Dissertations / Theses on the topic 'Energetical optimization'

Afin de réduire les émissions de polluants et de CO2 les constructeurs automobiles se tournent de plus en plus versdes solutions de chaîne de traction électrifiées. Cette électrification des véhicules augmente la complexité des systèmes à concevoir. Les outils MBSE basés sur une approche système peuvent être utilisés pour gérer cette complexité grandissante. Une optimisation globale nécessite de s’intéresser aux trois niveaux de conception suivants : architecture, composant et contrôle. L’objectif de cette thèse est de développer une méthode d’optimisation globale pour la conception de systèmes de refroidissement pour véhicules hybrides. A partir d’un jeu de composants et d’exigences systèmes à satisfaire, la méthode commence par générer automatiquement toutes les solutions possibles. La génération d’architectures est basée sur un concept d’arbre de décision. Chaque solution est ensuite optimisée d’un point de vue énergétique sous des contraintes hydrauliques, thermiques et d’intégration. Enfin, une optimisation multicritère permetd’aider les ingénieurs à prendre des décisions sur les choix de solution en phase amont de projet. L’application de la méthode globale d’optimisation de circuit de refroidissement pour véhicule HEV sur un projet existant chez Renault a montré que le système est porté par ses exigences. Une modification des exigences système est susceptible de modifier la solution d’architecture système optimale par rapport au cahier des charges
To reduce CO2 and pollutant emissions, automotive manufacturers tend to turn increasingly towards electrified powertrains solutions, such as Hybrid Vehicles (HEV). Model Based System engineering (MBSE) and computational tools are useful to support the development of HEV systems. Global optimization needs to investigate the following system design level: architecture, component and control. The aim of this thesis is to develop a global optimization framework to design cooling system for hybrid vehicles. The methodology starts from a set of component and system requirements to automatically generate all possible system architectures. The generation of solution is based on a concept of decision tree. An energentical optimisation under hydraulic, thermal and integration cosntraitns is done on each solution generated. Finally, amulticritetria optimization is used as decision making tool to support engineers on system archtiecture choices early in the development process. This framework has been applied on a Renault project. Results showed that the system is highly dependent on its requirements. Changing system requirements can potentially modify the optimal system architecture regarding the system specifications

La segmentation hiérarchique est une méthode pour produire des partitions qui représentent une même image de manière de moins en moins fine. En même temps, elle sert d'entrée à la recherche d'une partition optimale, qui combine des extraits des diverses partitions en divers endroits. Le traitement hiérarchique des images est un domaine émergent en vision par ordinateur, et en particulier dans la communauté qui étudie les images hyperspectrales et les SIG, du fait de son capacité à structurer des données hyper-dimensionnelles. Le chapitre 1 porte sur les deux concepts fondamentaux de tresse et de treillis énergétique. La tresse est une notion plus riche que celle de hiérarchie de partitions, en ce qu'elle incorpore, en plus, des partitions qui ne sont pas emboîtées les unes dans les autres, tout en s'appuyant globalement sur une hiérarchie. Le treillis énergétique est une structure mixte qui regroupe une tresse avec une énergie, et permet d'y définir des éléments maximaux et minimaux. Lorsqu'on se donne une énergie, trouver la partition formée de classes de la tresse (ou de la hiérarchie) qui minimise cette énergie est un problème insoluble, de par sa complexité combinatoriale. Nous donnons les deux conditions de h-croissance et de croissance d'échelle, qui garantissent l'existence, l'unicité et la monotonie des solutions, et conduisent à un algorithme qui les détermine en deux passes de lecture des données. Le chapitre 2 reste dans le cadre précédent, mais étudie plus spécifiquement l'optimisation sous contrainte. Il débouche sur trois généralisations du modèle Lagrangien. Le chapitre 3 applique l'optimisation par treillis énergétique au cas de figure où l'énergie est introduite par une « vérité terrain », c'est à dire par un jeu de dessins manuel, que les partitions optimales doivent serrer au plus près. Enfin, le chapitre 4 passe des treillis énergétiques à ceux des courbes de Jordan dans le plan euclidien, qui définissent un modèle continu de segmentations hiérarchiques. Il permet entre autres de composer les hiérarchies avec diverses fonctions numériques
Hierarchical segmentation has been a model which both identifies with the construct of extracting a tree structured model of the image, while also interpreting it as an optimization problem of the optimal scale selection. Hierarchical processing is an emerging field of problems in computer vision and hyper-spectral image processing community, on account of its ability to structure high-dimensional data. Chapter 1 discusses two important concepts of Braids and Energetic lattices. Braids of partitions is a richer hierarchical partition model that provides multiple locally non-nested partitioning, while being globally a hierarchical partitioning of the space. The problem of optimization on hierarchies and further braids are non-tractable due the combinatorial nature of the problem. We provide conditions, of h-increasingness, scale-increasingness on the energy defined on partitions, to extract unique and monotonically ordered minimal partitions. Furthermore these conditions are found to be coherent with the Braid structure to perform constrained optimization on hierarchies, and more generally Braids. Chapter 2 demonstrates the Energetic lattice, and how it generalizes the Lagrangian formulation of the constrained optimization problem on hierarchies. Finally in Chapter 3 we apply the method of optimization using energetic lattices to the problem of extraction of segmentations from a hierarchy, that are proximal to a ground truth set. Chapter 4 we show how one moves from the energetic lattice on hierarchies and braids, to a numerical lattice of Jordan Curves which define a continous model of hierarchical segmentation. This model enables also to compose different functions and hierarchies

This thesis discusses the operational coordination of electrical appliances and devices in a smart home. At present, the diminishing volume of fossil fuels and the increasing pressure to use renewable sources of energy necessitate the integration of such volatile sources into electrical grids. This process, however, results in higher energy costs, and the consumers are thus more willing to change their behaviour to either reduce the expenses or maintain them at a reasonable level. One of the relatively few customer-oriented options to optimise energy costs consists in the demand – response principle, which utilises external information to minimise energy consumption during high price periods. Assuming the constantly changing conditions in electrical grids, and thus also the varying demands, it is vital to provide for automatic optimisation excluding the need of user intervention. The thesis presents a method which, after being implemented into the control member, will facilitate the optimal use of appliances and devices within a smart home. As the behaviour considered optimal from the perspective of demand - response is often inconsistent with the consumer‘s requirements for comfortable use of the appliances, the proposed technique offers a compromise through enabling the consumer to select the appropriate strategy. Five universal optimisation models are designed within the thesis; these models facilitate description of common home appliances and local electricity sources. The core of the method lies in formulating and optimising a mixed integer quadratic problem (MIQP). The optimisation task yields an operational schedule for the individual appliances, and this scheme considers the energy costs, the working cycle of the appliance, the user’s demands, the system restrictions and/or other input data. Furthermore, the author extends the above-discussed general technique, enabling it to adopt robust behaviour. The method then secures the preset strategy even during a marked change of the input conditions, and its robustness is a viable precondition for the overall applicability of the technique in the real control member.

The main aim of this thesis is to create a sequence of mathematical optimization models with different levels of complexity for the efficient management and waste energy utilization. Stochastic programming approach was utilized to deal with random demand and uncertain heating values. Hence, more applicable model of the waste-to-energy plant has been developed. As the next step, the model is enhanced by heating plant extension. Computations are realized for real-world data and optimal solution is found by using GAMS implementation.

L’objectiu d’aquesta tesis és desenvolupar eines sistemàtiques de suport per la presa de decisions basades en mètodes matemàtics pel disseny òptim d’edificis amb mínim cost i mínim impacte ambiental. Avui en dia la societat és cada vegada més conscient de la importància que té respectar el medi ambient. Com a resultat, les autoritats i moltes empreses i consumidors estan interessats en productes econòmicament eficients però també respectuosos amb el medi ambient. En aquest context l’eficiència energètica hi juga un paper molt important. L’aïllament d’edificis és particularment interessant, ja que fa disminuir el consum d’energia i, conseqüentment, permet reduir també l’impacte ambiental. El problema general que pretenem solucionar en aquesta tesis és el disseny d’edificis ambientalment respectuosos amb el mínim cost econòmic, centrant-nos en l’optimització de l’aïllament tèrmic exterior. Per tal de demostrar les possibilitats de les nostres eines, considerem un cas d’estudi: Una casa tipus cubicle localitzada a la regió de Lleida. No obstant les nostres metodologies són suficientment generals per treballar amb diferents models d’edifici, variables de decisió i funcions objectiu. Els nostres mètodes s’han desenvolupat amb la intenció d’ajudar als agents involucrats en el disseny d’edificis.
El objetivo de esta tesis es desarrollar herramientas sistemáticas de soporte para la toma de decisiones basadas en métodos matemáticos para el diseño óptimo de edificios con mínimo coste y mínimo impacto ambiental. Hoy en día la sociedad es cada vez más consciente de la importancia que tiene respetar el medio ambiente. Como resultado, las autoridades y muchas empresas y consumidores están interesados en productos económicamente eficientes pero también respetuosos con el medio ambiente. En este contexto la eficiencia energética juega un papel muy importante. El aislamiento de edificios es particularmente interesante, ya que hace disminuir el consumo de energía y, consecuentemente, permite reducir también el impacto ambiental. El problema general que pretendemos solucionar en esta tesis es el diseño de edificios ambientalmente respetuosos con el mínimo coste económico, centrándonos en la optimización del aislamiento térmico exterior. Para demostrar las posibilidades de nuestras herramientas, consideramos un caso de estudio: Una casa tipo cubículo localizada en la región de Lleida. No obstatnte nuestras metodologías son suficientemente generales para trabajar con diferentes modelos de edificio, variables de decisión y funciones objetivo. Nuestros métodos se han desarrollado con la intención de ayudar a los agentes involucrados en el diseño de edificios.
The goal of this thesis is to provide systematic mathematical decision-support tools for the design of optimal buildings with minimum cost and minimum environmental impact. Nowadays the society is becoming more aware of the importance of being environmentally conscious. As a result, the authorities and many companies and consumers seek for products that are cost efficient but also environmentally friendly. Here energy efficiency plays an important role. Building insulation is particularly appealing, since it decreases the energy demand, thereby leading to significant environmental savings. The general problem we aim to solve in this thesis is the design of environmentally friendly buildings with the lowest possible cost focusing on the optimization of the external thermal insulation. To illustrate the capabilities of our approaches, we consider a case study: A house-like cubicle located in the Lleida region. However our methodology is general enough to work with different building models, decision variables and objective functions. Our methods are intended to assist decision-makers in the design of buildings.

Contain of master´s thesis is a energy assessment of multifunctional building in Komňátka. The theoretical part deals with the analysis of legislativ documents, current technical solution and practical application to the specified building. In the practical part thesis focus on experimental determination of the heat transfer coefficient using thermography.

This masters thesis is dealing with energetic evaluation of selected municipal WWTP – WWTP Polička. First chapter, introduction explains basic terms and goals of thesis. Second chapter explains energy audit, energy audit process its scope and contents. Third chapter deals with assesing life cycle using LCA (life cycle assesment). Fourth chapter deal with energy consumption at WWTP in Czech Republic as well as in the world. Fifth chapter describes technology of WWTP Polička and its fundamental objects. Sixth chapter is assesment of WWTP Polička from hydraulic point of view and assesment of selected machinery. Further there is summation of capital and operational costs followed by capital investment return.

The research part of the diploma thesis is focused on an issue of energy consumption in sludge treatment at wastewater treatment plants divided by the number of population equivalent. The aim of the practical part is to set indicators and propose evaluative criteria concerning energy performance of urban wastewater treatment plants. The verification of proposed criteria and energetic analysis result from data of the wastewater treatment plant in Novy Jicin.

The aim of this Master Thesis is to study numerically the aerodynamic performance of two small examples of horizontal axis domestic wind turbines: a conventional Savonius rotor, designed and built by a group of students of the Polytech of Tours (France), and its optimization, a helical Savonius rotor. In the first research project, the exploration is conducted even experimentally, testing the turbine in a wind tunnel present in the Polytech. The numerical investigation is carried out by the use of a software based on Computational Fluid Dynamics named Star CCM+, which helps studying the main fluid dynamics aspects as flow velocity, pressure and coefficients of performance. The second project consists in a helical Savonius rotor: according to the literature, the helical shape, comparing with the conventional Savonius rotor, usually shows better performances. After the 3D design on Catia, the turbine was printed using the 3D printer, on a reduced scale. CFD simulations allow to study the fluid dynamic features. Afterwards, thanks to a comparison between the two Savonius models, the performance enhancement of the new one is shown, together with a practical understanding gained of the parameters influencing aerodynamics the most. By means of the simulations, the helical rotor presents a power coefficient of 10%, which is better than the one of the conventional rotor, found at 7% for the same Tip Speed Ratio. Consequently, even the power produced by the new turbine, resulted to be better than the conventional windmill.

PhD thesis deals with the application of the simulation and optimization methods in the waste-to-energy field. An introduction describes the current state of the waste management in the EU with the focus on the Czech Republic. In the following chapter the evaluation criteria for investment intentions and the basic principles of stochastic programming are discussed. The core of the work lays in the mathematical models for the planning and operation of the process plants as well as in the mathematical models for the waste collection. The transportation problem involves all considered technological elements and therefore it is possible to simulate the waste streams between the producers and processors. This approach is demonstrated with five case studies. In the first three studies the calculations for the potential investor are presented. The main outcome of these case studies is the determination of the level of attractiveness of investment and the identification the greatest risks. Another case study is devoted to an analysis with the focus on perspective of government policies and in the last case study the issue of the waste management is analyzed in detail from the perspective of the waste producers. Developed computational tools are flexible and can be further developed and adapted based on the objectives of the specific tasks.

The aim of the diploma thesis is to design austerity measures of an apartment building in the form of an energy card. The theoretical part deals with heat pumps. The computational part solves the evaluation of the current state of the building, the proposal of two variants, the assessment in terms of energy and economic and recommendations of the selected variant. There is also an experimental measurement specializing in thermovision imaging. The project contains energy certificates of individual states of the solved object.

In a world focused on the need to produce energy for a growing population, while reducing atmospheric emissions of carbon dioxide, organic Rankine cycles represent a solution to fulfil this goal. This study focuses on the design and optimization of axial-flow turbines for organic Rankine cycles. From the turbine designer point of view, most of this fluids exhibit some peculiar characteristics, such as small enthalpy drop, low speed of sound, large expansion ratio. A computational model for the prediction of axial-flow turbine performance is developed and validated against experimental data. The model allows to calculate turbine performance within a range of accuracy of ±3%. The design procedure is coupled with an optimization process, performed using a genetic algorithm where the turbine total-to-static efficiency represents the objective function. The computational model is integrated in a wider analysis of thermodynamic cycle units, by providing the turbine optimal design. First, the calculation routine is applied in the context of the Draugen offshore platform, where three heat recovery systems are compared. The turbine performance is investigated for three competing bottoming cycles: organic Rankine cycle (operating cyclopentane), steam Rankine cycle and air bottoming cycle. Findings indicate the air turbine as the most efficient solution (total-to-static efficiency = 0.89), while the cyclopentane turbine results as the most flexible and compact technology (2.45 ton/MW and 0.63 m3/MW). Furthermore, the study shows that, for organic and steam Rankine cycles, the optimal design configurations for the expanders do not coincide with those of the thermodynamic cycles. This suggests the possibility to obtain a more accurate analysis by including the computational model in the simulations of the thermodynamic cycles. Afterwards, the performance analysis is carried out by comparing three organic fluids: cyclopentane, MDM and R245fa. Results suggest MDM as the most effective fluid from the turbine performance viewpoint (total-to-total efficiency = 0.89). On the other hand, cyclopentane guarantees a greater net power output of the organic Rankine cycle (P = 5.35 MW), while R245fa represents the most compact solution (1.63 ton/MW and 0.20 m3/MW). Finally, the influence of the composition of an isopentane/isobutane mixture on both the thermodynamic cycle performance and the expander isentropic efficiency is investigated. Findings show how the mixture composition affects the turbine efficiency and so the cycle performance. Moreover, the analysis demonstrates that the use of binary mixtures leads to an enhancement of the thermodynamic cycle performance.

The work deals with the measurement and management in power. Provides an introduction to the problems of remote meter reading, management, and describes the current situation in the field of modern technologies Smart metering and Smart grids. It also analyzed the issue of collection of networks and data collection from a large number of meters over a wide area. For the purpose of data transmission are described GPRS, PLC, DSL, ... Further, there are given options to streamline communication. This area is used hierarchical aggregation. Using k-means algorithm is a program designed to calculate the number of concentrators and their location in the group of meters. The finished program is written in Java. It has a graphical interface and shows how the calculation is conducted. To verify the results of the optimization program is given simulation model in OPNET Modeler tool. Audited results are described in the conclusion and can deduce that using the optimization program is to streamline communications.

The performance of microchannel heat exchangers was assessed in gas-to-liquid applications in the order of several tens of kWth . The technology is suitable for exhaust heat recovery systems based on organic Rankine cycle. In order to design a light and compact microchannel heat exchanger, an optimization process is developed. The model employed in the procedure is validated through computational fluid-dynamics analysis with commercial software. It is shown that conjugate effects have a significant impact on the heat transfer performance of the device.

The diploma thesis with research of efficiency of renewable and low-potential energy sources of buildings. It is available on numerical simulations for sharing office and heating and cooling system buildings in DesignBuilder. There are various energy sources and ways of controlling heating and cooling. The results are evaluated in terms of time, after the expected compromises in the building, in terms of energy consumption and its price.

The use of light hydrocarbons is desirable in order to mitigate the human impact on the environment. Besides, this strategy is a forerunner solution for the implementation of a hydrogen economy in the long term. Cryogenic conditions represent an attractive option to make the use of these fuels more sustainable. Since the bottleneck for their large-scale adoption is represented by safety aspects, an emergency auto-thermal burner was designed. This safety system has the purpose to dispose of the content of a tank truck, in order to avoid the loss of containment and the accidental release of LNG or LH2. The disposal of the fuel includes its vaporization, the heating of the vapor phase up to a temperature suitable for combustion, the mixing with ambient air, and the combustion. The most important technical requirements are the duration of the discharge process and the portability of this device. The temperature of flue gases was estimated through numerical methods. Then, inner and outer heat transfer coefficients were determined for each coiled-tube heat exchanger, and their surface was calculated, solving the equation of energy balance along the pipe. Finally, the nozzle was designed in order to slow down the gaseous fuel slightly upstream of the burner. Two variants are proposed for the emergency burner for LNG: one with separate reboiler and another with evaporation in tube. While the former option is suitable for stationary applications, the latter is easy to transport, assemble, and put into operation, since it is lightweight and does not require any heat transfer fluid. The emergency burner for LH2 was designed with evaporation in tube only. The para-to-ortho conversion was considered since it results from the increase in hydrogen temperature. The enthalpy of this endothermic reaction represents an additional energy request. If the decrease of para-hydrogen fraction along the pipe was neglected, the length of the superheater would be significantly underestimated.

Orientador: Secundino Soares Filho
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: O planejamento da operação energética do Sistema Interligado Nacional (SIN) é uma tarefa complexa realizada por meio de uma cadeia de modelos de médio, curto e curtíssimo prazo acoplados entre si, cada um com considerações pertinentes à etapa que aborda. A proposta deste trabalho é apresentar uma alternativa para o planejamento da operação energética de médio prazo. Foi desenvolvida uma metodologia baseada em modelo de controle preditivo, abordando os aspectos estocásticos do problema de forma implícita pela utilização de valores esperados das vazões, e fazendo uso de um modelo determinístico de otimização a usinas individualizadas, que possibilita uma representação mais precisa do sistema hidrotérmico. A análise de desempenho é feita através de simulações da operação, considerando os parques hidrelétrico e termelétrico que compõem o SIN, com restrições operativas reais, em configuração dinâmica, com plano de expansão e a possibilidade de intercâmbio e importação de mercados vizinhos. Os resultados são comparados aos fornecidos pela metodologia em vigor no setor elétrico brasileiro, notadamente o modelo NEWAVE, que determina as decisões de geração por subsistema, e o modelo Suishi-O, que as desagrega por usinas individualizadas
Abstract: The long term hydrothermal scheduling of the Brazilian Integrated System (SIN) is a complex task solved by a chain of long, medium and short term coupled models, each one with considerations pertinent to the stage of operation that it deals with. The proposal of this work is to present an alternative for the long term hydrothermal scheduling. A methodology based on model predictive control was developed, implicitly handling stochastic aspects of the problem by the use of inflows expected values, and making use of a deterministic optimization model to obtain the optimal dispatch for individualized plants, what makes possible a more accurate representation of the hydrothermal system. The performance analysis is made through simulations of the operation, taking into consideration all the hydro and thermal plants that compose the SIN, with real operative constraints, in dynamic configuration, with its expansion plan and the possibility of interchange and importation from neighboring markets. The results are compared with those provided by the approach actually in use by the Brazilian electric sector, specifically the NEWAVE model, which defines the generation decisions for the subsystems, and the Suishi-O model, that disaggregates them for the individualized plants
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica

Nel quadro del progetto SaLüΗ! verrà sviluppato un sistema di ventilazione meccanica con recupero di calore combinato ad una micro pompa di calore. La perdita di carico all’interno del sistema, l’omogeneità del flusso d’aria attraverso gli scambiatori di calore e le emissioni sonore devono essere ottimizzati. In questo lavoro di tesi viene sviluppato un modello CFD preliminare, con particolare riferimento alla condotta di mandata, nella quale sono alloggiati il compressore ed il condensatore della pompa di calore. A questo scopo, verrà utilizzato il software commerciale COMSOL® Multiphysics®. Si assume un fluido incomprimibile e moto isotermico. Il fine è quello di analizzare e comparare la distribuzione del campo di velocità in ingresso al condensatore, per due configurazioni convenzionali e due configurazioni a V. Tre diversi modelli dello scambiatore di calore sono calibrati con dati sperimentali, ricavati dalle librerie di EES – Engineering Equation Solver. I modelli di turbolenza a due equazioni disponibili in COMSOL® sono confrontati con le misure effettuate da Lourenco e Shih per un cilindro circolare a Re = 3900. Un coefficiente di omogeneità basato sulla deviazione standard è introdotto e calcolato per la componente di velocità normale alla superficie di ingresso del condensatore. I risultati mostrano che un sistema molto compatto comporta una maldistribuzione del flusso d’aria in ingresso allo scambiatore di calore, che può essere ridotta leggermente adottando una configurazione a V.

Orientador: Secundino Soares Filho
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Este trabalho apresenta uma política para a operação energética do Sistema Nacional (SIN), baseada na representação individualizada das usinas hidrelétricas e termelétricas, na representação detalhada das características de operação dessas usinas, e na representação indireta da estocasticidade das vazões através demodelo de previsão. Essas características diferem a política operativa proposta daquela em vigor no setor elétrico brasileiro, que se baseia na modelagem equivalente de sistemas hidrotérmicos interligados. Diversos estudos de caso são apresentados com o intuito de avaliar o desempenho dessa polÂ'ıtica, desde o caso de sistemas hidrotérmicos simples com uma única usina até o caso completo do SIN sob condições reais. Para esse último caso, um procedimento de ajuste da operação foi implementado para assegurar o atendimento do mercado com as restrições de intercâmbio entre os subsistemas. Análises de sensibilidade foram realizadas em relação a restrições de intercâmbio, inflexibilidade das usinas termelétricas, a importância de algumas usinas hidrelétricas e mercado
Abstract: This work presents an operational policy for the mid term hydrothermal scheduling of the Brazilian Interconnected Power System (BIPS) based on the individual representation of the hydro and thermo power plants, the detailed representation of the plantsâ?¿ features and the indirect representation of the inflow stochasticity through a forecasting model. These characteristics differs the operational policy which is in use nowadays in BIPS, which is based on four interconnected subsystems represented by composite reservoirs. Several case studies are presented to evaluate the performance of the operational policy, from the simple case with a single hydro plant system to the complete case of the whole BIPS under real conditions. For this last case an operational adjustment procedure was implemented to assure the market attendance considering interchange constraints between the subsystems. Sensitivity analyses have been done with respected to interchange, minimum thermal generation, market, importance of hydro plants and system dimension
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica

Ce travail essaie d'aborder la problématique de la transition énergétique sous un angle assez particulier afin de soulever la complexité de cette transition et le fait qu'on est encore relativement loin de traiter cette question d'une manière convenable et convaincante. Après avoir discuté cette problématique dans les deux premiers chapitres, en se basant sur la littérature déjà existante, deux autres modèles ont été proposés afin de contribuer modestement à cette littérature. Ces deux modèles sont de deux familles différentes, notamment TETM et EnvETM2, qui ont, chacun, des particularités propres , et donnent, en général, des résultats assez divergents.On déduit des résultats du premier modèle que le développement des énergies renouvelables ne doit pas dépasser un certain niveau, et que les politiques basées sur les prix de l'énergie (taxes, subventions, ...) seront plus efficaces pour accélérer la transition énergétique. La transition énergétique ne pourra passer avec le même rythme dans tous les secteurs, ce qui fait que les choix politiques doivent être très précis pour viser les bons secteurs et territoires, afin de mener une transition optimale.Le deuxième modèle a pour objectif la généralisation du modèle CMM afin d'explorer de nouvelles politiques pour lutter contre les problèmes environnementaux, causés par l'utilisation massive des ressources énergétiques fossiles, sources des gaz à effet de serre. On peut résumer les résultats de ce modèle en déduisant que l'énergie renouvelable doit être produite tout le temps, même avec un prix de l'énergie inférieur à son coût marginal. Ce qui implique que les énergies renouvelables doivent être subventionnées, tant qu'elles restent non-compétitives. L' utilisation des énergies renouvelables n'est pas forcement une solution suffisante pour lutter contre l'émission de gaz à effet de serre ; dans certains cas on doit diminuer, en même temps, l'utilisation de cette énergie propre
This work tries to approach the problem of the energy transition under a rather particular angle to raise the complexity of this transition and the fact whom we are still relatively far from handling this question in a suitable and convincing way. By discuss this problem in the first two chapters, basing on the already existing literature ; two other models were proposed to contribute modestly to this literature. These two models belong to two different families, in particular TETM and EnvETM2 who have, each, peculiarities appropriate to him, and give, generaly, rather divergent results.We deduce from results of the first model that the development of the renewable energies does not have to exceed certain level, and that the policies based on energy prices (taxes, subsidy, ...) will be more effective to accelerate the energy transition. The energy transition will not can pass with the same rhythm in all sectors, what makes that political choices must be very precise to choose the rignts sectors ans territories, to lead an optimal transition.The second model, has for objective the generalization of the model of CMM1 to explore new policies to fight against the environmental problems, caused by the massive use of the fossil energy resources, sources of GHG (greenhouse gas emissions). We can summarize the results of this model by deducing that the renewable energy must be produced over time, even with an energy price lower than its marginal cost. This implies that the renewable energies have to subsidized, as long as they remain non-competitive. The use of the renewable energies is not sufficient solution to fight against GHG emissions, in certain case we have to abate as we use ReE

The thesis deals with the environmental assessment of buildings, concrete objects Letní lázně at Karlova Studánka. The first part describes the issue and legislation. There is also described a method of experimental measurement and methods of moisture measurement. The second part deals with the analysis of the specified object, description of selected renewable sources and description of possible modifications of the object. The third part is devoted to modeling and simulation of the specified object in DesignBuilder. Using the model were created various simulations with various modifications in order to reduce energy intensity of the object. Results were then evaluated and compared.

The doctoral thesis pays attention to the system approach to the nonstationary computational modelling of heat transfer for energy saving buildings. The created computational tool supports the optimization of selected design parameters.

Questa tesi tratta della progettazione dei parametri e dell'ottimizzazione del modello di consumo energetico degli edifici sulla base di immagini ad infrarossi. I contenuti della ricerca si possono riassumere come segue: 1. Definizione ed implementazione di un nuovo modello semplificato di consumo di energia. In base alle conoscenze teoriche esistenti, il modello complesso di consumo energetico viene semplificato come funzione di correlazione con il consumo di energia delle pareti e con tutti gli altri consumi energetici. 2. Progettazione dei parametri del modello. Prendendo in considerazione la quantità dei dati, i requisiti di velocità di calcolo, nonché l'analisi empirica esistente del consumo di energia, viene selezionato il nonlinear least square method per risolvere il problema di progettazione del parametro. 3. Ottimizzazione del valore del parametro nel modello di consumo energetico. Il problema di ottimizzazione del modello di edificio è considerato come “knapsack problem” e risolto dalla programmazione dinamica. 4. Progettazione del sistema di acquisizione dati per il modello di consumo energetico. Le temperature delle pareti sono ottenute dalle telecamere ad infrarossi FLIR Vue Pro e FLIR One. Considerando le difficoltà nel misurare la temperatura delle pareti esterne del grattacielo, si prevede di collegare la telecamera a infrarossi al velivolo SAGA D600 come piattaforma di test. 5. Proposizione di un modello confermato in base a test sul campo. La sperimentazioneè suddivisa in due parti. La prima parte ha l’obiettivo di stimare il consumo di energia di un closed foam box per verificare il modello di parete. La seconda calcola il consumo energetico di un edificio situato nel sud-est di Shanghai utilizzandoil sistema di acquisizione dati sviluppatodalla tesi. E’ stato così dimostrato che il modello propostoè in grado di simulare l'andamento del consumo energetico dell'edificio e che i valori dei parametri sono ragionevoli.

Human efforts to increase their comfort rise in density of population in congested city areas, rapid growth of traffic and electric smog created due to constantly transforming communication technologies all resulted in an increase of stress in the immediate human environment. All of this, along with frequent reports about changes in global climate, gradually contributes to an alteration of thinking of the whole society, which is forced to face the consequences of economic damages caused by climatic changes. If we want to tenably assert adequate economic and social living conditions, we have to approach the natural environment in a more profound way. In accordance with the trend of substantional development for the purpose of enhancement of the quality of the living environment in the field of building industry, it is logical to concentrate on buildings, which are conceptually focused on saving of the energy. That is on energy-efficient houses. Pathway to sustainable building is not based on discovering one or several multipurpose technological solutions, but on usage of new designing principles, new materials and methods of processing them as well as new techniques of construction. For an effective creation of a building concept it is essential to have that kind of device which quickly responds to changes performed on a design, enables an easier work on variants and produces the most accurate results. Consistent application of energy optimizing methods is necessary particularly for designs of energy saving houses. Beginning efficient building design is the most “abstract factor of concept linked with very uncertain inputs,” because a lot of parameters in that moment is still unknown. Many mutually connected factors are invoked during designing passive house e.g. trajectory of the sun and the shielding effect of the surroundings, the aspect of sunlight and interior lighting, power quality construction, etc. Currently, the architect has no choice, he can use only well-known precepts, such as large windows are facing the South not the North. Unfortunately this "empirical formula" for the design of a real passive house is not enough. And yet the first draft of the house is most affected by not only its shape, form, but user´s comfortable, cost, feasibility and future energy behavior of buildings and related operating costs of the house too. It is obvious that this stage should not be underestimated, because “minor variation of the initial inputs greatly influence the outcomes.” With this reasoning, the work focuses on early stage design decision, i.e. the architectural concept of a passive house (an idea, vision). Therefore the aim of this work is to simplify the issue into understandable form, i.e. the creation of relatively simple and illustrative sketches, which generalize the issue satisfactorily, show the individual parameters (glazing, shading, shape, size, etc.) and change need of heat for heating passive house. The results of the work will be useful when the architect picks up the pencil and starts to think about his future house. At this point, he will have on hand sketches, which give him an idea and streamline his further design. Therefore the main goal is to create new outcomes and identify energy behaviour of buildings with a computational tool. This research works with virtual idealized mathematical model in the software PHPP 2007 CZ and uses "phenomenon" of parametric equations and sensitivity analysis.

The United Nations (UN) project "Sustainable energy for all" sets three ambitious objectives to favor a sustainable development and to limit climate change: - Universal access to modern energy services. Electricity is currently not available for 1.3 billion people and the global energy demand is expected to grow of about 35% within 2040, due to the increasing world population and the expanding economies - Double the global rate of improvement in energy efficiency - Double the share of renewable energy sources (RESs) in the global energy mix In addition, according to the climate scenario assessed in the fifth assessment report (AR5) of the International Panel on Climate Change (IPCC), the prevention of undesirable climate effects requires a 40-70% reduction of greenhouse gas (GHG) emissions, compared with 2010 levels, by mid-century, and to near-zero by the end of this century (IPCC, 2014). The achievement of such objectives requires and encourages the spread of RESs in the global energy mix, gradually replacing depleting and polluting energy sources based on fossil fuels, which still have the main incidence on the energy sector. RESs already play a major role in several countries, due to the technological development and the increasing market competitiveness, and the world renewable power capacity reached 22.1% in 2013, showing an increasing trend in 2014 (REN, 2014). However, supporting policies, robust investments from the private sector and efforts from the scientific community are still crucial to demonstrate the technical and economic sustainability and effectiveness of RESs, helping their large-scale diffusion. Starting from such a background, this Ph.D dissertation focuses on the study, design and development of methods and tools for the optimization and enhancement of renewable energy technologies and their effective integration with energy storage solutions and traditional energy sources powered by fossil fuels (hybrid energy systems). The analysis of the major literature and the different scenarios and perspectives of RESs in the national and international contexts have shown that their economic sustainability, and then their diffusion, is closely connected to a number of technical, economic/financial and geographical parameters. Such parameters are the input of the analytic models developed for the techno-economic design of photovoltaic (PV) plants and small wind turbines (SWTs) and applied to the economic feasibility study, through multi-scenario analysis, of such systems in some of the main European Union (EU) Countries. Among the obtained results, the self-consumption of the produced energy plays a crucial role in the economic viability of SWTs and PV plants and, particularly, after the partial or total cut of incentives and uncertainties related to supporting policies within the EU context. The study of the energy demand profile of a specific user and the adoption of battery energy storage (BES) systems have been identified as effective strategies to increase the energy self-consumption contribution. Such aspects have led to the development of an analytic model for the techno-economic design of a grid connected hybrid energy system (HES), integrating a PV plant and a BES system (grid connected PV-BES HES). The economic profitability of the grid connected PV-BES HES, evaluated for a real case study, is comparable with PV plants without storage in case of a significant gap between the cost of energy purchased from the grid and the price of energy sold to the grid, but high BES system costs due to the initial investment and the maintenance activities and the eventual presence of incentives for the energy sold to the grid can make the investment not particularly attractive. Thus, the focus has shifted to the techno-economic analysis of off-grid HES to meet the energy demand of users in remote areas. In this context, BES systems have a significant role in the operation and management of the system, in addition to the storage of exceeding energy produced by the intermittent and variable RESs. The analysis has also been strengthened by an industrial application with the aim to configure, test and install two off-grid HESs to meet the energy demand of a remote village and a telecommunication system. In parallel, two experimental activities in the context of solar concentrating technology, a promising and not fully developed technology, have been carried out. The former activity deals with the design, development and field test of a Fresnel lens pilot-scale solar concentrating prototype for the PV energy distributed generation, through multi-junction solar cells, and the parallel low temperature heat recovery (micro-cogeneration CPV/T system). The latter activity deals with the development of a low cost thermal energy (TES) storage prototype for concentrating solar power (CSP) plants. TES systems show a great potential in the CSP plants profitability since they can overcome the intermittent nature of sunlight and increase the capacity factor of the solar thermal power plant. Concluding, the present Ph.D dissertation describes effective methods and tools for the optimization and enhancement of RESs. The obtained results, showing their critical issues and potential, aim to contribute to their diffusion and favor a sustainable development
Il progetto delle Nazioni Unite "Sustainable energy for all" ha fissato tre obiettivi ambiziosi per favorire uno sviluppo sostenibile e limitare l'impatto del cambiamento climatico: - Accesso universale a moderni servizi elettrici. Tali servizi sono attualmente indisponibili per circa 1.3 miliardi di persone ed è previsto un aumento del 40% della domanda globale di energia elettrica entro il 2040, a causa dell'incremento della popolazione mondiale e delle economie in crescita nei paesi in via di sviluppo - Raddoppio del tasso globale di miglioramento dell'efficienza energetica - Raddoppio del contributo di fonti di tipo rinnovabile nel mix energetico globale Inoltre, lo scenario climatico proposto nel "fifth assessment report (AR5)" redatto da "International Panel on Climate Change (IPCC)" stabilisce la necessità di ridurre l'emissione di gas ad effetto serra del 40-70%, rispetto ai valori registrati nel 2010, entro il 2050 ed eliminarli in modo quasi definitivo entro la fine del secolo con lo scopo di evitare effetti climatici indesiderati. Il raggiungimento di tali obiettivi richiede e incoraggia la diffusione di fonti energetiche rinnovabili (FER) all'interno del mix energetico globale, rimpiazzando gradualmente le fonti di energia convenzionali basate su combustibili fossili, inquinanti e in via di esaurimento, che hanno ancora l'incidenza principale nel settore energetico. A seguito nel loro sviluppo tecnologico e la crescente competitività nel mercato, le FER rivestono già un ruolo fondamentale nel mix energetico di numerose Nazioni ricoprendo il 22.1% del fabbisogno globale di energia nel 2013 e mostrando un andamento in rialzo nel 2014 (REN, 2014). Tuttavia, sono ancora cruciali politiche di supporto, ingenti investimenti privati e contributi della comunità scientifica per dimostrare l'efficacia e la sostenibilità tecnica ed economica delle FER e favorire, quindi, una loro diffusione in larga scala. In questo contesto, la seguente tesi di dottorato è rivolta allo studio, progettazione e sviluppo di metodi e strumenti per l'ottimizzazione e la valorizzazione di tecnologie energetiche rinnovabili e la loro integrazione efficace con fonti di produzione di energia convenzionali alimentate da combustibili fossili e sistemi di accumulo di energia (Sistemi energetici di tipo ibrido). I contributi scientifici disponibili in letteratura e l'analisi dei diversi scenari e delle prospettive delle FER nei vari contesti nazionali ed internazionali hanno dimostrato che la loro sostenibilità economica, e quindi la loro diffusione, è strettamente legata ad una serie di parametri tecnici, economico / finanziari e geografici. Tali parametri sono stati impiegati come input in due modelli analitici sviluppati per la progettazione tecnico-economica di impianti fotovoltaici (FV) e micro turbine eoliche e applicati per lo studio della loro fattibilità economica, attraverso analisi multi-scenario, in alcuni dei maggiori Paesi Europei. I risultati ottenuti hanno mostrato come l'autoconsumo dell'energia prodotta rivesta un ruolo fondamentale nella redditività economica dei citati impianti ed, in particolare, a seguito del taglio parziale o totale dei sistemi di incentivazione e l'incertezza attorno alle politiche di supporto all'interno del panorama Europeo. Lo studio specifico del profilo di domanda elettrica delle utenze e l'impiego di sistemi di accumulo di energia sono stati identificati come strategie efficaci al fine di incrementare la quota di autoconsumo. Tali considerazioni hanno portato allo sviluppo di un modello analitico utile alla progettazione tecnico-economica un sistema energetico ibrido connesso alla rete Nazionale integrante un impianto FV e un sistema di accumulo a batterie. La redditività del sistema, valutata su un caso reale, risulta comparabile a un impianto fotovoltaico privo di batterie in caso di un gap significativo tra il costo dell'energia elettrica acquistata dalla rete e il prezzo di vendita dell'energia elettrica ceduta in rete. Tuttavia, gli elevati costi dovuti all'acquisto iniziale e alle attività di manutenzione, e l'eventuale incentivazione sulla vendita dell'energia in rete, non rendono l'investimento particolarmente attrattivo per impianti connessi alla rete. L'attenzione si è quindi rivolta all'analisi tecnico-economica di sistemi energetici ibridi non connessi alla rete, comunemente definiti in isola o off-grid, per soddisfare il fabbisogno energetico di utenti in area remote e quindi prive di allaccio a una rete elettrica. In tali sistemi, i sistemi di accumulo a batterie, oltre alla capacità di accumulo dell'energia prodotta in eccesso variabili e intermittenti FER, hanno funzioni fondamentali nella gestione del sistema stesso. L'attività è stata anche rafforzata da un'applicazione industriale per la configurazione, test e installazione di due sistemi energetici ibridi in isola impiegati per soddisfare il fabbisogno energetico di un villaggio e di un sistema di telecomunicazione situati in aree remote. In parallelo, sono state svolte due attività sperimentali applicate alla promettente, ma non ancora completamente sviluppata a livello industriale, tecnologia solare a concentrazione. La prima attività riguarda la progettazione, sviluppo e test sperimentali di un prototipo in scala ridotta di concentratore solare a lenti di Fresnel per la produzione distribuita di energia elettrica, mediante l'uso di celle fotovoltaiche multi giunzione, ed energia termica a bassa temperatura, tramite un sistema di recupero termico. La seconda attività concerne lo sviluppo e test sperimentali di un prototipo di sistema di accumulo termico per impianti termodinamici alimentati da sistemi a concentrazione solare. Il sistema di accumulo consente di compensare la natura intermittente e variabile della fonte solare incrementando le ore di funzionamento dell'impianto termodinamico con i conseguenti benefici economici. Concludendo, la presente tesi di dottorato include la descrizione di metodi e strumenti per l'ottimizzazione e valorizzazione delle FER. I risultati evidenziano le criticità e potenzialità dei sistemi studiati con lo scopo di contribuire a una loro diffusione e favorire uno sviluppo sostenibile

La recherche de la performance énergétique dans les bâtiments est devenue un objectif sociétal et réglementaire. De nos jours, un bâtiment doit assurer des conditions de confort, tout en limitant son impact énergétique et environnemental. Les demandes de performances sont telles qu’il n’est plus possible d’appliquer des solutions standards à l’ensemble du bâtiment. Un critère énergétique doit donc être pris en compte au plus tôt dans la conception, ce qui exige dès l’esquisse un travail de plus en plus lourd et complexe. Pour faciliter la prise en compte du critère énergétique, nous avons choisi une approche d’optimisation valorisant la mise en œuvre de la simulation énergétique du bâtiment (quelque soit la méthode de simulation choisie) afin de fournir un outil d’aide à la décision au concepteur à partir du métré et de l’esquisse. La thèse consiste au développement d’une méthodologie commençant par le développement d’un algorithme d’optimisation valorisant la construction séquentielle d’un Kriging sur des paramètres globaux du bâtiment qui permet de rendre le temps de calcul nécessaire compatible avec le contexte de conception d’un bâtiment. Le méta-modèle de Kriging construit peut ensuite être valorisé pour restituer les solutions optimales, permettre l’exploration de l’espace de solutions respectant les contraintes, et mettre en valeur la sensibilité énergétique du bâtiment face aux différents paramètres d’entrée. Le concepteur peut alors faire des choix constructifs optimisés, tout en conservant un certain espace de liberté, ou encore réaliser des modifications à postériori. La dernière étape consiste à inverser la relation liant les paramètres globaux choisis à l’ensemble des données élémentaires de l’ouvrage. L’ensemble de la démarche est appliqué au cas d’une cellule monozone de référence.

Les centrales à concentration utilisent la radiation solaire directe pour produire de la chaleur et, comme dans la plupart des cas, de l’électricité par transformation de cette chaleur. Les centrales dites « à tour » sont associées à un vaste champ héliostatique dont l’alimentation se fait généralement par de longs câbles à l’intérieur de tranchées qui peuvent mesurer plusieurs kilomètres. Pour pallier cette solution, la thèse s’inscrit donc dans l’évaluation de la mise en place d’héliostats autonomes énergétiquement via un générateur solaire et un stockage électrochimique (batteries). Le dimensionnement de ce système est optimisé par la commande des deux moteurs des héliostats (azimut et élévation) en vue de minimiser leur consommation globale. L’impact environnemental global est également comparé par rapport à la solution des tranchées grâce à une analyse de cycle de vie. Cette recherche est effectuée au sein du laboratoire LAPLACE de Toulouse en collaboration avec le laboratoire PROMES d’Odeillo.

This work presents three models that have been developed using individual-based techniques, with the aim of investigating on different aspects of forest ecosystems. The first one studies the relationships between the tree size and the resource use, with focus on the energetic equivalence rule (EER). The EER predicts that in ecological communities at a steady state abundance is counterbalanced by change in metabolic rate, so that energy use is invariant per size class. In forest communities, it is commonly thought that EER holds per unit of ground area. However, no explicit insights have been provided in order to assess the amount of ground area effectively used by any size class, which is crucial for understanding how tree size affects the total productivity of a given site. To address this issue, a simple model has been developed, parametrized on the basis of field data, where patches identical for ground area and resources were filled with different tree size distributions and trees were subject to two constraints: space and belowground resources. The model highlighted that the limiting resource for trees can change depending on size, implying that productivity per unit of ground area varies with it. In addition with experimental data, the model could provide reasons for a forest being stratified or sparse (as at the treeline), thus simply explaining the existence of different forest structures across the globe. Starting from it, a dynamic model has been developed, parametrized on the basis of empirical data, which combines individual-based techniques with a metabolic approach to simulate a forest evolving over time. Being dynamic, the tree distributions are not imposed in the patches, but emerge from the growing and the interactions among trees, resulting hence more similar to the tree distributions observed in real forests. The analysis of the simulation outcomes showed that the model is able for many aspects to reproduce the observed behaviour of real forests, like the self-thinning process, the curve of the aboveground biomass, the mosaic structure and the tree height distribution. A quantitative comparison with two real forest stands showed also a very good fitting with the number of the trees and the percentage of the covered ground area. This makes it especially suitable to highlight the relationship between structure and resource use within forest ecosystems. Moreover, it could be used as an exploration tool, to predict the forest response to different levels of disturbance and/or kinds of management. Finally, the third model has been developed to shed light on the mast seeding phenomenon, in forest ecosystems. Mast seeding is the synchronous production of large amounts of seeds at long intervals in plant populations. It is observed in several genera and its explanation remains controversial. To test one of the most popular hypotheses, predator satiation, I developed a virtual experiment based on an individual-based model reproducing the interaction between trees and seed predators in a simulated forest. This allowed a direct comparison between masting and no-masting cases, as would have been impossible in reality. The large differences observed between the two scenarios strongly supported the hypothesis. At the same time, a second mechanism similar to the classic paradox of enrichment seemed to play a crucial role, working in synergy with predator satiation to keep in check seed predator populations. More generally, I showed that the resource distribution over time can deeply affect population dynamics, even when the overall amount of the resource is kept constant.
Questo lavoro presenta tre modelli che sono stati sviluppati usando tecniche individual-based, con lo scopo di investigare su differenti aspetti di ecosistemi forestali. Il principio di equivalenza energetica (EER) predice che nelle comunità ecologiche in uno stato di equilibrio, l’abbondanza è controbilanciata da cambiamenti del tasso metabolico, cosicché l’uso dell’energia risulta invariante per classi dimensionali. Nelle comunità forestali, generalmente si ritiene che l’EER vale per unità di superficie. Tuttavia, non sono stati fornite indicazioni esplicite per valutare la quantità di superficie effettivamente occupata da una classe dimensionale, cosa cruciale per capire come la dimensione degli alberi influenza la produttività di un dato sito. Per dirimere la questione, è stato sviluppato un semplice modello, parametrizzato sulla base di dati empirici, in cui patch identiche fra loro per superficie e risorse sono state riempite con alberi di diversa dimensione e gli alberi erano soggetti a due vincoli: spazio e risorse ipogee. Il modello ha messo in luce che la risorsa limitante per gli alberi può variare in dipendenza della dimensione, da cui segue che anche la produttività per unità di superficie varia con essa. Combinato con dati sperimentali, il modello può fornire motivazioni sul perché una foresta si presenta stratificata o sparsa (come al limite superiore del bosco), spiegando quindi l’esistenza di diverse strutture forestali. A partire da esso, è stato sviluppato un modello dinamico, parametrizzato sulla base di dati empirici, che combina tecniche individual-based con un approccio metabolico per simulare una foresta che evolve nel tempo. Essendo dinamico, le distribuzioni degli alberi non sono imposte nelle patch, ma sono il risultato della crescita e delle interazioni fra gli alberi, cosa che le rende più simili alle distribuzioni reali osservate in foresta. L’analisi dei risultati delle simulazioni hanno mostrato che il modello per molti aspetti riesce a riprodurre il comportamento osservato delle foreste reali, come il processo dell’autodiradamento, la curva della massa epigea, la struttura a mosaico e la distrubuzione delle altezze degli alberi. Un confronto quantitativo con due plot forestali ha mostrato anche un buon fitting del numero di alberi e della percentuale di superficie coperta. Questo lo rende particolarmente adatto a mettere in luce le relazioni fra struttura e uso delle risorse nell’ambito di ecosistemi forestali. Si presta inoltre ad essere usato come strumento per predire la risposta di una foresta a diversi livelli di disturbo e/o tipi di gestione. Infine, il terzo modello è stato sviluppato per gettare luce sul fenomeno del mast seeding (pasciona) negli ecosistemi forestali. Il mast seeding è la produzione sincronizzata di una grande quantità di semi a lunghi intervalli di tempo in popolazioni di piante. Si osserva in svariati generi e la sua spiegazione rimane controversa. Per testare una delle più popolari ipotesi, la "predator satiation", ho sviluppato un esperimento virtuale basato su un modello individual-based che riproduce le interazioni fra alberi e consumatori di semi in una foresta. Questo ha permesso un confronto diretto—che sarebbe stato impossibile nella realtà—fra una foresta con masting e una senza. L’ampia differenza osservata fra i due scenari supporta fortemente l’ipotesi. Allo stesso tempo, un secondo meccanismo simile al classico "paradox of enrichment" sembra svolgere un ruolo cruciale, agendo in sinergia con il "predator satiation" per tenere sotto controllo la popolazione dei consumatori. Più in generale, ho mostrato che la distribuzione delle risorse nel tempo può fortemente influenzare le dinamiche di popolazione, anche quando la quantità complessiva della risorsa si mantiene costante.

PhD thesis deals with application of simulation and optimization methods in the field of waste and biomass utilization for energy purposes. Current situation in this field is described in the introductory. Following chapters deal with approaches of creating mathematical models of apparatus and processes used in the field of interest for simulation and optimization purposes. Stochastic methods, which are widely applied for real problems solution, are mentioned as well. The core of the thesis consists in proposal of systematic approach and its application for simulation and optimization model building used in the field of interest. The application is demonstrated through two case studies. The first one deals with the building of simulation model of an existing waste-to-energy plant using its operation data. The second study deals with optimization model building and its application for a problem regarding utilization of biomass in an existing energy system.

PhD thesis deals with the application of simulation, forecasting and optimization methods in the waste management. An introduction describes current state and outlook in the waste management in the Czech Republic. The following chapter analyzes the available data base in the field of the waste management in the Czech Republic, focusing on the specifics and problems such as variable availability of spatially and hierarchically structured, heterogeneous input data. The core work is the computational tool named Justine, which represents the balance system, ensuring consistency of values for the standalone and aggregated data, in terms of their composition and distribution in intended area and time. Development of the tool was motivated by the need to predict the production and composition of various types of waste. The application of the concept is shown in three case studies, focusing on the prognosis of hazardous waste, the forecast of production and composition of municipal solid waste and components of separated waste collection, and estimation of the waste with waste-to-energy potential, all in the Czech Republic. The outputs of the tool represent valuable inputs for the related optimization supply chain models, which are used e.g. for the design of new waste-to-energy facilities.

This thesis presents the project for the optimization of the APOLLO3® neutronic calculation scheme applied to the 4th generation fast neutron reactor ASTRID. APOLLO3® is the new multipurpose neutronic platform developed by the CEA. It incorporates many of the previous generation codes used in the French reactor core design supply chain. Like all deterministic codes, APOLLO3® solves the neutron transport equation with a discretization of the variables of interest: multi-group method for the energy, discrete ordinates and spherical harmonics for the angular variable, collision probabilities and characteristics methods for the spatial variable. The resolution of the transport equation handles useful quantities such as the neutron flux and multiplication factor, fission rates and cross sections to understand the physical behaviour of the reactor core. Currently it is not possible to use deterministic codes to simulate an entire reactor with a heterogeneous 3D geometry and a fine energy description, so to simplify the study of complete neutron field at core level, the calculation scheme is divided into two phases: lattice and core calculation. The main purpose of this work is to find an optimal degree of approximations of the calculation scheme for the evaluation of a desired physical effect and of the user constraints. In order to reach this optimum, several studies have been carried out with different levels of approximations. The results have been benchmarked with the ones obtained using the stochastic code TRIPOLI4®, used as a reference and to ensure a good accuracy. Furthermore, several sensitivity studies have been carried out to understand how the different approximations affect the macroscopic cross sections evaluation, because these dependences are not yet fully understood.

Cílem práce byl návrh a implementace řídicích algoritmů pro optimalizaci spotřeby energie elektrického vozidla. Hlavním úkolem byla optimalizace rozložení energie mezi hlavním zdrojem energie (bateriemi) a super-kapacitory v průběhu jízdního cyklu. Jízdní výkonový profil je odhadován a předpovězen na základě 3D geografických souřadnic a matematického modelu vozidla. V první části jsou uvedeny komponenty vozidla a jejich modely. Poté jsou představeny algoritmy na základě klouzavého průměru a dynamického programování. Byly provedeny simulace a analýzy pro demostraci přínosů algoritmů. V poslední části je popsána Java implementace algoritmů a také aplikace pro operační systém Android.

Orientadores: Secundino Soares Filho, Anibal Tavares de Azevedo
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: A otimização determinística da operação de médio prazo de sistemas hidrotérmicos de potência é um problema não-linear de grande porte. Neste trabalho, ele é resolvido com a devida consideração das restrições de fluxo de intercâmbio energético entre os subsistemas em um único modelo. Para tanto, fez-se necessária a representação explícita do balanço energético, definido como a soma das gerações hidro e termelétrica e do intercâmbio líquido, tal que a demanda de carga seja atendida. As dificuldades algébricas e computacionais impostas pela formulação do problema são contornadas por meio de um método de pontos interiores primal-dual não-linear. Nele, é empregada busca unidimensional com filtro que, dada a implementação proposta, apesar de não garantir convergência global, mostrou-se eficaz em todas as instâncias de testes numéricos realizados, dispensando o uso de funções de mérito. A estrutura esparsa bloco-diagonal das restrições do problema é explorada com vistas à obtenção de melhor desempenho computacional. Resultados dos estudos de caso numéricos para dados reais do sistema elétrico brasileiro sob diferentes configurações são apresentados.
Abstract: This work presents the solution of the medium-term operation scheduling problem for hydrothermal power systems, a complex large-scale nonlinear problem, with consideration of power exchange between interconnected systems. This required the need to explicitly represent the power balance nonlinear equations, defined as the sum of hydro and thermal outputs, and net power imports such that load demand is attained. Algebraic and computational difficulties arisen by the problem formulation are overcome by the use of a nonlinear primal-dual interior-point line search filter method. A line search filter procedure is chosen for these are known to generally outperform penalty merit functions. Although the implementation proposed herein does not guarantee global convergence, it has shown to be very efficient for all numerical tests performed. In addition, the problem's block-constraint structure is exploited for means of improved computational efficiency. Results for diverse numerical tests applied to the Brazilian power system are shown.
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica

Con circa il 24% delle emissioni di CO2, il settore dei trasporti rappresenta un punto chiave nell’inquinamento atmosferico. Per questo motivo, negli ultimi anni molte politiche si sono adottate per favorire la produzione di biocombustibili. Il biometano in particolare ha visto crescere il suo share, potendo essere utilizzato sia in forma liquida che compressa. Nel primo capitolo viene presentata una breve introduzione riguardante il problema ambientale legato le emissioni inquinanti. Nel secondo capitolo viene proposta una panoramica dettagliata delle politiche volte alla riduzione delle emissioni. Gli aspetti critici legati ad esse vengono presentati e discussi. Si presenta in particolare la produzione di biometano per le regioni Europa e Cina. A questo riguardo, nel panorama italiano si calcola un valore base minimo di incentivazione compreso tra 0.10 € Sm3 e 0.42 € Sm3. Nel terzo capitolo si espone la tecnologia CNG. Si analizza la possibilità di ottenere CBG dal biometano. Le potenzialità di una stazione alternativa vengono analizzate e confrontate con quelle di una stazione tradizionale buffer. Nel quarto capitolo si espone la tecnologia LNG. La possibilità di ottenere LBG dal biometano viene esposta. Una tecnologia innovativa viene presentata per l’upgrading e la liquefazione. Il consumo specifico associato varia tra 1.284 kWh kg-1 e 1.982 kWh kg-1. Un’ottimizzazione della presente, con recupero della CO2, presenta un consumo specifico di 1.093 kWh kg-1. Una successiva evoluzione per la rimozione dell’H2S viene esposta, presentando un consumo specifico pari a 1.526 kW kg-1. Nell’ultimo capitolo, conclusioni e successivi possibili sviluppi del presente lavoro vengono presentati.
With about 24% of total CO2 emissions, transport sector represents a major item in air pollution. In order to meet the target for the GHG emissions, several policies were introduced, regarding biofuels production and utilization. In this perspective, biomethane production as biofuels is growing quickly since it can be used in the Compressed or Liquefied state. In the first Chapter, a brief introduction regarding the environmental issues associated with the GHG emissions is presented. In the second Chapter, a review over the governmental policies adopted worldwide is presented. Critical aspects and provisions are also discussed. Biogas and biomethane potential as vehicle fuels and achievable production is presented for the European region and the Chinese regions. In Italy, the minimum value of the base incentive was estimated to vary from 0.10 € Sm3 to 0.42 € Sm3. In the third Chapter, the CNG refueling technology is presented and investigated. The possibility of combining biogas plant production and upgrading with CNG refueling stations allows the production of the CBG. In order to evaluate the potential of an alternative refueling station, a comparison was proposed with a traditional buffer station. In the fourth Chapter, the LNG technology is presented. The possibility to achieve LBG is investigated. A novel cryogenic separation technology is proposed to achieve upgrading and LBG production. Specific energy consumption was found to vary between 1.284 kWh kg-1 and 1.982 kWh kg-1. An optimization with the CO2 recovery shows a specific energy consumption of 1.093 kWh kg-1. The possibility to achieve carbon dioxide and hydrogen sulfide was investigated. A final specific energy consumption of 1.526 kW kg-1 was found. In the last Chapter, conclusions of the thesis are reported, with potential future works.

La consommation, en général, représente le processus d’utilisation d’un type de ressource où des économies doivent être réalisées. La consommation d’énergie est devenue l’un des principaux problèmes d’urbanisation et de crise énergétique, car l’épuisement des combustibles fossiles et le réchauffement climatique mettent en péril l’utilisation de l’énergie des plantes. Cette thèse présent une méthode d’économie d’énergie a été adoptée pour la réduction de consommation d’énergie prévu le secteur résidentiel et les maisons passives. Un modèle mathématique basé sur des mesures expérimentales a été développé pour simuler le comportement d’un laboratoire d’essai de l’UPB. Le protocole expérimental a été réalisé à la suite d’actions telles que : la construction de bases de données sur les paramètres, la collecte de données météorologiques, l’apport de flux auxiliaires tout en considérant le comportement humain. L’algorithme de contrôle-commande du système est capable de maintenir une température constante à l’intérieur du bâtiment avec une consommation minimale d’énergie. Les mesures et l’acquisition de données ont été configurées à deux niveaux différents: les données météorologiques et les données sur les bâtiments. La collection de données est faite sur un serveur qui a été mis en œuvre dans l’installation de test en cours d’exécution d’un algorithme complexe qui peut fournir le contrôle de consommation d’énergie. La thèse rapporte plusieurs méthodes numériques pour envisage la consommation d’énergie, utilisée avec l’algorithme de contrôle. Un cas expérimental basé sur des méthodes de calcul dynamiques pour les évaluations de performance énergétique de construction a été faite à Grenade, en Espagne, l’information qui a été plus tard utilisée dans cette thèse. L’estimation des paramètres R-C avec la prévision du flux de chaleur a été faite en utilisant la méthode nodal, basée sur des éléments physiques, des données d’entrée et des informations météorologiques. La prévision d’énergie de consommation présent des résultats améliorés tandis que la collecte de données IoT a été téléchargée sur une carte à base de système de tarte aux framboises. Tous ces résultats ont été stables montrant des progrès impressionnants dans la prévision de la consommation d’énergie et leur application en énergie
Consumption, in general, represents the process of using a type of resource where savings needs to be done. Energy consumption has become one the main issue of urbanization and energy crisis as the fossil depletion and global warming put under threat the planet energy utilization. In this thesis, an automatic control of energy was developed to reduce energy consumption in residential area and passive house buildings. A mathematical model founded on empirical measurements was developed to emphasize the behavior of a testing laboratory from Universitatea Politehnica din București - Université Politechnica de Bucarest - Roumanie. The experimental protocol was carried out following actions such as: building parameters database, collecting weather data, intake of auxiliary flows while considering the controlling factors. The control algorithm is controlling the system which can maintain a comfortable temperature within the building with minimum energy consumption. Measurements and data acquisition have been setup on two different levels: weather and buildings data. The data collection is gathered on a server which was implemented into the testing facility running a complex algorithm which can control energy consumption. The thesis reports several numerical methods for estimating the energy consumption that is further used with the control algorithm. An experimental showcase based on dynamic calculation methods for building energy performance assessments was made in Granada, Spain, information which was later used in this thesis. Estimation of model parameters (resistances and capacities) with prediction of heat flow was made using nodal method, based on physical elements, input data and weather information. Prediction of energy consumption using state-space modeling show improved results while IoT data collection was uploaded on a Raspberry Pi system. All these results were stable showing impressive progress in the prediction of energy consumption and their application in energy field

La valorisation des rejets thermiques industriels par leur conversion en énergie mécanique, et éventuellement en électricité, est un moyen de réduire les émissions de gaz à effet de serre et de réduire la consommation énergétique des industries. La présente bourse de thèse est cofinancée par l’Agence De l’Environnement et de la Maitrise de l’Energie (ADEME) dans ce contexte. Le co-financeur de la thèse, Hevatech, est une entreprise qui exploite le brevet d’un nouveau convertisseur de chaleur en électricité appelé Turbosol®. Turbosol® est un bon candidat pour la valorisation de la chaleur fatale industrielle. Le concept en est au stade du développement du prototype et de l’installation de pilotes sur site. L’originalité du cycle de Turbosol® est la détente quasi-isotherme de la vapeur d’eau. Ainsi, le cycle de Turbosol® est proche du cycle de Carnot. La première partie de la thèse porte sur le cycle de Carnot et la faisabilité d’une machine fonctionnant selon le cycle de Carnot. Une machine fonctionnant selon le cycle de Carnot avec de l’eau changeant de phase pendant le chauffage est modélisée, puis optimisée par maximisation de la puissance nette produite. Les variables de l’optimisation sont les températures de vaporisation et de condensation du fluide cyclé, ainsi que la répartition de la surface d’échange entre l’évaporateur et le condenseur. Puis, dans la seconde partie, le modèle de la machine de Carnot est adapté au cas particulier de Turbosol®. Cela permet de simuler le fonctionnement du prototype de Turbosol. L’étude de sensibilité aux variables de commande du modèle a permis d’identifier la température de vaporisation et le débit massique du fluide de travail comme des variables d’optimisation. Ainsi, le convertisseur est optimisé par maximisation de la puissance nette produite et par maximisation du rendement pour un rejet thermique à valoriser donné
To convert the industrial waste heat into mechanical, or electrical energy, is a way to decrease the greenhouse gases emission and the energy consumption. The present PhD thesis is co-financed by the french Environment and Energy Management Agency (ADEME), in this context. The other co-financer, the company Hevatech, exploits the patent of a new heat converter into electricity named Turbosol®. Turbosol® is a good candidate for the industrial waste heat recovery. The concept is currently developed by the study of a prototype and the installation of the prototype on industrial site. The Turbosol® cycle originality is the quasi-isothermal expansion of the water vapor. Consequently, the Turbosol® cycle is close to the Carnot cycle. In the manuscript first part, the possibility of the feasibility of an engine operating according to the Carnot cycle is studied. A Carnot engine with a changing phase working fluid is modeled and optimized by maximization of the net power output. The variables are the optimal vaporization and condensation temperatures, and the optimal allocation of a total thermal transfer area between the condenser and the evaporator. Then, in the second part, the model of the Carnot engine is adapted to the Turbosol® prototype. In the sensitivity analysis, the vaporization temperature and the mass flow rate of the working fluid are identified as optimization variables. So, the Turbosol® converter is optimized by maximization of the net power output and the first law efficiency for a given waste heat fluid to valorize

La crise énergétique marquée par une flambée des prix du pétrole et les impératifs d’un développement durable font des énergies renouvelables une alternative qui suscitent aujourd'hui l’intérêt de plusieurs équipes de recherches. Le Sénégal, pays subsaharien, non producteur de pétrole n’est pas épargné par cette crise. Celle-ci se traduit par, une faible couverture du pays (en particulier les zones rurales) par le réseau électrique national. Pour faire face à cela, la nouvelle orientation en matière de politique énergétique met l’accent sur l’utilisation des énergies renouvelables notamment, le solaire et l’éolienne. L'objectif principal de cette thèse est de dégager une méthodologie de conception d’un site isolé de production d’énergie électrique à partir des énergies alternatives. Il s'agit à partir des caractéristiques d’un site (ressources d’énergie disponibles, besoins énergétiques) de :- mettre en place une démarche qui permette le choix d’une architecture du réseau et de dimensionner de façon optimale l’ensemble des constituants du réseau (machines, sources et dispositifs de stockage) en tenant compte de toutes les contraintes- concevoir un dispositif de commande des composantes et de gestion des flux d’énergie Cette thèse comprend trois chapitres :- Chapitre 1 : pose la problématique de l’énergie au Sénégal. L’organisation institutionnelle du sous-secteur de l’électricité, les réalisations et les projets en cours sont présentés. Aussi, une étude sur les architectures de micro-réseaux est faite. - Chapitre 2 : traite des outils et logiciels. Une étude comparative des principaux logiciels d’analyse, de conception et simulation des micro-réseaux est réalisée. L’ensemble des composants de notre système ont été modélisées. Les méthodes d’optimisation et des outils de représentation graphique (Bond Graph, GIC et REM) des systèmes ont été présentés. Une enquête menée et une recherche bibliographique nous ont permis d’évaluer le potentiel énergétique du site et les besoins des populations.- Chapitre 3 : il s’agit de l’application de notre outil sur un site isolé identifié au Sénégal (MBoro/Mer). L’optimisation à travers la fonction objectif coût annualisée du système (ACS) nous a permis de dimensionner de façon optimale notre système. Aussi la commande du système avec la Représentation Energétique Macroscopique (REM) a été conçue.Pour la suite du travail, il faudrait envisager une prise en charge des problèmes de disponibilité du système à travers une surveillance et une supervision du dispositif. Le volet socio-économique aussi est à intégrer dans le futur afin de satisfaire l’évolution des besoins et des habitudes des populations
The energy crisis characterized by the oil products price rising and the imperatives of sustainable development do that renewable energies are an alternative today witch attract the interest of several research teams. Senegal, sub-Saharan country, not oil producer is not spared by this crisis. The consequence of this is a low coverage of the country (especially rural areas) by the national grid. For solving this, the new orientation of the energy policy focuses on the use of renewable energy particularly solar and wind.The main objective of this thesis is to identify a methodology of design of an isolated site of electrical energy production from alternative energies It is consists on, from site characteristics (energy resources, energy requirements):- to develop an approach that allows the choice of network architecture and sizing optimally all components of the network (machines, sources and storage devices) taking into account all the constraints- to design a device for controlling components and managing the energy flowsThis thesis contains three chapters:- Chapter 1 - poses the problem of energy in Senegal. The institutional organization of the electricity sub-sector and the ongoing projects are presented. Also, a study of micro- architectures networks is made.- Chapter 2 deals with tools and software. A comparative study of the main software of analysis, design and simulation of micro- network is realized. The components of our system have been modeled. Optimization methods and tools for graphical representation (Bond Graph, GIC and EMR) systems were presented. A survey and a literature review allowed us to evaluate the energy potential of the site and the needs of populations.- Chapter 3: This is the application of our tool on an isolated site identified in Senegal (MBoro / Mer). Optimization through the Annualized Cost of the System (ACS) objective function has allowed us to scale our system optimally. As the control system with Energetic Macroscopic Representation (EMR) has been designed.For further work should be considered a treatment of problems of availability of the system through monitoring and supervision of the system. The socio- economic component is also integrated in the future to meet the changing needs and habits of the population

The diploma thesis deals with the behavior of technical systems of the student dormitory in Brno. The temperature and humidity climate was measured and evaluated in the building. The measurement is then compared with the computer simulation created in DesignBuilder. The geometric model of the building was created in Revit, which supports BIM technology. Based on the evaluation of the experiment, the optimization of the technical systems in the building was proposed.

Une grande partie de la consommation d'énergie dans les bâtiments est due aux systèmes de chauffage, de ventilation et de climatisation. Entre autres systèmes, les systèmes de réfrigération font l'objet de mesures d'amélioration de l'efficacité. Néanmoins, les conditions opérationnelles réelles de ces installations et leurs performances doivent être connues, ainsi que tout potentiel d'optimisation éventuel, avant que des améliorations puissent être réalisées. Les analyses exergétique et énergétiques ont été largement utilisées pour évaluer la performance des systèmes de réfrigération. Entre autres, l'efficacité exergétique est utilisée comme indicateur pour déterminer la performance du système, mais les valeurs réalisables dans la pratique sont inconnues. Par conséquence, ce travail propose une méthode d'évaluation pratique des systèmes de réfrigération basée sur une analyse exergétique et des normes techniques comme base de référence. L'identification des améliorations possibles est pertinente dans la pratique, car les mesures qui améliorent l'efficacité du système permettent probablement d'éviter de fréquentes déficiences pendant l'usage. Avec l'optimization potential index (OPI) introduit dans cet ouvrage, les améliorations réalisables par rapport à l'état de l'art de la technologie et la performance sont identifiées d'un seul coup d’œil, quelle que soit la complexité du système. En divisant l'installation en sous-systèmes, chacun peut être évalué individuellement. Les non-spécialistes peuvent facilement déterminer l'état de fonctionnement du système et ensuite, si nécessaire, lancer une analyse détaillée ainsi que des contre-mesures appropriées. De plus, la modélisation est considérée comme une méthode appropriée pour déterminer des valeurs de référence. Parmi les différentes techniques, les modèles artificial neural network révèlent les meilleures performances pour l'application présentée. L'application, la fonctionnalité et l'objectif de la méthode présentée sont illustrés par deux cas numériques et sur une installation réelle. La recherche révèle un fonctionnement approprié de l'installation étudiée en général, où trois des sept espaces conditionnés ont des problèmes de performance. La raison devrait être identifiée dans une étude détaillée ultérieure. Dans l'ensemble, l'apport d'exergie électrique auxiliaire est du même ordre que l'apport d'exergie thermique. Cela souligne l'importance de réduire la consommation d'énergie électrique au minimum, car elle constitue le facteur principal dans le coût d'exploitation des installations de réfrigération et permet également d'augmenter la performance du système. En outre, les concepts de mesure des systèmes réels sont analysés et les coûts de mise à jour correspondants pour l'application de l'approche présentée sont identifiés. Il est démontré qu'une mise à jour de l'instrumentation peut être rentable, si l'installation frigorifique comprend déjà un concept de mesure proche de l'état de la art
A significant amount of energy consumption in buildings is due to heating, ventilation and air-conditioning systems. Among other systems, refrigeration plants are subject of efficiency improvements. However, actual operating conditions of such plants and the performance must be known as well as any eventual optimization potential identified before enhancements can take place. Energy and exergy analyses have been widely used to assess the performance of refrigeration systems. Among others, exergy efficiency is used as an indicator to determine the system performance; however, the practical achievable values are unknown. Therefore, this work proposes a practice-oriented evaluation method for refrigeration plants, based on exergy analysis and technical standards as baseline. The identification of possible enhancements is highly relevant in practice, as measures which improve the system effectiveness most likely prevent frequent shortcomings during refrigeration plant operation. With the introduced optimization potential index (OPI), the achievable enhancements compared to the state of the art in technology and the performance are identified at a glance regardless the complexity of the system. By dividing the plant into different subsystems, each of them can be assessed individually. Laypersons can easily determine the system operating state and subsequently, if needed, initiate a detailed analysis as well as appropriate countermeasures by specialist. Moreover, modeling is seen as an appropriate method to determine additional reference values for refrigeration machines if none are available according to technical standards. Among different modeling techniques, artificial neural network models reveal the best performance for the present application. The application, functionality and purpose of the presented method is exemplified on two numerical test cases and on a real field plant as a case study. The investigation reveals an adequate operation of the studied field plant in general, where three out of seven cooling locations have performance issues. The reason should be identified in a subsequent detailed study. Overall, the auxiliary electrical exergy input shows the same magnitude as the thermal exergy input. This emphasizes the importance of minimizing the electrical energy usage, as it is the main overhead in the operating cost of refrigeration plants and also to achieve an increase in system performance. Moreover, measuring concepts of real systems are analyzed and the corresponding retrofitting costs for the application of the presented approach are identified. It is shown that a retrofit of the instrumentation can be worthwhile if the refrigeration plant already comprises a measuring concept close to the state of the art

The dissertation thesis is focused on the issue of energy recovery of waste. It contributes to optimization models developed in the author's workplace in the long term, which serve to simulate material flows in waste management and to search for an optimal waste management strategy. The main objective is to assess the potential for the use of heat produced in waste-to-energy plants as a key factor for the economy of these facilities. The thesis therefore represents an activity on the border of the fields of waste management and heating. Partial mathematical models were developed within the scope, for which it was necessary to collect input data, especially in relation with district heating networks. These models were then used in a comprehensive optimization model describing the integration of waste-to-energy plants with other heat sources. This main model was extended to include the environmental aspect.

This thesis is focused on identifying main factors influencing economical rentability of energy generated using incineration of municipal waste. Research was conducted focusing on municipal waste management, waste-to-energy possibilities and the issue of district heating systems, which are important considering the economy of waste-to-energy plants. Main limiting factors were identified using mathematic models adjusted for specific geographic locations.

Cette thèse porte sur l’étude du comportement thermique des systèmes photovoltaïques (PV). La première partie de la thèse rassemble et étend l’état de l’art sur la dépendance en température des rendements de conversion PV. L’analyse détaille l’ensemble des phénomènes physiques mis en jeu afin d’améliorer la compréhension des coefficients de température des différentes technologies de cellules PV. La seconde partie de la thèse recense les travaux de recherches effectués pour mitiger l’impact négatif de la température sur les performances des systèmes PV et propose une approche originale qui consiste à prendre en compte les conditions de fonctionnement du système dans le processus d’optimisation de ses caractéristiques. Afin de réaliser de telles optimisations, un modèle thermique complet et général pour les systèmes de conversion photovoltaïque est développé. Enfin, des applications à des systèmes photovoltaïque et thermophotovoltaïque démontrent la pertinence de l'approche proposée
This Ph.D. thesis manuscript reports on a study about the physics of the thermal behavior of photovoltaic (PV) systems. While it is long known that the conversion efficiency of PV devices deteriorates when their temperature increases, a detailed analysis of all the mechanisms involved was not available to date in the literature. Part I of this manuscript gathers and extends the existing works on the topic in order to offer a comprehensive view of the physics involved in the temperature sensitivities of PV systems. First, temperature coefficients, which quantify the temperature dependences, are analyzed in the radiative limit (which is the fundamental limit for PV conversion). Then, the additional loss mechanisms of real PV devices are introduced and their impacts on the temperature coefficients are assessed. The existing theoretical expressions of the temperature coefficients of important solar cell parameters (namely open-circuit voltage, short-circuit current and fill factor) are reviewed. A new formulation of the temperature coefficient of the open-circuit voltage that incorporates the concept of External Radiative Efficiency (ERE) is proposed. The theoretical expressions are compared to experimental results on crystalline silicon cells from measurements made at the University of New South Wales (UNSW, Australia) and from the literature. Using the understanding of the relation between the temperature coefficients and device physics, the special cases of silicon heterojunction cells and cells made from compensated silicon are examined. Because temperature has a critical impact on the performances of PV devices, several studies aimed on the one hand at predicting the temperature of PV modules from their operating conditions and on the other hand at designing inexpensive cooling solutions. The goal of Part II of this manuscript is to propose an original approach to minimize the temperature-induced losses in PV systems. The idea is to include the operating conditions in the optimization of the system parameters in order to maximize the power produced in these conditions rather than in the Standard Test Conditions (STC). These original optimizations are based on a comprehensive thermal model of PV cells that captures all of the physical mechanisms involved in the generation of heat within the cell. Following the presentation of this thermal model, several examples of global optimization (i.e. a thermal criterion is added to the usual optical and electrical ones) are presented. Some of these examples apply to standard solar cells while others demonstrate that this kind of optimization can be applied to other PV systems such as thermophotovoltaic (TPV) converters (solar or near-field TPV). The recent trend of the PV industry towards the creation of products specifically adapted to a given use suggests that these original optimizations that take into account the system operating conditions could be implemented in the near future

Orientador: Alberto Luiz Francato
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-09T18:59:36Z (GMT). No. of bitstreams: 1 Franco_HermasTeixeira_M.pdf: 12981499 bytes, checksum: 1cc917f0c21b08e2633be79cc8d29042 (MD5) Previous issue date: 2006
Resumo: Este trabalho tem como objetivo construir uma ferramenta de suporte à decisão que permita avaliar de maneira fácil e rápida as alternativas existentes para a otimização energética do aproveitamento conjunto da operação multipla de um "Sistema Reservatório" já existente com vistas à maximização dos benefícios deste sistema. Definiu-se (para uso neste trabalho) a expressão "Sistema Reservatório"? como sendo um conjunto de reservatórios hídricos que propõe-se administrar. Definiu-se ainda (no âmbito deste trabalho) como benefícios a energia potencial gravitacional total (dentro do horizonte de planejamento) dos recursos hídricos compreendidos neste estudo. Para avaliar estas alternativas de otimização foi desenvolvido um especial sistema de suporte à decisão para ser usado pelos operadores do sistema podendo subsidiar o processo da tomada das decisões. Procurou-se construir esta ferramenta de tal forma que fosse constituida por um sistema computacional em ambiente gráfico (Windows ®) com interface amigável ao usuário (F-GUI - Friendly Grafic User Interface), para ser usada de forma contínua e que fosse também de fácil implantação. O arcabouço teórico utilizado pelo sistema foi o da concepção de Sistema de Suporte à Decisão para a modelagem do sistema em estudo, tendo usado a técnica de Programação Não Linear para a etapa da otimização. As funções da otimização multi-objetivo inerentes à produção de energia elétrica ou reservação de volumes d'água para a mesma finalidade, são tratadas pelo método das ponderações, ficando a cargo dos operadores do sistema a calibração dos fatores sob diferentes situações de carga. Este trabalho utilizou os dados disponibilizados pela AES Tietê referentes a cinco reservatórios-usinas sequenciais no Rio Tietê, três reservatórios-usinas sequencias no Rio Pardo, um reservatório-usina no Rio Grande e um reservatório-usina no Rio Mogi-Guaçu, todos situados na região Sudeste do Brasil
Abstract: This dissertation has the objective of build a Decision Support Tool that gives a quick and easy way to analyze all the different alternatives to manage integrated a complex of hydroelectric reservoirs seeking the maximization of the benefits of the complex. The benefits of the complex were defined as the total potential gravitational energy of the hydraulic resources included in the system in the period of the planning horizon. This tool had being built looking for a computer Friendly Graphic User Interface based in the Microsoftã Windows Operational System to make easy the use of the tool day by day and also the initial installation in the users computers. The theory used were the conception of the Decision Support Tool in the modeling phase study and the Non Linear Programming in the optimization phase. This dissertation has used the data provided by the owner of the power generation complex -AES Tiete- that include five reservoirs in the Tiete river basin, three reservoirs in the Pardo river basin, one reservoir in the Grande river basin and one reservoir in the Mogi-Guaçu river basin, all of them in the southeast region of Brasil, South America
Mestrado
Recursos Hidricos
Mestre em Engenharia Civil

This master's thesis analyzes optimization of operation of the heating system after its reconstruction. For application of this theme was chosen school building in the complex of SOU and SOŠ Bosonohy. This work first analyze the object where is described the character of the building and as next examination of the building cloak by using infrared thermography and finally evaluation of the energy performance of the building before and after reconstruction using an proof of energy building performance. The aim of this work is optimization of the heating system. This topic is dealing with optimal settings heating curve for equithermic regulation and next the optimization of heating operation.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O bagaço e a palha são resíduos do processamento industrial da cana-de-açúcar que constituem uma importante fonte de recurso para cogeração de energia no setor sucroalcooleiro. Os sistemas de cogeração neste setor geram potência mecânica ou elétrica e vapor, que são utilizados no próprio processo e o excedente é vendido as concessionárias de energia. Porém, estes sistemas encontram-se bem abaixo do potencial real. Uma alternativa tecnológica que poderá contribuir com a oferta de excedentes de energia elétrica é a introdução da tecnologia BIG-GT (gaseificadores de biomassa associados a turbina a gás e caldeira de recuperação). O presente trabalho, tem como objetivo o estudo termoeconômico da incorporação desta tecnologia em usinas sucroalcooleiras como alternativa para o aumento de geração de eletricidade. As análises energéticas e exergéticas foram realizadas para quatro possíveis configurações de uma usina sucroalcooleira com a integração da tecnologia BIG-GT com o objetivo de avaliar a eficiência de geração de eletricidade e vapor de processo, bem como o aproveitamento global de energia de cada uma delas. Na análise termoeconômica, é determinado o custo de produção de gás de gaseificação, eletricidade e vapor do processo no sistema proposto, assim como, tempo de recuperação do investimento. Na parte final do trabalho foi realizada a otimização multiobjetiva do sistema considerando três funções objetivo: tecnológica, econômica e ambiental, para identificar a configuração com melhor comportamento. De acordo com os resultados obtidos no estudo conclui-se que o caso III que estuda a gaseificação em leito fluidizado circulante pressurizado e mistura de oxigênio-vapor de gaseificação e o caso IV que além da gaseificação em leito fluidizado circulante pressurizado com mistura de oxigênio-vapor estuda a queima suplementar de palha na caldeira de recuperação, apresentam-se como as melhores das opções propostas.
Bagasse and straw are residues from the industrial processing of sugarcane that constitute an important source for cogeneration of energy in the sugar-alcohol sector. The cogeneration systems in this sector generate mechanical or electrical power and steam, which are used in the process itself and the surplus is sold to energy distribution companies. However, these systems are well below real potential. One of the technological alternatives that may improve the supply of surplus electricity is the introduction of BIG-GT technology (biomass gasifier associated with gas turbine and Heat recovery steam generator). In this work, it is proposed to conduct thermoeconomic studies of the incorporation of this technology in the sugarcane ethanol plants as an alternative to increasing the supply of electricity generation. The energetic and exergetic analyses were performed for four possible configurations of a sugarcane ethanol plant with the integration of BIG-GT technology with the objective of evaluating the efficiency of electricity generation and process steam as well as the global energy utilization of each one of them. In the thermoeconomic analysis, it is determined the cost of production of producer gas, electricity and steam of the process in the proposed system, as well as the investment payback period. In the final part of the work, it is developed the multiobjective optimization of the system considering three objective functions: technological, thermoeconomic and environmental, for identifying the configuration with better behavior. According to the results obtained in the study, it is concluded that case III and case IV are presented as the best of the proposed options.
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Buildings are at the centre of our social and economic activity. Not only do we spend most of our lives in buildings, we also spend most of our money on buildings. The built environment is not only the largest industrial sector in economic terms, it is also the largest in terms of resource flow1. The rising energy costs, the growing concern about environmental issues and the approaching exhaustion of world energy resources are urging the entire European Community and the several national governments to improve energy management. Special attention is usually paid to public administrations, as European and national legislations often point out that these bodies must provide energy efficiency measures, as well as for the reasons mentioned above, also in order to represent an example for the entire community and for citizens as well. But it is also very important to find out how to foster and encourage energy efficiency improvements and saving measures in private dwellings to achieve the double advantage of reducing the global energy consumption level within the private sector and increasing investments, favoring the creation of additional cash flows as well. The possible combination of such multiple benefits makes the building sector a crucial field for policy makers at EU and national levels. Hence a policy framework that supports national markets in unlocking these potentials is strongly needed. With overall European policy aimed at significantly decarbonizing its economy by 80% to 95% by 2050, the building sector must undoubtedly play a key role. And any strategy to tackle the challenge in this field will clearly require both a significant amount of financial investments and long-term political commitments. The main goal of the present research is to propose an optimized methodology and cost effective decision-making process - based on the main facts emerging from the adoption of the key energy policies and financial instruments currently in force at European level (particularly in Italy and Denmark) - also to outline the next policy steps in improving the energy performance of buildings. After a global overview of the policies adopted at European level, the analysis focuses on the two different regulations implemented at the national level by Italy and Denmark. Furthermore, to define the best mixture of energy retrofit measures for the different geographical areas of Italy - applying a methodology based on simple and available data to improve residential buildings' energy efficiency - the work started with the analysis of the several reports produced by ENEA (the Italian Research Agency for Energy Efficiency) since year 2007. These were based on the data collection performed in order to assess the effectiveness of the Italian government’s financial policies established to support energy saving actions in private dwellings. The first steps of such a top-down analysis are then carried out both through manual cost/benefit spreadsheets, as well as with the implementation of a linear programming analysis tool. The study defines different linear programming models, depicting different optimization problems (e.g. energy saving maximization vs. retrofit cost minimization), along with the respective different background scenarios. Such investigations are therefore carried out through the implementation and development of Dantzig's simplex algorithm. Moreover, to carry out a global comparison between the overall Italian and Danish situations, also achieving a deeper single-dwelling-focused analysis, further studies are developed through a Building Energy Optimization tool, implementing the EnergyPlus dynamic energy simulation software. Thence, the research moves on to a more specific analysis, shifting to a bottom-up approach and involving in the enquiry a comparison between the different assessment settings (climatic, political, economic, cultural) depicted both by Italy and Denmark. Two different dwelling models are defined for the above countries, focusing the analysis on those building typologies most representative of such European nations and thence different retrofit solutions are depicted and analyzed. The results obtained by means of this dynamic assessment are then used to group the respective energy savings vs. retrofit cost considerations within a global cost-effectiveness assessment. Finally, some “guidelines” are outlined to address the challenge of renovating the existing building stock, also in order to keep pace with the aims of both the nations and the European Union.