Organic Rankine Cycle (ORC) heat engines convert low-grade heat to other forms of energy such as electrical and mechanical energy. They achieve this by vaporizing and expanding the organic fluid at high pressure, turning the turbine which can be employed to run an alternator or any other mechanism as desired. Conventional Rankine Cycles operate with steam at temperatures above 400 ℃. The broad aspect of the research focussed on the generation of electricity to cater for household needs. Solar energy would be used to heat air which would in turn heat rocks in an insulated vessel. This would act as an energy storage in form of heat from which a heat transfer fluid would collect heat to supply the ORC heat engine for the generation of electricity. The objective of the research was to optimize power output of the ORC heat engine operating at temperatures between 25℃ at the condenser and 90 to 150℃ at the heat source. This was achieved by analysis of thermal energy, mechanical power, electrical power and physical parameters in connection with flow rate of working fluid and heat transfer fluids.

The technology of cogeneration is reviewed through an examination of the prime movers most commonly used for this purpose in industrial and commercial facilities. The systems characteristics which are of particular importance to the congeneration application are emphasized along with the advantages and limitations of each. A comparative examination of the methods selected for use in the evaluation of profitability in cogeneration systems is presented. The examination focuses on the interpretation of the projections made by each method and their implications for the decision to adopt cogeneration. A computer simulation model is utilized to perform a sensitivity study in order to identify the key variables determining economic viability of cogeneration. Employing a gas turbine system as a representative installation, the variables used in the sensitivity study are presented along with the justification for the assignment of the baseline and study range values. A simplified method for analyzing the profitability of cogeneration systems is developed. The technique is specifically tailored to gas turbine based cogeneration which is the technology most commonly proposed for moderate size facilities. The significance of the incremental energy consumption factor as a determinant of profitability is investigated. The application of the simplified method for comparative studies of different gas turbine systems is described and the results compared to projections made by the simulation model. Finally, the simplified method is utilized to examine the implications of regional fuel price differences and the implications of natural gas price deregulation on the profitability of gas turbine cogeneration.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by Catherine E. Teague. / M.S.

Thesis (M.S.)--Ohio University, June, 1995. / Title from PDF t.p.

Thesis (DTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / Fuel cells are among power generation technologies that have been proven to reduce greenhouse gas emissions. They have the potential of being one of the most widely used technologies of the 21st century, replacing conventional technologies such as gas turbines in stationary power supplies, internal combustion engines in transport applications and the lithium-ion battery in portable power applications. This research project concentrates on the performance analysis of a micro-cogeneration system based on a high temperatureproton exchange membrane (HT-PEM) fuel cell through modelling and parametric analysis. A model of a 1kWe micro-cogeneration system that consists of a HT-PEM fuel cell, a methane steam reformer (MSR) reactor, a water-gas-shift (WGS) reactor, heat exchangers and an inverter was developed. The model is coded/implemented in gPROMS Model Builder, an equation oriented modelling platform. The models predictions for the HTPEM fuel cell, MSR and WGS, and the whole system were validated against experimental and numerical results from literature. The validation showed that the HT-PEM fuel cell model was able to predict the performance of a 1kWe fuel cell stack with an error of less than 6.4%. The system model is rstly used in a thermodynamic analysis of the fuel processor for a methane steam reforming process and investigated in terms of carbon monoxide produced. The combustor fuel and equivalence ratios were shown to be critical decision variables to be considered in order to keep the carbon monoxide from the fuel processor at acceptable levels for the fuel cell stack.

Orientador: Luiz Carlos Pereira da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-10T03:25:09Z (GMT). No. of bitstreams: 1 Marques_FredericoAugustoSpolidorio_M.pdf: 3699527 bytes, checksum: fee04cbb6876f5ce62626058ebc660e7 (MD5) Previous issue date: 2007 / Resumo: Este projeto busca relacionar diversos aspectos interdisciplinares envolvidos em uma central de co-geração de energia elétrica. Motivado pela crescente inserção de centrais de geração distribuída operando de forma ilhada ou paralela ao sistema, foram desenvolvidos modelos mecânicos (térmicos e dinâmicos) e elétricos buscando representar os diversos equipamentos envolvidos em uma central de geração em um nível industrial. Baseado nesta concepção, optou-se pela geração de energia através de máquinas térmicas (turbinas a vapor) impulsionadas pela energia proveniente da queima de biomassa restante de diferentes processos industriais. Os modelos teóricos aqui representados foram numericamente simulados com parâmetros obtidos em um estudo de caso real. Seus resultados foram então comparados qualitativamente e quantitativamente contra as variáveis reais do processo analisado. Ao consolidar esta ferramenta de estudo, o simulador mostrou-se eficiente no treinamento de operadores de casas de forças, sendo capaz de esclarecer as interferências entre o nível de carga com as demais variáveis envolvidas em seu processo / Abstract: This project intends to gather several interdisciplinary aspects common to a co-generation power plant. Driven by the increasing amount of distributed generation units operating on island or parallel mode with the network, some mechanical (thermo and dynamic) and electrical models were developed in order to represent the equipments usually installed on an industrial size power station. Based on this concept, the more convenient option was to proceed the evaluation through turbo machinery (steam turbine) driven by the energy acquired from the heat power on burning byproducts of industrial processes. The theoretical models were simulated with parameters obtained from a real case study. The results were then finally compared with real process information acquired from field research. In order to consolidate this computational tool, the simulator has shown efficient results on training power station operators on clarifying the impacts of load level on the other relevant variables on their processes / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

Orientador: Silvia Azucena Nebra de Perez / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-15T08:40:40Z (GMT). No. of bitstreams: 1 Alves_LourencoGobira_D.pdf: 2286993 bytes, checksum: 9be242b04e4640bec3bb9397c2679294 (MD5) Previous issue date: 2007 / Resumo: A alta dos preços do petróleo aliada ao aumento da participação do gás natural na matriz energética nacional força a sociedade a pensar em usos mais racionais para o gás, tanto por necessidades econômicas quanto ambientais. O hidrogênio é apontado por alguns autores como combustível do futuro, portanto aproveitar o gás natural como matéria-prima para produzir hidrogênio é uma das alternativas para melhor uso do gás. Este trabalho faz a análise exergoeconômica de dois processos básicos de produção de hidrogênio a Reforma a Vapor do Metano, SMR, e a Reforma Autotérmica do Metano, AtR, usando a Teoria do Custo Exergético, TEC, e a Análise Funcional, AF. É proposta a introdução de cogeração usando uma turbina movida a gás natural e outra movida a gás de síntese para os dois processos, gerando quatro casos de estudo onde a possibilidade de produzir excedentes para venda foi considerada. Foi feita a otimização dos processos com dois objetivos: busca da maior produção de hidrogênio e busca da menor geração de irreversibilidade. Os resultados mostram que a cogeração é uma possibilidade a ser estudada com cuidado, pois o custo de produção da eletricidade precisa ser competitivo com o mercado energético brasileiro. Os quatro casos de estudo mostraram boa flexibilidade para otimização dos processos / Abstract: The prices of Petroleum allied to the increase of the participation of the Natural Gas in the national energy matrix have forced the society to search for more rational uses for the gas by economic and environmental reasons. According to some authors, hydrogen is the fuel of the future and the production of hydrogen from natural gas is an alternative to improve the gas uses. This work performs an exergoeconomic analysis of two basic processes to produce hydrogen, Stem Methane Reforming, SMR, and Autothermal Reforming, AtR, using the Theory of Exergetic Cost, TEC, and the Functional Analysis, AF. Two cogeneration possibilities in the processes are also considered, resulting in four study cases with the possibility of producing surplus of electric energy to sell. And an optimization study is performed to improve the hydrogen production and reduce the irreversibility. The results shown that cogeneration is a useful possibility but must be applied according to the Brazilian energy market. The optimization process increased the results in the four cases / Doutorado / Termica e Fluidos / Doutor em Engenharia Mecânica

Thesis (doctoral)--Freie Universität, Berlin, 2007. / Includes bibliographical references.

This dissertation describes methods developed for analysis of the New York City energy system. The analysis specifically aims to consider the built environment and its' impacts on greenhouse gas (GHG) emissions. Several contributions to the urban energy systems literature were made. First, estimates of annual energy intensities of the New York building stock were derived using a statistical analysis that leveraged energy consumption and tax assessor data collected by the Office of the Mayor. These estimates provided the basis for an assessment of the spatial distribution of building energy consumption. The energy consumption estimates were then leveraged to estimate the potential for combined heat and power (CHP) systems in New York City at both the building and microgrid scales. In aggregate, given the 2009 non-baseload GHG emissions factors for electricity production, these systems could reduce citywide GHG emissions by 10%. The operational characteristics of CHP systems were explored further considering different prime movers, climates, and GHG emissions factors. A combination of mixed integer linear programing and controlled random search algorithms were the methods used to determine the optimal capacity and operating strategies for the CHP systems under the various scenarios. Lastly a multi-regional unit commitment model of electricity and GHG emissions production for New York State was developed using data collected from several publicly available sources. The model was used to estimate average and marginal GHG emissions factors for New York State and New York City. The analysis found that marginal GHG emissions factors could reduce by 30% to 370 g CO₂e/kWh in the next 10 years.

Orientadores: Silvia Azucena Nebra e Elizabeth Ferreira Cartaxo / Tese (doutorado) - Universidade Estadual se Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-04T02:01:08Z (GMT). No. of bitstreams: 1 Cruz_RicardoWilsonAguiarda_D.pdf: 17244783 bytes, checksum: a03d0eedccd3e72d383d8e704276c5cf (MD5) Previous issue date: 2004 / Resumo: Neste trabalho procurou-se apresentar um panorama da geração isolada de energia elétrica pelo Sistema CEAM, quanto às suas características técnicas e econômicas, e do mercado de conservação de pescado do interior do Estado do Amazonas, como bases para desenvolver um método que permita avaliações da introdução de cogeração nessas usinas, visando a produção de mo e gelo, como forma de elevação da lucratividade. Para tanto é mostrado que uma usina autônoma produzindo apenas energia elétrica no cenário interiorano amazonense não tem como ser lucrativa no cenário atual. Foi utilizado como ferramentas básicas elementos da teoria dos motores de combustão interna sob carga variável, teoria das máquinas de remgeração por absorção água-amônia e métodos termoeconômicos baseados na primeira e segunda lei da Termodinâmica. O quadro típico das usinas do interior é mostrado por dados coletados em visitas a cinco usinas, sendo duas delas de outros estados que não o Amazonas, mas que conservam características comuns com as usinas amazonenses. O mercado de pescado é discutido sobre dados bibliográficos. E, do cruzamento desses quadros, são inferidas características da interdependência entre remgeração industrial e energia elétrica / Abstract: This investigation shows a panorama of the isolated power generation of the Amazon State CEAM System regarding its technical and economic characteristics, as well as the problems of the refrigeration facilities of the tishing industry of inland the State, focusing to develop methods to evaluate the introduction of cogeneration in the generation system to the enhance its protitability. Meanwhile, it is shown that a autonomous power station can not expect to become protitable in the Amazonian nowadays scenario if it uniquely produces electric energy. To achieve this objective the main theoretical background were elements of the theory of internal combustion engines under variable charge, the theory of aquammonia absorption refiigeration devices, and methods belonging to thermoeconomics based on tirst law and second law of thermodynamics. A typical profile of the stations of the CEAM System is showed by collected data on tive autonomous power stations among the Northern Brazilian autonomous power grid. The tive power stations preserve common characteristics among them. The market of the tishing industry is showed by bibliography surveyed data. These data made possible to infer the profound relationship between refiigeration and electric energy / Doutorado / Planejamento de Sistemas Energeticos / Doutor em Planejamento de Sistemas Energéticos