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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.
231

Solel till Akademiska sjukhuset : möjlig genererad effekt och solcellers estetiska konsekvenser

Enquist, Sofia January 2012 (has links)
Today many buildings and it´s nearby surroundings are designed to achieve some kind of environmental goal.The issue concerning energy consumption is currently at focus and it is relevant that we start increase the share of renewable energy. Solar energy is an infinite resource and should therefore be considered when selecting an energy supplier.   Uppsala University hospital is facing major restructuring when parts of the existing buildings will be refurbished and a large new building will be constructed. White Architects have developed a study concerning the new building and for some of the existing buildings on the hospital campus. Uppsala County requires tough energy measures and wants the new building to be classified as an eco-building in Whites following work. The classifications will involve high energy source requirements.   This work has been conducted to see if solar power can be envisaged as a supplementary energy source for the University hospital and also to investigate the aesthetic impact of solar cells on the new building. In this report, solar cells integrated on the facade and PV modules on the roofs have been studied. Focus has been to evaluate the potential of what each option can produce and what opportunity they have to become an intrinsic part of the architecture   The type of solar cell module, which in this case study has been proven to generate most electricity is stand-alone modules on roofs. These are however, more difficult to reconcile with the architecture. Solar cells on the facades should therefore still be considered as an alternative application.The result shows that the potential energy that can be generated by solar panels on the new building is large but not in relation to hospital´s electricity use. It is for that reason questionable whether solar installation, applied on the new building, can be seen as a good additional source of energy or if it will more become a matter of public relations.
232

Householders’ Perspective on Photovoltaic Application in Thailand

Pokapanich, Kantamala January 2011 (has links)
This study aims to explore householders’ perspective on photovoltaic application in Thailand using surveys which are distributed in a study area, Khon Kaen. The target groups are residents older than 15 years old who live in an urbanized area. There were no limitations for gender, level of income or education and living region in the study area. The purpose of this is to obtain different perspectives from different groups of people. The questions in the survey are designed to find out if solar home system interests those surveyed and what reasons they have to support their decision. The results show that 1) most of the householders are interested in adopting this technology and said ‘yes’, mainly because of environmental advantages although there are some barriers that block their access to this technology 2) some of them are considering it and answered ‘maybe’ but would change their answer to ‘yes’ if the technology would improve according to their conditions 3) few of them said ‘no’ and indicated financial reasons as the main barrier. When relating respondents’ answers to environmental awareness, it is shown that all of them provide a similar definition of ‘environment’. They also rate themselves quite high when it comes to environmental awareness. However, their answers about the solar home system depend on other issues that, in their perception, are more important than the environment.
233

Some Aspects of Microgrid Planning and Optimal Distribution Operation in the Presence of Electric Vehicles

Hafez, Omar 20 December 2011 (has links)
Increase in energy demand is one of the major challenges that utilities are faced with, thus resulting in an increase in environmental pollution and global warming. The transport sector has a significant share of the energy demand and is a major contribution of emissions to the environment. In Canada, almost 35% of the total energy demand is from the transport sector and it is the second largest source of greenhouse gas (GHG) emissions. The government of Ontario has aimed to move toward a green energy economy, thus resulting in increased penetration of renewable energy sources as well as Plug-in hybrid electric vehicle (PHEV) technology. Penetration of renewable energy sources into microgrids are gradually being recognized as important alternatives in supply side planning. This thesis focuses on the optimal design, planning, sizing and operation of a hybrid, renewable energy based microgrid with the goal of minimizing the lifecycle cost, while taking into account environmental emissions. Four different configurations including a diesel-only, a fully renewable-based, a diesel-renewable mixed, and an external-grid connected microgrid are designed, to compare and evaluate their economics, operational performance and environmental emissions. Analysis is also carried out to determine the break-even economics for a grid-connected microgrid. The well-known energy modeling software for hybrid renewable energy systems, HOMER, is used in the studies reported in this thesis. An optimal power flow (OPF) based optimization framework considering two different objectives, minimizing feeder losses and PHEV charging cost, are presented to understand the impact of PHEV charging on distribution networks. Three different charging periods are considered and the impact of the Ontario Time-of-Use (TOU) tariff on PHEV charging schedules is examined. The impact of PHEV charging on distribution systems in the presence of renewable energy sources is discussed by extending the developed OPF based model to include the contribution of renewable energy sources. The proposed model is evaluated under a variety of scenarios.
234

Sustainable Entrepreneurship : The Motivations and Challenges of Sustainable Entrepreneurs in the Renewable Energy Industry / Sustainable Entrepreneurship : The Motivations & Challenges of Sustainable Entrepreneurs in the Renewable Energy IndustryMaster

Bell, James, Stellingwerf, Jelmer January 2012 (has links)
Sustainability and sustainable development is slowly gathering momentum in public discourse, and greater attention and reverence in academic research. While there still appears to be no consensus defining sustainability, which has lead to hampered discussion, this should not impede nor hinder a greater call for dialogue of how to ultimately change the world, and for the global economy to consider what type of individual will address environmental and social issues simultaneously. We consider ‘traditional’ entrepreneurship still necessary and vital to the continuing development of disruptive innovation and market change, however, a new breed of entrepreneur must now achieve greater focus. A sustainable shift in societies development is required to guarantee a capacity to endure. Sustainable development is critical to not only the environments long-term well-being, but also a necessity to curve the ultimate slow demise of the human race. Economic responsibly toward the environment and society is imperative. Sustainable development meets at the confluence of three constituent parts - environmental sustainability, economic sustainability and socio-political sustainability, the foundations to an emerging new field of entrepreneurship - Sustainable Entrepreneurship.Sustainable Entrepreneurs enact a holistic approach to a venture start-up that embeds environmental, economic and social sustainability dimensions. Sustainable Entrepreneurs have received insufficient attention by the media, policy makers and have failed to grab the attention of academics to test theory in an exploratory cross-case analysis approach. Previous research has mainly been conceptual and theoretical. Literature is lacking practical insights into how entrepreneurs conduct sustainable entrepreneurial initiatives and whether such definitions hold true. A cross-case analysis of five entrepreneurs operating in the renewable energy industry is conducted, evaluating theory against real life. We fill this gap by conducting exploratory research in Sustainable Entrepreneurship, identifying the entrepreneurs motivations to start-up their unique venture, challenges faced throughout the venture development process and their impact within their defined market. It is evident throughout the five case studies all our entrepreneurs have encountered some sort of antecedent exposure to an environmental concern; leading to our belief that prior exposure to a sustainability related market failure has resulted in these entrepreneurs to pursue their business initiative. Leading from this analysis, it is evident Sustainable Entrepreneurs are highly motivated to solve environmental and/ or social related problems (sustainability-related market failures). Customer perceptions and unawareness for alternative sustainable products remain a considerable challenge. It is proposed that patents, cooperating with educational institutions, establishment of an international network and organisational culture, are all important practices that assist in the business development.
235

Embedded Multilevel Converter Design of a Slotless Tubular Linear Generator for Direct Renewable Energy Extraction

Chen, Chiao-Ru 15 August 2012 (has links)
The objective of this thesis is to design a multilevel converter circuit for driving slotless tubular linear generators (STLG) on retrieving renewable energy application. With the changing speeds and reciprocating directions of the movers, the electric energy generated from the STLG will exhibit large fluctuations and is hard to be used directly. Based on machine modeling and mover reference frame projection, a converter circuit and a data acquisition (DAQ)-based drive control scheme have been developed. From the experimental results, the control scheme implemented on the converter circuit can provide acceptable multilevel dc outputs at various operating modes.
236

Multi-port DC-DC Power Converter for Renewable Energy Application

Chou, Hung-Ming 16 January 2010 (has links)
In recent years, there has been lots of emphasis put on the development of renewable energy. While considerable improvement on renewable energy has been made, there are some inherent limitations for these renewable energies. For example, for solar and wind power, there is an intermittent nature. For the fuel cell, the dynamics of electro-chemical reaction is quite slow compared to the electric load. This will not be acceptable for modern electric application, which requires constant voltage of constant frequency. This work proposed and evaluated a new power circuit that can deal with the problem of the intermittent nature and slow response of the renewable energy. The proposed circuit integrates different renewable energy sources as well as energy storage. By integrating renewable energy sources with statistical tendency to compensate each other, the effect of the intermittent nature can be greatly reduced. This integration will increase the reliability and utilization of the overall system. Moreover, the integration of energy storage solves the problem of the slow response of renewable energy. It can provide the extra energy required by load or absorb the excessive energy provided by the energy sources, greatly improving the dynamics of overall system. To better understand the proposed circuit, "Dual Active Bridge" and "Triple Active Bridge" were reviewed first. The operation principles and the modeling were presented. Analysis and design of the overall system were discussed. Controller design and stability issues were investigated. Furthermore, the function of the central controller was explained. In the end, different simulations were made and discussed. Results from the simulations showed that the proposed multi-port DC-DC power converter had satisfactory performance under different scenarios encountered in practical renewable energy application. The proposed circuit is an effective solution to the problem due to the intermittent nature and slow response of the renewable energy.
237

PSCAD/EMTDC-Based Modeling and Analysis of a Microgrid with Renewable Energy Sources

Chu, Zhengguo 2010 May 1900 (has links)
Microgrid is a relatively new concept which has gained significant attention recently due to the increasing penetration of distributed energy sources. It brings many benefits to the traditional distribution system. Couples of microgrid testbeds in the forms of either hardware facilities or software simulation systems have been developed to study microgrid issues in many institutes throughout the world. In the work presented in this thesis, a microgrid system model in PSCAD/EMTDC was developed. The proposed microgrid system includes fundamental power system component models, two renewable energy source models (wind and solar) and one energy storage source model. Different case studies were conducted. The results from the simulation case studies showed that the proposed microgrid system in PSCAD had satisfactory performance under different scenarios with renewable energy sources. The proposed microgrid system model can be used for further research on microgrid issues.
238

NOx reduction with the use of feedlot biomass as a reburn fuel

Goughnour, Paul Gordon 2006 August 1900 (has links)
Coal fired power plants produce NOx at unacceptable levels. In order to control these emissions without major modifications to the burners, additional fuel called reburn fuel is fired under rich conditions (10-30 % by heat) after the coal burners. Additional air called overfire air (about 20 % of total air) is injected in order to complete combustion. Typically reburn fuel is natural gas (NG). From previous research at TAMU, it was found that firing feedlot biomass (FB) as reburn fuel lowers the NOx emission at significant levels compared to NG. The present research was conducted to determine the optimum operating conditions for the reduction of NOx. Experiments were performed in a small scale 29.3 kW (100,000 BTU/hr) reactor using low ash partially composted FB (LA PC FB) with equivalence ratio ranging from 1 to 1.15. The results of these experiments show that NOx levels can be reduced by as much as 90% - 95 % when firing pure LA PC FB and results are almost independent of. The reburn fuel was injected with normal air and then vitiated air (12.5 % O2); further the angles of reburn injector were set normal to the main gas flow and at 45-degrees upward. For LA PC FB no significant changes were observed; but high ash PC FB revealed better reductions with 45-degrees injector and vitiated air. This new technology has the potential to reduce NOx emissions in coal fired boilers located near cattle feedlots and also relieves the cattle industry of the waste.
239

Reliability Analysis of Off-shore Marine Energy System Power Transmission Scheme

Li, Ming-Quan 10 July 2008 (has links)
Marine energy is a renewable source that has not been exploited widely. Fetching the off-shore marine energy requires a lot of investments, thus, maximizing the power delivered by the marine current system is important. Marine current power generation may be limited during certain periods due to weather situation and far distance power transmission that makes failure rate arise and repair time long. In this thesis, using marine current speed recorded at Taiwan coastline, we analyze the reliability and not-delivery energy indices of different off-shore power collection topologies and transmission system by using fault tree analysis and network reduction method. Model parameter uncertainty effects on the system reliability are studied and economic assessments of these configurations are also conducted.
240

Logistic modeling of a biomass utilization system

Patana-Anake, Maetee, Tan, Jinglu, January 2009 (has links)
The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on December 30, 2009). Thesis advisor: Dr. Jinglu Tan. Includes bibliographical references.

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