En ce début de millénaire 1,4 Milliards d'humains, parmi les plus démunis de la planète, vivent dans des sites isolés et ne bénéficient pas de réseaux de distribution d'énergie. Leur besoin en électricité est modeste, mais important en terme d'usages : accès aux soins médicaux et à l'instruction, communication, développement d'économies locales. C'est face à ce constat que Schneider Electric Industries relève, depuis 2009, le défi de concevoir et réaliser des microcentrales solaires thermodynamiques, concurrentielles à d'autres solutions, pour fournir à ces populations une énergie électrique fiable et respectueuse de l'environnement. Inscrit dans le cadre de ce projet, le présent travail - réalisé en Cifre - est séquencé par l'évolution industrielle du projet. Dans un premier temps, un Etat de l'Art, étendu à une analyse de détail, a contribué à privilégier certains choix technologiques : capteurs solaires à concentration, stockage thermique à chaleur sensible et moteur de Stirling. Dans un second temps, une étude thermodynamique préliminaire a permis d'évaluer le dimensionnement d'éléments clefs du système : champ de captage solaire et stockage thermique. En complément une étude de sensibilité paramétrique du dimensionnement et des performances à divers facteurs de pertes énergétiques a souligné les points durs techniques et participé à l'orientation des travaux de conception. Enfin, l'analyse exergétique de fonctionnement de capteurs solaires et d'un moteur Stirling en régimes dynamiques stationnaires proposent des bases pour l'optimisation de contrôle et commande, visant à accroître les performances énéergétiques du système et favoriser sa viabilité thermoéconomique / As a new millenium begins, 1.4 Billion people worldwide earn less than 2 dollars daily and have no access to the power grid. The need of electric power of these people represent small energy amounts but is very important regarding to the usage : acces to healthcare and education, communication, local economic development. In reponse to the situation, since 2009, Schneider Electric Industries takes up the challenge to design and realize micro solar power plants, competitive with other solutions, to supply these people with reliable and environment-friendly electricity. Dealing with this project, this work has been realized under contract, so it follows the development sequence of the industrial project. The first part is a State of the Art of the actual solar thermodynamical technologies. This task is extended to a qualitative evaluation of various technologies, as a contribution to select adapted technologies: concentrating solar thermal receivers, sensible heat thermal storage and Stirling engine. The secon step is a preliminary thermodynamics analysis of the whole system, that allowed to evaluate key features: the size of the solar receivers area, the thermal storage volume, and overall energy performance. This task is streched by a sensitivity analysis of the sizing and performances, according to various energy losses parameters, that shows the technical hard spots of the design. Finally, an exergy-based dynamical analysis of stationary operating solar receivers and Stirling engines leads to a propostion of basis methods and criteria for the optimal control of power, in order to maximize the energy performances of the system and to enhance its competitiveness

This Master thesis, in collaboration with Morgonsol Väst AB, was completed as a part of the Solar Energy engineering program at Dalarna University. It analyses the electrical and thermal performance of a prototype PVT collector developed by Morgonsol Väst AB. By following the standards EN 12975 and EN ISO 9806 as guides, the thermal tests of the collector were completed at the facility in Borlänge. The electrical performance of the PVT collector was evaluated by comparing it to a reference PV panel fitted next to it. The result from the tests shows an improved electrical performance of the PVT collector caused by the cooling and a thermal performance described by the linear efficiency curve ηth=0.53-21.6(Tm-Ta/G). The experimental work in this thesis is an initial study of the prototype PVT collector that will supply Morgonsol Väst with important data for future development and research of the product.

A tendência em ampliar o uso das tecnologias com aproveitamento da energia solar no setor residencial traz para os profissionais da área de projeto novos desafios que é o de reestruturar seus modelos de concepção e desenvolvimento de projetos a fim de garantir o comportamento em uso e a eficiência dos sistemas construtivos seguros. O Modelo conceitual de identificação e qualificação de risco proposto foi elaborado a partir da pesquisa de investigação e de desenvolvimento experimental. Foram considerados aspectos relativos às demandas de segurança em uso, construção do conhecimento a partir da sistemografia e a forma de integração desses saberes em um único sistema. O desenvolvimento experimental ocorreu durante o processo de projeto, produção, montagem, uso e operação de um protótipo denominado Ekó House. A metodologia aplicada envolveu quatro fases: Fase 1 - Exploratória - com pesquisas bibliográficas (as tecnologias, normas e práticas de projeto; Fase 2 - Definições - com a escolha da base teórica de apoio ao modelo; Fase 3 - Desenvolvimento - proposições e experimentos e Fase 4 - Teste e consolidação. Para validar o modelo aplicou-se a validação por generalização analítica, ou seja, expandir e generalizar a teoria. O modelo proposto, inovador no âmbito da sistemografia, apoiou-se na Teoria do Sistema Geral: teoria da modelização proposta por LE MOIGNE. Essa teoria trabalha com sistemas complexos e se apoia em processadores, são eles: de operação, informação e decisão que condicionam a integração sistêmica do projeto. Verificou-se durante a aplicação do modelo que ele estimula o aprofundamento das análises das soluções de projeto, quando: a)Identifica e formaliza conceitos que suportam o desenvolvimento das soluções nos diversos sistemas; xv b)Facilita a compreensão e síntese das múltiplas informações que precisam ser compatibilizadas no projeto; c)Formaliza um único principio \"segurança do usuário\" para a lógica de concepção e desenvolvimento de projeto; d)Organiza e permite que se priorizem as informações técnicas [fabricantes e normas];e)Facilita o entendimento por meio de informações as ações de organização e coordenação dos sistemas no espaço e de sua relação com as funcionalidades, uso e estética; e f)Fomenta a busca de soluções mais adequadas a segurança do usuário. Sendo assim, o teste do modelo validou a hipótese. Ele contribui como ferramenta guia de aprimoramento do processo de projeto. / The increasing use of solar energy technologies in the residential sector brings new challenges to professionals who work in the field of design, such as the need to restructure their mindset regarding to the conception and to the development of design, in order to ensure the performance and the efficiency of safe building systems. In this context, this thesis main goal is to propose a conceptual model for the identification and qualification of risk within residential architecture that uses solar energy technologies based on systemography. It\'s an investigative and experimental research, considering aspects related to: meet the demands of safety in use, the knowledge construction and how those could be managed. The experimental development was carried out during the process of design, production, assembly, use and operation of a prototype named Ekó House. The applied method has encompassed four stages: 1) Exploratory - bibliographic research about technologies, codes, rules and design practices; 2) Definitions - the choice of the theoretical basis to ground the model; 3) Development - propositions and experiments and 4) Proofing and consolidation. In order to verify the model it was carried out a test wherewith is possible to perform a validation by analytical generalization, that is, expand and generalize the theory. The proposed model, which represents an innovation in sistemography field, was based on LE MOIGNES\'s Systemic Theory. This Theory enabled the implementation in complex systems, using information, decision and operating processors which condition the design systemic integration. The results obtained by the research show that the model: a) incorporates knowledge, thus, being helpful along the decision-making process; b) eases the understanding and the overview of the diverse information needed by the design; c) formalizes a logic of design conception and development; d) xvii organizes and prioritizes the design technical recommendations [rules and manufacturers]; e) is able to promote an interference in the system\'s organization and coordination in space and also in its relation to functionality and aesthetics; it also f) guides the use of more suitable configurations to the design development. The model presents itself as a tool that is capable of reducing misuse of standards, conflicts between building systems, Technologies and architecture, as well as design failures that compromise safety in use.

A presente Dissertação é um estudo a respeito da problemática da utilização dos Sistemas de Aquecimento Solar Térmico para Aquecimento de Água com Coletores Planos em Circuito Direto, no crítico contexto da construção civil paulista para o ponto de vista da Arquitetura e do Urbanismo. Apesar do potencial solar do país e do padrão construtivo dos condomínios horizontais fechados da Região Metropolitana de São Paulo (RMSP), ainda não há regulamentação do uso do aquecimento solar térmico em alguns de seus municípios-sede. Atualmente tem havido a adesão espontânea ao sistema por parte de moradores das residências desses condomínios, decorrente da busca da redução dos gastos e da crescente conscientização ambiental e divulgação da tecnologia. Porém, ainda há necessidade de uma relação mais sistêmica dos coletores solares com a totalidade dos requisitos da edificação e do meio urbano, mesmo em se tratando da legislação específica. Buscando uma constribuição, aqui se propõe um modelo de estudo dos coletores baseado em escalas construtivas que, juntamente com a compreensão multidimensional do assunto, desafiam a atual dicotomia entre as ferramentas de qualidade e a sustentabilidade do ambiente construído. / The present work studies the problematic of using Solar Hot Water Systems by Direct Circuit, among the critics characteristics of civil construction in the State of São Paulo, Brazil. The point of view is of Architecture and Urban Planning. In spite of the high Brazilian levels of solar irradiation and the constructive pattern of horizontal closed condominiums of the metropolitan region of São Paulo (Brazil), which possess a large concentration of high incoming households, use of solar water heating is still not regulated in some of its comprising municipalities. Nowadays, the search for savings, diffusion of related technologies and raising environmental awareness have led to voluntary uptaking of such systems. Yet, regulation of solar collectors still lacks relating to certification of sustainable building practices, which does not relate to architectonic factors, in particular to main urbanistic features present in each given installation site. This work proposes an architectonic scale based model of studying it in order to pursuit the end of dichotomy between quality and sustainability.

Submitted by Fabricia Fialho Reginato (fabriciar) on 2015-06-30T23:58:11Z No. of bitstreams: 1 ClauberFerasso.pdf: 8384052 bytes, checksum: dc9cfb947f94d52412c3434032ae62da (MD5) / Made available in DSpace on 2015-06-30T23:58:11Z (GMT). No. of bitstreams: 1 ClauberFerasso.pdf: 8384052 bytes, checksum: dc9cfb947f94d52412c3434032ae62da (MD5) Previous issue date: 2013-08 / FINEP - Financiadora de Estudos e Projetos / A contribuição das fontes de energias alternativas, principalmente a solar térmica, para a diversificação da matriz energética brasileira é importante devido, principalmente, ao aumento da demanda do consumo de energia elétrica, ocasionado pelo progresso e desenvolvimento da população e do País. Parte deste aumento é consequência do uso simultâneo de milhares de chuveiros elétricos, na maioria das vezes no horário de ponta, considerado um dos responsáveis pelo elevado pico na curva de demanda entre 18 e 21 horas. Frente a isso, a utilização da energia solar através de sistemas de aquecimento solar para o uso doméstico, vem ao encontro deste propósito. Após análise do consumo médio mensal de energia elétrica fornecida pela concessionária AES Sul no período de um ano em um conjunto residencial na cidade de Canoas – RS, foi possível estimar o custo da utilização do chuveiro elétrico nesse local, por domicílio, que representa entre 25 a 30 % da fatura de energia elétrica. A produção de energia térmica através de sistemas de aquecimento solar para pré- aquecimento de água quente para uso doméstico foi simulada utilizando-se o software TRNSYS, para diversas configurações de sistemas (área de coletor e capacidade de armazenamento). A relação entre a demanda de energia para aquecimento de água e a energia produzida pelo SAS foi parametrizada utilizando-se o conceito de fração solar mensal e anual. Foi considerada uma temperatura mínima de consumo de água quente de 40 °C e um perfil de consumo correspondente à taxa de ocupação média dos domicílios no local. Os dados climáticos necessários para a simulação foram obtidos a partir do ano meteorológico típico (TMY) para Porto Alegre. Os resultados obtidos das diversas simulações mostraram que é possível obter uma economia direta para consumidor de até 58% de energia consumida pelo chuveiro elétrico e uma economia de energia estimada em 12.399 kWh para o sistema elétrico ao longo de 20 anos. Estes resultados podem ser melhorados com a diminuição do custo unitário do SAS ou através de incentivos decorrentes da diminuição dos custos de ampliação da capacidade da rede elétrica por parte das concessionárias, decorrentes da mudança do perfil de carga do sistema. / The contribution of alternative energy sources, particularly solar thermal, to diversify the Brazilian energy matrix is important, mainly due to increased demand of electricity consumption, caused by the progress and development of the population as well as the country. Part of this increase is a consequence of the simultaneous use of thousands of electric showers, mostly during peak hours, considered one of the chief responsible for the high peak in the demand curve between 6.00 and 9.00PM. Given this, the use of solar energy, through solar heating systems for domestic use, meets this purpose. After the analysis of the average monthly consumption of electricity provided by the supplier AES Sul in the period of one year in a residential complex in the city of Canoas – RS, it was possible to estimate the cost of using electric showers in that location, per household, which was between 25 to 30% of the electricity bill. The production of thermal energy through solar heating systems for preheating domestic hot water was simulated using the TRNSYS software for various system configurations (collector area and storage capacity). The relationship between energy demand for water heating and energy produced by SAS was parameterized using the concept of monthly and annual solar fraction, considering a minimum temperature of hot water of 40 ° C, and a profile of consumption corresponding to the average occupancy rate of households at the site. The climatic data required for the simulation were obtained from the typical meteorological year (TMY) to Porto Alegre and the results of several simulations showed that it is possible to get direct savings to the consumer up to 58% of energy consumed by electric shower and energy savings estimated at 12,399 kWh for the electricity system over a period of 20 years. These results can be improved by reducing the unit cost of SAS or through incentives from lowering the cost of expanding the capacity of the electric grid by suppliers, resulting from the change of the system load profile.

A tendência em ampliar o uso das tecnologias com aproveitamento da energia solar no setor residencial traz para os profissionais da área de projeto novos desafios que é o de reestruturar seus modelos de concepção e desenvolvimento de projetos a fim de garantir o comportamento em uso e a eficiência dos sistemas construtivos seguros. O Modelo conceitual de identificação e qualificação de risco proposto foi elaborado a partir da pesquisa de investigação e de desenvolvimento experimental. Foram considerados aspectos relativos às demandas de segurança em uso, construção do conhecimento a partir da sistemografia e a forma de integração desses saberes em um único sistema. O desenvolvimento experimental ocorreu durante o processo de projeto, produção, montagem, uso e operação de um protótipo denominado Ekó House. A metodologia aplicada envolveu quatro fases: Fase 1 - Exploratória - com pesquisas bibliográficas (as tecnologias, normas e práticas de projeto; Fase 2 - Definições - com a escolha da base teórica de apoio ao modelo; Fase 3 - Desenvolvimento - proposições e experimentos e Fase 4 - Teste e consolidação. Para validar o modelo aplicou-se a validação por generalização analítica, ou seja, expandir e generalizar a teoria. O modelo proposto, inovador no âmbito da sistemografia, apoiou-se na Teoria do Sistema Geral: teoria da modelização proposta por LE MOIGNE. Essa teoria trabalha com sistemas complexos e se apoia em processadores, são eles: de operação, informação e decisão que condicionam a integração sistêmica do projeto. Verificou-se durante a aplicação do modelo que ele estimula o aprofundamento das análises das soluções de projeto, quando: a)Identifica e formaliza conceitos que suportam o desenvolvimento das soluções nos diversos sistemas; xv b)Facilita a compreensão e síntese das múltiplas informações que precisam ser compatibilizadas no projeto; c)Formaliza um único principio \"segurança do usuário\" para a lógica de concepção e desenvolvimento de projeto; d)Organiza e permite que se priorizem as informações técnicas [fabricantes e normas];e)Facilita o entendimento por meio de informações as ações de organização e coordenação dos sistemas no espaço e de sua relação com as funcionalidades, uso e estética; e f)Fomenta a busca de soluções mais adequadas a segurança do usuário. Sendo assim, o teste do modelo validou a hipótese. Ele contribui como ferramenta guia de aprimoramento do processo de projeto. / The increasing use of solar energy technologies in the residential sector brings new challenges to professionals who work in the field of design, such as the need to restructure their mindset regarding to the conception and to the development of design, in order to ensure the performance and the efficiency of safe building systems. In this context, this thesis main goal is to propose a conceptual model for the identification and qualification of risk within residential architecture that uses solar energy technologies based on systemography. It\'s an investigative and experimental research, considering aspects related to: meet the demands of safety in use, the knowledge construction and how those could be managed. The experimental development was carried out during the process of design, production, assembly, use and operation of a prototype named Ekó House. The applied method has encompassed four stages: 1) Exploratory - bibliographic research about technologies, codes, rules and design practices; 2) Definitions - the choice of the theoretical basis to ground the model; 3) Development - propositions and experiments and 4) Proofing and consolidation. In order to verify the model it was carried out a test wherewith is possible to perform a validation by analytical generalization, that is, expand and generalize the theory. The proposed model, which represents an innovation in sistemography field, was based on LE MOIGNES\'s Systemic Theory. This Theory enabled the implementation in complex systems, using information, decision and operating processors which condition the design systemic integration. The results obtained by the research show that the model: a) incorporates knowledge, thus, being helpful along the decision-making process; b) eases the understanding and the overview of the diverse information needed by the design; c) formalizes a logic of design conception and development; d) xvii organizes and prioritizes the design technical recommendations [rules and manufacturers]; e) is able to promote an interference in the system\'s organization and coordination in space and also in its relation to functionality and aesthetics; it also f) guides the use of more suitable configurations to the design development. The model presents itself as a tool that is capable of reducing misuse of standards, conflicts between building systems, Technologies and architecture, as well as design failures that compromise safety in use.

The percentage of renewable energy within the global electric power generation portfolio is expected to increase rapidly over the next few decades due to increasing concerns about climate change, fossil fuel costs, and energy security. Solar thermal energy, also known as concentrating solar power (CSP), is emerging as an important solution to new demands for clean, renewable electricity generation. Dish-Stirling (DS) technology, a form of CSP, is a relatively new player in the renewable energy market, although research in the technology has been ongoing now for nearly thirty years. The first large plant utilizing DS technology, rated at 1.5 MW, came online in January 2010 in Peoria, AZ, and plants rated for several hundred MW are in the planning stages. Increasing capacity of this technology within the utility grid requires extensive dynamic simulation studies to ensure that the power system maintains its safety and reliability in spite of the technological challenges that DS technology presents, particularly related to the intermittency of the energy source and its use of a non-conventional asynchronous generator. The research presented in this thesis attempts to fill in the gaps between the well established research on Stirling engines in the world of thermodynamics and the use of DS systems in electric power system applications, a topic which has received scant attention in publications since the emergence of this technology. DS technology uses a paraboloidal shaped dish of mirrors to concentrate sunlight to a single point. The high temperatures achieved at the focal point of the mirrors is used as a heat source for the Stirling engine, which is a closed-cycle, external heat engine. Invented by the Scottish clergyman Robert Stirling in 1816, the Stirling engine is capable of high efficiency and releases no emissions, making it highly compatible with concentrated solar energy. The Stirling engine turns a squirrel-cage induction generator, where electricity is delivered through underground cables from thousands of independent, autonomous 10-25 kW rated DS units in a large solar farm. A dynamic model of the DS system is presented in this thesis, including models of the Stirling engine working gas and mechanical dynamics. Custom FORTRAN code is written to model the Stirling engine dynamics within PSCAD/EMTDC. The Stirling engine and various other components of the DS system are incorporated into an electrical network, including first a single-machine, infinite bus network, and then a larger 12-bus network including conventional generators, loads, and transmission lines. An analysis of the DS control systems is presented, and simulation results are provided to demonstrate the system's steady state and dynamic behavior within these electric power networks. Potential grid interconnection requirements are discussed, including issues with power factor correction and low voltage ride-through, and simulation results are provided to illustrate the dish-Stirling system's capability for meeting such requirements.

Η ηλιακή ενέργεια αποτελεί μια από τις κύριες Ανανεώσιμες Πηγές Ενέργειας (ΑΠΕ). Μπορεί να αξιοποιηθεί είτε μετατρεπόμενη σε ηλεκτρισμό είτε σε θερμότητα. Για τη μετατροπή της σε ηλεκτρισμό η κύρια τεχνολογία που χρησιμοποιείται είναι η τεχνολογία των φωτοβολταϊκών. Αντίστοιχα, για την μετατροπή της σε θερμότητα χρησιμοποιούνται ευρέως οι τεχνολογίες των επίπεδων θερμικών ηλιακών συλλεκτών και των θερμικών συλλεκτών σωλήνων κενού. Βασικό ζητούμενο και στις δύο περιπτώσεις αποτελεί η μεγιστοποίηση της αποδοτικότητας τους. Μια από τις μεθόδους που μπορεί να χρησιμοποιηθεί για την αύξηση της αποδοτικότητας μιας ηλιακής συσκευής είναι η χρήση ενισχυτικών ανακλαστήρων. Επίσης, στις συνήθεις τεχνολογίες φωτοβολταϊκών που εφαρμόζονται σήμερα, η μείωση της θερμοκρασίας λειτουργίας τους βελτιώνει την απόδοση τους. Η διπλωματική ερευνητική εργασία που ακολουθεί περιλαμβάνει τη συγκριτική μελέτη φωτοβολταϊκών διατάξεων, επίπεδων θερμικών συλλεκτών και συλλεκτών σωλήνων κενού. Μελετήθηκαν συστήματα φωτοβολταϊκών με τη χρήση διαφόρων μεθόδων ψύξης, ενεργητικών και παθητικών. Επίσης μελετήθηκε η αύξηση της αποδιδόμενης ηλεκτρικής ενέργειας των φωτοβολταϊκών με χρήση ενισχυτικών ανακλαστήρων (ημικατοπτρικός ανακλαστήρας, ανακλαστήρας αλουμινίου (ματ), λευκός ανακλαστήρας). Υλοποιήθηκαν συνδυαστικά συστήματα με ταυτόχρονη ψύξη και χρήση ενισχυτικού ανακλαστήρα και μελετήθηκε η συμπεριφορά τους. Ακόμα, μελετήθηκε η αύξηση της αποδιδόμενης θερμικής ενέργειας επίπεδου ηλιακού θερμικού συλλέκτη με προσθήκη ενισχυτικών ανακλαστήρων (καθρέπτης, ανακλαστήρας αλουμινίου και λευκός ανακλαστήρας). Τέλος, κατασκευάστηκε διάταξη θερμικού συλλέκτη σωλήνα κενού με επίπεδη ανακλαστική επιφάνεια. Πραγματοποιήθηκαν πειράματα με την προσθήκη ενισχυτικών ανακλαστήρων (ημικατοπτρικός ανακλαστήρας, ανακλαστήρας αλουμινίου και λευκός ανακλαστήρας) και μελετήθηκε η αύξηση της θερμικής απόδοσης του συλλέκτη. Με βάση τα αποτελέσματα των πειραμάτων, εξάγονται αντίστοιχα συμπεράσματα και παρατίθενται προτάσεις σχετικά με τις διατάξεις αυτές. / Solar energy is one of the main Renewable Energy Sources (RES). It can be utilized by being transformed into electricity or heat. The main technology used to transform solar energy into electricity is photovoltaics. Respectively, flat plate solar thermal collectors and evacuated tube solar thermal collectors are the technologies mostly used to transform solar energy into usable heat. One of the main concerns on both cases, is the maximization of their performance. The use of booster reflectors is one of the methods that can be implemented in order to increase the performance of a solar device. Also, a method to increase the performance of the main photovoltaic technologies used at the moment, is to cool them. The following diploma – research thesis includes the comparative study of photovoltaic systems, flat plate solar thermal collectors and evacuated tube solar thermal collectors. Photovoltaic systems with the use of various cooling methods, active and passive, were studied. The increase of the photovoltaic electrical output using booster reflectors (semi specular, aluminum reflector and white reflector) was also studied. Combined systems were implemented, with simultaneous cooling and usage of booster reflector, and their behavior was observed. In addition, the increase of the thermal output of a flat plate collector by using booster reflectors (mirror, aluminum reflector and white reflector) was studied. Finally, an evacuated tube solar thermal collector system with an embedded reflective surface was implemented. Experiments were carried out with the addition of booster reflectors (semi specular, aluminum reflector and white reflector) and the increase of the collector’s thermal output was measured. Based on the experimental results, conclusions and suggestions are made about these systems.

Σκοπός της παρούσης διπλωματικής εργασίας είναι η διερεύνηση, μέσω παραμετρικών αναλύσεων, της συμπεριφοράς και απόδοσης ενός δεδομένου Θερμικού Ηλιακού Συστήματος (Θ.Η.Σ.) για την περιοχή της Πάτρας. Στα πλαίσια αυτά, στο πρώτο μέρος της εργασίας περιλαμβάνεται μία βιβλιογραφική έρευνα, η οποία καλύπτει εκτενώς θέματα όπως η ηλιακή ακτινοβολία, κατηγορίες – εφαρμογές και ανάλυση των κύριων συνιστωσών ολοκληρωμένων Θ.Η.Σ., καθώς επίσης και μεθόδους εξομοίωσης τους. Στο δεύτερο μέρος αναπτύσσεται πρόγραμμα υπολογιστή, το οποίο αφ’ ενός υπολογίζει την ηλιακή ακτινοβολία που προσπίπτει σε μία επιφάνεια στην περιοχή της Πάτρας, αφ’ ετέρου προσδιορίζει, μέσω δύο μεθόδων (αναλυτική και f-chart), τα μηνιαία και ετήσια ποσοστά κάλυψης του φορτίου ενός δεδομένου Θ.Η.Σ.. Τα αποτελέσματα των αναλύσεων αυτών εμφανίζονται στη συνέχεια σε σχετικά γραφήματα παρέχοντας διάφορα χρήσιμα συμπεράσματα. / This project includes bibliographic research related to solar thermal systems and a study of performance, via parametrical analysis, for a solar water heating system installed in a hotel unit located in the region of Patras.

Distributed power generation through renewable sources of energy has the potential of meeting the challenge of providing electricity access to the off-grid population, estimated to be around 1.2 billion residing across the globe with 300 million in India, in a sustainable way. Technological solutions developed around these energy challenges often involve thermal systems that convert heat available from sources like solar, biomass, geothermal or unused industrial processes into electricity. Conventional steam based thermodynamic cycle at distributed scale (< 1 MWe) suffers from low efficiency driving scientific research to develop new, scalable, efficient and economically viable power cycles. This PhD work conducts one such study which provides a database of thermal power blocks optimized for the lowest initial investment cost to developers of distributed power plants. The work is divided in two steps; a) feasibility study of various thermodynamic cycles for distributed power generation covering different operating temperature regimes and b) perform their detailed thermo-economic modelling for the heat sources mentioned above. Thermodynamic cycles are classified into three temperature domains namely, low (< 450 K), medium (< 600 K) and high (< 1000 K) T cycles. Any fluid whose triple point temperature is below the typical ambient temperatures is a potential working fluid in the power cycle. Most of the organic and the inorganic fluids satisfy this criterion and can be perceived as potential power cycle fluids. The general notion is that organic fluids are more suited for low or medium temperature cycles whereas inorganic fluids for high temperature ones. Organic fluids can further be classified into hydrofluorocarbon and hydrocarbon. While the former has high global warming potential (GWP), the latter is flammable in nature. Their mixture in certain compositions is found to obviate both the demerits and perform equally well on thermodynamic scales for low T cycles. On the similar lines, mixture of HCs and inorganic fluids, such as propane+CO2 and isopentane+CO2 are found to be more appropriate for medium T applications if the issues like pinch temperature in the regenerator arising due to temperature glide are taken care of. In the high temperature domain, high efficiency Brayton cycle (supercritical CO2) and transcritical condensing cycles are studied with the latter being 2 % more efficient than the former. However, application of the condensing cycle is limited to low temperature ambient locations owing to low critical temperature of CO2 (304 K). In the same cycle configuration, mixture of CO2 and propane (52 and 48%) with a critical temperature of ~ 320 K is observed to retain the thermodynamic performance with the increased heat rejection temperature matched to the tropical ambient conditions. However, these cycles are plagued by the high operating pressures (~300 bar) calling for high temperature steel making the power block uneconomical. In this regard, the advanced CO2 cycles are developed wherein the optimum operating pressures are limited to 150 bar with an increased cycle efficiency of 6 % over the S-CO2 cycle. Feasibility study carried out on these cycles in the Indian context indicates the low and medium T cycles to be better suited for distributed power generation over the high T cycles. In the second part of work, a comprehensive study is performed to optimize the low and the medium T cycles on a thermo-economic basis for the minimum specific investment cost ($/We). Such a study involves development of component level models which are then integrated to form the system of interest, thus, following a bottom-up approach. A major emphasis is given on the development of scroll expander and low cost pebble bed thermal energy storage system that are the reported in the literature as the areas with high uncertainties while connecting them to the system. Subsequently, the key design parameters influencing the specific cost of power from an air-cooled ORC are identified and used to formulate a 7-dimensional space to search for the minimum costs for applications with a) geothermal/waste or biogas heat sources and b) solar ORCs. Corresponding maps of operating parameters are generated to facilitate distributed power engineers in the design of economic systems within constraints such as available heat source temperatures, maximum expander inlet pressures imposed, etc. Further, the effect of power scaling on these specific costs is evaluated for ORC capacities between 5 and 500 kWe.