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Fasquelle, Thomas. "Modélisation et caractérisation expérimentale d’une boucle solaire cylindro-parabolique intégrant un stockage de type thermocline". Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0040/document.
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Comme les autres technologies liées aux énergies renouvelables, le solaire à concentration souffre des problèmes liés à l’intermittence de la ressource. La technologie thermocline est une solution prometteuse qui réduirait le coût du stockage thermique dans les centrales solaires de ce type. Cependant, aucune étude n’a jusqu’ici porté sur l’impact de la variation de la température en sortie du réservoir de stockage de type thermocline sur les autres composants de la centrale. Ce travail de thèse a pour but d’améliorer les connaissances sur ce sujet, grâce à l’utilisation d’une mini boucle solaire cylindro parabolique intégrant un stockage thermocline.En premier lieu, la compatibilité entre le fluide de transfert de la centrale (huile synthétique) et les potentiels matériaux de garnissage de la cuve de stockage (Cofalit, briques de cendres volantes, alumine) est vérifiée. Puis les performances de chacun des composants de la centrale (cuve de stockage, collecteurs solaires, générateur de vapeur) sont analysées expérimentalement et numériquement. Enfin, le comportement du système global est étudié, avec un accent porté sur l’impact de la variation de la température de sortie de la cuve thermocline sur les autres composants.Il a été montré qu’avec un dimensionnement et une stratégie de contrôle appropriés, la technologie thermocline diminue très peu les performances de la centrale solaire par rapport à la technologie conventionnelle à deux cuves (maximum 3 4 % de diminution de la production électrique)Like other renewable energy technologies, concentrated solar power (CSP) suffers from resource intermittence. Thermocline technology is a promising solution to decrease cost of thermal energy storage in CSP plants. Thermocline behavior has thoroughly been studied in the past years and its behavior is considered well known. However no study treated of thermocline tanks integrated in CSP plants. Thus, the impact of the varying outlet temperature of the thermocline storage has not been assessed yet. This work aims to fill this lack of knowledge by studying a mini parabolic trough power plant integrating a thermocline tank as storage.First, the compatibility between the heat transfer fluid of the plant (synthetic oil) and various potential filler materials (Cofalit, coal fly ash bricks, alumina) of the storage tank is verified. Then, some performance studies are performed on the three main components of the power plant (energy storage tank, solar collectors, steam generator). Finally, the behavior of the whole system is assessed, with a focus on the impact of the varying fluid temperature at the outlet of the thermocline tank on the other components.It has been shown that, with a proper sizing and an appropriate control strategy, thermocline technology induces very low decrease of the solar power plant performance in comparison to the conventional two tank technology (maximum 3-4% of electrical power production difference)
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Koninck, Corentin. "Procédés solaires basse température pour la désinfection d'eau de surface". Electronic Thesis or Diss., Perpignan, 2024. https://theses.hal.science/tel-04867589.
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Les difficultés d'accès à l'eau potable, affectent le quotidien de 2 milliards de personnes et constituent une problématique majeure à résoudre. Le sixième objectif de développement durable, mis en place par les Nations Unies, a pour but de promouvoir l'accès universel à l'eau potable en développant les possibilités d'assainissement et de potabilisation de l'eau dans les milieux urbains mais également au niveau des sites isolés. Ces derniers sont caractérisés par l'absence de réseaux énergétiques, la rareté de personnels techniques qualifiés et la difficulté d'acheminer des matières premières. Le développement de procédés décentralisés, durables, autonomes énergétiquement, répond au besoin de traitement de l'eau contre la pollution microbiologique, cause de nombreux décès à travers le monde. Deux procédés, avec le solaire thermique basse température comme source d'énergie, et basés respectivement sur le principe de la pasteurisation et de l'ultrafiltration membranaire de l'eau, sont conçus, expérimentés et modélisés. L'objectif est de démontrer la possibilité d'assurer la désinfection d'eau de surface à l'échelle des petites communautés décentralisées à partir d'une énergie délivrée par des collecteurs thermiques plans standards. Le procédé solaire de pasteurisation développé, permet de traiter, en fonction des conditions d'irradiation, des volumes journaliers compris entre 800 et 1000 L par unité de capteur (2 m2 de surface). La consommation d'énergie solaire spécifique, optimisée grâce à l'utilisation d'un échangeur de chaleur performant positionné sur la boucle ouverte de traitement, varie entre 12 et 15 kWhsol.m-3. Il fonctionne de manière totalement autonome au fil du soleil avec un système de régulation passif. Le procédé d'ultrafiltration repose sur deux innovations : (i) la production de l'énergie mécanique nécessaire au fonctionnement du système membranaire par un cycle thermodynamique de type organique Rankine dont l'entrée de chaleur est fournie par un collecteur solaire ; (ii) l'utilisation de l'énergie mécanique pour le pompage et la pressurisation de l'eau par actionnement d'un vérin double effet. La faisabilité technique du procédé est vérifiée avec une consommation énergétique spécifique fluctuant entre 5 et 10 kWhsol.m-3. Dans les deux cas, une modélisation est réalisée et validée à partir des résultats expérimentaux. Le couplage des deux technologies, permet d'envisager, d'une part la génération du perméat constituant une eau propre à la consommation, et d'autre part de la désinfection du concentrât qui est traitée par la suite par le procédé de pasteurisation. Ce système de désinfection associe performance énergétique et zéro rejetDifficulties in accessing drinking water affect the daily lives of 2 billion people, and represent a major problem to be solved. The 6th Sustainable Development Goal, set by the United Nations, aims to promote universal access to drinking water by developing sanitation and potabilization facilities in urban areas, and in isolated sites. The latter are characterized by the absence of energy networks, the scarcity of qualified technical personnel and the difficulty of transporting raw materials. The development of decentralized, sustainable, energy-independent processes meets the need to treat water against microbiological pollution, the cause of many deaths worldwide. Two processes, using low-temperature solar thermal energy as an energy source, and based respectively on the principle of water pasteurization and membrane ultrafiltration, are being designed, tested and modelled. The aim of this project is to demonstrate the feasibility of disinfecting surface water on the scale of small decentralized communities, using energy supplied by standard flat-plate thermal collectors. Depending on irradiation conditions, the solar pasteurization process developed can treat daily volumes of between 800 and 1000 L per collector unit (2 m2 surface area). Specific solar energy consumption, optimized through the use of a high-performance heat exchanger positioned on the open treatment loop, varies between 12 and 15 kWhsol.m-3. It operates completely autonomously with the sun, using a passive control system. The ultrafiltration process is based on two innovations: (i) the production of the mechanical energy required to operate the membrane system by an organic Rankine thermodynamic cycle whose heat input is supplied by a solar collector; (ii) the use of mechanical energy to pump and pressurize the water by actuating a double-acting cylinder. The technical feasibility of the process has been verified, with specific energy consumption fluctuating between 5 and 10 kWhsol.m-3. In both cases, modelling is carried out and validated on the basis of experimental results. By coupling the two technologies, it is possible to generate the permeate required for drinking water, and to disinfect the concentrate using the pasteurization process. This disinfection system combines energy efficiency with zero waste
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Yang, Clara Chih-Chieh. "Web dynamics : modeling, simulation, and experimentation". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38153.
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Cukalovic, Boris. "MIT integrated microelectronics device experimentation and simulation iLab". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36776.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 57-58).
We developed the MIT Integrated Microelectronics Device Experimentation and Simulation iLab, a new online laboratory that combines and significantly upgrades the capabilities of two existing online microelectronics labs: WebLab, a device characterization lab, and WebLabSim, a device simulation lab. The new integrated tool allows users to simultaneously run experiments on actual devices and simulations on the virtual ones, as well as to compare the results of the two. In order to achieve this, we considerably extended the capabilities of the original clients. We added the ability to graph the results of multiple experiments and simulations simultaneously, on top of each other, which allows for much easier comparison. We also added the ability to load, view and graph the results of experiments and simulations that were ran at any point in the past, even when the corresponding lab configurations are no longer available. Our hope is that this new integrated iLab will enrich microelectronics teaching and learning by allowing students to compare real life device behavior with theoretical expectations.
by Boris Cukalovic.
M.Eng.
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Z'Graggen, Andreas. "Solar gasification of carbonaceous materials : reactor design, modeling and experimentation /". kostenfrei, 2008. http://e-collection.ethbib.ethz.ch/view/eth:30596.
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Jin, Qiang. "SimGest: A simulation experimentation environment and a program generator for interactive simulation". Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6844.
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A good methodology for simulation experimentation can result in high efficiency in carrying out simulation experiments. To fully support a user to carry out a simulation experiment, a supportive and user friendly simulation experimentation environment is desirable. The program generator which generates the executable programs from a model expressed in a high-level simulation programming language is another important issue in simulation experimentation. This thesis presents a new methodology for simulation experimentation based on the model specification language Gest. A simulation experimentation environment which supports a user to carry out the simulation experiment based on the model written in Gest is implemented. A program generator which analyzes the model and generates an executable simulation program with simulation tables for the simulation experimentation environment is also discussed.
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Leidig, Jonathan Paul. "Epidemiology Experimentation and Simulation Management through Scientific Digital Libraries". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/28759.
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Advances in scientific data management, discovery, dissemination, and sharing are changing the manner in which scientific studies are being conducted and repurposed. Data-intensive scientific practices increasingly require data management related services not available in existing digital libraries. Complicating the issue are the diversity of functional requirements and content in scientific domains as well as scientists' lack of expertise in information and library sciences.
Researchers that utilize simulation and experimentation systems need digital libraries to maintain datasets, input configurations, results, analyses, and related documents. A digital library may be integrated with simulation infrastructures to provide automated support for research components, e.g., simulation interfaces to models, data warehouses, simulation applications, computational resources, and storage systems. Managing and provisioning simulation content allows streamlined experimentation, collaboration, discovery, and content reuse within a simulation community. Formal definitions of this class of digital libraries provide a foundation for producing a software toolkit and the semi-automated generation of digital library instances.
We present a generic, component-based SIMulation-supporting Digital Library (SimDL) framework. The framework is formally described and provides a deployable set of domain-free services, schema-based domain knowledge representations, and extensible lower and higher level service abstractions. Services in SimDL are specialized for semi-structured simulation content and large-scale data producing infrastructures, as exemplified in data storage, indexing, and retrieval service implementations. Contributions to the scientific community include previously unavailable simulation-specific services, e.g., incentivizing public contributions, semi-automated content curating, and memoizing simulation-generated data products. The practicality of SimDL is demonstrated through several case studies in computational epidemiology and network science as well as performance evaluations.Ph. D.
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Wagner, Albert W. "Electrochemical facilitated transport: a study in synthesis, simulation and experimentation". Diss., Virginia Tech, 1995. http://hdl.handle.net/10919/39106.
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Schunk, Lothar Oliver. "Solar thermal dissociation of zinc oxide : reaction kinetics, reactor design, experimentation, and modeling /". Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18041.
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Xu, Yijia. "A SIMULATION PLATFORM FOR EXPERIMENTATION AND EVALUATION OF DISTRIBUTED-COMPUTING SYSTEMS". Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1229%5F1%5Fm.pdf&type=application/pdf.
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Tipton, Austin L. "Simulation, Experimentation, Control and Management of a Novel Fuel Thermal System". Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1578320719632833.
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Donnadille, Philippe. "Comportement de gouttes en écoulement turbulent instationnaire : simulation numérique, modélisation, experimentation". Valenciennes, 1992. https://ged.uphf.fr/nuxeo/site/esupversions/65515773-7bc6-415c-8beb-98e07fbcb3d7.
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Le travail présenté dans cette thèse concerne l'étude de l'influence de fortes instationnarités d'écoulement sur la dispersion de gouttes. Le sujet est abordé selon les trois aspects suivants: simulation numérique, modélisation, expérimentation qui sont appliqués à deux géométries de base: marche descendante, zone de mélange. Des moyens originaux de visualisation, traitement d'image, et mesure sont utilisés pour caractériser l'écoulement: trajectographie de gouttes par vidéo rapide, anemogranulométrie par technique phase doppler. La simulation numérique: approche déterministe instationnaire lagrangienne pour la phase liquide, couplés a un calcul instantané de la phase gazeuse, est validée par l'expérience. Cinq approches stochastiques sont ensuite mises en œuvre pour la phase liquide (couplées à un calcul k-) et comparées aux approches précédentes. Une première analyse relative aux performances de ces différents modèles est présentée.
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Nygren, Martin Alexander. "Solar Simulation for the NTNU Test Satellite Solar Cells". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24434.
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The relevant energy theory behind intensity and spectral irradiance from the sun is discussed with regard to how it changes due to factors like Earth-Sun distance, solid angle of the sun disk and circumsolar region, angle of incidence and atmospheric mass. This translates to how the experienced conditions for solar cells vary, how and why solar simulation is done the way it is with such stringent requirements, as well as what can be expected in terms of difference between controlled, fixed conditions and operation in environments where we are not free to modify the variables as easily. The most essential theory of solar cell structure and performance is reviewed, with emphasis on the theory needed to understand the design principles, characteristics and behavior of the high-efficiency multijunction solar cells available for the NUTS project. The most commonly encountered components of a solar simulator is discussed to the point where the information provided should allow for a well-informed evaluation and selection of design for most applications, and be of guidance if one were to wish to attempt to create a device able to simulate aspects of the solar irradiation.Solar cell characteristics are developed by the use of a solar simulator under controlled testing conditions to ensure reproducible results. The effect of controlled sunlight from a range of different angles onto a solar cell is investigated in terms of current-voltage characteristics, and in particular the effect on short circuit current as compared to what is expected of theory. It is found that the angle of incidence of light can be calculated from the measured current with a general accuracy of about 1 degree, when compensating for reflectivity in the solar cell cover glass.
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Nadjahi, Chayan. "Passive cooling of data centers : modeling and experimentation". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC269.
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L'objectif de cette étude est de concevoir un système de refroidissement passif au sein d'un data center. La solution qui a été choisie est la boucle thermosiphon, combinant le free cooling et le refroidissement par changement de phase. Cette technologie offre de la simplicité et de la compacité. De plus, en l'associant avec des échangeurs de chaleur à micro-canaux, elle est capable d'absorber de grandes quantités de flux de chaleur avec un faible débit du réfrigérant. La boucle thermosiphon est composée d'un évaporateur à mini-canaux et à courants parallèles, d'un condenseur à air, d'un riser et d'un downcomer. Un prototype expérimental a été construit afin de caractériser les transferts de chaleur entre le réfrigérant et la chaleur créée. Des études expérimentales sont introduites. L'influence du taux de chargement et de la puissance électrique est détaillée et analysée. En parallèle, un modèle numérique a été développé pour prédire les caractéristiques du réfrigérant en fonction des paramètres géométriques et climatiques. Une comparaison avec les résultats expérimentaux est également effectuée. Enfin, la boucle thermosiphon est améliorée avec l'ajout d'un second évaporateur. Les tests sont effectués avec des puissances plus importantes. Une nouvelle conception d'une boucle thermosiphon et les limites du prototype sont présentéesThe objective of this study is to build a passive cooling system in a data center. The chosen solution is the loop thermosyphon, combining free cooling and two-phase cooling. This technology offers simplicity and compactness. Furthermore, by associating with micro-channels heat exchangers, it is able to remove higher heat fluxes while working with smaller mass flow rate of coolant. The thermosyphon is composed by mini-channel parallel-flow evaporator, an air condenser, a riser and a downcomer. The experimental setup has been built to characterize the heat transfer between the working fluid and the provided heat. An experimental study is introduced. The effect of the fill ratio and the input power is specified and analyzed. In parallel, a numerical model has been developed to predict the fluid properties in function of geometrical and climatic parameters. A comparison between experimental and numerical results is also carried out. Finally, the loop thermosyphon is upgraded with a second mini-channel parallel flow evaporator. Tests are conducted with huger heat flux. A new design of loop thermosyphon and the limits of the prototype are introduced
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Heffernan, Matthew Evan Bevly David M. "Simulation, estimation, and experimentation of vehicle longitudinal dynamics that effect fuel economy". Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/HEFFERNAN_MATTHEW_41.pdf.
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Hembise, Odile. "Etude d'un penetreur balistique des fonds marins : conception, optimisation, realisation, simulation, experimentation". Paris 6, 1987. http://www.theses.fr/1987PA066816.
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Description d'un penetreur balistique instrumente pour des mesures in-situ durant et apres penetration dans les sediments argileux des fonds marins a des profondeurs d'environ 6000 metres. Cette etude necessite des developpements theoriques, technologiques et experimentaux dans les domaines de l'hydrodynamique (vitesse limite, stabilite), des techniques d'acquisition et de mesures (capteurs hyperbares) et de la dynamique des sols (penetration). Optimisation de la geometrie des penetreurs par une approche numerique puis verification exprimentale en bassin d'essais puis en mer. Modelisation de la penetration. Mise en evidence des relations entre proprietes geotechniques des sols et parametres cinematiques du penetreur
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Younas, Mohammad. "Modélisation dynamique des contacteurs membranaires pour l'extraction liquide-liquide : experimentation et simulation". Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20002/document.
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Cette étude porte sur la modélisation dynamique d'un pilote d'extraction liquide-liquide avec des contacteurs membranaires à fibres creuses. L'objectif de ce travail est donc le développement d'un outil de modélisation afin d'optimiser des contacteurs membranaires à fibres creuses pour l'extraction liquide-liquide dans deux applications différentes : l'extraction d'arômes et de cuivre des solutions aqueuses. Un modèle axial-radial et à fibre unique basé sur une analyse des résistances en série ont été décrits. Il a aussi été développé un modèle en régime transitoire capable de prédire la concentration en soluté dans les réservoirs d'alimentation en fonction du temps. Ces deux modèles ont été couplés afin de former un modèle dynamique intégré pour l'extraction liquide-liquide avec une unité membranaire. Une étude expérimentale a permis de déterminer le mécanisme d'extraction avec plusieurs systèmes et solvants et ainsi valider le modèle dynamique intégré. Le modèle a permis ensuite la détermination de l'influence de divers paramètres comme la configuration, la structure des membranes, l'hydrodynamique et les conditions de transport ou opératoires sur l'efficacité de la vitesse d'extractionThe current study deals with the dynamic modelling of hollow fiber membrane contactor extraction plant. The objective of the study is to develop a simulation tool in order to optimize the membrane contactors for liquid-liquid extraction in two different applications: aroma and copper extraction from aqueous solutions. Axial-radial stage and single-fiber model of hollow fiber membrane contactor have been proposed based on resistance-in-series model. A separate dynamic model across reservoir has been developed based on macroscopic unsteady state mass transfer balance. Both models are, then, coupled to consolidate into an integrated dynamic model of the membrane-based solvent extraction plant. Experiments have been carried out to verify the reaction mechanism of various solvent extraction systems and to validate the integrated dynamic model. Model has been used to determine the influence of different module configurations, membrane structural para meters, hydrodynamic, transport and operating conditions upon the extraction efficiency and speed of extraction
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Mabie, Kevin T. "Solar simulation laboratory description and manual". Thesis, Monterey, California. Naval Postgraduate School, 1985. http://hdl.handle.net/10945/21549.
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Anderson, Tom Harper. "Optoelectronic simulation of nonhomogeneous solar cells". Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25892.
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This thesis investigates the possibility of enhancing the efficiency of thin film solar cells by including periodic material nonhomogeneities in combination with periodically corrugated back reflectors. Two different types of solar cell are investigated; p-i-n junctions solar cells made from alloys of hydrogenated amorphous silicon (a-Si:H) (containing either carbon or germanium), and Schottky barrier junction solar cells made from alloys of indium gallium nitride (InξGa1-ξN). Material nonhomogeneities are produced by varying the fractions of the constituent elements of the alloys. For example, by varying the content of carbon or germanium in the a-Si:H alloys, semiconductors with bandgaps ranging from 1:3 eV to 1:95 eV can be produced. Changing the bandgap alters both the optical and electrical properties of the material so this necessitates the use of coupled optical and electrical models. To date, the majority of solar cell simulations either prioritise the electrical portion of the simulation or they prioritise the optical portion of the simulation. In this thesis, a coupled optoelectronic model, developed using COMSOL Multiphysics®, was used to simulate solar cells: a two-dimensional finite-element optical model, which solved Maxwell's equations throughout the solar cells, was used to calculate the absorption of incident sunlight; and a finite-element electrical drift-diffusion transport model, either one- or two-dimensional depending on the symmetries of the problem, was used to calculate the steady state current densities throughout the solar cells under external voltage biases. It is shown that a periodically corrugated back reflector made from silver can increase efficiency of an a-Si:H alloy single p-i-n junction solar cell by 9:9% compared to a baseline design, while for a triple junction the improvement is a relatively meagre 1:8%. It is subsequently shown that the efficiency of these single p-i-n junction solar cells with a back reflector can be further increased by the inclusion of material nonhomogeneities, and that increasing the nonhomogeneity progressively increases efficiency, especially in thicker solar cells. In the case of InξGa1-ξN Schottky barrier junction solar cells, the gains are shown to be even greater. An overall increase in efficiency of up to 26:8% over a baseline design is reported.
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BUGNON, DENIS. "Simulation de la pharmacocinetique humaine des antibiotiques in vivo". Nantes, 1997. http://www.theses.fr/1997NANT10VS.
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BUGNON, DENIS. "Methode de simulation de la pharmacocinetique humaine chez l'animal : nouvelle technique et son application aux aminoglycosides". Nantes, 1991. http://www.theses.fr/1991NANT120M.
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Watson, J. W. "Investigation of cyclist and pedestian impacts with motor vehicles using experimentation and simulation". Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/5615.
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Physical tests were performed with a bicycle and a dummy in a controlled laboratory environment to reproduce cyclist accidents. The kinematics of 13 sled tests were used to identify the cyclist head impact location, understand the interaction between the cyclist and bicycle and to validate a mathematical model. The finite element software code LS-DYNA was used to simulate 70 cyclist and pedestrian accidents with motor vehicles with four different vehicle shapes which supplemented the physical testing. The study has shown that when cyclists and pedestrians were struck by any of the vehicles their whole body kinematics can be distinguished into two phases, initially a rotation followed by a sliding action. The Sports Utility Vehicle (SUV) vehicle produced more of a rotation action rather than sliding, whereas the other vehicles produced a combination of the two. The current pedestrian legislation does not cover all head impact locations for cyclists and therefore needs to be extended to encompass the windscreen and A-Pillar regions of the vehicles. The wrap around distance (WAD) for all the vehicles, apart from the SUV, should be extended to encompass a larger region. For the SUV the current WAD region is adequate in protecting cyclists and pedestrians and does not need to change. The predicted head impactor angle for cyclists is 40 degrees which is lower than the current legislative value of 65 degrees and the predicted pedestrian head impact angle is higher at a value of 80 degrees for the MPV, SM and LFC. For the SUV the proposed impactor angle increased to 100 degrees for cyclists and pedestrians. This research has demonstrated significant differences in terms of input variables and outcomes between cyclist and pedestrian accidents involving vehicles. It has used mathematical models to obtain injury data from a human mathematical model and physical testing to replicate real world cyclist accident scenarios. Recommendations have been proposed for future legislative testing techniques for cyclists, based on existing pedestrian legislation. These recommendations to alter legislation will improve vehicle design and make future vehicles more cyclist-friendly.
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BENHLIMA, SAID. "Identification des parametres dynamiques des systemes mecaniques articules complexes. Aspects : simulation et experimentation". Paris, ENSAM, 1993. http://www.theses.fr/1993ENAM0009.
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Les travaux exposes dans cette these ont pour but essentiel, la realisation d'une methode generale et systematique pour l'identification des parametres dynamiques des robots et sa concretisation experimentalement. La methode adoptee est basee sur l'observation et l'analyse des entrees/sorties du robot. Pour la mettre en uvre, une etape preliminaire et necessaire nous a conduit a developper les aspects theoriques de la modelisation des systemes mecaniques articules, en liaison avec l'identification. Le modele dynamique obtenu a ete augmente de la partie actionneurs. Une etude detaillee des phenomenes stochastiques a ete menee. Nous avons montre que l'identification est un probleme informationnel, dependant du type de la commande, de la chaine d'acquisition et des trajectoires utilisees lors du processus d'identification. Pour augmenter la precision des resultats de l'identification (minimiser le biais) et assurer sa robustesse, nous avons propose les solutions adequates pour chaque type de probleme rencontre: regroupement des parametres redondants par une methode soit numerique soit symbolique, blocage des parametres mal eclaires, developpement d'une nouvelle methode, simple et proche de la realite industrielle, pour la recherche des trajectoires excitantes. Enfin, nous avons concretise nos travaux par un logiciel roboide realisant automatiquement toutes les etapes de la procedure d'identification. Pour illustrer cette methode generale, nous l'avons valide en simulation et en experience pour le cas du robot mac de l'ensam. Les resultats experimentaux de l'identification nous ont permis de montrer que l'erreur de modelisation des couples a ete reduite de 86% par rapport aux couples nominaux
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Leonard, Robert D. "Considerations for Screening Designs and Follow-Up Experimentation". VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3928.
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The success of screening experiments hinges on the effect sparsity assumption, which states that only a few of the factorial effects of interest actually have an impact on the system being investigated. The development of a screening methodology to harness this assumption requires careful consideration of the strengths and weaknesses of a proposed experimental design in addition to the ability of an analysis procedure to properly detect the major influences on the response. However, for the most part, screening designs and their complementing analysis procedures have been proposed separately in the literature without clear consideration of their ability to perform as a single screening methodology.
As a contribution to this growing area of research, this dissertation investigates the pairing of non-replicated and partially–replicated two-level screening designs with model selection procedures that allow for the incorporation of a model-independent error estimate. Using simulation, we focus attention on the ability to screen out active effects from a first order with two-factor interactions model and the possible benefits of using partial replication as part of an overall screening methodology. We begin with a focus on single-criterion optimum designs and propose a new criterion to create partially replicated screening designs. We then extend the newly proposed criterion into a multi-criterion framework where estimation of the assumed model in addition to protection against model misspecification are considered. This is an important extension of the work since initial knowledge of the system under investigation is considered to be poor in the cases presented. A methodology to reduce a set of competing design choices is also investigated using visual inspection of plots meant to represent uncertainty in design criterion preferences. Because screening methods typically involve sequential experimentation, we present a final investigation into the screening process by presenting simulation results which incorporate a single follow-up phase of experimentation. In this concluding work we extend the newly proposed criterion to create optimal partially replicated follow-up designs. Methodologies are compared which use different methods of incorporating knowledge gathered from the initial screening phase into the follow-up phase of experimentation.
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Pendyala, Raghu Kishore. "Automated Simulation of Organic Photovoltaic Solar Cells". Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-15338.
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This project is an extension of a pre-existing simulation program (‘Simulation_2dioden’). This simulation program was first developed in Konarka Technologies. The main purpose of the project ‘Simulation_2dioden’ is to calibrate the values of different parameters like, Shunt resistance, Series resistance, Ideality factor, Diode current, epsilon, tau, contact probability, AbsCT, intensity, etc; This is one of the curve fitting procedure’s. This calibration is done by using different equations. Diode equation is one of the main equation’s used in calculating different currents and voltages, from the values generated by diode equation all the other parameters are calculated.
The reason for designing this simulation_2dioden is to calculate the values of different parameters of a device and the researcher would know which parameter effects more in the device efficiency, accordingly they change the composition of the materials used in the device to acquire a better efficiency. The platform used to design this project is ‘Microsoft Excel’, and the tool used to design the program is ‘Visual basics’. The program could be otherwise called as a ‘Virtual Solar cell’. The whole Virtual Solar cell is programmed in a single excel sheet.
An Automated working solution is suggested which could save a lot of time for the researchers, which is the main aim of this project. To calibrate the parameter values, one has to load the J-V characteristics and simulate the program by just clicking one button. And the parameters extracted by using this automated simulation are Parallel resistance, Series resistance, Diode ideality, Saturation current, Contact properties, and Charge carrier mobility.
Finally, a basic working solution has been initiated by automating the simulation program for calibrating the parameter values.
26
Shariff, A. "Computer simulation of amorphous silicon solar cells". Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638814.
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A detailed numerical model of the electronic properties of hydrogenated amorphous silicon has been developed and shown to be a useful tool for the analysis of the performance and optimization of the design of solar cells. The method of simulation involves solving Poissons's equation, and the electron and hole continuity equations, in conjunction with the transport equations for the electrons and holes. From the solutions of these equations we obtained the electrostatic potential, the electron and hole concentrations and the current densities. A set of realistic material parameters has been used. We have modelled the density of states to consist of two exponential band tails and the dangling bonds. Recombination in both the band tails and the dangling bonds has been taken into consideration in the model. We investigated the effect of the cell performance on varying dangling bond densities (1016cm-3-1017cm-3) for various cell thicknesses of p-i-n hydrogenated amorphous silicon solar cells, for incident blue and red light. Our results agree well with experiments for solar cells in the undegraded state. However for the degraded state the fill factors appear to be higher than the experimental values. This might be because we have only assumed a single level dangling bond density in our model. It is suggested that future work might undertake the incorporation of the spatial dependence of the dangling bond density in the model.
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Fialho, Luís André Pereira. "Photovoltaic generation with energy storage integrated into the electric grid: modelling, simulation and experimentation". Doctoral thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/25361.
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Esta tese apresenta o trabalho e resultados da investigação desenvolvida sobre conversão fotovoltaica com armazenamento de energia integrado em rede elétrica. Começa por apresentar a modelação, simulação e validação da conversão fotovoltaica e inversores com injeção para a rede. Descreve também seguidamente o processo de conceção, construção, comissionamento e desenvolvimento experimental das infraestruturas hoje existentes na Cátedra Energias Renováveis da Universidade de Évora, no que diz respeito às duas microgrids desenvolvidas no âmbito do projeto europeu PVCROPS. Estas microgrids são compostas, de forma geral, por um elemento de produção fotovoltaica, um elemento de armazenamento de energia, uma ligação à rede e um sistema de controlo e datalogging. Relativamente ao armazenamento de energia, esta tese aborda e caracteriza ainda as duas tecnologias instaladas: a bateria de iões de lítio e a bateria de fluxo redox de vanádio. Estas microgrids servem assim para implementação e validação de uma estratégia de gestão de energia tendo como objetivo a maximização do autoconsumo, cujos conteúdos são apresentados no capítulo 4. Depois das conclusões, no último capítulo, apontam-se ainda as linhas de investigação futuras de maior potencial, na sequência do trabalho desenvolvido e apresentado nesta tese; Photovoltaic generation with energy storage integrated into the electric grid: Modelling, simulation and experimentation
Abstract:
This thesis presents the work and results of the research developed on photovoltaic conversion with energy storage integrated into the electric grid. It begins by presenting the modeling, simulation and validation of the photovoltaic conversion and inverters with injection into the electric grid. It also describes the process of design, construction, commissioning and experimental development of the existing infrastructures in the Renewable Energies Chair of the University of Évora, with respect to the two microgrids developed under the European project PVCROPS. These microgrids are generally composed by a photovoltaic production element, an energy storage element, a grid connection and a control and datalogging system. Regarding energy storage, this thesis also discusses and characterizes the two installed technologies: the lithium-ion battery and the redox-flow vanadium battery. These microgrids thus serve to implement and validate an energy management strategy with the objective of maximizing self-consumption, the contents of which are presented in Chapter 4. Following the conclusions, in the last chapter are pointed the future research lines of greater potential, following the work developed and presented in this thesis.
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Ebel, Henrik [Verfasser]. "Distributed Control and Organization of Communicating Mobile Robots: Design, Simulation, and Experimentation / Henrik Ebel". Düren : Shaker, 2021. http://d-nb.info/1240853637/34.
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Miller, Emily Michele. "Exercise-Induced Low Back Pain and Neuromuscular Control of the Spine - Experimentation and Simulation". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/37507.
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Low back pain (LBP) is associated with altered neuromuscular control of the trunk, as well as impaired performance during functional tasks highly dependent upon trunk neuromuscular control. Comparing measurements between individuals with and without LBP does not distinguish whether the LBP individual exhibits altered neuromuscular control only while experiencing LBP versus at all times. Additional insight was gained on the relationship between trunk neuromuscular control and LBP by investigating individuals who experience recurrent exercise-induced LBP (eiLBP). To differentiate the effects of LBP from individual differences, comparisons were made between episodes of pain and no pain within eiLBP individuals, and between eiLBP individuals while pain free and a group of healthy controls. Three studies were completed based on repeated measurements from both eiLBP and healthy individuals. Study 1 investigated effects of eiLBP on fundamental measures of neuromuscular control, including intrinsic trunk stiffness and the paraspinal reflex delay using a series of pseudo-random position perturbations. eiLBP individuals exhibited increased stiffness compared to healthy controls unaffected by the presence of pain, and increased reflex delays concurrent only with pain. Study 2 investigated effects of eiLBP on seated sway during a functional task involving maintaining balance. Seat and trunk kinematics were obtained while participants balanced on a wobble chair at two difficulty levels. eiLBP individuals exhibited impaired seat measures at all times, with altered trunk measures only while in pain and when the task was not challenging. Study 3 investigated effects of eiLBP on the underlying control of seated sway using a model of wobble chair balance. Quantified neuromuscular control indicated increases in proportional and noise gains for a challenging level compared to an easy level, more so for eiLBP individuals compared to controls and while experiencing pain compared to pain free. Overall, fundamental measures, seated sway measures, and identified control parameters using a model of wobble chair balance were all affected by the presence of pain within the eiLBP individuals and/or the eiLBP individuals compared to healthy controls. Therefore, this study shows that some characteristics appear to be inherent to the LBP individual, while others are only concurrent with pain.Ph. D.
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Lea, Roy Kim. "A comparative study by simulation and experimentation of control techniques for autonomous underwater flight vehicles". Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264389.
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Bartsch, Adam Jesse. "Biomechanical Engineering Analyses of Head and Spine Impact Injury Risk via Experimentation and Computational Simulation". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1291318455.
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Edwards, Thomas. "Optimisation of coated nanowire solar cells by simulation". Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/34928.
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Radial junction nanowire solar cells are expected to give a higher performance than planar junction solar cells. This is due to the enhanced optical path length for absorption, and the shorter distance for excitons to travel to interfaces where they can dissociate. By means of simulation, we have optimised, with respect to geometrical parameters, solar cells consisting of light absorber coated metal- oxide nanowires. We have primarily studied nanowires with a TiO2 core and CdSe shell, as well as ZnO cores with PbS nanoparticles. Optical scattering and absorption is determined using Finite-Difference Time-Domain (FDTD) simulations. Charge transport is studied using finite-difference drift-diffusion modelling. The generation rate calculated from FDTD is inputted into the charge transport model. The aim is to determine which combination of nanowire parameters (such as coating thickness, height, radius and spacing) lead to the the highest power efficiencies. We found that core and shell thickness has more effect on absorption than nanowire arrangement.
33
Sweet, Marshall. "Numerical Simulation of Underground Solar Thermal Energy Storage". VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2322.
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The United States Department of Energy indicates that 97% of all homes in the US use fossil fuels either directly or indirectly for space heating. In 2005, space heating in residential homes was responsible for releasing approximately 502 million metric tons of carbon dioxide into the atmosphere. Meanwhile, the Sun provides the Earth with 1000 watts per square meter of power everyday. This document discusses the research of modeling a system that will capture and store solar energy during the summer for use during the following winter. Specifically, flat plate solar thermal collectors attached to the roof of a single family home will collect solar thermal energy. The thermal energy will then be stored in an underground fabricated Seasonal Solar Thermal Energy Storage (SSTES) bed. The SSTES bed will allow for the collected energy to supplement or replace fossil fuel supplied space heat in typical single family homes in Richmond, Virginia. TRNSYS is a thermal energy modeling software package that was used to model and simulate the winter thermal load of a typical Richmond home. The simulated heating load was found to be comparable to reported loads for various home designs. TRNSYS was then used to simulate the energy gain from solar thermal collectors and stored in an underground, insulated, vapor proof SSTES bed filled with sand. Combining the simulation of the winter heat demand of typical homes and the SSTES system showed reductions in fossil fuel supplied space heating in excess of 64%.
34
Zanuccoli, Mauro <1974>. "Advanced Numerical Simulation of Silicon-Based Solar Cells". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4566/1/Zanuccoli_Mauro_tesi.pdf.
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Photovoltaic (PV) conversion is the direct production of electrical energy from sun without involving the emission of polluting substances. In order to be competitive with other energy sources, cost of the PV technology must be reduced ensuring adequate conversion efficiencies. These goals have motivated the interest of researchers in investigating advanced designs of crystalline silicon solar (c-Si) cells. Since lowering the cost of PV devices involves the reduction of the volume of semiconductor, an effective light trapping strategy aimed at increasing the photon absorption is required. Modeling of solar cells by electro-optical numerical simulation is helpful to predict the performance of future generations devices exhibiting advanced light-trapping schemes and to provide new and more specific guidelines to industry. The approaches to optical simulation commonly adopted for c-Si solar cells may lead to inaccurate results in case of thin film and nano-stuctured solar cells. On the other hand, rigorous solvers of Maxwell equations are really cpu- and memory-intensive. Recently, in optical simulation of solar cells, the RCWA method has gained relevance, providing a good trade-off between accuracy and computational resources requirement. This thesis is a contribution to the numerical simulation of advanced silicon solar cells by means of a state-of-the-art numerical 2-D/3-D device simulator, that has been successfully applied to the simulation of selective emitter and the rear point contact solar cells, for which the multi-dimensionality of the transport model is required in order to properly account for all physical competing mechanisms. In the second part of the thesis, the optical problems is discussed. Two novel and computationally efficient RCWA implementations for 2-D simulation domains as well as a third RCWA for 3-D structures based on an eigenvalues calculation approach have been presented. The proposed simulators have been validated in terms of accuracy, numerical convergence, computation time and correctness of results.La conversione fotovoltaica è la produzione diretta di energia elettrica dal sole che non comporta l'emissione di sostanze inquinanti. Al fine di competere con altre fonti di energia, la tecnologia fotovoltaica deve subire una riduzione del costo garantendo contemporaneamente adeguate efficienze di conversione. Questi obiettivi hanno motivato l'interesse dei ricercatori al progetto ed all'analisi di celle solari avanzate in silicio cristallino. Poiché la riduzione del costo dei dispositivi fotovoltaici comporta tipicamente la riduzione del volume di semiconduttore, è necessaria una strategia efficace di intrappolamento della luce per aumentare l'assorbimento dei fotoni. Gli approcci orientati alla simulazione ottica comunemente adottati per la celle solari in silicio cristallino possono condurre a risultati non accurati in caso di celle a film sottile e nanostrutturate. D'altra parte, i risolutori rigorosi delle equazioni di Maxwell sono altamente onerosi in termini computazionali. Recentemente, nella simulazione ottica di celle solari, il metodo RCWA ha acquisito una forte popolarità, fornendo un buon compromesso tra accuratezza e fabbisogno di risorse computazionali. Questa tesi rappresenta un contributo alla simulazione numerica -sia ottica che elettrica- di celle solari avanzate al silicio. Un simulatore numerico di dispositivi a semiconduttore 2-D/3-D allo stato dell'arte è stato applicato con successo alla simulazione di celle a doppia diffusione di emettitore a di celle con superficie posteriore passivata e contatto locale, per le quali è richiesta la multi-dimensionalità del modello di trasporto al fine di descrivere correttamente tutti i meccanismi fisici. Nella seconda parte della tesi, vengono discussi gli aspetti relativi alla simulazione ottica. Due innovative e computazionalmente efficienti implementazioni del metodo RCWA per domini di simulazione 2-D nonché un terzo simulatore RCWA per strutture 3-D basato sul calcolo di autovalori sono stati presentati in questa tesi. I simulatori proposti sono stati validati in termini di accuratezza, convergenza numerica, tempo di calcolo e correttezza dei risultati.
35
Zanuccoli, Mauro <1974>. "Advanced Numerical Simulation of Silicon-Based Solar Cells". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4566/.
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Photovoltaic (PV) conversion is the direct production of electrical energy from sun without involving the emission of polluting substances. In order to be competitive with other energy sources, cost of the PV technology must be reduced ensuring adequate conversion efficiencies. These goals have motivated the interest of researchers in investigating advanced designs of crystalline silicon solar (c-Si) cells. Since lowering the cost of PV devices involves the reduction of the volume of semiconductor, an effective light trapping strategy aimed at increasing the photon absorption is required. Modeling of solar cells by electro-optical numerical simulation is helpful to predict the performance of future generations devices exhibiting advanced light-trapping schemes and to provide new and more specific guidelines to industry. The approaches to optical simulation commonly adopted for c-Si solar cells may lead to inaccurate results in case of thin film and nano-stuctured solar cells. On the other hand, rigorous solvers of Maxwell equations are really cpu- and memory-intensive. Recently, in optical simulation of solar cells, the RCWA method has gained relevance, providing a good trade-off between accuracy and computational resources requirement. This thesis is a contribution to the numerical simulation of advanced silicon solar cells by means of a state-of-the-art numerical 2-D/3-D device simulator, that has been successfully applied to the simulation of selective emitter and the rear point contact solar cells, for which the multi-dimensionality of the transport model is required in order to properly account for all physical competing mechanisms. In the second part of the thesis, the optical problems is discussed. Two novel and computationally efficient RCWA implementations for 2-D simulation domains as well as a third RCWA for 3-D structures based on an eigenvalues calculation approach have been presented. The proposed simulators have been validated in terms of accuracy, numerical convergence, computation time and correctness of results.La conversione fotovoltaica è la produzione diretta di energia elettrica dal sole che non comporta l'emissione di sostanze inquinanti. Al fine di competere con altre fonti di energia, la tecnologia fotovoltaica deve subire una riduzione del costo garantendo contemporaneamente adeguate efficienze di conversione. Questi obiettivi hanno motivato l'interesse dei ricercatori al progetto ed all'analisi di celle solari avanzate in silicio cristallino. Poiché la riduzione del costo dei dispositivi fotovoltaici comporta tipicamente la riduzione del volume di semiconduttore, è necessaria una strategia efficace di intrappolamento della luce per aumentare l'assorbimento dei fotoni. Gli approcci orientati alla simulazione ottica comunemente adottati per la celle solari in silicio cristallino possono condurre a risultati non accurati in caso di celle a film sottile e nanostrutturate. D'altra parte, i risolutori rigorosi delle equazioni di Maxwell sono altamente onerosi in termini computazionali. Recentemente, nella simulazione ottica di celle solari, il metodo RCWA ha acquisito una forte popolarità, fornendo un buon compromesso tra accuratezza e fabbisogno di risorse computazionali. Questa tesi rappresenta un contributo alla simulazione numerica -sia ottica che elettrica- di celle solari avanzate al silicio. Un simulatore numerico di dispositivi a semiconduttore 2-D/3-D allo stato dell'arte è stato applicato con successo alla simulazione di celle a doppia diffusione di emettitore a di celle con superficie posteriore passivata e contatto locale, per le quali è richiesta la multi-dimensionalità del modello di trasporto al fine di descrivere correttamente tutti i meccanismi fisici. Nella seconda parte della tesi, vengono discussi gli aspetti relativi alla simulazione ottica. Due innovative e computazionalmente efficienti implementazioni del metodo RCWA per domini di simulazione 2-D nonché un terzo simulatore RCWA per strutture 3-D basato sul calcolo di autovalori sono stati presentati in questa tesi. I simulatori proposti sono stati validati in termini di accuratezza, convergenza numerica, tempo di calcolo e correttezza dei risultati.
36
NURZIA, Giovanni. "Design and simulation of solar absorption cooling systems". Doctoral thesis, Università degli studi di Bergamo, 2008. http://hdl.handle.net/10446/51.
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The aim of this work is to improve the modeling of single stage absorption chillers and to asses a design procedure for solar cooling systems based on computer simulations. The absorption technology is reviewed in its fundamentals, with an effort on the phenomena that might be considered or not in a physical model. A basic version of the absorption chiller model, which assumes that the heat transfer characteristics of the standard components do not depend on working conditions, is applied to simulate generic commercial chillers. The procedure outlined requires the knowledge of the nominal working
condition of the chiller, a data which is usually available from manufacturers. The model applied to the simulation of a chiller produced by the Thermax company shows good agreement with the off design
curves declared by the manufacturer. The hypotheses of this basic model are then reviewed, in order to catch some important aspects in the simulation of the Yazaki WFC-10 chiller. It is the first attempt, and therefore susceptible of improvement, to model the entire Yazaki chiller taking into account the behaviour of its heat exchangers. A compromise between theoretical modeling and experimental correlations has been adopted, due to the complexity of the chiller and its barely accessible patented design. Some encouraging results have been obtained, but they point out that further research on the heat and
mass transfer phenomena in the Yazaki absorption chiller is needed.
The absorption chiller modeling is then exploited in a computer tool that gives valuable information on the planning of solar cooling systems. The design of these systems involves the choice of the main components, their sizing and an adequate control strategy of the whole. Several installations are present worldwide, but there is a lack of standard planning methodology. In the present thesis the focus is on the choice of the plant elements and their sizing. Energy savings and economic competitiveness are regarded as essential in guiding the design process. To find out an ideal sizing of the system the
optimization-simulation approach is introduced. Once a typical system layout is chosen the TRNSYS environment is employed to see how different sizes of the system components effect the overall energy performance. The main design variables considered are the orientation of the solar collector array, the collectors area, the nominal capacity of the absorption chiller, the nominal capacity of the back up compression chiller, the volume of the thermal storages. Several simulations are launched by an external optimization programme, that retrieves the value of an objective function and changes the variables consequently. The procedure has been applied to a real planning case, carried out in two different installation sites. The results show that the economic convenience of solar cooling systems is really not easy going in the present scenario. Primary energy savings and reduction of electrical peak loads during hot season.
Finally a section of the present work describes how the absorption cycle model can be exploited to design a novel chiller. The allocation of the heat transfer area among the standard components of a chiller is analysed to get the best compromise between cost and thermodynamic performance. The geometry of each exchanger is optimized looking for a trade off between primary cost of the tubes and running cost of the pump employed in the external circuits.
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Courant, Bruno. "Fusion et carburation superficielles du titane par irradiation laser multi-impulsionnelle, modelisation thermique, experimentation et simulation". Paris, ENSAM, 1998. http://www.theses.fr/1998ENAM0036.
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La carburation superficielle du titane par fusion sous irradiation laser multi-impulsionnelle au moyen d'une source nd-yag pulsee est etudiee. Les caracteristiques optiques du faisceau, telles que divergence et distance focale, ainsi que la distribution spatiale d'energie dans le plan de focalisation sont determinees. Quatre parametres pertinents d'irradiation sont definis a partir des parametres operatoires. La modelisation des effets thermiques de l'irradiation donne acces aux champs thermiques dans le materiau et a leur evolution temporelle. Le modele semi-analytique propose prend en compte les enthalpies de transformation et il est adapte au caractere pulse de l'irradiation. Il est fonde sur la methode de resolution par les fonctions de green. Grace a cette modelisation, de nombreuses simulations des champs thermiques a divers instants sont effectuees. Les diverses zones fondues observees au microscopie se distinguent par leur epaisseur, variant de quelques micrometres a quelques centaines de micrometres, et par leur microstructure. La morphologie de la phase carbure tic#1##x varie avec la concentration de carbone dans la zone fondue. Pour des concentrations inferieures a 20 atomes %, les grains de carbure sont des dendrites cellulaires, preuve d'une surfusion constitutionnelle, tandis que pour des concentrations superieures, ils deviennent globulaires. Une relation entre le taux de superposition et la proportion de carbone incorpore est mise en evidence. En l'absence d'inclusions de graphite, la carburation superficielle du metal augmente la durete de maniere significative. Enfin, d'un point de vue tribologique, le titane traite par irradiation laser est susceptible de presenter un faible coefficient de frottement par glissement sur ceramique (0,2-0,3), accompagne d'une tres faible usure, grace a la formation d'un revetement composite auto-lubrifiant constitue de carbure de titane, de titane metallique et de graphite remplissant la fonction de lubrifiant solide.
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Magureanu, Andrei-Florin. "Solar Optimization in Urban Design". Thesis, KTH, Stadsbyggnad, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146982.
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The thesis attempts to construct a framework for urban design by finding an optimal balance between urban density and solar access. It presents the results of running a multiple objective optimization process on a predesigned urban grid, in order to find the spatial configuration that performs the best both urban density-wise and having the best facade radiation.
39
Roerig, Steven John. "Simulation of a solar powered electric vehicle under the constraints of the world solar challenge". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA294615.
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Kusyy, Oleh [Verfasser]. "Simulation-based optimization of solar thermal systems / Oleh Kusyy". Kassel : Universitätsbibliothek Kassel, 2018. http://d-nb.info/1174848464/34.
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Pongratananukul, Nattorn. "ANALYSIS AND SIMULATION TOOLS FOR SOLAR ARRAY POWER SYSTEMS". Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2565.
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This dissertation presents simulation tools developed specifically for the design of solar array power systems. Contributions are made in several aspects of the system design phases, including solar source modeling, system simulation, and controller verification. A tool to automate the study of solar array configurations using general purpose circuit simulators has been developed based on the modeling of individual solar cells. Hierarchical structure of solar cell elements, including semiconductor properties, allows simulation of electrical properties as well as the evaluation of the impact of environmental conditions. A second developed tool provides a co-simulation platform with the capability to verify the performance of an actual digital controller implemented in programmable hardware such as a DSP processor, while the entire solar array including the DC-DC power converter is modeled in software algorithms running on a computer. This "virtual plant" allows developing and debugging code for the digital controller, and also to improve the control algorithm. One important task in solar arrays is to track the maximum power point on the array in order to maximize the power that can be delivered. Digital controllers implemented with programmable processors are particularly attractive for this task because sophisticated tracking algorithms can be implemented and revised when needed to optimize their performance. The proposed co-simulation tools are thus very valuable in developing and optimizing the control algorithm, before the system is built. Examples that demonstrate the effectiveness of the proposed methodologies are presented. The proposed simulation tools are also valuable in the design of multi-channel arrays. In the specific system that we have designed and tested, the control algorithm is implemented on a single digital signal processor. In each of the channels the maximum power point is tracked individually. In the prototype we built, off-the-shelf commercial DC-DC converters were utilized. At the end, the overall performance of the entire system was evaluated using solar array simulators capable of simulating various I-V characteristics, and also by using an electronic load. Experimental results are presented.Ph.D.
Department of Electrical and Computer Engineering
Engineering and Computer Science
Electrical Engineering
42
Chen, Mingfei. "Computer simulation of Ringbom stirling engine with solar pond". Ohio University / OhioLINK, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1182285925.
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Alessandrini, Stefano. "Experimental analysis and dynamic simulation of solar cooling systems". Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/11128.
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2013/2014Il continuo aumento della richiesta di energia elettrica e la conseguente crescita dei valori di anidride carbonica nell'atmosfera terrestre crea sempre più la necessità di attuare modifiche sostanziali non solo nei metodi di produzione dei settori energetico e industriale, ma anche nella vita di ogni abitante del pianeta. Questa tesi analizza la possibilità di utilizzare l'energia solare per la produzione di acqua fredda grazie alla contemporaneità tra la disponibilità di energia rinnovabile e la richiesta di raffrescamento durante il periodo estivo. Due diversi impianti sperimentali, dotati di collettori solari a tubi evacuati commerciali e chiller ad adsoprbimento di piccole dimensioni (20 kW), sono stati monitorati ed i primi risultati sperimentali sono presentati in questo studio. Per studiare soluzioni diverse e trovare un design ottimale, un modello di simulazione dinamica è stato creato e testato utilizzando il software commerciale TRNSYS 17.
XXVII Ciclo
1984
44
Bryan, Kevin D. "Computer modeling of a concentrator solar cell". Virtual Press, 1989. http://liblink.bsu.edu/uhtbin/catkey/543982.
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The application of high speed computers to simulate physical devices has pioneered many scientific advances in recent times. With a suitable model to simulate their activity, solar cells are excellent candidates for such applications. In this work, a computer program has been developed which models an N+-P-P+ solar cell in one dimension. This model is structured to allow solar cells of different materials to be used in the program, however, only silicon is used here in order to demonstrate the capabilities of the program.For purposes of simplicity, the following conditions are assumed. All solar radiation enters the cell at normal incidence. The cell's temperature is uniform throughout and is considered a constant in all calculations. Doping concentrations in individual cell regions are uniform. Generation and recombination rates are also uniform within each of the cell's three regions. Items common to the two-dimensional cell but superficial to the one-dimensional cell such as contacts, lateral current flow, edge effects and variations of any type in the lateral direction are assumed to be non-existent.Background information for those not familiar with the topic is given followed by a presentation of the equations used. The general method of numerical calculation is then explained. Examples of program output are discussed along with an example application of the program. An entire program listing is given in appendix B.Department of Physics and Astronomy
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Brock, Andrew. "Aerospike Rocket Motor Structural Webbing". DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1355.
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A labscale hybrid rocket motor test stand has been developed for research at Cal Poly. The primary focus of research using this rig has been the development of regenerative cooling techniques using nitrous oxide as coolant and oxidizer, as well as validation of technologies relating to the annular aerospike nozzle. In order to prevent undesirable deflection of the cantilevered spike, a structural stiffening web, referred to as “The Spider,” is proposed. The Spider resembles a three-spoked wheel, with the aerospike held by the inner hub and the chamber walls abutting the outer radius.
The Spider, placed upstream of the nozzle, is subject to thermal loads due to radiation and convection from the gases, and conduction from the outer annulus, as well as mechanical loads from thermal expansion and gas flow. Simulation tools are developed in three phases to produce an accurate model of the spatio-temporal distribution of these loads.
A prototype of the Spider instrumented with thermocouple probes is designed, manufactured, and subjected to a series of hotfire tests. Results from three experimental runs are gathered and compared to simulated results. Good agreement is shown for the most part between the two datasets, with a single noticeable discrepancy for one measured temperature location. The high fidelity in the mean rate of temperature change for all stations indicates that the convective heat load is accurately modeled.
The simulation results, confirmed by experiment, indicate that in order for the Spider to survive in the steady-state during an actual burn, an active cooling strategy is necessary. Two actively cooled concept designs are presented and discussed, and future avenues of research are suggested.
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Chmielewski, Nicholas E. "Design, construction, and experimentation of a heat pipe augmented solar wall". 2009. http://etd.louisville.edu/data/UofL0476t2009.pdf.
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Thesis (M.Eng.)--University of Louisville, 2009.Title and description from thesis home page (viewed May 15, 2009). Department of Mechanical Engineering. Vita. "May 2009." Includes bibliographical references (p. 122-125).
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Huang, Chien-Yao, i 黃乾燿. "CIGS and Micromorph Solar Cell Simulation". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/30166890964750163829.
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碩士臺灣大學
光電工程學研究所
98
In this thesis, the physics of CIGS and micromorph solar cells are investigated by numerical simulation. At first, simulation models are established and compared with experiment results. Then some issues of high efficiency thin film solar cell are discussed. Among several thin film solar cells, CIGS solar cell has a record efficiency ~20%, but the progress has largely been driven by empirical optimization rather than by in-depth understanding of appropriate physical models. Therefore, some critical issues for achieving high conversion efficiency are discussed including(1) optimum single band gap of CIGS solar cell and the effects of CBO between CdS/CIGS layers; (2) effects of Ga-grading on CIGS solar cell; (3) effects of junction properties on CIGS solar cell. These simulation results give some insights to achieving high cell efficiency. Micromorph solar cell has a stack tandem structure and consists of an amorphous silicon top cell and a microcrystalline silicon bottom cell. The interconnection between top and bottom cells is via Esaki tunnel diode. The simulated J-V curve has an S-shape and 33.4 A/cm2 maximum tunnel current Jpeak, which is much greater than photo-generated current Jphoto to prevent distorted J-V curve. The optimal thickness of absorber layer is also discussed and indicates the efficiency of micromorph solar cell is sensitive to current matching. Furthermore, the EQE responses of subcells under different voltage bias are studied by simulation. The different behaviors of top and bottom cell are discussed and referred to difference of optical generation distribution. Finally, surface texture is considered into simulation model and optimizes the texture size. The optimal texture size gives a 2% efficiency improvement than planar structure.
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Ku, Chun-Yuan, i 古峻源. "Novel Hetero Structure Solar Cell Simulation". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/01875466944013995849.
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碩士臺灣大學
光電工程學研究所
98
In this thesis, to study hetero structure solar cell, we use TCAD to simulate characteristics of solar cell, try to improve the structure and get better efficiency. Open-circuit voltage of traditional wafer cell can be improved by thin film amorphous silicon. Dark current of this amorphous silicon/wafer heterojunction structure solar cell can be suppressed and gain serious improvement of open-circuit voltage. Thus efficiency will be dramatically increased. The optimization and modification of cell structure is also our focus. Except improvement of traditional back surface field (BSF), by using silicon germanium (SiGe) for materials of back surface field, additional short-circuit current can be gain. Compare to silicon, smaller bandgap of silicon germanium can absorb broaden spectrum. More carrier can be generated and makes contribution on short-circuit current. Even though heterojunction with intrinsic thin-layer (HIT) can improve efficiency, HIT has been submitted as Sanyo’s pattern, a Japanese company. To bypass the pattern, we propose a novel structure called “Hetero Emitter”. It can decrease serious dark current by reduction of recombination term. Due to dark current reduction, the efficiency of Hetero Emitter can surpass traditional wafer cell.
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Chang, Shun-Chieh, i 張舜傑. "Simulation of solar thermal storage tank". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/47023404040408385858.
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碩士淡江大學
化學工程與材料工程學系碩士班
100
This study use the GAMBIT to plan the geometric structure of the thermal storage tank, then use FLUENT to establish boundary condition, liquid properties, storage tank material. We read the data and the temperature contours by FLUENT. The storage tank volume is 490 L. The heat coil and cold coil heat exchangers in the storage tank. The rate of discharge is 0.235 L/min passes over in the heat coil, and the rate of discharge is 0.094 L/min passes over the cold coil. Using FLUENT to simulate different boundary conditions. The numerical simulation to compute, by the change of heat flow inlet temperature, hot stream and cold stream inlet flow rate, the contact area of coil and tank liquid. To understand temperature stratification in thermal storage tank and compared with simulation results in different boundary conditions.
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Chang, Wei-Chen, i 張瑋辰. "GaInP / Si Tandem Solar Cell Simulation". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/58988273838875034686.
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碩士國立中央大學
光電科學與工程學系
102
There are a variety of green energy. The solar cell is discussed the most. High efficiency and low cost are the goal. The theoretical efficiency of single silicon solar cell is 26%. The multijunction design is the way to get high efficiency. The best efficiency now is III-V multijunction solar cell, but III-V multijunction solar cell is expensive. We use III-V material which can enhance the absorption in specific wavelength, and the mature fabrication technology of silicon material. We simulate GaInP / Si tandem solar cell for high efficiency and low cost. First, we simulate and discuss the GaInP on Si substrate solar cell. We discuss the design of antireflection coating, the threading dislocation density, the bandgap of window layer, the recombination velocity in window / emitter interface, and the doping of window layer. The optimized result are listed below. The short current density is 14.4 mA/cm^2.The open circuit voltage is 1.316 V. The fill factor is 86.72 %. The efficiency is 16.44 %. Second, we discuss the GaInP / Si tandem solar cell. We discuss the overall antireflection coating, the top cell thickness for current match. We also discuss how the tunnel junction doping affects the whole solar cell. The optimized result are listed below. The result of the efficiency is 22.48 %. The short current density is 13.79 mA/cm^2.The open circuit voltage is 1.915 V. The fill factor is 85.17 %. The efficiency is 22.48 %.