Master of Sciences, Case Western Reserve University, 2022, Physics

The increasing adoption of renewable sources of electricity (i.e. wind and solar farms) is being driven by the demand for carbon neutral electricity production. Although zero carbon is emitted during electricity production, these renewable energy sources suffer from intermittency, which is a mismatch between the supply and demand of electricity of the grid. Renewable energy sources, such as wind and solar, produce their peak electricity at off-demand periods of the day. This strains the electrical grid as it risks over-generation in some locations as well as a need for quick ramping of the electrical load which is hard on electricity producing infrastructure. As a partial solution to intermittency, pumped storage hydropower (PSH) is the dominant form of grid-scale energy storage. PSH accounts for 95% of the U.S. grid-scale storage capacity, which amounts to 22.9 GW of capacity [1]. The EIA also estimates with all possible sites, the U.S. can double their PSH capacity [1]. However, much more than that is not feasible being constrained by the availability of locations suitable for PSH. As a result, other gridscale energy storage options are in development. The main options include batteries, thermal energy storage, compressed air energy storage (CAES) and flywheels. However, these storage options are plagued by high cost per kWh prices, location specificity (ex. PSH, CAES) and/or low energy density. With these concerns in mind, Cratus LLC is developing a molten salt thermal energy storage option known as ThermaBlox, which is location-independent, low-cost, and high-capacity (with the capability to scale). ThermaBlox will play a significant role in intermittency reduction while enabling increased adoption rates of renewable energy.

Committee: Edward Caner (Committee Chair); Dr. Benjamin Monreal (Committee Member); Dr. Robert Brown (Committee Member) Subjects: Chemical Engineering; Energy; Engineering; Entrepreneurship; Fluid Dynamics; Mathematics; Nanotechnology; Physics; Technology

Master of Science in Renewable and Clean Energy Engineering (MSRCE), Wright State University, 2023, Renewable and Clean Energy

In the past several years, the energy sector has experienced a rapid increase in renewable energy installations due to declining capital costs for wind turbines, solar panels, and batteries. Wind and solar electricity generation are intermittent in nature which must be considered in an economic analysis if a fair comparison is to be made between electricity supplied from renewables and electricity purchased from the grid. Energy storage reduces curtailment of wind and solar and minimizes electricity purchases from the grid by storing excess electricity and deploying the energy at times when demand exceeds the renewable energy supply. The objective of this work is to study the generation of electric power with wind turbines and solar panels coupled to either battery energy storage or hydrogen energy storage. So that logical conclusions can be drawn on the economic effectiveness of battery and hydrogen energy storage, four scenarios are analyzed: 1) purchasing all required electricity from the grid, 2) generating electricity with a combined wind and solar farm without energy storage, 3) generating electricity with a combined wind and solar farm with battery energy storage, and 4) generating electricity with a combined wind and solar farm with hydrogen energy storage. All four of these scenarios purchase electricity from the grid to meet demand that is not met by the renewable energy power plant. All scenarios are compared based on the lowest net present cost of supplying the specified electrical loads to serve 25,000 homes in Rio Vista, California over 25 years of operation. The detailed economics and electric power production of both wind and solar combined with energy storage for any size of wind facility, solar facility, battery facility, and hydrogen facility are analyzed with a MATLAB computer program developed for this work. The program contains technical and economic models of each of these systems working in different combinations. Current equipment c (open full item for complete abstract)

Committee: James Menart Ph.D. (Advisor); Hong Huang Ph.D. (Committee Member); Mitch Wolff Ph.D. (Committee Member) Subjects: Alternative Energy; Energy; Engineering

Doctor of Philosophy, The Ohio State University, 2022, Chemistry

Increasing concerns about carbon emissions has led to the global adoption of renewable energy initiatives. Direct integration of renewable energy sources, however, is difficult because of the intermittency of such sources. Furthermore, direct integration would overload the grid and lead to blackouts. Thus, grid-scale electrical energy storage is required to store and provide energy on-demand. Redox flow batteries have attracted attention as a scalable, inexpensive storage technology. Flow batteries store energy in solvated, redox-active electrolytes, as opposed to conductive, solid materials. These solutions are stored in separated reservoirs and are flowed to the electrochemical cell to cycle the redox-active compound. Energy stored in this fashion decouples energy and power, which allow for increased operational control. While many electrolytes exist, few electrolyte examples have achieved commercialization because of low solubility and low cell voltage. Redox-targeting flow batteries have emerged as an improvement to classic flow technology. Rather than storing energy in solution, redox -targeting flow batteries store energy in an insoluble solid while a solubilized electrolyte serves to shuttle electrons from the electrochemical cell to the solid. This strategy serves to combine the high energy density of solid-state batteries and scalability of flow batteries. Current redox targeting technology is mainly limited to the use of inorganic solid materials. These materials are cycle by an intercalation mechanism, which requires low current densities that lead to long cycle times. Furthermore, pairing shuttles with these materials are difficult because of distinct redox potentials and electron transfer rates of these solids. Our efforts focused on the development of an all-organic redox targeting flow battery. Organic materials generally do not operate based on intercalation mechanisms and the synthetic flexibility of organic compounds allow for the fin (open full item for complete abstract)

Committee: Christo Sevov (Advisor); Yiying Wu (Committee Member); Jovica Badjic (Committee Member) Subjects: Chemistry; Energy

Master of Sciences (Engineering), Case Western Reserve University, 2018, Chemical Engineering

Inexpensive and scalable energy storage is necessary for the transition to a cleaner, more sustainable, electricity grid. The Acid-Base Energy Storage System (ABESS) utilizes an extremely inexpensive, safe, and abundant electrolyte, can be deployed anywhere without geographical constraints, and is predicted to be economical at very large energy storage capacities and long discharge times. The ABESS stores energy by utilizing the potential difference created by a proton (H+) concentration gradient in a saltwater electrolyte. The coulombic efficiency (ηC ) of an ABESS is unknown and it is crucial to understand for further development. In this thesis, the mass transport of the active species through Nafion® was measured and modeled in the charging of an ABESS under a high salt environment to determine ηC limitations. A macro-homogeneous model based on dilute solution theory utilizing Nernst-Planck equations was developed to relate ηC to the current density of an ABESS during charging. Effective diffusivities and transference numbers of sodium and active species under various electrolyte conditions were experimentally determined and reported for an ABESS operating with a concentrated saltwater electrolyte and a Nafion® separator. Using a Nafion®-212 membrane and a saturated sodium sulfate electrolyte at room temperature (∼1.5M Na2SO4 at 22°C ± 1.0°C), a maximum ηC of 86.7% ± 2.5% was measured during charging at 100 mA/cm2 up to a concentration of 0.5N Acid/Base in the respective reservoirs. These are promising results and show that a full battery will be able to achieve a 70% - 75% overall energy efficiency, comparable to other flow battery technologies.

Committee: Jesse Wainright Dr. (Advisor); Robert Savinell Dr. (Committee Member); Christine Duval Dr. (Committee Member) Subjects: Alternative Energy; Chemical Engineering; Energy; Engineering

Master of Science (M.S.), University of Dayton, 2011, Chemical Engineering

The specific energy storage capacities of phase change materials (PCMs) increase with temperature, leading to a lack of thermal management (TM) systems capable of handling high heat fluxes in the temperature range from 20°C to 100°C. State of the art PCMs in this temperature range are usually paraffin waxes with energy densities on the order of a few hundred kJ/kg or ice slurries with energy densities of the same magnitude. However, for applications where system weight and size are limited, it is necessary to improve this energy density by at least an order of magnitude. The compound ammonium carbamate (AC), [NH4 ][H2NCOO], is a solid formed from the reaction of ammonia and carbon dioxide which endothermically decomposes back to ammonia and carbon dioxide in the temperature range of 20°C to 100°C with an enthalpy of decomposition of 2,010 kJ/kg. Various methods to use this material for TM of low-grade, high-flux heat have been evaluated including: bare powder, thermally conductive carbon foams, thermally conductive metal foams, hydrocarbon based slurries, and a slurry in ethylene glycol or propylene glycol. A slurry in glycol is a promising system medium for enhancing heat and mass transfer for TM. Small-scale system level characterizations of AC in glycol have been performed and results indicate that AC is indeed a promising material for TM of low-grade heat. It has been shown that pressures on the order of 200 torr will achieve rapid decomposition and thermal powers of over 300 W at 60°C have been found, demonstrating the capability of AC.

Committee: Kevin Myers D.Sc., P.E. (Committee Chair); Douglas Dudis Ph.D. (Advisor); Robert Wilkens Ph.D., P.E. (Committee Member) Subjects: Chemical Engineering

Master of Science (M.S.), University of Dayton, 2023, Aerospace Engineering

The main objective of this project is to investigate the performance of Phase Change Materials as the Heat Exchange media in a solar thermal propulsion system. The secondary objective is to visualize and develop the solar thermal propulsion system by running various ground tests using a solar simulator as power source. The project involves design, modelling and fabrication of a bench scale Solar Thermal Propulsion System that can be used to carry and deliver satellites to Moon or Mars' orbit from LEO. PCM's are essential for space travel since the solar energy needs to be stored for the spacecraft to successfully complete the interplanetary missions which consume time and fuel. Without the energy storage system, the spacecraft might need to use conventional fuel ignition systems, which cost money to manufacture and implement in the spacecraft. In this system, the energy from solar light is concentrated into a small cavity through a parabolic reflector and is used to heat the PCM, which in turn heats the propellant and directs it through the nozzle to provide thrust adequate to travel in space. The prototype of the system is first designed using a CAD software and later fabricated into a bench scale model. The model is then set up in the laboratory and connected to a high flux solar simulator. Computational simulations and some test runs of the physical model would be conducted to analyze the performance of PCM in this system

Committee: Rydge Mulford (Committee Chair); Andrew Schrader (Committee Member); Jamie Ervin (Committee Member) Subjects: Aerospace Engineering; Energy; Mechanical Engineering

Doctor of Philosophy (Ph.D.), University of Dayton, 2023, Electrical Engineering

Lithium-ion batteries (LIBs) have transformed modern electronics and rapidly advancing electric vehicles (EVs) due to high energy, power, cycle-life, and acceptable safety. However, the comprehensive commercialization of EVs necessitates the invention of LIBs with much enhanced and stable electrochemical performances, including higher energy/power density, cycle-life, and operation safety but at a lower cost. An unprotected lithium-ion battery (LIB) cell cathode using lithium metal anode and organic carbonate liquid electrolyte undergoes significant structural damage during the cycling (Li+ intercalation/ deintercalation) process. Also, a bare cathode in contact with a liquid electrolyte forms a resistive cathode electrolyte interface (CEI) layer. Both the cathode structure damage and CEI lead to rapid capacity fade. Different strategies have been used to mitigate the degradation of LIB electrodes, including designing electrolytes to enhance SEI/CEI formation, cycle stability, interface engineering with protective coatings to prevent the breakdown of active material particles during cycling, composition control of the electrode particles, synthetic optimization to control particle morphology, the use of composites made from conductive scaffolds and active materials and designing new electrode architectures to overcome volume changes and enhance transport properties. Cathode surface modification has been used to reduce CEI formation and structural damage, improving capacity retention, cycle life, energy density, power density, and safety of a LIB. Recently, the coating of the cathode with an intermediate layer (IL), which is transparent to Li+ conduction but impermeable to electrolyte solvent, has been developed to minimize CEI formation and structural damage. IL based on Li+ insulating ceramics, such as aluminum oxide (Al2O3), tin oxide (SnO2), and magnesium oxide (MgO), has been developed but to limited success in mitigating the above cathode degradation. The (open full item for complete abstract)

Committee: Dr. Jitendra Kumar (Committee Chair); Dr. Guru Subramanyam (Committee Member); Dr. Feng Ye (Committee Member); Dr. Vikram Kuppa (Committee Member) Subjects: Electrical Engineering; Energy; Engineering

Doctor of Philosophy, Case Western Reserve University, 2023, Macromolecular Science and Engineering

Polymer film capacitors are suitable for capacitive energy storage in the expanding market of electric vehicles and high-speed trains, as their advantages of high electric breakdown, long lifetime, and high ripple current tolerance. The state-of-the-art polymer capacitor material is biaxially oriented polypropylene (BOPP), due to its ultralow loss, long operating lifetime, and high breakdown strength. However, its temperature rating of ~85 °C limits its application in electric vehicles since the ambient temperature, where DC-link capacitors are installed, is around 140 °C. Multilayer technology has proved its potential to achieve high energy density, high breakdown strength, and high-temperature rating simultaneously. These multilayer films (MLFs) are composed of a high temperature/low loss polymer and a high dielectric constant polymer. Under extreme conditions (e.g., high electric fields and high temperatures), an important loss mechanism of AC electronic conduction occurs in MLF capacitors by homocharge injection at the metal electrode/polymer interfaces and subsequently charge recombination, leading to heat generation. In this dissertation, this mechanism was studied for high temperature polycarbonate (HTPC)/poly(vinylidene fluoride) (PVDF) MLFs with either HTPC (MLF@HTPC) or PVDF (MLF@PVDF) as the outer skin layers. Based on DC/AC breakdown strength, DC lifetime measurements, and electric displacement-electric field loop analysis on metal electrode/MLF/metal electrode capacitor devices, it is concluded that the charge injection can be largely minimized when aluminum is used as the metal electrode material and HTPC is used as skin layers. In addition, the Tg effect of three PC MLFs was also studied by dielectric breakdown, lifetime, and leakage current measurements. From the experimental results, we conclude that charge injection was largely reduced with HTPC MLFs, leading to significantly enhanced insulation properties with high breakdown strength and l (open full item for complete abstract)

Committee: Lei Zhu (Committee Chair); Geneviève Sauvé (Committee Member); Gary Wnek (Committee Member); Eric Baer (Committee Member) Subjects: Energy; Plastics

Master of Science, The Ohio State University, 2022, Mechanical Engineering

Modern households are becoming increasingly electrified with all-electric appliances, renewable energy sources, and electric vehicles. While these homes ultimately mitigate the rate of climate change; without a resilient grid, large-scale market penetration is infeasible. To support grid resilience, utility companies have began incentivizing homeowners to defer appliance loads to times of lower electricity via day-time variable pricing schemes. Modern homeowners enrolled in these programs can maximize their financial benefits by installing energy storage systems and energy management strategies which can schedule appliance loads, energy distribution, and energy consumption. The work in thesis focuses on the design of a home energy management system that schedules multiple smart appliances including plug-in hybrid and battery electric vehicle charging, operation of heating, ventilation, and air conditioning system, energy usage from solar photo-voltaic cells, energy storage and usage from stationary energy storage system, and power consumed from the grid. Considering a day-time variable pricing scheme, the energy management strategy minimizes electrical grid cost to the user, while minimizing user's discomfort in the form of temperature deviation from set-point and time of appliance completion from request. To achieve this goal, the home energy management strategy is formulated as a model predictive controller and at every time step a multi-objective function is minimized using a meta-heuristic algorithm genetic algorithm. The performance of the the home energy management strategy is analyzed by comparing results to a simplistic control strategy. A simulation campaign is conducted to compare the relative performance of the the home energy management strategy at a multitude of plant model settings such as house location, house size, stationary energy storage size, and others. Additionally, to ensure the the home energy management strategy does not significantly de (open full item for complete abstract)

Committee: Marcello Canova (Committee Member); Stephanie Stockar (Advisor) Subjects: Electrical Engineering; Energy; Engineering; Mechanical Engineering; Sustainability; Systems Design

Doctor of Philosophy (PhD), Ohio University, 2021, Chemical Engineering (Engineering and Technology)

Incorporation of potassium bifluoride (KF-HF) as an additive to lithium-halide electrolyte for thermal batteries was investigated. Results indicated that it is feasible to maintain a relatively high ionic conductivity at temperatures (250-300 C) lower than current thermal battery electrolytes (400-550 C). Mixtures of lithium fluoride and potassium bifluorides with the 40-60 wt.% provided the best ionic conductivity at 260 C. Ceramic felts are shown to be an effective alternative to widely used MgO. One of the major benefits of ceramic felts is their high porosity and low weight. LiSi/FeS2 thermal cells with YSZ and Al2O3 ceramic felt electrolyte/separators reported specific energy of 58.47 Wh kg-1 and 43.96 Wh kg-1. Pellet design pyrite (FeS2) cathodes for thermal batteries usually have low electronic conductivity. A new cathode design was developed using iron particles. By adding 11 wt.% Fe particles to the cathode the ohmic polarization was reduced by 17.5% while the available capacity was increased by 78% over the cell with traditional cathode pellet with no electrically conductive particle additives.

Committee: Gerardine Botte (Advisor); Valerie Young (Advisor) Subjects: Chemical Engineering; Energy; Engineering

Doctor of Philosophy (Ph.D.), University of Dayton, 2020, Mechanical Engineering

This dissertation focusses mainly on loads determination, building informatics, and geothermal energy systems. The first chapter is Low-Energy Opportunity for Multi-Family Residences: A Simulation-Based Study of a Borehole Thermal Energy Storage System. In this chapter, we propose a district borehole thermal solar energy storage (BTES) system for both retrofit and new construction for a multi-family residence in the Midwestern United States, where the climate is moderately cold with very warm summers. Actual apartment interval power and water demand data was mined and used to estimate unit level hourly space and water heating demands, which was subsequently used to design a cost-optimal BTES system. Using a dynamic simulation model to predict the system performance over a 25-year period, a parametric study was conducted that varied the sizes of the BTES system and the solar collector array. A life-cycle cost analysis concluded that is it possible for an optimally-sized system to achieve an internal rate of return (IRR) of 11%, while reducing apartment-wide energy and carbon consumption by 46% The promise for district-scale adoption of BTES in multi-family residences is established, particularly for new buildings. In the second chapter (Alternate Approach to the Calculation of Thermal Response Factors for Vertical Borehole Ground Heat Exchanger Arrays Using an Incomplete Bessel Function), we presents another methodology for the calculation of dimensionless thermal response factors for vertical borehole ground heat exchanger (GHX) arrays, which is a concept introduced by Eskilson (1987). The presented method is based on a well-known solution to an analogous problem in the field of well hydraulics. This solution method, known mathematically as an incomplete Bessel function, and known in the field of well hydraulics as the `leaky aquifer function', describes the hydraulic head distribution in an aquifer with predominantly radial flow to a well combined with vertical (open full item for complete abstract)

Committee: Kevin P Hallinan Professor (Committee Chair); Andrew D. Chiasson Professor (Committee Member); Robert J. Brecha Professor (Committee Member); Robert B. Gilbert Professor (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy (Ph.D.), University of Dayton, 2019, Electrical and Computer Engineering

Electric power grids are currently undergoing a major transition from large centralized power stations to distributed generation in which small and flexible facilities produce power closer to where it is needed. This move towards a decentralized delivery of energy is driven by a combination of economic, technological and environmental factors. In recent years, the cost of renewable energy in the form wind turbines and solar PV has dropped dramatically due to advances in manufacturing and material science, leading to their rapid deployment across the US. To supplement the intermittent nature of wind and solar energy, there is a growing need for small, highly controllable sources such as natural gas turbines. With the fracking boom in the US, there is currently abundant natural gas to use for this purpose. The resulting proliferation of many small energy producers creates technical problems such as voltage and frequency control that can be addressed with battery storage, whose cost is also dropping. These factors are leading to a move away from large energy production facilities that require too much initial investment. Also, a distributed supply is more efficient and reliable. The threat of global climate change is creating pressure to increase the integration of distributed generation and information technology is now capable of managing a greater number of energy producers, utilizing a vast supply of information to predict supplies and demand and to determine optimal dispatching of energy. The move towards a higher percentage of renewable energy creates many interesting technical issues, many of which are due to the lack of control over the renewable resources. Energy dispatching between multiple sources, some controllable and some not, and multiple loads leads to a need for dispatching strategies that maximize the percentage of the load that is met with renewable energy. A growing aspect of this energy dispatch is a stream of information about energy demand, w (open full item for complete abstract)

Committee: Malcolm Daniels Dr. (Advisor) Subjects: Electrical Engineering; Energy; Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2019, Environmental Science

Reducing carbon dioxide (CO2) emissions is one of the most pressing issues facing the electricity system. Towards this end, prior work investigated generating electricity with geologically stored CO2 by using it to extract heat from sedimentary basins geothermal resources. This dissertation expands on this idea by developing and valuing approaches for CO2-based energy storage. In the first chapter, we investigate the value that three bulk energy storage (BES) approaches have for reducing system-wide CO2 emissions and water requirements: CO2-Bulk Energy Storage (CO2-BES), which is a CO2-based energy storage approach that uses a concentric-ring, pressure based (CRP-BES) design, Pumped Hydro Energy Storage (PHES), and Compressed Air Energy Storage (CAES). Our results suggest that BES could decrease system-wide CO2 emissions by increasing the utilization of wind, but it can also alter the dispatch order of regional electricity systems in other ways (e.g., increase in the utilization of natural gas power capacity and of coal power capacity, decrease in the utilization of nuclear power capacity). While some changes provide negative value (e.g., decrease in nuclear increased CO2 emission), the system-wide values can be greater than operating cost of BES. In the second and third chapters, we investigate two mechanisms for using CO2 for energy storage: storage of (1) pressure and (2) heat. For pressure storage, we investigated the efficacy of the CO2-BES system using the CRP-BES design over cycles of varying durations. We found that CO2-BES could time-shift up to a couple weeks of electricity, but the system cannot frequently dispatch electricity for longer durations than was stored. Also, the cycle duration does not substantially affect the power storage capacity and power output capacity if the total time spent charging, discharging, or idling is equal over a multi-year period. For thermal energy storage, we investigated the efficacy of using pre-heated CO2 and pre-h (open full item for complete abstract)

Committee: Jeffrey Bielicki (Advisor); Ramteen Sioshansi (Committee Member); Gil Bohrer (Committee Member); Brent Sohngen (Committee Member) Subjects: Alternative Energy; Energy; Engineering; Environmental Economics; Environmental Science

Doctor of Philosophy, The Ohio State University, 2018, Chemistry

With increasing energy demand and adverse effects of CO2 emissions, a future dependent of fossil fuels becomes more problematic. A source of clean and renewable energy is necessary to sustain further economic growth. Therefore, research into converting and storing solar energy has become an area of increased interest. Due to the intermittent nature of sunlight, storage of solar energy becomes as important as its conversion. This dissertation covers two strategies to overcome these challenges, (1) development of next generation large scale batteries that can store solar energy for use at a later time and (2) Integration of the two functions into an all-in-one device which can offer simultaneous solar energy conversion and storage. A promising new technology called potassium-oxygen batteries have the potential to meet the requirements of large scale energy storage and have high theoretical energy densities up to 4 times that of current lithium ion batteries at a much lower cost. The potassium metal anode has been identified as the largest limitation of this technology. Therefore, development of new potassium alloy anode materials or novel electrolytes that stabilize the potassium metal are two strategies to improve the safety and stability of the battery. Using electrochemical measurements and x-ray diffraction, a crystalline K3Sb alloy can undergo reversible electron storage for many cycles, resulting in a stable anode for potassium-oxygen batteries. Additionally, synthetic tuning of the electrolyte allows for highly concentrated electrolytes which result in a stabilized potassium metal interface. These two combinations make the potassium-oxygen battery a more commercially viable option. The second strategy to promote the use of renewable energy is development of a solar redox flow battery that can offer simultaneous solar energy conversion and storage. These devices are based on the direct integration of a photoelectrode into a redox flow battery. Under illumi (open full item for complete abstract)

Committee: Yiying Wu Dr. (Advisor); Joshua Goldberger Dr. (Committee Member); Anne Co Dr. (Committee Member); Heather Chandler Dr. (Committee Member) Subjects: Chemistry; Energy

Master of Science (M.S.), University of Dayton, 2017, Renewable and Clean Energy

Photovoltaic-thermal (PVT) technology is a relatively new technology that comprises a photovoltaic (PV) panel coupled with a thermal collector to convert solar radiation into electricity and thermal energy simultaneously. Since cell temperature affects the electrical performance of PV panels, coupling a thermal collector with a PV panel contributes to extracting the heat from the latter to improve its performance. In order to ensure a sufficient temperature difference between the PV cells and the working fluid temperature entering the thermal collector, the circulated water has to reject the heat that has been removed from the PV cells into a relatively colder environment. Borehole thermal energy storage (BTES), which is located underground, often serves as this relatively colder environment due to the stability of underground temperatures, which are usually lower than the working cell temperature. Use of BTES is especially beneficial in summer, when the degradation in cells efficiency is highest. In this thesis, the electrical, thermal, and economic performances of a PVT system are evaluated for three types of buildings -- residential, small office, and secondary school -- in two different climates in the United States, one of which is hot and the other is cold. For each case, two different scenarios are considered. In the first, a PVT system is coupled with BTES, and a ground-coupled heat pump (GCHP) is in use. In the second, a PVT system is coupled with BTES and no GCHP is in use. Each scenarios' GCHP performance is assessed as well. Both the PVT collectors and GCHP performances are evaluated over short and long-term to study the effect of continued ground heat imbalance on both technologies.

Committee: Andrew Chiasson Ph.D. (Committee Chair); Youssef Raffoul Ph.D. (Committee Member); Robert Gilbert Ph.D. (Committee Member) Subjects: Energy; Engineering; Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2017, Electrical and Computer Engineering

The advent of microgrids has shifted the focus from centralized power generation to a more distributed manner, involving a mix of different distributed energy resources (DERs). Reciprocating engine driven synchronous generators (referred as gensets) are a common DER used for distributed generation. One of the key concerns with such power networks is the aspect of frequency regulation under large disturbances, especially in an islanded mode of operation, without the support of the utility grid. This works looks at possible solution methods for mitigating large frequency disturbances in an islanded microgrid. Due to steep load changes, the gensets undergo large frequency swings and can be even vulnerable to stalling. The benefits of smart loads are analyzed in this work to prevent such occurrence by temporarily reducing the transient overload on gensets. Another solution to mitigate large frequency deviation is the integration of energy storage system (ESS), but the effectiveness depends on its operation as a grid-forming or a grid-following unit. Important metrics such as frequency nadir during load changes in the islanded microgrid are computed to show the usefulness of ESS in islanded microgrids. For this purpose, analytical methods using reduced-order models are developed and found to provide accurate estimates of frequency deviations under power system disturbances. Generally, ESS units are interfaced with an inverter and when operated in grid-forming mode can offer desired dynamic frequency behavior in an islanded microgrid. Similarly, other inverter-based DERs can also provide good frequency regulation as they share the larger portion of the transient overload compared to gensets. However, under certain scenarios the inverter-based DERs are found to collapse due to this large transient loading and can bring down the whole microgrid system as a result. A better coordination between the different DERs in a mixed source microgrid is facilitated in this work to gua (open full item for complete abstract)

Committee: Mahesh Illindala (Advisor); Jin Wang (Committee Member); Jiankang Wang (Committee Member); Alexander Lindsey (Committee Member) Subjects: Electrical Engineering

PhD, University of Cincinnati, 2016, Engineering and Applied Science: Materials Science

This research is focused on enhancing electrochemical properties/energy storage capabilities of graphene-polyimide composites. The composite's dense morphology/structure limits ionic penetration owing to high bulk resistances resulting in poor electrochemical performance. Modification of the composite's morphology by incorporation of facile pores during curing increases total available surface area to electrolyte species. Presence of pores increases adsorption sites for double layer formation and increases overall capacitance. In this work, aromatic polyimide precursors were reacted in the presence of nano-graphene fillers to synthesize graphene–polyimide composite films. The resulting composite was very stiff and dense with a high glass transition temperature (Tg) of ~ 400 oC and storage modulus of 7.20 GPa. Selective decomposition of a thermally labile poly(acrylic ester) resin introduced into the composite during synthesis creates pores of varying size and shapes which increases available surface area of embedded stacked graphene sheets available for ion adsorption and double layer formation. Proper control over pore size and specific surface area of pores was required to ensure good performance in terms of both power delivery rate and energy storage capacity. Dynamic mechanical studies on modified composite showed very good mechanical property while shifts in imide peaks to lower wave numbers in Raman and Fourier transform spectroscopy (FTIR) confirms presence of chemical interaction between graphene filler and polymer matrix confirming uniform dispersion of fillers in the material. Thermogravimetric analysis (TGA) shows thermal stability for the composite systems at temperatures above 700oC. To further optimize material's energy storage capabilities, a hybrid composite was formed by depositing relatively cheap nickel oxide onto the modified porous composite system by a two-step process. A remarkable improvement in electrochemical properties up to an ord (open full item for complete abstract)

Committee: Jude Iroh Ph.D. (Committee Chair); Gregory Beaucage Ph.D. (Committee Member); Rodney Roseman Ph.D. (Committee Member); Dale Schaefer Ph.D. (Committee Member) Subjects: Materials Science

Master of Science (M.S.), University of Dayton, 2016, Electrical Engineering

Current trends in energy demands and supply are unsustainable – economically, environmentally and socially. If this trend continues then the amount of energy related emissions of carbon dioxide will be more than double by 2050 leading to uncontrollable global warming, and the increased fossil fuel demand will become a serious threat to the security of resources. Energy efficient buildings, energy demand forecasting, integration of renewable energy systems, and advanced energy storage technologies are the various measures that can support energy security and climate change. Energy storage technologies can help in better integration of our electricity and heating systems, and can play a crucial role in energy system de-carbonization. They can also assist in improving electricity grid stability, reliability and resilience, better distribution of energy and system efficiency. Most promising energy storage technologies are still in the early stages of development and are currently struggling to compete with other state-of-the-art market technologies due to high costs and reliability issues. This research focuses on forecasting the energy load-demand profile of any residential or commercial building on a monthly/hourly basis with variations in climate/weather. Based on the load forecasted, this work predicts suitable energy storage technologies that are cost-efficient, and can meet the forecasted heating and cooling demands of buildings in any region.

Committee: Jitendra Kumar Dr. (Committee Co-Chair); Guru Subramanyam Dr. (Committee Chair) Subjects: Energy; Engineering

Master of Science, University of Toledo, 2015, Engineering (Computer Science)

In this thesis, a new swarm intelligence based algorithm called Grey Wolf Optimizer (GWO) mimicking the social hierarchy and hunting behavior of grey wolves is used to optimally schedule the operation of Energy Storage Unit (ESU) in a green smart home to reduce the cost of power consumption and to balance the load on the grid. The smart home is primarily powered by the utility, which sends to the customer the hourly prices for the next day before the midnight when the new day rolls in. It is also integrated with local solar panels and wind turbines. Whenever the renewable energy resources are generating power, they can be used for meeting the household demand and to charge the Energy Storage Unit. The excess power generated is sold back to the utility through the grid at the same price at which the power is delivered to the customer during that hour. The GWO algorithm determines when and by how much, the ESU should be charged or discharged for each hour of the day for optimal cost saving. The proposed algorithm was tested with data obtained from the United States Department of Energy for Chicago region. The performance of the GWO algorithm is compared with the well known conventional Particle Swarm Optimization (PSO) Algorithm. The results show that the GWO outperforms the PSO and provides higher cost saving. The proposed method does not impose any restriction on the consumer regarding when to use which appliance, thus providing total freedom and still saving money.

Committee: Devinder Kaur (Committee Chair); Mansoor Alam (Committee Member); Srinivasa Vemuru (Committee Member) Subjects: Artificial Intelligence; Computer Science; Engineering

Doctor of Philosophy, Case Western Reserve University, 2014, Chemical Engineering

The superior electron carrier mobility, thermal conductivity, and mechanical properties of graphene have led to the rapid development of graphene-based applications for high speed electronics, chemical and biological sensing, optoelectronics, energy storage and conversion. However, the incorporation of graphene into these applications requires the precise connection of individual sheets at the molecular level with other materials where chemical interaction is significant. In this regard, the chemical functionalization of graphene has played a critical role in facilitating the integration of graphene into useful “building-blocks” or functional components in these applications. The functionalization of graphene can alter its electronic band structure, doping, and affinity for other organic, inorganic, and biological materials. The site specific functionalization of graphene is essential to modify the region-specific surface properties to gain specific characteristics required for particular applications and to covalently/non-covalently link graphene sheets of different properties together into various graphene-based devices. Controlled chemical modification could be a very useful approach to various multifunctional systems critical to applications such as nanoelectronics, nanophotonics, nanosensors, and nanoenergy systems. We describe a simple and effective modification method for functionalizing the two opposite surfaces of individual graphene sheets with different nanoparticles in either a patterned or non-patterned fashion. The asymmetric and patterned functionalization of graphene sheets with each of their two opposite surfaces attached by ZnO and Au NPs can serve as a platform upon which to build high performance electronics and photonic devices. In addition, we develop a novel approach for multicomponent symmetrical patterning metal/metal oxide nanoparticles on graphene involving region-speci¿c plasma treatment, followed by region-selective substrate-enhan (open full item for complete abstract)

Committee: Liming Dai (Advisor); Chung-Chiun Liu (Committee Member); Harihara Baskaran (Committee Member); Xiong Yu (Committee Member) Subjects: Chemical Engineering; Chemistry; Energy; Materials Science; Nanoscience; Nanotechnology