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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 OSTI2021

On the Ambiguity of Using Isc for Analyzing Suns-Voc Data on Modules

In standard silicon solar modules, cells are strung in series with bypass diodes incorporated to reduce the effects of shading. When all of the strings are partially shaded the measured short circuit current is affected and the Isc of the module will be equal to that of the lowest current cell in the least shadowed string. In bifacial modules the ability to assess losses due to shading is especially important. This paper advocates an alternative approach to converting the raw suns-voc data to pseudo IV data in modules where shading may be affecting the suns-voc curve results.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2021

CO 2 electrolysis to multicarbon products in strong acid

Carbon dioxide electroreduction (CO 2 R) is being actively studied as a promising route to convert carbon emissions to valuable chemicals and fuels. However, the fraction of input CO 2 that is productively reduced has typically been very low, <2% for multicarbon products; the balance reacts with hydroxide to form carbonate in both alkaline and neutral reactors. Acidic electrolytes would overcome this limitation, but hydrogen evolution has hitherto dominated under those conditions. We report that concentrating potassium cations in the vicinity of electrochemically active sites accelerates CO 2 activation to enable efficient CO 2 R in acid. We achieve CO 2 R on copper at pH <1 with a single-pass CO 2 utilization of 77%, including a conversion efficiency of 50% toward multicarbon products (ethylene, ethanol, and 1-propanol) at a current density of 1.2 amperes per square centimeter and a full-cell voltage of 4.2 volts.

Huang, Jianan Erick↗
DOE OSTI2023

Photovoltaics at multi-terawatt scale: Waiting is not an option

We report a major renewable-energy milestone occurred in 2022: Photovoltaics (PV) exceeded a global installed capacity of 1 TW dc . But despite considerable growth and cost reduction over time, PV is still a small part of global electricity generation (4 to 5% for 2022), and the window is increasingly closing to take action at scale to cut greenhouse gas (GHG) emissions while meeting global energy needs for the future. PV is one of very few options that can be dispatched relatively quickly, but discussions of TW-scale growth at the global level may not be clearly communicating the needed size and speed for renewable-energy installation. A major global risk would be to make poor assumptions or mistakes in modeling and promoting the required PV deployment and industry growth and then realize by 2035 that we were profoundly wrong on the low side and need to ramp up manufacturing and deployment to unrealistic or unsustainable levels.

14 SOLAR ENERGY↗
DOE OSTI2024

Contactless Production Testing of Silicon Solar Cells

Critical cost reductions in silicon solar cells are made by minimizing silver usage in their metal contacts. The reason why is both clear and unavoidable—silver is not only expensive, but also a potential limiting resource for scale-up (the PV industry alone used 10.3 % of the global silver supply in 2020 [1]). The result is solar cells with vanishing electrical contact area that are extremely difficult to test prior to module manufacture, when they must be sorted for quality to maximize power output and reliability of the subsequent modules. This project developed a new measurement instrument that enables the transition to solar cells with very low silver content, including cell designs with both minimal busbars and no busbars at all to electrically contact. The resulting instrument at project completion demonstrated the ability to sort cells with comparable—or better—results than existing technology. Compared to existing cell-test instruments, the new tool has minimal contacting requirements, which lowers the maintenance costs and use of consumable parts. We demonstrated innovative, yet pragmatic, solutions for reporting a comprehensive set of measurement results useful for both cell sorting (going forward in the line for module manufacture) and process control (looking backward in the line to identify cell manufacturing issues from wafer to cell-test). In addition to the traditional current-voltage characterization at cell test—short circuit current, open-circuit voltage, power, efficiency and fill factor—the new tool maintains all the advanced parameter characterization of our existing product line such as a substrate doping measurement, carrier recombination (lifetime) analysis, and surface recombination analysis.

14 SOLAR ENERGY↗
DOE OSTI2026

Leveling-Up for Big-Format Modules

Like Mario grabbing a super mushroom, PV modules just keep getting bigger! As they grow, so do the challenges of handling, installing, and testing them in the field. At NREL, we've embarked on our own New Hope - adapting to this size revolution across our tools, transportation, ergonomics, and field compatibility. Join us as we navigate this galactic expansion and keep PV testing at the cutting edge.

14 SOLAR ENERGY↗
NASA NTRS1972

Limb and polar brightening of Uranus at 8870 A.

Photographs of Uranus in the 8870 A band of methane exhibit limb brightening and brightening at the south pole. The polar brightening is explained by an upper atmospheric haze in addition to Rayleigh scattering by the upper atmosphere. An estimate of the geometric albedo at this wavelength yields a value near 0.01.

Sinton, W. M.↗
NASA NTRS1973

A high-resolution Fourier Transform Spectrometer for planetary spectroscopy

The employment of a high-resolution Fourier Transform Spectrometer (FTS) is described for planetary and other astronomical spectroscopy in conjunction with the 88-inch telescope at Mauna Kea Observatory. The FTS system is designed for a broad range of uses, including double-beam laboratory spectroscopy, infrared gas chromatography, and nuclear magnetic resonance spectroscopy. The data system is well-suited to astronomical applications because of its great speed in acquiring and transforming data, and because of the enormous storage capability of the magnetic tape unit supplied with the system. The basic instrument is outlined 2nd some of the initial results from the first attempted use on the Mauna Kea 88-inch telescope are reported.

Cruikshank, D. P.↗
NASA NTRS1972

A near-infrared view of the Uranus system.

An image intensifying tube placed at the f/10 Cassegrain focus of an 88-in. reflector telescope was used together with a narrow filter centered at the 8870-A methane band to obtain near-infrared photographs of Uranus and its satellites. Good images of Uranus were obtained with a 1-min exposure, while the faintest satellite Miranda was well recorded in about one hour. The short-exposure photograph of Uranus shows that the limb is brighter than the center of the disk and brightest at the south pole. The explanation for the brightening of the limb and pole seems to be haze in the planet's upper atmosphere.

Sinton, W. M.↗
NASA NTRS1973

Does Io have an ammonia atmosphere

A number of anomalous or discordant observations of Io can be explained if this Jovian satellite has an atmosphere containing ammonia. Such an atmosphere will be frozen at the unilluminated pole during the solstices, but will evaporate at the equinoctial seasons. The ammonia atmosphere will explain (1) the posteclipse brightenings and their observed times of occurrence and nonoccurrence; (2) the observed departure from a two-layer model heating curve upon emergency from the eclipse; (3) the discordant temperatures obtained at 10 and 20 micrometers; and (4) discordant temperatures obtained at 10 and 20 micrometers during the total phase of an eclipse by Jupiter.

Sinton, W. M.↗
NASA NTRS1976

Pressure-induced absorption by H2 in the atmospheres of Jupiter and Saturn

Observations of the S(1) line of the pressure-induced fundamental band of H2 in the spectra of Saturn and Jupiter are analyzed by comparing the observed line shape with predictions of both a reflecting-layer model and a homogeneous-scattering model of the atmospheres. Upper and lower limits are derived for the values of relative intensity that occur between 5000 and 5100 kaysers, the percent absorption due to H2 at 5100 kaysers is estimated, and it is established that methane and ammonia cannot account for the broad absorption attributed to hydrogen. The comparison with the model atmospheres shows that the reflecting-layer model appears to give the best fit to the Saturn line profile for temperatures near 150 K, while both models provide good fits to the Jupiter data, but for widely differing temperatures. Difficulties encountered in determining the true continuum level, especially for Jupiter, are discussed.

Martin, T. Z.↗
NASA NTRS1977

The brightness temperatures of Saturn and its rings at 39 microns

The relative rings-to-disk brightness (specific intensity) of Saturn at 39 microns was resolved using a 224-cm telescope, and the total flux of Saturn relative to Jupiter in the same bandpass was measured from the NASA Learjet Observatory. These two measurements, which were made with Saturn's rings near maximum inclination, determine the disk and average ring (A and B) brightness in terms of an absolute flux calibration of Jupiter in the same bandpass. While present uncertainties in Jupiter's absolute calibration make it impossible to compare existing measurements unambiguously, it is nevertheless possible to conclude the following: (1) observations between 20 and 40 microns are all compatible (within 2 sigmas) with a disk brightness temperature of 94 K and do not agree with the radiative equilibrium models of Trafton (1967); (2) the rings at large tilt contribute a flux component comparable to that of the planet itself for wavelengths not exceeding about 40 microns; and (3) there is a decrease of approximately 22% in the relative ring:disk brightness between effective wavelengths of 33.5 and 39 microns.

Nolt, I. G.↗
NASA NTRS1977

Uranus - The rings are black

An investigation is conducted concerning the possibility that the rings about Uranus discovered during the occultation of star SAO 158687 might have been observed in earlier studies of the planet. It is concluded that in view of a very low estimate for the contrast of the rings seen against the disk, a detection of the rings by earlier visual observers is unlikely. It appears, however, that the Stratoscope II photographs recorded the projection of the rings on the disk of Uranus.

Sinton, W. M.↗
NASA NTRS1979

Modular solar-heating system - design package

Compilation contains design, performance, and hardware specifications in sufficient detail to fabricate or procure materials and install, operate, and maintain complete modular solar heating and hot water system for single family size dwellings.

Sinton, D. S.↗
NASA NTRS1980

Io's 5 micron variability

An outburst of Io, similar to that observed by Witteborn, Bregman, and Pollack, has been observed with M filter-band photometry. At the beginning of observing on 1979 June 11 (UT) the flux was about 3 times its normal value and decayed approximately linearly with time by 23% in the first hour of observing. The beginning of observations followed the emergence of Io from eclipse by 1.5 hours.

Sinton, W. M.↗