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Sugimura, R. S.

Publications and source records attributed to Sugimura, R. S..

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Lessons Learned From the Flight of the NASA In-Step Cryo System Experiment

The Cryo System Experiment (CSE), a NASA In-Space Technology Experiments Program (IN- STEP) Flight Experiment, was developed by Hughes Aircraft Company under contract to the Jet Propulsion Laboratory (JPL) to validate in near zero-g space a 65 K cryogenic system for focal planes, optics, instruments, or other equipment (gamma-ray spectrometers, and infrared and submillimeter imaging instruments) that require continuous cryogenic cooling.

NASA↗
NASA NTRS1994

Lessons Learned During the Integration Phase of the NASA IN-STEP Cryo System Experiment

The Cryo System Experiment (CSE), a NASA In-Space Technology Experiments Proram (IN-STEP) Class D Flight Experiment, was developed by Hughes Aircraft Company (Hughes) to validate in zero-g space a 65 K cryogenic system for focal planes, optics, instruments, or other equipment (gramma-ray spectrometers and infrared and submillimeter imaging instruments) that require continuous cryogenic cooling.

cryogenic launch-vibration restraints thermal stra↗
NASA NTRS1989

Hotspot Endurance Of Solar-Cell Modules

Procedure for evaluating modules for use with concentrators now available. Solar simulator illuminates photovoltaic cells through Fresnel lens of concentrator module. Module and test cells inspected visually at 24-h intervals during test and again when test completed. After test, electrical characteristics of module measured for comparison with pretest characteristics.

Gonzalez, C. C.↗
NASA NTRS1988

Electrical isolation design and electrochemical corrosion in thin-film photovoltaic modules

The development of a proposed wet insulation-resistance qualification test specification for production-line modules is presented. Laboratory research directed toward understanding and eliminating problems associated with electrical isolation of thin-film photovoltaic module circuitry is presented. Test results serve to measure module field life as limited by electrochemical corrosion degradation mechanisms. Current module-level research covering encapsulant voltage withstand capability is also described, and suggestions for improving module electrical isolation are offered.

Sugimura, R. S.↗
NASA NTRS1987

Hot-spot qualification testing of concentrator modules

Results of a study to determine the hot-spot susceptibility of concentrator cells, to provide a hot-spot qualification test for concentrator modules, and to provide guidelines for reducing hot-spot susceptibility are presented. Hot-spot heating occurs in a photovoltaic module when the short-circuit current of a cell is lower than the string operating current, forcing the cell into reverse bias with a concurrent power dissipation. Although the basis for the concentrator-module hot-spot qualification test is the test developed for flat-plate modules, issues such as providing cell illumination introduce additional complexities into the testing procedure. The results indicate that the same general guidelines apply to protecting concentrator modules from hot-spot stressing as apply to flat-plate modules, and recommendations are made on the number of bypass diodes required per given number of series cells per module or source circuit. A method for determining the cell temperature in the laboratory or in the field is discussed.

Gonzalez, C. C.↗
NASA NTRS1985

Electrical safety requirements: Implications for the module designer

Commercial photovoltaic array installations, which include residential and intermediate applications, are subject to building and electrical codes and to product safety standards. The National Electrical Code (NEC) Article 690, titled Solar Photovoltaic Systems, contains provisions defining acceptable levels of system safety and emphasizes the system design and its installation. The Underwriters Laboratories, Inc. (UL), document titled: Proposed First Edition of the Standard for Flat Plate Photovoltaic Modules and Panels, UL-1703, identifies module and panel construction requirements that ensure product safety. Together these documents describe requirements intended to minimize hazards such as shock and fire. Although initial focus of these requirements is on single crystal silicon modules, they are generic in nature, and are equally applicable to high voltage ( 30 Vdc), multikilowatt, thin film systems. A major safety concern is insulation breakdown within the module or array wiring system, or discontinuities within the electrical conductors. These failures can result in ground faults, in circuit arcs, or exposure to hazardous electrical parts. Safeguards are discussed.

Sugimura, R. S.↗
NASA NTRS1985

Module flammability research

New materials were developed which show promise of fabricating modules that can pass the Underwriter Laboratories Class A burning brand test for fire ratable solar cell modules. It is concluded that fire resistant module design require special high temperature materials and constructions to achieve Class B and Class A ratings. Also, synergisms exist between back surface materials and module configuration.

Sugimura, R. S.↗
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 NTRS1985

Development and testing of advanced fire-resistant photovoltaic modules

The evaluation of back-surface materials flammability in order to identify fire resistant module designs is examined. The fire test apparatus, burning-brand test sequence, and spread-of-flame test sequence are described. Video recordings and time-temperature profiles of module back surfaces are utilized to study the flammability failure mechanism and identify high-temperature materials. A table of flammability test results for various module designs is provided. The data reveals that 2-mil kapton, fiberglass cloth coated or impregnated with a material to plug pores, and metal foil back-surface materials achieve class A and B fire-resistance levels, and are applicable for photovoltaic module designs.

Sugimura, R. S.↗
NASA NTRS1985

Candidate materials for advanced fire-resistant photovoltaic modules

A cooperative, cost-sharing research effort to develop a technology base required to construct fire-ratable photovoltaic modules has resulted in the identification of several high-temperature, back-surface candidate materials capable of raising the fire-resistance of modules using hydrocarbon encapsulants to Class A and B levels. Advanced experimental module configurations have been developed using back surfaces consisting of Kapton, Tedlar laminates, metal-foils, and fiberglass materials with high-temperature coatings. Test results (October 1984; March 1985; May 1985; and October 1985) indicate that several of these advanced module configurations are capable of achieving Class B fire-resistance levels, while a few configurations can achieve Class A levels. The paper summarizes activities to date, discussing flammability failure mechanisms, time-temperature profiles, and results of Block V environmental exposure tests of a candidate material suitable for both Class B and Class A fire-resistance levels.

Sugimura, R. S.↗
NASA NTRS1984

Photovoltaic module spread-of-flame testing

Photovoltaic modules used in solar energy conversion are tested for flammability. Class B burning brand tests were conducted with the following results: module glass shattered and hydrocarbon encapsulants ignited. Penetration of back surface material was the prime cause of failure. Materials with greater flame and heat resistance are under consideration to increase back surface integrity up to Class A burning brand standard. The most promising is stainless steel foil.

Sugimura, R. S.↗
NASA NTRS1984

Flammability of photovoltaic modules

A series of Class B burning-brand tests were performed on experimental modules using high-temperature, back-surface materials to develop the technology base required to construct fire-ratable modules. Results indicate the existence of synergistic relationships between hydrocarbon encapsulation materials and the experimental module configurations that provide increased fire resistance. These configurations use Kapton, fiberglass, neoprene rubber, stainless-steel foil or aluminum foil as the back surface. Successful test results occur when the structural integrity of the module back surface is maintained. Test failures of these modules always occur for one of three reasons: the outermost back cover melts, rips, or is too porous. In each case flammable molten encapsulant, its gaseous byproducts, or both, penetrates the back surface of the module and bursts into flame. Future efforts to complete the technology base will concentrate on the spread-of-flame test, focusing on the more promising configurations identified in the initial series of tests.

Sugimura, R. S.↗
NASA NTRS1984

The integration of bypass diodes with terrestrial photovoltaic modules and arrays

Bypass diodes are often required to limit the potential for reverse voltage 'hot-spot' heating in high voltage arrays or in arrays that undergo periodic operation near the short-circuit point. In addition, when properly applied, bypass diodes can minimize the effect of shadowing and various internal module failures on the array energy output. This paper discusses the mechanical and electrical integration of bypass diodes beginning with the array-level considerations which influence the selection of an implementation approach. Concepts for the mounting of these diodes, both internally within the module encapsulant and externally to the exposed rear surface of the module, are described. Factors affecting the reliability of bypass diodes, including the control of junction temperature through adequate heat sinking and the derating of reverse voltage, are discussed.

Shepard, N. F., Jr.↗