Este trabalho é um estudo da aplicação de um sistema que utiliza a cogeração para hotéis localizados na cidade de Porto Alegre, RS, Brasil. Foi analisada a implantação desse tipo de sistema, também chamado de CHP (Combined Heat and Power), de um ponto de vista econômico e energético. A questão econômica foi determinada pela viabilidade através de métodos de análise quantitativa, neste caso, dando enfoque ao tempo de retorno do investimento. Para a análise energética foi realizado o estudo dos consumos e demandas anuais da operação do prédio através da ferramenta de simulação térmo-energética de edificações. O software escolhido foi o EnergyPlus. Essas análises, energéticas e econômicas, foram realizadas através de uma comparação entre o hotel sem o sistema de CHP e o hotel com o sistema de CHP. O hotel hipotético simulado foi definido através de um levantamento de informações a respeito do desempenho energético de hotéis que funcionam em Porto Alegre. Além dos estudos energéticos e econômicos, foram realizadas variações em parâmetros do hotel para tentar abranger uma série de possíveis cenários e verificar suas viabilidades econômicas. Foi visto que a cogeração pode trazer redução de custo operacional mesmo não tendo um menor consumo energético anual. Em alguns cenários o tempo de retorno do investimento apresentou valor abaixo dos seis anos, sendo considerado como uma boa opção de investimento. / This work is a study of the application of a CHP (Combined Heat and Power) system in hotels built in the city of Porto Alegre, RS, Brazil. This system was analyzed from an economic and energetic point of view. The economic matter on its viability perspective was determined through quantitative methods, in this case, with the focus on the time frame for the investment's return. For the energetic analysis, a annual energy consumption and demand study was performed utilizing a whole-building energy model with computer simulation. The chosen software was EnergyPlus. The analyses, energetic and economic, were performed through a comparison between the hotel without the CHP system and with the CHP system. The hypothetic simulated hotel was determined by a data survey on the energetic performance of hotels build in Porto Alegre. In addition to the energetic and economic studies, some parametric variations to the hotel were made to include a series of possible scenarios and check their economic viability. It was observed that the CHP can provide some operational cost reductions even without presenting a lower annual energetic consumption. In some scenarios, the time to return the investment showed figures lower than six years, being considered a good investment option.

Este trabalho é um estudo da aplicação de um sistema que utiliza a cogeração para hotéis localizados na cidade de Porto Alegre, RS, Brasil. Foi analisada a implantação desse tipo de sistema, também chamado de CHP (Combined Heat and Power), de um ponto de vista econômico e energético. A questão econômica foi determinada pela viabilidade através de métodos de análise quantitativa, neste caso, dando enfoque ao tempo de retorno do investimento. Para a análise energética foi realizado o estudo dos consumos e demandas anuais da operação do prédio através da ferramenta de simulação térmo-energética de edificações. O software escolhido foi o EnergyPlus. Essas análises, energéticas e econômicas, foram realizadas através de uma comparação entre o hotel sem o sistema de CHP e o hotel com o sistema de CHP. O hotel hipotético simulado foi definido através de um levantamento de informações a respeito do desempenho energético de hotéis que funcionam em Porto Alegre. Além dos estudos energéticos e econômicos, foram realizadas variações em parâmetros do hotel para tentar abranger uma série de possíveis cenários e verificar suas viabilidades econômicas. Foi visto que a cogeração pode trazer redução de custo operacional mesmo não tendo um menor consumo energético anual. Em alguns cenários o tempo de retorno do investimento apresentou valor abaixo dos seis anos, sendo considerado como uma boa opção de investimento. / This work is a study of the application of a CHP (Combined Heat and Power) system in hotels built in the city of Porto Alegre, RS, Brazil. This system was analyzed from an economic and energetic point of view. The economic matter on its viability perspective was determined through quantitative methods, in this case, with the focus on the time frame for the investment's return. For the energetic analysis, a annual energy consumption and demand study was performed utilizing a whole-building energy model with computer simulation. The chosen software was EnergyPlus. The analyses, energetic and economic, were performed through a comparison between the hotel without the CHP system and with the CHP system. The hypothetic simulated hotel was determined by a data survey on the energetic performance of hotels build in Porto Alegre. In addition to the energetic and economic studies, some parametric variations to the hotel were made to include a series of possible scenarios and check their economic viability. It was observed that the CHP can provide some operational cost reductions even without presenting a lower annual energetic consumption. In some scenarios, the time to return the investment showed figures lower than six years, being considered a good investment option.

Este trabalho é um estudo da aplicação de um sistema que utiliza a cogeração para hotéis localizados na cidade de Porto Alegre, RS, Brasil. Foi analisada a implantação desse tipo de sistema, também chamado de CHP (Combined Heat and Power), de um ponto de vista econômico e energético. A questão econômica foi determinada pela viabilidade através de métodos de análise quantitativa, neste caso, dando enfoque ao tempo de retorno do investimento. Para a análise energética foi realizado o estudo dos consumos e demandas anuais da operação do prédio através da ferramenta de simulação térmo-energética de edificações. O software escolhido foi o EnergyPlus. Essas análises, energéticas e econômicas, foram realizadas através de uma comparação entre o hotel sem o sistema de CHP e o hotel com o sistema de CHP. O hotel hipotético simulado foi definido através de um levantamento de informações a respeito do desempenho energético de hotéis que funcionam em Porto Alegre. Além dos estudos energéticos e econômicos, foram realizadas variações em parâmetros do hotel para tentar abranger uma série de possíveis cenários e verificar suas viabilidades econômicas. Foi visto que a cogeração pode trazer redução de custo operacional mesmo não tendo um menor consumo energético anual. Em alguns cenários o tempo de retorno do investimento apresentou valor abaixo dos seis anos, sendo considerado como uma boa opção de investimento. / This work is a study of the application of a CHP (Combined Heat and Power) system in hotels built in the city of Porto Alegre, RS, Brazil. This system was analyzed from an economic and energetic point of view. The economic matter on its viability perspective was determined through quantitative methods, in this case, with the focus on the time frame for the investment's return. For the energetic analysis, a annual energy consumption and demand study was performed utilizing a whole-building energy model with computer simulation. The chosen software was EnergyPlus. The analyses, energetic and economic, were performed through a comparison between the hotel without the CHP system and with the CHP system. The hypothetic simulated hotel was determined by a data survey on the energetic performance of hotels build in Porto Alegre. In addition to the energetic and economic studies, some parametric variations to the hotel were made to include a series of possible scenarios and check their economic viability. It was observed that the CHP can provide some operational cost reductions even without presenting a lower annual energetic consumption. In some scenarios, the time to return the investment showed figures lower than six years, being considered a good investment option.

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The global interest in green vehicleshas been growing since it is letting out less pollution than normal internal combustion engines (ICE) and many people want to get into the ecological-friendly alternative mode of transport. The solar car is one of these types of green vehicles, which is powered by renewable energy with zero emissions. The solar car makes use of its solar panel that uses photovoltaic cells to convert sunlight into electricity to the batteries and to also power the electric motor. The state of solar cars is that it is almost exclusively for competition and when competing a strategy is needed to get the best placement. Having knowledge about how the car is behaving is a good basis for building a driving strategy. Therefore, a case study is made on World Solar Challenge (WSC) focused on the cars of JU Solar team with the use of datasets such as topographical data and solar irradiation. An optimization model is made that inputs these datasets and simulates a time period (an hour) and checks the set battery discharge rate (BDR or C rating). It is concluded that a safe BDR is between 8 to 9 % per hour (i.e. 0.08 to 0.09 C), relative to the full capacity of the battery. Results shows an improved mean speeds of the solar cars and improved finish times. The model also works very well for solar cars that are not meant for racing. Since it keeps a relatively stable state of charge for long term driving, that ensures battery longevity. With these results JU Solar team can use this model to improve their driving strategy but could also be used for economical driving for the future of commercial solar cars. This paper recommends to follow a simple procedure, to keep the BDR on 9% as long as the sun irradiation stays above 800 W/m2, and lower the BDR to 8% if irradiation goes below 800 W/m. Adjustments to increase the BDR for the end of the race is also recommended for optimal driving strategy.

No description available.

Ce travail a pour objet de développer une nouvelle technologie de l’énergie solaire à concentration. Il porte sur la présentation du concept, la réalisation prototypique et l’étude optique et énergétique d’un nouveau concentrateur solaire QingSun™. Ce concentrateur a une forme de parallélépipède rectangulaire et comporte des lentilles de Fresnel linéaires, des parois tapissées de miroir et d’un récepteur solaire mobile entraîné par un système de suivi à l’intérieur du caisson de concentration. Un modèle optique et un modèle énergétique ont été élaborés et validés avec une série d’expériences. Ils ont permis d’étudier le fonctionnement et les performances énergétiques du concentrateur. Une étude de l’influence paramétrique de l’inclinaison et l’orientation a été effectuée et a montré que l’inclinaison a plus d’influence que l’orientation sur les performances. Enfin, les performances énergétiques optimales du concentrateur ont été estimées. / This work is for the purpose to develop a new solar concentrating technology. It covers the presentation of the concept, the prototype realization and the optical and energy study of a new solar concentrator QingSun™. This concentrator has a shape of rectangular parallelepiped and includes linear Fresnel lenses, mirror-lined walls and a mobile solar receptor controlled by a tracking system inside the casing. An optical model and an energy model were developed and validated with a series of experiments. The both models permitted us to examine the function and the energy performance of the concentrator. A parametric study of the influence of the tilt and the orientation was performed and showed that the tilt had more influence than the orientation. Finally, the optimal energy performance of this concentrator was estimated.

Cette thèse aborde des aspects fondamentales et appliquées de la théorie des verres de spin etplus généralement des systèmes complexes. Les premiers modèles théoriques décrivant la transitionvitreuse sont apparues dans les années 1970. Ceux-ci décrivaient les verres à l'aide d'interactionsaléatoires. Il a fallu alors plusieurs années avant qu'une théorie de champs moyen pour ces systèmessoient comprises. De nos jours il existe un grand nombre de modèles tombant dans la classe de« champs moyen » et qui sont bien compris à la fois analytiquement, mais également numériquementgrâce à des outils tels que le monte-carlo ou la méthode de la cavité. Par ailleurs il est bien connu quele groupe de renormalisation a échoué jusque ici à pouvoir prédire le comportement des observablescritiques dans les verres hors champs moyen. Nous avons donc choisi d'étudier des systèmes eninteraction à longue portée dont on ignore encore si la physique est identique à celle du champmoyen. Nous avons montré dans une première partie, la facilité avec laquelle on peut décrire unetransformation du groupe de renormalisation dans les systèmes ferromagnétiques en interaction àlongue portée dé finies sur le réseau hiérarchique de Dyson. Dans un second temps, nous avons portéenotre attention sur des modèles de verre de spin sur ce même réseau. Un début d'analyse sur cestransformations dans l'espace réel est présenté ainsi qu'une comparaison de la mesure de l'exposantcritique nu par différentes méthodes. Si la transformation décrite semble prometteuse il faut cependantnoter que celle-ci doit encore être améliorée afin d'être considérée comme une méthode valide pournotre système. Nous avons continué dans cette même direction en analysant un modèle d'énergiesaléatoires toujours en utilisant la topologie du réseau hiérarchique. Nous avons étudié numériquementce système dans lequel nous avons pu observer l'existence d'une transition de phase de type « criseentropique » tout à fait similaire à celle du REM de Derrida. Toutefois, notre modèle présente desdifférences importantes avec ce dernier telles que le comportement non-analytique de l'entropie à latransition, ainsi que l'émergence de « criticalité » dont la présence serait à confirmer par d'autres études.Nous montrons également à l'aide de notre méthode numérique comment la température critique dece système peut-être estimée de trois façon différentes.Dans une dernière partie nous avons abordé des problèmes liés aux systèmes complexes. Il aété remarqué récemment que les modèles étudiés dans divers domaines, par exemple la physique, labiologie ou l'informatique, étaient très proches les uns des autres. Ceci est particulièrement vrai dansl'optimisation combinatoire qui a en partie été étudiée par des méthodes de physique statistique. Cesméthodes issues de la théories des verres de spin et des verres structuraux ont été très utilisées pourétudier les transitions de phase qui ont lieux dans ces systèmes ainsi que pour inventer de nouveauxalgorithmes pour ces modèles. Nous avons étudié le problème de l'inférence de modules dans lesréseaux à l'aide de ces même méthodes. Nous présentons une analyse sur la détection des modules topologiques dans des réseaux aléatoires et démontrons la présence d'une transition de phase entre une région où ces modules sont indétectables et une région où ils sont détectables. Par ailleurs, nous avons implémenté pour ces problèmes un algorithme utilisant Belief Propagation afin d'inférer les modules ainsi que d'apprendre leurs propriétés en ayant pour unique information la structure du réseau. Finalementnous avons appliqué cet algorithme sur des réseaux construits à partir de données réelles et discutonsles développements à apporter à notre méthode. / This thesis presents fundamental and applied aspects of spin glasses theory and complex systems. The first theoretical models of spin glasses appeared during the 1970. They were modelling glassy systems by using random interactions. It took several years before a mean-field theory of spin glasses was solved and understood. Nowadays there exists many different models falling in the class of mean-field models. They are well-understood analytically but also numerically where many methods exist to analyse them, namely the monte-carlo and the cavity method which are now essential numerical tools to investigate spin glass. At the same time, the renormalisation group technique which has been very useful in the past to analyse second order transition failed in many disordered systems to predict the behaviour of critical observables in non-mean-field spin glasses. We have chosen to study long-range interacting systems in which we don't know if the physics is identical to mean-field models. In a first part, we studied a ferromagnetic model on the Dyson hierarchical lattice. In this system with long-range interaction, we showed that it is easy to find a real-space transformation of the renormalisation group to compute the critical exponents. In a second part we focused on a spin glass model built on the same lattice. We made a first study where a real-space transformation is described for this system and we compare the estimations of the critical exponent nu for this model by different methods. The renormalisation group transformation gives some encouraging results but needs to be improved to become a more reliable method in this system. We have then investigated a model of random energies by using the same hierarchical topology. We studied numerically this system where we observed the existence of a phase transition of the same type as the one present in the REM of Derrida. However our model exhibits many different features compare to the REM. We found a non-analytical behaviour of the entropy at the transition and critical properties such as a diverging length-scale should occur according to our results. This last prediction has to be studied by a more direct measurement. By the numerical method we developed, we estimated the critical temperature using three different observables, all giving the same value. In the last part I turned to problems related to complex systems. It has been noticed recently that models of different fields such as physics, biology or computer science were very close to each other. This is particularly true in combinatorial optimisation problem which has been investigated using method of statistical physics. These techniques coming from the field of spin glasses and structural glasses were used to studied phase transitions in such systems and to invent new algorithms. We studied the problem of inference and learning of modular structure in random graphs by these techniques. We analysed the presence of topological clusters in some particular types of random graphs, and we showed that a phase transition occurred between a region where it is possible to detect clusters and a region where it is impossible. We also implemented a new algorithm using Belief Propagation to learn the properties of these clusters and to infer them in networks. We applied this algorithm to real-graph and discussed further development of this problem.

CO₂ injection in oil reservoirs provides the dual benefit of increasing oil recovery as well as sequestration. Compositional simulations using phase behavior calculations are used to model miscibility and estimate oil recovery. The injected CO₂, however, is known to react with brine. The precipitation and dissolution reactions, especially with carbonate rocks, can have undesirable consequences. The geochemical reactions can also change the mole numbers of components and impact the phase behavior of hydrocarbons. A Gibbs free energy framework that integrates phase equilibrium computations and geochemical reactions is presented in this dissertation. This framework uses the Gibbs free energy function to unify different phase descriptions - Equation of State (EOS) for hydrocarbon components and activity coefficient model for aqueous phase components. A Gibbs free energy minimization model was developed to obtain the equilibrium composition for a system with not just phase equilibrium (no reactions) but also phase and chemical equilibrium (with reactions). This model is adaptable to different reservoirs and can be incorporated in compositional simulators. The Gibbs free energy model is used for two batch calculation applications. In the first application, solubility models are developed for acid gases (CO₂ /H2 S) in water as well as brine at high pressures (0.1 - 80 MPa) and high temperatures (298-393 K). The solubility models are useful for formulating acid gas injection schemes to ensure continuous production from contaminated gas fields as well as for CO₂ sequestration. In the second application, the Gibbs free energy approach is used to predict the phase behavior of hydrocarbon mixtures - CO₂ -nC₁₄ H₃₀ and CH₄ -CO₂. The Gibbs free energy model is also used to predict the impact of geochemical reactions on the phase behavior of these two hydrocarbon mixtures. The Gibbs free energy model is integrated with flow using operator splitting to model an application of cation exchange reactions between aqueous phase and the solid surface. A 1-D numerical model to predict effluent concentration for a system with three cations using the Gibbs free energy minimization approach was observed to be faster than an equivalent stoichiometric approach. Analytical solutions were also developed for this system using the hyperbolic theory of conservation laws and are compared with experimental results available at laboratory and field scales. / text

Global economic trends suggest that there is a need to generate sustainable renewable energy to meet growing global energy demands. Solar energy harnessed by concentrated photovoltaic (CPV) systems has a potential for strong contributions to future energy supplies. However, as a relatively new technology, there is still a need for considerable research into the relationship between the technology and the solar resource. Research into CPV systems was carried out at the University of Ottawa’s Solar Cells and Nanostructured Device Laboratory (SUNLAB), focusing on the acquisition and assessment of meteorological and local solar resource datasets as inputs to more complex system (cell) models for energy yield assessment. An algorithm aimed at estimating the spectral profile of direct normal irradiance (DNI) was created. The algorithm was designed to use easily sourced low resolution meteorological datasets, temporal band pass filter measurement and an atmospheric radiative transfer model to determine a location specific solar spectrum. Its core design involved the use of an optical depth parameterization algorithm based on a published objective regression algorithm. Initial results showed a spectral agreement that corresponds to 0.56% photo-current difference in a modeled CPV cell when compared to measured spectrum. The common procedures and datasets used for long term CPV energy yield assessment was investigated. The aim was to quantitatively de-convolute various factors, especially meteorological factors responsible for error bias in CPV energy yield evaluation. Over the time period from June 2011 to August 2012, the analysis found that neglecting spectral variations resulted in a ~2% overestimation of energy yields. It was shown that clouds have the dominant impact on CPV energy yields, at the 60% level.