Browsing by Author "Willson, Bryan, committee member"
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Item Open Access Application of force prediction to rotating equipment using pseudo-inverse techniques(Colorado State University. Libraries, 2010) Stansloski, Mitchell, author; Smith, Fred W., advisor; Wilbur, Paul, committee member; Willson, Bryan, committee member; Bienkiewicz, Bogusz, committee memberExtracting forcing functions for the purposes of signature analysis and load computation will improve root cause analysis on costly failures of rotating industrial equipment. By utilizing vibration signature response data and frequency response functions, both traditional troubleshooting technologies, the inverse method of force prediction has a high likelihood of becoming a useful force prediction tool to industrial maintenance staff. In prior research, force prediction using inverse methods has been studied and proven valid for a number of uni-axial structural configurations and external dynamic loadings. Minimal previously published studies have addressed computing internal forcing functions within rotating systems using these inverse techniques with experimental transfer functions. In this research, proof of concept is first obtained by applying the inverse method to a closed form solution of a rotating rigid shaft and disk assembly. Then, the method is validated with experimental data taken from a flexible rotating shaft system. Once validation is obtained, various rotating shaft speeds and loadings are studied. It is shown that this method can be an effective and accurate tool for root cause analysis in rotating industrial machinery.Item Open Access Combustion phenomena in biomass gasifier cookstoves(Colorado State University. Libraries, 2016) Tryner, Jessica, author; Marchese, Anthony J., advisor; Willson, Bryan, committee member; Yalin, Azer P., committee member; Peel, Jennifer, committee memberApproximately 2.8 billion people (~40% of the global population) rely on solid fuels, such as wood, charcoal, agricultural residues, and coal, for cooking. Exposure to emissions resulting from incomplete combustion of solid fuels leads to many adverse health impacts. These health impacts have motivated the development of solid-fuel cookstoves that reduce user exposure to carbon monoxide (CO) and fine particulate matter (PM2.5). In recent years, rating systems and emission rate targets for solid-fuel cookstove performance have been proposed. The aspirational targets included in these systems (e.g., Tier 4 in the ISO IWA tiers) have encouraged the development of cookstoves that reduce emissions of CO and PM2.5 by more than 50% and 95%, respectively, compared to a baseline three-stone fire. In a top-lit up draft (TLUD) gasifier cookstove, solid biomass fuel is gasified and the resulting gaseous fuel is mixed with secondary air above the fuel bed to produce the flame that heats the cooking surface. Household biomass cookstoves that utilize gasifier designs have attracted interest due to their demonstrated ability to emit less CO and PM2.5 per unit of energy delivered to the cooking surface than other cookstove designs. Unfortunately, highly variable performance has also been observed among gasifier cookstoves, and some have been found to emit more CO and PM2.5 than a three-stone fire. Accordingly, three studies were conducted to: (1) identify the sources of the observed variability; (2) characterize the manner in which stove design, fuel properties, and operating mode influenced performance; (3) gain insight into how secondary air velocity affected fuel-air mixing and the flame dynamics in the secondary combustion zone; and (4) evaluate whether or not the reductions in emission rates that are sought could be achieved with the TLUD design. In the first study, five natural draft TLUD design configurations were tested with two fuels (corn cobs and Lodgepole pine pellets) to investigate the variability in performance that had been observed in previous studies. The results indicated that stove design, fuel type, and operator behavior all influenced emissions. Four of the five configurations exhibited lower emissions when fueled with Lodgepole pine pellets than when fueled with corn cobs. Furthermore, large transient increases in CO emission rates were observed when stoves were refueled during operation by adding fresh biomass on top of the hot char bed that was left behind after the previous batch of fuel had gasified. An energy balance model was also developed, using temperature data collected from thermocouples mounted on each configuration, to identify the factors that contributed the most to sub-unity efficiency. The results illustrated that up to 60% of the energy input to the stove as fuel could be left over as char at the end of the test, and whether or not the energy in this char was subtracted from the energy in the fuel consumed during the test when calculating the thermal efficiency of a given configuration had a large effect on the calculated efficiency value. The manner in which cookstove design, fuel properties, and operator behavior affected TLUD performance was investigated in more detail in a second study. Seventeen different stove geometries, 4 primary air flow rates, 4 secondary air flow rates, 5 secondary air temperatures, 4 fuel moisture contents, and 4 different sfuel types were tested in a modular test bed using a procedure specifically designed to capture the low emissions observed during normal operation and the high emissions observed during refueling and char burnout. The lowest high-power emissions measured during normal operation were 1.6 g/MJd-1 CO (90% confidence interval (CI) = 1.1-2.1) and 18 mg/MJd-1 PM2.5 (90% CI = 17-19). These values were well below the Tier 4 targets of 8 g/MJd-1 CO and 41 mg/MJd-1 PM2.5, but post-refueling emissions were always above the Tier 4 targets. Higher secondary air velocities resulted in lower emissions. Changes in fuel type influenced the composition of the producer gas entering the secondary combustion zone during normal operation and sometimes resulted in order of magnitude changes in PM2.5 emissions. Temperature measurements taken in the fuel bed indicated that the stove operated as an inverted downdraft gasifier during normal operation and as a conventional updraft gasifier after refueling. Overall, the results suggest that efforts aimed at reducing users' exposure to CO and PM2.5 emissions from solid fuel combustion need to take fuel type and operator behavior, in addition to stove design, into consideration. The third study was designed to investigate the effects of secondary air velocity on the fuel-air mixing process and flame dynamics in the secondary combustion zone by employing high-speed imaging techniques. Images of OH* chemiluminescence, acetone (which served as a fuel tracer) planar laser-induced fluorescence (PLIF), and OH PLIF were collected at multi-kHz repetition rates in a burner designed to generate a two-dimensional replica of the secondary combustion zone in a gasifier cookstove. This burner featured two opposed planar jets that formed an inverse non-premixed flame in which the air and fuel were in cross flow. Images were collected for various air and fuel velocities. Regular deflecting oscillation of the jets, which has been reported previously for isothermal, non-reacting, unconfined opposed planar jets, was observed in some cases but appeared to be suppressed by convection in the vertical direction and buoyancy effects in other cases. The acetone PLIF images revealed that a high air jet velocity resulted in more extensive mixing of the air and fuel below the height of air injection. As a result, the reaction zone was located further below the top of the burner in comparison to the low air velocity case. These results suggest that higher air jet velocities may lead to lower emissions from gasifier cookstoves as a result of better fuel-air mixing and a lower reaction front location that allows more time for CO and PM to be oxidized before reactions are quenched by the cold cooking surface; however, the literature suggests that unconfined opposed axisymmetric jets do not exhibit deflecting oscillation behavior and, as a result, there are limitations associated with the use of opposed planar jets as a model for the secondary air jets in a gasifier cookstove.Item Open Access Development and testing of a multiplexing system for laser ignition of large bore natural gas engines(Colorado State University. Libraries, 2011) Reynolds, Adam Robert, author; Yalin, Azer, advisor; Willson, Bryan, committee member; Roberts, Jacob, committee memberConventional electric spark plugs present a hindrance to the continuing goals of higher efficiency and reduced emissions for large-bore natural gas engines. In order to achieve these goals, higher compression ratios and higher air-to-fuel ratios must be achieved relative to those currently allowed by conventional spark plugs. Laser ignition has been shown to work farther into the lean limit, and contrary to conventional electric spark plugs, laser sparks are easier to produce at higher pressures. Laser ignition has also been shown to reduce NOx emissions. This work presents efforts to design, build, and test a single-laser-to-multiple-cylinders multiplexed laser ignition system for use with a large bore natural gas engine. A fiber based laser delivery system was found to work for laser ignition on the bench-top. Results of bench top tests are presented.Item Open Access Economic and environmental evaluation of emerging electric vehicle technologies(Colorado State University. Libraries, 2023) Horesh, Noah, author; Quinn, Jason, advisor; Bradley, Thomas, committee member; Jathar, Shantanu, committee member; Willson, Bryan, committee memberAs the transportation sector seeks to reduce costs and greenhouse gas (GHG) emissions, electric vehicles (EVs) have emerged as a promising solution. The continuous growth of the EV market necessitates the development of technologies that facilitate an economically comparable transition away from internal combustion engine vehicles (ICEVs). Moreover, it is essential to incorporate sustainability considerations across the entire value chain of EVs to ensure a sustainable future. The sustainability of EVs extends beyond their usage and includes factors such as battery production, charging infrastructure, and end-of-life management. Techno-economic analysis (TEA) and life cycle assessment (LCA) are key methodologies used to evaluate the economic and environmental components of sustainability, respectively. This dissertation work uses technological performance modeling combined with TEA and LCA methods to identify optimal deployment strategies for EV technologies. A major challenge with the electrification of transportation is the end of life of battery systems. A TEA is utilized to assess the economic viability of a novel Heterogeneous Unifying Battery (HUB) reconditioning system, which improves the performance of retired EV batteries before their 2nd life integration into grid energy storage systems (ESS). The modeling work incorporates the costs involved in the reconditioning process to determine the resale price of the batteries. Furthermore, the economic analysis is expanded to evaluate the use of HUB reconditioned batteries in a grid ESS, comparing it with an ESS assembled with new Lithium-ion (Li-ion) batteries. The minimum required revenue from each ESS is determined and compared with the estimated revenue of various grid applications to assess the market size. The findings reveal that the economical market capacity of these applications can fully meet the current supply of 2nd life EV batteries from early adopters in the United States (U.S.). However, as EV adoption expands beyond early adopters, the ESS market capacity may become saturated with the increased availability of 2nd life batteries. Despite the growing interest in EVs, their widespread adoption has been hindered, in part, by the lack of access to nearby charging infrastructure. This issue is particularly prevalent in Multi-Unit Dwellings (MUDs) where the installation of chargers can be unaffordable or unattainable for residents. To address this, TEA methodology is used to evaluate the levelized cost of charging (LCOC) for Battery Electric Vehicles (BEVs) at MUD charging hubs, aiming to identify economically viable charger deployment pathways. Specifically, multiple combinations of plug-in charger types and hub ownership models are investigated. Furthermore, the total cost of ownership (TCO) is assessed, encompassing vehicle depreciation, maintenance and repair, insurance, license and registration, and LCOC. The study also conducts a cradle to grave (C2G) LCA comparing an average passenger BEV and a gasoline conventional vehicle (CV) using geographical and temporal resolution for BEV charging. The TCO is coupled with the C2G GHG emissions to calculate the cost of GHG emissions reduction. The analysis demonstrates that MUD BEVs can reduce both costs and GHG emissions without subsidies, resulting in negative costs of GHG emissions reduction for most scenarios. However, charging at MUDs is shown to be more expensive compared to single-family homes, potentially leading to financial inequities. Additional research is required to assess the advantages of public charging systems and commercial EVs. While home charging is typically the primary option for EVs, public charging infrastructure is necessary for long-distance travel and urgent charging. This is especially important for commercial vehicles, which rely on public charging to support their operational requirements. Various charging systems have been proposed, including Direct Current Fast Charging (DCFC), Battery Swapping (BSS), and Dynamic Wireless Power Transfer (DWPT). This work includes a comparison of the TCO and global warming potential (GWP) of EVs of various sizes, specifically examining the charging systems utilized to determine precise location-specific sustainability outcomes. Nationwide infrastructure deployment simulations are conducted based on the forecasted geospatial and temporal demand for EV charging from 2031 to 2050. The TEA and LCA incorporate local fuel prices, electricity prices, electricity mixes, and traffic volumes. To account for the adaptability of variables that highly influence TCO and GWP, optimistic, baseline, and conservative scenarios are modeled for EV adoption, electricity mixes, capital costs, electricity prices, and fuel prices. The change to TCO by switching from ICEVs to EVs is shown to vary across scenarios, vehicle categories, and locations, with local parameters dramatically impacting results. Further, the EV GWP depends on local electricity mixes and infrastructure utilizations. This research highlights the dynamic nature of EV benefits and the potential for optimal outcomes through the deployment of multiple charging technologies. In conclusion, this research underscores the significance of strategically deploying EV charging infrastructure and utilizing retired EV batteries for grid energy storage. Instead of posing a challenge at end of life, these batteries are shown to be a solution for grid energy storage. The study also highlights the economic advantages of different charging infrastructure types for EVs and their role in driving EV adoption, resulting in potential GHG emissions reductions and consumer savings. Ultimately, widespread EV adoption and decarbonization of electrical grids are pivotal in achieving climate goals.Item Open Access Engineering system modeling for sustainability assessment(Colorado State University. Libraries, 2016) Barlow, Jay, author; Quinn, Jason C., advisor; Willson, Bryan, committee member; Reardon, Kenneth F., committee memberThe increase in global greenhouse gas emissions has driven interest in the development of renewable energy sources. The commercial development of emerging renewable technologies like algal biofuels requires the identification of an economically viable production pathway. This study examined the sustainability of generating renewable diesel via hydrothermal liquefaction (HTL) of algal biomass from an attached growth architecture. Pilot-scale growth studies and laboratory-scale HTL experiments validated an engineering system model, which facilitated analysis of economic feasibility and environmental impact of the system at full scale. Techno-economic analysis (TEA) results indicate an optimized minimum fuel selling price (MFSP) of $11.90 gal-1, and life-cycle assessment (LCA) found a global warming potential (GWP) of -44 g CO2-e MJ-1 and net energy ratio of 0.33. Results from this work identified current gaps in sustainability assessment through TEA and LCA. Two needs were identified to improve sustainability assessment: the internalization of a carbon emission price into TEA and the consideration of the time-value of carbon emissions in LCA. With these effects considered, MFSP and GWP increase by 23% for the modeled biofuels system. Results from a harmonized model of an array of energy technologies indicate that prices for fossil-based energy increase 200% and GWP increases 25% when these factors are considered, whereas low-emitting technologies increase minimally in both metrics. Based on these findings, the development of improved sustainability assessment methodology is proposed.Item Open Access Environmental and economic evaluation of algal-based biofuels through geographically resolved process and sustainability modeling(Colorado State University. Libraries, 2023) Quiroz, David, author; Quinn, Jason C., advisor; Windom, Bret, committee member; Willson, Bryan, committee member; Reardon, Kenneth, committee memberAdvanced algal renewable fuels have been the subject of extensive research during the last decades. Their advantages over conventional biofuel feedstocks position algal biomass as a promising feedstock for the development of a sustainable and circular bioeconomy. Despite recent technological improvements, techno-economic analyses (TEAs) show that algae-derived fuels fail to be cost-competitive with petroleum fuels. Moreover, results from life-cycle assessments (LCAs) indicate declining greenhouse gas emissions when compared to petroleum fuels, but their water, health and air pollution impacts are still uncertain. This is explained by the fact that most published TEAs and LCAs of algal systems are not supported by high-resolution models and can only provide average sustainability metrics based on results from restricted data sources. These assessments often lack the resolution to correctly analyze the temporal and regional variations of biomass yields which have a direct impact on TEA and LCA metrics. Based on the current state of the field, there is a critical need to develop dynamic models that can inform sustainability assessments and consequently assist decision-making and technology development. This first part of this research work focuses on establishing the foundations for spatially explicit and temporally resolved LCA and TEA by developing and validating models that capture the thermal and biological dynamics of open algal cultivation systems. The modeling work is heavily focused on providing accurate predictions of evaporation losses in open algae raceway ponds and investigating the effects of evaporation rates on pond temperatures and growth rates. To date, this is the first modeling effort focused on predicting the evaporation losses of open algal ponds at the commercial scale. The outputs from the thermal model are then used to inform a biological algae growth model that is validated with experimental data representing the current biomass productivity potential. When integrated with hourly historical weather data, the modeling tools provide spatiotemporal mass and energy balances of the algal cultivation, dewatering, and conversion to fuel processes. These results are then leveraged with sustainability tools such as LCA and TEA to provide sustainability metrics at a high temporal and spatial scale. After developing a robust modeling framework, the modeling tool is leveraged with two distinct water LCA methods to provide a comprehensive assessment of the water impacts of algae-derived renewable diesel production across the United States. First, a water footprint analysis is conducted to understand the direct freshwater and rainwater consumption of algal cultivation and provide a framework for comparison to traditional biofuel feedstocks. The second method provides a county-level water scarcity footprint by analyzing the impact of algal systems on local water demand and availability. This assessment allows for the proper identification of potential algal sites for algal cultivation and locations where the deployment of algal systems will exacerbate local water stress. Ultimately, this research chapter provides the first holistic investigation of the water consumption and environmental water impacts of algal systems across the U.S. and establishes benchmarks for comparison to other fuels. Finally, the work comprising the third research chapter includes a novel global sustainability assessment that integrates the developed process modeling framework with regional-specific TEA and LCA. The spatially explicit TEA considers regional labor costs, construction factors, and tax rates to assess the economic viability of algal biofuels across 6,685 global locations. Similarly, a well-to-wheels LCA was performed by accounting for the regional life cycle impacts associated with electricity generation, hydrogen, and nutrient production across ten different environmental categories including health, air pollution, and climate impacts. This framework enables the identification of algal sites with optimal productivity potential, environmental impacts, and economic viability. Discussion focuses on the challenges and opportunities to reduce costs and environmental impacts of algal biofuels in various global regions.Item Open Access Evaluating the sustainability of agricultural systems using life cycle assessment and techno-economic analysis(Colorado State University. Libraries, 2021) Summers, Hailey, author; Quinn, Jason C., advisor; Marchese, Anthony J, committee member; Paustian, Keith, committee member; Willson, Bryan, committee memberIn a time of expansive population growth, our global resources have never been so strained; our contributions to a changing climate so significant. The International Panel on Climate Change recently addressed the need for focused effort toward reducing global resource depletion and greenhouse gas emissions (GHGs). As such, special attention has been given to some of the largest GHG emitting sectors in the world: energy, industry, and agriculture. This work focuses on using sustainability analysis to further understand agricultural processes and products, both novel and emerging. To quantify the environmental component of sustainability, life cycle assessment (LCA) is used because it is a well-established method for evaluating processes and products with respect to emissions. Similarly, techno-economic analysis (TEA) is used to understand the economic viability of various processes and products. In harmony, these assessments are used to evaluate the sustainable performance of various agricultural processes and products by identifying pathways to reduce environmental impact while concurrently increasing economic viability. Results enable targeted research to be highlighted that can advance early-stage development toward a sustainable adoption. The dissertation proposal is divided into three topics all with a common theme: Using LCA and TEA to assess the sustainability of, and advance, agricultural systems. A drought tolerant crop currently grown in India, guar, was investigated to understand relative environmental impact and economic viability in the American Southwest compared to existing crops. Guar is cultivated as a source of guar gum, used primarily in hydraulic fracking fluid for shale oil and gas recovery, with demand currently met through importation. Therefore, a feasibility analysis was performed for a domestic guar supply in Arizona and New Mexico using LCA and TEA. The integrated assessment provided insight on environmental and economic performance of guar for comparison to existing crops. Results indicate that environmentally, guar has lower GHGs than many crops currently cultivated in the American Southwest. Economically, guar gum can be produced for less than the five-year average U.S. import price, with minimizing or eliminating irrigation identified as a critical area for further research. A best case scenario and sensitivity analysis are also investigated using LCA and TEA to evaluate early-stage development of adopting guar in the American Southwest. LCA is also a valuable assessment tool for emerging agricultural systems. A detailed LCA was performed for a first-of-its-kind study investigating the GHGs of commercial indoor cannabis cultivation. Since legalization, the cannabis industry has seen substantial growth with many products being cultivated inside industrialized warehouses. An engineering process model was built to track material and energy requirements of a typical indoor cannabis facility which was then translated to GHGs using LCA methodology. Results of a U.S.-wide analysis indicate that indoor cannabis production leads to substantial GHGs regardless of where it is cultivated, with regions such as the Mountain West and Midwestern United States being much more GHG intensive than East or West Coasts. Individual processes that lead to the majority of GHGs are heating, ventilation, and air conditioning (HVAC), high intensity grow lights and the addition of carbon dioxide for increased plant growth rates. Results of this work have informed the industry, consumers, and policymakers of the environmental impact from this practice while providing insight on ways to reduce GHG emissions. Despite LCA and TEA being proven methodologies for assessing novel, emerging and established processes and products, limitations do exist. Particularly, in the context of agriculture, LCA does not traditionally account for water use outside of the emissions associated with procurement and use. In the American Southwest specifically, it is critical to understand water use and associated environmental impact to make informed decisions regarding ecosystem and societal sustainability. Recently, the development of an advanced LCA method, water scarcity footprint (WSF), has enhanced that ability to understand spatial and temporal considerations of freshwater consumption. However, this method is actively emerging and therefore limitations exist, particularly for arid regions where water demand is typically higher than the amount of water available. A novel method was proposed that can improve resolution and decision-making capabilities for freshwater environmental impact when evaluating arid regions. Results include method comparisons that highlight the improved resolution between the developed method and the traditional WSF method. Furthermore, a case study shows variation of the two methods when applied to alfalfa production in the American Southwest that reveals the severity of drought in the region. The proposed method enables improved resolution when considering spatial and temporal freshwater use in arid regions which enhances decision-making capabilities for product development. Throughout this work, traditional and advanced sustainability metrics, LCA, TEA and WSF, were used to understanding the environmental impact and economic viability of various agricultural-related products. Results from these assessments, from novel and existing technology investigation, provide quantifiable results for holistic comparisons and internal process improvement. These results can serve as decision-making tools during the research and development and commercialization stages, all leading toward providing a more sustainable future.Item Open Access Inflammatory effects of cook stove emissions on cultured human bronchial epithelial cells(Colorado State University. Libraries, 2010) Hawley, Brie, author; Volckens, John, advisor; Willson, Bryan, committee member; Reynolds, Stephen J., committee memberApproximately half the world's population uses biomass as a fuel for cooking and heating. This form of combustion is typically achieved by burning wood in a primitive indoor cook stove. Human exposure to combustion byproducts emitted from these 'traditional' stoves is an important global health concern. Such exposures cause an estimated two million premature deaths each year and have been associated with increased incidence of pulmonary disease, eyesight degradation, cancer, and adverse pregnancy outcomes. Many types of 'improved cook stoves' have been developed over the past few decades to address this concern. The aim of this research was to compare the effects of traditional and improved cook stove emissions on normal human bronchial epithelial cells exposed to a single biomass combustion event. We used a direct, aerosolto-cell deposition system to expose cell cultures to cook stove emissions. We then quantified the relative expression of three different mRNA transcripts associated with a cellular inflammation at 1 and 24 hours following exposure. We hypothesized that cultured human bronchial epithelial cells exposed to wood smoke from an improved cook stove would produce lower levels of inflammatory transcripts as compared to cells exposed to emissions from a traditional stove. Wood smoke was generated from three stove types: an energy efficient model designed and distributed by Envirofit International, an energy efficient model designed and distributed by Philips Inc., and a traditional three stone fire. The emissions from each cook stove were substantially different, with the three stone fire having the highest emissions of particle number, particle size, and particle mass. Cellular expression of inflammatory genes was also significantly higher in exposed vs. control cells, with the three stone fire having the greatest effect. These results provide preliminary evidence that improved cook stoves have the potential to improve human health.Item Open Access Innovative hydrogen station operation strategies to increase availability and decrease cost(Colorado State University. Libraries, 2019) Kurtz, Jennifer, author; Bradley, Thomas, advisor; Willson, Bryan, committee member; Suryanarayanan, Siddharth, committee member; Ozbek, Mehmet, committee memberMajor industry, government, and academic teams have recently published visions and objectives for widespread use of hydrogen in order to enable international energy sector goals such as sustainability, affordability, reliability, and security. Many of these visions emphasize the important and highly-scalable use of hydrogen in fuel cell electric cars, trucks, and buses, supported by public hydrogen stations. The hydrogen station is a complicated system composed of various storage, compression, and dispensing sub-systems, with the hydrogen either being delivered via truck or produced on-site. As the number of fuel cell electric vehicles (FCEVs) on roads in the U.S. have increased quickly, the number of hydrogen stations, the amount of hydrogen dispensed, and the importance of their reliability and availability to FCEV drivers has also increased. For example, in California, U.S., the number of public, retail hydrogen stations increased from zero to more than 30 in less than 2 years, and the annual hydrogen dispensed increased from 27,400 kg in 2015 to nearly 105,000 kg in 2016, and more than 913,000 kg in 2018, an increase of nearly 9 times in 2 years for retail stations. So, although government, industry, and academia have studied many aspects of hydrogen infrastructure, much of the published literature does not address hydrogen station operational and system innovations even though FCEV and hydrogen stations have some documented problems with reliability, costs, and maintenance in this early commercialization phase. In general, hydrogen station research and development has lagged behind the intensive development effort that has been allocated to hydrogen FCEVs. Based on this understanding of the field, this research aims to identify whether integrating reliability engineering analysis methods with extensive hydrogen station operation and maintenance datasets can address the key challenge of station reliability and availability. The research includes the investigation and modeling of real-world hydrogen station operation and maintenance. This research first documents and analyzes an extensive dataset of hydrogen station operations to discover the state-of-the-art of current hydrogen station capabilities, and to identify performance gaps with key criteria like cost, reliability, and safety. Secondly, this research presents a method for predicting future hydrogen demand in order to understand the impact of the proposed station operation strategies on data-driven decision-making for low-impact maintenance scheduling, and optimized control strategies. Finally, based on an analysis indicating the need for improved hydrogen station reliability, the research applies reliability engineering principles to the hydrogen station application through development and evaluation of a prognostic health management system.Item Open Access Model-based systems engineering application to data management for integrated sustainable human settlement modeling(Colorado State University. Libraries, 2024) Adjahossou, Anicet, author; Grigg, Neil, advisor; Bradley, Thomas, committee member; Conrad, Steven, committee member; Willson, Bryan, committee member; Fremstad, Anders, committee memberThe challenges associated with the transition from current approaches to temporary humanitarian settlement to integrated, sustainable human settlements is largely due to a significant increase in the number of forcibly displaced people over the last few decades, the difficulties of sustainably providing the needed services to the required standards, and the prolongation of emergencies. According to the United Nations High Commissioner for Refugees (UNHCR)'s Global Appeal 2023, more than 117.2 million people were forcibly displaced or stateless in 2023, representing a little over 1% of the world's population. The average lifespan of a humanitarian settlement is between 17 and 26 years (UNHCR), and factors such as urban growth and adverse environmental changes have exacerbated the scale of the difficulties. Despite these problematical contexts, short-term considerations continue to guide the planning and management of humanitarian settlements, to the detriment of more integrated, longer-term perspectives. These factors call for a paradigm shift in approach to ensure greater sustainability right from the planning phases. Recent studies often attribute the unsustainability of humanitarian settlements to poor design and inadequate provision of basic resources and services, including water, energy, housing, employment and economic opportunities, among others. They also highlight apparent bottlenecks that hinder access to meaningful and timely data and information that stakeholders need for planning and remediation. More often than not, humanitarian operations rely on ad hoc methods, employing parallel, fragmented and disconnected data processing frameworks, resulting in the collection of a wide range of data without subsequent analysis or prioritization to optimize potential interconnections that can improve sustainability and performance. Furthermore, little effort has been made to investigate the trade-offs involved. As a result, major shortcomings emerged along the way, leading to disruption, budget overruns, disorder and more, against a backdrop of steadily declining funding for humanitarian aid. However, some attempts have been made to move towards more sustainable design approaches, but these have mainly focused on vague, sector-specific themes, ignoring systemic and integrative principles. This research is a contribution to filling these gaps by developing more practical and effective solutions, based on an integrated systemic vision of a human settlement, defined and conceptualized as a complex system. As part of this process, this research proposes a model-driven methodology, supported by Model-Based Systems Engineering (MBSE) and a Systems Modeling Language (SysML), to develop an integrated human settlement system model, which has been functionally and operationally executed using Systems Engineering (SE) approach. This novel system model enables all essential sub-systems to operate within the single system, and focuses on efficient data processing. The ultimate aim is to provide a global solution to the interconnection and integration challenges encountered in the processing of operational data and information, to ensure an effective transition to sustainable human settlements. With regard to the interconnectedness between the different sectors of the sub-systems, this research proposes a Triple Nexus Framework (TNF) in an attempt to integrate water, energy and housing sector data derived from one sub-system within the single system by applying systems engineering methods. Systems engineering, based on an understanding of the synergies between water, energy and housing, characterizes the triple nexus framework and identifies opportunities to improve decision-making steps and processes that integrate and enhance quality of data processing. To test and validate the performance of the system model, two scenarios are executed to illustrate how an integrated data platform enables easy access to meaningful data as a starting point for modeling an integrated system of sustainable human settlement in humanitarian contexts. With regard to framework performance, the model is simulated using a megadata nexus, as specified by the system requirement. The optimization simulation yields 67% satisfactory results which is further confirmed from a set of surveyed practitioners. These results show that an integrated system can improve the sustainability of human settlements beyond a sufficiently acceptable threshold, and that capacity building in service delivery is beneficial and necessary. The focus on comprehensive data processing through systems integration can be a powerful tool for overcoming gaps and challenges in humanitarian operations. Structured interviews with question analysis are conducted to validate the proposed model and framework. The results prove a consensus that the novel system model advances the state of the art in the current approach to the design and management of human settlements. An operational roadmap with substantial programmatic and technical activities required to implement the triple nexus framework is recommended for adoption and scaling-up. Finally, to assess the sustainability, adaptability and applicability of the system, the proposed system model is further validated using a context-based case study, through a capacity assessment of an existing humanitarian settlement. The sustainability analysis uses cross-impact matrix multiplication applied to classification (MICMAC) methodologies, and results show that the development of the settlement are unstable and therefore unsustainable, since there is no apparent difference between influential and dependent data. This research tackles an important global challenge, providing valuable insights towards sustainable solutions for displaced populations, aligning with the United Nations 2030 Agenda for Sustainable Development.Item Open Access Sustainability tradeoffs within photoautotrophic cultivation systems: integrating physical and lifecycle modeling for design and optimization(Colorado State University. Libraries, 2018) Quiroz-Arita, Carlos Enrique, author; Bradley, Thomas H., advisor; Bark, David, committee member; Blaylock, Myra, committee member; Marchese, Anthony, committee member; Sharvelle, Sybil, committee member; Willson, Bryan, committee memberPhotoautotroph-based biofuels are considered one of the most promising renewable resources to meet the global energy requirements for transportation systems. Long-term research and development has resulted in demonstrations of microalgae areal oil productivities that are higher than crop-based biofuels, about 10 times that of palm oil and about 130 times that of soybean. Cyanobacteria is reported to have ~4 times the areal productivity of microalgae on an equivalent energy basis. Downstream of this cultivation process, the cyanobacteria biomass and bioproducts can be supplied to biorefineries producing feed, biomaterials, biosynthetic chemicals, and biofuels. As such, cyanobacteria, and microalgae-based systems can be a significant contributor to more sustainable energy and production systems. This research presents novel means to be able to analyze, integrate, assess, and design sustainable photoautotrophic biofuel and bioproduct systems, as defined using lifecycle assessment methods (LCA). As part of a broad collaboration between industry, academia, and the national laboratories, I have developed models and experiments to quantify tradeoffs among the scalability, sustainability, and technical feasibility of cyanobacteria biorefineries and microalgae cultivation systems. A central hypothesis to this research is that the lifecycle energy costs and benefits, the cultivation productivity, and the scalability of any given organism or technology is governed by the fluid mechanics of the photobioreactor systems. The fluid characteristics of both open raceway ponds and flat photobioreactors, are characterized through industrial-scale experiment and modeling. Turbulent mixing is studied by applying Acoustic Doppler Velocimetry (ADV), Particle Image Velocimetry (PIV), and computational fluid dynamics (CFD) characterization tools. The implications of these fluid conditions on photoautotrophic organisms are studied through cultivation and modeling of the cyanobacteria, Synechocystis sp. PCC6803. Growth-stage models of this cyanobacteria include functions dependent on incident radiation, temperature, nutrient availability, dark and photo-respiration. By developing an integrated approach to laboratory experimentation and industrial-scale growth experiments, we have validated models to quantify the scalability and sustainability of these novel biosystems. These capabilities are utilized to perform long-term and industrially-relevant assessments of the costs and benefits of these promising technologies, and will serve to inform the biological engineering research and development of new organisms.Item Open Access Techno-economic analysis of ash removal in algal biomass(Colorado State University. Libraries, 2018) Hess, Derek E., author; Quinn, Jason, advisor; Willson, Bryan, committee member; Peebles, Christie, committee memberLarge-scale microalgae cultivation for biodiesel production is expected to be performed utilizing open air growth infrastructure which will inherently introduce ash into the system. High ash content biomass represents a significant challenge for the production of biofuel as it increases processing capital and operational costs. This study directly assesses the economic viability of pretreatment processes focused on the removal of ash from biomass grown with an algal turf scrubber (ATS) unit. An engineering process model of biofuel production was developed based on an ATS growth architecture followed by an ash removal process and conversion of the biomass to fuels through hydrothermal liquefaction. The model was validated with literature for the growth and conversion processes and validated with experimental data for the de-ashing process. A total of 14 different scenarios were investigated based on two different ash removal techniques, water wash and alkaline extraction treatment operated at various temperatures and alkaline levels. The engineering process model was integrated with techno-economic modeling to investigate the impact of ash on the required biomass and fuel selling price for economic viability. Capital costs associated with the conversion of biomass to biofuel were found to double as ash content increased from 0% to 70%, correlating to a 21% increase in fuel selling price. Integrating an ash removal step resulted in reduced conversion capital costs. However, only the water wash at 25°C scenario was found to reduce the overall fuel selling price. Operational expenses associated with required waste water treatment, chemical cost associated with the alkaline extraction de-ashing technology, and heating of the microalgae slurry during the de-ashing process were found to significantly increase the overall fuel selling price of the microalgae biofuel.