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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Resistively-Heated Microlith-based Adsorber for Carbon Dioxide and Trace Contaminant Removal

An integrated sorber-based Trace Contaminant Control System (TCCS) and Carbon Dioxide Removal Assembly (CDRA) prototype was designed, fabricated and tested. It corresponds to a 7-person load. Performance over several adsorption/regeneration cycles was examined. Vacuum regenerations at effective time/temperature conditions, and estimated power requirements were experimentally verified for the combined CO2/trace contaminant removal prototype. The current paper details the design and performance of this prototype during initial testing at CO2 and trace contaminant concentrations in the existing CDRA, downstream of the drier. Additional long-term performance characterization is planned at NASA. Potential system design options permitting associated weight, volume savings and logistic benefits, especially as relevant for long-duration space flight, are reviewed. The technology consisted of a sorption bed with sorbent- coated metal meshes, trademarked and patented as Microlith by Precision Combustion, Inc. (PCI). By contrast the current CO2 removal system on the International Space Station employs pellet beds. Preliminary bench scale performance data (without direct resistive heating) for simultaneous CO2 and trace contaminant removal was reviewed in SAE 2004-01-2442. In the prototype, the meshes were directly electrically heated for rapid response and accurate temperature control. This allowed regeneration via resistive heating with the potential for shorter regeneration times, reduced power requirement, and net energy savings vs. conventional systems. A novel flow arrangement, for removing both CO2 and trace contaminants within the same bed, was demonstrated. Thus, the need for a separate trace contaminant unit was eliminated resulting in an opportunity for significant weight savings. Unlike the current disposable charcoal bed, zeolites for trace contaminant removal are amenable to periodic regeneration.

Roychoudhury, S.↗
DOE OSTI2021

A permafrost implementation in the simple carbon–climate model Hector v.2.3pf

Abstract. Permafrost currently stores more than a fourth of global soil carbon. A warming climate makes this carbon increasingly vulnerable to decomposition and release into the atmosphere in the form of greenhouse gases. The resulting climate feedback can be estimated using land surface models, but the high complexity and computational cost of these models make it challenging to use them for estimating uncertainty, exploring novel scenarios, and coupling with other models. We have added a representation of permafrost to the simple, open-source global carbon–climate model Hector, calibrated to be consistent with both historical data and 21st century Earth system model projections of permafrost thaw. We include permafrost as a separate land carbon pool that becomes available for decomposition into both methane (CH4) and carbon dioxide (CO2) once thawed; the thaw rate is controlled by region-specific air temperature increases from a preindustrial baseline. We found that by 2100 thawed permafrost carbon emissions increased Hector’s atmospheric CO2 concentration by 5 %–7 % and the atmospheric CH4 concentration by 7 %–12 %, depending on the future scenario, resulting in 0.2–0.25 ∘C of additional warming over the 21st century. The fraction of thawed permafrost carbon available for decomposition was the most significant parameter controlling the end-of-century temperature change in the model, explaining around 70 % of the temperature variance, and was distantly followed by the initial stock of permafrost carbon, which contributed to about 10 % of the temperature variance. The addition of permafrost in Hector provides a basis for the exploration of a suite of science questions, as Hector can be cheaply run over a wide range of parameter values to explore uncertainty and can be easily coupled with integrated assessment and other human system models to explore the economic consequences of warming from this feedback.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1973

Finite aperture waveguide laser resonators

A general theory of finite aperture waveguide laser resonators is developed which represents the external reflectors by matrices which couple linearly polarized waveguide modes having the same azimuthal symmetry. The theory allows the determination of resonator efficiency, resonator frequencies, and laser near and far field patterns. Computations of the coupling loss for the fundamental waveguide mode as a function of mirror curvature, separation, and aperture are in agreement with recent infinite aperture calculations in the limit of large apertures and indicate three low-loss configurations: large radius of curvature mirrors close to the guide; large radius of curvature mirrors centered at the guide entrance; and generally smaller curvature mirrors separated by half their curvature from the guide entrance. Design guidelines for construction of high efficiency CO2, CO and He-Ne waveguide laser resonators are summarized in tabular form.

Degnan, J. J.↗
NASA NTRS1993

Lidar and radar derived cirrus microphysical properties for the 26 November 1991 case study

The Wave Propagation Laboratory's CO2 lidar (lambda = 10.6 microns) and Ka-band radar (lambda = 8.66 mm) operate at widely separated wavelengths; the differences in how the transmitted waves interact with cloud targets can be exploited to provide information that neither sensor could provide alone. This can be as simple as overlapping the data sets to provide additional coverage on cloud geometry (see Uttal and Intrieri, 1993) or combining the measurements in a theoretical framework to provide cirrus cloud parameters of the size spectrum, i.e., characteristic particle size and number concentration. In this paper, the latter option is described and an example case study presented to illustrate the types of information available for cloud and radiation transfer models.

Intrieri, Janet M.↗
NASA NTRS2013

Comparative Analysis of Alternative Spectral Bands of CO2 and O2 for the Sensing of CO2 Mixing Ratios

We performed comparative studies to establish favorable spectral regions and measurement wavelength combinations in alternative bands of CO2 and O2, for the sensing of CO2 mixing ratios (XCO2) in missions such as ASCENDS. The analysis employed several simulation approaches including separate layers calculations based on pre-analyzed atmospheric data from the modern-era retrospective analysis for research and applications (MERRA), and the line-byline radiative transfer model (LBLRTM) to obtain achievable accuracy estimates as a function of altitude and for the total path over an annual span of variations in atmospheric parameters. Separate layer error estimates also allowed investigation of the uncertainties in the weighting functions at varying altitudes and atmospheric conditions. The parameters influencing the measurement accuracy were analyzed independently and included temperature sensitivity, water vapor interferences, selection of favorable weighting functions, excitations wavelength stabilities and other factors. The results were used to identify favorable spectral regions and combinations of on / off line wavelengths leading to reductions in interferences and the improved total accuracy.

Pliutau, Denis↗
NASA NTRS2017

Material Analysis and System Design for Exploration Life Support Systems 2017

Advanced Environmental Control and Life Support System (ECLSS) design is critical for manned space flight beyond Earth. Current systems enable extended missions in low-Earth orbit, but for deep-space missions, not only will astronauts be outside the reach of resupply operations from Earth but they will also need to handle malfunctions and compensate for the degradation of materials. These two daunting challenges must be overcome for long-term independent space flight. In order to solve the first, separation and recycling of onboard atmosphere is required. Current systems utilize space vacuum to fully regenerate CO2 sorbent beds, but this is not sustainable. The second challenge stems from material and performance degradation due to operational cycling and on-board contaminants. This report will review the recent work by the ECLSS team at Marshall Space Flight Center towards overcoming these challenges by characterizing materials via novel methods and by assessing new air revitalization systems.

Knox, Jim↗
NASA NTRS2021

A permafrost implementation in the simple carbon-climate model Hector v.2.3.pf

Permafrost currently stores more than a fourth of global soil carbon. A warming climate makes this carbon increasingly vulnerable to decomposition and release into the atmosphere in the form of greenhouse gases. The resulting climate feedback can be estimated using land surface models, but the high complexity and computational cost of these models make it challenging to use them for estimating uncertainty, exploring novel scenarios, and coupling with other models. We have added a representation of permafrost to the simple, open-source global carbon–climate model Hector, calibrated to be consistent with both historical data and 21st century Earth system model projections of permafrost thaw. We include permafrost as a separate land carbon pool that becomes available for decomposition into both methane (CH4) and carbon dioxide (CO2) once thawed; the thaw rate is controlled by region-specific air temperature increases from a preindustrial baseline. We found that by 2100 thawed permafrost carbon emissions increased Hector’s atmospheric CO2 concentration by 5 %–7 % and the atmospheric CH4 concentration by 7 %–12 %, depending on the future scenario, resulting in 0.2–0.25 ∘C of additional warming over the 21st century. The fraction of thawed permafrost carbon available for decomposition was the most significant parameter controlling the end-of-century temperature change in the model, explaining around 70 % of the temperature variance, and was distantly followed by the initial stock of permafrost carbon, which contributed to about 10 % of the temperature variance. The addition of permafrost in Hector provides a basis for the exploration of a suite of science questions, as Hector can be cheaply run over a wide range of parameter values to explore uncertainty and can be easily coupled with integrated assessment and other human system models to explore the economic consequences of warming from this feedback.

Dawn L. Woodard↗
NASA NTRS2004

Modeling of Isotope Fractionation in Stratospheric CO2, N2O, CH4, and O3: Investigations of Stratospheric Chemistry and Transport, Stratosphere-Troposphere Exchange, and Their Influence on Global Isotope Budgets

We investigated the isotopic fractionation of CH4 and hydrogen (H2) in the stratosphere by incorporating isotope-specific rate coefficients into the Lawrence Livermore National Laboratory (LLNL) 2D model and comparing the model results with new observations from the NASA ER-2 aircraft (funded through a separate task under the Upper Atmosphere Research Program). The model results reveal that fractionation which occurs in the stratosphere has a significant influence on isotope compositions in the free troposphere, an important point which had previously been ignored, unrecognized or unquantified for many long-lived trace gases, including CH4 and H2 which we have focused our efforts on to date. Our analyses of the model results and new isotope observations have also been used to test how well the kinetic isotope effects are known, at least to within the uncertainties in model chemistry and transport. Overall, these results represent an important step forward in our understanding of isotope fractionation in the atmosphere and demonstrate that stratospheric isotope fractionation cannot be ignored in modeling studies which use isotope observations in the troposphere to infer the global budgets of CH4 (an important greenhouse gas) and of H2 (a gas whose atmospheric budget must be better quantified, particularly before a large human perturbation from fuel cell use is realized). Our analyses of model results and observations from the NASA ER-2 aircraft are briefly summarized separately below for CH4, H2, and H2O and for the contribution of these modeling studies to date to our understanding of isotope fractionation for N2O, CO2, and O3 as well.

Boering, Kristie A.↗
DOE OSTI2024

CFD modeling of high-flux plate-and-frame membrane modules for industrial carbon capture

In this work, we study the application of membrane-based separation systems for carbon capture, considering plate-and-frame membrane modules. The successful deployment of membrane CO2 capture system relies on high-performing membranes as well as effective membrane modules that can fully exploit the developed membranes. A plate-and-frame membrane module is especially attractive for CO2 capture from industrial flue gas due to its lower pressure drop compared to its counterparts such as spiral wound modules and hollow fiber modules. To design better plate-and-frame modules, we investigate their basic unit - a single membrane stack through a combination of computational modeling and experimental investigations. The modeling approach is based on Computational Fluid Dynamics (CFD) to represent a multiphysics problem, including the fluid flow and diffusion processes within a membrane module. We use experimental data collected under different operating conditions to validate the CFD model. Numerical results suggest a good agreement between experiments and model outputs for the CO2 recovery, CO2 mole fraction in the retentate and permeate, and stage-cut. The CFD model is able to predict accurately the flow behavior, providing valuable insights on the effects of fluid dynamics on mass transfer of CO2. We also carry out a sensitivity analysis to identify the effect of key parameters on the CO2 recovery and the CO2 purity of the outlet streams.

Dosso, Cheick↗
NASA NTRS1977

A mass spectrometer-beam experiment for investigations of planetary atmospheres

An experimental concept for investigation of planetary atmospheres using a mass spectrometer is discussed. High atmospheric pressures are reduced to mass spectrometer operating pressures by means of differential pumping. Sampling is accomplished through the formation of a molecular beam. A flag in front of the mass spectrometer can be used to separate ambient gases from system background. Laboratory tests have confirmed the feasibility of the experiment, particularly in CO2 dominated atmospheres.

Mauersberger, K.↗
NASA NTRS1977

Regenerable device for scrubbing breathable air of CO2 and moisture without special heat exchanger equipment

The device concerns the circulation of cabin air through canisters which absorb and adsorb carbon dioxide, together with excess moisture, and return the scrubbed air to the cabin for recirculation. A coating on an inert substrate in granular form absorbs and adsorbs the impurities at standard temperatures and pressures, but desorbs such impurities at low pressures (vacuum) and standard temperatures. This fact is exploited by making the device in a stack of cells consisting of layers or cells which are isolated from one another flow-wise and are connected to separate manifolds and valving systems into two separate subsets. A first subset may be connected for the flow breathable air therethrough until the polyethyleneimine of its cells is saturated with CO2 and H2O. During the same period the second subset of cells is manifolded to a vacuum source.

Tepper, E. H.↗
NASA NTRS1989

Three-Man Solid Electrolyte Carbon Dioxide Electrolysis Breadboard

The development of the Three-Man (2.2 lb CO2/man-day) Solid Electrolyte CO2 Electrolysis Breadboard consisted of a Phase 1 and 2 effort. The Phase 1 effort constituted fabrication of three electrolysis cell types and performing parametric testing, off-design testing, and cell life testing. The Phase 2 consisted of the preliminary design, incorporation of palladium (Pd) tubes for hydrogen separation from the electrolyzer cathode feed gases, design support testing, final design, fabrication, and performance testing of the breadboard system. The results of performance tests demonstrated that CO2 electrolysis in an oxygen reclamation system for long duration space-based habitats is feasible. Closure of the oxygen system loop, therefore, can be achieved by CO2 electrolysis. In a two step process the metabolic CO2 and H2O vapor are electrolyzed into O2, H2, and CO. The CO can subsequently be disproportionated into carbon and CO2 in a carbon deposition reactor and the CO2 in turn be recycled and electrolyzed for total O2 recovery. The development effort demonstrated electrolyzer system can be designed and built to operate safely and reliably and the incorporation of Pd tubes for hydrogen diffusion can be integrated safely with predictable performance.

Isenberg, Arnold O.↗
NASA NTRS1987

NO2 heterodyne frequency measurements with a tunable diode laser, a CO laser transfer oscillator and CO2 laser standards

Heterodyne frequency measurements have been made on selected groups of nitrogen dioxide rovibronic transitions between 1580.8 and 1650.7/cm. The groups are separated by 7 to 10/cm, and the intent is to provide a limited (and interim) calibration table for the region. In addition to a table of measured frequencies in the region, figures of spectra in the vicinity of the measured lines are included to provide a map for identifying the transitions measured.

Zink, L. R.↗
NASA NTRS2010

CO2 Removal and Atmosphere Revitalization Systems for Next Generation Space Flight

Removal of metabolic CO2 from breathing air is a vital process for life support in all crewed space missions. A CO2 removal processor called the Low Power CO2 Removal (LPCOR) system is being developed in the Bioengineering Branch at NASA Ames Research Center. LPCOR utilizes advanced adsorption and membrane gas separation processes to achieve substantial power and mass reduction when compared to the state-of-the-art carbon dioxide removal assembly (CORA) of the US segment of the International Space Station (ISS). LPCOR is an attractive alternative for use in commercial spacecraft for short-duration missions and can easily be adapted for closed-loop life support applications. NASA envisions a next-generation closed-loop atmosphere revitalization system that integrates advanced CO2 removal, O2 recovery, and trace contaminant control processes to improve overall system efficiency. LPCOR will serve as the front end to such a system. LPCOR is a reliable air revitalization technology that can serve both the near-term and long-term human space flight needs of NASA and its commercial partners.

Luna, Bernadette↗
NASA NTRS2005

On the determination of atmospheric minor gases by the method of vanishing partial derivatives with application to CO2

We present a general method for the determination of minor gases in the troposphere from high spectral resolution observations. In this method, we make use of a general property of the total differential of multi-variable functions to separate the contributions of each individual minor gas. We have applied this method to derive the mixing ratio of carbon dioxide in the mid-troposphere using data from the Atmospheric Infrared Sounder (AIRS) currently flying on the NASA Aqua Mission. We compare our results to the aircraft flask CO2 measurements obtained by H. Matsueda et al. over the western Pacific and demonstrate skill in tracking the measured 5 ppmv seasonal variation with an accuracy of 0.43 +/- 1.20 ppmv.

Atmospheric Infrared Sounder (AIRS)↗
NASA NTRS1972

Helium Leak Measurements Using CO2 as a Carrier

Detection delay defects are omitted by using helium mass spectrometer leak detector combined with several known procedures. Technique combines carbon dioxide purging, cryogenic separating helium accumulation, and use of carbon dioxide as carrier gas.

Moore, B. C.↗
DOE OSTI2024

Membrane-based carbon capture process optimization using CFD modeling

Carbon capture is a promising option to mitigate CO2 emissions from existing coal-fired power plants, cement and steel industries, and petrochemical complexes. Among the available technologies, membrane-based carbon capture presents the lowest energy consumption, operating costs, and carbon footprint. In addition, membrane processes have important operational flexibility and response times. On the other hand, the major challenges to widespread application of this technology are related to reducing capital costs and improving membrane stability and durability. To upscale the technology into stacked flat sheet configurations, high fidelity computational fluid dynamics (CFD) that describes the separation process accurately are required. High fidelity simulations have been shown to be effective in studying the complex transport phenomena in membrane systems. In addition, obtaining high CO2 recovery percentages and product purity requires a multi-stage membrane process, where the optimal network configuration of the membrane modules must be studied in a systematic way. In order to address the design problem at process scale, we formulate a superstructure for the membrane-based carbon capture, including up to three separation stages. In the formulation of the optimization problem, we include reduced models, based on rigorous CFD simulations of the membrane modules. Numerical results indicate that the optimal design includes three membrane stages, and the capture cost is 45.4 $/t-CO2.

Pedrozo, Hector A.↗
DOE OSTI2024

Optimization of Membrane-based Carbon Capture using Dimensional Analysis, CFD and Process System Engineering

Carbon capture is a promising option to mitigate CO2 emissions from existing coal-fired power plants, cement and steel industries, and petrochemical complexes. Among the available technologies, membrane-based carbon capture presents the lowest energy consumption, operating costs, and carbon footprint. In addition, membrane processes have important operational flexibil-ity and response times. On the other hand, the major challenges to widespread application of this technology are related to reducing capital costs and improving membrane stability and durability.To upscale the technology into stacked flat sheet configurations, high fidelity computational fluid dynamics (CFD) that describes the separation process accurately are required. High fidelity simulations have been shown to be effective in studying the complex transport phenomena in membrane systems. In addition, obtaining high CO2 recovery percentages and product purity requires a multi-stage membrane process, where the optimal network configuration of the membrane modules must be studied in a systematic way. In order to address the design problem at process scale, we formulate a superstructure for the membrane-based carbon capture, including up to three separation stages. In the formulation of the optimization problem, we include reduced models, based on rigorous CFD simulations of the membrane modules. Numerical results indicate that the optimal design includes three membrane stages, and the capture cost is 45.4 $/t-CO2.

Pedrozo, Hector A.↗