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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Light regulation of light-harvesting antenna size substantially enhances photosynthetic efficiency and biomass yield in green algae

One of the major factors limiting biomass productivity in algae is the low thermodynamic efficiency of photosynthesis. The greatest thermodynamic inefficiencies in photosynthesis occur during the conversion of light into chemical energy. At full sunlight the light-harvesting antenna captures photons at a rate nearly 10 times faster than the rate-limiting step in photosynthetic electron transport. Excess captured energy is dissipated by non-productive pathways including the production of reactive oxygen species. Substantial improvements in photosynthetic efficiency have been achieved by reducing the optical cross-section of the light-harvesting antenna by selectively reducing chlorophyll b levels and peripheral light-harvesting complex subunits. Smaller light-harvesting antenna, however, may not exhibit optimal photosynthetic performance in low or fluctuating light environments. Additionally, we describe a translational control system to dynamically adjust light-harvesting antenna sizes for enhanced photosynthetic performance. Furthermore, by expressing a chlorophyllide a oxygenase (CAO) gene having a 5' mRNA extension encoding a Nab1 translational repressor binding site in a CAO knockout line it was possible to continuously alter chlorophyll b levels and correspondingly light-harvesting antenna sizes by light-activated Nab1 repression of CAO expression as a function of growth light intensity. Significantly, algae having light-regulated antenna sizes had substantially higher photosynthetic rates and two-fold greater biomass productivity than the parental wild-type strains as well as near wild-type ability to carry out state transitions and non-photochemical quenching. These results have broad implications for enhanced algae and plant biomass productivity.

09 BIOMASS FUELS↗
DOE OSTI2024

Coupling thermal energy storage with a thermally anisotropic building envelope for building demand-side management across various US climate conditions

Here, the thermally anisotropic building envelope (TABE) is a novel active building envelope that enhances energy efficiency and thermal comfort in buildings by transferring heat and cold between building envelopes and hydronic loops. When coupled with thermal energy storage (TES) units, the TABE + TES enables the storage of both heat and cold energy captured by the TABE roof or exterior walls. This stored energy can be later released by the TABE floor for indoor heating and cooling, benefiting both the grid and the end user. This paper evaluates the merits of TABE + TES for building demand-side management across various US climate conditions, focusing on peak load shaving, annual energy savings, and cost savings under time-of-use (TOU) electric rate schedules. Simulations were conducted by integrating time-of-day–informed, rule-based control strategies in MATLAB, TABE components and TES units in COMSOL Multiphysics, and whole-building energy analysis in EnergyPlus. A case study using the US Department of Energy’s prototype single-family detached house model in Birmingham, Alabama; Los Angeles, California; Oak Ridge, Tennessee; and Denver, Colorado, showed that the TABE + TES system achieved (1) 70 % peak load shaving in Los Angeles and Denver and 20 % in Birmingham and Oak Ridge; (2) significant peak electricity savings of 351–497 kWh, reducing peak energy consumption by 38 %–78 %; and (3) annual heating cost savings of 0.79 $\$$/m2–1.17 $\$$/m 2 and cooling cost savings of 0.60 $\$$/m 2 –1.17 $\$$/m 2 using a normal utility rate or low-TOU rate. The benefits of employing the TABE + TES system are even more significant under high TOU rates.

25 ENERGY STORAGE↗
DOE OSTI2026

Simulations of positron injector for Ce+BAF

A baseline concept for a continuous wave (CW) polarized positron injector was developed for the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. This concept is based on the generation of CW longitudinally polarized positrons by a high-current, polarized electron beam (1 mA, 130‑370 MeV, and 90% longitudinal polarization) that passes through a rotating, water-cooled, tungsten target. The simulation results for the Ce+BAF injector at the Low Energy Recirculator Facility (LERF) are presented, including positron beam generation, capture, energy selection, and acceleration to 123 MeV. The positron yield (or positron current) and longitudinal polarization are calculated considering the longitudinal and transverse CEBAF acceptances (<1% energy spread, <1 mm bunch length and normalized emittance of <100 mm mrad). The impact of target thickness, drive electron beam energy, and transverse size on positron yield within the required emittance limit is evaluated.

Accelerator Physics↗
DOE OSTI2026

Positron Injector for Ce+BAF

A baseline concept for a continuous wave (CW) polarized positron injector was developed for the CEBAF at Jefferson Lab. This concept is based on the generation of CW longitudinally polarized positrons by a high-current, polarized electron beam 1 mA, 130-370 MeV, and 90% longitudinal polarization that passes through a rotating, water-cooled, tungsten target. The simulations for the Ce+BAF injector at the Low Energy Recirculator Facility (LERF) are performed, including positron beam generation, capture, energy selection, and acceleration to 123 MeV. The positron yield (or positron current) and longitudinal polarization are calculated considering the longitudinal and transverse CEBAF acceptances (<1% energy spread, 1.2 mm bunch length and normalized emittance of 100 mm·mrad). The impact of target thickness, electron beam energy, and transverse size on positron yield within the required emittance limit is evaluated. Target thermal and structural FEM analyses (ANSYS Fluent) are performed to determine the maximum electron beam current and minimum transverse beam size on the target.

Benesch, Jay [Thomas Jefferson National Accelerato↗
NASA NTRS2003

Solar Selective Coatings Prepared From Thin-Film Molecular Mixtures and Evaluated

Thin films composed of molecular mixtures of metal and dielectric are being considered for use as solar selective coatings for a variety of space power applications. By controlling molecular mixing during ion-beam sputter deposition, researchers can tailor the solar selective coatings to have the combined properties of high solar absorptance and low infrared emittance. On orbit, these combined properties simultaneously maximize the amount of solar energy captured by the coating and minimize the amount of thermal energy radiated. The solar selective coatings are envisioned for use on minisatellites, for applications where solar energy is used to power heat engines or to heat remote regions in the interior of the spacecraft. Such systems may be useful for various missions, particularly those to middle Earth orbit. Sunlight must be concentrated by a factor of 100 or more to achieve the desired heat inlet operating temperature. At lower concentration factors, the temperature of the heat inlet surface of the heat engine is too low for efficient operation, and at high concentration factors, cavity type heat receivers become attractive. The an artist's concept of a heat engine, with the annular heat absorbing surface near the focus of the concentrator coated with a solar selective coating is shown. In this artist's concept, the heat absorbing surface powers a small Stirling convertor. The astronaut's gloved hand is provided for scale. Several thin-film molecular mixtures have been prepared and evaluated to date, including mixtures of aluminum and aluminum oxide, nickel and aluminum oxide, titanium and aluminum oxide, and platinum and aluminum oxide. For example, a 2400- Angstrom thick mixture of titanium and aluminum oxide was found to have a solar absorptance of 0.93 and an infrared emittance of 0.06. On the basis of tests performed under flowing nitrogen at temperatures as high as 680 C, the coating appeared to be durable at elevated temperatures. Additional durability testing is planned, including exposure to atomic oxygen, vacuum ultraviolet radiation, and high-energy electrons.

Jaworske, Don A.↗
NASA NTRS2006

An Energetic Concept of Habitability for the Deep Subsurface

Universally, life must be characterized by a characteristic level of order and complexity. In the most general sense, habitability could then be defined as the set of factors required to allow the creation and maintenance of molecular complexity. These factors are: chemical raw materials; energy with which to assemble those materials into complex molecules and sustain the resultant state of complexity; a solvent that allows the interaction of complex molecules, promotes tertiary structure, and permits compartmentalization; and environmental conditions that permit the assembly and maintenance of complex molecules. On Earth, these general requirements correspond to the major biogenic elements C, H, O, N, P, S; chemical or light energy; the solvent water; and specific ranges of temperature, pH, radiation, ionic strength, and so forth, which have thus far been determined on and exclusively empirical basis. Importantly, while the complete absence of any of these factors ensures uninhabitable conditions, the mere presence of all four does not guarantee habitability. In each case - even that of water - it is a question of degree. This question can be couched in quantitative terms by considering the impact of each of these factors on cellular energy balance. More "extreme" conditions (e.g., high temperature, high or low pH, etc.), lower water activity, and low concentrations of nutrients incur or have potential to be addressed by increased investment of energy on the part of the cell. This must be balanced by energy conservation in the cell, noting that biochemical, mass transport, and abiotic chemical limitations intervene between environmental energy availability and biological energy capture. Similarly, lower boundary conditions are emplaced on useful environmental energy yields by the "quantized" nature of biological energy conservation, and upper boundary conditions are emplaced by energy levels or fluxes that are destructive with respect to complexity. This energetic framework, with boundary conditions supplied by the specifics of the biochemistry in question, offers a generalized, yet quantitative means of assessing the habitability of any system with respect to complex life.

Hoehler, Tori M.↗
NASA NTRS2020

Innovative Thermal Management & Control to Surmount Challenges of Exploring Ocean Worlds on Europa and Enceladus

Probes to penetrate the thick ice shells of our solar system’s Ocean Worlds have been studied for nearly 20 years, since scientific evidence strongly suggested a subsurface ocean on the Jupiter moon called Europa. There is keen scientific interest in exploring four significant themes on such proposed missions: 1) Geodynamics, 2) Geochemistry, 3) Habitability, and 4) Life Detection. The ice shells of Ocean Worlds are predicted to be up to 40 km thick; they exhibit extreme thermal environments, with ice temperatures from 100 K to 270 K, and extreme pressure environments from vacuum to 53 MPa. Jet Propulsion Laboratory has conducted a broad-look investigation of proposed mission concepts to Europa to identify the significant technology and operational challenges of Europa ice-penetration. The thermal-mechanical system (TMS) of an ice penetration probe (IPP) designed to access the ocean of an icy moon using radioisotope thermoelectric generators for heat and power faces technological hurdles exacerbated by severe thermal and volume constraints. This study identified thermal management and control (TMC) challenges that are strongly linked to: ice penetration start-up, mobility and navigation in the ice, communications while in the ice sheet, and detecting and avoiding in-ice hazards. The major objectives of the TMC system are: 1) Absorb internal thermal energy from the IPP radioisotope power source, 2) Maintain liquid water conditions around the IPP at all times, 3) Manage and control thermal flows from probe nose to tail, and 4) Provide pressure containment for all internal probe components. This work discusses the baseline TMC system architecture and design developed to accomplish these objectives, and survive and transit the extreme ice thicknesses in pursuit of Icy/Ocean Worlds science goals. The proposed TMC system consisting of an internal pumped two-phase fluid loop “thermal bus” for thermal energy capture, variable conductance heat pipe system for passively adaptive thermal energy transport around the probe, and water jetting system for ice cutting is described and discussed. Critical testing performed to date is described.

Lee, Kuan-Lin↗
NASA NTRS1981

Field limiter for solar radiometers

Lenses project solar image onto aperature to exclude circumsolar radiation, more precisely measuring energy captured by receiver aperatures of highly-concentrating solar thermal-energy converters. First version uses achromatic objective lens to form image of Sun at aperature ahead of radiometer cavity. Smaller second version with shorter focal length forms image magnified by another lens and thrown onto aperature. Both Versions require calibration against standard radiometer.

Berdahl, C. M.↗
DOE OSTI2022

Internal Reaction Mass Taxonomy and Narrow-Down Study

Internal reaction mass (IRM) wave energy converters (WEC) capture wave energy by reacting against a moving mass that is suspended within their hulls. Due to their hermetically sealed Power Take Off (PTO), compact form factor and relatively simple mooring requirements, the National Renewable Energy Laboratory has identified IRM WECs are good candidates for applications such as ocean observation. A literature review of existing IRM mechanisms lead to the classification of IRM WECs based on their principal method of energy capture and principal axes of operation. The IRM categories include sliding mass, pendular and gyroscopic devices. A narrow down study was conducted to ascertain the most promising mechanisms for further investigation; devices were evaluated based on a decision matrix of weighted criteria that included device power output, prototypability and power to mass ratio. The narrow down study identified the issue of achieving resonance with pendulum-based designs, as well as the poor response produced by reaction to long period waves. Chaotic pendula and methods to multiply agitation were identified as a means to increase power output. Alternative methods of power generation, such as triboelectric nanogenerators, were also identified as a technology that would benefit from multiplied agitation and chaotic motion. This work was funded under the U.S. Department of Energy's Water Power Technologies Office's Powering the Blue Economy portfolio.

ENGINEERING,TIDAL AND WAVE POWER↗
DOE OSTI2024

Transmissive concentrated photovoltaic module with cooling system

A spectrum splitting, transmissive concentrating photovoltaic (tCPV) module is proposed and designed for a hybrid photovoltaic-solar thermal (PV/T) system. The system may be able to fully utilize the full spectrum of incoming sunlight. By utilizing III-V triple junction solar cells with bandgaps of approximately 2.1 eV, 1.7 eV, and 1.4 eV in the module, ultraviolet (UV) and visible light (in-band light) are absorbed and converted to electricity, while infrared (IR) light (out-of-band light) passes through and is captured by a solar thermal receiver and stored as heat. The stored heat energy may be dispatched as electricity or process heat as needed. The tCPV module may have an overall power conversion efficiency exceeding 43.5% for above bandgap (in-band) light under a standard AM1.5D solar spectrum with an average concentration ratio of 400 suns. Passive and/or active cooling methods may be used to keep cells below 110° C. while transmitting >75% of out-of-band light to the thermal receiver, which may attain thermal energy capture at temperatures as high as 500° C. or more. A transparent active cooling system may improve the CPV module efficiency by about 1% (absolute) relative to a passive cooling system by reducing the maximum cell working temperature by about 16° C.

Escarra, Matthew David↗
DOE OSTI2023

Grand challenges in the digitalisation of wind energy

The availability of large amounts of data is starting to impact how the wind energy community works. From turbine design to plant layout, construction, commissioning, and maintenance and operations, new processes and business models are springing up. This is the process of digitalisation, and it promises improved efficiency and greater insight, ultimately leading to increased energy capture and significant savings for wind plant operators, thus reducing the levelised cost of energy. Digitalisation is also impacting research, where it is both easing and speeding up collaboration, as well as making research results more accessible. This is the basis for innovations that can be taken up by end users. But digitalisation faces barriers. This paper uses a literature survey and the results from an expert elicitation to identify three common industry-wide barriers to the digitalisation of wind energy. Comparison with other networked industries and past and ongoing initiatives to foster digitalisation show that these barriers can only be overcome by wide-reaching strategic efforts, and so we see these as “grand challenges” in the digitalisation of wind energy. They are, first, creating FAIR data frameworks; secondly, connecting people and data to foster innovation; and finally, enabling collaboration and competition between organisations. The grand challenges in the digitalisation of wind energy thus include a mix of technical, cultural, and business aspects that will need collaboration between businesses, academia, and government to solve. Working to mitigate them is the beginning of a dynamic process that will position wind energy as an essential part of a global clean energy future.

17 WIND ENERGY↗
DOE OSTI2026

Untapped Benefits of Porous Liquids for Gas Capture: Low-Energy Regeneration

Current liquid-phase gas capture materials incur high operational costs due to energy-intensive regeneration processes, creating an industrial need for alternative materials that retain engineering benefits while reducing energy requirements. Porous liquids (PLs), liquid-phase materials with permanent internal porosity, have emerged as promising replacements with excellent gas absorption capacity and selectivity. Despite these benefits, evaluation of regeneration in PLs remains rare. In this Perspective, we evaluate the effects of solvent interactions, mass transport, and binding site formation that control PL regeneration. While conventional regeneration methods exist in PLs, the diversity of PL compositions allows for novel regeneration processes including light irradiation via use of photosensitive azobenzene-based cages, isostatic compression to collapse internal pore structures, and localized heating via sonication for gas desorption. In conclusion, the wide variability in porous host materials that generate the internal porosity in PLs facilitates innovative low-energy regeneration pathways, positioning them as a transformative solution in separation technologies.

gas capture↗
DOE OSTI2023

Thrust-optimized blade design for wind turbines

A wind rotor is disclosed that produces energy optimally for a given thrust overturning moment. By designing rotors with suboptimal aerodynamic efficiency, they can have optimal thrust performance, which will reduce the substructure cost and/or enable greater energy capture for a given substructure.

17 WIND ENERGY↗
DOE OSTI2024

A Techno-Economic Analysis of a 50MWth Light-Trapping Cavity-Planar Solar Receiver Tower Capital Expenditures and its Cost Mitigation Strategies

To maximize thermal efficiency, the National Renewable Energy Laboratory (NREL) has proposed a light-trapping cavity-planar receiver design intended to capture energy from reradiating surfaces. This system implements a macroscale light trapping mechanism induced by panels with triangular channels, this mechanism allows for elevated temperatures on the receiver panels and in turn the temperature of the HTF; using this design coupled with the implementation of a fluidized particle flow as the HTF, it can be expected for some components to reach a peak working temperature of nearly 1000 degrees C cyclically throughout each day-night cycle. While these temperatures correlate to higher efficiency of the CSP tower they also demand intense thermomechanical properties from the materials used to make the receiver panels. In this analysis, we will list our assumptions to provide clarity on the significance of our calculation. This cost analysis will be conducted using a combination of both case study data and surveying industry to determine costs that are relevant to the current market trends. This analysis represents an early attempt to establish the Capital Expenditures required for a CSP tower of such design to determine the feasibility of implementing such a system in the industry.

concentrated solar power (CSP)↗
NASA NTRS2006

The role of invariant manifolds in lowthrust trajectory design (part III)

This paper is the third in a series to explore the role of invariant manifolds in the design of low thrust trajectories. In previous papers, we analyzed an impulsive thrust resonant gravity assist flyby trajectory to capture into Europa orbit using the invariant manifolds of unstable resonant periodic orbits and libration orbits. The energy savings provided by the gravity assist may be interpreted dynamically as the result of a finite number of intersecting invariant manifolds. In this paper we demonstrate that the same dynamics is at work for low thrust trajectories with resonant flybys and low energy capture. However, in this case, the flybys and capture are effected by continuous families of intersecting invariant manifolds.

low thrust trajectories↗
DOE OSTI2024

2022 Component Innovation Awardee: Pecos Wind Power

Distributed wind energy systems supply electricity for nearby homes and businesses, often in remote and rural regions. Systems capable of capturing energy in areas with low wind speeds make it possible to deploy these clean energy systems in many geographic locations. Pecos Wind Power's 85-kilowatt (kW) horizontal-axis PW85 wind turbine shows potential to reduce the levelized cost of energy by approximately 55% when compared to typical small wind systems while achieving utility-scale capacity factors of more than 40% in areas with lower wind speeds. To maximize cost competitiveness, the Pecos Wind Power turbine needs a blade optimized for low wind speeds. Through its 2022 Competitiveness Improvement Project (CIP) award, Pecos Wind Power and partner Wetzel Wind Energy Services will model, optimize, fabricate, and validate a 14.5-meter wind turbine blade made specifically for these applications. Three prior CIP awards supported Pecos Wind Power's initial development of the PW85 turbine.

CIP↗
NASA NTRS2003

Plant Response to Microwaves at 2.45 GHz

One method of beaming to Earth energy captured by Space Solar Power (SSP) satellites is by using microwaves. Since microwaves are non-ioniz ing and of low energy they probably will have little or no direct eff ect (either long- or short-term) on terrestrial biota. This contentio n must to be proved however, before the public will accept a continuo us beam of microwaves being sent to the ground near populated areas or onto agricultural lands. To begin to address this question, an exper iment has been done that exposed an important agronomic plant speaes (alfalfa, Medicago sativa L.) to a continuous microwave beam at 2.45 GHz and from between 0.5 to 1.2 milli-watts per square centimeter. Th e hypothesis was that plants exposed to microwaves will be no differe nt from those control plants that were not exposed to microwaves. The microwaves were broadcast over a tray of mature, growing plants in the laboratory. The control plants were subjected to the same environme ntal conditions (light, temperature, soil and nutrients) minus the mi crowave exposure. Both populations of plants were watered as needed. As may be seen, the experiment was designed so that the only variable to which the test plants were subjected was microwave exposure. Prec ise, non-destructive measurements were taken of leaf chlorophyll concentration over the period of the experiment. Also measured were gross plant variables such as stem length, internodal distance, and, at the end of the experiment, above-ground biomass, both fresh and dry weig hts. Soil temperatures on bare soil and under the plant canopy were a lso measured. After seven weeks of exposure to microwaves there was n o sigruficant difference between control and test plant populations. A number of other plant/ microwave exposure studies will be discussed in this presentation. However, this experiment is one of the few publ ished examples of organisms being exposed to continuos microwave illu mination at one of the proposed SSP microwave frequencies and intensi ties.

Skiles, J. W.↗
DOE OSTI2021

2020 Component Innovation Awardee: Carter Wind Turbines

With support from the Competitiveness Improvement Project's Component Innovation Award, Carter Wind Energy aims to address the need for lower-cost, more-reliable distributed wind energy generation. The company plans to increase efficiency and improve the energy capture of its Carter Model 300 midsize, self-erecting wind turbine. This fact sheet provides an overview of Carter Wind Energy's project, how the company will achieve the goals of the award, and how the project fits within the overall Competitiveness Improvement Project.

CIP↗