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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Controlling homogenization length scales and microstructure in additively manufactured Ti-Ta functionally graded materials

Materials with smooth compositional gradients or functionally grade materials (FGMs) produced via additive manufacturing (AM), enables joining dissimilar materials and optimizing multiple properties in advanced engineering applications. However, as-printed AM microstructures exhibit micro-segregation and solidification defects which, when combined with controlling macroscale gradient properties, complicates necessary post-processing. Here, we use CALPHAD-informed diffusion modelling to design post-processing heat treatments for lightweight to refractory FGMs. Ti-Ta (0 to 85 at. % Ta) FGMs were fabricated using laser-based directed energy deposition AM. Post-processing heat treatments at 1000° C and 1500° C were designed to promote homogenization across specific length scales and experimentally validated. Investigation of chemical segregation and microstructures demonstrated that the length scale of homogenization is controlled as a function of time, temperature, and local composition. Ta-rich regions exhibited incomplete homogenization compared to Ti-rich layers. Unmelted Ta particles were found to completely dissolve at 1500 °C. By controlling cooling rate (200 °C/min), martensitic structures were produced between 14–36 at. % Ta, consistent with martensite-start temperatures calculations, while furnace cooling (2 °C/min) produced α+β morphologies. This work establishes a validated predictive framework for designing post-processing to tailor microstructure and chemical architecture in AM FGMs, facilitating their deployment in demanding environments.

Materials science↗
NASA NTRS1983

Measurement of heat pump processes induced by laser radiation

A series of experiments was performed in which a suitably tuned CO2 laser, frequency doubled by a Tl3AsSe37 crystal, was brought into resonance with a P-line or two R-lines in the fundamental vibration spectrum of CO. Cooling or heating produced by absorption in CO was measured in a gas-thermometer arrangement. P-line cooling and R-line heating could be demonstrated, measured, and compared. The experiments were continued with CO mixed with N2 added in partial pressures from 9 to 200 Torr. It was found that an efficient collisional resonance energy transfer from CO to N2 existed which increased the cooling effects by one to two orders of magnitude over those in pure CO. Temperature reductions in the order of tens of degrees Kelvin were obtained by a single pulse in the core of the irradiated volume. These measurements followed predicted values rather closely, and it is expected that increase of pulse energies and durations will enhance the heat pump effects. The experiments confirm the feasibility of quasi-isentropic engines which convert laser power into work without the need for heat rejection. Of more immediate potential interest is the possibility of remotely powered heat pumps for cryogenic use, such applications are discussed to the extent possible at the present stage.

Garbuny, M.↗
DOE OSTI2018

Utilization of Wet Forest Biomass as both the Feedstock and Electricity Source for an Integrated Biochar Production System

Abstract. A belt dryer and gasifier generator set were integrated into a biochar production plant to use process heat to dry biomass feedstock from forest residuals and to provide electric power to the plant using a side stream of dried biomass. Experiments were conducted to characterize the dryer throughput and drying capacity using process heat from a stack heat exchanger attached to the biochar machine flare. A matrix of tests was conducted at high and low flow rates for both the heat exchanger air flow rate (which varied the temperature and heat input to the dryer) and the residence time of feedstock in the belt dryer. Mean feedstock input moisture during dryer characterization was 45% and the mean moisture after exiting the dryer was 27%. The optimal test condition, providing the greatest water removal rate, was determined to have high air flow rate through the heat exchanger and short dryer residence time. This condition was used to demonstrate the integrated system for an 8-h production day. The integrated system dried incoming feedstock from 36% to 22% with a dryer throughput rate of 495 kg h -1 w.b. and an evaporation rate of 88.8 kg h -1 , providing the necessary dry feedstock for the 20-kW gasifier generator set and the biochar machine, which produced 75 kg h -1 of biochar. This system required the operational effort of 0.92 labor hours per production hour. Results from this demonstration indicate that the integrated system provides key benefits in a biochar production operation including greater control of feedstock drying and the ability to operate without an external (non-biomass) source of fuel for electricity generation. Keywords: Biochar, Biomass, Biomass drying, Forest residuals, Gasification, Pyrolysis.

Agriculture↗
DOE OSTI2025

Design Assessment of Brayton Cycles for Combined Heat and Power from Nuclear Power Plants

Brayton cycles (BCs) are gaining renewed interest for use in high-temperature nuclear reactors for power production. This study explores the potential of nuclear Brayton systems in industrial combined heat and power (CHP) production. After a review of the historical deployment and technical development of BC systems for nuclear and cogeneration applications several BCs in CHP configurations are assessed when applied to representative high-temperature reactor types. The analysis emphasizes process heat delivery options, electrical efficiency, and component performance for the case of a direct cycle—Helium BC in a high temperature gas reactor, and an open-air Brayton cycle with a high temperature gas reactor. The results highlight thermodynamic trade-offs in cogeneration operation, particularly in recuperated configurations, and compare BC-based CHP with conventional Rankine cycle (RC) performance. Key findings suggest Helium BCs offer viable CHP performance primarily at lower process heat temperatures, with open air cycles being less efficient. The work also demonstrates trade-off between CHP performance and power production performance with a detailed comparison to where steam RC has better performance. The work is designed to be used as a reference work when cogeneration is proposed from high temperature reactors alongside the use of BCs.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Low-cost buffer storage for solar industrial steam applications

Motivation and importance: Many industrial process heat consumers operate throughout the day, and deep decarbonization with solar energy requires thermal energy storage. Thermal energy storage provides an additional operational benefit of firm delivery of steam – essential to reducing the risk of costly production interruptions. The group of process heat consumers that use steam for biofuels production for the California transportation fuels market is incentivized through the Low Carbon Fuel Standard (LCFS) to reduce their carbon intensity through the use of solar steam. Examples include ethanol and dimethyl ether production. The production of these and other fuels involves distillation driven by steam reboilers with steam pressures in the range 100-280 psig. These pressures can be delivered from the type of thermal energy storage that has been the focus of this project – a steam accumulator Sunvapor, Inc. (SVI) calls a “Bullet Steam Accumulator” or “BSA TM ”. Our project adds to the understanding of the design and integration of steam accumulators charged by solar thermal energy in a biofuels production facility, and similar facilities that consume process steam. The fuel application requires a demanding level of Process Safety Management not found in other steam applications. The type of steam accumulator SVI engineered and built integrates steam generation and storage in one vessel to reduce cost. Achieving a first of a kind permit to operate such a first device has also added to the understanding of the industrial application of such systems. Goals: The overall goal of the project has been to demonstrate the advantages that a “Bullet Steam Accumulator” (BSA™) can provide to solar steam integration with a manufacturing process. The industrial host has already been convinced of the potential of the available solar steam to lower than carbon intensity score. They have been interviewed for a number of publications such as that tout the advantages SVI’s system brings to their operations. Accomplishments: At the end of 2023 Sunvapor placed in service the country’s first industrial solar boiler with thermal energy storage. At the same time, this placement in service represents the first pilot commercial system to decarbonize biofuels production through the use of solar thermal energy. While the full technical effectiveness will be shown as soon as the customer’s plant is able to consume the available steam, the economic feasibility was indicated early in the project when the combination of costs and steam pricing required to meet investor expectations was determined. The project represents a reference pilot from which a full-scale commercial system may be expanded. This pilot is a necessary first step in providing the full potential benefits to the public, including decarbonization of transportation fuels. The decarbonization of the separation steps in fuels production may be the most cost-effective and nearest term solar fuel. Co-benefits include a reduction of air pollutants such as NOx and particulate matter, and job creation for the construction, operation and maintenance of industrial solar facilities.

14 SOLAR ENERGY↗
NASA NTRS1994

Brief Communication: A Simplified Approach to Transient Convective Droplet Evaporation and Burning

Empirical correlations for evaporation rates from single fuel droplets have existed since the 1930s. These correlations, which will be referred to in this article as Froessling/Ranz-Marshall types of correlations, are appropriate to the special cases of steady-state evaporation in the absence of chemical reaction. In a previous article by the authors, the quasi-steady evaporation and burning processes associated with a fuel drop in a convective environment are examined through a droplet model based on the boundary layer approach. For droplet Reynolds numbers of practical interest, this model produces very reasonable steady state as well as quasi-time-dependent droplet simulations, requiring relatively short computational times and yielding good agreement with the above-mentioned empirical correlations. The steady-state case, however, is usually relevant to practical combustor situations only when the drop has reached a nearly uniform temperature since the heating process of the drop cannot be considered to be quasi-steady. In the present study, the transient heating process of the droplet interior during evaporation and/or burning is taken into account, and thus calculations pertaining to the entire life-time of the droplet are carried out. It is of particular interest here to obtain simplified correlations to describe the transient behavior of evaporating and burning droplets; these may be incorporated with greater ease into spray calculations. Accordingly, we have chosen to use stagnation conditions in the present model in a modification of the Froessling/Ranz-Marshall correlations. These modified correlations, incorporating an effective transfer number, produce a fairly accurate representation of droplet evaporation and burning, while requiring only one tenth the computational effort used in a full boundary layer solution.

Madooglu, K.↗
DOE OSTI2019

Anisotropic Thermal and Mechanical Characteristics of Graphene: A Molecular Dynamics Study

In the present work, molecular dynamics simulation has been performed to characterize the thermal and mechanical behavior of graphene sheet. For this purpose, graphene sheet is subjected to dynamic heating process and its melting point has been predicted. Structural and thermal properties have been analyzed using radial distribution function and energy per atom. To analyze factors affecting melting temperature, four graphene sheets with different dimensions have been chosen for the dynamic heating process. The melting temperature of graphene decreases with increase in the sheet dimension, hence graphene sheet having smaller dimensions show relatively better thermal stability. To analyze the mechanical behavior, graphene sheet has been subjected to uniaxial tensile loading along zigzag and armchair directions respectively. It is observed that zigzag-oriented graphene sheet shows high fracture strength and stability as compared to armchair direction. Multilayer graphene sheets have been selected to investigate the effect of multilayers on the mechanical strength. It can be revealed from results that fracture strength decreases with increase in layers, however, brittleness of the sample relatively decreases with increase in a number of graphene layers.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1981

USAF solar thermal applications case studies

The potential of solar energy technologies to meet mission related applications for process heat was investigated. The reduction of the dependence of military installations on fossil fuels by promoting the use of more abundant resources where liquid hydrocarbons and natural gas are now used is examined. The evaluation and utilization of renewable energy systems to provide process heat and space heating are emphasized. The application of thermal energy systems is divided into four steps: (1) investigation of the potential operational cost effectiveness of selected thermal technologies; (2) selection of a site and preliminary design of point focussing solar thermal plant; (3) construction and test of an engineering prototype; and (4) installation and operation of a solar thermal energy plant.

Source record↗
NASA NTRS2012

Upper-Ocean Heat Balance Processes and the Walker Circulation in CMIP5 Model Projections

Considerable uncertainty remains as to the importance of mechanisms governing decadal and longer variability of the Walker Circulation, its connection to the tropical climate system, and prospects for tropical climate change in the face of anthropogenic forcing. Most contemporary climate models suggest that in response to elevated CO2 and a warmer but more stratified atmosphere, the required upward mass flux in tropical convection will diminish along with the Walker component of the tropical mean circulation as well. Alternatively, there is also evidence to suggest that the shoaling and increased vertical stratification of the thermocline in the eastern Pacific will enable a muted SST increase there-- preserving or even enhancing some of the dynamical forcing for the Walker cell flow. Over the past decade there have been observational indications of an acceleration in near-surface easterlies, a strengthened Pacific zonal SST gradient, and globally-teleconnected dislocations in precipitation. But is this evidence in support of an ocean dynamical thermostat process posited to accompany anthropogenic forcing, or just residual decadal fluctuations associated with variations in warm and cold ENSO events and other stochastic forcing? From a modeling perspective we try to make headway on this question by examining zonal variations in surface energy fluxes and dynamics governing tropical upper ocean heat content evolution in the WCRP CMIP5 model projections. There is some diversity among model simulations; for example, the CCSM4 indicates net ocean warming over the IndoPacific region while the CSIRO model concentrates separate warming responses over the central Pacific and Indian Ocean regions. The models, as with observations, demonstrate strong local coupling between variations in column water vapor, downward surface longwave radiation and SST; but the spatial patterns of changes in the sign of this relationship differ among models and, for models as a whole, with observations. Our analysis focuses initially on probing the inter-model differences in energy fluxes / transports and Walker Circulation response to forcing. We then attempt to identify statistically the El Nino- / La Nina-related ocean heat content variability unique to each model and regress out the associated energy flux, ocean heat transport and Walker response on these shorter time scales for comparison to that of the anthropogenic signals.

Robertson, F. R.↗
DOE OSTI2023

Renewable Thermal Energy Systems: Systemic Challenges and Transformational Policies (Report 2)

Two important challenges for RTES are the need for significant further innovation and deployment, particularly in the United States. In the face of continued success of other renewable energy technologies, such as solar photovoltaics (PV) and land-based wind energy for electricity, it is worthwhile to evaluate the current state of select RTES technologies in the context of technology innovation systems and energy transitions. This report marks a departure from the existing body of research we are aware of and have contributed to relating to RTES applications for industrial process heat in the United States. Our objectives for this report are fourfold: 1) Begin considering the challenges of RTES deployment in the United States through application of socio-technical and transitions frameworks; 2) Begin applying the theory of RTES as configurational technology innovation systems in the United States and for industrial process heat specifically; 3) Review RTES innovation, policies, and market formation activities in the contexts of Objectives 1 and 2; 4) Identify future paths for RTES research. Ultimately, the challenges associated with scaling the deployment of RTES in the United States are related to the need to develop a well-functioning innovation system that can overcome resistance from a highly stable socio-technical regime within a shrinking window of time to address the climate crisis, U.S. industrial competitiveness, and volatile energy commodity price shocks. Current efforts toward scaling for RTES applications in industry and buildings emphasize the need for further cost reductions, but not for interventions that support actors and their interactions and that increase the legitimacy of the technologies. As a result, there are significant opportunities to analyze the social contexts of RTES that can then be used to inform the design of effective, transformational policy portfolios.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Shock compaction heating and collisional processes in the production of type 3 ordinary chondrites: Lessons from the (nearly) unique L3 chondrite melt breccia Northwest Africa 8709

Abstract Northwest Africa (NWA) 8709 is a rare example of a type 3 ordinary chondrite melt breccia and provides critical information for the shock compaction histories of chondrites. An L3 protolith for NWA 8709 is inferred on the basis of oxygen isotope composition, elemental composition, diverse mineral chemistry, and overall texture. NWA 8709 is among the most strongly shocked type 3 chondrites known, and experienced complete melting of the matrix and partial melting of chondrules. Unmelted phases underwent FeO reduction and partial homogenization, with reduction possibly occurring by reaction of olivine and low‐Ca pyroxene with an S‐bearing gas that was produced by vaporization. Chondrules and metal grains became foliated by uniaxial compaction, and during compression, chondrules and fragments became attached to form larger clumps. This process, and possibly also melt incorporation into chondrules to cause “inflation,” may have contributed to anomalously large chondrule sizes in NWA 8709. The melt breccia character is attributed to strong shock affecting a porous precursor. Data‐model comparisons suggest that a precursor with 23% porosity that was impacted by a 3 km/s projectile could have produced the meteorite. The rarity of other type 3 ordinary chondrite melt breccias implies that the immediate precursors to such chondrites were lower in porosity than the NWA 8709 precursor, or experienced weaker shocks. Altogether, the data imply a predominantly “quiet” dynamical environment to form most type 3 ordinary chondrites, with compaction occurring in a series of relatively weak shock events.

Ruzicka, Alex M.↗
NASA NTRS1995

Alpha particle heating at comet-solar wind interaction regions

The satellite observations at comet Halley have shown strong heating of solar wind alpha particles over an extended region dominated by high-intensity, low-frequency turbulence. These waves are excited by the water group pickup ions and can energize the solar wind plasma by different heating processes. The alpha particle heating by the Landau damping of kinetic Alfven waves and the transit time damping of low-frequency hydromagnetic waves in this region of high plasma beta are studied in this paper. The Alfven wave heating was shown to be the dominant mechanism for the observed proton heating, but it is found to be insufficient to account for the observed alpha particle heating. The transit time damping due to the interaction of the ions with the electric fields associated with the magnetic field compressions of magnetohydrodynamic waves is found to heat the alpha particles preferentially over the protons. Comparison of the calculated heating times for the transit time damping with the observations from comet Halley shows good agreement. These processes contribute to the thermalization of the solar wind by the conversion of its directed energy into the thermal energy in the transition region at comet-solar wind interaction.

Sharma, A. S.↗
DOE OSTI2020

Significance of a Solid Electrolyte Interphase on Separation of Anode and Cathode Materials from Spent Li-Ion Batteries by Froth Flotation

The separation of electrode active materials from spent Li-ion batteries (LIBs) by froth flotation is challenging due to the changes in surface properties of electrode active materials from cycling as well as the presence of organic binders. In this work, the froth flotation separation of aged anode and cathode composite materials from spent LIBs was systematically investigated after the materials were heat treated. The results show that aged anode and cathode materials from spent LIBs can be well separated from each other after a heating process in air at 400 degrees C and at which some of the PVDF binder remains intact. The underlying mechanism was investigated by X-ray photoelectron spectroscopy (XPS), contact angle measurements, and scanning transmission electron microscopy (STEM) coupled with energy-dispersive X-ray spectroscopy (EDX). The results from the XPS and contact angle measurements show that there is a hydrophilic and oxygen-rich layer on the surface of aged anode materials. This hydrophilic surface, associated with the solid electrolyte interface (SEI) layer, impacts the froth flotation process significantly. The results also show that both the SEI layers and PVDF binder residues on the surface are removed at 400 degrees C for an hour, restoring the hydrophobicity of the anode materials, which, in turn, benefits the separation of anode and cathode materials. The STEM/EDX elemental analysis data confirms that there are 20 nm-thick oxygen-rich SEI layers on the surfaces, which can be removed after a heating process. The present result illustrates the significance of the SEI layers in flotation separation of electrode materials and sheds new lights into the future development of the recycling processes for the separation of anode and cathode composite materials from spent Li-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Tracking the Influence of Thermal Expansion and Oxygen Vacancies on the Thermal Stability of Ni-Rich Layered Cathode Materials

The ever-growing demand for high-energy lithium-ion batteries in portable electronics and electric vehicles has triggered intensive research efforts over the past decade. An efficient strategy to boost the energy and power density of lithium-ion batteries is to increase the Ni content in the cathode materials. However, a higher Ni content in the cathode materials gives rise to safety issues. Herein, thermal expansion and oxygen vacancies are proposed as new critical factors that affect the thermal stability of charged Ni-rich cathode materials based on a systematic synchrotron-based X-ray study of Li 0.33 Ni 0.5+x Co 0.2 Mn 0.3-x O 2 (x = 0, 0.1, 0.2) cathode materials during a heating process. Charged cathode materials with higher Ni contents show larger thermal expansion, which accelerates transition metal migration to the Li layers. Oxygen vacancies are formed and accumulate mainly around Ni ions until the layered-to-spinel phase transition begins. The oxygen vacancies also facilitate transition metal migration to the Li layers. Thermal expansion and the presence of oxygen vacancies decrease the energy barrier for cation migration and facilitate the phase transitions in charged cathode materials during the heating process. These results provide valuable guidance for developing new cathode materials with improved safety characteristics.

25 ENERGY STORAGE↗
DOE OSTI2021

Potential Early Markets for Fusion Energy

We examine potential early markets for fusion energy and their projected cost targets, based on analysis and synthesis of many relevant, recent studies and reports. Seeking to provide guidance to ambitious fusion developers aspiring to enable commercial deployment before 2040, we examine cost requirements for fusion-generated electricity, process heat, and hydrogen production based on today’s market prices but with various adjustments relating to possible scenarios in 2035, such as ‘‘business-as-usual,’’ high renewables penetration, and carbon pricing up to 100 $/tCO 2 . Key findings are that fusion developers should consider focusing initially on high-priced global electricity markets and consider including integrated thermal storage, depending on techno-economic factors, in order to maximize revenue and compete in markets with high renewables penetration. Process heat and hydrogen production will be tough early markets for fusion, but may open up to fusion as markets evolve and if fusion’s levelized cost of electricity falls below 50 $/MWh e . Finally, we discuss potential ways for a fusion plant to increase revenue via cogeneration (e.g., desalination, direct air capture, or district heating) and to lower capital costs (e.g., by minimizing construction times and interest or by retrofitting coal plants).

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2016

Sequential control of step-bunching during graphene growth on SiC (0001)

We have investigated the relation between the step-bunching and graphene growth phenomena on an SiC substrate. We found that only a minimum amount of step-bunching occurred during the graphene growth process with a high heating rate. On the other hand, a large amount of step-bunching occurred using a slow heating process. These results indicated that we can control the degree of step-bunching during graphene growth by controlling the heating rate. We also found that graphene coverage suppressed step bunching, which is an effective methodology not only in the graphene technology but also in the SiC-based power electronics.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Evaluating the Techno-Economic Feasibility of Forward Osmosis Process Utilizing Low Grade Heat: Applications in Power Plant Water, Wastewater, and Reclaimed Water Treatment

Recovering and using uncoverted heat produced during electric power generation holds potential to significantly improve the efficiency of the electric power industry. One potential use of this low-temperature waste heat is on-site water treatment using waste heat driven processes to comply with the 2015 Effluent Limitation Guidelines for the Steam Electric Generating Sector. Ammonia-carbon dioxide forward osmosis (NH 4 HCO 3 FO) is a two-step waste heat driven process that involves a membrane separation process in which an osmotic pressure gradient created by an NH 4 HCO 3 draw solution is used to pull water across the membrane and a distillation column to regenerate the NH 4 HCO 3 draw solution. In this work we estimate the quantity, quality, and spatio-temporal availability of waste heat produced at U.S. coal, nuclear, and natural gas plants. We combine these estimates of waste heat availability with a techno-economic optimization model of NH 4 HCO 3 FO in order to assess the potential of NH 4 HCO 3 FO to treat flue gas desulfurization (FGD) wastewater, gasification wastewater, and boiler feedwater. We find that in 2012, 18.9 billion GJ of waste heat was discharged from the U.S. coal, natural gas, and nuclear fleet, although only 900 million GJ of waste heat was discharged at temperatures suitable for NH 4 HCO 3 FO. A maximum of 1.9 billion m3/yr of water could be produced using this waste heat to drive a NH 4 HCO 3 FO. The costs of waste heat driven NH 4 HCO 3 FO for FGD and gasification wastewater treatment to zero liquid discharge (ZLD) and boiler feedwater treatment are 2.20-2.40/m 3 and 0.35-0.65/m 3 , respectively. With mechanical vapor compression and crystallization for ZLD wastewater treatment and reverse osmosis for boiler feedwater treatment as the cost benchmark technologies, waste heat driven NH 4 HCO 3 FO is cost competitive for ZLD wastewater treatment, but not boiler feedwater treatment.

20 FOSSIL-FUELED POWER PLANTS↗