Afin de faire face aux fortes températures rencontrées par les composantsen aval de la chambre de combustion, des prélèvements d’air plus frais sont réalisésau niveau du compresseur. Cet air alimente les cavités en pied de turbine et refroidiles disques rotor permettant d’assurer le bon fonctionnement de la turbine.Ce manuscrit présente une étude numérique de l’effet de ces écoulements de cavitéau pied de la turbine sur ses performances aérodynamiques. Les phénomènesd’interaction entre l’air de cavité en pied de turbine et l’air de veine principal est unphénomène encore difficilement compris. L’étude de ces phénomènes est réalisée autravers de différentes approches numériques (RANS, LES et LES-LBM) appliquéesà deux configurations pour lesquelles des résultats expérimentaux s ont disponibles.Une première configuration en grille d’aube linéaire en amont de laquelle différentesgéométries d’entrefer (interface entre plateforme rotor et stator) et débits de cavitépouvaient être variés. Une seconde configuration annulaire composée de deux étagesde turbine comprenant les cavités en pied et plus proche d’une configuration industrielle.Les pertes additionnelles associées à l’écoulement de cavité sont mesurées etétudiées à l’aide d’une méthode basée sur l’exergie (bilans d’énergie dans l’objectifde générer du travail). / In order to deal with high temperatures faced by the components downstreamof the combustion chamber, some relatively cold air is bled at the compressor.This air feeds the cavities under the turbine main annulus and cool down the rotordisks ensuring a proper and safe operation of the turbine. This thesis manuscriptintroduces a numerical study of the effect of the cavity flow close to the turbine hubon its aerodynamic performance. The interaction phenomena between the cav-ity andmain annulus flow are not currently fully understood. The study of these phenomenais performed based on different numerical approaches (RANS, LES and LES-LBM)applied to two configurations for which experimental results are avail-able. A linearcascade configuration with an upstream cavity and various rim seal geometries(interface between rotor and stator platform) and cavity flow rate avail-able. Arotating configuration that is a two stage turbine including cavities close to realisticindustrial configurations. Additional losses incurred by the cavity flow are measuredand studied using a method based on exergy (energy balance in the purpose togenerate work).

Magistro baigiamajame darbe nagrinėjami vėdinimo įrenginiai su integruotais šilumos siurbliais. Darbe atliekama tokios rūšies įrenginių literatūros apžvalga. Apžvelgiami šilumos siurblio komponentai, darantys didžiausią įtaką jo darbui. Darbo metu atlikti įrenginių projektavimo ir konstravimo darbai. Pateikiamos projektavimo rekomendacijos. Lyginami skirtingi kompresorių galios moduliacijos principai. Nagrinėjami įrenginių darbo režimai, kylančios problemos eksploatacijos metu, ieškomi problemų sprendimų būdai. Pateikiamos kintamo sukimosi greičio kompresorių galių moduliacijos ribos. Atliekamos energinė ir ekserginė analizės pagal eksperimentinio bandymo duomenis. Nustatomi realūs termodinaminio efektyvumo ir naudingumo koeficientai. Jautrumo analizės metu atliekami elektrinio šildytuvo efektyvumo ir naudingumo skaičiavimai. Pateikiami rezultatai, išvados ir rekomendacijos tokios rūšies įrenginių tobulinimui ir tolimesniam vystymui. Darbo apimtis – 94 psl. teksto be priedų, 66 iliustr., 7 lent., 43 bibliografiniai šaltiniai. / Master's thesis examines air handling units with integrated air source heat pumps. Literature review about this type of units was carried out. An overview of mostly important heat pump‘s components are given. Thesis was an opportunity to design, construct and analyze these units. Different heat pump‘s operation modes examined and main issues turned out. Based on experimental data variable speed compressor's capacity modulation results defined. Moist air thermodynamic calculations have been made and air handling unit with integrated air source heat pump experimental energy and exergy efficiency was defined. Sensitivity evaluation changing heat pump with electric heater carried out. The main recommendation provided for units designing and further development. Thesis consist of 94 p. text without appendixes, 66 pictures, 7 tables, 43 bibliographical entries.

Este trabalho trata da questão da redução de consumo de combustível fóssil em instalações de máquinas de navios. É um tema de grande interesse no momento, devido ao alto custo operacional e à emissão de poluentes decorrentes do processo da combustão desses derivados de petróleo. Apresenta-se, inicialmente o cenário atual e tendências futuras das instalações propulsoras convencionais que usam óleo pesado ou Diesel. Em seguida, são examinadas alternativas propostas para redução de consumo de combustíveis fósseis nos navios, que são enquadradas em três categorias. A primeira delas envolve possíveis melhorias de projeto para redução da demanda de energia. As outras categorias se referem ao emprego de fontes alternativas de energia, que introduzem uma força propulsora adicional, reduzindo o empuxo requerido do hélice, ou uma potência suplementar no eixo propulsor. Em ambos os casos há também uma redução de demanda de potência requerida do motor Diesel. Na seqüência, são apresentados e discutidos fundamentos termodinâmicos, com ênfase nas análises energética e exergética, como ferramentas para avaliação das máquinas dos navios. A análise exergética, diferentemente do enfoque apenas energético, é a ferramenta mais apropriada para tratar as questões ligadas ao meio ambiente, pois a própria definição de exergia está relacionada com o ambiente de referência. Finalmente, utilizando dados de um navio porta contêineres da frota nacional, é exercitado um exemplo de aplicação com as análises termodinâmicas do motor de propulsão; são também avaliadas e simuladas as diversas alternativas de melhorias e novas fontes de energia, que visam a redução de consumo de combustível fóssil. / This work addresses the issue of reduction of fossil fuel use on ship machinery. Presently it is an interesting topic due to high operational cost and the pollution emissions generated by the combustion process. Initially, it is introduced the present scenario and future trends regarding conventional ship machinery that use heavy or diesel fuel oil. In the sequence, the proposed alternatives for reducing the use of fossil fuel on ships are presented and examined. These alternatives are classified into three categories. The first category comprises possible improvements to the design of ships for reduction of total energy demand. The other categories refer to the use of alternative energy sources, that produce and additional force on the ship reducing the required propeller thrust; or a supplementary power added to the propulsion shaft. For both cases there is also a reduction in the power required from the Diesel engine. Afterwards, the pertaining thermodynamics theory is revised and discussed with focus on the energy and exergy analysis as aid tools for evaluation of ship machinery. The energetic analysis, different from the sole energetic focus, is the most applicable tool to be employed for environmental issues as the self definition of exergy relates to an environment reference. Finally, using data from a typical container ship belonging to the national fleet, an application example using the thermodynamic analysis is performed to the propulsion main engine; as well as it is also simulated several alternative conditions for improvements and new energy sources, aiming to the reduction of fossil fuel consumption.

La pompe à chaleur industrielle très haute température (PAC THT) à compression mécanique de vapeur, fonctionnant à l'électricité, figure parmi l'une des technologies innovantes les plus efficaces permettant de valoriser les rejets thermiques industriels à basse et moyenne température (<90 °C). Néanmoins, compte tenu des besoins industriels actuels de chaleur, les niveaux de température cible atteignable par les PACs restent trop faibles et freinent fortement son implantation. Les procédés de séchage, dans leur grande majorité, rejettent des buées ou de la vapeur d'eau à moyenne température (50 °C-90 °C) et ont des besoins de chaleur à très haute température (110 °C-150 °C). Le grand écart de température entre la source et le besoin de chaleur ainsi que le niveau de température du besoin, font qu'aujourd'hui envisager l'intégration d'une PAC dans ce type de procédés relève d'un défi énergétique et technologique particulièrement intéressant, dont l'enjeu économique est considérable. Les présents travaux de recherche envisagent à l'aide d'une méthodologie générique d'optimisation de cycles thermodynamiques basée sur la minimisation de la production d'entropie dans les échangeurs de chaleur de déceler les architectures de PACs les plus efficaces d'un point de vue énergétique. L'analyse théorique a permis de déceler la haute efficacité énergétique des architectures transcritiques de PACs dans des conditions de grands glissements de température entre l'entrée et la sortie du besoin de chaleur. Le développement d'un démonstrateur de PAC transcritique très haute température fonctionnant au R32 (PAC T-THT R32) a permis d'une part de démontrer la faisabilité technique d'une PAC, pouvant atteindre la température cible de 120 °C en partant de 60 °C avec une source de chaleur disponible à 50 °C, et d'autres part de démontrer sa haute efficacité énergétique (COP = 4). / The mechanical vapour compression high temperature heat pump for industry using electricity is one of the most effective innovative technologies to recover the industrial waste heat at low and medium temperature (<90°C). However, given the current industrial heat needs, the heat pump target temperature levels remain too low and slow strongly its implantation. Overwhelmingly, the drying processes reject saturated moist air at middle temperature (50°C-90°C) and have heat needs at very high temperature (110°C-150°C). The large temperature difference between the source and the heat need and the level off temperature that is needed, today, makes the heat pump integration in such processes an interesting energy and technological challenge, whose economic stake is considerable. The present works tackle, with a generic methodology of thermodynamic optimisation cycles based on the entropy minimization in the heat exchangers, to identify the most efficiency heat pump architectures from an energy point of view. The theoretical analysis allowed to detect the transcritical heat pump architecture, in conditions of high temperature glides between the inlet and the outlet of the heat need. The development of a transcritical high temperature heat pump demonstrator using the R32 as working fluid allowed to demonstrate the technical feasibility of a heat pump that can reach the target temperature of 120°C from 60°C with an available heat source at 50°C, and to demonstrate its high energy efficiency (COP = 4).

Ce travail de thèse concerne l’étude de la faisabilité des cycles organiques sous-critiques et supercritiques de Rankine pour la valorisation de rejets thermiques industriels à basse température. Dans un premier temps, un état de l’art des cycles ORC (acronyme anglais pour Organic Rankine Cycle) et leurs fluides de travail a été réalisé. Nous avons réalisé une comparaison préliminaire de plusieurs configurations à partir de la littérature scientifique. Dans un second temps, les méthodes d’analyse énergétique et exergétique ont été appliquées pour évaluer et optimiser les performances des cycles ORC. En effet, la seule méthode d’analyse énergétique n’est pas suffisante pour juger de la bonne utilisation du potentiel énergétique de la source de chaleur disponible correspondant à un rejet industrielle de chaleur (chaleur fatale). L’analyse exergétique, intervient en complément de l’analyse énergétique du système, afin de permettre de localiser les pertes des ressources énergétiques dans les différentes composantes du système et de déterminer leurs importances relatives et leurs causes. Une optimisation thermo-économique des installations de valorisation de rejets thermiques utilisant un cycle sous-critique ou supercritique de Rankine a été effectuée. Nos résultats montrent que la valorisation de rejets thermiques industriels à basse température (ex. source thermique de 150 °C) en utilisant un cycle ORC sous-critique est plus intéressante sur le plan énergétique que celle opérée en utilisant un cycle supercritique de Rankine. / This thesis concerns the feasibility study of subcritical and supercritical organic Rankine cycles for industrial waste heat recovery at relatively low temperature. Initially, a state of the art of ORCs (Organic Rankine Cycles) and their working fluids has been achieved. We conducted a preliminary comparison of several configurations from the scientific literature. In a second step, methods of energy and exergy analysis were applied to evaluate and optimize the performance of the ORCs. Indeed, sole energy analysis is not enough to access the proper use of the energy potential of the available heat source that corresponds to an industrial waste heat. Exergy analysis, in a complementary way to the energy analysis, enables us to locate the energy resources losses in the various components of the system and to determine their true magnitude and their causes. A thermo-economic optimization of waste heat recovery systems using a subcritical or supercritical Rankine cycle has been performed. According to the results, the industrial waste heat recovery at low temperature (e.g. heat source 150 ° C) using a subcritical ORC is more interesting on economic point of view than the system using a supercritical Rankine cycle

Orientador: Ivonete Ávila / Resumo: O crescimento populacional e o progresso tecnológico têm levado a crescente demanda por recursos naturais e energia, resultando na intensificação de impactos ambientais. O setor de energia é um dos principais emissores de CO2 antropogênico, principalmente devido a utilização de combustíveis fósseis, o que tem levado à busca por soluções tecnológicas visando a redução dos impactos ambientais associados à sua geração. Nesse contexto, esse trabalho visa realizar uma avaliação de desempenho ambiental da geração de energia elétrica das centrais termelétricas Fernando Gasparian e Piratininga com inserção da técnica de captura de CO2 por oxicombustão. Essa avaliação é realizada por meio de uma proposta conceitual própria que inclui avaliação do ciclo de vida (ACV) e avaliação termodinâmica com bases exergéticas. A avaliação termodinâmica abrange a operação das termelétricas, por meio de análise energética e exergética utilizando a teoria do custo exergético e o método CExC (cumulative exergy consumption). A ACV abrange desde a extração dos recursos até o fim de vida das instalações, utilizando os métodos de contabilização de recursos CED (cumulative energy demand), CExD (cumulative exergy demand) e CML IA baseline. Os resultados da avaliação termodinâmica permitiram verificar que a câmara de combustão é a principal destruidora de exergia e a inserção da técnica de oxicombustão impõe maior penalidade energética por causa da inserção dos componentes de separação de ar e processamento ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Population growth and technological progress have led to an increasing demand for natural resources and energy, resulting in the intensification of environmental impacts. The energy sector is one of the main emitters of anthropogenic CO2, mainly due to the use of fossil fuels, which has led to the search for technological solutions aimed at reducing the environmental impacts associated with its generation. In this context, this work aims to carry out an environmental performance evaluation of the electric power generation at the Fernando Gasparian and Piratininga thermoelectric plants with the insertion of the CO2 capture technique by oxy-combustion. This assessment is carried out through a conceptual proposal that includes life cycle assessment (LCA) and thermodynamic assessment with exergetic bases. Thermodynamic evaluation covers the operation of thermoelectric plants, through energy and exergetic analysis using the theory of exergetic cost and the CExC method (cumulative exergy consumption). ACV covers everything from resource extraction to the end of the facility's life, using the resource accounting methods CED (cumulative energy demand), CExD (cumulative exergy demand) and CML IA baseline. The results of the thermodynamic evaluation allowed to verify that the combustion chamber is the main destroyer of exergy and the insertion of the oxy-combustion technique imposes a greater energy penalty due to the insertion of the air separation unit and CO2 processing unit for CO2... (Complete abstract click electronic access below) / Doutor

Within a production machine, various electromechanical and pneumatic structures can be used for drive tasks. As these drive technologies can often replace each other, the energy efficiency, performance and TCO of pneumatic drives must be permanently enhanced to remain competitive. There is a large number of known measures for the reducing their energy consumption, e.g. minimizing of filling volumes, energy saving circuits etc. However, these measures are mainly considered separately and the possible overall energy saving effect resulting from their combination is rarely taken into account. The main goal of this paper is therefore to explore the possible combinations of pneumatic energy saving measures and their cumulative saving effect. Due to the fact that some measures are mutually exclusive (e.g. a general pressure reduction in properly sized drive), each combination should be considered separately. To evaluate their efficiency plausibly, a comprehensive assessment is required that contains both the total cost of ownership analysis (TCO) and a mechanical properties assessment. The presented comprehensive approach of the task analysis can serve as example of how an optimal drive configuration for the specific task can be found, thus creating a basis for solving constructive challenges in designing of pneumatic automation systems.

Då varje människa tillbringar större del av dagen inomhus så är det viktigt att ha en bra termisk komfort, efter som den termiska komforten påverkar upplevelsen på jobbet i hemmet eller i skolan. Människor kan påverkas negativt när den termiska komforten inte uppfyller kraven.   Syftet med undersökningen är att undersöka hur lågtemperaturssystemens förmåga är med avseende på termisk komfort och om de uppfyller kraven. Undersökningen använder beräknings data från tidigare utfört arbete då beräkningarna valideras av jämförelse mot andra undersökningar.   I detta arbete undersöker vi skillnader mellan golvvärme och luftvärme, där vi ser hur de olika systemen jämförs mot varandra under kontrollerade förhållanden med avseende på termisk komfort. De olika systemen som undersöks är luftvärme som är placerad under tak, luftvärme placerad under ett fönster, golvvärme som är jämnfördelad över golvet och golvvärme jämnfördelad med extra slingor under fönster. I undersökningen utförs en litteraturstudie som kommer att ligga till grund för vad ämnet för lågtemperatur innefattar samt hur de olika systemen fungerar och hur dessa kan användas som lågtemperaturssystem. Då i denna undersökningen så beaktas operativa temperaturen PMV, PPD och dragindex för att få en bra uppfattning hur den termiska komforten upplevs med avseende på golvvärme och luftvärme. Undersökningen har gett goda resultat då skillnaden i termisk komfort mellan de olika systemen har varit minimala och uppfyllt alla krav enligt BBR. Resultaten har jämförts mot tidigare gjorda undersökningar av lågtemperaturteknik och resultaten sammanfaller bra med små avvikelser. För att välja ett av de fyra systemen som har visats bättre resultat med hänsyn på termisk komfort så har golvvärme med extra slingor under fönster bevisats vara det bättre alternativet, då PMV och PPD samt drag ligger under rekommendationen för termisk komfort. / When most people spend a larger part of the day indoors, it is important to have a good thermal comfort, as the thermal comfort affects the experience that you perceive when you are at work, at home or at school. This may then affect the health if the thermal comfort does not meet the requirements. The purpose of the survey is to investigate low temperature system performance in terms of thermal comfort and if it meets the requirements. The survey uses calculation data from previously performed surveys, as the calculations are validated by comparison with other surveys. In this survey we explore the differences between floor heating and air heating, where we look at how the different systems are compared to each other under controlled conditions regarding thermal comfort. The different systems under investigation are air heating placed on the wall, air heating placed under a window, floor heating evenly distributed over the floor and floor heating that has extra loops under windows. The study will carry out a literature study that will be based on the topic of low temperature and how the different systems work and how they can be used at low temperatures. In this survey, the operating temperature PMV, PPD and DR-index are considered to get a good idea of how thermal comfort is experienced regarding floor heating or air heating. The survey has given good results, since the difference in thermal comfort between the different systems has been minimal and fulfilled all BBR requirements. The results have been compared to previous studies of low temperature technology, as the results coincide well with minor deviations. To choose one of the four systems that have been shown superior in terms of thermal comfort, floor heating with extra loops under windows has been proven to be the better option, as PMV and PPD as well as values are below the recommendation for thermal comfort.

This thesis presents a general description of approaches to energy efficient building development under Chinese contexts. The purpose of the work is to discuss how Chinese building development can be approved from an energy saving perspective. Building development is a complicated process that relates to many stakeholders’ interests. The developed countries have studied in this field extensively for several decades. Generally, the approaches to energy saving can be set at three levels: administration, construction industry and architectural design. More new strict codes for energy efficient buildings are being issued for enforcement. At the same time, many research institutes have developed Building Environmental Assessment (BEA) methods, where energy efficiency is an important factor in the models. Various technical solutions for energy efficiency are developed as well. The administrative approaches are not the main objective discussed in the thesis, though the importance of them is undeniable. BEA systems are not only assessment methods, but also market-based stimulating approaches for sustainability of construction market. Technical methods have been developed for a long period. Passive House and Low Exergy (LowEx) Systems are two representative examples in European countries. All of these approaches are relatively unfamiliar to Chinese architects and developers, let alone their effect and applicability. The thesis tries to analyse this situation and their applicability within Chinese context. In China to a certain project, the importance of technical issues is relatively recognized. However, a few successful individual cases in technique can not change the reality that most of new building development has failed in energy efficiency in China. This is a serious situation when China is in an enormous expansion phase in building new houses. The thesis tries to discuss the reasons for this phenomenon. One reason could be that the stakeholders in the developing process are not aware of the importance of collaboration which is the only method to get “Both Win” according to Game theory. The thesis discusses a paradigm to replace two traditional linear paradigms in building developing process. Architects should act as coordinators of different stakeholders rather than technical supporters. The thesis tries to discuss the propositional route of developing energy efficient buildings. Technical approaches are basic research, which presents the concepts that have been proved realizable; BEA encourages developers to develop more energy efficient buildings for economic benefit, which will make good demonstrations for whole market; national laws and policies are final approaches, which ensure that every project will have good performance of energy efficiency. When the old standardization and legislation are finished, a new cycle will begin with more advanced techniques. China government has started the progress to enhance energy efficiency. However, this process will be tough and slow. The thesis discusses Chinese special conditions and the problems that cry out for solution in the future. / QC 20101105

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