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

Paper based Supercapacitors for vehicle KERS-application

Blomquist, Nicklas January 2012 (has links)
High mobility has been a standard in the modern world for decades. This has resulted in high energy consumption, diminishing fossil energy reserves and rising levels of greenhouse gases. By recovering the energy lost in deceleration of vehicles the total energy consumption can be decreased and exhaust emissions reduced. This can be done with a kinetic energy recovery system (KERS) that converts kinetic energy to electric energy during deceleration, which then can be used for acceleration. KERS requires an electrical storage device with high power density, due to the high power levels generated at heavy braking. Batteries does not generally meet these requirements, especially in the cost-effective point of view, but different types of capacitors can be used to obtain a cheap and effective system. To get such an energy storage device small, lightweight and inexpensive while the technology is sustainable requires avoidance of rare metals and hazardous materials. In this master thesis energy and power levels for KERS has been modelled, based on standardized measurements techniques and small paper-based supercapacitors have been built and tested in order to model size, weight and price for a full-scale energy storage device to a KERS-application. The models showed that energy consumption in urban traffic could be reduced with 18% and with an electrode material for the energy storage device with a capacitance of about 1500 F/m2 a reasonable size and weight is obtained. To reach these values of capacitance in paper-based supercapacitors further testing is required on area and layer dependence and for different electrodes.
2

Li-ion titanate technology for SLI battery applications in commercial vehicles / Li-jon titanat teknologi för SLI-batteritillämpning i kommersiella fordon

Vasilevich, Liliya January 2021 (has links)
Litiumjon-batterier har blivit väldigt populära för tillämpning i fordon. Den här teknologin har fler olika kemier att erbjuda som kontinuerligt förbättras. Litium-titanat-oxid-batterier använder (LTO) LTO som anod och erbjuder långt cyklingsliv samt minskar risk för SEI-bildning och litiumplätering.  Det här examensarbetet siktade på att undersöka om LTO-batterier kan användas som startbatterier i kommersiella fordon. Metodologin inkluderade två motorstart försök med en kommersiell 12s1p LTO-modul, laddnings/urladdningtester med en kommersiell LTO-cell med nominell spänning 2.3V samt överurladdningstester med byggda pouchceller. Materialet för pouchceller extraherades från en kommersiell LTO-cell och sedan studerades med SEM-EDX före och efter överurladdningstesterna. Resultatet visade att LTO-batterier kan användas som startbatterier i en diesel V8 motor även vid 39%SoC. Dessutom visade simuleringar att LTO-batterier kan användas inom Kinetic Energy Recovery System (KERS) tillämpning och behålla 60% SoC efter 500 laddning/urladdnings cykler. Resultaten från både KERS och motorstarterna visade att LTO är en lovande kandidat för ersättning av blybatterier. Laddnings/urladdnings tester visade att en kommersiell 12s1p LTO modul kan maximalt uppnå 73%SoC när den laddas med fordon-liknande strömmar. Däremot var SoC oberoende av laddningsström. Överurladdningstester med pouchceller visade att det är relativt ofarligt att urladda LTO 0.4V under spänningsgränsen utan stora ökningar i impedans eller stor kapacitetsförlust. Största förluster kopplades till åldring av NMC-baserade positiva elektroden. / Lithium ion batteries have become quite popular in vehicle applications in the past few decades. This technology offers multiple chemistries to choose from, that are continuously studied and improved. Lithium-titanate-oxide (LTO) batteries use LTO material as an anode, providing long cycling life, as well as essentially eliminating risk for SEI formation and lithium plating.  This Master thesis project aimed to investigate how well LTO-based lithium-ion batteries can perform in Start Ignition Lighting (SLI) application in commercial vehicles. The methodology included two engine crank tests with a commercial 12s1p LTO module, charge/discharge tests on a commercial LTO cell with nominal voltage 2.3V, as well as overdischarge cycling tests on assembled pouch cells. The materials for the pouch cells were extracted from a commercial LTO cell and later analysed with SEM-EDX before and after overdischarge tests. The results demonstrated that LTO-based Li-ion batteries can be successfully start a diesel V8 engine even at 39% SoC. Furthermore, when simulating an urban vehicle with an implemented Kinetic Energy Recovery System (KERS) application, a commercial cell LTO cell achieved and retained around 60\%SoC throughout 500 charge/discharge cycles. Combined results from KERS and engine start tests imply that LTO is a strong candidate for replacing lead-acid in these applications. Charge/discharge tests showed that commercial 12s1p LTO cell can maximum reach around 73%SoC when charged in a vehicle-like way. However, this maximum SoC limit was more or less independent of applied charging current. Furthermore, electrochemical overdischarge tests on the pouch cells demonstrated that it is relatively safe to overdischarge the cell 0.4V below the specified safety limit without significant rise in impedance or capacity fade. Major performance losses were attributed to the aging of the NMC-based positive electrode.
3

ALTERNATE POWER AND ENERGY STORAGE/REUSE FOR DRILLING RIGS: REDUCED COST AND LOWER EMISSIONS PROVIDE LOWER FOOTPRINT FOR DRILLING OPERATIONS

Verma, Ankit 2009 May 1900 (has links)
Diesel engines operating the rig pose the problems of low efficiency and large amount of emissions. In addition the rig power requirements vary a lot with time and ongoing operation. Therefore it is in the best interest of operators to research on alternate drilling energy sources which can make entire drilling process economic and environmentally friendly. One of the major ways to reduce the footprint of drilling operations is to provide more efficient power sources for drilling operations. There are various sources of alternate energy storage/reuse. A quantitative comparison of physical size and economics shows that rigs powered by the electrical grid can provide lower cost operations, emit fewer emissions, are quieter, and have a smaller surface footprint than conventional diesel powered drilling. This thesis describes a study to evaluate the feasibility of adopting technology to reduce the size of the power generating equipment on drilling rigs and to provide ?peak shaving? energy through the new energy generating and energy storage devices such as flywheels. An energy audit was conducted on a new generation light weight Huisman LOC 250 rig drilling in South Texas to gather comprehensive time stamped drilling data. A study of emissions while drilling operation was also conducted during the audit. The data was analyzed using MATLAB and compared to a theoretical energy audit. The study showed that it is possible to remove peaks of rig power requirement by a flywheel kinetic energy recovery and storage (KERS) system and that linking to the electrical grid would supply sufficient power to operate the rig normally. Both the link to the grid and the KERS system would fit within a standard ISO container. A cost benefit analysis of the containerized system to transfer grid power to a rig, coupled with the KERS indicated that such a design had the potential to save more than $10,000 per week of drilling operations with significantly lower emissions, quieter operation, and smaller size well pad.
4

Analys och utveckling av drivsystemoberoende energiåtervinning

Gilani, Ramin January 2011 (has links)
Limitations in energy recovery technology require extended research for development of existing and alternative solutions. This thesis project has treated valuing pneumatic drivetrain independent energy recovery system as a potential solution. The prototype built during this project uses a piston compressor to transform kinetic energy into compressed air. The compressed air was then stored in two air tanks and transformed into kinetic energy with an air motor on demand. The prototype was built on a rig using a high power electrical engine to simulate energy input from the wheels during braking. The air motor was then used to rotate a Volvo S40 engine simulating energy output to the wheels. To further illustrate how the technology can be implemented in vehicles and to emphasize the variety of pneumatic energy recovery solutions a 3D CAD model was designed and other components was reflected. Such as using a screw compressor instead of piston and also using the compressor as a motor reducing the number of components optimizing the system. The system storing the kinetic energy does not mean that the vehicle can manage without an ordinary brake system. The regenerative braking effect rapidly reduces at lower speeds; therefore friction brake is still required in order to bring the vehicle to a complete halt.Analyses of strength of strained components acknowledge that limited energy recovery is possible without redimensioning the driveshaft´s. The limitation is regulated by the original dimension for engine load, with subject to the CV joint. Optimum positioning of the compressor due to the limited space in a modern vehicle is behind the gearbox in conjunction with the gearbox outgoing pinion for short energy transportation.Electrical energy recovery system is the solution with the highest potential on the market today but electrical vehicles covers just a fraction of the vehicle industry doe to technical and infrastructural limitations. Drivetrain independent pneumatic, hydraulic or mechanical energy recovery systems lay the foundation of a common ground for all vehicles and other waste energy machinery to use one energy recovery technology. The market research indicates that this type of technology is up-to-the-minute. / <p>Validerat; 20110106 (anonymous)</p>

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