4,687 research outputs found

    Optimized energy management strategies and sizing of hybrid storage systems for transport applications

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    205 p. El contenido del capítulo 4, sección 4.3 está sujeto a confidencialidad.Esta tesis doctoral aborda la temática acerca del óptimo dimensionamiento y operación de sistemashíbridos de almacenamiento de energía (HESS), combinando baterías y supercapacitores, con el objetivode ser integrados en vehículos para movilidad pública en entornos urbanos. Por una parte, se propone unainnovadora estrategia energética, basada en lógica difusa, para gestionar la división de la demanda depotencia entre las fuentes de energía disponibles a bordo del vehículo. La estrategia adaptativa que sepropone evalúa la información energética actual y futura (estimada) para adaptar, de una formaoptimizada y eficiente, la operación del sistema con el objetivo de mejorar el aprovechamiento de laenergía almacenada en los recursos a bordo del vehículo.Por otro lado, se ha propuesto una metodología para la co-optimización de la estrategia de gestión ydimensionamiento del HESS. Esta metodología de optimización evalúa tanto técnica comoeconómicamente las posibles soluciones mediante un problema multi-objetivo basado en algoritmosgenéticos. Para determinar el costo de reemplazo del HESS han sido aplicados modelo de envejecimientoy estimación de vida y se ha considerado la vida útil del vehículo.Con el objetivo de validar la propuesta de esta tesis doctoral, dos casos de estudio relevantes en latransportación pública han sido seleccionados: Tranvía Eléctrico Híbrido y Autobús Eléctrico Híbrido

    Trends and Hybridization Factor for Heavy-Duty Working Vehicles

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    Reducing the environmental impact of ground vehicles is one of the most important issues in modern society. Construction and agricultural vehicles contribute to pollution due to their huge power trains, which consume a large amount of petrol and produce many exhaust emissions. In this study, several recently proposed hybrid electric architectures of heavy-duty working vehicles are presented and described. Producers have recently shown considerable attention to similar research, which, however, are still at the initial stages of development. In addition, despite having some similarities with the automotive field, the working machine sector has technical features that require specific studies and the development of specific solutions. In this work, the advantages and disadvantages of hybrid electric solutions are pointed out, focusing on the greater electromechanical complexity of the machines and their components. A specific hybridization factor for working vehicles is introduced, taking into account both the driving and the loading requirements in order to classify and compare the different hybrid solutions

    Advances on Smart Cities and Smart Buildings

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    Modern cities are facing the challenge of combining competitiveness at the global city scale and sustainable urban development to become smart cities. A smart city is a high-tech, intensive and advanced city that connects people, information, and city elements using new technologies in order to create a sustainable, greener city; competitive and innovative commerce; and an increased quality of life. This Special Issue collects the recent advancements in smart cities and covers different topics and aspects

    Replacing combustion engines with hydrogen fuel cells to power mining haul trucks: challenges and opportunities

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    With the proven advantage of higher energy density in hydrogen fuel cells over batteries, there is potential to apply fuel cells to power mining haul trucks. This study aims to evaluate the technical and economic feasibility of hydrogen fuel cell electric mine trucks as an alternative to current mine haul trucks. Specifically, the project: (1) developed an economic framework for evaluating the integration of renewable energy powered haul trucks into mining; and (2) applied vehicle drivetrain and energy simulation in Matlab/Simulink to elucidate the challenges and opportunities of incorporating hydrogen fuel cell technology into the current form factors of mine haul trucks. First, the study uses an optimization model to characterize the impact of production, market and policy parameters on a mining firm’s decision of what types of trucks (with or without renewable technology) to deploy to minimize its overall costs, including costs associated with greenhouse gas emissions. Second, is an investigation of the significant technical challenges and opportunities associated with integrating hydrogen fuel cells in mining haul trucks using the vehicle drivetrain model and simulation experiments. The results show that even with green energy government incentives and levies for greenhouse gas emission, the cost of operating green energy trucks needs to be competitive to ensure they minimize a mining firm’s cost. However, to utilize a hydrogen fuel cell truck in the mine, a new vehicle frame is likely required to support the integration of the technology. This would require financial and technical investments by original equipment manufacturers and mining firms to make the transition --Abstract, page iii

    Energy storage systems to exploit regenerative braking in DC railway systems: Different approaches to improve efficiency of modern high-speed trains

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    The growing attention to environmental sustainability of transport systems made necessary to investigate the possibility of energy optimization even in sectors typically characterised by an already high level of sustainability, as in particular the railway system. One of the most promising opportunity is the optimization of the braking energy recovery, which has been already considered in tramway systems, while it is traditionally overlooked for high-speed railway systems. In this research work, the authors have developed two simulation models able to reproduce the behavior of high-speed trains when entering in a railway node, and to analyze the impact of regenerative braking in DC railway systems, including usage of energy storage systems. These models, developed respectively in the Matlab-Simscape environment and in the open source Modelica language, have been experimentally validated considering an Italian high-speed train. After validation, the authors have performed a feasibility analysis considering the use of stationary and on-board storage systems, also by taking into account capital costs of the investment and annual energy saving, to evaluate cost-effectiveness of the different solutions. The analysis has shown the possibility to improve the efficiency of high-speed railway systems, by improving braking energy recovery through the installation of such storage systems

    Report of the LSPI/NASA Workshop on Lunar Base Methodology Development

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    Groundwork was laid for computer models which will assist in the design of a manned lunar base. The models, herein described, will provide the following functions for the successful conclusion of that task: strategic planning; sensitivity analyses; impact analyses; and documentation. Topics addressed include: upper level model description; interrelationship matrix; user community; model features; model descriptions; system implementation; model management; and plans for future action

    Study and Implementation of Compact Modeling Techniques for the Energy Analysis and Optimization of Complex Systems

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    L'abstract è presente nell'allegato / the abstract is in the attachmen

    A Hydrogen Hybrid Powertrain for the Union-Pearson Railway

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    Canadian legislation attempts to regulate particle emissions released from the rail transportation sector. Assessment of the impact of rolling stock is the key to perform such regulations. Different strategies have been proposed to evaluate the health risks of mobile emission sources. Popular methods in measuring health assessment of rolling stock were reviewed in this study. Hydrail was proposed as an alternative option helping Canadian legislation to regulate emission generated from this mode of transportation. The feasibility of developing Hydrail technology is investigated. As a case study, the drive cycle of the DMUs working on the Air-Rail link’s tracks of Great Toronto Area (GTA) was extracted. A theoretical model was implemented to estimate the duty cycle of the train as it was not possible to access the DMU’s throttle data. According to the duty cycle estimator subsystem, the annual emission released from the track is calculated. To assess the health risk on people, 32 places which are located near the track were collected, and the locations were extracted using Google Earth. These places include hospitals, schools, and social community centers. The concentration of three types of pollutants was locally approximated in the 32 places, using Gaussian air dispersion modeling method. To implement the model, commercial software, AERMOD, was used. To contemplate the health effect of the trains, the estimated pollution concentrations were compared with the air quality standards. The Hydrail was introduced as an alternative technology to reduce the health impact of the rail sector. The benefits and drawbacks of the technology were introduced in detail. Finally, a hydrogen powertrain is designed in this study with respect to the estimated duty demand. This should be considered as the first subsystem of an end-to-end Hydrail design platform for this 25 Km long rail route. A frequency-based power management scenario was applied to the developed powertrain to control the power flow between energy sources. A sensitivity analysis was performed to approximate the system dynamics. The proposed power management scenario is capable to optimally keep the system working in its optimal working region whenever it will become integrated with a real-time high-level global optimization subsystem
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