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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.
1

Energy efficiency in the iron and steel industry : cases of Zimbabwe and South Africa

Muguti, Elizabeth Zivai January 2004 (has links)
Includes bibliographical references. / This study looks at possible improvements of energy efficiency in the iron and steel industry in Zimbabwe and the case of South Africa is studied also for comparison. Data required was obtained through field visits and international databases. The fieldwork findings, analysis and published literature contributed to the conclusions and recommendations. There is a relationship between technology advancement, energy efficiency and energy intensity. The more modern technology a country's steel industry adopts the more energy efficient it becomes and so lowers its energy intensity. Countries such as South Korea, Japan and Germany have adopted modern technologies and they are among the most efficient steel producers and have the lowest energy intensities while India and China have low levels of modern technologies, low efficiencies and high intensities. ZISCO, the iron and steel industry of Zimbabwe has a relatively high energy intensity (closer to China and India) compared to South Africa and other developing country producers. ZISCO has both new and old technology while industry in South Africa, which has retired most old technology and closed all its less efficient plants, is largely using new and even state of the art technology in some of its plants. In Zimbabwe the national economic and industrial policies have had negative impacts on the growth and development of its iron and steel industry. ZISCO needs policies that support the adoption of energy efficient technology, create a level playing field for downstream steel industries since ZISCO has the potential to influence growth of this sector and the sector has prospects for significant foreign currency earnings. The study recommends a restructuring of ZISCO to improve productivity, and energy efficiency through replacement of old technologies in the medium to long term and implementation of some identified less capital-intensive options that are typical in an integrated steel mill.
2

Potential contribution of solar thermal power to electricity supply in Northern Nigeria

Ogunmodimu, Olumide Oluwaseun January 2012 (has links)
Energy is an essential requirement for a reasonable socio economic development in a country; however, its provision depends on availability of energy sources and the require d investment. Nigeria possesses abundant deposits of energy sources ranging from fossil fuel to renewable energy sources. Over the years, the level of production of energy from these sources has been considerably low. The present level of electricity supply is short of demand and the supply is not reliable. As the country is experiencing rapid growth in population, adequate energy provision is necessary for corresponding level of production and development. The need for sustainable and renewable sources of energy has emerged globally owing to environmental issues associated with the use of conventional fuel. In order to consider the possibility of harnessing the solar energy resource in northern Nigeria, this study explores the potential contribution of the adoption of Concentrated Solar Power (CSP) technology to the energy system in the far northern States of Nigeria. These States are chosen because the region lies within a high sunshine belt and thus having a daily average DNI of 6.2 KWh/m2 / day and an annual average of 2320 KWh/m2/yr. The annual average DNI in the region is a bit higher than that of the Andasol CSP plant in Spain which is 2090 KWh/m2/yr. The thesis seeks to uncover the potential for CSP in Nigeria, and determine when the cost of energy from CSP will become competitive with the cost of energy from conventional power. Using three possible economic growth scenarios (reference (7%), high (10%) and optimistic (13%) economic growth scenarios) to model future energy demand and supply from CSP and conventional gas plant. The results obtained show possible competition from potential CSP plant in Nigeria depending on the international and domestic gas market. However, continuous payment of blanket subsidy on the domestic price of natural gas in Nigeria will adversely affect potential investment in CSP market in Nigeria.
3

A software tool for the preliminary performance modelling of central receivers and associated power cycles

Smith, Lee January 2011 (has links)
A software tool for assisting in the preliminary performance modelling of central receiver solar thermal plants was developed using Matlab®. Scope was limited to the thermodynamic study of the power cycle and receiver. The receiver model was validated by comparing results to published data. The model was able to simulate billboard, C-cavity and cylindrical receivers within 1% in cases involving single-phase fluids and by at most 3% - 5% for water. Performance studies were conducted to demonstrate the usefulness of the model. Power cycle studies investigated the performance limits on non-reheated cycles as well as the effects of reheat and regenerative feedwater heating. The results showed expected trends of efficiency increasing with turbine inlet temperature and pressures. Also, efficiency was shown to increase asymptotically with number of feedwater heaters and reheat was shown to improve exhaust quality and efficiency. Billboard and cylindrical receivers were studied in detail using a number of heat transfer fluids, namely thermal oil, molten salt, molten sodium and water to compare the relative performance over a range of rated powers. Water and thermal oil were shown to be the best performing fluids for use in billboards and cylindrical receivers, respectively. Water and salt were shown to require the least area for use in billboards and cylindrical receivers, respectively. The effects of power cycle performance on receiver performance and size were investigated from which it was found that receiver efficiency increases marginally with power cycle efficiency but the required area is reduced significantly.
4

The elephant in the room: The rise and role of India in the climate change negotiations

Coetzee, Kim January 2016 (has links)
The climate change negotiations under the United Nations Framework Convention on Climate Change have been ongoing since the first conference of the parties in 1995. Twenty years on there has been little progress reducing greenhouse gas emissions, the climate regime is in a state of flux and the role of developing countries therein is changing. During this period the majority of the work on climate change from within the International Relations discipline has been framed in a neoliberal institutionalist or neorealist frame. Studies in the climate policy canon have been predominantly similarly located, albeit implicitly. In its focus on India this dissertation provides a bridge between the climate policy literature and the theoretically framed climate change policy studies in the International Relations literature. This dissertation employs the Critical International Relations theoretical framework of Robert Cox. His theory outlines a 'framework for action' that enables and constrains how states act, and how they conceive of their agency. This framework, or historical structure, is created by a particular configuration of the forces exerted by ideas, institutions, and material capabilities, which when aligned, create a hegemonic historical structure. In the climate negotiations, India has been a vocal proponent of the ideas of equity and common but differentiated responsibilities from the earliest days of the Convention. India's changing material circumstances and geo-political status in the past decade raised the question of its role in the regime in relation to its long-supported ideas. This is a qualitative case study using documentary evidence triangulated with interview data from a range of key Indian stakeholders. I found that in the transition from abstract principle to operational precept the intersubjective idea of addressing climate change did not transmute into an intersubjectively shared idea of differentiation. Furthermore, once the idea of differentiation was to be operationalised in the negotiations, its primacy, indeed its very "intersubjectiveness", was contested by the idea of symmetry of obligations and responsibility. The ongoing regime flux is the outcome of this contestation between ideas held collectively by groups, as no stabilising hegemonic historical structure has been created. India's emergence has been insufficient to reinstate differentiation as an intersubjectively held idea and it is thus unable to secure a hegemonic historical structure in favour of differentiation.
5

Porphyrin and BODIPY Derived Donor-Acceptor Multi-Modular Systems: Synthesis, and Excited State Energy and Electron Transfer Studies

Benitz, Alejandro Daniel 05 1900 (has links)
This dissertation demonstrates that it is possible to create a donor-acceptor system that can transform sunlight into electrons. By using site-directed synthesis, it was possible to create a novel trans-A2B2 porphyrin. In the pursuit of creating a supramolecular system, both the novel (TPA-BT)2ZnP and C60imidazole combined in solution such that the nitrogenous lone pair of C60 imidazole would coordinate axially to the zinc atom in the porphyrin. The conjugates' characterization utilized spectral, electrochemical, and computational techniques. Computational studies revealed in the optimized structure that the HOMO localized on the porphyrin and LUMO centered over the C60imidazole entity. Rehm-Weller calculations showed feasibility of singlet-electron transfer. Femtosecond transient absorption studies documented an efficient photoinduced charge separation in the conjugate. The subsequent work through steady-state and time-resolved transient absorption techniques that photoinduced electron transfer takes place between the synthesized phenylimidazole functionalized bisstyrylBODIPY (BDP(Im)2) and three selected zinc tetrapyrroles. This dyad consisted of BDP(Im)2 and either zinc tetratolylporphyrin (ZnP), zinc-tetra-t-butyl phthalocyanine (ZnPc), or zinc tetra-t-butyl naphthalocyanine (ZnNc) in a solution solvated by σ-dichlorobenzene (DCB). The three dyads (BDP(Im)2:ZnP, BDP(Im)2:ZnPc, and BDP(Im)2:ZnNc) were investigated by spectroscopic, computational, and electrochemical methods. The 1:1 complex of the dyads in optical absorption studies were approximately ~104 M-1 suggesting moderately stable binding. Spectral and electrochemical studies of the dyads used to generate energy level diagrams indicated that PET was thermodynamically unfavorable in BDP(Im)2:ZnP but favorable when the zinc tetrapyrrole is selectively excited dyads—as confirmed in femtosecond transient absorption studies. In the third work, two novel tetrads, consisting of charge stabilizing triphenylamine (TPA) to either bithiophene (BT) or terthiophene (TT) via a covalent linker that is attached to the meso-position of a BODIPY. This BODIPY was further extended by linking it to fulleropyrrolidine via a catechol linker to a modified BODIPY. Computational studies revealed the electronic structures of the tetrads, which rendered the HOMO to be on TPA-BT/TPA-TT moiety, while the HOMO-1 to be on the BODIPY entity and the LUMO to localized to the fulleropyrrolidine. Coupling the results with the electrochemistry, deduced that there is the formation of (TPA-TT).+-BODIPY-C60.- and (TPA-BT).+-BODIPY-C60.- as charge-separated states after the selective excitation of BODIPY in the tetrads. Femtosecond transient absorption studies were conducted in non-polar toluene and polar benzonitrile, and results affirmed photoinduced charge separation in the tetrads.
6

A Human Side Of The Smart Grid: Behavior-Based Energy Efficiency From Renters Using Real-Time Feedback And Competitive Performance-Based Incentives

Fredman, Daniel 01 January 2018 (has links)
Our energy system is rapidly transforming, partially due to advances in internet and communications technologies that leverage an unprecedented amount of data. Industry proponents of the so-called “smart grid” suggest these technologies facilitate deeper engagement with end-users of energy (utility customers) that can in turn drive behavior-based changes and accelerate a renewable energy transition. While there has been progress in understanding how these technologies change consumer behavior using, for example, real-time feedback, it’s unclear how specific segments (e.g., renters) respond to these interventions; it’s also unclear why feedback is, or is not, producing changes in energy consumption. The literature suggests that behavioral strategies (e.g. information feedback, competitions, incentives) coupled with technology may present a way for utilities and efficiency programs to create savings—expanding opportunities for those often underserved by traditional approaches, such as renters—yet this coupling is not well understood, neither broadly (for all end users) nor specifically (for renters). This dissertation builds upon that literature and explores a human side of the smart grid, using a field experiment in renter households to test the interacting effects of real-time energy feedback and a novel form of financial incentive, referred to here as a competitive performance-based incentive. The experiment had two phases: phase one tested the feedback against a control group; phase two tested feedback, the incentive, and a combined treatment, against a control group. Results of these interventions were measured with pre- and post-treatment surveys as well as observed electricity consumption data from each household’s smart meter. The results of this experiment are described in three papers. Paper one examines the interventions’ individual and combined effectiveness at motivating renters to reduce or shift timing of electricity consumption. Feedback alone produced a significant savings effect in phase one. In phase two, the effect of the feedback wore off; the incentive alone had no significant effect; and the group that received feedback and the incentive experienced a doubling of savings relative to the effect of feedback alone, as observed in phase one. Paper two uses pre- and post-intervention survey data to examine how individual perceptions of energy change as a result of the interventions. Perception of large energy-using appliances changed the most in households that received feedback, suggesting that better information may lead to more effective behavior changes. Paper three leverages the results of the first two components to evaluate the policy implications and impacts on demand side management for utilities, efficiency programs, and the potential for behavior-based energy efficiency programs. Advocates of the smart grid must recognize the technology alone cannot produce savings without better engagement of end-users. Utility rate designers must carefully consider how time-based rates alone may over-burden those without the enabling technology to understand the impact of their energy choices.
7

Exploring the possibility of the insurance industry as a solar water heater driver in South Africa

Kritzinger, Karin 03 1900 (has links)
Thesis (MPhil)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: South Africa is facing an energy crisis on two levels; the existing capacity to supply electricity is unable to support future growth in demand, and the electricity being produced comes mostly from coal-fired power stations with associated emission problems. The South African government has a target for renewable energy to service 23% of the country’s energy consumption by 2013. This could potentially be realised through achievement of another government target, the installation of one million Solar Water Heaters (SWHs). On a technical level, Solar Water Heaters (SWHs) represent a completely viable renewable energy alternative for South Africa. It is an established and proven technology which has the potential to have a big impact on the country’s electricity capacity problems. SWHs can be used in a variety of applications from industry to households. Most of the hot water in South African homes is heated by electric resistance heating in standard electric water heaters and there are no technical obstacles to replacing most of these with SWHs, thereby delivering a saving of up to 70% of the water heating energy bill. Water heating currently accounts for 40% of domestic electricity consumption within a residential sector that uses 20-30% of the national supply. At the macroscale, the roll out of SWH programmes is completely scalable. The benefits of SWH installation accrue to the consumer in the form of a financial saving in the long-term and to society in the form of reduced emissions. Awareness of the benefits is growing amongst the general public, commercial institutions and in government. Sales are starting to pick up due to, amongst other reasons, electricity price hikes and government subsidies for SWH installations offered through the national electricity supply company, Eskom. A national building regulation enforcing energy-efficient water heating in new buildings has been drafted and is expected to be in place by mid 2011. The rate of change from electric to solar water heaters remains disappointingly slow, however. The SWH industry in South Africa accounts for less than 10% of total hot water solutions sold. This study sought to establish the opportunities as well as possible barriers for the creation of SWH programmes within the insurance sector. Close to 50% of all standard electric water heaters installed in South Africa are procured and installed via the insurance industry due to the failure of units that have endured beyond the manufacturer’s guarantee period. This presents an opportunity for interventions that encourage policyholders to change to SWHs. Such interventions, if successful, would dramatically speed up the roll out of SWHs in South Africa. In addition the study sought to determine the barriers to the uptake of SWHs by policyholders in the case of the two insurance companies that currently have SWH programmes in operation. Data was collected through interviews with representatives in the insurance industry and a range of SWH industry stakeholders and consumers. The literature review focused on SWH policies and regulations and corporate and marketing theories. The material on transition in socio-technological systems proved especially useful in understanding the complex dynamics of the study topic. The conclusion drawn from the research is that the South African insurance industry has the capacity and opportunity to drive the penetration of SWH technology. The opportunity is, however not being exploited to anywhere near its potential. The entire system is geared towards providing a particular ‘business-as-usual’ solution. Analysis conducted in this study confirms that the system is in a “locked-in” state and extremely resistant to change. If the opportunity is to be acted on, to supplant the dominant technology for water heating installed by the insurance industry with what is currently a niche technology (SWHs), an external landscape shock is almost certainly needed. This shock to the system could be aided by interventions that target a change in the current system’s logic. The study provides some suggestions in this regard. / AFRIKAANSE OPSOMMING: Suid-Afrika staar ‘n energie krisis in die gesig. Aan die een kant is die bestaande elektrisiteitsvoorsiening nie genoeg om plek te maak vir die toekomstige vraag na elektrisiteit nie en aan die ander kant word meeste van Suid-Afrika se elektrisiteit opgewek deur steenkoolaangedrewe kragstasies met gevolglike probleme as gevolg van vrylating van kweekhuis-gasse. Die Suid-Afrikaanse regering het ‘n teiken vir hernubare energie om 23% op te maak van die land se totale energie verbruik teen 2013. Hierdie teiken sou potensieel bereik kon word deur die bereiking van ‘n ander van die land se teikens, naamlik die instalering van een miljoen sonverhitters. Op ‘n tegniese vlak verteenwoordig sonverhitters ‘n lewensvatbare hernubare energie alternatief vir Suid-Afrika. Dit is ‘n beproefde tegnologie wat die potensiaal het om ‘n groot impak te hê op die elektrisiteit kapasiteitsprobleme van die land. Sonverhitters kan ‘n verskeidenheid van warm water behoeftes bevredig, van groot industrieë tot tuisverbruik. Meeste warm water in Suid-Afrikaanse huise word verhit deur standaard elektriese geisers. Daar bestaan geen tegniese hindernisse om hierdie geisers deur sonverhitters te vervang en tot 70% van die water verhittings energie rekening te bespaar nie. Water verhitting maak tans 40% van die totale huishoudelike elektrisiteits verbruik op. Die huishoudelike verbruik is 20-30% van die nasionale verbruik en selfs hoer gedurende piek. Op die makro skaal is die uitrol van sonverhitters heeltemal skaleerbaar. Die voordele van die installering van sonverhitters val die verbruiker toe in die vorm van finansiele besparing oor die lang termyn en vir die samelewing as geheel in die vorm van emissie besparings. Bewustheid van die voordele is aan die groei by die algemene publiek, kommersiele instansies en by die regering. Verkope het begin optel as gevolg van onder andere die elektrisiteits prysverhoging en die staatssubsidies vir sonverhitters aangebied via die nasionale elektrisiteits toevoer maatskappy, Eskom. A nasionale bouregulasie wat enegie doeltreffende waterverhitting sal afdwing op nuwe geboue is reeds opgestel en dit word verwag dat hierdie regulasie in plek sal wees teen middel 2011. Die koers van verandering van elektriese water verhitters na sonkrag bly egter teleurstellend laag. Die sonverhittings industrie in Suid-Afrika maak minder as 10% van die totale water verhittings mark uit. Hierdie studie het beoog om die geleenthede sowel as die moontlike versperrings tot die skepping van sonverhittings programme in die versekerings bedryf uit te wys. Die versekerings bedryf koop en installeer ongeveeer 50% van alle standaard elektriese geisers in Suid-Afrika as gevolg van elektriese geisers wat breek na die vervaardiger se waarborg verval het . As gevolg hiervan bestaan daar ‘n geleentheid vir intervensies wat polishouers aanmoedig om te verander na sonverhitters. Sulke intervensies, indien suksesvol, het die potensiaal om die uitrol van sonverhitters in die land dramaties te versnel. Verder het hierdie studie beoog om die versperrings tot die opname van sonverhitters uit te wys by twee versekerings maatskappye in Suid-Afrika wat wel sonverhittings programme het. Data is versamel deur onderhoude met verteenwoordigers van die versekeringsbedryf en ‘n reeks sonverhitting industrie belanghebbendes en verbruikers. Die literatuurstudie het gefokus op sonverhittings beleid en regulasies en korporatiese en bemarkings teorie. ‘n Literatuurstudie in oorgang in sosio-tegnologiese sisteme was veral nuttig om die komplekse dinamika van die sisteem te verstaan. Die gevolgtrekking van hierdie studie is dat die Suid-Afrikaanse versekeringsbedryf wel die kapasiteit en geleentleid het om die penetrasie van sonverhittings tegnologie te dryf. Hierdie geleentheid word egter nie gebruik tot sy volle potensiaal nie. Die ganse sisteem is gerat om ‘n spesifieke tegnologie op ‘n sekere manier te verskaf. Analise in hierdie studie bevestig dat die sisteem in ‘n geslote staat is en daar is uiterste teenkanting tot verandering. Indien hierdie geleentheid om die dominate tegnologie vir waterverhitting geinstaleer deur die versekerings bedryf te verplaas met wat op die oomblik nog ‘n niche tegnologie is (sonverhitters), is ‘n eksterne landskap skok nodig. Hierdie skok tot die sisteem kan aangehelp word deur intervensies wat ‘n verandering in die huidige sisteem logika teiken. Hierdie studie bied ‘n paar voorstelle in hierdie verband.
8

Unruly energies : provocations of renewable energy development in a northern German village

Carlson, Jennifer D. 23 October 2014 (has links)
This dissertation asks how inhabitants of a sustainable village are living out Germany’s transition from nuclear to renewable energy. The sustainable village remains a locus of optimistic attachments for renewable energy advocates, who argue that a decentralized power grid will enable people to more directly participate in power production and politics as “energy citizens.” Yet while rural areas have become sites of speculation, innovation and growth, few rural-dwellers are enfranchised in (or profiting from) the technoscientific projects in their midst. I draw upon 13 months of fieldwork in a northern German village transformed by wind turbines, photovoltaics and biofuels to consider why, asking what kinds of public life flourish in the absence of democratic engagement with renewable technologies. This ethnography engages the village as multiply constituted across domains of everyday life, including transit, farming, waste management, domestic life, and social gatherings. I found that environmental policy, everyday practices, and the area’s material histories combined to produce ontologies—senses of what exists—that circumscribe citizen participation in the energy sector, affording more formal opportunities to men than to women, and privileging farmers’ interests in plans that impacted the larger community. These findings illuminate how many villagers become ambivalent toward the project of the energy transition and disenfranchised from its implementation. Yet many who were excluded from formal participation also engaged with renewable technologies as they sensed out their worlds, using tropes of sustainable energy and technoscientific materials to place themselves in this emerging energy polity. Their everyday worldmaking brimmed with what I call unruly energies, structures of feeling that registered more as affects than as discourse. In the village, these took form as sensory disturbances, disquiet among neighbors, technoscientific optimism and skepticism toward environmental policy. These affective modes of attention, investment and participation were vital aspects of public life that shaped the transition’s unfolding. They exceeded liberal models of renewable energy citizenship, which presume that socioeconomic interest and environmental commitment are universal among citizens. In this way, unruly energies compel more nuanced attention to the multiple, contingent, site-specific ways in which citizenship takes form in the making of eco-capitalist energy infrastructure. / text

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