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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Projekt ORC cyklu / Project ORC -cycle

Černý, Jakub January 2014 (has links)
The aim of this thesis is the project for biomass cogeneration units using ORC cycle and subsequent use of thermal energy for drying wood biomass for a briquetting line. The introducing sections describe the principle of cogeneration, organic Rankine cycle (primarily the indication of potential applications and their use in practice) and the selection of the proper working fluid. The following sections provide a technical description of the selected plants for cogeneration unit, total circulation scheme and calculation of the evaporator working fluid. The last section is devoted to the economic evaluation of three variants according to the investor's task to design a better option for implementation.
2

Radial turbine expander design, modelling and testing for automotive organic Rankine cycle waste heat recovery

Alshammari, Fuhaid January 2018 (has links)
Since the late 19th century, the average temperature on Earth has risen by approximately 1.1 °C because of the increased carbon dioxide (CO2) and other man-made emissions to the atmosphere. The transportation sector is responsible for approximately 33% of the global CO2 emissions and 14% of the overall greenhouse gas emissions. Therefore, increasingly stringent regulations in the European Union require CO2 emissions to be lower than 95 gCO₂/km by 2020. In this regard, improvements in internal combustion engines (ICEs)must be achieved in terms of fuel consumption and CO2 emissions. Given that only up to 35% of fuel energy is converted into mechanical power, the wasted energy can be reused through waste heat recovery (WHR) technologies. Consequently, organic Rankine cycle (ORC) has received significant attention as a WHR technology because of its ability to recover wasted heat in low- to medium-heat sources. The Expansion machine is the key component in ORC systems, and its performance has a direct and significant impact on overall cycle efficiency. However, the thermal efficiencies of ORC systems are typically low due to low working temperatures. Moreover, supersonic conditions at the high pressure ratios are usually encountered in the expander due to the thermal properties of the working fluids selected which are different to water. Therefore, this thesis aims to design an efficient radial-inflow turbine to avoid further efficiency reductions in the overall system. To fulfil this aim, a novel design and optimisation methodology was developed. A design of experiments technique was incorporated in the methodology toexplorethe effects of input parameters on turbine performance and overall size. Importantly, performance prediction modelling by means of 1D mean-line modelling was employed in the proposed methodology to examine the performance of ORC turbines at constant geometries. The proposed methodology was validated by three methods: computational fluid dynamics analysis, experimental work available in the literature, and experimental work in the current project. Owing to the lack of actual experimental works in ORC-ICE applications, a test rig was built around a heavy-duty diesel engine at Brunel University London and tested at partial load conditions due to the requirement for a realistic off-high representation of the performance of the system rather than its best (design) point, while taking into account the limitation of the engine dynamometer employed. Results of the design methodology developed for this projectpresented an efficient single-stage high-pressure ratio radial-inflow turbine with a total to static efficiency of 74.4% and an output power of 13.6 kW.Experimental results showed that the ORC system had a thermal efficiency of 4.3%, and the brake-specific fuel consumption of the engine was reduced by 3%. The novel meanlineoff designcode (MOC) was validated with the experimental works from three turbines. In comparison with the experimental results conducted at Brunel University London, the predicted and measured results were in good agreement with a maximum deviation of 2.8%.
3

Utveckling av dataanalysprogram för Opcon Powerbox / Development of data analysis software for Opcon Powerbox

Holmgren, Magnus January 2010 (has links)
Opcon Powerbox is a product developed by Opcon together with the underlying company SRM (Svenska Rotor Maskiner) where surplus heat from the industry is used through an Organic Rankine Cycle (ORC)–process to produce electricity. An ORC-process is a thermodynamic circle process in which a refrigerant is used as the working fluid. The refrigerant makes it possible for the circle process to operate at lower temperatures than the conventional Rankine process. In this master’s thesis a data analysis software for the Opcon Powerbox has been developed in which measurement data is retrieved and handled from the Opcon Powerbox. The software performs calculations and analysis on the data with which the system can be evaluated. This thesis has been carried out with SRM.
4

Elproduktion med ORC-teknik ombord på fartygsserien MK II.

Lundgren, Per, Mohlin, Håkan January 2012 (has links)
Given that the oil prices have risen and the environmental regulations has become more stringent, the interest in operating efficiency has increased. The project has investigated the possibility of producing electricity from waste heat generated in the diesel process. One technique to utilize and convert energy into electricity is the ORC (Organic Rankine Cycle). This process is based on the Rankine process (the steam process), the difference from the traditional Rankine process is that instead of water as a working medium, an organic substance is used. The main component used in the process is a evaporator, a turbine, a condenser and a pump. Opcon is a company that markets a product based on the ORC technology, called the Powerbox. During autumn 2011 and spring 2012, a feasibility study commissioned by Stena RoRo to investigate whether the Powerbox is suitable for Stenas RoRo ship series Mk II for electricity generation, in terms of economic viability and proper placement on the basis of the necessary peripherals. The survey shows that the Powerbox can be placed on the ship series Mk II. Stena has stated that this investment should have a pay-back time in three years. The Powerbox will be paid off after eight years. / Med anledning av att oljepriset har stigit och att miljökraven blivit strängare har intresset för driftoptimering ökat. Projektet har undersökt möjligheten att utvinna elektricitet från den spillvärme som uppkommer i dieselprocessen. En teknik som finns för att tillvarata och omvandla energin till elektricitet är ORC (ORGANIC RANKINE CYCLE). Denna process bygger på Rankines process (ångprocessen), skillnaden mot den traditionella Rankineprocessen är att istället för vatten som arbetsmedium används ett organiskt ämne. De huvudkomponenter som används i processen är förångare, turbin, kondensor och en pump. Opcon AB är ett företag som marknadsför en produkt som bygger på ORC-tekniken, en så kallad Powerbox. Under ht 2011 och vt 2012 har en förstudie gjorts på uppdrag av Stena RoRo för att undersöka om Opcons Powerbox är lämplig på Stenas fartygsserie Mk II för elproduktion, med avseende på ekonomisk lönsamhet samt lämplig placering utifrån nödvändig kringutrustning. Undersökningen visar att Powerboxen kan placeras på fartygsserien Mk II. Stena har uppgett att denna investering bör ha en avbetalningstid på tre år. Powerboxen kommer att vara avbetalad efter åtta år.
5

Adding MRP/DRP functionality to Microsoft Navision /

Lo, Tou. January 2008 (has links)
Thesis (M.S.E)--University of Wisconsin -- La Crosse, 2008. / Includes bibliographical references (p. 45).
6

Geothermisch angetriebene Dampfkraftprozesse

Köhler, Silke January 2006 (has links)
Zugl.: Berlin, Techn. Univ., Diss, 2005
7

Organisk Rankine cykel i konfiguration med naturgasdrift.

Hektor, Eric January 2023 (has links)
Organisk Rankine cykel är en förångningscykel med användningen av en organisk fluid för att få bättre lågtempererade egenskaper än vid användningen av vattenånga. Naturgas är ett bränsle som används inom industrin och sjöfarten, den förvaras mycket kallt i vätskeform för att spara utrymme. Detta bränsle förångas antingen naturligt eller med syftet att förbränna den i gasform. Detta för att minska behovet av kryogenisk teknik. Förångningen sker med att tillföra värme till bränslet. Genom att förgrena ångcykelns behov av kondensering och bränslets behov av värme kommer massflödet för kondenskylningen att minska. Det ger i sin tur en stadigare drift i varma miljöer. Frågeställningen var hur mycket effekt som kunde hämtas ur denna konfiguration. Hur mycket mindre kondenseringsanläggningen blir och den möjliga systemkonfigurationen utifrån aspekten av säkerhet, effekt och goda möjligheter till reglering. Tillvägagången var först att studera systemen ingående, hur de funkar och för att ta fram de fysikaliska data. Sedan teoretiskt bygga samman systemen och göra beräkningar. Resultatet påvisade låg effekt men med ett behov av en 11 gånger mindre kondensor jämfört med vattenkylning. Slutsatsen är att denna konfiguration begränsar den potentiella effekten mycket men minskar effektbehovet för att driva ångprocessen och att kondenseringsanläggningen blir mindre. / Organic Rankine cycle is a vaporization cycle where an organic fluid is used toobtain better low-temperature properties than when using water vapor. Natural gasis a fuel used in industry and shipping it is stored very cold in liquid form to savespace. This fuel is either vaporized naturally or with the aim of burning it in gaseousform. This is to reduce the need for cryogenic technology. Vaporization takes placeby adding heat to the fuel. By branching the steam cycle's need for condensation andthe fuel's need for heat, the mass flow for condensation cooling will decrease. Thisin turn provides a more stable operation in warm environments. The question washow much power could be extracted from this configuration. How much smaller thecondensing plant will be and the possible system configuration from the aspect ofsafety, power, and good solutions for control. The approach was to first study thesystems in detail, how they work and to produce the physical data that was required.Then theoretically build the systems together and make calculations. The resultshowed low power but with a need for an 11 times smaller condenser compared towater cooling. The conclusion is that this configuration greatly limits the potentialpower but reduces the power requirement to drive the steam process and thecondensing plant becomes smaller.
8

Optimisation robuste de turbines pour les cycles organiques de Rankine (ORC) / Robust optimization of ORC turbine expanders

Bufi, Elio Antonio 14 December 2016 (has links)
Au cours des dernières années, le cycles organique de Rankine (ORC) ont reçu un grand intérêt de la communauté scientifique et technique en raison de sa capacité à récupérer de l'énergie à partir de sources de chaleur faible. Dans certaines applications, comme la récupération de chaleur des déchets (WHR), les plantes ORC doivent être aussi le plus compact possible en raison de contraintes géométriques et de poids. Récemment, ces questions ont été étudiées dans le but de promouvoir la technologie ORC pour moteur à combustion interne (ICE). L'idée de récupérer ce résidu d'énergie est pas nouvelle et dans les années 1970 la crise énergétique a encouragé le développement de petite ORC plants (1-10 kWe). En raison de la complexité moléculaire du fluides de travail , fort effets de gaz réel doivent être pris en compte en raison de la haute pression et la densité, si on le compare à un gaz idéal. Dans ces conditions, le fluide est connu comme gaz dense. Les gaz denses sont définis comme des vapeurs monophasés, caractérisé par des molécules complexes et avec importantes masses moléculaires. Le rôle de gaz dense dans la gaz dynamique des flux transsonique interne a été largement étudié pour son importance dans les turbomachines. Récemment, l'attention a été concentrée sur des turbines axiales, qui réduisent au minimum la taille du système, en comparaison avec les solutions radiales dans les mêmes rapports de pression et la chute d'enthalpie. Dans ce travail, une nouvelle méthodologie de conception de turbines ORC supersonique est proposé. Elle consiste dans un design à deux dimensions rapide et précise qui est réalisée pour stator et rotor avec une metode de caractéristique (MOC) étendue à une équation d'etat générique. Les effets visqueux sont pris en compte par l'introduction d'une correction turbulente appropriée de la couche limite compressible. Étant donné que les sources de chaleur proposées pour turbines ORC comprennent typiquement des sources d'énergie variables, comme la WHR des procédés industriels ou des applications automobiles, pour améliorer la faisabilité de cette technique, la résistance à des conditions variables d'entrée est prise en compte. L'optimisation numérique sous incertitudes est appelé Optimisation robuste (RO) et il surmonte la limitation de l'optimisation déterministe qui néglige l'effet des incertitudes dans les variables de design et / ou des paramètres de design. Pour mesurer la robustesse d'un nouveau design, les statistiques (la moyenne et la variance, ou écart-type) d'une réponse sont calculées dans le processus RO. Dans ce travail, la conception MOC des ORC aubes supersoniques est utilisé pour créer une profil de référence. Cela est optimisé grâce à une boucle RO. L'optimiseur stochastique est basée sur un modèle de krigeage bayésien de la réponse du système aux paramètres incertains, utilisé pour l'approximation des statistiques de la sortie du système, couplé à une algorithme genetique multi-objectif (NSGA). Une forme optimale qui maximise la moyenne et minimise la variance de l'efficacité isentropique est recherché. L'efficacité isentropique est évaluée au moyen de simulations RANS (Reynolds Average Navier-Stokes) de l'aube. Le comportement thermodynamique du fluide de travail est modélisée au moyen de l'équation d'etat de Peng-Robinson-stryjek-Vera. La forme de l'aube est paramétrée au moyen d'une approche Free Form Deformation. Pour accélérer le RO processus, une modèle de krigeage supplémentaire est construit pour la fonction multi-objectifs et une stratégie adaptif de remplissage basée sur le Multi Objective Expected Improvement es prise en compte afin d'améliorer la précision de krigeage à chaque génération de la NSGA. La forme robuste optimisé d'aube ORC est comparé aux résultats fournis par le MOC et l'optimiseur déterministe. / In recent years, the Organic Rankine Cycle (ORC) technology has received great interest from the scientific and technical community because of its capability to recover energy from low-grade heat sources. In some applications, as the Waste Heat Recovery (WHR), ORC plants need to be as compact as possible because of geometrical and weight constraints. Recently, these issues have been studied in order to promote the ORC technology for Internal Combustion Engine (ICE) applications. The idea to recover this residual energy is not new and the 1970s energy crisis encouraged the development of feasible ORC small-scale plants (1-10 kWe). Due to the molecular complexity of the working fluids, strong real gas effects have to be taken into account because of the high pressures and densities, if compared to an ideal gas. In these conditions the fluid is known as dense gas. Dense gases are defined as single phase vapors, characterized by complex molecules and moderate to large molecular weights. The role of dense gas dynamics in transonic internal flows has been widely studied for its importance in turbomachinery applications involved in low-grade energy exploitation, such as the ORC. Recently, the attention has been focused on axial turbines, which minimize the system size, if compared with radial solutions at the same pressure ratios and enthalpy drops. In this work, a novel design methodology for supersonic ORC axial impulse turbine stages is proposed. It consists in a fast, accurate two-dimensional design which is carried out for the mean-line stator and rotor blade rows of a turbine stage by means of a method of characteristic (MOC) extended to a generic equation of state. The viscous effects are taken into account by introducing a proper turbulent compressible boundary layer correction to the inviscid design obtained with MOC. Since proposed heat sources for ORC turbines typically include variable energy sources such as WHR from industrial processes or automotive applications, as a result, to improve the feasibility of this technology, the resistance to variable input conditions is taken into account. The numerical optimization under uncertainties is called Robust Optimization (RO) and it overcomes the limitation of deterministic optimization that neglects the effect of uncertainties in design variables and/or design parameters. To measure the robustness of a new design, statistics such as mean and variance (or standard deviation) of a response are calculated in the RO process. In this work, the MOC design of supersonic ORC nozzle blade vanes is used to create a baseline injector shape. Subsequently, this is optimized through a RO loop. The stochastic optimizer is based on a Bayesian Kriging model of the system response to the uncertain parameters, used to approximate statistics of the uncertain system output, coupled to a multi-objective non-dominated sorting genetic algorithm (NSGA). An optimal shape that maximizes the mean and minimizes the variance of the expander isentropic efficiency is searched. The isentropic efficiency is evaluated by means of RANS (Reynolds Average Navier-Stokes) simulations of the injector. The fluid thermodynamic behavior is modelled by means of the well-known Peng-Robinson-Stryjek-Vera equation of state. The blade shape is parametrized by means of a Free Form Deformation approach. In order to speed-up the RO process, an additional Kriging model is built to approximate the multi-objective fitness function and an adaptive infill strategy based on the Multi Objective Expected Improvement for the individuals is proposed in order to improve the surrogate accuracy at each generation of the NSGA. The robustly optimized ORC expander shape is compared to the results provided by the MOC baseline shape and the injector designed by means of a standard deterministic optimizer.
9

"AMANTE DE SELVAGEM REBELIÃO": A FIGURAÇÃO SATÂNICA NAS PROFECIAS CONTINENTAIS DE WILLIAM BLAKE / "LOVER OF WILD REBELLION": THE SATANIC FIGURATION IN WILLIAM BLAKE'S CONTINENTAL PROPHECIES

Santos, Andrio de Jesus Rosa dos 16 December 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this study, I analyze the thematic development of William Blake s satanic figure, the character Orc. To this end, I approach the illuminated poems called ―Continental Prophecies‖, which are composed by the books America A Prophecy (1793), Europe A Prophecy (1794) and The Song of Los (1795), that is divided into two parts, ―Africa‖ and ―Asia‖. In these works, Blake articulates themes such as apocalypse, energy, imagination and revolution in a relation to the French and the American Revolution and criticizes the political, religious and artistic thinking of the period. Of the matter of methodology, this work presents four chapters. In the first, I discuss the problems about the Devil s theme, from the Middle Ages to the Romanticism, starting by a mythical-religious approach of this figure, and then investigating the demon as a literary myth. In the second, I present a discussion about the characterization of Orc and his opponent, Urizen. I also analyze the poem America, focused on questions about desire, revolution and liberty. In he third, I discuss about Europe and proceed with the mapping of the satanic theme in Blake s prophecies. I also approach the question of the repression of desire, represented by the character Enitharmon, and discuss the subversions undertaken by Blake on religious dogma. In the fourth, I approach The Song of Los and argue about the blakean mythology, his ideal of Satanism, and also confront critical reading and interpretive perspectives of Blake s work. My discussion is developed in a constant dialogue between three instances: religious, social and artistic. This conception was thought by Peter Schock (2003), treated as a ―Cultural Matrix‖. This study explores how Blake s art dialogues with eighteenth century revolutions, it discuss its religious, political and artistic influences, and offers a conception of Blake s satanic ideal in his prophecies. The character Orc, in these poems, presents an amalgam of his artistic, religious and social thinking, an instance of confrontation through which Blake conceive metaphysical ideals, as the philosophy of contraries or the sensual enjoyment. Through the development of the Devil s theme, the artist tries to signify conflicting thoughts as sin and sensual delight, heaven and hell, body and soul, subverting these issues by a infernal ideal. / Neste estudo, analiso o desenvolvimento temático da figura satânica na obra de William Blake, a personagem Orc. Para tal, trabalho com os poemas iluminados denominados de ―Continental Prophecies‖, compostos pelas obras America A Prophecy (1793), Europe A Prophecy (1794) e The Song of Los (1795), este dividido em duas partes, ―Africa‖ e ―Asia‖. Nessas obras, Blake articula temas como apocalipse, energia, imaginação e revolução em relação à Revolução Francesa e à Americana e tece críticas ao pensamento político, religioso e artístico do período. Este trabalho apresenta quatro capítulos. No primeiro, discuto os problemas acerca do tema do Diabo, desde o medievo até o Romantismo, partindo de uma abordagem mítico-religiosa para então abordar o demônio como mito literário. No segundo, apresento uma discussão sobre a caracterização da personagem Orc e sua relação com seu opositor, Urizen. Construo também uma análise do poema America, centrada em questões sobre desejo, revolução e liberdade. No terceiro, trato de Europe e prossigo com o mapeamento da temática satânica nas profecias de Blake. Abordo também a questão da repressão do desejo, representada pela personagem Enitharmon, e as subversões empreendidas por Blake acerca de dogmas religiosos. No quarto, abordo The Song of Los e discorro sobre a mitologia blakeana, seu ideal de satanismo, além de confrontar vieses críticos de leitura e interpretação da obra de Blake. Minha discussão é desenvolvida em um constante diálogo entre três instâncias: religiosa, social e artística. Tal concepção é abordada por Peter Schock (2003), tratada como ―Matriz Cultural‖. Este estudo explora como a arte de Blake dialoga com as revoluções do século XVIII, discute suas influências religiosas, políticas e artísticas, além de oferecer uma concepção acerca do ideal satânico de Blake em suas profecias. A personagem Orc, nesses poemas, apresenta um amálgama do pensamento artístico, religioso e social do artista, uma instância de confronto através da qual Blake concebeu ideais metafísicos, como a filosofia dos contrários ou o deleite dos sentidos. Através do desenvolvimento do tema do diabo, o artista tenta significar pensamentos conflitantes, como pecado e deleite sensual, céu e inferno, corpo e alma, subvertendo tais questões a partir de um ideal infernal.
10

Comparative studies and analyses of working fluids for Organic Rankine Cycles - ORC

Nouman, Jamal January 2012 (has links)
No description available.

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