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  • Other Sources  (496)
  • ENERGY PRODUCTION AND CONVERSION  (496)
  • 2010-2014
  • 1980-1984  (496)
  • 1925-1929
  • 1982  (496)
  • 1
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    On the cause of the flat-spot phenomenon observed in silicon solar cells at low temperatures and low intensities (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A model that explains the flat-spot power loss phenomenon is presented. Evidence suggests that the effect is due to localized metallurgical interactions between the silicon substrate and the contact metallization. These reactions are shown to result in localized regions in which the P-N junction is destroyed and replaced with a metal semiconductor-like interface. The effects of thermal treatment, crystallographic orientation, junction depth, and metallization are shown along with a method of preventing the effect through the suppression of vacancy formation at the free surface of the contact metallization. Data indicating the effectiveness of a TiN diffusion barrier in preventing the effect are also given.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 65-70
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  • 2
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    NASA solar array flight experiment (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The NASA large flexible solar array space shuttle flight experiment is described. The 32 x 4 m wing is deployed from the shuttle bay, and experiments in electrical output, multiple deployment, and structural dynamics are planned. Both 2 x 4 cm and 5.9 x 5.9 cm cell assemblies on the array blanket are evaluated. Safety/hazards provisions are described, including emergency jettison provisions. Ground testing and hardware fabrication are summarized.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 179-184
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  • 3
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    Large area low-cost space solar cell development (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A development program to produce 5.9 x 5.9 cm space quality silicon solar cells with a cost goal of 30 $/W is described. Cell types investigated include wraparound dielectric, mechanical wraparound and conventional contact configurations with combinations of 2 or 10 ohm/cm resistivity, back surface reflectors and/or fields, and diffused or ion implanted junctions. A single step process to cut cell and cover glass simultaneously is being developed. Results for cell and array tests are given. Large solar arrays that might use cells of this type are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 23-26
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  • 4
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    The swing to concentrator arrays (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Objectives and progress in both low concentration ratio (6 to 10) and high concentration ratio ( 100) array developments are summarized. Problems encountered include: thermal control, maldistribution of concentrated sunlight, current busing, and optical surface degradation. The potential advantages over planar arrays are an order of magnitude reduction in per unit cost of power plus increased immunity to radiation damage.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p xix-xxiv
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  • 5
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    Determination of optimum sunlight concentration level in space for 3-5 cascade solar cells (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Current-voltage curves were calculated for each cell in a cascade structure using a solar cell diode equation and superposition. Terms for the light generated current, diffusion current, space charge recombination current and series and shunt resistance are included. Individual current voltage curves are added in series with ohmic resistance losses for the cell interconnects to obtain the cascade cell performance. Temperature was varied with concentration, using several models, and ranged from 55 C at one Sun to between 80 and 200 C at 100 Suns. A variety of series resistance and internal resistances were used. Coefficients of the diffusion and recombination terms are strongly temperature dependent. The study indicates that maximum efficiency (30%) occurs in the 50 to 100X Sun concentration range, provided series resistance is below 0.015 ohm-sq cm and cell temperature is 80 C at 100 Suns.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 265-270
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  • 6
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    Effects of processing and dopant on radiation damage removal in silicon solar cells (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Gallium and boron doped silicon solar cells, processed by ion implantation followed by either laser or furnace anneal were irradiated by 1 MeV electrons and their postirradiation recovery by thermal annealing was determined. During the postirradiation anneal, gallium doped cells prepared by both processes recovered more rapidly and exhibited none of the severe reverse annealing observed for similarly processed 2 ohm-cm boron doped cells. Ion implanted furnace annealed 0.1 ohm-cm boron doped cells exhibited the lowest post-irradiation annealing temperatures after irradiation. The drastically lowered recovery temperature is attributed to the reduced oxygen and carbon content of the 0.1 ohm-cm cells. Analysis based on defect properties and annealing kinetics indicates that further reduction in annealing temperature is attainable with further reduction in the silicon's carbon and/or divacancy content after irradiation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 89-93
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  • 7
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    Design, installation and operating experience of 20 photovoltaic medical refrigerator systems on four continents (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The NASA Lewis Research Center in cooperation with the World Health Organization, U.S.A. I.D., the Pan American Health Organization and national government agencies in some developing countries sponsored the installation of twenty photovoltaic powered medical vaccine storage refrigerator-freezer (R/F) systems. The Solar Power Corporation was selected as the contractor to perform the design, development and installation of these twenty units. Solar Power's experiences are described herein.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 8
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    Development of a photovoltaic module qualification test based on combined-environment accelerated stress data (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The U.S. Coast Guard has developed a qualification test to screen photovoltaic modules for utilization on marine aids to navigation. The test is based on a combined-environment of hot and cold saltwater immersion and air pressurization. The test has demonstrated a very high acceleration factor and excellent correlation of electrical failures with modules in a concurrent real-time marine exposure.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 9
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    Design principles for high efficiency small-grain polysilicon solar cells, with supporting experimental studies (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Design principles suggested here aim toward high conversion efficiency (greater than 15 percent) in polysilicon cells. The principles seek to decrease the liabilities of both intragranular and grain-boundary-surface defects. The advantages of a phosphorus atom concentration gradient in a thin (less than 50 microns) base of a p(+)/n(x)/n(+) drift-field solar cell, which produces favorable gradients in chemical potential, minority-carrier mobility and diffusivity, and recombination lifetime (via phosphorus gettering) are suggested. The degrading effects of grain boundaries are reduced by these three gradients and by substituting atoms (P, H, F or Li) for vacancies on the grain-boundary surface. From recent experiments comes support for the benefits of P diffusion down grain boundaries and, for quasi-grain-boundary-free and related structures. New analytic solutions for the n(x)-base include the effect of a power-law dependence between P concentration and lifetime. These provide an upper-bound estimate on the open circuit voltage. Finite-difference numerical solutions of the six Shockley equations furnish complete information about all solar-cell parameters and add insight concerning design.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 10
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    Residential photovoltaic power conditioning technology for grid connected applications (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Major advances in photovoltaic (PV) Power Conditioning (PC) with respect to performance and low-cost potential have been made. Solutions have been obtained to interface and control problems related to adapting available inverter designs to the grid-connected, residential photovoltaic experiments. A description is presented to contributing research and development activities. Attention is given to aspects of residential systems experience, conceptual design studies, questions of optimum topology development, and promising advanced designs for residential PV provided by development efforts of the private sector.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 11
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    Design solutions for the solar cell interconnect fatigue fracture problem (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Mechanical fatigue of solar cell interconnects is a major failure mechanism in photovoltaic arrays. A comprehensive approach to the reliability design of interconnects, together with extensive design data for the fatigue properties of copper interconnects, has been published. This paper extends the previous work, developing failure prediction (fatigue) data for additional interconnect material choices, including aluminum and a variety of copper-Invar and copper-steel claddings. An improved global fatigue function is used to model the probability-of-failure statistics of each material as a function of level and number of cycles of applied strain. Life-cycle economic analyses are used to evaluate the relative merits of each material choce. The copper-Invar clad composites demonstrate superior performance over pure copper. Aluminum results are disappointing.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 12
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    Optimal design of high-efficiency tandem cells (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Computer analysis indicates that a substantial increase in solar cell conversion efficiencies can be achieved by using two-cell, multi-bandgap tandem structures instead of single-junction cells. Practical AM1 efficiencies of about 30 percent at one sun and over 30 percent at multiple suns are to be expected. The further increases in efficiency calculated for a three-cell tandem structure are much smaller and may not justify the added complexity. For inexpensive two-cell tandem modules, Si is preferred for the bottom cell, and the top-cell material should have a bandgap of 1.75 to 1.80 eV. The GaAs-AlAs and GaAs-GaP systems are very attractive candidates for the top cell. Significant advances have been achieved in growing GaAs on Ge-coated Si substrates (for the two-terminal, two-cell structure) and in growing free-standing ultrathin GaAs layers (for the two-terminal or four-terminal structures). These advances should be transferable to the GaAs-AlAs and GaAs-GaP systems.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 13
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    Characterization of the electrical output of flat-plate photovoltaic arrays (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The electric output of flat-plate photovoltaic arrays changes constantly, due primarily to changes in cell temperature and irradiance level. As a result, array loads such as direct-current to alternating-current power conditioners must be able to accommodate widely varying input levels, while maintaining operation at or near the array maximum power point.The results of an extensive computer simulation study that was used to define the parameters necessary for the systematic design of array/power-conditioner interfaces are presented as normalized ratios of power-conditioner parameters to array parameters, to make the results universally applicable to a wide variety of system sizes, sites, and operating modes. The advantages of maximum power tracking and a technique for computing average annual power-conditioner efficiency are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 14
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    Solar cell performance at low illumination and temperature for deep-space applications (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 12, p. 2037, Accession no. A81-29543)
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 15
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    Single crystal growth of upgraded metallurgical silicon by HEM for photovoltaic applications (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Commercially available metallurgical grade (MG) silicon has high B and P content which is not reduced significantly by directional solidification. By choosing high purity raw materials for an experimental Submerged Electrode Arc Furnace, most of the impurities are reduced to 10 ppmw. Directional solidification of upgraded metallurgical grade (UMG) silicon by the Heat Exchanger Method (HEM) has produced 16 cm x 16 cm cross section ingots with nearly single crystal structure. The main problem encountered during directional solidification was SiC impurities dispersed through the structure. Solar cells fabricated from UMG silicon that was directionally solidified twice by HEM have shown up to 12.33% (am1) conversion efficiency.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Silicon Ingot Casting, Phase 3 and Phase 4; 12 p
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  • 16
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    Origin of SiC impurities in silicon crystals grown from the melt in vacuums (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A main source of high carbon levels in silicon crystals grown from melt under reduced pressures and contained in silica crucibles supported by graphite retainer/susceptor was identified by thermodynamic analysis. The calculations were verified by experimental results and the carbon level is reduced by approximately 50% with the use of molybdenum retainers.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Crystal Systems, Inc. Silicon Ingot Casting, Phase 3 and Phase 4; 5 p
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  • 17
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    Silicon crystal growth in vacuum (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The most developed process for silicon crystal growth is the Czochralski (CZ) method which was in production for over two decades. In an effort to reduce cost of single crystal silicon for photovoltaic applications, a directional solidification technique, Heat Exchanger Method (HEM), was adapted. Materials used in HEM and CZ furnaces are quite similar (heaters, crucibles, insulation, etc.). To eliminate the cost of high purity argon, it was intended to use vacuum operation in HEM. Two of the major problems encountered in vacuum processing of silicon are crucible decomposition and silicon carbide formation in the melt.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Silicon Ingot Casting, Phase 3 and Phase 4; 4 p
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  • 18
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    Part 2: Multi-wire slicing. Fixed Abrasive Slicing Technique (FAST) (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Fixed Abrasive Slicing Techniques (FAST) is a new slicing technique that was developed to slice ingots more effectively. It was demonstrated that 25 wafers/cm can be sliced from 10cm diameter and 19 wafers/cm from 15 cm diameter ingots. Over 99% yield (222 out of a possible 224) was demonstrated during slicing of a 10 cm diameter ingots at 25 wafers/cm. The average thickness of wafers was 0.249 mm and the kerf was 0.151 mm. Slicing rates as high as 0.14 mm/min were also demonstrated for 10 cm diameter ingots.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Silicon Ingot Casting, Phase 3 and Phase 4; 67 p
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  • 19
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    Silicon slicing by fixed abrasive slicing technique (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: One of the major cost factors in silicon ingot technology adaptation for terrestrial photovoltaic application is in slicing boules into wafers. The most developed industrial practice is the Internal Diameter (ID) slicing. This method utilizes diamond cutting. The diamond stands up for long periods, hence, the cost of expendable materials is low. However, the ID technology as practiced today has poor material utilization. The Multiblade Slurry (MBS) method has low equipment and labor costs but its expendable material costs are high. Recently Multiwire Slurry (MWS) technology has shown very good material utilization, but its expendable material costs are even higher than MBS. The multiwire Fixed Abrasive Slicing Technique (FAST) still in advanced development stage, combines the low expendable material costs of ID method, the low labor and equipment costs of MBS and high material utilization of MWS.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Silicon Ingot Casting, Phase 3 and Phase 4; 3 p
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  • 20
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    Part 1: Silicon ingot casting. Heat Exchanger Method (HEM) (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Directional solidification by the Heat Exchanger Method (HEM) is a viable approach for directional solidification of silicon ingots used for terrestrial solar cell applications. Some of the significant advances made during this phase of the program were: ingot size, 34 cm x 34 cm x 17 cm - 45 kg, usable material yield - 90%, solar cell efficiency averaged over the whole ingot - 85% of control CZ (35 kg ingot), very uniform resistivity over the boule, and cycle time for 36 kg ingots - 56 hours. Some of the problems encountered were growth rate decrease with increased ingot height, silicon carbide precipitates, and high dislocation density in HEM material. The silicon carbide is attributed to backstreaming of oil vapors from the vacuum pump; the high dislocation density is associated with the thermal history of the boule.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Silicon Ingot Casting, Phase 3 and Phase 4; 111 p
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  • 21
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    An economic evaluation of solar energy (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The economic advantages of solar dish collectors are evaluated and compared with other energy systems. Labor, inflation and energy deregulation are considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Ann. Program Rev., Proc.; p 329-338
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  • 22
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    Potential benefits from a successful solar thermal program (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Solar energy systems were investigated which complement nuclear and coal technologies as a means of reducing the U.S. dependence on imported petroleum. Solar Thermal Energy Systems (STES) represents an important category of solar energy technologies. STES can be utilized in a broad range of applications servicing a variety of economic sectors, and they can be deployed in both near-term and long-term markets. The net present value of the energy cost savings attributable to electric utility and IPH applications of STES were estimated for a variety of future energy cost scenarios and levels of R&D success. This analysis indicated that the expected net benefits of developing an STES option are significantly greater than the expected costs of completing the required R&D. In addition, transportable fuels and chemical feedstocks represent a substantial future potential market for STES. Due to the basic nature of this R&D activity, however, it is currently impossible to estimate the value of STES in these markets. Despite this fact, private investment in STES R&D is not anticipated due to the high level of uncertainty characterizing the expected payoffs.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 295-318
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  • 23
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    Dish Stirling system integration and test progress report (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The integration and check-out of a complete Dish Solar Stirling Thermal Power System is described. The preliminary results of the tests conducted thus far are presented. The results are very encouraging and show promise of high performance and efficiency. The outstanding performance and durability of the 4-95 Stirling engine was the highlight of this 6 month integration and test activity. Exposure to severe heat, dust, sand and wind during the summer months and heavy rains, high winds, including sand storms and freezing cold in recent months did affected the engine or the receiver in any noticable manner.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 191-200
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  • 24
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    Recent tests on the Carter small reciprocating steam engines (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Jay Carter Enterprises (JCE) Paratransit Vehicle steam engine was tested over a range of conditions which might be experienced by the power converter subsystem of the Small Community Solar Thermal Power Experiment. Some difficulties were encountered getting the engine ready for testing. These difficulties were related to the five year dormancy of the entire system and to incomplete development work that had been going on at the time of cessation of steam engine work at JCE. Other difficulties were related to the fact that the particular expander being tested never ran before and possessed some manufacturing defects. Nevertheless, the engine was operated successfully and results of testing do verify results of computer simulations of the engine in regard to the effect of temperature and power level variations. Engine efficiency was good but generally lower than expected and performance dropped as testing continued. The effect of change in expansion ratio was not demonstrated because of deterioration in engine performance. Post-test inspection revealed numerous correctable defects.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 123-145
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  • 25
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    High-temperature ceramic heat exchanger element for a solar thermal receiver (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A study was performed by AiResearch Manufacturing Company, a division of The Garrett Corporation, on the development a high-temperature ceramic heat exchanger element to be integrated into a solar receiver producing heated air. A number of conceptual designs were developed for heat exchanger elements of differing configuration. These were evaluated with respect to thermal performance, pressure drop, structural integrity, and fabricability. The final design selection identified a finned ceramic shell as the most favorable concept. The shell is surrounded by a larger metallic shell. The flanges of the two shells are sealed to provide a leak-tight pressure vessel. The ceramic shell is to be fabricated by an innovative combination of slip casting the receiver walls and precision casting the heat transfer finned plates. The fins are bonded to the shell during firing. The unit is sized to produce 2150 F ar at 2.7 atm pressure, with a pressure drop of about 2 percent of the inlet pressure. This size is compatible with a solar collector providing a receiver input of 85 kw(th). Fabrication of a one-half scale demonstrator ceramic receiver has been completed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 233-246
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  • 26
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    Modifications and testing of a 4-95 Stirling engine for solar applications (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The modifications and testing of a standard Stirling engine, required for connection to a 25 kW induction alternator, for use with a solar thermal parabolic dish electric module is described. Power was absorbed by a GE induction alternator connected to the utility grid. Also included are the results from recent testing of another solar engine at the DOE-Georgia Tech solar site. It was done in parallel with the testing at Edwards for the purpose of comparing performance of two solar-only receivers, which were based on the standard 4-95 involute heat exchanger.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 179-189
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  • 27
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    Verification testing of the PKI collector at Sandia National Laboratories, Albuquerque, New Mexico (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Verification testing of a solar collector was undertaken prior to its operation as part of an industrial process heat plant at Capitol Concrete Products in Topeka, Kansas. Testing was performed at a control plant installed at Sandia National Laboratory, Albuquerque, New Mexico (SNLA). Early results show that plant performance is even better than anticipated and far in excess of test criteria. Overall plant efficiencies of 65 to 80 percent were typical during hours of good insolation. A number of flaws and imperfections were detected during operability testing, the most important being a problem in elevation drive alignment due to a manufacturing error. All problems were corrected as they occurred and the plant, with over 40 hours of operation, is currently continuing operability testing in a wholly-automatic mode.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 115-118
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  • 28
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    Organic Rankine power conversion subsystem development for the small community solar thermal power system (1982)
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    Publication Date: 2011-08-18
    Description: The development and preliminary test results for an air-cooled, hermetically sealed 20 kW sub E organic Rankine cycle engine/alternator unit for use with point focussing distributed receiver solar thermal power system. A 750 F toluene is the working fluid and the system features a high speed, single-stage axial flow turbine direct-coupled to a permanent magnet alternator. Good performance was achieved with the unit in preliminary tests.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 101-113
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  • 29
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    A transmittance-optimized, point-focus Fresnel lens solar concentrator (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The development of a point-focus Fresnel lens solar concentrator for high-temperature solar thermal energy system applications is discussed. The concentrator utilizes a transmittance-optimized, short-focal-length, dome-shaped refractive Fresnel lens as the optical element. This concentrator combines both good optical performance and a large tolerance for manufacturing, deflection, and tracking errors. The conceptual design of an 11-meter diameter concentrator which should provide an overall collector efficiency of about 70% at an 815 C (1500 F) receiver operating temperature and a 1500X geometric concentration ratio (lens aperture area/receiver aperture area) was completed. Results of optical and thermal analyses of the collector, a discussion of manufacturing methods for making the large lens, and an update on the current status and future plans of the development program are included.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 35-47
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  • 30
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    Lightning protection of wind turbines (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Possible damages to wind turbine components due to lightning strikes are discussed and means to prevent the damage are presented. A low resistance path to the ground is noted to be essential for any turbine system, including metal paths on nonmetal blades to conduct the strike. Surge arrestors are necessary to protect against overvoltages both from utility lines in normal operation and against lightning damage to control equipment and contactors in the generator. MOS structures are susceptible to static discharge injury, as are other semiconductor devices, and must be protected by the presence of static protection circuitry. It is recommended that the electronics be analyzed for the circuit transient response to a lightning waveform, to induced and dc current injection, that input/output leads be shielded, everything be grounded, and lightning-resistant components be chosen early in the design phase.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Effect of thickness on silicon solar cell efficiency (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A computer-aided-design study on the dependence of the efficiency peak of a back-surface field solar cell on the concentrations of the recombination and dopant impurities is presented. The illuminated current-voltage characteristics of more than 100 cell designs are obtained using the transmission line circuit model to numerically solve the Shockley equations. Using an AM 1 efficiency of 17% as a target value, it is shown that the efficiency versus thickness dependence has a broad maximum which varies by less than 1% over more than a three-to-one range of cell thicknesses from 30 to 100 microns. An optically reflecting back surface will give only a slight improvement of AM 1 efficiency, about 0.7%, in this thickness range. Attention is given to the dependence of the efficiency on patchiness across the back-surface field low-high junction in thin cells.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-29; May 1982
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  • 32
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    Interaction between cast silicon properties and solar cell performance (1982)
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    Publication Date: 2011-08-18
    Description: Three types of cast silicon, Silso, HEM (Heat-Exchanger Method) and UCP (Ubiquitous Crystallization Process) were studied for their use as solar cells. Optical microscopy after etching revealed a high density of uniform dislocations (approaching 1,000,000/sq cm), lines of dislocations indicating stress during crystal growth, and precipitates, some of which generate dislocations. Solar cells were fabricated by three processes. Results of solar cell processing revealed that these materials produce cells of lower efficiency than Czochralski control cells, and that the efficiencies of the three materials were quite close. Diffusion length and spectral response data are shown. Certain structural features are correlated with solar cell efficiency, diffusion length, and spectral response. Electron-beam induced current (EBIC) and light spot scanning are used to back up other measurements.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 33
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    Configuration selection study for isolated loads using parabolic dish modules (1982)
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    Publication Date: 2011-08-18
    Description: A configuration tradeoff study was conducted to determine optimum solar thermal parabolic dish power systems for isolated load applications. The specific application of an essentially constant power demand as required for MX missile shelters is treated. Supplying a continuous level of power with high reliability is shown to require a power system comprising modular parabolic dish power units where the heat engines of the modular power units can be driven by fossil fuels as well as solar-derived heat. Since constraints on reliability result in the provision of a power generating capability that exceeds the constant demand level, efficient utilization of the power system requires battery storage. Tradeoffs regarding the optimum size of storage are investigated as a function of the number of power modules and the cost of the fossil fuel.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 319-328
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  • 34
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    Ceramic high temperature receiver design and tests (1982)
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    Publication Date: 2011-08-18
    Description: The High Temperature Solar Thermal Receiver, which was tested a Edwards AFB, CA during the winter of 1980-1981, evolved from technologies developed over a five year period of work. This receiver was tested at the Army Solar Furnace at White Sands, NM in 1976. The receiver, was tested successfully at 1768 deg F and showed thermal efficiencies of 85%. The results were sufficiently promising to lead ERDA to fund our development and test of a 250 kW receiver to measure the efficiency of an open cavity receiver atop a central tower of a heliostat field. This receiver was required to be design scalable to 10, 50, and 100 MW-electric sizes to show applicability to central power tower receivers. That receiver employed rectagular silicon carbide panels and vertical stanchions to achieve scalability. The construction was shown to be fully scalable; and the receiver was operated at temperatures up to 2000 deg F to achieve the performance goals of the experiment during tests at the GIT advanced components test facility during the fall of 1978.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc. 247-255 (SEE N83-10525 01-44)
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  • 35
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    The French thermo-helio-electricity-KW parabolic dish program (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The testing and development of parabolic dish solar thermal power plants to produce, thermal mechanical, or electrical energy are discussed. The design, construction, and experiments of prototype collectors to prove the feasibility of such collectors is described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 225-231
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  • 36
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    Development status of the small community solar power system (1982)
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    Publication Date: 2011-08-18
    Description: The development status and test results for the Small Community Solar Thermal Power Experiment are presented. Activities on the phase 2 power module development effort are presented with emphasis on the receiver, the plant control subsystem, and the energy transport subsystem. The components include a single prototype power module consisting of a parabolic dish concentrator, a power conversion assembly (PCA), and a multiple-module plant control subsystem. The PCA consists of a cavity receiver coupled to an organic Rankine cycle engine-alternator unit defined as the power conversion subsystem; the PCA is mounted at the focus of a parabolic dish concentrator. At a solar insolation of 100 W/sq m and ambient temperature of 28 C (82 F), the power module produces approximately 20 kW of 3-phase, 3 kHz ac power, depending on the concentrator employed. A ground-mounted rectifier to the central collection site where it is supplied directly to the common dc bus which collects the power from all modules in the plant.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 53-99
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  • 37
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    Acurex Parabolic Dish Concentrator (PDC-2) (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The design approach, rationale for the selected configuration, and the development status of a cost effective point-focus solar concentrator are discussed. The low-cost concentrator reflective surface design is based on the use of a thin, backsilvered mirror glass reflector bonded to a molded structural plastic substrate. The foundation, support, and drive subassembles are described. A hybrid, two-axis, Sun tracking control system based on microprocessor technology was selected. Coarse synthetic tracking is achieved through a microcomputer-based control system to calculate Sun position for transient periods of cloud cover as well as sundown and sunrise positioning. Accurate active tracking is achieved by two-axis optical sensors. Results of the reflective panel demonstration tests investigating slope error, hail impact survivability, temperature/humidity cycling, longitudinal strength/bending stiffness, and torsional stiffness are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 15-20
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  • 38
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    Development status of the PDC-1 Parabolic Dish Concentrator (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The status of development of the 12 m diameter parabolic dish concentrator which is planned for use with the Small Community Solar Thermal Power System. The PDC-1 unit features the use of plastic reflector film bonded to structural plastic gores supported by front-bracing steel ribs. An elevation-over-azimuth mount arrangement is employed, with a conventional wheel-and-track arrangement; outboard trunnions permit the dish to be stored in the face down position, with the added advantage of easy access to the power conversion assembly. The control system is comprised of a central computer (LSI 1123), a manual control panel, a concentrator control unit, two motor controllers, a Sun sensor, and two angular position resolvers. The system is designed for the simultaneous control of several concentrators. The optical testing of reflective panels is described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 3-13
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  • 39
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    Commercialization of parabolic dish systems (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The impact of recent federal tax and regulatory legislation on the commercialization of parabolic solar reflector technology is assessed. Specific areas in need of technical or economic improvement are noted.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 201-205
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  • 40
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    PKI solar thermal plant evaluation at Capitol Concrete Products, Topeka, Kansas (1982)
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    Publication Date: 2011-08-18
    Description: A system feasibility test to determine the technical and operational feasibility of using a solar collector to provide industrial process heat is discussed. The test is of a solar collector system in an industrial test bed plant at Capitol Concrete Products in Topeka, Kansas, with an experiment control at Sandia National Laboratories, Albuquerque. Plant evaluation will occur during a year-long period of industrial utilization. It will include performance testing, operability testing, and system failure analysis. Performance data will be recorded by a data acquisition system. User, community, and environmental inputs will be recorded in logs, journals, and files. Plant installation, start-up, and evaluation, are anticipated for late November, 1981.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 119-121
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  • 41
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    The small community solar thermal power experiment (1982)
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    Publication Date: 2011-08-18
    Description: the objectives and current status of the Small Community Solar Thermal Power Experiment are discussed. The adjustments in programs goals made in response to the changing emphasis in the area of solar energy in national policy are addressed. Planned fabrication and testing activities for the test bed concentrator, power conversion assembly, and control system are outlined.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 49-52
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  • 42
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    The PKI collector (1982)
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    Publication Date: 2011-08-18
    Description: The design and manufacturing of a solar thermal collector is discussed. The collector has three primary subsystems: concentrator, receiver/fluid loop, and controls. Identical curved reflective columns are utilized in a faceted Fresnel design to support 864 one foot square flat inexpensive second-surface, silvered glass mirrors. The columns are ganged together and rotated through their centers of gravity to provide elevation tracking. The concentrator is supported by a lightweight spaceframe structure which distributes all wind and gravity loads to the base supports. The base of the structure is a track which rotates on wheels mounted on concrete piers. A parallel tube steel heat exchanger is mounted at the concentrator focal area in a well insulated, galvanized steel housing. Two rows of vertical close-packed, staggered tubes connect a mud header and a steam header. Automatic two axis tracking and operational control is provided with a microprocessor based package. Concentrator-mounted shadowbands are the basis for active tracking. A software program provides azimuthal tracking during cloudy periods.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 25-34
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  • 43
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    Garrett solar Brayton engine/generator status (1982)
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    Publication Date: 2011-08-18
    Description: The solar advanced gas turbine (SAGT-1) is being developed by the Garrett Turbine Engine Company, for use in a Brayton cycle power conversion module. The engine is derived from the advanced gas turbine (AGT101) now being developd by Garrett and Ford Motor Company for automotive use. The SAGT Program is presently funded for the design, fabrication and test of one engine at Garrett's Phoenix facility. The engine when mated with a solar receiver is called a power conversion module (PCU). The PCU is scheduled to be tested on JPL's test bed concentrator under a follow on phase of the program. Approximately 20 kw of electrical power will be generated.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 257-282
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  • 44
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    A point focusing collector for an integrated water/power complex (1982)
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    Publication Date: 2011-08-18
    Description: The utilization potential of the point focusing parabolic dish is identified. Its main design parameters are summarized. Performance tests and the utilization of the collector as primary energy source in a food-water-power complex are described. Process heat, heat storage, heat transfer, and cogeneration are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 207-223
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  • 45
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    A discrete gust model for use in the design of wind energy conversion systems (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A discrete gust model has been designed which includes an expression for the number of times per unit time thy wind exceeds a specific value. This expression, based on Rice's (1944, 1945) number-of-crossings model, assumes that the yearly mean wind speed is averaged over a period of 10 minutes to 1 (one) hour. Vertical and lateral coherence functions are the basis for a mathematical filter which isolates atmospheric disturbances of a characteristic size (e. g., those which would completely engulf a rotor). Predictions are calculated usising the given definition of cut-off frequency, then they are compared with actual data, showing that the model is reliable. The expression is provided in a format such that it may be used for engineering design calculations.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Applied Meteorology; 21; June 198
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  • 46
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    Solar/hydrogen systems for the 1985-2000 time frame - A review and assessment (1982)
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    Publication Date: 2011-08-18
    Description: A comprehensive state-of-the-art review of solar/hydrogen technologies has been conducted. From this, solar/hydrogen production systems which could be commercialized by the year 2000 have been characterized technically and economically. Incentives and disincentives for the early commercialization of four solar/hydrogen systems have been explored, conclusions drawn and recommendations made.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: International Journal of Hydrogen Energy; 7; 1, 19; 1982
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  • 47
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    Planar multijunction high voltage solar cell chip (1982)
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    Publication Date: 2011-08-18
    Description: A new innovative planar multijunction solar cell chip for concentrated sunlight applications is proposed. The chip consists of many voltage-generating regions, called unit cells, which are connected in series within a single silicon wafer, thereby providing a high open-circuit voltage at multiple sun illumination levels. The unit cells are fabricated on 75 micron thick p-type single crystal silicon substrate. Each chip consists of 1.42 x 9.63 mm n(+)/p collecting junctions on the back of the wafer, while the illuminated front surface area is divided into 0.3 micron deep n(+) regions. The fabrication sequence includes standard degreasing and cleaning procedures, double-sided alignment photomasking, introduction of boron and phosphorus impurities, and photolithography. The open circuit voltage of the chip increased rapidly with illumination up to about 4 AM1 suns, and then began to saturate at the sum of the individual unit cell voltages of 3.5 above 4 AM1 suns. A short circuit density per unit cell of 300 mA/sq cm at 20 AM1 suns was observed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Applied Physics; 53; Nov. 198
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  • 48
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    A review of resonance response in large, horizontal-axis wind turbines (1982)
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-23711)
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 29; 5, 19; 1982
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  • 49
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    Calibration of solar cells by the reference cell method - The spectral mismatch problem (1982)
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    Publication Date: 2011-08-18
    Description: The calibration of solar cells by means of solar simulators and calibrated reference cells has always been faced with the problem of errors due to source spectral irradiance mismatch and cell spectral response mismatch. A general expression is derived in this paper to enable calculation of mismatch error. The information required to make this calculation is the relative spectra responses of the test and reference cells, and the relative spectral irradiance of the simulator (over the spectral range defined by cell response). The spectral irradiance of the solar standard is assumed given. Experimental results are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 29; 4, 19; 1982
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  • 50
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    Hybrid thermoelectric solar collector design and analysis (1982)
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    Publication Date: 2011-08-18
    Description: A flat-plate solar collector is conceived where energy cascades through thermoelectric power modules generating direct-current electricity. The intent of this work was to choose a collector configuration and to perform a steady-state thermal performance assessment. A set of energy balance equations were written and solved numerically for the purpose of optimizing collector thermal and electrical performance. The collector design involves finned columns of thermoelectric modules imbedded in the absorber plate (hot junction) over a parallel array of vertical tubes. The thermoelectric power output is limited by the small hot-junction/cold-junction temperature difference which can be maintained under steady-state conditions. The electric power per unit tube pass area is found to have a maximum as a function of a geometric parameter, while electric power is maximized with respect to an electric resistance ratio. Although the electric power efficiency is small, results indicate that there is sufficient electric power production to drive a coolant circulator, suggesting the potential for a stand-alone system.
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  • 51
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    Energy consumption analysis for the Mars deep space station (1982)
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    Publication Date: 2011-08-18
    Description: Results for the energy consumption analysis at the Mars deep space station are presented. It is shown that the major energy consumers are the 64-Meter antenna building and the operations support building. Verification of the antenna's energy consumption is highly dependent on an accurate knowlege of the tracking operations. The importance of a regular maintenance schedule for the watt hour meters installed at the station is indicated.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Telecommun. and Data Acquisition Rept.; p 200-207
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  • 52
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    Analysis of capacitive heat exchangers, part 2 (1982)
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    Publication Date: 2011-08-18
    Description: The performance of a simple capacitive heat exchanger was analyzed. The shooting method for solving the governing equations is presented. Simplified linear and nonlinear models are analyzed using this method and it is shown that capacitive heat exchangers are more efficient than conventional ones.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Telecommun. and Data Acquisition Rept.; p 126-144
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  • 53
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    A simplified solar cell array modelling program (1982)
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    Publication Date: 2011-08-18
    Description: As part of the energy conversion/self sufficiency efforts of DSN engineering, it was necessary to have a simplified computer model of a solar photovoltaic (PV) system. This article describes the analysis and simplifications employed in the development of a PV cell array computer model. The analysis of the incident solar radiation, steady state cell temperature and the current-voltage characteristics of a cell array are discussed. A sample cell array was modelled and the results are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Telecommun. and Data Acquisition Rept.; p 167-185
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  • 54
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    Experience with specifications applicable to certification (1982)
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    Publication Date: 2011-08-18
    Description: The Jet Propulsion Laboratory has developed a number of photovoltaic test and measurement specifications to guide the development of modules toward the requirements of future large-scale applications. Experience with these specifications and the extensive module measurement and testing that has accompanied their use is examined. Conclusions are drawn relative to three aspects of product certification: performance measurement, endurance testing and safety evaluation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 55
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    Layered transition metal thiophosphates /MPX3/ as photoelectrodes in photoelectrochemical cells (1982)
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    Publication Date: 2011-08-18
    Description: Layered crystals of the transition metal thiophosphates were synthesized and characterized for use as photoelectrodes in photoelectrochemical cells. Crystals incorporating tin and manganese show n-type response while those with iron and nickel show p-type response. These materials have a measured indirect bandgap of about 2.1 eV. They show ability to photoelectrolyze water in acid solutions with onset potentials which change in a Nernstian way as the PH of the solution changes. The onset potential is near zero volts versus a saturated calomel electrode at pH 2. At n-type crystals, oxygen could be evolved upon irradiation at underpotentials of 850 mV and at p-type crystals, hydrogen could be evolved at underpotentials of 400 mV, indicating a net gain in energy conversion. All crystals were unstable in basic solution. Liquid junction photovoltaic cells in iodide-triiodide acid solution using these layered materials were also constructed and found to have low efficiences.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy Materials; 7; Sept
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    Panel discussions: Industrial support sector requirements (1982)
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    Publication Date: 2011-08-18
    Description: Industrial support was the subject of a panel discussion on solar energy technology. Members of various energy-related businesses and agencies were present. Topics cofered include: (1) solar collectors; (2) solar energy policy; (3) government/industry relations; and (4) economic factors which influence the use of solar energy.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 339-353
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  • 57
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    Application of the subatmospheric engine to solar thermal power (1982)
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    Publication Date: 2011-08-18
    Description: The development of a natural gas-fired Brayton engine is discussed. It is intended to be the prime mover for a 10-ton commercial heat pump. This engine has many attractive features that make it an ideal candidate for solar thermal-power generation applications. The unique feature of this engine is its subatmospheric mode of operation. It operates between atmospheric pressure and a partial vacuum. This means that heat is added to the cycle at atmospheric pressure; this permits the receiver to be unpressurized, greatly simplifying its design and cost.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 283-293
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  • 58
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    Thin film concentrator panel development (1982)
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    Publication Date: 2011-08-18
    Description: The development and testing of a rigid panel concept that utilizes a thin film reflective surface for application to a low-cost point-focusing solar concentrator is discussed. It is shown that a thin film reflective surface is acceptable for use on solar concentrators, including 1500 F applications. Additionally, it is shown that a formed steel sheet substrate is a good choice for concentrator panels. The panel has good optical properties, acceptable forming tolerances, environmentally resistant substrate and stiffeners, and adaptability to low to mass production rates. Computer simulations of the concentrator optics were run using the selected reflector panel design. Experimentally determined values for reflector surface specularity and reflectivity along with dimensional data were used in the analysis. The simulations provided intercept factor and net energy into the aperture as a function of aperture size for different surface errors and pointing errors. Point source and Sun source optical tests were also performed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 25-34
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  • 59
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    A 400-kWe high-efficiency steam turbine for industrial cogeneration (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An advanced state-of-the-art steam turbine-generator developed to serve as the power conversion subsystem for the Department of Energy's Sandia National Laboratories' Solar Total-Energy Project (STEP) is described. The turbine-generator, which is designed to provide 400-kW of net electrical power, represents the largest turbine-generator built specifically for commercial solar-powered cogeneration. The controls for the turbine-generator incorporate a multiple, partial-arc entry to provide efficient off-design performance, as well as an extraction control scheme to permit extraction flow regulation while maintaining 110-spsig pressure. Normal turbine operation is achieved while synchronized to a local utility and in a stand-alone mode. In both cases, the turbine-generator features automatic load control as well as remote start-up and shutdown capability. Tests totaling 200 hours were conducted to confirm the integrity of the turbine's mechanical structure and control function. Performance tests resulted in a measured inlet throttle flow of 8,450 pounds per hour, which was near design conditions.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Parabolic Dish Solar Thermal Power Ann. Program Rev., Proc.; p 147-177
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    Thickness dependences of solar cell performance (1982)
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    Publication Date: 2011-08-18
    Description: The significance of including factors such as the base resistivity loss for solar cells thicker than 100 microns and emitter and BSF layer recombination for thin cells in predicting the fill factor and efficiency of solar cells is demonstrated analytically. A model for a solar cell is devised with the inclusion of the dopant impurity concentration profile, variation of the electron and hole mobility with dopant concentration, the concentration and thermal capture and emission rates of the recombination center, device temperature, the AM1 spectra and the Si absorption coefficient. Device equations were solved by means of the transmission line technique. The analytical results were compared with those of low-level theory for cell performance. Significant differences in predictions of the fill factor resulted, and inaccuracies in the low-level approximations are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solid-State Electronics; 25; Sept
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    Reduction of solar cell efficiency by edge defects across the back-surface-field junction - A developed perimeter model (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Material imperfections, impurity clusters and fabrication defects across the back-surface-field junction can degrade the performance of high-efficiency solar cells. The degradation from defects appearing on the circumference of a solar cell is analyzed using a two-region developed perimeter device model. The width of the defective perimeter region is characterized by the range or the distance-of-influence of the defective edge and this width is about two diffusion lengths. The defective edge is characterized by a surface recombination velocity. Family of theoretical curves and numerical examples are presented to show that significant reduction of open-circuit voltage can occur in high-efficiency cells which are thin compared with the diffusion length. In one example, the degradation is decreased from 135 mV to 75 mV when the cell size is increased from 10 to 100 times the diffusion length in a thin cell whose thickness is 1% of the diffusion length.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solid-State Electronics; 25; Sept
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    A technique for determining solar irradiance deficits (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An analytic technique which determines the variation of solar irradiance from long term averages is presented. The technique involves computer-assisted data reduction techniques, and was designed to improve system reliability by determining the amount of storage capability required to supplement a baseline system. Variations in time intervals of up to 60 days can be determined, and 10 years of data collection are reviewed. The technique involves first calculating average monthly irradiance values, then examining the average irradiance deviation over time intervals. The calculation procedure is clarified by determining solar energy level probabilities and the long term solar energy deviation (achieved by repeatedly integrating actual irradiance figures). It is found that a 15% increase in collector area and the addition of energy storage or backup are essential contributions to achieving cost-effectiveness. In addition, one to seven no-sun day storage capacities are required to accommodate weather caused deficits.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Reliability; R-31; Aug. 198
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    Investigating reliability attributes of silicon photovoltaic cells - An overview (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Reliability attributes are being developed on a wide variety of advanced single-crystal silicon solar cells. Two separate investigations: cell-contact integrity (metal-to-silicon adherence), and cracked cells identified with fracture-strength-reducing flaws are discussed. In the cell-contact-integrity investigation, analysis of contact pull-strength data shows that cell types made with different metallization technologies, i.e., vacuum, plated, screen-printed and soldered, have appreciably different reliability attributes. In the second investigation, fracture strength was measured using Czochralski wafers and cells taken at various stages of processing and differences were noted. Fracture strength, which is believed to be governed by flaws introduced during wafer sawing, was observed to improve (increase) after chemical polishing and other process steps that tend to remove surface and edge flaws.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Reliability; R-31; Aug. 198
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  • 64
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    Qualification testing of flat-plate photovoltaic modules (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The placement of photovoltaic modules in various applications, in climates and locations throughout the world, results in different degrees and combinations of environmental and electrical stress. Early detection of module reliability deficiencies via laboratory testing is necessary for achieving long, satisfactory field service. This overview paper describes qualification testing techniques being used in the US Department of Energy's flat-plate terrestrial photovoltaic development program in terms of their significance, rationale for specified levels and durations, and test results.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Reliability; R-31; Aug. 198
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    Accelerated stress testing of terrestrial solar cells (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The development of an accelerated test schedule for terrestrial solar cells is described. This schedule, based on anticipated failure modes deduced from a consideration of IC failure mechanisms, involves bias-temperature testing, humidity testing (including both 85-85 and pressure cooker stress), and thermal-cycle thermal-shock testing. Results are described for 12 different unencapsulated cell types. Both gradual electrical degradation and sudden catastrophic mechanical change were observed. These effects can be used to discriminate between cell types and technologies relative to their reliability attributes. Consideration is given to identifying laboratory failure modes which might lead to severe degradation in the field through second quadrant operation. Test results indicate that the ability of most cell types to withstand accelerated stress testing depends more on the manufacturer's design, processing, and worksmanship than on the particular metallization system. Preliminary tests comparing accelerated test results on encapsulated and unencapsulated cells are described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Reliability; R-31; Aug. 198
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    Photovoltaic array reliability optimization (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An overview of the photovoltaic array reliability problem is presented, and a high reliability/minimum cost approach to this problem is presented. Design areas covered are cell failure, interconnect fatigue, and electrical insulation breakdown, and three solution strategies are discussed. The first involves controlling component failures in the solar cell (cell cracking, cell interconnects) and at the module level (must be statistically treated). Second, a fault tolerant circuit is designed which reduces array degradation, improves module yield losses, and controls hot-spot heating. Third, cost optimum module replacement strategies are also effective in reducing array degradation. This can be achieved by minimizing the life-cycle energy cost of the photovoltaic system. The integration of these solutions is aimed at reducing the 0.01% failure rate.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Reliability; R-31; Aug. 198
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    Photovoltaic module reliability improvement through application testing and failure analysis (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: During the first four years of the U.S. Department of Energy (DOE) National Photovoltatic Program, the Jet Propulsion Laboratory Low-Cost Solar Array (LSA) Project purchased about 400 kW of photovoltaic modules for test and experiments. In order to identify, report, and analyze test and operational problems with the Block Procurement modules, a problem/failure reporting and analysis system was implemented by the LSA Project with the main purpose of providing manufacturers with feedback from test and field experience needed for the improvement of product performance and reliability. A description of the more significant types of failures is presented, taking into account interconnects, cracked cells, dielectric breakdown, delamination, and corrosion. Current design practices and reliability evaluations are also discussed. The conducted evaluation indicates that current module designs incorporate damage-resistant and fault-tolerant features which address field failure mechanisms observed to date.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Reliability; R-31; Aug. 198
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  • 68
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    Reduction of solar cell efficiency by bulk defects across the back-surface-field junction (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The degradation of solar cell performance due to bulk defects distributed across the back-surface field junction is analyzed in terms of a three-region developed-perimeter model. Families of curves are computed and their physical significance is discussed in detail with reference to three parameters used to characterize the defects: defect area, defect density, and defect surface recombination velocity. A reduction in the open-circuit voltage due to the presence of a defect is expressed as a function of the defect area, density, cell thickness, and defect surface recombination velocity. Numerical examples are presented to illustrate the importance of the particular defect parameters.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Applied Physics; 53; Apr. 198
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  • 69
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    Minimum silicon wafer thickness for ID wafering (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An analytical model, based on fracture mechanics analysis, is proposed for estimating the minimum wafer thickness as a function of the diameter requirement for solar cells. The conditions under which the model can be applied are discussed with reference to the critical flaw size, the applied force, and the width of the side support. It is shown that the equivalent cantilever force applied during ID slicing can be estimated from the wafering mechanical yield data. The width of the wafer side support was found to be a significant factor in controlling the minimum allowable wafer thickness during slicing. Wafer side support width requirements were found to increase with decreasing wafer thickness.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Electrochemical Society; vol. 129
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    Cost estimates for flat plate and concentrator collector arrays (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The current module and installation costs for the U.S. National Photovoltaic Program's grid-connected systems are significantly higher than required for economic viability of this alternative. Attention is accordingly given to the prospects for installed module cost reductions in flat plate, linear focus Fresnel concentrator, and point focus Fresnel concentrator candidate systems. Cost projections indicate that all three systems would meet near-term and midterm goals, provided that module costs of $2.80/W(p) and $0.70/W(p), respectively, are met. The point focus Fresnel system emerges as the most viable for the near term.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Japanese Journal of Applied Physics (ISSN 0021-4922); 21; 143-153
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  • 71
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    The worldwide market for photovoltaics in the rural sector (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Attention is given to the assessment of results obtained by three NASA studies aimed at determining the global market for stand-alone photovoltaic (PV) power systems in the village power, cottage industry, and agricultural applications areas of the rural sector. An attempt was made to identify technical, social, and institutional barriers to PV system implementation, as well as the funding sources available to potential users. Country- and sector-specific results are discussed, and marketing strategies appropriate for each sector are suggested for the benefit of American PV products manufacturers.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Empirical testing of structural deflection modeling of large photovoltaic modules (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The objective of the structural deflection test was to verify the analytical models used to predict solar cell stress, load-bearing layer stress, and module deflection that result from a uniform pressure load on the module surface. The verification process consisted of measuring module deflection, stress in the solar cell, and stress in the load-bearing member as a functon of normal pressure load, pottant modulus of elasticity, pottant thickness, and cell location. Four glass superstrate modules, two plain wood substrate modules, two ribbed wood substrate modules, and a steel substrate module were tested. Consistent with analysis predictions, all unribbed specimens exhibited nonlinear load vs. deflection characteristics. With the exception of the steel module, test results and analysis predictions for panel deflectons agreed to within 10 percent. A wider variation of agreement was found for stress in the load-bearing members and cells.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 73
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    Empirical testing of an analytical model predicting electrical isolation of photovoltaic models (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: 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.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Effects of indirect bandgap top cells in a monolithic cascade cell structure (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The effect of having a slightly indirect top cell in a three junction cascade monolithic stack is calculated. The minority carrier continuity equations are utilized to calculate individual junction performance. Absorption coefficient curves for general III-V compounds are calculated for a variety of direct and indirect gap materials. The results indicate that for a small excursion into the indirect region, (about 0.1 eV), the loss of efficiency is acceptably small (less than 2.5 percent) and considerably less than attempting to make the top junction a smaller direct bandgap.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Flat-plate solar array progress and plans (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The emphasis of the Flat-plate Solar Array Project has been shifted from price goals and commercial development toward longer-term, higher risk, higher-potential-payoff opportunities. The revised objectives, status, and plans of the project are presented and technical progress is noted in the areas of: large-area sheet formation; silicon feedstock refinement; flat-plate module process sequence development; and engineering and environmental testing.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Status of AlGaAs/GaAs heteroface solar cell technology (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper reviews the various GaAs solar cell programs that have been and are now ongoing which are directed at bringing this particular technology to fruition. The discussion emphasizes space application - both concentrator and flat plate. The rationale for pursuing GaAs cell technology is given along with the different cell types (concentrator, flat plate), approaches to fabricate the devices, the hybrid cells under investigation and approaches to reduce cell mass are summarized. The outlook for the use of GaAs cell technology is given within the context for space application.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Parallel-processing with surface plasmons, a new strategy for converting the broad solar spectrum (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new strategy for efficient solar-energy conversion is based on parallel processing with surface plasmons: guided electromagnetic waves supported on thin films of common metals like aluminum or silver. The approach is unique in identifying a broadband carrier with suitable range for energy transport and an inelastic tunneling process which can be used to extract more energy from the more energetic carriers without requiring different materials for each frequency band. The aim is to overcome the fundamental 56-percent loss associated with mismatch between the broad solar spectrum and the monoenergetic conduction electrons used to transport energy in conventional silicon solar cells. This paper presents a qualitative discussion of the unknowns and barrier problems, including ideas for coupling surface plasmons into the tunnels, a step which has been the weak link in the efficiency chain.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 78
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    An accelerated stress testing program for determining the reliability sensitivity of silicon solar cells to encapsulation and metallization systems (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The use of accelerated testing methods in a program to determine the reliability attributes of terrestrial silicon solar cells is discussed. Different failure modes are to be expected when cells with and without encapsulation are subjected to accelerated testing and separate test schedules for each are described. Unencapsulated test cells having slight variations in metallization are used to illustrate how accelerated testing can highlight different diffusion related failure mechanisms. The usefulness of accelerated testing when applied to encapsulated cells is illustrated by results showing that moisture related degradation may be many times worse with some forms of encapsulation than with no encapsulation at all.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 79
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    Investigation of energy management strategies for photovoltaic systems - An analysis technique (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Progress is reported in formulating energy management strategies for stand-alone PV systems, developing an analytical tool that can be used to investigate these strategies, applying this tool to determine the proper control algorithms and control variables (controller inputs and outputs) for a range of applications, and quantifying the relative performance and economics when compared to systems that do not apply energy management. The analysis technique developed may be broadly applied to a variety of systems to determine the most appropriate energy management strategies, control variables and algorithms. The only inputs required are statistical distributions for stochastic energy inputs and outputs of the system and the system's device characteristics (efficiency and ratings). Although the formulation was originally driven by stand-alone PV system needs, the techniques are also applicable to hybrid and grid connected systems.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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    Solubility of Sulfur Dioxide in Sulfuric Acid (1982)
    In:  CASI
    Details
    Publication Date: 2016-05-11
    Description: The solubility of sulfur dioxide in 50% (wt./wt.) sulfuric acid was evaluated by regular solution theory, and the results verified by experimental measurements in the temperature range of 25 C to 70 C at pressures of 60 to 200 PSIA. The percent (wt./wt.) of sulfur dioxide in 50% (wt./wt.) sulfuric acid is given by the equation %SO2 = 2.2350 + 0.0903P - 0.00026P 10 to the 2nd power with P in PSIA.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: MCC Associates, Inc. Proc. of the 6th Ann. Thermal and Chem. Storage Contractors' Rev. Meeting; p 52-56
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    Block 5 module design summary (1982)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: The Flat Plate Solar Array Block 5 Module design efforts of six manufacturers are summarized. Residential designs and module designs for intermediate-load applications are described. It is planned that a few prototype modules of each design will be fabricated. The modules incorporate advanced concepts, are larger than earlier ones and have high power output.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Flat Plate Solar Array Proj.: Proc. of the 20th Proj. Integration Meeting; p 99-103
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    Radiation-driven MHD systems for space applications (1982)
    In:  Other Sources
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    Publication Date: 2019-01-25
    Description: High-power radiation such as concentrated solar or high-power laser radiation is considered as a driver for magnetohydrodynamic (MHD) systems which could be developed for efficient power generation and propulsion in space. Eight different systems are conceivable since the MHD systems can be classified in two: plasma and liquid-metal MHD's. Each of these systems is reviewed and solar- (or laser-) driven MHD thrusters are proposed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: R and D Associates Proc. of the AFOSR Spec. Conf. on Prime-Power for High Energy Space Systems, Vol. 2; 11 p
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    Status of thermoelectronic laser energy conversion, TELEC (1982)
    In:  Other Sources
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    Publication Date: 2019-01-25
    Description: A concept known as a thermo-electronic laser energy converter (TELEC), was studied as a method of converting a 10.6 micron CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma were produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: R and D Associates Proc. of the AFOSR Spec. Conf. on Prime-Power for High Energy Space Systems, Vol. 2; 11 p
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    Wafering insight provided by the ODE method (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The orientation-dependent etching method of slicing was investigated to see if it could be used to form more slices from high quality silicon crystals than can be achieved by mechanical slicing methods. Orientation-dependent slicing uses preferential etching down narrow slots in a silicon slab on form slices. The method has several possible advantages including high slicing yield (sq m/kg), plane parallel, thin slices, ready for processing and the chance of high throughput and low costs. There are limitations in the need for simple crystals, and in restricted depth of slicing.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Low-Cost Solar Array Wafering Workshop; p 259-266
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    Diamond Sheet: A new diamond tool material (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Diamond sheet is termed a diamond tool material because it is not a cutting tool, but rather a new material from which a variety of different tools may be fabricated. In appearance and properties, it resembles a sheet of copper alloy with diamond abrasive dispersed throughout it. It is capable of being cut, formed, and joined by conventional methods, and subsequently used for cutting as a metal bonded diamond tool. Diamond sheet is normally made with industrial diamond as the abrasive material. The metal matrix in diamond sheet is a medium hard copper alloy which has performed well in most applications. This alloy has the capability of being made harder or softer if specific cutting conditions require it. Other alloys have also been used including a precipitation hardened aluminum alloy with very free cutting characteristics. The material is suitable for use in a variety of cutting, surfacing, and ring type tools, as well as in such mundane items as files and sandpaper. It can also be used as a bearing surface (diamond to diamond) and in wear resistant surfaces.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Low-Cost Solar Array Wafering Workshop; p 249-252
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  • 86
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    Overview of a new slicing method: Fixed Abrasive Slicing Technique (FAST) (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The fixed abrasive slicing technique (FAST) was developed to slice silicon ingots more effectively. It was demonstrated that 25 wafers/cm can be sliced from 10 cm diameter and 19 wafers/cm from 15 cm diameter ingots. This was achieved with a combination of machine development and wire-blade development programs. Correlation was established between cutting effectiveness and high surface speeds. A high speed slicer was designed and fabricated for FAST slicing. Wirepack life of slicing three 10 cm diameter ingots was established. Electroforming techniques were developed to control widths and prolong life of wire-blades. Economic analysis indicates that the projected add-on price of FAST slicing is compatible with the DOE price allocation to meet the 1986 cost goals.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Low-Cost Solar Array Wafering Workshop; p 233-241
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  • 87
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    ID wafering technology (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Improvements in ID saws leading to lower costs for producing silicon wafers for solar cells are described. The relationships between crystal size and blade size and between the length of time it takes to slice a wafer and wafer thickness are discussed. The influence of ingot production methods on wafering performance is considered. A cost sensitivity analysis of slicing a 10 cm square ingot and economic analyses of slicing a four inch and a six inch ingot are presented. A wafering cost model based on the IPEG 2 is given.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Low-Cost Solar Array Wafering Workshop; p 35-46
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    Kinematical and mechanical aspects of wafer slicing (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Some recently achieved results concerning the technological fundamentals of slurry sawing are presented. The specific material removal process and the related kinematic and geometric contact conditions between workpiece and saw blade are described. The result of a functional description of the slurry sawing process is presented, expressing the main process criteria, such as infeed per stroke, specific removal rate, specific tool wear, and vertical stroke intensity, in terms of the dominating process parameters, such as stroke length, width of workpiece, stroke frequency, specific cutting force and slurry specification.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Low-Cost Solar Array Wafering Workshop; p 141-157
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    Design and use of multiple blade slurry sawing in a production atmosphere (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The technique and uses of the multiple blade slurry (MBS) saw are considered. Multiple bands of steel are arranged in a frame and the frame is reciprocated with the steel bands to a workpiece, while simultaneously applying abrasive at the point of contact. The blades wear slots in the workpiece and progress through the piece resulting in several parts of wafers. The transition to MBA from diamond slicing is justified by savings resulting from minimized kerf losses, minimized subsurface damage, and improved surface quality off the saw. This allows wafering much closer to finished thickness specifications. The current state of the art MBS technology must be significantly improved if the low cost solar array (LSA) goals are to be attained. It is concluded that although MBS will never be the answer to every wafering requirement, the economical production of wafers to LSA project specifications will be achieved.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proc. of the Low-Cost Solar Array Wafering Workshop; p 133-139
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  • 90
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    Corrosion inhibitors for water-base slurry in multiblade sawing (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The use of a water-base slurry instead of the standard PC oil vehicle was proposed for multiblade sawing (MBS) silicon wafering technology. Potential cost savings were considerable; however, significant failures of high-carbon steel blades were observed in limited tests using a water-based slurry during silicon wafering. Failures were attributed to stress corrosion. A specially designed fatigue test of 1095 steel blades in distilled water with various corrosion inhibitor solutions was used to determine the feasibility of using corrosion inhibitors in water-base MBS wafering. Fatigue tests indicate that several corrosion inhibitors have significant potential for use in a water-base MBS operation. Blade samples tested in these specific corrosion-inhibitor solutions exhibited considerably greater lifetime than those blades tested in PC oil.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Low-Cost Solar Array Wafering Workshop; p 159-174
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    System for slicing wafers (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A newly patented process for slicing silicon wafers that has distinct advantages over methods now widely used is described. The primary advantage of the new system is that it allows the efficient slicing of a number of ingots simultaneously at high speed. The cutting action is performed mechanically, most often with diamond particles that are transported to the cutting zone by a fluid vehicle or have been made an integral part of the blade by plating or impregnation. The new system uses a multiple or ganged band saw, arranged and spaced so that each side, or length, segment of a blade element, or loop, provides a cutting function. Each blade is maintained precisely in position by guides as it enters and leaves each ingot. The cutting action is performed with a conventional abrasive slurry composed of diamond grit suspended in an oil- or water-based vehicle. The distribution system draws the slurry from the supply reservoir and pumps it to the injection tubes to supply it to each side of each ingot. A flush system is provided at the outer end of the work-station zone. In order to reduce potential damage, a pneumatically driven flushing fluid is provided.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Low-Cost Solar Array Wafering Workshop; p 243-248
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  • 92
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    Sensitivity analysis of add-on price estimate for select silicon wafering technologies (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The cost of producing wafers from silicon ingots is a major component of the add-on price of silicon sheet. Economic analyses of the add-on price estimates and their sensitivity internal-diameter (ID) sawing, multiblade slurry (MBS) sawing and fixed-abrasive slicing technique (FAST) are presented. Interim price estimation guidelines (IPEG) are used for estimating a process add-on price. Sensitivity analysis of price is performed with respect to cost parameters such as equipment, space, direct labor, materials (blade life) and utilities, and the production parameters such as slicing rate, slices per centimeter and process yield, using a computer program specifically developed to do sensitivity analysis with IPEG. The results aid in identifying the important cost parameters and assist in deciding the direction of technology development efforts.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Proc. of the Low-Cost Solar Array Wafering Workshop; p 197-209
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  • 93
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    Fiberglass Composite Blades for the 4 MW - WTS-4 Wind Turbine (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The design and fabrication of composite blades for the WTS-4, a four-megawatt horizontal-axis wind turbine, is discussed. The blade consists of a two-cell, monolithic structure of filament-wound, fiberglass/epoxy composite. Filament winding is a low-cost process which can produce a blade with an aerodynamically efficient airfoil and planform with nonlinear twist to achieve high performance in terms of energy capture. Its retention provides a redundant attachment for long, durable life and safety. Advanced tooling concepts and as sophisticated computer control is used to achieve the unique filament-wound shape.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Large Horizontal-Axis Wind Turbines; p 259-266
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  • 94
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    Low-cost composite blades for the Mod-0A wind turbines (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Low cost approaches to the design and fabrication of blades for a two-bladed 200 kW wind turbine were identified and the applicability of the techniques to larger and smaller blades was assessed. Blade tooling was designed and fabricated. Two complete blades and a partial blade for tool tryout were built. The patented TFT process was used to wind the entire blade. This process allows rapid winding of an axially oriented composite onto a tapered mandrel, with tapered wall thickness. The blade consists of a TFT glass-epoxy airfoil structure filament wound onto a steel root end fitting. The fitting is, in turn, bolted to a conical steel adapter section to provide for mounting attachment to the hub. Structural analysis, blade properties, and cost and weight analysis are described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Large Horizontal-Axis Wind Turbines; p 239-258
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  • 95
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    Conceptual design of the 7 megawatt Mod-5B wind turbine generator (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Similar to MOD-2, the MOD-5B wind turbine generator system is designed for the sole purpose of providing electrical power for distribution by a major utility network. The objectives of the MOD-2 and MOD-5B programs are essentially identical with one important exception; the cost-of-electricity (COE) target is reduced from 4 cent/Kwhr on MOD-2 to 3 cent/Kwhr on MOD-5B, based on mid 1977 dollars and large quantity production. The MOD-5B concept studies and eventual concept selection confirmed that the program COE targets could not only be achieved but substantially bettered. Starting from the established MOD-2 technology as a base, this achievement resulted from a combination of concept changes, size changes, and design refinements. The result of this effort is a wind turbine system that can compete with conventional power generation over significant geographical areas, increasing commercial market potential by an order of magnitude.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Large Horizontal-Axis Wind Turbines; p 821-833
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  • 96
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    Radiation damage (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The radiation damage workshop considered a variety of topics among which were the need for equivalent electron fluences in gallium arsenide, the possibility of 15 percent end-of-life efficiencies for silicon, increasing radiation resistance in gallium arsenide, annealing of radiation damage and the need for radiation damage studies in cascade cells. The workshop members agreed that a high priority should be assigned to obtaining equivalent electron fluences for gallium arsenide cells. It was suggested that 1 MeV would be a reasonable electron energy for this purpose. Special care should be given to proton irradiations particularly for energies below 1 MeV. In addition, omnidirectional rather than normal incidence protons should be used. It was also agreed that there was a need for obtaining damage coefficients in gallium arsenide. In silicon, there is a requirement for additional flight data, especially in proton dominated orbits. These data are needed to further check the accuracy of the 1 MeV equivalence fluences.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Res. and Technol. 1982: High Efficiency, Radiation Damage, and Blanket Technol.; p 267-268
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  • 97
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    Operational experience on the MP-200 series commercial wind turbine generators (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The MP-200 wind turbine generator is described. The mechanical system, microprocessor controller, and display devices, are described. Also discussed are modifications to the prototype, operational experience, and MP-600 systems development.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Large Horizontal-Axis Wind Turbines; p 593-605
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  • 98
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    Development tests for the 2.5 megawatt Mod-2 wind turbine generator (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The 2.5 megawatt MOD-2 wind turbine generator test program is discussed. The development of the 2.5 megawatt MOD-2 wind turbine generator included an extensive program of testing which encompassed verification of analytical procedures, component development, and integrated system verification. The test program was to assure achievement of the thirty year design operational life of the wind turbine system as well as to minimize costly design modifications which would otherwise have been required during on site system testing. Computer codes were modified, fatigue life of structure and dynamic components were verified, mechanical and electrical component and subsystems were functionally checked and modified where necessary to meet system specifications, and measured dynamic responses of coupled systems confirmed analytical predictions.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Large Horizontal-Axis Wind Turbines; p 611-633
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    Description of the 3 MW SWT-3 wind turbine at San Gorgonio Pass, California (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The SWT-3 wind turbine, a microprocessor controlled three bladed variable speed upwind machine with a 3MW rating that is presently operational and undergoing system testing, is discussed. The tower, a rigid triangular truss configuration, is rotated about its vertical axis to position the wind turbine into the prevailing wind. The blades rotate at variable speed in order to maintain an optimum 6 to 1 tip speed ratio between cut in and fated wind velocity, thereby maximizing power extraction from the wind. Rotor variable speed is implemented by the use of a hydrostatic transmission consisting of fourteen fixed displacement pumps operating in conjunction with eighteen variable displacement motors. Full blade pitch with on-off hydraulic actuation is used to maintain 3MW of output power.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Large Horizontal-Axis Wind Turbines; p 575-588
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  • 100
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    Experience and Assessment of the DOE/NASA Mod-1 2000 Kw Wind Turbine Generator at Boone, North Carolina (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Mod 1 program objectives are defined. The Mod 1 wind turbine is described. In addition to the steel blade operated on the wind turbine, a composite blade was designed and manufactured. During the early phase of the manufacturing cycle of Mod 1A configuration was designed that identified concepts such as partial span control, a soft tower, and upwind teetered rotors that were incorporated in second and third generation industry designs. The Mod 1 electrical system performed as designed, with voltage flicker characteristics within acceptable utility limits.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Large Horizontal-Axis Wind Turbines; p 491-571
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