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Results for “Dual Use Solar”

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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Navigation system design for a Halley Flyby/Tempel 2 Rendezvous mission using ion drive

A dual comet (Hall Flyby/Tempel 2 Rendezvous) mission, making use of the solar electric propulsion system, is under consideration for a 1985 launch. This paper describes the preliminary navigation system design for this mission. Orbit determination and guidance strategies for each mission phase are discussed. Navigation accuracy analyses and parametric senstivity studies for the Tempel 2 rendezvous approach phase are presented.

Wood, L. J.↗
NASA NTRS1980

Navigation accuracy analysis for the Halley flyby phase of a dual comet mission using ion drive

A dual comet (Halley Flyby/Tempel 2 Rendezvous) mission, making use of the solar electric propulsion system, is under consideration for a 1985 launch. This paper presents navigation accuracy analysis results for the Halley flyby phase of this mission. Orbit determination and guidance accuracies are presented for the baseline navigation strategy, along with the results of a number of sensitivity studies involving parameters such as data frequencies, data accuracies, ion drive thrust vector errors, comet ephemeris uncertainties, time lags associated with data processing and command sequence generation, probe release time, and navigation coast arc duration.

Wood, L. J.↗
NASA NTRS2005

Design and Development of the Space Technology 5 (ST5) Solar Arrays

The National Aeronautics and Space Administration's (NASA's) Space Technology 5 (ST5) is designed to flight-test the concept of miniaturized 'small size" satellites and innovative technologies in Earth's magnetosphere. Three satellites will map the intensity and direction of the magnetic fields within the inner magnetosphere. Due to the small area available for the solar arrays, and to meet the mission power requirements, very high-efficiency multijunction solar cells were selected to power the spacecraft built by NASA Goddard Space Flight Center (GSFC). This was done in partnership with the Air Force Research Lab (AFRL) through the Dual-Use Science and Technology (DUS&T) program. Emcore's InGaP/lnGaAs/Ge Advanced triple-junction (ATJ) solar cells, exhibiting an average air mass zero (AMO) efficiency of 28.0% (one-sun, 28 C), were used to populate the arrays. Each spacecraft employs 8 identical solar panels (total area of about 0.3 square meters), with 15 large-area solar cells per panel. The requirement for power is to support on-orbit average load of 13.5 W at 8.4 V, with plus or minus 5% off pointing. The details of the solar array design, development and qualification considerations, as well as ground electrical performance & shadowing analysis results are presented.

Lyons, John↗
NASA NTRSDate not supplied

STEREO Observations of Stream Interaction Regions in 2007-2016:Relationship with Heliospheric Current Sheets, Solar Cycle Variations, and Dual Observations

We have conducted a survey of 575 slow-to-fast stream interaction regions (SIRs) using STEREOA/B data in 2007-2016 (Jian et al., 2019). Among 518 well-defined SIRs, 54% are associated with heliospheric current sheet (HCS) crossings, and 34% are without any HCS crossing. The other 12% of the SIRs often occur in association with magnetic sectors shorter than 3 days. The SIRs with HCS crossings have slightly slower speeds but higher maximum number densities, magnetic field strengths, dynamic pressures, and total pressures than the SIRs without an HCS. The iron charge state is higher throughout the SIRs with an HCS than the SIRs without an HCS, by about 1/3 charge unit. In contrast with the comparable phases of solar cycle 23,slightly more SIRs and higher recurrence rates are observed in the years 2009-2016 of cycle 24,with a lower HCS association rate, possibly attributed to persistent equatorial coronal holes and more pseudostreamers in this recent cycle. The solar wind speed, peak magnetic field and pressures of SIRs are all lower in this cycle, but the weakening is less than for the comparable background solar wind parameters. Before STEREO B lost contact in 2014 October, 151 SIR pairs were observed by the twin spacecraft. Of the dual observations, the maximum speed is the best correlated of the plasma parameters. We have obtained a sample of plasma parameter differences analogous to those that would be observed for a mission at Lagrange point 4 or 5.By studying several cases with large discrepancies between the dual observations, we have also investigated the effects of HCS relative location, tilt of stream interface, and small transients on the SIR properties.

Lan K Jian↗
DOE OSTI2019

Continuous on-sun solar thermochemical hydrogen production via an isothermal redox cycle

Solar thermochemical hydrogen production from water is a path towards a carbon-free sustainable hydrogen economy. Here, isothermal on-sun hydrogen production is demonstrated using active iron aluminate (hercynite) particles contained in dual fluidized bed reactors. The two fluidized beds were held in a single cavity solar receiver that was heated with a 10 kW high flux solar furnace. During 8 h of on-sun testing, 5.3 L of H 2 were generated with an average productivity of 597 umol H 2 /g using an intermittent process with optimized redox cycle times. Redox cycling was performed isothermally and continuously with equivalent oxidation and reduction times producing 547 umol H2/g over two cycles. These results show excellent agreement with the H 2 production measured in an 800X scaled-down electrically heated laboratory stagnation flow reactor and surpass on-sun H 2 production of current benchmark materials. The effect of environmental variability on the incident solar radiation and hydrogen production is evaluated during on-sun testing. Finally, a discussion of the important factors for scalability of the process to commercial applications is provided, highlighting the importance of robust containment and active materials. This work links current materials research and development with commercial implementation in an on-sun process and demonstrates the viability of solar thermochemical hydrogen production that leverages continuous isothermal redox cycling.

08 HYDROGEN↗
DOE OSTI2015

Enhanced conversion efficiency in wide-bandgap GaNP solar cells

In this study, we demonstrate –2.05 eV dilute nitride GaNP solar cells on GaP substrates for potential use as the top junction in dual-junction integrated cells on Si. By adding a small amount of N into indirect-bandgap GaP, GaNP has several extremely important attributes: a direct-bandgap that is also tunable, and easily attained lattice-match with Si. Our best GaNP solar cell ([N] –1.8%, E g –2.05 eV) achieves an efficiency of 7.9%, even in the absence of a window layer. This GaNP solar cell's efficiency is 3× higher than the most efficient GaP solar cell to date and higher than other solar cells with similar direct bandgap (InGaP, GaAsP). Through a systematic study of the structural, electrical, and optical properties of the device, efficient broadband optical absorption and enhanced solar cell performance are demonstrated.

14 SOLAR ENERGY↗
DOE OSTI2020

High Efficiency Inverted GaAs and GaInP/GaAs Solar Cells With Strain-Balanced GaInAs/GaAsP Quantum Wells

High-efficiency solar cells are essential for high-density terrestrial applications, as well as space and potentially vehicle applications. The optimum bandgap for the terrestrial spectrum lies beyond the absorption range of a traditional dual junction GaInP/GaAs cell, with the bottom GaAs cell having higher bandgap energy than necessary. Lower energy bandgaps can be achieved with multiple quantum wells (QWs), but such a pathway requires advanced management of the epitaxial growth conditions in order to be useful. Strain-balanced GaAsP/GaInAs QWs are incorporated into a single junction GaAs solar cell and a dual junction GaInP/GaAs solar cell, leading to 27.2% efficiency in the single junction device and a one-sun record 32.9% efficiency in the tandem device. Good carrier collection and low non-radiative recombination are observed in the cells with up to 80 QWs. The GaAs cells employ a rear-heterojunction architecture to boost the open-circuit voltage to over 1.04 V in the quantum well device, despite the large number of QWs.

14 SOLAR ENERGY↗
DOE OSTI2022

Chapter 2: Evaluating a Concentrating Solar Power Plantas an Extended-Duration Peaking Resource

We explore the ability of a concentrating solar power (CSP) plant with thermal energy storage (TES) to provide peaking capacity. We focus on future power systems, wherein net load patterns may be significantly different than they are today (e.g., due to higher renewable-energy penetrations). We examine 28 locations in the southwestern United States over an 18-year period. The hourly operation of the CSP plants are simulated to determine their potential to provide energy during an eight-hour peak-load window for each day up to 365 days per year. Our result shows that for the large majority of locations and years, CSP plants with certain configurations (i.e., in terms of solar field and TES sizes) can provide nearly 100% peak-load capacity. We examine also the amount of supplemental energy (e.g.,by using natural gas as a supplemental thermal-energy source) that would be required to ensure that a CSP plant could serve the eight highest-load hours of every day of the year. We find that in most cases, a CSP plant supplemented with natural gas would require less than 5% of the fuel that is used by a natural-gas fired power plant providing the same level of reliable capacity. A series of sensitivity analyses show that these results are robust to the number of peak-load hours and days that are considered and the configuration of the CSP plant.

capacity value↗
NASA NTRS2006

Stretched Lens Array (SLA) for Collection and Conversion of Infrared Laser Light: 45% Efficiency Demonstrated for Near-Term 800 W/kg Space Power System

For the past 2% years, our team has been developing a unique photovoltaic concentrator array for collection and conversion of infrared laser light. This laser-receiving array has evolved from the solar-receiving Stretched Lens Array (SLA). The laser-receiving version of SLA is being developed for space power applications when or where sunlight is not available (e.g., the eternally dark lunar polar craters). The laser-receiving SLA can efficiently collect and convert beamed laser power from orbiting spacecraft or other sources (e.g., solar-powered lasers on the permanently illuminated ridges of lunar polar craters). A dual-use version of SLA can produce power from sunlight during sunlit portions of the mission, and from beamed laser light during dark portions of the mission. SLA minimizes the cost and mass of photovoltaic cells by using gossamer-like Fresnel lenses to capture and focus incoming light (solar or laser) by a factor of 8.5X, thereby providing a cost-effective, ultra-light space power system.

O'Neill, Mark↗
NASA NTRS1984

The Spectrophotometric Method of Determining the Transmission of Solar Energy in Salt Gradient Solar Ponds

In order to predict the thermal efficiency of a solar pond it is necessary to know total average solar energy reaching the storage layer. One method for determining this energy for water containing dissolved colored species is based upon spectral transmission measurements using a laboratory spectrophotometer. This method is examined and some of the theoretical ground work needed to discuss the measurement of transmission of light water. Results of in situ irradiance measurements from oceanography research are presented and the difficulties inherent in extrapolating laboratory data obtained with ten centimeter cells to real three dimensional pond situations is discussed. Particular emphasis is put on the need to account for molecular and particulate scattering in measurements done on low absorbing solutions. Despite these considerations it is expected that attenuation calculations based upon careful measurements using a dual beam spectrophotometer technique combined with known attenuation coefficients will be useful in solar pond modeling and monitoring for color buildup. Preliminary results using the CSM method are presented.

Giulianelli, J.↗
NASA NTRS1980

Solar energy system performance evaluaton: Seasonal report for Solaron-Akron, Akron, Ohio

The operational and thermal performance of the solar energy system by Solaron Corporation is described. The system was designed to provide an 1940 square foot floor area with space heating and domestic hot water for a dual-level single family residence in Akron, Ohio. The solar energy system uses air as the heat transport medium, has a 546 square foot flat plate collector array subsystem, a 270 cubic foot rock thermal storage bin subsystem, a domestic hot water preheat tank, pumps, controls and transport lines. In general, the performance of the Solaron Akron solar energy system was somewhat difficult to assess for the November 1978 through October 1979 time period. The problems relating to the control systems, various solar energy leakages, air flow correction factors and instrumentation cause a significant amount of subjectivity to be involved in the performance assessment for this solar energy system. Had these problems not been present, it is felt that this system would have exhibited a resonably high level of measured performance.

Source record↗
DOE OSTI2014

General volume sizing strategy for thermal storage system using phase change material for concentrated solar thermal power plant

With an auxiliary large capacity thermal storage using phase change material (PCM), Concentrated Solar Power (CSP) is a promising technology for high efficiency solar energy utilization. In a thermal storage system, a dual-media thermal storage tank is typically adopted in industry for the purpose of reducing the use of the heat transfer fluid (HTF) which is usually expensive. While the sensible heat storage system (SHSS) has been well studied, a dual-media latent heat storage system (LHSS) still needs more attention and study. The volume sizing of the thermal storage tank, considering daily cyclic operations, is of particular significance. In this paper, a general volume sizing strategy for LHSS is proposed, based on an enthalpy-based 1D transient model. One example was presented to demonstrate how to apply this strategy to obtain an actual storage tank volume. With this volume, a LHSS can supply heat to a thermal power plant with the HTF at temperatures above a cutoff point during a desired 6 hours of operation. This general volume sizing strategy is believed to be of particular interest for the solar thermal power industry.

14 SOLAR ENERGY↗
DOE OSTI2024

Agrivoltaics: Solar Farming for a Greener Future

Resilient, secure, diversified, and disaster-hardened energy systems are critical to Puerto Rico's clear energy future. This presentation builds on NREL's PR100 One Year Progress Summary Report, discussing the intersection of land availability, PV capacity growth, and the potential role of agrivoltaics in contributing to Puerto Rico's 100% renewable energy goal and agricultural sector resilience. An overview of the state-of-the-science in agrivoltaics is provided, including the NREL InSPIRE Puerto Rican pilot project on hurricane-resistant, shade-grown agrivoltaic coffee. Agrivoltaics is discussed in the context of food-energy resilience for island nations, and future research & development needs are highlighted.

agrivoltaics↗
NASA NTRS1972

Solar electric low-thrust Mercury orbiter missions.

Results of a preliminary study of unmanned Mercury orbiter missions which might be flown in the early 1980s. Five different levels of orbiter size and complexity are considered, ranging from a small orbiter carrying 22 kg of low data-rate instruments to a dual satellite mission employing 110 kg of science instruments emphasizing regional and local scale surface imagery. An Intermediate-20 class launch vehicle is required to deliver a minimal surface-imaging science package into Mercury orbit using a ballistic mission mode. Employment of a 15 kW solar electric low-thrust stage permits delivery of the more capable dual satellite package with a Titan IIID (5)/Centaur.

Klopp, D. A.↗
NASA NTRS2009

Problems Encountered During the Recertification of the GLORY Solar Array Dual Axis Gimbal Drive Actuators

The Glory observatory is the current incarnation of the Vegetation Canopy Lidar (VCL) mission spacecraft bus. The VCL spacecraft bus, having been cancelled for programmatic reasons in 2000, was nearly integrated when it was put into storage for possible future use. The Glory mission was a suitable candidate for using this spacecraft and in 2006 an effort to recertify the two axis solar array gimbal drive after its extended storage was begun. What was expected to be a simple performance validation of the two dual axis gimbal stepper motors became a serious test, diagnosis and repair task once questions arose on the flight worthiness of the hardware. A significant test program logic flow was developed which identified decisions that could be made based on the results of individual recertification tests. Without disassembling the bi-axial gimbals, beginning with stepper motor threshold voltage measurements and relating these to powered drive torque measurements, both performed at the spacecraft integrator s facility, a confusing picture of the health of the actuators came to light. Tests at the gimbal assembly level and tests of the disassembled actuators were performed by the manufacturer to validate our results and torque discrepancies were noted. Further disassembly to the component level of the actuator revealed the source of the torque loss.

Saltzman, Marc↗
DOE OSTI2025

A Dual-Mode Hybrid System Combining Solar Thermal With Pumped Thermal Energy Storage

A hybrid system that delivers renewable electricity generation and electricity storage capabilities is introduced. This dual-mode hybrid system is based on Pumped Thermal Energy Storage (PTES) which uses a heat pump to convert electricity into thermal energy that is trans-ferred to silica particles which are stored in concrete silos. The stored heat is later converted back to electricity in a heat engine. The heat pump and heat engine use a closed Joule-Brayton cycle and fluidized bed heat exchangers. If the PTES system is co-located with an array of concentrating solar mirrors and a particle receiver, then the silica particles may also be heated up by the concentrating solar power (CSP) system. The PTES heat engine may also be used to convert the stored solar heat into electricity, thereby sharing this system between the PTES and CSP systems and reducing costs. However, this requires careful management of the heat engine off-design parameters. A thermodynamic model is used to evaluate the performance of the dual mode PTES-CSP hybrid system. The model accounts for turbomachinery effi-ciency, and approach temperature and pressure loss in heat exchangers, as well as other sources of inefficiency, such as motor-generator losses, and air fan power. The hybrid system also requires the evaluation of the turbomachinery efficiency and pressure ratio at off-design conditions since the CSP system operates over different temperature ratios than the Carnot Battery. Several design variables and design modifications are investigated, such as pressure ratios and maximum temperatures.

14 SOLAR ENERGY↗
DOE OSTI2024

Unraveling radiation damage and healing mechanisms in halide perovskites using energy-tuned dual irradiation dosing

Perovskite photovoltaics have been shown to recover, or heal, after radiation damage. Here, we deconvolve the effects of radiation based on different energy loss mechanisms from incident protons which induce defects or can promote efficiency recovery. We design a dual dose experiment first exposing devices to low-energy protons efficient in creating atomic displacements. Devices are then irradiated with high-energy protons that interact differently. Correlated with modeling, high-energy protons (with increased ionizing energy loss component) effectively anneal the initial radiation damage, and recover the device efficiency, thus directly detailing the different interactions of irradiation. We relate these differences to the energy loss (ionization or non-ionization) using simulation. Dual dose experiments provide insight into understanding the radiation response of perovskite solar cells and highlight that radiation-matter interactions in soft lattice materials are distinct from conventional semiconductors. These results present electronic ionization as a unique handle to remedying defects and trap states in perovskites.

14 SOLAR ENERGY↗
NASA NTRS2015

Novel Materials, Processing, and Device Technologies for Space Exploration with Potential Dual-Use Applications

We highlight results of a broad spectrum of efforts on lower-temperature processing of nanomaterials, novel approaches to energy conversion, and environmentally rugged devices. Solution-processed quantum dots of copper indium chalcogenide semiconductors and multi-walled carbon nanotubes from lower-temperature spray pyrolysis are enabled by novel (precursor) chemistry. Metal-doped zinc oxide (ZnO) nanostructured components of photovoltaic cells have been grown in solution at low temperature on a conductive indium tin oxide substrate. Arrays of ZnO nanorods can be templated and decorated with various semiconductor and metallic nanoparticles. Utilizing ZnO in a more broadly defined energy conversion sense as photocatalysts, unwanted organic waste materials can potentially be re-purposed. Current efforts on charge carrier dynamics in nanoscale electrode architectures used in photoelectrochemical cells for generating solar electricity and fuels are described. The objective is to develop oxide nanowire-based electrode architectures that exhibit improved charge separation, charge collection and allow for efficient light absorption. Investigation of the charge carrier transport and recombination properties of the electrodes will aid in the understanding of how nanowire architectures improve performance of electrodes for dye-sensitized solar cells. Nanomaterials can be incorporated in a number of advanced higher-performance (i.e. mass specific power) photovoltaic arrays. Advanced technologies for the deposition of 4H-silicon carbide are described. The use of novel precursors, advanced processing, and process studies, including modeling are discussed from the perspective of enhancing the performance of this promising material for enabling technologies such as solar electric propulsion. Potential impact(s) of these technologies for a variety of aerospace applications are highlighted throughout. Finally, examples are given of technologies with potential spin-offs for dual-use or terrestrial applications.

thin films↗