rotations. Using remote displacement stress results as reference for the case under study, fixed support leads to deviations in the stresses of at least 50% whilst elastic support can provide some similar stress results.

  • 225. Geng, Y.
    et al.
    Wei, Y. -M
    Fischedick, M.
    Chiu, A.
    Chen, B.
    Yan, Jinyue
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser. Malardalen University (MDU), Sweden.
    Recent trend of industrial emissions in developing countries2016Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 166, s. 187-190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Greenhouse gas (GHG) emissions from industrial sectors are increasing, particularly in the developing world where pursuing industrialization has been highly addressed. This calls for further studies to learn and share experiences for developing countries. In order to fill in such a research gap, this special issue focuses on examining the recent trend of industrial emissions in developing countries. Among the manuscripts submitted to the Special Issue, twelve papers have been accepted after review, covering assessment indicators, tools and methods, and policies. Key industrial sectors, including cement, lime, aluminum, coal, mining, glass, soda ash, etc, have been investigated. Valuable policy insights have been raised, including wide scale upgrading, replacement and deployment of best available technologies, integrated information platforms, cross-cutting technologies and measures, a shift to low carbon electricity, radical product innovations, carbon dioxide capture and storage (CCS), demand on new and replacement products, systematic approaches and collaboration among different industries. These useful suggestions could be shared or learned by industrial policy makers or managers in the developing world so that the overall GHG emissions from their industrial sectors can be mitigated by considering the local realities.

  • 226.
    Gezork, Tobias
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Völker, S.
    Applicability of quasi-3d blade design methods to profile shape optimization of turbine blades2013Inngår i: Proc. ASME Turbo Expo, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The performance of gas turbine airfoils is continually improved by creating advanced aerodynamic and thermal designs. Optimization methods are used to handle the increasing complexity of such a design. However, optimization is expensive when performed based on 3D CFD calculations. Therefore, an optimization strategy based on simpler, less expensive analysis methods is desirable. Oftentimes, a so-called quasi-3D (Q3D) approach is used, where 2D calculations are carried out on multiple, radially stacked meridional blade sections. This paper investigates the applicability of such an approach for optimization with regard to blade profile loss. Obviously, certain physical effects are neglected using this approach, leading to errors in the predicted blade performance. Still, optimization based on Q3D calculations might be possible if the error is consistent, i.e. not random. For this purpose, a design of experiment (DOE) was carried out to compare and correlate loss predictions from Q3D calculations and high-fidelity 3D CFD calculations for gas turbine blades. It is shown that the total pressure loss coefficients found with both the Q3D and 3D calculations correlate well (75-90%) to warrant the use of a Q3D method for profile shape optimization. Subsequently, an optimization is performed to demonstrate the applicability of the method.

  • 227.
    Ghaem Sigarchian, Sara
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Malmquist, Anders
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    The choice of operating strategy for a complex polygeneration system: A case study for a residential building in Italy2018Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 163, s. 278-291Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The operating strategy can affect the optimal solution and performance of a polygeneration energy system. In this study, the effect of operating strategies: following thermal load; following electric load; and modified base load on the optimal solution of a polygeneration system for a residential building complex in the northern part of Italy is investigated. For the optimal solutions, a comparative analysis is carried out considering the techno-economic and environmental performance of the system. The result elaborates on how the benefits achieved in a polygeneration system are influenced by the choice of operating strategy. In the building complex, implementation of the operating strategies shows considerable energetic, economic and environmental benefits compared to conventional separate heat and power generation. The ranges of annualized total cost reduction of 17-19%, carbon dioxide emission reduction of 35-43% and fuel consumption reduction of 30-38% are achieved for the various operating strategies. However, each of the operating strategies has its own advantages and drawbacks which emphasizes the importance of post-processing of the results in order to make the right choice. For example, the following thermal load shows the advantage of a higher carbon dioxide emission reduction. On the other hand, one drawback is its lower self-sustainability in terms of electric power compared to the other strategies.

  • 228. Gharakhanlou, J.
    et al.
    Kazachkov, Ivan V.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Konoval, O. V.
    Development and investigation of the mathematical models for potentially hazardous nuclear power objects with deviated arguments2013Inngår i: WSEAS Transactions on Applied and Theoretical Mechanics, ISSN 1991-8747, E-ISSN 2224-3429, Vol. 8, nr 4, s. 241-257Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper is devoted to one of the problems of system analysis for nuclear power plants (NPP) in touch with the modelling and simulation of the potentially hazardous objects in nuclear power safety including severe accidents at the nuclear power plants. Development and implementation of the mathematical models for analysis and computer simulations of the passive protection systems against severe accidents and mathematical modelling and simulation of the potentially hazardous objects (PHO) with account of different deviating arguments concerning the real features are considered. It has concern to a need of the planning and decision making in the environmental and other tasks.

  • 229. Ghasemi, S.
    et al.
    Costa, G.
    Zingaretti, D.
    Bäbler, Matthäus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Baciocchi, R.
    Comparative Life-cycle Assessment of Slurry and Wet Accelerated Carbonation of BOF Slag2017Inngår i: 13th International Conference on Greenhouse Gas Control Technologies, GHGT-13, 14-18 November 2016, Lausanne, Switzerland, Elsevier, 2017, Vol. 114, s. 5393-5403Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work reports the results of the life cycle assessment (LCA) of two carbonation processes aimed at permanent CO2 storage, employing Basic Oxygen Furnace (BOF) slag from steel manufacturing as alkalinity source. Specifically, the performance of the slurry phase and wet carbonation routes were compared assuming to store the CO2 emitted from a 10 MW conventional natural gas power plant. The LCA was based on the material and energy requirements for each of the involved process steps, i.e. pre-treatment and transport of raw materials, CO2 compression, carbonation, post treatments and management of the obtained products. The slurry and wet route resulted in a net avoided greenhouse warming potential (GWP) of 473 and 384 kg CO2/MWhel, respectively. Nevertheless, both routes affected the other environmental impact categories. In general, the wet route had approximately two times higher impact than the slurry route, due in particular to the higher material and energy requirements. An exception was the abiotic resource depletion which resulted higher for the slurry route due to greater water requirement with respect to the wet route. The contributions to all mid-point impact categories were mainly due to energy requirements. A sensitivity analysis showed that the environmental impacts are affected by the energy mix and by the transport distance of slags and carbonation products.

  • 230.
    Ghasemi, Sara
    KTH, Skolan för kemivetenskap (CHE).
    Comparative Life-Cycle Assessment of Slurry vs. Wet Carbonationof BOF Slag2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Accelerated carbonation is a new C02 storage method under development as a  solutionfor climatechangecausedbyanthropogenicactivities.Inacceleratedcarbonationanalkalinesourcesuch as minerals or industrial resid ues react with carbon dioxide in a presence of slightly acidicsolution to produce stable solid carbonates. There are varieties of accelerated carbonation routes,which differ in process condition. The aim of this study was to evaluate  and  compare  the potential of a slurry route process and a wet route process for the carbonation of basicoxygenfurnace slag using the C02 emitted by a conventional natural gas power plant. For this pmpose alife cycle assessment (LCA) study was performed based on principles and guidelines provided byISO 14040:2006 and routines and data provided by the SimaPro V8 software  package.Thematerial and energy requirements for each of the steps involved in the carbonation process, i.e.pre-treatment of raw material, C02 compression, transportation, carbonation step, after-treatmentand landfill, were calculated and included in the LCA study. The slurry and wet route resulted innet C02 reduction of 87.4% and 72.3% respectively. However, a positive contribution to otherenvironmental issues was observed with the wet route  leading to higher  impact mainly due  tohigh heating requirement. An exception was the contribution of the slurry route  to  abioticresource depletion, which was higher for the slurry route due to high water  requirement.  Ageneral conclusion was that the electricity consumption is the  main  cause  ofenvironmentalissues. Sensitivity analyses showed that the environmental impacts are dependent on thetransp01iation distance and electricity source, while no dependence was observed with respect toconstruction of the carbonation plant.

  • 231.
    Giesecke, Oskar
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Karlsson, Rikard
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Vindkraftpark på Öland: En förstudie omelproduktion och lönsamhet2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    För att öppna dörren till mer vindkraft i Sverige, krävs förstudier för områdesspecifika vindkraftparker. Detta projekt har som syfte att beräkna vilken elproduktion som kan förväntas hos en fiktiv vindkraftspark placerad på mellersta Öland. Därutöver görs en ekonomisk analys, vilken ska uppskatta parkens ekonomiska intäkt för den förväntade produktionen. Intäkter fås främst ur försäljning av elenergi på den nordiska elbörsen samt certifikatmarknaden. Om vindkraftsparken består av 3 vindturbiner med märkeffekten 3.3 MW och medelvindhastigheten stämmer överens med mätdata, förväntas parken ge en årlig elproduktion av 29,6 GWh. I den ekonomiska analysen har två fall resulterat till en minimal och en maximal ekonomisk intäkt. Det lägsta fallet visas ge en total intäkt av 291 Mkr. Det högsta fallet beräknades till 398 Mkr. Dessutom har fasta investeringskostnader och räntekostnader beräknats till 230 Mkr. Detta betyder att Vindkraftparken kommer få en vinst mellan 218 Mkr och 111 Mkr, exklusive kostander från nätförluster, drift och underhåll. 

  • 232.
    Gimenez Gavarrell, Pau
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Guidelines of how to instrument, measure and evaluate refrigeration systems in supermarkets2011Independent thesis Advanced level (degree of Master (One Year)), 30 poäng / 45 hpOppgave
  • 233.
    Gołombek, Roger
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö. Silesian University of Technology.
    Experimental investigation of thermal conversion of solid waste under high temperature agent (steam/air)2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Most of the problems with providing a continuous and sustainable energy supply for the worldwide society are negative consequences to the environment and its living habitants steaming from uses of conventional technologies. Those consequences should be minimized by developing and improving new technologies as well as by utilization of other type of feedstock than fossil fuels, such as biomass, industrial or municipal solid waste. Nowadays, gasification is the main technology for biomass conversion to energy and a great alternative for the thermal treatment of solid waste. The number of various applications for produced gas shows the flexibility of gasification and that is why allows it to be integrated with other industrial processes, as well as power generation systems.

                The main objectives of this thesis were to present behavior of different kind of feedstock undergoing pyrolysis/gasification processes in reactors using highly preheated agents and additionally compare the compositions of produced gases. In this thesis two different systems were presented; the first is lab-scale gasifier for the treatment of biocoal, automotive shredder residue (ASR), refuse derived fuel (RDF), biomass (straw pellets) and plastic waste (polyethylene) and the second one is a large up-draft, fixed bed gasifier used for investigation of biocoal.

    The thesis was divided into four main parts: beginning with theoretical introduction, subsequently showing outcomes from investigations carried out on lab-scale test unit, large HTAG facility and finishing on short conclusions.

  • 234.
    Grahn, Pia
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Alvehag, Karin
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Söder, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Plug-in-vehicle mobility and charging flexibility Markov model based on driving behavior2012Inngår i: 9th International Conference on the European Energy Market, EEM 12, IEEE , 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Climate targets around the globe are enforcing new strategies for reducing climate impacts, which encourage automobile and electricity companies to consider an electrified vehicle market. Furthermore, the variable electricity production in the electric power system is increasing, with higher levels of wind and solar power. Due to the increased variability in the system, the need to meet fluctuations with flexible consumption is intensified. Electric vehicles with rechargeable batteries seem to become an increasingly common feature in the car fleet. Plugin vehicles (PIVs), may therefore become valuable as flexible consumers. If so, flexible PIV owners could, if they are flexible enough, increase the value of owning an electric vehicle. This paper introduces a new PIV Mobility and Charging Flexibility Markov Model, based on driving behavior for private cars. By using the new model, it is possible to simulate the potential flexibility in a future system with many PIVs. The results from a case study indicate a potential need for usage of the batteries as flexible loads to reduce the grid power fluctuations and load peaks.

  • 235.
    Granestrand, Jonas
    et al.
    KTH.
    Dahlin, Sandra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Processteknologi.
    Immele, O.
    Germany.
    Schmalhorst, L.
    Germany.
    Lantto, C.
    Nilsson, M.
    París, R. S.
    Regali, F.
    Pettersson, L. J.
    Catalytic aftertreatment systems for trucks fueled by biofuels - Aspects on the impact of fuel quality on catalyst deactivation2018Inngår i: Catalysis:: Volume 30, Royal Society of Chemistry, 2018, s. 64-145Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The issue of sustainable energy supply is a global problem for pursuing future endeavours in the energy area. In countries such as China and India there is a tremendous growth at the moment, which is envisaged by an ever growing demand for vehicles. Hence, one of the grand challenges of society is to meet the demands for sustainable and environmentally-friendly technologies in the transport sector. One way to tackle the problem of growing concentrations of carbon dioxide, which is believed to contribute to global warming, is the use of biofuels. It is becoming more and more evident that global warming is partly due to increasing anthropogenic carbon dioxide emissions. An important contribution to these emissions is the use of fossil fuels in the transport sector. Hence, more efficient engines and an increased use of biofuels would be a step in the right direction. Although new propulsion systems are emerging, such as hybrid power-trains and fuel cell systems, analysis shows that combustion systems with excess oxygen, such as the diesel engine, will be the most important engine concept for the next 20 years. In this paper we will identify the specific challenges related to the production and use of biofuels in heavy-duty trucks and how they influence the catalytic units in the emission after-treatment system in the truck. Biofuels, such as biodiesel, contain potential poisons for the vehicle exhaust after-treatment, such as potassium, sodium, magnesium, phosphorus, zinc, sulfur and other compounds.

  • 236.
    Granqvist, Jessica
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Gao, Lily
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    The electricity demand andsupply in El Espino: Alternatives for diversification of renewabletechnologies2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The use of alternative fuels, particularly renewable energy sources, has been an important strategy to achieve greenhouse gas emission reductions. In Bolivia, many rural areas struggle with an unreliable power supply. The most common electricity solution in such isolated areas is to have off-grid systems, where hybrid systems have become a feasible solution. In this study, a hybrid system in the rural village El Espino is optimized using a linear programming tool called MicroGridsPy. Currently, the village is powered by a hybrid system consisting of solar photovoltaics, a diesel generator and lead-acid batteries as a storing system. To optimize the system in a sustainable way, considering economic, environmental and social aspects, two wind turbines of the nominal capacities 5 and 10 kW are studied and introduced to the hybrid system. To find synergies between the wind and solar energy, the irradiance and wind speed of the study area are simulated using a Weather Research and Forecasting (WRF) model. The power output from the wind turbines can then be obtained by modelling the power curves and then be added to the optimization model. The optimization is performed both with and without the wind turbines to evaluate the impact of them. In the optimization model, characteristics of the components, techno-economic parameters, including investment costs, and constraints such as renewable penetration, and cost of the curtailment are set.

    The obtained results include that the wind speed is higher during the winter season, and that the wind power output, regardless of turbine size, is proportional to the wind speed. Furthermore, the 10 kW wind turbine is proven to be the most suitable for the system of the two compared. The economical values of the system, such as NPC and LCOE are higher, the higher the renewable penetration, but lower for the system with wind turbines. This implicates that adding wind energy to the hybrid system could be beneficial from both an environmental and economical point of view. One conclusion that can be drawn is that wind turbines are a feasible technology for rural electrification, and that the optimization tool is sensitive to cost. Furthermore, it is found that the wind and solar energy are suitable complements to each other both season wise and daily.

  • 237.
    Gravoille, Pauline
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    CASE STUDY OF ACTIVE FREE COOLING WITH THERMAL ENERGY STORAGE TECHNOLOGY2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    May 25, 2011, Reuters’ headline read: "New York State is prepared for summerelectricity demand". The NY operator forecasts for next summer a peak of 33GW, close to therecord ever reached. With soaring cooling demands, the electricity peak load represents a substantialconcern to the energy system. In the goal of peak shaving, research on alternative solutions based onThermal Energy Storage (TES), for both cooling and heating applications, has been largely performed.This thesis addresses thermal comfort applications with use of active free cooling through implementationof latent heat based TES. Active free cooling is based on the use of the freshness of a source, the outsideair for example, to cool down buildings. This work conceptualizes the implementation of TES basedcooling system with use of Phase Change Material in an in-house-built model. The principle of PhaseChange Material, or Latent Heat TES (LHTES), lies on latent energy which is the energy required for thematerial to change phase. In order to properly size this cooling system, a multi-objective optimization isadopted. This optimization, based on minimization of multi-objective functions, led to optimal designconfigurations. In parallel, the electrical consumption of the system and the volume uptake of the systemwere also considered. Through the obtained optimization studies, we identified non-linearinterdependency between the two objective functions: the cost of the system and the acceptable remainingcooling needs. By remaining cooling needs, we mean the cooling needs that the system cannot meet. As amatter of fact, sizing the system according to these cooling needs would imply a very high cost. It wasfound that for a certain amount of remaining cooling needs, the PCM-based cooling system reveals to bean interesting solution compared to conventional air conditioning in terms of electrical consumption andoverall system cost.

  • 238.
    Grigoryeva, Anna
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Hesamzadeh, Mohammad Reza
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Tangerås, T.
    Energy system transition in the Nordic market: Challenges for transmission regulation and governance2018Inngår i: Economics of Energy & Environmental Policy, ISSN 2160-5882, E-ISSN 2160-5890, Vol. 7, nr 1, s. 127-146Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The energy system in the Nordic countries faces changes driven by increasing integration with the rest of Europe and changes to the generation mix. These developments pose challenges with respect to future network development and operation. We focus on three major aspects: market integration; generation and network adequacy; the need for more flexibility and frequency control. We describe factors behind these problems and present possible solutions within the Nordic context. One conclusion is that supranational cooperation should be further improved.

  • 239.
    Guan, Tingting
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Biomass-fuelled PEM FuelCell systems for small andmedium-sized enterprises2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biomass-fuelled proton exchange membrane fuel cells (PEMFCs) offer asolution for replacing fossil fuel for hydrogen production. Through using thebiomass-derived hydrogen as fuel, PEMFCs may become an efficient andsustainable energy system for small and medium-sized enterprises. The aim ofthis thesis is to evaluate the performance and potential applications of biomassfuelledPEMFC systems which are designed to convert biomass to electricity andheat. Biomass-fuelled PEMFC systems are simulated by Aspen plus based ondata collected from experiments and literature.The impact of the quality of the hydrogen-rich gas, anode stoichiometry, CH4content in the biogas and CH4 conversion rate on the performance of the PEMFCis investigated. Also, pinch technology is used to optimize the heat exchangernetwork to improve the power generation and thermal efficiency.For liquid and solid biomass, anaerobic digestion (AD) and gasification (GF),respectively, are relatively viable and developed conversion technologies. ForAD-PEMFC, a steam reformer is also needed to convert biogas to hydrogen-richgas. For 100 kWe generation, the GF-PEMFC system yields a good technicalperformance with 20 % electrical efficiency and 57 % thermal efficiency,whereas the AD-PEMFC system only has 9 % electrical efficiency and 13 %thermal efficiency. This low efficiency is due to the low efficiency of theanaerobic digester (AD) and the high internal heat consumption of the AD andthe steam reformer (SR). For the environmental aspects, the GF-PEMFC systemhas a high CO2 emissions offset factor and the AD-PEMFC system has anefficient land-use.The applications of the biomass-fuelled PEMFC systems are investigated on adairy farm and an olive oil plant. For the dairy farm, manure is used as feedstockto generate biogas through anaerobic digestion. A PEMFC qualified for 40 %electrical efficiency may generate 360 MWh electricity and 680 MWh heat peryear to make a dairy farm with 300 milked cows self-sufficient in a sustainableway. A PEMFC-CHP system designed for an olive oil plant generating annual 50000 m3 solid olive mill waste (SOMW) and 9 000 m3 olive mill waste water(OMW) is simulated based on experimental data from the Biogas2PEM-FCproject1. After the optimization of the heat exchanger network, the PEMFC-CHP 

    system can generate 194 kW electricity which corresponds to 62 % of the totalelectricity demand of the olive oil plant.The economic performance of the PEMFC and biogas-fuelled PEMFC areassessed roughly including capital, operation & maintenance (O&M) costs of thebiogas plant and the PEMFC-CHP, the cost of heat and electricity, and the valueof the digestate as fertilizer.

  • 240.
    Guan, Tingting
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Chutichai, Bhawasut
    Alvfors, Per
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Energiprocesser.
    Arpornwichanop, Amornchai
    Biomass-fuelled PEMFC systems: Evaluation of two conversion pathsrelevant for different raw materials2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 106, s. 1183-1191Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biomass-fuelled polymer electrolyte membrane fuel cells (PEMFCs) offer a solution for replacing fossilfuel with hydrogen production. This paper uses simulation methods for investigating biomass-fuelledPEMFCs for different raw materials and conversion paths. For liquid and solid biomass, anaerobic diges-tion (AD) and gasification (GF), respectively, are relatively viable and developed conversion technologies.Therefore, the AD-PEMFC system and the GF-PEMFC system are simulated for residential applications inorder to evaluate the performance of the biomass-fuelled PEMFC systems. The results of the evaluationshow that renewable hydrogen-rich gas from manure or forest residues is usable for the PEMFCs andmakes the fuel cell stack work in a stable manner. For 100 kWe generation, the GF-PEMFC system yieldsan excellent technical performance with a 20% electric efficiency and 57% thermal efficiency, whereas theAD-PEMFC system only has an 9% electric efficiency and 13% thermal efficiency due to the low efficiencyof the anaerobic digester (AD) and the high internal heat consumption of the AD and the steam reformer(SR). Additionally, in this study, the environmental performances of the AD-PEMFC and the GF-PEMFC interms of CO2emission offset and land-use efficiency are discussed.

  • 241.
    Guerin, Vincent
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Optimization of the operation and monitoring of large-scale photovoltaic power plant2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The monitoring and supervision of large scale solar photovoltaic plants becomes more and more important nowadays, with the increase of the installed power. The detection system and the reactivity must be improved in order to allow the plants to run at their best capacity. One way to improve that detection is the setup of alerts triggering for certain types of defaults concerning the performance of the inverters or the plant itself. That setup can be optimized by analytical analysis on the historic data of the plant, and adjusted for each plant, depending on its behavior. Another way is to calculate robust indicators such as the performance ratio, which corresponds to the efficiency of the plant, regardless the type of installed panels. This indicator depends on the electricity production and the received irradiance. In order to have an accurate measure of that indicator, a work on the reconstitution of the missing data must be done for the irradiance measure. That reconstitution enables to have access to a robust measure of the performance ratio and thus to improve the monitoring of the performances of the plant.

  • 242.
    Gunasekara, Saman Nimali
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Phase Equilibrium-aided Design of Phase Change Materials from Blends: For Thermal Energy Storage2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Climate change is no longer imminent but eminent. To combat climate change, effective, efficient and smart energy use is imperative. Thermal energy storage (TES) with phase change materials (PCMs) is one attractive choice to realize this. Besides suitable phase change temperatures and enthalpies, the PCMs should also be robust, non-toxic, environmental-friendly and cost-effective. Cost-effective PCMs can be realized in bulk blends. Blends however do not have robust phase change unless chosen articulately. This thesis links bulk blends and robust, cost-effective PCMs via the systematic design of blends as PCMs involving phase equilibrium evaluations. The key fundamental phase equilibrium knowledge vital to accurately select robust PCMs within blends is established here. A congruent melting composition is the most PCM-ideal among blends. Eutectics are nearly ideal if supercooling is absent. Any incongruent melting composition, including peritectics, are unsuitable as PCMs. A comprehensive state-of-the-art evaluation of the phase equilibrium-based PCM design exposed the underinvestigated categories: congruent melting compositions, metal alloys, polyols and fats.

    Here the methods and conditions essential for a comprehensive and transparent phase equilibrium assessment for designing PCMs in blends are specified. The phase diagrams of the systems erythritol-xylitol and dodecane-tridecane with PCM potential are comprehensively evaluated. The erythritol-xylitol system contains a eutectic in a partially isomorphous system unlike in a non-isomorphous system as previous literature proposed. The dodecane-tridecane system forms a probable congruent minimum-melting solid solution, but not a maximum-melting liquidus or a eutectic as was previously proposed. The sustainability aspects of a PCM-based TES system are also investigated. Erythritol becomes cost-effective if produced using glycerol from bio-diesel production. Olive oil is cost-effective and has potential PCM compositions for cold storage. A critical need exists in the standardization of methods and transparent results reporting of the phase equilibrium investigations in the PCM-context. This can be achieved e.g. through international TES collaboration platforms.

  • 243.
    Gunasekara, Saman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Chiu, Justin NingWei
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Phase equilibrium in the design of phase change materials for thermal energy storage: State-of-the-art2017Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 73, s. 558-581Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    This paper presents a review of phase equilibrium as a tool for accurately identifying suitable blended phasechange materials (PCMs) to be used for thermal energy storage (TES). PCM storage increases the overall energyefficiency for many applications, however, high cost and complex phase change phenomena in blends oftenundermine the benefits. The study of phase equilibrium as derived from phase diagrams is the key to solve theseissues. It enables the evaluation of PCM-suitability through indication of temperature-composition points, e.g.congruent melting compositions, eutectics and peritectics. To clearly stake out the opportunities of a phaseequilibrium-based design methodology, this paper reviews the state-of-the-art based on findings from fourdecades (1977–2016). On one hand, eutectics, salts-based systems, fatty acids, and alkanes dominate theexisting PCM literature. Here peritectics have often been erroneously praised as suitable PCMs despite the manyproblems depicted from a phase equilibrium point of view. On the other hand, the most PCM-ideal congruentmelting systems, as well as the blends of polyols, fats, metal alloys and organic-inorganic combinations lack fullattention. This work brings forward the knowledge on these insufficiently explored yet extremely suitable phaseequilibrium characteristics. In addition, comprehensive PCM-design thermal properties of these various blendsare presented, as a basis to further extensive explorations, and material category-based predictions.

  • 244.
    Gunasekara, Samman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Chiu, Justin NingWei
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Hedström, Peter
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    The Experimental Phase Diagram Study of the Binary Polyols System Erythritol-Xylitol2017Inngår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 174, s. 248-262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A comprehensive phase diagram for the binary polyols system erythritol-xylitol has been mapped with a transparent characterization approach. Here, the phase equilibrium of the system has been studied experimentally using a combination of methods: Temperature-history (T-history), X-Ray Diffraction (XRD), and Field-Emission Scanning Electron Microscopy (FESEM), and linked to Tammann plots. Existing literature has previously shown the system to be a non-isomorphous type forming a simple eutectic, by combining experimental data with theoretical modelling. The present investigation shows that the system’s phase diagram is a partially isomorphous type forming a eutectic, but not a non-isomorphous type forming a simple eutectic. Here, the eutectic was found within 25-30 mol% erythritol and at 77 °C, which differs from the previous studies identifying the eutectic respectively at 25 or 36 mol% erythritol and at 82 °C. The reasons for the differences are hard to deduce since the research approach is not presented as fully transparent from the past studies. In the present study, only the temperature-composition plot of the first melting (of the two components in a physical mix, but not of a single blend) indicated the shape of a simple eutectic in a non-isomorphous system. The cycles after the first melting in contrast started from the real blend, and displayed eutectic and solid-solid phase changes in T-history. These were verified as forming solid solutions with XRD and FESEM. This eutectic melts at a temperature suitable for low-temperature solar heating, but displayed glass transition, supercooling, and thermally activated degradation, thus affecting its practical aspects as a PCM.

  • 245.
    Gunasekara, Samman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Ignatowicz, Monika
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Chiu, Justin NingWei
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Thermal Conductivity Measurement of Erythritol, Xylitol and Their Blends for Phase Change Materials Design: a Methodological Study2018Inngår i: The 14th International Conference on Energy Storage, Adana, Turkey: IEA ECES , 2018, s. 364-378, artikkel-id 82Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work presents and discusses a detailed thermal conductivity assessment of erythritol, xylitol and their blends: 25 mol% erythritol and 80 mol% erythritol using the Transient Plane Source (TPS) method with a Hot Disk Thermal Constants Analyzer TPS-2500S. Their thermal conductivities were here found to be respectively: 0.59; 0.37; 0.39 and 0.54 W/(m·K) in the solid state, and to be 0.32; 0.43; 0.40 and 0.36 W/(m·K) in the liquid state. These obtained results are comprehensively and critically analyzed as compared to available literature data on the same materials, in the phase change materials (PCMs) design context. This study clearly indicates that the literature has considerable discrepancies among their presented thermal conductivities, and also as compared to the values found through the present investigation. Primary reason for these disparities are identified here as the lack of sufficiently transparent and repeatable data and procedure reporting, and relevant standards in this context. To exemplify the significance of such transparent and repeatable data reporting in thermal conductivity evaluations in the PCM design context, here focused on the TPS method, a comprehensive measurement validation is discussed along various residual plots obtained for varying input parameters (i.e., the heating power and time). Clearly, the variations in the input parameters give rise to various thermal conductivity results, where choosing the most coherent result requires a sequence of efforts per material, but there are no universally valid conditions. Transparent and repeatable data and procedure reporting is the key to achieve comparable thermal conductivity results, which are essential for the correct design of thermal energy storage systems using PCMs.

  • 246.
    Gunasekara, Samman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Laios, Michail
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Karabanova, Anastasiia
    Technical University of Denmark - DTU.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Blanchard, Didier
    Technical University of Denmark - DTU.
    Design of a bench-scale ammonia-SrCl2 thermochemical storage system using numerical modelling2019Inngår i: Eurotherm Seminar #112 - Advances in Thermal Energy Storage, Lleida, 2019, artikkel-id D128Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This work presents the numerical modelling of a bench-scale thermochemical storage (TCS) system based on the reversible absorption-desorption of ammonia in strontium chloride. The modelling is performed using the ASPEN software and was validated against experimental data from literature on a different TCS system configuration but using the same reaction pair. The modelled TCS system in this work comprises two identical reactors, alternatively operating as absorber or desorber with a storage capacity of 0.5 kWh. The system is designed to store and release heat under 8 bar of NH3 pressure, with the two identical reactors respectively undergoing desorption at 82 °C and absorption at 79 °C. Together with the two reactors, a liquid ammonia storage tank is used as a buffer (10 bar at 25 oC). The desorption half-cycle of the system is made of the desorber (82 °C, 8 bar), a compressor (8-10 bar), a cooler (108-25 °C), a pump (to pump liquid ammonia) and the liquid ammonia storage (25 °C, 10 bar). The absorption half-cycle starts form the liquid ammonia storage tank and goes via an expansion valve (10-8 bar) and then a heater (18-25 °C) towards the absorber (79 °C, 8 bar). In the model, the desorption and absorption are respectively driven by an external heater and cooler, which represent a waste heat source and a heat sink respectively. The efficiency of the TCS system was found to be of 67 % and 61 % for the absorption and desorption half-cycles, respectively. A sensitivity analysis was also conducted to identify optimum operating conditions. In conclusion, this study presents an ammonia-SrCl2 TCS bench-scale system that allows simultaneous heat storage and retrieval, as the basis for the practical construction of the system. This is expected to provide inspiration and operational analysis to accommodate the design of similar TCS systems for storing surplus industrial heat.

  • 247.
    Gunasekara, Samman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Mao, Huahai
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Bigdeli, Sedigheh
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Chiu, Justin NingWei
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Thermodynamic Assessment of Binary Erythritol-Xylitol Phase Diagram for Phase Change Materials DesignManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Here, the experimental phase equilibrium data of the erythritol-xylitol system were thermodynamically optimized, to explore compositions suitable as phase change materials (PCMs) for thermal energy storage (TES). A previous experimental study revealed that erythritol-xylitol was a partially isomorphous system with a eutectic. In the thermodynamic evaluation, the CALPHAD method was employed coupling the phase diagram and thermodynamic property information. There, both unary and binary systems’ experimental data were taken into account, and all phases were described using the substitutional solution model. Finally, a self-consistent thermodynamic description for the erythritol-xylitol system was achieved. The calculated eutectic point is at 76.7 °C and 26.8 mol% erythritol, agreeing well with the experimental data. The calculated phase diagram better-verifies the systems’ solidus and the solvus, disclosing the stable phase relations. Based on the Gibbs energy minimization, phase diagrams can be predicted for the binary and higher order systems, provided the component subsystems are thermodynamically assessed beforehand. In conclusion, to move forward beyond e.g. non-isomorphous simple eutectic systems, methods using Gibbs free energy minimization from a fundamental point-of-view such as CALPHAD are essential.

  • 248.
    Gunasekara, Samman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Edén, Ted
    Norrenergi AB, Solna, Sweden.
    Sedeqi, Faisal
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Tavares, Miguel
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Mayo Nardone, Pablo Sabino
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Distributed cold storages for district cooling in Sweden- The current context and opportunities for the cold supply expansion2019Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This work analyzes the current context of district cooling (DC) in Sweden and thereby proposes opportunities in cost-effective and environmentally friendly expansion of cold supplies. The current state of DHC in Sweden here is mapped via a comprehensive literature assessment coupled with information collection from individual DHC suppliers in Sweden. These findings are concisely discussed herein, mapping the current context of DC in Sweden. The investigation here yields that the cold supply in Sweden today is achieved by employing free cooling (FC, extracting cold from natural cold sources, e.g. deep sea, river or lake water, via heat exchangers), absorption coolers (ACs), compression coolers (CCs) as well as heat pumps (HPs, with or without heat recovery), and cold storages (mainly using water). This technology mix is used in varying shares by different regions, based on the available resources, e.g. large water bodies to drive FC. When excess heat is available, AC is also a preferred choice. HPs are becoming increasingly interesting, for their synergies in simultaneously providing heat and cold. The peak demands of cold are met with cold storages as well as more ‘operationally’ expensive technologies, such as CCs. The cold storages primarily cover the daily cold peaks in summer, driven by the large differences in the cooling loads between the day and night. The current DC provision in Sweden is around 1 TWh, while the total cooling demand is around 3-5 TWh, therefore with a clear deficit in supply. Interestingly, the DC supply is projected to grow up to around 3 TWh by 2030. With population growth, the DC demands will also rise, and fulfilling these cooling demands with cost-effective and renewable solutions is imperative. To inspire the Swedish DC growth, herein certain international examples on power-to-cold (PtC) combining peak shaving with cold storages, e.g. based on water, ice, and thermochemical heat storage systems (TCS) are also discussed. Finally, critical reflections are given, identifying opportunities to improve the current context of DC in Sweden with cost-effective and environmental-friendly solutions.

  • 249.
    Gunasekara, Samman Nimali
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Stalin, Joseph
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Marçal, Mariana
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Delubac, Regis
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. University of Pau and Pays de l'Adour, France.
    Karabanova, Anastasiya
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Gubkin Russian State University of Oil and Gas, Russia.
    Chiu, Justin NingWei
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Martin, Viktoria
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Erythritol, Glycerol, their Blends, and Olive Oil, as Sustainable Phase Change Materials2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 135, s. 249-262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In searching for new candidates to be used in latent heat storage, it is desirable to explore food-grade materials of renewable origin. Here, erythritol, glycerol, and olive oil have been characterized as PCMs. An assessment of the production process of erythritol (melting between 117-120 °C with an enthalpy around 300 kJ/kg) indicates its renewable aspects as a PCM. In addition, a simplified cost assessment of high-purity erythritol production, using glycerol, indicates a potential cost reductions up to 130-1820 times lower than the current laboratory-grade prices. Glycerol already is cost-effective. However, the glycerol-erythritol system, evaluated using the Temperature-history (T-history) method, did not exhibit phase change suitable for PCMs. Glycerol, and up to 30 mol% erythritol compositions had no phase change due to glass transition; the remainder froze but with large supercooling; and the system underwent thermally activated change. Hence, to realize glycerol or the glycerol-erythritol system as PCMs, further research is needed primarily to device fast-crystallization. Olive oil is a cost-effective food commodity, with potential for further cost reductions by mass-production. An olive oil sample, containing the fatty acids: linoleic, palmitic, oleic, margaric, and stearic was evaluated using the T-history method. This olive oil melted and froze between -4.5 to 10.4 °C and -8 to -11.9 °C respectively, with the respective enthalpies 105 and 97 kJ/kg. As the specific heat (cp) profiles of olive oil displayed two peaks, the composition adjustment of olive oil could yield a eutectic or confirm a polymorph. In either case, olive oil has a potential to be a PCM e.g. in chilling applications, while its properties such as thermal conductivity need to be determined. As a whole, this study exemplifies the potential of renewable organic materials, in pure and blend forms, as sustainable PCMs, making TES with PCMs sustainable.

  • 250.
    Gustafsson, Marcus
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Strömnings- och klimatteknik. Dalarna University, Sweden.
    Swing Gustafsson, Moa
    Högskolan Dalarna, Energiteknik; Mälardalens Högskola.
    Myhren, Jonn Are
    Högskolan Dalarna, Byggteknik.
    Bales, Chris
    Högskolan Dalarna, Energiteknik.
    Holmberg, Sture
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Strömnings- och klimatteknik.
    Techno-economic analysis of energy renovation measures for a district heated multi-family house2016Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 177, s. 108-116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Renovation of existing buildings is important in the work towards increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO₂ emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.

    Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO₂ emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact.

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