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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

Landscapes of power : the cultural and historical geographies of renewable energy in Britain since the 1870's

Gardner, Zoë January 2008 (has links)
This thesis considers historical applications of naturally renewing energy resources in Britain from the beginnings of public electricity supply in the late nineteenth century to the period immediately prior to the first State interest in such technology in the early 1980s when it became conceptualised as 'renewable'. After a comprehensive review of twentieth century engagements with renewable energy and the academic literatures pertaining to 'water, engineering and landscape' the thesis focuses on two distinct case studies. The first charts the technological, cultural and political evolution of hydro-electricity for public supply which developed over the course of the nineteenth century and was instituted from the 1870s. Detailed consideration of the Worcester hydroelectric station reveals that the development of hydro-electricity in the late nineteenth century symbolised a wider social and cultural demand for 'civic improvement’, and highlights the nature of water as a contested resource within late-Victorian civic arenas. The second traces the history of the Centre for Alternative Technology (CAT), a practical demonstration of alternative energy technologies established in rural mid-Wales during the early 1970s. In a discussion centred on 'alternativeness', the exploration of alternative energy technologies in the early 1970s was the preserve of an emerging counter-culture which sought to implement new visions of Environment and Society. Having revealed these hitherto dormant histories, the thesis concludes with a comparative discussion of the two case studies reflecting on these respective renewable energy projects and their uses as instruments of ‘modernisation' and attempts to extract the significance of these histories in the context of current discourses of renewable energy.
22

The characteristics and perception of small wind system noise

Taylor, Jennifer M. January 2012 (has links)
The UK has committed to sourcing 15% of its energy from renewable sources by 2020 and wind turbines have the potential to contribute towards this target. Due to the Feed-In-Tariffs introduced by the UK Government in 2010, the potential uptake of micro-generation methods such as small wind is likely to increase. However, many barriers exist which prevent widespread implementation, such as noise concerns. There is little work available in the open literature quantifying the problem because much of the existing research focuses on large scale turbines. The need for an increase in interdisciplinary research in this area has also been called for. This research fills the gap in the literature by seeking to better understand the noise levels generated by small wind systems, the characteristics of the noise and people’s reactions to this noise. The research is interdisciplinary, incorporating engineering, to measure, characterise and model the noise from small wind systems and psychology, to identify the type of people who are most likely to perceive the noise. Environmental noise measurements have been taken at small wind system installations to quantify and characterise the noise levels. This work included an assessment of the attenuation of the noise. Studies have been carried out on individuals living close to small wind system installations, as well as individuals being played recordings of wind turbine noise to investigate the level and type of noise they perceive and to link this to an individual’s attitude towards wind turbines, personality traits and symptom reporting. CFD has been used to model the flow fields around 2D blade sections to identify the likely noise mechanisms associated with small wind systems by observing the turbulent regions near the aerofoil wall. Finally, a comparison of the three methods has been carried out to identify that the overall level of small wind system noise is low but it is the nature of the sounds that increase the likely perception of the noise.
23

The Influence of Molecular Transport on the Structure-Property Relationships of Amphiphilic Block Copolymer Membranes

Unknown Date (has links)
Polymers are essential to modern life. Yet there still remains a wealth of knowledge to discover regarding novel polymeric materials, processing techniques, and applications. The synthesis and application of nanostructured amphiphilic block copolymers have attracted significant interests in the last decade. Depending on the structure, composition, and architecture; a wide range of applications have been reported in various fields of research. The need to accurately access the fundamental structure-property relationships in polymers are of paramount importance to the performance in various applications. Some of these applications include the use of polymer membranes for CO2 capture from flue gas, for water purification and wastewater treatment, as well as polymer electrolytes for lithium batteries. This dissertation therefore, focuses on contributing fundamental knowledge on the structure-property relationships of amphiphilic block copolymer membranes to improve its performance. With the use of poly(styrene–block–ethylene oxide), (SEO) and high molecular weight poly(ethylene oxide) membranes and polystyrenes of various molecular weight and tacticity, experimental work has been conducted with relevant consideration in the aforementioned application areas. The fundamental study of the effects of molecular transport (e.g. water vapor) in an amphiphilic block copolymer membrane consisting of hydrophilic blocks of poly(ethylene oxide) and hydrophobic blocks of polystyrene (PS-b-PEO) was investigated. The influence of water solubility and diffusivity on the block copolymer morphology were examined at various temperatures and water concentrations. A comprehensive study conducted using Fourier-transform infrared spectroscopy (FTIR) to investigate the effect of water activity on PEO crystallinity, and how the PEO crystallinity in turn affects water sorption and diffusion was investigated. Also, isothermal vapor-sorption equilibria and diffusion coefficients of water in different architectures of block copolymer membranes will be discussed. This fundamental study is important for applications that rely on PEO-containing materials, as PEO crystallite melting dramatically impacts transport and mechanical properties. For lithium battery application, the study of ion association effects and the ion-polymer interactions in high molecular weight poly(styrene–ethylene oxide) block copolymer (SEO) and complexes with lithium bis(trifluoromethane sulfonyl) imide salt (LiTFSI) as polymer electrolyte using FTIR-ATR spectroscopy were conducted. The dissolution of the lithium salt in the PEO phase as it influences the structure of the ion conducting phase of the polymer (PEO) was investigated. The infrared bands observed in the polymer–salt complexes as a function of salt concentration and temperature show different solvation and degree of ion association behavior. An understanding of the relationship between ionic conductivity and degree of solvation of lithium salts as a function of ion concentration was explained from the FTIR-ATR results. Also, Structural and stress relaxations have been measured with x-ray photon correlation spectroscopy (XPCS) and rheology, respectively, as a function of salt concentration and temperature. Results from XPCS experiments showed hyperdiffusive motion for various lithium salt concentrations and at varying temperatures, which is indicative of soft glassy materials. This behavior is attributed to cooperative dynamics. The decay time was a weak, non-monotonic function of salt concentration and decreased with increasing temperature, in an Arrhenius fashion. In contrast, the shear modulus decreased with increasing salt concentration and increasing temperature. The entanglement relaxation from rheological measurements followed Vogel-Fulcher-Tammann behavior. The structural decay time was slower than the entanglement relaxation time at temperatures above the glass transition temperature, but they were approximately equal at Tg regardless of salt concentration. This may indicate a fundamental connection between cooperative structural motion and polymer chain motion in this material. / A Dissertation submitted to the Department of Chemical and Biomedical Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester 2017. / September 22, 2017. / Crystallite Dissolution, SEO electrolyte, SEO Structure, Stress relaxation, Structural relaxation, Water Transport / Includes bibliographical references. / Daniel T. Hallinan, Jr., Professor Directing Dissertation; William S. Oates, University Representative; John C. Telotte, Committee Member; Rufina G. Alamo, Committee Member; Hoyong Chung, Committee Member.
24

Investigation of innovative thermochemical energy storage processes and materials for building applications

Aydin, Devrim January 2016 (has links)
In this study, it is aimed to develop an innovative thermochemical energy storage system through material, reactor and process based investigations for building space heating applications. The developed system could be integrated with solar thermal collectors, photovoltaic panels or heat pumps to store any excess energy in the form of heat for later use. Thereby, it is proposed to address the problem of high operational costs and CO2 emissions released by currently used fossil fuel based heating systems in buildings. The aim of the study has been achieved by investigating and evaluating five of the following aspects: • Investigation of the feasibility of building integrated solar driven THS system under cold and mild climates, • Synthesis, characterization and physical experimentation of novel composite sorption energy storage materials • Development and investigation of a modular laboratory scale sorption reactor that use embedded air diffusers inside the sorbent for improving the energy storage density • Development and investigation of a full- scale modular solar driven THS system • Development and investigation of a heat pump driven sorption storage heater using multi-layer fixed bed sorption reactor These works have been assessed by means of computer simulation, laboratory and field experimental work and have been demonstrated adequately. The key findings from the study confirm the potential of the examined technology. Initially, a comprehensive review on thermal energy storage, with the aim of investigating the latest advancements on THS systems was performed. A comparative analysis on applicability of different heat storage methods for short term and seasonal heat storage under climate conditions in the UK, was also carried out. Results showed that short term heat storage is not a feasible option in the UK due to the very limited solar radiation. For the case of seasonal heat storage, it was found that, each 1 m3 of THS can provide averagely 14% of monthly (October to March) heating demand of a 106 m2 building, whereas LHS and SHS can provide 6% and 2% respectively. Later on, a range of candidate composite sorption materials were synthesized and characterized. Based on the applied characterization techniques, it was found that Vermicuilite-CaCl2 (SIM-3a) has excellent Ed coupled with good EMC and temc with its TGA analysis also suggesting significant mass loss in the working range 30 < T < 140 °C. Physical experimentation of the developed materials in a small scale custom test rig was also performed and in accordance with the characterization results, SIM-3a displayed the best hygrothermal and cyclic performance. These findings suggested that SIM-3a has very good potential for use in an open THS system. Upon completion of the material based studies, a 3kWh laboratory scale novel reactor using perforated pipes embedded inside the heat storage material was developed. The overall energy density of the reactor using SIM-3a was found 290 kWh/m3. Based on the obtained encouraging results, same concept was up scaled to a modular 25 kWh sorption pipe heat storage and similar energy density was achieved. Following the experimental work, theoretical analysis of the THS potential in Mediterranean climate conditions is conducted with a case study of the Island of Cyprus. The analysis results showed that the required heat storage volume to fully compensate heating demand of a domestic building in winter (December to February) is 5.25 m3 whilst the time required for charging the THS material with 8 m2 solar air collectors is slightly more than a month. The economic and environmental analyses results showed that payback period of the solar driven THS is 6 years whilst total CO2 emissions savings over 25 years lifetime is 47.9 tonnes. In order to validate the applicability of THS in Cyprus, a small prototype of integrated sorption pipe-solar concentrator was also developed and tested for room heating. It was found that adsorbent could be regenerated with solar energy during winter day time to be utilized at night for space heating. Study results also showed that sorption pipe with a heat storage volume of 0.017 m3 could meet up to 87% of the daily heat demand of a 12.4 m2 building. In order to validate the performance of the laboratory tested THS material and concept, a real scale (1000 kWh) modular solar driven THS system was developed based on the interpretation of the obtained theoretical, numerical and experimental data in earlier stages of the study. The preliminary testing on the prototype showed that each of four reactors could discharge a total of 248 kWh of thermal energy with an average thermal power of 4.8 kW. Additionally it is found that, in direct solar heating mode, transpired solar collectors used in the system could also generate daily total of 17 kWh thermal energy for the average solar intensity of 0.3 kW/m2. In the final stage of the study, a heat pump driven sorption storage heater was developed and investigated. The developed system performance was assessed with 5 different adsorption materials and under different operating conditions. The study results showed that Sim-3a and Vermiculite–(LiCl-CaCl2) (Sim-3cl) has the best hygrothermal performances and hygro-cyclic efficiencies. According to study results, COPs varies in the range of 1→2 depending on sorption materials properties and system operating conditions.
25

Leveraging Policy for Renewable Energy Development in Industrialized Countries and Emerging Markets

Tang, Amy January 2013 (has links)
Renewable energy has the ability to play a dominate role in addressing both rising energy demand and the need for sustainable growth. Various policy measures and incentives have aided its growth in both developed and developing countries. This dissertation analyzes existing policies and financial mechanisms used to encourage renewable energy development through three academic papers. I first propose the carbon revenue bond as a new financing tool to complement the environmental credit markets that exist in developed countries. Stochastic modeling techniques are used to simulate future credit prices and determine bond value. Use of the carbon revenue bond is illustrated through three examples of wind energy projects in the European, Australian and New Jersey markets. In the absence of mature markets in developing countries, I develop the strategic structure matrix as a new framework to explain the various effects of policy measures in order to better shape future policy design. By synthesizing previous literature on how organizations are able to affect the diffusion of a new technology, the strategic structure matrix is able to deepen understanding of how policy can influence renewable energy growth. The explanatory power of the framework is demonstrated through a case study on the different paces of wind power diffusion in five Indian states. Lastly, I evaluate the Clean Development Mechanism as a tool to encourage investment from developed nations for renewable infrastructure in developing countries. I create an agent-based model to simulate investment decisions under different improvements to the program, providing quantitative support for the effectiveness of some improvements over others. In addition to each paper's individual contributions, the findings collectively provide important implications for the future of renewable energy policy and its ability to support continued sustainable growth.
26

A distributed renewable energy system meeting 100% of electricity demand in Humboldt County : a feasibility study /

Ross, Darrell Adam. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 63-65). Also available via Humboldt Digital Scholar.
27

Ohio consumers' profiles, willingness to pay, and attitudes regarding anaerobic digestion on dairy farms

Sanders, Daniel J., January 2009 (has links)
Thesis (M.S.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 86-89).
28

Renewable liquid fuels from catalytic reforming of biomass-derived oxygenated hydrocarbons /

Barrett, Christopher J., January 2008 (has links)
Thesis (Ph.D.)-- University of Wisconsin--Madison, 2008. / Includes bibliographical references (p. 138-144). Also available on the Internet.
29

A literature study of renewable energy tax incentives

Nortje, Dola. January 2009 (has links)
Thesis (M.Com.(Taxation)) -- University of Pretoria, 2009. / Summary in English and Afrikaans. Includes bibliographical references.
30

An empirical assessment of entry into the green power market

Mester, Gretchen S. January 1900 (has links)
Thesis (Ph.D.)--University of Oregon, 2004. / Adviser: William T. Harbaugh. Includes bibliographical references.

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