Orientador: Arnaldo Cesar da Silva Walter / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T02:05:23Z (GMT). No. of bitstreams: 1 Chan_WaiNam_D.pdf: 5639561 bytes, checksum: 8279f99a0c7e8cb37a6663e0035244bd (MD5) Previous issue date: 2015 / Resumo: Atualmente o setor de refino de petróleo é responsável por cerca de 5% do total das emissões de CO2 relacionadas ao uso de energia no Brasil. O objetivo principal desta tese é avaliar as opções de mitigação de CO2 e seus respectivos custos para a REPLAN, que é a maior refinaria nacional. A revisão bibliográfica, a obtenção de informações adicionais na refinaria e a análise crítica das informações obtidas possibilitaram realizar uma prospecção de tecnologias de mitigação de emissões de CO2 para a indústria de refino. Através da utilização do conceito de Custo Marginal de Abatimento foi possível realizar a análise econômica das opções de mitigação de CO2 existentes na REPLAN. Os resultados mostram que melhorias de eficiência energética e substituição de combustível representam as estratégias mais promissoras para a redução das emissões de CO2 no curto prazo. Os custos de abatimento estimados são negativos (média de -130 US$/t CO2), o que significa que as medidas já são atrativas e poderiam ser implementadas imediatamente. Entretanto, o potencial global de redução é relativamente baixo (0,23 milhão de t CO2/ano, ou 6% do total das emissões). É mostrado ainda que a técnica de captura e armazenamento de carbono (CCS) oferece potencial para reduções mais significativas de emissões no longo prazo (até 1,62 milhão de t CO2/ano, ou 43% do total das emissões), mas os custos são bem maiores e, no cenário considerado, se situam na faixa de 64-162 US$/t de CO2, dependendo da fonte de emissão de CO2 (regeneradores de unidades de craqueamento catalítico ou unidades de geração de hidrogênio) e da tecnologia considerada para a captura de CO2 (oxi-combustão ou pós-combustão). Nesta tese é mostrado que as oportunidades remanescentes de melhoria de eficiência energética são limitadas na REPLAN. Dessa forma, CCS seria tecnicamente viável para reduzir as emissões de CO2, mas há uma série de questões políticas, legais, financeiras e técnicas que precisam ser superadas. Em caso de um cenário de restrição de emissões de gases de efeito estufa no Brasil, uma opção é considerar uma estratégia de mitigação de CO2 em duas etapas. A implementação de CCS poderia ser adiada para um período após 2020 até que a tecnologia se torne economicamente viável. Finalmente, o estudo de caso da REPLAN pode ser considerado como um plano de ação replicável para outras refinarias brasileiras / Abstract: Currently the oil refining sector is responsible for approximately 5% of Brazilian energy related CO2 emissions. The main objective of this thesis is to evaluate the CO2 mitigation options and their costs to REPLAN, which is the largest national refinery. The literature review, the achievement of additional information at the refinery and the critical analysis of information enabled to conduct a survey of CO2 emissions mitigation technologies for the refining industry. By using the concept of Marginal Abatement Cost it was possible to conduct an economic analysis of existing CO2 mitigation options at REPLAN. The results show that energy efficiency improvements and fuel substitution represent the most promising strategies for reducing CO2 emissions in the short term. The estimated abatement costs are negative (on average, about -130 US$/t CO2), meaning that the measures are already cost-effective and could be implemented immediately. However, the overall abatement potential is relatively low (0.23 million t CO2/year, or 6% of the total emissions). It is further shown that the technique of carbon capture and storage (CCS) offers the potential for more significant emission reductions in the long term (up to 1.62 million t CO2/year, or 43% of the total emissions), but costs are much higher and, in the considered scenario, are in the range of US$ 65-164/t CO2, depending on the CO2 emission source (regenerators of catalytic cracking units or hydrogen production units) and the CO2 capture technology considered (oxyfuel combustion or post-combustion). In this thesis it is shown that remaining opportunities of energy efficiency improvement are limited at REPLAN. Thus, CCS would be technically feasible to reduce CO2 emissions, but there are a number of political, legal, financial and technical issues that must be overcome. In case of a scenario with restriction of greenhouse gas emissions in Brazil, one option is to consider a two-step CO2 mitigation strategy. CCS implementation could be postponed for a period after 2020 until the technology becomes economically viable. Finally, the case study of REPLAN can be considered as a replicable action plan to other Brazilian refineries / Doutorado / Planejamento de Sistemas Energeticos / Doutor em Planejamento de Sistemas Energéticos

Orientador: Sergio Valdir Bajay / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-28T11:43:51Z (GMT). No. of bitstreams: 1 Morais_EversonOdilson_M.pdf: 9230860 bytes, checksum: b4a82810b09398fe97a0d08e02576103 (MD5) Previous issue date: 2015 / Resumo: A energia, seja ela elétrica ou térmica, é um insumo fundamental para qualquer setor da economia. Nas empresas industriais energo-intensivas, em especial, a participação desse insumo nos custos de produção é extremamente significativa e cada vez mais se busca seu uso racional, sem que o processo produtivo seja prejudicado. No Brasil, o setor industrial representa 34% do consumo final de energia elétrica e térmica; deste modo, ações que visam redução do seu consumo energético específico devem ser sempre estimuladas. O Brasil desperdiça todo ano cerca de 10% do total de energia elétrica consumida no país, volume superior ao consumido, por exemplo, pela população total do estado do Rio de Janeiro. Algumas medidas estão sendo adotadas pelo governo a fim de minimizar os desperdícios de energia, através de programas como o Programa Nacional de Conservação de Energia Elétrica (Procel) e os Programas de Eficiência Energética das empresas distribuidoras de energia elétrica, regulados pela Agência Nacional de Energia Elétrica (ANEEL), dentre outros. Este trabalho tem como objetivo analisar a atual sistemática de gestão de energia da maior empresa do segmento petroquímico no Brasil, a Braskem, e elaborar uma proposta para o seu aprimoramento, visando à certificação pela ISO 50001 ¿ Sistema de Gestão da Energia. Para o desenvolvimento do trabalho foi realizada uma análise retrospectiva de como o tema eficiência energética tem sido abordado nos últimos anos na Braskem, até a implantação da atual sistema de gestão de energia, na qual o autor desta dissertação participou, e os ganhos de eficiência energética que este sistema tem propiciado. Também foi realizada consulta entre algumas grandes empresas industriais no país e no exterior, com o intuito de verificar boas práticas de gestão energética que estão sendo desenvolvidas e o que poderiam ser aplicados na Braskem. Nota-se que, apesar dos grandes benefícios que os ganhos de eficiência energética podem propiciar aos consumidores de energia e à sociedade, há ainda muitas barreiras que tem limitado sua aplicação; porém, assim como na Braskem, as grandes empresas energo-intensivas estão cada vez mais buscando formas de reduzir seu consumo específico de energia, aumentando, assim, sua competitividade no mercado / Abstract: Energy, be it electrical or thermal energy, is a fundamental resource in every sector of the economy. In energy-intensive industrial companies, in particular, energy plays an important role in terms of production costs, since this resource impacts significantly the company's bottom-line. Because of that, companies tend to intensely focus on the sustainable use of such a resource without impacting the production process. Since industry accounts for 34% of the final energy consumption in Brazil, actions to reduce its specific consumption should be stimulated. Yearly, 10% of the total electricity consumption in the country is wasted, whose volume is higher than the electricity consumed in the State of Rio de Janeiro. Some measures are being implemented by the government seeking to minimize energy losses, through programs such as the National Electricity Conservation Program (Procel) and the electricity distribution utilities¿ energy efficiency programs, regulated by the National Agency for Electric Energy (ANEEL). This thesis aims at assessing the current energy management system in the largest petrochemical company in Brazil, Braskem, and proposing its upgrade to obtain the ISO 50001 certification on Management of Energy Systems. A retrospective analysis is carried out to show how the energy efficiency issue has been approached at Braskem in the last years, culminating with the adoption of the current energy management system, in which the author of this thesis participated, and the energy efficiency gains this system has provided for. Some large industrial companies in Brazil and abroad were also contacted, in the search for good energy management practices that could be customized for application at Braskem. It can be observed that, even though energy efficiency gains bring large benefits to energy customers and to society, many barriers are still limiting their application. However, such as Braskem, many large energy-intensive companies are seeking to reduce their specific energy consumption, increasing, in this way, their competitive advantage in the market place / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Planejamento de Sistemas Energéticos

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-26T18:26:31Z No. of bitstreams: 1 amandaschelgshornpereira.pdf: 8164581 bytes, checksum: bff8551485b4df0fe3e5788333e7a8b4 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-27T11:07:30Z (GMT) No. of bitstreams: 1 amandaschelgshornpereira.pdf: 8164581 bytes, checksum: bff8551485b4df0fe3e5788333e7a8b4 (MD5) / Made available in DSpace on 2016-01-27T11:07:30Z (GMT). No. of bitstreams: 1 amandaschelgshornpereira.pdf: 8164581 bytes, checksum: bff8551485b4df0fe3e5788333e7a8b4 (MD5) Previous issue date: 2014-07-07 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Devido à redução dos custos de produção no mercado internacional e pelo incentivo ao uso racional dos recursos energéticos, as tecnologias fotovoltaicas apresentam inúmeras possibilidades e boas oportunidades de inovação. Neste sentido, este trabalho é baseado em pesquisa experimental, tendo por objetivo o projeto de um brise-soleil com a utilização de placas fotovoltaicas. Nesta proposição, busca-se aumentar a eficiência energética do módulo fotovoltaico ao se inserir aletas para dissipação de calor. Isto favorece ao resfriamento da superfície posterior do módulo melhorando seu desempenho energético. Para isto, foi realizada revisão detalhada da literatura; identificação das tecnologias utilizadas atualmente; e utilização de software específico para projeto de produto: prototipagem virtual. O processo de projeto foi orientado por metodologia específica da área de desenvolvimento de produtos. Os conceitos elaborados foram validados e ranqueados através do matriz de decisão e por meio de simulação virtual em modelador tridimensional com capacidade de análise de protótipos virtuais. O componente para dissipação de calor foi experimentado em laboratório com auxílio de câmera termográfica, para o registro de variações de temperatura. O brise-soleil fotovoltaico foi projetado em conformidade com o módulo fotovoltaico de modelo SX 120 U da empresa BP Solar. Posteriormente, o projeto foi aplicado em estudo no prédio da Justiça Federal no município de Juiz de Fora (MG). Este estudo foi norteado pelo método prescritivo RTQ-C (2010) – (Requisitos Técnicos da Qualidade para Nível de Eficiência Energética de Edifícios Comerciais, de Serviço e Públicos), onde foi realizada a avaliação da eficiência energética da edificação em sua situação atual, e na situação hipotética, após a experimentação virtual do brise-soleil fotovoltaico na fachada norte. Por fim, destaca-se a colaboração do trabalho para a proposição de soluções que combinam conforto ambiental e eficiência energética em edificações. / Due to the reduction of production costs in the international market and the rational use of energy resources, photovoltaic technologies present many possibilities and good opportunities for innovation. In this sense, this work is based on experimental research, aiming to design a brise-soleil with the use of photovoltaics. In this proposal, we seek to increase the energy efficiency of PV modules by inserting fins for heat dissipation. This favors the cooling of the rear surface of the module improving their energy performance. For this, detailed literature review was conducted; and use of specific software to product design; and virtual prototyping. The design process was driven by a specific methodology in the area of product development. Developed concepts were validated and unranked through the specific decision matrix and through three-dimensional virtual simulation modeler. The component for heat dissipation was tested in the laboratory with the aid of thermographic camera to record temperature changes. Importantly, the brise-soleil PV was designed in accordance with the PV module SX 120 U model company BP Solar. Subsequently, the project was applied to study at the Federal Court building in the city of Juiz de Fora (MG). This study was guided by prescriptive RTQ - C (2010) method, where the rating of the energy efficiency of the building in its current state was performed, and in the hypothetical situation, after the virtual trial brise-soleil PV on the north facade. Finally, there is the collaborative work in proposing solutions that combine environmental comfort and energy efficiency in buildings.

Grandes fachadas envidraçadas têm se tornado comuns em edifícios de escritórios, desconsiderando elementos importantes como as janelas na redução do seu consumo energético, por meio da obtenção da iluminação e ventilação naturais. Dessa forma, o objetivo principal desta pesquisa é avaliar o potencial de economia de energia em edifícios de escritórios por meio da utilização de estratégias de ventilação híbrida, em duas regiões climáticas brasileiras distintas. O método consiste em medições com sensores para aferir dados de temperatura e umidade no momento em que são acionados os condicionadores de ar, a fim de obter a temperatura de setpoint. Tal resultado foi utilizado em simulações computacionais do desempenho térmico e da iluminação natural através dos programas EnergyPlus e Daysim respectivamente. Foi analisado um modelo de edifício de escritórios, com um sistema de iluminação eficiente (dimerizável) em que foram inseridas estratégias de ventilação híbrida, a fim de se obter a influência na economia de energia devido à redução do uso do condicionamento artificial de ar (nos períodos em que isso foi possível). Os resultados apresentaram uma redução no consumo do ar condicionado em torno dos 30%, enquanto que o impacto da ventilação híbrida no consumo de energia total do edifício apresentou-se na faixa dos 12%. Todavia, com a utilização de tais estratégias alcançou-se uma redução de até 84% do desconforto térmico nos ambientes. Como conclusão do trabalho tem-se que, utilizando-se um sistema de iluminação natural eficiente, o impacto da ventilação híbrida no potencial de economia de energia, dependendo do caso, pode não ser tão expressivo, ao passo que a redução no nível de desconforto térmico é bastante significativa. / Large glazed facades have become common in office buildings and important elements, like windows to obtain natural lighting and ventilation to reduce their energy consumption have been ignored. This dissertation evaluates the potential of energy savings in office buildings through the use of hybrid ventilation strategies in two different Brazilian climatic regions. The method consists in measuring sensors for collecting humidity and temperature data at the time air conditioners are started so as to obtain the setpoint temperature. The results were used in computer simulations of both thermal performance and daylighting through EnergyPlus and Daysim software, respectively. A model of the office building, with efficient lighting (dimmable), was analyzed. Hybrid ventilation strategies were adopted for verifying the influence on energy savings due to a reduced use of artificial air conditioning (in periods in which it was possible). The results show a 30% reduction in the consumption of air conditioning and a 12% impact of hybrid ventilation on the total energy consumption of the building. However, such strategies caused an 84% reduction in the thermal discomfort in the environment. According to the results, the impact of hybrid ventilation on the potential energy savings by the use of efficient daylighting, in some cases, may not be so significant, whereas the reduction in the level of thermal discomfort is quite significant.

Le rapport entre TIC, environnement et efficacité énergétique est sujet d’un grand nombre de polémiques. Ces concepts sont rarement associés, surtout pour les petites économies émergentes. Pourtant, chacun d’entre eux a des impacts considérables sur l’autre. Les impacts négatifs des TIC sur l’environnement sont très divers, de la même façon, l’usage et la diffusion des TIC peuvent profiter pour l’environnement. Ce travail propose d’approfondir l’étude des impacts des TIC sur la consommation énergétique et les émissions de GES, à l'échelle macroéconomique pour le cas de la Tunisie. Le contexte général de cette thèse s'articule autour de la relation entre l'environnent et la théorie des innovations, alors que le contexte spécifique se concentre plus particulièrement sur la consommation énergétique des TIC. Notre approche s’est insérée dans le cadre de la théorie de l’innovation et le fondement économique de l’usage des nouvelles technologies, plus précisément à l’intersection de l’économie industrielle et de l'économie de l'environnement. Notre recherche a abordé trois principaux aspects: théorique, descriptif et empirique. Tout d’abord, elle a traité la théorie des innovations environnementales et ses relations avec les technologies à usage général et en particulier les TIC. Deuxièmement, cette thèse nous a permis d’élaborer des analyses descriptives détaillées, fondées sur les données et les statistiques issues de la Banque mondiale et autres institutions. Troisièmement, un ensemble de tests statistiques et de modèles économétriques rigoureux ont été appliqués pour déterminer le lien entre l'investissement dans les TIC et la performance énergétique de la Tunisie. / The relationship between ICT, environment and energy efficiency causes a lot of controversies. Theseconcepts are rarely associated, especially for smaller emerging economies. Yet each has a significant impacton the other. The negative effects of ICT on the environment are various, in the same way, use and diffusionof ICT can also benefit the environment. This PhD thesis put forward further study impacts of ICT on energyconsumption and emissions of greenhouse gases, at the macro level for the case of Tunisia. The generalcontext of this thesis focuses on the relationship between the environment and the innovation theory, whilethe specific context focuses specifically on the energy consumption of ICT. Our approach is inserted underthe theory of innovation and economic basis for the use of new technologies, specifically at the intersectionof industrial economics and environmental economics. Our research focused on three main aspects:theoretical, empirical and descriptive. Firstly, this study handled the theory of environmental innovationsand its relationship with general purpose technology and ICT especially. Secondly, this thesis has allowed usto develop a detailed descriptive analyses based on the data and statistics from the World Bank, and otherinstitutions. Thirdly, a set of statistical tests and rigorous econometric models were applied to determine thelink between ICT investment and energy efficiency in Tunisia.

The aim of this project is to examine the energy consumption of Nåntuna elementary school in Uppsala, in order to suggest improvements, making the building more energy efficient. The aim also includes calculating savings and the pay-off time for each energy reducing measure. This project is performed together with Skolfastigheter and STUNS on the initiative of Uppsala Energy Stories. The study includes an examination of the energy consumption of the building, energy calculations and a proposal of actions for improvements with cost estimations and pay-off time calculated. The conclusion includes performing following actions: installing low-flushing taps, changing to LED lighting with attendance time and daylight control, replacing the ventilation system, lowering the air flows in the ventilation and also installing solar power. Calculating both the best and the worst case scenario gives an interval for possible outcomes in the result. According to calculations, installing low-flushing taps will have a pay-off time of 1.7-2.3 years and a yearly saving of 1 300-1 800 kr, LED lighting a pay-off time of 25.5-31 years and savings of 24 700-29 900 kr per year, ventilation a pay-off time of 6-7.7 years and a yearly saving of 65 400-76 400 kr and lastly an installation of solar power a pay-off time of 5.9-9.6 years and savings of 24 000-30 000 kr per year.

Multi-tier heterogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-tier network architecture known as phantom cellular networks. The optimization framework includes both EE and SE. First, we consider sparsely deployed cells experiencing negligible interference and assume perfect channel state information (CSI). For this setting, we propose an algorithm that finds the SE and EE resource allocation strategies. Then, we compare the performance of both design strategies versus number of users, and phantom cells share of the total available resource units (RUs). We aim to investigate the effect of some system parameters to achieve improved SE performance at a non-significant loss in EE performance, or vice versa. It is found that increasing phantom cells share of RUs decreases the SE performance loss due to EE optimization when compared with the optimized SE performance. Second, we consider the densely deployed phantom cellular networks and model the EE optimization problem having into consideration the inevitable interference and imperfect channel estimation. To this end, we propose three resource allocation strategies aiming at optimizing the EE performance metric of this network. Furthermore, we investigate the effect of changing some of the system parameters on the performance of the proposed strategies, such as phantom cells share of RUs, number of deployed phantom cells within a macro cell coverage, number of pilots and the maximum power available for transmission by the phantom cells BSs. It is found that increasing the number of pilots deteriorates the EE performance of the whole setup, while increasing maximum power available for phantom cells transmissions reduces the EE of the whole setup in a less severe way than increasing the number of pilots. It is found also that increasing phantom cells share increases the EE metric in the dense deployment case. Thus, it is always useful to allocate most of the network RUs to the phantom cells tier.

Built with nanomagnets, a spintronic device called the all-spin logic (ASL) device carries information with only spin currents, resulting in a low power supply--10 mV. This voltage is 100 times smaller than the conventional CMOS devices (usually 0.8~1V). The potential for improved energy efficiency made possible by the low operating voltage of ASL makes it one of the most promising devices among its post-CMOS competitors. The basic working principles of ASL device are introduced in this thesis and two complementary approaches to studying energy efficiency of computation are applied to a common set of ASL circuits: (1) a circuit simulation approach that provides efficiency estimates for specific ASL circuit realizations, and (2) a physical-information-theoretic approach that reveals fundamental efficiency bounds for ASL circuits as limited by irreversible information loss. The results of this study support the expectation that the energy efficiency of computation in ASL can far exceed that of CMOS. However, it also reveals that ASL efficiencies--shown to exceed fundamental limits by many orders of magnitude in the ASL implementations studied here--are unlikely to approach fundamental limits because of the unavoidable energetic overhead cost of maintaining spin currents.

There has been significant growth in both utility-scale and residential-scale solar installa- tions in recent years, driven by rapid technology improvements and falling prices. Unlike utility-scale solar farms that are professionally managed and maintained, smaller residential- scale installations often lack sensing and instrumentation for performance monitoring and fault detection. As a result, faults may go undetected for long periods of time, resulting in generation and revenue losses for the homeowner. In this thesis, we present SunDown, a sensorless approach designed to detect per-panel faults in residential solar arrays. SunDown does not require any new sensors for its fault detection and instead uses a model-driven ap- proach that leverages correlations between the power produced by adjacent panels to de- tect deviations from expected behavior. SunDown can handle concurrent faults in multiple panels and perform anomaly classification to determine probable causes. Using two years of solar generation data from a real home and a manually generated dataset of multiple solar faults, we show that our approach has a MAPE of 2.98% when predicting per-panel output. Our results also show that SunDown is able to detect and classify faults, including from snow cover, leaves and debris, and electrical failures with 99.13% accuracy, and can detect multi- ple concurrent faults with 97.2% accuracy.

Jellyfish have inhabited this planet for millions of years and are the oldest known metazoans that swim using muscles. They are found in freshwater sources and in oceans all over the world. Over millions of years of evolution, they have adapted to survive in a given environment. They are considered as one of the most energy efficient swimmers. Owing to these characteristics, jellyfish has attracted a lot of attention for developing energy efficient unmanned undersea vehicles (UUVs). The goal of this thesis is to provide understanding of the different physical mechanisms that jellyfish employs to achieve efficient swimming by using analytical and computational models. The models were validated by using the experimental data from literature. Based upon these models refinements and changes to engineering vehicles was proposed that could lead to significant enhancement in propulsion efficiency. In addition to the propulsion, the thesis addresses the practical aspects of deploying a jellyfish-inspired robotic vehicle by providing insights into buoyancy control and energy generation. The thesis is structured in a manner such that propulsive and structural models inspired from the natural animal were systematically combined with the practical aspects related to ionic diffusion driven buoyancy control system and thermal -- magnetic energy harvesting system. Jellyfish morphology, swimming mechanism and muscle architecture were critically reviewed to accurately describe the natural behavior and material properties. We provide full understanding of mesoglea, which plays most significant role towards swimming performance, in terms of composition, mechanical properties and nonlinear dynamics. Different jellyfish species exhibit different microstructure of mesoglea and thus there is a wide variety of soft materials. Mechanical properties of collagen fibers that form the main constituent toward imparting elasticity to mesoglea were reviewed and analyzed. The thesis discusses the theoretical models describing the role of structure of mesoglea towards its mechanical properties and explains the variation occurring in stiffness under given experimental environment. Muscle architecture found in jellyfish, nerve nets and its interconnection with the muscles were investigated to develop comprehensive understanding of jellyfish propulsion and its reaction to external stimuli. Different muscle arrangements were studied including radial, coronal muscle, and coronal-muscles-with-breaks in-between them as observed in Cyanea capillata. We modeled these muscle arrangements through finite element modeling (FEM) to determine their deformation and stroke characteristics and their overall role in bell contraction. We found that location and arrangement of coronal muscle rings plays an important role in determining their efficient utilization. Once the understanding of natural jellyfish was achieved, we translated the findings onto artificial jellyfish vehicle designed using Bio-inspired Shape Memory Alloy Composite (BISMAC) actuators. Detailed structural modeling was conducted to demonstrate deformation similar to that of jellyfish bell. FEM model incorporated hyperelastic behavior of artificial mesoglea (Ecoflex-0010 RTV, room temperature vulcanizing silicone with shore hardness (0010)), experimentally measured SMA temperature transformation, gravity and buoyancy forces. The model uses the actual control cycle that was optimized for driving the artificial jellyfish vehicle "robojelly". Using a comparative analysis approach, fundamental understanding of the jellyfish bell deformation, thrust generation, and mechanical efficiency were provided. Meeting energy needs of artificial vehicle is of prime importance for the UUVs. Some jellyfish species are known to use photosynthesis process indirectly by growing algae on their exumbrella and thereby utilizing the sunlight to generate energy. Inspired by this concept, an extensive model was developed for harvesting solar energy in underwater environment from the jellyfish bell structure. Three different species were modeled for solar energy harvesting, namely A.aurita, C.capillata and Mastigia sp., using the amorphous silicon solar cell and taking into account effect of fineness ratio, bell diameter, turbidity, depth in water and incidence angle. The models shows that in shallow water with low turbidity a large diameter vehicle may actually generate enough energy as required for meeting the demand of low duty cycle propulsion. In future, when the solar energy harvesting technology based upon artificial photosynthesis, referred to as "dye-sensitized solar cells", matures the model presented here can be easily extended to determine its performance in underwater conditions. In order to supplement the energy demand, a novel concept of thermal -- magnetic energy harvesting was developed and extensively modeled. The proposed harvester design allows capturing of even small temperature differences which are difficult for the thermoelectrics.  A systematic step-by-step model of thermo-magnetic energy harvester was presented and validated against the experimental data available in literature. The multi-physics model incorporates heat transfer, magnetostatic forces, mechanical vibrations, interface contact behavior, and piezoelectric based energy converter. We estimated natural frequency of the harvester, operating temperature regimes, and electromechanical efficiency as a function of dimensional and physical variables. The model provided limit cycle operation regimes which can be tuned using physical variables to meet the specific environment. Buoyancy control is used in aquatic animals in order to maintain their vertical trajectory and travel in water column with minimum energy expense. Some crustaceans employ selective ion replacement of heavy or lighter ions in their dorsal carapace. A model of a buoyancy chamber was developed to achieve similar buoyancy control using electro-osmosis. The model captures all the essential ionic transport and electrochemistry to provide practical operating cycle for the buoyancy engine in the ocean environment. / Ph. D.