The United States Army is currently undergoing an initiative to modernize its installations and vehicles to reduce logistical demand, mitigate the effects of climate change, and improve the resilience of Army infrastructure. Published in 2022, the Army Climate Strategy (ACS) [1] provides a timeline for the widespread electrification of both tactical and non-tactical vehicle fleets throughout the next thirty years. The implementation of electric vehicles (EVs) in Army tactical and non-tactical operations requires proactive design solutions for energy and logistics systems to maintain capabilities and responsibly manage costs through this transition. This paper responds to three questions that arise in this modernization process. First, a framework for prioritization of which vehicles to replace with EVs is developed by inspecting lifecycle cost and carbon footprint. Second, a simulation tool is developed to suggest the number, type, and location of chargers to support the non-tactical EV fleet on an Army installation. Finally, energy production and conversion pathways are inspected for their viability, cost, and carbon footprint to identify the most advantageous paradigms for fueling tactical vehicles. The summative response to these three topics expands the base of knowledge informing Army vehicle infrastructure modernization.

Additive manufacturing (AM) techniques are expanding what is possible for designing and constructing gas turbine components that can handle increasingly harsh operating conditions. However, AM techniques can also introduce surface roughness that is more prominent than conventional manufacturing methods. The influence of this roughness could have an important effect on the performance of film cooling holes. However, little is known experimentally on what happens inside of a film cooling hole since this region is challenging to access with traditional measurement techniques. This study uses magnetic resonance velocimetry (MRV) to observe the in-hole flow structure of a scaled version of a baseline diffuser-shaped hole configuration with and without surface roughness at two blowing ratio conditions. The roughness geometry is derived from computed tomography (CT) scans of a metal-AM diffuser hole. The three-component, three-dimensional, time-averaged velocity field is measured by MRV and includes the flow from the plenum, within the hole, and in the vicinity of the hole exit. The momentum distribution within the diffuser differs between the smooth and rough holes, with peak velocities and flow asymmetry influenced by the surface roughness. Flow along the leeward wall of the diffuser is nearly separated, and the size of this separated flow region is smaller in the roughened cases. These effects are accentuated at larger blowing ratio. These data provide explanatory evidence of how the momentum distribution within smooth and rough holes may impact surface effectiveness results downstream of the shaped holes. CT scans of the surface roughness coupled with the MRV measurements provide non-optical means to characterize the hole geometry and as-built performance of additively manufactured test coupons with important implications for the field.

The General Services Administration (GSA) owns and maintains the largest portfolio of facilities in the United States. This infrastructure stock requires significant resources to operate, including ample, reliable access to electricity, natural gas, and water. The Department of Civil and Mechanical Engineering at the United States Military Academy has partnered with the GSA to study the opportunity to better integrate building assets with local energy infrastructure. The project is part of the GSA’s Grid-Interactive Efficient Buildings (GEB) program and is focused on the Central Islip Federal Courthouse complex. Using a case-study approach, the project explores the capability for the courthouse to improve how energy is produced and consumed with the goals of reducing operating expenses, improving environmental impacts, and integrating more intelligently with the local grid. A technoeconomic model was built and a sensitivity analysis completed to consider the tradeoffs of conceptual design alternatives, including solar photovoltaics and energy storage. The solutions presented are placed in context with the broader literature on GEB to support the future of energy infrastructure. The findings of the project show that a carport style photovoltaic array in an existing parking lot at the courthouse has an estimated payback period of 19 years, while the best ground mounted array has a payback of eight years, albeit a lower generation capacity compared with the larger carport array.

This work reports the results of paired experiments for the aft section of a complex internal cooling flow within a gas turbine vane using Magnetic Resonance Velocimetry (MRV) and steady-state Infrared (IR) thermography. The aft cooling insert for the vane with two-pass impingement was designed at a scale five times larger than the original and built using stereolithography (SLA) fabrication methods. The MRV technique was used to measure the three-dimensional, three-component velocity field for a test case with a Reynolds number range of 2,600 to 7,600 based on diameter of the impingement holes. Flow distribu-tion, impingement hole performance, and cross flow effects are discussed for the experiment in which a dilute aqueous copper sulfate solution was used as the working fluid. A paired experiment with a geo-metrically similar design employed electrical heating of a thin stainless steel shim to model a constant heat flux boundary condition of an interior wall of the turbine vane. The modeled vane insert was then operated with air as the working fluid at two test conditions with Reynolds numbers in the range of approximately 1,200 to 7,600 based on the diameter of the impingement holes. An IR camera was used to measure the surface temperature of the shim. Using energy balances and the known heat flux, the temperature data were used to determine heat transfer characteristics of the impinging jets for the pres -sure and suction side surfaces, including the Nusselt number. The MRV and IR data sets provide detailed insight into the surface effects of the flow distribution and the result on the local and area-averaged heat transfer performance. A strong coupling between the velocity field and temperature data provide insight into design feature performance, and serve as a validation data set for matched computational simulations. Finally, a comparison with internal heat transfer correlations is presented using the data from Florschuetz et al. [1]. The results showed a lack of agreement with Florschuetz, leading to the de-velopment of a novel methodology for estimating the heat transfer performance of an impinging hole with crossflow. Measurement uncertainty was estimated to be +/- 5% for velocity and +/- 5% for the spatially averaged Nusselt number distributions. Published by Elsevier Ltd.

In recent years, the United States Army has increasingly pushed to reduce carbon dioxide emissions across all installations and operations. This push is part of a broader effort to increase the sustainability and resilience of critical defense assets, by allowing them to operate for longer periods of time, with lower environmental impacts, lower costs, and increased mission readiness. One proposed solution to help reduce the emissions of Army installations is to replace conventional internal combustion engine vehicles with fully electrified vehicles. In particular, the non-tactical vehicle fleet is of primary interest to be rapidly converted to electrified drivetrains. The primary purpose of this work is to assess whether fully electrified vehicles have the lowest life-cycle emissions when considering the specific mission requirements and infrastructure present at Army installations. This work uses lifecycle analysis methods to compare the carbon emissions for vehicles with different drivetrains, located in different electric grid regions across the United States, while driving different distances to achieve the necessary missions of their operators. These variations in how the vehicles are designed, charged, and used showcases that, while electric vehicles are the best for many scenarios, they are not always the correct choice to maximize the total reduction in carbon emissions associated with transportation services at Army installations.

Variable, renewable energy (VRE) generation such as solar power has seen a rapid increase in usage over the past decades. These power generation sources offer benefits due to their low marginal costs and reduced emissions. However, VRE assets are not dispatchable, which can result in a mismatch of the electric supply and demand curves. Pumped-storage hydropower (PSH) seeks to solve this by pumping water uphill during times of excess energy production and releasing the water back downhill through turbines during energy shortages, thus serving as a rechargeable battery. Creating new PSH systems, however, requires a large amount of capital and suitable locations. The United States Army Corps. of Engineers (USACE) is the largest producer of hydroelectric power within the United States, and as such, may have favorable sites for the addition of PSH. This study seeks to develop a method for evaluating these existing hydroelectric facilities using techno-economic methods to assess the potential for adding PSH. Each USACE facility was evaluated based on site specific characteristics from previously unpublished data to estimate the power generation and energy storage potential. The temporal nature of local wholesale electricity prices was accounted for to help estimate the financial feasibility of varying locations. Sensitivity analysis was performed to highlight how the method would identify the viability of facilities with different operational conditions. The methodologies detailed in this study will inform decision-making processes, and help enable a sustainable electric grid.

Reliable performance of energy and water infrastructure is central to the mission readiness of the United States Army. These systems are vulnerable to coordinated attacks from an adversary as well as disruption from natural events. The objectives of this work were to investigate Army installations in North America, identify best practices for improving the resilience and sustainability of critical energy and water infrastructure, and develop a framework and methodology for analyzing the resilience of an installation under varying outage scenarios. This work was accomplished using a multi-layered decision process to identify unique case studies from the 117 active-duty domestic Army installations. A framework for analyzing and assessing the resilience of an installation was then developed to help inform stakeholders. Metered energy and water data from buildings across Fort Benning, GA were curated to inform the modeling framework, including a discrete-event simulation of the supply and demand for energy and water on the installation using ProModel. This simulation was used to study the scale of solutions required to address outage events of varying frequency, duration, and magnitude, the combination of which is described as the severity of outages at a given site. This project helps develop a framework to inform how installations might meet Army Directive 2020-03, which states that installations must be able to sustain mission requirements for a minimum of 14 days after a disruption has occurred.

Heat transfer performance of a single cylindrical orthogonal jet impinging on a flat plate was obtained through steady-state infrared (IR) thermometry. One Reynolds (Re) number of 23,000 based on pipe exit diameter was considered. The distance of the jet exit plane from the shim varied from two to ten times the impingement jet diameter in increments of two diameters. The observed temperature and constant heat flux boundary condition allowed for the calculation of a Nusselt (Nu) number distribution to estimate the heat transfer performance of the impingement jet. At the smallest separation distance of two diameters, the relative maximum heat transfer performance is found at the stagnation point followed by a second peak occurring at a radial distance of approximately two diameters from the stagnation point. Compared to all jet exit separation distances studied, the distance of six diameters exhibited the greatest magnitude Nusselt number at the stagnation point. A paired fluids experiment using Magnetic Resonance Velocimetry (MRV) techniques collected hydrodynamic data of a single impinging jet at a matching Re number of 23,000 and jet exit plane distances. This work provides relevant data for correlation of impingement cooling design through unique analysis of the fluid mechanics and heat transfer characteristics of a single impinging jet. Measurement uncertainty was assessed to range from +/−1% to +/−10% for Nusselt number and +/−7% for velocity.

The development of advanced small caliber weapon systems has resulted in rounds with more material penetration capabilities. The increased capabilities may mean that existing live-fire facilities will no longer be adequate for the training and certification of military and law enforcement personnel. Constraints on training in many live-fire shoot house facilities are already in place, with some allowing only single round impact during training. With little understanding of the probability of perforation, or failure, of existing containment systems, this study evaluates risk by studying the single round impact of small caliber ammunition against live-fire shoot house containment systems constructed from AR500 steel panels with two-inch ballistic rubber covering. An analytical and numerical study was conducted using an existing model for steel penetration developed by Alekseevskii-Tate and the EPIC finite element code. A modified form of the advancing cavity model for the ballistic resistance of the target material was used to account for the relatively unconfined material resulting from the studied impacts. These results are then compared to experimental tests conducted by Goodman for rounds of various small calibers impacting live-fire facility containment systems. Projectile and target characteristics were then modeled as continuous random variables, and Monte Carlo simulations were conducted using the validated analytical model to estimate the probability of a single round impact perforating the live-fire facility containment system. An importance sampling scheme was used to reduce the variance of the solution and provide a more accurate estimate of the probability of failure. The Alekseevskii-Tate model was found to provide accurate estimates of the depth of penetration when compared to experimental and numerical results at ordnance velocities and an estimate of the probability of failure is on the order of 1x10 -5 . This study provides useful tools for the analysis of existing live-fire facilities against future and existing ammunition, and for the design of new facilities. When coupled with Monte Carlo simulation techniques, a risk-based approach to certify live-fire facilities for use with any variety of small arms ammunition can be applied.

This work reports the results of paired experiments for a complex internal cooling flow within a gas turbine vane using Magnetic Resonance Velocimetry (MRV) and steady-state Infrared (IR) thermometry. A scaled model of the leading edge insert for a gas turbine vane with multi-pass impingement was designed, built using stereolithography (SLA) fabrication methods, and tested using MRV techniques to collect a three-dimensional, three-component velocity field data set for a fully turbulent test case. Stagnation and recirculation zones were identified and assessed in terms of impact on potential cooling performance. A paired experiment employed an IR camera to measure the temperature profile data of a thin, heated stainless steel impingement surface modeling the inside turbine blade wall cooled by the impingement from the vane cooling insert, providing complementary data sets. The temperature data allow for the calculation of wall heat transfer characteristics, including the Nusselt number distribution for cooling performance analysis to inform design and validate computational models. Quantitative and qualitative comparisons of the paired results show that the flow velocity and cooling performance are highly coupled. Module-to-module variation in the surface Nusselt number distributions are evident, attributable to the complex interaction between transverse and impinging flows within the apparatus. Finally, a comparison with internal heat transfer correlations is conducted using the data from Florschuetz [1]. Measurement uncertainty was assessed and estimated to be approximately +7% for velocity and ranging from +3% to +10% for Nusselt number.

This work shares a model that was developed to compare the energy requirements of meal-kit delivery systems to conventional grocery shopping. Meal-kit services can reduce food waste because the kits pre-portion ingredients for each recipe, thereby saving energy. However, the supply chain and packaging requirements of meal-kit delivery are different than those for grocery stores, potentially offsetting any energetic benefits of reduced food waste. If meal-kit delivery replaces some trips to the grocery store, then transportation-related savings might be significant. The tradeoffs of these competing effects are non-obvious, so mass and energy balances were used to assess embedded energy in both pathways. The model was illustrated under representative operating conditions for a consumer in Austin, Texas using Monte Carlo simulation. Both per-meal and per-week, a meal-kit delivery service meal is more energy intensive than procuring the same meal from conventional grocery stores primarily due to single-use packaging. Consumer transportation to the grocery store was also found to be particularly energy intensive. These results suggest that the energetic requirements of meal-kit delivery services could be reduced such that they are less than conventional grocery shopping if reusable or low-impact packaging is used, and if the delivery services are able to reduce the number of weekly trips to the grocery store.2

Wind and solar energy can potentially be used to power desalination facilities to sustainably meet growing water demands with a smaller carbon footprint than conventional approaches. This work presents a detailed method for assessing the technical and economic viability of using these renewable forms of energy to power desalination facilities. The method relies on a multi-layered, spatial model that incorporated multiple variables such as depth of water resource, salinity levels, magnitude of local renewable energy resources, distance to water infrastructure, and, for comparative purposes, the local price of water. To illustrate this method, it was applied to 1445 site locations on state of Texas lands owned by the General Land Office that overlay brackish aquifer resources. Using this method, 193 potentially economically viable sites were identified that have estimated renewable desalination water production costs lower than local municipal water prices. The results of this analysis showed that using wind to power a desalination facility is economically preferable at 145 of the 193 sites; solar was preferable at the remaining 48 sites. Solar and wind resources are both abundant in Texas; however, the particularly high capacity factors for wind across much of the state helps wind deliver the lowest cost electricity.

Hydrogen as an energy carrier allows the decarbonization of transport, industry, and space heating as well as storage for intermittent renewable energy. The objective of this paper is to assess the future engineering potential for hydrogen and provide insight to areas of research to help lower economic barriers for hydrogen adoption. This assessment was accomplished by creating top-level system models based on energy requirements for end-use services. Those models were used to investigate four case studies that provide a global view augmented with specific national examples. The first case study assesses the potential penetration of hydrogen using a global energy system model. The second applies the dynamic integrated climate–ecosystem–economics model to derive an estimate of the impact of the diffusion of hydrogen as an energy carrier. The third determines the required growth in renewable power and water usage to power transportation in the United States (US) with hydrogen. The fourth assesses the use of hydrogen for heating in the United Kingdom (UK). In all cases, there appeared to be significant potential for hydrogen adoption and net energetic benefit. Globally, hydrogen has the potential to account for approximately 3% of energy consumption by 2050. In the US, using hydrogen for on-road transportation could enable a reduction in rejected energy of nearly 10%. Also, hydrogen might provide the least cost alternative to decarbonizing space heating in the UK. The research highlights a challenge raised by widespread abandonment of nuclear power. It is currently unclear what the removal of nuclear would do to the cost of energy as nations attempt to limit global greenhouse gas emissions. Nuclear power has also been proposed as a source for large scale production of hydrogen. Finally, this analysis shows that with today's technological maturity making the transition to a hydrogen economy would incur significant costs.

Water is essential to human health and economic development due to its utilization in sanitation, agriculture, and energy. Supplying water to an expanding world population requires simultaneous consideration of multiple societal sectors competing for limited resources. Water conservation, supply augmentation, distribution, and treatment of contaminants must work in concert to ensure water sustainability. Water is linked to other sectors, and the quantity and quality of water resources are changing. The efficient use of water in agriculture, the largest user of water worldwide, via drip irrigation is described as is the use of energy-intensive reverse osmosis to supplement freshwater supplies. Efforts to manage watersheds and model their responses to severe weather events are discussed along with efforts to improve the predictability of their function. The regional competition for water resources impacts both energy and water supply reliability, which requires that nations balance both for sustainable economic development. The use of water and energy in the US is described which provides a lens through which to both rethink the interrelationship of water and energy as well as evaluate technological developments. Advances in nanotechnology are highlighted as one emerging technology. These results underscore the multifaceted nature of water sustainability, its interrelationship to energy and economic development, and the need to develop, manage and regulate water systems in a concerted manner.

Energy storage technologies can enable nuclear power plants to follow electricity demand throughout the day and minimize cycling costs. Several dynamic performance requirements and heuristics (such as cost and environmental impact) are presented in this chapter to compare energy storage technologies that could be integrated with nuclear power. These characteristics are compared to suggest potential energy storage integration options for Plant Vogtle units 3 and 4, two pressurized-water nuclear reactors being built in the United States. This chapter suggests that thermal energy storage technologies such as hot and cold water storage might be the most favorable for integration with a nuclear power plant due to their low cost and limited environmental impact.

This work developed two methods to investigate the technical and economic potential of hydrogen demand and production: (1) estimating potential hydrogen demand for light-duty vehicles (LDVs) at the county-level using a first-order engineering model, and (2) quantifying temporal renewable hydrogen production from wind energy using a linear programming model. The potential hydrogen demand was primarily evaluated for three geographical regions: (1) the United States, (2) Texas, and (3) the Texas Triangle which is one of the nation's most important mega-regions. The linear programming model compared marginal electricity and hydrogen prices to maximize revenue over the course of a year. The analysis primarily focused on the Electric Reliability Council of Texas (ERCOT), but also included other six U.S. electricity markets for hypothetical analysis. Results show that the potential hydrogen demand for LDVs in the United States, Texas, and the Texas Triangle are 53.3, 5.3, and 3.9 billion kg per year, respectively. Using the electrolyzer system energy efficiency of 75% and the marginal hydrogen price of $4/kg, the wind energy in Texas as of 2015 could produce nearly 0.84 billion kg of hydrogen, which could supply about 22% of the potential hydrogen demand for LDVs in the Texas Triangle. When the marginal hydrogen price is low (e.g. $1/kg), it is only favorable to produce hydrogen during early morning hours, especially, 1-6 a.m., in ERGOT and other electricity markets except California's market. These results could provide information for decision makers to better understand the holistic feasibility of a hydrogen economy in the United States.

This paper assesses the environmental impacts of the average American's diet and food loss and waste (FLW) habits through an analysis of energy, water, land, and fertilizer requirements (inputs) and greenhouse gas (GHG) emissions (outputs). We synthesized existing datasets to determine the ramifications of the typical American adult's food habits, as well as the environmental impact associated with shifting diets to meet the US Department of Agriculture (USDA) dietary guideline recommendations. In 2010, FLW accounted for 35% of energy use, 34% of blue water use, 34% of GHG emissions, 31% of land use, and 35% of fertilizer use related to an individual's food-related resource consumption, i.e. their foodprint. A shift in consumption towards a healthier diet, combined with meeting the USDA and Environmental Protection Agency's 2030 food loss and waste reduction goal could increase per capita food related energy use 12%, decrease blue water consumption 4%, decrease green water use 23%, decrease GHG emissions from food production 11%, decrease GHG emissions from landfills 20%, decrease land use 32%, and increase fertilizer use 12%.

In this study, we compile and curate data from 2012, 2013, and 2014 on flared gas and generated wastewater associated with hydraulic fracturing operations in seven major shale regions of the USA. In the process, we provide an historical perspective of the management practices of flared gas and wastewater prior to the decline in oil prices in 2015. An engineering assessment of the technical potential for repurposing the energy from flared gas for treating hydraulic fracturing wastewater is also considered.

Hydrocarbon fuel production and utilization are considered water intensive processes due to the high volumes of water used in source development and fuel processing. At the same time, there is significant water formed during combustion. However, this water is not currently widely harvested at the site of production. Instead, it is added to the hydrologic cycle, often in a different location from the fuel production site. This study quantifies the water formed from combustion of these fuels and analyzes the magnitudes of formation in the context of other hydrologic sources and sinks in order to facilitate future assessments of water harvesting technology and/or atmospheric impacts of combustion. Annual water formation from stoichiometric combustion of hydrocarbon fuels, including natural gas, oil- and natural gas liquid-derived products, and coal, in the United States and worldwide are presented and compared with quantities of water sequestered, evaporated, and stored in the atmosphere. Water production factors in terms of mass and energy of fuel consumed, WPFm and WPFe, respectively, are defined for the comparison of fuels and incorporation into future life cycle analyses (LCAs). Results show that water formation from combustion has increased worldwide from 2005 to 2015, with the largest increase coming from growth in combustion of natural gas. Water formation from combustion of hydrocarbon fuels equals or exceeds water sequestered from the hydrologic cycle through deep well injection in the US annually. Overall, water formation is deemed significant enough to warrant consideration by LCAs of water intensity in fuel production and use, and should be included in future analyses.