In this dissertation, an assessment is conducted of the potential benefits of combined heat and power (CHP) based district energy (DE) grids in energy systems of different scale having significant fossil fuel fired electrical generation capacity. Three studies are included in the research. In the first study, the potential benefits of expanding CHP-based DE grids in a large scale energy system are investigated. The impacts of expanding wind power systems are also investigated and a comparison between these technologies is made with respect to fossil fuel utilization and CO2 emissions. A model is constructed and five scenarios are evaluated with the EnergyPLAN software taking the province of Ontario, Canada as the case study. Results show that reductions in fuel utilization and CO2 emissions of up to 8.5% and 32%, respectively, are possible when switching to an energy system comprising widespread CHP-based DE grids. In the second study, a high temporal resolution numerical model (i.e. the SS-VTD model) is developed that is capable of rapidly calculating distribution losses in small scale variable flow DE grids with low error and computational intensity. The SS-VTD model is validated by comparing simulated temperature data with measured temperature data from an existing network. The Saanich DE grid, located near Victoria, Canada, is used as the case study for validation. In the third study, the potential benefits of integrating high penetrations of renewable energy via a power-to-heat plant in a small scale CHP-based DE grid are investigated. The impacts of switching to a CHP-based DE grid equipped with an electric boiler plant versus a conventional wave power system are compared with respect to fossil fuel utilization and CO2 emissions. The SS-VTD model is used to conduct the study. The energy system of the Hot Springs Cove community, located on the west coast of Vancouver Island, Canada is used as the case study in the analysis. Results show that relative to the conventional wave power system, reductions in fuel utilization and CO2 emissions of up to 47% are possible when switching to a CHP-based DE grid. / Graduate

Ma thèse en automatique s’inscrit dans la thématique de recherche «Transport» du LAMIH. L’objectif est d’améliorer le fonctionnement des moteurs thermiques (essence), notamment en réduisant la consommation et la pollution. Face à cet enjeu écologique et économique, et compte tenu des nouvelles normes et des stratégies court-termistes de l’industrie (scandale Volkswagen...), de nouveaux contrôleurs doivent être conçus pour piloter l’arrivée d’air et d’essence au sein du moteur. En considérant l’aspect hautement non-linéaire du système, la représentation Takagi-Sugeno et le background théorique du LAMIH sont utilisés. Un premier contrôleur est synthétisé pour régler le problème de la vitesse de ralenti du moteur. Cependant, la complexité du système impose l’utilisation d’un contrôleur très coûteux d’un point de vue computationnel. Un contrôleur alternatif est donc synthétisé afin d’être implémenté dans l’ordinateur embarqué du moteur. Un second contrôleur est obtenu pour maintenir la richesse en proportions stoechiométriques afin de réduire la pollution. Ce système étant sujet à un retard de transport variable, un changement de domaine est réalisé afin de rendre ce retard constant, et de concevoir un contrôleur simple et efficace. Des essais réels sur le banc d’essai moteur du LAMIH sont réalisés afin de valider la méthodologie présentée. / My PhD in Automatic Control is part of the research theme “Transport” of the LAMIH. The objective is to improve the functioning of the gasoline engines, mainly by reducing the fuel consumption and the pollution. With this ecologic and economic challenge, and taking into account the new norms and the short-term strategies of the industry (scandal of Volkswagen...), new controllers have to be designed to control the air valve and the fuel injection inside the engine. Considering the highly nonlinear aspect of the system, the Takagi-Sugeno representation and the theoretical background of the LAMIH have been used. A first controller is designed to solve the problem of idle engine speed. However, the complexity of the system forces the use of a controller that is very costly from a computational point of view. An alternative controller is then designed in order to be implemented inside the embedded computer of the engine. A second controller is obtained to maintain the air-fuel ratio in stoichiometric proportions in order to reduce the pollution. This system being subject to a variable transport delay, a change of domain is realized to make this delay constant, and to design a simple and efficient controller. Real-time experiments have been realized on the engine test bench of the LAMIH in order to validate the presented methodology.