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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

COSMOLOGICAL SIMULATIONS OF INTERGALACTIC MEDIUM EVOLUTION. I. TEST OF THE SUBGRID CHEMICAL ENRICHMENT MODEL

We present a one-zone galactic chemical enrichment model that takes into account the contribution of stellar winds from massive stars under the effect of rotation, Type II supernovae, hypernovae, stellar winds from low- and intermediate-mass stars, and Type Ia supernovae. This enrichment model will be implemented in a galactic model designed to be used as a subgrid treatment for galaxy evolution and outflow generation in large-scale cosmological simulations, in order to study the evolution of the intergalactic medium. We test our enrichment prescription by comparing its predictions with the metallicity distribution function and the abundance patterns of 14 chemical elements observed in the Milky Way stars. To do so, we combine the effect of many stellar populations created from the star formation history of the Galaxy in the solar neighborhood. For each stellar population, we keep track of its specific mass, initial metallicity, and age. We follow the time evolution of every population in order to respect the time delay between the various stellar phases. Our model is able to reproduce the observed abundances of C, O, Na, Mg, Al, S, and Ca. For Si, Cr, Mn, Ni, Cu, and Zn, the fits are still reasonable, but improvements are needed. We marginally reproduce the nitrogen abundance in very low metallicity stars. Overall, our results are consistent with the predicted abundance ratios seen in previous studies of the enrichment history of the Milky Way. We have demonstrated that our semi-analytic one-zone model, which cannot deal with spatial information such as the metallicity gradient, can nevertheless successfully reproduce the global Galactic enrichment evolution obtained by more complex models, at a fraction of the computational cost. This model is therefore suitable for a subgrid treatment of chemical enrichment in large-scale cosmological simulations.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Revisiting the Effects of Photovoltaic Module Efficiency on Installed System Cost and Market Adoption

We conduct bottom-up analysis of how PV module efficiency could influence residential rooftop installed system costs, using models with improved representation of how soft costs and power electronics are affected by efficiency. We show that the amount of system installed cost savings resulting from high efficiency modules depends on whether or not the system is area-constrained, with much larger savings for the area-constrained case. We then estimate the fraction of physically area-constrained rooftops in the United States to be 61%, with variation between 20% to over 80% of rooftops depending on the state. We find that fraction of area-constrained systems could grow to over 88% by 2050 if building and transportation loads are electrified.

efficiency↗
NASA NTRS1979

Active heat exchange system development for latent heat thermal energy storage

Active heat exchange concepts for use with thermal energy storage systems in the temperature range of 250 C to 350 C, using the heat of fusion of molten salts for storing thermal energy are described. Salt mixtures that freeze and melt in appropriate ranges are identified and are evaluated for physico-chemical, economic, corrosive and safety characteristics. Eight active heat exchange concepts for heat transfer during solidification are conceived and conceptually designed for use with selected storage media. The concepts are analyzed for their scalability, maintenance, safety, technological development and costs. A model for estimating and scaling storage system costs is developed and is used for economic evaluation of salt mixtures and heat exchange concepts for a large scale application. The importance of comparing salts and heat exchange concepts on a total system cost basis, rather than the component cost basis alone, is pointed out. The heat exchange concepts were sized and compared for 6.5 MPa/281 C steam conditions and a 1000 MW(t) heat rate for six hours. A cost sensitivity analysis for other design conditions is also carried out.

Lefrois, R. T.↗
NASA NTRS1988

Cost estimating methods for advanced space systems

Parametric cost estimating methods for space systems in the conceptual design phase are developed. The approach is to identify variables that drive cost such as weight, quantity, development culture, design inheritance, and time. The relationship between weight and cost is examined in detail. A theoretical model of cost is developed and tested statistically against a historical data base of major research and development programs. It is concluded that the technique presented is sound, but that it must be refined in order to produce acceptable cost estimates.

Cyr, Kelley↗
NASA NTRS1989

Markov reliability models for digital flight control systems

The reliability of digital flight control systems can often be accurately predicted using Markov chain models. The cost of numerical solution depends on a model's size and stiffness. Acyclic Markov models, a useful special case, are particularly amenable to efficient numerical solution. Even in the general case, instantaneous coverage approximation allows the reduction of some cyclic models to more readily solvable acyclic models. After considering the solution of single-phase models, the discussion is extended to phased-mission models. Phased-mission reliability models are classified based on the state restoration behavior that occurs between mission phases. As an economical approach for the solution of such models, the mean failure rate solution method is introduced. A numerical example is used to show the influence of fault-model parameters and interphase behavior on system unreliability.

Mcgough, John↗
DOE OSTI2020

Model for Collaboration among Carriers to Reduce Empty Container Truck Trips

In recent years, intermodal transport has become an increasingly attractive alternative to freight shippers. However, the current intermodal freight transport is not as efficient as it could be. Oftentimes an empty container needs to be transported from the empty container depot to the shipper, and conversely, an empty container needs to be transported from the receiver to the empty container depot. These empty container movements decrease the freight carrier’s profit, as well as increase traffic congestion, decrease roadway safety, and add unnecessary emissions to the environment. To this end, our study evaluates a potential collaboration strategy to be used by carriers for domestic intermodal freight transport based on an optimization approach to reduce the number of empty container trips. A binary integer-linear programming model is developed to determine each freight carrier’s optimal schedule while minimizing its operating cost. The model ensures that the cost for each carrier with collaboration is less than or equal to its cost without collaboration. It also ensures that average savings from the collaboration are shared equally among all participating carriers. Additionally, two stochastic models are provided to account for uncertainty in truck travel times. The proposed collaboration strategy is tested using empirical data and is demonstrated to be effective in meeting all of the shipment constraints.

42 ENGINEERING↗
DOE OSTI2025

First-Principles Cost Analysis of Advanced High-Temperature Nuclear Plants

Due to the vast number of recent nuclear reactor innovations, particularly those pertaining to generation IV reactor types like high-temperature gas cooled reactors (HTGRs) and sodium-cooled fast reactors (SFRs), and the newer deployment strategies envisioned, such as use of small modular reactors (SMRs) or even microreactors, reliable, detailed, and complete costs of these nuclear innovations are needed in wide availability. The types of models that generally achieve these objectives are those incorporating the fundamental nature of the real-world systems they aspire to predict, such as first-principles models. Furthermore, first principles models typically offer predictiveness that is not attained by most other types of individual-models. However, detailed, first-principles cost modeling of nuclear reactors and entire nuclear plants is relatively limited. To address this limitation in the availability of detailed, predictive models based on fundamentals, we recently developed a range of cost models, mostly based on first-principles methodologies, to project full lifecycle costs (LCCs) of nuclear power plants (NPPs) based on multiple parallel SM-HTG-pebble bed reactors (PBRs) and SM-SFRs.

Prosser, Jacob H. [Strategic Analysis, Inc., Arlin↗
DOE OSTI2025

First-Principles Cost Analysis of Advanced High-Temperature Nuclear Plants

Due to the vast number of recent nuclear reactor innovations, particularly those pertaining to generation IV reactor types like high-temperature gas cooled reactors (HTGRs) and sodium-cooled fast reactors (SFRs), and the newer deployment strategies envisioned, such as use of small modular reactors (SMRs) or even microreactors, reliable, detailed, and complete costs of these nuclear innovations are needed in wide availability. The types of models that generally achieve these objectives are those incorporating the fundamental nature of the real-world systems they aspire to predict, such as first-principles models. Furthermore, first principles models typically offer predictiveness that is not attained by most other types of individual-models. However, detailed, first-principles cost modeling of nuclear reactors and entire nuclear plants is relatively limited. To address this limitation in the availability of detailed, predictive models based on fundamentals, we recently developed a range of cost models, mostly based on first-principles methodologies, to project full lifecycle costs (LCCs) of nuclear power plants (NPPs) based on multiple parallel SM-HTG-pebble bed reactors (PBRs) and SM-SFRs.

Prosser, Jacob H. [Strategic Analysis, Inc., Arlin↗
DOE OSTI2020

BEPAM-E Model Code and CABBI Simulation Results for "Repeal of the Clean Power Plan: Social Cost and Distributional Implications"

The dataset consists of results and various input data that are used in the GAMS model for the publication "Repeal of the Clean Power Plan: Social Cost and Distributional Implications". All the data are either excel files or in the .inc format which can be read within GAMS or Notepad. Main data sources include: agriculture, transportation and electricity data. Model details can be found in the paper and the GAMS model package.

carbon abatement↗
NASA NTRS1977

A prediction model to forecast the cost impact from a break in the production schedule

The losses which are experienced after a break or stoppage in sequence of a production cycle portends an extremely complex situation and involves numerous variables, some of uncertain quantity and quality. There are no discrete formulas to define the losses during a gap in production. The techniques which are employed are therefore related to a prediction or forecast of the losses that take place, based on the conditions which exist in the production environment. Such parameters as learning curve slope, number of predecessor units, and length of time the production sequence is halted are utilized in formulating a prediction model. The pertinent current publications related to this subject are few in number, but are reviewed to provide an understanding of the problem. Example problems are illustrated together with appropriate trend curves to show the approach. Solved problems are also given to show the application of the models to actual cases or production breaks in the real world.

Delionback, L. M.↗
DOE OSTI2019

PlumeSeeker{sup TM}: A Model-Based Least-Cost Monitoring Network Design Technology for 3-D Contaminant Plume Boundary Delineation - 19582

Delineating the extent of contamination in an aquifer is a pre-requisite for designing remediation schemes as well as for satisfying regulators and stakeholders. Contaminant plumes are typically delineated using either monitoring well locations with observed concentrations below remedial goals or with computer-drawn contour maps based on available concentration measurements in the groundwater. Computer-generated plume information lacks ground truth resulting in uncertainty about the true limits of contamination. The location of groundwater delineation wells is usually chosen solely based on professional judgement and experience. Both approaches can be inefficient, risky and often unnecessarily expensive. PlumeSeeker{sup TM} is a software-based technology well-suited for the optimal delineation of radiological or emerging contaminant plumes with single or multiple source locations. The software is an enhancement of a university research code for plume delineation using geostatistical and stochastic modeling tools integrated with the widely used groundwater flow and transport modeling software MODFLOW-SURFACT{sup TM}. PlumeSeeker{sup TM} increases the overall confidence in the location and geometry of the plume boundary through the sequential (i.e. a rank-ordered listing) or batch (i.e. a suite of multiple wells) selection of existing or new monitoring wells based on the criteria of maximizing plume boundary uncertainty reduction and on new field information. Using PlumeSeeker{sup TM}, remediation managers can optimally locate new wells at sites where well installation costs are high or hydrogeology is complex. Applicable at sites with or without existing monitoring wells, PlumeSeeker{sup TM} is particularly powerful for optimally allocating project resources (labor, well installation, and laboratory costs) between existing wells and sampling at new locations. An application of PlumeSeeker{sup TM} at a DoD installation demonstrates how the cost of delineating a plume can be minimized. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Modeling Electric Generation Capital Costs with Uncertain Future CO 2 Pricing

As new environmental regulations are reevaluated and various tax subsidies begin to expire, the outlook for investors in power generation may be more uncertain than ever. There are many electric power generation studies and forecasts published by a wide array of entities from private consulting firms to government agencies and national labs. These studies show which power generation technologies are favored to be constructed under the assumptions within each future scenario, and many people in businesses and government use these studies for planning purposes and decision-making. One common need for assumptions in these studies is the rate of return investors will require for constructing new generation. It is shown in this paper that for each one percent added to the cost of capital (CoC) above a base level, the levelized cost of electricity (LCOE) increases by 1-to-4 percent for generation with a 30-year life and debt term, a length commonly used for conventional generation. Therefore, if analysts make a distinction in the CoC for different technologies without quantitative support, it could result in misleading technologies being chosen as favored when facing regulatory uncertainty. The practice of adding a penalty (percentage adder) to the CoC was initially discovered in the Annual Energy Outlook, published by the U.S. Energy Information Administration (EIA). This paper presents the framework typically used in scenario analysis for selecting a CoC, consistent with the practice in long-range planning models that seek to identify the best future generation technologies for meeting electricity demand. Examples are provided on why full specification and consistency is necessary to obtain accurate results for any scenario. It is also shown in this paper how the mischaracterization of regulatory uncertainty to address the uncertainty about CO2 mitigation in a scenario can lead to a misleading outcome when applying a risk penalty to the CoC. The analysis presented shows that applying a 3-percentage penalty to the CoC for fossil generation implies a different price per ton for each generation technology, which suggests the uncertainty about CO2 regulations would best be addressed through pricing sensitivity analyses rather than penalties added to the CoC.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS2019

Cost Breakeven Analysis of Lunar ISRU for Human Lunar Surface Architectures

The return of humans to the lunar surface encompasses a range of possible architectures from brief Apollo-like sorties to long-term sustainment of human presence. Any architecture in this span requires propellant for the crew’s ascent from the lunar surface, as well as consumables to support their presence on the Moon. Oxygen and hydrogen are candidates for the propellant for the ascent vehicle due to their high specific impulse and potential for production from lunar resources and also constitute important consumables for the crew. Thus, the production of oxygen and/or hydrogen from lunar resources could significantly reduce the mass that must be sent from Earth to enable future human lunar missions. To assess the merits of using lunar resources, the costs associated with developing, producing, launching, operating, and maintaining those systems must be considered relative to the costs of delivering the needed resources from Earth. The demand for those resources depends upon the nature of the lunar mission, while the costs of both Earth-derived and lunar-derived resources depend on the performance requirements and technology capabilities associated with each approach. Thus, determining which approach is more cost efficient requires modeling the performance and cost of the associated systems as well as the range of possible architectures over which such a determination might apply. This research proposes a model that parametrically captures the factors influencing the relevant costs of providing propellant and crew consumables on the lunar surface from Earth and from the Moon. Two ISRU system models are assessed relative to propellant delivery from Earth. In this model, lunar ISRU breaks even with propellant delivery from Earth at high propellant demands and mission durations with multi-year ISRU system lifetimes; however, the costs of developing the necessary technologies to support a highly reliable and autonomous lunar ISRU system were not included.

ISRU↗
NASA NTRS1998

Parallel Load Balancing for Adaptive Unstructured Meshes

Mesh adaption is a powerful tool for efficient unstructured-grid computations but causes load imbalance among processors on a parallel machine. We describe a novel method to dynamically balance the processor workloads with a global view. Mesh question, repartitioning, processor assignment, and remapping are critical components of the framework that must be accomplished rapidly and efficiently so as not to cause a significant overhead to the numerical simulation. A data redistribution model will also be presented that predicts the remapping cost. This model is required to determine whether the gain from a balanced workload distribution offsets the cost of data movement. Results presented will demonstrate that this is an effective dynamic load balancing strategy which remains viable on a large number of processors.

Biswas, Rupak↗
DOE OSTI2026

Optimal Design and Techno-Economic Analysis of 3D-Printed, Intensified Packings for Absorbers and Strippers in Solvent-Based CO 2 Capture

A potential technology for the CO 2 absorption process is utilizing intensified structured packing with embedded cooling/heating channels for continuous heat exchange, which can overcome limitations of discrete methods, such as discrete intercooling and centralized reboilers, to aid in reducing energy consumption and decreasing costs. This work investigates the modeling of intensified packing (IP) for the stripper tower, extending on previous work for the absorber, which distributes heat internally within the column, improving the thermodynamics for the solvent regeneration process. The model includes submodels for steam turbine extraction to produce steam at various qualities as well as a surrogate model for calculating steam enthalpy. A cost model for a plant-scale absorption capture process was developed, allowing for the design of the plant to be optimized, subject to minimizing capture cost using two different power plant flue gas sources. In this optimization, the placement of IP in both towers is optimized to balance the trade-off between enhanced heat transfer and reduced mass transfer volume. For natural gas combined cycle flue gas, the standard process configuration had a minimum cost of $\$$65.40/tonne CO 2 , and considering IP, the minimum capture cost is reduced to $\$$62.73/tonne, with utilization in the stripper column, which reduces yearly costs by up to $\$$2.67 MM/yr. Cooling the absorber through IP, or intercoolers, was only found to be beneficial at higher capture rates, with IP in both towers having a cost of capture of $\$$68.08/tonne at 99.9% capture, a reduction of $\$$12.64/tonne when using only intercoolers at the same capture rate. When capturing from pulverized-coal power plants, the minimum cost of capture when using IP in both towers is $\$$44.18/tonne (at 97% capture), while the standard configuration with and without intercoolers was $\$$45.69 and $\$$47.22 per tonne, respectively. This results in a reduction in yearly costs of $\$$16.98 MM/yr from the base-case configuration. At this higher CO 2 concentration, cooling in the absorber from the IP becomes extremely beneficial, reducing energy consumption by up to 6%.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS1994

Integrating O/S models during conceptual design, part 1

The University of Dayton is pleased to submit this report to the National Aeronautics and Space Administration (NASA), Langley Research Center, which integrates a set of models for determining operational capabilities and support requirements during the conceptual design of proposed space systems. This research provides for the integration of the reliability and maintainability (R&M) model, both new and existing simulation models, and existing operations and support (O&S) costing equations in arriving at a complete analysis methodology. Details concerning the R&M model and the O&S costing model may be found in previous reports accomplished under this grant (NASA Research Grant NAG1-1327). In the process of developing this comprehensive analysis approach, significant enhancements were made to the R&M model, updates to the O&S costing model were accomplished, and a new simulation model developed. This is the 1st part of a 3 part technical report.

Ebeling, Charles E.↗
DOE OSTI2022

Generation Plant Cost of Operations and Cycling Optimization Model (Final Technical Report)

Modern coal plants are a masterpiece of engineering, having been refined and improved over more than a century. As they evolved, they have grown more efficient and cleaner. At the same time, they have grown much larger and increasingly designed to operate on very specific fuels at or near the maximum capacity, providing baseload power. In recent decades, however, they have been called on to operate at reduced capacity (cycled) at a loss of efficiency and possibly accelerated wear and tear. The purpose of this project was to develop a model to accurately estimate the cost of cycling large coal plants so that they can be operated efficiently as part of a comprehensive strategy for generation planning and dispatch. The final goal is a model which is commercial-ready that can be “tuned” to different plants for widespread use.

20 FOSSIL-FUELED POWER PLANTS↗