A significant part of world energy consumption balance, approx. 40 %, is utilized in buildings. Maintenance of comfortable conditions and improvement in the living, working or recreational environment is a desire for every human. Therefore it is no surprise that there has been a sudden increase in scientific research in the field of building’ energy efficiency. Despite the relevance of the problem there is no sustaining methodology for evaluating building’ energy efficiency by applying sustainable energy development approach. The majority of the researchers don’t assess different potential of the analyzed energy flows nor systems operational regimes. The aim of the work is to evaluate the possibilities for applying exergetical process and system integration method in the design, operation and normalization of the office building service systems: to prepare design solutions that increase buildings’ service systems’ thermodynamical efficiency and covers individual processes and elements’ chain systems. The thesis is divided into the introduction and three main chapters, conclusions, a list of literature and a list of publications. In this work the building service systems’ analysis incorporates three interconnected methods: system analysis, life cycle and thermodynamical analysis. Application of system analyses enables an estimation of service system’s elements (subsystems) and their interconnections. Life cycle analysis allows estimation of total exergy demand through the... [to full text] / Ženklią dalį pasauliniame galutinės energijos vartojimo balanse, apie 40 %, užima energijos dalis, suvartojama pastatuose. Komfortinių sąlygų palaikymas ir gerinimas gyvenamojoje, darbo ar poilsio aplinkoje yra natūralus kiekvieno žmogaus poreikis. Pastaruoju metu stebimas ryškus mokslinių tyrimų suaktyvėjimas didininat energijos vartojimo pastatuose efektyvumą. Nepaisant aktualios problematikos, nuoseklios, darnia energetikos plėtra grindžiamos pastatų energetinio efektyvumo vertinimo metodikos iki šiol nėra. Daugelio tyrėjų naudojami metodai neįvertina skirtingų analizuojamų energijos srautų kokybinių potencialų, nekreipiamas dėmesys į skirtingus sistemų veikimo režimus jų eksploatavimo metu. Darbo tikslas – įvertinti galimybes taikyti procesų ir sistemų integracijos metodą viešųjų pastatų mikroklimato sistemų projektavime, naudojime bei normavime, sukuriant individualius procesus ir visą įrenginių sistemą aprėpiantį priemonių kompleksą, kurio dėka būtų padidintas energijos vartojimo pastate termodinaminis naudingumas. Disertaciją sudaro įvadas, 3 skyriai, pagrindinės išvados, naudotos literatūros sąrašas. Disertaciniame darbe pastato inžinerinių sistemų tyrimui panaudoti trys metodai: sisteminė analizė, gyvavimo ciklo analizė ir termodinaminė (ekserginė) analizė. Sisteminės analizės naudojimas leidžia apibrėžti pastato inžinerinių sistemų elementus bei jų tarpusavio ryšius. Pasitelkus gyvavimo ciklo analizę nustatomi eksergijos poreikiai per visą sistemos gyvavimo... [toliau žr. visą tekstą]

The dissertation investigates the issues of efficient energy use in building engineering systems possibilities by applying processes integration. Indoor climate formation systems are indicated as signally energy use building engineering systems. Traditional methods for evaluation of heat transfer in heat exchangers tender limited solutions for efficiency use of energy in them. The main object of dissertation is to evaluate processes integration method application possibilities for determination and improving of public buildings engineering systems. The dissertation also focuses on combine the possibilities of processes integration in building engineering systems with minimizing exergy streams in the systems. The paper approaches a few major tasks: determination of problematic building engineering systems, equipment and processes by viewpoint of energy efficiency, analysis of ventilation design solutions, creation of algorithm for exergy input minimizing in building engineering systems processes by combination of thermodynamical and Pinch analysis methods. The dissertation consists of four parts including Introduction, 4 chapters, Conclusions and References. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the paper, research methodology, scientific novelty, the practical significance of results examined in the paper and defended statements. The introduction ends in presenting the... [to full text] / Disertacijoje nagrinėjamos procesų integracijos metodo taikymo galimybės sprendžiant efektyvaus energijos vartojimo pastatų inžinerinėse sistemose problemas. Tarp pastato inžinerinių sistemų darbe išskiriamos ženkliau energiją naudojančios, mikroklimatą pastatuose formuojančios sistemos. Klasikiniai tyrimo metodai, skirti šilumos mainams šilumokaičiuose, kurie atlieka šilumos perdavimo funkciją, nagrinėti pateikia gana ribotus sprendinius, kaip efektyviai naudoti energiją juose. Pagrindinis disertacijos tikslas – įvertinti procesų integravimo metodo taikymo galimybes viešųjų pastatų inžinerinių sistemų termodinaminiam efektyvumui nustatyti ir gerinti. Disertacijoje taip pat siekiama derinti procesų integracijos galimybes inžinerinėse sistemose siekiant minimizuoti eksergijos srautus jose. Darbe sprendžiami keli pagrindiniai uždaviniai: probleminių, energinio efektyvumo požiūriu, pastato inžinerinių sistemų, įrenginių ir procesų jose nustatymas, vėdinimo sistemų projektinių sprendimų ypatybių nustatymas, algoritmo, skirto procesų eksergijos sąnaudoms mažinti pastato inžinerinėse sistemose sudarymas derinant termodinaminės ir Pinch analizės metodus. Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autorės publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas... [toliau žr. visą tekstą]

Disertacijoje nagrinėjamos procesų integracijos metodo taikymo galimybės sprendžiant efektyvaus energijos vartojimo pastatų inžinerinėse sistemose problemas. Tarp pastato inžinerinių sistemų darbe išskiriamos ženkliau energiją naudojančios, mikroklimatą pastatuose formuojančios sistemos. Klasikiniai tyrimo metodai, skirti šilumos mainams šilumokaičiuose, kurie atlieka šilumos perdavimo funkciją, nagrinėti pateikia gana ribotus sprendinius, kaip efektyviai naudoti energiją juose. Pagrindinis disertacijos tikslas – įvertinti procesų integravimo metodo taikymo galimybes viešųjų pastatų inžinerinių sistemų termodinaminiam efektyvumui nustatyti ir gerinti. Disertacijoje taip pat siekiama derinti procesų integracijos galimybes inžinerinėse sistemose siekiant minimizuoti eksergijos srautus jose. Darbe sprendžiami keli pagrindiniai uždaviniai: probleminių, energinio efektyvumo požiūriu, pastato inžinerinių sistemų, įrenginių ir procesų jose nustatymas, vėdinimo sistemų projektinių sprendimų ypatybių nustatymas, algoritmo, skirto procesų eksergijos sąnaudoms mažinti pastato inžinerinėse sistemose sudarymas derinant termodinaminės ir Pinch analizės metodus. Disertaciją sudaro įvadas, keturi skyriai, rezultatų apibendrinimas, naudotos literatūros ir autorės publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas... [toliau žr. visą tekstą] / The dissertation investigates the issues of efficient energy use in building engineering systems possibilities by applying processes integration. Indoor climate formation systems are indicated as signally energy use building engineering systems. Traditional methods for evaluation of heat transfer in heat exchangers tender limited solutions for efficiency use of energy in them. The main object of dissertation is to evaluate processes integration method application possibilities for determination and improving of public buildings engineering systems. The dissertation also focuses on combine the possibilities of processes integration in building engineering systems with minimizing exergy streams in the systems. The paper approaches a few major tasks: determination of problematic building engineering systems, equipment and processes by viewpoint of energy efficiency, analysis of ventilation design solutions, creation of algorithm for exergy input minimizing in building engineering systems processes by combination of thermodynamical and Pinch analysis methods. The dissertation consists of four parts including Introduction, 4 chapters, Conclusions and References. The introduction reveals the investigated problem, importance of the thesis and the object of research and describes the purpose and tasks of the paper, research methodology, scientific novelty, the practical significance of results examined in the paper and defended statements. The introduction ends in presenting the... [to full text]

Models showing the anthropogenic and natural flows of two sustainability indicators; carbon based GHG and energy (as work energy) have been made for the Swedish region Jämtland. The methodology used was inspired by the study sustainability analysis conducted on the small Danish island Samsø using the above two indicators. The aim was to upscale the methodology used for Samsø and make necessary adaptations for Jämtland in order to be able to evaluate sustainability in terms of global warming. We also wanted to study the linkages between research, education and regional sustainability initiatives. Working at a regional level has advantages compared to working at a national or global level, as socio-ecological processes can be covered more extensively to reach a deeper understanding of practical aspects. In parallel to this we have also been participating in local and regional sustainability activities to increase our understanding of practical approaches and human behaviour. Studies of the energy flows in Jämtland show that 46,000 TJ (88% renewable) flows into the region and about 31,000 TJ is exported. The remaining 15,000 TJ (63% renewable) drives ‘the machine Jämtland’. Added to this is about 4000TJ as matter. The total global warming potential (GWP20) impact of Jämtland (as carbon dioxide equivalents, CO 2eq ) indicating influence on the global mean temperature as radiative forcing) is an annual uptake of 2.4 Mton. The total regional emissions, as CO 2eq, from anthropogenic activities, including consumption, are 1500 kton. The region has large emissions of methane, 80kton (6700 kton CO 2eq ), mainly from mires, lakes and animals but also large uptakes of CO2 from assimilation in woody biomass. Jämtland can be regarded as relatively sustainable from several perspectives, but taking the large forests and a population of only 127,000 inhabitants into consideration, the total uptake of CO 2eq is not very large and of the 15,000 TJ driving Jämtland, 37% comes from non-renewable sources. From a national (and global) perspective Jämtland needs to perform better, in view of its considerable reserves of natural resources. How to increase long-term sustainability in the region is a complex issue that requires penetration from many perspectives. Modelling results presented here needs to be interpreted in a broader sustainability context, together with regional stakeholders, to serve as a base for future knowledge development and sustainability activities. / Två modeller har utvecklats för att studera antropogena och naturliga flöden av energi (exergi) och kolbaserade växthusgasflöden i Jämtland. Metodiken har inspirerats av en metodik för att göra hållbarhetsanalyser som genomförts för den lilla danska ön Samsø utifrån dessa båda indikatorer. Att arbeta på regional nivå har fördelar gentemot att arbeta på en nationell eller global nivå eftersom man har större möjligheter att gå ned på djupet både gällande samhälleliga processer och ekologiska processer. Kopplingen mellan siffror och faktiska skeenden blir tydligare. Parallellt med arbetet med de regionala modellerna har vi också deltagit i lokalt och regionalt arbete för att förståelsen omkring praktiska angreppssätt och mänskligt beteende. Studien av energiflöden i Jämtland visar att 46.000 TJ (varav 88% förnyelsebart) flödar in i regionen och 31.000 TJ exporteras ut och att resterande 15.000 TJ (varav 63% förnyelsebart) driver maskineriet Jämtland. Till detta kommer omkring 4000 TJ i form av material. Den totala GWP20-påverkan från Jämtland är ’kylande’ och motsvarar ett upptag av koldioxid-ekvivalenter årligen på 2.4 Mton, vilket ungefär motsvarar emissionen från225.000 genomsnittssvenskar. De totala antropogena emissionerna av CO 2eq , inklusive konsumtion, är 1500 kton. Regionen uppvisar betydande emissioner av metan, 80 kton (motsvarande 6700 kton CO 2eq ) från sjöar, myrar och våtmarker samt djur. Jämtland kan ur flera perspektiv betraktas som relativt hållbart, men tar man de enorma skogsarealerna och den i ett internationellt perspektiv blygsamma befolkningen på 127 000 personer i beaktande är hållbarheten mindre övertygande. Vidare är 37% av den energi som driver Jämtland faktiskt icke-förnyelsebar. Sett ur ett globalt perspektiv och med hänvisning till Jämtlands enorma naturresurser behöver Jämtland prestera bättre. Hur man skall kunna öka den långsiktiga hållbarheten är en komplex fråga som kräver belysning från flera olika perspektiv. Resultat som de som presenteras här måste tolkas tillsammans med regionala intressenter i ett bredare hållbarhetssammanhang för att kunna utarbeta lämpliga implementeringsstrategier. / <p>Vid tidpunkten för framläggningen av avhandlingen var följande delarbete opublicerat: delarbete 4 (manuskript).</p><p>At the time of the defence the following paper was unpublished: paper 4 (manuscript).</p>

Dans ce travail, un moteur Stirling de type Gamma alimenté par énergie solaire avec une faible différence de température a été étudié numériquement et expérimentalement. Un nouveau modèle appelé Polytropic Stirling Model with Losses (PSML) a été proposé et appliqué au moteur GPU-3 Stirling. Un cryoréfrigérateur basé sur un moteur Stirling intégral de type Alpha a été étudié numériquement, après avoir mesuré ses dimensions géométriques au laboratoire. Pour le moteur Stirling de type gamma du laboratoire, le modèle ait thermodynamique à vitesse finie et le modèle isotherme a été développé, incluant les bilans de masse et d’énergie à travers les différents volumes (compression, régénération et expansion) dans le moteur. Différents types de pertes thermiques et mécaniques ont été considérés dans le modèle afin d'analyser les processus thermodynamiques et les pertes dans le moteur Stirling. En outre, des études paramétriques sur les performances du moteur Stirling alimenté à l’énergie solaire ont également été étudiées expérimentalement et numériquement. La comparaison entre les résultats expérimentaux et les résultats de simulation à différents déphasages entre le déplaceur et le piston, et à différentes course de piston montre que le modèle est convaincant dans la prédiction des performances du moteur Stirling. Basé sur la méthode thermodynamique en dimension physique finie, une méthode d’algorithme génétique multi-objectives, objectifs étant la puissance fournie, le rendement énergétique et le taux de génération d'entropie a été utilisé pour optimiser la fonction et la géométrie du moteur du type Gamma. En comparant avec la méthode d'optimisation écologique, la méthode multi-objectif permet de mieux équilibrer les trois objectifs. Le nouveau modèle (PSML) proposé pour prédire les performances du moteur de type Bêta ou Gamma du moteur Stirling, il divise l'espace de travail en 5 parties (volume de compression, refroidisseur, régénérateur, chauffage et volume d'extension). Une liaison entre volume de compression et volume d'extension a été ajoutée dans le modèle adiabatique classique du moteur Stirling. Ainsi, des processus polytropiques ont été considérés dans les volumes de compression et d'expansion du moteur Stirling. Le moteur Stirling GPU-3 a été utilisé pour valider le nouveau modèle. Il a été démontré que le nouveau modèle (PSML) prédit correctement la puissance de sortie et le rendement du moteur. Dans la dernière partie de la thèse, un Cryorefroidisseur Stirling de type Alpha, a été étudié en utilisant un modèle isotherme prenant en considération différentes pertes. Les volumes de compression et d'expansion sont considérés isothermes, et la variation de la température du régénérateur est considéré linéaire. Les bilans d'énergie et d'exergie du Cryorefroidisseur ont été réalisés, et l'effet de divers paramètres sur la performance (puissance de refroidissement et puissance mécanique consommée) est étudié. Les résultats de la simulation pour PPG-102 Stirling cryocooler ont été comparés avec deux autres résultats de simulation de la littérature et des résultats expérimentaux indiquant que ce modèle est convaincant pour prédire la performance du Cryorefroidisseur. / In this work a solar powered low temperature difference Gamma type Stirling engine has been studied experimentally and numerically using an isothermal model coupled with various losses and using an objective optimization. A new model named Polytropic Stirling Model with Losses (PSML) has been proposed which was applied to the Beta type GPU-3 Stirling engine. An Alpha type integral Stirling cryocooler has been studied numerically using an isothermal model with losses. To study a Gamma type Stirling engine of our laboratory, an isothermal model coupled with finite speed method has been developed, including mass and energy balances through different spaces of the engine. The engine is divided into 3 volumes: compression volume, regeneration volume, and expansion volume. Different kind of thermal and mechanical losses have been considered in the model, in order to analyze thermodynamic processes and losses in the Stirling Engine. In addition, parameter effects on the performance of the solar powered gamma type Stirling engine have also been studied experimentally and numerically. The comparison between the experimental results and the simulation results at different phase shift between the displacer and the piston, and at different piston stroke shows that the model is convincing to predict the Stirling engine performance. Based on the Finite Physical Dimensional Thermodynamic method, a multi-objective genetic method considering output power, thermal efficiency and entropy generating rate as objective functions simultaneously, has been used to multi-objective optimize the Gamma type Stirling engine. Comparing with the ecological optimization method, the multi-objective method can better balance the three objective goals. The new model (PSML) proposed in the thesis for predicting performance of Beta or Gamma type of Stirling engine divides the working space into 5 parts (compression volume, cooler, regenerator, heater, and expansion volume). A bypass linking compression volume and expansion volume has been added in the classic adiabatic model of Stirling engine. Thus, polytropic processes have been considered in the compression and expansion volumes of the Stirling engine. The GPU-3 Stirling engine has been used to validate the new model. It was shown that the new model (PSML) predict well the output power and the thermal efficiency of the engine well. An isothermal model considering various losses was developed and presented in the last part of this thesis to study an Alpha type Stirling cryocooler, whose geometrical dimensions were measured in our laboratory. The compression and expansion volumes are supposed to be isothermal, the variation of the regenerator temperature is supposed to be linear. Energy and exergy balances of the cryocooler were developed. The effect of various parameters on the cryocooler performance (cooling power and input power) are investigated. The simulation results for PPG-102 Stirling cryocooler were compared with two other simulation results of the literature and with experimental results which indicated that this model is convincing to predict the performance of the Stirling cyocooler

Dans le contexte économique et énergétique actuel, la mise en œuvre de technologies à l'aide de l'énergie renouvelable comme source de chauffage offre un double avantage: la réduction de la pollution et des coûts de carburant. Il y a un besoin de promouvoir les sources renouvelables d'énergie comme les sources significatives de production d'énergie pour les systèmes décentralisés. Une première étude bibliographique a été fait sur les technologies existantes pour la production d'énergie électrique à partir du solaire. Cette étude consiste dans la recherche d’une nouvelle solution de conversion de l’énergie solaire pour la production d’électricité de faible puissance. L'un des objectifs de cette thèse a été la construction d'un moteur Stirling de type gamma fonctionnant à basse différence de température, adapté à un circuit solaire (capteur plan). Le moteur Stirling a été testé en vue de comparer les résultats expérimentales avec les résultats d’un model Schmidt, fait dans le logiciel, Matlab. Un autre cycle thermodynamique étais étudie dans cette travail, le Cycle Organique Rankine (ORC). Un modèle mathématique a été développé et vérifie dans les logiciels, Thermoptim et EES (Engineering Equation Solver) avec les résultats expérimentaux pour étudier les performances d'installation avec des différentes températures de fonctionnement. La méthode exergétique et la méthode du Pincement sont utilisée pour évaluer les performances du système comme irréversibilité, destruction d’exergie et phénomènes qui se produisent dans toutes les composantes du système ORC pour améliorer son fonctionnement. / In the current economic and energy context, implementation of technologies using renewable energy as heat source has two advantages: reducing pollution and fuel costs. There is a need to promote renewable energy sources such as significant sources of power generation for decentralized systems. In the first part, it was made a literature review on existing technologies for the production of electricity with solar energy. One of the objectives of this thesis was to build a Stirling engine gamma type suitable to use solar energy (flat plate collator). The Stirling engine was tested to compare the experimental results with the results of Schmidt model, realized in the software, Matlab. Another thermodynamic cycle was studied in this work, the Organic Rankine Cycle (ORC). A mathematical model was developed and verified in software, Thermoptim and EES (Engineering Equation Solver) with experimental results to study the installation performance function of different operating temperatures. The entire system and each subsystem are analyzed according to the first and the second law of thermodynamics. The exergy method and Pinch analysis are used to evaluate the performance of the system like irreversibility and exergy destruction, phenomenon that occurs in all components of the ORC system. This analysis is to improve the operation.

Cette étude concerne un système de stockage d’électricité basé sur le stockage thermique. Le principe est de convertir de l’électricité issue d’énergies renouvelables en chaleur lorsque la production est supérieure à la demande, de conserver cette chaleur puis de la reconvertir en électricité lorsqu’un besoin se présente. Le système proposé s’appuie sur une technologie de stockage sensible à haute température : le stockage régénératif gaz/solide. Ce stockage est associé à une boucle de charge et à un cycle thermodynamique de restitution électrique. Dans cette étude, deux architectures sont étudiées pour ce dernier : la première est basée sur un cycle gaz, la seconde sur un cycle combiné Joule/Rankine. Un modèle global du système est développé sur la base d’une modélisation de chaque composant à un niveau de détail approprié. Sur la base de ce modèle, une analyse thermodynamique est menée. Celle-ci identifie le rendement exergétique global du procédé, proche de celui d’un cycle à combustion. Une analyse exergétique détaillée du stockage identifie les principaux postes d’irréversibilités dans ce composant. Elle montre qu’il est possible d’optimiser de manière relativement simple ses performances en jouant sur son dimensionnement. Par la suite, une analyse économique montre qu’en dépit de ses performances inférieures, le cycle gaz est associé à des coûts d’investissement limités qui rendent son utilisation pertinente. En termes de coût du stockage, le système étudié est compétitif avec des solutions comme les batteries. / This study concerns an electricity storage system based on thermal energy storage. Its overall purpose is to convert electricity produced by renewable energies into heat when the supply exceeds the demand. This heat is stored for a few hours and converted back to electricity when there is a need for it. The proposed system relies on a high temperature sensible thermal energy storage technology known as the gas/solid packed bed thermal storage. This storage comes with a charging loop and a thermodynamic cycle to carry out the heat to electricity conversion. In this study, two main architectures are considered for this cycle: a simple gas cycle and a Joule/Rankine combined cycle. Each component is modeled with an appropriate level of detail in order to create a global model of the system. This model is used to carry out a thermodynamic analysis. This study calculates the global exergy efficiency of the whole process, which is close to exergy efficiency of a combustion cycle. A detailed exergy analysis of the storage allows to identify the main phenomena behind the availability losses of this component. It shows that it is possible to increase the efficiency of the storage by modifying its sizing. Apart from this study, an economic analysis shows that regardless of its low energy and exergy efficiencies, the gas cycle comes with limited investment costs which insure an interesting profitability. In terms of storage cost, the proposed system is close to other electricity storage solutions like batteries.

Made available in DSpace on 2014-06-11T19:35:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04Bitstream added on 2014-06-13T18:47:03Z : No. of bitstreams: 1 reis_ja_dr_guara.pdf: 3822491 bytes, checksum: c9fd5a88d775153288d737de07be90be (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho desenvolve o projeto, aqui entendido como a seleção das unidades que atendam às exigências de obtenção de eletricidade, calor e frio, e a montagem de um sistema de cogeração que usa um motor de pequeno porte associado a uma máquina de absorção e trocadores de calor que satisfarão tais exigências de uma maneira a mais econômica possível, isto é, otimizado em termos de custos. Aplicando-se um método de obtenção dos custos associados à exergia, cria-se um quadro de custos exergéticos para a obtenção de cada produto, e a soma de cada custo constitui o que chama-se de custo de manufatura exergética. O estudo demonstra que é possível aplicar esse método e identificar os pontos de deficiência de um sistema térmico como o mostrado e ,com isso, tomar medidas que venham a melhorar seu desempenho. Essa otimização física não se utiliza de conhecidos algoritmos de otimização matemática, utilizando-se de dados físicos e termodinâmicos medidos, O método permite identificar a forma operacional (basicamente a rotação do motor) que apresente os menores custos. A compreensão dos aspectos gerais da cogeração, das tecnologias envolvidas, com suas vantagens e desvantagens, torna possível aplicar a avaliação exergética associada a conceitos econômicos,e, com essa análise, tomar-se medidas que melhorem o desempenho do sistema em estudo. / This work develop the design of a cogeneration system with a small internal combustion engine coupled with an absorption refrigeration unit utilised in the production of a refrigeration effect, heating effect and electrical power generation with the utilization of exhaust waste heat, in a most possible economic way, i.e., optimized within limits of costs. By developing a method of costs associated to exergy, raises an exergetic costs for each unit, and the total costs is called manufacture exergetic cost. This study demonstrate that the appliance of this method identify the failures in the system and indicate where applies measures that improves its performance. This optimization do not utilizes mathematical algorithms, it is a physical optimization that use thermodynamics and physical data. The objective of this method is to identify the operational form that introduces the smaller cost. This compact cogeneration system have an internal combustion engine coupled with two heat exchangers and an absorption engine. The comprehension of general aspects of cogeneration technologies, its advantages and disadvantages turn possible to apply the exergetic evaluation associated with economic concepts to improve the performance of the system.

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.

Resumo: Este trabalho desenvolve o projeto, aqui entendido como a seleção das unidades que atendam às exigências de obtenção de eletricidade, calor e frio, e a montagem de um sistema de cogeração que usa um motor de pequeno porte associado a uma máquina de absorção e trocadores de calor que satisfarão tais exigências de uma maneira a mais econômica possível, isto é, otimizado em termos de custos. Aplicando-se um método de obtenção dos custos associados à exergia, cria-se um quadro de custos exergéticos para a obtenção de cada produto, e a soma de cada custo constitui o que chama-se de custo de manufatura exergética. O estudo demonstra que é possível aplicar esse método e identificar os pontos de deficiência de um sistema térmico como o mostrado e ,com isso, tomar medidas que venham a melhorar seu desempenho. Essa otimização física não se utiliza de conhecidos algoritmos de otimização matemática, utilizando-se de dados físicos e termodinâmicos medidos, O método permite identificar a forma operacional (basicamente a rotação do motor) que apresente os menores custos. A compreensão dos aspectos gerais da cogeração, das tecnologias envolvidas, com suas vantagens e desvantagens, torna possível aplicar a avaliação exergética associada a conceitos econômicos,e, com essa análise, tomar-se medidas que melhorem o desempenho do sistema em estudo. / Abstract: This work develop the design of a cogeneration system with a small internal combustion engine coupled with an absorption refrigeration unit utilised in the production of a refrigeration effect, heating effect and electrical power generation with the utilization of exhaust waste heat, in a most possible economic way, i.e., optimized within limits of costs. By developing a method of costs associated to exergy, raises an exergetic costs for each unit, and the total costs is called manufacture exergetic cost. This study demonstrate that the appliance of this method identify the failures in the system and indicate where applies measures that improves its performance. This optimization do not utilizes mathematical algorithms, it is a physical optimization that use thermodynamics and physical data. The objective of this method is to identify the operational form that introduces the smaller cost. This compact cogeneration system have an internal combustion engine coupled with two heat exchangers and an absorption engine. The comprehension of general aspects of cogeneration technologies, its advantages and disadvantages turn possible to apply the exergetic evaluation associated with economic concepts to improve the performance of the system. / Orientador: José Luz Silveira / Coorientador: Edson Bazzo / Banca: Pedro Magalhães Sobrinho / Banca: Julio Santana Antunes / Banca: Jose Rui Camargo / Banca: Newton Galvão de Campos Leite / Doutor