Browsing by Author "Carpenter, Joseph"
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Item Advanced Heat Flux Estimation and Non-Intrusive Flow Measurement Using Inverse Heat Conduction and Machine Learning Techniques(University of Alabama Libraries, 2025) Peruchi Pacheco Da Silva, Ramon; Samadi, Forooza; Woodbury, Keith A.Non-intrusive measurements are increasingly essential in industrial applications due to their ability to monitor processes without disrupting operations. However, most commercially available non-intrusive flow meters are prohibitively expensive. This work investigates the use of a low-cost band heater to enable both flow measurement and fault detection, offering a practical alternative for real-time diagnostics in thermal-fluid systems. The first study characterizes the transient heating behavior from a band heater to a pipe using Inverse Heat Conduction Problem (IHCP) techniques. Experiments with heating durations of 5, 10, and 20 seconds were conducted without flow, using Type-T thermocouples to record surface temperatures. Five different heat conduction models were evaluated, demonstrating that simplified models can yield comparable results to more complex formulations with significantly reduced computational effort. The system was found to reach steady thermal energization within 10-12 seconds. Notably, measured heat flux values deviated from the manufacturer's nominal specification of 58.9 kW/m2. The second study employs a coupled inverse problem to simultaneously estimate the inner and outer heat fluxes of the band heater, as well as its thermal diffusivity. A physics-based model using Green's functions and exact solutions was developed to represent the annular geometry of the heater with internal heat generation. This model successfully demonstrates the feasibility of capturing directional heat flux distributions and material thermal properties under realistic operating conditions, showing that inner outer heat fluxes.The third study presents the development of a low-cost, non-intrusive flow meter and fault detection system for monitoring steady-state water flow in stainless steel pipes. Surface temperature data collected during 60-second heating cycles were used to train machine learning models. Volumetric flow rates ranging from 5.99x10-4 to 2.39x10-3 m3/s were predicted using regression models, while classification models were applied for fault detection. The Fine Tree regression model achieved a RMSE of 1.3x10-4 m3/s and an R2 of 0.94, while the Bagged Trees classifier achieved an accuracy, precision, recall, and F1-score of 0.997. The proposed system is priced at under 10% of the cost of commercially available alternatives, making it a promising solution for cost-sensitive applications.Item Advancing Sustainable Transportation and Aviation: a Multi-Scale Analysis of Zero-Emission Vehicles, Green Hydrogen Production, and E-Fuel Integration(University of Alabama Libraries, 2025) Jahami, Mahdi; Khandelwal, BhupendraThe transportation and aviation sectors are major greenhouse gas (GHG) emitters, necessitating scalable decarbonization strategies. The 2035 zero-emission light-duty vehicle (LDV) goal and aviation's 2050 net-zero target underscore the need for sustainable alternatives. However, green hydrogen production scalability, renewable energy integration, and infrastructure challenges persist. Existing research lacks a unified framework integrating emissions modeling, life cycle assessments (LCAs), and renewable energy system optimization. This study addresses these gaps by developing optimized renewable energy systems for green hydrogen production and growth for powered Fuel Cell Electric Vehicles (FCEVs) and Sustainable Aviation Fuels (SAFs)/e-fuels. A comprehensive assessment of California's gasoline and hybrid vehicle fleet was conducted through an LCA to quantify environmental impact. While prior studies analyzed emissions, they often neglected economic and regulatory factors crucial to transition success. This research formulated and integrated LCA with forecasting models, including Autoregressive Integrated Moving Average (ARIMA) and Seasonal ARIMA (SARIMAX), to evaluate the feasibility of full LDV decarbonization by 2035. The analysis highlighted a shortfall in zero-emission vehicle (ZEV) adoption under current initiatives, underscoring the need for accelerated interventions. Unlike previous studies that compared Battery Electric Vehicles (BEVs) and FCEVs separately, this research examined a full transition to FCEVs, incorporating infrastructure, economic feasibility, and policy implications.To enable large-scale hydrogen adoption, this research evaluated multiple hydrogen production pathways, including Steam Methane Reforming (SMR), electrified SMR (e-SMR), and Electrolysis, integrated with renewable energy systems such as Concentrated Solar Towers (CST), Photovoltaic (PV), and Wind Turbines. A novel e-SMR process configuration was developed, replacing fossil fuel combustion with resistance heating powered by renewables, enhancing hydrogen yield while minimizing CO₂ and other emissions. Additionally, the study modeled oxygen production from electrolysis and examined economic sales pathways to improve viability. A techno-economic model was developed to evaluate efficiency, emissions reductions, and investment feasibility while globalizing optimized green hydrogen production designs for diverse geographic and climatic conditions.Beyond LDVs, this study extends the developed modeling approaches to the aviation sector, demonstrating their versatility in evaluating large-scale SAF and e-fuel integration. Using SARIMAX forecasting, aviation fuel demand through 2050 was analyzed under various SAF adoption scenarios. Unlike previous studies that treated e-fuels as supplementary, this research evaluates full-scale transition feasibility, engineers and configures the renewable hydrogen infrastructure necessary for achieving net-zero aviation.Item Analysis of Combustion and Emissions Characteristics of Butanol Isomers in a Single Cylinder Heavy Duty Compression Ignition Engine(University of Alabama Libraries, 2025) Gray, Justin; Srinivasan, KalyanInternal combustion (IC) engines are essential in transportation, agriculture, and power generation, yet they are significant contributors to harmful environmental pollutants, including nitrogen oxides (NOₓ) and particulate matter. Compression ignition (CI) engines, widely favored for their superior thermal efficiency compared to spark ignition (SI) engines, predominantly rely on diesel fuel, exacerbating environmental and health concerns due to their high NOₓ and black smoke emissions. While electrification of the medium- to heavy-duty vehicle (MHDV) sector through battery electric vehicles (BEVs) and fuel cell electric vehicles holds promise, widespread adoption is hindered by challenges such as limited driving ranges and inadequate recharging infrastructure. As a viable alternative, renewable fuels such as biobutanols have garnered attention for their potential to reduce greenhouse gas emissions and mitigate environmental impacts. Among these, n-butanol, with its oxygenated structure and favorable combustion properties, emerges as a promising candidate to replace diesel in dual-fuel CI engines. However, its low reactivity and high combustion sensitivity at standard intake temperatures present challenges for direct ignition. Dual-fuel combustion, wherein butanol is ignited using a diesel pilot injection, provides an effective solution, allowing for substantial diesel replacement without requiring powertrain modifications. This dissertation investigates the combustion characteristics of n-butanol and iso-butanol in dual-fuel CI engines, focusing on their performance relative to conventional diesel. A series of experiments were conducted under controlled conditions, including sweeps of start-of-injection (SOI) timing, pilot energy substitution (PES) ratios, rail pressure, and boost pressure. The results highlight optimal operating points for minimizing engine-out emissions such as NOₓ, particulate matter, carbon monoxide, and hydrocarbons. Key findings demonstrate that a fixed SOI of 40° before top dead center (bTDC) yields the lowest NOₓ emissions for both n- and iso-butanol. PES and rail pressure optimizations further refine the balance between emissions and combustion efficiency, while boost pressure studies reveal that lower levels enhance fuel conversion efficiency by reducing CO emissions. The results provide a comprehensive understanding of how dual-fuel combustion of butanol isomers can enhance engine performance, reduce environmental impact, and maintain operational efficiency in MHDVs. This research contributes valuable insights into the viability of n-butanol and iso-butanol as cleaner, renewable alternatives to diesel, supporting pathways to sustainable and efficient transportation solutions.Item Confined Tube Aeration System for Aquaculture and Wastewater Industries(University of Alabama Libraries, 2023) Mahmud, Roohany; Woodbury, KeithThis dissertation proposes a novel bubble-based aeration system known as 'Confined Tube Aeration (CTA)', which uses a Venturi injector as the bubble generation device and connects to a coiled pipe network after the Venturi outlet as a mixing chamber where the air-water mass transfer occurs. In this work, to analyze the effectiveness of this proposed system, several experiments are conducted, and numerical (Discrete Bubble Model) analyses are also performed to optimize the system performance. A lab-scale simple CTA system is built using a single pump, one 1-inch Venturi, and a coiled pipe network, and experiments are conducted to analyze its performance. Results from the numerical model also conform well with experimental results. Two sizes of Venturi injectors, 1-inch and 4-inch, are investigated numerically to identify their performances in a CTA system. Suction air flow, bubble size, volume fractions, and injector efficiency are also analyzed. The 4-inch injector is found to perform better in terms of oxygen transfer rate and per unit of power requirement for that specific oxygen transfer rate at standard conditions. CTA system with multiple injectors arranged in parallel connections is also studied. Experimental data show that the 2-injector system performs better than the 1-injector and 3-injector systems. When pump speed is slowed down using a VFD, the performance of the 1-injector system is greatly improved. It is also observed that, at a larger-sized CTA tube, the mass transfer efficacy is improved, and SAE also improves as the pump's hydraulic energy input remains constant. An additional benefit of this proposed technology is its simplistic design which may incur reduced installation and maintenance costs compared to the existing porous bubble diffuser and mechanical aerator system. This proposed technology can be easily retrofitted to the existing aeration system without requiring large-scale modifications of the treatment plant's aeration techniques. Additionally, the flexibility of this system to build outside of the aeration tank can be considered for retrofitting in existing treatment plants. Aquaculture can specifically benefit from this technology as it does not require a deep aeration pond for the bubbles to transfer oxygen to the water.Item Development and Modelling of Self-Sufficient Wastewater Treatment with Near Zero Emissions(University of Alabama Libraries, 2022) Erguvan, Mustafa; Amini, Shahriar; University of Alabama TuscaloosaA report published by the United Nations Water states that access to clean water will be a significant problem for more than 6 billion people by 2050 with population and water demand increasing. So as to mitigate water shortages, wastewater recovery with proper treatment can have an important contribution. Apart from water shortage, the water-energy-nexus (WEN) has been a key consideration owing to close connection and dependency of water and energy to each other. WEN also plays a key role in wastewater treatment plants (WWTPs), especially in developed countries, due to the fact that treatment of wastewater requires a significant amount of electricity usage. In this dissertation, two different models are developed to investigate the self-sufficiency of WWTPs in terms of energy with near-zero emissions. Chapter 1 discusses current and past studies involving the water energy nexus, wastewater treatment methods, activated sludge process, biomass conversion methods, anaerobic digestion, biogas utilization, self-sufficient WWTPs, CO2 capture techniques as well as oxy – fuel combustion processes. In the second chapter, a numerical model has been created to investigate the energetical self-sufficiency of a novel integrated energy system in a WWTP. The proposed system consists of an activated sludge process, an anaerobic digester, a Brayton cycle, and a Rankine cycle. In order to investigate energy and exergy efficiencies along with self-sufficiency ratio, several parametric studies have been conducted by varying some decision variables. While biological oxygen demand and dissolved oxygen level have been varied in the WWTP part, turbine inlet temperature, compression ratio, and preheater temperature have been used as decision variables in the power cycle. This work presented here suggests that up to 109% of the energy needed to treat wastewater can be provided using the proposed system. The optimum values and dominant parameters to achieve the highest self-sufficiency ratio have been determined as well. The highest exergy efficiencies for the WWTP, cogeneration system and overall system were found to be 58.36%, 44.59%, 36.6%, respectively. A subsequent study investigates the integration of activated sludge process, anaerobic digestion, and an oxyfuel combustion process in a WWTP in order to provide a plant which is not only energetically self-sufficient but also emission free. Several parametric studies have been conducted to investigate their effects on the thermodynamic efficiencies as well as self-sufficiency ratio. The most dominant factors were found to be wastewater strength and compression ratio. While the overall exergy efficiencies varied from 19.38 to 32.59%, self-sufficiency ratio changed from 82.29 to 132.4%. In addition, more than 95% of the CO2 has been captured and recycled in the combustion chamber. This study proves that an energetically self-sufficient WWTP with near zero emission is plausible.Item Evaluation of the Environmental Impacts of Clean Hydrogen Production and CO2 Utilization from Carbon Capture and Direct Air Capture for Sustainable Chemical Synthesis(University of Alabama Libraries, 2025) Badger, Nicholas; Amini, ShahriarThe transition to low-carbon industrial processes requires an understanding of the environmental trade-offs associated with emerging chemical conversion technologies. Life cycle assessment (LCA) provides a framework for evaluating these processes against decarbonization goals. This dissertation applies LCA to assess the impacts of methanol production, formic acid synthesis, and hydrogen production, incorporating both carbon capture (CC) and direct air capture (DAC), focused on greenhouse gas emissions. The first chapter establishes an LCA for DAC-based methanol production, showing that wind- and hydro-powered DAC lead to the most net-negative emissions of all energy sources, reaching as low as -2.53 kg CO2 eq per kg methanol. The findings highlight that DAC’s energy source determines the feasibility of CO2-derived methanol. The second chapter applies multi-objective optimization to balance competing stakeholder environmental and economic priorities relative to an LCA study. In the illustrative example, the DAC-to-methanol system is optimized between profit margin of methanol sale and climate change impacts, with the model predicting that the best business strategy is a mix of photovoltaic and wind energy cases. The third chapter examines formic acid synthesis from DAC-derived CO2 regenerated with waste heat. Results show up to a 110% global warming potential (GWP) reduction compared to fossil-based routes, but economic challenges remain, with electricity costs and CO2capture efficiency as key factors. The fourth chapter evaluates the environmental impacts of hydrogen production via gas switching reforming (GSR), a natural gas reforming process that integrates CO2 capture. The LCA results showed that compared to steam methane reforming (SMR), GSR reduces CO2 emissions by 73% and requires 94% less energy than proton exchange membrane (PEM)electrolysis. The final chapter assesses the environmental impacts of various hydrogen production routes for methanol production, showing that integrating renewable electrolysis-based hydrogen lowers emissions by 89% compared to steam methane reforming with CC, while methanol from GSR hydrogen reduces emissions by 30%.Together, these chapters provide a comprehensive assessment of decarbonization technologies, highlighting the interconnected roles of hydrogen production, DAC, carbon utilization, and synthetic fuel synthesis. This research quantifies key trade-offs, guiding the development of sustainable chemical conversion technologies to support climate change mitigation.Item Using inverse regression models to create gray box models for industrial facilities(University of Alabama Libraries, 2018) Carpenter, Joseph; Woodbury, Keith A.; O'Neill, Zheng; University of Alabama TuscaloosaIndustrial facilities account for approximately one third of energy usage in the world, and effective energy assessments of these facilities require a reliable baseline energy model. Commercial and residential buildings are baselined with both simple change-point models and models that are more complex, such as Gaussian process and artificial neural networks, and these models are developed and tested with dense high-frequency data. However, industrial facilities are only baselined using change-point models, and data for the models are typically restricted to monthly utility bills and, therefore, generally sparse data. This investigation first compares the effectiveness of change-point models with that of Gaussian process models for baselining industrial facilities using only monthly utility billing information as data. Two case studies are presented to predict electricity usage and two case studies are presented to predict natural gas usage. Both change-point and Gaussian process models provided similar results, and both models meet the recommended NMBE and CV-RMSE from ASHRAE Guideline 14. Due to the simplicity and straight-forward equations of change-point models, they are better for regression analysis unless uncertainty is required. This study then investigates using three parameter cooling change-point regression models to determine the physical parameters, specifically overall heat transfer coefficient, surface area, and outdoor air mass flow rate of an industrial building through a simulation-based emulator. A simplified industrial building similar in size, energy usage, and physical parameters as a typical industrial facility was simulated in fifteen of the climate zones defined by ASHRAE using a whole building simulation program (i.e., EnergyPlus) to produce hourly data to illustrate and demonstrate the proposed approach. The change-point models showed poor results for finding the physical parameters using ambient air temperature as the independent variable. When using sol-air temperatures as the independent variable the change-point models were able to predict a lumped capacity of building envelope and outdoor air infiltration/ventilation within +/– 25 % error of actual (UA+ṀCP)/COP for most of the climate zones in the U.S.