ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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- All Subjects: Alternative Energy
Description
Portable devices rely on battery systems that contribute largely to the overall device form factor and delay portability due to recharging. Membraneless microfluidic fuel cells are considered as the next generation of portable power sources for their compatibility with higher energy density reactants. Microfluidic fuel cells are potentially cost effective and robust because they use low Reynolds number flow to maintain fuel and oxidant separation instead of ion exchange membranes. However, membraneless fuel cells suffer from poor efficiency due to poor mass transport and Ohmic losses. Current microfluidic fuel cell designs suffer from reactant cross-diffusion and thick boundary layers at the electrode surfaces, which result in a compromise between the cell's power output and fuel utilization. This dissertation presents novel flow field architectures aimed at alleviating the mass transport limitations. The first architecture provides a reactant interface where the reactant diffusive concentration gradients are aligned with the bulk flow, mitigating reactant mixing through diffusion and thus crossover. This cell also uses porous electro-catalysts to improve electrode mass transport which results in higher extraction of reactant energy. The second architecture uses porous electrodes and an inert conductive electrolyte stream between the reactants to enhance the interfacial electrical conductivity and maintain complete reactant separation. This design is stacked hydrodynamically and electrically, analogous to membrane based systems, providing increased reactant utilization and power. These fuel cell architectures decouple the fuel cell's power output from its fuel utilization. The fuel cells are tested over a wide range of conditions including variation of the loads, reactant concentrations, background electrolytes, flow rates, and fuel cell geometries. These experiments show that increasing the fuel cell power output is accomplished by increasing reactant flow rates, electrolyte conductivity, and ionic exchange areas, and by decreasing the spacing between the electrodes. The experimental and theoretical observations presented in this dissertation will aid in the future design and commercialization of a new portable power source, which has the desired attributes of high power output per weight and volume and instant rechargeability.
ContributorsSalloum, Kamil S (Author) / Posner, Jonathan D (Thesis advisor) / Adrian, Ronald (Committee member) / Christen, Jennifer (Committee member) / Phelan, Patrick (Committee member) / Chen, Kangping (Committee member) / Arizona State University (Publisher)
Created2010
Description
Solar energy is a disruptive technology within the electricity industry, and rooftop solar is particularly disruptive as it changes the relationship between the industry and its customers as the latter generate their own power, sell power to the grid, and reduce their dependence on the industry as the sole source provider of electric power. Hundreds of thousands of people in the western United States have made the decision to adopt residential rooftop solar photovoltaic technologies (solar PV) for their homes, with some areas of western cities now having 50% or more of homes with solar installed. This dissertation seeks to understand how rooftop solar energy is altering the fabric of urban life, drawing on three distinct lenses and a mixed suite of methods to examine how homeowners, electric utilities, financial lenders, regulators, solar installers, realtors, and professional trade organizations have responded to the opportunities and challenges presented by rooftop solar energy. First, using a novel solar installation data set, it systematically examines the temporal, geographic, and socio-economic dynamics of the adoption of rooftop solar technologies across the Phoenix metropolitan area over the decade of the 2010s. This study examines the broad social, economic, and urban environmental contexts within which solar adoption has occurred and how these have impacted differential rates of solar uptake. Second, using survey and real estate data from the Phoenix metropolitan area, it explores how solar energy has begun to shape important social and market dynamics, illuminating how decision-making in real estate transactions, including by buyers, sellers, agents, lenders, and appraisers is shifting to accommodate houses with installed solar systems. Lastly, the study explores patterns of rooftop solar adoption across major electric utilities and what those can tell us about the extent to which corporate social responsibility and sustainability reporting have affected the practices of investor-owned electric utilities (IOU) within the western US.
ContributorsO'Leary, Jason (Author) / Fisher, Erik (Thesis advisor) / Miller, Clark (Thesis advisor) / Dirks, Gary (Committee member) / Arizona State University (Publisher)
Created2021