Matching Items (44)
Description
Microbial Electrochemical Cell (MXC) technology harnesses the power stored in wastewater by using anode respiring bacteria (ARB) as a biofilm catalyst to convert the energy stored in waste into hydrogen or electricity. ARB, or exoelectrogens, are able to convert the chemical energy stored in wastes into electrical energy by transporting electrons extracellularly and then transferring them to an electrode. If MXC technology is to be feasible for ‘real world’ applications, it is essential that diverse ARB are discovered and their unique physiologies elucidated- ones which are capable of consuming a broad spectrum of wastes from different contaminated water sources.
This dissertation examines the use of Gram-positive thermophilic (60 ◦C) ARB in MXCs since very little is known regarding the behavior of these microorganisms in this setting. Here, we begin with the draft sequence of the Thermincola ferriacetica genome and reveal the presence of 35 multiheme c-type cytochromes. In addition, we employ electrochemical techniques including cyclic voltammetry (CV) and chronoamperometry (CA) to gain insight into the presence of multiple pathways for extracellular electron transport (EET) and current production (j) limitations in T. ferriacetica biofilms.
Next, Thermoanaerobacter pseudethanolicus, a fermentative ARB, is investigated for its ability to ferment pentose and hexose sugars prior to using its fermentation products, including acetate and lactate, for current production in an MXC. Using CA, current production is tracked over time with the generation and consumption of fermentation products. Using CV, the midpoint potential (EKA) of the T. pseudethanolicus EET pathway is revealed.
Lastly, a cellulolytic microbial consortium was employed for the purpose ofassessing the feasibility of using thermophilic MXCs for the conversion of solid waste into current production. Here, a highly enriched consortium of bacteria, predominately from the Firmicutes phylum, is capable of generating current from solid cellulosic materials.
This dissertation examines the use of Gram-positive thermophilic (60 ◦C) ARB in MXCs since very little is known regarding the behavior of these microorganisms in this setting. Here, we begin with the draft sequence of the Thermincola ferriacetica genome and reveal the presence of 35 multiheme c-type cytochromes. In addition, we employ electrochemical techniques including cyclic voltammetry (CV) and chronoamperometry (CA) to gain insight into the presence of multiple pathways for extracellular electron transport (EET) and current production (j) limitations in T. ferriacetica biofilms.
Next, Thermoanaerobacter pseudethanolicus, a fermentative ARB, is investigated for its ability to ferment pentose and hexose sugars prior to using its fermentation products, including acetate and lactate, for current production in an MXC. Using CA, current production is tracked over time with the generation and consumption of fermentation products. Using CV, the midpoint potential (EKA) of the T. pseudethanolicus EET pathway is revealed.
Lastly, a cellulolytic microbial consortium was employed for the purpose ofassessing the feasibility of using thermophilic MXCs for the conversion of solid waste into current production. Here, a highly enriched consortium of bacteria, predominately from the Firmicutes phylum, is capable of generating current from solid cellulosic materials.
ContributorsLusk, Bradley (Author) / Torres, César I (Thesis advisor) / Rittmann, Bruce E. (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Arizona State University (Publisher)
Created2015
Description
Energy is one of the wheels on which the modern world runs. Therefore, standards and limits have been devised to maintain the stability and reliability of the power grid. This research shows a simple methodology for increasing the amount of Inverter-based Renewable Generation (IRG), which is also known as Inverter-based Resources (IBR), for that considers the voltage and frequency limits specified by the Western Electricity Coordinating Council (WECC) Transmission Planning (TPL) criteria, and the tie line power flow limits between the area-under-study and its neighbors under contingency conditions. A WECC power flow and dynamic file is analyzed and modified in this research to demonstrate the performance of the methodology. GE's Positive Sequence Load Flow (PSLF) software is used to conduct this research and Python was used to analyze the output data.
The thesis explains in detail how the system with 11% of IRG operated before conducting any adjustments (addition of IRG) and what procedures were modified to make the system run correctly. The adjustments made to the dynamic models are also explained in depth to give a clearer picture of how each adjustment affects the system performance. A list of proposed IRG units along with their locations were provided by SRP, a power utility in Arizona, which were to be integrated into the power flow and dynamic files. In the process of finding the maximum IRG penetration threshold, three sensitivities were also considered, namely, momentary cessation due to low voltages, transmission vs. distribution connected solar generation, and stalling of induction motors. Finally, the thesis discusses how the system reacts to the aforementioned modifications, and how IRG penetration threshold gets adjusted with regards to the different sensitivities applied to the system.
The thesis explains in detail how the system with 11% of IRG operated before conducting any adjustments (addition of IRG) and what procedures were modified to make the system run correctly. The adjustments made to the dynamic models are also explained in depth to give a clearer picture of how each adjustment affects the system performance. A list of proposed IRG units along with their locations were provided by SRP, a power utility in Arizona, which were to be integrated into the power flow and dynamic files. In the process of finding the maximum IRG penetration threshold, three sensitivities were also considered, namely, momentary cessation due to low voltages, transmission vs. distribution connected solar generation, and stalling of induction motors. Finally, the thesis discusses how the system reacts to the aforementioned modifications, and how IRG penetration threshold gets adjusted with regards to the different sensitivities applied to the system.
ContributorsAlbhrani, Hashem A M H S (Author) / Pal, Anamitra (Thesis advisor) / Holbert, Keith E. (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2020
Description
The operating temperature of photovoltaic (PV) modules has a strong impact on the expected performance of said modules in photovoltaic arrays. As the install capacity of PV arrays grows throughout the world, improved accuracy in modeling of the expected module temperature, particularly at finer time scales, requires improvements in the existing photovoltaic temperature models. This thesis work details the investigation, motivation, development, validation, and implementation of a transient photovoltaic module temperature model based on a weighted moving-average of steady-state temperature predictions.
This thesis work first details the literature review of steady-state and transient models that are commonly used by PV investigators in performance modeling. Attempts to develop models capable of accounting for the inherent transient thermal behavior of PV modules are shown to improve on the accuracy of the steady-state models while also significantly increasing the computational complexity and the number of input parameters needed to perform the model calculations.
The transient thermal model development presented in this thesis begins with an investigation of module thermal behavior performed through finite-element analysis (FEA) in a computer-aided design (CAD) software package. This FEA was used to discover trends in transient thermal behavior for a representative PV module in a timely manner. The FEA simulations were based on heat transfer principles and were validated against steady-state temperature model predictions. The dynamic thermal behavior of PV modules was determined to be exponential, with the shape of the exponential being dependent on the wind speed and mass per unit area of the module.
The results and subsequent discussion provided in this thesis link the thermal behavior observed in the FEA simulations to existing steady-state temperature models in order to create an exponential weighting function. This function can perform a weighted average of steady-state temperature predictions within 20 minutes of the time in question to generate a module temperature prediction that accounts for the inherent thermal mass of the module while requiring only simple input parameters. Validation of the modeling method presented here shows performance modeling accuracy improvement of 0.58%, or 1.45°C, over performance models relying on steady-state models at narrow data intervals.
This thesis work first details the literature review of steady-state and transient models that are commonly used by PV investigators in performance modeling. Attempts to develop models capable of accounting for the inherent transient thermal behavior of PV modules are shown to improve on the accuracy of the steady-state models while also significantly increasing the computational complexity and the number of input parameters needed to perform the model calculations.
The transient thermal model development presented in this thesis begins with an investigation of module thermal behavior performed through finite-element analysis (FEA) in a computer-aided design (CAD) software package. This FEA was used to discover trends in transient thermal behavior for a representative PV module in a timely manner. The FEA simulations were based on heat transfer principles and were validated against steady-state temperature model predictions. The dynamic thermal behavior of PV modules was determined to be exponential, with the shape of the exponential being dependent on the wind speed and mass per unit area of the module.
The results and subsequent discussion provided in this thesis link the thermal behavior observed in the FEA simulations to existing steady-state temperature models in order to create an exponential weighting function. This function can perform a weighted average of steady-state temperature predictions within 20 minutes of the time in question to generate a module temperature prediction that accounts for the inherent thermal mass of the module while requiring only simple input parameters. Validation of the modeling method presented here shows performance modeling accuracy improvement of 0.58%, or 1.45°C, over performance models relying on steady-state models at narrow data intervals.
ContributorsPrilliman, Matthew (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Phelan, Patrick (Thesis advisor) / Wang, Liping (Committee member) / Arizona State University (Publisher)
Created2020
Description
Accurate forecasting of electricity prices has been a key factor for bidding strategies in the electricity markets. The increase in renewable generation due to large scale PV and wind deployment in California has led to an increase in day-ahead and real-time price volatility. This has also led to prices going negative due to the supply-demand imbalance caused by excess renewable generation during instances of low demand. This research focuses on applying machine learning models to analyze the impact of renewable generation on the hourly locational marginal prices (LMPs) for California Independent System Operator (CAISO). Historical data involving the load, renewable generation from solar and wind, fuel prices, aggregated generation outages is extracted and collected together in a dataset and used as features to train different machine learning models. Tree- based machine learning models such as Extra Trees, Gradient Boost, Extreme Gradient Boost (XGBoost) as well as models based on neural networks such as Long short term memory networks (LSTMs) are implemented for price forecasting. The focus is to capture the best relation between the features and the target LMP variable and determine the weight of every feature in determining the price.
The impact of renewable generation on LMP forecasting is determined for several different days in 2018. It is seen that the prices are impacted significantly by solar and wind generation and it ranks second in terms of impact after the electric load. The results of this research propose a method to evaluate the impact of several parameters on the day-ahead price forecast and would be useful for the grid operators to evaluate the parameters that could significantly impact the day-ahead price prediction and which parameters with low impact could be ignored to avoid an error in the forecast.
The impact of renewable generation on LMP forecasting is determined for several different days in 2018. It is seen that the prices are impacted significantly by solar and wind generation and it ranks second in terms of impact after the electric load. The results of this research propose a method to evaluate the impact of several parameters on the day-ahead price forecast and would be useful for the grid operators to evaluate the parameters that could significantly impact the day-ahead price prediction and which parameters with low impact could be ignored to avoid an error in the forecast.
ContributorsVad, Chinmay (Author) / Honsberg, C. (Christiana B.) (Thesis advisor) / King, Richard R. (Committee member) / Kurtz, Sarah (Committee member) / Arizona State University (Publisher)
Created2019
Description
The goal of the presented research is using Electro Field-assisted Nano Ink Writing(EF-NIW) to deposit poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, or PEDOT, on a substrate to serve as a basis for designing high-efficiency, scalable solar cells. Through the analysis of parameters that affect electrospray deposition, methods to accurately produce a PEDOT film will be determined. With the finished, contingent film, tests for efficacy can be performed. The film will be analyzed for profilometry, determining the thickness of the film. The film will then be put up to a conductivity test.
ContributorsHutchins, John (Author) / Li, Xiangjia (Thesis director) / Zhu, Yizhen (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Dean, W.P. Carey School of Business (Contributor)
Created2021-12
Description
Thermophotovoltaic energy conversion is seen as a viable option for efficiently converting heat to electricity. There are three key components to a thermophotovoltaic (TPV) system: a heat source, a heat emitter and a photovoltaic (PV) cell. A heat source heats up the emitter which causes the emitter to release thermal radiation. The photons are absorbed by a PV cell when they are acting above the bandgap energy. The PV cell then generates electricity from this thermal radiation. In theory, efficiency of a TPV system can be well above 50%. In order for TPV to reach large-scale adaptation, an efficiency at or above 20% is needed. In this project, a high-temperature heater capable of reaching 1000K was developed. The heater involved a copper block machined to hold two cartridge heaters, as well as two thermocouples. It has an accompanying copper lid that can be screwed tight to the main block, with an emitter in between. There is an aperture to allow radiation through the casing towards the PV cell. Preliminary thermal analysis showed that the heater provides uniform temperature distribution across the emitter, which is necessary for proper radiation. A mounting system was also designed to implement the heater into the overall TPV system. Current work is being done to lower the radiation loss from the heater and mounting system, as well as implementation of all auxiliary components to begin testing. The maximum temperature of the heater, radiation heat flux received by the cell, and overall power output and efficiency of the system will be tested.
ContributorsDeffigos, Nikolas (Author) / Wang, Liping (Thesis director) / Milcarek, Ryan (Committee member) / Ni, Qing (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2021-12
Description
Fossil fuels have been the primary source of energy in the world for many decades. However, they are among the top contributors of the greenhouse gas emissions in the atmosphere. The objective of this research was to produce a more environmentally friendly biofuel from Algae-Helix and Salicornia biomasses. Experiments were conducted using a hydrothermal liquefaction (HTL) technique in the HTL reactor to produce biofuel that can potentially replace fossil fuel usage. Hydrothermal Liquefaction is a method used to convert the biomass into the biofuels. HTL experiments on Algae-Helix and Salicornia at 200°C-350°C and 430psi were performed to investigate the effect of temperature on the biocrude yield of the respective biomass used. The effect of the biomass mixture (co-liquefaction) of Salicornia and algae on the amount of biocrude produced was also explored. The biocrude and biochar (by-product) obtained from the hydrothermal liquefaction process were also analyzed using thermogravimetric analyzer (TGA). The maximum biocrude yield for the algae-helix biomass and for the Salicornia biomass were both obtained at 300°C which were 34.63% and 7.65% respectively. The co-liquefaction of the two biomasses by 50:50 provided a maximum yield of 17.26% at 250°C. The co-liquefaction of different ratios explored at 250°C and 300°C concluded that Salicornia to algae-helix ratio of 20:80 produced the highest yields of 22.70% and 31.97%. These results showed that co-liquefaction of biomass if paired well with the optimizing temperature can produce a high biocrude yield. The TGA profiles investigated have shown that salicornia has higher levels of ash content in comparison with the algae-helix. It was then recommended that for a mixture of algae and Salicornia, large-scale biofuel production should be conducted at 250℃ in a 20:80 salicornia to algae biocrude ratio, since it lowers energy needs. The high biochar content left can be recycled to optimize biomass, and prevent wastage.
ContributorsLuboowa, Kato Muhammed (Co-author) / Laideson, Maymary (Co-author) / Deng, Shuguang (Thesis director) / Nielsen, David (Committee member) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
As the need for environmentally friendly and renewable fuel sources rises, many are considering alternative fuel sources, such as solar power. The device explored in this report uses solar power, in theory, to heat a metal oxide, cerium oxide, to a desired temperature. At specific temperatures and pressures, a reaction between an input gas, carbon dioxide or water vapor, and the metal oxide may produce fuel in the form of hydrogen or carbon monoxide. In order to reach the temperatures required by the reaction, a filament inside a high-temperature radiant heater must be heated to the desired temperature. In addition, the system’s pressure range must be satisfied. A pressure and temperature measurement device, as well as a voltage control, must be connected to an interface with a computer in order to monitor the pressure and temperature of different parts of the system. The cerium oxide element must also be constructed and placed inside the system. The desired shape of the cerium oxide material is a tube, to allow the flow of gas through the tubes and system and to provide mechanical strength. To construct the metal oxide tubes, they need to be extruded, dried, and sintered correctly. All the manufactured elements described serve an essential purpose in the system and are discussed further in this document.
This report focuses on the manufacturing of ceria tubes, the construction of a high-temperature radiant heater filament, and the implementation of a pressure measurement device. The manufacturing of ceria tubes includes the extrusion, the drying, and the sintering of the tubes. In addition, heating element filament construction consists of spot-welding certain metals together to create a device similar to that of a light bulb filament. Different methods were considered in each of these areas, and they are described in this report. All of the explorations in this document move towards the final device, a thermochemical reactor for the production of hydrogen (H2) and carbon monoxide (CO) from water (H2O) and carbon dioxide (CO2).
The results of this report indicate that there are several important manufacturing steps to create the most desirable results, in terms of tube manufacturing and heating element design. For the correct tube construction, they must be dried in a drying rack, and they must be sintered in V-groove plates. In addition, the results of the heating element manufacturing indicate that the ideal heating element filament needs to be simple in design (easily fixed), cost-effective, require little construction time, attach to the ends of the system easily, provide mechanical flexibility, and prevent the coil from touching the walls of the tube it lies in. Each aspect of the ideal elements, whether they are tubes or heating elements, is explored in this report.
This report focuses on the manufacturing of ceria tubes, the construction of a high-temperature radiant heater filament, and the implementation of a pressure measurement device. The manufacturing of ceria tubes includes the extrusion, the drying, and the sintering of the tubes. In addition, heating element filament construction consists of spot-welding certain metals together to create a device similar to that of a light bulb filament. Different methods were considered in each of these areas, and they are described in this report. All of the explorations in this document move towards the final device, a thermochemical reactor for the production of hydrogen (H2) and carbon monoxide (CO) from water (H2O) and carbon dioxide (CO2).
The results of this report indicate that there are several important manufacturing steps to create the most desirable results, in terms of tube manufacturing and heating element design. For the correct tube construction, they must be dried in a drying rack, and they must be sintered in V-groove plates. In addition, the results of the heating element manufacturing indicate that the ideal heating element filament needs to be simple in design (easily fixed), cost-effective, require little construction time, attach to the ends of the system easily, provide mechanical flexibility, and prevent the coil from touching the walls of the tube it lies in. Each aspect of the ideal elements, whether they are tubes or heating elements, is explored in this report.
ContributorsCaron, Danielle (Author) / Milcarek, Ryan (Thesis director) / Ermanoski, Ivan (Committee member) / Stechel, Ellen (Committee member) / Mechanical and Aerospace Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This project seeks to provide a general picture of the economic dependence on fossil fuels per County in the United States. The purpose for this study is creating a foundation for conversations about the future of fossil fuel workers and counties that depend heavily on fossil fuels. The main indicators utilized for this were employment and payroll data extracted from United States Census Bureau’s County Business Patterns dataset. A section on similarities between fossil fuel workers and other occupations was included, which shows possible alternative industries for fossil fuel workers. The main goal of the project is to provide possible solutions for mitigating job losses in the future. Some proposed solutions include retraining, expanding higher education, and investing in new industries. It is most important for future work to include input from most vulnerable counties and understand the social and cultural complexities that are tied to this problem.
ContributorsRamirez Torres, Jairo Adriel (Author) / Miller, Claek (Thesis director) / Shutters, Shade (Committee member) / Watts College of Public Service & Community Solut (Contributor) / Electrical Engineering Program (Contributor) / Economics Program in CLAS (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Ensuring that people across the globe have enough water and electricity are two large issues that continue to grow. This study performs a test on whether using solar photovoltaic modules to shade water can potentially help diminish the issues of water and power. Using the setup of a PV module shading water, a stand-alone PV module, and unshaded water, it was found that shading water can reduce evaporation and lower PV module operating temperature at the same time. Using averaged data from two days of testing, the volume per unit surface area of water that evaporated per hour was 0.319 cm3/cm2 less for the shaded water compared to the unshaded water. The evaporation rates found in the experiment are compared to those of Lake Mead to see the amount of water lost on a large scale. For the operating temperature of the PV module, the module used for shading had a consistently lower temperature than the stand-alone module. On the first day, the shading module had an average temperature 5.1 C lower than the stand-alone module average temperature. On day two, the shading module had an average temperature 3.4 C lower than the stand-alone module average temperature. Using average temperatures between the two days from 10:30am and 4:45pm, the average daily temperature of the panel used for shading was 4.5C less than the temperature of the stand-alone panel. These results prove water shading by solar PV modules to be effective in reducing evaporation and lowering module operating temperature. Last, suggestions for future studies are discussed, such as performance analysis of the PV modules in this setting, economic analysis of using PV modules as shading, and the isolation of the different factors of evaporation (temperature, wind speed, and humidity).
ContributorsLee, John C (Author) / Phelan, Patrick (Thesis director) / Roedel, Ronald (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Mechanical and Aerospace Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05