Controlador com FPGA para um motor-in-wheel CA de fluxo axial

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e de Computadores

Optimal behavior of responsive residential demand considering hybrid phase change materials

Due to communication and technology developments, residential consumers are enabled to participate in Demand Response Programs (DRPs), control their consumption and decrease their cost by using Household Energy Management (HEM) systems. On the other hand, capability of energy storage systems to improve the energy efficiency causes that employing Phase Change Materials (PCM) as thermal storage systems to be widely addressed in the building applications. In this paper, an operational model of HEM system considering the incorporation of more than one type of PCM in plastering mortars (hybrid PCM) is proposed not only to minimize the customerâ s cost in different DRPs but also to guaranty the habitantsâ  satisfaction. Moreover, the proposed model ensures the technical and economic limits of batteries and electrical appliances. Different case studies indicate that implementation of hybrid PCM in the buildings can meaningfully affect the operational pattern of HEM systems in different DRPs. The results reveal that the customerâ s electricity cost can be reduced up to 48% by utilizing the proposed model.

Thickening of phase change materials (PCM) to avoid segregation

Estudi elaborat a partir d’una estada a Çukurova University, Turquia, al juliol del 2006. L’emmagatzematge d’energia tèrmica ha atret interès en aplicacions tèrmiques com l’aigua calenta, la calefacció i l’aire condicionat. Aquests sistemes són útils per corregir la no coincidència entre la oferta i la demanda d’energia. Principalment hi ha dos tipus de sistemes d’emmagatzematge d’energia tèrmica, emmagatzematge amb calor sensible i amb calor latent. L’emmagatzematge amb calor latent és particularment atractiu degut a la seva habilitat de donar una densitat d’emmagatzematge d’energia més alt i la seva característica d’emmagatzemar calor a una temperatura constant corresponent a la temperatura de transició de fase de la substància emmagatzemadora de calor. Les salts hidratades orgàniques tenen certes avantatges com a materials d’emmagatzematge de calor latent sobre els materials orgànics. En canvi, quan les salts hidratades s’utilitzen com a materials de canvi de fase (PCM) apareixen alguns problemes en les aplicacions d’emmagatzematge de calor latent. Aquests són el subrefredament de les salts hidratades quan es congelen degut a les seves dèbils propietats de nucleació, i la separació de fase que hi apareix degut a una fusió incongruent. En aquest estudi, s’estabilitza sal de Glauber (Na2SO4.10H2O) amb diferents concentracions de poliacrilamida i gelatina per prevenir la fusió incongruent. Per prevenir el subrefredament s’utilitza un agent nucleant amb una estructura cristal•lina semblant a la de la sal de Glauber. La capacitat d’emmagatzematge de calor de les mostres de PCM estabilitzades amb diferents concentracions de gels polimèrics es determinen amb DCS i amb el mètode T-history.

Monitorització de rendiment i accounting de centres de computació grid

El Port d'Informació Científica és un centre de Computació Grid de referència que dona suport a comunitats científiques, com el LHC (CERN). Al PIC, trobem una gran varietat de tecnologies que proporcionen serveis al centre. Des de l'arquitectura i elements de la xarxa, fins a recursos informàtics de computació, sistemes d'emmagatzematge a disc i cinta magnètica, bases de dades (ORACLE/PostgreSQL). El projecte consisteix en el disseny i implementació d'una base de dades col·lectora de tota la informació rellevant dels diferents sistemes del centre, i un portal web on mostrar tots els valors i gràfiques, tot basat en programari lliure.

Nanostructuració d'òxids mitjançant mètodes de solució química avançats i nanolitografia tova

Un dels reptes tecnològics més importants del segle XXI és el desenvolupament i organització de materials funcionals a escala nanomètrica ja que permet modificar-ne les propietats fonamentals i generar-ne de noves. En el cas dels òxids complexos aquesta tecnologia ha generat grans perspectives en diferents àrees d’estudi perquè presenten propietats molt interessants com la magnetoresistència colossal, superconductivitat o multiferroicitat. En particular, en l’òxid complex superconductor YBa2Cu3O7 (YBCO) s’ha demostrat que la formació de capes superconductores sobre plantilles nanoestructurades o bé la formació de nanocompostos en una matriu superconductora permet millorar de manera espectacular les seves propietats (corrent crític). Aquests resultats introduiran canvis paradigmàtics en la tecnologia de l’energia elèctrica (cables, motors, generadors) i en totes aquelles aplicacions que requereixin camps magnètics intensos. Ara bé, cal aconseguir-ho mitjançant tècniques de baix cost i que permetin un fàcil escalat. Durant els 4 mesos que s’ha disfrutat de l’ajut BP s’han preparat amb èxit noves capes primes superconductores nanoestructurades mitjançant la introducció d’una fase secundària nanomètrica complexa, Ba2YTaO6 (BYTO), dins la matriu d’YBCO pel mètode de baix cost de deposició de solucions químiques. Aquesta nova composició ha donat lloc a un augment significatiu de les propietats superconductores comparat amb la fase tradicional d’YBCO i per tant tenen gran potencial per fabricar futures cintes superconductores.

Hadoop : processament distribuït de gran volum de dades en el núvol d'Apache

Avui en dia es genera un volum increïble de dades de diferents tipus i que provenen de multitud d'orígens. Els sistemes d'emmagatzematge i processament distribuït són els elements tecnològics que fan possible capturar aquest allau de dades i permeten donar-ne un valor a través d'anàlisis diversos. Hadoop, que integra un sistema d'emmagatzematge i processament distribuïts, s'ha convertit en l'estàndard de-facto per a aplicacions que necessiten una gran capacitat d'emmagatzematge, inclús de l'ordre de desenes de PBs. En aquest treball farem un estudi de Hadoop, analitzarem l'eficiència del seu sistema de durabilitat i en proposarem una alternativa.

Report on theorerical results of power generation and conversion

Experimental results of a new controller able to support bidirectional power flow in a full-bridge rectifier with boost-like topology are obtained. The controller is computed using port Hamiltonian passivity techniques for a suitable generalized state space averaging truncation system, which transforms the control objectives, namely constant output voltage dc-bus and unity input power factor, into a regulation problem. Simulation results for the full system show the essential correctness of the simplifications introduced to obtain the controller, although some small experimental discrepancies point to several aspects that need further improvement.

Hybrid model of a double-fed induction machine and back-to-back converter

This report details the port interconnection of two subsystems: a power electronics subsystem (a back-to-back AC/AC converter (B2B), coupled to a phase of the power grid), and an electromechanical subsystem (a doubly-fed induction machine (DFIM), coupled mechanically to a flywheel and electrically to the power grid and to a local varying load). Both subsystems have been essentially described in previous reports (deliverables D 0.5 and D 4.3.1), although some previously unpublished details are presented here. The B2B is a variable structure system (VSS), due to the presence of control-actuated switches: however from a modelling and simulation, as well as a control-design, point of view, it is sensible to consider modulated transformers (MTF in the bond-graph language) instead of the pairs of complementary switches. The port-Hamiltonian models of both subsystems are presents and coupled through a power-preserving interconnection, and the Hamiltonian description of the whole system is obtained; detailed bond-graphs of all the subsystems and the complete system are provided.

Determinação de compostos fenólicos por cromatografia líquida de alta eficiência isocrática durante estacionamento da erva-mate

Different phenolic compound, 5- caffeoylquinic acid (5-CQA), caffeic acid (AC) and rutin (Ru) contents of yerba-mate (Ilex paraguariensis) Brazilian samples of 06 different regions of São Mateus - Paraná, during natural and accelerated industrial storage, were evaluated. For quantification, a reverse phase HPLC isocratic method was developed and validated using methanol:water (35:65 v/v) acidified with 0.5% acetic acid as mobile phase and a photodiode array detector. The six sample global average contents were (34.90 and 36.10 mg g-1) for 5-CQA, (0.18 mg g-1 and 0.23 mg g-1) for AC and (7.12 and 7.18 mg g-1) for Ru, respectively, for the natural and accelerated storage systems. The results showed that the 5-CQA and Ru content are kept constant during the storage while AC content increase only during accelerated storage.

Apply of energy storages in electricity distribution networks and reserve capacity applications

The Thesis is dedicated to development of an operative tool to support decision making of battery energy storages implementation in distribution networks. The basics of various battery technologies, their perspectives and challenges are represented in the Thesis. Mathematical equations that describe economic effect from battery energy storage installation are offered. The main factors that influence profitability of battery settings have been explored and mathematically defined. Mathematical model and principal trends of battery storage profitability under an impact of the major factors are determined. The meaning of annual net value was introduced to show the difference between savings and required costs. The model gives a clear vision for dependencies between annual net value and main factors. Proposals for optimal network and battery characteristics are suggested.

Electrical Safety of Island Operated Low Voltage DC Network

Today, renewable energy technologies and modern power electronics have made it feasible to implement low voltage direct current (LVDC) microgrids (MGs) ca-pable to island operation. Such LVDC networks are particularly useful in remote areas. However, there are still pending issues in island operated LVDC MGs like electrical safety and controlled operation, which should be addressed before wide-scale implementation. This thesis is focused on the overall protection of an island operated LVDC network concept, including protection against electrical shocks, mains equipment protection and protection of photovoltaic (PV) power sources and battery energy storage systems (BESSs). The topic is approached through ex-amination of the safety hazards and the appropriate methods to protect against them, comprising considerations for earthing system selection and realisation of the protection system.

Thermal modelling of commercial lithium-ion batteries

The accelerating adoption of electrical technologies in vehicles over the recent years has led to an increase in the research on electrochemical energy storage systems, which are among the key elements in these technologies. The application of electrochemical energy storage systems for instance in hybrid electrical vehicles (HEVs) or hybrid mobile working machines allows tolerating high power peaks, leading to an opportunity to downsize the internal combustion engine and reduce fuel consumption, and therefore, CO2 and other emissions. Further, the application of electrochemical energy storage systems provides an option of kinetic and potential energy recuperation. Presently, the lithium-ion (Li-ion) battery is considered the most suitable electrochemical energy storage type in HEVs and hybrid mobile working machines. However, the intensive operating cycle produces high heat losses in the Li-ion battery, which increase its operating temperature. The Li-ion battery operation at high temperatures accelerates the ageing of the battery, and in the worst case, may lead to a thermal runaway and fire. Therefore, an appropriate Li-ion battery cooling system should be provided for the temperature control in applications such as HEVs and mobile working machines. In this doctoral dissertation, methods are presented to set up a thermal model of a single Li-ion cell and a more complex battery module, which can be used if full information about the battery chemistry is not available. In addition, a non-destructive method is developed for the cell thermal characterization, which allows to measure the thermal parameters at different states of charge and in different points of cell surface. The proposed models and the cell thermal characterization method have been verified by experimental measurements. The minimization of high thermal non-uniformity, which was detected in the pouch cell during its operation with a high C-rate current, was analysed by applying a simplified pouch cell 3D thermal model. In the analysis, heat pipes were incorporated into the pouch cell cooling system, and an optimization algorithm was generated for the estimation of the optimalplacement of heat pipes in the pouch cell cooling system. An analysis of the application of heat pipes to the pouch cell cooling system shows that heat pipes significantly decrease the temperature non-uniformity on the cell surface, and therefore, heat pipes were recommended for the enhancement of the pouch cell cooling system.

Managing groups of files in a rule oriented data management system (iRODS)

The iRODS system, created by the San Diego Supercomputing Centre, is a rule oriented data management system that allows the user to create sets of rules to define how the data is to be managed. Each rule corresponds to a particular action or operation (such as checksumming a file) and the system is flexible enough to allow the user to create new rules for new types of operations. The iRODS system can interface to any storage system (provided an iRODS driver is built for that system) and relies on its’ metadata catalogue to provide a virtual file-system that can handle files of any size and type. However, some storage systems (such as tape systems) do not handle small files efficiently and prefer small files to be packaged up (or “bundled”) into larger units. We have developed a system that can bundle small data files of any type into larger units - mounted collections. The system can create collection families and contains its’ own extensible metadata, including metadata on which family the collection belongs to. The mounted collection system can work standalone and is being incorporated into the iRODS system to enhance the systems flexibility to handle small files. In this paper we describe the motivation for creating a mounted collection system, its’ architecture and how it has been incorporated into the iRODS system. We describe different technologies used to create the mounted collection system and provide some performance numbers.

European resarch school on large scale solar thermal - SHINE

The Solar HeatIntegration NEtwork (SHINE) is a European research school in which 13 PhDstudents in solar thermal technologies are funded by the EU Marie-Curie program.It has five PhD course modules as well as workshops and seminars dedicated to PhDstudents both within the project as well as outside of it. The SHINE researchactivities focus on large solar heating systems and new applications: ondistrict heating, industrial processes and new storage systems. The scope ofthis paper is on systems for district heating for which there are five PhDstudents, three at universities and two at companies. The PhD students allstarted during the early part of 2014 and their initial work has concentratedon literature studies and on setting up models and data collection to be usedfor validation purposes. The PhD students will complete their studies in2017-18.

Avaliação de HPA e BTEX no solo e água subterrânea, em postos de revenda de combustíveis: estudo de caso na cidade de Natal -RN

The retail fuel stations are partially or potentially polluters and generators of environmental accidents, potentially causing contamination of underground and surface water bodies, soil and air. Leaks in fuel retail stations´ underground storage systems are often detected in Brazil and around the world. Monoaromatic hydrocarbons, BTEX (benzene, toluene, ethylbenzene and xylenes) and polycyclic aromatic hydrocarbons (PAHs) are an indication of the presence of contamination due to its high toxicity. This paper presents a case study of contamination in a Fuel Retail Station by petroleum derivative products in the city of Natal. For identification and quantification of the hydrocarbons, EPA analytical methods were used. The values of benzene quantified by EPA method 8021b CG-PID/FID, ranged from 1.164 to 4.503 mg.Kg-1 in soil samples, and from 12.10 to 27,639 μg.L-1 in underground water samples. Among the PAHs, naphthalene and anthracene showed the most significant results in soil samples, 0.420 to 15.46 mg.Kg-1 and 0.110 to 0,970 mg.Kg-1, respectively. In underground water samples, the results for Naphthalene varied between 0.759 and 614.7 μg.L-1. PAHs were quantified by EPA Method 8270 for GCMS. All of the results for the chemical analysis were compared with the values for the CONAMA 420/2009 resolution. The results for benzene (27,639 μg.L-1) showed levels highly above the recommended by the CONAMA 420 resolution, wherein the maximum permissible for underground water is 5 μg.L-1. This is a worrying factor, since underground water makes up 70% of the city of Natal´s water supply