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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

A decision support system for conduct hydropower development

Loots, Ione January 2013 (has links)
Cheap and reliable electricity is an essential stimulus for economic and social development. Currently fossil fuels are used for the majority of global electricity generation, but energy shortages and pressure on all industries to reduce CO2 emissions provide incentives for growing emphasis on the development of alternative energy-generation methods. Presently hydropower contributes about 17% of global energy generation, which is only a fraction of its total potential. In Africa only 5% of its estimated hydropower potential has been exploited, making it the most underdeveloped continent in terms of hydropower. An often overlooked source of hydropower energy is found in conduits, where pressure-reducing stations (PRSs) are installed to dissipate excess energy. The energy dissipated by these devices can instead be captured as hydroelectricity if turbines are installed in the conduits, either by replacing pressure-reducing valves (PRVs) with a turbine, or by installing the turbine in parallel with the PRV. An initial scoping investigation indicated that significant potential exists for small-scale hydropower installations in water-distribution systems in South Africa. Almost all of the country’s municipalities and water-supply utilities have pressure-dissipating stations in their water-distribution systems, where hydropower potential may exist. This dissertation reflects the development of a Conduit Hydropower Decision Support System (CHDSS), summarised in a series of flow diagrams that illustrate the developmental process (Figure i(a) provides an example). A Conduit Hydropower Development (CHD) Tool was developed to facilitate the calculation of necessary factors (the Phase 1 Economic Analysis is shown in Figure i(b)). The objective of this CHDSS was to assist municipalities and engineers in identifying conduit hydropower potential in South Africa and to provide proper guidance for the development of potential sites. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Civil Engineering / Unrestricted
22

Evaluation and proposed development of the municipal solid waste management system in Mexico City

Escamilla Garcia, Pablo Emilio January 2015 (has links)
The work reported involves the evaluation of technologies and management systems applied to Municipal Solid Waste (MSW). The study focuses on Mexico City, which with a population of approximately 9 million inhabitants and an estimated daily generation of 13,000 tonnes of waste, is encountering extreme waste management issues. The structures and public policies designed to provide waste management services have proved inadequate in relation to high rates of population growth and intensive business activities. The significant increase in demand has led the government of Mexico City to base public services on rudimentary techniques using obsolete equipment. The research approaches the problem through the analysis of several different aspects: (1) a comprehensive literature review of waste management including technologies and legal frameworks; (2) a general overview of the main demographic, geographic and economic aspects of Mexico City; (3) an extensive analysis of historic and future waste generation profiles and composition of waste in Mexico City; (4) an evaluation of the current status of the waste management system, including programmes, plans, facilities and infrastructure; and (5) a comparative study of the waste management system of Mexico City and the systems of selected international cities. The evaluation resulted in the identification of the following significant issues: (1) limitations in legislation related to waste management and environmental laws; (2) high population growth and increasing business activity, which contribute escalating generation of MSW; (3) ineffective public policies focused on waste management; (4) significant gaps in low levels of recycling activities; (5) obsolescence of equipment, infrastructure and facilities; (6) lack of diversification in treatment methods for MSW; and (7) failure to exploit market opportunities in the waste management sector. In addition to the evaluation of the system in Mexico City, the analysis of waste management systems in selected international cities allowed the author to identify key factors in order to develop integrated proposals. The analysis highlighted significant aspects including: legal frameworks, the participation of the private sector, waste hierarchy, and guiding principles for plans and programmes. The information enabled the design of a proposed development plan of a comprehensive waste management system in Mexico City through two main proposals. Firstly, an integrated programme for waste management in Mexico City was developed to provide feasible long-term strategies in the field of waste management. The specific objectives, goals, actions, responsibilities and time scales were defined in order to provide concrete activities under specific fields of operation. Secondly, a project to obtain funding for technology transfer structured according to technical, market and economic studies, was elaborated. The guide is aimed to exemplify an investment project through the analysis of a feasibility study related to generation of energy from biogas in a controlled landfill in Mexico City. The process may be adapted to the acquisition of technology in different sectors of the waste management process.
23

Sistema aberto de aquisição de dados meteorológicos para caracterização de recursos eólicos / An open source system for wind resource assessment

Ferraz, Douglas Rocha, 1984- 26 August 2018 (has links)
Orientador: Yaro Burian Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-26T17:40:03Z (GMT). No. of bitstreams: 1 Ferraz_DouglasRocha_M.pdf: 8421723 bytes, checksum: f650d1c3f8022b8a222f806b04eb0834 (MD5) Previous issue date: 2014 / Resumo: O sistema construído nesta tese estima a geração elétrica em determinado local passível de instalação de uma usina de geração eólica. Sua arquitetura utiliza um processador que recebe dados de uma estação meteorológica de baixo custo e as envia para um servidor na nuvem. Este servidor analisa os dados e as projeções de geração eólica podem ser estimadas em tempo real / Abstract: The following thesis describes the construction and implementation of an open-source wind resource assessment system. The architecture uses an embedded processor that fetches environmental data from a low-cost weather station, and sends it to a cloud server where analyses such as projections of energy generation potential can be made in real time. The authors believe such a system can facilitate the inexpensive assessment of wind resources, especially in developing and transition economies, and thereby contribute to the development of renewable energy systems / Mestrado / Automação / Mestre em Engenharia Elétrica
24

Energia solar térmica e fotovoltaica em residências : estudo comparativo em diversas localidades do Brasil / Solar thermal and photovoltaics in houses : a comparative study in several locations in Brazil

Castro, Rodolfo Damásio de, 1990- 27 August 2018 (has links)
Orientador: Ennio Peres da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T02:08:03Z (GMT). No. of bitstreams: 1 Castro_RodolfoDamasiode_M.pdf: 3152478 bytes, checksum: a4e0e80e4ac1f8804a7b3aa8589139b4 (MD5) Previous issue date: 2015 / Resumo: A busca por meios de geração de energia para atender às necessidades humanas com menores impactos sociais e ambientais é constante. A geração de energia elétrica por meio de fontes renováveis na forma distribuída, ou não centralizada, é um meio ou método de minimizar tais impactos. O objetivo da pesquisa foi analisar a viabilidade econômica, frente a tarifa de energia elétrica das concessionárias locais, da utilização de sistemas de geração solar em residências brasileiras situadas nas capitais dos estados, na capital federal, Brasília e na cidade de Campinas (SP). Diferentes situações de dimensionamento foram utilizadas para dois tipos de sistemas: um sistema fotovoltaico puro, para atender toda a necessidade energética da residência, incluindo o chuveiro elétrico, e um sistema solar híbrido, composto por aquecimento solar para atender a demanda por água quente no banho em conjunto com geração fotovoltaica para atender as necessidades em equipamentos elétricos. As situações de dimensionamento utilizadas foram três, onde em cada uma o sistema fotovoltaico foi projetado para uma determinada produção de energia. Os sistemas fotovoltaico e de aquecimento solar foram dimensionados com o auxílio dos softwares PVSyst e Dimensol, respectivamente. O custo total dos sistemas foi estimado a partir de pesquisa em lojas com endereço eletrônico na rede de computadores e de orçamentos fornecidos por empresas do ramo. Determinou-se o preço final da energia elétrica convencional para todas as cidades a partir da tarifa definida pela ANEEL, do valor médio do PIS efetivo cobrado pelas concessionárias e da alíquota de ICMS que os governos estaduais recolhem. Após realizados os cálculos, chegou-se ao resultado de que somente nas cidades de Macapá (AP) e Boa Vista (RR), devido principalmente ao baixo custo das tarifas de energia elétrica, o usuário não economizaria com a instalação dos sistemas. Porém, em cidades de elevada tarifa, como Belém (PA) e Belo Horizonte (MG), o usuário pagaria cerca de R$ 0,30 por quilowatt hora consumido a menos / Abstract: The search for power generation means to meet human needs with lower social and environmental impacts is constant. The distributed generation of electricity by renewable energies is a method to minimize those impacts. The research aimed to analyze the economic viability against local electricity tariff of the use of solar power generation systems in Brazilian households located in the capitals of the states, in the federal capital, Brasilia, and in the city of Campinas (SP) Different sizing situations were used for two types of systems: a pure PV system to meet all the energy needs of the residence, including electric shower, and a hybrid solar system, consisting of solar heating to meet the demand for hot water in the bath together with photovoltaic generation to meet the needs in electrical equipment. Sizing situations used were three, where in each one the PV system is designed for a certain production of energy. The photovoltaic systems and solar heating were sized with the help of the softwares PVSyst and Dimensol, respectively. The total cost of the systems was estimated by a research in webstores and budgets provided by companies in the field. Was determined the final price of conventional electricity to all cities from the tariff set by ANEEL, the average value of the effective PIS charged by concessionaires and ICMS aliquot that state governments collect. After performing the calculations, came to the result that only the cities of Macapa (AP) and Boa Vista (RR), mainly due to the low cost of electricity tariffs, the user does not save due to the installation of the systems. However, in cities of high tariff, as Belém (PA) and Belo Horizonte (MG), the user would save about R$ 0.30 per quilowatt-hour / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Planejamento de Sistemas Energéticos
25

Větrné stroje pro obydlené oblasti / Wind machines for urban areas

Linda, Jakub January 2020 (has links)
The submitted diploma thesis deals with wind machines in densely populated areas. The aim of the work is to design a appropriate wind machine for use on the roofs of buildings, including all the specifics that the air flow in the city may contain. At the beginning, the work focuses on the production of electricity in cities in general, which results in an ideal system of obtaining energy for households. Furthermore, the work deals with the wind in general, where all its specifics are taken over. A very important part of the work is the study of the specifics of air flow in the urban environment together with the numerical simulation of this flow, which results in certain regularities of the location of wind machines on the roofs of buildings. The work then passes to a search of used wind machines, from which the most suitable candidate for use in cities is subsequently selected. The last part of the work is the design of the machine itself for a specific location. In this chapter, the design wind speed is determined from the measured data, which is later followed by the calculation of the geometry of the blades, and finally its benefits and advantages are determined from the properties of the wind machine
26

Laboratory Load-Based Testing, Performance Mapping and Rating of Residential Cooling Equipment

Li Cheng (9593063) 16 December 2020 (has links)
<div>In the U.S., unitary residential air conditioners are rated using standard AHRI 210/240 that is inadequate to credit equipment with advanced controls and variable-speed components since the ratings are based on results of steady-state laboratory tests. Contrarily, a load-based testing and rating approach is presented in this work that can capture equipment performance with its integrated controls and thermostat responses that is more representative of the field. In this approach, representative building sensible and latent loads are emulated in a psychrometric test facility at different indoor and outdoor test conditions utilizing a virtual building model. The indoor test room conditions are continuously adjusted to emulate the dynamic response of the virtual building to the test equipment sensible and latent cooling rates and the equipment dynamic response is measured. Meanwhile, the inlet temperatures to the test equipment thermostat are independently controlled to track the same virtual building response using a thermostat environment emulator that encloses the test thermostat, that provides typical flow conditions and of which the design and control are presented in this work. Climate-specific cooling seasonal performance ratings can be determined by propagating load-based test results through a temperature-bin method to estimate a seasonal coefficient of performance (SCOP). In addition, a next-generation rating approach is developed that extends load-based testing for performance mapping, such that the SCOP can be obtained using building simulations that incorporate specific building types, climates and an equipment-specific performance map. </div><div> </div><div>In this work, the proposed approaches were implemented to test and rate a variable-speed residential heat pump operating in cooling mode. Trained with results from only 12 load-based test intervals carried out using the test equipment, a quasi-steady-state mapping model was able to map the equipment performance across almost the entire operating envelope within $\pm10\%$ errors and the $R^2$ values were very close to 1. Using the identified performance map, the next-generation SCOP was obtained based on an annual simulation deployed in EnergyPlus, where the map was coupled to a typical single-family building in Albuquerque,NM. Compared to the temperature-bin-based rating, this simulation-based rating is able to comprehensively and appropriately reflect equipment annual field performance associated with a specific building type and climate, as the rating is extended from automated laboratory load-based testing and performance mapping.</div>
27

Off-grid portable production and distribution of sustainable energy : A product service system solution developed for the energy market

Andersson, Karl-Henrik, Liedman, Stefan January 2022 (has links)
Background. At the year of 2021, 770 million people worldwide were living without access to electricity. In parallel with this, electrification of vehicles and other equipment constantly increases which results in a demand for access to reliable off-grid energy to allow for operation in remote locations or places without sufficient energy infrastructure due to external factors such as natural disasters. As the use of fossil fuels is predicted to decrease, the need for sustainable energy production utilizing renewable energy sources has proved to be critical. The combination of these factors results in a need for the development of sustainable off-grid energy systems utilizing renewable energy sources.  Objectives. The objective of this thesis is to highlight needs and present a developed solution to portable off-grid energy production and distribution utilizing renewable energy sources. The goal is to highlight problems within the area of focus and present a potential solution to one, or multiple, of these problems. The presented solution shall be based on a solid engineering foundation and meet the technical requirements developed from needs that arise during the project. Methods. The work presented in this thesis was conducted with the use of DRM, Design Research Methodology, as the choice of research methodology while Design thinking was the choice of design approach. The use of DRM allowed for a structured and efficient research process that allowed for the possibility to validate result. The use of Design thinking as design approach provided methods and tools to support innovation while working with problems that were initially unknown or vaguely defined. Results. The result of the work presented in this thesis provides information regarding multiple problems and critical aspects within the area of focus. A list of requirements for a sustainable energy system to satisfy in order to enter the market is presented, where portability, reliability and redundancy are marked as key requirements. A proposed solution in the form of a portable modular sustainable energy production trailer utilizing different renewable energy sources was developed to allow for off-grid electricity generation. This combined with an energy distribution solution in the form of a energy storage module mounted on the Volvo TA15 system allows for autonomous energy transportation to the location of the energy need.  Conclusions. As the need for sustainable energy constantly increases, development of sustainable energy production and distribution systems that can operate off-grid has proven to be critical. The utilization of renewable energy sources has also been identified as a critical factor in parallel with the phasing out of fossil fuels. The proposed solution has provided evidence of the potential for a portable off-grid hybrid energy system and its potential impact on the global 2030-agenda goals for sustainability.
28

Small-scale wave motion energy generator : Technical &amp; Business parallel development

Quintana, Julio January 2015 (has links)
This MSc thesis was a project performed in a start-up that develops sustainable devices to exploit renewable energies, specifically in the field of energy harvesting in small scale. The objective of the thesis is to demonstrate the importance of developing the technical side of a project together with the development of the market. The idea is to enhance the success possibilities and work to get to the market as fast as possible with a minimum sellable product using the resources as efficiently as possible. The market analysis was the first step to be performed to understand what the start-up was getting into, at the beginning it was clear that the generator should be targeted to power remote applications that require small amounts of energy and a market that is not suitable for present technologies such as solar PV or micro wind turbines. After this a series of potential markets were identified in order to limit the research and three opportunities were selected. The buoy market was chosen, it has several sub-markets and the AtoN buoys, Fishing buoys and Meteorological buoys were considered the most important and suitable ones. Once the market was defined, the needs of the clients and users were discovered through research in the form of interviews and bibliographical research. Later on an experimental rig was used to test several models of the prototype under different parameters to select one that was close to what was demanded and that can actually be built. This approach was useful to dedicate resources efficiently, specially time and money. The last part of the thesis was to propose a sustainable business model describing a go-to-market strategy that considered both the limitations of the technology and the testing performed in the scope of this project and the expectations of the market for the proposed product. The methodology was a mixed use of business tools learned in the courses and the experiences of the people who were close to the start-up. There is a final reflection at the conclusions that describe the day-to-day of the start-up and the experiences learned as well as the recommendations for future work.
29

Experimental Demonstration of Agrivoltaic Systems via Multi-Scale Design and Characterization

Elizabeth Kathleen Grubbs (12232037) 20 April 2022 (has links)
As the global population approaches 11 billion people, demands for sustainable food, energy, and water (FEW) are approaching unprecedented levels. Current technology places sustainable FEW production methods in direct competition with one another for global surface area, such as land area for agriculture versus photovoltaic farms. This is because current installation methods for solar modules create deep shading that suppresses plant growth. The field of agrivoltaics (AgPV) addresses this issue directly by optimizing coproduction strategies for FEW and developing systems where competition is reduced; however, previous work has seen reductions in agricultural output. AgPV, where module architecture is also modified and agricultural output is minimally impacted, requires novel multi-level experimental design and characterization. In my proposed thesis, I will address the following two aspects of the project: (1) a farm-level experimental analysis of existing PV and (2) a device-level analysis of new and emerging PV material candidates. To establish the plausibility of this work, I designed and implemented an agrivoltaic system with two treatments that was successfully farmed this year. In my thesis, I will demonstrate a fully characterized utility scale AgPV array through several steps. First, I will validate the prior simulation work on the constructed AgPV array. Then I will experimentally correlate crop growth underneath the AgPV experiment. Next, the effects of the shadowing from the array on crop growth will be quantified. I will optimize the tracking algorithm for the array to maximize crop growth during the summer and power production during other seasons. Finally, I will investigate a platform for evaluation of novel PV materials and devices tailored for AgPV systems using Photoluminescence Excitation Spectroscopy (PLE) where I redesigned, constructed, and validated a new experimental design.
30

3D multimodality solar harvesting and energy generation system

Lyu, Mengyao 02 June 2023 (has links)
No description available.

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