Browsing by Subject "Photovoltaic power generation"
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Item Adventures in main group chemistry: from molecules to materials(2008-05) Findlater, Michael; Cowley, Alan H.Three synthetic methods have been explored for the preparation of several novel boron-substituted amidinates and guanidinates. The extension of heterocumulene insertion chemistries to boron-aryl, boron-metallocene and boron-transition metal moieties has also been achieved and the mechanism of such insertions is addressed via density functional theory modeling techniques. The reactivity of these complexes is also explored, mainly through halide abstraction methodologies to generate boron cations, which are potent Lewis Acids and may be useful in promoting organic transformations or in the polymerization of ethylene. The synthesis and characterization of the elusive monomeric low valent carbenoid boron(I), a compound with a formal lone pair located upon the boron center, has been lacking. The suitability of the guanidinate ligand system to support such a species is also discussed and a combined experimental and theoretical approach to this highly topical problem is also presented. Thirdly, the use of photovoltaics (devices which convert solar energy directly into electricity) as an alternative source of energy outwith fossil fuel technologies is a rapidly growing area of interest. Initial efforts to use a novel approach, which incorporates inorganic nanocrystals wired into a conducting polymer matrix, are also presented. Successful synthetic approaches to the gallium, aluminum and indium monomeric precursors suitable for electropolymerization were developed. These compounds proved to be effective starting points for the generation of conducting polymers with embedded III/VI (Ga₂S₃) nanocrystals with further studies currently underway as to their III/V (InP, GaAs) compatriots. Finally, a retrospective of projects that may best be described in terms of the moniker "Loose Ends and Future Directions" will be presented. The aim of which will be to serve as a useful guidepost for further studies in the fields and topics discussed.Item Energy storage sizing for improved power supply availability during extreme events of a microgrid with renewable energy sources(2012-08) Song, Junseok; Kwasinski, Alexis; Grady, William M.; Driga, Mircea; Hallock, Gary; Son, Yoo SeokA new Markov chain based energy storage model to evaluate the power supply availability of microgrids with renewable energy generation for critical loads is proposed. Since critical loads require above-average availability to ensure reliable operation during extreme events, e.g., natural disasters, using renewable energy generation has been considered to diversify sources. However, the low availability and high variability of renewable energy sources bring a challenge in achieving the required availability for critical loads. Hence, adding energy storage systems to renewable energy generation becomes vital for ensuring the generation of enough power during natural disasters. Although adding energy storage systems would instantaneously increase power supply availability, there is another critical aspect that should be carefully considered; energy storage sizing to meet certain availability must be taken into account in order to avoid oversizing or undersizing capacity, which are two undesirable conditions leading to inadequate availability or increased system cost, respectively. This dissertation proposes to develop a power supply availability framework for renewable energy generation in a given location and to suggest the optimal size of energy storage for the required availability to power critical loads. In particular, a new Markov chain based energy storage model is presented in order to model energy states in energy storage system, which provides an understanding of the nature of charge and discharge rates for energy storage that affect the system's power output. Practical applications of the model are exemplified using electrical vehicles with photovoltaic roofs. Moreover, the minimal cut sets method is used to analyze the effects of microgrid architectures on availability characteristics of the microgrid power supply in the presence of renewable energy sources and energy storage. In addition, design considerations for energy storage power electronics interfaces and a comparison of various energy storage methods are also presented.Item Feasibility of photovoltaic cells on a fixed mirror distributed focus solar bowl(Texas Tech University, 1986-08) Calico, Steve EugeneThe object of the Crosbyton Solar Power Project was to design a solar-fossil hybrid power plant to provide electrical power to Crosbyton, Texas. To meet this objective a test facility was built south of town. The power is produced by focusing sunlight to convert water to steam then using the steam to turn a generator to produce electricity. In times of inclement weather, darkness, or breakdown, electricity is provided by conventional fossil fuels. With the advances in photovoltaic cell efficiency and decreases in cost of manufacturing, direct conversion from solar energy to electrical energy could be possible. The purpose of this study is to determine the technical feasibility of solar cells on a fixed mirror distributed focus solar bowl, such as at the test facility at Crosbyton. Most of the research effort was devoted to the design of the receiver. The cells are mounted on the movable receiver, which tracks the sun during the day. The receiver with attached photovoltaic cells is the critical design element in this solar-electric concept. Its shape and size impact the solar concentration on the cells and the cooling requirements. Once the receiver was designed the essential support equipment needed was studied. These support systems provide for the cooling of the cells and conditioning the direct current electrical output from the solar array to be compatible with the load requirements. No estimate of the cost of construction and operation of such a solar system was made. Such an estimate would be needed to determine the overall feasibility of such a system. However, the simplicity of the receiver designed here and the projections of low cost commercially available solar cells indicate that the feasibility of direct energy conversion by solar cells on a distributed focus receiver may become practical in the near future.