Theses and Dissertations at Montana State University (MSU)
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Item Thermal energy storage with sensible heat in an air-alumina packed bed using axial flow, axial flow with layers and radial flow(Montana State University - Bozeman, College of Engineering, 2020) Al-Azawii, Mohammad Mahdie Saleh; Chairperson, Graduate Committee: Ryan Anderson; Carter Theade, Megan Danczyk, Erick Johnson and Ryan Anderson were co-authors of the article, 'Experimental study on cyclic behavior of thermal energy storage in an air-alumina packed bed' published in the journal 'Journal of energy storage' which is contained within this dissertation.; Carter Theade, Pablo Bueno and Ryan Anderson were co-authors of the article, 'Experimental study of layered thermal energy storage in an air-alumina packed bed using axial pipe injections' in the journal 'Applied energy' which is contained within this dissertation.; Duncan Jacobsen, Pablo Bueno and Ryan Anderson were co-authors of the article, 'Experimental study of thermal behavior during charging in thermal energy storage packed bed using radial pipe' in the journal 'Applied thermal engineering' which is contained within this dissertation.Thermal behavior in a packed bed thermal energy storage (TES) system is studied experimentally. TES systems are a promising solution to integrate renewable energy sources such as solar energy. The performance of such systems can be affected by different variables such as storage material size/type, pressure, temperature, heat transfer fluid (HTF), storage type (sensible/latent heat), and flow rate. Although these variables have been studied in literature, the resulting thermal dispersion and heat losses to the environment have been considered in few studies. This thesis studies the thermal behavior of an air-alumina TES packed bed focusing on dispersion and heat losses to quantify the thermal performance. Reducing their effects can improve the thermocline and thus thermal efficiency. The research efforts in this work quantify these effects and provide two new methods to reduce thermal dispersion and increase exergetic efficiency. Three configurations were considered in the present study. In the first configuration, a traditional packed bed is used focusing on performance for multiple partial cycles. This configuration quantified the thermal performance and served as a basis to compare the results from the other configurations. Dispersion effects were found to accumulate before a steady state was achieved during cycling. In the second and third configurations, novel pipe injection techniques were used to charge/discharge the bed. First, the normal bed is divided into layers via inserting pipes along the bed's axial length, focusing on a full charge-discharge cycle. Results show that exergy efficiency increases with flow rate and number of layers. The thermocline improved and dispersion losses decreased with number of layers. Second, a perforated pipe to facilitate radial flow was inserted at the center of the bed along the axial length to heat the bed. Radial charging shows higher charging efficiency compared to normal axial charging. Pipe injection is a novel method and a promising technique that improves the thermal performance of a lab scale storage bed, especially the layering method. Radial injection warrants more investigation to quantify its performance in thermal cycles.Item Aluminate spinels for use as catalyst enhancement of solid oxide fuel cells(Montana State University - Bozeman, College of Engineering, 2019) Zachariasen, Marley Sarria; Chairperson, Graduate Committee: Stephen W. SofieThe growing necessity to find clean, efficient power sources has led to the advancement of technology in various fields of renewable energy. The field of electrochemical energy conversion, better known has Hydrogen Fuel Cell energy, has shown promise in replacing fossil fuels. This technology is fuel flexible, emits no harmful products, and generates power at efficiencies double or triple that of the Carnot combustion cycle widely used in automotive propulsion and large scale combustion power generation. However, the power production is limited by the short life expectancy of the components used to convert the chemical energy of the fuel into an electrical current. Two mechanisms work simultaneously during fuel cell operation to degrade the anodic electrode of the cell. The coarsening of the catalyst metal particles reduces the total active area of the anode while contaminants from the fuel deposit on the anodes remaining active areas, blocking fuel from the locations where the reaction takes place. Recent studies have shown that doping the industry standard fuel cell anode, Ni/YSZ, with a compound known as Aluminum Titanate (ALT) increases the overall resiliency of the cell. When heat-treated, ALT disassociates in to aluminum and titanium oxides which are then able to go into solution with the material components of the anode. These new secondary phases were shown to increase the strength and overall power output of the cell while decreasing the rate at which the catalyst coarsens. The electrochemical enhancements were attributed to the aluminum based secondary phase, known as nickel aluminate, a spinel structured compound which undergoes unusual reduction and catalytic transport kinetics. This work assesses the viability of transferring these enhancement effects to various other cermet anode systems by individually exchanging the ceramic ion conductor and metal electrocatalyst. The electrochemical performance and degradation, as well as mechanical properties, were evaluated for Ni/GDC anodes doped with ALT and alumina. In addition, synthesis and reduction behavior of cobalt and copper aluminate spinels were analyzed for similarities with nickel aluminate.Item X-ray photoelectron diffraction analysis of the epitaxial growth of titanium on the (110) surface of aluminum(Montana State University - Bozeman, College of Letters & Science, 1996) Krasemann, VolkerItem Cake-o-rama(Montana State University - Bozeman, College of Arts & Architecture, 1990) Woloson, Wendy AdairUsing cakes as subject matter is a continuation of the food imagery I have drawn from in the past. Party cakes, especially, represent an excessive consumption at luxurious, festive gatherings. In a larger context, the cakes allude to a delirious atmosphere paralleling the vacant mentality promoted by the mass media in our culture. I direct this criticism through my work by creating the cakes with "flavors" - specific popular belief systems that "decorate" the cakes with satirical commentary. Thus, the super-saturated tiered cake with candle-crown and banner embodies the superficial idealization of a pageant queen. Because their hats are alike, the Pope and a Klansman share a cake in an uncomfortable stasis of competing ideologies. The decorative dome atop the Capitol transforms into a hovering U.F.O., suggesting a recent or imminent invasion. The humor in my work serves as an important vehicle for conveying more serious ideas. I question peoples' blind reliance on established beliefs and obsolescent attitudes. My scope ranges from ancient religious adoration to the deification of certain contemporary institutions. I have chosen to work with both prints and sculptures due to my eclectic technical background.