Análisis de viabilidad para almacenamiento de Co2 en la estructura geológica Villameriel (Palencia)

El presente proyecto lleva a cabo un análisis de la viabilidad de la estructura geológica Villameriel, situada en la provincia de Palencia, para el almacenamiento geológico profundo de CO2. Las dos medidas determinadas para su análisis serán la determinación de la cantidad de CO2 que se puede inyectar en la formación y el comportamiento del mismo en su interior durante los próximos 100 años. Para calcular estas medidas utilizamos la simulación numérica, a través de dos programas de SCHLUMBERGER. El primero, PETREL, diseñando un modelo estático que escenifique las propiedades del medio geológico lo más real posible, llamado modelo estático. El segundo, ECLIPSE300, que simula el comportamiento del fluido según entra en la formación y a lo largo de todo el período de estudio. Como conclusión final llevaremos a cabo un estudio económico que analice el potencial que tiene este proyecto para llevarse a cabo en la sociedad en la que nos encontramos ahora mismo ABSTRACT This project analyzes the viability of Villameriel geological structure, which is situated in Palencia, Spain. There will be two measures to probe it. The first will be to calculate how much amount of CO2 can be stored in this structure, and second will be to see how the CO2 behaves inside the first 100 years. In order to obtain the answers from these questions, Schlumberger programs are used specifically PETREL and ECLIPSE300. This programs work with numerical methods and they simulate a static model and a dynamic model. Static model is created in order to build a geological model with the same properties than in the real life. Dynamic model works to obtain the maximum amount of CO2 that it can be introduced inside storage formation and to know how CO2 will move inside the first 100 years. At the end, an economic study will be done with the objective to know if it would cost money, if there would be profits or no.

Advanced background modeling with RGB-D sensors through classifiers combination and inter-frame foreground prediction

An innovative background modeling technique that is able to accurately segment foreground regions in RGB-D imagery (RGB plus depth) has been presented in this paper. The technique is based on a Bayesian framework that efficiently fuses different sources of information to segment the foreground. In particular, the final segmentation is obtained by considering a prediction of the foreground regions, carried out by a novel Bayesian Network with a depth-based dynamic model, and, by considering two independent depth and color-based mixture of Gaussians background models. The efficient Bayesian combination of all these data reduces the noise and uncertainties introduced by the color and depth features and the corresponding models. As a result, more compact segmentations, and refined foreground object silhouettes are obtained. Experimental results with different databases suggest that the proposed technique outperforms existing state-of-the-art algorithms.

Caracterización de parámetros petrofísicos relacionados con la capacidad de almacenamiento de CO2 en el acuífero salino profundo de Hontomín (Burgos)

La conciencia de la crisis de la modernidad -que comienza ya a finales del siglo XIX- ha cobrado más experiencia debido al conocimiento de los límites del desarrollo económico, ya que como parecía razonable pensar, también los recursos naturales son finitos. En 1972, el Club de Roma analizó las distintas opciones disponibles para conseguir armonizar el desarrollo sostenible y las limitaciones medioambientales. Fue en 1987 cuando la Comisión Mundial para el Medio Ambiente y el Desarrollo de la ONU definía por primera vez el concepto de desarrollo sostenible. Definición que posteriormente fue incorporada en todos los programas de la ONU y sirvió de eje, por ejemplo, a la Cumbre de la Tierra celebrada en Río de Janeiro en 1992. Parece evidente que satisfacer la demanda energética, fundamentalmente desde la Revolución Industrial en el s XIX, trajo consigo un creciente uso de los combustibles fósiles, con la consiguiente emisión de los gases de efecto invernadero (GEI) y el aumento de la temperatura global media terrestre. Esta temperatura se incrementó en los últimos cien años en una media de 0.74ºC. La mayor parte del incremento observado desde la mitad del siglo XX en esta temperatura media se debe, con una probabilidad de al menos el 90%, al aumento observado en los GEI antropogénicos, siendo uno de ellos el CO2 que proviene de la transformación del carbono de los combustibles fósiles durante su combustión. Ante el creciente uso de los combustibles fósiles, los proyectos CAC, proyectos de captura, transporte y almacenamiento, se presentan como una contribución al desarrollo sostenible ya que se trata de una tecnología que permite mitigar el cambio climático. Para valorar si la tecnología CAC es sostenible, habrá que comprobar si existe o no capacidad para almacenar el CO2 en una cantidad mayor a la de producción y durante el tiempo necesario que impone la evolución de la concentración de CO2 en la atmósfera para mantenerla por debajo de las 450ppmv (concentración de CO2 que propone el Panel Intergubernamental para el Cambio Climático). El desarrollo de los proyectos CAC completos pasa por la necesaria selección de adecuados almacenes de CO2 que sean capaces de soportar los efectos de las presiones de inyección, así como asegurar la capacidad de dichos almacenes y la estanqueidad del CO2 en los mismos. La caracterización geológica de un acuífero susceptible de ser almacén de CO2 debe conducir a determinar las propiedades que dicho almacén posee para asegurar un volumen adecuado de almacenamiento, una inyectabilidad del CO2 en el mismo a un ritmo adecuado y la estanqueidad del CO2 en dicho acuífero a largo plazo. El presente trabajo pretende estudiar los parámetros que tienen influencia en el cálculo de la capacidad del almacén, para lo que en primer lugar se ha desarrollado la tecnología necesaria para llevar a cabo la investigación mediante ensayos de laboratorio. Así, se ha desarrollado una patente, "ATAP, equipo para ensayos petrofísicos (P201231913)", con la que se ha llevado a cabo la parte experimental de este trabajo para la caracterización de los parámetros que tienen influencia en el cálculo de la capacidad del almacén. Una vez desarrollada la tecnología, se aborda el estudio de los distintos parámetros que tienen influencia en la capacidad del almacén realizando ensayos con ATAP. Estos ensayos definen el volumen del almacenamiento, llegándose a la conclusión de que en la determinación de este volumen, juegan un papel importante el alcance de los mecanismos trampa, físicos o químicos, del CO2 en el almacén. Ensayos que definen la capacidad del almacén de "aceptar" o "rechazar" el CO2 inyectado, la inyectabilidad, y por último, ensayos encaminados a determinar posibles fugas que se pueden dar a través de los pozos de inyección, definidos estos como caminos preferenciales de fugas en un almacén subterráneo de CO2. Queda de este modo caracterizada la estanqueidad del CO2 en el acuífero a largo plazo y su influencia obvia en la determinación de la capacidad del almacén. Unido al propósito de la estimación de la capacidad del almacén, se encuentra el propósito de asegurar la estanqueidad de dichos almacenes en el tiempo, y adelantarse a la evolución de la pluma de CO2 en el interior de dichos almacenes. Para cumplir este propósito, se ha desarrollado un modelo dinámico a escala de laboratorio, mediante el programa ECLIPSE 300, con el fin de establecer una metodología para el cálculo de la capacidad estimada del almacén, así como el estudio de la evolución de la pluma de CO2 dentro del acuífero a lo largo del tiempo, partiendo de los resultados obtenidos en los ensayos realizados en ATAP y con la modelización de la probeta de roca almacén empleada en dichos ensayos. Presentamos por tanto un trabajo que establece las bases metodológicas para el estudio de la influencia de distintos parámetros petrofísicos en el cálculo de la capacidad del almacén unidos al desarrollo tecnológico de ATAP y su utilización para la determinación de dichos parámetros aplicables a cada acuífero concreto de estudio. ABSTRACT The crisis of modernity –which begins at the end of 19th Century- has been more important due to the knowledge of the limits of economic development, since it appeared to be thought reasonable, the natural resources are finite. In 1972, The Club of Rome analyzed the different options available in order to harmonize the sustainability and the environment development. It was in 1987 when The Global Commission on The Environment and the Development of UN, defined for the first time the concept of Sustainable Development. This definition that was fully incorporated in all the UN programs and it was useful as an axis, for example, in La Cumbre de la Tierra summit in Río de Janeiro in 1992. It seems obvious to satisfy energetic demand, basically after The Industrial Revolution in 19th Century, which represented an increasing use of fossil fuels, therefore greenhouse gases emission and the increasing of global average temperature. This temperature increased in the last 100 years up to 0.74ºC. The major part of the temperature increase is due to the increase observed in Greenhouse gases with human origin, at least with 90% of probability. The most important gas is the CO2 because of its quantity. In the face of the increasing use of fossil fuels, the CCS projects, Carbon Capture and Storage projects, appear as a contribution of sustainable development since it is a technology for avoiding the climate change. In order to evaluate if CCS technology is sustainable, it will be necessary to prove if the capacity for CO2 storage is available or not in a quantity greater than the production one and during the time necessary to keep the CO2 concentration in the atmosphere lower than 450ppmv (concentration imposed by IPCC). The development of full CCS projects goes through the selection of good CO2 storages that are able to support the effects of pressure injection, and assure the capacity of such storages and the watertightness of CO2. The geological characterization of the aquifer that could be potential CO2 storage should lead to determine the properties that such storage has in order to assure the adequate storage volume, the CO2 injectivity in a good rate, and the watertightness of the CO2 in the long term. The present work aims to study the parameters that have influence on the calculation of storage capacity, and for that purpose the appropriate technology has been developed for carrying out the research by mean of laboratory tests. Thus, a patent has been developed, "ATAP, equipo para ensayos petrofísicos (P201231913)", that has been used for developing the experimental part of this work. Once the technology has been developed, the study of different parameters, that have influence on the capacity of the storage, has been addressed developing different tests in ATAP. These tests define the storage volume which is related to the scope of different CO2 trap mechanisms, physical or chemical, in the storage. Tests that define the capacity of the storage to “accept” or “reject” the injected CO2, the injectivity, and tests led to determine possible leakages through injection wells. In this way we could talk about the watertightness in the aquifer in the long term and its influence on the storage capacity estimation. Together with the purpose of the storage capacity estimation, is the purpose of assuring the watertightness of such storages in the long term and anticipating the evolution of CO2 plume inside such aquifers. In order to fulfill this purpose, a dynamic model has been developed with ECLIPSE 300, for stablishing the methodology for the calculation of storage capacity estimation and the evolution of the CO2 plume, starting out with the tests carried out in ATAP. We present this work that establishes the methodology bases for the study of the influence of different petrophysics parameters in the calculation of the capacity of the storage together with the technological development of ATAP and its utilization for the determination of such parameters applicable to each aquifer.

Modelado dinámico y control de maniobras de dispositivos submarinos

Es bien conocido por todos que la Primera Revolución Industrial, que tuvo su inicio en la segunda mitad del Siglo XVIII, conllevó un aumento del uso de los recursos energéticos que no se ha detenido para llegar a los niveles de desarrollo tecnológico, industrial y de calidad de vida, de los que se dispone en la actualidad. A simple vista podría intuirse que para disponer de un mayor nivel tecnológico, industrial, de confort, etc. sea necesario un mayor consumo de energía primaria. La actual generación de energía está principalmente basada en el procesamiento de los diversos compuestos del carbono (hidrocarburos, gases y productos derivados del petróleo), que son contaminantes y además, se agotan. Desde hace unas pocas décadas, la humanidad ha sido consciente que es necesario generar energía a partir de fuentes de origen renovable, y que además resulten menos contaminantes. Así, en la actualidad, se ha llegado a un estado de desarrollo avanzado para la explotación de diversas fuentes de energías como la eólica, a la vez que se comienza a mirar con realismo la posibilidad de explotación de diversas energías de origen marino. Se considera que las energías renovables procedentes de los océanos que se encuentran más desarrolladas tecnológicamente hablando, sin tener en cuenta la energía eólica fuera costa (offshore), son la denominada energía undimotriz o de las olas y la energía de las corrientes marinas, no necesariamente en este orden. El trabajo propuesto en esta Tesis se centra en este último recurso energético y, aunque no se dispone todavía de ningún dispositivo en fase de explotación comercial, la concepción, diseño y desarrollo de dispositivos para la extracción de energía de las corrientes, y su evolución, han sido relativamente rápidos e importantes en estos últimos años. Existen ya diferentes dispositivos en fase de pruebas con resultados muy prometedores. Aunque los dispositivos actuales se encuentran limitados a la explotación energética en zonas de poca profundidad, los diferentes estudios del recurso indican la necesidad de explotar corrientes marinas a mayores profundidades, para lo que se están desarrollando actualmente dispositivos, cuya evolución en lo que a sistemas de fondeo se refiere, está siendo muy parecida a la que se ha producido en los parques eólicos fuera costa, similar a su vez, a la evolución llevada a cabo en las plataformas oceánicas para la explotación de recursos petrolíferos (denominados oil & gas) que se extraen de profundidades cada vez mayores. Las soluciones tecnológicas que resulten válidas han de ser también económicamente viables, y en la actualidad se requiere todavía reducir costos en todas las fases de instalación, explotación y mantenimiento de estos dispositivos, sea cual sea su profundidad de operación. Uno de los focos de estudio para abaratar los costes de explotación en general, pasa por abaratar y reducir los costes en las maniobras necesarias de inmersión (de la superficie del mar a la profundidad de operación) y emersión (de la profundidad de operación a la superficie del mar) de estos dispositivos, para llevar a cabo tareas de mantenimiento in situ, en el mar, y sin necesidad de buques especializados ni de su transporte a tierra. En esta Tesis se propone, en primer lugar, un método para evaluar el ciclo de vida de diversos dispositivos de aprovechamiento de las corrientes marinas. Se evidencia que el coste de la energía así generada sigue siendo no plenamente competitivo, por lo que se requiere avanzar en el abaratamiento de costes, principalmente en la instalación y en su mantenimiento. Para ello se propone como novedad principal, introducir sistemas de control en lazo cerrado para realizar maniobras de instalación y mantenimiento de forma automática. También se aporta un modelo dinámico original y muy sencillo para dispositivos bajo estos movimientos de emersión/inmersión, a partir del cual se han desarrollado los algoritmos de control para el propósito mencionado, que no es otro sino automatizar en todo lo posible las maniobras completas. Los algoritmos de control propuestos han sido validados mediante simulación. Se proponen trayectorias de referencia de movimiento suaves (smooth) similares a las utilizadas en robótica. Estos movimientos de cambios de profundidad en lazo cerrado, combinados con secuencias de movimientos en bucle abierto para cuando el dispositivo interacciona en la superficie libre, han dado lugar a nuevas maniobras completas de instalación y mantenimiento que se presentan en esta Tesis, diferentes a las actuales. Finalmente, y como justificación de la viabilidad económica del método novedoso aportado, se ha realizado un estudio comparativo de los costes de la tecnología propuesta, frente a la tecnología actual. Este nuevo sistema de maniobras automáticas implica un ciclo de vida diferente para los dispositivos de aprovechamiento de la energía de las corrientes, ciclo que se cuantifica a partir de un dispositivo base que ha sido modificado y adaptado para la nueva tecnología propuesta, demostrando su viabilidad tanto técnica como económica. ABSTRACT It’s well known that the First Industrial Revolution started in the second half of the eighteenth century, carried the increasing of the use of energy resource which have not been stopped until reach the present technology, industrial evolution and daily life quality. On the surface, it can be known intuitively that a higher consumption of primary energy resource is demanded for benefiting from a higher technological industrial and daily life level. Today, the generation of energy is mainly based in the processing of carbon products (hydrocarbons, gases and petroleum products) which are pollutants, and additionally, are depleted. From a few decades ago, the humanity is aware the energy should be obtained from renewable resources, which besides, should be cleaner. So, at the present, a technical develop has been gained to exploit several energy source, as wind energy, and, at the same time, the extraction of the marine energy starts to seem as a reality. The renewable marine energies considered more advanced and technically developed, without keeping in mind, the offshore wind energy, are the wave energy and the tidal current energy, not necessarily in that order. This Thesis is focused in this last energy resource, and, although, any device is under commercial operation, the concept, design and develop of this type of devices to extract the tidal current energy and their evolution has been comparatively fast and important the last years. There are several devices under test with promising results. Even through the current devices are limited to lower depth areas, the several studies of the tidal energy resource suggest the need to exploit the marine current at greater depths to what is being developed devices, where their evolution in the anchoring system is being very similar to the evolution performed in the offshore wind farms, which is at the same time, similar to the evolution in the oil and gas exploitation which are extracted to greatest depths. Viable technical solutions should be also viable economically and nowadays the cost in all phases of the project (installation, maintenance and operation) should be decreased whatever the operation depth is. One focus of study to lower the operation cost is the cost decreasing of immersion manoeuvring operations (from sea surface to the operation depth) and immersion manoeuvring operations (from operation depth to the sea surface), therefore the maintenance operations can be performed on – site, in the sea, and no specialized vessels are required to transport the devices from the sea to shore. In this dissertation, firstly is proposed a method to evaluate the life cycle of the tidal energy current devices. It is proved the energy generated by these devices is not fully competitive; therefore, the cost falling is mainly an objective in the installation and the maintenance operations. For that, it is proposed as main novelty, the using of closed loop control systems to perform the automatic installation and manoeuvring operations. It is also contributed with an original and simple dynamic model and for controlling the immersion/emersion movements of these devices, from which the control algorithms are developed in order to automate as much as possible the complete manoeuvring. The control algorithms proposed has been validated by simulations. Reference paths with smooth movements, similar which are used in robotics, are suggested. These movements to change the depth using closed loop control, combined with the sequences in open loop movements when the device is in free surface, have been development for a new complete manoeuvring to installation and maintenance operations which are advanced in this Thesis and they are different to the present manoeuvrings. Finally and as justification of the economic viability of this original method, a comparative cost study between the technology proposed and the current technology is performed. This new automatic manoeuvring system involves a different life cycle for the tidal energy current devices, cycle that is quantified from a base device which has been modified and adapted for the new proposed technology, showing the technical and economic viability.

Co-simulation Methodologies for Hybrid and Electric Vehicle Dynamics

In recent decades, full electric and hybrid electric vehicles have emerged as an alternative to conventional cars due to a range of factors, including environmental and economic aspects. These vehicles are the result of considerable efforts to seek ways of reducing the use of fossil fuel for vehicle propulsion. Sophisticated technologies such as hybrid and electric powertrains require careful study and optimization. Mathematical models play a key role at this point. Currently, many advanced mathematical analysis tools, as well as computer applications have been built for vehicle simulation purposes. Given the great interest of hybrid and electric powertrains, along with the increasing importance of reliable computer-based models, the author decided to integrate both aspects in the research purpose of this work. Furthermore, this is one of the first final degree projects held at the ETSII (Higher Technical School of Industrial Engineers) that covers the study of hybrid and electric propulsion systems. The present project is based on MBS3D 2.0, a specialized software for the dynamic simulation of multibody systems developed at the UPM Institute of Automobile Research (INSIA). Automobiles are a clear example of complex multibody systems, which are present in nearly every field of engineering. The work presented here benefits from the availability of MBS3D software. This program has proven to be a very efficient tool, with a highly developed underlying mathematical formulation. On this basis, the focus of this project is the extension of MBS3D features in order to be able to perform dynamic simulations of hybrid and electric vehicle models. This requires the joint simulation of the mechanical model of the vehicle, together with the model of the hybrid or electric powertrain. These sub-models belong to completely different physical domains. In fact the powertrain consists of energy storage systems, electrical machines and power electronics, connected to purely mechanical components (wheels, suspension, transmission, clutch…). The challenge today is to create a global vehicle model that is valid for computer simulation. Therefore, the main goal of this project is to apply co-simulation methodologies to a comprehensive model of an electric vehicle, where sub-models from different areas of engineering are coupled. The created electric vehicle (EV) model consists of a separately excited DC electric motor, a Li-ion battery pack, a DC/DC chopper converter and a multibody vehicle model. Co-simulation techniques allow car designers to simulate complex vehicle architectures and behaviors, which are usually difficult to implement in a real environment due to safety and/or economic reasons. In addition, multi-domain computational models help to detect the effects of different driving patterns and parameters and improve the models in a fast and effective way. Automotive designers can greatly benefit from a multidisciplinary approach of new hybrid and electric vehicles. In this case, the global electric vehicle model includes an electrical subsystem and a mechanical subsystem. The electrical subsystem consists of three basic components: electric motor, battery pack and power converter. A modular representation is used for building the dynamic model of the vehicle drivetrain. This means that every component of the drivetrain (submodule) is modeled separately and has its own general dynamic model, with clearly defined inputs and outputs. Then, all the particular submodules are assembled according to the drivetrain configuration and, in this way, the power flow across the components is completely determined. Dynamic models of electrical components are often based on equivalent circuits, where Kirchhoff’s voltage and current laws are applied to draw the algebraic and differential equations. Here, Randles circuit is used for dynamic modeling of the battery and the electric motor is modeled through the analysis of the equivalent circuit of a separately excited DC motor, where the power converter is included. The mechanical subsystem is defined by MBS3D equations. These equations consider the position, velocity and acceleration of all the bodies comprising the vehicle multibody system. MBS3D 2.0 is entirely written in MATLAB and the structure of the program has been thoroughly studied and understood by the author. MBS3D software is adapted according to the requirements of the applied co-simulation method. Some of the core functions are modified, such as integrator and graphics, and several auxiliary functions are added in order to compute the mathematical model of the electrical components. By coupling and co-simulating both subsystems, it is possible to evaluate the dynamic interaction among all the components of the drivetrain. ‘Tight-coupling’ method is used to cosimulate the sub-models. This approach integrates all subsystems simultaneously and the results of the integration are exchanged by function-call. This means that the integration is done jointly for the mechanical and the electrical subsystem, under a single integrator and then, the speed of integration is determined by the slower subsystem. Simulations are then used to show the performance of the developed EV model. However, this project focuses more on the validation of the computational and mathematical tool for electric and hybrid vehicle simulation. For this purpose, a detailed study and comparison of different integrators within the MATLAB environment is done. Consequently, the main efforts are directed towards the implementation of co-simulation techniques in MBS3D software. In this regard, it is not intended to create an extremely precise EV model in terms of real vehicle performance, although an acceptable level of accuracy is achieved. The gap between the EV model and the real system is filled, in a way, by introducing the gas and brake pedals input, which reflects the actual driver behavior. This input is included directly in the differential equations of the model, and determines the amount of current provided to the electric motor. For a separately excited DC motor, the rotor current is proportional to the traction torque delivered to the car wheels. Therefore, as it occurs in the case of real vehicle models, the propulsion torque in the mathematical model is controlled through acceleration and brake pedal commands. The designed transmission system also includes a reduction gear that adapts the torque coming for the motor drive and transfers it. The main contribution of this project is, therefore, the implementation of a new calculation path for the wheel torques, based on performance characteristics and outputs of the electric powertrain model. Originally, the wheel traction and braking torques were input to MBS3D through a vector directly computed by the user in a MATLAB script. Now, they are calculated as a function of the motor current which, in turn, depends on the current provided by the battery pack across the DC/DC chopper converter. The motor and battery currents and voltages are the solutions of the electrical ODE (Ordinary Differential Equation) system coupled to the multibody system. Simultaneously, the outputs of MBS3D model are the position, velocity and acceleration of the vehicle at all times. The motor shaft speed is computed from the output vehicle speed considering the wheel radius, the gear reduction ratio and the transmission efficiency. This motor shaft speed, somehow available from MBS3D model, is then introduced in the differential equations corresponding to the electrical subsystem. In this way, MBS3D and the electrical powertrain model are interconnected and both subsystems exchange values resulting as expected with tight-coupling approach.When programming mathematical models of complex systems, code optimization is a key step in the process. A way to improve the overall performance of the integration, making use of C/C++ as an alternative programming language, is described and implemented. Although this entails a higher computational burden, it leads to important advantages regarding cosimulation speed and stability. In order to do this, it is necessary to integrate MATLAB with another integrated development environment (IDE), where C/C++ code can be generated and executed. In this project, C/C++ files are programmed in Microsoft Visual Studio and the interface between both IDEs is created by building C/C++ MEX file functions. These programs contain functions or subroutines that can be dynamically linked and executed from MATLAB. This process achieves reductions in simulation time up to two orders of magnitude. The tests performed with different integrators, also reveal the stiff character of the differential equations corresponding to the electrical subsystem, and allow the improvement of the cosimulation process. When varying the parameters of the integration and/or the initial conditions of the problem, the solutions of the system of equations show better dynamic response and stability, depending on the integrator used. Several integrators, with variable and non-variable step-size, and for stiff and non-stiff problems are applied to the coupled ODE system. Then, the results are analyzed, compared and discussed. From all the above, the project can be divided into four main parts: 1. Creation of the equation-based electric vehicle model; 2. Programming, simulation and adjustment of the electric vehicle model; 3. Application of co-simulation methodologies to MBS3D and the electric powertrain subsystem; and 4. Code optimization and study of different integrators. Additionally, in order to deeply understand the context of the project, the first chapters include an introduction to basic vehicle dynamics, current classification of hybrid and electric vehicles and an explanation of the involved technologies such as brake energy regeneration, electric and non-electric propulsion systems for EVs and HEVs (hybrid electric vehicles) and their control strategies. Later, the problem of dynamic modeling of hybrid and electric vehicles is discussed. The integrated development environment and the simulation tool are also briefly described. The core chapters include an explanation of the major co-simulation methodologies and how they have been programmed and applied to the electric powertrain model together with the multibody system dynamic model. Finally, the last chapters summarize the main results and conclusions of the project and propose further research topics. In conclusion, co-simulation methodologies are applicable within the integrated development environments MATLAB and Visual Studio, and the simulation tool MBS3D 2.0, where equation-based models of multidisciplinary subsystems, consisting of mechanical and electrical components, are coupled and integrated in a very efficient way.

Computational and Experimental Modelling of Mooring Lines Dynamics for Offshore Floating Wind Turbines

El cálculo de cargas de aerogeneradores flotantes requiere herramientas de simulación en el dominio del tiempo que consideren todos los fenómenos que afectan al sistema, como la aerodinámica, la dinámica estructural, la hidrodinámica, las estrategias de control y la dinámica de las líneas de fondeo. Todos estos efectos están acoplados entre sí y se influyen mutuamente. Las herramientas integradas se utilizan para calcular las cargas extremas y de fatiga que son empleadas para dimensionar estructuralmente los diferentes componentes del aerogenerador. Por esta razón, un cálculo preciso de las cargas influye de manera importante en la optimización de los componentes y en el coste final del aerogenerador flotante. En particular, el sistema de fondeo tiene gran impacto en la dinámica global del sistema. Muchos códigos integrados para la simulación de aerogeneradores flotantes utilizan modelos simplificados que no consideran los efectos dinámicos de las líneas de fondeo. Una simulación precisa de las líneas de fondeo dentro de los modelos integrados puede resultar fundamental para obtener resultados fiables de la dinámica del sistema y de los niveles de cargas en los diferentes componentes. Sin embargo, el impacto que incluir la dinámica de los fondeos tiene en la simulación integrada y en las cargas todavía no ha sido cuantificada rigurosamente. El objetivo principal de esta investigación es el desarrollo de un modelo dinámico para la simulación de líneas de fondeo con precisión, validarlo con medidas en un tanque de ensayos e integrarlo en un código de simulación para aerogeneradores flotantes. Finalmente, esta herramienta, experimentalmente validada, es utilizada para cuantificar el impacto que un modelos dinámicos de líneas de fondeo tienen en la computación de las cargas de fatiga y extremas de aerogeneradores flotantes en comparación con un modelo cuasi-estático. Esta es una información muy útil para los futuros diseñadores a la hora de decidir qué modelo de líneas de fondeo es el adecuado, dependiendo del tipo de plataforma y de los resultados esperados. El código dinámico de líneas de fondeo desarrollado en esta investigación se basa en el método de los Elementos Finitos, utilizando en concreto un modelo ”Lumped Mass” para aumentar su eficiencia de computación. Los experimentos realizados para la validación del código se realizaron en el tanque del École Céntrale de Nantes (ECN), en Francia, y consistieron en sumergir una cadena con uno de sus extremos anclados en el fondo del tanque y excitar el extremo suspendido con movimientos armónicos de diferentes periodos. El código demostró su capacidad para predecir la tensión y los movimientos en diferentes posiciones a lo largo de la longitud de la línea con gran precisión. Los resultados indicaron la importancia de capturar la dinámica de las líneas de fondeo para la predicción de la tensión especialmente en movimientos de alta frecuencia. Finalmente, el código se utilizó en una exhaustiva evaluación del efecto que la dinámica de las líneas de fondeo tiene sobre las cargas extremas y de fatiga de diferentes conceptos de aerogeneradores flotantes. Las cargas se calcularon para tres tipologías de aerogenerador flotante (semisumergible, ”spar-buoy” y ”tension leg platform”) y se compararon con las cargas obtenidas utilizando un modelo cuasi-estático de líneas de fondeo. Se lanzaron y postprocesaron más de 20.000 casos de carga definidos por la norma IEC 61400-3 siguiendo todos los requerimientos que una entidad certificadora requeriría a un diseñador industrial de aerogeneradores flotantes. Los resultados mostraron que el impacto de la dinámica de las líneas de fondeo, tanto en las cargas de fatiga como en las extremas, se incrementa conforme se consideran elementos situados más cerca de la plataforma: las cargas en la pala y en el eje sólo son ligeramente modificadas por la dinámica de las líneas, las cargas en la base de la torre pueden cambiar significativamente dependiendo del tipo de plataforma y, finalmente, la tensión en las líneas de fondeo depende fuertemente de la dinámica de las líneas, tanto en fatiga como en extremas, en todos los conceptos de plataforma que se han evaluado. ABSTRACT The load calculation of floating offshore wind turbine requires time-domain simulation tools taking into account all the phenomena that affect the system such as aerodynamics, structural dynamics, hydrodynamics, control actions and the mooring lines dynamics. These effects present couplings and are mutually influenced. The results provided by integrated simulation tools are used to compute the fatigue and ultimate loads needed for the structural design of the different components of the wind turbine. For this reason, their accuracy has an important influence on the optimization of the components and the final cost of the floating wind turbine. In particular, the mooring system greatly affects the global dynamics of the floater. Many integrated codes for the simulation of floating wind turbines use simplified approaches that do not consider the mooring line dynamics. An accurate simulation of the mooring system within the integrated codes can be fundamental to obtain reliable results of the system dynamics and the loads. The impact of taking into account the mooring line dynamics in the integrated simulation still has not been thoroughly quantified. The main objective of this research consists on the development of an accurate dynamic model for the simulation of mooring lines, validate it against wave tank tests and then integrate it in a simulation code for floating wind turbines. This experimentally validated tool is finally used to quantify the impact that dynamic mooring models have on the computation of fatigue and ultimate loads of floating wind turbines in comparison with quasi-static tools. This information will be very useful for future designers to decide which mooring model is adequate depending on the platform type and the expected results. The dynamic mooring lines code developed in this research is based in the Finite Element Method and is oriented to the achievement of a computationally efficient code, selecting a Lumped Mass approach. The experimental tests performed for the validation of the code were carried out at the `Ecole Centrale de Nantes (ECN) wave tank in France, consisting of a chain submerged into a water basin, anchored at the bottom of the basin, where the suspension point of the chain was excited with harmonic motions of different periods. The code showed its ability to predict the tension and the motions at several positions along the length of the line with high accuracy. The results demonstrated the importance of capturing the evolution of the mooring dynamics for the prediction of the line tension, especially for the high frequency motions. Finally, the code was used for an extensive assessment of the effect of mooring dynamics on the computation of fatigue and ultimate loads for different floating wind turbines. The loads were computed for three platforms topologies (semisubmersible, spar-buoy and tension leg platform) and compared with the loads provided using a quasi-static mooring model. More than 20,000 load cases were launched and postprocessed following the IEC 61400-3 guideline and fulfilling the conditions that a certification entity would require to an offshore wind turbine designer. The results showed that the impact of mooring dynamics in both fatigue and ultimate loads increases as elements located closer to the platform are evaluated; the blade and the shaft loads are only slightly modified by the mooring dynamics in all the platform designs, the tower base loads can be significantly affected depending on the platform concept and the mooring lines tension strongly depends on the lines dynamics both in fatigue and extreme loads in all the platform concepts evaluated.

A non-linear analysis of lying a floating pipeline on the seabed

In this article, a model for the determination of displacements, deformations and tensions of a submarine pipeline during the construction is presented. The process is carried out from an initial floating situation to the final laying position on the seabed. The existence of currents and small waves are also considered. Firstly, this technique, usually applied to polyethylene pipelines, is described in this paper as well as some real world examples, as well as the variables that can be modified to control the behavior of the structure. A detailed description of the actions in this process is considered, specially the ones related to marine environment, as Archimedes force, current and sea waves. The behavior of the pipeline is modeled with a non linear elasto dynamic model where geometric non linearities are taken into account. A 3-D beam model, without cross section deformation effects, is developed. Special care is taken in the numerical analysis, developed within an updated lagrangian formulation framework, with the sea bed contact, the follower forces due to the external water pressures and the dynamic actions. Finally, some subroutines are implemented into ANSYS to simulate the two dimensional case, where the whole construction process is achieved. With this software, a sensibility analysis of the bending moments, axial forces and stresses obtained with different values of the control variables in order to optimize the construction steps. These control variables are, the axial load in the pipe, the inundated inner length and the distance of the control barge from the coast.

Essays on Firm Heterogeneity with Empirical Applications in Economic History and Agricultural Economics

This thesis uses models of firm-heterogeneity to complete empirical analyses in economic history and agricultural economics. In Chapter 2, a theoretical model of firm heterogeneity is used to derive a statistic that summarizes the welfare gains from the introduction of a new technology. The empirical application considers the use of mechanical steam power in the Canadian manufacturing sector during the late nineteenth century. I exploit exogenous variation in geography to estimate several parameters of the model. My results indicate that the use of steam power resulted in a 15.1 percent increase in firm-level productivity and a 3.0-5.2 percent increase in aggregate welfare. Chapter 3 considers various policy alternatives to price ceiling legislation in the market for production quotas in the dairy farming sector in Quebec. I develop a dynamic model of the demand for quotas with farmers that are heterogeneous in their marginal cost of milk production. The econometric analysis uses farm-level data and estimates a parameter of the theoretical model that is required for the counterfactual experiments. The results indicate that the price of quotas could be reduced to the ceiling price through a 4.16 percent expansion of the aggregate supply of quotas, or through moderate trade liberalization of Canadian dairy products. In Chapter 4, I study the relationship between farm-level productivity and participation in the Commercial Export Milk (CEM) program. I use a difference-in-difference research design with inverse propensity weights to test for causality between participation in the CEM program and total factor productivity (TFP). I find a positive correlation between participation in the CEM program and TFP, however I find no statistically significant evidence that the CEM program affected TFP.

Does the growth in higher education mean a decline in the quality of degrees? CEPS Working Document No. 405/March 2015

In this paper the authors construct a theory about how the expansion of higher education could be associated with several factors that indicate a decline in the quality of degrees. They assume that the expansion of tertiary education takes place through three channels, and show how these channels are likely to reduce average study time, lower academic requirements and average wages, and inflate grades. First, universities have an incentive to increase their student body through public and private funding schemes beyond a level at which they can keep their academic requirements high. Second, due to skill-biased technological change, employers have an incentive to recruit staff with a higher education degree. Third, students have an incentive to acquire a college degree due to employers’ preferences for such qualifications; the university application procedures; and through the growing social value placed on education. The authors develop a parsimonious dynamic model in which a student, a college and an employer repeatedly make decisions about requirement levels, performance and wage levels. Their model shows that if i) universities have the incentive to decrease entrance requirements, ii) employers are more likely to employ staff with a higher education degree and iii) all types of students enrol in colleges, the final grade will not necessarily induce weaker students to study more to catch up with more able students. In order to re-establish a quality-guarantee mechanism, entrance requirements should be set at a higher level.

Modeling and validation of the thermal behavior of buildings for the development of demand response methods

The representation of the thermal behaviour of the building is achieved through a relatively simple dynamic model that takes into account the effects due to the thermal mass of the building components. The model of a intra-floor apartment has been built in the Matlab-Simulink environment and considers the heat transmission through the external envelope, wall and windows, the internal thermal masses, (i.e. furniture, internal wall and floor slabs) and the sun gain due to opaque and see-through surfaces of the external envelope. The simulations results for the entire year have been compared and the model validated, with the one obtained with the dynamic building simulation software Energyplus.

Downscaled land surface temperatures obtained by a particle smoothing approach, with links to NetCDF files

This dataset contains continuous time series of land surface temperature (LST) at spatial resolution of 300m around the 12 experimental sites of the PAGE21 project (grant agreement number 282700, funded by the EC seventh Framework Program theme FP7-ENV-2011). This dataset was produced from hourly LST time series at 25km scale, retrieved from SSM/I data (André et al., 2015, doi:10.1016/j.rse.2015.01.028) and downscaled to 300m using a dynamic model and a particle smoothing approach. This methodology is based on two main assumptions. First, LST spatial variability is mostly explained by land cover and soil hydric state. Second, LST is unique for a land cover class within the low resolution pixel. Given these hypotheses, this variable can be estimated using a land cover map and a physically based land surface model constrained with observations using a data assimilation process. This methodology described in Mechri et al. (2014, doi:10.1002/2013JD020354) was applied to the ORCHIDEE land surface model (Krinner et al., 2005, doi:10.1029/2003GB002199) to estimate prior values of each land cover class provided by the ESA CCI-Land Cover product (Bontemps et al., 2013) at 300m resolution . The assimilation process (particle smoother) consists in simulating ensemble of LST time series for each land cover class and for a large number of parameter sets. For each parameter set, the resulting temperatures are aggregated considering the grid fraction of each land cover and compared to the coarse observations. Miniminizing the distance between the aggregated model solutions and the observations allow us to select the simulated LST and the corresponding parameter sets which fit the observations most closely. The retained parameter sets are then duplicated and randomly perturbed before simulating the next time window. At the end, the most likely LST of each land cover class are estimated and used to reconstruct LST maps at 300m resolution using ESA CCI-Land Cover. The resulting temperature maps on which ice pixels were masked, are provided at daily time step during the nine-year analysis period (2000-2009).

Modeling & Analysis of Small Hydroelectric Generation and Battery Energy Storage Connected as a Microgrid

Thesis (Master's)--University of Washington, 2016-06

A generalized Markov sampler

A recent development of the Markov chain Monte Carlo (MCMC) technique is the emergence of MCMC samplers that allow transitions between different models. Such samplers make possible a range of computational tasks involving models, including model selection, model evaluation, model averaging and hypothesis testing. An example of this type of sampler is the reversible jump MCMC sampler, which is a generalization of the Metropolis-Hastings algorithm. Here, we present a new MCMC sampler of this type. The new sampler is a generalization of the Gibbs sampler, but somewhat surprisingly, it also turns out to encompass as particular cases all of the well-known MCMC samplers, including those of Metropolis, Barker, and Hastings. Moreover, the new sampler generalizes the reversible jump MCMC. It therefore appears to be a very general framework for MCMC sampling. This paper describes the new sampler and illustrates its use in three applications in Computational Biology, specifically determination of consensus sequences, phylogenetic inference and delineation of isochores via multiple change-point analysis.

Diagnostic goal driven modelling and simulation of multiscale process systems

A systematic goal-driven top-down modelling methodology is proposed that is capable of developing a multiscale model of a process system for given diagnostic purposes. The diagnostic goal-set and the symptoms are extracted from HAZOP analysis results, where the possible actions to be performed in a fault situation are also described. The multiscale dynamic model is realized in the form of a hierarchical coloured Petri net by using a novel substitution place-transition pair. Multiscale simulation that focuses automatically on the fault areas is used to predict the effect of the proposed preventive actions. The notions and procedures are illustrated on some simple case studies including a heat exchanger network and a more complex wet granulation process.

The effect of service evaluations on behavioral intentions and quality of life

Understanding the contribution of marketing to economic and social outcomes is fundamental to broadening the focus of marketing. The authors develop a comprehensive model that integrates the impact of service quality and service satisfaction on both economic and societal outcomes. The model is validated using two random samples involving intensive health services. The results indicate that service quality and service satisfaction significantly enhance quality of life and behavioral intentions, highlighting that customer service has social as well as economic outcomes. This is an important finding given the movement toward recognizing social and environmental outcomes, such as emphasized through triple bottom-line reporting. The findings have important implications for managing service processes, for improving the quality of life of customers, and for enhancing customers' behavioral intentions toward the organization.