Search NASA⌕ Search

SEARCH · Search NASA

Results for “Photovoltaic Modules”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Launch packaging options for the photovoltaic power module cargo element

The National Aeronautics and Space Administration recently embarked on the Space Station Freedom program, which will utilize the Shuttle Orbiter for transportation to orbit. This task will be accomplished with a number of flights over several years. Each flight is unique in terms of the hardware that is manifested and the method by which it is integrated to form viable cargo elements. Work Package 4 is responsible for the electric power system for Space Station Freedom, and was delegated the authority to develop a photovoltaic (PV) power module cargo element. The PV power module consists of several unique assemblies. The first of these is the combined solar array/beta gimbal assembly. The remaining assemblies form the single combined integrated equipment assembly for each PV power module. These three combined assemblies are packaged into a launch cradle to form the PV power module cargo element, which is placed in the cargo bay of the Shuttle Orbiter for transportation to orbit. Various constraints determine the packaging options for the three PV power module combined assemblies. The size and shape of the combined assemblies in relation to the Shuttle Orbiter cargo bay dimensions and other manifested hardware are ultimately a factor in determining the acceptable packaging schemes for the PV power module cargo element. Several packaging options for the PV power module cargo element are presented. These options are discussed in terms of their impact on the overall flight hardware manifest as determined by the various constraints.

Hoberecht, Mark A.↗
NASA NTRS1989

Review of the environmental effects of the Space Station Freedom photovoltaic power module

An overview is provided of the environment in the low Earth orbit (LEO), the interaction of this environment with the Photovoltaic (PV) Power system of the Space Station Freedom is reviewed, and the environmental programs are described that are designed to investigate the interactions of the LEO environment with the photovoltaic power system. Such programs will support and impact the design of the subsystems of the PV module in order to survive the design lifetime in the LEO natural and induced environment.

Nahra, Henry K.↗
NASA NTRS1989

Review of the environmental effects on the Space Station Freedom photovoltaic power module

An overview is provided of the environment in the low earth orbit (LEO), the interaction of this environment with the photovoltaic (PV) power system of the Space Station Freedom is reviewed, and the environmental programs are described that are designed to investigate the interaction of the LEO environment with the photovoltaic power system. Such programs will support and impact the design of the subsystems of the PV module in order to survive the design lifetime in the LEO natural and induced environment.

Nahra, Henry K.↗
NASA NTRS1991

Push Tester For Laminated Films

Small instrument used to measure brittleness of polymer film adhesively bonded to hard substrate. Penlike instrument has microball tip. Small pointer in slot on side of instrument used to calibrate and indicate spring force applied by point. Microball dents only small area of specimen. Such measurements used to measure rates of embrittlement in environmental tests of candidate laminated-film covers for photovoltaic modules. Not limited to transparent films; also used on opaque laminated films on back panels of photovoltaic modules.

Sugimura, Russell S.↗
DOE OSTI2026

Measuring the Stress Factors for Photovoltaic (PV) Backsheet Degradation

Back sheet failure has resulted in power loss and large-scale recall of photovoltaic modules, resulting in billions of dollars in lost revenue. The light exposure on the backside of a photovoltaic module comes primarily from reflected light which alters the distribution of natural sunlight. Because of this, modelling the backside exposure and duplicating the exposure is much more difficult than modeling the frontside exposure. This project aims to study how various back sheets and junction box materials degrade under different conditions and to develop Python code to help model and predict degradation. The stress factors for back-sheet degradation must be quantified to extrapolate accelerated stress tests to the field. Test samples were placed in the A3, A4, and A5 conditions, as defined in IEC 62788-7-2, to assess the temperature and humidity dependence of ultraviolet (UV) induced degradation. We are utilizing a custom chamber with exposure from 0.5 UV-suns to 5 UV-suns to understand the dependence of degradation on light intensity. A group of samples put in the A3 condition had glass filters with 50% UV cut-offs of 320 nm, 335 nm, and 360 nm to assess the wavelength dependence of UV degradation. All this data is necessary to assess the impact of non-standard UV light exposure. The material evaluation tests include gloss measurements, attenuated total internal reflectance Fourier transform infrared spectroscopy (ATR-FTIR), UV-visible reflectance/transmittance utilizing a Cary Ci7000 spectrophotometer, and a nano-indenter for surface hardness and modulus measurements. Alongside the experimental work, there is a computational effort using raytracing and Python open-source tools in PVDeg , PVLib, and Bifacial_Radiance. This code will create specific exposure scenarios and enable the evaluation of chamber degradation relative to field degradation. Equation 1 is a strawman equation used to model degradation on the backside of a PV module. We will create simplified code, based on the results of ray-tracing calculations, which uses a view factor approach to provide fast calculations for the most common exposure scenarios.

14 SOLAR ENERGY↗
NASA NTRS1986

Tests of Solar-Array Encapsulants

Materials tested for degradation by heat and light. Report presents early results of continuing series of photothermal aging tests of some candidate encapsulating materials for solar photovoltaic modules. Objectives of testing program: contribute to development of durable, low-cost encapsulants and predict lifetimes of encapsulated photovoltaic modules placed outdoors. Toward these ends, tests designed to reveal physical and chemical degradation mechanisms that affect encapsulants.

Liang, R. H.↗
NASA NTRS1985

Development of design criteria and qualification tests for bypass diodes in photovoltaic applications

Design criteria have been developed for bypass diodes in p-n and Schottky barrier in photovoltaic applications. A test method for assessing conformity to the design criteria is described. Junction temperatures are defined in terms of expected worst-case field conditions, including ambient temperature and solar irradiance on the photovoltaic module. The rating criteria address the maximum allowable current and heat-sink characteristics of diodes mounted inside or outside the photovoltaic module. The method establishes worst-case module-to-diode thermal interfaces and may be adapted for laboratory or field-site experiments. A list of the design criteria is given.

Otth, D. H.↗
NASA NTRS1984

Intermediate load modules for test and evaluation

Photovoltaic modules were tested for qualification. Tests involved the following: (1) delivery of 20 solar cells for use as reference cells; (2) module documentation and inspection plans specifying the 10 Group I modules; (3) design review of module documentation from Group I modules; (4) revise module documentation to overcome any problems of deficiencies associated with the Group I modules; (5) delivery of 10 Group II modules built to revised specifications; (6) testing of Group II modules to the criteria as outlined in qualification specification. It is found that the solarvolt MSP43E40B satisfies the design criteria of qualification specification for intermediate load modules. Design changes were made in the Group I modules to overcome the deficiencies which allowed Group II modules to pass the qualification tests.

Source record↗
NASA NTRS1978

Simulated hail impact testing of photovoltaic solar panels

Techniques used to simulate and study the effect of hail on photovoltaic solar panels are described. Simulated hail stones (frozen ice spheres projected at terminal velocity) or steel balls were applied by air guns, gravity drop, or static loading. Tests with simulated hail and steel balls yielded different results. The impact strength of 10 commercially available flat-plate photovoltaic modules was tested. It was found that none of the six panel designs incorporating clear potting silicone material as the outermost layer remained undamaged by 1-in. simulated hailstones, while a photovoltaic module equipped with a 0.188-in.-thick acrylic cover sheet would be able to withstand the impact of a 2-in.-diameter hailstone.

Moore, D.↗
NASA NTRS1982

Empirical testing of an analytical model predicting electrical isolation of photovoltaic models

A major design requirement for photovoltaic modules is that the encapsulation system be capable of withstanding large DC potentials without electrical breakdown. Presented is a simple analytical model which can be used to estimate material thickness to meet this requirement for a candidate encapsulation system or to predict the breakdown voltage of an existing module design. A series of electrical tests to verify the model are described in detail. The results of these verification tests confirmed the utility of the analytical model for preliminary design of photovoltaic modules.

Garcia, A., III↗
NASA NTRS1983

Design, analysis and test verification of advanced encapsulation systems

The analytical methodology for advanced encapsulation designs for the development of photovoltaic modules is presented. Analytical models are developed to test optical, thermal, electrical and structural properties of the various encapsulation systems. Model data is compared to relevant test data to improve model accuracy and develop general principles for the design of photovoltaic modules.

Garcia, A., III↗
NASA NTRS1984

Electrical research on solar cells and photovoltaic materials

The flat-plate solar cell array program which increases the service lifetime of the photovoltaic modules used for terrestrial energy applications is discussed. The current-voltage response characteristics of the solar cells encapsulated in the modules degrade with service time and this degradation places a limitation on the useful lifetime of the modules. The most desirable flat-plate array system involves solar cells consisting of highly polarizable materials with similar electrochemical potentials where the cells are encapsulated in polymers in which ionic concentrations and mobilities are negligibly small. Another possible mechanism limiting the service lifetime of the photovoltaic modules is the gradual loss of the electrical insulation characteristics of the polymer pottant due to water absorption or due to polymer degradation from light or heat effects. The mechanical properties of various polymer pottant materials and of electrochemical corrosion mechanisms in solar cell material are as follows: (1) electrical and ionic resistivity; (2) water absorption kinetics and water solubility limits; and (3) corrosion characterization of various metallization systems used in solar cell construction.

Orehotsky, J.↗
NASA NTRS1981

A quantitative method for photovoltaic encapsulation system optimization

It is pointed out that the design of encapsulation systems for flat plate photovoltaic modules requires the fulfillment of conflicting design requirements. An investigation was conducted with the objective to find an approach which will make it possible to determine a system with optimum characteristics. The results of the thermal, optical, structural, and electrical isolation analyses performed in the investigation indicate the major factors in the design of terrestrial photovoltaic modules. For defect-free materials, minimum encapsulation thicknesses are determined primarily by structural considerations. Cell temperature is not strongly affected by encapsulant thickness or thermal conductivity. The emissivity of module surfaces exerts a significant influence on cell temperature. Encapsulants should be elastomeric, and ribs are required on substrate modules. Aluminum is unsuitable as a substrate material. Antireflection coating is required on cell surfaces.

Garcia, A., III↗
NASA NTRS1983

Breakdown of organic insulators

Solar cells and their associated electrical interconnects and leads were encapsulated in transparent elastomeric materials. Their purpose in a photovoltaic module, one of the most important for these elastomeric encapsulation materials, is to function as electrical insulation. This includes internal insulation between adjacent solar cells, between other encapsulated electrical parts, and between the total internal electrical circuitry and external metal frames, grounded areas, and module surfaces. Catastrophic electrical breakdown of the encapsulant insulation materials or electrical current through these materials or module edges to external locations can lead to module failure and can create hazards to humans. Electrical insulation stability, advanced elastomeric encapsulation materials are developed which are intended to be intrinsically free of in-situ ionic impurities, have ultralow water absorption, be weather-stable (UV, oxygen), and have high mechanical flexibility. Efforts to develop a method of assessing the life potential of organic insulation materials in photovoltaic modules are described.

Cuddihy, E. F.↗
NASA NTRS1982

Design, analysis and test verification of advanced encapsulation systems

An analytical methodology for advanced encapsulation designs was developed. From these methods design sensitivities are established for the development of photovoltaic module criteria and the definition of needed research tasks. Analytical models were developed to perform optical, thermal, electrical and analyses on candidate encapsulation systems. From these analyses several candidate systems were selected for qualification testing. Additionally, test specimens of various types are constructed and tested to determine the validity of the analysis methodology developed. Identified deficiencies and/or discrepancies between analytical models and relevant test data are corrected. Prediction capability of analytical models is improved. Encapsulation engineering generalities, principles, and design aids for photovoltaic module designers is generated.

Garcia, A., III↗
NASA NTRS1978

High efficiency solar photovoltaic power module concept

The investigation of a preliminary concept for high efficiency solar power generation in space is presented. The concept was a synergistic combination of spectral splitting, tailored bandgap cells, high concentration ratios, and cool cell areas.

Bekey, I.↗
NASA NTRS1986

Crystalline-silicon photovoltaics summary module design and reliability

The evolution of the design and reliability of solar modules was described. Design requirements involved 14 different considerations, including residential building and material electrical codes, wind-loading, hail impact, operating temperature levels, module flammability, and interfaces for both the array structure and the operation of the system. Reliability research involved in diverse investigations including glass-fracture strength, soiling levels, electrochemical corrosion, and bypass-diode qualification tests. Based on these internationally recognized studies, performance assessments, and failure analyses, the Flat-plate Solar Array Project in its 11-year duration served to nuture the development of 45 different solar module designs from 15 PV manufacturers.

Ross, R. G., Jr.↗
NASA NTRS1989

A definition study of the on-orbit assembly operations for the outboard photovoltaic power modules for Space Station Freedom

A concept is described for the assembly of the outboard PV modules for Space Station Freedom. Analysis of the on-orbit assembly operations was performed using CADAM design graphics software. A scenario for assembly using the various assembly equipment, as currently defined, is described in words, tables and illustrations. This work is part of ongoing studies in the area of space station assembly. The outboard PV module and the assembly equipment programs are all in definition and preliminary design phases. An input is provided to the design process of assembly equipment programs. It is established that the outboard PV module assembly operations can be performed using the assembly equipment currently planned in the Space Station Freedom Program.

Sours, Thomas J.↗