Increasing attention to climate change in combination with ever-growing energy consumption worldwide has boosted the demand for new green energy sources. Wave power is developing in many different branches to become part of the new era of electricity production. This thesis deals with a wave power system in its primary stages of development. The system was investigated in order to estimate its potential to produce electric power from sea waves. It is a system consisting of a moored buoy to which the energy is transferred when the wave tilts the buoy in the pitch direction. Due to the increased pitch angle, an amount of liquid contained inside the buoy is allowed to flow via ramps to an upper container, from where it flows down through a hydroelectric turbine. A computer program was used to calculate the properties of the buoy in sea waves. Another program was written in MATLAB to simulate the movements in sea waves and from a set of given parameters calculate the power output. A brief economic study was made to determine if the power output was large enough for the concept to be of financial interest to any future investors. The results show that the wave power system produced 0.9 kW in a wave climate equal to that off the coast of Hanstholm, Denmark, and 1.6 kW in a wave climate off the coast of San Diego, USA. The economic study shows that the power output needed to be improved by a factor of at least five to have a chance of being economically viable. A number of enhancements were suggested to increase the power output of the system, and further investigation could be of use to improve the concept. The created computer simulation model, as well as the results in this thesis could be valuable in any future research on the concept.

This MSc thesis was a project performed in a start-up that develops sustainable devices to exploit renewable energies, specifically in the field of energy harvesting in small scale. The objective of the thesis is to demonstrate the importance of developing the technical side of a project together with the development of the market. The idea is to enhance the success possibilities and work to get to the market as fast as possible with a minimum sellable product using the resources as efficiently as possible. The market analysis was the first step to be performed to understand what the start-up was getting into, at the beginning it was clear that the generator should be targeted to power remote applications that require small amounts of energy and a market that is not suitable for present technologies such as solar PV or micro wind turbines. After this a series of potential markets were identified in order to limit the research and three opportunities were selected. The buoy market was chosen, it has several sub-markets and the AtoN buoys, Fishing buoys and Meteorological buoys were considered the most important and suitable ones. Once the market was defined, the needs of the clients and users were discovered through research in the form of interviews and bibliographical research. Later on an experimental rig was used to test several models of the prototype under different parameters to select one that was close to what was demanded and that can actually be built. This approach was useful to dedicate resources efficiently, specially time and money. The last part of the thesis was to propose a sustainable business model describing a go-to-market strategy that considered both the limitations of the technology and the testing performed in the scope of this project and the expectations of the market for the proposed product. The methodology was a mixed use of business tools learned in the courses and the experiences of the people who were close to the start-up. There is a final reflection at the conclusions that describe the day-to-day of the start-up and the experiences learned as well as the recommendations for future work.

L’objectif de ce travail de thèse est d’étudier l’interaction des ondes électromagnétiques en bande L avec les vagues côtières déferlantes, en particulier pour un observateur situé à proximité de la surface. Le travail s’attache à effectuer une modélisation électromagnétique précise en lien étroit avec le modèle hydrodynamique. Pour modéliser et calculer les champs électromagnétiques diffusés par les vagues déferlantes, nous utilisons une approche numérique par intégrale de frontière, notamment la Méthode des Moments (MdM). Dans ce cadre, nous focalisons le travail sur la problématique de la fiabilité et la convergence du calcul numérique pour des géométries de forte courbure comme peuvent l’être des surfaces de vagues déferlantes. Après une analyse approfondie de la problématique, nous montrons qu’une solution fondée sur la Méthode des Moments d’Ordre Supérieur (MdM-OS) combinée avec la technique de maillage Non Uniform Rational Basis Splines (NURBS) permet d’améliorer les performances de la méthode MdM-Classique. En parallèle du travail de modélisation électromagnétique, nous nous attachons à introduire un modèle hydrodynamique capable de simuler le plus fidèlement possible le mouvement et la déformation des vagues à proximité de la côte. Nous retenons une modélisation hydrodynamique basée sur la Méthode Désingularisée. Cette approche méthodologique nous permet d’étudier l’évolution des vagues en fonction de la pente du fond, de la hauteur relative et de la cambrure des vagues. La combinaison des résultats issus de la modélisation numérique électromagnétique et de la description hydrodynamique permettent ainsi d’évaluer l’évolution des champs électromagnétiques diffusés par les vagues côtières déferlantes en fonction du temps pour trois types de déferlement standard : glissant, plongeant et gonflant. / The purpose of this thesis work is to study the interaction of electromagnetic waves in L bandwith breaking coastal sea waves, in particular for an observer situated close to the surface. The work attempts to realize a precise electromagnetic modeling in narrow link with hydrodynamic model. To model and calculate electromagnetic fields scattered by breaking sea waves, we use a numerical approach by boundary integral technique, in particular Method of Moments (MoM). In this frame, we focus on the reliability and the convergence problem of numerical computation for strong curvature geometries as the surfaces of breaking sea waves are. After a thorough analysis of the problem, we show that a solution based on Higher-Order Method of Moments (HO-MoM) combined with Non Uniform Rational Basis Splines (NURBS) meshing technique allows the improvement of the performances of Classical-MoM. In parallel of the work on electromagnetic modeling, we attempt to introduce a hydrodynamic model able to precisely simulate the movement and the deformation of waves near the coast. We choose a hydrodynamic modeling based on Desingularized Method. This methodological approach allows the study of the evolution of waves according to the bottom slope, the relative height and the wave steepness. The combination of the results obtained from the numerical electromagnetic modeling and from the hydrodynamic description allows us to estimate the evolution of the electromagnetic fields scattered by breaking coastal sea waves according to time for three types of standard breaking : spilling, plunging and surging.

Orientador: Celso Kazuyuki Morooka / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-04T17:58:55Z (GMT). No. of bitstreams: 1 ChampiFarfan_David_M.pdf: 3228003 bytes, checksum: 8b3ed290e87307aa0cc1afcdd9c2ecf3 (MD5) Previous issue date: 2005 / Resumo: Na atualidade as descobertas de óleo a grandes profundidades no mar têm levado ao desenvolvimento de campos localizados numa profundidade aproximada de 3000m, sendo então o sistema de Riser Híbrido Auto-Sustentável uma alternativa atraente. O presente trabalho apresenta os modelos matemáticos que descrevem o comportamento estático e dinâmico de um riser vertical com bóia de sub-superfície nas direções in-line, que é a direção da onda e correnteza no mar, e a direção transversal, perpendicular à direção in-line. Apresentam-se também simulações numéricas em diferentes condições de onda e correnteza e o seu efeito combinado, assim como o estudo paramétrico para as principais variáveis que influenciam no comportamento dinâmico e estático / Abstract: Nowadays, the oil discoveries at big depths in the sea have taken to the development of fields located in an approach depth of 3000m, being the Self Standing Hybrid Riser an attractive alternative. The present work presents the mathematical models that describe the static and dynamic behavior of a Vertical riser with a subsurface buoy in the directions inline, that it is the direction of the wave and currents in the sea, and the transversal, that is perpendicular to the in-line direction. Numerical simulations in different conditions of wave and currents are also presented and its combined effect is studied, as well as the parametric study for the main variable that influences its dynamic and static behavior / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo