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Results for “reference solar cells”

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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Study of flywheel energy storage for space stations

The potential of flywheel systems for space stations using the Space Operations Center (SOC) as a point of reference is discussed. Comparisons with batteries and regenerative fuel cells are made. In the flywheel energy storage concept, energy is stored in the form of rotational kinetic energy using a spinning wheel. Energy is extracted from the flywheel using an attached electrical generator; energy is provided to spin the flywheel by a motor, which operates during sunlight using solar array power. The motor and the generator may or may not be the same device. Flywheel energy storage systems have a very good potential for use in space stations. This system can be superior to alkaline secondary batteries and regenerable fuel cells in most of the areas that are important in spacecraft applications. Of special impotance relative to batteries, are high energy density (lighter weight), longer cycle and operating life, and high efficiency which minimizes the amount of orbital makeup fuel required. In addition, flywheel systems have a long shelf life, give a precise state of charge indication, have modest thermal control needs, are capable of multiple discharges per orbit, have simple ground handling needs, and have the potential for very high discharge rate. Major disadvantages are noted.

Gross, S.↗
NASA NTRS1986

Development of ultrastable filters and lasers for solar seismology

The Stable Solar Analyzer is a recently developed instrument for the measurement of solar magnetic fields and surface velocities that is being employed at the U.S. National Solar Observatory to study the subsurface convection cells of the sun and the structure of surface and subsurface magnetic fields. The Analyzer is expected to ultimately be flown aboard such spacecraft as the ESA/NASA Solar and Heliospheric Observatory. This instrument is based on a crystalline lithium niobate Fabry-Perot filter that is used in conjunction with a stabilized laser that furnishes an absolute wavelength reference; this laser Fabry-Perot combination has achieved wavelength stabilities of the order of 2 parts in 10 to the 10th, over a six-hour interval.

Rust, D. M.↗
NASA NTRS1986

Proposal for superstructure based high efficiency photovoltaics

A novel class of cascade structures is proposed which features multijunction upper subcells, referred to as superstructure high-efficiency photovoltaics (SHEPs). The additional junctions enhance spectral response and improve radiation tolerance by reducing bulk recombination losses. This is important because ternary III-V alloys, which tend to have short minority-carrier diffusion lengths, are the only viable materials for the high-bandgap upper subcells required for cascade solar cells. Realistic simulations of AlGaAs SHEPs show that one-sun AM0 efficiencies in excess of 26 percent are possible.

Wagner, M.↗
NASA NTRS1993

Results of the 1993 NASA/JPL balloon flight solar cell calibration program

The 1993 solar cell calibration balloon flight was completed on July 29, 1993. All objectives of the flight program were met. Forty modules were carried to an altitude of 120,000 ft (36.6 km). Data telemetered from the modules was corrected to 28 C and to 1 AU. The calibrated cells have been returned to 8 participants and can now be used as reference standards in simulator testing of cells and arrays.

Anspaugh, B. E.↗
NASA NTRS1992

Results of the 1992 NASA/JPL Balloon Flight Solar Cell Calibration Program

The 1992 solar cell calibration balloon flight was completed on August 1, 1992. All objectives of the flight program were met. Forty-one modules were carried to an altitude of 119,000 ft (36.3 km). Data telemetered from the modules was corrected to 28 C and 1 AU. The calibrated cells have been returned to 39 participants and can now be used as reference standards in simulator testing of cells and arrays.

Anspaugh, B. E.↗
NASA NTRS1991

Results of the 1991 NASA/JPL balloon flight solar cell calibration program

The 1991 solar cell calibration balloon flight was completed on August 1, 1991. All objectives of the flight program were met. Thirty-nine modules were carried to an altitude of 119,000 ft. (36.3 km). Data telemetered from the modules were corrected to 28 C and to 1 AU. The calibrated cells have been returned to the participants and can now be used as reference standards in simulator testing of cells and arrays.

Anspaugh, B. E.↗
DOE OSTI2023

Carbon Electrode with Sputtered Au Coating for Efficient and Stable Perovskite Solar Cells

Halide perovskite solar cells (PSCs) represent a low-cost and high-efficiency solar technology. However, most of the highly efficient PSCs need a noble electrode, such as Au, through thermal evaporation. Here it is reported that a sputtered Au electrode on a PSC could damage the organic hole transport layer (HTL) and the perovskite layer. Here, we report a simple, yet effective sputtered gold nanoparticle decorated carbon electrode to fabricate efficient and stable planar PSCs. The sputtered Au layer on the doctor-bladed coated carbon electrode can be directly applied to the perovskite semicells by mechanical stacking. By optimizing the gold thickness, a power conversion efficiency (PCE) of 16.87% was obtained for the composite electrode-based PSC, while the reference device recorded a PCE of 12.38%. The composite electrode-based device demonstrated 96% performance retention after being stored under humid conditions (50-60%) without encapsulation for ~100 h. This demonstrates a promising pathway toward the commercialization of large-scale manufacturable sputtered electrodes for the PSC solar module.

14 SOLAR ENERGY↗
NASA NTRS1981

Direct conversion of light to radio frequency energy

A description is presented of the test results obtained with the latest models of the phototron. The phototron was conceived as a replacement for the high voltage solar cell-high power klystron combination for the solar power satellite concept. Physically, the phototron is a cylindrical evacuated glass tube with a photocathode, two grids, and a reflector electrode in a planar configuration. The phototron can be operated either in a biased mode where a low voltage is used to accelerate the electron beam produced by the photocathode or in an unbiased mode referred to as self-oscillation. The device is easily modulated by light input or voltage to broadcast in AM or FM. The range of operation of the present test model phototrons is from 2 to 200 MHz.

Freeman, J. W.↗
NASA NTRS1994

Results of the 1994 NASA/JPL balloon flight solar cell calibration program

The 1994 solar cell calibration balloon flight was completed on August 6, 1994. All objectives of the flight program were met. Thirty-seven modules were carried to an altitude of 119,000 ft (36.6 km). Data telemetered from the modules was corrected to 28 C and to 1 AU. The calibrated cells have been returned to the 6 participants and can now be used as reference standards in simulator testing of cells and arrays.

Anspaugh, B. E.↗
DOE OSTI2020

Automotive fuel cell stack and system efficiency and fuel consumption based on vehicle testing on a chassis dynamometer at minus 18 °C to positive 35 °C temperatures

In this work we present an in-depth laboratory technology assessment of a 2016 Toyota Mirai Fuel Cell (FC) vehicle based on chassis dynamometer testing. The 114.6 kW FC stack has a high dynamic response, which makes this powertrain a FC-dominant hybrid electric vehicle. The measured peak efficiency is 66.0% FC stack and 63.7% FC system with an idle hydrogen flow rate of 4.39 g/hr. The high FC system efficiencies at low loads match typical vehicle power spectrums, resulting in a high average vehicle efficiency of 62% compared to 45% and 23% for a hybrid electric vehicle and a conventional vehicle, respectively. An energy breakdown accounts for the FC stack losses, FC system losses, air compressor loads, and heater loads for different drive cycles and different thermal conditions. The cold-start North American city drive cycle (UDDS) energy consumption values are, respectively, 758, 581, 226, and 321 Wh/km at ambient conditions of -18 degrees C, -7 degrees C, -25 degrees C and 35 degrees C with 850 W/m 2 of solar loading. The FC system shutdown and startup processes at temperatures below the freezing point contribute to the increased hydrogen consumption. Additionally, the raw test data files are available for download, thus providing the research community with a public reference data on a modern production automotive FC system.

08 HYDROGEN↗
NASA NTRS1990

Results of the 1990 NASA/JPL balloon flight solar cell calibration program

The 1990 solar cell calibration balloon flight consisted of two flights, one on July 20, 1990 and the other on September 6, 1990. A malfunction occurred during the first flight, which resulted in a complete loss of data and a free fall of the payload from 120,000 ft. After the tracker was rebuilt, and several solar cell modules were replaced, the payload was reflown. The September flight was successful and met all the objectives of the program. Forty-six modules were carried to an altitude of 118,000 ft (36.0 km). Data telemetered from the modules was corrected to 28 C and to 1 a.u. The calibrated cells have been returned to the participants and can now be used as reference standards in simulator testing of cells and arrays.

Anspaugh, Bruce E.↗
NASA NTRS1984

The Magneto-optical Filter, Working Principles and Recent Progress

The Magneto-Optical Filter is described which allows simultaneous magnetic and velocity measurements (in both imaging and non-imaging modes) without the need for a spectrograph. In this way the stability and alignment problems of the spectrograph are completely overcome. Its major advantages are: wavelength absolute reference and stability, high signal to noise ratio and independence of the transmission profile from the incidence angle of the solar beam. It is an imaging instrument allowing high wave number analysis in the solar oscillation spectrum and a continuous monitoring of the image position through the chromospheric facular structures. The apparatus in use at Mt. Wilson is assembled in a modular form. The most important part of it is a glass cell containing the sodium vapor. The filter is easy to use but the cell is not easy to construct in an optimal way. The technology is in progress both to use Na and K together and to prevent the windows from becoming coated during a long-term operation.

Cacciani, A.↗
NASA NTRS1990

Power system requirements and definition for lunar and Mars outposts

Candidate power systems being considered for outpost facilities (stationary power systems) and vehicles (mobile systems) are discussed, including solar, chemical, isotopic, and reactor. The current power strategy was an initial outpost power system composed of photovoltaic arrays for daytime energy needs and regenerative fuel cells for power during the long lunar night. As day and night power demands grow, the outpost transitions to nuclear-based power generation, using thermoelectric conversion initially and evolving to a dynamic conversion system. With this concept as a guideline, a set of requirements has been established, and a reference definition of candidate power systems meeting these requirements has been identified.

Petri, D. A.↗
NASA NTRS2009

Regenerative Performance of the NASA Symmetrical Solid Oxide Fuel Cell Design

The NASA Glenn Research Center is developing both a novel cell design (BSC) and a novel ceramic fabrication technique to produce fuel cells predicted to exceed a specific power density of 1.0 kW/kg. The NASA Glenn cell design has taken a completely different approach among planar designs by removing the metal interconnect and returning to the use of a thin, doped LaCrO3 interconnect. The cell is structurally symmetrical. Both electrodes support the thin electrolyte and contain micro-channels for gas flow-- a geometry referred to as a bi-electrode supported cell or BSC. The cell characteristics have been demonstrated under both SOFC and SOE conditions. Electrolysis tests verify that this cell design operates at very high electrochemical voltage efficiencies (EVE) and high H2O conversion percentages, even at the low flow rates predicted for closed loop systems encountered in unmanned aerial vehicle (UAV) applications. For UAVs the volume, weight and the efficiency are critical as they determine the size of the water tank, the solar panel size, and other system requirements. For UAVs, regenerative solid oxide fuel cell stacks (RSOFC) use solar panels during daylight to generate power for electrolysis and then operate in fuel cell mode during the night to power the UAV and electronics. Recent studies, performed by NASA for a more electric commercial aircraft, evaluated SOFCs for auxiliary power units (APUs). System studies were also conducted for regenerative RSOFC systems. One common requirement for aerospace SOFCs and RSOFCs, determined independently in each application study, was the need for high specific power density and volume density, on the order of 1.0 kW/kg and greater than 1.0 kW/L. Until recently the best reported performance for SOFCs was 0.2 kW/kg or less for stacks. NASA Glenn is working to prototype the light weight, low volume BSC design for such high specific power aerospace applications.

Cable, Thomas L.↗
DOE OSTI2023

The Baseline Performance Reference for Irradiance in PV System Applications

This report proposes the definition of a new baseline performance reference (BPR). The definition goes beyond existing standards pertaining to photovoltaic (PV) reference cells and devices to define the response under all possible operating conditions in the field. Field evaluations using BPR devices will be more sensitive to performance anomalies than pyranometers because they track PV system power output more closely. At the same time, they will be able to detect a broader range of performance anomalies than traditional matched reference devices, which might have matching defects. The BPR definition also opens the door to new practices in resource assessment and yield prediction. Solar resource data can be collected or modeled and validated directly as BPR irradiance, and PV system simulations based on BPR irradiance need fewer assumptions and less processing to obtain the effective irradiance on modules. As a result, lower uncertainty in yield assessments can be expected.

14 SOLAR ENERGY↗
DOE OSTI2022

2,3-Diphenylthieno[3,4-b]pyrazines as Hole-Transporting Materials for Stable, High-Performance Perovskite Solar Cells

High-performance and durable perovskite solar cells (PSCs) have advanced rapidly, enabled in part by the development of superior interfacial hole-transporting layers (HTLs). Here, in this study, a new series of 2,3-diphenylthieno[3,4-b]pyrazine (DPTP)-based small molecules containing bis- and tetrakis-triphenyl amino donors (1–3) was synthesized from simple, low-cost, and readily available starting materials. The matched energy levels, ideal surface topographies, high hole mobilities of 8.57 × 10 –4 cm 2 V –1 S –1 , and stable chemical structures of DPTP-4D (3) make it an effective hole-transporting material, delivering a PCE of 20.18% with high environmental, thermal, and light-soaking stability when compared to the reference HTL materials, doped Spiro-OMeTAD and PTAA in PSC n-i-p planar devices. Overall, these DPTP-based molecules are promising HTM candidates for the fabrication of stable PSCs.

14 SOLAR ENERGY↗
NASA NTRS1991

A preliminary design for a satellite power system

Outlined here is a preliminary design for a Solar Power Satellite (SPS) system. The SPS will provide a clean, reliable source of energy for mass consumption. The system will use satellites in geostationary orbits around the Earth to capture the sun's energy. The intercepted sunlight will be converted to laser beam energy which can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting to one ground station. The SPs technology uses multi-layer solar cell technology arranged on a 20 sq km planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Construction will take place in low Earth orbit and array sections, 20 in total, will be sailed on the solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing panels (SSAPs). The primary truss elements used to support the arrays are composed on composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

Enriquez, Clara V.↗
DOE OSTI2022

A Decoupled Droop Control Strategy for Cascaded Multicell Inverter with Low-Frequency Modulation

Cascaded multicell inverter (CMI), featured by its merits of modularity and fault-tolerance, is suitable for medium-voltage applications without using bulky step-up transformers. However, little research has reported grid-forming control of the CMI for the application in the power grid with high penetrations of inverter-interfaced generation. To bridge this research gap, this paper proposes a novel droop control strategy for the CMI with a low-frequency modulation to offer inertia and reactive power support to the power grid. A decoupled Q/V droop control strategy is proposed to eliminate the coupling effect from the P/ω control loop caused by the phase-angle difference between the voltages of the CMI and the grid. The output of the Q/V control loop is set as the reference voltage for each cell of the CMI, which makes the CMI naturally a voltage source to provide a grid-forming capability. Finally, the proposed control strategy shows great active and reactive power regulation and sharing capability, which is validated by simulation on two 100 kW, 2.4 kV CMIs connected in parallel to a power grid.

14 SOLAR ENERGY↗