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3rd International Conference of Energy Harvesting, Storage, and Transfer (EHST'19) ; Many military systems produce thermal energy as a by-product. Generally, this so-called waste heat is lost to the surroundings. Capturing the waste heat and putting it to beneficial use could increase the efficiency of military systems, while having the added benefit of reducing thermal signatures. This paper outlines the application of modeling and simulation to estimate the usable electric power produced by a thermoelectric generator (TEG) array on the exhaust muffler of a small fossil fuel generator. The simulation results informed design, construction, and testing of an initial prototype. Key prototype test variables were temperature difference, load resistance, and electric current. The results of the experiment were compared to and used to update the initial model. This small-scale effort provides initial insight into the efficacy of applying thermoelectric generators to military systems. Future work will explore larger arrays, as well as detailed investigation of the tradespace to identify promising equipment or applications, and inform capability and acquisitions requirements. ; NEPTUNE program funded and scoped this research

IAPE '19, Oxford, United Kingdom ; Modeling and simulation are key concepts in systems engineering and system design. They allow the engineer to use fewer resources to establish a sound design before fully committing to building a full prototype. Using this concept, this paper goes through the modeling process for the application of thermoelectric generators (TEGs) in an array. Systems could benefit off using this passive thermal recovery device by converting that thermal energy into electricity. For military systems, this is beneficial as there are many initiatives in the United States military to reduce their reliance on fossil fuels by making current systems more efficient or converting to systems that do not use fossil fuels. Applying TEGs to these particular systems would help with this inititative and possibly have an intrinsic benefit of reducing a system's thermal signature, which could be a topic of future work. Designing the models and simulation for this application needs to be basic and simple before creating complex models for final design. The types of models built and discussed in this paper will help form the basis of design of an array. These models would help determine the amount of TEGs needed to meet a requirement of the system.

2018 Conference on Systems Engineering Research ; Technological advances in software-defined radios (SDRs), high-speed serial buses, and high-performance computing promise a significant power reduction if adopted for deployed, military wireless communications applications. This paper presents a simple mathematical power consumption model to simulate and quantify the power requirements for two communications architectures in an expeditionary command, control, communications, and computers environment. Analysis and comparison suggest that an enterprise architecture of SDRs operating under ordinary loads could result in a system-wide power reduction of 11% when compared to the currently employed architecture under the same conditions. Depending on usage profiles and equipment mix, the lower and upper bounds for system-wide power reduction by adopting an enterprise architecture were 6% and 31%, respectively. ; Naval Postgraduate School

ASME Power Conference, 2018 ; Military systems greatly depend on the availability of energy. This energy comes mostly in the form of burning fuel in order to produce mechanical work or producing electricity. The ability to extract the most out of these systems aligns with the current focus of energy efficiency, not only in the military, but in society at large. In this research, an infrared camera was used to create an infrared map to infer temperature differences on a gasoline-powered generator at steady state operations. These temperature differences were inputted into an experimental phase during which a digitally-controlled hot plate, water block, variable resistor, and digital acquisitions system were used to measure current output from a single TEG for loads of 1, 10, and 100 ��, respectively. Data were analyzed and the correlation coefficients determined. These coefficients were modeled a single module and then various array configurations for TEGs in COMSOL. Using the findings, a single commercial 56 mm by 56 mm Be2Te3 TEG can yield 0.72 W of power. Simple calculations yield 72 W of power when 100 modules are joined in 10 sets coupled in parallel with each set containing 10 modules in coupled in series. This would require 560 mm by 560 mm or approximately 2 ft. by 2 ft. of system space to be covered.

2018 Conference on Systems Engineering Research ; This paper presents a model-based systems engineering methodology for employing architecture in system analysis (MBSE MEASA) for the cooperation of cross-domain unmanned vehicles conducting humanitarian assistance and disaster relief (HA/DR). The comprehensive framework developed in this paper uses Systems Modeling Language (SysML), which supports the assessment of system requirements for systems engineering. The research develops architecture to analyze collaborative cross-domain unmanned systems performance. The architecture models focus on the interaction between UAVs and UGVs and use the relationship of system architecture products and model-based systems engineering analysis to quantify system performance. This methodology will also identify those design features which are most impactful to mission effectiveness. The MBSE MEASA incorporates the iterative process of systems engineering in determining the optimal solution for the architecture products. This research will demonstrate the usefulness of model-based systems engineering analysis in the design of UAV-UGV cooperation while conducting a mission scenario. The result of this research will be a validated and executable system architecture for cross-domain unmanned vehicle cooperation. The architecture will serve as the conceptual template to guide future research and development of unmanned vehicles.

Military Operations Research Society 86th Symposium ; This paper describes the application of a modified model-based systems engineering methodology for employing architecture in system analysis (MBSE MEASA) to create and validate a cross- domain collaborative autonomous system. Results from the early stages of the MEASA methodology are presented, specifically, the architecture descriptions of Unmanned Air Vehicle (UAV)-Unmanned Ground Vehicle (UGV) team collaboration while conducting humanitarian assistance and disaster relief operations. This study replaces computer-based modeling and simulation inherent to the original MEASA methodology with a field exercise which validated the architecture descriptions. The applied methodology highlights the feasibility of a UAV-UGV team collaboratively conducting structured, rudimentary tasks in a mission scenario. The result of this paper, validated the model for cross-domain unmanned vehicles conducting expeditionary warfare and an analyzed assessment of the system design. This research serves as a model-based systems engineering analysis method for the future development of employing collaborative autonomous systems with military utility.

17 USC 105 interim-entered record; under review. ; The article of record as published may be found at http://dx.doi.org/10.3390/app11094298 ; Military bases perform important national security missions. In order to perform these missions, specific electrical energy loads must have continuous, uninterrupted power even during terrorist attacks, adversary action, natural disasters, and other threats of specific interest to the military. While many global military bases have established microgrids that can maintain base operations and power critical loads during grid disconnect events where outside power is unavailable, many potential threats can cause microgrids to fail and shed critical loads. Nanogrids are of specific interest because they have the potential to protect individual critical loads in the event of microgrid failure. We present a systems engineering methodology that analyzes potential nanogrid configurations to understand which configurations may improve energy resilience and by how much for critical loads from a national security perspective. This then allows targeted deployment of nanogrids within existing microgrid infrastructures. A case study of a small military base with an existing microgrid is presented to demonstrate the potential of the methodology to help base energy managers understand which options are preferable and justify implementing nanogrids to improve energy resilience. ; Naval Postgraduate School

The article of record as published may be found at http://dx.doi.org/10.1002/sys.21559 ; In recent years there has been increased demand for readiness and availability metrics across many industries and especially in national defense to enable data-driven decision making at all levels of planning, maintenance, and operations, and in leveraging integrated models that inform stakeholders of current operational system health and performance metrics. The digital twin (DT) has been identified as a promising approach for deploying these models to fielded systems although several challenges exist in wide adoption and implementation. Two challenges examined in this article are that the nature of DT development is a system-specific endeavor, and the development is usually an additional effort that begins after initial system fielding. A fundamental challenge with DT development, which sets it apart from traditional models, is the DT itself is treated as a separate system, and therefore the physical asset/DT construct becomes a system-of-systems problem. This article explores how objectives in DT development align with those of model-based systems engineering (MBSE), and how the MBSE process can answer questions necessary to define the DT. The key benefits to the approach are leveraging work already being performed during system synthesis and DT development is pushed earlier in a system's lifecycle. This article contributes to the definition and development processes for DTs by proposing a DT development model and path, a method for scoping and defining requirements for a DT, and an approach to integrate DT and system development. An example case study of a Naval unmanned system is presented to illustrate the contributions. ; Naval Postgraduate School ; Identified in text as U.S. Government work. ; This work was supported by Office of Naval Research (ONR)

Military Operations Research Society 86th Symposium ; Solar and wind power generation suffer from intermittency. Consequently, renewable-powered micro-grids often use a traditional electrical grid or an energy storage system to fill the power gaps. Liquid air energy storage (LAES) is a promising method for scalable energy storage. Liquid air energy storage systems (LAESS) combine three mature technologies: cryogenics, expansion turbines, and induction power generation into a system of systems. The resultant behavior of this complex system is difficult to predict through traditional analysis alone. Aspen HYSYS, an industrial process modeling and simulation package, was used to create a model of a building- scale cryogenic system based on a Linde-Hampson cycle. Steady-state cryogenic operations were simulated and model output was validated against a theory-based fundamental comparison. This basic model will be expanded to include power generation. The updated model will then be used to implement a parametric, model-based systems engineering approach to design a LAES system for integration into the renewable-powered micro-grid at the Naval Postgraduate School's turbo- propulsion lab to counter intermittency. This work is part of a larger effort to evaluate the efficacy of potential energy storage solutions for Naval Facilities or Forward Operating Bases (FOB).

17 USC 105 interim-entered record; under temporary embargo. ; The paper presents an organizing framework for directly incorporating United States Department of Defense (DoD) joint operational concepts into early-stage engineering management and system design. It translates operational level guidance from DoD Joint Publications to a concise Operational Mission Architecture Framework (OMAF) that can be used as a starting point for engineering management efforts. The OMAF is used to orient the development of systems architecture products per Department of Defense Architecture Framework (DoDAF) standards. Resultantly, the OMAF serves as a bridging mechanism between the language and terminology employed in the joint operational community and the engineering management community. ; U.S. Government affiliation is unstated in article text.