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Sample records for photovoltaic array fact

  1. Photovoltaics (Fact Sheet)

    SciTech Connect

    Not Available

    2012-11-01

    The U.S. Department of Energy (DOE) works with industry, academia, national laboratories, and other government agencies to advance solar photovoltaics (PV) domestically. The SunShot Initiative aims to achieve widespread, unsubsidized cost-competitiveness through an applied research and development (R&D) portfolio spanning PV materials, devices, and manufacturing technologies.

  2. Photovoltaics (Fact Sheet)

    SciTech Connect

    Not Available

    2011-10-01

    DOE works with national labs, academia, and industry to support the domestic photovoltaics (PV) industry and research enterprise. SunShot aims to achieve widespread, unsubsidized cost-competitiveness through an applied research and development (R&D) portfolio spanning PV materials, devices, and manufacturing technologies.

  3. Photovoltaics (Fact Sheet)

    SciTech Connect

    DOE Solar Energy Technologies Program

    2011-10-13

    DOE works with national labs, academia, and industry to support the domestic photovoltaics (PV) industry and research enterprise. SunShot aims to achieve widespread, unsubsidized cost-competitiveness through an applied research and development (R&D) portfolio spanning PV materials, devices, and manufacturing technologies.

  4. Photovoltaic array performance model.

    SciTech Connect

    Kratochvil, Jay A.; Boyson, William Earl; King, David L.

    2004-08-01

    This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

  5. Photovoltaic cell array

    NASA Technical Reports Server (NTRS)

    Eliason, J. T. (Inventor)

    1976-01-01

    A photovoltaic cell array consisting of parallel columns of silicon filaments is described. Each fiber is doped to produce an inner region of one polarity type and an outer region of an opposite polarity type to thereby form a continuous radial semi conductor junction. Spaced rows of electrical contacts alternately connect to the inner and outer regions to provide a plurality of electrical outputs which may be combined in parallel or in series.

  6. Integrated residential photovoltaic array development

    NASA Astrophysics Data System (ADS)

    Shepard, N. F., Jr.

    1981-12-01

    An advanced, universally-mountable, integrated residential photovoltaic array concept was defined based upon an in-depth formulation and evaluation of three candidate approaches which were synthesized from existing or proposed residential array concepts. The impact of module circuitry and process sequence is considered and technology gaps and performance drivers associated with residential photovoltaic array concepts are identified. The actual learning experience gained from the comparison of the problem areas of the hexagonal shingle design with the rectangular module design led to what is considered an advanced array concept. Building the laboratory mockup provided actual experience and the opportunity to uncover additional technology gaps.

  7. Integrated residential photovoltaic array development

    NASA Technical Reports Server (NTRS)

    Shepard, N. F., Jr.

    1981-01-01

    An advanced, universally-mountable, integrated residential photovoltaic array concept was defined based upon an in-depth formulation and evaluation of three candidate approaches which were synthesized from existing or proposed residential array concepts. The impact of module circuitry and process sequence is considered and technology gaps and performance drivers associated with residential photovoltaic array concepts are identified. The actual learning experience gained from the comparison of the problem areas of the hexagonal shingle design with the rectangular module design led to what is considered an advanced array concept. Building the laboratory mockup provided actual experience and the opportunity to uncover additional technology gaps.

  8. Temperature compensated photovoltaic array

    DOEpatents

    Mosher, D.M.

    1997-11-18

    A temperature compensated photovoltaic module comprises a series of solar cells having a thermally activated switch connected in parallel with several of the cells. The photovoltaic module is adapted to charge conventional batteries having a temperature coefficient differing from the temperature coefficient of the module. The calibration temperatures of the switches are chosen whereby the colder the ambient temperature for the module, the more switches that are on and form a closed circuit to short the associated solar cells. By shorting some of the solar cells as the ambient temperature decreases, the battery being charged by the module is not excessively overcharged at lower temperatures. PV module is an integrated solution that is reliable and inexpensive. 2 figs.

  9. Temperature compensated photovoltaic array

    DOEpatents

    Mosher, Dan Michael

    1997-11-18

    A temperature compensated photovoltaic module (20) comprised of a series of solar cells (22) having a thermally activated switch (24) connected in parallel with several of the cells (22). The photovoltaic module (20) is adapted to charge conventional batteries having a temperature coefficient (TC) differing from the temperature coefficient (TC) of the module (20). The calibration temperatures of the switches (24) are chosen whereby the colder the ambient temperature for the module (20), the more switches that are on and form a closed circuit to short the associated solar cells (22). By shorting some of the solar cells (22) as the ambient temperature decreases, the battery being charged by the module (20) is not excessively overcharged at lower temperatures. PV module (20) is an integrated solution that is reliable and inexpensive.

  10. Advanced Rainbow Solar Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    Mardesich, Nick; Shields, Virgil

    2003-01-01

    Photovoltaic arrays of the rainbow type, equipped with light-concentrator and spectral-beam-splitter optics, have been investigated in a continuing effort to develop lightweight, high-efficiency solar electric power sources. This investigation has contributed to a revival of the concept of the rainbow photovoltaic array, which originated in the 1950s but proved unrealistic at that time because the selection of solar photovoltaic cells was too limited. Advances in the art of photovoltaic cells since that time have rendered the concept more realistic, thereby prompting the present development effort. A rainbow photovoltaic array comprises side-by-side strings of series-connected photovoltaic cells. The cells in each string have the same bandgap, which differs from the bandgaps of the other strings. Hence, each string operates most efficiently in a unique wavelength band determined by its bandgap. To obtain maximum energy-conversion efficiency and to minimize the size and weight of the array for a given sunlight input aperture, the sunlight incident on the aperture is concentrated, then spectrally dispersed onto the photovoltaic array plane, whereon each string of cells is positioned to intercept the light in its wavelength band of most efficient operation. The number of cells in each string is chosen so that the output potentials of all the strings are the same; this makes it possible to connect the strings together in parallel to maximize the output current of the array. According to the original rainbow photovoltaic concept, the concentrated sunlight was to be split into multiple beams by use of an array of dichroic filters designed so that each beam would contain light in one of the desired wavelength bands. The concept has since been modified to provide for dispersion of the spectrum by use of adjacent prisms. A proposal for an advanced version calls for a unitary concentrator/ spectral-beam-splitter optic in the form of a parabolic curved Fresnel-like prism

  11. Photovoltaic array loss mechanisms

    NASA Technical Reports Server (NTRS)

    Gonzalez, Charles

    1986-01-01

    Loss mechanisms which come into play when solar cell modules are mounted in arrays are identified. Losses can occur either from a reduction in the array electrical performance or with nonoptimal extraction of power from the array. Electrical performance degradation is caused by electrical mismatch, transmission losses from cell surface soiling and steep angle of reflectance, and electrical losses from field wiring resistance and the voltage drop across blocking diodes. The second type of loss, concerned with the operating points of the array, can involve nonoptimal load impedance and limiting the operating envelope of the array to specific ranges of voltage and current. Each of the loss mechanisms are discussed and average energy losses expected from soiling, steep reflectance angles and circuit losses are calculated.

  12. Wire Array Photovoltaics

    NASA Astrophysics Data System (ADS)

    Turner-Evans, Dan

    Over the past five years, the cost of solar panels has dropped drastically and, in concert, the number of installed modules has risen exponentially. However, solar electricity is still more than twice as expensive as electricity from a natural gas plant. Fortunately, wire array solar cells have emerged as a promising technology for further lowering the cost of solar. Si wire array solar cells are formed with a unique, low cost growth method and use 100 times less material than conventional Si cells. The wires can be embedded in a transparent, flexible polymer to create a free-standing array that can be rolled up for easy installation in a variety of form factors. Furthermore, by incorporating multijunctions into the wire morphology, higher efficiencies can be achieved while taking advantage of the unique defect relaxation pathways afforded by the 3D wire geometry. The work in this thesis shepherded Si wires from undoped arrays to flexible, functional large area devices and laid the groundwork for multijunction wire array cells. Fabrication techniques were developed to turn intrinsic Si wires into full p-n junctions and the wires were passivated with a-Si:H and a-SiNx:H. Single wire devices yielded open circuit voltages of 600 mV and efficiencies of 9%. The arrays were then embedded in a polymer and contacted with a transparent, flexible, Ni nanoparticle and Ag nanowire top contact. The contact connected >99% of the wires in parallel and yielded flexible, substrate free solar cells featuring hundreds of thousands of wires. Building on the success of the Si wire arrays, GaP was epitaxially grown on the material to create heterostructures for photoelectrochemistry. These cells were limited by low absorption in the GaP due to its indirect bandgap, and poor current collection due to a diffusion length of only 80 nm. However, GaAsP on SiGe offers a superior combination of materials, and wire architectures based on these semiconductors were investigated for multijunction

  13. FEMP Renewable Energy Fact Sheet: Photovoltaics

    SciTech Connect

    1999-10-01

    Photovoltaic energy systems, which convert sunlight to electricity, can meet many different needs in Federal facilities. This fact sheet describes how photovoltaic (PV) energy systems can be used to provide electricity for lighting, communications, refrigeration, fans, signs, pumps, drilling equipment, emergency power packs, and cathodic (corrosion) protection, among others. Applications for PV power in Federal facilities include staff housing, parking areas, campgrounds, marinas, visitor centers, roadside communications equipment, ranger stations, underground pipelines, irrigation and disinfecting systems, and disaster response units. PV systems are particularly suitable and cost-effective for facilities that now use diesel power or that are in remote areas far from electric power lines.

  14. Integrated residential photovoltaic array development

    NASA Technical Reports Server (NTRS)

    Shepard, N. F., Jr.

    1981-01-01

    The design details of an optimized integrated residential photovoltaic module/array are presented. This selected design features a waterproofing and mounting scheme which was devised to simplify the installation procedures by the avoidance of complex gasketed or caulked joints, while still maintaining a high confidence that the watertight integrity of the integral roofing surface will be achieved for the design lifetime of the system. The production and installation costs for the selected module/array design are reported for a range of annual production rates as a function of the cost of solar cells.

  15. Integrated residential photovoltaic array development

    NASA Astrophysics Data System (ADS)

    Royal, G. C., III

    1981-04-01

    Sixteen conceptual designs of residential photovoltaic arrays are described. Each design concept was evaluated by an industry advisory panel using a comprehensive set of technical, economic and institutional criteria. Key electrical and mechanical concerns that effect further array subsystem development are also discussed. Three integrated array design concepts were selected by the advisory panel for further optimization and development. From these concepts a single one will be selected for detailed analysis and prototype fabrication. The three concepts selected are: (1) An array of frameless panels/modules sealed in a T shaped zipper locking neoprene gasket grid pressure fitted into an extruded aluminum channel grid fastened across the rafters. (2) An array of frameless modules pressure fitted in a series of zipper locking EPDM rubber extrusions adhesively bonded to the roof. Series string voltage is developed using a set of integral tongue connectors and positioning blocks. (3) An array of frameless modules sealed by a silicone adhesive in a prefabricated grid of rigid tape and sheet metal attached to the roof.

  16. Integrated residential photovoltaic array development

    NASA Technical Reports Server (NTRS)

    Royal, G. C., III

    1981-01-01

    Sixteen conceptual designs of residential photovoltaic arrays are described. Each design concept was evaluated by an industry advisory panel using a comprehensive set of technical, economic and institutional criteria. Key electrical and mechanical concerns that effect further array subsystem development are also discussed. Three integrated array design concepts were selected by the advisory panel for further optimization and development. From these concepts a single one will be selected for detailed analysis and prototype fabrication. The three concepts selected are: (1) An array of frameless panels/modules sealed in a T shaped zipper locking neoprene gasket grid pressure fitted into an extruded aluminum channel grid fastened across the rafters. (2) An array of frameless modules pressure fitted in a series of zipper locking EPDM rubber extrusions adhesively bonded to the roof. Series string voltage is developed using a set of integral tongue connectors and positioning blocks. (3) An array of frameless modules sealed by a silicone adhesive in a prefabricated grid of rigid tape and sheet metal attached to the roof.

  17. Integrated residential photovoltaic array development

    NASA Astrophysics Data System (ADS)

    Shepard, N. F., Jr.

    1981-02-01

    An optimum integrated residential photovoltaic array/module is addressed. Nineteen existing or proposed systems intended for residential applications are described. Each of these systems is rated against a comprehensive set of evaluation criteria in an effort to formulate three module design concepts for further study and analysis. This evaluation led to a number of observations which are enumerated and should be considered in future module and array designs. Three module concepts are presented as baseline design approaches to be further analyzed and optimized. These options include: (1) a rectangular, direct mounted, shingle type module; (2) an integrally mounted module with nonconductive exposed elements; and (3) an aluminum framed, stand off module. Preliminary design drawings are presented for each of these module configurations.

  18. Integrated residential photovoltaic array development

    NASA Technical Reports Server (NTRS)

    Shepard, N. F., Jr.

    1981-01-01

    An optimum integrated residential photovoltaic array/module is addressed. Nineteen existing or proposed systems intended for residential applications are described. Each of these systems is rated against a comprehensive set of evaluation criteria in an effort to formulate three module design concepts for further study and analysis. This evaluation led to a number of observations which are enumerated and should be considered in future module and array designs. Three module concepts are presented as baseline design approaches to be further analyzed and optimized. These options include: (1) a rectangular, direct mounted, shingle type module; (2) an integrally mounted module with nonconductive exposed elements; and (3) an aluminum framed, stand off module. Preliminary design drawings are presented for each of these module configurations.

  19. Photovoltaic array mounting apparatus, systems, and methods

    DOEpatents

    West, Jack Raymond; Atchley, Brian; Hudson, Tyrus Hawkes; Johansen, Emil

    2016-01-05

    A photovoltaic array, including: (a) supports laid out on a surface in rows and columns; (b) photovoltaic modules positioned on top of the supports; and (c) fasteners connecting the photovoltaic modules to the supports, wherein the supports have an upper pedestal surface and a lower pedestal surface such that the photovoltaic modules are positioned at a non-horizontal angle when edges of the photovoltaic modules are positioned on top of the upper and lower pedestal surfaces, and wherein a portion of the fasteners rotate to lock the photovoltaic modules onto the supports.

  20. Photovoltaic array mounting apparatus, systems, and methods

    DOEpatents

    West, Jack Raymond; Atchley, Brian; Hudson, Tyrus Hawkes; Johansen, Emil

    2015-04-14

    A photovoltaic array, including: (a) supports laid out on a surface in rows and columns; (b) photovoltaic modules positioned on top of the supports; and (c) fasteners connecting the photovoltaic modules to the supports, wherein the supports have an upper pedestal surface and a lower pedestal surface such that the photovoltaic modules are positioned at a non-horizontal angle when edges of the photovoltaic modules are positioned on top of the upper and lower pedestal surfaces, and wherein a portion of the fasteners rotate to lock the photovoltaic modules onto the supports.

  1. III-V High-Efficiency Multijunction Photovoltaics (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet that includes scope, core competencies and capabilities, and contact/web information for III-V High-Efficiency Multijunction Photovoltaics at the National Center for Photovoltaics.

  2. Residential photovoltaic module and array requirements study

    NASA Technical Reports Server (NTRS)

    Nearhoof, S. L.; Oster, J. R.

    1979-01-01

    Design requirements for photovoltaic modules and arrays used in residential applications were identified. Building codes and referenced standards were reviewed for their applicability to residential photovoltaic array installations. Four installation types were identified - integral (replaces roofing), direct (mounted on top of roofing), stand-off (mounted away from roofing), and rack (for flat or low slope roofs, or ground mounted). Installation costs were developed for these mounting types as a function of panel/module size. Studies were performed to identify optimum module shapes and sizes and operating voltage cost drivers. It is concluded that there are no perceived major obstacles to the use of photovoltaic modules in residential arrays. However, there is no applicable building code category for residential photovoltaic modules and arrays and additional work with standards writing organizations is needed to develop residential module and array requirements.

  3. Space Environment Testing of Photovoltaic Array Systems

    NASA Technical Reports Server (NTRS)

    Phillips, Brandon; Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H.

    2015-01-01

    To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry.

  4. Flat-plate photovoltaic array design optimization

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1980-01-01

    An analysis is presented which integrates the results of specific studies in the areas of photovoltaic structural design optimization, optimization of array series/parallel circuit design, thermal design optimization, and optimization of environmental protection features. The analysis is based on minimizing the total photovoltaic system life-cycle energy cost including repair and replacement of failed cells and modules. This approach is shown to be a useful technique for array optimization, particularly when time-dependent parameters such as array degradation and maintenance are involved.

  5. Terminal System for Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    Maloney, T. J.

    1984-01-01

    Quick-connect terminal system provides electrical contact and physical alinement between adjacent photovoltaic modules. Dual-ended plugs connect adjacent modules; single-ended plugs connect bus cables. No tools required to insert plugs and no live terminals exposed before, during, or after connection.

  6. Integrated residential photovoltaic array development

    NASA Technical Reports Server (NTRS)

    Shepard, N. F., Jr.

    1981-01-01

    Three basic module design concepts were analyzed with respect to both production and installation costs. The results of this evaluation were used to synthesize a fourth design which incorporates the best features of these initial concepts to produce a module/array design approach which offers the promise of a substantial reduction in the installed cost of a residential array. A unique waterproofing and mounting scheme was used to reduce the cost of installing an integral array while still maintaining a high probability that the installed array will be watertight for the design lifetime of the system. This recommended concept will also permit the array to be mounted as a direct or stand-off installation with no changes to the module design.

  7. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Lenox, Carl J. S.; Culligan, Matthew; Danning, Matt

    2013-08-27

    A photovoltaic (PV) module including a PV device and a frame, The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  8. Photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Lenox, Carl J. S.; Culligan, Matthew; Danning, Matt

    2012-07-17

    A photovoltaic (PV) module including a PV device and a frame. The PV device has a PV laminate defining a perimeter and a major plane. The frame is assembled to and encases the laminate perimeter, and includes leading, trailing, and side frame members, and an arm that forms a support face opposite the laminate. The support face is adapted for placement against a horizontal installation surface, to support and orient the laminate in a non-parallel or tilted arrangement. Upon final assembly, the laminate and the frame combine to define a unitary structure. The frame can orient the laminate at an angle in the range of 3.degree.-7.degree. from horizontal, and can be entirely formed of a polymeric material. Optionally, the arm incorporates integral feature(s) that facilitate interconnection with corresponding features of a second, identically formed PV module.

  9. Mission applications for advanced photovoltaic solar arrays

    NASA Technical Reports Server (NTRS)

    Stella, Paul M.; West, John L.; Chave, Robert G.; Mcgee, David P.; Yen, Albert S.

    1990-01-01

    The suitability of the Advanced Photovoltaic Solar Array (APSA) for future space missions was examined by considering the impact on the spacecraft system in general. The lightweight flexible blanket array system was compared to rigid arrays and a radio-isotope thermoelectric generator (RTG) static power source for a wide range of assumed future earth orbiting and interplanetary mission applications. The study approach was to establish assessment criteria and a rating scheme, identify a reference mission set, perform the power system assessment for each mission, and develop conclusions and recommendations to guide future APSA technology development. The authors discuss the three selected power sources, the assessment criteria and rating definitions, and the reference missions. They present the assessment results in a convenient tabular format. It is concluded that the three power sources examined, APSA, conventional solar arrays, and RTGs, can be considered to complement each other. Each power technology has its own range of preferred applications.

  10. Photovoltaic array space power plus diagnostics experiment

    NASA Technical Reports Server (NTRS)

    Burger, D. R.

    1990-01-01

    The objective is to summarize the five years of hardware development and fabrication represented by the Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) Instrument. The original PASP Experiment requirements and background is presented along with the modifications which were requested to transform the PASP Experiment into the PASP Plus Instrument. The PASP Plus hardware and software is described. Test results for components and subsystems are given as well as final system tests. Also included are appendices which describe the major subsystems and present supporting documentation such as block diagrams, schematics, circuit board artwork, drawings, test procedures and test reports.

  11. Fault Analysis in Solar Photovoltaic Arrays

    NASA Astrophysics Data System (ADS)

    Zhao, Ye

    Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency and safety in PV systems. Conventional fault protection methods usually add fuses or circuit breakers in series with PV components. But these protection devices are only able to clear faults and isolate faulty circuits if they carry a large fault current. However, this research shows that faults in PV arrays may not be cleared by fuses under some fault scenarios, due to the current-limiting nature and non-linear output characteristics of PV arrays. First, this thesis introduces new simulation and analytic models that are suitable for fault analysis in PV arrays. Based on the simulation environment, this thesis studies a variety of typical faults in PV arrays, such as ground faults, line-line faults, and mismatch faults. The effect of a maximum power point tracker on fault current is discussed and shown to, at times, prevent the fault current protection devices to trip. A small-scale experimental PV benchmark system has been developed in Northeastern University to further validate the simulation conclusions. Additionally, this thesis examines two types of unique faults found in a PV array that have not been studied in the literature. One is a fault that occurs under low irradiance condition. The other is a fault evolution in a PV array during night-to-day transition. Our simulation and experimental results show that overcurrent protection devices are unable to clear the fault under "low irradiance" and "night-to-day transition". However, the overcurrent protection devices may work properly when the same PV fault occurs in daylight. As a result, a fault under "low irradiance" and "night-to-day transition" might be hidden in the PV array and become a potential hazard for system efficiency and reliability.

  12. Photovoltaic Array Space Power flight experiment plus diagnostics (PASP+) modules

    NASA Technical Reports Server (NTRS)

    Cooley, William T.; Adams, Steven F.; Reinhardt, Kitt C.; Piszczor, Michael F.

    1992-01-01

    The Photovoltaic Array Space Power Plus Diagnostics flight experiment (PASP+) subsumes twelve solar array modules which represent the state of the art in the space photovoltaic array industry. Each of the twelve modules individually feature specific photovoltaic technologies such as advanced semiconductor materials, multi-bandgap structures, lightweight array designs, advanced interconnect technologies, or concentrator array designs. This paper will describe each module in detail including the configuration, components, materials, anticipated on orbit performance, and some of the aspects of each array technology. The layout of each module and the photovoltaic cells or array cross section will be presented graphically. A discussion on the environmental constraints and materials selection will be included as well as a delineation of the differences between the modules and the baseline array configuration in its intended application.

  13. Photovoltaic array for Martian surface power

    NASA Technical Reports Server (NTRS)

    Appelbaum, J.; Landis, G. A.

    1992-01-01

    Missions to Mars will require electric power. A leading candidate for providing power is solar power produced by photovoltaic arrays. To design such a power system, detailed information on solar-radiation availability on the Martian surface is necessary. The variation of the solar radiation on the Martian surface is governed by three factors: (1) variation in Mars-Sun distance; (2) variation in solar zenith angle due to Martian season and time of day; and (3) dust in the Martian atmosphere. A major concern is the dust storms, which occur on both local and global scales. However, there is still appreciable diffuse sunlight available even at high opacity, so that solar array operation is still possible. Typical results for tracking solar collectors are also shown and compared to the fixed collectors. During the Northern Hemisphere spring and summer the isolation is relatively high, 2-5 kW-hr/sq m-day, due to the low optical depth of the Martian atmosphere. These seasons, totalling a full terrestrial year, are the likely ones during which manned mission will be carried out.

  14. Microprocessor-controlled photovoltaic-array loading unit

    SciTech Connect

    Russell, D.F.

    1982-08-01

    Described is a microprocessor-controlled test system in operation at the Photovoltaics Advanced Systems Test Facility located at Sandia National Laboratories. The test system is designed to measure the total energy output of photovoltaic arrays. The theory, installation, operation, and calibration of the test system are described.

  15. Feasibility Study of Solar Dome Encapsulation of Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The technical and economic advantages of using air-supported plastic enclosures to protect flat plate photovoltaic arrays are described. Conceptual designs for a fixed, latitude-tilt array and a fully tracking array were defined. Detailed wind loads and strength analyses were performed for the fixed array. Detailed thermal and power output analyses provided array performance for typical seasonal and extreme temperature conditions. Costs of each design as used in a 200 MWe central power station were defined from manufacturing and material cost estimates. The capital cost and cost of energy for the enclosed fixed-tilt array were lower than for the enclosed tracking array. The enclosed fixed-tilt array capital investment was 38% less, and the levelized bus bar energy cost was 26% less than costs for a conventional, glass-encapsulated array design. The predicted energy cost for the enclosed fixed array was 79 mills/kW-h for direct current delivered to the power conditioning units.

  16. Photovoltaic array with minimally penetrating rooftop support system

    DOEpatents

    Lenox, Carl J.S.

    2012-10-23

    A photovoltaic array including a plurality of photovoltaic assemblies and a plurality of mounting units. The mounting units each include an elongate rail and a plurality of leg assemblies. The rail is sized and configured to maintain a portion of at least two of the photovoltaic assemblies, with the leg assemblies extending from the rail in a spaced-apart fashion and terminating in a foot for placement against a rooftop structure for minimally penetration installation. Further, at least one of the leg assemblies can include a retractable leg. When the photovoltaic array is installed to a rooftop structure including a membrane intermittently secured to a rooftop deck, the retractable leg accommodates upward billowing of the membrane under windy conditions.

  17. Solar radiation on Mars: Stationary photovoltaic array

    NASA Technical Reports Server (NTRS)

    Appelbaum, J.; Sherman, I.; Landis, G. A.

    1993-01-01

    Solar energy is likely to be an important power source for surface-based operation on Mars. Photovoltaic cells offer many advantages. In this article we have presented analytical expressions and solar radiation data for stationary flat surfaces (horizontal and inclined) as a function of latitude, season and atmospheric dust load (optical depth). The diffuse component of the solar radiation on Mars can be significant, thus greatly affecting the optimal inclination angle of the photovoltaic surface.

  18. Array structure design handbook for stand alone photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Didelot, R. C.

    1980-01-01

    This handbook will permit the user to design a low-cost structure for a variety of photovoltaic system applications under 10 kW. Any presently commercially available photovoltaic modules may be used. Design alternatives are provided for different generic structure types, structural materials, and electric interfaces. The use of a hand-held calculator is sufficient to perform the necessary calculations for the array designs.

  19. Residential photovoltaic module and array requirements study, appendices

    NASA Technical Reports Server (NTRS)

    Nearhoof, S. L.; Oster, J. R.

    1979-01-01

    Regional building code variations, federal and city codes, and the national electric code are reviewed for their possible effects on the design of photovoltaic modules. Problems that photovoltaic arrays may impose on the insurability of residences are also discussed. Mounting configurations are developed for the modules, and grounding, wiring, terminal, and voltage requirements are established. Installation and materials costs are presented along with performance criteria.

  20. Photovoltaic properties of GaAs:Be nanowire arrays

    SciTech Connect

    Bouravleuv, A. D.; Beznasyuk, D. V.; Gilstein, E. P.; Tchernycheva, M.; Luna Bugallo, A. De; Rigutti, L.; Yu, L.; Proskuryakov, Yu.; Shtrom, I. V.; Timofeeva, M. A.; Samsonenko, Yu. B.; Khrebtov, A. I.; Cirlin, G.

    2013-06-15

    Arrays of GaAs:Be nanowires are synthesized by molecular beam epitaxy on GaAs(111)B substrates. Prototypes of photovoltaic converters in which the grown nanowire arrays are used as active layers are produced by means of successive photolithography, etching, and metallization processes. Studying the photovoltaic properties of the fabricated structures using a solar radiation simulator demonstrates that the solarenergy conversion efficiency is about 0.1%. The value of the efficiency recalculated with the area occupied by the p-type nanowires on the surface of the n-type GaAs substrate taken into account amounts to 1.1%.

  1. Photovoltaic array: Power conditioner interface characteristics

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. C.; Hill, G. M.; Ross, R. G., Jr.

    1982-01-01

    The electrical output (power, current, and voltage) of flat plate solar arrays changes constantly, due primarily to changes in cell temperature and irradiance level. As a result, array loads such as dc-to-ac power conditioners must be capable of accommodating widely varying input levels while maintaining operation at or near the maximum power point of the array. The array operating characteristics and extreme output limits necessary for the systematic design of array load interfaces under a wide variety of climatic conditions are studied. A number of interface parameters are examined, including optimum operating voltage, voltage energy, maximum power and current limits, and maximum open circuit voltage. The effect of array degradation and I-V curve fill factor or the array power conditioner interface is also discussed. Results are presented as normalized ratios of power conditioner parameters to array parameters, making the results universally applicable to a wide variety of system sizes, sites, and operating modes.

  2. Stretched Lens Array (SLA) Photovoltaic Concentrator Hardware Development and Testing

    NASA Technical Reports Server (NTRS)

    Piszczor, Michael; O'Neill, Mark J.; Eskenazi, Michael

    2003-01-01

    Over the past two years, the Stretched Lens Array (SLA) photovoltaic concentrator has evolved, under a NASA contract, from a concept with small component demonstrators to operational array hardware that is ready for space validation testing. A fully-functional four panel SLA solar array has been designed, built and tested. This paper will summarize the focus of the hardware development effort, discuss the results of recent testing conducted under this program and present the expected performance of a full size 7kW array designed to meet the requirements of future space missions.

  3. Wind loads on flat plate photovoltaic array fields

    NASA Technical Reports Server (NTRS)

    Miller, R. D.; Zimmerman, D. K.

    1981-01-01

    The results of an experimental analysis (boundary layer wind tunnel test) of the aerodynamic forces resulting from winds acting on flat plate photovoltaic arrays are presented. Local pressure coefficient distributions and normal force coefficients on the arrays are shown and compared to theoretical results. Parameters that were varied when determining the aerodynamic forces included tilt angle, array separation, ground clearance, protective wind barriers, and the effect of the wind velocity profile. Recommended design wind forces and pressures are presented, which envelop the test results for winds perpendicular to the array's longitudinal axis. This wind direction produces the maximum wind loads on the arrays except at the array edge where oblique winds produce larger edge pressure loads. The arrays located at the outer boundary of an array field have a protective influence on the interior arrays of the field. A significant decrease of the array wind loads were recorded in the wind tunnel test on array panels located behind a fence and/or interior to the array field compared to the arrays on the boundary and unprotected from the wind. The magnitude of this decrease was the same whether caused by a fence or upwind arrays.

  4. Development of photovoltaic array and module safety requirements

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Safety requirements for photovoltaic module and panel designs and configurations likely to be used in residential, intermediate, and large-scale applications were identified and developed. The National Electrical Code and Building Codes were reviewed with respect to present provisions which may be considered to affect the design of photovoltaic modules. Limited testing, primarily in the roof fire resistance field was conducted. Additional studies and further investigations led to the development of a proposed standard for safety for flat-plate photovoltaic modules and panels. Additional work covered the initial investigation of conceptual approaches and temporary deployment, for concept verification purposes, of a differential dc ground-fault detection circuit suitable as a part of a photovoltaic array safety system.

  5. Glass for low-cost photovoltaic solar arrays

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.

    1980-01-01

    Various aspects of glass encapsulation that are important for the designer of photovoltaic systems are discussed. Candidate glasses and available information defining the state of the art of glass encapsulation materials and processes for automated, high volume production of terrestrial photovoltaic devices and related applications are presented. The criteria for consideration of the glass encapsulation systems were based on the low-cost solar array project goals for arrays: (1) a low degradation rate, (2) high reliability, (3) an efficiency greater than 10 percent, (4) a total array price less than $500/kW, and (5) a production capacity of 500,000 kW/yr. The glass design areas discussed include the types of glass, sources and costs, physical properties, and glass modifications, such as antireflection coatings.

  6. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    NASA Technical Reports Server (NTRS)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  7. Glass for low-cost photovoltaic solar arrays

    SciTech Connect

    Bouquet, F.L.

    1980-02-01

    In photovoltaic systems, the encapsulant material that protects the solar cells should be highly transparent and very durable. Glass satisfies these two criteria and is considered a primary candidate for low-cost, photovoltaic encapsulation systems. In this report, various aspects of glass encapsulation are treated that are important for the designer of photovoltaic systems. Candidate glasses and available information defining the state of the art of glass encapsulation materials and processes for automated, high volume production of terrestrial photovoltaic devices and related applications are presented. The criteria for consideration of the glass encapsulation systems were based on the LSA (Low-cost Solar Array) Project goals for arrays: (a) a low degradation rate, (b) high reliability, (c) an efficiency greater than 10 percent, (d) a total array price less than $500/kW, and (e) a production capacity of 5 x 10/sup 5/ kW/yr. The glass design areas treated herein include the types of glass, sources and costs, physical properties and glass modifications, such as antireflection coatings. 78 references.

  8. Design of photovoltaic central power station concentrator array

    SciTech Connect

    Not Available

    1984-02-01

    A design for a photovoltaic central power station using tracking concentrators has been developed. The 100 MW plant is assumed to be located adjacent to the Saguaro Power Station of Arizona Public Service. The design assumes an advanced Martin Marietta two-axis tracking fresnel lens concentrator. The concentrators are arrayed in 5 MW subfields, each with its own power conditioning unit. The photovoltaic plant output is connected to the existing 115 kV switchyard. The site specific design allows detailed cost estimates for engineering, site preparation, and installation. Collector and power conditioning costs have been treated parametrically.

  9. Wind loads on flat plate photovoltaic array fields (nonsteady winds)

    NASA Technical Reports Server (NTRS)

    Miller, R. D.; Zimmerman, D. K.

    1981-01-01

    Techniques to predict the dynamic response and the structural dynamic loads of flat plate photovoltaic arrays due to wind turbulence were analyzed. Guidelines for use in predicting the turbulent portion of the wind loading on future similar arrays are presented. The dynamic response and the loads dynamic magnification factor of the two array configurations are similar. The magnification factors at a mid chord and outer chord location on the array illustrated and at four points on the chord are shown. The wind tunnel test experimental rms pressure coefficient on which magnification factors are based is shown. It is found that the largest response and dynamic magnification factor occur at a mid chord location on an array and near the trailing edge. A technique employing these magnification factors and the wind tunnel test rms fluctuating pressure coefficients to calculate design pressure loads due to wind turbulence is presented.

  10. Broadband-antireflective hybrid nanopillar array for photovoltaic application

    SciTech Connect

    Watanabe, Keiji Yamamoto, Jiro; Tsuchiya, Ryuta

    2015-08-28

    Subwavelength structures such as nanopillars, nanoholes, and nanodomes have recently attracted considerable attention as antireflective structures for solar cells. Recent studies on the optical property of nanopillar array revealed that the reflection minimum is related to the diameter, the pitch, and the height of nanopillars. Here, we investigate the “hybrid” nanopillar array, which is composed of different diameters of nanopillars. Finite differential time domain simulations revealed that the photogeneration in a hybrid nanopillar array is spatially heterogeneous: carriers are generated mainly in the narrower pillars for short-wavelength incident light and in the thicker pillars for long-wavelength light, respectively. Hybrid silicon nanopillar arrays fabricated by using electron beam lithography and dry etching show excellent broadband antireflection property. Hybrid nanopillar array is thus highly promising for next-generation antireflection for photovoltaic applications.

  11. Ballasted photovoltaic module and module arrays

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt

    2011-11-29

    A photovoltaic (PV) module assembly including a PV module and a ballast tray. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes an arm. The ballast tray is adapted for containing ballast and is removably associated with the PV module in a ballasting state where the tray is vertically under the PV laminate and vertically over the arm to impede overt displacement of the PV module. The PV module assembly can be installed to a flat commercial rooftop, with the PV module and the ballast tray both resting upon the rooftop. In some embodiments, the ballasting state includes corresponding surfaces of the arm and the tray being spaced from one another under normal (low or no wind) conditions, such that the frame is not continuously subjected to a weight of the tray.

  12. Photovoltaic array mounting apparatus, systems, and methods

    DOEpatents

    West, John Raymond; Atchley, Brian; Hudson, Tyrus Hawkes; Johansen, Emil

    2014-12-02

    An apparatus for mounting a photovoltaic (PV) module on a surface, including a support with an upper surface, a lower surface, tabs, one or more openings, and a clip comprising an arm and a notch, where the apparatus resists wind forces and seismic forces and creates a grounding electrical bond between the PV module, support, and clip. The invention further includes a method for installing PV modules on a surface that includes arranging supports in rows along an X axis and in columns along a Y axis on a surface such that in each row the distance between two neighboring supports does not exceed the length of the longest side of a PV module and in each column the distance between two neighboring supports does not exceed the length of the shortest side of a PV module.

  13. Wind Loads on Flat Plate Photovoltaic Array Fields

    NASA Technical Reports Server (NTRS)

    Miller, R.; Zimmerman, D.

    1979-01-01

    The aerodynamic forces resulting from winds acting on flat plate photovoltaic arrays were investigated. Local pressure distributions and total aerodynamic forces on the arrays are shown. Design loads are presented to cover the conditions of array angles relative to the ground from 20 deg to 60 deg, variable array spacings, a ground clearance gap up to 1.2 m (4 ft) and array slant heights of 2.4 m (8 ft) and 4.8 m (16 ft). Several means of alleviating the wind loads on the arrays are detailed. The expected reduction of the steady state wind velocity with the use of fences as a load alleviation device are indicated to be in excess of a factor of three for some conditions. This yields steady state wind load reductions as much as a factor of ten compared to the load incurred if no fence is used to protect the arrays. This steady state wind load reduction is offset by the increase in turbulence due to the fence but still an overall load reduction of 2.5 can be realized. Other load alleviation devices suggested are the installation of air gaps in the arrays, blocking the flow under the arrays and rounding the edges of the array. A wind tunnel test plan to supplement the theoretical study and to evaluate the load alleviation devices is outlined.

  14. Integral assembly of photovoltaic arrays using glass

    NASA Technical Reports Server (NTRS)

    Younger, P. R.; Kirkpatrick, A. R.; Maxwell, H. G.; Holtze, R. F.

    1978-01-01

    For a number of reasons glass is an excellent material for encapsulation of solar cell arrays. Glass can be readily available at relatively low cost. It exhibits excellent stability against degradation by solar ultraviolet illumination and atmospheric pollutants. A superior approach results if glass is employed directly as an integral encapsulant without secondary organic materials. A description is presented of a electrostatic bonding process which is being developed for integral assembly of glass encapsulated arrays. Solar cells are placed in contact with the glass surface, temperature is raised until the glass becomes ionically conductive, and an electric field is applied to initiate the bonding action. Silicon solar cells up to 3 inches in diameter have been integrally bonded without degradation.

  15. Forecasting photovoltaic array power production subject to mismatch losses

    SciTech Connect

    Picault, D.; Raison, B.; Bacha, S.; de la Casa, J.; Aguilera, J.

    2010-07-15

    The development of photovoltaic (PV) energy throughout the world this last decade has brought to light the presence of module mismatch losses in most PV applications. Such power losses, mainly occasioned by partial shading of arrays and differences in PV modules, can be reduced by changing module interconnections of a solar array. This paper presents a novel method to forecast existing PV array production in diverse environmental conditions. In this approach, field measurement data is used to identify module parameters once and for all. The proposed method simulates PV arrays with adaptable module interconnection schemes in order to reduce mismatch losses. The model has been validated by experimental results taken on a 2.2 kW{sub p} plant, with three different interconnection schemes, which show reliable power production forecast precision in both partially shaded and normal operating conditions. Field measurements show interest in using alternative plant configurations in PV systems for decreasing module mismatch losses. (author)

  16. Voltage-current-power meter for photovoltaic solar arrays

    NASA Technical Reports Server (NTRS)

    Ross, Ronald G. (Inventor)

    1979-01-01

    A meter is disclosed for measuring the voltage, current, and power (VIP) parameters of a photovoltaic solar array, or array module, under sunlight operating conditions utilizing a variable load connected across the array and controlled by a voltage regulator which responds to the difference between the output voltage of the array and a programmed test voltage from a source which generates a single ramp voltage for measuring and recording current as a function of voltage, repeated ramp voltages at a high rate for peak output measurements or a DC voltage for VIP measurements at selected points on the I-V characteristic curve of the array. The voltage signal from a current sensing element, such as a shunt resistor in series with the variable load, is compared with the output current of a reference solar cell to provide a normalizing signal to be added to the signal from the current-sensing element in order to provide a record of array current as a function of array voltage, i.e., for all load conditions from short circuit to open circuit. As the normalized current is thus measured, an analog multiplier multiplies the array voltage and normalized current to provide a measurement of power. Switches are provided to selectively connect the power, P, current, I, or voltage, V, to a meter, directly or through a peak detector. At the same time any one of the parameters V, I and P may be recorded as a function of any other parameter.

  17. Thin-Film Photovoltaic Solar Array Parametric Assessment

    NASA Technical Reports Server (NTRS)

    Hoffman, David J.; Kerslake, Thomas W.; Hepp, Aloysius F.; Jacobs, Mark K.; Ponnusamy, Deva

    2000-01-01

    This paper summarizes a study that had the objective to develop a model and parametrically determine the circumstances for which lightweight thin-film photovoltaic solar arrays would be more beneficial, in terms of mass and cost, than arrays using high-efficiency crystalline solar cells. Previous studies considering arrays with near-term thin-film technology for Earth orbiting applications are briefly reviewed. The present study uses a parametric approach that evaluated the performance of lightweight thin-film arrays with cell efficiencies ranging from 5 to 20 percent. The model developed for this study is described in some detail. Similar mass and cost trends for each array option were found across eight missions of various power levels in locations ranging from Venus to Jupiter. The results for one specific mission, a main belt asteroid tour, indicate that only moderate thin-film cell efficiency (approx. 12 percent) is necessary to match the mass of arrays using crystalline cells with much greater efficiency (35 percent multi-junction GaAs based and 20 percent thin-silicon). Regarding cost, a 12 percent efficient thin-film array is projected to cost about half is much as a 4-junction GaAs array. While efficiency improvements beyond 12 percent did not significantly further improve the mass and cost benefits for thin-film arrays, higher efficiency will be needed to mitigate the spacecraft-level impacts associated with large deployed array areas. A low-temperature approach to depositing thin-film cells on lightweight, flexible plastic substrates is briefly described. The paper concludes with the observation that with the characteristics assumed for this study, ultra-lightweight arrays using efficient, thin-film cells on flexible substrates may become a leading alternative for a wide variety of space missions.

  18. Apparatus and method for maximizing power delivered by a photovoltaic array

    DOEpatents

    Muljadi, Eduard; Taylor, Roger W.

    1998-01-01

    A method and apparatus for maximizing the electric power output of a photovoltaic array connected to a battery where the voltage across the photovoltaic array is adjusted through a range of voltages to find the voltage across the photovoltaic array that maximizes the electric power generated by the photovoltaic array and then is held constant for a period of time. After the period of time has elapsed, the electric voltage across the photovoltaic array is again adjusted through a range of voltages and the process is repeated. The electric energy and the electric power generated by the photovoltaic array is delivered to the battery which stores the electric energy and the electric power for later delivery to a load.

  19. Apparatus and method for maximizing power delivered by a photovoltaic array

    DOEpatents

    Muljadi, E.; Taylor, R.W.

    1998-05-05

    A method and apparatus for maximizing the electric power output of a photovoltaic array connected to a battery where the voltage across the photovoltaic array is adjusted through a range of voltages to find the voltage across the photovoltaic array that maximizes the electric power generated by the photovoltaic array and then is held constant for a period of time. After the period of time has elapsed, the electric voltage across the photovoltaic array is again adjusted through a range of voltages and the process is repeated. The electric energy and the electric power generated by the photovoltaic array is delivered to the battery which stores the electric energy and the electric power for later delivery to a load. 20 figs.

  20. PASP, a high voltage array/plasma interaction experiment. [Photovoltaic Array Space Power

    NASA Technical Reports Server (NTRS)

    Burger, Dale R.

    1991-01-01

    The author discusses the photovoltaic array space power (PASP) experiment, which is designed to obtain data on the interaction between high-voltage photovoltaic arrays and the polar, low-earth plasma environment. Up to six small test arrays (three each of planar and concentrator designs) can be voltage biased over a range of +/- 500 V. During the bias voltage sequence, the array current leakage is measured and array arc events are monitored. If any arcing occurs the arc characteristics will be measured by a transient pulse monitor. An emitter is included to allow voltage bias to be applied to a plasma-charged or uncharged spacecraft. Similarly, the frames of the concentrator arrays can be left floating or can be tied to the negative array terminal. An environmental data scan is made before each bias voltage sequence. This scan collects information on the plasma, array-current-versus-voltage curves, and neutral particle partial pressure. The requirement for high voltages created problems which were met by circuit isolation and logical fault protection.

  1. A photovoltaic catenary-tent array for the Martian surface

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Appelbaum, J.; Crutchik, M.

    1993-01-01

    To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity, a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shading which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global irradiance on the array. The PV blanket shape and structure dimensions were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for three types of PV blankets (silicon, gallium arsenide over germanium, and amorphous silicon) and two types of structural materials (carbon composite and arimid fiber composite). The results show that the catenary shape of the PV blanket corresponding to zero end angle at the base with respect to the horizontal results in the highest specific power. The tent angle is determined by optimizing the specific mass and the output power for maximum specific power. The combination of carbon fiber structural material and amorphous silicon blanket produces the highest specific power.

  2. A photovoltaic catenary-tent array for the Martian surface

    NASA Astrophysics Data System (ADS)

    Colozza, Anthony J.; Appelbaum, J.; Crutchik, M.

    1993-05-01

    To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity, a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shading which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global irradiance on the array. The PV blanket shape and structure dimensions were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for three types of PV blankets (silicon, gallium arsenide over germanium, and amorphous silicon) and two types of structural materials (carbon composite and arimid fiber composite). The results show that the catenary shape of the PV blanket corresponding to zero end angle at the base with respect to the horizontal results in the highest specific power. The tent angle is determined by optimizing the specific mass and the output power for maximum specific power. The combination of carbon fiber structural material and amorphous silicon blanket produces the highest specific power.

  3. Planetary and deep space requirements for photovoltaic solar arrays

    NASA Astrophysics Data System (ADS)

    Bankston, C. P.; Bennett, R. B.; Stella, P. M.

    1995-10-01

    In the past 25 years, the majority of interplanetary spacecraft have been powered by nuclear sources. However, as the emphasis on smaller, low cost missions gains momentum, the majority of missions now being planned will use photovoltaic solar arrays. This will present challenges to the solar array builders, inasmuch as planetary requirements usually differ from earth orbital requirements. In addition, these requirements often differ greatly, depending on the specific mission; for example, inner planets vs. outer planets, orbiters vs. flybys, spacecraft vs. landers, and so on. Also, the likelihood of electric propulsion missions will influence the requirements placed on solar array developers. The paper will discuss representative requirements for a range of planetary missions now in the planning stages. Insofar as inner planets are concerned, a Mercury orbiter is being studied with many special requirements. Solar arrays would be exposed to high temperatures and a potentially high radiation environment, and will need to be increasingly pointed off sun as the vehicle approaches Mercury. Identification and development of cell materials and arrays at high incidence angles will be critical to the design. Missions to the outer solar system that have been studied include a Galilean orbiter and a flight to the Kuiper belt. While onboard power requirements would be small (as low as 10 watts), the solar intensity will require relatively large array areas. As a result, such missions will demand extremely compact packaging and low mass structures to conform to launch vehicle constraints. In turn, the large are, low mass designs will impact allowable spacecraft loads. Inflatable array structures, with and without concentration, and multiband gap cells will be considered if available. In general, the highest efficiency cell technologies operable under low intensity, low temperature conditions are needed. Solar arrays will power missions requiring as little as approximately 100

  4. Planetary and deep space requirements for photovoltaic solar arrays

    NASA Technical Reports Server (NTRS)

    Bankston, C. P.; Bennett, R. B.; Stella, P. M.

    1995-01-01

    In the past 25 years, the majority of interplanetary spacecraft have been powered by nuclear sources. However, as the emphasis on smaller, low cost missions gains momentum, the majority of missions now being planned will use photovoltaic solar arrays. This will present challenges to the solar array builders, inasmuch as planetary requirements usually differ from earth orbital requirements. In addition, these requirements often differ greatly, depending on the specific mission; for example, inner planets vs. outer planets, orbiters vs. flybys, spacecraft vs. landers, and so on. Also, the likelihood of electric propulsion missions will influence the requirements placed on solar array developers. The paper will discuss representative requirements for a range of planetary missions now in the planning stages. Insofar as inner planets are concerned, a Mercury orbiter is being studied with many special requirements. Solar arrays would be exposed to high temperatures and a potentially high radiation environment, and will need to be increasingly pointed off sun as the vehicle approaches Mercury. Identification and development of cell materials and arrays at high incidence angles will be critical to the design. Missions to the outer solar system that have been studied include a Galilean orbiter and a flight to the Kuiper belt. While onboard power requirements would be small (as low as 10 watts), the solar intensity will require relatively large array areas. As a result, such missions will demand extremely compact packaging and low mass structures to conform to launch vehicle constraints. In turn, the large are, low mass designs will impact allowable spacecraft loads. Inflatable array structures, with and without concentration, and multiband gap cells will be considered if available. In general, the highest efficiency cell technologies operable under low intensity, low temperature conditions are needed. Solar arrays will power missions requiring as little as approximately 100

  5. A photovoltaic catenary-tent array for the Martian surface

    NASA Astrophysics Data System (ADS)

    Crutchik, M.; Colozza, Anthony J.; Appelbaum, J.

    1993-08-01

    To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shadowing which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global radiation on the array. The PV blanket shape and structure dimension were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for four types of PV blankets (Si, GaAs/Ge, GaAs CLEFT, and amorphous Si) and four types of structure materials (Carbon composite, Aramid Fiber composite, Aluminum, and Magnesium). The results show that the catenary shape of the PV blanket, which produces the highest specific power, corresponds to zero end angle at the base with respect to the horizontal. The tent angle is determined by the combined effect of the array structure specific mass and the PV blanket output power. The combination of carbon composite structural material and GaAs CLEFT solar cells produce the highest specific power. The study was carried out for two sites on Mars corresponding to the Viking Lander locations. The designs were also compared for summer, winter, and yearly operation.

  6. A photovoltaic catenary-tent array for the Martian surface

    NASA Technical Reports Server (NTRS)

    Crutchik, M.; Colozza, Anthony J.; Appelbaum, J.

    1993-01-01

    To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shadowing which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global radiation on the array. The PV blanket shape and structure dimension were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for four types of PV blankets (Si, GaAs/Ge, GaAs CLEFT, and amorphous Si) and four types of structure materials (Carbon composite, Aramid Fiber composite, Aluminum, and Magnesium). The results show that the catenary shape of the PV blanket, which produces the highest specific power, corresponds to zero end angle at the base with respect to the horizontal. The tent angle is determined by the combined effect of the array structure specific mass and the PV blanket output power. The combination of carbon composite structural material and GaAs CLEFT solar cells produce the highest specific power. The study was carried out for two sites on Mars corresponding to the Viking Lander locations. The designs were also compared for summer, winter, and yearly operation.

  7. Silicon Microwire Arrays for Photoelectrochemical and Photovoltaic Applications

    NASA Astrophysics Data System (ADS)

    Warren, Emily Lowell

    Si microwire (Si MW) arrays grown by the vapor-liquid-solid (VLS) process are promising materials for next-generation solar energy devices. High-aspect-ratio semiconductor structures have attracted recent interest as solar absorber materials because their radial geometry decouples the direction of light absorption and carrier collection, enabling the use of materials with shorter minority-carrier diffusion lengths than would be acceptable in a planar geometry. The VLS growth process is a low-cost deposition technique, which can be used to fabricate flexible, high-performance semiconductor materials. Si MW arrays have been investigated as an inexpensive alternative to wafer-based solar photovoltaics for low- cost electricity generation. Another potential application is to use these vertically oriented wire arrays as photocathodes of a solar fuel conversion devices, where instead of producing electricity, sunlight is used to directly drive a fuel-forming reaction (e.g., splitting water to form O 2 and H2). The high aspect ratio of the Si MW arrays provides a large surface area for the integration of fuel-forming catalysts, allowing for the development of a low-cost, scalable, energy storage technology. This thesis discusses the fabrication and photoelectrochemical characterization of Si MWs grown by the VLS process, focusing on the use of these wire arrays as hydrogen- evolving photocathodes for solar water-splitting. To optimize such a device it is important to balance all of the factors that will affect performance: light absorption, band energetics, attainable open circuit voltage, and catalysis. First, we characterize the electrical performance of the wire arrays using regenerative photoelectrochemistry to understand the material quality and band energetics at the Si/water interface. We demonstrate the fabrication of H2-evolving photocathodes using p-n junction Si MW arrays and earth-abundant Ni-Mo alloy hydrogen evolution catalysts. We then investigate modifying

  8. Glass fiber reinforced concrete for terrestrial photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Maxwell, H.

    1979-01-01

    The use of glass-fiber-reinforced concrete (GRC) as a low-cost structural substrate for terrestrial solar cell arrays is discussed. The properties and fabrication of glass-reinforced concrete structures are considered, and a preliminary design for a laminated solar cell assembly built on a GRC substrate is presented. A total cost for such a photovoltaic module, composed of a Korad acrylic plastic film front cover, an aluminum foil back cover, an ethylene/vinyl acetate pottant/adhesive and a cotton fabric electrical isolator in addition to the GRC substrate, of $9.42/sq m is projected, which is less than the $11.00/sq m cost goal set by the Department of Energy. Preliminary evaluations are concluded to have shown the design capabilities and cost effectiveness of GRC; however, its potential for automated mass production has yet to be evaluated.

  9. Solar cell array design handbook - The principles and technology of photovoltaic energy conversion

    NASA Technical Reports Server (NTRS)

    Rauschenbach, H. S.

    1980-01-01

    Photovoltaic solar cell array design and technology for ground-based and space applications are discussed from the user's point of view. Solar array systems are described, with attention given to array concepts, historical development, applications and performance, and the analysis of array characteristics, circuits, components, performance and reliability is examined. Aspects of solar cell array design considered include the design process, photovoltaic system and detailed array design, and the design of array thermal, radiation shielding and electromagnetic components. Attention is then given to the characteristics and design of the separate components of solar arrays, including the solar cells, optical elements and mechanical elements, and the fabrication, testing, environmental conditions and effects and material properties of arrays and their components are discussed.

  10. Space Photovoltaic Research and Technology 1985: High Efficiency, Space Environment, and Array Technology

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The seventh NASA Conference on Space Photovoltaic Research and Technology was held at NASA Lewis Research Center, Cleveland, Ohio, from 30 April until 2 May 1985. Its purpose was to assess the progress made, the problems remaining, and future strategy for space photovoltaic research. Particular emphasis was placed on high efficiency, space environment, and array technology.

  11. Report of an exploratory study: safety and liability considerations for photovoltaic modules/panels, Low Cost Solar Array Project

    SciTech Connect

    Weinstein, A.S.; Meeker, D.G.

    1981-01-01

    Product safety and product liability considerations are explored for photovoltaic module/array devices. A general review of photovoltaic literature was made using computerized literature searches. A literature search was also made of relevant legal material as it applies to design. Recommendations are made to minimize or eliminate perceived hazards in manufacture and use of a photovoltaic module/array. (MHR)

  12. Space Photovoltaic Research and Technology 1986. High Efficiency, Space Environment, and Array Technology

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The conference provided a forum to assess the progress made, the problems remaining, and the strategy for the future of photovoltaic research. Cell research and technology, space environmental effects, array technology and applications were discussed.

  13. Commercial/industrial photovoltaic module and array requirement study. Low-cost solar array project engineering area

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Design requirements for photovoltaic modules and arrays used in commercial and industrial applications were identified. Building codes and referenced standards were reviewed for their applicability to commercial and industrial photovoltaic array installation. Four general installation types were identified - integral (replaces roofing), direct (mounted on top of roofing), stand-off (mounted away from roofing), and rack (for flat or low slope roofs, or ground mounted). Each of the generic mounting types can be used in vertical wall mounting systems. This implies eight mounting types exist in the commercial/industrial sector. Installation costs were developed for these mounting types as a function of panel/module size. Cost drivers were identified. Studies were performed to identify optimum module shapes and sizes and operating voltage cost drivers. The general conclusion is that there are no perceived major obstacles to the use of photovoltaic modules in commercial/industrial arrays.

  14. Flight Experience from Space Photovoltaic Concentrator Arrays and its Implication on Terrestrial Concentrator Systems

    NASA Technical Reports Server (NTRS)

    Piszczor, Michael F., Jr.

    2003-01-01

    Nearly all photovoltaic solar arrays flown in space have used a planar (non- concentrating) design. However, there have been a few notable exceptions where photovoltaic concentrators have been tested and used as the mission s primary power source. Among these are the success experienced by the SCARLET (Solar Concentrator Array with Refractive Linear Element Technology) concept used to power NASA's Deep Space 1 mission and the problems encountered by the original Boeing 702 reflective trough concentrator design. This presentation will give a brief overview of past photovoltaic concentrator systems that have flown in space, specifically addressing the valuable lessons learned from flight experience, and other viable concentrator concepts that are being proposed for the future. The general trends of this flight experience will be noted and discussed with regard to its implications on terrestrial photovoltaic concentrator designs.

  15. Safety-related requirements for photovoltaic modules and arrays

    NASA Technical Reports Server (NTRS)

    Levins, A.; Smoot, A.; Wagner, R.

    1984-01-01

    Safety requirements for photovoltaic module and panel designs and configurations for residential, intermediate, and large scale applications are investigated. Concepts for safety systems, where each system is a collection of subsystems which together address the total anticipated hazard situation, are described. Descriptions of hardware, and system usefulness and viability are included. A comparison of these systems, as against the provisions of the 1984 National Electrical Code covering photovoltaic systems is made. A discussion of the Underwriters Laboratory UL investigation of the photovoltaic module evaluated to the provisions of the proposed UL standard for plat plate photovoltaic modules and panels is included. Grounding systems, their basis and nature, and the advantages and disadvantages of each are described. The meaning of frame grounding, circuit groundings, and the type of circuit ground are covered.

  16. Design of a photovoltaic central power station: flat-plate array

    SciTech Connect

    Not Available

    1984-02-01

    A design for a photovoltaic central power station using fixed flat-panel arrays has been developed. The 100 MW plant is assumed to be located adjacent to the Saguaro Power Station of Arizona Public Service. The design assumes high-efficiency photovoltaic modules using dendritic web cells. The modules are arranged in 5 MW subfields, each with its own power conditioning unit. The photovoltaic output is connected to the existing 115 kV utility switchyard. The site specific design allows detailed cost estimates for engineering, site preparation, and installation. Collector and power conditioning costs have been treated parametrically.

  17. Design and economics of a photovoltaic concentrator array for off-grid applications

    NASA Astrophysics Data System (ADS)

    Maish, A. B.; Rios, M., Jr.

    1982-09-01

    The array design and expected operation of a photovoltaic concentrator are discussed. A second generation stand alone 680 W/sub p/ photovoltaic (PV) concentrating array for low power, nongrid connected applications was designed. The array consists of six passive cooled point focus Fresnel lens concentrating modules on a two axis polar mount tracking structure. The new array design incorporates several major improvements to the first generation design. These include 50% more array area and a control system which allows unattended, fully automatic operation. The life cycle energy costs are calculated and compared to the equivalent energy costs of a 3 kW diesel electric generator set and an equivalent flat panel PV system.

  18. SCARLET Photovoltaic Concentrator Array Selected for Flight Under NASA's New Millennium Program

    NASA Technical Reports Server (NTRS)

    Piszczor, Michael F., Jr.

    1997-01-01

    The NASA Lewis Research Center continues to demonstrate its expertise in the development and implementation of advanced space power systems. For example, during the past year, the NASA New Millennium Program selected the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) photovoltaic array as the power system for its Deep Space-1 (DS-1) mission. This Jet Propulsion Laboratory (JPL) managed DS-1 mission, which represents the first operational flight of a photovoltaic concentrator array, will provide a baseline for the use of this technology in a variety of future government and commercial applications. SCARLET is a joint NASA Lewis/Ballistic Missile Defense Organization program to develop advanced photovoltaic array technology that uses a unique refractive concentrator design to focus sunlight onto a line of photovoltaic cells located below the optical element. The general concept is based on previous work conducted at Lewis under a Small Business Innovation Research (SBIR) contract with AEC-Able Engineering, Inc., for the Multiple Experiments to Earth Orbit and Return (METEOR) spacecraft. The SCARLET II design selected by the New Millennium Program is a direct adaptation of the smaller SCARLET I array built for METEOR. Even though SCARLET I was lost during a launch failure in October 1995, the hardware (designed, built, and flight qualified within 6 months) provided invaluable information and experience that led to the selection of this technology as the primary power source for DS-1.

  19. NREL Determines Better Testing Methods for Photovoltaic Module Durability (Fact Sheet), NREL Highlights, Research & Development

    SciTech Connect

    Not Available

    2011-11-01

    NREL discoveries will enable manufacturers to produce more robust photovoltaic modules. Over the past decade, some photovoltaic (PV) modules have experienced power losses because of the system voltage stress that modules experience in fielded arrays. This is partly because qualification tests and standards do not adequately evaluate the durability of modules that undergo the long-term effects of high voltage. Scientists at the National Renewable Energy Laboratory (NREL) tried various testing methods and stress levels to demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. The results of these accelerated tests, along with outdoor testing, were used to estimate the acceleration factors needed to more accurately evaluate the durability of modules to system voltage stress. NREL was able to determine stress factors, levels, and methods for testing based on the stresses experienced by modules in the field. These results, in combination with those in the literature, suggest that constant stress with humidity and system voltage is more damaging than stress applied intermittently or with periods of recovery comprising hot and dry conditions or alternating bias in between. NREL has determined some module constructions to be extremely durable to PID. These findings will help the manufacturers of PV materials and components produce more durable products that better satisfy their customers. NREL determined that there is rapid degradation of some PV modules under system voltage stress and evaluated degradation rates in the field to develop more accurate accelerated testing methods. PV module manufacturers will be better able to choose robust materials and durable designs and guarantee sturdier, longer-lasting products. As PV modules become more durable, and thus more efficient over the long term, the risks and the cost of PV power will be reduced.

  20. Simplified design guide for estimating photovoltaic flat array and system performance

    SciTech Connect

    Evans, D.L.; Facinelli, W.A.; Koehler, L.P.

    1981-03-01

    Simplified, non-computer based methods are presented for predicting photovoltaic array and system performance. The array performance prediction methods are useful for calculating the potential output of passively cooled, flat, south facing max-power tracked arrays. A solar/weather data base for 97 different US and US affiliated stations is provided to aid in these calculations. Also, performance estimates can be made for photovoltaic systems (array, battery, power conditioner) that are backed-up by non-solar reserves capable of meeting the load when the solar system cannot. Such estimates can be made for a total of 41 different sinusoidal, unimodal, and bimodal diurnal load profiles from appropriate graphs included. These allow easy determination of the fraction of the load met by the solar photovoltaic system as a function of array size and (dedicated) battery storage capacity. These performance graphs may also be used for systems without battery storage. Use of array manufacturer's specification sheet data is discussed. Step-by-step procedures, along with suggested worksheets, are provided for carrying out the necessary calculations.

  1. Proceedings of the Flat-Plate Solar Array Project Research Forum on Photovoltaic Metallization Systems

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A photovoltaic Metallization Research forum, under the sponsorship of the Flat-Plate Solar Array Project consisted of five sessions, covering: (1) the current status of metallization systems, (2) system design, (3) thick-film metallization, (4) advanced techniques, and (5) future metallization challenges.

  2. Assessment of low-cost manufacturing process sequences. [photovoltaic solar arrays

    NASA Technical Reports Server (NTRS)

    Chamberlain, R. G.

    1979-01-01

    An extensive research and development activity to reduce the cost of manufacturing photovoltaic solar arrays by a factor of approximately one hundred is discussed. Proposed and actual manufacturing process descriptions were compared to manufacturing costs. An overview of this methodology is presented.

  3. Daytime Solar Heating of Photovoltaic Arrays in Low Density Plasmas

    NASA Technical Reports Server (NTRS)

    Galofaro, J.; Vayner, B.; Ferguson, D.

    2003-01-01

    The purpose of the current work is to determine the out-gassing rate of H2O molecules for a solar array placed under daytime solar heating (full sunlight) conditions typically encountered in a Low Earth Orbital (LEO) environment. Arc rates are established for individual arrays held at 14 C and are used as a baseline for future comparisons. Radiated thermal solar flux incident to the array is simulated by mounting a stainless steel panel equipped with resistive heating elements several centimeters behind the array. A thermal plot of the heater plate temperature and the array temperature as a function of heating time is then obtained. A mass spectrometer is used to record the levels of partial pressure of water vapor in the test chamber after each of the 5 heating/cooling cycles. Each of the heating cycles was set to time duration of 40 minutes to simulate the daytime solar heat flux to the array over a single orbit. Finally the array is cooled back to ambient temperature after 5 complete cycles and the arc rates of the solar arrays is retested. A comparison of the various data is presented with rather some unexpected results.

  4. Wind loads on flat plate photovoltaic array fields. Phase III, final report

    SciTech Connect

    Miller, R.D.; Zimmerman, D.K.

    1981-04-01

    The results of an experimental analysis (boundary layer wind tunnel test) of the aerodynamic forces resulting from winds acting on flat plate photovoltaic arrays are presented. Local pressure coefficient distributions and normal force coefficients on the arrays are shown and compared to theoretical results. Parameters that were varied when determining the aerodynamic forces included tilt angle, array separation, ground clearance, protective wind barriers, and the effect of the wind velocity profile. Recommended design wind forces and pressures are presented, which envelop the test results for winds perpendicular to the array's longitudinal axis. This wind direction produces the maximum wind loads on the arrays except at the array edge where oblique winds produce larger edge pressure loads.

  5. Dense nanoimprinted silicon nanowire arrays with passivated axial p-i-n junctions for photovoltaic applications

    SciTech Connect

    Zhang, Peng; Liu, Pei; Siontas, Stylianos; Zaslavsky, A.; Pacifici, D.; Ha, Jong-Yoon; Krylyuk, S.; Davydov, A. V.

    2015-03-28

    We report on the fabrication and photovoltaic characteristics of vertical arrays of silicon axial p-i-n junction nanowire (NW) solar cells grown by vapor-liquid-solid (VLS) epitaxy. NW surface passivation with silicon dioxide shell is shown to enhance carrier recombination time, open-circuit voltage (V{sub OC}), short-circuit current density (J{sub SC}), and fill factor (FF). The photovoltaic performance of passivated individual NW and NW arrays was compared under 532 nm laser illumination with power density of ∼10 W/cm{sup 2}. Higher values of V{sub OC} and FF in the NW arrays are explained by enhanced light trapping. In order to verify the effect of NW density on light absorption and hence on the photovoltaic performance of NW arrays, dense Si NW arrays were fabricated using nanoimprint lithography to periodically arrange the gold seed particles prior to epitaxial growth. Compared to sparse NW arrays fabricated using VLS growth from randomly distributed gold seeds, the nanoimprinted NW array solar cells show a greatly increased peak external quantum efficiency of ∼8% and internal quantum efficiency of ∼90% in the visible spectral range. Three-dimensional finite-difference time-domain simulations of Si NW periodic arrays with varying pitch (P) confirm the importance of high NW density. Specifically, due to diffractive scattering and light trapping, absorption efficiency close to 100% in the 400–650 nm spectral range is calculated for a Si NW array with P = 250 nm, significantly outperforming a blanket Si film of the same thickness.

  6. Development of a building block design of modular photovoltaic concentrator array fields

    SciTech Connect

    Carmichael, D.C.; Alexander, G.; Noel, G.T.; Scurlock, L.D.; Huss, W.R.; Stickford, G.H.

    1983-08-01

    To reduce the balance-of-system (BOS) costs and site-specific design costs for photovoltaic concentrator array fields, a modular Building Block design has been developed for installing array fields of each of two available concentrator collectors. The array-field subsystems and requirements incorporated in the design analyses include site preparation, foundations, electrical wiring, grounding, lightning protection, electromagnetic interference provisions, and tracking and controls. The Building Block designs developed minimize these array-field BOS costs and serve as standardized units to be used in multiples to construct array fields of various sizes. The detailed drawings and construction specifications prepared for the designs require only minimal design modification and cost for adaption to a specific site and application. The two concentrator collectors for which the modular array-field designs were developed are the linear-focus Fresnel-lens array manufactured by E-Systems, Inc., and the point-focus Fresnel-lens array manufactured by Martin Marietta Aerospace Corporation. Both designs are two-axis tracking and passively cooled. The developed Building Block designs are immediately applicable and reduce the array-field BOS costs and site-specific design costs to a fraction of those experienced in previous installations. The estimated array-field BOS costs (in 1982 dollars) using these modular designs are $0.78/W for the modular field based on the E-Systems array and $1.18/W for the modular field based on the Martin-Marietta array.

  7. Data base on batteries, power-conditioning equipment, and photovoltaic arrays. Final report

    SciTech Connect

    Podder, A; Kapner, M; Morse, T

    1981-02-01

    The objective of this study was to compile an up-to-date comprehensive data base for research, design, and development of photovoltaic systems, primarily in the areas of applications and battery technology, and secondarily in the area of power conditioning and photovoltaic array technology. This volume contains the data base used to develop the end-use scenarios and identify the R and D needed for batteries to be used in photovoltaic power systems. In addition to its specific application to the present study, this data base is intended to provide state-of-the-art information to manufacturers of the various components of photovoltaic power systems, system designers, and researchers in this field. An extensive literature search was conducted to obtain technical data on batteries, power conditioners, and photovoltaic arrays. The data obtained from published technical literature and direct communication with manufacturers and developers are compiled. Principles of operation, types of systems, performance characteristics, test data, and cost data are included for each of the components. (WHK)

  8. The Stretched Lens Array (SLA): An Ultra-Light Photovoltaic Concentrator

    NASA Astrophysics Data System (ADS)

    ONeill, Mark J.; Pisczor, Michael F.; Eskenazi, Michael I.; McDanal, A. J.; George, Patrick J.; Botke, Matthew M.; Brandhorst, Henry W.; Edwards, David L.; Jaster, Paul A.

    2002-10-01

    A high-performance, ultralight, photovoltaic concentrator array is being developed for space power. The stretched lens array (SLA) uses stretched-membrane, silicone Fresnel lenses to concentrate sunlight onto triple-junction photovoltaic cells. The cells are mounted to a composite radiator structure. The entire solar array wing, including lenses, photovoltaic cell flex circuits, composite panels, hinges, yoke, wiring harness, and deployment mechanisms, has a mass density of 1.6 kg/sq.m. NASA Glenn has measured 27.4% net SLA panel efficiency, or 375 W/sq.m. power density, at room temperature. At GEO operating cell temperature (80 C), this power density will be 300 W/sq.m., resulting in more than 180 W/kg specific power at the full wing level. SLA is a direct ultralight descendent of the successful SCARLET array on NASA's Deep Space 1 spacecraft. This paper describes the evolution from SCARLET to SLA, summarizes the SLA's key features, and provides performance and mass data for this new concentrator array.

  9. The Stretched Lens Array (SLA): An Ultra-Light Photovoltaic Concentrator

    NASA Technical Reports Server (NTRS)

    ONeill, Mark J.; Pisczor, Michael F.; Eskenazi, Michael I.; McDanal, A. J.; George, Patrick J.; Botke, Matthew M.; Brandhorst, Henry W.; Edwards, David L.; Jaster, Paul A.

    2002-01-01

    A high-performance, ultralight, photovoltaic concentrator array is being developed for space power. The stretched lens array (SLA) uses stretched-membrane, silicone Fresnel lenses to concentrate sunlight onto triple-junction photovoltaic cells. The cells are mounted to a composite radiator structure. The entire solar array wing, including lenses, photovoltaic cell flex circuits, composite panels, hinges, yoke, wiring harness, and deployment mechanisms, has a mass density of 1.6 kg/sq.m. NASA Glenn has measured 27.4% net SLA panel efficiency, or 375 W/sq.m. power density, at room temperature. At GEO operating cell temperature (80 C), this power density will be 300 W/sq.m., resulting in more than 180 W/kg specific power at the full wing level. SLA is a direct ultralight descendent of the successful SCARLET array on NASA's Deep Space 1 spacecraft. This paper describes the evolution from SCARLET to SLA, summarizes the SLA's key features, and provides performance and mass data for this new concentrator array.

  10. Performance degradation mechanisms and modes in terrestrial photovoltaic arrays and technology for their diagnosis

    NASA Technical Reports Server (NTRS)

    Noel, G. T.; Sliemers, F. A.; Derringer, G. C.; Wood, V. E.; Wilkes, K. E.; Gaines, G. B.; Carmichael, D. C.

    1978-01-01

    Accelerated life-prediction test methodologies have been developed for the validation of a 20-year service life for low-cost photovoltaic arrays. Array failure modes, relevant materials property changes, and primary degradation mechanisms are discussed as a prerequisite to identifying suitable measurement techniques and instruments. Measurements must provide sufficient confidence to permit selection among alternative designs and materials and to stimulate widespread deployment of such arrays. Furthermore, the diversity of candidate materials and designs, and the variety of potential environmental stress combinations, degradation mechanisms and failure modes require that combinations of measurement techniques be identified which are suitable for the characterization of various encapsulation system-cell structure-environment combinations.

  11. Solar Powered Aircraft, Photovoltaic Array/Battery System Tabletop Demonstration: Design and Operation Manual

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Scheiman, David A.; Bailey, Sheila (Technical Monitor)

    2000-01-01

    A system was constructed to demonstrate the power system operation of a solar powered aircraft. The system consists of a photovoltaic (PV) array, a charge controller, a battery, an electric motor and propeller. The system collects energy from the PV array and either utilizes this energy to operate an electric motor or stores it in a rechargeable battery for future use. The system has a control panel which displays the output of the array and battery as well as the total current going to the electric motor. The control panel also has a means for adjusting the output to the motor to control its speed. The entire system is regulated around 12 VDC.

  12. Advanced thermal management materials for concentrator photovoltaic arrays

    NASA Astrophysics Data System (ADS)

    Zweben, Carl

    2010-08-01

    Thermal management is a critical issue for photovoltaics (PVs), especially concentrator photovoltaic systems. Thermal management problems are similar for all semiconductors, including those used in microelectronics and other optoelectronic applications, such as lasers, light-emitting diodes (LEDs), detectors and displays. We divide the thermal management problem into two parts: heat dissipation and thermal stresses. Heat dissipation affects efficiency and lifetime. Thermal stresses affect manufacturing yield and lifetime. Traditional thermal management materials all have serious deficiencies. Copper and aluminum have high coefficients of thermal expansion (CTEs), which can cause severe thermal stresses during manufacturing and in service. Compliant attach materials, used to minimize thermal stresses, all have major drawbacks. Traditional low-CTE thermal management materials have relatively low thermal conductivities and are hard to machine. In response to these deficiencies, new thermal management materials have been, and are continuing to be developed, which have low CTEs and thermal conductivities up to four times that of copper. Some are reportedly are cheaper than copper. In this paper, we survey the six categories of advanced thermal materials, including properties, state of maturity and cost. We also review a CPV application in which an advanced metal matrix composite with a tailored CTE eliminated solder joint failure and provided other benefits.

  13. Dark Forward Electrical Test Techniques Developed for Large-Area Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    Kerslake, Thomas W.; Scheiman, David A.; Hoffman, David J.

    1998-01-01

    Spacecraft photovoltaic arrays (PVA's) must be carefully handled during ground integration processing and transportation to the launch site. Care is exercised to avoid damage that could degrade on-orbit electrical performance. Because of this damage risk, however, PVA's are typically deployed and illuminated with a light source so performance characteristics can be measured prior to launch. For large-area arrays, such as the Mir Cooperative Solar Array (2.7- by 18-m) and the International Space Station PVA blankets (4.6- by 31.7-m), this integrity check becomes resource intensive. Large test support structures are needed to offload the array during deployment in 1g, and large-aperture illumination equipment is required to uniformly illuminate array panels. Significant program time, funds, and manpower must be allocated for this kind of test program. Alternatively, launch site electrical performance tests can be bypassed with an attendant increase in risk.

  14. Optimized design and research of secondary microprism for dense array concentrating photovoltaic module

    NASA Astrophysics Data System (ADS)

    Yang, Guanghui; Chen, Bingzhen; Liu, Youqiang; Guo, Limin; Yao, Shun; Wang, Zhiyong

    2015-10-01

    As the critical component of concentrating photovoltaic module, secondary concentrators can be effective in increasing the acceptance angle and incident light, as well as improving the energy uniformity of focal spots. This paper presents a design of transmission-type secondary microprism for dense array concentrating photovoltaic module. The 3-D model of this design is established by Solidworks and important parameters such as inclination angle and component height are optimized using Zemax. According to the design and simulation results, several secondary microprisms with different parameters are fabricated and tested in combination with Fresnel lens and multi-junction solar cell. The sun-simulator IV test results show that the combination has the highest output power when secondary microprism height is 5mm and top facet side length is 7mm. Compared with the case without secondary microprism, the output power can improve 11% after the employment of secondary microprisms, indicating the indispensability of secondary microprisms in concentrating photovoltaic module.

  15. Proceedings of the flat-plate solar array project research forum on photovoltaic metallization systems

    SciTech Connect

    1983-11-15

    A Photovoltaic Metallization Research Forum, under the sponsorship of the Jet Propulsion Laboratory's Flat-Plate Solar Array Project and the US Department of Energy, was held March 16-18, 1983 at Pine Mountain, Georgia. The Forum consisted of five sessions, covering (1) the current status of metallization systems, (2) system design, (3) thick-film metallization, (4) advanced techniques and (5) future metallization challenges. Twenty-three papers were presented.

  16. Space satellite power system. [conversion of solar energy by photovoltaic solar cell arrays

    NASA Technical Reports Server (NTRS)

    Glaser, P. E.

    1974-01-01

    The concept of a satellite solar power station was studied. It is shown that it offers the potential to meet a significant portion of future energy needs, is pollution free, and is sparing of irreplaceable earth resources. Solar energy is converted by photovoltaic solar cell arrays to dc energy which in turn is converted into microwave energy in a large active phased array. The microwave energy is beamed to earth with little attenuation and is converted back to dc energy on the earth. Economic factors are considered.

  17. Formation of Ge quantum dots array in layer-cake technique for advanced photovoltaics

    NASA Astrophysics Data System (ADS)

    Chien, C. Y.; Chang, Y. J.; Chang, J. E.; Lee, M. S.; Chen, W. Y.; Hsu, T. M.; Li, P. W.

    2010-12-01

    We report a simple and manageable growth method for placing dense three-dimensional Ge quantum dot (QD) arrays in a uniform or a graded size distribution, based on thermally oxidizing stacked poly-SiGe in a layer-cake technique. The QD size and spatial density in each stack can be modulated by conditions of the Ge content in poly-Si1 - xGex, oxidation, and the underlay buffer layer. Size-dependent internal structure, strain, and photoluminescence properties of Ge QDs are systematically investigated. Optimization of the processing conditions could be carried out for producing dense Ge QD arrays to maximize photovoltaic efficiency.

  18. Formation of organic crystalline nanopillar arrays and their application to organic photovoltaic cells.

    PubMed

    Hirade, Masaya; Nakanotani, Hajime; Yahiro, Masayuki; Adachi, Chihaya

    2011-01-01

    To enhance the performance of organic photovoltaic (OPV) cells, preparation of organic nanometer-sized pillar arrays is fascinating because a significantly large area of a donor/acceptor heterointerface having continuous conduction path to both anode and cathode electrodes can be realized. In this study, we grew cupper phthalocyanine (CuPc) crystalline nanopillar arrays by conventional thermal gradient sublimation technique using a few-nanometer-sized trigger seeds composed of a CuPc and 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) stacked layer. We optimized the pillar density by tuning crystal growth condition in order to apply it to OPV cells.

  19. Si Radial p-i-n Junction Photovoltaic Arrays with Built-In Light Concentrators.

    PubMed

    Yoo, Jinkyoung; Nguyen, Binh-Minh; Campbell, Ian H; Dayeh, Shadi A; Schuele, Paul; Evans, David; Picraux, S Tom

    2015-05-26

    High-performance photovoltaic (PV) devices require strong light absorption, low reflection and efficient photogenerated carrier collection for high quantum efficiency. Previous optical studies of vertical wires arrays have revealed that extremely efficient light absorption in the visible wavelengths is achievable. Photovoltaic studies have further advanced the wire approach by employing radial p-n junction architectures to achieve more efficient carrier collection. While radial p-n junction formation and optimized light absorption have independently been considered, PV efficiencies have further opportunities for enhancement by exploiting the radial p-n junction fabrication procedures to form arrays that simultaneously enhance both light absorption and carrier collection efficiency. Here we report a concept of morphology control to improve PV performance, light absorption and quantum efficiency of silicon radial p-i-n junction arrays. Surface energy minimization during vapor phase epitaxy is exploited to form match-head structures at the tips of the wires. The match-head structure acts as a built-in light concentrator and enhances optical absorptance and external quantum efficiencies by 30 to 40%, and PV efficiency under AM 1.5G illumination by 20% compared to cylindrical structures without match-heads. The design rules for these improvements with match-head arrays are systematically studied. This approach of process-enhanced control of three-dimensional Si morphologies provides a fab-compatible way to enhance the PV performance of Si radial p-n junction wire arrays. PMID:25961330

  20. Si Radial p-i-n Junction Photovoltaic Arrays with Built-In Light Concentrators.

    PubMed

    Yoo, Jinkyoung; Nguyen, Binh-Minh; Campbell, Ian H; Dayeh, Shadi A; Schuele, Paul; Evans, David; Picraux, S Tom

    2015-05-26

    High-performance photovoltaic (PV) devices require strong light absorption, low reflection and efficient photogenerated carrier collection for high quantum efficiency. Previous optical studies of vertical wires arrays have revealed that extremely efficient light absorption in the visible wavelengths is achievable. Photovoltaic studies have further advanced the wire approach by employing radial p-n junction architectures to achieve more efficient carrier collection. While radial p-n junction formation and optimized light absorption have independently been considered, PV efficiencies have further opportunities for enhancement by exploiting the radial p-n junction fabrication procedures to form arrays that simultaneously enhance both light absorption and carrier collection efficiency. Here we report a concept of morphology control to improve PV performance, light absorption and quantum efficiency of silicon radial p-i-n junction arrays. Surface energy minimization during vapor phase epitaxy is exploited to form match-head structures at the tips of the wires. The match-head structure acts as a built-in light concentrator and enhances optical absorptance and external quantum efficiencies by 30 to 40%, and PV efficiency under AM 1.5G illumination by 20% compared to cylindrical structures without match-heads. The design rules for these improvements with match-head arrays are systematically studied. This approach of process-enhanced control of three-dimensional Si morphologies provides a fab-compatible way to enhance the PV performance of Si radial p-n junction wire arrays.

  1. Analysis of mismatch and shading effects in a photovoltaic array using different technologies

    NASA Astrophysics Data System (ADS)

    Guerrero, J.; Muñoz, Y.; Ibáñez, F.; Ospino, A.

    2014-06-01

    In this paper, we analyze the performance of a photovoltaic array implemented in the Universidad Politécnica de Valencia which consists of modules of different technologies and power, connected in series, in order to quantify the energy losses due to mismatch and the effect of the shadows. To do this, the performance of the modules was measured in operation under ambient conditions with field measurement equipment (AMPROBE Solar Analyzer, Solar - 4000), which allows the extrapolation of measures to standard conditions STC. For the data validation, measures under controlled conditions were taken to some modules in the flash test laboratory of the Institute of Energy Technology ITE of Valencia in Spain. Subsequently the array curves measured were validated with a photovoltaic array model developed in MATLAB-Simulink for the same conditions and technologies. The results of this particular array are lost up to 20% of the energy supplied due to the modules mismatch. The study shows the curves and the energy loss due to shadows modules. This result opens scenarios for conceivable modifications to the PV field configurations today, chosen during the design stage and unchangeable during the operating stage; and gives greater importance to the energy loss by mismatch in the PV array.

  2. Control of zinc oxide nanowire array properties with electron-beam lithography templating for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Nicaise, Samuel M.; Cheng, Jayce J.; Kiani, Amirreza; Gradečak, Silvija; Berggren, Karl K.

    2015-02-01

    Hydrothermally synthesized zinc oxide nanowire arrays have been used as nanostructured acceptors in emerging photovoltaic (PV) devices. The nanoscale dimensions of such arrays allow for enhanced charge extraction from PV active layers, but the device performance critically depends on the nanowire array pitch and alignment. In this study, we templated hydrothermally-grown ZnO nanowire arrays via high-resolution electron-beam-lithography defined masks, achieving the dual requirements of high-resolution patterning at a pitch of several hundred nanometers, while maintaining hole sizes small enough to control nanowire array morphology. We investigated several process conditions, including the effect of annealing sputtered and spincoated ZnO seed layers on nanowire growth, to optimize array property metrics—branching from individual template holes and off-normal alignment. We found that decreasing template hole size decreased branching prevalence but also reduced alignment. Annealing seed layers typically improved alignment, and sputtered seed layers yielded nanowire arrays superior to spincoated seed layers. We show that these effects arose from variation in the size of the template holes relative to the ZnO grain size in the seed layer. The quantitative control of branching and alignment of the nanowire array that is achieved in this study will open new paths toward engineering more efficient electrodes to increase photocurrent in nanostructured PVs. This control is also applicable to inorganic nanowire growth in general, nanomechanical generators, nanowire transistors, and surface-energy engineering.

  3. Crystal Orientation Controlled Photovoltaic Properties of Multilayer GaAs Nanowire Arrays.

    PubMed

    Han, Ning; Yang, Zai-Xing; Wang, Fengyun; Yip, SenPo; Li, Dapan; Hung, Tak Fu; Chen, Yunfa; Ho, Johnny C

    2016-06-28

    In recent years, despite significant progress in the synthesis, characterization, and integration of various nanowire (NW) material systems, crystal orientation controlled NW growth as well as real-time assessment of their growth-structure-property relationships still presents one of the major challenges in deploying NWs for practical large-scale applications. In this study, we propose, design, and develop a multilayer NW printing scheme for the determination of crystal orientation controlled photovoltaic properties of parallel GaAs NW arrays. By tuning the catalyst thickness and nucleation and growth temperatures in the two-step chemical vapor deposition, crystalline GaAs NWs with uniform, pure ⟨110⟩ and ⟨111⟩ orientations and other mixture ratios can be successfully prepared. Employing lift-off resists, three-layer NW parallel arrays can be easily attained for X-ray diffraction in order to evaluate their growth orientation along with the fabrication of NW parallel array based Schottky photovoltaic devices for the subsequent performance assessment. Notably, the open-circuit voltage of purely ⟨111⟩-oriented NW arrayed cells is far higher than that of ⟨110⟩-oriented NW arrayed counterparts, which can be interpreted by the different surface Fermi level pinning that exists on various NW crystal surface planes due to the different As dangling bond densities. All this indicates the profound effect of NW crystal orientation on physical and chemical properties of GaAs NWs, suggesting the careful NW design considerations for achieving optimal photovoltaic performances. The approach presented here could also serve as a versatile and powerful platform for in situ characterization of other NW materials. PMID:27223050

  4. Crystal Orientation Controlled Photovoltaic Properties of Multilayer GaAs Nanowire Arrays.

    PubMed

    Han, Ning; Yang, Zai-Xing; Wang, Fengyun; Yip, SenPo; Li, Dapan; Hung, Tak Fu; Chen, Yunfa; Ho, Johnny C

    2016-06-28

    In recent years, despite significant progress in the synthesis, characterization, and integration of various nanowire (NW) material systems, crystal orientation controlled NW growth as well as real-time assessment of their growth-structure-property relationships still presents one of the major challenges in deploying NWs for practical large-scale applications. In this study, we propose, design, and develop a multilayer NW printing scheme for the determination of crystal orientation controlled photovoltaic properties of parallel GaAs NW arrays. By tuning the catalyst thickness and nucleation and growth temperatures in the two-step chemical vapor deposition, crystalline GaAs NWs with uniform, pure ⟨110⟩ and ⟨111⟩ orientations and other mixture ratios can be successfully prepared. Employing lift-off resists, three-layer NW parallel arrays can be easily attained for X-ray diffraction in order to evaluate their growth orientation along with the fabrication of NW parallel array based Schottky photovoltaic devices for the subsequent performance assessment. Notably, the open-circuit voltage of purely ⟨111⟩-oriented NW arrayed cells is far higher than that of ⟨110⟩-oriented NW arrayed counterparts, which can be interpreted by the different surface Fermi level pinning that exists on various NW crystal surface planes due to the different As dangling bond densities. All this indicates the profound effect of NW crystal orientation on physical and chemical properties of GaAs NWs, suggesting the careful NW design considerations for achieving optimal photovoltaic performances. The approach presented here could also serve as a versatile and powerful platform for in situ characterization of other NW materials.

  5. Engineering study of the module/array interface for large terrestrial photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Three major areas--structural, electrical, and maintenance--were evaluated. Efforts in the structural area included establishing acceptance criteria for materials and members, determining loading criteria, and analyzing glass modules in various framing system configurations. Array support structure design was addressed briefly. Electrical considerations included evaluation of module characteristics, intermodule connectors, array wiring, converters and lightning protection. Plant maintenance features such as array cleaning, failure detection, and module installation and replacement were addressed.

  6. Unlikely Combination of Experiments With a Novel High-Voltage CIGS Photovoltaic Array: Preprint

    SciTech Connect

    del Cueto, J. A.; Sekulic, B. R.

    2006-05-01

    A new high-voltage array comprising bipolar strings of copper indium gallium diselenide (CIGS) photovoltaic (PV) modules was inaugurated in 2005. It is equipped with a unique combination of tests, which likely have never before been deployed simultaneously within a single array: full current-voltage (I-V) traces, high-voltage leakage current measurements, and peak-power tracking or temporal stepped-bias profiling. The array nominally produces 1 kW power at 1 sun. The array's electrical characteristics are continuously monitored and controlled with a programmable electronic load interfaced to a data acquisition system (DAS), that also records solar and meteorological data. The modules are mounted with their frames electrically isolated from earth ground, in order to facilitate measurement of the leakage currents that arise between the high voltage bias developed in the series-connected cells and modules and their mounting frames. Because the DAS can perform stepped biasing of the array as a function of time, synchronous detection of the leakage current data with alternating bias is available. Leakage current data and their dependence on temperature and voltage are investigated. Array power data are analyzed across a wide range of varying illuminations and temperatures from the I-V traces. Array performance is also analyzed from an energy output perspective using peak-power tracking data.

  7. Modeling and reconfiguration of solar photovoltaic arrays under non-uniform shadow conditions

    NASA Astrophysics Data System (ADS)

    Nguyen, Dung Duc

    Mass production and use of electricity generated from solar energy has become very common recently because of the environmental threats arising from the production of electricity from fossil fuels and nuclear power. The obvious benefits of solar energy are clean energy production and infinite supply of daylight. The main disadvantage is the high cost. In these photovoltaic systems, semiconductor materials convert the solar light into electrical energy. Current versus voltage characteristics of the solar cells are nonlinear, thus leading to technical control challenges. In the first order approximation, output power of a solar array is proportional to the irradiance of sunlight. However, in many applications, such as solar power plants, building integrated photovoltaic or solar tents, the solar photovoltaic arrays might be illuminated non-uniformly. The cause of non-uniform illumination may be the shadow of clouds, the trees, booms, neighbor's houses, or the shadow of one solar array on the other, etc. This further leads to nonlinearities in characteristics. Because of the nature of the electrical characteristics of solar cells, the maximum power losses are not proportional to the shadow, but magnify nonlinearly [1]. Further, shadows of solar PV array can cause other undesired effects: (1) The power actually generated from the solar PV array is much less than designed. At some systems, the annual losses because of the shadow effects can be reached 10%. Thus, the probability for "loss of load" increases [2]. (2) The local hot spot in the shaded part of the solar PV array can damage the solar cells. The shaded solar cells may be work on the negative voltage region and become a resistive load and absorb power. Bypass diodes are sometimes connected parallel to solar cells to protect them from damage. However, in most cases, just one diode is connected in parallel to group of solar cells [3], and this hidden the potential power output of the array. This proposed research

  8. Ground testing of array modules for the photovoltaic array space power (PASP) experiment

    NASA Technical Reports Server (NTRS)

    Morris, Robert K.; Grier, Norman T.

    1987-01-01

    One of the objectives of the PASP experiment is the verification of cost-effective ground simulations of high-voltage solar array/space-environment interactions by comparing the results with flight data. These ground tests consist of electrical characterization, thermal cycling, and plasma chamber simulations. The results of the latter tests are reported. Five array modules which are representative of the flight arrays were tested. The module types are planar silicon, planar gallium arsenide, planar silicon passivated with an integrally deposited cover glass, mini-Cassegrainian concentrator, and SLATS concentrator. The modules were biased to -1000 V in varying plasma densities from 4 x 103 to 2 x 105 e-/cu cm. Each array was tested in both dark and illuminated conditions with a load resistance. In addition to monitoring arcing during the plasma tests, the arrays were visually inspected and electrically characterized before and after exposure in the chamber. The electrical results are tabulated and briefly discussed.

  9. Space Photovoltaic Research and Technology, 1988. High Efficiency, Space Environment, and Array Technology

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The 9th Space Photovoltaic Research and Technology conference was held at the NASA Lewis Research Center from April 19 to 21, 1988. The papers and workshop summaries report remarkable progress on a wide variety of approaches in space photovoltaics, for both near and far term applications. Among the former is the recently developed high efficiency GaAs/Ge cell, which formed the focus of a workshop discussion on heteroepitaxial cells. Still aimed at the long term, but with a significant payoff in a new mission capability, are InP cells, with their potentially dramatic improvement in radiation resistance. Approaches to near term, array specific powers exceeding 130 W/kg are also reported, and advanced concentrator panel technology with the potential to achieve over 250 W/sq m is beginning to take shape.

  10. A systematic method of interconnection optimization for dense-array concentrator photovoltaic system.

    PubMed

    Siaw, Fei-Lu; Chong, Kok-Keong

    2013-01-01

    This paper presents a new systematic approach to analyze all possible array configurations in order to determine the most optimal dense-array configuration for concentrator photovoltaic (CPV) systems. The proposed method is fast, simple, reasonably accurate, and very useful as a preliminary study before constructing a dense-array CPV panel. Using measured flux distribution data, each CPV cells' voltage and current values at three critical points which are at short-circuit, open-circuit, and maximum power point are determined. From there, an algorithm groups the cells into basic modules. The next step is I-V curve prediction, to find the maximum output power of each array configuration. As a case study, twenty different I-V predictions are made for a prototype of nonimaging planar concentrator, and the array configuration that yields the highest output power is determined. The result is then verified by assembling and testing of an actual dense-array on the prototype. It was found that the I-V curve closely resembles simulated I-V prediction, and measured maximum output power varies by only 1.34%.

  11. A Systematic Method of Interconnection Optimization for Dense-Array Concentrator Photovoltaic System

    PubMed Central

    Siaw, Fei-Lu

    2013-01-01

    This paper presents a new systematic approach to analyze all possible array configurations in order to determine the most optimal dense-array configuration for concentrator photovoltaic (CPV) systems. The proposed method is fast, simple, reasonably accurate, and very useful as a preliminary study before constructing a dense-array CPV panel. Using measured flux distribution data, each CPV cells' voltage and current values at three critical points which are at short-circuit, open-circuit, and maximum power point are determined. From there, an algorithm groups the cells into basic modules. The next step is I-V curve prediction, to find the maximum output power of each array configuration. As a case study, twenty different I-V predictions are made for a prototype of nonimaging planar concentrator, and the array configuration that yields the highest output power is determined. The result is then verified by assembling and testing of an actual dense-array on the prototype. It was found that the I-V curve closely resembles simulated I-V prediction, and measured maximum output power varies by only 1.34%. PMID:24453823

  12. A systematic method of interconnection optimization for dense-array concentrator photovoltaic system.

    PubMed

    Siaw, Fei-Lu; Chong, Kok-Keong

    2013-01-01

    This paper presents a new systematic approach to analyze all possible array configurations in order to determine the most optimal dense-array configuration for concentrator photovoltaic (CPV) systems. The proposed method is fast, simple, reasonably accurate, and very useful as a preliminary study before constructing a dense-array CPV panel. Using measured flux distribution data, each CPV cells' voltage and current values at three critical points which are at short-circuit, open-circuit, and maximum power point are determined. From there, an algorithm groups the cells into basic modules. The next step is I-V curve prediction, to find the maximum output power of each array configuration. As a case study, twenty different I-V predictions are made for a prototype of nonimaging planar concentrator, and the array configuration that yields the highest output power is determined. The result is then verified by assembling and testing of an actual dense-array on the prototype. It was found that the I-V curve closely resembles simulated I-V prediction, and measured maximum output power varies by only 1.34%. PMID:24453823

  13. Atomic oxygen durability evaluation of the flexible batten for the photovoltaic array mast on Space Station

    NASA Technical Reports Server (NTRS)

    Stidham, Curtis R.; Rutledge, Sharon K.; Sechkar, Edward A.; Flaherty, David S.; Roig, David M.; Edwards, Jonathan L.

    1994-01-01

    A test program was conducted at the National Aeronautics and Space Administration's Lewis Research Center (LeRC) to evaluate the long term low Earth orbital (LEO) atomic oxygen (AO) durability of a flexible (fiberglass-epoxy composite) batten. The flexible batten is a component used to provide structural rigidity in the photovoltaic array mast on Space Station. The mast is used to support and articulate the photovoltaic array, therefore, the flexible batten must be preloaded for the 15 year lifetime of an array blanket. Development hardware and composite materials were evaluated in ground testing facilities for AO durability and dynamic retraction-deployment cyclic loading representative of expected full life in-space application. The CV1144 silicone (AO protective) coating was determined to provide adequate protection against AO degradation of the composite material and provided fiber containment, thus the structural integrity of the flexible batten was maintained. Both silicone coated and uncoated flexible battens maintained load carrying capabilities. Results of the testing did indicate that the CV1144 silicone protective coating was oxidized by AO reactions to form a brittle glassy (SiO2) skin that formed cracking patterns on all sides of the coated samples. The cracking was observed in samples that were mechanically stressed as well as samples in non-stressed conditions. The oxidized silicon was observed to randomly spall in small localized areas, on the flexible battens that underwent retraction-deployment cycling. Some darkening of the silicon, attributed to vacuum ultraviolet (VUV) radiation, was observed.

  14. On-Orbit Electrical Performance of a Mir Space Station Photovoltaic Array Predicted

    NASA Technical Reports Server (NTRS)

    Kerslake, Thomas W.; Hoffman, David J.; Hojnicki, Jeffrey S.

    1998-01-01

    The Mir Cooperative Solar Array (MCSA) was developed jointly by the United States and Russia to provide approximately 6 kW of photovoltaic power to the Russian space station Mir. The MCSA was launched to Mir in November 1995 and installed on the Kvant-1 module in May 1996, where it has been performing well to date. Since the MCSA panels are nearly identical to those of the International Space Station (ISS), MCSA operation offered an opportunity to gather multiyear performance data on this technology prior to its implementation on the ISS. Initial, on-orbit electrical performance and temperature data were measured in June and December of 1996.

  15. Electricity from photovoltaic solar cells. Flat-Plate Solar Array Project of the US Department of Energy's National Photovoltaics Program: 10 years of progress

    NASA Technical Reports Server (NTRS)

    Christensen, Elmer

    1985-01-01

    The objectives were to develop the flat-plate photovoltaic (PV) array technologies required for large-scale terrestrial use late in the 1980s and in the 1990s; advance crystalline silicon PV technologies; develop the technologies required to convert thin-film PV research results into viable module and array technology; and to stimulate transfer of knowledge of advanced PV materials, solar cells, modules, and arrays to the PV community. Progress reached on attaining these goals, along with future recommendations are discussed.

  16. High efficiency, broadband solar cell architectures based on arrays of volumetrically distributed narrowband photovoltaic fibers.

    PubMed

    O'Connor, Brendan; Nothern, Denis; Pipe, Kevin P; Shtein, Max

    2010-09-13

    We propose a novel solar cell architecture consisting of multiple fiber-based photovoltaic (PV) cells. Each PV fiber element is designed to maximize the power conversion efficiency within a narrow band of the incident solar spectrum, while reflecting other spectral components through the use of optical microcavity effects and distributed Bragg reflector (DBR) coatings. Combining PV fibers with complementary absorption and reflection characteristics into volume-filling arrays enables spectrally tuned modules having an effective dispersion element intrinsic to the architecture, resulting in high external quantum efficiency over the incident spectrum. While this new reflective tandem architecture is not limited to one particular material system, here we apply the concept to organic PV (OPV) cells that use a metal-organic-metal-dielectric layer structure, and calculate the expected performance of such arrays. Using realistic material properties for organic absorbers, transport layers, metallic electrodes, and DBR coatings, 17% power conversion efficiency can be reached.

  17. Measurement Techniques and Instruments Suitable for Life-prediction Testing of Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    Noel, G. T.; Wood, V. E.; Mcginniss, V. D.; Hassell, J. A.; Richard, N. A.; Gaines, G. B.; Carmichael, D. C.

    1979-01-01

    The validation of a 20-year service life for low-cost photovoltaic arrays is a critical requirement in the Low-Cost Solar Array (LSA) Project. The validation is accomplished through accelerated life-prediction tests. A two-phase study was conducted to address the needs before such tests are carried out. The results and recommended techniques from the Phase 1 investigation are summarized in the appendix. Phase 2 of the study is covered in this report and consisted of experimental evaluations of three techniques selected from these recommended as a results of the Phase 1 findings. The three techniques evaluated were specular and nonspecular optical reflectometry, chemiluminescence measurements, and electric current noise measurements.

  18. Review of world experience and properties of materials for encapsulation of terrestrial photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Carmichael, D. C.; Gaines, G. B.; Sliemers, F. A.; Kistler, C. W.; Igou, R. D.

    1976-01-01

    Published and unpublished information relating to encapsulation systems and materials properties was collected by searching the literature and appropriate data bases (over 1,300 documents were selected and reviewed) and by personal contacts including site and company visits. A data tabulation summarizing world experience with terrestrial photovoltaic arrays (50 installations) is presented in the report. Based on criteria of properties, processability, availability, and cost, candidate materials were identified which have potential for use in encapsulation systems for arrays with a lifetime of over 20 years high reliability, an efficiency greater than 10 percent, a total price less than $500/kW, and a production capacity of 500,000 kW/yr. The recommended materials (all commercially available) include, depending upon the device design, various borosilicate and soda-lime glasses and numerous polymerics suitable for specific encapsulation system functions.

  19. Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.; Phillips, Brandon S.

    2015-01-01

    CubeSats, Communication Satellites, and Outer Planet Science Satellites all share one thing in common: Mission success depends on maintaining power in the harsh space environment. For a vast majority of satellites, spacecraft power is sourced by a photovoltaic (PV) array system. Built around PV cells, the array systems also include wiring, substrates, connectors, and protection diodes. Each of these components must function properly throughout the mission in order for power production to remain at nominal levels. Failure of even one component can lead to a crippling loss of power. To help ensure PV array systems do not suffer failures on-orbit due to the space environment, NASA's Marshall Space Flight Center (MSFC) has developed a wide ranging test and evaluation capability. Key elements of this capability include: Testing: a. Ultraviolet (UV) Exposure b. Charged Particle Radiation (Electron and Proton) c. Thermal Cycling d. Plasma and Beam Environments Evaluation: a. Electrostatic Discharge (ESD) Screening b. Optical Inspection and easurement c. PV Power Output including Large Area Pulsed Solar Simulator (LAPSS) measurements This paper will describe the elements of the space environment which particularly impact PV array systems. MSFC test capabilities will be described to show how the relevant space environments can be applied to PV array systems in the laboratory. A discussion of MSFC evaluation capabilities will also be provided. The sample evaluation capabilities offer test engineers a means to quantify the effects of the space environment on their PV array system or component. Finally, examples will be shown of the effects of the space environment on actual PV array materials tested at MSFC.

  20. Portable, X-Y translating, infrared microscope for remote inspection of photovoltaic solar arrays

    SciTech Connect

    Forman, S.E.; Caunt, J.W.

    1980-01-01

    The prevalent physical defect found in terrestrial photovoltaic modules during manufacture and field exposure has been the cracked solar cell. Cells can become cracked during handling, because of thermal mismatch in their encapsulation packages, or due to environmental phenomena such as hail. A device is described which can be used remotely to locate cracked silicon solar cells in photovoltaic modules. This solar-cell inspection device can be used either in the laboratory for quality assurance and failure analysis evaluation or at array fields to monitor cracked-cell occurrence. It consists of: (a) an infrared microscope that operates at 1.0 micron, uses darkfield illumination, has a relatively large field of view (3.0 in.), has low system magnification (5X to 15X), and has a video display output; (b) a portable X-Y translator that is capable of moving the microscope over an 8 ft. x 8 ft. area; and (c) a console that allows remote instrument control and visual inspection of modules or arrays (up to 500 ft). This system presently is undergoing laboratory and field testing as part of the DOE-sponsored MIT Lincoln Laboratory Solar Photovoltiac Residential Project.

  1. Impact of LDEF photovoltaic experiment findings upon spacecraft solar array design and development requirements

    NASA Technical Reports Server (NTRS)

    Young, Leighton E.

    1993-01-01

    Photovoltaic cells (solar cells) and other solar array materials were flown in a variety of locations on the Long Duration Exposure Facility (LDEF). With respect to the predicted leading edge, solar array experiments were located at 0 degrees (row 9), 30 degrees (row 8) and 180 degrees (row 3). Postflight estimates of location of the experiments with respect to the velocity vector add 8.1 degrees to these values. Experiments were also located on the Earth end of the LDEF longitudinal axis. Types and magnitudes of detrimental effects differ between the locations with some commonality. Postflight evaluation of the solar array experiments reveal that some components/materials are very resistant to the environment to which they were exposed while others need protection, modification, or replacement. Interaction of materials with atomic oxygen (AO), as an area of major importance, was dramatically demonstrated by LDEF results. Information gained from the LDEF flight allows array developers to set new requirements for on-going and future technology and flight component development.

  2. Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Phillips, Brandon S.; Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.

    2015-01-01

    To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry (e.g. blocking diodes). Key elements of the space environment which must be accounted for in a PV system design include: Solar Photon Radiation, Charged Particle Radiation, Plasma, and Thermal Cycling. While solar photon radiation is central to generating power in PV systems, the complete spectrum includes short wavelength ultraviolet components, which photo-ionize materials, as well as long wavelength infrared which heat materials. High energy electron radiation has been demonstrated to significantly reduce the output power of III-V type PV cells; and proton radiation damages material surfaces - often impacting coverglasses and antireflective coatings. Plasma environments influence electrostatic charging of PV array materials, and must be understood to ensure that long duration arcs do not form and potentially destroy PV cells. Thermal cycling impacts all components on a PV array by inducing stresses due to thermal expansion and contraction. Given such demanding environments, and the complexity of structures and materials that form a PV array system, mission success can only be ensured through realistic testing in the laboratory. NASA's Marshall Space Flight Center has developed a broad space environment test capability to allow PV array designers and manufacturers to verify their system's integrity and avoid costly on-orbit failures. The Marshall Space Flight Center test capabilities are available to government, commercial, and university customers. Test solutions are tailored to meet the customer's needs, and can include performance assessments, such as flash testing in the case of PV cells.

  3. The status of lightweight photovoltaic space array technology based on amorphous silicon solar cells

    NASA Technical Reports Server (NTRS)

    Hanak, Joseph J.; Kaschmitter, Jim

    1991-01-01

    Ultralight, flexible photovoltaic (PV) array of amorphous silicon (a-Si) was identified as a potential low cost power source for small satellites. A survey was conducted of the status of the a-Si PV array technology with respect to present and future performance, availability, cost, and risks. For existing, experimental array blankets made of commercial cell material, utilizing metal foil substrates, the Beginning of Life (BOL) performance at Air Mass Zero (AM0) and 35 C includes total power up to 200 W, power per area of 64 W/sq m and power per weight of 258 W/kg. Doubling of power per weight occurs when polyimide substrates are used. Estimated End of Life (EOL) power output after 10 years in a nominal low earth orbit would be 80 pct. of BOL, the degradation being due to largely light induced effects (-10 to -15 pct.) and in part (-5 pct.) to space radiation. Predictions for the year 1995 for flexible PV arrays, made on the basis of published results for rigid a-Si modules, indicate EOL power output per area and per weight of 105 W/sq m and 400 W/kg, respectively, while predictions for the late 1990s based on existing U.S. national PV program goals indicate EOL values of 157 W/sq m and 600 W/kg. Cost estimates by vendors for 200 W ultralight arrays in volume of over 1000 units range from $100/watt to $125/watt. Identified risks include the lack of flexible, space compatible encapsulant, the lack of space qualification effort, recent partial or full acquisitions of US manufacturers of a-Si cells by foreign firms, and the absence of a national commitment for a long range development program toward developing of this important power source for space.

  4. Silicon nanowire arrays with passivated axial p-i-n junctions for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Liu, Pei; Zaslavsky, Alexander; Pacifici, Domenico; Ha, Jong-Yoon; Krylyuk, Sergiy; Davydov, Albert

    2014-03-01

    Metal catalyst-assisted vapor-liquid-solid mechanism can be used to grow large areas of nanowires (NWs) with compositional and doping control in either axial or core-shell geometries. Here, we report on vertical arrays of Si axial p- i- n oxide-passivated NWs that were 12 microns long with a 4 micron intrinsic section. The NW arrays were planarized using SU-8 photoresist, followed by reactive ion etching to expose the NW tips. Top n-contact was realized by sputter deposition of a 200 nm IZO layer. The p-contact was made by backside metallization of the p-Si substrate. Under AM 1.5 illumination, unpassivated NW arrays exhibited an open-circuit voltage, VOC of 170 mV, a short-circuit current density JSC >3.7 mA/cm2 (with uncertainty due to the unknown fraction of properly contacted NWs), and a fill factor of 28.9%. After the passivation, VOC, JSC and FF increased to 250 mV, >9.2 mA/cm2 and 35.7%, respectively. The measured normal reflectance was around 6% over the 400-1000 nm spectral range, whereas the diffuse reflectance was around 20% over the same range, indicating strong light scattering and absorption by the NWs. The photovoltaic performance of passivated single NWs and NW arrays were compared using a 532 nm laser with a power density of about 10 W/cm2. Higher values of VOC and FF obtained for the latter are explained by light trapping in the NW arrays.

  5. Low Earth orbit durability evaluation of protected silicone for advanced refractive photovoltaic concentrator arrays

    NASA Technical Reports Server (NTRS)

    Degroh, Kim K.; Mccollum, Timothy A.

    1994-01-01

    The need for efficient, cost effective sources of electrical power in space has led to the development of photovoltaic power systems which make use of novel refractive solar concentrators. These concentrators have been conceived in both point-focus and linear-focus designs. Current concentrator lenses are fabricated from flexible silicones with Fresnel facets along their inside surface. To insure the efficient operation of these power systems, the concentrator lenses must be durable and the silicone material must remain specularly transmitting over a reasonable lifetime in low Earth orbit (LEO) and other space environments. Because of the vulnerability of silicones to atomic oxygen and ultraviolet radiation in LEO these lenses have been coated with a multi-layer metal oxide protective coating. The objective of this research was to evaluate the LEO durability of the multilayer coated silicone for advanced refractive photovoltaic concentrator arrays with respect to optical properties and microstructure. Flat metal oxide coated silicone samples were exposed to ground-laboratory and in-space atomic oxyqen for durability evaluation.

  6. Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates.

    PubMed

    Fan, Zhiyong; Razavi, Haleh; Do, Jae-won; Moriwaki, Aimee; Ergen, Onur; Chueh, Yu-Lun; Leu, Paul W; Ho, Johnny C; Takahashi, Toshitake; Reichertz, Lothar A; Neale, Steven; Yu, Kyoungsik; Wu, Ming; Ager, Joel W; Javey, Ali

    2009-08-01

    Solar energy represents one of the most abundant and yet least harvested sources of renewable energy. In recent years, tremendous progress has been made in developing photovoltaics that can be potentially mass deployed. Of particular interest to cost-effective solar cells is to use novel device structures and materials processing for enabling acceptable efficiencies. In this regard, here, we report the direct growth of highly regular, single-crystalline nanopillar arrays of optically active semiconductors on aluminium substrates that are then configured as solar-cell modules. As an example, we demonstrate a photovoltaic structure that incorporates three-dimensional, single-crystalline n-CdS nanopillars, embedded in polycrystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Through experiments and modelling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the nanopillars. PMID:19578336

  7. Three-dimensional nanopillar-array photovoltaics on low-cost and flexible substrates

    NASA Astrophysics Data System (ADS)

    Fan, Zhiyong; Razavi, Haleh; Do, Jae-Won; Moriwaki, Aimee; Ergen, Onur; Chueh, Yu-Lun; Leu, Paul W.; Ho, Johnny C.; Takahashi, Toshitake; Reichertz, Lothar A.; Neale, Steven; Yu, Kyoungsik; Wu, Ming; Ager, Joel W.; Javey, Ali

    2009-08-01

    Solar energy represents one of the most abundant and yet least harvested sources of renewable energy. In recent years, tremendous progress has been made in developing photovoltaics that can be potentially mass deployed. Of particular interest to cost-effective solar cells is to use novel device structures and materials processing for enabling acceptable efficiencies. In this regard, here, we report the direct growth of highly regular, single-crystalline nanopillar arrays of optically active semiconductors on aluminium substrates that are then configured as solar-cell modules. As an example, we demonstrate a photovoltaic structure that incorporates three-dimensional, single-crystalline n-CdS nanopillars, embedded in polycrystalline thin films of p-CdTe, to enable high absorption of light and efficient collection of the carriers. Through experiments and modelling, we demonstrate the potency of this approach for enabling highly versatile solar modules on both rigid and flexible substrates with enhanced carrier collection efficiency arising from the geometric configuration of the nanopillars.

  8. Theory for optimal design of waveguiding light concentrators in photovoltaic microcell arrays.

    PubMed

    Semichaevsky, Andrey V; Johnson, Harley T; Yoon, Jongseung; Nuzzo, Ralph G; Li, Lanfang; Rogers, John

    2011-06-10

    Efficiency of ultrathin flexible solar photovoltaic silicon microcell arrays can be significantly improved using nonimaging solar concentrators. A fluorophore is introduced to match the solar spectrum and the low-reflectivity wavelength range of Si, reduce the escape losses, and allow the nontracking operation. In this paper we optimize our solar concentrators using a luminescent/nonluminescent photon transport model. Key modeling results are compared quantitatively to experiments and are in good agreement with the latter. Our solar concentrator performance is not limited by the dye self-absorption. Bending deformations of the flexible solar collectors do not result in their indirect gain degradation compared to flat solar concentrators with the same projected area.

  9. Optical absorption enhancement in slanted silicon nanocone hole arrays for solar photovoltaics

    NASA Astrophysics Data System (ADS)

    Zhang, Shu-Yuan; Liu, Wen; Li, Zhao-Feng; Liu, Min; Liu, Yu-Sheng; Wang, Xiao-Dong; Yang, Fu-Hua

    2016-10-01

    We investigate slanted silicon nanocone hole arrays as light absorbing structures for solar photovoltaics via simulation. With only 1-μm equivalent thickness, a maximum short-circuit current density of 34.9 mA/cm2 is obtained. Moreover, by adding an Ag mirror under the whole structure, a short-circuit current density of 37.9 mA/cm2 is attained. It is understood that the optical absorption enhancement mainly results from three aspects. First, the silicon nanocone holes provide a highly efficient antireflection effect. Second, after breaking the geometric symmetry, the slanted silicon nanocone hole supports more resonant absorption modes than vertical structures. Third, the Fabry-Perot resonance enhances the light absorption after adding an Ag mirror. Project supported by the National Natural Science Foundation of China (Grant Nos. 61274066, 61474115, and 61504138) and the National High Technology Research and Development Program of China (Grant No. 2014AA032602).

  10. Evaluation available encapsulation materials for low-cost long-life silicon photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Carmichael, D. C.; Gaines, G. B.; Noel, G. T.; Sliemers, F. A.; Nance, G. P.; Bunk, A. R.; Brockway, M. C.

    1978-01-01

    Experimental evaluation of selected encapsulation designs and materials based on an earlier study which have potential for use in low cost, long-life photovoltaic arrays are reported. The performance of candidate materials and encapsulated cells were evaluated principally for three types of encapsulation designs based on their potentially low materials and processing costs: (1) polymeric coatings, transparent conformal coatings over the cell with a structural-support substrate; (2) polymeric film lamination, cells laminated between two films or sheets of polymeric materials; and (3) glass-covered systems, cells adhesively bonded to a glass cover (superstrate) with a polymeric pottant and a glass or other substrate material. Several other design types, including those utilizing polymer sheet and pottant materials, were also included in the investigation.

  11. Optical characterization of nonimaging dish concentrator for the application of dense-array concentrator photovoltaic system.

    PubMed

    Tan, Ming-Hui; Chong, Kok-Keong; Wong, Chee-Woon

    2014-01-20

    Optimization of the design of a nonimaging dish concentrator (NIDC) for a dense-array concentrator photovoltaic system is presented. A new algorithm has been developed to determine configuration of facet mirrors in a NIDC. Analytical formulas were derived to analyze the optical performance of a NIDC and then compared with a simulated result obtained from a numerical method. Comprehensive analysis of optical performance via analytical method has been carried out based on facet dimension and focal distance of the concentrator with a total reflective area of 120 m2. The result shows that a facet dimension of 49.8 cm, focal distance of 8 m, and solar concentration ratio of 411.8 suns is the most optimized design for the lowest cost-per-output power, which is US$1.93 per watt.

  12. Optical absorption enhancement with low structural-parameter sensitivity in three-dimensional silicon nanocavity array for solar photovoltaics

    NASA Astrophysics Data System (ADS)

    Zhang, Fuqiang; Sun, Ruinan; Hu, Ya; Peng, Kui-Qing

    2016-01-01

    Effective light trapping is essential for improving the efficiency and reducing the cost of thin-film silicon solar cells. Here, we numerically study the optical characteristics of periodic three-dimensional (3D) silicon nanocavity arrays. We found that the 3D silicon nanocavity array shows low sensitivity to geometric structural parameters for photon capture and achieves an outstanding efficiency superior to those of previously reported silicon nanostructures such as a nanowire and a nanohole with the same thickness. This excellence is attributed to a better antireflection capability and more resonant modes. The 3D silicon nanocavity array provides a new light-trapping strategy for thin-film photovoltaic devices.

  13. Broadband High Efficiency Fractal-Like and Diverse Geometry Silicon Nanowire Arrays for Photovoltaic Applications

    NASA Astrophysics Data System (ADS)

    AL-Zoubi, Omar H.

    Solar energy has many advantages over conventional sources of energy. It is abundant, clean and sustainable. One way to convert solar energy directly into electrical energy is by using the photovoltaic solar cells (PVSC). Despite PVSC are becoming economically competitive, they still have high cost and low light to electricity conversion efficiency. Therefore, increasing the efficiency and reducing the cost are key elements for producing economically more competitive PVSC that would have significant impact on energy market and saving environment. A significant percentage of the PVSC cost is due to the materials cost. For that, thin films PVSC have been proposed which offer the benefits of the low amount of material and fabrication costs. Regrettably, thin film PVSC show poor light to electricity conversion efficiency because of many factors especially the high optical losses. To enhance conversion efficiency, numerous techniques have been proposed to reduce the optical losses and to enhance the absorption of light in thin film PVSC. One promising technique is the nanowire (NW) arrays in general and the silicon nanowire (SiNW) arrays in particular. The purpose of this research is to introduce vertically aligned SiNW arrays with enhanced and broadband absorption covering the entire solar spectrum while simultaneously reducing the amount of material used. To this end, we apply new concept for designing SiNW arrays based on employing diversity of physical dimensions, especially radial diversity within certain lattice configurations. In order to study the interaction of light with SiNW arrays and compute their optical properties, electromagnetic numerical modeling is used. A commercial numerical electromagnetic solver software package, high frequency structure simulation (HFSS), is utilized to model the SiNW arrays and to study their optical properties. We studied different geometries factors that affect the optical properties of SiNW arrays. Based on this study, we

  14. Proceedings of the Flat-Plate Solar Array Project Research Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Stations

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Flat Plate Solar Array Project, focuses on advancing technologies relevant to the design and construction of megawatt level central station systems. Photovoltaic modules and arrays for flat plate central station or other large scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost effective configurations. Design, qualification and maintenance issues related to central station arrays derived from the engineering and operating experiences of early applications and parallel laboratory reserch activities are investigated. Technical issues are examined from the viewpoint of the utility engineer, architect/engineer and laboratory researcher. Topics on optimum source circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements, and array operation and maintenance are discussed.

  15. Proceedings of the Flat-Plate Solar Array Project Research Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Stations

    NASA Astrophysics Data System (ADS)

    The Flat Plate Solar Array Project, focuses on advancing technologies relevant to the design and construction of megawatt level central station systems. Photovoltaic modules and arrays for flat plate central station or other large scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost effective configurations. Design, qualification and maintenance issues related to central station arrays derived from the engineering and operating experiences of early applications and parallel laboratory reserch activities are investigated. Technical issues are examined from the viewpoint of the utility engineer, architect/engineer and laboratory researcher. Topics on optimum source circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements, and array operation and maintenance are discussed.

  16. Photovoltaics (PV) as an Eligible Measure in Residential PACE Programs: Benefits and Challenges (Fact Sheet)

    SciTech Connect

    Coughlin, J.

    2010-06-01

    Property Assessed Clean Energy (PACE) financing is one of several new financial models broadening access to clean energy by addressing the barrier of initial capital cost. The majority of the PACE programs in the market today include PV as an eligible measure. PV appeals to homeowners as a way to reduce utility bills, self-generate sustainable power, increase energy independence and demonstrate a commitment to the environment. If substantial state incentives for PV exist, PV projects can be economic under PACE, especially when partnered with good net metering policies. At the same time, PV is expensive relative to other eligible measures with a return on investment horizon that might exceed program targets. This fact sheet reviews the benefits and potential challenges of including PV in PACE programs.

  17. Electrical Performance of the International Space Station U.S. Photovoltaic Array During Bifacial Illumination

    NASA Technical Reports Server (NTRS)

    Delleur, Ann M.; Kerslake, Thomas W.

    2002-01-01

    With the first United States (U.S.) photovoltaic array (PVA) activated on International Space Station (ISS) in December 2000, on-orbit data can now be compared to analytical predictions. Due to ISS operational constraints, it is not always possible to point the front side of the arrays at the Sun. Thus, in many cases, sunlight directly illuminates the backside of the PVA as well as albedo illumination on either the front or the back. During this time, appreciable power is produced since the solar cells are mounted on a thin, solar transparent substrate. It is important to present accurate predictions for both front and backside power generation for mission planning, certification of flight readiness for a given mission, and on-orbit mission support. To provide a more detailed assessment of the ISS power production capability, the authors developed a PVA electrical performance model applicable to generalized bifacial illumination conditions. On-orbit PVA performance data were also collected and analyzed. This paper describes the ISS PVA performance model, and the methods used to reduce orbital performance data. Analyses were performed using SPACE. a NASA-GRC developed computer code for the ISS program office. Results showed a excellent comparison of on-orbit performance data and analytical results.

  18. The application of structural reliability techniques to plume impingement loading of the Space Station Freedom Photovoltaic Array

    NASA Technical Reports Server (NTRS)

    Yunis, Isam S.; Carney, Kelly S.

    1993-01-01

    A new aerospace application of structural reliability techniques is presented, where the applied forces depend on many probabilistic variables. This application is the plume impingement loading of the Space Station Freedom Photovoltaic Arrays. When the space shuttle berths with Space Station Freedom it must brake and maneuver towards the berthing point using its primary jets. The jet exhaust, or plume, may cause high loads on the photovoltaic arrays. The many parameters governing this problem are highly uncertain and random. An approach, using techniques from structural reliability, as opposed to the accepted deterministic methods, is presented which assesses the probability of failure of the array mast due to plume impingement loading. A Monte Carlo simulation of the berthing approach is used to determine the probability distribution of the loading. A probability distribution is also determined for the strength of the array. Structural reliability techniques are then used to assess the array mast design. These techniques are found to be superior to the standard deterministic dynamic transient analysis, for this class of problem. The results show that the probability of failure of the current array mast design, during its 15 year life, is minute.

  19. Flat-plate solar array project of the US Department of Energy's National Photovoltaics Program: Ten years of progress

    NASA Technical Reports Server (NTRS)

    Christensen, Elmer

    1985-01-01

    The Flat-Plate Solar Array (FSA) Project, a Government-sponsored photovoltaics project, was initiated in January 1975 (previously named the Low-Cost Silicon Solar Array Project) to stimulate the development of PV systems for widespread use. Its goal then was to develop PV modules with 10% efficiency, a 20-year lifetime, and a selling price of $0.50 per peak watt of generating capacity (1975 dollars). It was recognized that cost reduction of PV solar-cell and module manufacturing was the key achievement needed if PV power systems were to be economically competitive for large-scale terrestrial use.

  20. The effects of lunar dust accumulation on the performance of photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Katzan, Cynthia M.; Brinker, David J.; Kress, Robert

    1991-01-01

    Lunar base activity, particularly rocket launch and landing, will suspend and transport lunar dust. From preliminary models, the resulting dust accumulation can be significant, even as far as 2 km from the source. For example, at 2 km approximately 0.28 mg/sq cm of dust is anticipated to accumulate after only 10 surface missions with a 26,800 N excursion vehicle. The possible associated penalties in photovoltaic array performance were therefore the subject of experimental as well as theoretical investigation. To evaluate effects of dust accumulation on relative power output, current-voltage characteristics of dust-covered silicon cells were determined under the illumination of a Spectrolab X-25L solar simulator. The dust material used in these experiments was a terrestrial basalt which approximated lunar soil in particle size and composition. Cell short circuit current, an indicator of the penetrating light intensity, was found to decrease exponentially with dust accumulation. This was predicted independently by modeling the light occlusion caused by a growing layer of dust particles. Moreover, the maximum power output of dust-covered cells, derived from the I-V curves, was also found to degrade exponentially. Experimental results are presented and potential implications discussed.

  1. A high-performance photovoltaic concentrator array - The mini-dome Fresnel lens concentrator with 30 percent efficient GaAs/GaSb tandem cells

    NASA Technical Reports Server (NTRS)

    Piszczor, M. F.; Brinker, D. J.; Flood, D. J.; Avery, J. E.; Fraas, L. M.; Fairbanks, E. S.; Yerkes, J. W.; O'Neill, M. J.

    1991-01-01

    A high-efficiency, lightweight space photovoltaic concentrator array is described. Previous work on the minidome Fresnel lens concentrator concept is being integrated with Boeing's 30 percent efficient tandem GaAs/GaSb concentrator cells into a high-performance photovoltaic array. Calculations indicate that, in the near term, such an array can achieve 300 W/sq m at a specific power of 100 W/kg. Emphasis of the program has now shifted to integrating the concentrator lens, tandem cell, and supporting panel structure into a space-qualifiable array. A description is presented of the current status of component and prototype panel testing and the development of a flight panel for the Photovoltaic Array Space Power Plus Diagnostics (PASP PLUS) flight experiment.

  2. Impacts of Array Configuration on Land-Use Requirements for Large-Scale Photovoltaic Deployment in the United States: Preprint

    SciTech Connect

    Denholm, P.; Margolis, R. M.

    2008-05-01

    Land use is often cited as an important issue for renewable energy technologies. In this paper we examine the relationship between land-use requirements for large-scale photovoltaic (PV) deployment in the U.S. and PV-array configuration. We estimate the per capita land requirements for solar PV and find that array configuration is a stronger driver of energy density than regional variations in solar insolation. When deployed horizontally, the PV land area needed to meet 100% of an average U.S. citizen's electricity demand is about 100 m2. This requirement roughly doubles to about 200 m2 when using 1-axis tracking arrays. By comparing these total land-use requirements with other current per capita land uses, we find that land-use requirements of solar photovoltaics are modest, especially when considering the availability of zero impact 'land' on rooftops. Additional work is need to examine the tradeoffs between array spacing, self-shading losses, and land use, along with possible techniques to mitigate land-use impacts of large-scale PV deployment.

  3. Impacts of Array Configuration on Land Use Requirements for Large-Scale Photovoltaic Deployment in the United States

    SciTech Connect

    Denholm, P.; Margolis, R. M.

    2008-01-01

    Land use is often cited as an important issue for renewable energy technologies. In this paper we examine the relationship between land-use requirements for large-scale photovoltaic (PV) deployment in the U.S. and PV-array configuration. We estimate the per capita land requirements for solar PV and find that array configuration is a stronger driver of energy density than regional variations in solar insolation. When deployed horizontally, the PV land area needed to meet 100% of an average U.S. citizen's electricity demand is about 100 m{sup 2}. This requirement roughly doubles to about 200 m{sup 2} when using 1-axis tracking arrays. By comparing these total land-use requirements with other current per capita land uses, we find that land-use requirements of solar photovoltaics are modest, especially when considering the availability of zero impact 'land' on rooftops. Additional work is need to examine the tradeoffs between array spacing, self-shading losses, and land use, along with possible techniques to mitigate land-use impacts of large-scale PV deployment.

  4. Aligned Titania Nanotube Array Thin Films: Growth Kinetics, Branched Structures, and Photovoltaic Characterization

    NASA Astrophysics Data System (ADS)

    Butail, Gorun

    for Vanod<20 V constrains homogeneous branching to occur only V2 ≤ V12 -- V0, where V1 and V 2 are the initial and final anodization voltages and V0 is a voltage offset dependent on the anodization bath chemistry. Our technique circumvents the constraints of multi-bath and multi-temperature methods for branching, and provides a versatile means for creating hierarchically sized and/or interconnected titania nanotubes for applications. Pore microstructure and photovoltaic characteristics of dye-sensitized solar cells fabricated from branched titania nanotube arrays are compared with those from unbranched ones. Branched titania nanotubes result in increased efficiency and short circuit density without any discernible increases in dark current, than in devices with unbranched tubes due to increased internal surface area measured by adsorption isotherms. Enhanced photovoltaic and photocatalytic activities in branched titania nanotubes could be attractive for use in photovoltaics, water purification and energy storage applications.

  5. Relative potentials of concentrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications

    NASA Technical Reports Server (NTRS)

    Borden, C. S.; Schwartz, D. L.

    1984-01-01

    The purpose of this study is to assess the relative economic potentials of concenrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications in the mid-1990's. Specific objectives of this study are to provide information on concentrator photovoltaic collector probabilistic price and efficiency levels to illustrate critical areas of R&D for concentrator cells and collectors, and to compare concentrator and flat-plate PV price and efficiency alternatives for several locations, based on their implied costs of energy. To deal with the uncertainties surrounding research and development activities in general, a probabilistic assessment of commercially achievable concentrator photovoltaic collector efficiencies and prices (at the factory loading dock) is performed. The results of this projection of concentrator photovoltaic technology are then compared with a previous flat-plate module price analysis (performed early in 1983). To focus this analysis on specific collector alternatives and their implied energy costs for different locations, similar two-axis tracking designs are assumed for both concentrator and flat-plate options.

  6. Safety-related requirements for photovoltaic modules and arrays. Final report

    SciTech Connect

    Levins, A.

    1984-03-01

    Underwriters Laboratories has conducted a study to identify and develop safety requirements for photovoltaic module and panel designs and configurations for residential, intermediate, and large scale applications. Concepts for safety systems, where each system is a collection of subsystems which together address the total anticipated hazard situation, are described. Descriptions of hardware, and system usefulness and viability are included. This discussion of safety systems recognizes that there is little history on which to base the expected safety related performance of a photovoltaic system. A comparison of these systems, as against the provisions of the 1984 National Electrical Code covering photovoltaic systems is made. A discussion of the UL investigation of the photovoltaic module evaluated to the provisions of the Proposed UL Standard for Flat-Plate Photovoltaic Modules and Panels is included. Grounding systems, their basis and nature, and the advantages and disadvantages of each are described. The meaning of frame grounding, circuit grounding, and the type of circuit ground are covered. The development of the Standard for Flat-Plate Photovoltaic Modules and Panels has continued, and with both industry comment and a product submittal and listing, the Standard has been refined to a viable document allowing an objective safety review of photovoltaic modules and panels. How this document, and other UL documents would cover investigations of certain other photovoltaic system components is described.

  7. Inner retinal preservation in rat models of retinal degeneration implanted with subretinal photovoltaic arrays.

    PubMed

    Light, Jacob G; Fransen, James W; Adekunle, Adewumi N; Adkins, Alice; Pangeni, Gobinda; Loudin, James; Mathieson, Keith; Palanker, Daniel V; McCall, Maureen A; Pardue, Machelle T

    2014-11-01

    Photovoltaic arrays (PVA) implanted into the subretinal space of patients with retinitis pigmentosa (RP) are designed to electrically stimulate the remaining inner retinal circuitry in response to incident light, thereby recreating a visual signal when photoreceptor function declines or is lost. Preservation of inner retinal circuitry is critical to the fidelity of this transmitted signal to ganglion cells and beyond to higher visual targets. Post-implantation loss of retinal interneurons or excessive glial scarring could diminish and/or eliminate PVA-evoked signal transmission. As such, assessing the morphology of the inner retina in RP animal models with subretinal PVAs is an important step in defining biocompatibility and predicting success of signal transmission. In this study, we used immunohistochemical methods to qualitatively and quantitatively compare inner retinal morphology after the implantation of a PVA in two RP models: the Royal College of Surgeons (RCS) or transgenic S334ter-line 3 (S334ter-3) rhodopsin mutant rat. Two PVA designs were compared. In the RCS rat, we implanted devices in the subretinal space at 4 weeks of age and histologically examined them at 8 weeks of age and found inner retinal morphology preservation with both PVA devices. In the S334ter-3 rat, we implanted devices at 6-12 weeks of age and again, inner retinal morphology was generally preserved with either PVA design 16-26 weeks post-implantation. Specifically, the length of rod bipolar cells and numbers of cholinergic amacrine cells were maintained along with their characteristic inner plexiform lamination patterns. Throughout the implanted retinas we found nonspecific glial reaction, but none showed additional glial scarring at the implant site. Our results indicate that subretinally implanted PVAs are well-tolerated in rodent RP models and that the inner retinal circuitry is preserved, consistent with our published results showing implant-evoked signal transmission. PMID

  8. Inner retinal preservation in rat models of retinal degeneration implanted with subretinal photovoltaic arrays

    PubMed Central

    Light, Jacob G.; Fransen, James W.; Adekunle, Adewumi N.; Adkins, Alice; Pangeni, Gobinda; Loudin, James; Mathieson, Keith; Palanker, Daniel V.; McCall, Maureen A.; Pardue, Machelle T.

    2015-01-01

    Photovoltaic arrays (PVA) implanted into the subretinal space of patients with retinitis pigmentosa (RP) are designed to electrically stimulate the remaining inner retinal circuitry in response to incident light, thereby recreating a visual signal when photoreceptor function declines or is lost. Preservation of inner retinal circuitry is critical to the fidelity of this transmitted signal to ganglion cells and beyond to higher visual targets. Post-implantation loss of retinal interneurons or excessive glial scarring could diminish and/or eliminate PVA-evoked signal transmission. As such, assessing the morphology of the inner retina in RP animal models with subretinal PVAs is an important step in defining biocompatibility and predicting success of signal transmission. In this study, we used immunohistochemical methods to qualitatively and quantitatively compare inner retinal morphology after the implantation of a PVA in two RP models: the Royal College of Surgeons (RCS) or transgenic S334ter-line 3 (S334ter-3) rhodopsin mutant rat. Two PVA designs were compared. In the RCS rat, we implanted devices in the subretinal space at 4 weeks of age and histologically examined them at 8 weeks of age and found inner retinal morphology preservation with both PVA devices. In the S334ter-3 rat, we implanted devices at 6 to 12 weeks of age and again, inner retinal morphology was generally preserved with either PVA design 16 to 26 weeks post implantation. Specifically, the length of rod bipolar cells and numbers of cholinergic amacrine cells were maintained along with their characteristic inner plexiform lamination patterns. Throughout the implanted retinas we found nonspecific glial reaction, but none showed additional glial scarring at the implant site. Our results indicate that subretinally implanted PVAs are well-tolerated in rodent RP models and that the inner retinal circuitry is preserved, consistent with our published results showing implant-evoked signal transmission. PMID

  9. Photovoltaic solar array technology required for three wide scale generating systems for terrestrial applications: rooftop, solar farm, and satellite

    NASA Technical Reports Server (NTRS)

    Berman, P. A.

    1972-01-01

    Three major options for wide-scale generation of photovoltaic energy for terrestrial use are considered: (1) rooftop array, (2) solar farm, and (3) satellite station. The rooftop array would use solar cell arrays on the roofs of residential or commercial buildings; the solar farm would consist of large ground-based arrays, probably in arid areas with high insolation; and the satellite station would consist of an orbiting solar array, many square kilometers in area. The technology advancement requirements necessary for each option are discussed, including cost reduction of solar cells and arrays, weight reduction, resistance to environmental factors, reliability, and fabrication capability, including the availability of raw materials. The majority of the technology advancement requirements are applicable to all three options, making possible a flexible basic approach regardless of the options that may eventually be chosen. No conclusions are drawn as to which option is most advantageous, since the feasibility of each option depends on the success achieved in the technology advancement requirements specified.

  10. Proceedings of the Flat-Plate Solar Array Project Research Forum on the design of flat-plate photovoltaic arrays for central stations

    SciTech Connect

    1983-01-01

    The Flat-Plate Solar Array Project, managed by the Jet Propulsion Laboratory for the US Department of Energy, has focused on advancing technologies relevant to the design and construction of megawatt-level central-station systems. Photovoltaic modules and arrays for flat-plate central-station or other large-scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost-effective configurations. The Central Station Research Forum addressed design, qualification and maintenance issues related to central-station arrays derived from the engineering and operating experiences of early applications and parallel laboratory research activities. Technical issues were examined from the viewpoint of the utility engineer, architect-engineer and laboratory researcher. The forum included presentations on optimum source-circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements and array operation and maintenance. The Research Forum focused on current capabilities as well as design difficulties requiring additional technological thrusts and/or continued research emphasis. Session topic summaries highlighting major points during group discussions, identifying promising technical approaches or areas of future research, are presented.

  11. The wavelength dependent photovoltaic effects caused by two different mechanisms in carbon nanotube film/CuO nanowire array heterodimensional contacts

    SciTech Connect

    Xu Jia; Xu Jinliang; Sun Jialin; Wei Jinquan

    2012-06-18

    Hetrodimensional contacts were fabricated by coating double-walled carbon nanotube (CNT) films on CuO nanowire arrays. Wavelength dependent photovoltaic effects by irradiating the devices with 405, 532, and 1064 nm lasers were observed. Two possible mechanisms responsible for the observed results were discussed. Photoexcitations within CuO nanowires and Schottky barriers in the heterojunctions dominate the photovoltaics in the 405 and 532 nm cases. For the 1064 nm case, the photovoltaic is the result of the excitation within the CNTs and of the heterodimensionality effect. Control experiments on CNT film/CuO granular film hetrodimensional contacts further show the relationship between these two mechanisms.

  12. High-efficiency thin and compact concentrator photovoltaics with micro-solar cells directly attached to a lens array.

    PubMed

    Hayashi, Nobuhiko; Inoue, Daijiro; Matsumoto, Mitsuhiro; Matsushita, Akio; Higuchi, Hiroshi; Aya, Youichirou; Nakagawa, Tohru

    2015-06-01

    We propose a thin and compact concentrator photovoltaic (CPV) module, about 20 mm thick, one tenth thinner than those of conventional CPVs that are widely deployed for mega-solar systems, to broaden CPV application scenarios. We achieved an energy conversion efficiency of 37.1% at a module temperature of 25 °C under sunlight irradiation optimized for our module. Our CPV module has a lens array consisting of 10 mm-square unit lenses and micro solar cells that are directly attached to the lens array, to reduce the focal length of the concentrator and to reduce optical losses due to reflection. The optical loss of the lens in our module is about 9.0%, which is lower than that of conventional CPV modules with secondary optics. This low optical loss enables our CPV module to achieve a high energy conversion efficiency.

  13. The Solar Array Photovoltaic Assembly for the INSAT 4CR Spacecraft Design, Development and In-Orbit Performance

    NASA Astrophysics Data System (ADS)

    Thomas, Joseph; Sudhakar, M.; Agarwal, Anil; Sankaran, M.; Mudramachary, P.

    2008-09-01

    The INSAT 4CR spacecraft, the third in the INSAT 4 series of Indian Space Research Organization (ISRO)'s Communication satellite program, is a high power communication satellite in Geo- stationary Earth Orbit (GEO), configured using the ISRO I2K bus. The primary power is provided by two-wing sun tracking, deployable solar array and the eclipse load requirement is supported by two 70 Ah nickel hydrogen batteries. The power output of the solar array is regulated by Sequential Switching Shunt Regulators to 42V±0.5V. The salient feature of the solar array design is that it uses the new generation multi junction solar cells for all the four panels of size 2.54m x 1.525m to meet the higher power requirement with the available array area. The solar panel fabrication process with the Advanced Triple Junction (ATJ) solar cells from M/s. EMCORE, USA, has been demonstrated for the GEO life cycle through qualification coupon fabrication and testing.This paper describes the INSAT 4CR solar array photovoltaic assemblies design, layout optimization and realization of the Flight Model (FM) panels. It focuses on the power generation prediction, electrical performance measurement under Large Area Pulsed Sun Simulator (LAPSS) and verification of the ground level test results. The indigenously built Geostationary Launch Vehicle (GSLV F04) has successfully launched the INSAT 4CR spacecraft into the orbit on September 2nd, 2007. This paper also presents the analysis of telemetry data to validate the initial phase in-orbit performance of the solar array with prediction.

  14. FACT, Mega-ROSA, SOLAROSA

    NASA Technical Reports Server (NTRS)

    Spence, Brian; White, Steve; Schmid, Kevin; Douglas Mark

    2012-01-01

    all photovoltaic and concentrator flexible blanket technologies, and can readily accommodate standard multijunction and emerging ultra-lightweight IMM (inverted metamorphic) photovoltaic flexible blanket assemblies, as well as ENTECHs Stretched Lens Array (SLA) and DSSs (Deployable Space Systems) FACT, which allows for cost reduction at the array level.

  15. An approach for configuring space photovoltaic tandem arrays based on cell layer performance

    NASA Technical Reports Server (NTRS)

    Flora, C. S.; Dillard, P. A.

    1991-01-01

    Meeting solar array performance goals of 300 W/Kg requires use of solar cells with orbital efficiencies greater than 20 percent. Only multijunction cells and cell layers operating in tandem produce this required efficiency. An approach for defining solar array design concepts that use tandem cell layers involve the following: transforming cell layer performance at standard test conditions to on-orbit performance; optimizing circuit configuration with tandem cell layers; evaluating circuit sensitivity to cell current mismatch; developing array electrical design around selected circuit; and predicting array orbital performance including seasonal variations.

  16. Core-shell heterojunction of silicon nanowire arrays and carbon quantum dots for photovoltaic devices and self-driven photodetectors.

    PubMed

    Xie, Chao; Nie, Biao; Zeng, Longhui; Liang, Feng-Xia; Wang, Ming-Zheng; Luo, Linbao; Feng, Mei; Yu, Yongqiang; Wu, Chun-Yan; Wu, Yucheng; Yu, Shu-Hong

    2014-04-22

    Silicon nanostructure-based solar cells have lately intrigued intensive interest because of their promising potential in next-generation solar energy conversion devices. Herein, we report a silicon nanowire (SiNW) array/carbon quantum dot (CQD) core-shell heterojunction photovoltaic device by directly coating Ag-assisted chemical-etched SiNW arrays with CQDs. The heterojunction with a barrier height of 0.75 eV exhibited excellent rectifying behavior with a rectification ratio of 10(3) at ±0.8 V in the dark and power conversion efficiency (PCE) as high as 9.10% under AM 1.5G irradiation. It is believed that such a high PCE comes from the improved optical absorption as well as the optimized carrier transfer and collection capability. Furthermore, the heterojunction could function as a high-performance self-driven visible light photodetector operating in a wide switching wavelength with good stability, high sensitivity, and fast response speed. It is expected that the present SiNW array/CQD core-shell heterojunction device could find potential applications in future high-performance optoelectronic devices.

  17. An initial analysis of options for a UK feed-in tariff for photovoltaic energy, from an array owner's viewpoint

    NASA Astrophysics Data System (ADS)

    Plater, Steve

    2009-10-01

    The UK government has announced the introduction from April 2010 of a feed-in tariff (FIT) for renewable energy, and initiated a consultation on its design. This paper compares three possible variants of a UK FIT for rooftop photovoltaic (PV) arrays, on the basis of calculated income and array cost payback time, and for three locations (north, central and southern England) and various levels of household electricity consumption. This modelling is based on an FIT rate equivalent to Germany's. It concludes that an FIT which paid only for PV electricity surplus to on-site needs, and exported to the grid, would mean a simple payback time too long to make array purchase appealing. Preferable would be either export to the grid of all PV electricity for FIT payment; or a lower FIT rate for electricity used on-site, plus full FIT for any surplus exported. The latter would involve significantly lower costs in feed-in tariff payments. Finally, the effect of the UK government's illustrative FIT rate for consultation is examined for the same locations and annual consumption levels.

  18. Preliminary Design of a Solar Photovoltaic Array for Net-Zero Energy Buildings at NASA Langley

    NASA Technical Reports Server (NTRS)

    Cole, Stuart K.; DeYoung, Russell J.

    2012-01-01

    An investigation was conducted to evaluate photovoltaic (solar electric systems) systems for a single building at NASA Langley as a representative case for alternative sustainable power generation. Building 1250 in the Science Directorate is comprised of office and laboratory space, and currently uses approximately 250,000 kW/month of electrical power with a projected use of 200,000 kW/month with additional conservation measures. The installation would be applied towards a goal for having Building 1250 classified as a net-zero energy building as it would produce as much energy as it uses over the course of a year. Based on the facility s electrical demand, a photovoltaic system and associated hardware were characterized to determine the optimal system, and understand the possible impacts from its deployment. The findings of this investigation reveal that the 1.9 MW photovoltaic electrical system provides favorable and robust results. The solar electric system should supply the needed sustainable power solution especially if operation and maintenance of the system will be considered a significant component of the system deployment.

  19. The influence of passivation and photovoltaic properties of α-Si:H coverage on silicon nanowire array solar cells

    PubMed Central

    2013-01-01

    Silicon nanowire (SiNW) arrays for radial p-n junction solar cells offer potential advantages of light trapping effects and quick charge collection. Nevertheless, lower open circuit voltages (Voc) lead to lower energy conversion efficiencies. In such cases, the performance of the solar cells depends critically on the quality of the SiNW interfaces. In this study, SiNW core-shell solar cells have been fabricated by growing crystalline silicon (c-Si) nanowires via the metal-assisted chemical etching method and by depositing hydrogenated amorphous silicon (α-Si:H) via the plasma-enhanced chemical vapor deposition (PECVD) method. The influence of deposition parameters on the coverage and, consequently, the passivation and photovoltaic properties of α-Si:H layers on SiNW solar cells have been analyzed. PMID:24059343

  20. Characterization of plasmonic hole arrays as transparent electrical contacts for organic photovoltaics using high-brightness Fourier transform methods

    DOE PAGES

    Camino, Fernando E.; Nam, Chang-Yong; Pang, Yutong T.; Hoy, Jessica; Eisaman, Matthew D.; Black, Charles T.; Sfeir, Matthew Y.

    2014-05-15

    Here we present a methodology for probing light-matter interactions in prototype photovoltaic devices consisting of an organic semiconductor active layer with a semitransparent metal electrical contact exhibiting surface plasmon-based enhanced optical transmission. We achieve high-spectral irradiance in a spot size of less than 100 μm using a high-brightness laser-driven light source and appropriate coupling optics. Spatially resolved Fourier transform photocurrent spectroscopy in the visible and near-infrared spectral regions allows us to measure external quantum efficiency with high sensitivity in small-area devices (<1 mm2). Lastly, this allows for rapid fabrication of variable-pitch sub-wavelength hole arrays in metal films for use asmore » transparent electrical contacts, and evaluation of the evanescent and propagating mode coupling to resonances in the active layer.« less

  1. Characterization of plasmonic hole arrays as transparent electrical contacts for organic photovoltaics using high-brightness Fourier transform methods

    SciTech Connect

    Camino, Fernando E.; Nam, Chang-Yong; Pang, Yutong T.; Hoy, Jessica; Eisaman, Matthew D.; Black, Charles T.; Sfeir, Matthew Y.

    2014-05-15

    Here we present a methodology for probing light-matter interactions in prototype photovoltaic devices consisting of an organic semiconductor active layer with a semitransparent metal electrical contact exhibiting surface plasmon-based enhanced optical transmission. We achieve high-spectral irradiance in a spot size of less than 100 μm using a high-brightness laser-driven light source and appropriate coupling optics. Spatially resolved Fourier transform photocurrent spectroscopy in the visible and near-infrared spectral regions allows us to measure external quantum efficiency with high sensitivity in small-area devices (<1 mm2). Lastly, this allows for rapid fabrication of variable-pitch sub-wavelength hole arrays in metal films for use as transparent electrical contacts, and evaluation of the evanescent and propagating mode coupling to resonances in the active layer.

  2. Dense-array concentrator photovoltaic system using non-imaging dish concentrator and crossed compound parabolic concentrator

    NASA Astrophysics Data System (ADS)

    Chong, Kok-Keong; Yew, Tiong-Keat; Wong, Chee-Woon; Tan, Ming-Hui; Tan, Woei-Chong; Lai, An-Chow; Lim, Boon-Han; Lau, Sing-Liong; Rahman, Faidz Abdul

    2015-04-01

    Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using Fresnel lens and Parabolic dish as solar concentrator that are widely deployed in United States, Australia and Europe are facing great challenge to produce uniformly focused sunlight on the solar cells as to reduce the cost of electrical power generation. The concept of non-imaging optics is not new, but it has not fully explored by the researchers over the world especially in solving the problem of high concentration solar energy, which application is only limited to be a secondary focusing device or low concentration device using Compound Parabolic Concentrator. With the current advancement in the computer processing power, we has successfully invented the non-imaging dish concentrator (NIDC) using numerical simulation method to replace the current parabolic dish as primary focusing device with high solar concentration ratio (more than 400 suns) and large collective area (from 25 to 125 m2). In this paper, we disclose our research and development on dense array CPV system based on non-imaging optics. The geometry of the NIDC is determined using a special computational method. In addition, an array of secondary concentrators, namely crossed compound parabolic concentrators, is also proposed to further focus the concentrated sunlight by the NIDC onto active area of solar cells of the concentrator photovoltaic receiver. The invention maximizes the absorption of concentrated sunlight for the electric power generation system.

  3. Photovoltaic properties of Zr(x)Ti(1-x)O2 solid solution nanowire arrays.

    PubMed

    Gu, Xuehui; Liu, Guohua; Zhang, Min; Zhang, Haifeng; Zhou, Jingran; Guo, Wenbin; Chen, Yu; Ruan, Shengping

    2014-05-01

    In this paper, Zr(0.05Ti(0.95)O2 solid solution nanowire arrays (NWs) were prepared by a low temperature hydrothermal method. The as-prepared NWs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible (UV-vis) spectroscopy. With the doping of Zr content, the band gap of the composite can be varied in a wide range and excellent photoelectric properties of the arrays could be obtained. Moreover, a preliminary study on the photoelectric properties was conducted, which indicates potential applications of the arrays for fabricating high performance ultraviolet photodetectors.

  4. Estimation of the potential array output charge in the performance analysis of stand-alone photovoltaic systems without MPPT (Case study: Mediterranean climate)

    SciTech Connect

    Munoz, F.J.; Echbarthi, I.; Nofuentes, G.; Fuentes, M.; Aguilera, J.

    2009-11-15

    The potential array output energy, E{sub P}, stated by the Joint Research Centre (JRC) in their European Guidelines for the Assessment of Photovoltaic Plants and the IEC Standard 61724 does not estimate properly the potential array output of stand-alone photovoltaic (SAPV) systems without maximum power point tracker (MPPT) as it is the case for SAPV systems with MPPT and grid connected systems. In this way, the main purpose of this paper is to validate an expression that compromises simplicity and accuracy when estimating the potential array output of SAPV systems without MPPT. This issue can be of high interest to photovoltaic (PV) practitioners and experts as it can improve the analysis performance of this type of systems, helping to discriminate better the different losses in this kind of systems. Furthermore, a study of the array potential estimation through different expressions will be developed in order to evaluate which matches better the array potential output in SAPV system without MPPT. Although the analysis will be focused especially in Mediterranean climates, it will be derived some general conclusions that can be considered in other climates. (author)

  5. Photovoltaic cell and array technology development for future unique NASA missions

    NASA Technical Reports Server (NTRS)

    Bailey, S.; Curtis, H.; Piszczor, M.; Surampudi, R.; Hamilton, T.; Rapp, D.; Stella, P.; Mardesich, N.; Mondt, J.; Bunker, R.; Nesmith, B.; Gaddy, E.; Marvin, D.; Kazmerski, L.

    2002-01-01

    A technology review committee from NASA, the U.S. Department of Energy (DOE), and the Air Force Research Lab, was formed to assess solar cell and array technologies required for future NASA science missions.

  6. Measurement techniques and instruments suitable for life-prediction testing of photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Noel, G. T.; Sliemers, F. A.; Deringer, G. C.; Wood, V. E.; Wilkes, K. E.; Gaines, G. B.; Carmichael, D. C.

    1978-01-01

    Array failure modes, relevant materials property changes, and primary degradation mechanisms are discussed as a prerequisite to identifying suitable measurement techniques and instruments. Candidate techniques and instruments are identified on the basis of extensive reviews of published and unpublished information. These methods are organized in six measurement categories - chemical, electrical, optical, thermal, mechanical, and other physicals. Using specified evaluation criteria, the most promising techniques and instruments for use in life prediction tests of arrays were selected.

  7. An advanced space photovoltaic concentrator array using Fresnel lenses, gallium arsenide cells, and prismatic cell covers

    NASA Technical Reports Server (NTRS)

    O'Neill, Mark J.; Piszczor, Michael F.

    1988-01-01

    The current status of a space concentrator array which uses refractive optics, gallium arsenide cells, and prismatic cell covers to achieve excellent performance at a very low array mass is documented. The prismatically covered cells have established records for space cell performance (24.2 percent efficient at 100 AM0 suns and 25 C) and terrestrial single-junction cell performance (29.3 percent efficient at 200 AM1.5 suns and 25 C).

  8. Unlikely Combination of Experiments with a Novel High-Voltage CIGS Photovoltaic Array (Presentation)

    SciTech Connect

    del Cueto, J. A.; Sekulic, B. R.

    2006-05-01

    The goals of this study are to: (1) parameterize current-voltage (I-V) performance over a wide range of illumination and temperatures: (a) 50-1150 W/m{sup 2} irradiance, 5-65 C; (b) obtain array temperature coefficients; and (c) quantify energy production; (2) investigate high-voltage leakage currents from the CIS modules in a high-voltage array: determine dependence on moisture, temperature, and voltage bias and ascertain corrosion problems if any; and (3) study long-term power and energy production stability.

  9. Low Earth orbital atomic oxygen micrometeoroid, and debris interactions with photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Degroh, Kim K.

    1991-01-01

    Polyimide Kapton solar array blankets can be protected from atomic oxygen in low earth orbit if SiO sub x thin film coatings are applied to their surfaces. The useful lifetime of a blanket protected in this manner strongly depends on the number and size of defects in the protective coatings. Atomic oxygen degradation is dominated by undercutting at defects in protective coatings caused by substrate roughness and processing rather than micrometeoroid or debris impacts. Recent findings from the Long Duration Exposure Facility (LDEF) and ground based studies show that interactions between atomic oxygen and silicones may cause grazing and contamination problems which may lead to solar array degradation.

  10. On-Orbit Performance Degradation of the International Space Station P6 Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    Kerslake, Thomas W.; Gustafson, Eric D.

    2003-01-01

    This paper discusses the on-orbit performance and performance degradation of the International Space Station P6 solar array wings (SAWs) from the period of December 2000 through February 2003. Data selection considerations and data reduction methods are reviewed along with the approach for calculating array performance degradation based on measured string shunt current levels. Measured degradation rates are compared with those predicted by the computational tool SPACE and prior degradation rates measured with the same SAW technology on the Mir space station. Initial results show that the measured SAW short-circuit current is degrading 0.2 to 0.5 percent per year. This degradation rate is below the predicted rate of 0.8 percent per year and is well within the 3 percent estimated uncertainty in measured SAW current levels. General contributors to SAW degradation are briefly discussed.

  11. Efficient broadband light absorption in elliptical nanohole arrays for photovoltaic application.

    PubMed

    Xia, Zihuan; Qin, Xuefei; Wu, Yonggang; Pan, Yongdong; Zhou, Jian; Zhang, Zongyi

    2015-12-15

    We propose a perpendicular elliptical silicon nanohole (PE-SiNH) array for light absorption in thin film silicon solar cells. Our analysis shows that this architecture is capable of increasing the absorption of a thin film silicon solar cell by 11.3% in comparison to that of the optimal circular SiNH array. The process of breaking the mirror symmetries is responsible for the increase of the coupled modes. The PE-SiNH structures show additional near-zero spatial Fourier components compared with the circular SiNH structure, which helps to couple more incident light into slow Bloch modes. The mode interaction between adjacent elliptical nanoholes is in favor of the coupling of the incident light into channeling modes and, therefore, enhances light absorption in the short wavelength region.

  12. Novel architecture of plasmon excitation based on self-assembled nanoparticle arrays for photovoltaics.

    PubMed

    Jo, Hanggochnuri; Sohn, Ahrum; Shin, Kyung-Sik; Kumar, Brijesh; Kim, Jae Hyun; Kim, Dong-Wook; Kim, Sang-Woo

    2014-01-22

    An efficient approach to producing hexagonally self-assembled and well-dispersed gold (Au) nanoparticles (NPs) in the pores of porous anodic aluminum oxide (AAO) is reported. This approach is particularly useful for tuning the surface plasmon resonance frequency of Au NPs by varying the effective dielectric constant of AAO. A strongly enhanced Raman spectrum of dye molecule rhodamine 6G using these well-dispersed Au NPs revealed that such a self-assembled Au NP array can induce a strong plasmonic field. Furthermore, we demonstrated a new architecture of plasmon excitation in a bulk heterojunction (BHJ) inverted organic solar cell (IOSC) using the Au NP array with AAO. The optical response of an active layer poly(3-hexylthiophene):(6,6)-phenyl-C61-butyric acid methyl ester was enhanced by this strong plasmonic field associated a well-dispersed Au NP array. A comparative study of AAO with and without Au NPs confirmed plasmonic improvement of the BHJ IOSC. Simulation results showed that Au NPs concentrate the incoming light into a strongly localized field and enhance light absorption in a wide wavelength range.

  13. Low earth orbit durability of protected silicone for refractive photovoltaic concentrator arrays

    NASA Technical Reports Server (NTRS)

    McCollum, Timothy A.; deGroh, Kim K.

    1995-01-01

    Photovoltaic power systems with novel refractive silicone solar concentrators are being developed for use in low Earth orbit (LEO). Because of the vulnerability of silicones to atomic oxygen and ultraviolet radiation, these lenses are coated with a multilayer metal oxide protective coating. The objective of this work was to evaluate the effects of atomic oxygen and thermal exposures on multilayer coated silicone. Samples were exposed to high-fluence ground-laboratory and low-fluence in-space atomic oxygen. Ground testing resulted in decreases in both total and specular transmittance, while in-space exposure resulted in only small decreases in specular transmittance. A contamination film, attributed to exposed silicone at coating crack sites, was found to cause transmittance decreases during ground testing. Propagation of coating cracks was found to be the result of sample heating during exposure. The potential for silicone exposure, with the resulting degradation of optical properties from silicone contamination, indicates that this multilayer coated silicone is not durable for LEO space applications where thermal exposures will cause coating crack development and propagation.

  14. Photovoltaic Roofs

    NASA Technical Reports Server (NTRS)

    Drummond, R. W., Jr.; Shepard, N. F., Jr.

    1984-01-01

    Solar cells perform two functions: waterproofing roof and generating electricity. Sections through horizontal and slanting joints show overlapping modules sealed by L-section rubber strips and side-by-side modules sealed by P-section strips. Water seeping through seals of slanting joints drains along channels. Rooftop photovoltaic array used watertight south facing roof, replacing shingles, tar, and gravel. Concept reduces cost of residential solar-cell array.

  15. Photovoltaic module kit including connector assembly for non-penetrating array installation

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2012-10-23

    A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assembled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting region of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized to slidably receive the male fastener, with all of the connector heads being identical.

  16. Photovoltaic module kit including connector assembly for non-penetrating array installation

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2013-12-31

    A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assempbled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting regions of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized slidably receive the male fastener, with all of the connector heads being identical.

  17. Photovoltaic module kit including connector assembly for non-penetrating array installation

    DOEpatents

    Botkin, Jonathan; Graves, Simon; Danning, Matt; Culligan, Matthew

    2011-11-22

    A PV module kit for non-penetrating rooftop installation, including a plurality of PV modules and a plurality of connectors. Each of the PV modules includes a PV laminate and a frame forming a mounting region assembled thereto. The connectors include a male connector having a male fastener extending from a head, and a female connector having a female fastener assembled within a head. The heads are entirely formed of plastic. The kit provides a mounted array state including a junction at which the mounting region of at least two of the PV modules are aligned and interconnected by engagement of the male connector with the female connector. The so-formed junction is substantially electrically insulated. The plurality of connectors can further include a spacer connector including a head forming a bore sized to slidably receive the male fastener, with all of the connector heads being identical.

  18. Vacuum ultraviolet radiation and thermal cycling effects on atomic oxygen protective photovoltaic array blanket materials

    NASA Technical Reports Server (NTRS)

    Brady, J.; Banks, B.

    1990-01-01

    The importance of synergistic environmental exposure is demonstrated through the evaluation of DuPont 93-1 in simulated LEO environment. Changes in optical properties, surface condition, and mass loss data are described. The qualitative results indicate the necessity for exposure of materials to a series of simulated LEO environments in order to properly determine synergistic effects and demonstrate the overall LEO durability of candidate materials. It is shown that synergistic effects may occur with vacuum thermal cycling combined with VUV radiation followed by atomic oxygen exposure. Testing the durability of candidate solar array blanket materials in a test sequence with necessary synergistic effects makes it possible to determine the appropriate material for providing structural support and maintaining the proper operating temperature for solar cells in the SSF Photovaltaic Power System.

  19. Bilayer-metal assisted chemical etching of silicon microwire arrays for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Wu, R. W.; Yuan, G. D.; Wang, K. C.; Wei, T. B.; Liu, Z. Q.; Wang, G. H.; Wang, J. X.; Li, J. M.

    2016-02-01

    Silicon microwires with lateral dimension from 5 μm to 20 μm and depth as long as 20 μm are prepared by bilayer metal assisted chemical etching (MaCE). A bilayer metal configuration (Metal 1 / Metal 2) was applied to assist etching of Si where metal 1 acts as direct catalyst and metal 2 provides mechanical support. Different metal types were investigated to figure out the influence of metal catalyst on morphology of etched silicon. We find that silicon microwires with vertical side wall are produced when we use Ag/Au bilayer, while cone-like and porous microwires formed when Pt/Au is applied. The different micro-/nano-structures in as-etched silicon are demonstrated to be due to the discrepancy of work function of metal catalyst relative to Si. Further, we constructed a silicon microwire arrays solar cells in a radial p-n junction configurations in a screen printed aluminum paste p-doping process.

  20. Approaches to Future Generation Photovoltaics and Solar Fuels: Quantum Dots, Arrays, and Quantum Dot Solar Cells

    SciTech Connect

    Semonin, O.; Luther, J.; Beard, M.; Johnson, J.; Gao, J.; Nozik, A.

    2012-01-01

    One potential, long-term approach to more efficient and lower cost future generation solar cells for solar electricity and solar fuels is to utilize the unique properties of quantum dots (QDs) to control the relaxation pathways of excited states to enhance multiple exciton generation (MEG). We have studied MEG in close-packed PbSe QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic solution-processable QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies above 5% via nanocrystalline p-n junctions. These solar cells show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy Recent analyses of the major effect of MEG combined with solar concentration on the conversion efficiency of solar cells will also be discussed.

  1. Enhanced photovoltaic performance of fully flexible dye-sensitized solar cells based on the Nb2O5 coated hierarchical TiO2 nanowire-nanosheet arrays

    NASA Astrophysics Data System (ADS)

    Liu, Wenwu; Hong, Chengxun; Wang, Hui-gang; Zhang, Mei; Guo, Min

    2016-02-01

    Nb2O5 coated hierarchical TiO2 nanowire-sheet arrays photoanode was synthesized on flexible Ti-mesh substrate by using a hydrothermal approach. The effect of TiO2 morphology and Nb2O5 coating layer on the photovoltaic performance of the flexible dye sensitized solar cells (DSSCs) based on Ti-mesh supported nanostructures were systematically investigated. Compared to the TiO2 nanowire arrays (NWAs), hierarchical TiO2 nanowire arrays (HNWAs) with enlarged internal surface area and strong light scattering properties exhibited higher overall conversion efficiency. The introduction of thin Nb2O5 coating layers on the surface of the TiO2 HNWAs played a key role in improving the photovoltaic performance of the flexible DSSC. By separating the TiO2 and electrolyte (I-/I3-), the Nb2O5 energy barrier decreased the electron recombination rate and increased electron collection efficiency and injection efficiency, resulting in improved Jsc and Voc. Furthermore, the influence of Nb2O5 coating amounts on the power conversion efficiency were discussed in detail. The fully flexible DSSC based on Nb2O5 coated TiO2 HNWAs films with a thickness of 14 μm displayed a well photovoltaic property of 4.55% (Jsc = 10.50 mA cm-2, Voc = 0.75 V, FF = 0.58). The performance enhancement of the flexible DSSC is largely attributed to the reduced electron recombination, enlarged internal surface area and superior light scattering ability of the formed hierarchical nanostructures.

  2. Long wave focal plane array detector: development and performance assessment of an 8X8 Sterling cooled photovoltaic MCT detector module

    NASA Astrophysics Data System (ADS)

    Rochette, Luc; Smithson, Tracy; Gurgenian, Raymond; St. Pierre, Guy

    2007-09-01

    In June 2005, a newly develop long wave Focal Pane Array (FPA), based on photo-voltaic technology was delivered to the Defense Research & Development of Canada (DRDC). This development was part of technological Demonstration program that was founded by the DRDC. This paper will describe the FPA configuration along with its performance assessment configured in the Air PIRATE FTIR spectrometer. Air PIRATE is an airborne version of the hyper spectral spectrometer used by the Canadian Defense for target identification, as well as chemical agent identification.

  3. Roll-to-roll fabrication of large scale and regular arrays of three-dimensional nanospikes for high efficiency and flexible photovoltaics

    NASA Astrophysics Data System (ADS)

    Leung, Siu-Fung; Gu, Leilei; Zhang, Qianpeng; Tsui, Kwong-Hoi; Shieh, Jia-Min; Shen, Chang-Hong; Hsiao, Tzu-Hsuan; Hsu, Chin-Hung; Lu, Linfeng; Li, Dongdong; Lin, Qingfeng; Fan, Zhiyong

    2014-03-01

    Three-dimensional (3-D) nanostructures have demonstrated enticing potency to boost performance of photovoltaic devices primarily owning to the improved photon capturing capability. Nevertheless, cost-effective and scalable fabrication of regular 3-D nanostructures with decent robustness and flexibility still remains as a challenging task. Meanwhile, establishing rational design guidelines for 3-D nanostructured solar cells with the balanced electrical and optical performance are of paramount importance and in urgent need. Herein, regular arrays of 3-D nanospikes (NSPs) were fabricated on flexible aluminum foil with a roll-to-roll compatible process. The NSPs have precisely controlled geometry and periodicity which allow systematic investigation on geometry dependent optical and electrical performance of the devices with experiments and modeling. Intriguingly, it has been discovered that the efficiency of an amorphous-Si (a-Si) photovoltaic device fabricated on NSPs can be improved by 43%, as compared to its planar counterpart, in an optimal case. Furthermore, large scale flexible NSP solar cell devices have been fabricated and demonstrated. These results not only have shed light on the design rules of high performance nanostructured solar cells, but also demonstrated a highly practical process to fabricate efficient solar panels with 3-D nanostructures, thus may have immediate impact on thin film photovoltaic industry.

  4. Roll-to-roll fabrication of large scale and regular arrays of three-dimensional nanospikes for high efficiency and flexible photovoltaics.

    PubMed

    Leung, Siu-Fung; Gu, Leilei; Zhang, Qianpeng; Tsui, Kwong-Hoi; Shieh, Jia-Min; Shen, Chang-Hong; Hsiao, Tzu-Hsuan; Hsu, Chin-Hung; Lu, Linfeng; Li, Dongdong; Lin, Qingfeng; Fan, Zhiyong

    2014-03-07

    Three-dimensional (3-D) nanostructures have demonstrated enticing potency to boost performance of photovoltaic devices primarily owning to the improved photon capturing capability. Nevertheless, cost-effective and scalable fabrication of regular 3-D nanostructures with decent robustness and flexibility still remains as a challenging task. Meanwhile, establishing rational design guidelines for 3-D nanostructured solar cells with the balanced electrical and optical performance are of paramount importance and in urgent need. Herein, regular arrays of 3-D nanospikes (NSPs) were fabricated on flexible aluminum foil with a roll-to-roll compatible process. The NSPs have precisely controlled geometry and periodicity which allow systematic investigation on geometry dependent optical and electrical performance of the devices with experiments and modeling. Intriguingly, it has been discovered that the efficiency of an amorphous-Si (a-Si) photovoltaic device fabricated on NSPs can be improved by 43%, as compared to its planar counterpart, in an optimal case. Furthermore, large scale flexible NSP solar cell devices have been fabricated and demonstrated. These results not only have shed light on the design rules of high performance nanostructured solar cells, but also demonstrated a highly practical process to fabricate efficient solar panels with 3-D nanostructures, thus may have immediate impact on thin film photovoltaic industry.

  5. Roll-to-roll fabrication of large scale and regular arrays of three-dimensional nanospikes for high efficiency and flexible photovoltaics.

    PubMed

    Leung, Siu-Fung; Gu, Leilei; Zhang, Qianpeng; Tsui, Kwong-Hoi; Shieh, Jia-Min; Shen, Chang-Hong; Hsiao, Tzu-Hsuan; Hsu, Chin-Hung; Lu, Linfeng; Li, Dongdong; Lin, Qingfeng; Fan, Zhiyong

    2014-01-01

    Three-dimensional (3-D) nanostructures have demonstrated enticing potency to boost performance of photovoltaic devices primarily owning to the improved photon capturing capability. Nevertheless, cost-effective and scalable fabrication of regular 3-D nanostructures with decent robustness and flexibility still remains as a challenging task. Meanwhile, establishing rational design guidelines for 3-D nanostructured solar cells with the balanced electrical and optical performance are of paramount importance and in urgent need. Herein, regular arrays of 3-D nanospikes (NSPs) were fabricated on flexible aluminum foil with a roll-to-roll compatible process. The NSPs have precisely controlled geometry and periodicity which allow systematic investigation on geometry dependent optical and electrical performance of the devices with experiments and modeling. Intriguingly, it has been discovered that the efficiency of an amorphous-Si (a-Si) photovoltaic device fabricated on NSPs can be improved by 43%, as compared to its planar counterpart, in an optimal case. Furthermore, large scale flexible NSP solar cell devices have been fabricated and demonstrated. These results not only have shed light on the design rules of high performance nanostructured solar cells, but also demonstrated a highly practical process to fabricate efficient solar panels with 3-D nanostructures, thus may have immediate impact on thin film photovoltaic industry. PMID:24603964

  6. Photovoltaic on-demand high-voltage pulse generator as an on-board power source for electrostatic actuator array

    NASA Astrophysics Data System (ADS)

    Lee, Jeong-Bong; Allen, Mark G.; Rohatgi, Ajeet

    1999-09-01

    The use of amorphous silicon solar cell array high voltage power source as an on-demand wireless power source for electrostatically actuated 32 X 32 micromirror array is presented. The amorphous silicon solar cell array has been reported previously by authors of this paper. In this work, the solar cell array has been used to drive distributed electrostatic actuator array (micromirror array in this particular paper). A 32 X 32 micromirror array has been fabricated and the size of single micromirror is 200 micrometer X 200 micrometer. Static deflection test of micromirrors has been carried out and pull-in voltage of 44 V and releasing voltage of 30 V was found. The electrical output of the solar cell array has been directly connected to the 32 X 32 micromirror array to demonstrate a wireless powered distributed MEMS actuator array. A total solar cell array area of 0.3 cm2 (30 series-interconnected solar cells) were used to drive a part of 32 X 32 micromirror array (a total array area of 0.4 cm2). Motion of multiple numbers of micromirrors was reproducibly observed. The ultimate goal of this research is to achieve power-integrated autonomous MEMS using solar cell array as a miniaturized wireless on-board power source and distributed actuator array as a locomotive engine.

  7. Temperature-sensitive junction transformations for mid-wavelength HgCdTe photovoltaic infrared detector arrays by laser beam induced current microscope

    SciTech Connect

    Qiu, Weicheng; Hu, Weida Lin, Tie; Yin, Fei; Zhang, Bo; Chen, Xiaoshuang; Lu, Wei; Cheng, Xiang'ai Wang, Rui

    2014-11-10

    In this paper, we report on the disappearance of the photosensitive area extension effect and the unusual temperature dependence of junction transformation for mid-wavelength, n-on-p HgCdTe photovoltaic infrared detector arrays. The n-type region is formed by B{sup +} ion implantation on Hg-vacancy-doped p-type HgCdTe. Junction transformations under different temperatures are visually captured by a laser beam induced current microscope. A physical model of temperature dependence on junction transformation is proposed and demonstrated by using numerical simulations. It is shown that Hg-interstitial diffusion and temperature activated defects jointly lead to the p-n junction transformation dependence on temperature, and the weaker mixed conduction compared with long-wavelength HgCdTe photodiode contributes to the disappearance of the photosensitive area extension effect in mid-wavelength HgCdTe infrared detector arrays.

  8. Photonic Design for Photovoltaics

    SciTech Connect

    Kosten, E.; Callahan, D.; Horowitz, K.; Pala, R.; Atwater, H.

    2014-08-28

    We describe photonic design approaches for silicon photovoltaics including i) trapezoidal broadband light trapping structures ii) broadband light trapping with photonic crystal superlattices iii) III-V/Si nanowire arrays designed for broadband light trapping.

  9. Arrays of ZnO/CuIn{sub x}Ga{sub 1−x}Se{sub 2} nanocables with tunable shell composition for efficient photovoltaics

    SciTech Connect

    Akram, Muhammad Aftab; Javed, Sofia; Xu, Jun; Mujahid, Mohammad; Lee, Chun-Sing

    2015-05-28

    Arrays of one-dimensional (1D) nanostructure are receiving much attention for their optoelectronic and photovoltaic applications due to their advantages in light absorption, charge separation, and transportation. In this work, arrays of ZnO/CuIn{sub x}Ga{sub 1−x}Se{sub 2} core/shell nanocables with tunable shell compositions over the full range of 0 ≤ x ≤ 1 have been controllably synthesized. Chemical conversions of ZnO nanorods to a series of ZnO-based nanocables, including ZnO/ZnSe, ZnO/CuSe, ZnO/CuSe/In{sub x}Ga{sub 1−x}, ZnO/CuSe/(In{sub x}Ga{sub 1−x}){sub 2}Se{sub 3}, and ZnO/CuIn{sub x}Ga{sub 1−x}Se{sub 2}, are well designed and successfully achieved. Composition-dependent influences of the CuIn{sub x}Ga{sub 1−x}Se{sub 2} shells on photovoltaic performance are investigated. It is found that the increase in indium content (x) leads to an increase in short-circuit current density (J{sub SC}) but a decrease in open-circuit voltage (V{sub OC}) for the ZnO/CuIn{sub x}Ga{sub 1−x}Se{sub 2} nanocable solar cells. An array of ZnO/CuIn{sub 0.67}Ga{sub 0.33}Se{sub 2} nanocables with a length of ∼1 μm and a shell thickness of ∼10 nm exhibits a bandgap of 1.20 eV, and yields a maximum power conversion efficiency of 1.74% under AM 1.5 G illumination at an intensity of 100 mW/cm{sup 2}. It dramatically surpasses that (0.22%) of the ZnO/CuIn{sub 0.67}Ga{sub 0.33}Se{sub 2} planar thin-film device. Our work reveals that 1D nanoarray allows efficient photovoltaics without using toxic CdS buffer layer.

  10. Measurements and Characterization (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet for the National Center for Photovoltaics: Measurements and Characterization that includes scope, core competencies and capabilities, and contact/web information for Analytical Microscopy, Electro-Optical Characterization, Surface Analysis, and Cell and Module Performance.

  11. Design and Fabrication of Monolithically-Integrated Laterally-Arrayed Multiple Band Gap Solar Cells using Composition-Graded Alloy Nanowires for Spectrum-Splitting Photovoltaic Systems

    NASA Astrophysics Data System (ADS)

    Caselli, Derek

    This dissertation aims to demonstrate a new approach to fabricating solar cells for spectrum-splitting photovoltaic systems with the potential to reduce their cost and complexity of manufacturing, called Monolithically Integrated Laterally Arrayed Multiple Band gap (MILAMB) solar cells. Single crystal semiconductor alloy nanowire (NW) ensembles are grown with the alloy composition and band gap changing continuously across a broad range over the surface of a single substrate in a single, inexpensive growth step by the Dual-Gradient Method. The nanowire ensembles then serve as the absorbing materials in a set of solar cells for spectrum-splitting photovoltaic systems. Preliminary design and simulation studies based on Anderson's model band line-ups were undertaken for CdPbS and InGaN alloys. Systems of six subcells obtained efficiencies in the 32-38% range for CdPbS and 34-40% for InGaN at 1-240 suns, though both materials systems require significant development before these results could be achieved experimentally. For an experimental demonstration, CdSSe was selected due to its availability. Proof-of-concept CdSSe nanowire ensemble solar cells with two subcells were fabricated simultaneously on one substrate. I-V characterization under 1 sun AM1.5G conditions yielded open-circuit voltages (Voc) up to 307 and 173 mV and short-circuit current densities (Jsc) up to 0.091 and 0.974 mA/cm2 for the CdS- and CdSe-rich cells, respectively. Similar thin film cells were also fabricated for comparison. The nanowire cells showed substantially higher Voc than the film cells, which was attributed to higher material quality in the CdSSe absorber. I-V measurements were also conducted with optical filters to simulate a simple form of spectrum-splitting. The CdS-rich cells showed uniformly higher Voc and fill factor (FF) than the CdSe-rich cells, as expected due to their larger band gaps. This suggested higher power density was produced by the CdS-rich cells on the single

  12. BMDO photovoltaics program overview

    NASA Technical Reports Server (NTRS)

    Caveny, Leonard H.; Allen, Douglas M.

    1994-01-01

    This is an overview of the Ballistic Missile Defense Organization (BMDO) Photovoltaic Program. Areas discussed are: (1) BMDO advanced Solar Array program; (2) Brilliant Eyes type satellites; (3) Electric propulsion; (4) Contractor Solar arrays; (5) Iofee Concentrator and Cell development; (6) Entech linear mini-dome concentrator; and (7) Flight test update/plans.

  13. Assessment of High-Voltage Photovoltaic Technologies for the Design of a Direct Drive Hall Effect Thruster Solar Array

    NASA Technical Reports Server (NTRS)

    Mikellides, I. G.; Jongeward, G. A.; Schneider, T.; Carruth, M. R.; Peterson, T.; Kerslake, T. W.; Snyder, D.; Ferguson, D.; Hoskins, A.

    2004-01-01

    A three-year program to develop a Direct Drive Hall-Effect Thruster system (D2HET) begun in 2001 as part of the NASA Advanced Cross-Enterprise Technology Development initiative. The system, which is expected to reduce significantly the power processing, complexity, weight, and cost over conventional low-voltage systems, will employ solar arrays that operate at voltages higher than (or equal to) 300 V. The lessons learned from the development of the technology also promise to become a stepping-stone for the production of the next generation of power systems employing high voltage solar arrays. This paper summarizes the results from experiments conducted mainly at the NASA Marshal Space Flight Center with two main solar array technologies. The experiments focused on electron collection and arcing studies, when the solar cells operated at high voltages. The tests utilized small coupons representative of each solar array technology. A hollow cathode was used to emulate parts of the induced environment on the solar arrays, mostly the low-energy charge-exchange plasma (1012-1013 m-3 and 0.5-1 eV). Results and conclusions from modeling of electron collection are also summarized. The observations from the total effort are used to propose a preliminary, new solar array design for 2 kW and 30-40 kW class, deep space missions that may employ a single or a cluster of Hall- Effect thrusters.

  14. Photovoltaic system controller

    SciTech Connect

    Gerken, K.F.; Sullivan, R.A.

    1989-12-19

    This patent describes a photovoltaic system controller for utilization with a photovoltaic power system including at least a photovoltaic array, a system battery adapted to be charged by the array and a load adapted to be powered by the battery. The controller comprising a microprocessor having an erasable programmable memory. The microprocessor having means to receive input data from the array, the battery and the load. The microprocessor having means to evaluate the input data in relation to at least one predetermined setpoint, the microprocessor in response to the evaluation being adapted to disconnect the battery from the array or to disconnect the load from the battery. The setpoint being adapted to be adjusted to a second setpoint by adjustment means, and the erasable programmable memory being adapted to be changed whereby the evaluation performed by the microprocessor is also changed.

  15. Quantitative analysis of the size effect of room temperature nanoimprinted P3HT nanopillar arrays on the photovoltaic performance

    NASA Astrophysics Data System (ADS)

    Ding, Guangzhu; Li, Chao; Li, Xiaohui; Wu, Yangjiang; Liu, Jieping; Li, Yaowen; Hu, Zhijun; Li, Yongfang

    2015-06-01

    We develop a solvent-assisted room temperature nanoimprint lithography (SART-NIL) technique to fabricate an ideal active layer consisting of poly(3-hexylthiophene) nanopillar arrays surrounded by [6,6]-phenyl-C61-butyric acid methyl ester. Characterization by scanning electron microscopy, two-dimensional grazing incidence wide angle X-rays diffraction, and conducting atomic force microscopy reveals that the SART-NIL technique can precisely control the size of P3HT nanopillar arrays. With the decrease in diameters of P3HT nanopillar arrays, the P3HT nanopillar arrays exhibit a more preferable face-on molecular orientation, enhanced UV-vis absorption and higher conducting ability along the direction perpendicular to the substrate. The ordered bulk heterojunction film consisting of P3HT nanopillar arrays with a diameter of ~45 nm (OBHJ-45) gives face-on orientation, a high interfacial area of 2.87, a high conducting ability of ~130 pA and efficient exciton diffusion and dissociation. The polymer solar cell (PSC) based on an OBHJ-45 film exhibits a significantly improved device performance compared with those of PSCs based on the P3HT nanoapillar arrays with diameters ~100 nm and ~60 nm. We believe that the SART-NIL technique is a powerful tool for fabricating an ideal active layer for high performance PSCs.We develop a solvent-assisted room temperature nanoimprint lithography (SART-NIL) technique to fabricate an ideal active layer consisting of poly(3-hexylthiophene) nanopillar arrays surrounded by [6,6]-phenyl-C61-butyric acid methyl ester. Characterization by scanning electron microscopy, two-dimensional grazing incidence wide angle X-rays diffraction, and conducting atomic force microscopy reveals that the SART-NIL technique can precisely control the size of P3HT nanopillar arrays. With the decrease in diameters of P3HT nanopillar arrays, the P3HT nanopillar arrays exhibit a more preferable face-on molecular orientation, enhanced UV-vis absorption and higher

  16. Recent advances in the EPRI high-concentration photovoltaic program. Volume 2: Module and array programs; design, construction, and testing; system and open issues: Interim report

    SciTech Connect

    McNaughton, W.P.; Richman, R.H.

    1992-02-01

    By the early 1980s, Stanford University under contract with the Electric Power Research Institute (EPRI) produced a point-contact photovoltaic cell that has established a number of world record achievements. In 1984 a conceptual design was proposed for a cell package, module, and array system for use in utility-scale commercial power production. Since 1984, EPRI has moved the laboratory concept forward toward commercial application. More than 1500 high concentration cells have been produced in the evolutionary process. Approximately 700 of those cells have been or are presently being installed in fully operational modules for field tests. Over 130 modules have been constructed and are in field testing for electrical, thermal or weathering tests. Two full-sized array structures (each containing 60 instrumented ``thermal`` modules) have been constructed and continue to undergo field testing for alignment, performance, and reliability. This two volume report reviews the key challenges that have confronted the development of a commercial system and describes the program response to those challenges. The intent is to inform interested readers -- utilities, commercializers, researchers -- as to the primary developments and test results that have been achieved. A considerable body of ``raw data`` has been included so that interested researchers can draw their own conclusions without needing to refer to the source documents. Volume 1 discusses design fabrication and performance of the cell; design, construction and testing of the cell package and the design, fabrication and testing of the optical system. Volume 2 reviews the module and array programs, discusses other system issues and presents a short review of the technology`s open issues.

  17. Study of a micro-concentrated photovoltaic system based on Cu(In,Ga)Se2 microcells array.

    PubMed

    Jutteau, Sebastien; Guillemoles, Jean-François; Paire, Myriam

    2016-08-20

    We study a micro-concentrated photovoltaic (CPV) system based on micro solar cells made from a thin film technology, Cu(In,Ga)Se2. We designed, using the ray-tracing software Zemax OpticStudio 14, an optical system adapted and integrated to the microcells, with only spherical lenses. The designed architecture has a magnification factor of 100× for an optical efficiency of 85% and an acceptance angle of ±3.5°, without anti-reflective coating. An experimental study is realized to fabricate the first generation prototype on a 5  cm×5  cm substrate. A mini-module achieved a concentration ratio of 72× under AM1.5G, and an absolute efficiency gain of 1.8% for a final aperture area efficiency of 12.6%. PMID:27556986

  18. The relationship between nanoscale architecture and function in photovoltaic multichromophoric arrays as visualized by Kelvin probe force microscopy.

    PubMed

    Palermo, Vincenzo; Otten, Matthijs B J; Liscio, Andrea; Schwartz, Erik; de Witte, Pieter A J; Castriciano, Maria Angela; Wienk, Martijn M; Nolde, Fabian; De Luca, Giovanna; Cornelissen, Jeroen J L M; Janssen, René A J; Müllen, Klaus; Rowan, Alan E; Nolte, Roeland J M; Samorì, Paolo

    2008-11-01

    The physicochemical properties of organic (multi)component films for optoelectronic applications depend on both the mesoscopic and nanoscale architectures within the semiconducting material. Two main classes of semiconducting materials are commonly used: polymers and (liquid) crystals of small aromatic molecules. Whereas polymers (e.g., polyphenylenevinylenes and polythiophenes) are easy to process in solution in thin and uniform layers, small molecules can form highly defined (liquid) crystals featuring high charge mobilities. Herein, we combine the two material types by employing structurally well-defined polyisocyanopeptide polymers as scaffolds to precisely arrange thousands of electron-accepting molecules, namely, perylenebis(dicarboximides) (PDIs), in defined chromophoric wires with lengths of hundreds of nanometers. The polymer backbone enforces high control over the spatial location of PDI dyes, favoring both enhanced exciton and charge transfer. When blended with an electron-donor system such as regioregular poly(3-hexylthiophene), this polymeric PDI shows a relative improvement in charge generation and diffusion with respect to monomeric, aggregated PDI. In order to correlate this enhanced behavior with respect to the architecture, atomic force microscopy investigations on the mixtures were carried out. These studies revealed that the two polymers form interpenetrated bundles having a nanophase-segregated character and featuring a high density of contact points between the two different phases. In order to visualize the relationship between the architecture and the photovoltaic efficiency, Kelvin probe force microscopy measurements were carried out on submonolayer-thick films. This technique allowed for the first time the direct visualization of the photovoltaic activity occurring in such a nanoscale phase-segregated ultrathin film with true nanoscale spatial resolution, thus making possible a study of the correlation between function and architecture

  19. Determination of charge-carrier diffusion length in the photosensing layer of HgCdTe n-on-p photovoltaic infrared focal plane array detectors

    SciTech Connect

    Vishnyakov, A. V.; Stuchinsky, V. A. Brunev, D. V.; Zverev, A. V.; Dvoretsky, S. A.

    2014-03-03

    In the present paper, we propose a method for evaluating the bulk diffusion length of minority charge carriers in the photosensing layer of photovoltaic focal plane array (FPA) photodetectors. The method is based on scanning a strip-shaped illumination spot with one of the detector diodes at a low level of photocurrents j{sub ph} being registered; such scanning provides data for subsequent analysis of measured spot-scan profiles within a simple diffusion model. The asymptotic behavior of the effective (at j{sub ph} ≠ 0) charge-carrier diffusion length l{sub d} {sub eff} as a function of j{sub ph} for j{sub ph} → 0 inferred from our experimental data proved to be consistent with the behavior of l{sub d} {sub eff} vs j{sub ph} as predicted by the model, while the obtained values of the bulk diffusion length of minority carriers (electrons) in the p-HgCdTe film of investigated HgCdTe n-on-p FPA photodetectors were found to be in a good agreement with the previously reported carrier diffusion-length values for HgCdTe.

  20. Combination solar photovoltaic heat engine energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  1. Oxidation and protection of fiberglass-epoxy composite masts for photovoltaic arrays in the low Earth orbital environment

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Paulsen, Phillip E.; Brady, Joyce A.; Ciancone, Michael L.

    1988-01-01

    Fiberglass-epoxy composites are considered for use as structural members for the mast of the space station solar array panel. The low Earth orbital environment in which space station is to operate is composed mainly of atomic oxygen, which has been shown to cause erosion of many organic materials and some metals. Ground based testing in a plasma asher was performed to determine the extent of degradation of fiberglass-epoxy composites when exposed to a simulated atomic oxygen environment. During exposure, the epoxy at the surface of the composite was oxidized, exposing individual glass fibers which could easily be removed. Several methods of protecting the composite were evaluated in an atomic oxygen environment and with thermal cycling and flexing. The protection techniques evaluated to date include an aluminum braid covering, an indium-tin eutectic and a silicone based paint. The open aluminum braid offered little protection while the CV-1144 coating offered some initial protection against atomic oxygen, but appears to develop cracks which accelerate degradation when flexed. Coatings such as the In-Sn eutectic may provide adequate protection by containing the glass fibers even though mass loss still occurs.

  2. Semiconductor Quantum Dots and Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells

    SciTech Connect

    Nozik, Arthur J.; Beard, Matthew C.; Luther, Joseph M.; Law, Matt; Ellingson, Randy J.; Johnson, Justin C.

    2010-10-14

    Here, we will first briefly summarize the general principles of QD synthesis using our previous work on InP as an example. Then we will focus on QDs of the IV-VI Pb chalcogenides (PbSe, PbS, and PbTe) and Si QDs because these were among the first QDs that were reported to produce multiple excitons upon absorbing single photons of appropriate energy (a process we call multiple exciton generation (MEG)). We note that in addition to Si and the Pb-VI QDs, two other semiconductor systems (III-V InP QDs(56) and II-VI core-shell CdTe/CdSe QDs(57)) were very recently reported to also produce MEG. Then we will discuss photogenerated carrier dynamics in QDs, including the issues and controversies related to the cooling of hot carriers and the magnitude and significance of MEG in QDs. Finally, we will discuss applications of QDs and QD arrays in novel quantum dot PV cells, where multiple exciton generation from single photons could yield significantly higher PV conversion efficiencies.

  3. Versatile control of metal-assisted chemical etching for vertical silicon microwire arrays and their photovoltaic applications

    PubMed Central

    Um, Han-Don; Kim, Namwoo; Lee, Kangmin; Hwang, Inchan; Hoon Seo, Ji; Yu, Young J.; Duane, Peter; Wober, Munib; Seo, Kwanyong

    2015-01-01

    A systematic study was conducted into the use of metal-assisted chemical etching (MacEtch) to fabricate vertical Si microwire arrays, with several models being studied for the efficient redox reaction of reactants with silicon through a metal catalyst by varying such parameters as the thickness and morphology of the metal film. By optimizing the MacEtch conditions, high-quality vertical Si microwires were successfully fabricated with lengths of up to 23.2 μm, which, when applied in a solar cell, achieved a conversion efficiency of up to 13.0%. These solar cells also exhibited an open-circuit voltage of 547.7 mV, a short-circuit current density of 33.2 mA/cm2, and a fill factor of 71.3% by virtue of the enhanced light absorption and effective carrier collection provided by the Si microwires. The use of MacEtch to fabricate high-quality Si microwires therefore presents a unique opportunity to develop cost-effective and highly efficient solar cells. PMID:26060095

  4. Chemical Fabrication Used to Produce Thin-Film Materials for High Power-to- Weight-Ratio Space Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Rybicki, George C.; Raffaelle, Ryne P.; Harris, Jerry D.; Hehemann, David G.; Junek, William; Gorse, Joseph; Thompson, Tracy L.; Hollingsworth, Jennifer A.; Buhro, William E.

    2000-01-01

    The key to achieving high specific power (watts per kilogram) space solar arrays is the development of a high-efficiency, thin-film solar cell that can be fabricated directly on a flexible, lightweight, space-qualified durable substrate such as Kapton (DuPont) or other polyimide or suitable polymer film. Cell efficiencies approaching 20 percent at AM0 (air mass zero) are required. Current thin-film cell fabrication approaches are limited by either (1) the ultimate efficiency that can be achieved with the device material and structure or (2) the requirement for high-temperature deposition processes that are incompatible with all presently known flexible polyimide or other polymer substrate materials. Cell fabrication processes must be developed that will produce high-efficiency cells at temperatures below 400 degrees Celsius, and preferably below 300 degress Celsius to minimize the problems associated with the difference between the coefficients of thermal expansion of the substrate and thin-film solar cell and/or the decomposition of the substrate.

  5. Do photovoltaics have a future

    NASA Technical Reports Server (NTRS)

    Williams, B. F.

    1979-01-01

    There is major concern as to the economic practicality of widespread terrestrial use because of the high cost of the photovoltaic arrays themselves. Based on their high efficiency, photovoltaic collectors should be one of the cheapest forms of energy generators known. Present photovoltaic panels are violating the trend of lower costs with increasing efficiency due to their reliance on expensive materials. A medium technology solution should provide electricity competitive with the existing medium to high technology energy generators such as oil, coal, gas, and nuclear fission thermal plants. Programs to reduce the cost of silicon and develop reliable thin film materials have a realistic chance of producing cost effective photovoltaic panels.

  6. Energy Systems Integration: NREL + Solectria (Fact Sheet)

    SciTech Connect

    Not Available

    2015-02-01

    This fact sheet describes the collaboration between NREL and Solectria at the Energy Systems Integration Facility (ESIF) to to develop 500- and 750-kilowatt photovoltaic (PV) inverters with advanced features that can support the electric grid.

  7. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Leo, Karl

    2016-08-01

    Organic photovoltaics are on the verge of revolutionizing building-integrated photovoltaics. For other applications, however, several basic open scientific questions need answering to, in particular, further improve energy-conversion efficiency and lifetime.

  8. Photovoltaic device

    DOEpatents

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-06-02

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device with a multilayered photovoltaic cell assembly and a body portion joined at an interface region and including an intermediate layer, at least one interconnecting structural member, relieving feature, unique component geometry, or any combination thereof.

  9. Photovoltaic device

    DOEpatents

    Reese, Jason A.; Keenihan, James R.; Gaston, Ryan S.; Kauffmann, Keith L.; Langmaid, Joseph A.; Lopez, Leonardo C.; Maak, Kevin D.; Mills, Michael E.; Ramesh, Narayan; Teli, Samar R.

    2015-09-01

    The present invention is premised upon an improved photovoltaic device ("PV device"), more particularly to an improved photovoltaic device (10) with a multilayered photovoltaic cell assembly (100) and a body portion (200) joined at an interface region (410) and including an intermediate layer (500), at least one interconnecting structural member (1500), relieving feature (2500), unique component geometry, or any combination thereof.

  10. Magnetic Resonance Facility (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

  11. Alcohol Facts

    MedlinePlus

    ... raquo Alcohol Facts Alcohol Facts Listen Drinks like beer, malt liquor, wine, and hard liquor contain alcohol. Alcohol is the ingredient that gets you drunk. Hard liquor—such as whiskey, rum, or gin—has more ...

  12. Organ Facts

    MedlinePlus

    ... Donation Home / Before The Transplant / Organ Facts Organ Facts Heart Lung Heart/Lung Kidney Pancreas Kidney/Pancreas Liver ... Receiving "the call" About the Operation Heart Lung Heart/Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Organ Facts Here you can find valuable information about organs ...

  13. Liver Facts

    MedlinePlus

    ... Home / Before The Transplant / Organ Facts / Liver Organ Facts Heart Lung Heart/Lung Kidney Pancreas Kidney/Pancreas Liver ... Receiving "the call" About the Operation Heart Lung Heart/Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Liver Facts How the Liver Works The liver is one ...

  14. Kidney Facts

    MedlinePlus

    ... Home / Before The Transplant / Organ Facts / Kidney Organ Facts Heart Lung Heart/Lung Kidney Pancreas Kidney/Pancreas Liver ... Receiving "the call" About the Operation Heart Lung Heart/Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Kidney Facts The kidneys are a pair of reddish-brown ...

  15. High voltage photovoltaic power converter

    DOEpatents

    Haigh, Ronald E.; Wojtczuk, Steve; Jacobson, Gerard F.; Hagans, Karla G.

    2001-01-01

    An array of independently connected photovoltaic cells on a semi-insulating substrate contains reflective coatings between the cells to enhance efficiency. A uniform, flat top laser beam profile is illuminated upon the array to produce electrical current having high voltage. An essentially wireless system includes a laser energy source being fed through optic fiber and cast upon the photovoltaic cell array to prevent stray electrical signals prior to use of the current from the array. Direct bandgap, single crystal semiconductor materials, such as GaAs, are commonly used in the array. Useful applications of the system include locations where high voltages are provided to confined spaces such as in explosive detonation, accelerators, photo cathodes and medical appliances.

  16. The structure and photovoltaic properties of double-shell TiO{sub 2}/ZnSe/CdSe nanocable arrays synthesized by using TiO{sub 2}/ZnO nanocables template

    SciTech Connect

    Wang, Baoyuan; Liu, Tian; Xia, Chen; Zhou, Fangyuan; He, Fan; Liu, Rong; Hu, Yunxia; Wang, Hao

    2014-11-15

    Highlights: • The ZnSe/CdSe/TiO{sub 2} nanocable arrays were synthesized. • The TiO{sub 2}/ZnSe/CdSe double shell electrode shown better photovoltaic performance. • A stepwise band alignment structure was constructed in the TiO{sub 2}/ZnSe/CdSe electrode. • A highest power conversion efficiency of 1.33% has been obtained. - Abstract: A simple method was reported for the first time to synthesize ZnSe/CdSe co-sensitized TiO{sub 2} nanorod arrays. TiO{sub 2}/ZnO nanocables were firstly prepared by magnetic sputtering ZnO films on TiO{sub 2} nanorod arrays, and the TiO{sub 2}/ZnSe nanocables were synthesized by selenization of TiO{sub 2}/ZnO nanocables with Se{sup 2−} ions. Finally, CdSe quantum dots (QDs) were electrodeposited on the TiO{sub 2}/ZnSe nanocables forming a TiO{sub 2}/ZnSe/CdSe tri-layer configuration. It is found that the tri-layer photoelectrode has a complementary effect in the light absorption, while the ZnSe shell acts as a blocking layer to retarding the interfacial recombination. Furthermore, a stepwise band alignment structure was constructed in the TiO{sub 2}/ZnSe/CdSe electrode, which greatly speeds up the transfer rate of photoexcited electrons from CdSe to TiO{sub 2}. Thus, the TiO{sub 2}/ZnSe/CdSe electrode presented better photovoltaic performance than the single shell. Through optimization the thickness of ZnSe layer in the TiO{sub 2}/ZnSe/CdSe photoelectrode, a highest power conversion efficiency of 1.33% was obtained.

  17. Photovoltaic Energy Program Overview Fiscal Year 1996

    SciTech Connect

    1997-05-01

    Significant activities in the National Photovoltaic Program are reported for each of the three main program elements. In Research and Development, advances in thin-film materials and crystalline silicon materials are described. The Technology Development report describes activities in photovoltaic manufacturing technology, industrial expansion, module and array development, and testing photovoltaic system components. Systems Engineering and Applications projects described include projects with government agencies, projects with utilities, documentation of performance for international applications, and product certification.

  18. Voltage Regulators for Photovoltaic Systems

    NASA Technical Reports Server (NTRS)

    Delombard, R.

    1986-01-01

    Two simple circuits developed to provide voltage regulation for highvoltage (i.e., is greater than 75 volts) and low-voltage (i.e., is less than 36 volts) photovoltaic/battery power systems. Use of these circuits results in voltage regulator small, low-cost, and reliable, with very low power dissipation. Simple oscillator circuit controls photovoltaic-array current to regulate system voltage and control battery charging. Circuit senses battery (and system) voltage and adjusts array current to keep battery voltage from exceeding maximum voltage.

  19. Trends in Space Photovoltaic Technology

    NASA Technical Reports Server (NTRS)

    Scott-Monck, J. A.

    1984-01-01

    The current status of silicon and gallium arsenide (GaAs) solar cell technology is described, and anticipated near and far term projections of photovoltaic cell performance are provided. It is shown that current ultrathin silicon and near term GaAs solar cells provide substantial enhancement of planar solar array performance. The advantages of utililizing GaAs cells in high concentration arrays is discussed. Evidence is provided to support the view that photovoltaic offers a viable means of supporting long term space objectives.

  20. Semiconductors: In Situ Processing of Photovoltaic Devices

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.

    1998-01-01

    The possible processing of semiconductor photovoltaic devices is discussed. The requirements for lunar PV cells is reviewed, and the key challenges involved in their manufacturing are investigated. A schematic diagram of a passivated emitter and rear cell (PERC) is presented. The possible fabrication of large photovoltaic arrays in space from lunar materials is also discussed.

  1. Photovoltaic cell

    DOEpatents

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  2. Photovoltaic panel support assembly

    SciTech Connect

    Barker, J.M.; Underwood, J.C.; Shingleton, J.

    1993-07-20

    A solar energy electrical power source is described comprising in combination at least two flat photovoltaic panels disposed side-by-side in co-planar relation with one another, a pivot shaft extending transversely across the panels, at least two supports spaced apart lengthwise of the pivot shaft, means for connecting the pivot shaft to the at least two supports, attachment means for connecting the at least two panels to the pivot shaft so that the panels can pivot about the longitudinal axis of the shaft, coupling means mechanically coupling all of the panels together so as to form a unified flat array, and selectively operable drive means for mechanically pivoting the unified flat array about the axis; wherein each of the flat photovoltaic panels comprises at least two modules each comprising a plurality of electrically interconnected photovoltaic cells, the at least two modules being aligned along a line extending at a right angle to the pivot shaft, and the coupling means comprises (a) an elongate member extending parallel to and spaced from the pivot shaft and (b) means for attaching the elongate member to the panels; and further wherein each flat photovoltaic panel comprises a unitary frame consisting of a pair of end frame members extending parallel to the pivot shaft, a pair of side frame members extending between and connected to the end frame members, and a pair of spaced apart cross frame members, with one of the two modules being embraced by and secured to the side frame members and a first one of each of the end and cross frame members, and the other of the two modules being embraced by and secured to the side frame members and the second one of each of the end and cross frame members, whereby the gap created by the spaced apart cross frame members allow air to pass between them in order to reduce the sail effect when the solar array is subjected to buffeting winds.

  3. Reverse bias protected solar array with integrated bypass battery

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A (Inventor)

    2012-01-01

    A method for protecting the photovoltaic cells in a photovoltaic (PV) array from reverse bias damage by utilizing a rechargeable battery for bypassing current from a shaded photovoltaic cell or group of cells, avoiding the need for a bypass diode. Further, the method mitigates the voltage degradation of a PV array caused by shaded cells.

  4. Design considerations for lunar base photovoltaic power systems

    NASA Technical Reports Server (NTRS)

    Hickman, J. M.; Curtis, Henry B.; Landis, Geoffrey A.

    1990-01-01

    A survey was made of factors that may affect the design of photovoltaic arrays for a lunar base. These factors, which include the lunar environment and system design criteria, are examined. A photovoltaic power system design with a triangular array geometry is discussed and compared to a nuclear reactor power system and a power system utilizing both nuclear and solar power sources.

  5. Design considerations for lunar base photovoltaic power systems

    NASA Technical Reports Server (NTRS)

    Hickman, J. Mark; Curtis, Henry B.; Landis, Geoffrey A.

    1990-01-01

    A survey was made of factors that may affect the design of photovoltaic arrays for a lunar base. These factors, which include the lunar environment and system design criteria, are examined. A photovoltaic power system design with a triangular array geometry is discussed and compared to a nuclear reactor power systems and a power system utilizing both nuclear and solar power sources.

  6. Photovoltaic self-assembly.

    SciTech Connect

    Lavin, Judith; Kemp, Richard Alan; Stewart, Constantine A.

    2010-10-01

    This late-start LDRD was focused on the application of chemical principles of self-assembly on the ordering and placement of photovoltaic cells in a module. The drive for this chemical-based self-assembly stems from the escalating prices in the 'pick-and-place' technology currently used in the MEMS industries as the size of chips decreases. The chemical self-assembly principles are well-known on a molecular scale in other material science systems but to date had not been applied to the assembly of cells in a photovoltaic array or module. We explored several types of chemical-based self-assembly techniques, including gold-thiol interactions, liquid polymer binding, and hydrophobic-hydrophilic interactions designed to array both Si and GaAs PV chips onto a substrate. Additional research was focused on the modification of PV cells in an effort to gain control over the facial directionality of the cells in a solvent-based environment. Despite being a small footprint research project worked on for only a short time, the technical results and scientific accomplishments were significant and could prove to be enabling technology in the disruptive advancement of the microelectronic photovoltaics industry.

  7. Photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Groth, H.

    1982-11-01

    The utilization of photovoltaic generators in measuring and signalling installations, communication systems, water pumping, and electric power plants is discussed. The advantages of solar generators over conventional power supply equipment are outlined.

  8. Snack, Facts

    ERIC Educational Resources Information Center

    Smith, Suzanne M.

    2005-01-01

    The American diet has undergone substantial changes, a fact that has negatively impacted the dental health of children. Primary prevention is the ideal method to address the current increased incidence of tooth decay. Educating kids, and their parents, about the qualities of snacks as well as the role of frequency of snacking could help to reduce…

  9. Reptile Facts.

    ERIC Educational Resources Information Center

    Steinheimer, Margaret

    1993-01-01

    Describes an award-winning bulletin board for introducing a unit on reptiles. This interactive bulletin board contains fun facts and counters common misconceptions about reptiles. Twelve true-false statements are hidden behind pull-up flaps. Four pictures ask students to identify the difference between often-confused animals. (PR)

  10. Microelectrode arrays in combination with in vitro models of spinal cord injury as tools to investigate pathological changes in network activity: facts and promises

    PubMed Central

    Mladinic, Miranda; Nistri, Andrea

    2013-01-01

    Microelectrode arrays (MEAs) represent an important tool to study the basic characteristics of spinal networks that control locomotion in physiological conditions. Fundamental properties of this neuronal rhythmicity like burst origin, propagation, coordination, and resilience can, thus, be investigated at multiple sites within a certain spinal topography and neighboring circuits. A novel challenge will be to apply this technology to unveil the mechanisms underlying pathological processes evoked by spinal cord injury (SCI). To achieve this goal, it is necessary to fully identify spinal networks that make up the locomotor central pattern generator (CPG) and to understand their operational rules. In this review, the use of isolated spinal cord preparations from rodents, or organotypic spinal slice cultures is discussed to study rhythmic activity. In particular, this review surveys our recently developed in vitro models of SCI by evoking excitotoxic (or even hypoxic/dysmetabolic) damage to spinal networks and assessing the impact on rhythmic activity and cell survival. These pathological processes which evolve via different cell death mechanisms are discussed as a paradigm to apply MEA recording for detailed mapping of the functional damage and its time-dependent evolution. PMID:23459694

  11. Microelectrode arrays in combination with in vitro models of spinal cord injury as tools to investigate pathological changes in network activity: facts and promises.

    PubMed

    Mladinic, Miranda; Nistri, Andrea

    2013-01-01

    Microelectrode arrays (MEAs) represent an important tool to study the basic characteristics of spinal networks that control locomotion in physiological conditions. Fundamental properties of this neuronal rhythmicity like burst origin, propagation, coordination, and resilience can, thus, be investigated at multiple sites within a certain spinal topography and neighboring circuits. A novel challenge will be to apply this technology to unveil the mechanisms underlying pathological processes evoked by spinal cord injury (SCI). To achieve this goal, it is necessary to fully identify spinal networks that make up the locomotor central pattern generator (CPG) and to understand their operational rules. In this review, the use of isolated spinal cord preparations from rodents, or organotypic spinal slice cultures is discussed to study rhythmic activity. In particular, this review surveys our recently developed in vitro models of SCI by evoking excitotoxic (or even hypoxic/dysmetabolic) damage to spinal networks and assessing the impact on rhythmic activity and cell survival. These pathological processes which evolve via different cell death mechanisms are discussed as a paradigm to apply MEA recording for detailed mapping of the functional damage and its time-dependent evolution. PMID:23459694

  12. Red facts: Ethylene. Fact sheet

    SciTech Connect

    Not Available

    1992-09-01

    EPA is directed by the Federal Insecticide, Fungicide, and Rodenticide Act as amended in 1988 (FIFRA '88) to review all pesticide products containing active ingredients initially registered before November 1, 1984, and to reregister those products that have a substantially complete data base and do not pose unreasonable adverse effects to people or the environment. The pesticide reregistration program is to be completed by the late 1990's. The RED FACTS fact sheet summarizes EPA's conclusion, as set forth in the Reregistration Eligibility Document (or RED), that products containing a pesticide do not pose unreasonable risks when used as directed by Agency-approved labeling, and are eligible for reregistration.

  13. Integrating Residential Photovoltaics With Power Lines

    NASA Technical Reports Server (NTRS)

    Borden, C. S.

    1985-01-01

    Report finds rooftop solar-cell arrays feed excess power to electric-utility grid for fee are potentially attractive large-scale application of photovoltaic technology. Presents assessment of breakeven costs of these arrays under variety of technological and economic assumptions.

  14. Facts First

    SciTech Connect

    Wiley, H. S.

    2009-02-01

    I enjoy reading online news and opinions not only because of convenience, but also because of the responses from the readers. I know that these responses tend to be biased towards the extremes of opinions, but it is always interesting to see the diverse reactions from even seemingly non-controversial subjects. A recent example was the response to an editorial by Richard Gallaghar (October, 2008) that proffered the seemingly obvious opinion that science students need a strong understanding of scientific history and philosophy to help them face future challenges. This provoked a response from a reader, a college professor, that a major reason for the lack of good university science education was the laziness of his colleagues. They were taking the “easy way out” by concentrating on teaching facts rather than scientific concepts. In the respondent’s viewpoint, it was far better to teach students how to think. Facts could always be looked up in textbooks. If you did not understand how to think critically and create knowledge, you could not be considered educated. Although I am very sympathetic to this point of view, I don’t believe that laziness is the reason why students are flooded with facts rather than concepts in biology class.

  15. Europe's space photovoltaics programme

    NASA Technical Reports Server (NTRS)

    Bogus, Klaus P.

    1994-01-01

    The current space PV (photovoltaic) technology development program of ESA is described. The program is closely coupled to the European space mission scenario for the next 10 year period and has as its main objective to make the most effective use of the limited resources available for technology in the present economical climate. This requires a well-balanced approach between concentration on very few options and keeping the competition alive if more than one promising technology exists. The paper describes ESA's main activities in the areas of solar array technology, solar cell technology, solar cell assembly technology, and special test and verification activities including the in-orbit demonstration of new technologies.

  16. Economic and financial analysis of residential photovoltaic systems. The impact of solar photovoltaics on utilities

    NASA Astrophysics Data System (ADS)

    Katzman, M. T.; Katzman, A. C.

    1982-02-01

    Hourly load data from El Paso Electric and Boston Edison are subjected to preliminary examination by comparison with simulated photovoltaic array output. Three utility production costing and reliability models are compared: SYSGEN, SIMSTOR, and GENCOST. All simulations suggest that photovoltaic penetration will: (1) result in economically significant fuel savings; (2) result in small reductions in capacity requirements; (3) result in total savings that are likely to exceed the costs of photovoltaic systems by the late 1980s. The value of savings per MW of photovoltaics diminishes with increased penetration.

  17. MOD silver metallization for photovoltaics

    NASA Technical Reports Server (NTRS)

    Vest, G. M.; Vest, R. W.

    1984-01-01

    The development of flat plate solar arrays is reported. Photovoltaic cells require back side metallization and a collector grid system on the front surface. Metallo-organic decomposition (MOD) silver films can eliminate most of the present problems with silver conductors. The objectives are to: (1) identify and characterize suitable MO compounds; (2) develop generic synthesis procedures for the MO compounds; (3) develop generic fabrication procedures to screen printable MOD silver inks; (4) optimize processing conditions to produce grid patterns and photovoltaic cells; and (5) develop a model which describes the adhesion between the fired silver film and the silicon surface.

  18. Photovoltaic systems sizing for Algeria

    SciTech Connect

    Arab, A.H.; Driss, B.A.; Amimeur, R.; Lorenzo, E.

    1995-02-01

    The purpose of this work is to develop an optimization method applicable to stand-alone photovoltaic systems as a function of its reliability. For a given loss-of-load probability (LLP), there are many combinations of battery capacity and photovoltaic array peak power. The problem consists in determining the couple which corresponds to a minimum total system cost. The method has been applied to various areas all over Algeria taking into account various climatic zones. The parameter used to define the different climatic zones is the clearness index KT for all the considered sites. The period of the simulation system is 10 years. 5 refs., 4 figs., 5 tabs.

  19. Magnetic field survey at PG&E photovoltaic sites

    SciTech Connect

    Chang, G.J.; Jennings, C.

    1994-08-01

    Public awareness has aroused concerns over the possible effects of magnetic fields on human health. While research continues to determine if magnetic fields do, in fact, affect human health, concerned individuals are requesting data on magnetic field sources in their environments to base personal decisions about limiting their exposure to these sources. Timely acceptance and implementation of photovoltaics (PV), particularly for distributed applications such as PV rooftops, windows, and vehicles, may be hampered by the lack of PV magnetic field data. To address this situation, magnetic flux density was measured around equipment at two PVUSA (Photovoltaics for Utility Scale Applications) project sites in Kerman and Davis, California. This report documents the data and compares the PV magnetic fields with published data on more prevalent magnetic field sources. Although not comprehensive, electric and magnetic field (EMF) data taken at PVUSA indicate that 60-Hz magnetic fields (the EMF type of greatest public concern) are significantly less for PV arrays than for household applications. Therefore, given the present EMF research knowledge, PV array EMF may not merit considerable concern. The PV system components exhibiting significant AC magnetic fields are the transformers and power conditioning units (PCUs). However, the AC magnetic fields associated with these components are localized and are not detected at PV system perimeters. Concern about transformer and PCU EMF would apply to several generation and storage technologies.

  20. Polycrystalline Thin-Film Research: Cadmium Telluride (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet that includes scope, core competencies and capabilities, and contact/web information for Polycrystalline Thin-Film Research: Cadmium Telluride at the National Center for Photovoltaics.

  1. Process Technology and Advanced Concepts: Organic Solar Cells (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet for the National Center for Photovoltaics: Process Technology and Advanced Concepts: Organic Solar Cell that includes scope, core competencies and capabilities, and contact/web information.

  2. Measurements and Characterization: Cell and Module Performance (Fact Sheet)

    SciTech Connect

    Not Available

    2011-02-01

    Capabilities fact sheet for the National Center for Photovoltaics: Measurements and Characterization -- Cell and Module Performance. One-sided sheet that includes Scope, Core Competencies and Capabilities, and Contact/Web information.

  3. Energy Systems Integration: NREL + Advanced Energy (Fact Sheet)

    SciTech Connect

    Not Available

    2015-02-01

    This fact sheet describes the collaboration between NREL and Advanced Energy Industries at the ESIF to test its advanced photovoltaic inverter technology with the ESIF's power hardware-in-the-loop system and megawatt-scale grid simulators.

  4. Photovoltaic Engineering

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The Ohio Aerospace Institute through David Scheiman and Phillip Jenkins provided the Photovoltaics Branch at the NASA Glenn Research Center (GRC) with expertise in photovoltaic (PV) research, flight experiments and solar cell calibration. NASA GRC maintains the only world-class solar cell calibration and measurement facility within NASA. GRC also has a leadership role within the solar cell calibration community, and is leading the effort to develop ISO standards for solar cell calibration. OAI scientists working under this grant provided much of the expertise and leadership in this area.

  5. Photovoltaic module mounting system

    SciTech Connect

    Miros, Robert H. J.; Mittan, Margaret Birmingham; Seery, Martin N; Holland, Rodney H

    2012-09-18

    A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

  6. Photovoltaic module mounting system

    SciTech Connect

    Miros, Robert H. J.; Mittan, Margaret Birmingham; Seery, Martin N.; Holland, Rodney H.

    2012-04-17

    A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

  7. Quo Vadis photovoltaics 2011

    NASA Astrophysics Data System (ADS)

    Jäger-Waldau, A.

    2011-10-01

    Since more than 10 years photovoltaics is one of the most dynamic industries with growth rates well beyond 40% per annum. This growth is driven not only by the progress in materials knowledge and processing technology, but also by market introduction programmes in many countries around the world. Despite the negative impacts on the economy by the financial crisis since 2009, photovoltaics is still growing at an extraordinary pace and had in 2010 an extraordinary success, as both production and markets doubled. The open question is what will happen in 2011 and the years after as the situation is dominated by huge manufacturing overcapacities and an increasing unpredictability of policy support. How can the PV industry continue their cost reduction to ensure another 10 to 20 years of sustained and strong growth necessary to make PV to one of the main pillars of a sustainable energy supply in 2030. Despite the fact, that globally the share of electricity from photovoltaic systems is still small, at local level it can be already now above 30% of the demand at certain times of the year. Future research in PV has to provide intelligent solutions not only on the solar cell alone, but also on the module and the system integration level in order to permit a 5 to 10% share of electricity in 2020.

  8. Energy Systems Integration: NREL + Google (Fact Sheet)

    SciTech Connect

    Not Available

    2015-02-01

    This fact sheet describes the collaboration between NREL, Google, and the IEEE Power Electronics Society at the ESIF to work on the Little Box Challenge, an open competition challenging engineers to build smaller power inverters for use in photovoltaic power systems.

  9. Red facts: Dibromodicyanobutane. Fact sheet

    SciTech Connect

    1996-06-01

    This fact sheet summarizes the information in the RED document for reregistration case 2780, dibromodicyanobutane. Dibromodicyanobutane (1,2-dibromo-2,4-dicyanobutane) is a microbiocide/microbiostat used to control slime-forming bacteria and fungi in commercial/industrial water cooling systems (recirculating), oil recovery drilling muds/packer fluids, pulp/paper mill water systems, secondary oil recovery rejection water, industrial adhesives and coatings, resin/latex/polymer emulsions, metalworking cutting fluids, paints, specialty industrial products (including fiber processing fluids, waxes, polishes, and inks), and wet-end additives/industrial processing chemicals.

  10. Photovoltaic cell

    SciTech Connect

    Bronstein-Bonte, I.Y.; Fischer, A.B.

    1986-12-16

    This patent describes a product comprising a photovoltaic cell including a luminescent dye which will absorb radiation at a wavelength to which the cell is not significantly responsive and emit radiation at a higher wavelength at which it is responsive. The improvement described here is wherein the dye comprises a lepidopterene.

  11. Photovoltaic energy

    NASA Astrophysics Data System (ADS)

    1990-01-01

    In 1989, the U.S. photovoltaic industry enjoyed a growth rate of 30 percent in sales for the second year in a row. This sends a message that the way we think about electricity is changing. Instead of big energy projects that perpetuate environmental and economic damage, there is a growing trend toward small renewable technologies that are well matched to end-user needs and operating conditions. As demand grows and markets expand, investment capital will be drawn to the industry and new growth trends will emerge. The photovoltaic industry around the world achieved record shipments also. Worldwide shipments of photovoltaic (PV) modules for 1989 totaled more than 40 megawatts (MW), nearly a 20 percent increase over last year's shipments. The previous two years showed increases in worldwide shipments of 23 and 25 percent, respectively. If this growth rate continues through the 1990s, as industry back orders would indicate, 300 to 1000 MW of PV-supplied power could be on line by 2000. Photovoltaic systems have low environmental impact and they are inexpensive to operate and maintain. Using solid-state technology, PV systems directly convert sunlight to electricity without high-temperature fluids or moving parts that could cause mechanical failure. This makes the technology very reliable.

  12. Double-layer electrode based on TiO2 nanotubes arrays for enhancing photovoltaic properties in dye-sensitized solar cells.

    PubMed

    He, Zuoli; Que, Wenxiu; Sun, Peng; Ren, Jiangbo

    2013-12-26

    The present work reports a rapid and facile method to fabricate a novel double-layer TiO2 photoanode, which is based on highly ordered TiO2 nanotube arrays and monodispersive scattering microspheres. This double-layer TiO2 sphere/TNTA photoanode have got many unique structural and optical properties from TiO2 scattering microspheres, such as high specific surface area, multiple interparticle scattering, and efficient light-harvesting. Results indicate that this as-fabricated double-layer TiO2 sphere/TNTA front-illumination dye-sensitized solar cell, which is fabricated from the TiO2 nanotube arrays with a 17.4 μm length after TiCl4 treatment, exhibits a pronounced power conversion efficiency of 7.24% under an AM1.5 G irradiation, which can be attributed to the increased incident photon-to-current conversion and light-harvesting efficiency. PMID:24304127

  13. Space Photovoltaic Research and Technology Conference

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Eleventh Space Photovoltaic Research and Technology conference was held at NASA Lewis Research Center from May 7 to 9, 1991. The papers and workshop summaries presented here report remarkable progress on a wide variety of approaches in space photovoltaics, both near and far term applications. Papers were presented in a variety of technical areas, including multijunction cell technology, GaAs and InP cells, system studies, cell and array development, and photovoltaics for conversion of laser radiation. Three workshops were held to discuss thin film cell development, III-V cell development, and space environmental effects.

  14. Assembly, physics, and application of highly electronic-type purified semiconducting carbon nanotubes in aligned array field effect transistors and photovoltaics

    NASA Astrophysics Data System (ADS)

    Arnold, Michael

    2015-03-01

    Recent advances in (1) achieving highly monodisperse semiconducting carbon nanotubes without problematic metallic nanotubes and (2) depositing these nanotubes into useful, organized arrays and assemblies on substrates have created new opportunities for studying the physics of these one-dimensional conductors and for applying them in electronics and photonics technologies. In this talk, I will present on two topics that are along these lines. In the first, we have pioneered a scalable approach for depositing aligned arrays of ultrahigh purity semiconducting SWCNTs (prepared using polyfluorene-derivatives) called floating evaporative self-assembly (FESA). FESA is exploited to create FETs with exceptionally high combined on-conductance and on-off ratio of 261 μS/ μm and 2 x105, respectively, for a channel length of 240 nm. This is 1400 x greater on-off ratio than SWCNT FETs fabricated by other methods, at comparable on-conductance per width of 250 μS/ μm, and 30-100 x greater on-conductance per width, at comparable on-off ratio of 105-107. In the second, we have discovered how to efficiently harvest photons using semiconducting SWCNTs by driving the dissociation of excitons using donor/acceptor heterojunctions. The flow of energy in SWCNT films occurs across a complex energy landscape, temporally resolved using two-dimensional white light ultrafast spectroscopy. We have demonstrated simple solar cells driven by SWCNT excitons, based on bilayers between C60 and ultrathin (5 nm) films of SWCNTs that achieve a 1% solar power conversion efficiency (7% at the bandgap). High internal quantum efficiency indicates that future blended or multijunction cells exploiting multiple layers will be many times more efficient.

  15. Photovoltaic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Loudin, James; Mathieson, Keith; Kamins, Ted; Wang, Lele; Galambos, Ludwig; Huie, Philip; Sher, Alexander; Harris, James; Palanker, Daniel

    2011-03-01

    Electronic retinal prostheses seek to restore sight to patients suffering from retinal degenerative disorders. Implanted electrode arrays apply patterned electrical stimulation to surviving retinal neurons, producing visual sensations. All current designs employ inductively coupled coils to transmit power and/or data to the implant. We present here the design and initial testing of a photovoltaic retinal prosthesis fabricated with a pixel density of up to 177 pixels/mm2. Photodiodes within each pixel of the subretinal array directly convert light to stimulation current, avoiding the use of bulky coil implants, decoding electronics, and wiring, and thereby reducing surgical complexity. A goggles-mounted camera captures the visual scene and transmits the data stream to a pocket processor. The resulting images are projected into the eyes by video goggles using pulsed, near infrared (~900 nm) light. Prostheses with three pixel densities (15, 55, and 177 pix/mm2) are being fabricated, and tests indicate a charge injection limit of 1.62 mC/cm2 at 25Hz. In vitro tests of the photovoltaic retinal stimulation using a 512-element microelectrode array have recorded stimulated spikes from the ganglion cells, with latencies in the 1-100ms range, and with peak irradiance stimulation thresholds varying from 0.1 to 1 mW/mm2. With 1ms pulses at 25Hz the average irradiance is more than 100 times below the IR retinal safety limit. Elicited retinal response disappeared upon the addition of synaptic blockers, indicating that the inner retina is stimulated rather than the ganglion cells directly, and raising hopes that the prosthesis will preserve some of the retina's natural signal processing.

  16. Photovoltaic System Performance

    1989-09-25

    PVFORM4.0 is used to design a photovoltaic (PV) system using a set of design parameters which optimize the system's economic potential for the proposed location and the expected operating conditions. PVFORM3.3 has been used to determine PV system size and optimum mounting configuration. The anticipated electrical load determines the system size and the weather and the mounting configuration affect the system output. PVFORM4.0 uses program-supplied default values or their user-supplied equivalents for each of amore » large number of parameters describing the system and time-series data describing the environment to perform a series of hourly calculations to simulate the physical (photovoltaic) performance of a PV system for a one-year period. These iterative calculations sample the performance of the PV system throughout a simulated 365-day year of system operation. Within any simulated day on which system performance is sampled, the calculations are done hourly. The number of days sampled and the interval between them is determined by an input parameter. The results of these calculations are summarized on a monthly basis in output tables and an optional plot file. The program is applicable to grid interactive or stand-alone flat-plate systems. The grid interactive system is assumed to use power purchased from a local utility to supply that portion of the load not met by the simulated PV array. If the array produces more energy than can be consumed by the load, the excess energy is assumed to be sold back to the utility at a constant energy sellback price. If a stand-alone system is being modeled, the program assumes that all energy produced by the simulated PV array is first applied to the external load, and any excess is then used to charge the battery bank. Energy not consumed by the load or the batteries is considered to be wasted.« less

  17. Future trends in space photovoltaics

    NASA Astrophysics Data System (ADS)

    Gledhill, Kristen; Marvin, Dean

    1994-12-01

    The Air Force, NASA, NRL and the commercial sector are all using small spacecraft to a greater extent in order to provide more cost-effective access to space. This paper discusses the generic photovoltaic technologies which are being studied and/or developed to support these smaller spacecraft, and identifies several specific examples. The unique requirements of these mission types include lower power arrays, arrays with lower mass and stowed volume which will be more compatible with small launch vehicles, and power systems with lower fabrication costs.

  18. Thin-Film Silicon Photovoltaics: Characterization of Thin-Film Deposition and Analysis of Enhanced Light Trapping from Scattering Nanoparticle Arrays

    NASA Astrophysics Data System (ADS)

    Langeland, Krista S.

    Thin-film solar cells have the potential to significantly decrease the cost of a finished device by cutting materials cost, and the characteristics of carrier transport through a thin film can concurrently increase the device performance over that of a wafer-based cell while tolerating a higher defect density in the absorbing material. However, while silicon is an attractive material for use in solar cells due to its nearly ideal band gap for single-junction cells and its relative abundance, its inefficient absorption of infrared light necessitates the development of light-trapping techniques to avoid losses in current generation. This thesis research has focused on two important goals: the development of a scalable thin-film silicon deposition method that produces high-quality material at minimal cost, and the evaluation of light-trapping mechanisms that will increase photon absorption in these films. Hot-wire chemical vapor deposition is used to fabricate silicon thin films with high crystalline fractions even on inexpensive substrates, and films grown with appropriate growth conditions exhibit initial open-circuit voltages above 450 mV, and while challenges in passivation still exist, this research illustrates the potential of this highly scalable and inexpensive deposition technique. Silver and silicon subwavelength structures were then both fabricated and simulated on ultra-thin silicon films on SiO2 to evaluate their potential for increasing light absorption through plasmonic and physical scattering mechanisms, and spectral response measurements demonstrate over a ten-fold increase in carrier generation with a metal nanoparticle surface array. Periodic dielectric structures exhibit Bloch modes in both measurement and simulation, with an increase in overall quantum efficiency of over 11% from both a flat silicon layer and one that is randomly textured. These results highlight the significant role of scattering particle distribution in determining the light

  19. Photovoltaic Plasma Interaction Test 2

    NASA Technical Reports Server (NTRS)

    Kaufman, Bradford A.; Chrulski, Daniel; Myers, Roger M.

    1996-01-01

    The International Space Station (ISS) program is developing a plasma contactor to mitigate the harmful effects of charge collection on the station's large photovoltaic arrays. The purpose of the present test was to examine the effects of charge collection on the solar array electrical circuit and to verify the effectiveness of the plasma contactor. The results showed that the plasma contactor was able to eliminate structure arcing for any array output voltage. However, the current requirements of the plasma contactor were higher than those for prior testing and predicted by analysis. Three possible causes for this excess current demand are discussed. The most likely appeared to be a high local pressure on or very near the surface of the array as a result of vacuum tank conditions. Therefore, in actual space conditions, the plasma contactor should work as predicted.

  20. J. F. Long experimental photovoltaic house

    NASA Astrophysics Data System (ADS)

    1982-06-01

    A photovoltaic system was installed and monitored for one year at a three-bedroom, two-bath residence located in the suburbs of Phoenix, Arizona. The roof consists of 120 solar modules divided into five sub-arrays. The output is converted to ac and the system is grid-connected. The performance of the system overall, of the photovoltaic arrays, inverter, utility interface, and data acquisition system were measured and discussed. Public acceptance of the system is also discussed. The system is illustrated, and performance data are extensively tabulated and graphed.

  1. NASA-OAST program in photovoltaic energy conversion

    NASA Technical Reports Server (NTRS)

    Mullin, J. P.; Flood, D. J.

    1982-01-01

    The NASA program in photovoltaic energy conversion includes research and technology development efforts on solar cells, blankets, and arrays. The overall objectives are to increase conversion efficiency, reduce mass, reduce cost, and increase operating life. The potential growth of space power requirements in the future presents a major challenge to the current state of technology in space photovoltaic systems.

  2. Performance characteristics of a combination solar photovoltaic heat engine energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  3. Approaches to Future Generation Photovoltaics and Solar Fuels: Multiple Exciton Generation in Quantum Dots, Quantum Dot Arrays, Molecular Singlet Fission, and Quantum Dot Solar Cells

    SciTech Connect

    Nozik, A. J.; Beard, M. C.; Johnson, J. C.; Hanna, M. C.; Luther, J. M.; Midgett, A.; Semonin, O.; Michel, J.

    2012-01-01

    One potential, long-term approach to more efficient future generation solar cells is to utilize the unique properties of quantum dots (QDs) and unique molecular chromophores to control the relaxation pathways of excited states to produce enhanced conversion efficiency through efficient multiple electron-hole pair generation from single photons . We have observed efficient multiple exciton generation (MEG) in PbSe, PbS, PbTe, and Si QDs and efficient singlet fission (SF) in molecules that satisfy specific requirements for their excited state energy level structure to achieve carrier multiplication. We have studied MEG in close-packed QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies in the 3-5% range via both nanocrystalline Schottky junctions and nanocrystalline p-n junctions. These solar cells also show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy. We have also observed very efficient SF in thin films of molecular crystals of 1,3 diphenylisobenzofuran with quantum yields of 200% at the optimum SF threshold of 2Eg (HOMO-LUMO for S{sub 0}-S{sub 1}), reflecting the creation of two excited triplet states from the first excited singlet state. Various possible configurations for novel solar cells based on MEG in QDs and SF in molecules that could produce high conversion efficiencies will be presented, along with progress in developing such new types of solar cells. Recent analyses of the effect of MEG or SF combined with solar concentration on the conversion efficiency of solar cells will be discussed.

  4. Mir Cooperative Solar Array

    NASA Technical Reports Server (NTRS)

    Skor, Mike; Hoffman, Dave J.

    1997-01-01

    The Mir Cooperative Solar Array (MCSA), produced jointly by the United States and Russia, was deployed on the Mir Russian space station on May 25, 1996. The MCSA is a photovoltaic electrical power system that can generate up to 6 kW. The power from the MCSA is needed to extend Mir's lifetime and to support experiments conducted there by visiting U.S. astronauts. The MCSA was brought to Mir via the Space Shuttle Atlantis on the STS-74 mission, launched November 12, 1995. This cooperative venture combined the best technology of both countries: the United States provided high-efficiency, lightweight photovoltaic panel modules, whereas Russia provided the array structure and deployment mechanism. Technology developed in the Space Station Freedom Program, and now being used in the International Space Station, was used to develop MCSA's photovoltaic panel. Performance data obtained from MCSA operation on Mir will help engineers better understand the performance of the photovoltaic panel modules in orbit. This information will be used to more accurately predict the performance of the International Space Station solar arrays. Managed by the NASA Lewis Research Center for NASA's International Space Station Program Office in Houston, Texas, the MCSA Project was completed on time and under budget despite a very aggressive schedule.

  5. Photovoltaic receivers for laser beamed power in space

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    1991-01-01

    There has recently been a resurgence of interest in the use of beamed power to support space exploration activities. One of the most promising beamed power concepts uses a laser beam to transmit power to a remote photovoltaic array. Large lasers can be located on cloud-free sites at one or more ground locations and illuminate solar arrays to a level sufficient to provide operating power. Issues involved in providing photovoltaic receivers for such applications are discussed.

  6. Stand-alone photovoltaic (PV) powered electrochromic window

    DOEpatents

    Benson, David K.; Crandall, Richard S.; Deb, Satyendra K.; Stone, Jack L.

    1995-01-01

    A variable transmittance double pane window includes an electrochromic material that has been deposited on one pane of the window in conjunction with an array of photovoltaic cells deposited along an edge of the pane to produce the required electric power necessary to vary the effective transmittance of the window. A battery is placed in a parallel fashion to the array of photovoltaic cells to allow the user the ability to manually override the system when a desired transmittance is desired.

  7. Stand-alone photovoltaic (PV) powered electrochromic window

    DOEpatents

    Benson, D.K.; Crandall, R.S.; Deb, S.K.; Stone, J.L.

    1995-01-24

    A variable transmittance double pane window includes an electrochromic material that has been deposited on one pane of the window in conjunction with an array of photovoltaic cells deposited along an edge of the pane to produce the required electric power necessary to vary the effective transmittance of the window. A battery is placed in a parallel fashion to the array of photovoltaic cells to allow the user the ability to manually override the system when a desired transmittance is desired. 11 figures.

  8. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Krebs, Frederik C.; Chen, Hongzheng

    2013-12-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year's supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency of organic photovoltaic systems, while maintaining the inherent material, economic and fabrication benefits, has absorbed a great deal of research attention in recent years. Here significant progress has been made with reports now of organic photovoltaic devices with efficiencies of around 10%. Yet operating effectively across the electromagnetic spectrum remains a challenge. 'The trend is towards engineering low bandgap polymers with a wide optical absorption range and efficient hole/electron transport materials, so that light harvesting in the red and infrared region is enhanced and as much light of the solar spectrum as possible can be converted into an electrical current', explains Mukundan Thelakkat and colleagues in Germany, the US and UK. In this special issue they report on how charge carrier mobility and morphology of the active blend layer in thin film organic solar cells correlate with device parameters [2]. The work contributes to a better understanding of the solar-cell characteristics of polymer:fullerene blends, which form the material basis for some of the most

  9. Laser photovoltaic power system synergy for SEI applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Hickman, J. M.

    1991-01-01

    Solar arrays can provide reliable space power, but do not operate when there is no solar energy. Photovoltaic arrays can also convert laser energy with high efficiency. One proposal to reduce the required mass of energy storage required is to illuminate the photovoltaic arrays by a ground laser system. It is proposed to locate large lasers on cloud-free sites at one or more ground locations, and use large lenses or mirrors with adaptive optical correction to reduce the beam spread due to diffraction or atmospheric turbulence. During the eclipse periods or lunar night, the lasers illuminate the solar arrays to a level sufficient to provide operating power.

  10. Nanostructured photovoltaics

    NASA Astrophysics Data System (ADS)

    Fu, Lan; Tan, H. Hoe; Jagadish, Chennupati

    2013-01-01

    Energy and the environment are two of the most important global issues that we currently face. The development of clean and sustainable energy resources is essential to reduce greenhouse gas emission and meet our ever-increasing demand for energy. Over the last decade photovoltaics, as one of the leading technologies to meet these challenges, has seen a continuous increase in research, development and investment. Meanwhile, nanotechnology, which is considered to be the technology of the future, is gradually revolutionizing our everyday life through adaptation and incorporation into many traditional technologies, particularly energy-related technologies, such as photovoltaics. While the record for the highest efficiency is firmly held by multijunction III-V solar cells, there has never been a shortage of new research effort put into improving the efficiencies of all types of solar cells and making them more cost effective. In particular, there have been extensive and exciting developments in employing nanostructures; features with different low dimensionalities, such as quantum wells, nanowires, nanotubes, nanoparticles and quantum dots, have been incorporated into existing photovoltaic technologies to enhance their performance and/or reduce their cost. Investigations into light trapping using plasmonic nanostructures to effectively increase light absorption in various solar cells are also being rigorously pursued. In addition, nanotechnology provides researchers with great opportunities to explore the new ideas and physics offered by nanostructures to implement advanced solar cell concepts such as hot carrier, multi-exciton and intermediate band solar cells. This special issue of Journal of Physics D: Applied Physics contains selected papers on nanostructured photovoltaics written by researchers in their respective fields of expertise. These papers capture the current excitement, as well as addressing some open questions in the field, covering topics including the

  11. Space and Terrestrial Photovoltaics: Synergy and Diversity

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila; Raffaelle, Ryne; Emery, Keith

    2002-01-01

    terrestrial solar cell communities shall once again share many common goals and, in fact, companies may manufacture both space and terrestrial solar cells in III-V materials and thin film materials. Basic photovoltaics research including these current trends in nanotechnology provides a valuable service for both worlds in that fundamental understanding of cell processes is still vitally important, particularly with new materials or new cell structures. It is entirely possible that one day we might have one solar array design that will meet the criteria for success in both space and on the Earth or perhaps the Moon or Mars.

  12. NREL Center for Photovoltaics

    ScienceCinema

    None

    2016-07-12

    Solar cells, also called photovoltaics (PV) by solar cell scientists, convert sunlight directly into electricity. Solar cells are often used to power calculators and watches. The performance of a solar cell is measured in terms of its efficiency at turning sunlight into electricity. Only sunlight of certain energies will work efficiently to create electricity, and much of it is reflected or absorbed by the material that make up the cell. Because of this, a typical commercial solar cell has an efficiency of 15%—about one-sixth of the sunlight striking the cell generates electricity. Low efficiencies mean that larger arrays are needed, and that means higher cost. Improving solar cell efficiencies while holding down the cost per cell is an important goal of the PV industry, researchers at the National Renewable Energy Laboratory (NREL) and other U.S. Department of Energy (DOE) laboratories, and they have made significant progress. The first solar cells, built in the 1950s, had efficiencies of less than 4%. For a text version of this video visit http://www.nrel.gov/learning/re_photovoltaics_video_text.html

  13. NREL Center for Photovoltaics

    SciTech Connect

    2009-01-01

    Solar cells, also called photovoltaics (PV) by solar cell scientists, convert sunlight directly into electricity. Solar cells are often used to power calculators and watches. The performance of a solar cell is measured in terms of its efficiency at turning sunlight into electricity. Only sunlight of certain energies will work efficiently to create electricity, and much of it is reflected or absorbed by the material that make up the cell. Because of this, a typical commercial solar cell has an efficiency of 15%—about one-sixth of the sunlight striking the cell generates electricity. Low efficiencies mean that larger arrays are needed, and that means higher cost. Improving solar cell efficiencies while holding down the cost per cell is an important goal of the PV industry, researchers at the National Renewable Energy Laboratory (NREL) and other U.S. Department of Energy (DOE) laboratories, and they have made significant progress. The first solar cells, built in the 1950s, had efficiencies of less than 4%. For a text version of this video visit http://www.nrel.gov/learning/re_photovoltaics_video_text.html

  14. Microsystem enabled photovoltaic modules and systems

    DOEpatents

    Nielson, Gregory N; Sweatt, William C; Okandan, Murat

    2015-05-12

    A microsystem enabled photovoltaic (MEPV) module including: an absorber layer; a fixed optic layer coupled to the absorber layer; a translatable optic layer; a translation stage coupled between the fixed and translatable optic layers; and a motion processor electrically coupled to the translation stage to controls motion of the translatable optic layer relative to the fixed optic layer. The absorber layer includes an array of photovoltaic (PV) elements. The fixed optic layer includes an array of quasi-collimating (QC) micro-optical elements designed and arranged to couple incident radiation from an intermediate image formed by the translatable optic layer into one of the PV elements such that it is quasi-collimated. The translatable optic layer includes an array of focusing micro-optical elements corresponding to the QC micro-optical element array. Each focusing micro-optical element is designed to produce a quasi-telecentric intermediate image from substantially collimated radiation incident within a predetermined field of view.

  15. Reliability of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1986-01-01

    In order to assess the reliability of photovoltaic modules, four categories of known array failure and degradation mechanisms are discussed, and target reliability allocations have been developed within each category based on the available technology and the life-cycle-cost requirements of future large-scale terrestrial applications. Cell-level failure mechanisms associated with open-circuiting or short-circuiting of individual solar cells generally arise from cell cracking or the fatigue of cell-to-cell interconnects. Power degradation mechanisms considered include gradual power loss in cells, light-induced effects, and module optical degradation. Module-level failure mechanisms and life-limiting wear-out mechanisms are also explored.

  16. Microlens arrays

    NASA Astrophysics Data System (ADS)

    Hutley, Michael C.; Stevens, Richard F.; Daly, Daniel J.

    1992-04-01

    Microlenses have been with us for a long time as indeed the very word lens reminds us. Many early lenses,including those made by Hooke and Leeuwenhoek in the 17th century were small and resembled lentils. Many languages use the same word for both (French tilentillelt and German "Linse") and the connection is only obscure in English because we use the French word for the vegetable and the German for the optic. Many of the applications for arrays of inicrolenses are also well established. Lippmann's work on integral photography at the turn of the century required lens arrays and stimulated an interest that is very much alive today. At one stage, lens arrays played an important part in high speed photography and various schemes have been put forward to take advantage of the compact imaging properties of combinations of lens arrays. The fact that many of these ingenious schemes have not been developed to their full potential has to a large degree been due to the absence of lens arrays of a suitable quality and cost.

  17. Painkiller (Oxy, Vike) Facts

    MedlinePlus

    ... People Abuse Alcohol Facts Cigarette and Tobacco Facts Cocaine (Coke, Crack) Facts Heroin (Smack, Junk) Facts Marijuana ( ... these pills just like they sell heroin or cocaine. Some people borrow or steal these pills from ...

  18. Photovoltaics: New opportunities for utilities

    NASA Astrophysics Data System (ADS)

    1991-07-01

    This publication presents information on photovoltaics. The following topics are discussed: residential photovoltaics- the New England experience builds confidence in PV; Austin's 300-kW Photovoltaic Power Station- evaluating the breakeven costs; residential photovoltaics- the lessons learned; photovoltaics for electric utility use; least-cost planning- the environmental link; photovoltaics in the distribution system; photovoltaic systems for the rural consumer; the issues of utility-intertied photovoltaics; and photovoltaics for large-scale use- costs ready to drop again.

  19. Photovoltaics: New opportunities for utilities

    SciTech Connect

    Not Available

    1991-07-01

    This publication presents information on photovoltaics. The following topics are discussed: Residential Photovoltaics: The New England Experience Builds Confidence in PV; Austin's 300-kW Photovoltaic Power Station: Evaluating the Breakeven Costs; Residential Photovoltaics: The Lessons Learned; Photovoltaics for Electric Utility Use; Least-Cost Planning: The Environmental Link; Photovoltaics in the Distribution System; Photovoltaic Systems for the Rural Consumer; The Issues of Utility-Intertied Photovoltaics; and Photovoltaics for Large-Scale Use: Costs Ready to Drop Again.

  20. Photovoltaic solar concentrator

    SciTech Connect

    Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J.; Sanchez, Carlos Anthony; Clews, Peggy J.; Gupta, Vipin P.

    2015-09-08

    A process including forming a photovoltaic solar cell on a substrate, the photovoltaic solar cell comprising an anchor positioned between the photovoltaic solar cell and the substrate to suspend the photovoltaic solar cell from the substrate. A surface of the photovoltaic solar cell opposite the substrate is attached to a receiving substrate. The receiving substrate may be bonded to the photovoltaic solar cell using an adhesive force or a metal connecting member. The photovoltaic solar cell is then detached from the substrate by lifting the receiving substrate having the photovoltaic solar cell attached thereto and severing the anchor connecting the photovoltaic solar cell to the substrate. Depending upon the type of receiving substrate used, the photovoltaic solar cell may be removed from the receiving substrate or remain on the receiving substrate for use in the final product.

  1. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Krebs, Frederik C.; Chen, Hongzheng

    2013-12-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year's supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency of organic photovoltaic systems, while maintaining the inherent material, economic and fabrication benefits, has absorbed a great deal of research attention in recent years. Here significant progress has been made with reports now of organic photovoltaic devices with efficiencies of around 10%. Yet operating effectively across the electromagnetic spectrum remains a challenge. 'The trend is towards engineering low bandgap polymers with a wide optical absorption range and efficient hole/electron transport materials, so that light harvesting in the red and infrared region is enhanced and as much light of the solar spectrum as possible can be converted into an electrical current', explains Mukundan Thelakkat and colleagues in Germany, the US and UK. In this special issue they report on how charge carrier mobility and morphology of the active blend layer in thin film organic solar cells correlate with device parameters [2]. The work contributes to a better understanding of the solar-cell characteristics of polymer:fullerene blends, which form the material basis for some of the most

  2. Design considerations for Mars photovoltaic power systems

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Appelbaum, Joseph

    1990-01-01

    Considerations for operation of a photovoltaic power system on Mars are discussed with reference to Viking Lander data. The average solar insolation at Mars is 590 W/sq m, which is reduced yet further by atmospheric dust. Of major concern are dust storms, which have been observed to occur on local as well as on global scales, and their effect on solar array output. While atmospheric opacity may rise to values ranging from 3 to 9, depending on storm severity, there is still an appreciable large diffuse illumination, even at high opacities, so that photovoltaic operation is still possible. If the power system is to continue to generate power even on high-optical-opacity (i.e., dusty atmosphere) days, it is important that the photovoltaic system be designed to collect diffuse irradiance as well as direct. Energy storage will be required for operation during the night. Temperature and wind provide additional considerations for array design.

  3. Space power technology 21: Photovoltaics

    NASA Technical Reports Server (NTRS)

    Wise, Joseph

    1989-01-01

    The Space Power needs for the 21st Century and the program in photovoltaics needed to achieve it are discussed. Workshops were conducted in eight different power disciplines involving industry and other government agencies. The Photovoltaics Workshop was conducted at Aerospace Corporation in June 1987. The major findings and recommended program from this workshop are discussed. The major finding is that a survivable solar power capability is needed in photovoltaics for critical Department of Defense missions including Air Force and Strategic Defense Initiative. The tasks needed to realize this capability are described in technical, not financial, terms. The second finding is the need for lightweight, moderately survivable planar solar arrays. High efficiency thin III-V solar cells can meet some of these requirements. Higher efficiency, longer life solar cells are needed for application to both future planar and concentrator arrays with usable life up to 10 years. Increasing threats are also anticipated and means for avoiding prolonged exposure, retraction, maneuvering and autonomous operation are discussed.

  4. Detailed Performance Model for Photovoltaic Systems: Preprint

    SciTech Connect

    Tian, H.; Mancilla-David, F.; Ellis, K.; Muljadi, E.; Jenkins, P.

    2012-07-01

    This paper presents a modified current-voltage relationship for the single diode model. The single-diode model has been derived from the well-known equivalent circuit for a single photovoltaic cell. The modification presented in this paper accounts for both parallel and series connections in an array.

  5. Photovoltaic Engineering Testbed Designed for Calibrating Photovoltaic Devices in Space

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2002-01-01

    Accurate prediction of the performance of solar arrays in space requires that the cells be tested in comparison with a space-flown standard. Recognizing that improvements in future solar cell technology will require an ever-increasing fidelity of standards, the Photovoltaics and Space Environment Branch at the NASA Glenn Research Center, in collaboration with the Ohio Aerospace Institute, designed a prototype facility to allow routine calibration, measurement, and qualification of solar cells on the International Space Station, and then the return of the cells to Earth for laboratory use. For solar cell testing, the Photovoltaic Engineering Testbed (PET) site provides a true air-mass-zero (AM0) solar spectrum. This allows solar cells to be accurately calibrated using the full spectrum of the Sun.

  6. The NASA photovoltaic technology program

    NASA Technical Reports Server (NTRS)

    Mullin, J. P.; Loria, J. C.; Brandhorst, H. W., Jr.

    1984-01-01

    The NASA Office of Aeronautical and Space Technology OAST Program in space photovoltaics is reviewed. From the perspective of national landmark mission requirements and five year and 25-year long range plans, the texture of the program is revealed. Planar silicon and concentrator GaAs array technology advances are discussed. Advances in lightweight (50 micro cell) arrays and radiation tolerance research are presented. Recent progress in cascade cells and ultralightweight GaAs planar cells is noted. Progress in raising silicon cell voltage to its theoretical maximum is detailed. Advanced concepts such as plasmon converters and the Long Duration Exposure Facility LDEF flight experiments pertaining to solar cell and array technology are also shown.

  7. Photovoltaic cell

    SciTech Connect

    Jordan, J.F.; Lampkin, C.M.

    1981-12-08

    A photovoltaic cell has: an electrically conductive substrate, which may be glass having a film of conductive tin oxide; a first layer containing a suitable semiconductor, which layer has a first component film with an amorphous structure and a second component film with a polycrystalline structure; a second layer forming a heterojunction with the first layer; and suitable electrodes where the heterojunction is formed from a solution containing copper, the amorphous film component is superposed above an electrically conductive substrate to resist permeation of the copper-containing material to shorting electrical contact with the substrate. The penetration resistant amporphous layer permits a variety of processes to be used in forming the heterojunction with even very thin layers (1-6 mu thick) of underlying polycrystalline semi-conductor materials. In some embodiments, the amorphous-like structure may be formed by the addition of aluminum or zirconium compounds to a solution of cadmium salts sprayed over a heated substrate.

  8. Performance degradation and cleaning of photovoltaic arrays

    NASA Astrophysics Data System (ADS)

    Sheskin, T. J.; Chang, G. C.; Cull, R. C.; Knapp, W. D.

    NASA tests results from an 18 mo program of cleaning silicone-encapsulated and glass fronted solar cell panels in urban and desert environments to examine the effects of cleaning on module performance are reported. The panels were cleaned on weekly, monthly, quarterly, or semi-annual basis, while other panels of the same construction were not cleaned and served as controls. Commercially-available detergents and city water were employed for the tests, and the measurements were maintained of the modules' continuing short-circuit current output. The decay of the output was determined by least square regression analyses. Performance degradation was noticeably less in glass covered, rather than silicone-encapsulated modules which decayed faster in urban than in desert environments. Lower frequency cleanings are recommended where labor costs are high.

  9. Performance degradation and cleaning of photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Sheskin, T. J.; Chang, G. C.; Cull, R. C.; Knapp, W. D.

    1982-01-01

    NASA tests results from an 18 mo program of cleaning silicone-encapsulated and glass fronted solar cell panels in urban and desert environments to examine the effects of cleaning on module performance are reported. The panels were cleaned on weekly, monthly, quarterly, or semi-annual basis, while other panels of the same construction were not cleaned and served as controls. Commercially-available detergents and city water were employed for the tests, and the measurements were maintained of the modules' continuing short-circuit current output. The decay of the output was determined by least square regression analyses. Performance degradation was noticeably less in glass covered, rather than silicone-encapsulated modules which decayed faster in urban than in desert environments. Lower frequency cleanings are recommended where labor costs are high.

  10. Portable thermo-photovoltaic power source

    DOEpatents

    Zuppero, Anthony C.; Krawetz, Barton; Barklund, C. Rodger; Seifert, Gary D.

    1997-01-14

    A miniature thermo-photovoltaic (TPV) device for generation of electrical power for use in portable electronic devices. A TPV power source is constructed to provide a heat source chemical reactor capable of using various fuels, such as liquid hydrocarbons, including but not limited to propane, LPG, butane, alcohols, oils and diesel fuels to generate a source of photons. A reflector dish guides misdirected photon energy from the photon source toward a photovoltaic array. A thin transparent protector sheet is disposed between the photon source and the array to reflect back thermal energy that cannot be converted to electricity, and protect the array from thermal damage. A microlens disposed between the protector sheet and the array further focuses the tailored band of photon energy from the photon source onto an array of photovoltaic cells, whereby the photon energy is converted to electrical power. A heat recuperator removes thermal energy from reactor chamber exhaust gases, preferably using mini- or micro-bellows to force air and fuel past the exhaust gases, and uses the energy to preheat the fuel and oxidant before it reaches the reactor, increasing system efficiency. Mini- or micro-bellows force ambient air through the system both to supply oxidant and to provide cooling. Finally, an insulator, which is preferably a super insulator, is disposed around the TPV power source to reduce fuel consumption, and to keep the TPV power source cool to the touch so it can be used in hand-held devices.

  11. Zika Virus Fact Sheet

    MedlinePlus

    ... 2014 Fact sheets Features Commentaries 2014 Multimedia Contacts Zika virus Fact sheet Updated 6 September 2016 Key facts ... and last for 2-7 days. Complications of Zika virus disease After a comprehensive review of evidence, there ...

  12. Diet myths and facts

    MedlinePlus

    Obesity - diet myths and facts; Overweight - diet myths and fact; Weight-loss diet myths and facts ... evidence: using the proposed effect of breakfast on obesity to show 2 practices that distort scientific evidence. ...

  13. Photovoltaic concentrator pointing dynamics and plasma interaction study

    SciTech Connect

    Stern, T.G.

    1984-01-01

    The objectives of this experiment are to use the Space Technology Experiments Platform (STEP) system to demonstrate the viability of concentrator photovoltaic arrays by: (1) configuring a deployable mast on the STEP pallet with concentrator mass models and some active photovoltaic modules (2) measuring the array pointing dynamics under normal rotation as well as disturbance conditions (3) performing an array plasma interaction experiment to determine the steady-state plasma losses under various voltage conditions and (4) providing active distributed control of the support truss to determine the improvement in dynamic response. Experiment approach and test control and instrumentation are described.

  14. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Osullivan, G.; Merrill, W. C.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. Optimization of the inverter/controller design is discussed as part of an overall photovoltaic power system designed for maximum energy extraction from the solar array. The special design requirements for the inverter/ controller include: a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy.

  15. Photovoltaic cell

    SciTech Connect

    Jordan, J. F.; Lampkin, C. M.

    1981-02-03

    A photovoltaic cell is disclosed having an electrically conductive substrate, which may be glass having a film of conductive tin oxide. A first layer contains a suitable semiconductor, which layer has a first component film with an amorphous structure and a second component film with a polycrystalline structure a second layer forms a heterojunction with the first layer suitable electrodes are provided where the heterojunction is formed from a solution containing copper, and the amorphous film component is superposed above an electrically conductive substrate to resist permeation of the copper-containing material to shorting electrical contact with the substrate. The penetration resistant amorphous layer permits a variety of processes to be used in forming the heterojunction with even very thin layers (1-6 mu thick) of underlying polycrystalline semi-conductor materials. In some embodiments, the amorphous-like structure may be formed by the addition of aluminum or zirconium compounds to a solution of cadmium salts sprayed over a heated substrate.

  16. Photovoltaics - Where are we going?

    NASA Technical Reports Server (NTRS)

    Callaghan, W. T.

    1984-01-01

    The directions that will be followed for solar cell development, production and marketing are projected on the basis of experiences gained during the JPL's Flat-Plate Solar Array project. It is thought that a billion dollar market for Si ribbons can be established by 1990. Thin film technology will yield a product at $2 U.S./W at the end of the 1980s. R&D is growing more focused on central station photovoltaic generators, although the residential market may be the more suitable goal. The intermediate markets, e.g., schools, hospitals and shopping centers may be developed before the central stations.

  17. Space Photovoltaic Research and Technology 1995

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey (Compiler)

    1995-01-01

    The Fourteenth Space Photovoltaic Research and Technology conference was held at the NASA Lewis Research Center from October 24-26, 1995. The abstracts presented in this volume report substantial progress in a variety of areas in space photovoltaics. Technical and review papers were presented in many areas, including high efficiency GaAs and InP solar cells, GaAs/Ge cells as commercial items, high efficiency multiple bandgap cells, solar cell and array technology, heteroepitaxial cells, thermophotovoltaic energy conversion, and space radiation effects. Space flight data on a variety of cells were also presented.

  18. Space Photovoltaic Research and Technology 1995

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey (Compiler)

    1996-01-01

    The Fourteenth Space Photovoltaic Research and Technology conference was held at the NASA Lewis Research Center from October 24-26, 1995. The abstracts presented in this volume report substantial progress in a variety of areas in space photovoltaics. Technical and review papers were presented in many areas, including high efficiency GaAs and InP solar cells, GaAs/Ge cells as commercial items, high efficiency multiple bandgap cells, solar cell and array technology, heteroepitaxial cells, thermophotovoltaic energy conversion, and space radiation effects. Space flight data on a variety of cells were also presented.

  19. Photovoltaic device and method

    DOEpatents

    Cleereman, Robert J; Lesniak, Michael J; Keenihan, James R; Langmaid, Joe A; Gaston, Ryan; Eurich, Gerald K; Boven, Michelle L

    2015-01-27

    The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

  20. Photovoltaic device and method

    SciTech Connect

    Cleereman, Robert; Lesniak, Michael J.; Keenihan, James R.; Langmaid, Joe A.; Gaston, Ryan; Eurich, Gerald K.; Boven, Michelle L.

    2015-11-24

    The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

  1. Amorphous silicon photovoltaic devices

    DOEpatents

    Carlson, David E.; Lin, Guang H.; Ganguly, Gautam

    2004-08-31

    This invention is a photovoltaic device comprising an intrinsic or i-layer of amorphous silicon and where the photovoltaic device is more efficient at converting light energy to electric energy at high operating temperatures than at low operating temperatures. The photovoltaic devices of this invention are suitable for use in high temperature operating environments.

  2. Decentralized solar photovoltaic energy systems

    NASA Astrophysics Data System (ADS)

    Krupka, M. C.

    1980-09-01

    Emphasis was placed upon the selection and use of a model residential photovoltaic system to develop and quantify the necessary data. The model consists of a reference home located in Phoenix, AZ utilizing a unique solar cell array roof shingle combination. Silicon solar cells, rated at 13.5 percent efficiency at 28 C and 100 mW/sq cm insolation are used to generate 10 kW (peak). An all electric home is considered with lead acid battery storage, DC AC inversion and utility backup. The reference home is compared to others in regions of different insolation. It is suggested that solar cell materials production and fabrication may have the major environmental impact when comparing all facets of photovoltaic system usage. Fabrication of the various types of solar cell systems involves the need, handling, and transportation of many toxic and hazardous chemicals with attendant health and safety impacts. Increases in production of such materials as lead, antimony, sulfuric acid, copper, plastics, cadmium and gallium will be required should large scale usage of photovoltaic systems be implemented.

  3. Polycrystalline Thin-Film Research: Copper Indium Gallium Diselenide (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet for the National Center for Photovoltaics: Polycrystalline Thin-Film Research: Copper Indium Gallium Diselenide that includes scope, core competencies and capabilities, and contact/web information.

  4. NREL Policy Stacking Theory Correlates Key Indicators with Solar Market Success (Fact Sheet)

    SciTech Connect

    Not Available

    2014-11-01

    NREL's Integrated Applications Group evaluated the time-dependent relationships between policy implementation and the success of solar markets using historical data for installed capacity of solar photovoltaic energy systems. This Science and Technology Highlights fact sheet summarizes their research.

  5. Advanced Process Technology: Combi Materials Science and Atmospheric Processing (Fact Sheet)

    SciTech Connect

    Not Available

    2011-06-01

    Capabilities fact sheet for the National Center for Photovoltaics: Process Technology and Advanced Concepts -- High-Throughput Combi Material Science and Atmospheric Processing that includes scope, core competencies and capabilities, and contact/web information.

  6. Transparent ultraviolet photovoltaic cells.

    PubMed

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future. PMID:26872163

  7. Transparent ultraviolet photovoltaic cells.

    PubMed

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  8. Autonomous photovoltaic-diesel power system design

    NASA Astrophysics Data System (ADS)

    Calloway, T. M.

    A methodology for designing an autonomous photovoltaic power system in conjunction with a diesel-fueled electric generator and a battery has been developed. Any photovoltaic array energy not utilized immediately by the load is stored in the battery bank. The diesel generator set is operated periodically at 14-day intervals to ensure its availability and occasionally as needed during winter to supplement combined output from the array and battery. It is hypothesized that logistical support is infrequent, so the hybrid photovoltaic-diesel power system is designed to consume only 10% as much fuel as would a diesel-only system. This constraint is used to generate a set of possible combinations of array area and battery energy storage capacity. For each combination, a battery-life model predicts the time interval between battery replacements by deducting the fraction of total life consumed each day. An economic model then produces life-cycle system cost. Repeating this process for different combinations of array area and battery capacity identifies the minimum-cost system design.

  9. Photovoltaic fibers

    NASA Astrophysics Data System (ADS)

    Gaudiana, Russell; Eckert, Robert; Cardone, John; Ryan, James; Montello, Alan

    2006-08-01

    It was realized early in the history of Konarka that the ability to produce fibers that generate power from solar energy could be applied to a wide variety of applications where fabrics are utilized currently. These applications include personal items such as jackets, shirts and hats, to architectural uses such as awnings, tents, large covers for cars, trucks and even doomed stadiums, to indoor furnishings such as window blinds, shades and drapes. They may also be used as small fabric patches or fiber bundles for powering or recharging batteries in small sensors. Power generating fabrics for clothing is of particular interest to the military where they would be used in uniforms and body armor where portable power is vital to field operations. In strong sunlight these power generating fabrics could be used as a primary source of energy, or they can be used in either direct sunlight or low light conditions to recharge batteries. Early in 2002, Konarka performed a series of proof-of-concept experiments to demonstrate the feasibility of building a photovoltaic cell using dye-sensitized titania and electrolyte on a metal wire core. The approach taken was based on the sequential coating processes used in making fiber optics, namely, a fiber core, e.g., a metal wire serving as the primary electrode, is passed through a series of vertically aligned coating cups. Each of the cups contains a coating fluid that has a specific function in the photocell. A second wire, used as the counter electrode, is brought into the process prior to entering the final coating cup. The latter contains a photopolymerizable, transparent cladding which hardens when passed through a UV chamber. Upon exiting the UV chamber, the finished PV fiber is spooled. Two hundred of foot lengths of PV fiber have been made using this process. When the fiber is exposed to visible radiation, it generates electrical power. The best efficiency exhibited by these fibers is 6% with an average value in the 4

  10. Photovoltaic Power for the Nanosat Project

    SciTech Connect

    Rose, B.H.

    1999-06-01

    This report describes the characteristics of photovoltaic arrays that maybe suitable for use with nanosatellite electronic systems. It includes a thorough literature search on power management and distribution systems for satellites as small as microsatellites. The major conclusion to be drawn is that it is the total system, including satellite electronic system, photovoltaic systems, peak power tracker and the power management and distribution systems which need to be optimized. An example of a peak power tracker is given, and a novel series connected boost unit is described which might allow the system voltage to be increased if enough photovoltaic panels to operate the systems in real time is impractical. Finally, it is recommended that the development effort be oriented and expanded to include a peak power tracker and other power management and distribution systems.

  11. Decentalized solar photovoltaic energy systems

    SciTech Connect

    Krupka, M. C.

    1980-09-01

    Environmental data for decentralized solar photovoltaic systems have been generated in support of the Technology Assessment of Solar Energy Systems program (TASE). Emphasis has been placed upon the selection and use of a model residential photovoltaic system to develop and quantify the necessary data. The model consists of a reference home located in Phoenix, AZ, utilizing a unique solar cell array-roof shingle combination. Silicon solar cells, rated at 13.5% efficiency at 28/sup 0/C and 100 mW/cm/sup 2/ (AMI) insolation are used to generate approx. 10 kW (peak). An all-electric home is considered with lead-acid battery storage, dc-ac inversion and utility backup. The reference home is compared to others in regions of different insolation. Major material requirements, scaled to quad levels of end-use energy include significant quantities of silicon, copper, lead, antimony, sulfuric acid and plastics. Operating residuals generated are negligible with the exception of those from the storage battery due to a short (10-year) lifetime. A brief general discussion of other environmental, health, and safety and resource availability impacts is presented. It is suggested that solar cell materials production and fabrication may have the major environmental impact when comparing all facets of photovoltaic system usage. Fabrication of the various types of solar cell systems involves the need, handling, and transportation of many toxic and hazardous chemicals with attendant health and safety impacts. Increases in production of such materials as lead, antimony, sulfuric acid, copper, plastics, cadmium and gallium will be required should large scale usage of photovoltaic systems be implemented.

  12. Potential high efficiency solar cells: Applications from space photovoltaic research

    NASA Technical Reports Server (NTRS)

    Flood, D. J.

    1986-01-01

    NASA involvement in photovoltaic energy conversion research development and applications spans over two decades of continuous progress. Solar cell research and development programs conducted by the Lewis Research Center's Photovoltaic Branch have produced a sound technology base not only for the space program, but for terrestrial applications as well. The fundamental goals which have guided the NASA photovoltaic program are to improve the efficiency and lifetime, and to reduce the mass and cost of photovoltaic energy conversion devices and arrays for use in space. The major efforts in the current Lewis program are on high efficiency, single crystal GaAs planar and concentrator cells, radiation hard InP cells, and superlattice solar cells. A brief historical perspective of accomplishments in high efficiency space solar cells will be given, and current work in all of the above categories will be described. The applicability of space cell research and technology to terrestrial photovoltaics will be discussed.

  13. Photovoltaic Materials

    SciTech Connect

    Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A.

    2012-10-15

    The goal of the current project was to help make the US solar industry a world leader in the manufacture of thin film photovoltaics. The overall approach was to leverage ORNL’s unique characterization and processing technologies to gain a better understanding of the fundamental challenges for solar cell processing and apply that knowledge to targeted projects with industry members. ORNL has the capabilities in place and the expertise required to understand how basic material properties including defects, impurities, and grain boundaries affect the solar cell performance. ORNL also has unique processing capabilities to optimize the manufacturing process for fabrication of high efficiency and low cost solar cells. ORNL recently established the Center for Advanced Thin-film Systems (CATS), which contains a suite of optical and electrical characterization equipment specifically focused on solar cell research. Under this project, ORNL made these facilities available to industrial partners who were interested in pursuing collaborative research toward the improvement of their product or manufacturing process. Four specific projects were pursued with industrial partners: Global Solar Energy is a solar industry leader in full scale production manufacturing highly-efficient Copper Indium Gallium diSelenide (CIGS) thin film solar material, cells and products. ORNL worked with GSE to develop a scalable, non-vacuum, solution technique to deposit amorphous or nanocrystalline conducting barrier layers on untextured stainless steel substrates for fabricating high efficiency flexible CIGS PV. Ferro Corporation’s Electronic, Color and Glass Materials (“ECGM”) business unit is currently the world’s largest supplier of metallic contact materials in the crystalline solar cell marketplace. Ferro’s ECGM business unit has been the world's leading supplier of thick film metal pastes to the crystalline silicon PV industry for more than 30 years, and has had operational cells and

  14. Life Cycle Greenhouse Gas Emissions from Solar Photovoltaics (Fact Sheet)

    SciTech Connect

    Not Available

    2012-11-01

    The National Renewable Energy Laboratory (NREL) recently led the Life Cycle Assessment (LCA) Harmonization Project, a study that helps to clarify inconsistent and conflicting life cycle GHG emission estimates in the published literature and provide more precise estimates of life cycle GHG emissions from PV systems.

  15. Method of manufacturing a large-area segmented photovoltaic module

    DOEpatents

    Lenox, Carl

    2013-11-05

    One embodiment of the invention relates to a segmented photovoltaic (PV) module which is manufactured from laminate segments. The segmented PV module includes rectangular-shaped laminate segments formed from rectangular-shaped PV laminates and further includes non-rectangular-shaped laminate segments formed from rectangular-shaped and approximately-triangular-shaped PV laminates. The laminate segments are mechanically joined and electrically interconnected to form the segmented module. Another embodiment relates to a method of manufacturing a large-area segmented photovoltaic module from laminate segments of various shapes. Other embodiments relate to processes for providing a photovoltaic array for installation at a site. Other embodiments and features are also disclosed.

  16. Superfund fact sheet: Benzene. Fact sheet

    SciTech Connect

    Not Available

    1992-09-01

    The fact sheet describes benzene, a chemical that can be found in a variety of products, including petroleum products (e.g. gasoline), some household cleaners, and some glues and adhesives. Explanations of how people are exposed to benzene and how benzene can enter the body and may affect human health are given. The fact sheet is one in a series providing reference information about Superfund issues and is intended for readers with no formal scientific training.

  17. Parametric analysis of stand-alone residential photovoltaic systems and the SOLSTOR simulation model

    NASA Astrophysics Data System (ADS)

    Caskey, D. L.; Aronson, E. A.; Murphy, K. D.

    Grid-connected residential photovoltaic (PV) systems have been studied in great detail during the past few years. However, stand-alone systems have received considerably less attention. This paper describes the results of an evaluation of the economic feasibility of stand-alone systems. The SOLSTOR simulation program, developed by Sandia, was the primary analysis tool. The results indicate that stand-alone PV systems offer considerable economic advantage over the fossil-fueled generator systems. This is true even with no escalation of fuel prices, with PV array costs of twice the 1986 DOE goal, with present day battery costs, and in the Northeast as well as in the Southwest part of the United States. The on-site generator was generally used less than 1400 hours per year, and in fact can be eliminated in many cases in the Southwest.

  18. A simplified solar cell array modelling program

    NASA Technical Reports Server (NTRS)

    Hughes, R. D.

    1982-01-01

    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.

  19. The ERDA/LeRC Photovoltaic Systems Test Facility

    NASA Technical Reports Server (NTRS)

    Forestieri, A. F.

    1978-01-01

    The ERDA/LeRC Photovoltaic Systems Test Facility (STF) provides a vital support function to the overall ERDA National Solar Photovoltaic Program. It allows preliminary investigation and checkout of components, subsystems, and complete photovoltaic systems before installation in actual service. The STF can also be used to determine optimum system configurations and operating modes. A facility description is presented, taking into account the solar cell array, the energy storage equipment, the power conditioning equipment, electric utility distribution network and loads, and instrumentation and data acquisition systems. Safety procedures which have been set up for maintenance and inspection of the solar array are discussed. Attention is also given to a number of investigations regarding the effect of environmental factors on solar cell array operation.

  20. Photovoltaic module electrical termination design requirement study. Final report

    SciTech Connect

    Mosna, F.J. Jr.; Donlinger, J.

    1980-07-01

    Motorola Inc., in conjunction with ITT Cannon, has conducted a study to develop information to facilitate the selection of existing, commercial, electrical termination hardware for photovoltaic modules and arrays. Details of the study are presented in this volume. Module and array design parameters were investigated and recommendations were developed for use in surveying, evaluating, and comparing electrical termination hardware. Electrical termination selection criteria factors were developed and applied to nine generic termination types in each of the four application sectors. Remote, residential, intermediate and industrial. Existing terminations best suited for photovoltaic modules and arrays were identified. Cost information was developed to identify cost drivers and/or requirements which might lead to cost reductions. The general conclusion is that there is no single generic termination that is best suited for photovoltaic application, but that the appropriate termination is strongly dependent upon the module construction and its support structure as well as the specific application sector.

  1. Structural Biology Fact Sheet

    MedlinePlus

    ... Home > Science Education > Structural Biology Fact Sheet Structural Biology Fact Sheet Tagline (Optional) Middle/Main Content Area What is structural biology? Structural biology is a field of science focused ...

  2. Cocaine (Coke, Crack) Facts

    MedlinePlus

    ... That People Abuse » Cocaine (Coke, Crack) Facts Cocaine (Coke, Crack) Facts Listen Cocaine is a white ... Version Download "My life was built around getting cocaine and getting high." Stacey is recovering from her ...

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    ... That People Abuse » Heroin (Smack, Junk) Facts Heroin (Smack, Junk) Facts Listen Heroin is a white ... Español English Español PDF Version Download "I needed heroin just to get by." Deon was addicted to ...

  4. Organ Facts: Pancreas

    MedlinePlus

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  5. Status of the ERDA/NASA photovoltaic tests and applications project

    NASA Technical Reports Server (NTRS)

    Deyo, J. N.; Brandhorst, H. W., Jr.; Forestieri, A. F.

    1976-01-01

    The Tests and Applications Project of the ERDA Photovoltaic Program is concerned with the testing of photovoltaic systems and the growth of their use in real terrestrial applications. This activity is an important complement to the development of low cost solar arrays by providing requirements based on application needs and stimulating markets to create demand to absorb increasing production capacity. A photovoltaic system test facility is now operational, market stimulation has been initiated through applications, and standards for terrestrial cell measurements established.

  6. Aeolian removal of dust from photovoltaic surfaces on Mars

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Perez-Davis, Marla E.; Marabito, Mark

    1990-01-01

    It is well documented that Mars is totally engulfed in huge dust storms nearly each Martian year. Dust elevated in these global dust storms, or in any of the numerous local dust storms could settle on photovoltaic surfaces and seriously hamper photovoltaic power system performance. Using a recently developed technique to uniformly dust simulated photovoltaic surfaces, samples were subjected to Martian-like winds in an attempt to determine whether natural aeolian processes on Mars would sweep off the settled dust. The effects of wind velocity, angle of attack, height off the Martian surface, and surface coating material were investigated. Principles which can help to guide the design of photovoltaic arrays bound for the Martian surface were uncovered. Most importantly, arrays mounted with an angle of attack approaching 45 deg show the most efficient clearing. Although the angular dependence is not sharp, horizontally mounted arrays required significantly higher wind velocities to clear off the dust. From the perspective of dust-clearing it appears that the arrays may be erected quite near the ground, but previous studies have suggested that saltation effects can be expected to cause such arrays to be covered by sand if they are set up less than about a meter from the ground. Providing that the surface chemistry of Martian dusts is comparable to our test dust, the materials used for protective coating may be optimized for other considerations such as transparency, and chemical or abrasion resistance. The static threshold velocity is low enough that there are regions on Mars which experience winds strong enough to clear off a photovoltaic array if it is properly oriented. Turbulence fences proved to be an ineffective strategy to keep dust cleared from the photovoltaic surfaces.

  7. Design of a photovoltaic central power station

    SciTech Connect

    Not Available

    1984-02-01

    Photovoltaic central power station designs have been developed for both high-efficiency flat-panel arrays and two-axis tracking concentrator arrays. Both designs are based on a site adjacent to the Saguaro Power Station of Arizona Public Service. The plants are 100 MW each, made of 5 MW subfields. The site specific designs allow detailed cost estimate for site preparation, installation, and engineering. These designs are summarized and cost estimates analyzed. Provided also are recommendations for future work to reduce system cost for each plant design.

  8. Photovoltaic applications of Compound Parabolic Concentrator (CPC)

    NASA Technical Reports Server (NTRS)

    Winston, R.

    1975-01-01

    The use of a compound parabolic concentrator as field collector, in conjunction with a primary focusing concentrator for photovoltaic applications is studied. The primary focusing concentrator can be a parabolic reflector, an array of Fresnel mirrors, a Fresnel lens or some other lens. Silicon solar cell grid structures are proposed that increase efficiency with concentration up to 10 suns. A ray tracing program has been developed to determine energy distribution at the exit of a compound parabolic concentrator. Projected total cost of a CPC/solar cell system will be between 4 and 5 times lower than for flat plate silicon cell arrays.

  9. Photovoltaic technology assessment

    SciTech Connect

    Backus, C.E.

    1981-01-01

    After a brief review of the history of photovoltaic devices and a discussion of the cost goals set for photovoltaic modules, the status of photovoltaic technology is assessed. Included are discussions of: current applications, present industrial production, low-cost silicon production techniques, energy payback periods for solar cells, advanced materials research and development, concentrator systems, balance-of-system components. Also discussed are some nontechnical aspects, including foreign markets, US government program approach, and industry attitudes and approaches. (LEW)

  10. Photovoltaics - The endless spring

    NASA Technical Reports Server (NTRS)

    Brandhorst, H. W., Jr.

    1984-01-01

    An overview of the developments in the photovoltaic field over the past decade or two is presened. Accomplishments in the terrestrial field are reviewed along with projections and challenges toward meeting cost goals. The contrasts and commonality of space and terrestrial photovoltaics are presented. Finally, a strategic philosophy of photovoltaics research highlighting critical factors, appropriate directions, emerging opportunities, and challenges of the future is given.

  11. Photovoltaics: The endless spring

    NASA Technical Reports Server (NTRS)

    Brandhorst, H. W., Jr.

    1984-01-01

    An overview of the developments in the photovoltaic field over the past decade or two is presented. Accomplishments in the terrestrial field are reviewed along with projections and challenges toward meeting cost goals. The contrasts and commonality of space and terrestrial photovoltaics are presented. Finally, a strategic philosophy of photovoltaics research highlighting critical factors, appropriate directions, emerging opportunities, and challenges of the future is given.

  12. Photovoltaic development in Argentina

    SciTech Connect

    Godfrin, E.M.; Duran, J.C.; Frigerio, A.; Moragues, J.A.

    1994-12-31

    A critical assessment of the photovoltaic program in Argentina is presented. Research and development activities on photovoltaic cells as well as industrial and technological development are still in the initial stages. Activities accomplished by the Atomic Energy Commission (CNEA) and the Institute of Technology Development for the Chemical industry (INTEC) are briefly described. The evolution of photovoltaic installations in Argentina is analyzed and accumulative data up to 1993 are given. A summary of the potential market for photovoltaic systems in the short and medium term is presented.

  13. Photovoltaic Test and Demonstration Project. [for solar cell power systems

    NASA Technical Reports Server (NTRS)

    Forestieri, A. F.; Brandhorst, H. W., Jr.; Deyo, J. N.

    1976-01-01

    The Photovoltaic Test and Demonstration Project was initiated by NASA in June, 1975, to develop economically feasible photovoltaic power systems suitable for a variety of terrestrial applications. Objectives include the determination of operating characteristic and lifetimes of a variety of solar cell systems and components and development of methodology and techniques for accurate measurements of solar cell and array performance and diagnostic measurements for solar power systems. Initial work will be concerned with residential applications, with testing of the first prototype system scheduled for June, 1976. An outdoor 10 kW array for testing solar power systems is under construction.

  14. Manufacturing injection-moleded Fresnel lens parquets for point-focus concentrating photovoltaic systems

    SciTech Connect

    Peters, E.M.; Masso, J.D.

    1995-10-01

    This project involved the manufacturing of curved-faceted, injection-molded, four-element Fresnel lens parquets for concentrating photovoltaic arrays. Previous efforts showed that high-efficiency (greater than 82%) Fresnel concentrators could be injection molded. This report encompasses the mold design, molding, and physical testing of a four-lens parquet for a solar photovoltaic concentrator system.

  15. Design of a photovoltaic system for a southwest all-electric residence

    NASA Astrophysics Data System (ADS)

    Mehalick, E. M.; Obrien, G.; Tully, G. F.; Johnson, J.; Parker, J.

    1980-04-01

    The grid connected residential photovoltaic system for the Southwest is designed to meet both space conditioning requirements and all conventional electrical load requirements for an all-electric residence. The system is comprised of two major subsystems, the solar array and the power conditioning subsystem (PCS). An 8 kW peak photovoltaic array been designed for the house. The 93 square meters solar array uses a shingle solar cell module in a highly redundant series/parallel matrix. The photovoltaic generated power is supplied to a 10kVA power conversion subsystem which is controlled to track the solar array maximum power operating point and feed the 240 Vac output power directly to the house loads or back to the utility when excess power is generated. The photovoltaic power is isolated from the utility by a 15 kVA transformer. The house design and subsystem specifications are given in detail.

  16. Proceedings of the First ERDA Semiannual Solar Photovoltaic Conversion Program Conference

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Organization, basic research and applied technology for the Solar Photovoltaic Conversion Program are outlined. The program aims to provide a technology base for low cost thin film solar cells and solar arrays.

  17. Facts about Hib Disease. ARC Facts.

    ERIC Educational Resources Information Center

    Association for Retarded Citizens, Arlington, TX.

    The fact sheet provides basic information about Hib Disease in young children, which may involve a bacterial meningitis causing mental retardation, hearing loss, partial blindness, speech disorders, partial paralysis, behavioral problems, or seizures. Stressed is prevention of Hib Disease through immunization. The question and answer format…

  18. Operation and maintenance cost data for residential photovoltaic modules/panels

    NASA Astrophysics Data System (ADS)

    Oster, J. R., Jr.; Zaremski, D. R., Jr.; Albert, E. M.; Hawkins, S. L.

    1980-07-01

    Costs associated with the operation and maintenance of residential photovoltaic modules and arrays are studied. Six basic topics related to operation and maintenance to photovoltaic arrays are investigated: maintenance; cleaning; panel replacement; gasket repair/replacement; wiring repair/replacement; and termination repair/replacement. The effects of the mounting types (rack mount, stand off mount, direct mount and integral mount) and the installation/replacement type (sequential, partial interruption and independent) are identified and described. Methods of reducing maintenance costs are suggested.

  19. Operation and maintenance cost data for residential photovoltaic modules/panels

    NASA Technical Reports Server (NTRS)

    Oster, J. R., Jr.; Zaremski, D. R., Jr.; Albert, E. M.; Hawkins, S. L.

    1980-01-01

    Costs associated with the operation and maintenance of residential photovoltaic modules and arrays are studied. Six basic topics related to operation and maintenance to photovoltaic arrays are investigated: maintenance; cleaning; panel replacement; gasket repair/replacement; wiring repair/replacement; and termination repair/replacement. The effects of the mounting types (rack mount, stand off mount, direct mount and integral mount) and the installation/replacement type (sequential, partial interruption and independent) are identified and described. Methods of reducing maintenance costs are suggested.

  20. Microsystems Enabled Photovoltaics

    SciTech Connect

    Gupta, Vipin; Nielson, Greg; Okandan, Murat, Granata, Jennifer; Nelson, Jeff; Haney, Mike; Cruz-Campa, Jose Luiz

    2012-07-02

    Sandia's microsystems enabled photovoltaic advances combine mature technology and tools currently used in microsystem production with groundbreaking advances in photovoltaics cell design, decreasing production and system costs while improving energy conversion efficiency. The technology has potential applications in buildings, houses, clothing, portable electronics, vehicles, and other contoured structures.

  1. Microsystems Enabled Photovoltaics

    ScienceCinema

    Gupta, Vipin; Nielson, Greg; Okandan, Murat, Granata, Jennifer; Nelson, Jeff; Haney, Mike; Cruz-Campa, Jose Luiz

    2016-07-12

    Sandia's microsystems enabled photovoltaic advances combine mature technology and tools currently used in microsystem production with groundbreaking advances in photovoltaics cell design, decreasing production and system costs while improving energy conversion efficiency. The technology has potential applications in buildings, houses, clothing, portable electronics, vehicles, and other contoured structures.

  2. Solar Photovoltaic Cells.

    ERIC Educational Resources Information Center

    Mickey, Charles D.

    1981-01-01

    Reviews information on solar radiation as an energy source. Discusses these topics: the key photovoltaic material; the bank theory of solids; conductors, semiconductors, and insulators; impurity semiconductors; solid-state photovoltaic cell operation; limitations on solar cell efficiency; silicon solar cells; cadmium sulfide/copper (I) sulfide…

  3. Photovoltaics industry profile

    NASA Astrophysics Data System (ADS)

    1980-10-01

    A description of the status of the U.S. photovoltaics industry is given. Principal end user industries are identified, domestic and foreign market trends are discussed, and industry organized and U.S. government organized trade promotion events are listed. Trade associations and trade journals are listed, and a photovoltaic product manufacturers list is included.

  4. Solar Photovoltaic Energy.

    ERIC Educational Resources Information Center

    Ehrenreich, Henry; Martin, John H.

    1979-01-01

    The goals of solar photovoltaic technology in contributing to America's future energy needs are presented in this study conducted by the American Physical Society. Although the time needed for photovoltaics to become popular is several decades away, according to the author, short-range applications are given. (Author/SA)

  5. Characterization of Photovoltaic Generators

    ERIC Educational Resources Information Center

    Boitier, V.; Cressault, Y.

    2011-01-01

    This paper discusses photovoltaic panel systems and reviews their electrical properties and use in several industrial fields. We explain how different photovoltaic panels may be characterized by undergraduate students at university using simple methods to retrieve their electrical properties (power, current and voltage) and compare these values…

  6. Making America's Buildings Better (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    This fact sheet is an overview of the U.S. Department of Energy's Building Technologies program. Buildings use more energy than any other sector of the U.S. economy? In fact, buildings consume more than 70% of the electricity and more than 50% of the natural gas Americans use. That's why the U.S. Department of Energy's (DOE's) Building Technologies Program (BTP) is working to improve building energy performance through high-impact research, out-reach, and regulatory efforts. These efforts will result in affordable, high-performance homes and commercial buildings. These grid-connected buildings will be more energy efficient than today's typical buildings, with renewable energy providing a portion of the power needs. They will combine energy-smart 'whole building' design and construction, appliances and equipment that minimize plug loads, and cost-effective photovoltaics or other on-site energy systems.

  7. Carbon Nanotubes for Polymer Photovoltaics

    NASA Astrophysics Data System (ADS)

    Anctil, Annick; Dileo, Roberta; Schauerman, Chris; Landi, Brian; Raffaelle, Ryne

    2007-03-01

    Carbon nanotubes are being investigated for optical absorption, exciton dissociation, and carrier transport in polymer photovoltaic devices. In the present work, single wall carbon nanotubes (SWNTs) were synthesized by an Alexandrite pulsed laser vaporization reactor at standard conditions and purified based upon our previously reported TOP procedure. The SWNTs were dispersed in polymer composites for pure MEH-PPV, pure P3HT, and [C60]-PCBM-P3HT (1:1 by weight) as a function of nanotube weight loading (0.1 -- 5% w/w). The AM0 current-voltage measurements for structures sandwiched between PEDOT/PSS coated ITO substrates and an evaporated aluminum contact demonstrate the dramatic effect of SWNT content on the short circuit current density, with conversions efficiencies consistently greater than 1%. The temperature coefficient for nanotube-containing polymer photovoltaics has been compared to conventional PCBM-P3HT devices, and the general relationship of increasing efficiency with increasing temperature is observed. However, the necessity to control nanotube percolation to prevent device shunting has led to recent developments which focus on controlling nanotube length through oxidative cutting, the deposition of intrinsic polymer layers, and the use of aligned carbon nanotube arrays for preferential charge transport.

  8. Firefighter safety and photovoltaic installations research project

    NASA Astrophysics Data System (ADS)

    Backstrom, Robert; Dini, Dave

    2012-10-01

    Under the United States Department of Homeland Security (DHS) Assistance to Fire Fighters grant, UL LLC examined fire service concerns of photovoltaic (PV) systems. These concerns included firefighter vulnerability to electrical and casualty hazards when mitigating a fire involving photovoltaic (PV) modules systems. Findings include: 1. The electric shock hazard due to application of water is dependent on voltage, water conductivity, distance and spray pattern of the suppression stream. 2. Outdoor weather exposure rated electrical enclosures are not resistant to water penetration by fire hose streams. 3. Firefighter's gloves and boots afford limited protection against electrical shock provided the insulating surface is intact and dry. 4. "Turning off" an array is not a simple matter of opening a disconnect switch. 5. Tarps offer varying degrees of effectiveness. 6. Fire equipment scene lighting and exposure fires may illuminate PV systems sufficiently to cause a lock-on hazard. 7. Severely damaged PV arrays are capable of producing hazardous conditions. 8. Damage to modules from tools may result in both electrical and fire hazards. 9. Severing of conductors in both metal and plastic conduit results in electrical and fire hazards. 10. Responding personnel must stay away from the roofline in the event of modules or sections of an array sliding off the roof. 11. Fires under an array but above the roof may breach roofing materials and decking allowing fire to propagate into the attic space. Several tactical considerations were developed utilizing the data from the experiments.

  9. Developing Fact Sheets.

    ERIC Educational Resources Information Center

    Weiler, Robert M.

    1998-01-01

    Presents an assignment that allows preservice health educators to learn how to develop fact sheets for communicating health information. The process of developing fact sheets involves selecting a topic, selecting a target audience, researching the topic, writing the message, constructing the draft, and pretesting the product. Strategies for…

  10. Facts for Feeding Series.

    ERIC Educational Resources Information Center

    Academy for Educational Development, Washington, DC.

    This document compiles several fact sheets, in multiple languages, for mothers and parent educators providing information and answering questions concerning breastfeeding infants. The fact sheets are published in English, French, and Spanish, and cover the following topics: (1) "Recommended Practices To Improve Infant Nutrition during the First…

  11. Reading Recovery. [Fact Sheets].

    ERIC Educational Resources Information Center

    Reading Recovery Council of North America, Columbus, OH.

    This set of 10 fact sheets (each 2 to 4 pages long) addresses aspects of Reading Recovery, a program that helps children to be proficient readers and writers by the end of the first grade. It discusses the basic facts of Reading Recovery; Reading Recovery for Spanish literacy; Reading Recovery lessons; Reading Recovery professional development;…

  12. Assessing Basic Fact Fluency

    ERIC Educational Resources Information Center

    Kling, Gina; Bay-Williams, Jennifer M.

    2014-01-01

    In this article, the authors share a variety of ways to formatively assess basic fact fluency. The define fluency, raise some issues related to timed testing, and then share a collection of classroom-tested ideas for authentic fact fluency assessment. This article encourages teachers to try a variety of alternative assessments from this sampling,…

  13. AIDS Fact Pack.

    ERIC Educational Resources Information Center

    Center for Population Options, Washington, DC.

    The three fact sheets presented in this document address issues surrounding adolescent sexuality and sexually transmitted diseases (STDs), especially the Acquired Immune Deficiency Syndrome (AIDS). The first fact sheet, "Young Women and AIDS: A Worldwide Perspective," suggests that since open discussions of adolescent sexuality have long been…

  14. Limits on cloud-induced fluctuation in photovoltaic generation

    SciTech Connect

    Jewell, W.T. ); Unruh, T.D. )

    1990-03-01

    When cloud shadows move across a photovoltaic (PV) array, the array's power output is reduced. It resumes full production when the shadow moves away. The utility must follow these changes with other types of generations. Under certain cloud conditions, the changes can be large and fast. A methodology is presented to assess the cost of such fluctuations and their effect on a utility's ability to serve its load. A case study is also presented.

  15. NREL Develops Technique to Measure Membrane Thickness and Defects in Polymer Electrode Membrane Fuel Cells (Fact Sheet)

    SciTech Connect

    Not Available

    2010-11-01

    This fact sheet describes NREL's accomplishments in fuel cell membrane electrode assembly research and development. Work was performed by the Hydrogen Technologies and Systems Center and the National Center for Photovoltaics.

  16. Issues and opportunities in space photovoltaics

    NASA Technical Reports Server (NTRS)

    Francis, Robert W.; Somerville, W. A.; Flood, Dennis J.

    1988-01-01

    Space power sources are becoming a central focus for determining man's potential and schedule for exploring and utilizing the benefits of space. The ability to search, probe, survey, and communicate throughout the universe will depend on providing adequate power to the instruments to do these jobs. Power requirements for space platforms are increasing and will continue to increase into the 21st century. Photovoltaics have been a dependable power source for space for the last 30 years and have served as the primary source of power on virtually all DOD and NASA satellites. The performance of silicon (Si) solar cells has increased from 10 percent air mass zero (AM0) solar energy conversion efficiency in the early 60's to almost 15 percent on today's spacecraft. Some technologists even think that the potential for solar photovoltaics has reached a plateau. However, present and near-future Air Force and NASA requirements show needs that, if the problems are looked upon as opportunities, can elevate the photovoltaic power source scientist and array structure engineer into the next technological photovoltaic growth curve.

  17. 17th Space Photovoltaic Research and Technology Conference

    NASA Technical Reports Server (NTRS)

    Jenkins, Phillip (Compiler)

    2002-01-01

    The 17th Space Photovoltaic Research and Technology (SPRAT XVII) Conference was held September 11-13, 2001, at the Ohio Aerospace Institute (OAI) in Cleveland, Ohio. The SPRAT conference, hosted by the Photovoltaic and Space Environments Branch of the NASA Glenn Research Center, brought together representatives of the space photovoltaic community from around the world to share the latest advances in space solar technology. This year's conference continued to build on many of the trends shown in SPRAT XVI; the use of new high-efficiency cells for commercial use and the development of novel array concepts such as Boeing's Solar Tile concept. In addition, new information was presented on space environmental interactions with solar arrays.

  18. 17th Space Photovoltaic Research and Technology Conference

    NASA Astrophysics Data System (ADS)

    Jenkins, Phillip

    2002-10-01

    The 17th Space Photovoltaic Research and Technology (SPRAT XVII) Conference was held September 11-13, 2001, at the Ohio Aerospace Institute (OAI) in Cleveland, Ohio. The SPRAT conference, hosted by the Photovoltaic and Space Environments Branch of the NASA Glenn Research Center, brought together representatives of the space photovoltaic community from around the world to share the latest advances in space solar technology. This year's conference continued to build on many of the trends shown in SPRAT XVI; the use of new high-efficiency cells for commercial use and the development of novel array concepts such as Boeing's Solar Tile concept. In addition, new information was presented on space environmental interactions with solar arrays.

  19. Photovoltaic Power Plants

    NASA Astrophysics Data System (ADS)

    Berman, Elliot

    1986-11-01

    To demonstrate technical viability of photovoltaic modules in central, grid connected energy systems, ARCO Solar, Inc. has designed, installed and is operating two photovoltaic power plants on the megawatt scale. These systems use two-axis tracking. The first generation plant in Lugo (Hesperia), California, with a nominal rating of one MWpk (DC)" was installed in 1982 in the Southern California Edison Company grid. The second system, rated at 6.4 MWDk (DC), is located in the Carrisa Plain in California and connected to the Pacific Gas and Electric Company grid. Based on the cost and performance data from these installations, an assessment of the current status and future needs of large scale photovoltaic energy systems is made. With each new system, improved techniques of design, installation and system integration have been developed. Expectations have been confirmed as to the performance and adaptability of solar cells, especially the ease of incremental increases in capacity when needed. Modular photovoltaic systems have been found to be easy to build and operate, and to be highly reliable. Prologue: Technological advancement usually requires good science and logical engineering. In the main, faith, persistence and feel are also required. Rule: The balance-of-system costs for photovoltaic energy systems equal photovoltaic module costs. Photovoltaic systems have progressed to their current stage of high promise because of faith, persistence, feel and belief in this rule.

  20. Photovoltaics for high capacity space power systems

    NASA Technical Reports Server (NTRS)

    Flood, Dennis J.

    1988-01-01

    The anticipated energy requirements of future space missions will grow by factors approaching 100 or more, particularly as a permanent manned presence is established in space. The advances that can be expected in solar array performance and lifetime, when coupled with advanced, high energy density storage batteries and/or fuel cells, will continue to make photovoltaic energy conversion a viable power generating option for the large systems of the future. The specific technologies required to satisfy any particular set of power requirements will vary from mission to mission. Nonetheless, in almost all cases the technology push will be toward lighter weight and higher efficiency, whether of solar arrays of storage devices. This paper will describe the content and direction of the current NASA program in space photovoltaic technology. The paper will also discuss projected system level capabilities of photovoltaic power systems in the context of some of the new mission opportunities under study by NASA, such as a manned lunar base, and a manned visit to Mars.

  1. Photovoltaics for high capacity space power systems

    NASA Technical Reports Server (NTRS)

    Flood, Dennis J.

    1988-01-01

    The anticipated energy requirements of future space missions will grow by factors approaching 100 or more, particularly as a permanent manned presence is established in space. The advances that can be expected in solar array performance and lifetime, when coupled with advanced, high energy density storage batteries and/or fuel cells, will continue to make photovoltaic energy conversion a viable power generating option for the large systems of the future. The specific technologies required to satisfy any particular set of power requirements will vary from mission to mission. Nonetheless, in almost all cases the technology push will be toward lighter weight and higher efficiency, whether of solar arrays or storage devices. This paper will describe the content and direction of the current NASA program in space photovoltaic technology. The paper will also discuss projected system level capabilities of photovoltaic power systems in the context of some of the new mission opportunities under study by NASA, such as a manned lunar base, and a manned visit to Mars.

  2. ERDA/Lewis research center photovoltaic systems test facility

    NASA Technical Reports Server (NTRS)

    Forestieri, A. F.; Johnson, J. A.; Knapp, W. D.; Rigo, H.; Stover, J.; Suhay, R.

    1977-01-01

    A national photovoltaic power systems test facility (of initial 10-kW peak power rating) is described. It consists of a solar array to generate electrical power, test-hardware for several alternate methods of power conversion, electrical energy storage systems, and an instrumentation and data acquisition system.

  3. Performance of a photovoltaically powered air-conditioning system

    SciTech Connect

    Kern, Jr, E. C.; Millner, A. R.

    1980-01-01

    A vapor-compression air conditioner coupled directly to a photovoltaic array is discussed. Previous analyses of such a system are reviewed, and a development system designed to test the concept is described. Preliminary experiments indicate that the performance of this initial system falls considerably short of analytic expectations.

  4. Data acquisition at a residential photovoltaic system

    NASA Astrophysics Data System (ADS)

    McIntyre, J. M.; Miller, G. N.

    A description is presented of the techniques employed for data collection and analysis in the study of a small residential photovoltaic (PV) system. A model home of approximately 139 sq m incorporated a PV array on the south-facing roof. The PV system was designed to interface directly to the local utility system through an inverter which converted the direct current output of the array to 60 Hz alternating current. Electric power could flow either from the utility lines into the house or vice versa. The solar panel consisted of 120 modules installed in a 5 x 24 array. Attention is given to initial problems, the conduction of a systems analysis, the data collection method, the equipment used in the data acquisition system, aspects of data collection, the encountered problems, and the results of the data acquisition project. It was found that the data acquisition system employed was effective for computer-compatible data collection.

  5. Magnetic arrays

    DOEpatents

    Trumper, David L.; Kim, Won-jong; Williams, Mark E.

    1997-05-20

    Electromagnet arrays which can provide selected field patterns in either two or three dimensions, and in particular, which can provide single-sided field patterns in two or three dimensions. These features are achieved by providing arrays which have current densities that vary in the windings both parallel to the array and in the direction of array thickness.

  6. Magnetic arrays

    DOEpatents

    Trumper, D.L.; Kim, W.; Williams, M.E.

    1997-05-20

    Electromagnet arrays are disclosed which can provide selected field patterns in either two or three dimensions, and in particular, which can provide single-sided field patterns in two or three dimensions. These features are achieved by providing arrays which have current densities that vary in the windings both parallel to the array and in the direction of array thickness. 12 figs.

  7. Design of a side-by-side photovoltaic thermal system for a Northeast all-electric residence

    NASA Astrophysics Data System (ADS)

    Mehalick, E. M.; Obrien, G.; Tully, G. F.; Johnson, J.; Parker, J.; Truncellito, N.; Felice, R.

    1980-11-01

    There are three major system elements: the photovoltaic array, the electric power conversion subsystem, and the thermal subsystem. A key to the sizing of the PV and thermal array is the relative cost of each system. Therefore, the ratio of the costs associated with each system was varied parametrically to define ultimate sizing of the PV and thermal array. In general, the results indicate larger PV array area and minimal thermal array area for the set of cost assumptions described.

  8. CPR Facts and Stats

    MedlinePlus

    ... CPR About CPR & First Aid CPR Facts & Stats History of CPR Cardiac Arrest vs. Heart Attack International ... Training Kits RQI AHA Instructors ECC Educational Conferences Programs CPR In Schools Hands-Only CPR ...

  9. Cerebral Aneurysms Fact Sheet

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS Cerebral Aneurysms Fact Sheet See a list of all NINDS ... I get more information? What is a cerebral aneurysm? A cerebral aneurysm (also known as an intracranial ...

  10. Facts about Physical Activity

    MedlinePlus

    ... Physical Activity Overweight & Obesity Healthy Weight Breastfeeding Micronutrient Malnutrition State and Local Programs Facts about Physical Activity ... Physical Activity Overweight & Obesity Healthy Weight Breastfeeding Micronutrient Malnutrition State and Local Programs File Formats Help: How ...

  11. Facts about Botulism

    MedlinePlus

    ... Training Materials Q fever Info & Guidance for Clinicians Salmonella Shigella Smallpox Smallpox Basics Vaccine Basics Clinicians Vaccination ... Metals Nerve Agents Pulmonary Agents Riot Control Agents Toxic Alcohols Vesicants Chemical-Specific Fact Sheets Toxicology FAQs ...

  12. Facts about Folic Acid

    MedlinePlus

    ... Information For... Media Policy Makers Facts About Folic Acid Language: English Español (Spanish) Recommend on Facebook Tweet ... of the baby's brain and spine. About folic acid Folic acid is a B vitamin. Our bodies ...

  13. Avian Fact Sheet

    SciTech Connect

    NWCC Wildlife Work Group

    2004-12-01

    OAK-B135 After conducting four national research meetings, producing a document guiding research: Metrics and Methods for Determining or Monitoring Potential Impacts on Birds at Existing and Proposed Wind Energy Sites, 1999, and another paper, Avian Collisions with Wind Turbines: A Summary of Existing Studies and Comparisons to Other Sources of Avian Collision Mortality in the United States, 2001, the subcommittee recognized a need to summarize in a short fact sheet what is known about avian-wind interaction and what questions remain. This fact sheet attempts to summarize in lay terms the result of extensive discussion about avian-wind interaction on land. This fact sheet does not address research conducted on offshore development. This fact sheet is not intended as a conclusion on the subject; rather, it is a summary as of Fall/Winter 2002.

  14. Pulsed laser illumination of photovoltaic cells

    NASA Technical Reports Server (NTRS)

    Yater, Jane A.; Lowe, Roland A.; Jenkins, Phillip P.; Landis, Geoffrey A.

    1994-01-01

    In future space missions, free electron lasers (FEL) may be used to illuminate photovoltaic array receivers to provide remote power. Both the radio-frequency (RF) and induction FEL provide FEL produce pulsed rather than continuous output. In this work we investigate cell response to pulsed laser light which simulates the RF FEL format. The results indicate that if the pulse repetition is high, cell efficiencies are only slightly reduced compared to constant illumination at the same wavelength. The frequency response of the cells is weak, with both voltage and current outputs essentially dc in nature. Comparison with previous experiments indicates that the RF FEL pulse format yields more efficient photovoltaic conversion than does an induction FEL pulse format.

  15. Photovoltaic solar cell

    DOEpatents

    Nielson, Gregory N; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J

    2014-05-20

    A photovoltaic solar cell for generating electricity from sunlight is disclosed. The photovoltaic solar cell comprises a plurality of spaced-apart point contact junctions formed in a semiconductor body to receive the sunlight and generate the electricity therefrom, the plurality of spaced-apart point contact junctions having a first plurality of regions having a first doping type and a second plurality of regions having a second doping type. In addition, the photovoltaic solar cell comprises a first electrical contact electrically connected to each of the first plurality of regions and a second electrical contact electrically connected to each of the second plurality of regions, as well as a passivation layer covering major surfaces and sidewalls of the photovoltaic solar cell.

  16. Photovoltaic solar cell

    DOEpatents

    Nielson, Gregory N; Okandan, Murat; Cruz-Campa, Jose Luis; Resnick, Paul J

    2013-11-26

    A photovoltaic solar cell for generating electricity from sunlight is disclosed. The photovoltaic solar cell comprises a plurality of spaced-apart point contact junctions formed in a semiconductor body to receive the sunlight and generate the electicity therefrom, the plurality of spaced-apart point contact junctions having a first plurality of regions having a first doping type and a second plurality of regions having a second doping type. In addition, the photovoltaic solar cell comprises a first electrical contact electrically connected to each of the first plurality of regions and a second electrical contact electrically connected to each of the second plurality of regions, as well as a passivation layer covering major surfaces and sidewalls of the photovoltaic solar cell.

  17. Biodiesel Basics (Fact Sheet)

    SciTech Connect

    Not Available

    2014-06-01

    This fact sheet provides a brief introduction to biodiesel, including a discussion of biodiesel blends, which blends are best for which vehicles, where to buy biodiesel, how biodiesel compares to diesel fuel in terms of performance, how biodiesel performs in cold weather, whether biodiesel use will plug vehicle filters, how long-term biodiesel use may affect engines, biodiesel fuel standards, and whether biodiesel burns cleaner than diesel fuel. The fact sheet also dismisses the use of vegetable oil as a motor fuel.

  18. Photovoltaic module and interlocked stack of photovoltaic modules

    DOEpatents

    Wares, Brian S.

    2014-09-02

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame. A plurality of individual male alignment features and a plurality of individual female alignment features are included on each frame. Adjacent photovoltaic modules are interlocked by multiple individual male alignment features on a first module of the adjacent photovoltaic modules fitting into and being surrounded by corresponding individual female alignment features on a second module of the adjacent photovoltaic modules. Other embodiments, features and aspects are also disclosed.

  19. Photovoltaic systems and applications

    SciTech Connect

    Not Available

    1982-01-01

    Abstracts are given of presentations given at a project review meeting held at Albuquerque, NM. The proceedings cover the past accomplishments and current activities of the Photovoltaic Systems Research, Balance-of-System Technology Development and System Application Experiments Projects at Sandia National Laboratories. The status of intermediate system application experiments and residential system analysis is emphasized. Some discussion of the future of the Photovoltaic Program in general, and the Sandia projects in particular is also presented.

  20. Photovoltaics on Landfills in Puerto Rico

    SciTech Connect

    Salasovich, J.; Mosey, G.

    2011-01-01

    The U.S. Environmental Protection Agency (EPA), in accordance with the RE-Powering America's Land initiative, selected the Commonwealth of Puerto Rico for a feasibility study of m0treAlables on several brownfield sites. The EPA defines a brownfield as 'a property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant.' All of the brownfields in this study are landfill sites. Citizens of Puerto Rico, city planners, and site managers are interested in redevelopment uses for landfills in Puerto Rico, which are particularly well suited for solar photovoltaic (PV) installation. The purpose of this report is to assess the landfills with the highest potential for possible solar PV installation and estimate cost, performance, and site impacts of three different PV options: crystalline silicon (fixed-tilt), crystalline silicon (single-axis tracking), and thin film (fixed-tilt). Each option represents a standalone system that can be sized to use an entire available site area. In addition, the report outlines financing options that could assist in the implementation of a system. The feasibility of PV systems installed on landfills is highly impacted by the available area for an array, solar resource, operating status, landfill cap status, distance to transmission lines, and distance to major roads. All of the landfills in Puerto Rico were screened according to these criteria in order to determine the sites with the greatest potential. Eight landfills were chosen for site visits based on the screening criteria and location. Because of time constraints and the fact that Puerto Rico is a relatively large island, the eight landfills for this visit were all located in the eastern half of the island. The findings from this report can be applied to landfills in the western half of the island. The economics of a potential PV system on landfills in Puerto Rico depend greatly on the

  1. Si Wire-Array Solar Cells

    NASA Astrophysics Data System (ADS)

    Boettcher, Shannon

    2010-03-01

    Micron-scale Si wire arrays are three-dimensional photovoltaic absorbers that enable orthogonalization of light absorption and carrier collection and hence allow for the utilization of relatively impure Si in efficient solar cell designs. The wire arrays are grown by a vapor-liquid-solid-catalyzed process on a crystalline (111) Si wafer lithographically patterned with an array of metal catalyst particles. Following growth, such arrays can be embedded in polymethyldisiloxane (PDMS) and then peeled from the template growth substrate. The result is an unusual photovoltaic material: a flexible, bendable, wafer-thickness crystalline Si absorber. In this paper I will describe: 1. the growth of high-quality Si wires with controllable doping and the evaluation of their photovoltaic energy-conversion performance using a test electrolyte that forms a rectifying conformal semiconductor-liquid contact 2. the observation of enhanced absorption in wire arrays exceeding the conventional light trapping limits for planar Si cells of equivalent material thickness and 3. single-wire and large-area solid-state Si wire-array solar cell results obtained to date with directions for future cell designs based on optical and device physics. In collaboration with Michael Kelzenberg, Morgan Putnam, Joshua Spurgeon, Daniel Turner-Evans, Emily Warren, Nathan Lewis, and Harry Atwater, California Institute of Technology.

  2. Elastomer Encapsulant for Solar-Cell Arrays

    NASA Technical Reports Server (NTRS)

    Baum, B.; Willis, P. B.

    1985-01-01

    Butyl acrylate syrups useful potting compounds for encapsulating photovoltaic cells in modular arrays. Material pourable liquid pumped into module, then cured to rubbery consistency. Cured material is thermoset elastomer highly transparent, low cost, flexible and with good low-temperature properties.

  3. LSSA (Low-cost Silicon Solar Array) project

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The Photovoltaic Conversion Program was established to find methods of economically generating enough electrical power to meet future requirements. Activities and progress in the following areas are discussed: silicon-refinement processes; silicon-sheet-growth techniques; encapsulants; manufacturing of off-the-shelf solar arrays; and procurement of semistandardized solar arrays.

  4. Photovoltaic restoration of sight with high visual acuity

    PubMed Central

    Lorach, Henri; Goetz, Georges; Smith, Richard; Lei, Xin; Mandel, Yossi; Kamins, Theodore; Mathieson, Keith; Huie, Philip; Harris, James; Sher, Alexander; Palanker, Daniel

    2015-01-01

    Patients with retinal degeneration lose sight due to gradual demise of photoreceptors. Electrical stimulation of the surviving retinal neurons provides an alternative route for delivery of visual information. We demonstrate that subretinal arrays with 70 μm photovoltaic pixels provide highly localized stimulation, with electrical and visual receptive fields of comparable sizes in rat retinal ganglion cells. Similarly to normal vision, retinal response to prosthetic stimulation exhibits flicker fusion at high frequencies, adaptation to static images and non-linear spatial summation. In rats with retinal degeneration, these photovoltaic arrays provide spatial resolution of 64 ± 11 μm, corresponding to half of the normal visual acuity in pigmented rats. Ease of implantation of these wireless and modular arrays, combined with their high resolution opens the door to functional restoration of sight. PMID:25915832

  5. Photovoltaic cell with light trapping for enhanced efficiency

    SciTech Connect

    Brener, Igal; Fofang, Nche Tumasang; Luk, Ting S.

    2015-11-19

    The efficiency of a photovoltaic cell is enhanced by light trapping using Mie-scattering nanostructures. In one embodiment, an array of nanocylinders is formed on the front surface of a silicon film to enhance forward scattering into the film, and an array of nanocylinders is formed on the back surface to enhance backscattering so that more light is absorbed within the silicon film. In an alternate embodiment, a mirror layer is formed on the back surface of the silicon film to reflect light within the film back toward the front-surface nanocylinder array.

  6. A photovoltaic-powered water electrolyzer - Its performance and economics

    NASA Astrophysics Data System (ADS)

    Hancock, O. G., Jr.

    A prototype water electrolyzer designed to operate from a solar photovoltaic (PV) array without power conditioning was operated for three months at the Florida Solar Energy Center. A 1 kWpk PV array was used to operate the electrolyzer at internal gas pressure from 0 to 40 psig. Performance of the elecrolyzer/PV array was measured and characterized in terms of charge efficiency and power efficiency calculated from the operation data. The economics of residential production of hydrogen for energy purposes were calculated and summarized. While the near-term outlook for this energy storage technique was not found to be favorable, the long-term outlook was encouraging.

  7. Core-shell GaN-ZnO moth-eye nanostructure arrays grown on a-SiO2/Si (1 1 1) as a basis for improved InGaN-based photovoltaics and LEDs

    NASA Astrophysics Data System (ADS)

    Rogers, D. J.; Sandana, V. E.; Gautier, S.; Moudakir, T.; Abid, M.; Ougazzaden, A.; Teherani, F. Hosseini; Bove, P.; Molinari, M.; Troyon, M.; Peres, M.; Soares, Manuel J.; Neves, A. J.; Monteiro, T.; McGrouther, D.; Chapman, J. N.; Drouhin, H.-J.; McClintock, R.; Razeghi, M.

    2015-06-01

    Self-forming, vertically-aligned, ZnO moth-eye-like nanoarrays were grown by catalyst-free pulsed laser deposition on a-SiO2/Si (1 1 1) substrates. X-Ray Diffraction (XRD) and Cathodoluminescence (CL) studies indicated that nanostructures were highly c-axis oriented wurtzite ZnO with strong near band edge emission. The nanostructures were used as templates for the growth of non-polar GaN by metal organic vapor phase epitaxy. XRD, scanning electron microscopy, energy dispersive X-ray microanalysis and CL revealed ZnO encapsulated with GaN, without evidence of ZnO back-etching. XRD showed compressive epitaxial strain in the GaN, which is conducive to stabilization of the higher indium contents required for more efficient green light emitting diode (LED) and photovoltaic (PV) operation. Angular-dependent specular reflection measurements showed a relative reflectance of less than 1% over the wavelength range of 400-720 nm at all angles up to 60°. The superior black-body performance of this moth-eye-like structure would boost LED light extraction and PV anti-reflection performance compared with existing planar or nanowire LED and PV morphologies. The enhancement in core conductivity, provided by the ZnO, would also improve current distribution and increase the effective junction area compared with nanowire devices based solely on GaN.

  8. Measurement requirements and techniques for degradation studies and lifetime prediction testing of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Noel, G. T.; Sliemers, F. A.; Derringer, G. C.; Wood, V. E.; Wilkes, K. E.; Gaines, G. B.; Carmichael, D. C.

    1978-01-01

    Tests of weathering and aging behavior are being developed to characterize the degradation and predict the lifetimes of low-cost photovoltaic arrays. Environmental factors which affect array performance include UV radiation, thermal energy, water, oxygen (generally involved in synergistic effects with UV radiation or high temperatures), physical stress, pollutants (oxides of nitrogen, sulfur dioxide and ozone), abrasives and dirt. A survey of photovoltaic array testing has shown the need to establish quantitative correlations between certain measurable properties (carbonyl formation, glass transition temperature, and molecular weight change) and modes of degradation and failure.

  9. A status report:. FACT - a fact!

    NASA Astrophysics Data System (ADS)

    Bretz, T.; Anderhub, H.; Backes, M.; Biland, A.; Boller, A.; Braun, I.; Commichau, V.; Djambazov, L.; Dorner, D.; Farnier, C.; Gendotti, A.; Grimm, O.; von Gunten, H. P.; Hildebrand, D.; Horisberger, U.; Huber, B.; Kim, K.-S.; Köhne, J.-H.; Krähenbühl, T.; Krumm, B.; Lee, M.; Lenain, J.-P.; Lorenz, E.; Lustermann, W.; Lyard, E.; Mannheim, K.; Meharga, M.; Neise, D.; Nessi-Tedaldi, F.; Overkemping, A.-K.; Pauss, F.; Renker, D.; Rhode, W.; Ribordy, M.; Rohlfs, R.; Röser, U.; Stucki, J.-P.; Schneider, J.; Thaele, J.; Tibolla, O.; Viertel, G.; Vogler, P.; Walter, R.; Warda, K.; Weitzel, Q.

    2012-08-01

    In the past years, the second generation of imaging air-Cherenkov telescopes has proven its power detecting weak sources with high sensitivity and low energy threshold. The goal to further improve the sensitivity and lower the energy threshold requires a robust and hlghly efficient sensor technology. A promising detector technology are silicon based photon detectors, namely Geiger-mode avalanche photo-diodes (G-APDs). They promise robustness and easy manage-ability compared photo-multiplier tubes so far in use. To prove the applicability of this technology for Cherenkov telescopes, one of the former HEGRA telescopes was revived and equipped with a camera using G-APDs all photo sensors. Since G-APDs are comparably small, solid light guides are used to significantly increase the light collection area of each sensor. With this technologies, the First G-APD Cherenkov Telescopes (FACT) promises an increase in sensitivity and decrease in energy threshold, compared with a classical photo-multiplier based camera.

  10. Intermediate photovoltaic system application experiment operational executive summary. Volume 3. For Lovington Square Shopping Center, Lovington, NM

    SciTech Connect

    Not Available

    1981-10-01

    For the month of August 1981, daily and monthly electricity production and daily, monthly insolation and monthly array efficiency are given for a 100 kW photovoltaic flat panel facility at a New Mexico shopping center. (LEW)

  11. Intermediate photovoltaic system application experiment operational executive summary. Volume 2. For Lovington Square Shopping Center, Lovington, NM

    SciTech Connect

    Not Available

    1981-10-01

    For the month of July 1981, the daily and monthly insolation, daily and monthly electricity production, and monthly array efficiency are given for a 100 kW photovoltaic flat panel facility at a New Mexico shopping center. (LEW)

  12. Energy Facts, 1992

    SciTech Connect

    Not Available

    1993-10-29

    Energy Facts, organized by energy source, is a compilation of energy data providing a reference to a broad range of domestic and international energy data, for the general public as well as the technical community. This report is designed especially for the business person, government worker, or student who needs a quick reference to major facts about energy. Each table of statistics appears on the opposite page from a corresponding graphic. The graphic has a point of interest rather than a title across the top.

  13. Facts in artifacts

    PubMed Central

    Bindhu, PR; Krishnapillai, Rekha; Thomas, Priya; Jayanthi, P

    2013-01-01

    Examination of microscopic sections of animal tissues reveals facts which are not always related to its normal histology or pathology. Processing of tissue specimens consists of lengthy procedures from the stage of surgical removal to the stained and mounted microscopic sections. Defects are common in tissue sections as a result of faulty procedures. These defects are referred to as artifacts. They lead to misinterpretation of histopathological diagnosis but at times they throw limelight into diagnosis. This paper attempts to put together all the facts regarding the various artifacts that are encountered in histopathology. PMID:24574659

  14. Facts in artifacts.

    PubMed

    Bindhu, Pr; Krishnapillai, Rekha; Thomas, Priya; Jayanthi, P

    2013-09-01

    Examination of microscopic sections of animal tissues reveals facts which are not always related to its normal histology or pathology. Processing of tissue specimens consists of lengthy procedures from the stage of surgical removal to the stained and mounted microscopic sections. Defects are common in tissue sections as a result of faulty procedures. These defects are referred to as artifacts. They lead to misinterpretation of histopathological diagnosis but at times they throw limelight into diagnosis. This paper attempts to put together all the facts regarding the various artifacts that are encountered in histopathology.

  15. Aeolian Removal of Dust Types from Photovoltaic Surfaces on Mars

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Perez-Davis, Marla E.; Marabito, Mark

    1990-01-01

    Dust elevated in local or global dust storms on the Martian surface could settle on photovoltaic (PV) surfaces and seriously hamper their performance. Using a recently developed technique to apply a uniform dust layer, PV surface materials were subjected to simulated Martian winds in an attempt to determine whether natural Aeolian processes on Mars would sweep off the settled dust. Three different types of dust were used; an optical polishing powder, basaltic "trap rock", and iron (III) oxide crystals. The effects of wind velocity, angle of attack, height above the Martian surface, and surface coating material were investigated. It was found that arrays mounted with an angle of attack approaching 45 degrees show the most efficient clearing. Although the angular dependence is not sharp, horizontally mounted arrays required significantly higher wind velocities to clear off the dust. From this test it appears that the arrays may be erected quite near the ground, but previous studies have suggested that saltation effects can be expected to cause such arrays to be covered by soil if they are set up less than about a meter from the ground. Particle size effects appear to dominate over surface chemistry in these experiments, but additional tests are required to confirm this. Providing that the surface chemistry of Martian dusts is not drastically different from simulated dust and that gravity differences have only minor effects, the materials used for protective coatings for photovoltaic arrays may be optimized for other considerations such as transparency, and chemical or abrasion resistance. The static threshold velocity is low enough that there are regions on Mars which experience winds strong enough to clear off a photovoltaic array if it is properly oriented. Turbulence fences proved to be an ineffective strategy to keep dust cleared from the photovoltaic surfaces.

  16. Interim performance criteria for photovoltaic energy systems. [Glossary included

    SciTech Connect

    DeBlasio, R.; Forman, S.; Hogan, S.; Nuss, G.; Post, H.; Ross, R.; Schafft, H.

    1980-12-01

    This document is a response to the Photovoltaic Research, Development, and Demonstration Act of 1978 (P.L. 95-590) which required the generation of performance criteria for photovoltaic energy systems. Since the document is evolutionary and will be updated, the term interim is used. More than 50 experts in the photovoltaic field have contributed in the writing and review of the 179 performance criteria listed in this document. The performance criteria address characteristics of present-day photovoltaic systems that are of interest to manufacturers, government agencies, purchasers, and all others interested in various aspects of photovoltaic system performance and safety. The performance criteria apply to the system as a whole and to its possible subsystems: array, power conditioning, monitor and control, storage, cabling, and power distribution. They are further categorized according to the following performance attributes: electrical, thermal, mechanical/structural, safety, durability/reliability, installation/operation/maintenance, and building/site. Each criterion contains a statement of expected performance (nonprescriptive), a method of evaluation, and a commentary with further information or justification. Over 50 references for background information are also given. A glossary with definitions relevant to photovoltaic systems and a section on test methods are presented in the appendices. Twenty test methods are included to measure performance characteristics of the subsystem elements. These test methods and other parts of the document will be expanded or revised as future experience and needs dictate.

  17. Design of photovoltaic systems for residential applications

    NASA Astrophysics Data System (ADS)

    Jones, G. J.

    1981-04-01

    Advantages and limitations of the potential residential photovoltaic system market and the impact of recent studies on future designs are reviewed. Typical system configurations are projected based on the existence of ideal rate structures and utility interactive operation. Sizing tradeoffs are analyzed in detail showing that systems from 3 kW/sub p/ to 10 kW/sub p/ are probable. Based on load considerations, development of 4 kW/sub p/ and 8 kW/sub p/ systems is suggested. The impact of this choice on array sizing as a function of site is discussed.

  18. Space Photovoltaic Research and Technology, 1989

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Remarkable progress on a wide variety of approaches in space photovoltaics, for both near and far term applications is reported. Papers were presented in a variety of technical areas, including multi-junction cell technology, GaAs and InP cells, system studies, cell and array development, and non-solar direct conversion. Five workshops were held to discuss the following topics: mechanical versus monolithic multi-junction cells; strategy in space flight experiments; non-solar direct conversion; indium phosphide cells; and space cell theory and modeling.

  19. Photovoltaic Power for Future NASA Missions

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey; Bailey, Sheila G.; Lyons, Valerie J. (Technical Monitor)

    2002-01-01

    Recent advances in crystalline solar cell technology are reviewed. Dual-junction and triple-junction solar cells are presently available from several U. S. vendors. Commercially available triple-junction cells consisting of GaInP, GaAs, and Ge layers can produce up to 27% conversion efficiency in production lots. Technology status and performance figures of merit for currently available photovoltaic arrays are discussed. Three specific NASA mission applications are discussed in detail: Mars surface applications, high temperature solar cell applications, and integrated microelectronic power supplies for nanosatellites.

  20. Parabolic dish photovoltaic concentrator development

    NASA Astrophysics Data System (ADS)

    Beninga, K.; Davenport, R.; Featherby, M.; Sandubrae, J.; Walcott, K.

    1991-05-01

    Science Applications International Corporation (SAIC) and Tactical Fabs, Inc. (TFI) have fabricated a prototype parabolic dish photovoltaic (PV) concentrator system to demonstrate the functionality of this approach. A 1.5 m diameter parabolic dish was fabricated of a polyester/fiberglass composite, with a silvered polymer reflective surface. An innovative receiver cooling system used outward radial flow of cooling water in a narrow passage. This configuration matches the heat transfer capability of the cooling system to the flux profile on the PV receiver, minimizing temperature variations across the receiver. The photovoltaic cells used in the system were a new, TFI-proprietary design. Interleaved contacts form a bi-polar, rear-contact cell configuration. Because the electrical contacts are made on the rear of the cells, cells can be close-packed to form receiver arrays of arbitrary shape and size. Optical testing of the dish concentrator was performed by SAIC, SERI, and Sandia National Labs. The dish concentrator, designed for solar thermal applications, had a tight focal spot but exhibited flux non-uniformities away from the focal plane. Thermal testing of the receiver cooling system was performed with excellent success. Single PV cells, 4-cell blocks, and 144-cell receiver modules were built and tested. The cells successfully demonstrated the TFI design concept, but due to cell processing problems their efficiency was very low. Sources of the processing problems were identified and solutions were proposed, but funding limitations precluded further cell production. Operation of the complete PV dish system was conducted, and the functionality of the system was demonstrated. However, low cell efficiencies and receiver plane flux non-uniformities caused the system performance to be very low. These problems are not generic to the concept, and solutions to them proposed.

  1. High-performance, flexible, deployable array development for space applications

    NASA Technical Reports Server (NTRS)

    Gehling, Russell N.; Armstrong, Joseph H.; Misra, Mohan S.

    1994-01-01

    Flexible, deployable arrays are an attractive alternative to conventional solar arrays for near-term and future space power applications, particularly due to their potential for high specific power and low storage volume. Combined with low-cost flexible thin-film photovoltaics, these arrays have the potential to become an enabling or an enhancing technology for many missions. In order to expedite the acceptance of thin-film photovoltaics for space applications, however, parallel development of flexible photovoltaics and the corresponding deployable structure is essential. Many innovative technologies must be incorporated in these arrays to ensure a significant performance increase over conventional technologies. For example, innovative mechanisms which employ shape memory alloys for storage latches, deployment mechanisms, and array positioning gimbals can be incorporated into flexible array design with significant improvement in the areas of cost, weight, and reliability. This paper discusses recent activities at Martin Marietta regarding the development of flexible, deployable solar array technology. Particular emphasis is placed on the novel use of shape memory alloys for lightweight deployment elements to improve the overall specific power of the array. Array performance projections with flexible thin-film copper-indium-diselenide (CIS) are presented, and government-sponsored solar array programs recently initiated at Martin Marietta through NASA and Air Force Phillips Laboratory are discussed.

  2. Kokkos Array

    SciTech Connect

    Edwards Daniel Sunderland, Harold Carter

    2012-09-12

    The Kokkos Array library implements shared-memory array data structures and parallel task dispatch interfaces for data-parallel computational kernels that are performance-portable to multicore-CPU and manycore-accelerator (e.g., GPGPU) devices.

  3. Benchmarking concentrating photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Duerr, Fabian; Muthirayan, Buvaneshwari; Meuret, Youri; Thienpont, Hugo

    2010-08-01

    Integral to photovoltaics is the need to provide improved economic viability. To achieve this goal, photovoltaic technology has to be able to harness more light at less cost. A large variety of concentrating photovoltaic concepts has provided cause for pursuit. To obtain a detailed profitability analysis, a flexible evaluation is crucial for benchmarking the cost-performance of this variety of concentrating photovoltaic concepts. To save time and capital, a way to estimate the cost-performance of a complete solar energy system is to use computer aided modeling. In this work a benchmark tool is introduced based on a modular programming concept. The overall implementation is done in MATLAB whereas Advanced Systems Analysis Program (ASAP) is used for ray tracing calculations. This allows for a flexible and extendable structuring of all important modules, namely an advanced source modeling including time and local dependence, and an advanced optical system analysis of various optical designs to obtain an evaluation of the figure of merit. An important figure of merit: the energy yield for a given photovoltaic system at a geographical position over a specific period, can be calculated.

  4. Photovoltaic and thermal energy conversion for solar powered satellites

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G. F.

    1976-01-01

    A summary is provided concerning the most important aspects of present investigations related to a use of solar power satellites (SPS) as a future source of terrestrial energy. General SPS characteristics are briefly considered, early work is reviewed, and a description of current investigations is presented. System options presently under study include a photovoltaic array, a thermionic system, and a closed Brayton cycle. Attention is given to system reference options, basic building blocks, questions of system analysis and engineering, photovoltaic conversion, and the utility interface. It is concluded that an SPS may be cost effective compared to terrestrial systems by 1995.

  5. 205 kW Photovoltaic (PV) System Installed on the U.S. Department of Energy's Forrestal Building

    SciTech Connect

    2009-01-18

    Fact sheet on the installation of a photovoltaic system providing renewable energy for the U.S. Department of Energy and providing leadership for meeting Federal goals in the use of renewable energy technologies.

  6. Systolic arrays

    SciTech Connect

    Moore, W.R.; McCabe, A.P.H.; Vrquhart, R.B.

    1987-01-01

    Selected Contents of this book are: Efficient Systolic Arrays for the Solution of Toeplitz Systems, The Derivation and Utilization of Bit Level Systolic Array Architectures, an Efficient Systolic Array for Distance Computation Required in a Video-Codec Based Motion-Detection, On Realizations of Least-Squares Estimation and Kalman Filtering by Systolic Arrays, and Comparison of Systolic and SIMD Architectures for Computer Vision Computations.

  7. Nanocylinder arrays

    DOEpatents

    Tuominen, Mark; Schotter, Joerg; Thurn-Albrecht, Thomas; Russell, Thomas P.

    2009-08-11

    Pathways to rapid and reliable fabrication of nanocylinder arrays are provided. Simple methods are described for the production of well-ordered arrays of nanopores, nanowires, and other materials. This is accomplished by orienting copolymer films and removing a component from the film to produce nanopores, that in turn, can be filled with materials to produce the arrays. The resulting arrays can be used to produce nanoscale media, devices, and systems.

  8. Nanocylinder arrays

    DOEpatents

    Tuominen, Mark; Schotter, Joerg; Thurn-Albrecht, Thomas; Russell, Thomas P.

    2007-03-13

    Pathways to rapid and reliable fabrication of nanocylinder arrays are provided. Simple methods are described for the production of well-ordered arrays of nanopores, nanowires, and other materials. This is accomplished by orienting copolymer films and removing a component from the film to produce nanopores, that in turn, can be filled with materials to produce the arrays. The resulting arrays can be used to produce nanoscale media, devices, and systems.

  9. Intermediate photovoltaic system application experiment: operation performance executive summary. Volume 9. Lovington Square Shopping Center, Lovington, NM

    SciTech Connect

    Not Available

    1982-04-01

    Performance data are given for a 100 kW peak flat panel grid connected photovoltaic power supply at a New Mexico shopping center for the month of March, 1982. Data include: daily and monthly electrical energy produced by the array field, daily and monthly incident solar energy in the plane of the collector, array efficiency, power conditioner efficiency, photovoltaic system efficiency, capacity factor, and insolation. Also included is a data acquisition mode and recording interval plot for the month. (LEW)

  10. Disease Prevention. Health Facts.

    ERIC Educational Resources Information Center

    Stang, Lucas; Miner, Kathleen R.

    The 10-volume "Health Facts" series is intended to supplement health education curricula and to provide a handy reference for individuals who would like additional background information on particular health topics. The emphasis is placed on topics and examples relevant to youth of middle and high school age. The five sections in this book on…

  11. Sexuality. Health Facts.

    ERIC Educational Resources Information Center

    Stang, Lucas; Miner, Kathleen R.

    The 10-volume "Health Facts" series is intended to supplement health education curricula and provide a handy reference for individuals who would like additional background information on particular health topics. The emphasis is placed on topics and examples relevant to youth of middle and high school age. The seven sections in this book on…

  12. 2012 BC Education Facts

    ERIC Educational Resources Information Center

    British Columbia Teachers' Federation, 2012

    2012-01-01

    This report presents facts and figures on British Columbia's education for 2012. It is divided into the following seven sections: (1) Schools, which covers: (a) Number of public schools; (b) Number of independent (private) schools; (c) School closures; (d) Rural schools and students; (e) School-district amalgamation; and (f) School safety: Seismic…

  13. Marijuana: Facts for Teens.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHHS), Rockville, MD. Div. of Research.

    Using a question and answer format, this booklet is designed to inform teens about the dangers of marijuana usage. Inset facts about marijuana and teen perspectives compliment the following topics: (1) What is marijuana? (2) How is marijuana used? (3) How long does marijuana stay in the user's body? (4) How many teens smoke marijuana? (5) Why do…

  14. Nutrition. Health Facts.

    ERIC Educational Resources Information Center

    Stang, Lucas; Miner, Kathleen R.

    The 10-volume "Health Facts" series is intended to supplement to health education curricula and provide a handy reference for individuals who would like additional background information on particular health topics. The emphasis is on topics and examples relevant to youth of middle and high school age. The five sections in this book provide…

  15. Nuclear fact book

    SciTech Connect

    Hill, O. F.; Platt, A. M.; Robinson, J. V.

    1983-05-01

    This reference provides significant highlights and summary facts in the following areas: general energy; nuclear energy; nuclear fuel cycle; uranium supply and enrichment; nuclear reactors; spent fuel and advanced repacking concepts; reprocessing; high-level waste; gaseous waste; transuranic waste; low-level waste; remedial action; transportation; disposal; radiation information; environment; legislation; socio-political aspects; conversion factors; and a glossary. (GHT)

  16. NASA Facts, The Countdown.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    This pamphlet describes the preparations for launching a giant Atlas, Gemini (Titan 11), or Saturn launch vehicle. The material is intended for use in elementary general science. The pamphlet is one of the NASA Facts Science Series (each of which consists of four pages) and is designed to fit in the standard size three-ring notebook. Review…

  17. NASA Facts, Voyager.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC. Educational Programs Div.

    This document is one of a series of publications of the National Aeronautics and Space Administration (NASA) on facts about the exploration of Jupiter and Saturn. This NASA mission consists of two unmanned Voyager spacecrafts launched in August and September of 1977, and due to arrive at Jupiter in 1979. An account of the scientific equipment…

  18. Ethanol Myths Fact Sheet

    SciTech Connect

    2009-10-27

    Ethanol is a clean, renewable fuel that is helping to reduce our nation’s dependence on oil and can offer additional economic and environmental benefits in the future. This fact sheet is intended to address some common misconceptions about this important alternative fuel.

  19. Energy Facts 1988.

    ERIC Educational Resources Information Center

    Energy Information Administration (DOE), Washington, DC.

    This booklet is a compilation of energy data providing a reference to a much broader range of domestic and international energy data. It is designed especially as a quick reference to major facts about energy. The data includes information for 1976 through 1988, except for international energy data, which is for 1977 through 1987. Graphs, charts,…

  20. Gun Sales. Firearm Facts.

    ERIC Educational Resources Information Center

    Duker, Laurie, Ed.

    Minimal federal regulations on firearm sales have facilitated the proliferation of guns, gun owners, and gun dealers in the United States. This fact sheet offers data on the growing number of firearm dealers, the relative ease of obtaining and keeping a license to sell guns from the Federal Bureau of Alcohol, Tobacco, and Firearms, the lack of…

  1. Insulation Fact Sheet.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    Heating and cooling account for 50-70% of the energy consumed in the average American home. Heating water accounts for another 20%. A poorly insulated home loses much of this energy, causing drafty rooms and high energy bills. This fact sheet discusses how to determine if your home needs more insulation, the additional thermal resistance (called…

  2. Blood Facts and Statistics

    MedlinePlus

    ... Back to Top Facts about the blood donation process Donating blood is a safe process. A sterile needle is used only once for ... discarded. Blood donation is a simple four-step process: registration, medical history and mini-physical, donation and ...

  3. Ethanol Basics (Fact Sheet)

    SciTech Connect

    Not Available

    2015-01-01

    Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

  4. Facts about Birth Defects

    MedlinePlus

    ... Us Information For... Media Policy Makers Facts about Birth Defects Language: English Español (Spanish) Recommend on Facebook Tweet ... having a baby born without a birth defect. Birth Defects Are Common Every 4 ½ minutes, a baby ...

  5. Algal Biofuels Fact Sheet

    SciTech Connect

    2009-10-27

    This fact sheet provides information on algal biofuels, which are generating considerable interest around the world. They may represent a sustainable pathway for helping to meet the U.S. biofuel production targets set by the Energy Independence and Security Act of 2007.

  6. HIV Prevention. Health Facts.

    ERIC Educational Resources Information Center

    Stang, Lucas; Miner, Kathleen R.

    The 10-volume "Health Facts" series is intended to supplement health education curricula and provide a handy reference for individuals who would like additional background information on particular health topics. The emphasis is placed on topics and examples relevant to youth of middle and high school age. The seven sections in this book provide…

  7. Facts about Antibiotic Resistance

    MedlinePlus

    ... Trends and Cost Español: Datos breves Facts about Antibiotic Resistance Antibiotic resistance has been called one of the world’s most ... antibiotic use is a key strategy to control antibiotic resistance. Antibiotic resistance in children is of particular concern ...

  8. NASA Facts, Solar Cells.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    The design and function of solar cells as a source of electrical power for unmanned space vehicles is described in this pamphlet written for high school physical science students. The pamphlet is one of the NASA Facts Science Series (each of which consists of four pages) and is designed to fit in the standard size three-ring notebook. Review…

  9. Bat Facts and Fun.

    ERIC Educational Resources Information Center

    McKee, Judith A.

    1992-01-01

    Describes a unit of study for elementary school science on bats. Students investigate the different types of bats; examine their behavior; find facts that other students are unlikely to know; write stories about bats; and examine the concept of echolocation, the means by which bats navigate. Suggests integrated activities for mathematics…

  10. Trauma Facts for Educators

    ERIC Educational Resources Information Center

    National Child Traumatic Stress Network, 2008

    2008-01-01

    This paper offers facts which can help educators deal with children undergoing trauma. These include: (1) One out of every 4 children attending school has been exposed to a traumatic event that can affect learning and/or behavior; (2) Trauma can impact school performance; (3) Trauma can impair learning; (4) Traumatized children may experience…

  11. Mastering the Multiplication Facts

    ERIC Educational Resources Information Center

    D'Ettorre, Jenna

    2009-01-01

    The purpose of this paper is to share the results of a six-week research project (after baseline data was collected) that focused on three different strategies (flashcards, interactive games, and music) and their effectiveness in helping fifth grade students memorize the basic multiplication facts. Many teachers face a serious problem when their…

  12. STD Prevention. Health Facts.

    ERIC Educational Resources Information Center

    Stang, Lucas; Miner, Kathleen R.

    The 10-volume "Health Facts" series is intended to supplement health education curricula and provide a handy reference for individuals who would like additional background information on particular health topics. The emphasis is placed on topics and examples relevant to youth of middle and high school age. The five sections in this book provide…

  13. Interconnect fatigue design for terrestrial photovoltaic modules

    SciTech Connect

    Mon, G. R.; Moore, D. M.; Ross, Jr., R. G.

    1982-03-01

    Fatigue of solar cell electrical interconnects due to thermal cycling has historically been a major failure mechanism in photovoltaic arrays; the results of a comprehensive investigation of interconnect fatigue that has led to the definition of useful reliability-design and life-prediction algorithms are presented. Experimental data gathered in this study indicate that the classical strain-cycle (fatigue) curve for the interconnect material is a good model of mean interconnect fatigue performance, but it fails to account for the broad statistical scatter, which is critical to reliability prediction. To fill this shortcoming the classical fatigue curve is combined with experimental cumulative interconnect failure rate data to yield statistical fatigue curves (having failure probability as a parameter) which enable: (1) the prediction of cumulative interconnect failures during the design life of an array field; and (2) the unambiguous - i.e., quantitative - interpretation of data from field-service qualification (accelerated thermal cycling) tests. Optimal interconnect cost-reliability design algorithms are derived based on minimizing the cost of energy over the design life of the array field. This procedure yields not only the minimum break-even cost of delivered energy, but also the required degree of interconnect redundancy and an estimate of array power degradation during the design life of the array field. The usefulness of the design algorithms is demonstrated with realistic examples of design optimization, prediction, and service qualification testing.

  14. Definition study for photovoltaic residential prototype system

    NASA Technical Reports Server (NTRS)

    Imamura, M. S.; Hulstrom, R. L.; Cookson, C.; Waldman, B. H.; Lane, R. A.

    1976-01-01

    A parametric sensitivity study and definition of the conceptual design is presented. A computer program containing the solar irradiance, solar array, and energy balance models was developed to determine the sensitivities of solar insolation and the corresponding solar array output at five sites selected for this study as well as the performance of several solar array/battery systems. A baseline electrical configuration was chosen, and three design options were recommended. The study indicates that the most sensitive parameters are the solar insolation and the inverter efficiency. The baseline PST selected is comprised of a 133 sg m solar array, 250 ampere hour battery, one to three inverters, and a full shunt regulator to limit the upper solar array voltage. A minicomputer controlled system is recommended to provide the overall control, display, and data acquisition requirements. Architectural renderings of two photovoltaic residential concepts, one above ground and the other underground, are presented. The institutional problems were defined in the areas of legal liabilities during and after installation of the PST, labor practices, building restrictions and architectural guides, and land use.

  15. Nanowires enabling strained photovoltaics

    SciTech Connect

    Greil, J.; Bertagnolli, E.; Lugstein, A.; Birner, S.

    2014-04-21

    Photovoltaic nano-devices have largely been relying on charge separation in conventional p-n junctions. Junction formation via doping, however, imposes major challenges in process control. Here, we report on a concept for photovoltaic energy conversion at the nano scale without the need for intentional doping. Our approach relies on charge carrier separation in inhomogeneously strained germanium nanowires (Ge NWs). This concept utilizes the strain-induced gradient in bandgap along tapered NWs. Experimental data confirms the feasibility of strain-induced charge separation in individual vapor-liquid-solid grown Ge NW devices with an internal quantum efficiency of ∼5%. The charge separation mechanism, though, is not inherently limited to a distinct material. Our work establishes a class of photovoltaic nano-devices with its opto-electronic properties engineered by size, shape, and applied strain.

  16. Photovoltaic Subcontract Program

    SciTech Connect

    Surek, Thomas; Catalano, Anthony

    1993-03-01

    This report summarizes the fiscal year (FY) 1992 progress of the subcontracted photovoltaic (PV) research and development (R D) performed under the Photovoltaic Advanced Research and Development Project at the National Renewable Energy Laboratory (NREL)-formerly the Solar Energy Research Institute (SERI). The mission of the national PV program is to develop PV technology for large-scale generation of economically competitive electric power in the United States. The technical sections of the report cover the main areas of the subcontract program: the Crystalline Materials and Advanced Concepts project, the Polycrystalline Thin Films project, Amorphous Silicon Research project, the Photovoltaic Manufacturing Technology (PVMaT) project, PV Module and System Performance and Engineering project, and the PV Analysis and Applications Development project. Technical summaries of each of the subcontracted programs provide a discussion of approaches, major accomplishments in FY 1992, and future research directions.

  17. Designing future photovoltaic systems

    SciTech Connect

    Jones, G.J.

    1984-01-01

    The large scale use of photovoltaic systems to generate our electricity is a dream for the future; but if this dream is to be realized, we must understand these systems today. As a result, there has been extensive research into the design and economic tradeoffs of utility interconnected photovoltaic applications. The understanding gained in this process has shown that photovoltaic system design can be a very simple and straight-forward endeavor. This paper reviews those past studies and shows how we have reached the present state of system design evolution. The concept of the utility interactive PV system with energy value determined by the utility's avoided cost will be explored. This concept simplifies the screening of potential applications for economic viability, and we will present several rules-of-thumb for this purpose.

  18. LSA Low-cost Solar Array project

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The activities of the Low-Cost Silicon Solar Array Project during the period October through December, 1977 are reported. The LSSA Project is assigned responsibility for advancing silicon solar array technology while encouraging industry to reduce the price of arrays to a level at which photovoltaic electric power systems will be competitive with more conventional power sources early in the next decade. Set forth are the goals and plans with which the Project intends to accomplish this and the progress that was made during the quarter.

  19. Low-cost Solar Array (LSA) project

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The activities of the Low-Cost Solar Array Project are described for the period April through June 1978. The Project is assigned responsibility for advancing solar array technology while encouraging industry to reduce the price of arrays to a level at which photovoltaic electric power systems will be competitive with more conventional power sources early in the next decade. Set forth are the goals and plans with which the Project intends to accomplish this and the progress that was made during the quarter.

  20. Physics of Quantum Structures in Photovoltaic Devices

    NASA Technical Reports Server (NTRS)

    Raffaelle, Ryne P.; Andersen, John D.

    2005-01-01

    There has been considerable activity recently regarding the possibilities of using various nanostructures and nanomaterials to improve photovoltaic conversion of solar energy. Recent theoretical results indicate that dramatic improvements in device efficiency may be attainable through the use of three-dimensional arrays of zero-dimensional conductors (i.e., quantum dots) in an ordinary p-i-n solar cell structure. Quantum dots and other nanostructured materials may also prove to have some benefits in terms of temperature coefficients and radiation degradation associated with space solar cells. Two-dimensional semiconductor superlattices have already demonstrated some advantages in this regard. It has also recently been demonstrated that semiconducting quantum dots can also be used to improve conversion efficiencies in polymeric thin film solar cells. Improvement in thin film cells utilizing conjugated polymers has also be achieved through the use of one-dimensional quantum structures such as carbon nanotubes. It is believed that carbon nanotubes may contribute to both the disassociation as well as the carrier transport in the conjugated polymers used in certain thin film photovoltaic cells. In this paper we will review the underlying physics governing some of the new photovoltaic nanostructures being pursued, as well as the the current methods being employed to produce III-V, II-VI, and even chalcopyrite-based nanomaterials and nanostructures for solar cells.

  1. White butterflies as solar photovoltaic concentrators

    NASA Astrophysics Data System (ADS)

    Shanks, Katie; Senthilarasu, S.; Ffrench-Constant, Richard H.; Mallick, Tapas K.

    2015-07-01

    Man’s harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies’ wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies’ thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off.

  2. White butterflies as solar photovoltaic concentrators

    PubMed Central

    Shanks, Katie; Senthilarasu, S.; ffrench-Constant, Richard H.; Mallick, Tapas K.

    2015-01-01

    Man’s harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies’ wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies’ thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off. PMID:26227341

  3. White butterflies as solar photovoltaic concentrators.

    PubMed

    Shanks, Katie; Senthilarasu, S; Ffrench-Constant, Richard H; Mallick, Tapas K

    2015-07-31

    Man's harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies' wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies' thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off.

  4. White butterflies as solar photovoltaic concentrators.

    PubMed

    Shanks, Katie; Senthilarasu, S; Ffrench-Constant, Richard H; Mallick, Tapas K

    2015-01-01

    Man's harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies' wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies' thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off. PMID:26227341

  5. The DOE photovoltaics program

    NASA Technical Reports Server (NTRS)

    Ferber, R. R.

    1983-01-01

    The considered program of the U.S. Department of Energy (DOE) has the objective to provide federal support for research and development work related to photovoltaics. According to definitions of policy in 1981, a strong emphasis is to be placed on long-term, high-risk research and development that industry could not reasonably be expected to perform using their own funds. Attention is given to the program structure, the photovoltaics program management organization, the advanced research and development subprogram, the collector research and development subprogram, flat-plate collectors, concentrator collectors, and the systems research and technology subprogram.

  6. Asphaltene based photovoltaic devices

    DOEpatents

    Chianelli, Russell R.; Castillo, Karina; Gupta, Vipin; Qudah, Ali M.; Torres, Brenda; Abujnah, Rajib E.

    2016-03-22

    Photovoltaic devices and methods of making the same, are disclosed herein. The cell comprises a photovoltaic device that comprises a first electrically conductive layer comprising a photo-sensitized electrode; at least one photoelectrochemical layer comprising metal-oxide particles, an electrolyte solution comprising at least one asphaltene fraction, wherein the metal-oxide particles are optionally dispersed in a surfactant; and a second electrically conductive layer comprising a counter-electrode, wherein the second electrically conductive layer comprises one or more conductive elements comprising carbon, graphite, soot, carbon allotropes or any combinations thereof.

  7. Three-dimensional photovoltaics

    NASA Astrophysics Data System (ADS)

    Myers, Bryan; Bernardi, Marco; Grossman, Jeffrey C.

    2010-02-01

    The concept of three-dimensional (3D) photovoltaics is explored computationally using a genetic algorithm to optimize the energy production in a day for arbitrarily shaped 3D solar cells confined to a given area footprint and total volume. Our simulations demonstrate that the performance of 3D photovoltaic structures scales linearly with height, leading to volumetric energy conversion, and provides power fairly evenly throughout the day. Furthermore, we show that optimal 3D structures are not simple box-like shapes, and that design attributes such as reflectivity could be optimized using three-dimensionality.

  8. Three-dimensional photovoltaics

    NASA Astrophysics Data System (ADS)

    Myers, Bryan; Bernardi, Marco; Grossman, Jeffrey C.

    2010-03-01

    The concept of three-dimensional (3D) photovoltaics is explored computationally using a genetic algorithm to optimize the energy production in a day for arbitrarily shaped 3D solar cells confined to a given area footprint and total volume. Our simulations demonstrate that the performance of 3D photovoltaic structures scales linearly with height, leading to volumetric energy conversion, and provides power fairly evenly throughout the day. Furthermore, we show that optimal 3D shapes are not simple box-like shapes, and that design attributes such as reflectivity can be optimized in new ways using three-dimensionality.

  9. Concentrating photovoltaic solar panel

    DOEpatents

    Cashion, Steven A; Bowser, Michael R; Farrelly, Mark B; Hines, Braden E; Holmes, Howard C; Johnson, Jr., Richard L; Russell, Richard J; Turk, Michael F

    2014-04-15

    The present invention relates to photovoltaic power systems, photovoltaic concentrator modules, and related methods. In particular, the present invention features concentrator modules having interior points of attachment for an articulating mechanism and/or an articulating mechanism that has a unique arrangement of chassis members so as to isolate bending, etc. from being transferred among the chassis members. The present invention also features adjustable solar panel mounting features and/or mounting features with two or more degrees of freedom. The present invention also features a mechanical fastener for secondary optics in a concentrator module.

  10. High efficiency photovoltaic device

    DOEpatents

    Guha, Subhendu; Yang, Chi C.; Xu, Xi Xiang

    1999-11-02

    An N-I-P type photovoltaic device includes a multi-layered body of N-doped semiconductor material which has an amorphous, N doped layer in contact with the amorphous body of intrinsic semiconductor material, and a microcrystalline, N doped layer overlying the amorphous, N doped material. A tandem device comprising stacked N-I-P cells may further include a second amorphous, N doped layer interposed between the microcrystalline, N doped layer and a microcrystalline P doped layer. Photovoltaic devices thus configured manifest improved performance, particularly when configured as tandem devices.

  11. Effect of wind speed on performance of a solar-pv array

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thousands of solar photovoltaic (PV) arrays have been installed over the past few years, but the effect of wind speed on the predicted performance of PV arrays is not usually considered by installers. An increase in wind speed will cool the PV array, and the electrical power of the PV modules will ...

  12. Measurement of high-voltage and radiation-damage limitations to advanced solar array performance

    NASA Technical Reports Server (NTRS)

    Guidice, D. A.; Severance, P. S.; Keinhardt, K. C.

    1991-01-01

    A description is given of the reconfigured Photovoltaic Array Space Power (PASP) Plus experiment: its objectives, solar-array complement, and diagnostic sensors. Results from a successful spaceflight will lead to a better understanding of high-voltage and radiation-damage limitations in the operation of new-technology solar arrays.

  13. SERF photovoltaic systems. Technical report on system performance for the period, August 1, 1994--July 31, 1995

    SciTech Connect

    Dyk, E.E. van; Strand, T.R.; Hansen, R.

    1996-06-01

    This report presents an analysis of performance data on the two identical, 6 kW{sub ac}, grid-connected photovoltaic systems located on the roof of the Solar Energy Research Facility building at the National Renewable Energy Laboratory in Golden, Colorado. The data cover the monitoring period August 1, 1994, to July 31, 1995, and the performance parameters analyzed include direct current and alternating current power, aperture-area efficiency, energy, capacity factor, and performance index. These parameters are compared to plane-of-array irradiance, ambient temperature, and back-of-module temperature as a function of time, either daily or monthly. We also obtained power ratings of the systems for data corresponding to different test conditions. This study has shown, in addition to expected seasonal trends, that system monitoring is a valuable tool in assessing performance and detecting faulty equipment. Furthermore, methods applied for this analysis may be used to evaluate and compare systems using cells of different technologies. The systems were both found to be operating at approximately 7% below their estimated rating, which was based on Photovoltaics for Utility-Scale Applications test conditions. This may be attributed to the design inverter efficiency being estimated at 95% compared to measured values of approximately 88%, as well as the fact that aperture-area efficiency that was overestimated at 12.8% compared to a measured value of 11.0%. The continuous monitoring also revealed faulty peak-power point tracking equipment.

  14. Electric power - Photovoltaic or solar dynamic?

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Hallinan, G. J.; Hieatt, J. L.

    1985-01-01

    The design of the power system for supplying the Space Station with insolation-generated electricity is the main Phase B task at NASA-Lewis Center. The advantages and limitations of two types of power systems, the photovoltaic arrays (PV) and the solar dynamic system (SD), are discussed from the points of view of cost, overall systems integration, and growth. Subsystems of each of these options are described, and a sketch of a projected SD system is shown. The PV technology is well developed and proven, but its low efficiency calls for solar arrays of large areas, which affect station dynamics, control, and drag compensation. The SD systems would be less costly to operate than VP, and are more efficient, needing less deployed area. The major drawback of the SD is its infancy. The conservative and forgiving designs for some of its components must still be created and tested, and the development risks assessed.

  15. Clean Cities Fact Sheet

    SciTech Connect

    Not Available

    2004-01-01

    This fact sheet explains the Clean Cities Program and provides contact information for all coalitions and regional offices. It answers key questions such as: What is the Clean Cities Program? What are alternative fuels? How does the Clean Cities Program work? What sort of assistance does Clean Cities offer? What has Clean Cities accomplished? What is Clean Cities International? and Where can I find more information?

  16. Biomolecular Science (Fact Sheet)

    SciTech Connect

    Not Available

    2012-04-01

    A brief fact sheet about NREL Photobiology and Biomolecular Science. The research goal of NREL's Biomolecular Science is to enable cost-competitive advanced lignocellulosic biofuels production by understanding the science critical for overcoming biomass recalcitrance and developing new product and product intermediate pathways. NREL's Photobiology focuses on understanding the capture of solar energy in photosynthetic systems and its use in converting carbon dioxide and water directly into hydrogen and advanced biofuels.

  17. Advanced photovoltaic power system technology for lunar base applications

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Flood, Dennis J.

    1992-01-01

    The development of an advanced photovoltaic power system that would have application for a manned lunar base is currently planned under the Surface Power element of Pathfinder. Significant mass savings over state-of-the-art photovoltaic/battery systems are possible with the use of advanced lightweight solar arrays coupled with regenerative fuel cell storage. The solar blanket, using either ultrathin GaAs or amorphous silicon solar cells, would be integrated with a reduced-g structure. Regenerative fuel cells with high-pressure gas storage in filament-wound tanks are planned for energy storage. An advanced PV/RFC power system is a leading candidate for a manned lunar base as it offers a tremendous weight advantage over state-of-the-art photovoltaic/battery systems and is comparable in mass to other advanced power generation technologies.

  18. Photovoltaics in Japan

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1985-01-01

    Report surveys status of research and development on photovoltaics in Japan. Report based on literature searches, private communications, and visits by author to Japanese facilities. Included in survey are Sunshine Project, national program to develop energy sources; industrial development at private firms; and work at academic institutions.

  19. Photovoltaic radiation detector element

    DOEpatents

    Agouridis, D.C.

    1980-12-17

    A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein in the edge of which closely approaches but is spaced from the current collector strips.

  20. Formed photovoltaic module busbars

    DOEpatents

    Rose, Douglas; Daroczi, Shan; Phu, Thomas

    2015-11-10

    A cell connection piece for a photovoltaic module is disclosed herein. The cell connection piece includes an interconnect bus, a plurality of bus tabs unitarily formed with the interconnect bus, and a terminal bus coupled with the interconnect bus. The plurality of bus tabs extend from the interconnect bus. The terminal bus includes a non-linear portion.

  1. Thin film photovoltaic cell

    DOEpatents

    Meakin, John D.; Bragagnolo, Julio

    1982-01-01

    A thin film photovoltaic cell having a transparent electrical contact and an opaque electrical contact with a pair of semiconductors therebetween includes utilizing one of the electrical contacts as a substrate and wherein the inner surface thereof is modified by microroughening while being macro-planar.

  2. Photovoltaic radiation detector element

    DOEpatents

    Agouridis, Dimitrios C.

    1983-01-01

    A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein the edge of which closely approaches but is spaced from the current collector strips.

  3. Multiple gap photovoltaic device

    DOEpatents

    Dalal, Vikram L.

    1981-01-01

    A multiple gap photovoltaic device having a transparent electrical contact adjacent a first cell which in turn is adjacent a second cell on an opaque electrical contact, includes utilizing an amorphous semiconductor as the first cell and a crystalline semiconductor as the second cell.

  4. Photovoltaics reading list

    SciTech Connect

    Not Available

    1984-01-01

    The articles, conference papers, monographs and technical reports cited here are meant to provide a basic introduction to photovoltaics, its research, economics, and technology development. In addition to specific articles and books, several directories, bibliographies, journals, and magazines are suggested as additional sources of information.

  5. Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics

    NASA Astrophysics Data System (ADS)

    Price, Jared S.; Sheng, Xing; Meulblok, Bram M.; Rogers, John A.; Giebink, Noel C.

    2015-02-01

    Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels <1 cm thick that accomplish full-day tracking with >200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments.

  6. Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics.

    PubMed

    Price, Jared S; Sheng, Xing; Meulblok, Bram M; Rogers, John A; Giebink, Noel C

    2015-02-05

    Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels <1 cm thick that accomplish full-day tracking with >200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments.

  7. Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics.

    PubMed

    Price, Jared S; Sheng, Xing; Meulblok, Bram M; Rogers, John A; Giebink, Noel C

    2015-01-01

    Concentrating photovoltaics offer a way to lower the cost of solar power. However, the existing paradigm based on precise orientation of large-area concentrator modules towards the Sun limits their deployment to large, open land areas. Here, we explore an alternate approach using high-efficiency microcell photovoltaics embedded between a pair of plastic lenslet arrays to demonstrate quasi-static concentrating photovoltaic panels <1 cm thick that accomplish full-day tracking with >200x flux concentration ratio through small (<1 cm) lateral translation at fixed latitude tilt. Per unit of installed land area, cosine projection loss for fixed microtracking concentrating photovoltaic panels is ultimately offset by improved ground coverage relative to their conventional dual-axis counterparts, enabling a ~1.9x increase in daily energy output that may open up a new opportunity for compact, high-efficiency concentrating photovoltaics to be installed on rooftops and other limited-space urban environments. PMID:25651754

  8. Commercial Application of a Photovoltaic Concentrator system. Phase I. Final report, 1 June 1978-28 February 1979

    SciTech Connect

    Anderson, D.J.; Anderson, E.R.; Bardwell, K.M.

    1980-04-01

    This report documents the design and analysis of the BDM CAPVC (Commercial Application of a Photovoltaic Concentrator) system. The preliminary design, prototype test and evaluation, system analysis, and final design of a large-scale concentrating photovoltaic system are described. The application is on an attractive new office building which represents a large potential market. The photovoltaic concentrating array is a roof-mounted, single-axis linear parabolic trough, using single crystalline silicon photovoltaic cells. A total of 6720 square feet of aperture is focussed on 13,944 PV cells. The photovoltaic system operates in parallel with the local utility in an augmentary loadsharing operating mode. The array is actively cooled and the thermal energy utilized for building heat during winter months. (WHK)

  9. Towards high efficiency air-processed near-infrared responsive photovoltaics: bulk heterojunction solar cells based on PbS/CdS core-shell quantum dots and TiO2 nanorod arrays.

    PubMed

    Gonfa, Belete Atomsa; Kim, Mee Rahn; Delegan, Nazar; Tavares, Ana C; Izquierdo, Ricardo; Wu, Nianqiang; El Khakani, My Ali; Ma, Dongling

    2015-06-14

    Near infrared (NIR) PbS quantum dots (QDs) have attracted significant research interest in solar cell applications as they offer several advantages, such as tunable band gaps, capability of absorbing NIR photons, low cost solution processability and high potential for multiple exciton generation. Nonetheless, reports on solar cells based on NIR PbS/CdS core-shell QDs, which are in general more stable and better passivated than PbS QDs and thus more promising for solar cell applications, remain very rare. Herein we report high efficiency bulk heterojunction QD solar cells involving hydrothermally grown TiO2 nanorod arrays and PbS/CdS core-shell QDs processed in air (except for a device thermal annealing step) with a photoresponse extended to wavelengths >1200 nm and with a power conversion efficiency (PCE) as high as 4.43%. This efficiency was achieved by introducing a thin, sputter-deposited, uniform TiO2 seed layer to improve the interface between the TiO2 nanorod arrays and the front electrode, by optimizing TiO2 nanorod length and by conducting QD annealing treatment to enhance charge carrier transport. It was found that the effect of the seed layer became more obvious when the TiO2 nanorods were longer. Although photocurrent did not change much, both open circuit voltage and fill factor clearly changed with TiO2 nanorod length. This was mainly attributed to the variation of charge transport and recombination processes, as evidenced by series and shunt resistance studies. The optimal PCE was obtained at the nanorod length of ∼450 nm. Annealing is shown to further increase the PCE by ∼18%, because of the improvement of charge carrier transport in the devices as evidenced by considerably increased photocurrent. Our results clearly demonstrate the potential of the PbS/CdS core-shell QDs for the achievement of high PCE, solution processable and NIR responsive QD solar cells.

  10. Energy requirement for the production of silicon solar arrays

    NASA Technical Reports Server (NTRS)

    Lindmayer, J.; Wihl, M.; Scheinine, A.; Rosenfield, T.; Wrigley, C. Y.; Morrison, A.; Anderson, J.; Clifford, A.; Lafky, W.

    1977-01-01

    The results of a study to investigate the feasibility of manufacturing photovoltaic solar array modules by the use of energy obtained from similar or identical photovoltaic sources are presented. The primary objective of this investigation was the characterization of the energy requirements of current and developing technologies which comprise the photovoltaic field. For cross-checking the energies of prevailing technologies data were also used and the wide-range assessment of alternative technologies included different refinement methods, various ways of producing light sheets, semicrystalline cells, etc. Energy data are utilized to model the behavior of a future solar breeder plant under various operational conditions.

  11. Designer Nanocrystal Materials for Photovoltaics

    NASA Astrophysics Data System (ADS)

    Kagan, Cherie

    Advances in synthetic methods allow a wide range of semiconductor nanocrystals (NCs) to be tailored in size and shape and to be used as building blocks in the design of NC solids. However, the long, insulating ligands commonly employed in the synthesis of colloidal NCs inhibit strong interparticle coupling and charge transport once NCs are assembled into the solids state as NC arrays. We will describe the range of short, compact ligand chemistries we employ to exchange the long, insulating ligands used in synthesis and to increase interparticle coupling. These ligand exchange processes can have a dramatic influence on NC surface chemistry as well as NC organization in the solids, showing examples of short-range order. Synergistically, we use 1) thermal evaporation and diffusion and 2) wet-chemical methods to introduce extrinsic impurities and non-stoichiometry to passivate surface traps and dope NC solids. NC coupling and doping provide control over the density of states and the carrier type, concentration, mobility, and lifetime, which we characterize by a range of electronic and spectroscopic techniques. We will describe the importance of engineering device interfaces to design NC materials for solar photovoltaics.

  12. Arteriosclerosis: facts and fancy.

    PubMed

    Fishbein, Michael C; Fishbein, Gregory A

    2015-01-01

    Arterial vascular diseases comprise the leading cause of death in the industrialized world. Every physician learns about the pathology of these diseases in medical school. All pathologists evaluate arterial disease in surgical pathology and/or autopsy specimens. All clinicians encounter patients with clinical manifestations of these diseases. With such a common and clinically-important group of entities one would think there would be a general understanding of the "known" information that exists. That is, physicians and scientists should be able to separate what is fact and what is fancy. This review article is intended to generate thought in this regard.

  13. Insulation fact sheet

    SciTech Connect

    1997-08-01

    Electricity bills, oil bills, gas bills - all homeowners pay for one or more of these utilities, and wish they paid less. Often many of us do not really know how to control or reduce our utility bills. We resign ourselves to high bills because we think that is the price we have to pay for a comfortable home. We encourage our children to turn off the lights and appliances, but may not recognize the benefits of insulating the attic. This publication provides facts relative to home insulation. It discusses where to insulate, what products to use, the decision making process, installation options, and sources of additional information.

  14. Superconductivity fact vs. fancy

    SciTech Connect

    Fitzgerald, K.

    1988-05-01

    The author says great advances have been made in superconductivity. However, the rush to secure recognition combined with public confusion over superconductivity has tainted the field with misconceptions. Some people are saying little progress towards practical use of the ceramics has been made over the last year and many researchers have left what they were doing to study superconductivity. All the hype surrounding the new found ceramic superconductors could give way to a period of disillusionment and frustration. This article discusses recent work in the field of superconductivity. IEEE Spectrum has adopted an attitude of ''just the facts'' in reporting superconductivity news.

  15. Analysis of the economics of photovoltaic-diesel-battery energy systems for remote applications

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.

    1983-01-01

    Computer simulations were conducted to analyze the performance and operating cost of a photovoltaic energy source combined with a diesel generator system and battery storage. The simulations were based on the load demand profiles used for the design of an all photovoltaic energy system installed in the remote Papago Indian Village of Schuchuli, Arizona. Twenty year simulations were run using solar insolation data from Phoenix SOLMET tapes. Total energy produced, energy consumed, operation and maintenance costs were calculated. The life cycle and levelized energy costs were determined for a variety of system configurations (i.e., varying amounts of photovoltaic array and battery storage).

  16. A novel photovoltaic power system which uses a large area concentrator mirror

    NASA Technical Reports Server (NTRS)

    Arrison, Anne; Fatemi, Navid

    1987-01-01

    A preliminary analysis has been made of a novel photovoltaic power system concept. The system is composed of a small area, dense photovoltaic array, a large area solar concentrator, and a battery system for energy storage. The feasibility of such a system is assessed for space power applications. The orbital efficiency, specific power, mass, and area of the system are calculated under various conditions and compared with those for the organic Rankine cycle solar dynamic system proposed for Space Station. Near term and advanced large area concentrator photovoltaic systems not only compare favorably to solar dynamic systems in terms of performance but offer other benefits as well.

  17. Flat-plate solar array project. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Callaghan, W.; Mcdonald, R.

    1986-01-01

    In 1975, the U.S. Government contracted the Jet Propulsion Lab. to develop, by 1985, in conjunction with industry, the photovoltaics (PV) module and array technology required for widespread use of photovoltaics as a significant terrestrial energy source. As a result, a project that eventually became known as the Flat Plate Solar Array (FSA) Project was formed to manage an industry, university, and Government team to perform the necessary research and development. The original goals were to achieve widespread commercial use of PV modules and arrays through the development of technology that would allow them to be profitably sold for $1.07/peak watts (1985 dollars). A 10% module conversion efficiency and a 20 year lifetime were also goals. It is intended that the executive summary provide the means by which one can gain a perspective on 11 years of terrestrial photovoltaic research and development conducted by the FSA Project.

  18. Design and construction experience from photovoltaic installations

    NASA Astrophysics Data System (ADS)

    Kauffman, W. R.; Lambarski, T. J.; Forrester, D. L.

    Lessons learned by one company during the design, construction, and operation of several prototype commercial photovoltaic (PV) power plants are reported. Intensive on-site quality control management was found necessary for controlling costs during installation of a 1 MW array for utility power production. A need to use modular components to offset high labor costs was noted. Installation of a 240 kW array of parabolic trough concentrators at a community school revealed the significance of stable support structures for tracking systems, which require reliable electronics for operation. A roof-mounted 50 kW array showed the potential hazards from wind damage and the greater economic benefits that accrue from maximizing output rather than cutting corners on the system costs. An airbase 40 kW array disclosed heat dissipation and moisture intrusion problems in ancillary equipment, and a residential 4.68 kW roof-mounted system demonstrated the increases in installation efficiency available with larger crews and greater experience.

  19. Flexible polycrystalline thin-film photovoltaics for space applications

    NASA Technical Reports Server (NTRS)

    Armstrong, J. H.; Lanning, B. R.; Misra, M. S.; Kapur, V. K.; Basol, B. M.

    1993-01-01

    Polycrystalline thin-film photovoltaics (PV), such as CIS and CdTe, have received considerable attention recently with respect to space power applications. Their combination of stability, efficiency, and economy from large-scale monolithic-integration of modules can have significant impact on cost and weight of PV arrays for spacecraft and planetary experiments. An added advantage, due to their minimal thickness (approximately 6 microns sans substrate), is the ability to manufacture lightweight, flexible devices (approximately 2000 W/kg) using large-volume manufacturing techniques. The photovoltaic effort at Martin Marietta and ISET is discussed, including large-area, large-volume thin-film deposition techniques such as electrodeposition and rotating cylindrical magnetron sputtering. Progress in the development of flexible polycrystalline thin-film PV is presented, including evaluation of flexible CIS cells. In addition, progress on flexible CdTe cells is presented. Finally, examples of lightweight, flexible arrays and their potential cost and weight impact is discussed.

  20. Inorganic Photovoltaics Materials and Devices: Past, Present, and Future

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Bailey, Sheila G.; Rafaelle, Ryne P.

    2005-01-01

    This report describes recent aspects of advanced inorganic materials for photovoltaics or solar cell applications. Specific materials examined will be high-efficiency silicon, gallium arsenide and related materials, and thin-film materials, particularly amorphous silicon and (polycrystalline) copper indium selenide. Some of the advanced concepts discussed include multi-junction III-V (and thin-film) devices, utilization of nanotechnology, specifically quantum dots, low-temperature chemical processing, polymer substrates for lightweight and low-cost solar arrays, concentrator cells, and integrated power devices. While many of these technologies will eventually be used for utility and consumer applications, their genesis can be traced back to challenging problems related to power generation for aerospace and defense. Because this overview of inorganic materials is included in a monogram focused on organic photovoltaics, fundamental issues and metrics common to all solar cell devices (and arrays) will be addressed.

  1. Photovoltaic restoration of sight with high visual acuity.

    PubMed

    Lorach, Henri; Goetz, Georges; Smith, Richard; Lei, Xin; Mandel, Yossi; Kamins, Theodore; Mathieson, Keith; Huie, Philip; Harris, James; Sher, Alexander; Palanker, Daniel

    2015-05-01

    Patients with retinal degeneration lose sight due to the gradual demise of photoreceptors. Electrical stimulation of surviving retinal neurons provides an alternative route for the delivery of visual information. We demonstrate that subretinal implants with 70-μm-wide photovoltaic pixels provide highly localized stimulation of retinal neurons in rats. The electrical receptive fields recorded in retinal ganglion cells were similar in size to the natural visual receptive fields. Similarly to normal vision, the retinal response to prosthetic stimulation exhibited flicker fusion at high frequencies, adaptation to static images and nonlinear spatial summation. In rats with retinal degeneration, these photovoltaic arrays elicited retinal responses with a spatial resolution of 64 ± 11 μm, corresponding to half of the normal visual acuity in healthy rats. The ease of implantation of these wireless and modular arrays, combined with their high resolution, opens the door to the functional restoration of sight in patients blinded by retinal degeneration.

  2. Flexible polycrystalline thin-film photovoltaics for space applications

    NASA Astrophysics Data System (ADS)

    Armstrong, J. H.; Lanning, B. R.; Misra, M. S.; Kapur, V. K.; Basol, B. M.

    1993-05-01

    Polycrystalline thin-film photovoltaics (PV), such as CIS and CdTe, have received considerable attention recently with respect to space power applications. Their combination of stability, efficiency, and economy from large-scale monolithic-integration of modules can have significant impact on cost and weight of PV arrays for spacecraft and planetary experiments. An added advantage, due to their minimal thickness (approximately 6 microns sans substrate), is the ability to manufacture lightweight, flexible devices (approximately 2000 W/kg) using large-volume manufacturing techniques. The photovoltaic effort at Martin Marietta and ISET is discussed, including large-area, large-volume thin-film deposition techniques such as electrodeposition and rotating cylindrical magnetron sputtering. Progress in the development of flexible polycrystalline thin-film PV is presented, including evaluation of flexible CIS cells. In addition, progress on flexible CdTe cells is presented. Finally, examples of lightweight, flexible arrays and their potential cost and weight impact is discussed.

  3. Low earth orbit environmental effects on the Space Station photovoltaic power generation systems

    NASA Technical Reports Server (NTRS)

    Nahra, H. K.

    1988-01-01

    A summary of the low earth orbital environment, its impact on the photovoltaic power systems of the Space Station and the solutions implemented to resolve the environmental concerns or issues are described. Low earth orbital environment (LEO) presents several concerns to the photovoltaic power systems of the Space Station. These concerns include atomic oxygen interaction with the polymeric substrate of the solar arrays, ionized environment effects on the array operating voltage, the effects of the meteoroids and debris impacts and penetration through the different layers of the solar cells and their circuits, and the high energy particle and radiation effects on the overall solar array performance. Potential solutions to some of the degrading environmental interactions that will provide the photovoltaic power system of the Space Station with the desired life are also summarized.

  4. Photovoltaic Specialists Conference, 15th, Kissimmee, FL, May 12-15, 1981, Conference Record

    NASA Astrophysics Data System (ADS)

    GaAs cells for space applications are considered, taking into account AlGaAs/GaAs high efficiency cascade solar cells, and a thermochemical model of radiation damage and continuous annealing applied to GaAs solar cells. Other topics discussed are related to silicon solar cells for space applications, photovoltaic concentrator receivers and application experiments, photovoltaic concentrator cells, economics and feasibility analysis, space solar cell calibration, low cost technology for space applications, thin film solar cells, low cost processes, and low cost cell and array processes. A description is also presented of subjects in the areas of low cost Si and sheet technology, amorphous silicon solar cells, flat-plate array subsystem and system technology, cadmium sulfide and copper sulfide solar cells, flat-plate array subsystem design and test methods, module failure/degradation mechanism and reliability, measurement techniques for photovoltaic cells and materials, and flat-plate residential and intermediate system applications.

  5. Low Earth orbit environmental effects on the space station photovoltaic power generation systems

    NASA Technical Reports Server (NTRS)

    Nahra, Henry K.

    1987-01-01

    A summary of the Low Earth Orbital Environment, its impact on the Photovoltaic Power systems of the space station and the solutions implemented to resolve the environmental concerns or issues are described. Low Earth Orbital Environment (LEO) presents several concerns to the Photovoltaic power systems of the space station. These concerns include atomic oxygen interaction with the polymeric substrate of the solar arrays, ionized environment effects on the array operating voltage, the effects of the meteoroids and debris impacts and penetration through the different layers of the solar cells and their circuits, and the high energy particle and radiation effects on the overall solar array performance. Potential solutions to some of the degrading environmental interactions that will provide the photovoltaic power system of the space station with the desired life are also summarized.

  6. Photovoltaic Pixels for Neural Stimulation: Circuit Models and Performance.

    PubMed

    Boinagrov, David; Lei, Xin; Goetz, Georges; Kamins, Theodore I; Mathieson, Keith; Galambos, Ludwig; Harris, James S; Palanker, Daniel

    2016-02-01

    Photovoltaic conversion of pulsed light into pulsed electric current enables optically-activated neural stimulation with miniature wireless implants. In photovoltaic retinal prostheses, patterns of near-infrared light projected from video goggles onto subretinal arrays of photovoltaic pixels are converted into patterns of current to stimulate the inner retinal neurons. We describe a model of these devices and evaluate the performance of photovoltaic circuits, including the electrode-electrolyte interface. Characteristics of the electrodes measured in saline with various voltages, pulse durations, and polarities were modeled as voltage-dependent capacitances and Faradaic resistances. The resulting mathematical model of the circuit yielded dynamics of the electric current generated by the photovoltaic pixels illuminated by pulsed light. Voltages measured in saline with a pipette electrode above the pixel closely matched results of the model. Using the circuit model, our pixel design was optimized for maximum charge injection under various lighting conditions and for different stimulation thresholds. To speed discharge of the electrodes between the pulses of light, a shunt resistor was introduced and optimized for high frequency stimulation.

  7. Sentinel-3 Solar Array Design

    NASA Astrophysics Data System (ADS)

    Combet, Y.; Reutenauer, X.; Mouret, G.; Guerrere, S.; Ergan, A.; Ferrando, E.; Riva, S.; Hodgetts, P.; Levesque, D.; D'Accolti, G.

    2011-10-01

    Sentinel-3 is primarily a mission to support services relating to the marine environment, with capability to serve numerous land-, atmospheric- and cryospheric- based application areas. The mission's main objective is to determine parameters, such as sea-surface topography, sea- and land-surface temperatures, as well as ocean- and land-surface colours with high-end accuracy and reliability. For this mission, Thales Alenia Space has been selected as the spacecraft prime contractor and is also responsible for the solar array. In this frame, TAS leads a European industrial team, comprising Selex Galileo for the photovoltaic assembly and Patria for the panel substrate.

  8. Photovoltaic module and interlocked stack of photovoltaic modules

    DOEpatents

    Wares, Brian S.

    2012-09-04

    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame having at least a top member and a bottom member. A plurality of alignment features are included on the top member of each frame, and a plurality of alignment features are included on the bottom member of each frame. Adjacent photovoltaic modules are interlocked by the alignment features on the top member of a lower module fitting together with the alignment features on the bottom member of an upper module. Other embodiments, features and aspects are also disclosed.

  9. Characterization of intermediate-sized photovoltaic system designs

    SciTech Connect

    Noel, G.T.; Ayres, J.G.

    1987-01-01

    Detailed descriptions of the designs and current hardware of nine intermediate- to large-sized DOE-funded photovoltaic projects are presented. For each site, a narrative description is accompanied by a photograph of the array field and a line diagram illustrating key design features and hardware. The systems described are Beverly High School, Dallas-Ft. Worth Airport, Georgetown University, Lovington Shopping Center, Natural Bridges National Monument, Newman Power Station, Oklahoma City Omniplex, Phoenix Sky Harbor Airport, and WBNO Radio Station.

  10. Evaluation of high-concentration photovoltaic power plants

    SciTech Connect

    Stolte, W.J. ); Whisnant, R.A. ); McGowin, C.R. )

    1991-01-01

    This paper describes the conceptual design, and estimated cost and performance of two high-concentration, 50 MW photovoltaic power plants. Both designs are based on a similar advanced back-contact silicon concentrator cell. The first design uses Fresnel lens/glass silo modules mounted on two-axis tracking arrays. The second design has all of the cells mounted on a central receiver on top of a single tower, with heliostats concentrating sunlight onto the receiver.

  11. Photovoltaic subsystem optimization and design tradeoff study. Final report

    SciTech Connect

    Stolte, W.J.

    1982-03-01

    Tradeoffs and subsystem choices are examined in photovoltaic array subfield design, power-conditioning sizing and selection, roof- and ground-mounted structure installation, energy loss, operating voltage, power conditioning cost, and subfield size. Line- and self-commutated power conditioning options are analyzed to determine the most cost-effective technology in the megawatt power range. Methods for reducing field installation of flat panels and roof mounting of intermediate load centers are discussed, including the cost of retrofit installations.

  12. Energy Systems Integration: NREL + SolarCity and the Hawaiian Electric Companies (Fact Sheet)

    SciTech Connect

    Not Available

    2015-02-01

    This fact sheet describes the collaboration between NREL, SolarCity, and the Hawaiian Electric Companies at the Energy Systems Integration Facility (ESIF) to address the safety, reliability, and stability challenges of interconnecting high penetrations of distributed photovoltaics with the electric power system.

  13. Photovoltaic prospects in Europe

    NASA Astrophysics Data System (ADS)

    Starr, M. R.

    The economics of solar cells is reviewed with an eye to potential cost reductions in processing, and potential markets are explored. Current solar cell systems costs are noted to be on the road to achieving the U.S. DoE goals of $0.40/kWp by 1990. Continued progress will depend on technical developments in cheaper materials and processes, scaling up production, and the success of sales programs. Various consumer and professional markets are outlined, with a prediction that a 12 MWp deman will be reached as a steady state by 1995. Photovoltaic panels may conceivably replace conventional roofing materials, resulting in the projection that, if grid-supplied power continues to inflate in price, then all new European homes would be equipped with photovoltaics by the year 2000. Further, accomplishment of the cost goals could generate a 1 GWp/yr industrial market at the same time.

  14. Superstructure high efficiency photovoltaics

    NASA Technical Reports Server (NTRS)

    Wagner, M.; So, L. C.; Leburton, J. P.

    1987-01-01

    A novel class of photovoltaic cascade structures is introduced which features multijunction upper subcells. These superstructure high efficiency photovoltaics (SHEP's) exhibit enhanced upper subcell spectral response because of the additional junctions which serve to reduce bulk recombination losses by decreasing the mean collection distance for photogenerated minority carriers. Two possible electrical configurations were studied and compared: a three-terminal scheme that allows both subcells to be operated at their individual maximum power points and a two-terminal configuration with an intercell ohmic contact for series interconnection. The three-terminal devices were found to be superior both in terms of beginning-of-life expectancy and radiation tolerance. Realistic simulations of three-terminal AlGaAs/GaAs SHEP's show that one sun AMO efficiencies in excess of 26 percent are possible.

  15. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated.

  16. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated. PMID:27087582

  17. Photovoltaic retinal prosthesis: implant fabrication and performance

    NASA Astrophysics Data System (ADS)

    Wang, Lele; Mathieson, K.; Kamins, T. I.; Loudin, J. D.; Galambos, L.; Goetz, G.; Sher, A.; Mandel, Y.; Huie, P.; Lavinsky, D.; Harris, J. S.; Palanker, D. V.

    2012-08-01

    The objective of this work is to develop and test a photovoltaic retinal prosthesis for restoring sight to patients blinded by degenerative retinal diseases. A silicon photodiode array for subretinal stimulation has been fabricated by a silicon-integrated-circuit/MEMS process. Each pixel in the two-dimensional array contains three series-connected photodiodes, which photovoltaically convert pulsed near-infrared light into bi-phasic current to stimulate nearby retinal neurons without wired power connections. The device thickness is chosen to be 30 µm to absorb a significant portion of light while still being thin enough for subretinal implantation. Active and return electrodes confine current near each pixel and are sputter coated with iridium oxide to enhance charge injection levels and provide a stable neural interface. Pixels are separated by 5 µm wide trenches to electrically isolate them and to allow nutrient diffusion through the device. Three sizes of pixels (280, 140 and 70 µm) with active electrodes of 80, 40 and 20 µm diameter were fabricated. The turn-on voltages of the one-diode, two-series-connected diode and three-series-connected diode structures are approximately 0.6, 1.2 and 1.8 V, respectively. The measured photo-responsivity per diode at 880 nm wavelength is ˜0.36 A W-1, at zero voltage bias and scales with the exposed silicon area. For all three pixel sizes, the reverse-bias dark current is sufficiently low (<100 pA) for our application. Pixels of all three sizes reliably elicit retinal responses at safe near-infrared light irradiances, with good acceptance of the photodiode array in the subretinal space. The fabricated device delivers efficient retinal stimulation at safe near-infrared light irradiances without any wired power connections, which greatly simplifies the implantation procedure. Presence of the return electrodes in each pixel helps to localize the current, and thereby improves resolution.

  18. Photovoltaic retinal prosthesis: implant fabrication and performance.

    PubMed

    Wang, Lele; Mathieson, K; Kamins, T I; Loudin, J D; Galambos, L; Goetz, G; Sher, A; Mandel, Y; Huie, P; Lavinsky, D; Harris, J S; Palanker, D V

    2012-08-01

    The objective of this work is to develop and test a photovoltaic retinal prosthesis for restoring sight to patients blinded by degenerative retinal diseases. A silicon photodiode array for subretinal stimulation has been fabricated by a silicon-integrated-circuit/MEMS process. Each pixel in the two-dimensional array contains three series-connected photodiodes, which photovoltaically convert pulsed near-infrared light into bi-phasic current to stimulate nearby retinal neurons without wired power connections. The device thickness is chosen to be 30 µm to absorb a significant portion of light while still being thin enough for subretinal implantation. Active and return electrodes confine current near each pixel and are sputter coated with iridium oxide to enhance charge injection levels and provide a stable neural interface. Pixels are separated by 5 µm wide trenches to electrically isolate them and to allow nutrient diffusion through the device. Three sizes of pixels (280, 140 and 70 µm) with active electrodes of 80, 40 and 20 µm diameter were fabricated. The turn-on voltages of the one-diode, two-series-connected diode and three-series-connected diode structures are approximately 0.6, 1.2 and 1.8 V, respectively. The measured photo-responsivity per diode at 880 nm wavelength is ∼0.36 A W(-1), at zero voltage bias and scales with the exposed silicon area. For all three pixel sizes, the reverse-bias dark current is sufficiently low (<100 pA) for our application. Pixels of all three sizes reliably elicit retinal responses at safe near-infrared light irradiances, with good acceptance of the photodiode array in the subretinal space. The fabricated device delivers efficient retinal stimulation at safe near-infrared light irradiances without any wired power connections, which greatly simplifies the implantation procedure. Presence of the return electrodes in each pixel helps to localize the current, and thereby improves resolution.

  19. Overview of Photovoltaic Calibration and Measurement Standards at GRC

    NASA Technical Reports Server (NTRS)

    Baraona, Cosmo; Snyder, David; Brinker, David; Bailey, Sheila; Curtis, Henry; Scheiman, David; Jenkins, Phillip

    2002-01-01

    Photovoltaic (PV) systems (cells and arrays) for spacecraft power have become an international market. This market demands accurate prediction of the solar array power output in space throughout the mission life of the spacecraft. Since the beginning of space flight, space-faring nations have independently developed methods to calibrate solar cells for power output in low Earth orbit (LEO). These methods rely on terrestrial, laboratory, or extraterrestrial light sources to simulate or approximate the air mass zero (AM0) solar intensity and spectrum.

  20. Increased voltage photovoltaic cell

    NASA Technical Reports Server (NTRS)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.