Dissertations / Theses on the topic 'Capacitor storage'
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1
Ge, Yang. "Printed Charge Storage Capacitor." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-234123.
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In this thesis, new all-printed capacitors are developed for the applications of energy storage, filter, and resonant circuits by using new dielectric material and an advanced technology. The innovative devices provide satisficing electrical performances with high breakdown voltages and capacitance densities.
The main body of this thesis is divided in three parts. The first part is to introduce the fundamental background of printing technologies, electrical capacitors and printable materials. Among all the printing technologies, direct writing family is the most advantageous in the small-scale and fast production of printed electronics due to the properties of masterless processing, digital control, and print-on-demand. Both inkjet printing and ultrasonic fluid dispensing applied in this work are grouped into the direct writing family. A cross-linkable dielectric material poly(methyl methacrylate)84/(4-benzoylphenyl methacrylate)16 [P(MMA84/BPMA16)] exhibits the optimized chemical and mechanical stabilities in comparison with uncross-linked poly(methyl methacrylate) (PMMA). Poly(vinylidene fluoride-co-trifluoro ethylene) [P(VDF-TrFE)] exhibits a high dielectric constant of 16. The great advantages of both polymeric dielectrics make them ideal for printed electronics. The second part is devoted to the preparation of printed thin-film capacitors by providing four different layouts and architectures for multiple electronic applications. The printing setup, process setting and steps are summarized in detail.
The following part which is the major content of this thesis is divided into two aspects: in the first aspect, the intriguing new form of continuous solution dispensing technology, ultrasonic fluid dispensing, is demonstrated as an alternative printing technology for the commonly applied ones. In comparison with the widely-used inkjet printing, continuous solution dispensing is the most advantageous in thin-film capacitor processing with metal nanoparticle and polymer dielectric inks. It enables precise pattern transfers with low surface roughness, small feature size (as small as 5 μm), and accurate positioning (5 μm resolution).
Most importantly, problems due to discrete droplets and nozzle clogging in inkjet printing are avoided in continuous solution dispensing. All the inks applied for printed capacitors in this work are printed successfully with this innovating technology. Direct printing on demand and rapid switching among different inks are some other attributes of this printing technology that enable high throughput. The second aspect of this part is to characterize and evaluate the fabricated capacitors. The measured values include capacitor dimension, dielectric strength, capacitance density, energy density, charge/discharge behavior and so on.
In summary, this work provides not only the use of the advantageous materials P(MMA84/BPMA16) and P(VDF-TrFE) in high-performance capacitors, but also paves the way of developing thin-film capacitors with a new continuous solution dispensing technology which makes the low-cost and high-quality manufacture of printed devices possible.
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Wu, Ding. "Control of a super-capacitor based energy storage system." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/control-of-a-supercapacitor-based-energy-storage-system(e43378a8-22ec-442a-bc87-df4adb5fb3cb).html.
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The increasing use of electrical technologies within on-board (aircraft, road vehicle, train and ship) power systems is resulting in complex and highly dynamic networks in which energy storage devices have an important role to play, for example to resolve the instantaneous mismatch between load demand and power availability or to provide the flexibility to optimise overall performance. In this thesis, a multi-level controller for a super-capacitor based energy storage system (ESS) is designed, simulated, emulated and validated experimentally to show its effectiveness in smoothing load and managing state-of-charge of the energy storage system. This thesis first investigates the low level control of the dual-interleaved converter, particularly at light load where seven discontinuous conduction modes (DCMs) appear. A thorough analysis of these operating modes is given and validated by simulations and experiments. Based on the analysis, an inverse-model-based feed-forward current controller is implemented, offering a low level converter control interface which serves the high level supervisory controller within the energy storage system. Two supervisory control methods have been proposed in this thesis, both producing a super-capacitor current reference for the low level controller. The first supervisory control not only manages the energy within the ESS but also shields the primary power source from rapid load transients , which has been examined through an emulated ESS in the Intelligent Electrical Power Network Evaluation Facility (IEPNEF). A more advanced supervisory controller is then proposed which in addition to the benefits of the first control, regulates the rate-of-change in power that is drawn from the primary power source in the system. The proposed second control method is implemented within a real super-capacitor energy storage system in IEPNEF, with both simulation and experimental results successfully demonstrating and validating its operation.
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Zhou, Xin Zhang Qiming. "High energy/capacitance density poly(vinylidene fluoride) based polymers for energy storage capacitor applications." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-4578/index.html.
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Sehil, Khaled. "A super-capacitor based energy storage for quick variation in stand-alone PV systems." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16222.
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Photovoltaic (PV) system is one of the most prominent energy sources, producing electricity directly from sunlight. In additionally, it is easy to install and is supported financially by many governments as part of their strategy to reduce CO2 gas emissions, and to achieve their agreed set of reduction targets by 2020. In the meantime, researchers have been working on the PV system to make it more efficient, easy to maintain, reliable to use and cost effective. In the stand-alone PV system, a battery is required. This is due to the fluctuating nature of the output energy delivered by the PV arrays owing to the weather conditions and the unpredictable behaviour of uses with regard to the consumption of energy. During the hours of sunshine, the PV system is directly feeding the load and any surplus electrical energy is stored in the battery at a constant current. During the night, or during a period of low solar irradiation, the energy is supplied to the load from the battery. However, the stand-alone PV system is designed to provide an acceptable balance between reliability and cost, which is a major challenge to the designer owing to the approaches used to size the PV arrays and the battery bank. As a result, the unpredictable, quick daily changes on the PV output is not dependable. Moreover, battery performance, length of life and energy efficiency depends on the rate at which it is discharged. Therefore, it is essential to use other methods to deal with any quick variation in energy. In this thesis, a super capacitor is used to solve this problem, as it can deal with the fast-changing weather, or a rapid variation in the energy requirements of the customer. A critical evaluation with in-depth analysis of the placement and the implementation for the super-capacitor in the PV standalone system has been carried out. The results show, super-capacitor capacitance and the converter efficiency affect the delivered load energy. However, the bi-directional topology performs better than uni-directional under the same conditions. Finally, a further improvement of the system at component level, has been developed through an energy recovery snubber for the switching transition and achieved a recovery of energy for the resistive load, 94.44% for the turn on transition and 92.86% for the turn off transition. Moreover, for the inductive load, 78.33% and 97.33% of energy has been recovered for the turn on and for the turn off transition respectively.
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Alhuttaitawi, Saif. "Storage System for Harvested Energy in IoT Sensors." Thesis, Högskolan Kristianstad, Fakulteten för naturvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-18291.
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This work presents an energy system design for wireless sensor networks (WSNs) after applying our design the WSN should theoretically have an infinite lifetime. Energy harvesting sources can provide suitable energy for WSN nodes and reduce their dependence on battery. In this project, an efficient energy harvesting and storage system is proposed. By using (two supercapacitors and four DC/DC converters with step up /step down capabilities) all of them controlled by Microcontroller via switches to consider the best way to save energy to keep the WSN alive as long as possible. The usage of supercapacitors as an energy buffer to supply the sensor components (microcontroller and radio) with energy it needs to work. We could control the energy flow according to a specific voltage levels in supercapacitors to guaranty the full functionality for WSN with minimizing the loss of energy, and that’s leads to long time life for the wireless sensor node WSN. Another important thing we find in our experiment that is the inner leakage of the supercapacitor and how it has a critical effect on how long it can serve our system with energy. This paper contains on two theoretical sections (Part one and part two) which are based on literature reviews, and one experimental section (Part three) based on experimental building the prototype, coding and testing.
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Ge, Yang [Verfasser], Wolf-Joachim [Akademischer Betreuer] Fischer, Brigitte [Gutachter] Voit, and Karlheinz [Gutachter] Bock. "Printed Charge Storage Capacitor / Yang Ge ; Gutachter: Brigitte Voit, Karlheinz Bock ; Betreuer: Wolf-Joachim Fischer." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://d-nb.info/1156169623/34.
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Blechynden, Bruce. "Super-capacitor/lead acid battery hybrid energy storage suitable for remote area power supply (raps) systems." Thesis, Blechynden, Bruce (2010) Super-capacitor/lead acid battery hybrid energy storage suitable for remote area power supply (raps) systems. Other thesis, Murdoch University, 2010. https://researchrepository.murdoch.edu.au/id/eprint/4121/.
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This paper presents the results of simulations based on real load data collected from a RAPS system in the south west of Western Australia. The load data was collected at a rate of one sample per second to capture the transient changes. The data had features of a base load suited to lead-acid batteries and transient spikes in load suited to super-capacitors.
A model of a RAPS energy storage system including batteries and super-capacitors was built in Simulink. This model was designed to capture the major influences on battery life and performance: battery current, state of charge and battery temperature.
Simulations were run under standard conditions of no diesel generation (solar generation only), fixed ambient temperature (25°C), fixed total energy storage of 875Ah and equal hours of daylight and darkness.
An optimum super-capacitor size of 65Ah capacity was identified for the conditions of the simulation. Battery temperature was found to be dominated by ambient temperature and little improvement was achieved by including super-capacitors.
Battery life was improved by seven months from nine years and fourteen weeks to nine years and forty one weeks.
With the use of a 65Ah super-capacitor equivalent performance to the battery only base case can be achieved with a battery of 460Ah, approximately half the capacity of the existing batteries.
A 450Ah battery bank costs by $3520 less than the 875Ah battery bank used in the RAPS system that was monitored. A 65Ah super-capacitor costs between $115 500 and $147 500 indicating that a reduction in price in the order of forty times is necessary before super-capacitors could be justified in a battery super-capacitor hybrid energy store.
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Tong, Sheng. "Dielectric and Ferroelectric Properties of Lead Lanthanum Zirconate Titanate Thin Films for Capacitive Energy Storage." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352993943.
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Ku, Daniel C. (Daniel Chung-Ming) 1985. "Methodology, morphology, and optimization of carbon nanotube growth for improved energy storage in a double layer capacitor." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/63028.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 77-80).
The goal of this thesis is to optimize the growth of carbon nanotubes (CNTs) on a conducting substrate for use as an electrode to improve energy density in a double-layer capacitor. The focus has been on several areas, such as substrate material, growth conditions, catalyst variations, and thin-film deposition techniques in order to achieve growth of a high density, vertically-aligned carbon nanotube array suitable for use as an electrode. This thesis describes the methodology of modifying a significant number of parameters in order to achieve all of the targeted electrode specifications, with the exception of nanotube density. The successful growth of a CNT array on an aluminum foil substrate marks an important milestone for realizing a future commercial product.
by Daniel C. Ku.
S.M.
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Naderiallaf, Hadi <1986>. "Testing and modelling nanostructured insulation for capacitor and cables used for storage and delivery of electrical energy." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9898/1/Hadi%20Naderiallaf-PhD%20thesis-FINAL-Aug29-2021.pdf.
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The measurement of partial discharges (PD) is a commonly used tool to evaluate the healthiness of electrical insulation materials in high voltage systems such as HVDC cables. PD measurement is an important non-destructive test from predictive maintenance and asset management of high voltage equipment point of view which its activity can lead to premature failure. Modelling PD characteristics such as PD charge amplitude, PD repetition rate and partial discharge inception voltage (PDIV) is performed to provide an effective fundamental tool for the development of reliable quality control, commissioning tests and diagnostics procedures. In addition, a theoretical and analytical PD model can help in planning tests and evaluating the likelihood and meaningfulness of test data.
In this PhD thesis PD characteristics such as charge amplitude, repetition rate and PDIV are modelled base on PD RC equivalent circuit from AC to DC. The PD models were validated against experimental data obtained from laboratory testing on multilayer specimens at University of Bologna. The PDIV model under DC applying voltage was also validated after performing PD measurements on MV cable as a function of different temperatures (loads) in Technical University of Berlin. Then, the PD models were used to design a real HVDC insulation system to endure electrical and thermal stresses under operation using COMSOL Multiphysics simulations.
Finally, the effect of adding nano Silica with different functionalization to cable grade polymeric materials on electric and dielectric properties such as space charge, electrical conductivity, dielectric strength, and life test were investigated and evaluated experimentally.
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Fromille, Samuel S. IV. "Novel Concept for High Dielectric Constant Composite Electrolyte Dielectrics." Thesis, Monterey, California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/53408.
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Approved for public releaseThis research was part of an ongoing program studying the concept of multi-material dielectrics (MMD) with dielectric constants much higher than homogenous materials. MMD described in this study have dielectric constants six orders of magnitude greater than the best single materials. This is achieved by mixing conductive particles with an insulating surface layer into a composite matrix phase composed of high surface area ceramic powder and aqueous electrolyte. Specifically examined in this study was micron-scale nickel powder treated in hydrogen peroxide (H2O2) loaded into high surface area alumina powder and aqueous boric acid solution. This new class of dielectric, composite electrolyte dielectrics (CED), is employed in an electrostatic capacitor configuration and demonstrated dielectric constant of order 10 [raised to the 10th power] at approximately 1 Volt. Additionally, it is demonstrated that treated nickel can be loaded in high volume fractions in the CED configuration. Prior studies of composite capacitors indicated a general limitation due to shorting. This results from the onset of percolation due to excess loading of conductive phases. Insulated particles described herein are successfully loaded up to 40% by volume, far above typical percolation thresholds. Simple models are presented to explain results.
Lieutenant, United States Navy
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Wiacek, Kevin John. "SYNTHESIS AND ELECTRICAL PROPERTIES OF FLUORENYL POLYESTERS INCORPORATING DIAMOND FRAGMENTS." Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1183079024.
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Wade, Timothy Lawrence. "High power carbon based supercapacitors /." Connect to thesis, 2006. http://repository.unimelb.edu.au/10187/439.
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Energy storage devices are generally evaluated on two main requirements; power and energy. In supercapacitors these two performance criteria are altered by the capacitance, resistance and voltage. (For complete abstract open document)
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Bai, Yujie. "Evaluation of the Current-Fed CLLC DC/DC Converters for Battery and Super-Capacitor Based Energy Storage Systems Used in Electrified Transportation." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami157538965174651.
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SCALIA, ALBERTO. "New devices for energy harvesting and storage: integrated third generation photovoltaic solar cells and electrochemical double layer capacitors." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2724022.
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A worldwide conversion towards renewable energy sources has to be implemented in order to hopefully avoid the irreversible consequences of the global temperature increment caused by the greenhouse gases production.
In addition, the current need to benefit from electricity in every moment of daily life, mainly in case of limited access to the electric grid, is forcing the scientific community to an intensive effort towards the production of integrated energy harvesting and storage devices.
The topic of this PhD thesis is to investigate and propose innovative solutions for the integration of third generation photovoltaic (PV) cells and electrochemical double layer capacitors (EDLCs), the so-called photo-capacitors.
Different photo-capacitor structures have been studied and experimentally fabricated. At first, flexibility was explored, as it is a mandatory requirement to cover non-planar or bendable surfaces, which are more and more common in nowadays portable electronics. Easily scalable fabrication processes have been used for both the harvester and the storage units, employing photopolymer membranes as electrolytes and metallic grids as current collectors and electrodes substrates. For this configuration, the best overall conversion and storage efficiency ever reported for a flexible Dye sensitized solar cell (DSSC)-based photo-capacitor was demonstrated.
Subsequently, observing in the literature an evident lack in the exploitation of high voltage photo-capacitors, EDLC electrolytes with broad voltage windows have been examined. These electrolytes allowed to fabricate stable and reliable devices integrating the EDLC with a PV module and not only with a single solar cell, as normally is done. High voltage values, up to 2.5 V, have been obtained employing an ionic liquid electrolyte (Pyr14TFSI) or –alternatively- a solid state electrolyte (PEO-Pyr14TFSI) for storage section fabrication.
Moreover, novel electrolyte mixtures of organic solvents and ionic liquids with good physical and electrochemical properties have been employed with the aim to increase energy density and voltage with respect to commercial EDLCs.
Finally, a novel polymer-based platform has been suggested for the fabrication of an innovative “two-electrodes” self-powered device. The multifunctional polymeric layer, made of two poly(ethylene glycol)-based sections separated by a perfluorinated barrier, was obtained by oxygen-inhibited UV-light crosslinking procedure. For the energy harvesting section, one side of the polymeric layer was adapted to enable iodide/triiodide diffusion in a DSSC, while the other side empowered sodium/chloride ions diffusion and was used for on-board charge storage. The resulting photo-capacitor results in a planar architecture appreciably simplified with respect to other recently proposed solutions and is definitely more easily exploitable in low power electronics.
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Anoufa, Mickaël. "Nanocomposites et effet de dimensionnalité pour le stockage de l'énergie." Phd thesis, Ecole Centrale Paris, 2012. http://tel.archives-ouvertes.fr/tel-00832356.
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Dans le stockage d'énergie, les alternatives aux énergies fossiles sont peu nombreuses. Le stockage d'énergie dans un condensateur, permet d'atteindre de grande puissances électriques, mais pour une densité d'énergie trop faible. La présente thèse à pour objectif la compréhension des nano-céramiques ferroélectriques afin d'augmenter leur densité d'énergie et de se diriger ainsi vers un super-condensateur céramique. Nous avons développé dans un premier temps un modèle par champs effectif moyen du système core-shell. Une fois introduit dans l'énergie libre de Landau, ce modèle donne une idée de la densité d'énergie d'un système ferroélectrique donné. Les calculs - sur quelques pérovskites courantes - indiquent que la densité d'énergie reste relativement faible. Néanmoins nos calculs montrent que l'on peu optimiser le stockage d'énergie dans de telles céramiques en enrobant des grains de forme allongée comme des disques ou des fils. En outre, ce modèle phénoménologique permet d'expliquer de nombreuses mesures expérimentales sur les céramiques, y compris dans le cas ou s'ajoute de la conductivité et de la relaxation de Maxwell-Wagner. Nous nous sommes tournés par la suite vers une modélisation ab-initio : l'Hamiltonien effectif. La modélisation de nano-système core-shell de BaTiO3 a montré la présence d'un paramètre d'ordre particulier : le moment toroïdale. Ce paramètre d'ordre peut impliquer un comportement diélectrique différent. Introduit dans une description phénoménologique de type Landau, ce dernier est responsable de la disparition de la phase orthorhombique dans BaTiO3. La synthèse de nanoparticules de BaTiO3 de formes cubiques et homogènes, nous a permis de faire une série de mesure. Les mesures MET, RAMAN, RX, diélectriques sur les poudres et les céramiques, suggèrent la présences de transitions de phases générées par la présence d'un paramètre d'ordre similaire à celui observé dans modélisation ab-initio.
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Simsir, Bilge. "Analysis, Design, And Implementation Of A Two-switch Single Phase Electronic Line Voltage Regulator." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606043/index.pdf.
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Present day electrical equipment is rapidly becoming more and more sensitive to
power quality problems, especially voltage sags. Various voltage sag correction
devices are avaliable. This thesis analyzes a two-switch, single-phase electronic
voltage regulator for correcting voltage sags. The theory of this voltage regulator has
been investigated. An analytical method for sizing the energy storage capacitors has
been established. The voltage regulator has been modeled and its steady-state and
dynamic behavior has been studied by means of detailed computer simulations. A
220-V, 50-Hz, 1-kW rated regulator has been designed, simulated, and built. The
results on the performance of voltage regulator and conclusions are also given.
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Andres, Britta. "Paper-based Supercapacitors." Licentiate thesis, Mittuniversitetet, Avdelningen för naturvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-22410.
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The growing market of mobile electronic devices, renewable off-grid energy sources and electric vehicles requires high-performance energy storage devices. Rechargeable batteries are usually the first choice due to their high energy density. However, supercapacitors have a higher power density and longer life-time compared to batteries. For some applications supercapacitors are more suitable than batteries. They can also be used to complement batteries in order to extend a battery's life-time. The use of supercapacitors is, however, still limited due to their high costs. Most commercially available supercapacitors contain expensive electrolytes and costly electrode materials. In this thesis I will present the concept of cost efficient, paper-based supercapacitors. The idea is to produce supercapacitors with low-cost, green materials and inexpensive production processes. We show that supercapacitor electrodes can be produced by coating graphite on paper. Roll-to-roll techniques known from the paper industry can be employed to facilitate an economic large-scale production. We investigated the influence of paper on the supercapacitor's performance and discussed its role as passive component. Furthermore, we used chemically reduced graphite oxide (CRGO) and a CRGO-gold nanoparticle composite to produce electrodes for supercapacitors. The highest specific capacitance was achieved with the CRGO-gold nanoparticle electrodes. However, materials produced by chemical synthesis and intercalation of nanoparticles are too costly for a large-scale production of inexpensive supercapacitor electrodes. Therefore, we introduced the idea of producing graphene and similar nano-sized materials in a high-pressure homogenizer. Layered materials like graphite can be exfoliated when subjected to high shear forces. In order to form mechanical stable electrodes, binders need to be added. Nanofibrillated cellulose (NFC) can be used as binder to improve the mechanical stability of the porous electrodes. Furthermore, NFC can be prepared in a high-pressure homogenizer and we aim to produce both NFC and graphene simultaneously to obtain a NFC-graphene composite. The addition of 10% NFC in ratio to the amount of graphite, increased the supercapacitor's capacitance, enhanced the dispersion stability of homogenized graphite and improved the mechanical stability of graphite electrodes in both dry and wet conditions. Scanning electron microscope images of the electrode's cross section revealed that NFC changed the internal structure of graphite electrodes depending on the type of graphite used. Thus, we discussed the influence of NFC and the electrode structure on the capacitance of supercapacitors.
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El, Ghossein Nagham. "Étude et modélisation du fonctionnement et du vieillissement des « Lithium-Ion Capacitors » (LiC)." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1258/document.
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Le « Lithium-Ion Capacitor » (LiC) est un supercondensateur hybride dont les caractéristiques peuvent être placées entre un condensateur à double couche électrique (supercondensateur) et une batterie lithium-ion. Il possède des densités d’énergie et de puissance intermédiaires grâce à sa composition hybride à base d'une électrode positive en charbon actif identique à celle d’un supercondensateur et d'une électrode négative en carbone pré-lithié identique à celle d’une batterie lithium-ion. L'objectif de cette thèse est d'étudier le vieillissement des LiC industrialisés aussi bien dans le cadre d’un vieillissement en stockage (calendaire) qu’en utilisation (cyclage). Un de leur spécificité principale concerne l’évolution particulière de leur capacité en fonction de la tension à leurs bornes (C(V)). Le premier type de vieillissement qu’est le vieillissement calendaire permet de représenter le comportement des LiC lorsqu’ils sont stocker avant utilisation ou lorsqu’ils sont en veille. La dégradation de leurs paramètres liée au vieillissement, est alors essentiellement influencée par leur tension et la température. Des essais de vieillissement à trois tensions caractéristiques et deux températures différentes sont étudiés. L’évolution des impédances des cellules a été suivie tout au long du vieillissement afin d’identifier un modèle électrique de suivi du vieillissement dont les paramètres sont liés aux phénomènes électrochimiques. Par ces essais, la meilleure tension de stockage des LiC, permettant la prolongation de leur durée de vie a été mise en évidence. Par ailleurs, des mécanismes de vieillissement différents d’une tension caractéristique à l’autre sont révélés et soulignent la spécificité de fonctionnement des LiC. Ces résultats ont été confirmés par des analyses post-mortem. Le second type de vieillissement étudié est le vieillissement par cyclage qui prend en compte l'impact du courant sur la durée de vie des LiC. Le choix des profils de courant de cyclage a été effectué en considérant le principe de fonctionnement électrochimique des LiC. Les évolutions des impédances et des courbes C(V) des cellules sont comparées et interprétées. Les mécanismes de vieillissement prenant naissance lors du cyclage continu sont abordés. Ils dépendent de la fenêtre de potentiel sur laquelle les LiC fonctionnent pendant leur utilisation. La fenêtre de tension optimale qui assure une longue durée de vie des LiC est aussi mise en évidenceLithium-Ion Capacitors (LiCs) are the new emerging technology of hybrid supercapacitors that combines the advantages of conventional supercapacitors and lithium-ion batteries. They provide intermediate energy and power densities due to their hybrid composition based on a positive electrode made of activated carbon similar to that of supercapacitors and a negative electrode made of pre-lithiated carbon similar to that of lithium-ion batteries. The aim of this thesis is to study the aging of commercial LiCs using two accelerated aging procedures: calendar aging and cycle aging. One of their main particularities concerns the nonlinear capacitance evolution with respect to their voltage (C(V) curve). The first accelerated aging test is related to the calendar life of LiCs that represents their behavior independently of their usage. The degradation of their parameters due to aging is mainly affected by the voltage and the temperature only. These tests were applied to several cells at three different voltage values and two temperatures. The evolution of their impedances were followed during the whole aging period in order to identify an electrical model that can accurately describe the progress of aging and that possesses electrochemically meaningful parameters. The best voltage value that ensures the extension of the lifetime of LiCs was identified using the results of these tests. In addition, aging mechanisms that extremely depend on the applied voltage value were identified. They highlight the particularity of the functioning of LiCs. These results were confirmed using post-mortem analyses. The second accelerated aging test is the cycle aging that assesses the impact of the current on the life cycle of LiCs. The choice of current profiles was based on the electrochemical operating principle of LiCs. The evolution of the impedances and the C(V) curves of LiCs were compared and analyzed. Aging mechanisms produced during cycle aging were also evaluated. They depend on the voltage range in which the LiC operates. The optimal voltage window that guarantees a long lifetime of LiCs was highlighted
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Sallaz, Valentin. "Si-integrated capacitors for energy storage." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASF022.
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Avec la nécessité de toujours plus miniaturiser l’électronique, les composants doivent aujourd’hui être compatibles avec le processus d’empilement 3D. Murata Integrated Passive Solutions (MIS) propose alors la technologie « Passive Integrated Connecting Substrate » (PICS), consistant à intégrer sur silicium des composants passifs. L’objectif, dans notre cas, est la réalisation de micro-supercondensateurs (MSCs) à fortes densités d’énergie (~10 J.cm⁻³) pour répondre aux besoins de stockage d’énergie. Cette étude s’est articulée autour de quatre points clés : (1) l’implémentation d’un électrolyte solide inorganique en couches minces pour MSCs, le LiPON, (2) l’optimisation des interfaces et des modes de stockage (surfacique ou volumique), (3) le développement d’un LiPON ultra fin déposé par Atomic Layer Deposition (ALD), enfin (4) l’augmentation de la surface spécifique du MSC à partir de procédés de nano structuration. L’ensemble du travail repose sur une étude systématique, couplant résultats électriques et électrochimiques à des analyses physico-chimiques poussées. L’électrolyte LiPON, lorsqu’intégré en configuration Métal – Isolant - Métal (MIM), a démontré un mode de stockage de type double couche électroniques (conformément aux EDLCs), avec de bonnes performances en termes de cinétique et d’énergie stockée. Cette dernière a pu être améliorée en implémentant une couche d’oxyde, du TiO₂, impliquant de nouveaux modes de stockage. La relation matériau/performance ainsi déterminée a servi de base pour le développement de MSCs ultra minces. La faisabilité d’un dépôt de LiPON par ALD électriquement fonctionnel a pu être démontrée, et son intégration dans des structures 3D à fort ratio d’aspect a permis de donner de premiers résultats encourageants quant aux performances cibléesWith the ever-increasing need for miniaturized electronics, components must be compatible with the 3D integration. Murata Integrated Passive Solutions (MIS) offers the Passive Integrated Connecting Substrate (PICS) technology, which integrates passive components on silicon. The objective of the present work is to fabricate high energy density micro-supercapacitors (MSCs) (~ 10 J.cm⁻³) to meet the energy storage needs. This study focused on four key points: (1) implementation of a thin film inorganic solid-state electrolyte for MSCs, LiPON, (2) interfaces and storage modes (surface or bulk) optimization, (3) development of ultrathin LiPON layers deposited by Atomic Layer Deposition (ALD), and (4) MSC specific surface area enhancement via nano structuring processes. The whole work is based on a systematic study, combining electrical and electrochemical results with advanced physical and chemical analysis. When integrated in a Metal – Insulator - Metal (MIM) configuration, the LiPON electrolyte exhibited an electronic double layer storage mode (like EDLCs), with good performance in terms of kinetics and stored energy. The latter was further improved by implementing an oxide layer, TiO₂, implying new storage modes. This material/performance relationship served as a basis for the development of ultra-thin MSCs. The feasibility of an electrically functional ALD LiPON deposition was demonstrated, and its integration into high aspect ratio 3D structures gave first encouraging results regarding the targeted performance
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Eriksson, Robin. "Heat storages in Swedish district heating systems : An analysis of the installed thermal energy storage capacity." Thesis, Högskolan i Halmstad, Energivetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-31143.
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District heating is the most common source of heating in Sweden and has played a crucial part in the country’s substantial reductions of carbon dioxide emissions. This recycling technology is ideal in order to use thermal energy as efficiently as possible and makes the goals set for a sustainable future more achievable. The future potential of this technology is therefore huge. Today, a lot of the district heating systems have installed heat storages in order to improve the systems reliability and performance. These heat storages have the potential to be utilized even further in the future by acting as a balancing power for the power grid. However, there is currently no data available regarding the storage capacity available in the district heating systems. This thesis therefore seeks to quantify the installed storage capacity in Swedish district heating systems. The data gathered regarding this can then be utilized in research regarding potential future applications of heat storages, such as balancing the power grid. All collected data regarding heat storage capacity has also been analyzed in an effort to find any correlations between the relative storage capacity and the size, energy sources, customer prices and operational costs of each investigated system. This analysis has concluded that most of the district heating systems in Sweden have installed storage capacity and that it is more commonly used in larger systems. It is also concluded that most of the installed storage capacity is used to counteract daily heat load variations. The heat storages influence district heating systems by reducing their operational costs as well.Den vanligaste formen av uppvärmning i Sverige är fjärrvärme. Sverige har minskat landets utsläpp av koldioxid kraftigt det senaste årtiondet och fjärrvärmen har bidragit stort till denna bedrift. Denna teknologi är ideal när det gäller att återvinna samt använda värme så effektivt som möjligt. Potentialen för den teknik i framtiden är därför stor. Många fjärrvärmesystem har idag värmelager i systemet för att öka dess effektivitet och pålitlighet. Dessa värmelager kan potentiellt utnyttjas ännu mer i framtiden genom att aggera som balanskraft för elnätet. Det finns dock ingen data tillgänglig gällande lagerkapaciteten som finns tillgänglig i fjärrvärmesystemen i dagsläget. Syftet med detta examensarbete är därför att kvantifiera och analysera den installerade lagerkapaciteten i Sveriges fjärrvärmesystem. Den insamlade datan kan sedan användas i studier för framtida applikationer för värmelager, så som att agera som balanskraft för elnätet. All insamlad informationen om värmelagernas kapacitet har även analyserats för att hitta samband mellan den relativa lagerkapaciteten för varje fjärrvärmesystem och dess storlek, energikällor, kundpriser samt driftkostnader. Slutsatser som har dragits från denna analys är att de flesta fjärrvämesystemen i Sverige har värmelager installerade, samt att värmelager är vanligare i större fjärrvärmesystem. De flesta värmelagren används till att balansera daliga variationer i värmelasten och värmelager sänker även driftkostnaderna för fjärrvärmesystemen.
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Onay, Aytun. "Hydrogen Storage Capacity Of Nanosystems: Molecular." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609636/index.pdf.
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In recent decades, tremendous efforts have been made to obtain high hydrogen storage capacity in a stable configuration. In the literature there are plenty of experimental works investigating different materials for hydrogen storage and their storage values. In the first part of this thesis the available literature data have been collected and tabulated. In addition to the literature survey the hydrogen storage capacity of carbon nanotubes and carbon nanotubes doped with boron nitride (CBN nanotubes) with different chirality have been investigated by performing quantum chemical methods at semiempirical and DFT levels of calculations. It has been found that boron nitrite doping increases the hydrogen storage capacity of carbon nanotubes. Single wall carbon nanotubes (SWNT) can be thought as formed by warping a single graphitic layer into a cylindrical object. SWNTs attract much attention because they have unique electronic properties,
very strong structure and high elastic moduli. The systems under study include the structures C(4,4), H2@C(4,4), C(7,0), C(4,0), and the BN doped C(4,4), H2@C(4,4), 2H2@C(4,4), C(7,0), H2@C(7,0), 2H2@C(7,0). Also, we have investigated adsorption and desorption of hydrogen molecules on BN doped coronene models by means of theoretical calculations.
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Prodjinonto, Vincent. "Contribution à l'économie d'énergie dans le bâtiment : mesure de capacité de stockage dynamique d'une paroi." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14449/document.
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L’économie d’énergie dans le bâtiment est devenue une question préoccupante d’envergure internationale. Le secteur du bâtiment en effet, est l’un des plus énergétivores avec par exemple plus de 43% du total d’énergie produite en France, mais aussi l’un des plus polluants avec environs, 23% des émissions de gaz à effet de serre. Avec l’accroissement des ménages, et la demande par conséquent d’énergie, les problèmes ci-dessus évoqués vont décupler et devenir rapidement ingérables les années à venir, si aucune mesure n’est prise. Ainsi, pour faire face à la situation, plusieurs stratégies sont mises en œuvre aux fins de réaliser l’économie d’énergie dans le bâtiment. Il y a le volet prédiction d’énergie qui oeuvre pour l’énergie juste heure après heure ; le volet recherche et élimination de ponts thermiques, afin de réduire au minimum les déperditions d’énergie représentant environ 30% de la consommation d’énergie ; et le volet conservation d’énergie dans les parois de bâtiment pour sa réutilisation future. Notre thèse s’est penchée sur les deux derniers volets en proposant différentes méthodes de CND et des traitements appropriés permettant la mise en évidence de défauts dans les structures de bâtiment. Des approches d’estimation de matrice de transfert ont été aussi abordées, pour permettre de prévoir le comportement thermique du bâtiment soumis à une sollicitation quelconque. La grande contribution de cette thèse concerne la mise au point d’une technique de mesure de capacité de stockage in-situ. Elle est importante, car il existe quantité de logiciels proposant la composition des structures d’un bâtiment pour une capacité de stockage d’énergie donnée. Mais il n’existe aucune méthode permettant de confirmer ou d’infirmer les résultats issus de calculs artificiels. Cette thèse apporte une solution à cette situation en proposant une méthode simple, sans encombrement, facile à mettre en œuvre et offrant un résultat satisfaisantEnergy saving in buildings has become a major international issue. Indeed, the building sector is one the most energy consuming sectors, for instance in France it consumes more than 43% of the total produced energy, and also it is one of the most polluter with around 23% of the green house gas emissions. As more and more households appear, the energy demand will increase and the above mentioned problems will be ten times more sever making them unmanageable in the upcoming years if no measure is taken. Thus, to face this situation, many strategies have been setup in order to achieve some energy saving in buildings. Among these strategies we find the energy prediction part which deals with hour by hour right energy; the research and elimination part of thermal bridges which its main objective is to reduce as much as possible the energy losses representing around 30% of the energy consumption; and the energy conservation part in wall buildings for future recycling. Our thesis focuses on the last two parts by proposing different methods of CND as well as appropriate survey treatments which allow to highlight structural failure in buildings. Transfer matrix estimation approaches have been used to predict the thermal behavior for a building that is being put under any kind of stress.The main contribution of this thesis concerns the developing of an in-situ storage capacity measuring technique. This is important since there are many softwares proposing the structural composition of a building for a given amount of energy. Nevertheless, there isn’t any method available for confirming or invalidating the results coming from artificial calculations. This thesis brings a solution to this situation by proposing a simple method, with no obstacles, easy to setup and with satisfactory results
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Chan, Siu-wo. "Design, control and application of battery-ultracapacitor hybrid systems." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38816660.
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Erninger, Anders, and Moulham Alsakati. "Storage Capacity Evaluation of Autoassociative Neural Network Models." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297684.
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utoassociative memory models have been an at-tractive area for researchers lately. Their potential for modellingsome aspects of the human memory put them in the spotlight fordeeper research. In this project, we study the effects of making anautoassociative memory network capture some functional aspectsof the human memory. This by applying some modifications to aHopfield network with Hebbian learning rule. The modificationsused in this project are implementing Oja’s rule on the learningrule as well as creating a sparse network instead of an all-to-allconnected one. We then evaluate the storage capacity for differentautoassociative memory networks based on the Hopfield networkmodel and the Hebbian learning rule. We found that Oja’s rulesignificantly improved the network ability to recall newly learnedpatterns as well as slightly improved the ability to retainingold memories. Sparsifying the network led to decreasing theoverall storage capacity depending on the amount of connectionsremoved.Autoassociativa neurala nätverk har varit ett attraktivt område för forskare den senaste tiden. Deras potential att modellera några aspekter av det mänskliga minnet placerade dem i rampljuset för djupare forskning. I detta projekt studerar vi effekterna av att modifiera ett autoassociativ minnesnätverk. Vi utvärderar lagringskapaciteten för olika autoassociativa minnesmodeller baserat på Hopfield- nätverksmodellen och Hebbians inlärningsregel. Modifieringarna som studeras i detta projekt är implementering av Ojas princip på inlärningsregeln och skapnandet av ett glest nätverk istället för ett nätverk med en alla-till-alla anslutning. Vi fann att Ojas princip förbättrade nätverkets förmåga att återkalla nyligen inlärda mönster och förbättrade förmågan upprätthålla gamla minnen. Det glesa nätverket ledde till att den totala lagringskapaciteten minskade med hänsyn till mängden av antal borttagna anslutningar.
Kandidatexjobb i elektroteknik 2020, KTH, Stockholm
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Venkataraman, Anuradha. "Pseudocapacitors for Energy Storage." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2486.
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Fluctuation in the demand for electrical power and the intermittent nature of the supply of energy from renewable sources like solar and wind have made the need for energy storage a dire necessity. Current storage technologies like batteries and supercapacitors fall short either in terms of power output or in their ability to store sufficient energy. Pseudocapacitors combine features of both and offer an alternative to stabilize the power supply. They possess high rates of charge and discharge and are capable of storing much more energy in comparison to a supercapacitor. In the quest for solutions that are economical and feasible, we have investigated Prussian Blue in aqueous electrolytes for its use as a pseudocapacitor. Two different active materials based on Prussian Blue were prepared; one that has just Prussian Blue and the other that contains a mixture of Prussian Blue and carbon nanotubes (CNTs). Four electrolytes differing in the valence of the cation were employed for the study. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrodes. Our experiments have shown specific capacitances of Prussian Blue electrodes in the range of 140-720 F/g and that of Prussian Blue-CNT electrodes in the range of ~52 F/g. The remarkable capacity of charge storage in Prussian Blue electrodes is attributed to its electrochemical activity ensuring surface redox and its tunnel-like structure allowing ease of entry and exit for ions like Potassium. Simple methods of synthesis have yielded specific capacitances of the order of hundreds of Farads per gram showing that Prussian Blue has promise as an electrode material for applications needing high rates of charge-discharge.
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Hlongwa, Ntuthuko Wonderboy. "Thermochemical Storage and Lithium Ion Capacitors Efficiency of Manganese-Graphene Framework." University of the Western Cape, 2018. http://hdl.handle.net/11394/6458.
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Philosophiae Doctor - PhD (Chemistry)Lithium ion capacitors are new and promising class of energy storage devices formed from a combination of lithium-ion battery electrode materials with those of supercapacitors. They exhibit better electrochemical properties in terms of energy and power densities than the above mentioned storage systems. In this work, lithium manganese oxide spinel (LiMn2O4; LMO) and lithium manganese phosphate (LiMnPO4; LMP) as well as their respective nickel-doped graphenised derivatives (G-LMNO and G-LMNP) were synthesized and each cathode material used to fabricate lithium ion capacitors in an electrochemical assembly that utilised activated carbon (AC) as the negative electrode and lithium sulphate electrolyte in a two-electrode system. The synthetic protocol for the preparation of the materials followed a simple solvothermal route with subsequent calcination at 500 - 800 ?C. The morphological, structural and electrochemical properties of the as prepared materials were thoroughly investigated through various characterisation techniques involving High resolution scanning electron microscopy (HRSEM), High resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), Small-angle X-ray scattering (SAXS), Electrochemical impedance spectroscopy (EIS), Cyclic voltammetry (CV) and Galvanostatic charge/discharge.
2021-12-31
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Magogodi, Steven Mothibakgomo. "Hydrogen storage capacity of the Ti-Pd multilayer systems." University of the Western Cape, 2020. http://hdl.handle.net/11394/7711.
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>Magister Scientiae - MScHydrogen has high energy density and it is regarded as the future energy carrier. Hydrogen can be stored as a gas in high-pressure cylinders, as a liquid in cryogenic tanks and as a solid in metal hydrides. The storage of hydrogen in gas and liquid form has many limitations. Light metal hydrides show high energy density and are a promising and more practical mode of hydrogen storage. In particular, titanium and its alloys are promising metal hydrides for hydrogen storage due to their high affinity to hydrogen. The aim of this study is to investigate the effect of thermal annealing on hydrogen storage capacity of Ti-Pd multilayer systems. Ti-Pd multilayer films were prepared on CP-Ti (commercial pure Ti) and Ti6Al4V substrates using an electron beam evaporator equipped with a thickness monitor. The sequential deposition of layers Pd(50nm)/Ti(25nm)/Pd(50nm) was done at a constant deposition rate of 0.6 Å/s. The first batch of samples were thermally annealed at 550 °C in vacuum for two hours, the second batch of samples were annealed at 550 oC under H2(15%)/Ar(85%) gas mixture for two hours and the third series of samples was annealed under pure H2 gas at 550 oC for one hour. SEM showed relatively homogeneous and smooth topography of surfaces in as-deposited samples, while a rough textured surface was observed in both samples annealed under vacuum and under H2/Ar gas mixture. The samples annealed under pure H2 gas did not show any sign of crystallites grow but instead a relatively smooth surface with sign of etching. XRD revealed structural transformation as evidenced by the presence of PdTi2 phase in samples annealed under vacuum; in samples annealed under the gas mixture Pd2Ti was noted in addition to TiH2 and TiO2. While the TiH2 phase is an indication of hydrogen absorption, the TiPd2 phase suggests intermixing of the deposited layers and the presence of TiO2 is evidence of oxidation. The samples annealed under pure H2 gas showed only TiH2 with no trace of structural transformation. RBS confirmed the intermixing of layers in the samples annealed under vacuum and H2(15%)/Ar(85%) gas mixture, while samples annealed under pure H2 gas did not show any intermixing of layers. ERDA revealed an average H content of ~ 3.5 at.% in CP-Ti and ~6.2 at.% in Ti6Al4V for samples annealed under H2(15%)/Ar(85%) gas mixture. We recorded an hydrogen content of ~19.5 at.% in CP-Ti annealed under pure H2 while ~25.5 at.% was found in Ti6Al4V annealed under the same conditions. When the thickness of the Pd catalyst layers was increased to 100 nm (i.e. Pd (100 nm)/Ti (25 nm)/Pd (100 nm)), only ~ 12.5 at.% and 11.2 at. % hydrogen content was recorded in samples prepared on CP-Ti and Ti6Al4V alloy respectively, both annealed under pure hydrogen for one hour as above.
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Koen, Damien Joseph. "Structural Capacity of Light Gauge Steel Storage Rack Uprights." Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/3880.
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This report investigates the down-aisle buckling load capacity of steel storage rack uprights. The effects of discrete torsional restraints provided by the frame bracing in the cross-aisle direction is considered in this report. Since current theoretical methods used to predict the buckling capacity of rack uprights appear to be over-conservative and complex, this research may provide engineers an alternative method of design using detailed finite element analysis. In this study, the results from experimental testing of upright frames with K-bracing are compared to finite element predictions of displacements and maximum axial loads. The finite element analysis is then used to determine the buckling loads on braced and un-braced uprights of various lengths. The upright capacities can then be compared with standard design methods which generally do not accurately take into account the torsional resistance that the cross-aisle frame bracing provides to the upright. The information contained in this report would be beneficial to engineers or manufacturers who are involved in the design of rack uprights or other discretely braced complex light gauge steel members subject to axial loads.
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Koen, Damien Joseph. "Structural Capacity of Light Gauge Steel Storage Rack Uprights." University of Sydney, 2008. http://hdl.handle.net/2123/3880.
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Master of Engineering (Research)This report investigates the down-aisle buckling load capacity of steel storage rack uprights. The effects of discrete torsional restraints provided by the frame bracing in the cross-aisle direction is considered in this report. Since current theoretical methods used to predict the buckling capacity of rack uprights appear to be over-conservative and complex, this research may provide engineers an alternative method of design using detailed finite element analysis. In this study, the results from experimental testing of upright frames with K-bracing are compared to finite element predictions of displacements and maximum axial loads. The finite element analysis is then used to determine the buckling loads on braced and un-braced uprights of various lengths. The upright capacities can then be compared with standard design methods which generally do not accurately take into account the torsional resistance that the cross-aisle frame bracing provides to the upright. The information contained in this report would be beneficial to engineers or manufacturers who are involved in the design of rack uprights or other discretely braced complex light gauge steel members subject to axial loads.
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Zhang, Yuanci. "Performance and ageing quantification of electrochemical energy storage elements for aeronautical usage." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0029/document.
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Dans un contexte de progression du stockage d’énergie sous forme électrochimique dans les transports, notamment dans l’aéronautique, les problématiques de performance, de fiabilité, de sureté de fonctionnement et de durée de vie du stockeur sont essentielles pour utilisateurs. Cette thèse se focalise ces voltes pour l’avion plus électrique. Les technologies étudiées correspondent à des éléments commerciaux de dernière génération de type Lithium-ion (NMC/graphite+SiO, NCA/graphite, LFP/graphite, NMC/LTO), Lithium-Soufre (Li-S), supercondensateur et hybride (LiC). Une première partie de ce manuscrit s’attache à la quantification des performances des différents éléments dans l’environnement aéronautique [-20°C, 55°C] et pour l’usage aéronautique. Un modèle comportemental de type électro-thermique est développé et validé. La seconde partie est consacrée à la quantification du vieillissement des différents éléments. Les résultats de vieillissement calendaire et en cyclage actif sont présentés ainsi que ceux des tests abusifs. Une méthode d’estimation de l’état de santé (SOH) des éléments basés sur l’analyse de la capacité incrémentale (ICA) est proposée. Enfin, l’évaluation de la robustesse des éléments de stockage lors de tests de vieillissement accéléré avec un profil spécifique à l’usage aéronautique est proposé. Les modèles de vieillissement et la méthode d'estimation de SOH proposés précédemment sont utilisés ici pour évaluer l'impact de la température sur la vitesse de dégradation et pour estimer le SOH des cellules vieillies à l’aide de ce profil aéronautiqueIn the context of progress in the electrochemical energy storage systems in the transport field, especially in the aeronautics, the issues of performance, reliability, safety and robustness of these elements are essential for users. This thesis is focused on these issues for the more electric aircraft. The technologies studied correspond to the latest generation commercial elements of Lithium-ion batteries (NMC/ graphite + SiO, NCA/graphite, LFP/graphite, NMC/LTO), Lithium-Sulfur (Li-S), Supercapacitor and Lithium-ion capacitors. The first part of this manuscript is dedicated to the performance quantification of the different electrochemical energy storage elements in aeronautical environment [-20°C, 55°C] and usage. An efficient and accurate electro-thermal model is developed and validated. The second part is devoted to the calendar and power cycling ageings as well as to the presentation of abuse testing results. A State Of Health (SOH) estimation based on incremental capacity analysis method is proposed. Finally, the robustness of the storage elements during accelerated ageing tests with a specific profile for the aeronautical usage is evaluated. The ageing models and SOH estimation methods proposed in the previous sections are used here to evaluate the impact of temperature on the degradation rate and to estimate the SOH of the cells with this aeronautical profile
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Baake, Robert Stefan Mr. "A FLYBACK INVERTER TOPOLOGY WITHOUT ELECTROLYTIC INPUT CAPACITORS AS ENERGY STORAGE ELEMENT." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1032.
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ABSTRACT
A Flyback Inverter Topology without Electrolytic Input Capacitors as Energy Storage Element
Robert Baake
In today’s PV inverters, the high input capacitance, necessary for the energy storage during the slow 60Hz cycle is provided by bulky electrolytic capacitors. Liquid electrolyte stored in the capacitor is quickly evaporated due to above rating temperatures, leading to a rise in ESR (equivalent series resistance). The resulting elevated heat dissipation reduces efficiency and accelerates degradation, possibly leading to eventual failure of the inverter. The challenge is to replace these electrolytic capacitors with a different energy storage element. This thesis proposes a new inverter using a Flyback transformer to eliminate the use of electrolytic capacitors as energy storage. A 35W inverter prototype was designed and built to demonstrate the operation of the proposed inverter. Results show that the inverter is able to provide a square-wave AC output, without large electrolytic input capacitance, while meeting several design specifications.
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Wang, Zhiyu. "Effects of Impurities on CO2 Geological Storage." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32061.
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This project studied the physical and chemical effects of typical impurities on CO2 storage using both experimental approaches and theoretical simulation. Results show that the presence of typical non-condensable impurities from oxyfuel combustion such as N2, O2, and Ar resulted in lower density than pure CO2, leading to decreased CO2 storage capacity and increased buoyancy in saline aquifers. In contrast, inclusion of condensable SO2 in CO2 resulted in higher density than pure CO2 and therefore increased storage capacity. These impurities also had a significant impact on the phase behaviours of CO2, which is important to CO2 transportation. Different effects on rock chemistry were detected with experimental systems containing pure CO2, CO2 with SO2, or CO2 with SO2 and O2 under conditions simulating that in a potential storage site. An equation was proposed to predict the effects of the rock chemistry on the porosity of rocks.
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Mucelini, Johnatan. "Estudo ab initio da adsorção de átomos de zircônio sobre superfícies de óxido de cério: Zrn/CeO2(111)." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/75/75134/tde-23102018-161515/.
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Catalisadores baseados em óxidos de cério (CeOx, 3/2≤ x ≤ 2) como suporte são utilizados em várias reações de alto interesse econômico, por exemplo as reações de catalizadores de três-vias. Sabe-se que é possível melhorar as propriedade catalíticas da céria, através da mistura com óxido de zircônio e com a adição de partículas metálicas na superfície do material. Entretanto, a deposição de átomos de Zr sobre CeO2(111) é pouco explorada apesar de já ter sido utilizada para a síntese de nanopartículas de Ag de tamanho controlado. Uma das particularidades dos sistemas Zr/CeO2(111) é formar ilhas altura entre 1,5 e 3,0 Å sobre a superfície da céria que são sugeridas na literatura com camadas de Zr-O e O-Zr-O. Entretanto, a natureza e magnitudes das interações entre Zr e CeO2(111) ainda não são totalmente conhecidas, bem como as modificações causadas pelo Zr na superfície de CeO2 e os mecanismos que controlam a oxidação do Zr e a formação de ZrO2 na superfície. Visando entender as interações Zr/CeO2(111) e a formação de ZrO2 sobre CeO2(111), realizou-se um estudo teórico da adsorção de n (1 ≤n ≤ 4) adatomos de Zr sobre CeO2(111), e da formação de ZrO2 sobre CeO2(111). As análises de carga indicam transferências de carga do adatomos de Zr para a superfície e mudança no estado de oxidação das espécies. Os Zr se oxidam á Zr4+ e interagem com O2- da superfície, onde quatro cátions Ce4+ se reduzem á Ce3+. Analises energéticas indicam que o processo é muito estabilizante, mais de 10 eV por Zr. Com o aumento da quantidade n de adatomos de Zr na superfície, observa-se 4 × n reduções de Ce4+ e migrações de O2- de dentro da superfície para próximo dos Zr4+, formando agregados de ZrO2 sobre a superfície. A migração de O se deve a dois fatores, a interação dos O2- com Zr4+ no agregado é mais estável do que a interação dos O2- com Ce3+ dentro da superfície, e a migração de O diminuir a tensão causada pelo maior raio do Ce3+ em relação ao Ce4+. Em adição, foi encontrado uma tendência de estabilidade para os Zr4+ migrarem para sítios Ce dentro da superfície, devido a maior quantidade de coordenações Zr-O e a redução da tensão criada pelos Ce3+.Cerium oxides (CeOx, 3/2≤ x ≤ 2) based catalysts are employed in several reactions with high economic interest, such as the reaction in three-way-catalysts. It is well know that is possible to improve the ceria catalytic properties, by mixing with zirconium oxide and adding metallic particles over the material surface. Meanwhile, the deposition of Zr atoms over CeO2(111) is little explored although it has already been used for synthesis Ag nanoparticles of controlled size. One of the particularities of the Zr/CeO2(111) systems is to form islands of height between 1,5 and 3,0 Å on the surface of the ceria, which are suggested in the literature to be Zr-O and O-Zr-O layers. However, the nature and magnitudes of interactions between Zr and CeO2 surface are little know, as well as the CeO2 modifications induced by Zr and the mechanisms for Zr oxidation and ZrO2 formation over the surface. Aiming to understand the Zr-CeO2(111) interactions and the ZrO2 formation over the CeO2(111), this mastering project perform a theoretical study of n (1 ≤ n ≤ 4) Zr adatoms absorption over CeO2(111), and the ZrO2 formation over CeO2(111). The charge analysis indicated charge transfer from Zr adatons to the surface together with change in species oxidation state. The Zr oxidize to Zr4+ and interact with surface O2- , where four Ce4+ cations reduce to Ce3+. Energetic analysis pointed out that the process is very stabilizing, more than 10 eV per Zr adatom. With the increase of quantity n of Zr adatoms over the surface, it is observer 4 × n Ce4+ reductions and O2- migrations from inside surface to close the Zr4+, forming ZrO2 aggregates over the surface. The O migration occurs because of two reasons, the O2- interaction with Zr4+ in the agregate is more stabilizer than the interaction of O2- with Ce3+ inside the surface, and the O migration decrease the strain produced bue to the radius of Ce3+ being greater than the Ce4+ radius. In addition, was found a stability trend for Zr4+ to migrate to inside surface Ce sites, due of the more Zr-O coordinations and release of the strain induced by Ce3+.
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Dai, Tinglong. "Inventory management in the face of a limited storage capacity /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?IELM%202006%20DAI.
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Rivera, Ramirez Hector David. "Flood control reservoir operations for conditions of limited storage capacity." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1464.
Full textAbstract:
The main objective of this research is to devise a risk-based methodology for
developing emergency operation schedules (EOS). EOS are decision tools that provide
guidance to reservoir operators in charge of making real-time release decisions during
major flood events. A computer program named REOS was created to perform the
computations to develop risk-based EOS. The computational algorithm in REOS is
divided in three major components: (1) synthetic streamflow generation, (2) mass
balance computations, and (3) frequency analysis. The methodology computes the
required releases to limit storage to the capacity available based on the probabilistic
properties of future flows, conditional to current streamflow conditions. The final
product is a series of alternative risk-based EOS in which releases, specified as a
function of reservoir storage level, current and past inflows, and time of year, are
associated with a certain risk of failing to attain the emergency operations objectives.
The assumption is that once emergency operations are triggered by a flood event, the risk
associated with a particular EOS reflects the probability of exceeding a pre-established
critical storage level given that the same EOS is followed throughout the event. This
provides reservoir operators with a mechanism for evaluating the tradeoffs and potential
consequences of release decisions.
The methodology was applied and tested using the Addicks and Barker Reservoir
system in Houston, TX as a case study. Upstream flooding is also a major concern for
these reservoirs. Modifications to the current emergency policies that would allow
emergency releases based on the probability of upstream flooding are evaluated. Riskbased
EOS were tested through a series of flood control simulations. The simulations
were performed using the HEC-ResSim reservoir simulation model. Rainfall data
recorded from Tropical Storm Allison was transposed over the Addicks and Barker
watersheds to compute hypothetical hydrographs using HEC-HMS. Repeated runs of
the HEC-ResSim model were made using different flooding and residual storage
scenarios to compare regulation of the floods under alternative operating policies. An
alternative application of the risk-based EOS in which their associated risk was used to
help quantify the actual probability of upstream flooding in Addicks and Barker was also
presented.
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Beheshti, Zavareh Elham. "Calcium-decorated boron-doped graphene for high-capacity hydrogen storage." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/24218.
Full textAbstract:
Hydrogen has been viewed as a clean synthetic energy carrier that could replace fossil fuels, especially for transport applications. One bottleneck in developing a hydrogen economy is to find feasible and safe storage materials that can store hydrogen with high gravimetric and volumetric densities at ambient conditions. The U.S. depart ment of energy has set a system target of 6 wt.% hydrogen storage density by 2010 and 9 wt.% by 2015, which has not been met yet. In this thesis, hydrogen adsorption and storage in calcium-decorated boron-doped graphene is studied by ab initio calculations using density functional theory (DFT).
We first consider pure graphene coated with calcium atoms on both sides, supposing that metal atoms are dispersed uniformly on the surface with a calcium coverage of 25%. We find that up to four hydrogen molecules can bind to a Ca atom, which results in a storage capacity of 8.32 wt.%. Then, we address the issue of metal adsorbate clustering. Our calculations show that Ca clustering takes place on pristine graphene because of the small binding energy of Ca to graphene. One way to enhance the metal adsorption strength on the graphene plane is to dope graphene with acceptors such as boron atoms. We show that upon boron doping with a concentration of 12 at.%, the clustering problem could be prevented and the resulting gravimetric capacity is 8.38 wt.% hydrogen.
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Bowles, Richard. "Investigating the storage capacity of a network with cell assemblies." Thesis, Middlesex University, 2006. http://eprints.mdx.ac.uk/9773/.
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Cell assemblies are co-operating groups of neurons believed to exist in the brain. Their existence was proposed by the neuropsychologist D.O. Hebb who also formulated a mechanism by which they could form, now known as Hebbian learning. Evidence for the existence of Hebbian learning and cell assemblies in the brain is accumulating as investigation tools improve. Researchers have also simulated cell assemblies as neural networks in computers. This thesis describes simulations of networks of cell assemblies. The feasibility of simulated cell assemblies that possess all the predicted properties of biological cell assemblies is established. Cell assemblies can be coupled together with weighted connections to form hierarchies in which a group of basic assemblies, termed primitives are connected in such a way that they form a compound cell assembly. The component assemblies of these hierarchies can be ignited independently, i.e. they are activated due to signals being passed entirely within the network, but if a sufficient number of them. are activated, they co-operate to ignite the remaining primitives in the compound assembly. Various experiments are described in which networks of simulated cell assemblies are subject to external activation involving cells in those assemblies being stimulated artificially to a high level. These cells then fire, i.e. produce a spike of activity analogous to the spiking of biological neurons, and in this way pass their activity to other cells. Connections are established, by learning in some experiments and set artificially in others, between cells within primitives and in different ones, and these connections allow activity to pass from one primitive to another. In this way, activating one or more primitives may cause others to ignite. Experiments are described in which spontaneous activation of cells aids recruitment of uncommitted cells to a neighbouring assembly. The strong relationship between cell assemblies and Hopfield nets is described. A network of simulated cells can support different numbers of assemblies depending on the complexity of those assemblies. Assemblies are classified in terms of how many primitives are present in each compound assembly and the minimum number needed to complete it. A 2-3 assembly contains 3 primitives, any 2 of which will complete it. A network of N cells can hold on the order of N 2-3 assemblies, and an architecture is proposed that contains O(N2) 3-4 assemblies. Experiments are described that show the number of connections emanating from each cell must be scaled up linearly as the number of primitives in any network .increases in order to maintain the same mean number of connections between each primitive. Restricting each cell to a maximum number of connections leads, to severe loss of performance as the size of the network increases. It is shown that the architecture can be duplicated with Hopfield nets, but that there are severe restrictions on the carrying capacity of either a hierarchy of cell assemblies or a Hopfield net storing 3-4 patterns, and that the promise of N2 patterns is largely illusory. When the number of connections from each cell is fixed as the number of primitives is increased, only O(N) cell assemblies can be stored.
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Ding, Yate. "Investigation of high capacity heat energy storage for building applications." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/30955/.
Full textAbstract:
The problems of excessive consumption of fossil resources, oil shortages and greenhouse gas emissions are becoming increasingly severe. Research and development work on new methods of thermal energy storage are imminently required. To effectively store seasonal renewable energy, a novel high capacity heat storage system has been designed and evaluated/validated through laboratory experiments and numerical simulations in this research. The system is driven by direct flow evacuated tube solar collector with enhanced PCM tank and intends to be applied in residential and commercial buildings. Theoretical and experimental approaches and numerical analysis have been employed in this study. Firstly, phase change materials (PCM) with specific heat density, melting point, melting and solidifying time have been investigated. This type of PCMs can maintain a considerable high internal temperature of environment chamber in a frozen ambient temperature. Numerical modelling has been conducted on a passive house (Nottingham H.O.U.S.E) to study whether proposed thermochemical materials can cover relative heating load and be power by solar panel in terms of roof size. Meanwhile, PCMs have been used to give a long duration for temperature-controlled chamber in laboratory, and thermochemical materials have been utilized in closed pumping pipe system for cooling and heating purpose. Secondly, characteristic experiments have been conducted on a modified solar collector working with an enhanced PCM tank that is integrated with a fan coil heat exchanger. The results show that light radiation of tungsten lamps (as a solar simulator) has approximately 70% efficiency to equate to solar radiation under the same Pyranometer reading value. At the same time, the solar system can supply over 50°C heating energy and the PCM tank within it can supply higher output temperature with longer duration than water tank. The efficiency of the whole solar collector heating system is over 50% as a heat absorption chamber in sunny days, while only approximately 10% under mostly cloudy weather. Lastly, proposed thermochemical materials (silica gel, calcium chloride, zeolite 13x, vermiculite and activated carbon) have been evaluated on designed thermochemical absorption chamber to supply fresh high temperature air for space heating. The results show that zeolite holds the highest reacted temperature (over 58°C) and vermiculite has really fast absorbing hydration duration, less than half hour. Silica gel possesses the biggest water absorbing capacity and vermiculite has a worse result. A comparison between experimental and numerical modelling results has been revealed. Considering the complexity of processes in cooling and heating system, the agreement of simulation and experimentation is satisfactory, thus the lumped numerical model is acceptable and significant for investigation of this scaled seasonal high capacity heat storage system. A full size seasonal heat storage system with a nominal heating capacity of 3kW has been proposed and illustrated in economic and environmental issues section. The results from net present value (NPV) and internal rate of return (IRR) sensitivity analysis both shows it is greatly attractive to develop this novel system for application in both household and commercial buildings in consideration of its about 9 years payback period, 20 years life span and zero gas (C02) emissions. An intelligent transpired solar collector system is also introduced and illustrated as future work.
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Chan, Siu-wo, and 陳兆和. "Design, control and application of battery-ultracapacitor hybrid systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38816660.
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Melzer, Michael. "Entwicklung von Werkzeugen zur automatisierten Traktionsspeicherdimensionierung auf dieselelektrisch angetriebenen Schienenfahrzeugen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-144328.
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Diese Arbeit befasst sich mit der Implementierung eines Energiespeichersystems in ein dieselelektrisches Schienenfahrzeug. Ziel der Arbeit ist es mit einem automatisierten Ansatz die besten Parameter für das Energiespeichersystem zu finden. Um die geeignetsten Parameter zu bestimmen, wurde eine Optimierung basierend auf genetischen Algorithmen verwendet. Neben der Charakteristik des Energiespeichersystems wird auch dessen Betriebsstrategie untersucht und optimiert. Der Fahrstil genau wie die Leistung des Dieselmotors werden ebenfalls variiert, um die Ergebnisse der Optimierung mit und ohne Energiespeichersystem zu vergleichenThis work deals with an implementation of an energy storage system in a diesel electric driven rail vehicle. The aim of this work is an automatic approach to find the best parameters for an energy storage system. To find the best fitting parameters an optimization based on genetic algorithms is used. Beside the characteristics of the energy storage system as well the strategy to operate it is investigated and optimized. The driving style as well as the power of the internal combustion engine are varied in order to compare the solution of the optimization with and without energy storage systems
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Dall'Agnese, Yohan. "Study of early transition metal carbides for energy storage applications." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30025/document.
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La demande urgente d'innovations dans le domaine du stockage de l'énergie est liée au développement récent de la production d'énergie renouvelable ainsi qu'à la diversification des produits électroniques portables qui consomment de plus en plus d'énergie. Il existe plusieurs technologies pour le stockage et la conversion électrochimique de l'énergie, les plus notables étant les batteries aux ions lithium, les piles à combustible et les supercondensateurs. Ces systèmes sont utilisés de façon complémentaire des uns aux autres dans des applications différentes. Par exemple, les batteries sont plus facilement transportables que les piles à combustible et ont de bonne densité d'énergie alors que les supercondensateurs ont des densités de puissance plus élevés et une meilleure durée de vie. L'objectif principal de ces travaux est d'étudier les performances électrochimiques d'une nouvelle famille de matériaux bidimensionnel appelée MXène, en vue de proposer de nouvelles solutions pour le stockage de l'énergie. Pour y arriver, plusieurs directions ont été explorées. Dans un premier temps, la thèse se concentre sur les supercondensateurs dans des électrolytes aqueux et aux effets des groupes de surface. La seconde partie se concentre sur les systèmes de batterie et de capacités à ions sodium. Une cellule complète comportant une anode en carbone et une cathode de MXène a été développées. La dernière partie de la thèse présente l'étude des MXènes pour les supercondensateur en milieu organique. Une attention particulière est apportée à l'étude du mécanisme d'intercalation des ions entre les feuillets de MXène. Différentes techniques de caractérisations ont été utilisées, en particulier la voltampérométrie cyclique, le cyclage galvanostatique, la spectroscopie d'impédance, la microscopie électronique et la diffraction des rayons XAn increase in energy and power densities is needed to match the growing energy storage demands linked with the development of renewable energy production and portable electronics. Several energy storage technologies exist including lithium ion batteries, sodium ion batteries, fuel cells and electrochemical capacitors. These systems are complementary to each other. For example, electrochemical capacitors (ECs) can deliver high power densities whereas batteries are used for high energy densities applications. The first objective of this work is to investigate the electrochemical performances of a new family of 2-D material called MXene and propose new solutions to tackle the energy storage concern. To achieve this goal, several directions have been explored. The first part of the research focuses on MXene behavior as electrode material for electrochemical capacitors in aqueous electrolytes. The next part starts with sodium-ion batteries, and a new hybrid system of sodium ion capacitor is proposed. The last part is the study of MXene electrodes for supercapacitors is organic electrolytes. The energy storage mechanisms are thoroughly investigated. Different characterization techniques were used in this work, such as cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, scanning electron microscopy and X-ray diffraction
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Leyva, García Sarai. "Advanced nanostructured carbon materials for electrochemical energy storage devices: supercapacitors and micro-capacitors." Doctoral thesis, Universidad de Alicante, 2016. http://hdl.handle.net/10045/65694.
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Shiva, Reddy Sai Giridhar. "Dielectric and ferroelectric nanomaterials combined with carbon nanotubes for capacitive energy storage." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648108.
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Jayasekara, Manathum Nadeeshani Pushpamala. "Intelligent control of PV co-located storage for feeder capacity optimization." Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/1415.
Full textAbstract:
Battery energy storage is identified as a strong enabler and a core element of the next generation grid. However, at present the widespread deployment of storage is constrained by the concerns that surround the techno-economic viability. This thesis addresses this issue through optimal integration of storage to improve the efficiency of the electricity grid. A holistic approach to optimal integration includes the development of methodologies for optimal siting, sizing and dispatch coordination of storage.
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Zorzi, Luca <1987>. "Managing storage capacity and production set point for photovoltaic production plants." Master's Degree Thesis, Università Ca' Foscari Venezia, 2012. http://hdl.handle.net/10579/1961.
Full textAbstract:
The objective of this thesis is to realize an intelligent application that manages
renewable energy production plants with the capability of storing energy into
batteries, and in particular for the FIAMM Green Energy Island plant. Factors
to be taken into account are mainly: energy market prices, energy consumption
forecasting, energy production forecasting, state of charge of the batteries and
signals of the smart grid manager. At each interval the data is updated and
the model is veried, making the necessary modications to the power curve in
case of variations with respect to the forecasting maked in a previous time. The
application interacts with a SCADA system using a database.
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Mullendore, Marina Anita Jacqueline. "Assessment of the Geological Storage Potential of Carbon Dioxide in the Mid-Atlantic Seaboard: Focus on the Outer Continental Shelf of North Carolina." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100687.
Full textAbstract:
In an effort to mitigate carbon dioxide (CO2) emissions in the atmosphere, the Southeast Offshore Storage Resource Assessment (SOSRA) project has for objective to identify geological targets for CO2 storage in two main areas: the eastern part of the Gulf of Mexico and the Atlantic Ocean subsurface. SOSRA's second objective is to estimate the geological targets' capacity to store up to 30 million metric tons of CO2 each year with an error margin of ±30%. As part of this project, the research presented here focuses on the outer continental shelf of North Carolina and its potential for the deployment of large-scale offshore carbon storage in the near future. To identify geological targets, workflow followed typical early oil and gas exploration protocols: collecting existing datasets, selecting the most applicable datasets for reservoir exploration, and interpreting datasets to build a comprehensive regional geological framework of the subsurface of the outer continental shelf. The geomodel obtained can then be used to conduct static volumetric calculations estimating the storage capacity of each identified target. Numerous uncertainties regarding the geomodel were attributed to the variable coverage and quality of the geological and geophysical data. To address these uncertainties and quantify their potential impact on the storage capacity estimations, dynamic volumetric calculations (reservoir simulations) were conducted. Results have shown that, in this area, both Upper and Lower Cretaceous Formations have the potential to store large amounts of CO2 (in the gigatons range). However, sensitivity analysis highlighted the need to collect more data to refine the geomodel and thereby reduce the uncertainties related to the presence, dimensions and characteristics of potential reservoirs and seals. Reducing these uncertainties could lead to more accurate storage capacity estimations. Adequate injection strategies could then be developed based on robust knowledge of this area, thus increasing the probability of success for carbon capture and storage (CCS) offshore projects in North Carolina's outer continental shelf.Doctor of Philosophy
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Bhattcharya, Mayukh. "Degradation in lead zirconate titanate thin film capacitors for non-volatile memory applications /." This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-09052009-040636/.
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Ramadan, Mohamed Elamin Awad. "A novel high capacity space efficient heat storage system for domestic application." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/53239/.
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Solar energy assisted heat pump (SAHP) and Direct Expansion Solar Assisted Heat Pump (DX-SAHP) systems are among the promising means of reducing the consumption of fossil fuels for heat production in residential building applications. The research in this thesis introduces a novel system that integrates solar energy, THS storage, and DX-SAHP. The objective is to develop an efficient heating system for existing homes in the cold climatic region which is sustainable and acts as an alternative to the conventional high energy loss domestic water and space heating systems. One of the prospective techniques of producing and storing of thermal energy is the application of thermochemical materials. Storage of heat in salt hydrates provides an efficient and compact way of storing energy. Hence, the properties of salt hydrates that determine the storage capacity are being investigated. An experimental test has undertaken to assess the effect of integrating the new design of thermochemical storage materials with a solar-assisted multifunctional heat pump system. This research presents a novel design that involves the integration of DX-SAMHP and a hot water tank with a thermochemical sorption jacket. Investigations have been carried out to determine a suitable temperature range for household heating systems. Expanded Vermiculite (host matrix) and CaCl2 (hygroscopic salt) have been used as composite material in an adsorbent reaction jacket for a domestic water tank. The new design has a total volume of 20 kg of V/CaCl2, which can store the thermal energy with a complete reaction. The results show the high capability of the tested materials to enhance the domestic heating system performance when applied in cold regions. The feasibility of the designed system for residential space and water heating is also demonstrated. The maximum energy density obtained through the discharging process is 565 kJ/kg. It is also revealed that the coupling of thermochemical heat storage and heat pump increases the thermal production capacity by 1.166 kWh during the discharging process.
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Haffor, Al-Said A. "Carbon dioxide storage capacity of endurance and sprint-trained athletes in exercise /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487259125221279.
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