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.

Hybrid wind-diesel power plant valuation and optimization using real option theory and dynamic programming

El sistema de energ��a e��lica-diesel h��brido tiene un gran potencial en la prestaci��n de suministro de energ��a a comunidades remotas. En comparaci��n con los sistemas tradicionales de diesel, las plantas de energ��a h��bridas ofrecen grandes ventajas tales como el suministro de capacidad de energ��a extra para "microgrids", reducci��n de los contaminantes y emisiones de gases de efecto invernadero, y la cobertura del riesgo de aumento inesperado del precio del combustible. El principal objetivo de la presente tesis es proporcionar nuevos conocimientos para la evaluaci��n y optimizaci��n de los sistemas de energ��a h��brido e��lico-diesel considerando las incertidumbres. Dado que la energ��a e��lica es una variable estoc��stica, ��sta no puede ser controlada ni predecirse con exactitud. La naturaleza incierta del viento como fuente de energ��a produce serios problemas tanto para la operaci��n como para la evaluaci��n del valor del sistema de energ��a e��lica-diesel h��brido. Por un lado, la regulaci��n de la potencia inyectada desde las turbinas de viento es una dif��cil tarea cuando opera el sistema h��brido. Por otro lado, el bene.cio econ��mico de un sistema e��lico-diesel h��brido se logra directamente a trav��s de la energ��a entregada a la red de alimentaci��n de la energ��a e��lica. Consecuentemente, la incertidumbre de los recursos e��licos incrementa la dificultad de estimar los beneficios globales en la etapa de planificaci��n. La principal preocupaci��n del modelo tradicional determinista es no tener en cuenta la incertidumbre futura a la hora de tomar la decisi��n de operaci��n. Con lo cual, no se prev�� las acciones operativas flexibles en respuesta a los escenarios futuros. El an��lisis del rendimiento y simulaci��n por ordenador en el Proyecto E��lico San Crist��bal demuestra que la incertidumbre sobre la energ��a e��lica, las estrategias de control, almacenamiento de energ��a, y la curva de potencia de aerogeneradores tienen un impacto significativo sobre el rendimiento del sistema. En la presente tesis, se analiza la relaci��n entre la teor��a de valoraci��n de opciones y el proceso de toma de decisiones. La opci��n real se desarrolla con un modelo y se presenta a trav��s de ejemplos pr��cticos para evaluar el valor de los sistemas de energ��a e��lica-diesel h��bridos. Los resultados muestran que las opciones operacionales pueden aportar un valor adicional para el sistema de energ��a h��brida, cuando esta flexibilidad operativa se utiliza correctamente. Este marco se puede aplicar en la optimizaci��n de la operaci��n a corto plazo teniendo en cuenta la naturaleza dependiente de la trayectoria de la pol��tica ��ptima de despacho, dadas las plausibles futuras realizaciones de la producci��n de energ��a e��lica. En comparaci��n con los m��todos de valoraci��n y optimizaci��n existentes, el resultado del caso de estudio num��rico muestra que la pol��tica de operaci��n resultante del modelo de optimizaci��n propuesto presenta una notable actuaci��n en la reducci��n del con- sumo total de combustible del sistema e��lico-diesel. Con el .n de tomar decisiones ��ptimas, los operadores de plantas de energ��a y los gestores de ��stas no deben centrarse s��lo en el resultado directo de cada acci��n operativa, tampoco deber��an tomar decisiones deterministas. La forma correcta es gestionar din��micamente el sistema de energ��a teniendo en cuenta el valor futuro condicionado en cada opci��n frente a la incertidumbre. ABSTRACT Hybrid wind-diesel power systems have a great potential in providing energy supply to remote communities. Compared with the traditional diesel systems, hybrid power plants are providing many advantages such as providing extra energy capacity to the micro-grid, reducing pollution and greenhouse-gas emissions, and hedging the risk of unexpected fuel price increases. This dissertation aims at providing novel insights for assessing and optimizing hybrid wind-diesel power systems considering the related uncertainties. Since wind power can neither be controlled nor accurately predicted, the energy harvested from a wind turbine may be considered a stochastic variable. This uncertain nature of wind energy source results in serious problems for both the operation and value assessment of the hybrid wind-diesel power system. On the one hand, regulating the uncertain power injected from wind turbines is a difficult task when operating the hybrid system. On the other hand, the economic profit of a hybrid wind-diesel system is achieved directly through the energy delivered to the power grid from the wind energy. Therefore, the uncertainty of wind resources has increased the difficulty in estimating the total benefits in the planning stage. The main concern of the traditional deterministic model is that it does not consider the future uncertainty when making the dispatch decision. Thus, it does not provide flexible operational actions in response to the uncertain future scenarios. Performance analysis and computer simulation on the San Cristobal Wind Project demonstrate that the wind power uncertainty, control strategies, energy storage, and the wind turbine power curve have a significant impact on the performance of the system. In this dissertation, the relationship between option pricing theory and decision making process is discussed. A real option model is developed and presented through practical examples for assessing the value of hybrid wind-diesel power systems. Results show that operational options can provide additional value to the hybrid power system when this operational flexibility is correctly utilized. This framework can be applied in optimizing short term dispatch decisions considering the path-dependent nature of the optimal dispatch policy, given the plausible future realizations of the wind power production. Comparing with the existing valuation and optimization methods, result from numerical example shows that the dispatch policy resulting from the proposed optimization model exhibits a remarkable performance in minimizing the total fuel consumption of the wind-diesel system. In order to make optimal decisions, power plant operators and managers should not just focus on the direct outcome of each operational action; neither should they make deterministic decisions. The correct way is to dynamically manage the power system by taking into consideration the conditional future value in each option in response to the uncertainty.

An accurate model for simulating energetic behavior of PV grid connected inverters

This paper proposes a new model for characterizing the energetic behavior of grid connected PV inverters. The model has been obtained from a detailed study of main loss processes in small size PV inverters in the market. The main advantage of the used method is to obtain a model that comprises two antagonistic features, since both are simple, easy to compute and apply, and accurate. One of the main features of this model is how it handles the maximum power point tracking (MPPT) and the efficiency: in both parts the model uses the same approach and it is achieved by two resistive elements which simulate the losses inherent to each parameter. This makes this model easy to implement, compact and refined. The model presented here also includes other parameters, such as start threshold, standby consumption and islanding behavior. In order to validate the model, the values of all the parameters listed above have been obtained and adjusted using field measurements for several commercial inverters, and the behavior of the model applied to a particular inverter has been compared with real data under different working conditions, taken from a facility located in Madrid. The results show a good fit between the model values and the real data. As an example, the model has been implemented in PSPICE electronic simulator, and this approach has been used to teach grid-connected PV systems. The use of this model for the maintenance of working PV facilities is also shown.

Toward a consolidation of the CPV-specific-test procedures for inverters

The inverter in a photovoltaic system assures two essential functions. The first is to track the maximum power point of the system IV curve throughout variable environmental conditions. The second is to convert DC power delivered by the PV panels into AC power. Nowadays, in order to qualify inverters, manufacturers and certifying organisms use mainly European and/or CEC efficiency standards. The question arises if these are still representative of CPV system behaviour. We propose to use a set of CPV ��� specific weighted average and a representative dynamic response to have a better determination of the static and dynamic MPPT efficiencies. Four string-sized commercial inverters used in real CPV plants have been tested.

The segmental approximation in multijunction solar cells

The segmental approach has been considered to analyze dark and light I-V curves. The photovoltaic (PV) dependence of the open-circuit voltage (Voc), the maximum power point voltage (Vm), the efficiency (?) on the photogenerated current (Jg), or on the sunlight concentration ratio (X), are analyzed, as well as other photovoltaic characteristics of multijunction solar cells. The characteristics being analyzed are split into monoexponential (linear in the semilogarithmic scale) portions, each of which is characterized by a definite value of the ideality factor A and preexponential current J0. The monoexponentiality ensures advantages, since at many steps of the analysis, one can use the analytical dependences instead of numerical methods. In this work, an experimental procedure for obtaining the necessary parameters has been proposed, and an analysis of GaInP/GaInAs/Ge triple-junction solar cell characteristics has been carried out. It has been shown that up to the sunlight concentration ratios, at which the efficiency maximum is achieved, the results of calculation of dark and light I-V curves by the segmental method fit well with the experimental data. An important consequence of this work is the feasibility of acquiring the resistanceless dark and light I-V curves, which can be used for obtaining the I-V curves characterizing the losses in the transport part of a solar cell.

Acute effects of endurance exercise on jumping and kicking performance in top-class young soccer players

The aim of this study was to examine the acute effects of endurance exercise on jumping and kicking performance in young soccer players. Twenty-one top-class young soccer players (16.1��0.2 years) performed a countermovement jump test and a maximal instep soccer kick test before and after running for 20 min on a treadmill at 80% of their individual maximum heart rate. Two force platforms were used to obtain the following parameters during the countermovement jump: jump height, maximum power, maximum power relative to body mass, maximum vertical ground reaction force, maximum vertical ground reaction force relative to body mass, and maximum vertical ground reaction force applied to each leg. Maximum vertical ground reaction force and maximum vertical ground reaction force relative to body mass applied to the support leg during the kicks were also calculated with a force platform. The kicking motion was recorded using a three-dimensional motion-capture system. Maximum velocity of the ball, maximum linear velocity of the toe, ankle, knee and hip, and linear velocity of the toe at ball contact during the kicks were calculated. Non-significant differences were found in the parameters measured during the countermovement jump and the maximal instep soccer kick test before and after running, suggesting that the jumping and kicking performances of top-class young soccer players were not significantly affected after 20 min treadmill running at 80% of their individual maximum heart rate.

Envelope amplifier based on switching capacitors for high efficiency RF amplifiers

Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B, or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has high peak-to-average power ratio. The Kahn envelope elimination and restoration technique is used to enhance the efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class E) with a highly efficient envelope amplifier in order to obtain a linear and highly efficient RF amplifier. This paper presents a solution for the envelope amplifier based on a multilevel converter in series with a linear regulator. The multilevel converter is implemented by employing voltage dividers based on switching capacitors. The implemented envelope amplifier can reproduce any signal with a maximum spectral component of 2 MHz and give instantaneous maximum power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, the implemented prototypes have up to 20% higher efficiency than linear regulators used as a conventional solution.

Energy payback time of grid connected pv systems: comparison between tracking and fixed systems

A review of existing studies about LCA of PV systems has been carried out. The data from this review have been completed with our own figures in order to calculate the Energy Payback Time of double and horizontal axis tracking and fixed systems. The results of this metric span from 2 to 5 years for the latitude and global irradiation ranges of the geographical area comprised between ���10��� to 10��� of longitude, and 30��� to 45��� of latitude. With the caution due to the uncertainty of the sources of information, these results mean that a GCPVS is able to produce back the energy required for its existence from 6 to 15 times during a life cycle of 30 years. When comparing tracking and fixed systems, the great importance of the PV generator makes advisable to dedicate more energy to some components of the system in order to increase the productivity and to obtain a higher performance of the component with the highest energy requirement. Both double axis and horizontal axis trackers follow this way, requiring more energy in metallic structure, foundations and wiring, but this higher contribution is widely compensated by the improved productivity of the system.

Transverse galloping of two-dimensional bodies having a rhombic cross-section

Transverse galloping is a type of aeroelastic instability characterized by oscillations perpendicular to wind direction, large amplitude and low frequency, which appears in some elastic two-dimensional bluff bodies when they are subjected to an incident flow, provided that the flow velocity exceeds a threshold critical value. Understanding the galloping phenomenon of different cross-sectional geometries is important in a number of engineering applications: for energy harvesting applications the interest relies on strongly unstable configurations but in other cases the purpose is to avoid this type of aeroelastic phenomenon. In this paper the aim is to analyze the transverse galloping behavior of rhombic bodies to understand, on the one hand, the dependence of the instability with a geometrical parameter such as the relative thickness and, on the other hand, why this cross-section shape, that is generally unstable, shows a small range of relative thickness values where it is stable. Particularly, the non-galloping rhombus-shaped prism?s behavior is revised through wind tunnel experiments. The bodies are allowed to freely move perpendicularly to the incoming flow and the amplitude of movement and pressure distributions on the surfaces is measured.

Impact of automatic meetering infrastructure on multiutility business models

In the last decade energy utility sector has undergone major changes in terms of liberalization, increased competition, efforts in improving energy efficiency, and in new technological solution such as smart meter and grid operations. There are new information technology solutions (e.g. Advanced Metering Infrastructure /AMI ) on the horizon that will not only introduce new technical and organizational concepts, but have a very strong potential to radically change modus operandi of utility companies. Coordinated, multi-utility programs can help accelerate the development and market success of new high-efficiency technologies. These programs provide opportunities for researchers to develop new high-efficiency equipment for manufacturers to sell this new equipment with utility help, for utilities to increase the amount of energy they save from incentive programs, and for consumers to benefit from lower utility bills and a cleaner environment (as energy is reduced, pollutants produced at power plants decline).

Adaptaci��n de una central t��rmica de carb��n a la Directiva de Emisiones Industriales

El proyecto que se presenta a continuaci��n recoge la adaptaci��n de una Central T��rmica de carb��n al cumplimiento de la DIRECTIVA 2010/75/UE DEL PARLAMENTO EUROPEO Y DEL CONSEJO de 24 de noviembre de 2010 sobre las emisiones industriales. La Central sobre la que se realiza el proyecto tiene un grupo t��rmico de carb��n suscritico refrigerado por agua, con una potencia a plena carga de 350 MWe y de 190 MWe a m��nimo t��cnico. Genera 1 090 t/h de vapor a 540 ��C y 168 kg/cm2 funcionando a plena carga. Actualmente las emisiones de NOx son de 650 mg/m3, (condiciones normales, seco, 6 % O2). El objeto del proyecto es reducir estas emisiones a un valor m��ximo de 200 mg/m3 en las mismas condiciones. El proyecto analiza detalladamente las condiciones actuales de operaci��n de la instalaci��n en cuanto a combustible utilizado, horas de funcionamiento, condiciones clim��ticas y producci��n. Se analiza as�� mismo, todas las t��cnicas disponibles en mercado para la reducci��n del NOx, diferenciando entre medidas primarias (act��an sobre los efectos de formaci��n) y secundarias (limpieza de gases). Las medidas primarias ya est��n implementadas en la central, por tanto, el proyecto plantea la reducci��n con medidas secundarias. De las medidas secundarias analizadas se ha seleccionado la instalaci��n de un Reactor de Reducci��n Selectiva Catal��tica (Reactor SCR). Tras un an��lisis de los diferentes reactores y catalizadores disponibles se ha seleccionado un reactor de configuraci��n High-dust, una disposici��n de catalizador en 3 capas m��s 1, cuyos componentes est��n basados en ��xidos met��licos (TiO2, V2O5, WO3) y estructura laminar. Se ha buscado la instalaci��n del reactor para operar a una temperatura inferior a 450 ��C. Como agente reductor se ha seleccionado NH3 a una diluci��n del 24,5 %. El proyecto recoge tambi��n el dise��o de todo el sistema de almacenamiento, evaporaci��n, diluci��n e inyecci��n de amoniaco. El resultado del proyecto garantiza una concentraci��n en los gases de salida por la chimenea inferior 180 mg/m3(n) de NOx. La reducci��n del NOx a los l��mites establecidos, tienen un coste por MWh neto generado para la central, trabajando 60 % a plena carga y 40 % a m��nimo t��cnico y una amortizaci��n de 10 a��os, de 4,10 ���/MWh. ABSTRACT The following project shows the compliance adjustment of a coal-fired power station to the 2010/75/EU Directive of the European Parliament and Council 24th November 2010 on industrial emissions. The project is based on a power station with a subcritical thermal coal unit, cooled with water, with a maximum power of 350 MWe and a technical minimum of 190 MWe. It produces 1 090 t/h of steam at 540 �� C and 168 kg/cm2 operating under full load. Currently, NOx emissions are 650 mg / m3 (normal conditions, dry, 6% O2). The project aims to reduce these emissions to a maximum value of 200 mg / m3 under the same conditions. The project analyses in detail the current operating conditions of the system in terms of fuel used, hours of operation, climatic conditions and production. In addition, it also analyses every available technique of NOx reduction on the market, distinguishing between primary (acting on the effects of formation) and secondary measures (gas cleaning). Primary measures are already implemented in the plant, thus proposing reduction with secondary measures. Among the secondary measures analyzed, it has been selected to install a Selective Catalytic Reduction Reactor (SCR Reactor). Having researched the different reactors and catalysts available, for the reactor has been selected High-dust configuration, an arrangement of catalyst in 3 layers plus 1, whose components are based on metal oxides (TiO2, V2O5, WO3) and laminar structure. The reactor has been sought facility to operate at a temperature below 450 �� C. NH3 diluted to 24,5 % has been selected as reducing agent. The project also includes the design of the entire storage system, evaporation, dilution and ammonia injection. The results of the project ensure a gas concentration in the lower chimney exit below 180 mg / m3(n) NOx. The reduction of NOx to the established limits has a cost per net MWh generated in the plant, working at 60% of full load and at 40% of technical minimum, with an amortization of 10 years, 4,10 ��� / MWh.

Towards energy sustainability in ecolodges for latin America: a case in the bolivian Amazon

This project, funded by the Programa Iberoam��ricano de Ciencia y Tecnolog��a para el Desarrollo (CYTED), analyses the energy service requirements in sustainable tourism and will spread knowledge about renewable energies among the ecotourism stakeholders of Latin America. The target groups are local communities in protected areas, because they are the less up to date groups and, frequently, they are living in the most fragile ecosystems, but also the most fertile in biodiversity; their living standard is very low and the ecotourism can be a successful economic resource. The regions considered are ecosystems in Latin America, which have some protection degree, and are managed by local communities. The selected countries to implement renewable energy infrastructures in ecolodges are: Bolivia, Ecuador and Peru. Also low cost telecommunications infrastructures will be installed to improve the diffusion among potential clients of the ecolodges, in order to permit direct reservation of the services.

CMOS integration of AlN based piezoelectric microcantilevers

El gran crecimiento de los sistemas MEMS (Micro Electro Mechanical Systems) as�� como su presencia en la mayor��a de los dispositivos que usamos diariamente despert�� nuestro inter��s. Paralelamente, la tecnolog��a CMOS (Complementary Metal Oxide Semiconductor) es la tecnolog��a m��s utilizada para la fabricaci��n de circuitos integrados. Adem��s de ventajas relacionadas con el funcionamiento electr��nico del dispositivo final, la integraci��n de sistemas MEMS en la tecnolog��a CMOS reduce significantemente los costes de fabricaci��n. Algunos de los dispositivos MEMS con mayor variedad de aplicaciones son los microflejes. Estos dispositivos pueden ser utilizados para la extracci��n de energ��a, en microscopios de fuerza at��mica o en sensores, como por ejemplo, para biodetecci��n. Los materiales piezoel��ctricos m��s com��nmente utilizados en aplicaciones MEMS se sintetizan a altas temperaturas y por lo tanto no son compatibles con la tecnolog��a CMOS. En nuestro caso hemos usado nitruro de alumino (AlN), que se deposita a temperatura ambiente y es compatible con la tecnolog��a CMOS. Adem��s, es biocompatible, y por tanto podr��a formar parte de un dispositivo que act��e como biosensor. A lo largo de esta tesis hemos prestado especial atenci��n en desarrollar un proceso de fabricaci��n r��pido, reproducible y de bajo coste. Para ello, todos los pasos de fabricaci��n han sido minuciosamente optimizados. Los par��metros de sputtering para depositar el AlN, las distintas t��cnicas y recetas de ataque, los materiales que act��an como electrodos o las capas sacrificiales para liberar los flejes son algunos de los factores clave estudiados en este trabajo. Una vez que la fabricaci��n de los microflejes de AlN ha sido optimizada, fueron medidos para caracterizar sus propiedades piezoel��ctricas y finalmente verificar positivamente su viabilidad como dispositivos piezoel��ctricos. ABSTRACT The huge growth of MEMS (Micro Electro Mechanical Systems) as well as their presence in most of our daily used devices aroused our interest on them. At the same time, CMOS (Complementary Metal Oxide Semiconductor) technology is the most popular technology for integrated circuits. In addition to advantages related with the electronics operation of the final device, the integration of MEMS with CMOS technology reduces the manufacturing costs significantly. Some of the MEMS devices with a wider variety of applications are the microcantilevers. These devices can be used for energy harvesting, in an atomic force microscopes or as sensors, as for example, for biodetection. Most of the piezoelectric materials used for these MEMS applications are synthesized at high temperature and consequently are not compatible with CMOS technology. In our case we have used aluminum nitride (AlN), which is deposited at room temperature and hence fully compatible with CMOS technology. Otherwise, it is biocompatible and and can be used to compose a biosensing device. During this thesis work we have specially focused our attention in developing a high throughput, reproducible and low cost fabrication process. All the manufacturing process steps of have been thoroughly optimized in order to achieve this goal. Sputtering parameters to synthesize AlN, different techniques and etching recipes, electrode material and sacrificial layers are some of the key factors studied in this work to develop the manufacturing process. Once the AlN microcantilevers fabrication was optimized, they were measured to characterize their piezoelectric properties and to successfully check their viability as piezoelectric devices.

Estrategias de desarrollo sostenible de la arquitectura del oasis de M���hamid, desierto del Sahara

Esta investigaci��n se plantea con la hip��tesis radical de c��mo habitar el desierto de forma sostenible, desde una actitud pragm��tica y experimental basada en el progreso. La justificaci��n se basa en primer lugar en los 2.000 millones de personas en el mundo que viven en entornos des��rticos, el 80% de ellas, en pa��ses en desarrollo, porque el 40% de la superficie terrestre est�� bajo amenaza de desertificaci��n afectando al 37% de la poblaci��n mundial, con 12 millones de hect��reas al a��o perdidas por esa causa, y por ��ltimo, porque se considera el desierto como un entorno de gran atractivo y potencial. El contenido de la investigaci��n se estructura en tres movimientos: posicionamiento, mirada y acci��n: Desde el posicionamiento se define en primer lugar la sostenibilidad, aportando un nuevo diagrama donde se incorpora el ��mbito arquitect��nico como uno de los pilares principales, y, posteriormente, se establecen los criterios de evaluaci��n de la sostenibilidad, aportando un sistema de indicadores donde se incorporan par��metros adecuados a las circunstancias del oasis. Del mismo modo, se estudian y analizan metodolog��as de actuaci��n y proyectos de desarrollo sostenible existentes que enmarcan el estado del arte, constatando la dificultad de adaptaci��n de los mismos a las condiciones de los oasis, por lo que se elabora una metodolog��a propia donde se modifica la din��mica estrat��gica, de forma que el impulso se plantea desde la acci��n social, a trav��s de hip��tesis de estrategias basadas en sistemas low-cost, autoconstruidas, asumibles econ��micamente y de implantaci��n factible. El caso de estudio espec��fico radica en la situaci��n extrema de las condiciones en el oasis de M���hamid, donde se evidencia un proceso de desintegraci��n y abandono. Esto es debido a una acumulaci��n de circunstancias externas e internas, de m��ltiples factores: naturales y antr��picos que afectan al oasis, llevando al extremo las condiciones clim��ticas y la escasez de recursos, naturales y artificiales. Factores como el cambio clim��tico, la sequ��a, los cambios en las pol��ticas del agua, la amenaza de desertificaci��n, los conflictos sociales, el desequilibrio ecol��gico, la escasez econ��mica, la crisis energ��tica, la obsolescencia arquitect��nica, el patrimonio construido pr��cticamente destruido, y la malentendida nueva arquitectura. Es importante constatar la escasa documentaci��n gr��fica existente sobre la zona de actuaci��n lo que ha conllevado un amplio trabajo de documentaci��n, tanto cartogr��fica como de observaci��n directa, aportada a la tesis como investigaci��n de elaboraci��n propia. La mirada anal��tica al caso de estudio permite conocer los recursos disponibles y las potencialidades latentes del oasis de M���hamid, que permitir��n actuar para subvertir la din��mica involutiva imperante, de forma que los dibujos iniciales de apropiaci��n contextual y an��lisis cr��ticos derivan en mapas de acci��n diagramados conformados por un sistema de objetos y la definici��n de estrategias transversales, deconstruyendo el pasado y reconstruyendo el futuro, incorporando sistemas alternativos que se definen en 7 l��neas estrat��gicas de acci��n formuladas desde los 3 ��mbitos relacionados con el ecosistema: ecol��gico, socio- econ��mico y arquitect��nico. As��, la tesis defiende la acci��n arquitect��nica como impulsora del desarrollo sostenible, apoyada en 3 elementos: - la creaci��n de objetos ���tecnoartesanos���, para el aprovechamiento de los recursos energ��ticos - las transformaciones arquitect��nicas, para reformular el h��bitat desde la eficiencia energ��tica y el progreso - y el impulso de acciones cotidianas, que redefinan las relaciones sociales, creando entornos cooperativos y colaborativos. En el ��mbito ecol��gico se proponen actuaciones anti desertificaci��n mediante incubadoras de ��rboles; sistemas alternativos de gesti��n del agua, como la lluvia s��lida; estrategias de potenciaci��n de la producci��n agr��cola; la construcci��n de mecanismos de obtenci��n de energ��a a partir de residuos, como los paneles solares con botellas PET. En el ��mbito socioecon��mico se plantean nuevas formas de acci��n social y de reactivaci��n econ��mica. Por ��ltimo, en el ��mbito urbano-arquitect��nico, se incorporan modificaciones morfol��gicas a la arquitectura existente y una relectura contempor��nea de la tierra, como material que permite nuevas geometr��as, obteniendo arena petrificada por procesos microbiol��gicos, y potenciando la tierra como recurso art��stico. Esta tesis es un punto de partida, recoge sistemas, estrategias y experiencias, para funcionar como un est��mulo o impulso dinamizador del futuro desarrollo sostenible del oasis, abriendo v��as de investigaci��n y experimentaci��n. ABSTRACT This research puts forth the radical hypothesis of how to inhabit the desert in a sustainable way, using a pragmatic and experimental approach based on progress. The justification for this resides in the fact that there are 2,000 million people in the world living in desert environments, 80% of them in developing countries. Forty percent of the earth���s surface is under threat of desertification, affecting 37% of the world population and with 12 million hectares being lost each year. And finally, the desert is considered as an attractive environment and therefore, with great potential. The content of the research is structured in three main sections: positioning, observation and action: As a point of departure, sustainability is defined, proposing a new framework where architecture is incorporated as one of the main pillars. Then, the criteria for evaluating sustainability are established. These provide a system of indicators, which incorporate parameters based on the specific circumstances of the oasis. Methodologies and existing sustainable development projects that represent the state-of-the-art are analyzed, discussing the difficulty of adapting them to conditions of oases. A methodology that modifies strategic concepts is developed, whereby the catalyst is social action, and strategies are developed based on low-cost, self-built, and feasible implementation systems. The specific case study lies in the extreme conditions in the oasis of M'hamid, where a process of decay and neglect is evident. This deterioration is due to an accumulation of external and internal circumstances, and of natural and anthropogenic factors that affect the oasis, leading to extreme weather conditions and a shortage of both natural and artificial resources. Factors include; climate change, drought, changes in water policies, the threat of desertification, social conflicts, ecological imbalance, economic shortage, the energy crisis, architectural obsolescence, destruction of built heritage, and misunderstood new architecture. It is important to note the extremely limited graphic information about the area has led me to produce an extensive archive of maps and drawings, many developed by direct observation, that contribute to the research. The case study analysis of the oasis of M'hamid examines the resources available and the latent potential to slow the prevailing trend towards deterioration. The initial drawings of contextual appropriation and critical analysis result in maps and diagrams of action, which are formed by a system of objects and the definition of strategies. These can be thought of as understanding or ���deconstructing��� the past to reconstruct the future. Alternative approaches defined in seven strategies for action are based on three fields related to the ecosystem: ecological, socioeconomic and architectural. Thus, the thesis defends architectural action to promote sustainable development, based on three elements: - The creation of "techno-artisans", to make use of energy resources - Architectural changes, to reformulate habitat in terms of energy efficiency and progress - And the promotion of everyday actions, to redefine social relations, creating cooperative and collaborative environments. In the ecological field, I propose anti-desertification actions such as; tree incubators, alternative water management systems(such as solid rain),; strategies to empower the agricultural production, energy from low-cost systems made out from recycled materials(such as solar panels from PET bottles or wind turbine from bicycle wheels). In the socioeconomic sphere, I propose to implement new forms of social action and economic regeneration. Finally, within the urban and architectural field, I propose morphological changes to the existing architecture and a contemporary reinterpretation of the earth as a material that allows new geometries, creating petrified sand by microbiological processes or enhancing nature as an artistic and energy resource. This thesis is a starting point. It collects systems, strategies and experiences to serve as a stimulus or dynamic momentum for future sustainable development of the oasis, opening new avenues of research and experimentation. R��SUM�� Cette recherche part d'une hypoth��se radicale : comment habiter le d��sert de fa��on durable, et ce �� partir d'une approche pragmatique et exp��rimentale bas��e sur le progr��s. Cette hypoth��se se justifie en raison des 2 milliards de personnes qui dans le monde habitent des environnements d��sertiques, 80% d'entre eux dans des pays en voie de d��veloppement, mais aussi parce que 40% de la surface de la plan��te est sous menace de d��sertification, un ph��nom��ne affectant 37% de la population mondiale et qui cause la perte de 12 millions d'hectares par an; et enfin parce que le d��sert est consid��r�� comme un environnement tr��s attrayant et fort d���un grand potentiel. Le contenu de la recherche se divise en trois mouvements: le positionnement, le regard et l'action : Du point de vue du positionnement on d��finit tout d'abord la durabilit��, pr��sentant un nouveau sch��ma o�� le domaine de l'architecture devient un des principaux piliers, et, par la suite, des crit��res d'��valuation de la durabilit�� sont ��tablis, en fournissant un syst��me d���indicateurs qui int��gre les param��tres appropri��s aux circonstances de l'oasis. De m��me, des m��thodologies et des projets de d��veloppement durable existants sont ��tudi��s et analys��s, ce qui encadre l'��tat de l'art, remarquant la difficult�� de les adapter aux conditions des oasis. De cette difficult�� d��coule l'��laboration d'une m��thodologie qui modifie la dynamique strat��gique, de sorte que l'impulsion provient de l'action sociale, �� travers des hypoth��ses de strat��gie bas��es sur des syst��mes low-cost, auto-construits, et de mise en oeuvre ��conomiquement viable. Le cas d'��tude sp��cifique r��side en la situation extr��me des conditions de l'oasis de M���hamid, o�� un processus de d��cadence et de n��gligence est ��vident. Cela est d�� �� une accumulation de circonstances externes et internes, de multiples facteurs: les facteurs naturels et anthropiques qui affectent l'oasis, menant �� l'extr��me les conditions m��t��orologiques et la p��nurie de ressources, autant naturelles qu'artificielles. Des facteurs tels que le changement climatique, la s��cheresse, les changements dans les politiques de l'eau, la menace de la d��sertification, les conflits sociaux, le d��s��quilibre ��cologique, la p��nurie ��conomique, la crise de l'��nergie, l'obsolescence architecturale, le patrimoine b��ti pratiquement d��truit et une mauvais compr��hensif de la nouvelle architecture. Il est important de de faire remarquer le peu d'informations graphiques du domaine d'action, ce qui a conduit �� un vaste travail de documentation, autant cartographique que relative �� l'observation directe. Cette documentation s'ajoute �� la th��se en tant que recherche propre. Le regard analytique sur le cas d'��tude permet de conna��tre les ressources disponibles et le potentiel latent de l'oasis de M���hamid, qui agiront pour renverser la dynamique d'involution en vigueur. Ainsi, les premiers dessins d'appropriation contextuelle et analyse critique deviennent des cartes d'action sch��matis��es form��es par un syst��me d'objets et la d��finition de strat��gies transversales, qui d��construisent le pass�� et reconstruisent l'avenir, en incorporant des syst��mes alternatifs qui se d��finissent sur 7 lignes strat��giques d'action formul��es �� partir des 3 domaines en relation avec l�����cosyst��me: l�����cologique, le socio-��conomique et l'architectural. Ainsi, la th��se d��fend l'action architecturale en tant que promotrice du d��veloppement durable, et ce bas�� sur 3 ��l��ments: - la cr��ation d'objets "technoartisans" pour l'exploitation des ressources ��nerg��tiques - les modifications architecturales, pour reformuler l'habitat du point de vue de l'efficacit�� ��nerg��tique et le progr��s - et la promotion des actions quotidiennes, pour red��finir les relations sociales, et la cr��ation d'environnements de coop��ration et collaboration. Dans le domaine de l'��cologie des actions de lutte contre la d��sertification sont propos��es �� travers des p��pini��res d'arbres, des syst��mes alternatifs de gestion de l'eau comme par exemple la pluie solide, des strat��gies de mise en valeur de la production agricole, la construction de m��canismes de production d'��nergie �� partir de r��sidus, tels que les panneaux solaires ou les bouteilles en PET. Dans le domaine socio-��conomique, l'on propose de nouvelles formes d'action sociale et de reprise ��conomique. Enfin, dans le domaine de l'urbain et de l'architectural, on incorpore des changements morphologiques �� l'architecture existante et une relecture contemporaine de la terre, comme mat��riau qui permet de nouvelles g��om��tries, en obtenant du sable p��trifi�� par des proc��d��s microbiologiques et en mettant en valeur la terre comme une ressource artistique. Cette th��se n'est qu'un point de d��part. Elle recueille des syst��mes, des strat��gies et des exp��riences pour servir de stimulus ou d'impulsion dynamisatrice du futur d��veloppement durable de l'oasis, en ouvrant des voies de recherche et d'exp��rimentation.

Aerodin��mica experimental de elementos de parques energ��ticos

La creciente demanda de energ��a el��ctrica y la necesidad de implementar energ��as no contaminantes hace que las llamadas tecnolog��as verdes sean cada d��a m��s solicitadas. Entre estas tecnolog��as encontramos la energ��a solar y la energ��a e��lica; ambas tienen una trayectoria de uso e investigaci��n bastante amplia, sin embargo a��n presentan problemas de fondo que impiden dar mayor impulso a su uso. El objetivo de la presente tesis es presentar soluciones a problemas de optimizaci��n en campos conversores de energ��a. Para ello se analizan y resuelven dos problemas por medio de t��cnicas de aerodin��mica experimental: el primero sobre campos de colectores solares y el segundo sobre campos e��licos. Las t��cnicas de medici��n utilizadas en aerodin��mica, y en el presente trabajo, son: medici��n de cargas, anemometr��a de hilo caliente, velocimetr��a por imagen de part��culas y escaneo de presiones; adem��s de un an��lisis estad��stico de los datos. En el primer caso se ensayan experimentalmente colectores solares parab��licos en donde, por cuestiones de seguridad o por protecci��n contra el viento, se utilizan cercas. ��stas modifican el comportamiento del flujo corriente abajo y se ha encontrado que la distancia a la cual se colocan, as�� como el tipo de cercas (s��lida o permeable), modifican las cargas estructurales a las que los colectores est��n expuestos. Los resultados demuestran que existe una distancia cr��tica en la cual la presencia de la cerca aumenta la carga en lugar de disminuirla, por lo cual la selecci��n adecuada del parapeto y la distancia a la cual se coloca son de suma importancia para la optimizaci��n de la estructura. En el segundo caso se ensaya experimentalmente y simula num��ricamente la estela de turbinas e��licas por medio de discos porosos. En donde un disco permeable simula el rotor de una turbina. El disco es capaz de semejar la estela y los efectos que ��sta puede causar corriente abajo. Los resultados muestran que seleccionando adecuadamente la porosidad, es posible simular coeficientes de empuje similares a los desarrollados por los aerogeneradores, adem��s la estela y sus efectos son semejantes a los medidos en campo. ABSTRACT The called green energy technologies are increasingly required because of the growing demand for electricity and the need to implement nonpolluting energy. Among the green energy technologies it is found the solar and the wind energy, both have a history of use and fairly extensive research; however they still have problems which limit to give them further impetus to its use. The aim of this thesis is to present solutions to optimization problems in energy harvesting. To this end it is analysed, and solved, two problems by means of techniques in experimental aerodynamics: the first issue with regard to parabolic troughs and the second about wind farms. The measurement techniques commonly used in aerodynamics, and used in this research work, are: measurement of loads, hot wire anemometry, particle image velocimetry and scanning of pressures; where data are collected and then an statistical analysis is done. In the first case it is tested parabolic troughs where, either for security reasons or protection against the wind actions, fences are used. These fences modify the behaviour of flow downstream and it was found that the distance at which they are placed, and the type of fences (solid or permeable) modify the structural loads to which the parabolic troughs are exposed. The results show that there is a critical distance at which the presence of the fence increases the load instead of protecting the parabolic trough, hence making the proper selection of the parapet and the distance at which it stands are paramount for the optimization of the structure. In the second case it is tested, experimentally and numerically, the wake of wind turbines by means of porous disks; where the permeable disc simulates a turbine rotor. The disc is able to mimic the wake and the effects that it can cause downstream. The results show that by properly selecting the porosity, it is possible to simulate drag coefficients similar to those developed by wind turbines; moreover the porous disk wake and its effects are similar to those measured on field.