Hydrogen is a by-product of the gasification process and it is environmentally friendly with respect to pollution and emission issues when it is derived from a CO2-neutral resource such as biomass. It is an energy carrier fuel and has flexibility to convert efficiently to other energy forms to be used in different energy applications like fuel cells. The proposed research presents literature on previous gasification studies regarding hydrogen production from biomass and updates the obtained results. The main objectives of the thesis are: a) to study hydrogen production via steam biomass (sawdust) gasification; b) to evaluate the produced hydrogen by performing comprehensive analysis by using thermodynamic, exergoeconomic and optimization analyses. Despite details specific to the gasifier, in general, there is a special need to theoretically address the gasifier that gasifies biomass to produce hydrogen. This further study of gasification aspects presents a comprehensive performance assessment through energy and exergy analyses, provides results of the optimization studies on minimizing hydrogen production costs, and provides a thermo-economic analysis for the proposed systems (Systems I, II and III). This thesis also includes the results from the performed study that aims to investigate theoretical hydrogen production from biomass (sawdust) via gasification technology. Results from the performed parametric study show that the gasification ratio increases from 70 to 107 gH2 per kg of sawdust. In the gasification temperature studied, system II has the highest energy efficiency that considers electricity production where it increases from 72 % to 82 % and has the lowest energy efficiency that considers hydrogen yield where it increases from 45 % to 55 %. Also, it has the lowest hydrogen cost of 0.103 $/kW-h. The optimization results show that the optimum gasification temperatures for System I, System II and System III are 1139 K, 1245 K and 1205 K, respectively. / UOIT

In the pilot plant at Hammarby Sjöstad, Sjöstadsverket, several new methods are tested in order to achieve a good use of resources. When a new technique is considered it is often the performance of the technique itself, under given conditions, that is evaluated. However, in order to evaluate the overall function the whole picture is needed. With a system analysis it becomes possible to make a comparison where all the positive aspects are put up against the negative ones, for the technique itself as well as its requirements. In this way the influence that minor components have on an entire system can be considered. This report presents a system analysis of an anaerobic membrane reactor (MBR) with a VSEP-membrane (Vibratory Shear Enhanced Process). The MBR is tested at the research treatment plant at Hammarby Sjöstad. In the analysis presented two different treatment techniques treating two different types of wastewaters are compared. The considered techniques are conventional (represented by an active sludge process) and the MBRtechnique. The waters treated are a mixed wastewater and wastewater from a separating system where closet water is separated from greywater and mixed with food waste from waste disposers. The system analysis has been carried out with the URWARE (URban WAter REsearch) system analysis tool. A new URWARE-model that describes the anaerobic reactor and the VSEP membrane was created in order to generate the system structures needed for the analysis. The model consists of two submodels, which as the other URWARE-models are mass-flow, steady-state models based on yearly average-values. The model was tested and calibrated from the test-results at the Hammarby Sjöstad pilot plant. In the study the systems are compared considering energy, exergy and recirculation of nutrients. The VSEP-technique has some advantages compared to the conventional system as it ensures that a large part of the nutritional content in the wastewater can be retained. The advantage is more obvious with the separated system, where food waste is mixed with closet water. Also the global warming potential of the new technique is lower. However, conventional treatment is better from an exergy-perspective. This is mostly due to the high energy consumption as a result of the reversed osmosis (RO) required for post treatment. / I försöksanläggningen vid Hammarby Sjöstad, Sjöstadsverket undersöks flera olika metoder för att uppnå största möjliga resursutnyttjande. När en ny teknik utprovas är det i allmänhet funktionen hos den givna metoden under givna förutsättningar som undersöks. För att få ett helhetsperspektiv krävs emellertid att den sätts in i sitt sammanhang. En systemanalys gör det möjligt att få en bild av alla för- och nackdelar, såväl av tekniken i sig som av de förutsättningar den kräver. Även effekter som små delar har på ett helt system kan då belysas och dess betydelse för helheten fastställas. Föreliggande studie möjliggör en systemanalytisk utvärdering av en anaerob membranbioreaktor (MBR) kopplad till ett VSEP-membran (Vibratory Shear Enhanced Process) som är under utprovning vid Sjöstadsverket. Studien jämför två vattenreningstekniker för behandling av två olika typer av avloppsvatten. Dels rör det sig om konventionell teknik (aktiv slam-rening liknande den behandlingsmetod som används idag), dels den nya MBRtekniken. De vatten som behandlas är blandat avloppsvatten respektive sorterat klosettvatten blandat med matavfall från avfallskvarnar. Systemanalysen har utförts med hjälp av systemanalysverktyget URWARE (URban WAter REsearch). För att kunna bygga upp önskade systemstrukturer har en ny modell för att beskriva den anaeroba reaktorn och VSEP-membranet skapats inom ramen för detta examensarbete. Modellen består av två delmodeller, som liksom övriga modeller i URWARE är substansflödesmodeller där beräkningar är baserade på årsmedelvärden. Modellen har utprovats och kalibrerats mot mätresultat från pilotförsöken vid Sjöstadsverket. I studien jämförs systemen med avseende på energi, exergi och återföring av närsalter. Utifrån systemanalysen konstateras att MBR-tekniken ger vissa fördelar gentemot konventionell teknik då en stor del av näringsinnehållet från avloppsvattnet kan fångas upp. Detta gäller speciellt då tekniken används i kombination med ett separerat avloppssystem där matavfall blandas med klosettvatten. Även växthuspotential för den nya tekniken är lägre totalt sett. Ur exergisynpunkt är konventionell teknik emellertid mer fördelaktig. Till stor del beror detta på hög energiförbrukning pga. den efterbehandling med omvänd osmos (RO) som systemet i dess nuvarande utformning kräver.

Wärmespeicher tragen bei optimierter Integration in Wärme- und Kälteversorgungsanlagen zur Einsparung von installierter Erzeugerleistung, Brennstoffeinsatz und Betriebskosten bei. Leider treten in Wärmespeichern oft noch beachtliche Verluste auf und das Potenzial zur Kosten- und Energieeinsparung wird nicht vollständig ausgeschöpft. Dabei spielen nicht nur Wärmeverluste an die Umgebung, sondern vor allem auch innere Verluste im Speicher eine Rolle. Schwerpunkte der vorliegenden Arbeit sind die Beschreibung der einzelnen Verluste an Wasserwärmespeichern, die Ermittlung ihrer Ausmaße abhängig von der konstruktiven Gestaltung und der Betriebsweise des Speichers sowie die Auswirkungen der Verluste auf einen vorgelagerten Wärmeerzeuger und den Einsatz von Primärenergie. Die Ergebnisse basieren auf umfangreichen Speichermodellierungen mit dem CFD-Code Fluent sowie experimentellen Untersuchungen an drei Testspeichern. Der quantitative Vergleich der Verluste für ausgewählte Beispiele zeigt bestehende Defizite sowie die Potenziale für die Verbesserung der Konstruktion neuer Wasserwärmespeicher auf. / If hot water storage tanks are optimally integrated in heat or cold supply systems, they contribute to a reduction of required capacity, fuel and operation costs. Unfortunately, even today remarkable heat losses and internal losses occur in hot water storage tanks. The potential for cost and energy reductions is not completely utilized yet. Here, not only heat losses to the ambience, but also internal losses play a decisive role. Main focus of the presented work is the description of the single losses at hot water storage tanks and the determination of the correlation between the losses, the tank design and the mode of operation. Furthermore the effects of the losses in the tank on the efficiency of different types of heat generators and the input of primary energy into the system have been examined. The results are based on extended numerical modeling with the CFD-code Fluent as well as experimental test with three storage tanks. The quantitative comparison of the losses for selected examples shows the current shortcomings but even the potential for an optimized hot water storage tank design.

D. Tech. Electrical Engineering. / Discusses the objectives of thesis in terms of : 1. To formulate and integrate models for the wind-turbine, induction generator, PV array, battery, supercapacitor, and power electronic converters in a form suitable for studying the dynamic behaviour of the microgrid; 2. To develop an online optimisation algorithm and use it to optimise local control algorithms for PV array, energy storage system, and the doubly fed induction generator. 3. To formulate an efficient power sharing strategy between battery and supercapacitor. 4. To implement an overall control system which sets the power reference for the energy storage system and ensures that the requested power demand is supplied to the grid.

Nowadays, office buildings often have large temperature variations during the day and building envelope acts as an energy storing mass and damp these effects and so Offices need more cooling because of internal heat sources. But we know that cooling is more expensive than heating and it uses the very good quality of energy sources (exergy). Controlled Active Mass (CAM) is new approach to absorb radiant heating and acts as a passive cooling device. It has direct cooling effect and reduces the peak load. CAM is a new cooling system design with applying the low energy sources and operates at water temperature close to room temperature and increase the efficiency of heat pumps and other systems. In this project, we calculated the transient heat transfer analysis for CAM in a very well insulated test room with façade wall, Internal heat generators (such as Manikin, Computer simulator & lighting) and ventilation. Then Polished (shiny) CAM constructed from Aluminum sheets with 0.003 m thickness. It is cube shape with 0.6 m length. This size of CAM is according to 2.5 times larger than human body volume and initial water temperature assumed near half of human body temperature. Then in order to more radiation damping (absorption) by CAM, it painted black (also based on color analysis in heat transfer calculation). Some velocity and temperature measurement have been carried out on both polished CAM and black CAM, after visualization by smoke and Infrared Camera. And more cases tested to see the effect of façade wall, IHG’s and ventilation inlet temperature. Thermal comfort measurement also have been done for finding PMV, PPD and temperature equivalent for a seated person which is doing an office job with normal closing. At the end results discussed which includes the effect of CAM in room, differences between polished CAM and black CAM and effect of main heat sources on both CAM types (Polished / Black).

Dans les turbomachines conventionnelles, l’estimation des performances (rendement, puissance et rapport de pression) se fait en général en admettant l’adiabaticité de l’écoulement. Mais, de nombreuses études ayant montré l’influence négative des échanges thermiques internes et externes sur les performances des petites turbomachines dans les faibles charges et aux bas régimes, cette hypothèse ne peut plus être recevable. L’objectif principal de cette thèse est de contribuer à lever l’hypothèse d’adiabaticité.Une étude préalable de l’état de l’art a permis de relever les différents types de transferts thermiques dans les turbomachines et de circonscrire notre étude.Puis, une analyse exergétique généralisée, ayant pour but la prise en compte des deux principes de la thermodynamique, a été effectuée et l’évolution de l’indice de performance caractérisant le niveau d’énergie récupérable en fonction des échanges thermiques est étudiée.Les performances des turbomachines à fluide compressible sont généralement représentées sous forme graphique dans des systèmes de coordonnées adimensionnelles établies avec l’hypothèse d’adiabaticité. Ces cartographies couramment utilisées par les exploitants et constructeurs ne conviennent pas aux machines fonctionnant avec transferts thermiques. L’étude de la similitude des turbomachines thermiques à fluide compressible présentée dans ce travail, propose de nouvelles coordonnées adimensionnelles pouvant être utilisées aussi bien en adiabatique que dans les écoulements avec transferts thermiques.Enfin, nous proposons un protocole de mesures et un modèle numérique pour l’évaluation des transferts thermiques dans un turbocompresseur.Certains résultats obtenus montrent que les performances calculées avec l’hypothèse d’adiabaticité de l’écoulement du fluide sont surestimées. Les nouvelles lois de la similitude proposées généralisent le théorème de Rateau au fluide compressible fonctionnant dans n’importe quelle condition et permettent de calculer les échanges thermiques à chaud à partir des résultats d’essai à froid. Une donnée supplémentaire (température de refoulement) est néanmoins nécessaire pour la prédiction complète des performances et des échanges thermiques.Le modèle numérique de calcul des échanges thermiques proposé donne des résultats en accord avec ceux attendus, mais nécessite des données réelles issues de mesure sur banc pour une validation complète. / In the conventional turbomachines, calculations are done assuming adiabatic flow. But, the negative influence of external and internal heat exchange on the performance of small turbomachines at low loads and low speeds have been shown by many studies in the literature. Then, this assumption is no longer admissible. The main objective of this thesis is to help remove the assumption of adiabaticity.A study of the state of art has identified the different kinds of heat transfer and defined the limits of our investigations.Afterwards, a generalized exergy analysis whose main goal is to take into account the two principles of thermodynamics has been made and the variation of exergy performance versus heat transfer has been studied.The maps currently used are made with the assumption of adiabaticity. The laws of similarity in turbomachines working with compressible fluid studied propose new dimensionless coordinates that can be used in any operating condition (adiabatic or not).Finally, we present a measurement protocol and a numerical model for calculating heat transfer in a turbocharger.Some results from our work indicate that the performance of thermal turbomachinery announced regardless of thermal heat exchanges are found to be overestimated.The new laws of similarity proposed generalize the Rateau’s theorem to compressible fluid flow in any operating condition and can be used to calculate heat transfer from adiabatic test results. Supplementary information is still required for the complete prediction of performance and heat transfer.The numerical model for calculating heat transfer gives some results that are in agreement with those expected. But actual data from test bench are required for complete validation.

This thesis puts forth the means of a strategic approach to address a persistent problem in the energy system and in this way, to transition the built environment to a future state that is more exergy-aware to curb CO2 emissions. Such a vision is made possible by the six-fold contributions of the research work: I) An analytical model is developed, which for the first time, formulates the CO2 emissions that are compounded in the energy system as a function of the systematic failures to match the supply and demand of exergy. This model is namely the Rational Exergy Management Model or REMM. II) REMM is then applied to analyze the pathways in which it is possible to lead the built environment into addressing structural overshoots in its exergy supply to curb CO2 emissions. The cases that embody these pathways are also analyzed over a base case, including cases for sustainable heating and cooling. III) New tools are designed to augment decision-making and exemplify a paradigm shift in the more rational usage of exergy to curb CO2 emissions. These include a scenario-based analysis tool, new options for CO2 wedges, and a multi-fold solution space for CO2 mitigation strategies based on REMM. IV) The concept of a net-zero exergy building (NZEXB) is developed and related to REMM strategies as the building block of an exergy-aware energy system. The target of a NZEXB is further supported by key design principles, which address shortcomings in state-of-the-art net-zero design. V) A premier building that deployed the key design principles to integrate building technology in an innovative, exergy-aware design and received LEED Platinum is analyzed on the basis of the NZEXB target. The results validate that this building boosts net self-sufficiency and curbs compound CO2 emissions, which are then presented in a proposed scheme to benchmark and/or label future NZEXBs. VI) Based on the scalability of the best-practices of the NZEXB ready building, the means to realize a smarter energy system that has exergy-aware relations in each aspect of the value chain to curb CO2 emissions are discussed. This includes a target for such a network at the community level, namely a net-zero exergy community (NZEXC). As a whole, the results of the thesis indicate that the strategic approach as provided by REMM and the NZEXB target of the research work has the potential to steer the speed and direction of societal action to curb CO2 emissions. The thesis concludes with a roadmap that represents a cyclical series of actions that may be scaled-up at various levels of the built environment in a transition to be in better balance with the Planet. / QC 20111014

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-14T11:05:38Z No. of bitstreams: 1 FERNANDO JOSÉ DA SILVA - TESE (PPGEP) 2014.pdf: 7661090 bytes, checksum: d6d7296ae6b4537cc796b5ad44bc0b46 (MD5) / Made available in DSpace on 2018-09-14T11:05:38Z (GMT). No. of bitstreams: 1 FERNANDO JOSÉ DA SILVA - TESE (PPGEP) 2014.pdf: 7661090 bytes, checksum: d6d7296ae6b4537cc796b5ad44bc0b46 (MD5) Previous issue date: 2014-02-24 / CNPq / O combustível gasoso (gás natural) tem sido muito utilizado em motores diesel nos últimos anos, devido suas características positivas quando o foco é o nível das emissões lançadas na atmosfera. O biodiesel; combustível renovável, tem se apresentado como potencial alternativo para contribuir com a redução das emissões poluentes no mundo, com propriedades comparáveis ao diesel, tem sido usado amplamente em motores do ciclo diesel. O desafio é utilizar o motor diesel que opere de forma dual (líquido/gás), com misturas adequadas de diesel, biodiesel e gás natural, para obter a proporção correta de cada combustível, mantendo as características originais do motor e bom desempenho. Neste sentido, o objetivo desta pesquisa é analisar o desempenho, as características das emissões de um motor diesel, trabalhando com diesel comercial B5, biodiesel e gás natural. O combustível utilizado no motor consiste na mistura de 15% de óleo diesel e biodiesel (combustível líquido) e 85% de gás natural. Experimentos foram realizados em potências de 40, a 120 kW, com intervalos de 20 kw. O motor foi instrumentado para obter temperatura, fluxos de massa de ar, gás, diesel e biodiesel, pressão do ar de entrada do motor, do óleo lubrificante e concentração dos gases de combustão durante cada teste experimental. O custo específico do motor operando no modo dual foi melhor do que no modo diesel e a mistura diesel, biodiesel e gás natural que apresentou o menor custo específico, foi a mistura B50. Verificou-se a partir dos resultados experimentais que as emissões de NOx, NO e CO2 diminuíram, enquanto que as emissões de CO aumentaram, quando comparadas com a condição do motor operando no modo diesel comercial B5 como único combustível. / The gaseous fuel (Natural Gas) has been widely used on diesel engines in the last few years, due to its positive characteristics as far as the level of emissions released in the atmosphere is concerned. Biodiesel has been considered a potential alternative to contribute to reducing pollutant emissions level in the world, as a renewable fuel, its properties are comparable to the one of the diesel fuel which is already widely used in diesel engines. The big challenge is to use the diesel engine which operates in a dual form, using adequate mixtures of diesel, biodiesel and natural gas to obtain the correct proportion of each fuel and maintaining the original characteristics of the engine as well as a good performance. In this sense, the aim of this research is to study the characteristics of the commercial diesel engine emissions, operating with B40, B50, B60 and natural gas. The fuel used in the engine consists of a mixture of 15% diesel and biodiesel (liquid fuel) and 85% natural gas. Experiments were made using 40, to 120 kW, with an interval of 20 kW. The engine was instrumented to obtain the temperature, air, gas, diesel and biodiesel flow rate, the air pressure at the entrance of the engine, the lubricant oil temperature, and the concentration of exhaust gases during each experimental test. The specific cost of the engine operating in dual mode was better than in diesel mode, and the blend of diesel, biodiesel and natural gas with the lowest specific cost was the B50 blend. It was verified that the emission of NOx, NO and CO2 had decreased while the emissions of CO had increased, when compared to the conditions using commercial diesel (B5) as the only fuel.

Dans un contexte de réduction des émissions de gaz à effet de serre (GES) et de forte volatilité du prix des énergies, les investissements en efficacité énergétique des sites industriels résultent souvent d'un processus de décision complexe. L'industriel doit pouvoir disposer d'outils lui permettant d'élaborer les solutions d'efficacité énergétique envisageables sur son site. Outre la recherche des sources d'énergie alternatives, que sont les énergies renouvelables, qui n'atteindront leur maturité technologique que sur le long terme, une solution à court terme consiste plutôt à favoriser une utilisation plus rationnelle de l'énergie. Pour relever ce défi, l'analyse exergétique apparaît comme un outil très efficace, car elle permet d'identifier précisément les sources d'inefficacité d'un procédé donné et de proposer des solutions technologiques visant à y remédier. Malheureusement, contrairement au concept d'enthalpie traditionnellement utilisé pour réaliser des bilans énergétiques sur un procédé, ce concept demeure assez difficile à appréhender et n'est que très rarement implémenté dans les simulateurs de procédés. Les travaux présentés dans ce document visent d'abordà rendre l'analyse exergétique plus accessible en l'intégrant dans un simulateur de procédés, puis à démontrer la pertinence d'une telle analyse pour l'amélioration de l'efficacité des procédés et des utilités associées. Dans un premier temps, une formulation générique et indépendante du choix du modèle thermodynamique pour l'évaluation de l'exergie des flux de matière est introduite. Une méthode de calcul des différentes contributions de l'exergie (contributions thermique, mécanique et chimique) est développée et un nouveau concept visant à évaluer les potentiels de récupérations thermique et mécanique maximales est introduit. Par la suite, la notion de bilan exergétique sur un système donné (opération unitaire ou procédé complet) est introduite. Pour l'évaluation des exergies des flux de travail et de chaleur, deux cas de figure sont étudiés : le cas de l'amélioration de procédés existants (« retrofitting ») et le cas de la conception de nouveaux procédés (« design»). Dans le cas de l'amélioration de procédés existants et afin d'aider au diagnostic énergétique de ces systèmes, des tableaux synthétiques proposant des solutions technologiques visant à réduire les irréversibilités ou les pertes exergétiques externes du procédé sont proposés. Par ailleurs, après une analyse comparative des différentes formulations d'efficacité exergétiques existant dans la littérature, la notion d'efficacité intrinsèque est retenue comme le critère le plus adapté pour une optimisation de l'efficacité exergétique d'un procédé complexe. Enfin, une nouvelle méthodologie structurée dédiée à l'analyse exergétique et permettant de pallier les lacunes des méthodologies existantes est présentée. L'ensemble de ces concepts est implémenté dans un premier prototype logiciel écrit en langage VBScript et intégré au simulateur de procédés ProSimPlus. Enfin, l'efficacité de la procédure est démontrée à travers une étude de cas portant sur la production de gaz naturel. / Energy issue is becoming increasingly crucial for industrial sector that consumes large quantities of utilities. Although the scientific world should continue to look for alternate sources of energy, a short-term solution would rather rely on a more rational use of energy. To face this challenge, exergy analysis appears a very efficient tool as it would enable to increase efficiency and reduce environmental impact of industrial processes. Unfortunately, contrary to enthalpy, this concept is rather difficult to handle and exergy analysis is rarely implemented in process simulators. In this context, the major objective of the study presented in this dissertation is to make exergy analysis more understandable by coupling it with the use of a process simulator and also to demonstrate the value of this approach for analysis of energy efficiency of processes and utilities. This dissertation presents a generic formulation for exergy of material streams that does not depend on the thermodynamic model, so that it could be easily implemented in a process simulator. The different contributions of exergy (thermal, mechanical and chemical) have been developed and new concept such as the maximal thermal and mechanical recovery potential has been introduced in order to pave the way for exergy analysis. The formulations of exergy balances on a real process are presented. For that purpose, the formulation of exergy for heat and work flux is developed. The formulation of exergy balances has been introduced for both design and retrofit situations and then a set of hints for the interpretation of this exergy balance has been given. Synthetic tables providing solutions to reduce irreversibilities and external losses have been introduced. Moreover, different kinds of exergy efficiency have been defined to provide a new criterion for the optimization of the process. A new structured methodology for exergy analysis is developed to overcome the limitations of existing methodologies. To make exergy analysis easier for any engineer, a first prototype has been developed to implement the calculation of exergy for the material streams in a process flowsheet modeled in ProSimPlus. Thanks to this prototype, exergy of each material stream appears in a synthesis table next to the traditional thermodynamic values such as the enthalpy. Finally, a case study on Natural Gas Liquids recovery process is presented to demonstrate the benefit of the exergy analysis for the improvement of existing processes. First, the exergy analysis permits to make an energy diagnosis of the process: it pinpoints the inefficiencies of the process which relies not only on irreversibilities but also on external exergy losses. Then, based upon respective values of internal and external losses and also thanks to the breaking down of exergy into it thermal, mechanical and chemical contributions, some technological solutions are suggested to propose a retrofit process. Finally, the exergy efficiency criteria enable to optimize the operating parameters of the process in order to improve its energy efficiency.

A la veille d’une nouvelle conférence sur le climat, les questions environnementales demeurent plus que jamais au premier plan de la vie publique. La lutte contre le réchauffement climatique, et les émissions de gaz à effet de serre, dont l’attribution à l’activité humaine fait globalement l’objet d’un consensus scientifique, constituent l’un des plus grands défis de l’humanité pour les prochaines années. Dans ce contexte, l’amélioration de l’efficacité énergétique des sites de production est une des préoccupations des industriels. Les réglementations environnementales, et les fluctuations des cours de l’énergie les forcent à continuellement améliorer leurs procédés pour en maintenir la compétitivité. Ceux-ci doivent ainsi pouvoir disposer d’outils leur permettant d’effectuer des diagnostics énergétiques sur les installations, leur facilitant la prise de décision et leur permettant d’élaborer des solutions d’efficacité énergétique sur leurs sites industriels. Les travaux présentés dans ce document visent à introduire une méthodologie d’analyse et de rétro-conception pour l’amélioration énergétique des procédés industriels. Cette méthodologie, qui s’appuie sur une utilisation combinée de la méthode du pincement et de l’analyse exergétique, se décompose en trois grandes étapes : la première comprend le recueil des données, la modélisation et la simulation du procédé. La deuxième étape, dédiée à l’analyse du procédé, est elle-même divisée en deux phases. La première, qui s’appuie pour l’essentiel sur l’utilisation de la méthodologie du pincement, s’intéresse uniquement à l’analyse du système de fourniture et de récupération de l’énergie thermique. Si cela s’avère nécessaire, le procédé complet est étudié dans une deuxième phase. L’analyse pincement se limitant à l’étude des procédés thermiques, une méthodologie d’analyse exergétique est mise en œuvre. Cette méthodologie s’appuie sur l’implémentation de l’analyse exergétique dans l’environnement ProSimPlus, entreprise par Ali Ghannadzadeh, et poursuivie pendant cette thèse. Les formules d'exergie ont été affinées pour s’ajuster aux différents modèles thermodynamiques. L’approche d’analyse proposée dans ce manuscrit est basée sur l’utilisation d’une nouvelle représentation graphique des bilans exergétiques : le ternaire exergétique. Ce dernier permet d’illustrer tous les aspects des bilans exergétiques et ainsi d'assister l’ingénieur dans l’analyse du procédé. La troisième étape s’intéresse à la conception pour l’amélioration énergétique. Alors que l’analyse du pincement propose des solutions d’amélioration, l’analyse exergétique ne le permet pas. Elle nécessite l’apport d’une certaine expertise pour aboutir au développement de solutions d’améliorations. Pour pallier ce problème, l’expertise est en partie capitalisée dans un système de raisonnement à partir de cas. Ce système permet de proposer des solutions à des problèmes nouveaux en analysant les similarités avec des problèmes anciens. Cet outil se révèle utile pour définir des solutions locales d’améliorations énergétiques. L’analyse du pincement associée à des outils numériques est ensuite utilisée pour concevoir des propositions complètes d’améliorations. La seconde partie de ce manuscrit présente cette étape. / On the eve of a new conference on climate change, environmental issues remain more than ever at the forefront of public life. Tackling climate change, and reducing greenhouse gases emissions, that are largely attributable to human activity, represents one of the biggest challenges for humanity in the coming years. In such a context, the promotion of best practices to enable an efficient utilization of energy has emerged as one of the major point of focus. High volatility of energy prices and the increasingly stringent environmental regulations have forced industrials to continuously improve their processes in order to cut the energy consumption down and reduce GHG emissions. For this purpose, industrials need tools to perform energy audits on facilities, to ease decision-making and to enable them to develop their energy efficiency solutions on their sites. In this context, the study presented in this dissertation aims at introducing a new systematic procedure for energy diagnosis and retrofit of industrial processes. This methodology presented in this dissertation is divided into three stages: the first involves the data collection, the modeling and simulation of the process. The second stage, dedicated to the analysis of the process, is subdivided into two phases. The first, which is essentially relying on the Pinch methodology, is only concerned with the analysis of the thermal energy supply and recovery system. If necessary, the complete process is studied in the second phase of the analysis. Pinch analysis being limited to the analysis of thermal systems, an exergy analysis methodology is then implemented. This methodology is based on the implementation of the Exergy analysis in the ProSimPlus modelling and simulation environment, undertaken by A. Ghannadzadeh, and pursued in this study. The formulas proposed by Ali Ghannadzadeh have been adjusted to take into account different thermodynamic approaches. A new graphical representation of exergy balances, the exergetic ternary diagram, is also introduced to assist engineers in the analysis process. It enables to illustrate all aspects of exergy balances, i.e. the irreversibility, the exergy losses and the exergy efficiencies of each unit operation. The automation of this new graphical layout was made possible by the implementation of a generic exergy efficiency in the simulator. This analysis paves the way to the third step of the overall methodology dedicated to retrofitting. This methodology is detailed in the first part of this dissertation. While Pinch analysis proposes improvement solutions, the Exergy analysis does not. The key to achieving a significant exergy analysis lies in the engineer’s ability to propose alternatives for reducing thermodynamic imperfections, thus exergy analysis is supposed to be undertaken by an experienced user. To overcome this problem, the expertise is partly capitalized in a case-based reasoning system. This system allows the proposition of solutions to new problems by analyzing the similarities with solved problems. This tool is useful for defining local solutions for energy improvements. The Pinch analysis combined to numerical tools is then used to develop alternatives. This third step is developed in the third part of the manuscript.