La thèse présente un modèle d’optimisation mathématique ainsi qu’une méthodologie d’étude pour la conception optimale de réseaux de chaleur et de froid flexibles et intégrant des technologies innovantes (les smart réseaux ou réseaux 4e génération). Dans ce modèle, différentes contraintes énergétiques, économiques et environnementales sont alors considérées. Le modèle considère des réseaux de chaud (ou de froid) à différents niveaux de température, ainsi que différents sites de production et demande d’énergie. Le tracé du réseau ainsi que la configuration de l’ensemble des systèmes de production sont obtenus en minimisant soit l'exergie totale consommée soit le coût total pour l’investissement et l’opération des systèmes. Le modèle mathématique développé est formulé en un problème MINLP multi-période. Les contraintes du modèle sont présentées dans plusieurs modèles imbriqués. Le premier modèle M1 est multi-période et inclut les contraintes d’échanges avec le réseau et un moyen de stockage thermique. Le deuxième modèle, appelé M2, contient l’ensemble du modèle M1 ainsi que des nouvelles contraintes permettant de dimensionner des pompes à chaleur à COP variable. Le troisième modèle M3 inclut le modèle M2 ainsi que de nouvelles contraintes pour le tracé géographique des réseaux et la prise en compte des flux d’électricité. Une méthodologie d’étude est aussi présentée, permettant, à l’aide du modèle M3 développé, de traiter des cas d’étude complexes et réalistes. La méthodologie propose une décomposition du problème selon trois étapes consécutives. Cette méthodologie est alors utilisée et illustrée pour un cas d’étude complexe : l’optimisation d’un nouveau quartier, considérant des PAC, un stockage de chaleur saisonnier et de la production PV. / This thesis presents a mathematical optimization model and a methodology for the optimal design of district heating and cooling networks. The various constraints in energy balances, costs and environmental criteria can be considered in order to propose structures of flexible and innovative networks.The model allows the consideration of heating (or cooling) networks at different temperature levels, as well as different production sites and heat demands. The network’s layout as well as the optimal architecture of the heat production systems are achieved by minimizing either the total exergy consumed or the total cost for the investment and operation of the systems.The developed mathematical model is formulated into a multi-period MINLP problem. The constraints of the model are presented in nested models. The first model M1 considers the multi-period aspect and includes the constraints related to the heat exchanges between production/demand streams with the network and a thermal storage. The second model, called M2, contains the entire model M1 as well as new constraints for sizing heat pumps with variable COP. The model M3 includes the model M2 as well as new constraints for the geographical layout of the networks and the consideration of electricity balance in the problem.A methodology is also presented making it possible, using the model M3, to deal with complex and realistic case studies. The methodology proposes a decomposition of the problem following three consecutive steps. This methodology is then used for the optimization of a new district, considering heat pumps, seasonal heat storage and PV production.

Energy consumption rates have been dramatically increasing on a global scale within the last few decades. A significant role in this increase is subjected by the recent high temperature levels especially at summer time which caused a rapid increase in the air conditioning demands. Such phenomena can be clearly observed in developing countries, especially those in hot climate regions, where people depend mainly on conventional air conditioning systems. These systems often show poor performance and thus negatively impact the environment which in turn contributes to global warming phenomena. In recent years, the demand for urban or district cooling technologies and networks has been increasing significantly as an alternative to conventional systems due to their higher efficiency and improved ecological impact. However, to obtain an efficient design for district cooling systems is a complex task that requires considering a wide range of cooling technologies, various network layout configuration possibilities, and several energy resources to be integrated. Thus, critical decisions have to be made regarding a variety of opportunities, options and technologies. The main objective of this thesis is to develop a tool to obtain preliminary design configurations and operation patterns for district cooling energy systems by performing roughly detailed optimizations and further, to introduce a decision-making approach to help decision makers in evaluating the economic aspects and environmental performance of urban cooling systems at an early design stage. Different aspects of the subject have been investigated in the literature by several researchers. A brief survey of the state of the art was carried out and revealed that mathematical programming models were the most common and successful technique for configuring and designing cooling systems for urban areas. As an outcome of the survey, multi objective optimization models were decided to be utilized to support the decision-making process. Hence, a multi objective optimization model has been developed to address the complicated issue of decision-making when designing a cooling system for an urban area or district. The model aims to optimize several elements of a cooling system such as: cooling network, cooling technologies, capacity and location of system equipment. In addition, various energy resources have been taken into consideration as well as different solar technologies such as: trough solar concentrators, vacuum solar collectors and PV panels. The model was developed based on the mixed integer linear programming method (MILP) and implemented using GAMS language. Two case studies were investigated using the developed model. The first case study consists of seven buildings representing a residential district while the second case study was a university campus district dominated by non-residential buildings. The study was carried out for several groups of scenarios investigating certain design parameters and operation conditions such as: Available area, production plant location, cold storage location constraints, piping prices, investment cost, constant and variable electricity tariffs, solar energy integration policy, waste heat availability, load shifting strategies, and the effect of outdoor temperature in hot regions on the district cooling system performance. The investigation consisted of three stages, with total annual cost and CO2 emissions being the first and second single objective optimization stages. The third stage was a multi objective optimization combining the earlier two single objectives. Later on, non-dominated solutions, i.e. Pareto solutions, were generated by obtaining several multi objective optimization scenarios based on the decision-makers’ preferences. Eventually, a decision-making approach was developed to help decision-makers in selecting a specific solution that best fits the designers’ or decision makers’ desires, based on the difference between the Utopia and Nadir values, i.e. total annual cost and CO2 emissions obtained at the single optimization stages. / Die Energieverbrauchsraten haben in den letzten Jahrzehnten auf globaler Ebene dramatisch zugenommen. Diese Erhöhung ist zu einem großen Teil in den jüngst hohen Temperaturniveaus, vor allem in der Sommerzeit, begründet, die einen starken Anstieg der Nachfrage nach Klimaanlagen verursachen. Solche Ereignisse sind deutlich in Entwicklungsländern zu beobachten, vor allem in heißen Klimaregionen, wo Menschen vor allem konventionelle Klimaanlagensysteme benutzen. Diese Systeme verfügen meist über eine ineffiziente Leistungsfähigkeit und wirken sich somit negativ auf die Umwelt aus, was wiederum zur globalen Erwärmung beiträgt. In den letzten Jahren ist die Nachfrage nach Stadt- oder Fernkältetechnologien und -Netzwerken als Alternative zu konventionellen Systemen aufgrund ihrer höheren Effizienz und besseren ökologischen Verträglichkeit satrk gestiegen. Ein effizientes Design für Fernkühlsysteme zu erhalten, ist allerdings eine komplexe Aufgabe, die die Integration einer breite Palette von Kühltechnologien, verschiedener Konfigurationsmöglichkeiten von Netzwerk-Layouts und unterschiedlicher Energiequellen erfordert. Hierfür ist das Treffen kritischer Entscheidungen hinsichtlich einer Vielzahl von Möglichkeiten, Optionen und Technologien unabdingbar. Das Hauptziel dieser Arbeit ist es, ein Werkzeug zu entwickeln, das vorläufige Design-Konfigurationen und Betriebsmuster für Fernkälteenergiesysteme liefert, indem aureichend detaillierte Optimierungen durchgeführt werden. Zudem soll auch ein Ansatz zur Entscheidungsfindung vorgestellt werden, der Entscheidungsträger in einem frühen Planungsstadium bei der Bewertung städtischer Kühlungssysteme hinsichtlich der wirtschaftlichen Aspekte und Umweltleistung unterstützen soll. Unterschiedliche Aspekte dieser Problemstellung wurden in der Literatur von verschiedenen Forschern untersucht. Eine kurze Analyse des derzeitigen Stands der Technik ergab, dass mathematische Programmiermodelle die am weitesten verbreitete und erfolgreichste Methode für die Konfiguration und Gestaltung von Kühlsystemen für städtische Gebiete sind. Ein weiteres Ergebnis der Analyse war die Festlegung von Mehrzieloptimierungs-Modelles für die Unterstützung des Entscheidungsprozesses. Darauf basierend wurde im Rahmen der vorliegenden Arbeit ein Mehrzieloptimierungs-Modell für die Lösung des komplexen Entscheidungsfindungsprozesses bei der Gestaltung eines Kühlsystems für ein Stadtgebiet oder einen Bezirk entwickelt. Das Modell zielt darauf ab, mehrere Elemente des Kühlsystems zu optimieren, wie beispielsweise Kühlnetzwerke, Kühltechnologien sowie Kapazität und Lage der Systemtechnik. Zusätzlich werden verschiedene Energiequellen, auch solare wie Solarkonzentratoren, Vakuum-Solarkollektoren und PV-Module, berücksichtigt. Das Modell wurde auf Basis der gemischt-ganzzahlig linearen Optimierung (MILP) entwickelt und in GAMS Sprache implementiert. Zwei Fallstudien wurden mit dem entwickelten Modell untersucht. Die erste Fallstudie besteht aus sieben Gebäuden, die ein Wohnviertel darstellen, während die zweite Fallstudie einen Universitätscampus dominiert von Nichtwohngebäuden repräsentiert. Die Untersuchung wurde für mehrere Gruppen von Szenarien durchgeführt, wobei bestimmte Designparameter und Betriebsbedingungen überprüft werden, wie zum Beispiel die zur Verfügung stehende Fläche, Lage der Kühlanlage, örtliche Restriktionen der Kältespeicherung, Rohrpreise, Investitionskosten, konstante und variable Stromtarife, Strategie zur Einbindung der Solarenergie, Verfügbarkeit von Abwärme, Strategien der Lastenverschiebung, und die Wirkung der Außentemperatur in heißen Regionen auf die Leistung des Kühlsystems. Die Untersuchung bestand aus drei Stufen, wobei die jährlichen Gesamtkosten und die CO2-Emissionen die erste und zweite Einzelzieloptimierungsstufe darstellen. Die dritte Stufe war ein Pareto-Optimierung, die die beiden ersten Ziele kombiniert. Im Anschluss wurden nicht-dominante Lösungen, also Pareto-Lösungen, erzeugt, indem mehrere Pareto-Optimierungs-Szenarien basierend auf den Präferenzen der Entscheidungsträger abgebildet wurden. Schließlich wurde ein Ansatz zur Entscheidungsfindung entwickelt, um Entscheidungsträger bei der Auswahl einer bestimmten Lösung zu unterstützen, die am besten den Präferenzen des Planers oder des Entscheidungsträgers enstpricht, basierend auf der Differenz der Utopia und Nadir Werte, d.h. der jährlichen Gesamtkosten und CO2-Emissionen, die Ergebnis der einzelnen Optimierungsstufen sind.

Dynamic Rating (DR) is usually associated with unlocking the capacity of power lines and transformers using available information on weather conditions. Our studies show that Dynamic Rating is a broad concept that requires further study and development. The capacity of the majority of power devices is highly dependent on the heat transfer properties of the materials which the devices are made of. To ensure correct power limits of the equipment, one must take into consideration not only the power load, but also ambient conditions, such as: temperature, wind speed, wind direction, solar irradiation, humidity, pressure, radiation into the atmosphere and magnetic losses. Dynamic rating is created as an alternative to standard constant rating that is designed with reference to extreme weather and load conditions. Some areas are more likely than others to experience extreme weather conditions, which have a chance of occurring only a few days per year for short periods of time. Such a distribution of weather parameters gives an opportunity to embed existing material properties of the power equipment and achieve a better utilization of the grid. The following thesis is divided into two simultaneous topics: Dynamic line rating and Dynamic transformer rating. The division is motivated by the importance of analysing the operation of the above-mentioned parts of the power network in greater detail. Power lines and transformers play a significant part in grid planning and have a potential to result in economic benefits when used with DR. The main focus of the doctoral project "Dynamic rating of power lines and transformers for wind energy integration" is on exploring potential ways to connect power generated from wind to the grid with the help of dynamic rating technologies. Therefore, great focus of the work lies on the analysis of DR connection of variable energy sources such as wind farms. The thesis presents the comparison of different line rating methods and proposes a new way of their classification. Evaluation of dynamic line rating application has shown the possibility to expand the power grid with additional capacity from wind power generation. Literature analysis and detailed evaluation of the conductor heat balance models have led to experimental evaluation of the convective cooling effect. The dynamic transformer rating application has shown a possibility to decrease the size of the power transformer without shortcoming in component availability. / <p>QC 20180423</p> / Dynamic Rating for Wind Power

Esta tese procura demonstrar que a Energia é um Recurso de Poder relevante para compreender as relações entre os Estados, especificamente os padrões de hierarquização e distribuição de poder no Sistema Internacional. Neste sentido, Energia é entendida como um sistema que abrange desde a extração de recursos energéticos, os mecanismos de transformação e uso final, a capacidade de decisão e uso da infraestrutura energética e de pesquisa e desenvolvimento tecnológico. Para isso, esta tese está dividida em três capítulos, procurando estabelecer, primeiramente as relações entre Energia e Poder no campo teórico-conceitual, para em seguida analisar o papel do Centro de Decisão Energética na Estratégia de Segurança Energética das Grandes Potências. O segundo capítulo analisa a geopolítica do controle dos recursos energéticos, com foco nas disputas geopolíticas pelo petróleo e da evolução das tecnologias relacionadas ao uso de petróleo e eletricidade nos principais conflitos do século XX. Por fim, o terceiro capítulo é destinado à operacionalização de indicadores quantitativos e qualitativos relacionados à estratégia energética adotada por grandes potências como EUA e também, pelo conjunto dos países emergentes que inclui Brasil, Rússia, Índia e China. Considera-se que a Energia é uma variável decisiva para se analisar as mudanças distribuição de poder entre as grandes potências. Destarte, a capacidade de decisão referente ao uso de recursos energéticos é central para garantir a Soberania de um Estado. / This thesis proposes that Energy is an important variable for explaining power relations among States, specifically hierarchy and distribution of Power in the International System. In this sense, Energy is understood as a system that comprehends the extraction of energy resources, the mechanisms for processing and the end-use energy consumption, and the capability to decide on the use of energy infrastructure, on research and on technological energy development. To accomplish this objective, this thesis is divided into three chapters. The first chapter aims to establish the relationship between Energy and Power in the theoretical-conceptual level, and analyzes the role of the Energy Decision Center on the Energy Security Strategy of the Great Powers. The second chapter analyzes the geopolitical control of energy resources, focusing on geopolitical disputes over oil and the development of technologies related to the use of oil and electricity in the great wars of the twentieth century. Finally, the third chapter is dedicated to operationalize quantitative and qualitative indicators related to energy strategy adopted by great powers like the U.S., as well by the group of emerging powers that includes Brazil, Russia, India and China. This thesis concludes that Energy is a decisive variable to analyze changes in the distribution of power among the Great Powers. Therefore, the decision-making capacity on the subject of the use of energy resources is essential to ensure the sovereignty of any State.

Esta tese procura demonstrar que a Energia é um Recurso de Poder relevante para compreender as relações entre os Estados, especificamente os padrões de hierarquização e distribuição de poder no Sistema Internacional. Neste sentido, Energia é entendida como um sistema que abrange desde a extração de recursos energéticos, os mecanismos de transformação e uso final, a capacidade de decisão e uso da infraestrutura energética e de pesquisa e desenvolvimento tecnológico. Para isso, esta tese está dividida em três capítulos, procurando estabelecer, primeiramente as relações entre Energia e Poder no campo teórico-conceitual, para em seguida analisar o papel do Centro de Decisão Energética na Estratégia de Segurança Energética das Grandes Potências. O segundo capítulo analisa a geopolítica do controle dos recursos energéticos, com foco nas disputas geopolíticas pelo petróleo e da evolução das tecnologias relacionadas ao uso de petróleo e eletricidade nos principais conflitos do século XX. Por fim, o terceiro capítulo é destinado à operacionalização de indicadores quantitativos e qualitativos relacionados à estratégia energética adotada por grandes potências como EUA e também, pelo conjunto dos países emergentes que inclui Brasil, Rússia, Índia e China. Considera-se que a Energia é uma variável decisiva para se analisar as mudanças distribuição de poder entre as grandes potências. Destarte, a capacidade de decisão referente ao uso de recursos energéticos é central para garantir a Soberania de um Estado. / This thesis proposes that Energy is an important variable for explaining power relations among States, specifically hierarchy and distribution of Power in the International System. In this sense, Energy is understood as a system that comprehends the extraction of energy resources, the mechanisms for processing and the end-use energy consumption, and the capability to decide on the use of energy infrastructure, on research and on technological energy development. To accomplish this objective, this thesis is divided into three chapters. The first chapter aims to establish the relationship between Energy and Power in the theoretical-conceptual level, and analyzes the role of the Energy Decision Center on the Energy Security Strategy of the Great Powers. The second chapter analyzes the geopolitical control of energy resources, focusing on geopolitical disputes over oil and the development of technologies related to the use of oil and electricity in the great wars of the twentieth century. Finally, the third chapter is dedicated to operationalize quantitative and qualitative indicators related to energy strategy adopted by great powers like the U.S., as well by the group of emerging powers that includes Brazil, Russia, India and China. This thesis concludes that Energy is a decisive variable to analyze changes in the distribution of power among the Great Powers. Therefore, the decision-making capacity on the subject of the use of energy resources is essential to ensure the sovereignty of any State.

Esta tese procura demonstrar que a Energia é um Recurso de Poder relevante para compreender as relações entre os Estados, especificamente os padrões de hierarquização e distribuição de poder no Sistema Internacional. Neste sentido, Energia é entendida como um sistema que abrange desde a extração de recursos energéticos, os mecanismos de transformação e uso final, a capacidade de decisão e uso da infraestrutura energética e de pesquisa e desenvolvimento tecnológico. Para isso, esta tese está dividida em três capítulos, procurando estabelecer, primeiramente as relações entre Energia e Poder no campo teórico-conceitual, para em seguida analisar o papel do Centro de Decisão Energética na Estratégia de Segurança Energética das Grandes Potências. O segundo capítulo analisa a geopolítica do controle dos recursos energéticos, com foco nas disputas geopolíticas pelo petróleo e da evolução das tecnologias relacionadas ao uso de petróleo e eletricidade nos principais conflitos do século XX. Por fim, o terceiro capítulo é destinado à operacionalização de indicadores quantitativos e qualitativos relacionados à estratégia energética adotada por grandes potências como EUA e também, pelo conjunto dos países emergentes que inclui Brasil, Rússia, Índia e China. Considera-se que a Energia é uma variável decisiva para se analisar as mudanças distribuição de poder entre as grandes potências. Destarte, a capacidade de decisão referente ao uso de recursos energéticos é central para garantir a Soberania de um Estado. / This thesis proposes that Energy is an important variable for explaining power relations among States, specifically hierarchy and distribution of Power in the International System. In this sense, Energy is understood as a system that comprehends the extraction of energy resources, the mechanisms for processing and the end-use energy consumption, and the capability to decide on the use of energy infrastructure, on research and on technological energy development. To accomplish this objective, this thesis is divided into three chapters. The first chapter aims to establish the relationship between Energy and Power in the theoretical-conceptual level, and analyzes the role of the Energy Decision Center on the Energy Security Strategy of the Great Powers. The second chapter analyzes the geopolitical control of energy resources, focusing on geopolitical disputes over oil and the development of technologies related to the use of oil and electricity in the great wars of the twentieth century. Finally, the third chapter is dedicated to operationalize quantitative and qualitative indicators related to energy strategy adopted by great powers like the U.S., as well by the group of emerging powers that includes Brazil, Russia, India and China. This thesis concludes that Energy is a decisive variable to analyze changes in the distribution of power among the Great Powers. Therefore, the decision-making capacity on the subject of the use of energy resources is essential to ensure the sovereignty of any State.