Field Performance of Photovoltaic Systems in the Tucson Desert

NASA Astrophysics Data System (ADS)

Orsburn, Sean; Brooks, Adria; Cormode, Daniel; Greenberg, James; Hardesty, Garrett; Lonij, Vincent; Salhab, Anas; St. Germaine, Tyler; Torres, Gabe; Cronin, Alexander

2011-10-01

At the Tucson Electric Power (TEP) solar test yard, over 20 different grid-connected photovoltaic (PV) systems are being tested. The goal at the TEP solar test yard is to measure and model real-world performance of PV systems and to benchmark new technologies such as holographic concentrators. By studying voltage and current produced by the PV systems as a function of incident irradiance, and module temperature, we can compare our measurements of field-performance (in a harsh desert environment) to manufacturer specifications (determined under laboratory conditions). In order to measure high-voltage and high-current signals, we designed and built reliable, accurate sensors that can handle extreme desert temperatures. We will present several benchmarks of sensors in a controlled environment, including shunt resistors and Hall-effect current sensors, to determine temperature drift and accuracy. Finally we will present preliminary field measurements of PV performance for several different PV technologies.

Near-field transport imaging applied to photovoltaic materials

DOE PAGES

Xiao, Chuanxiao; Jiang, Chun -Sheng; Moseley, John; ...

2017-05-26

We developed and applied a new analytical technique - near-field transport imaging (NF-TI or simply TI) - to photovoltaic materials. Charge-carrier transport is an important factor in solar cell performance, and TI is an innovative approach that integrates a scanning electron microscope with a near-field scanning optical microscope, providing the possibility to study luminescence associated with recombination and transport with high spatial resolution. In this paper, we describe in detail the technical barriers we had to overcome to develop the technique for routine application and the data-fitting procedure used to calculate minority-carrier diffusion length values. The diffusion length measured bymore » TI agrees well with the results calculated by time-resolved photoluminescence on well-controlled gallium arsenide (GaAs) thin-film samples. We report for the first time on measurements on thin-film cadmium telluride using this technique, including the determination of effective carrier diffusion length, as well as the first near-field imaging of the effect of a single localized defect on carrier transport and recombination in a GaAs heterostructure. Furthermore, by changing the scanning setup, we were able to demonstrate near-field cathodoluminescence (CL), and correlated the results with standard CL measurements. In conclusion, the TI technique shows great potential for mapping transport properties in solar cell materials with high spatial resolution.« less

Photovoltaic research and development in Japan

NASA Technical Reports Server (NTRS)

Shimada, K.

1983-01-01

The status of the Japanese photovoltaic (PV) R&D activities was surveyed through literature searches, private communications, and site visits in 1982. The results show that the Japanese photovoltaic technology is maturing rapidly, consistent with the steady government funding under the Sunshine Project. Two main thrusts of the Project are: (1) completion of the solar panel production pilot plants using cast ingot and sheet silicon materials, and (2) development of large area amorphous silicon solar cells with acceptable efficiency (10 to 12%). An experimental automated solar panel production plant rated at 500 kW/yr is currently under construction for the Sunshine Project for completion in March 1983. Efficiencies demonstrated by experimental large are amorphous silicon solar cells are approaching 8%. Small area amorphous silicon solar cells are, however, currently being mass produced and marketed by several companies at an equivalent annual rate of 2 MW/yr for consumer electronic applications. There is no evidence of an immediate move by the Japanese PV industry to enter extensively into the photovoltaic power market, domestic or otherwise. However, the photovoltaic technology itself could become ready for such an entry in the very near future, especially by making use of advanced process automation technologies.

Magnetic field-driven lateral photovoltaic effect in the Fe/SiO2/p-Si hybrid structure with the Schottky barrier

NASA Astrophysics Data System (ADS)

Volkov, N. V.; Rautskii, M. V.; Tarasov, A. S.; Yakovlev, I. A.; Bondarev, I. A.; Lukyanenko, A. V.; Varnakov, S. N.; Ovchinnikov, S. G.

2018-07-01

We demonstrate that the lateral photovoltaic effect in the Fe/SiO2/p-Si structure not only strongly depends on the optical radiation wavelength and temperature, but is also sensitive to external magnetic fields. The magnetic field lowers the absolute value of photovoltage regardless of the wavelength and temperature; however, the relative photovoltage variation significantly depends on these parameters. The lateral photovoltage is observed both on the Fe film and Si substrate sides and results from separation of photoinduced electrons and holes in a built-in electric field of the Schottky barrier with their subsequent diffusion to the structure in the lateral direction from the illuminated area. The observed features in the behavior of the lateral photovoltaic effect originate from the variation in the light absorption coefficient of the semiconductor and the related quantum efficiency upon light wavelength variation. In addition, an important role is played by the change in the characteristics of the Schottky barrier at the redistribution of optically generated carriers and temperature variation. The effect of the magnetic field is attributed to the Lorentz force, which bends trajectories of carriers drifting under the action of the Schottky barrier field and, consequently, suppresses the lateral photovoltaic effect.

Tuning the photovoltaic effect of multiferroic CoFe2O4/Pb(Zr, Ti)O3 composite films by magnetic fields

NASA Astrophysics Data System (ADS)

Pan, Dan-Feng; Chen, Guang-Yi; Bi, Gui-Feng; Zhang, Hao; Liu, Jun-Ming; Wang, Guang-Hou; Wan, Jian-Guo

2016-05-01

The 0-3 type CoFe2O4-Pb(Zr,Ti)O3 (CFO-PZT) multiferroic composite films have been prepared by a sol-gel process and spin-coating technique. A confirmable photovoltaic effect is observed under ultraviolet light irradiation. Moreover, this photovoltaic effect can be tuned by external magnetic fields. The maximum magnetic modulation ratios of short-circuit current density and open-circuit voltage can reach as high as 13.7% and 12.8% upon the application of 6 kOe DC magnetic field. Through remnant polarization measurements under various magnetic fields and detailed analysis of the energy band structures, we elucidate the mechanism of tuning photovoltaic effect by magnetic fields and attribute it to the combination of two factors. One is the decreased ferroelectric-polarization-induced depolarization electric field and another is the band structure reconstruction at CFO-PZT interfaces, both of which are dominated by the magnetoelectric coupling via interfacial stress transferring at nanoscale. This work makes some attempts of coupling photo-induced effects with magnetoelectric effect in multiferroic materials and will widen the practical ranges of multiferroic-based applications.

Graphene-based photovoltaic cells for near-field thermal energy conversion

PubMed Central

Messina, Riccardo; Ben-Abdallah, Philippe

2013-01-01

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat. PMID:23474891

Graphene-based photovoltaic cells for near-field thermal energy conversion.

PubMed

Messina, Riccardo; Ben-Abdallah, Philippe

2013-01-01

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. While their efficiency is limited in far field by the Schockley-Queisser limit, in near field the heat flux transferred to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular for a source supporting a surface mode. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. In this paper we propose a modified thermophotovoltaic device in which the cell is covered by a graphene sheet. By discussing the transmission coefficient and the spectral properties of the flux, we show that both the cell efficiency and the produced current can be enhanced, paving the way to promising developments for the production of electricity from waste heat.

Low-cost modular array-field designs for flat-panel and concentrator photovoltaic systems

NASA Astrophysics Data System (ADS)

Post, H. N.; Carmichael, D. C.; Alexander, G.; Castle, J. A.

1982-09-01

Described are the design and development of low-cost, modular array fields for flat-panel and concentrator photovoltaic (PV) systems. The objective of the work was to reduce substantially the cost of the array-field Balance-of-System (BOS) subsystems and site-specific design costs as compared to previous PV installations. These subsystems include site preparation, foundations, support structures, electrical writing, grounding, lightning protection, electromagnetic interference considerations, and controls. To reduce these BOS and design costs, standardized modular (building-block) designs for flat-panel and concentrator array fields have been developed that are fully integrated and optimized for lowest life-cycle costs. Using drawings and specifications now available, these building-block designs can be used in multiples to install various size array fields. The developed designs are immediately applicable (1982) and reduce the array-field BOS costs to a fraction of previous costs.

Electromagnetic Fields Associated with Commercial Solar Photovoltaic Electric Power Generating Facilities.

PubMed

Tell, R A; Hooper, H C; Sias, G G; Mezei, G; Hung, P; Kavet, R

2015-01-01

The southwest region of the United States is expected to experience an expansion of commercial solar photovoltaic generation facilities over the next 25 years. A solar facility converts direct current generated by the solar panels to three-phase 60-Hz power that is fed to the grid. This conversion involves sequential processing of the direct current through an inverter that produces low-voltage three-phase power, which is stepped up to distribution voltage (∼12 kV) through a transformer. This study characterized magnetic and electric fields between the frequencies of 0 Hz and 3 GHz at two facilities operated by the Southern California Edison Company in Porterville, CA and San Bernardino, CA. Static magnetic fields were very small compared to exposure limits established by IEEE and ICNIRP. The highest 60-Hz magnetic fields were measured adjacent to transformers and inverters, and radiofrequency fields from 5-100 kHz were associated with the inverters. The fields measured complied in every case with IEEE controlled and ICNIRP occupational exposure limits. In all cases, electric fields were negligible compared to IEEE and ICNIRP limits across the spectrum measured and when compared to the FCC limits (≥0.3 MHz).

Photovoltaic system criteria documents. Volume 1: Guidelines for evaluating the management and operations planning of photovoltaic applications

NASA Technical Reports Server (NTRS)

Koenig, John C.; Billitti, Joseph W.; Tallon, John M.

1979-01-01

Guidelines are provided to the Field Centers for organization, scheduling, project and cost control, and performance in the areas of project management and operations planning for Photovoltaics Test and Applications. These guidelines may be used in organizing a T and A Project Team for system design/test, site construction and operation, and as the basis for evaluating T and A proposals. The attributes are described for project management and operations planning to be used by the Field Centers. Specifically, all project management and operational issues affecting costs, schedules and performance of photovoltaic systems are addressed. Photovoltaic tests and applications include residential, intermediate load center, central station, and stand-alone systems. The sub-categories of system maturity considered are: Initial System Evaluation Experiments (ISEE); System Readiness Experiments (SRE); and Commercial Readiness Demonstration Projects (CRDP).

Design and validation of a foldable and photovoltaic wide-field epiretinal prosthesis.

PubMed

Ferlauto, Laura; Airaghi Leccardi, Marta Jole Ildelfonsa; Chenais, Naïg Aurelia Ludmilla; Gilliéron, Samuel Charles Antoine; Vagni, Paola; Bevilacqua, Michele; Wolfensberger, Thomas J; Sivula, Kevin; Ghezzi, Diego

2018-03-08

Retinal prostheses have been developed to fight blindness in people affected by outer retinal layer dystrophies. To date, few hundred patients have received a retinal implant. Inspired by intraocular lenses, we have designed a foldable and photovoltaic wide-field epiretinal prosthesis (named POLYRETINA) capable of stimulating wireless retinal ganglion cells. Here we show that within a visual angle of 46.3 degrees, POLYRETINA embeds 2215 stimulating pixels, of which 967 are in the central area of 5 mm, it is foldable to allow implantation through a small scleral incision, and it has a hemispherical shape to match the curvature of the eye. We demonstrate that it is not cytotoxic and respects optical and thermal safety standards; accelerated ageing shows a lifetime of at least 2 years. POLYRETINA represents significant progress towards the improvement of both visual acuity and visual field with the same device, a current challenging issue in the field.

Design and fabrication of a photovoltaic power system for the Papago Indian village of Schuchuli (Gunsight), Arizona

NASA Technical Reports Server (NTRS)

Bifano, W. J.; Ratajczak, A. F.; Ice, W. J.

1978-01-01

A stand alone photovoltaic power system for installation in the Papago Indian village of Schuchuli is being designed and fabricated to provide electricity for village water pumping and basic domestic needs. The system will consist of a 3.5 kW (peak) photovoltaic array; controls, instrumentations, and storage batteries located in an electrical equipment building and a 120 volt dc village distribution network. The system will power a 2 HP dc electric motor.

Photovoltaic performance models: an evaluation with actual field data

NASA Astrophysics Data System (ADS)

TamizhMani, Govindasamy; Ishioye, John-Paul; Voropayev, Arseniy; Kang, Yi

2008-08-01

Prediction of energy production is crucial to the design and installation of the building integrated photovoltaic systems. This prediction should be attainable based on the commonly available parameters such as system size, orientation and tilt angle. Several commercially available as well as free downloadable software tools exist to predict energy production. Six software models have been evaluated in this study and they are: PV Watts, PVsyst, MAUI, Clean Power Estimator, Solar Advisor Model (SAM) and RETScreen. This evaluation has been done by comparing the monthly, seasonaly and annually predicted data with the actual, field data obtained over a year period on a large number of residential PV systems ranging between 2 and 3 kWdc. All the systems are located in Arizona, within the Phoenix metropolitan area which lies at latitude 33° North, and longitude 112 West, and are all connected to the electrical grid.

Magnetic fields from domestic appliances in the UK.

PubMed

Preece, A W; Kaune, W; Grainger, P; Preece, S; Golding, J

1997-01-01

In a survey of 50 UK homes the 50 Hz fundamental and harmonic magnetic fields generated by 806 domestic appliances found in the homes, and used regularly by mothers, were measured. Measurements were made in the direction of most likely access, and from the surface of the appliances. Mothers completed a questionnaire on the use of appliances and were monitored for 24 h so that acquired exposure could be compared with the measured ambient fields in the home. Appliances were measured at standard distances and an algorithm was used to calculate fields at 100 and 50 cm to remove room background contributions. A few appliances generated fields in excess of 0.2 microT at 1 m: microwave cookers 0.37 +/- 0.14 microT; washing machines 0.27 +/- 0.14 microT; dishwashers 0.23 +/- 0.13 microT; some electric showers 0.11 +/- 0.25 microT and can openers 0.20 +/- 0.21 microT. Of continuously operating devices, only central heating pumps (0.51 +/- 0.47 microT), central heating boilers (0.27 +/- 0.26 microT) and fish-tank air pumps (0.32 +/- 0.09 microT) produced significant fields at 0.5 m. There were no obvious ways to group different types of appliances as high- or low-strength sources. Mothers spent on average about 4.5 h per day in the kitchen, where the strongest sources of magnetic field were located.

U.S. Department of Energy photovoltaic energy program contract summary, fiscal year 1999

DOE Office of Scientific and Technical Information (OSTI.GOV)

Surek, T.; Hansen, A.

2000-02-17

This report summarizes the in-house and subcontracted research and development (R and D) activities under the National Center for Photovoltaics (NCPV) and US Department of Energy (DOE) National Photovoltaics Program from October 1, 1998, through September 30, 1999 (FY 1999). The mission of the DOE National Photovoltaics Program is to make PV a significant part of the domestic economy as an industry and an energy resource. The two primary goals of the national program are to (1) maintain the US industry's world leadership in research and technology development and (2) help the US industry remain a major, profitable force inmore » the world market. The NCPV is part of the National PV Program and provides leadership and support to the national program toward achieving its mission and goals.« less

Photovoltaic Reliability Workshop Lodging Information | Photovoltaic

Science.gov Websites

Research | NREL Photovoltaic Reliability Workshop Lodging Information Photovoltaic Reliability Workshop Lodging Information The 2018 Photovoltaic Reliability Workshop (PVRW) will be held Tuesday

From Crop Domestication to Super-domestication

PubMed Central

Vaughan, D. A.; Balázs, E.; Heslop-Harrison, J. S.

2007-01-01

Research related to crop domestication has been transformed by technologies and discoveries in the genome sciences as well as information-related sciences that are providing new tools for bioinformatics and systems' biology. Rapid progress in archaeobotany and ethnobotany are also contributing new knowledge to understanding crop domestication. This sense of rapid progress is encapsulated in this Special Issue, which contains 18 papers by scientists in botanical, crop sciences and related disciplines on the topic of crop domestication. One paper focuses on current themes in the genetics of crop domestication across crops, whereas other papers have a crop or geographic focus. One feature of progress in the sciences related to crop domestication is the availability of well-characterized germplasm resources in the global network of genetic resources centres (genebanks). Germplasm in genebanks is providing research materials for understanding domestication as well as for plant breeding. In this review, we highlight current genetic themes related to crop domestication. Impressive progress in this field in recent years is transforming plant breeding into crop engineering to meet the human need for increased crop yield with the minimum environmental impact – we consider this to be ‘super-domestication’. While the time scale of domestication of 10 000 years or less is a very short evolutionary time span, the details emerging of what has happened and what is happening provide a window to see where domestication might – and can – advance in the future. PMID:17940074

Giant switchable photovoltaic effect in organometal trihalide perovskite devices

DOE PAGES

Xiao, Zhengguo; Yuan, Yongbo; Shao, Yuchuan; ...

2014-12-08

Organolead trihalide perovskite (OTP) materials are emerging as naturally abundant materials for low-cost, solution-processed and highly efficient solar cells. Here, we show that, in OTP-based photovoltaic devices with vertical and lateral cell configurations, the photocurrent direction can be switched repeatedly by applying a small electric field of <1 V μm –1. The switchable photocurrent, generally observed in devices based on ferroelectric materials, reached 20.1 mA cm –2 under one sun illumination in OTP devices with a vertical architecture, which is four orders of magnitude larger than that measured in other ferroelectric photovoltaic devices. This field-switchable photovoltaic effect can be explainedmore » by the formation of reversible p–i–n structures induced by ion drift in the perovskite layer. Furthermore, the demonstration of switchable OTP photovoltaics and electric-field-manipulated doping paves the way for innovative solar cell designs and for the exploitation of OTP materials in electrically and optically readable memristors and circuits.« less

Giant switchable photovoltaic effect in organometal trihalide perovskite devices

NASA Astrophysics Data System (ADS)

Xiao, Zhengguo; Yuan, Yongbo; Shao, Yuchuan; Wang, Qi; Dong, Qingfeng; Bi, Cheng; Sharma, Pankaj; Gruverman, Alexei; Huang, Jinsong

2015-02-01

Organolead trihalide perovskite (OTP) materials are emerging as naturally abundant materials for low-cost, solution-processed and highly efficient solar cells. Here, we show that, in OTP-based photovoltaic devices with vertical and lateral cell configurations, the photocurrent direction can be switched repeatedly by applying a small electric field of <1 V μm-1. The switchable photocurrent, generally observed in devices based on ferroelectric materials, reached 20.1 mA cm-2 under one sun illumination in OTP devices with a vertical architecture, which is four orders of magnitude larger than that measured in other ferroelectric photovoltaic devices. This field-switchable photovoltaic effect can be explained by the formation of reversible p-i-n structures induced by ion drift in the perovskite layer. The demonstration of switchable OTP photovoltaics and electric-field-manipulated doping paves the way for innovative solar cell designs and for the exploitation of OTP materials in electrically and optically readable memristors and circuits.

Some tests of flat plate photovoltaic module cell temperatures in simulated field conditions

NASA Technical Reports Server (NTRS)

Griffith, J. S.; Rathod, M. S.; Paslaski, J.

1981-01-01

The nominal operating cell temperature (NOCT) of solar photovoltaic (PV) modules is an important characteristic. Typically, the power output of a PV module decreases 0.5% per deg C rise in cell temperature. Several tests were run with artificial sun and wind to study the parametric dependencies of cell temperature on wind speed and direction and ambient temperature. It was found that the cell temperature is extremely sensitive to wind speed, moderately so to wind direction and rather insensitive to ambient temperature. Several suggestions are made to obtain data more typical of field conditions.

Photovoltaic power generation system with photovoltaic cells as bypass diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lentine, Anthony L.; Nielson, Gregory N.; Tauke-Pedretti, Anna

A photovoltaic power generation system that includes a solar panel is described herein. The solar panel includes a photovoltaic sub-module, which includes a group of microsystem enabled photovoltaic cells. The group includes a first string of photovoltaic cells, a second string of photovoltaic cells, and a differing photovoltaic cell. Photovoltaic cells in the first string are electrically connected in series, and photovoltaic cells in the second string are electrically connected in series. Further, the first string of photovoltaic cells, the second string of photovoltaic cells, and the differing photovoltaic cell are electrically connected in parallel. Moreover, the differing photovoltaic cellmore » is used as a bypass diode for the first string of photovoltaic cells and the second string of photovoltaic cells.« less

A molecular spin-photovoltaic device.

PubMed

Sun, Xiangnan; Vélez, Saül; Atxabal, Ainhoa; Bedoya-Pinto, Amilcar; Parui, Subir; Zhu, Xiangwei; Llopis, Roger; Casanova, Fèlix; Hueso, Luis E

2017-08-18

We fabricated a C 60 fullerene-based molecular spin-photovoltaic device that integrates a photovoltaic response with the spin transport across the molecular layer. The photovoltaic response can be modified under the application of a small magnetic field, with a magnetophotovoltage of up to 5% at room temperature. Device functionalities include a magnetic current inverter and the presence of diverging magnetocurrent at certain illumination levels that could be useful for sensing. Completely spin-polarized currents can be created by balancing the external partially spin-polarized injection with the photogenerated carriers. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Spatiotemporal characteristics of retinal response to network-mediated photovoltaic stimulation.

PubMed

Ho, Elton; Smith, Richard; Goetz, Georges; Lei, Xin; Galambos, Ludwig; Kamins, Theodore I; Harris, James; Mathieson, Keith; Palanker, Daniel; Sher, Alexander

2018-02-01

Subretinal prostheses aim at restoring sight to patients blinded by photoreceptor degeneration using electrical activation of the surviving inner retinal neurons. Today, such implants deliver visual information with low-frequency stimulation, resulting in discontinuous visual percepts. We measured retinal responses to complex visual stimuli delivered at video rate via a photovoltaic subretinal implant and by visible light. Using a multielectrode array to record from retinal ganglion cells (RGCs) in the healthy and degenerated rat retina ex vivo, we estimated their spatiotemporal properties from the spike-triggered average responses to photovoltaic binary white noise stimulus with 70-μm pixel size at 20-Hz frame rate. The average photovoltaic receptive field size was 194 ± 3 μm (mean ± SE), similar to that of visual responses (221 ± 4 μm), but response latency was significantly shorter with photovoltaic stimulation. Both visual and photovoltaic receptive fields had an opposing center-surround structure. In the healthy retina, ON RGCs had photovoltaic OFF responses, and vice versa. This reversal is consistent with depolarization of photoreceptors by electrical pulses, as opposed to their hyperpolarization under increasing light, although alternative mechanisms cannot be excluded. In degenerate retina, both ON and OFF photovoltaic responses were observed, but in the absence of visual responses, it is not clear what functional RGC types they correspond to. Degenerate retina maintained the antagonistic center-surround organization of receptive fields. These fast and spatially localized network-mediated ON and OFF responses to subretinal stimulation via photovoltaic pixels with local return electrodes raise confidence in the possibility of providing more functional prosthetic vision. NEW & NOTEWORTHY Retinal prostheses currently in clinical use have struggled to deliver visual information at naturalistic frequencies, resulting in discontinuous percepts. We

Organic Photovoltaic Solar Cells | Photovoltaic Research | NREL

Science.gov Websites

Organic Photovoltaic Solar Cells Organic Photovoltaic Solar Cells The National Center for Photovoltaics (NCPV) at NREL has strong complementary research capabilities in organic photovoltaic (OPV) cells pages: High-Efficiency Crystalline PV Polycrystalline Thin-Film PV Perovskite and Organic PV Advanced PV

Photovoltaic system criteria documents. Volume 2: Quality assurance criteria for photovoltaic applications

NASA Technical Reports Server (NTRS)

Koenig, John C.; Billitti, Joseph W.; Tallon, John M.

1979-01-01

Quality assurance criteria are described for manufacturers and installers of solar photovoltaic tests and applications. Quality oriented activities are outlined to be pursued by the contractor/subcontractor to assure the physical and operational quality of equipment produced is included. In the broad sense, guidelines are provided for establishing a QA organization if none exists. Mainly, criteria is provided to be considered in any PV quality assurance plan selected as appropriate by the responsible Field Center. A framework is established for a systematic approach to ensure that photovoltaic tests and applications are constructed in a timely and cost effective manner.

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.

Photovoltaic energy program overview, fiscal year 1991

NASA Astrophysics Data System (ADS)

1992-02-01

The Photovoltaics Program Plan, FY 1991 to FY 1995 builds on the accomplishments of the past 5 years and broadens the scope of program activities for the future. The previous plan emphasized materials and PV cell research. Under the balanced new plan, the PV Program continues its commitment to strategic research and development (R&D) into PV materials and processes, while also beginning work on PV systems and helping the PV industry encourage new markets for photovoltaics. A major challenge for the program is to assist the US PV industry in laying the foundation for at least 1000 MW of installed PV capacity in the United States and 500 MW internationally by 2000. As part of the new plan, the program expanded the scope of its activities in 1991. The PV Program is now addressing many new aspects of developing and commercializing photovoltaics. It is expanding activities with the US PV industry through the PV Manufacturing Technology (PVMaT) project, designed to address US manufacturers' immediate problems; providing technical assistance to potential end users such as electric utilities; and the program is turning its attention to encouraging new markets for PV. In 1991, for example, the PV Program initiated a new project with the PV industry to encourage a domestic market for PV applications in buildings and began cooperative ventures to support other countries such as Mexico to use PV in their rural electrification programs. This report reviews some of the development, fabrication and manufacturing advances in photovoltaics this year.

Photovoltaic roofing tile systems

NASA Astrophysics Data System (ADS)

Melchior, B.

The integration of photovoltaic (PV) systems in architecture is discussed. A PV-solar roofing tile system with polymer concrete base; PV-roofing tile with elastomer frame profiles and aluminum profile frames; contact technique; and solar cell modules measuring technique are described. Field tests at several places were conducted on the solar generator, electric current behavior, battery station, electric installation, power conditioner, solar measuring system with magnetic bubble memory technique, data transmission via telephone modems, and data processing system. The very favorable response to the PV-compact system proves the commercial possibilities of photovoltaic integration in architecture.

2015 NREL Photovoltaic Reliability Workshops | Photovoltaic Research | NREL

Science.gov Websites

5 NREL Photovoltaic Reliability Workshops 2015 NREL Photovoltaic Reliability Workshops The 2015 NREL Photovoltaic Reliability Workshop was held February 24-27, 2015, in Golden, Colorado. This event be available for download as soon as possible. The Photovoltaic Module Reliability Workshop is

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.

Market assessment of photovoltaic power systems for agricultural applications in Colombia

NASA Technical Reports Server (NTRS)

Steigelmann, W.; Neyeloff, S.

1981-01-01

The market potential for photovoltaic systems in the agricultural sector of Colombia is assessed. Consideration was given to over twenty specific livestock production, crop production, and rural services applications requiring less than 15 kW of power without backup power. Analysis revealed that near-term potential exists for photovoltaic technology in applications in coffee depulging, cattle watering, rural domestic users, rural water supply and small irrigation, rural telephones, rural health posts, and vaccine refrigeration. Market size would be in the 1200 to 2500 kWp range in the 1981 to 86 timeframe. Positive factors influencing the market size include a lack of electrical services, potential for developing the Llanos Orientales Territory, high fuel costs in remote areas, balance of system availability, the presence of wealthy land owners, and a large government-sponsored contract for photovoltaic (PV)-powered rural telephone systems. The anticipated eligibility of photovoltaic equipment for loans would be a further positive factor in market potential. Important negative factors include relatively inexpensive energy in developed locations, reliance on hydropower, lack of familiarity with PV equipment, a lack of financing, and established foreign competition in PV technology. Recommendations to American PV manufacturers attempting to develop the Colombian market are given.

Market assessment of photovoltaic power systems for agricultural applications in Colombia

NASA Astrophysics Data System (ADS)

Steigelmann, W.; Neyeloff, S.

1981-11-01

The market potential for photovoltaic systems in the agricultural sector of Colombia is assessed. Consideration was given to over twenty specific livestock production, crop production, and rural services applications requiring less than 15 kW of power without backup power. Analysis revealed that near-term potential exists for photovoltaic technology in applications in coffee depulging, cattle watering, rural domestic users, rural water supply and small irrigation, rural telephones, rural health posts, and vaccine refrigeration. Market size would be in the 1200 to 2500 kWp range in the 1981 to 86 timeframe. Positive factors influencing the market size include a lack of electrical services, potential for developing the Llanos Orientales Territory, high fuel costs in remote areas, balance of system availability, the presence of wealthy land owners, and a large government-sponsored contract for photovoltaic (PV)-powered rural telephone systems. The anticipated eligibility of photovoltaic equipment for loans would be a further positive factor in market potential. Important negative factors include relatively inexpensive energy in developed locations, reliance on hydropower, lack of familiarity with PV equipment, a lack of financing, and established foreign competition in PV technology. Recommendations to American PV manufacturers attempting to develop the Colombian market are given.

Modeling of four-terminal solar photovoltaic systems for field application

NASA Astrophysics Data System (ADS)

Vahanka, Harikrushna; Purohit, Zeel; Tripathi, Brijesh

2018-05-01

In this article a theoretical framework for mechanically stacked four-terminal solar photovoltaic (FTSPV) system has been proposed. In a mechanical stack arrangement, a semitransparent CdTe panel has been used as a top sub-module, whereas a μc-Si solar panel has been used as bottom sub-module. Theoretical modeling has been done to analyze the physical processes in the system and to estimate reliable prediction of the performance. To incorporate the effect of material, the band gap and the absorption coefficient data for CdTe and μc-Si panels have been considered. The electrical performance of the top and bottom panels operated in a mechanical stack has been obtained experimentally for various inter-panel separations in the range of 0-3 cm. Maximum output power density has been obtained for a separation of 0.75 cm. The mean value of output power density from CdTe (top panel) has been calculated as 32.3 Wm-2 and the mean value of output power density from μc-Si, the bottom panel of four-terminal photovoltaic system has been calculated as ˜3.5 Wm-2. Results reported in this study reveal the potential of mechanically stacked four-terminal tandem solar photovoltaic system towards an energy-efficient configuration.

The Italian programme in photovoltaic solar energy

NASA Astrophysics Data System (ADS)

Farinelli, U.

Italian programs and goals for developing a photovoltaic (PV) industry and market are outlined. It is suggested that only a few megawatts of PVs will be produced for domestic consumption in the next few years, while the largest market is for developing nations where costly diesel-fueled generators are used. The installation of PV systems in developing areas will permit testing and scaling up of production capacities from several MW to several hundred MW and then to GW annual production. Approximately 55,000,000 was devoted to government research in PV in 1982 and a PV research laboratory is being built near Naples.

Description of photovoltaic village power systems in the United States and Africa

NASA Technical Reports Server (NTRS)

Ratajczak, A. F.; Bifano, W. J.

1979-01-01

The paper describes the designs, hardware, and installations of NASA photovoltaic power systems in the village of Schuchuli in Arizona and Tangaye in Upper Volta, Africa. The projects were designed to demonstrate that current photovoltaic system technology can provide electrical power for domestic services for small, remote communities. The Schuchuli system has a 3.5 kW peak solar array which provides power for water pumping, a refrigerator for each family, lights, and community washing and sewing machines. The 1.8 kW Tangaye system provides power for pumping, flour milling, and lights in the milling building. Both are stand-alone systems operated by local personnel, and they are monitored by NASA to measure design adequacy and refine future designs.

Photovoltaic solar concentrator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat

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 themore » 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.« less

Substrate-induced interfacial plasmonics for photovoltaic conversion

PubMed Central

Li, Xinxi; Jia, Chuancheng; Ma, Bangjun; Wang, Wei; Fang, Zheyu; Zhang, Guoqing; Guo, Xuefeng

2015-01-01

Surface plasmon resonance (SPR) is widely used as light trapping schemes in solar cells, because it can concentrate light fields surrounding metal nanostructures and realize light management at the nanoscale. SPR in photovoltaics generally occurs at the metal/dielectric interfaces. A well-defined interface is therefore required to elucidate interfacial SPR processes. Here, we designed a photovoltaic device (PVD) with an atomically flat TiO2 dielectric/dye/graphene/metal nanoparticle (NP) interface for quantitatively studying the SPR enhancement of the photovoltaic conversion. Theoretical and experimental results indicated that the graphene monolayer was transparent to the electromagnetic field. This transparency led to significant substrate-induced plasmonic hybridization at the heterostructure interface. Combined with interparticle plasmonic coupling, the substrate-induced plasmonics concentrated light at the interface and enhanced the photo-excitation of dyes, thus improving the photoelectric conversion. Such a mechanistic understanding of interfacial plasmonic enhancement will further promote the development of efficient plasmon-enhanced solar cells and composite photocatalysts. PMID:26412576

Reflective photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lentine, Anthony L.; Nielson, Gregory N.; Cruz-Campa, Jose Luis

A photovoltaic module includes colorized reflective photovoltaic cells that act as pixels. The colorized reflective photovoltaic cells are arranged so that reflections from the photovoltaic cells or pixels visually combine into an image on the photovoltaic module. The colorized photovoltaic cell or pixel is composed of a set of 100 to 256 base color sub-pixel reflective segments or sub-pixels. The color of each pixel is determined by the combination of base color sub-pixels forming the pixel. As a result, each pixel can have a wide variety of colors using a set of base colors, which are created, from sub-pixel reflectivemore » segments having standard film thicknesses.« less

Perovskite and Organic Photovoltaics | Photovoltaic Research | NREL

Science.gov Websites

Perovskite and Organic Photovoltaics Perovskite and Organic Photovoltaics Scientist holds several solar cells; 2) electronic energy level alignment at the carbon nanotube/organic metal halide perovskite Hest in the PDIL in the S and TF at NREL. Organic Photovoltaics (OPV) We develop and apply new absorber

Surrogate Final Technical Report for "Solar: A Photovoltaic Manufacturing Development Facility"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farrar, Paul

2014-06-27

The project goal to create a first-of-a-kind crystalline Silicon (c-Si) photovoltaic (PV) Manufacturing & Technology Development Facility (MDF) that will support the growth and maturation of a strong domestic PV manufacturing industry, based on innovative and differentiated technology, by ensuring industry participants can, in a timely and cost-effective manner, access cutting-edge manufacturing equipment and production expertise needed to accelerate the transition of innovative technologies from R&D into manufacturing.

Photovoltaic evaluation study

NASA Astrophysics Data System (ADS)

Johnson, G.; Heikkilae, M.; Melasuo, T.; Spanner, S.

Realizing the value and potential of PV-power as well as the growing need for increased cooperation and sharing of knowledge in the field of photovoltaics, FINNIDA and UNICEF decided to undertake a study of selected PV-projects. There were two main objectives for the study: To gather, compile, evaluate and share information on the photovoltaic technology appropriate to developing countries, and to promote the interest and competence of Finnish research institutes, consultants and manufacturers in photovoltaic development. For this purpose a joint evaluation of significant, primarily UN-supported projects providing for the basic needs of rural communities was undertaken. The Gambia and Kenya offered a variety of such projects, and were chosen as target countries for the study. The projects were chosen to be both comparable and complimentary. In the Gambia, the main subject was a partially integrated health and telecommunications project, but a long-operating drinking water pumping system was also studied. In Kenya, a health project in the Turkana area was examined, and also a large scale water pumping installation for fish farming. Field visits were made in order to verify and supplement the data gathered through document research and earlier investigations. Individual data gathering sheets for the project form the core of this study and are intended to give the necessary information in an organized and accessible format. The findings could practically be condensed into one sentence: PV-systems work very well, if properly designed and installed, but the resources and requirements of the recipients must be considered to a higher degree.

MATLAB Simulation of Photovoltaic and Photovoltaic/Thermal Systems Performance

NASA Astrophysics Data System (ADS)

Nasir, Farah H. M.; Husaini, Yusnira

2018-03-01

The efficiency of the photovoltaic reduces when the photovoltaic cell temperature increased due to solar irradiance. One solution is come up with the cooling system photovoltaic system. This combination is forming the photovoltaic-thermal (PV/T) system. Not only will it generate electricity also heat at the same time. The aim of this research is to focus on the modeling and simulation of photovoltaic (PV) and photovoltaic-thermal (PV/T) electrical performance by using single-diode equivalent circuit model. Both PV and PV/T models are developed in Matlab/Simulink. By providing the cooling system in PV/T, the efficiency of the system can be increased by decreasing the PV cell temperature. The maximum thermal, electrical and total efficiency values of PV/T in the present research are 35.18%, 15.56% and 50.74% at solar irradiance of 400 W/m2, mass flow rate of 0.05kgs-1 and inlet temperature of 25 °C respectively has been obtained. The photovoltaic-thermal shows that the higher efficiency performance compared to the photovoltaic system.

Magnetic fields from domestic appliances in the UK

NASA Astrophysics Data System (ADS)

Preece, A. W.; Kaune, W.; Grainger, P.; Preece, S.; Golding, J.

1997-01-01

In a survey of 50 UK homes the 50 Hz fundamental and harmonic magnetic fields generated by 806 domestic appliances found in the homes, and used regularly by mothers, were measured. Measurements were made in the direction of most likely access, and from the surface of the appliances. Mothers completed a questionnaire on the use of appliances and were monitored for 24 h so that acquired exposure could be compared with the measured ambient fields in the home. Appliances were measured at standard distances and an algorithm was used to calculate fields at 100 and 50 cm to remove room background contributions. A few appliances generated fields in excess of at 1 m: microwave cookers ; washing machines ; dishwashers ; some electric showers and can openers . Of continuously operating devices, only central heating pumps (), central heating boilers () and fish-tank air pumps () produced significant fields at 0.5 m. There were no obvious ways to group different types of appliances as high- or low-strength sources. Mothers spent on average about 4.5 h per day in the kitchen, where the strongest sources of magnetic field were located.

Photovoltaic effect in Bi{sub 2}TeO{sub 5} photorefractive crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliveira, Ivan de, E-mail: ivan@ft.unicamp.brg; Capovilla, Danilo Augusto; Carvalho, Jesiel F.

2015-10-12

We report on the presence of a strong photovoltaic effect on nominally undoped photorefractive Bi{sub 2}TeO{sub 5} crystals and estimated their Glass photovoltaic constant and photovoltaic field for λ = 532 nm illumination. We directly measured the photovoltaic-based photocurrent in this material under λ = 532 nm wavelength laser light illumination and compared its behavior with that of a well known photovoltaic Fe-doped Lithium Niobate crystal. We also show the photovoltaic current to strongly depend on the polarization direction of light. Holographic diffraction efficiency oscillation during recording and the behavior of fringe-locked running holograms in self-stabilized experiments are also demonstrated here as additional indirect proofs ofmore » the photovoltaic nature of this material.« less

Qualification testing of flat-plate photovoltaic modules

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Griffith, J. S.; Ross, R. G., Jr.

1982-01-01

The placement of photovoltaic modules in various applications, in climates and locations throughout the world, results in different degrees and combinations of environmental and electrical stress. Early detection of module reliability deficiencies via laboratory testing is necessary for achieving long, satisfactory field service. This overview paper describes qualification testing techniques being used in the US Department of Energy's flat-plate terrestrial photovoltaic development program in terms of their significance, rationale for specified levels and durations, and test results.

Thin Film Photovoltaic Partnership Project | Photovoltaic Research | NREL

Science.gov Websites

Thin Film Photovoltaic Partnership Project Thin Film Photovoltaic Partnership Project NREL's Thin Film Photovoltaic (PV) Partnership Project led R&D on emerging thin-film solar technologies in the National Laboratory developed low-cost transparent encapsulation schemes for CIGS cells that reduced power

Photovoltaic cell and production thereof

DOEpatents

Narayanan, Srinivasamohan [Gaithersburg, MD; Kumar, Bikash [Bangalore, IN

2008-07-22

An efficient photovoltaic cell, and its process of manufacture, is disclosed wherein the back surface p-n junction is removed from a doped substrate having an oppositely doped emitter layer. A front surface and edges and optionally the back surface periphery are masked and a back surface etch is performed. The mask is not removed and acts as an anti-reflective coating, a passivating agent, or both. The photovoltaic cell retains an untextured back surface whether or not the front is textured and the dopant layer on the back surface is removed to enhance the cell efficiency. Optionally, a back surface field is formed.

Multi angle laser light scattering evaluation of field exposed thermoplastic photovoltaic encapsulant materials

DOE PAGES

Kempe, Michael D.; Miller, David C.; Wohlgemuth, John H.; ...

2016-01-08

As creep of polymeric materials is potentially a safety concern for photovoltaic modules, the potential for module creep has become a significant topic of discussion in the development of IEC 61730 and IEC 61215. To investigate the possibility of creep, modules were constructed, using several thermoplastic encapsulant materials, into thin-film mock modules and deployed in Mesa, Arizona. The materials examined included poly(ethylene)-co-vinyl acetate (EVA, including formulations both cross-linked and with no curing agent), polyethylene/polyoctene copolymer (PO), poly(dimethylsiloxane) (PDMS), polyvinyl butyral (PVB), and thermoplastic polyurethane (TPU). The absence of creep in this experiment is attributable to several factors of which themore » most notable one was the unexpected cross-linking of an EVA formulation without a cross-linking agent. It was also found that some materials experienced both chain scission and cross-linking reactions, sometimes with a significant dependence on location within a module. The TPU and EVA samples were found to degrade with cross-linking reactions dominating over chain scission. In contrast, the PO materials degraded with chain scission dominating over cross-linking reactions. Furthermore, we found no significant indications that viscous creep is likely to occur in fielded modules capable of passing the qualification tests, we note that one should consider how a polymer degrades, chain scission or cross-linking, in assessing the suitability of a thermoplastic polymer in terrestrial photovoltaic applications.« less

National Center for Photovoltaics | Photovoltaic Research | NREL

Science.gov Websites

drive industry growth in U.S. photovoltaic (PV) manufacturing. The NCPV includes multiple capabilities in PV research, development, deployment, and outreach. To help the U.S. photovoltaic industry

Company Partners in Photovoltaic Manufacturing R&D | Photovoltaic Research

Science.gov Websites

| NREL Company Partners in Photovoltaic Manufacturing R&D Company Partners in Photovoltaic Manufacturing R&D More than 40 private-sector companies partnered with NREL on successful Global Photovoltaic Specialists Global Solar Energy Golden Photon Iowa Thin Film Technologies ITN Energy

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.

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.

Photovoltaic device

DOEpatents

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

2017-03-21

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.

Emerging Novel Metal Electrodes for Photovoltaic Applications.

PubMed

Lu, Haifei; Ren, Xingang; Ouyang, Dan; Choy, Wallace C H

2018-04-01

Emerging novel metal electrodes not only serve as the collector of free charge carriers, but also function as light trapping designs in photovoltaics. As a potential alternative to commercial indium tin oxide, transparent electrodes composed of metal nanowire, metal mesh, and ultrathin metal film are intensively investigated and developed for achieving high optical transmittance and electrical conductivity. Moreover, light trapping designs via patterning of the back thick metal electrode into different nanostructures, which can deliver a considerable efficiency improvement of photovoltaic devices, contribute by the plasmon-enhanced light-mattering interactions. Therefore, here the recent works of metal-based transparent electrodes and patterned back electrodes in photovoltaics are reviewed, which may push the future development of this exciting field. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photovoltaic module and laminate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunea, Gabriela E.; Kim, Sung Dug; Kavulak, David F.J.

A photovoltaic module is disclosed. The photovoltaic module has a first side directed toward the sun during normal operation and a second, lower side. The photovoltaic module comprises a perimeter frame and a photovoltaic laminate at least partially enclosed by and supported by the perimeter frame. The photovoltaic laminate comprises a transparent cover layer positioned toward the first side of the photovoltaic module, an upper encapsulant layer beneath and adhering to the cover layer, a plurality of photovoltaic solar cells beneath the upper encapsulant layer, the photovoltaic solar cells electrically interconnected, a lower encapsulant layer beneath the plurality of photovoltaicmore » solar cells, the upper and lower encapsulant layers enclosing the plurality of photovoltaic solar cells, and a homogenous rear environmental protection layer, the rear environmental protection layer adhering to the lower encapsulant layer, the rear environmental protection layer exposed to the ambient environment on the second side of the photovoltaic module.« less

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.

Photovoltaic effect and photopolarization in Pb [(Mg1/3Nb2/3) 0.68Ti0.32] O3 crystal

NASA Astrophysics Data System (ADS)

Makhort, A. S.; Chevrier, F.; Kundys, D.; Doudin, B.; Kundys, B.

2018-01-01

Ferroelectric materials are an alternative to semiconductor-based photovoltaics and offer the advantage of above bandgap photovoltage generation. However, there are few known compounds, and photovoltaic efficiencies remain low. Here, we report the discovery of a photovoltaic effect in undoped lead magnesium niobate-lead titanate crystal and a significant improvement in the photovoltaic response under suitable electric fields and temperatures. The photovoltaic effect is maximum near the electric-field-driven ferroelectric dipole reorientation, and increases threefold near the Curie temperature (Tc). Moreover, at ferroelectric saturation, the photovoltaic response exhibits clear remanent and transient effects. The transient-remanent combinations together with electric and thermal tuning possibilities indicate photoferroelectric crystals as emerging elements for photovoltaics and optoelectronics, relevant to all-optical information storage and beyond.

Long-term leaching of photovoltaic modules

NASA Astrophysics Data System (ADS)

Nover, Jessica; Zapf-Gottwick, Renate; Feifel, Carolin; Koch, Michael; Metzger, Jörg W.; Werner, Jürgen H.

2017-08-01

Some photovoltaic module technologies use toxic materials. We report long-term leaching on photovoltaic module pieces of 5 × 5 cm2 size. The pieces are cut out from modules of the four major commercial photovoltaic technologies: crystalline and amorphous silicon, cadmium telluride as well as from copper indium gallium diselenide. To simulate different environmental conditions, leaching occurs at room temperature in three different water-based solutions with pH 3, 7, and 11. No agitation is performed to simulate more representative field conditions. After 360 days, about 1.4% of lead from crystalline silicon module pieces and 62% of cadmium from cadmium telluride module pieces are leached out in acidic solutions. The leaching depends heavily on the pH and the redox potential of the aqueous solutions and it increases with time. The leaching behavior is predictable by thermodynamic stability considerations. These predictions are in good agreement with the experimental results.

Automated installation methods for photovoltaic arrays

NASA Astrophysics Data System (ADS)

Briggs, R.; Daniels, A.; Greenaway, R.; Oster, J., Jr.; Racki, D.; Stoeltzing, R.

1982-11-01

Since installation expenses constitute a substantial portion of the cost of a large photovoltaic power system, methods for reduction of these costs were investigated. The installation of the photovoltaic arrays includes all areas, starting with site preparation (i.e., trenching, wiring, drainage, foundation installation, lightning protection, grounding and installation of the panel) and concluding with the termination of the bus at the power conditioner building. To identify the optimum combination of standard installation procedures and automated/mechanized techniques, the installation process was investigated including the equipment and hardware available, the photovoltaic array structure systems and interfaces, and the array field and site characteristics. Preliminary designs of hardware for both the standard installation method, the automated/mechanized method, and a mix of standard installation procedures and mechanized procedures were identified to determine which process effectively reduced installation costs. In addition, costs associated with each type of installation method and with the design, development and fabrication of new installation hardware were generated.

Environmental aging in polycrystalline-Si photovoltaic modules: comparison of chamber-based accelerated degradation studies with field-test data

NASA Astrophysics Data System (ADS)

Lai, T.; Biggie, R.; Brooks, A.; Potter, B. G.; Simmons-Potter, K.

2015-09-01

Lifecycle degradation testing of photovoltaic (PV) modules in accelerated-degradation chambers can enable the prediction both of PV performance lifetimes and of return-on-investment for installations of PV systems. With degradation results strongly dependent on chamber test parameters, the validity of such studies relative to fielded, installed PV systems must be determined. In the present work, accelerated aging of a 250 W polycrystalline silicon module is compared to real-time performance degradation in a similar polycrystalline-silicon, fielded, PV technology that has been operating since October 2013. Investigation of environmental aging effects are performed in a full-scale, industrial-standard environmental chamber equipped with single-sun irradiance capability providing illumination uniformity of 98% over a 2 x 1.6 m area. Time-dependent, photovoltaic performance (J-V) is evaluated over a recurring, compressed night-day cycle providing representative local daily solar insolation for the southwestern United States, followed by dark (night) cycling. This cycle is synchronized with thermal and humidity environmental variations that are designed to mimic, as closely as possible, test-yard conditions specific to a 12 month weather profile for a fielded system in Tucson, AZ. Results confirm the impact of environmental conditions on the module long-term performance. While the effects of temperature de-rating can be clearly seen in the data, removal of these effects enables the clear interpretation of module efficiency degradation with time and environmental exposure. With the temperature-dependent effect removed, the normalized efficiency is computed and compared to performance results from another panel of similar technology that has previously experienced identical climate changes in the test yard. Analysis of relative PV module efficiency degradation for the chamber-tested system shows good comparison to the field-tested system with ~2.5% degradation following

Photovoltaic system criteria documents. Volume 5: Safety criteria for photovoltaic applications

NASA Technical Reports Server (NTRS)

Koenig, John C.; Billitti, Joseph W.; Tallon, John M.

1979-01-01

Methodology is described for determining potential safety hazards involved in the construction and operation of photovoltaic power systems and provides guidelines for the implementation of safety considerations in the specification, design and operation of photovoltaic systems. Safety verification procedures for use in solar photovoltaic systems are established.

Customized color patterning of photovoltaic cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cruz-Campa, Jose Luis; Nielson, Gregory N.; Okandan, Murat

Photovoltaic cells and photovoltaic modules, as well as methods of making and using such photovoltaic cells and photovoltaic modules, are disclosed. More particularly, embodiments of the photovoltaic cells selectively reflect visible light to provide the photovoltaic cells with a colorized appearance. Photovoltaic modules combining colorized photovoltaic cells may be used to harvest solar energy while providing a customized appearance, e.g., an image or pattern.

Flexo-photovoltaic effect

NASA Astrophysics Data System (ADS)

Yang, Ming-Min; Kim, Dong Jik; Alexe, Marin

2018-05-01

It is highly desirable to discover photovoltaic mechanisms that enable enhanced efficiency of solar cells. Here we report that the bulk photovoltaic effect, which is free from the thermodynamic Shockley-Queisser limit but usually manifested only in noncentrosymmetric (piezoelectric or ferroelectric) materials, can be realized in any semiconductor, including silicon, by mediation of flexoelectric effect. We used either an atomic force microscope or a micrometer-scale indentation system to introduce strain gradients, thus creating very large photovoltaic currents from centrosymmetric single crystals of strontium titanate, titanium dioxide, and silicon. This strain gradient–induced bulk photovoltaic effect, which we call the flexo-photovoltaic effect, functions in the absence of a p-n junction. This finding may extend present solar cell technologies by boosting the solar energy conversion efficiency from a wide pool of established semiconductors.

Environmental testing of terrestrial flat plate photovoltaic modules

NASA Technical Reports Server (NTRS)

Hoffman, A.; Griffith, J.

1979-01-01

The Low-Cost Solar Array (LSA) Project at the Jet Propulsion Laboratory has as one objective: the development and implementation of environmental tests for flat plate photovoltaic modules as part of the Department of Energy's terrestrial photovoltaic program. Modules procured under this program have been subjected to a variety of laboratory tests intended to simulate service environments, and the results of these tests have been compared to available data from actual field service. This comparison indicates that certain tests (notably temperature cycling, humidity cycling, and cyclic pressure loading) are effective indicators of some forms of field failures. Other tests have yielded results useful in formulating module design guidelines. Not all effects noted in field service have been successfully reproduced in the laboratory, however, and work is continuing in order to improve the value of the test program as a tool for evaluating module design and workmanship. This paper contains a review of these ongoing efforts and an assessment of significant test results to date.

Treated domestic sewage irrigation significantly decreased the CH4, N2O and NH3 emissions from paddy fields with straw incorporation

NASA Astrophysics Data System (ADS)

Xu, Shanshan; Hou, Pengfu; Xue, Lihong; Wang, Shaohua; Yang, Linzhang

2017-11-01

Straw incorporation and domestic sewage irrigation have been recommended as an environmentally friendly agricultural practice and are widely used not only in China but also in other countries. The individual effects on yield and environmental impacts have been studied extensively, but the comprehensive effect when straw returning and domestic sewage irrigation are combined together has seldom been reported. This study was conducted to examine the effects of straw returning and domestic sewage irrigation on rice yields, greenhouse gas emissions (GHGs) and ammonia (NH3) volatilization from paddy fields from 2015 to 2016. The results showed that the rice yield was not affected by the irrigation water sources and straw returning under the same total N input, which was similar in both years. Due to the rich N in the domestic sewage, domestic sewage irrigation could reduce approximately 45.2% of chemical nitrogen fertilizer input without yield loss. Compared to straw removal treatments, straw returning significantly increased the CH4 emissions by approximately 7-9-fold under domestic sewage irrigation and 13-14-fold under tap water irrigation. Straw returning also increased the N2O emissions under the two irrigation water types. In addition, the seasonal NH3 volatilization loss was significantly increased by 88.8% and 61.2% under straw returning compared to straw removal in 2015 and 2016, respectively. However, domestic sewage irrigation could decrease CH4 emissions by 24.5-26.6%, N2O emissions by 37.0-39.0% and seasonal NH3 volatilization loss by 27.2-28.3% under straw returning compared to tap water irrigation treatments. Global warming potentials (GWP) and greenhouse gas intensities (GHGI) were significantly increased with straw returning compared with those of straw removal, while they were decreased by domestic sewage irrigation under straw returning compared to tap water irrigation. Significant interactions between straw returning and domestic sewage irrigation on

Recent Advances in Wide-Bandgap Photovoltaic Polymers.

PubMed

Cai, Yunhao; Huo, Lijun; Sun, Yanming

2017-06-01

The past decade has witnessed significant advances in the field of organic solar cells (OSCs). Ongoing improvements in the power conversion efficiency of OSCs have been achieved, which were mainly attributed to the design and synthesis of novel conjugated polymers with different architectures and functional moieties. Among various conjugated polymers, the development of wide-bandgap (WBG) polymers has received less attention than that of low-bandgap and medium-bandgap polymers. Here, we briefly summarize recent advances in WBG polymers and their applications in organic photovoltaic (PV) devices, such as tandem, ternary, and non-fullerene solar cells. Addtionally, we also dissuss the application of high open-circuit voltage tandem solar cells in PV-driven electrochemical water dissociation. We mainly focus on the molecular design strategies, the structure-property correlations, and the photovoltaic performance of these WBG polymers. Finally, we extract empirical regularities and provide invigorating perspectives on the future development of WBG photovoltaic materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermionic photovoltaic energy converter

NASA Technical Reports Server (NTRS)

Chubb, D. L. (Inventor)

1985-01-01

A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

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.

Organic Photovoltaic Multiferroics

DTIC Science & Technology

2016-01-14

Aug-2014 31-Jul-2017 Approved for Public Release; Distribution Unlimited Final Report: ARO-YIP (Materials By Design): Organic Photovoltaic ...Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Materials design, self-assembly, magnetoelectrics, photovoltaics REPORT...7552 31-Jul-2017 ABSTRACT Final Report: ARO-YIP (Materials By Design): Organic Photovoltaic Multiferroics Report Title In this project, we aim at

Photovoltaic Performance and Reliability Workshop summary

NASA Astrophysics Data System (ADS)

Kroposki, Benjamin

1997-02-01

The objective of the Photovoltaic Performance and Reliability Workshop was to provide a forum where the entire photovoltaic (PV) community (manufacturers, researchers, system designers, and customers) could get together and discuss technical issues relating to PV. The workshop included presentations from twenty-five speakers and had more than one hundred attendees. This workshop also included several open sessions in which the audience and speakers could discuss technical subjects in depth. Several major topics were discussed including: PV characterization and measurements, service lifetimes for PV devices, degradation and failure mechanisms for PV devices, standardization of testing procedures, AC module performance and reliability testing, inverter performance and reliability testing, standardization of utility interconnect requirements, experience from field deployed systems, and system certification.

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.

Photovoltaic remote instrument applications: Assessment of the near-term market

NASA Technical Reports Server (NTRS)

Rosenblum, L.; Scudder, L. R.; Poley, W. A.; Bifano, W. J.

1977-01-01

A preliminary assessment of the near term market for photovoltaic remote instrument applications is presented. Among the potential users, two market sectors are considered: government and private. However, the majority of the remote systems studied are operated by or for the federal, state, or local governments. Environmental monitoring and surveillance remote instrument systems are discussed. Based on information obtained in this preliminary market survey, a domestic, civilian market of at least 1.3 MW sub pk is forecast for remote instrument systems. This estimate is exclusive of several potentially large scale markets for remote instruments which are identified but for which no hard data is available.

Tandem junction amorphous semiconductor photovoltaic cell

DOEpatents

Dalal, Vikram L.

1983-01-01

A photovoltaic stack comprising at least two p.sup.+ i n.sup.+ cells in optical series, said cells separated by a transparent ohmic contact layer(s), provides a long optical path for the absorption of photons while preserving the advantageous field-enhanced minority carrier collection arrangement characteristic of p.sup.+ i n.sup.+ cells.

Molecular Photovoltaics in Nanoscale Dimension

PubMed Central

Burtman, Vladimir; Zelichonok, Alexander; Pakoulev, Andrei V.

2011-01-01

This review focuses on the intrinsic charge transport in organic photovoltaic (PVC) devices and field-effect transistors (SAM-OFETs) fabricated by vapor phase molecular self-assembly (VP-SAM) method. The dynamics of charge transport are determined and used to clarify a transport mechanism. The 1,4,5,8-naphthalene-tetracarboxylic diphenylimide (NTCDI) SAM devices provide a useful tool to study the fundamentals of polaronic transport at organic surfaces and to discuss the performance of organic photovoltaic devices in nanoscale. Time-resolved photovoltaic studies allow us to separate the charge annihilation kinetics in the conductive NTCDI channel from the overall charge kinetic in a SAM-OFET device. It has been demonstrated that tuning of the type of conductivity in NTCDI SAM-OFET devices is possible by changing Si substrate doping. Our study of the polaron charge transfer in organic materials proposes that a cation-radical exchange (redox) mechanism is the major transport mechanism in the studied SAM-PVC devices. The role and contribution of the transport through delocalized states of redox active surface molecular aggregates of NTCDI are exposed and investigated. This example of technological development is used to highlight the significance of future technological development of nanotechnologies and to appreciate a structure-property paradigm in organic nanostructures. PMID:21339983

Flexo-photovoltaic effect.

PubMed

Yang, Ming-Min; Kim, Dong Jik; Alexe, Marin

2018-05-25

It is highly desirable to discover photovoltaic mechanisms that enable enhanced efficiency of solar cells. Here we report that the bulk photovoltaic effect, which is free from the thermodynamic Shockley-Queisser limit but usually manifested only in noncentrosymmetric (piezoelectric or ferroelectric) materials, can be realized in any semiconductor, including silicon, by mediation of flexoelectric effect. We used either an atomic force microscope or a micrometer-scale indentation system to introduce strain gradients, thus creating very large photovoltaic currents from centrosymmetric single crystals of strontium titanate, titanium dioxide, and silicon. This strain gradient-induced bulk photovoltaic effect, which we call the flexo-photovoltaic effect, functions in the absence of a p-n junction. This finding may extend present solar cell technologies by boosting the solar energy conversion efficiency from a wide pool of established semiconductors. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Emerging photovoltaic module technologies at PVUSA: A five-year assessment

NASA Astrophysics Data System (ADS)

Townsend, Tim

1995-04-01

The Photovoltaics for Utility Scale Applications (PVUSA) project tests two types of photovoltaic systems: new modules fielded as 20-kW emerging module technology (EMT) arrays, and more mature technologies fielded as 20- to 500-kW turnkey utility scale (US) systems. This report summarizes experiences of the PVUSA project in operating the first six 20-kW EMT photovoltaic systems. Five systems are installed at Davis, California, and one at Kihei, Hawaii. Products selected for testing and demonstration were judged to have potential for significant technical advancement or reduction in manufacturing cost. Features leading to selection of each system and findings over the average 5 years of operation are compared in the report. Factory product qualification test experiences along with field acceptance test results are documented. Evaluation includes a broad range of performance parameters, including long-term efficiency, seasonal generation patterns, and maintenance. While some of the arrays have operated as well as any commercial system, others have fared poorly. Throughout the procurement and operation of these precommercial PV modules, PVUSA has provided feedback to vendors, critical for product improvement. The data and evaluations in this report will be of further benefit to manufacturers and provide general comparative information on a variety of technologies to researchers in utilities, government, and industry alike.

Massive ordering and alignment of cylindrical micro-objects by photovoltaic optoelectronic tweezers.

PubMed

Elvira, Iris; Muñoz-Martínez, Juan F; Barroso, Álvaro; Denz, Cornelia; Ramiro, José B; García-Cabañes, Angel; Agulló-López, Fernando; Carrascosa, Mercedes

2018-01-01

Optical tools for manipulation and trapping of micro- and nano-objects are a fundamental issue for many applications in nano- and biotechnology. This work reports on the use of one such method, known as photovoltaic optoelectronics tweezers, to orientate and organize cylindrical microcrystals, specifically elongated zeolite L, on the surface of Fe-doped LiNbO 3 crystal plates. Patterns of aligned zeolites have been achieved through the forces and torques generated by the bulk photovoltaic effect. The alignment patterns with zeolites parallel or perpendicular to the substrate surface are highly dependent on the features of light distribution and crystal configuration. Moreover, dielectrophoretic chains of zeolites with lengths up to 100 μm have often been observed. The experimental results of zeolite trapping and alignment have been discussed and compared together with theoretical simulations of the evanescent photovoltaic electric field and the dielectrophoretic potential. They demonstrate the remarkable capabilities of the optoelectronic photovoltaic method to orientate and pattern anisotropic microcrystals. The combined action of patterning and alignment offers a unique tool to prepare functional nanostructures with potential applications in a variety of fields such as nonlinear optics or plasmonics.

Market definition study of photovoltaic power for remote villages in the United States

NASA Technical Reports Server (NTRS)

Ragsdale, C.; Quashie, P.

1980-01-01

A grass roots evaluation of the market potential was carried out for photovoltaic applications in remote villages in the U. S. and its possessions. An estimate of almost 14 MWp available for conversion from a potential to a real market was defined. The total power potential was based on the energy needs of almost 400 sites reported by Federal agencies and inputs from over 100 Indian tribes. The methodology used, the results achieved, and some recommendations of how to convert this domestic market potential into a real market are detailed.

Tandem junction amorphous semiconductor photovoltaic cell

DOEpatents

Dalal, V.L.

1983-06-07

A photovoltaic stack comprising at least two p[sup +]i n[sup +] cells in optical series, said cells separated by a transparent ohmic contact layer(s), provides a long optical path for the absorption of photons while preserving the advantageous field-enhanced minority carrier collection arrangement characteristic of p[sup +]i n[sup +] cells. 3 figs.

Reliability and Engineering | Photovoltaic Research | NREL

Science.gov Websites

-Time PV and Solar Resource Testing We study long-term performance, reliability, and failures of PV (NCPV) at NREL, we focus on photovoltaic (PV) reliability research and development (R&D) to improve PV technologies. We test modules and systems for long-term performance and stress them in the field

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.

Photovoltaic device and method

DOEpatents

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.

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.

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.

Current perspectives and the future of domestication studies

PubMed Central

Larson, Greger; Piperno, Dolores R.; Allaby, Robin G.; Purugganan, Michael D.; Andersson, Leif; Arroyo-Kalin, Manuel; Barton, Loukas; Climer Vigueira, Cynthia; Denham, Tim; Dobney, Keith; Doust, Andrew N.; Gepts, Paul; Gilbert, M. Thomas P.; Gremillion, Kristen J.; Lucas, Leilani; Lukens, Lewis; Marshall, Fiona B.; Olsen, Kenneth M.; Pires, J. Chris; Richerson, Peter J.; Rubio de Casas, Rafael; Sanjur, Oris I.; Thomas, Mark G.; Fuller, Dorian Q.

2014-01-01

It is difficult to overstate the cultural and biological impacts that the domestication of plants and animals has had on our species. Fundamental questions regarding where, when, and how many times domestication took place have been of primary interest within a wide range of academic disciplines. Within the last two decades, the advent of new archaeological and genetic techniques has revolutionized our understanding of the pattern and process of domestication and agricultural origins that led to our modern way of life. In the spring of 2011, 25 scholars with a central interest in domestication representing the fields of genetics, archaeobotany, zooarchaeology, geoarchaeology, and archaeology met at the National Evolutionary Synthesis Center to discuss recent domestication research progress and identify challenges for the future. In this introduction to the resulting Special Feature, we present the state of the art in the field by discussing what is known about the spatial and temporal patterns of domestication, and controversies surrounding the speed, intentionality, and evolutionary aspects of the domestication process. We then highlight three key challenges for future research. We conclude by arguing that although recent progress has been impressive, the next decade will yield even more substantial insights not only into how domestication took place, but also when and where it did, and where and why it did not. PMID:24757054

Solar Photovoltaic Technology Basics | NREL

Science.gov Websites

For more information about solar photovoltaic energy, visit the following resources: Solar PV Photovoltaic Technology Basics Solar Photovoltaic Technology Basics Solar cells, also called photovoltaic (PV) cells by scientists, convert sunlight directly into electricity. PV gets its name from the

Testing flat plate photovoltaic modules for terrestrial environment

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Arnett, J. C.; Ross, R. G., Jr.

1979-01-01

New qualification tests have been developed for flat plate photovoltaic modules. Temperature cycling, cyclic pressure load, and humidity exposure are especially useful for detecting design and fabrication deficiencies. There is positive correlation between many of the observed field effects, such as power loss, and qualification test induced degradation. The status of research efforts for the development of test methodology for field-related problems is reviewed.

Giant photovoltaic response in band engineered ferroelectric perovskite.

PubMed

Pal, Subhajit; Swain, Atal Bihari; Biswas, Pranab Parimal; Murali, D; Pal, Arnab; Nanda, B Ranjit K; Murugavel, Pattukkannu

2018-05-22

Recently the solar energy, an inevitable part of green energy source, has become a mandatory topics in frontier research areas. In this respect, non-centrosymmetric ferroelectric perovskites with open circuit voltage (V OC ) higher than the bandgap, gain tremendous importance as next generation photovoltaic materials. Here a non-toxic co-doped Ba 1-x (Bi 0.5 Li 0.5 ) x TiO 3 ferroelectric system is designed where the dopants influence the band topology in order to enhance the photovoltaic effect. In particular, at the optimal doping concentration (x opt  ~ 0.125) the sample reveals a remarkably high photogenerated field E OC  = 320 V/cm (V OC  = 16 V), highest ever reported in any bulk polycrystalline non-centrosymmetric systems. The band structure, examined through DFT calculations, suggests that the shift current mechanism is key to explain the large enhancement in photovoltaic effect in this family.

Towards large-scale deployment of bifacial photovoltaics

NASA Astrophysics Data System (ADS)

Kopecek, R.; Libal, J.

2018-06-01

Low photovoltaic module costs imply that increasing the energy yield per module area is now a priority. We argue that modules harvesting sunlight from both sides will strongly penetrate the market but that more field data, better simulation tools and international measurement standards are needed to overcome perceived investment risks.

Controllable Photovoltaic Effect of Microarray Derived from Epitaxial Tetragonal BiFeO3 Films.

PubMed

Lu, Zengxing; Li, Peilian; Wan, Jian-Guo; Huang, Zhifeng; Tian, Guo; Pan, Danfeng; Fan, Zhen; Gao, Xingsen; Liu, Jun-Ming

2017-08-16

Recently, the ferroelectric photovoltaic (FePV) effect has attracted great interest due to its potential in developing optoelectronic devices such as solar cell and electric-optical sensors. It is important for actual applications to realize a controllable photovoltaic process in ferroelectric-based materials. In this work, we prepared well-ordered microarrays based on epitaxially tetragonal BiFeO 3 (T-BFO) films by the pulsed laser deposition technique. The polarization-dependent photocurrent image was directly observed by a conductive atomic force microscope under ultraviolet illumination. By choosing a suitable buffer electrode layer and controlling the ferroelectric polarization in the T-BFO layer, we realized the manipulation of the photovoltaic process. Moreover, based on the analysis of the band structure, we revealed the mechanism of manipulating the photovoltaic process and attributed it to the competition between two key factors, i.e., the internal electric field caused by energy band alignments at interfaces and the depolarization field induced by the ferroelectric polarization in T-BFO. This work is very meaningful for deeply understanding the photovoltaic process of BiFeO 3 -based devices at the microscale and provides us a feasible avenue for developing data storage or logic switching microdevices based on the FePV effect.

Toward Switchable Photovoltaic Effect via Tailoring Mobile Oxygen Vacancies in Perovskite Oxide Films.

PubMed

Ge, Chen; Jin, Kui-Juan; Zhang, Qing-Hua; Du, Jian-Yu; Gu, Lin; Guo, Hai-Zhong; Yang, Jing-Ting; Gu, Jun-Xing; He, Meng; Xing, Jie; Wang, Can; Lu, Hui-Bin; Yang, Guo-Zhen

2016-12-21

The defect chemistry of perovskite oxides involves the cause to most of their abundant functional properties, including interface magnetism, charge transport, ionic exchange, and catalytic activity. The possibility to achieve dynamic control over oxygen anion vacancies offers a unique opportunity for the development of appealing switchable devices, which at present are commonly based on ferroelectric materials. Herein, we report the discovery of a switchable photovoltaic effect, that the sign of the open voltage and the short circuit current can be reversed by inverting the polarity of the applied field, upon electrically tailoring the distribution of oxygen vacancies in perovskite oxide films. This phenomenon is demonstrated in lateral photovoltaic devices based on both ferroelectric BiFeO 3 and paraelectric SrTiO 3 films, under a reversed applied field whose magnitude is much smaller than the coercivity value of BiFeO 3 . The migration of oxygen vacancies was directly observed by employing an advanced annular bright-field scanning transmission electron microscopy technique with in situ biasing equipment. We conclude that the band bending induced by the motion of oxygen vacancies is the driving force for the reversible switching between two photovoltaic states. The present work can provide an active path for the design of novel switchable photovoltaic devices with a wide range of transition metal oxides in terms of the ionic degrees of freedom.

Real-Time Photovoltaic and Solar Resource Testing | Photovoltaic Research |

Science.gov Websites

community toward developing comprehensive PV standards. Each year, NCPV researchers, along with solar performance Bill Marion: Solar radiation resource information, and PV module and system performance modeling NREL Real-Time Photovoltaic and Solar Resource Testing Real-Time Photovoltaic and Solar

Organic Semiconductor Photovoltaics

NASA Astrophysics Data System (ADS)

Sariciftci, Niyazi Serdar

2005-03-01

Recent developments on organic photovoltaic elements are reviewed. Semiconducting conjugated polymers and molecules as well as nanocrystalline inorganic semiconductors are used in composite thin films. The photophysics of such photoactive devices is based on the photoinduced charge transfer from donor type semiconducting molecules onto acceptor type molecules such as Buckminsterfullerene, C60 and/or nanoparticles. Similar to the first steps in natural photosynthesis, this photoinduced electron transfer leads to a number of potentially interesting applications which include sensitization of the photoconductivity and photovoltaic phenomena. Examples of photovoltaic architectures are discussed with their potential in terrestrial solar energy conversion. Several materials are introduced and discussed for their photovoltaic activities. Furthermore, nanomorphology has been investigated with AFM, SEM and TEM. The morphology/property relationship for a given photoactive system is found to be a major effect.

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.

Awards for Photovoltaic Manufacturing R&D | Photovoltaic Research | NREL

Science.gov Websites

Awards for Photovoltaic Manufacturing R&D Awards for Photovoltaic Manufacturing R&D The following research efforts within the PV Manufacturing R&D Project were honored with prestigious industry awards. 1995-AstroPower (now GE Energy): Received an R&D 100 Award for its Silicon-Film

Graphene quantum dot (GQD)-induced photovoltaic and photoelectric memory elements in a pentacene/GQD field effect transistor as a probe of functional interface

NASA Astrophysics Data System (ADS)

Kim, Youngjun; Cho, Seongeun; Kim, Hyeran; Seo, Soonjoo; Lee, Hyun Uk; Lee, Jouhahn; Ko, Hyungduk; Chang, Mincheol; Park, Byoungnam

2017-09-01

Electric field-induced charge trapping and exciton dissociation were demonstrated at a penatcene/grapheme quantum dot (GQD) interface using a bottom contact bi-layer field effect transistor (FET) as an electrical nano-probe. Large threshold voltage shift in a pentacene/GQD FET in the dark arises from field-induced carrier trapping in the GQD layer or GQD-induced trap states at the pentacene/GQD interface. As the gate electric field increases, hysteresis characterized by the threshold voltage shift depending on the direction of the gate voltage scan becomes stronger due to carrier trapping associated with the presence of a GQD layer. Upon illumination, exciton dissociation and gate electric field-induced charge trapping simultaneously contribute to increase the threshold voltage window, which can potentially be exploited for photoelectric memory and/or photovoltaic devices through interface engineering.

Light Harvesting for Organic Photovoltaics

PubMed Central

2016-01-01

The field of organic photovoltaics has developed rapidly over the last 2 decades, and small solar cells with power conversion efficiencies of 13% have been demonstrated. Light absorbed in the organic layers forms tightly bound excitons that are split into free electrons and holes using heterojunctions of electron donor and acceptor materials, which are then extracted at electrodes to give useful electrical power. This review gives a concise description of the fundamental processes in photovoltaic devices, with the main emphasis on the characterization of energy transfer and its role in dictating device architecture, including multilayer planar heterojunctions, and on the factors that impact free carrier generation from dissociated excitons. We briefly discuss harvesting of triplet excitons, which now attracts substantial interest when used in conjunction with singlet fission. Finally, we introduce the techniques used by researchers for characterization and engineering of bulk heterojunctions to realize large photocurrents, and examine the formed morphology in three prototypical blends. PMID:27951633

Enhancement of Local Photovoltaic Current at Ferroelectric Domain Walls in BiFeO3.

PubMed

Yang, Ming-Min; Bhatnagar, Akash; Luo, Zheng-Dong; Alexe, Marin

2017-02-20

Domain walls, which are intrinsically two dimensional nano-objects exhibiting nontrivial electronic and magnetic behaviours, have been proven to play a crucial role in photovoltaic properties of ferroelectrics. Despite this recognition, the electronic properties of domain walls under illumination until now have been accessible only to macroscopic studies and their effects upon the conduction of photovoltaic current still remain elusive. The lack of understanding hinders the developing of nanoscale devices based on ferroelectric domain walls. Here, we directly characterize the local photovoltaic and photoconductive properties of 71° domain walls on BiFeO 3 thin films with a nanoscale resolution. Local photovoltaic current, proven to be driven by the bulk photovoltaic effect, has been probed over the whole illuminated surface by using a specially designed photoelectric atomic force microscopy and found to be significantly enhanced at domain walls. Additionally, spatially resolved photoconductive current distribution reveals a higher density of excited carriers at domain walls in comparison with domains. Our measurements demonstrate that domain wall enhanced photovoltaic current originates from its high conduction rather than the internal electric field. This photoconduction facilitated local photovoltaic current is likely to be a universal property of topological defects in ferroelectric semiconductors.

Photovoltaic cell module and method of forming

DOEpatents

Howell, Malinda; Juen, Donnie; Ketola, Barry; Tomalia, Mary Kay

2017-12-12

A photovoltaic cell module, a photovoltaic array including at least two modules, and a method of forming the module are provided. The module includes a first outermost layer and a photovoltaic cell disposed on the first outermost layer. The module also includes a second outermost layer disposed on the photovoltaic cell and sandwiching the photovoltaic cell between the second outermost layer and the first outermost layer. The method of forming the module includes the steps of disposing the photovoltaic cell on the first outermost layer, disposing a silicone composition on the photovoltaic cell, and compressing the first outermost layer, the photovoltaic cell, and the second layer to form the photovoltaic cell module.

Photovoltaic power generation system free of bypass diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lentine, Anthony L.; Okandan, Murat; Nielson, Gregory N.

A photovoltaic power generation system that includes a solar panel that is free of bypass diodes is described herein. The solar panel includes a plurality of photovoltaic sub-modules, wherein at least two of photovoltaic sub-modules in the plurality of photovoltaic sub-modules are electrically connected in parallel. A photovoltaic sub-module includes a plurality of groups of electrically connected photovoltaic cells, wherein at least two of the groups are electrically connected in series. A photovoltaic group includes a plurality of strings of photovoltaic cells, wherein a string of photovoltaic cells comprises a plurality of photovoltaic cells electrically connected in series. The stringsmore » of photovoltaic cells are electrically connected in parallel, and the photovoltaic cells are microsystem-enabled photovoltaic cells.« less

Exploring Near-Field Radiative Heat Transfer for Thermo-photovoltaic Applications

NASA Astrophysics Data System (ADS)

Ganjeh, Yashar; Song, Bai; Sadat, Seid; Thompson, Dakotah; Fiorino, Anthony; Reddy, Pramod; Meyhofer, Edgar

2014-03-01

Understanding near-field radiative heat transfer (NFRHT) is critical for developing efficient thermo-photovoltaic devices. Theoretical predictions suggest that when the spatial separation of two parallel planes at different temperatures is less than their Wien's thermal wavelength, thermal transport via radiation can be greatly enhanced. The radiative heat flow across nanoscale gaps is predicted to be orders-of-magnitude higher than that given by Stefan-Boltzmann law, due to contribution of evanescent waves. In order to test these predictions, a novel experimental platform was designed and built enabling parallelization of two planar surfaces (50 μm by 50 μm) with 500 microradian resolution in their relative orientation. This platform was used to probe NFRHT between two planes and also between a plane and a sphere. It was found that, when a 50 μm diameter silica sphere was approximately 20 nm away from a 50 by 50 μm2 silica plane, a significant increase in radiative heat transfer coefficient was observed. This increase is 3 orders of magnitude higher than the value predicted by the blackbody limit. Other setups, including Au spheres and planes, and the plane-plane geometries are currently being investigated. 1) Army Research office (W911NF-12-1-0612), 2) NSF Thermal Transport Prcesses (CBET 1235691), 3) Center for Solar and Thermal Energy conversion, funded by the US Department of Energy, Office of Science, Basic Energy Sciences under award no. DE-SC0000957.

Photovoltaics in the Department of Defense

NASA Astrophysics Data System (ADS)

Chapman, Richard N.

1997-02-01

This paper documents the history of photovoltaic use within the Department of Defense leading up to the installation of 2.1 MW of photovoltaics underway today. This history describes the evolution of the Department of Defense's Tri-Service Photovoltaic Review Committee and the committee's strategic plan to realize photovoltaic's full potential through outreach, conditioning of the federal procurement system, and specific project development. The Photovoltaic Review Committee estimates photovoltaic's potential at nearly 4,000 MW, of which about 700 MW are considered to be cost-effective at today's prices. The paper describes photovoltaic's potential within the Department of Defense, the status and features of the 2.1-MW worth of photovoltaic systems under installation, and how these systems are selected and implemented. The paper also documents support provided to the Department of Defense by the Department of Energy dating back to the late 70s.

Physical aspects of ferroelectric semiconductors for photovoltaic solar energy conversion

NASA Astrophysics Data System (ADS)

Lopez-Varo, Pilar; Bertoluzzi, Luca; Bisquert, Juan; Alexe, Marin; Coll, Mariona; Huang, Jinsong; Jimenez-Tejada, Juan Antonio; Kirchartz, Thomas; Nechache, Riad; Rosei, Federico; Yuan, Yongbo

2016-10-01

Solar energy conversion using semiconductors to fabricate photovoltaic devices relies on efficient light absorption, charge separation of electron-hole pair carriers or excitons, and fast transport and charge extraction to counter recombination processes. Ferroelectric materials are able to host a permanent electrical polarization which provides control over electrical field distribution in bulk and interfacial regions. In this review, we provide a critical overview of the physical principles and mechanisms of solar energy conversion using ferroelectric semiconductors and contact layers, as well as the main achievements reported so far. In a ferroelectric semiconductor film with ideal contacts, the polarization charge would be totally screened by the metal layers and no charge collection field would exist. However, real materials show a depolarization field, smooth termination of polarization, and interfacial energy barriers that do provide the control of interface and bulk electric field by switchable spontaneous polarization. We explore different phenomena as the polarization-modulated Schottky-like barriers at metal/ferroelectric interfaces, depolarization fields, vacancy migration, and the switchable rectifying behavior of ferroelectric thin films. Using a basic physical model of a solar cell, our analysis provides a general picture of the influence of ferroelectric effects on the actual power conversion efficiency of the solar cell device, and we are able to assess whether these effects or their combinations are beneficial or counterproductive. We describe in detail the bulk photovoltaic effect and the contact layers that modify the built-in field and the charge injection and separation in bulk heterojunction organic cells as well as in photocatalytic and water splitting devices. We also review the dominant families of ferroelectric materials that have been most extensively investigated and have provided the best photovoltaic performance.

US photovoltaic patents: 1991-1993

NASA Astrophysics Data System (ADS)

Pohle, L.

1995-03-01

This document contains US patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials as well as manufacturing and support functions. The patent entries in this document were issued from 1991 to 1993. The entries were located by searching USPA, the database of the US Patent Office. The final search retrieved all patents under the class 'Batteries, Thermoelectric and Photoelectric' and the subclasses 'Photoelectric,' 'Testing,' and 'Applications.' The search also located patents that contained the words 'photovoltaic(s)' or 'solar cell(s)' and their derivatives. After the initial list was compiled, most of the patents on the following subjects were excluded: space photovoltaic technology, use of the photovoltaic effect for detectors, and subjects only peripherally concerned with photovoltaic. Some patents on these three subjects were included when ft appeared that those inventions might be of use in terrestrial PV power technologies.

You're a What? Solar Photovoltaic Installer

ERIC Educational Resources Information Center

Torpey, Elka Maria

2009-01-01

This article talks about solar photovoltaic (PV) installer and features Rebekah Hren, a solar PV installer who puts solar panels on roofs and in other sunny places to turn the sun's power into electricity. Hren enjoys promoting renewable energy, in part because it's an emerging field. In solar PV systems, solar cells--devices that convert sunlight…

Thin film photovoltaic panel and method

DOEpatents

Ackerman, Bruce; Albright, Scot P.; Jordan, John F.

1991-06-11

A thin film photovoltaic panel includes a backcap for protecting the active components of the photovoltaic cells from adverse environmental elements. A spacing between the backcap and a top electrode layer is preferably filled with a desiccant to further reduce water vapor contamination of the environment surrounding the photovoltaic cells. The contamination of the spacing between the backcap and the cells may be further reduced by passing a selected gas through the spacing subsequent to sealing the backcap to the base of the photovoltaic panels, and once purged this spacing may be filled with an inert gas. The techniques of the present invention are preferably applied to thin film photovoltaic panels each formed from a plurality of photovoltaic cells arranged on a vitreous substrate. The stability of photovoltaic conversion efficiency remains relatively high during the life of the photovoltaic panel, and the cost of manufacturing highly efficient panels with such improved stability is significantly reduced.

US photovoltaic patents: 1991--1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pohle, L

1995-03-01

This document contains US patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials as well as manufacturing and support functions. The patent entries in this document were issued from 1991 to 1993. The entries were located by searching USPA, the database of the US Patent Office. The final search retrieved all patents under the class ``Batteries, Thermoelectric and Photoelectric`` and the subclasses ``Photoelectric,`` ``Testing,`` and ``Applications.`` The search also located patents that contained the words ``photovoltaic(s)`` or ``solar cell(s)`` and their derivatives. After the initial list was compiled, most of the patents on the following subjects weremore » excluded: space photovoltaic technology, use of the photovoltaic effect for detectors, and subjects only peripherally concerned with photovoltaic. Some patents on these three subjects were included when ft appeared that those inventions might be of use in terrestrial PV power technologies.« less

Design and field performance of the KENETECH photovoltaic inverter system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behnke, M.R.

1995-11-01

KENETECH Windpower has recently adapted the power conversion technology developed for the company`s variable speed wind turbine to grid-connected photovoltaic applications. KENETECH PV inverter systems are now in successful operation at the Sacramento Municipal Utility District`s (SMUD) Hedge Substation and the PVUSA-Davis site, with additional systems scheduled to be placed into service by the end of 1995 at SMUD, the New York Power Authority, Xerox Corporation`s Clean Air Now project, and the Georgia Tech Aquatic Center. The features of the inverter are described.

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…

Microscopic Perspective on Photovoltaic Reciprocity in Ultrathin Solar Cells

NASA Astrophysics Data System (ADS)

Aeberhard, Urs; Rau, Uwe

2017-06-01

The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions. Its derivation is based on detailed balance relations between local absorption and emission rates in optically isotropic media with nondegenerate quasiequilibrium carrier distributions. In many cases, the dependence of density and spatial variation of electronic and optical device states on the point of operation is modest and the reciprocity relation holds. In nanostructure-based photovoltaic devices exploiting confined modes, however, the underlying assumptions are no longer justifiable. In the case of ultrathin absorber solar cells, the modification of the electronic structure with applied bias is significant due to the large variation of the built-in field. Straightforward use of the external quantum efficiency as measured at short circuit conditions in the photovoltaic reciprocity theory thus fails to reproduce the electroluminescence spectrum at large forward bias voltage. This failure is demonstrated here by numerical simulation of both spectral quantities at normal incidence and emission for an ultrathin GaAs p -i -n solar cell using an advanced quantum kinetic formalism based on nonequilibrium Green's functions of coupled photons and charge carriers. While coinciding with the semiclassical relations under the conditions of their validity, the theory provides a consistent microscopic relationship between absorption, emission, and charge carrier transport in photovoltaic devices at arbitrary operating conditions and for any shape of optical and electronic density of states.

Microscopic Perspective on Photovoltaic Reciprocity in Ultrathin Solar Cells.

PubMed

Aeberhard, Urs; Rau, Uwe

2017-06-16

The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions. Its derivation is based on detailed balance relations between local absorption and emission rates in optically isotropic media with nondegenerate quasiequilibrium carrier distributions. In many cases, the dependence of density and spatial variation of electronic and optical device states on the point of operation is modest and the reciprocity relation holds. In nanostructure-based photovoltaic devices exploiting confined modes, however, the underlying assumptions are no longer justifiable. In the case of ultrathin absorber solar cells, the modification of the electronic structure with applied bias is significant due to the large variation of the built-in field. Straightforward use of the external quantum efficiency as measured at short circuit conditions in the photovoltaic reciprocity theory thus fails to reproduce the electroluminescence spectrum at large forward bias voltage. This failure is demonstrated here by numerical simulation of both spectral quantities at normal incidence and emission for an ultrathin GaAs p-i-n solar cell using an advanced quantum kinetic formalism based on nonequilibrium Green's functions of coupled photons and charge carriers. While coinciding with the semiclassical relations under the conditions of their validity, the theory provides a consistent microscopic relationship between absorption, emission, and charge carrier transport in photovoltaic devices at arbitrary operating conditions and for any shape of optical and electronic density of states.

Field trial of rural solar photovoltaic system

NASA Astrophysics Data System (ADS)

Basu, P.; Mukhopadhyay, K.; Banerjee, T.; Das, S.; Saha, H.

Experience, costs, and performance of photovoltaic (PV) systems set up in a remote Indian village to power an adult literacy center and an irrigation pump are described. The center was furnished with a 14-module, 200 W array to power a television and three fluorescent lamps. The pumping installation has 20 modules for a 300 W output directly coupled to a 300-W dc pump motor. Data were gathered on the open circuit voltage, short circuit current, specific gravity of the battery fluid, degradation of the cells, nominal operating temperature of the cells, load currents, Amp-hours, water flow rate (pump), and the static head and draw down rate (pump). Monitoring of the array performances in the dusty environment showed that once/week cleaning is necessary. Al-substrates cracked at the center installation and sealant evaporation caused condensation which degraded the light transmissivity and thereby the short-circuit current of the modules. The combination of low-efficiency (5 pct) cells and cheap labor demonstrated economic operation without high-efficiency cells.

Measurement of Global Radiation using Photovoltaic Panels

NASA Astrophysics Data System (ADS)

Veroustraete, Frank; Bronders, Jan; Lefevre, Filip; Mensink, Clemens

2014-05-01

The Vito Unit - Environmental and Spatial Aspects (RMA) - for many of its models makes use of global solar radiation. From this viewpoint and also from the notion that this variable is seldom measured or available at the local scale and at high multi-temporal frequencies, it can be stated that many models are fed with low quality estimates of global solar radiation at the local to regional scales. A project was initiated called SUNSPIDER with the following objective. To make use of photovoltaic solar panels to measure solar radiation at the highest spatio-temporal resolution, from the local to the regional scales and from minutes to years. To integrate the measured solar fields in different application fields like, plant systems and agriculture, agro-meteorology and hydrology and last but not least solar energy applications. In Belgium about 250.000 PV installations have been built leading to about 6% electric power supply from photovoltaics on a yearly basis. Last year in June, the supply reached a peak of more than 20% of the total power input on the Belgian grid. A database of Belgian residential solar panel sites will be compiled. The database will serve as an input to an inverted PV model to be able to perform radiation calculations specifically for each of the validated panel sites based on minutely logged power data. Data acquisition for these sites will start each time a site is validated and hence imported in the database. Keywords: Photovoltaic Panels; PV modelling; Global Radiation.

High-concentration planar microtracking photovoltaic system exceeding 30% efficiency

NASA Astrophysics Data System (ADS)

Price, Jared S.; Grede, Alex J.; Wang, Baomin; Lipski, Michael V.; Fisher, Brent; Lee, Kyu-Tae; He, Junwen; Brulo, Gregory S.; Ma, Xiaokun; Burroughs, Scott; Rahn, Christopher D.; Nuzzo, Ralph G.; Rogers, John A.; Giebink, Noel C.

2017-08-01

Prospects for concentrating photovoltaic (CPV) power are growing as the market increasingly values high power conversion efficiency to leverage now-dominant balance of system and soft costs. This trend is particularly acute for rooftop photovoltaic power, where delivering the high efficiency of traditional CPV in the form factor of a standard rooftop photovoltaic panel could be transformative. Here, we demonstrate a fully automated planar microtracking CPV system <2 cm thick that operates at fixed tilt with a microscale triple-junction solar cell at >660× concentration ratio over a 140∘ full field of view. In outdoor testing over the course of two sunny days, the system operates automatically from sunrise to sunset, outperforming a 17%-efficient commercial silicon solar cell by generating >50% more energy per unit area per day in a direct head-to-head competition. These results support the technical feasibility of planar microtracking CPV to deliver a step change in the efficiency of rooftop solar panels at a commercially relevant concentration ratio.

Energy conversion approaches and materials for high-efficiency photovoltaics.

PubMed

Green, Martin A; Bremner, Stephen P

2016-12-20

The past five years have seen significant cost reductions in photovoltaics and a correspondingly strong increase in uptake, with photovoltaics now positioned to provide one of the lowest-cost options for future electricity generation. What is becoming clear as the industry develops is that area-related costs, such as costs of encapsulation and field-installation, are increasingly important components of the total costs of photovoltaic electricity generation, with this trend expected to continue. Improved energy-conversion efficiency directly reduces such costs, with increased manufacturing volume likely to drive down the additional costs associated with implementing higher efficiencies. This suggests the industry will evolve beyond the standard single-junction solar cells that currently dominate commercial production, where energy-conversion efficiencies are fundamentally constrained by Shockley-Queisser limits to practical values below 30%. This Review assesses the overall prospects for a range of approaches that can potentially exceed these limits, based on ultimate efficiency prospects, material requirements and developmental outlook.

Effects of early environmental enrichment upon open-field behavior and timidity in the domestic chick.

PubMed

Jones, R B

1982-03-01

Early environmental enrichment was evaluated by its effect on the behavior of 7-day-old male and female domestic chicks in an open field or novel environment and in a hole-in-the-wall test of timidity. The chicks were housed in same-sex groups of 10. The bare environments contained wood litter, food, and water, whereas the enriched boxes also contained various objects. In the open field, immobility was lower while feeding, walking, jumping and vocalization were higher in the enriched birds than in those reared in the bare environment. Enrichment also decreased emergence latencies in the hole-in-the-wall box. The increased stimulation provided by environmental enrichment may decrease fearfulness in subsequent fear-inducing situations and may enhance the ability of animals to adapt to novelty.

Next-generation organic photovoltaics based on non-fullerene acceptors

NASA Astrophysics Data System (ADS)

Cheng, Pei; Li, Gang; Zhan, Xiaowei; Yang, Yang

2018-03-01

Over the past three years, a particularly exciting and active area of research within the field of organic photovoltaics has been the use of non-fullerene acceptors (NFAs). Compared with fullerene acceptors, NFAs possess significant advantages including tunability of bandgaps, energy levels, planarity and crystallinity. To date, NFA solar cells have not only achieved impressive power conversion efficiencies of 13-14%, but have also shown excellent stability compared with traditional fullerene acceptor solar cells. This Review highlights recent progress on single-junction and tandem NFA solar cells and research directions to achieve even higher efficiencies of 15-20% using NFA-based organic photovoltaics are also proposed.

Photovoltaic fabrics

DTIC Science & Technology

2015-04-22

CLADDING SOLAR CELLS PV (PHOTOVOLTAIC) University of Massachusetts – Dartmouth 285 Old Westport Road Dartmouth, MA 02747...Lowell, MA 01852 14. ABSTRACT This report describes a project to improve photovoltaic fabrics. It had four objectives: 1) Efficiency – make PV wires on...direct sunlight (AM1.5). Over the duration of the project we demonstrated PV efficiency ranging from 5.04% (wire on a black background) to >8

Enabling reliability assessments of pre-commercial perovskite photovoltaics with lessons learned from industrial standards

NASA Astrophysics Data System (ADS)

Snaith, Henry J.; Hacke, Peter

2018-06-01

Photovoltaic modules are expected to operate in the field for more than 25 years, so reliability assessment is critical for the commercialization of new photovoltaic technologies. In early development stages, understanding and addressing the device degradation mechanisms are the priorities. However, any technology targeting large-scale deployment must eventually pass industry-standard qualification tests and undergo reliability testing to validate the module lifetime. In this Perspective, we review the methodologies used to assess the reliability of established photovoltaics technologies and to develop standardized qualification tests. We present the stress factors and stress levels for degradation mechanisms currently identified in pre-commercial perovskite devices, along with engineering concepts for mitigation of those degradation modes. Recommendations for complete and transparent reporting of stability tests are given, to facilitate future inter-laboratory comparisons and to further the understanding of field-relevant degradation mechanisms, which will benefit the development of accelerated stress tests.

Natural conditions and administrative settings for concentrating photovoltaics in China

NASA Astrophysics Data System (ADS)

Fu, Ling; Chen, Xiaoyuan; Leutz, Ralf

2012-10-01

It is an inevitable trend for China to develop green technologies to help the country to produce cleaner energy and to consume it more efficiently, under the pressure of energy security concern, the nation's emissions trajectory and sustainable economic development. The abundant solar resources in West China provide a big potential to utilize the solar energy. Under the promotion of key incentive policies including both feed-in-tariff (FIT) mechanisms and government rebate programs, China has become a major global solar force in photovoltaic (PV) industry both in manufacturing and in the installation of flat-plate products, with 16 GW production and 2.75 GW installation achieved in the year 2011. As a branch of PV technology, concentrating photovoltaics (CPV) technology with several years' development history in China is presently moving from pilot facilities to commercial-scale applications. Several MW-CPV power plants have been installed by both domestic and western companies in China, factories with several hundred-MW production capacity are being planned or built. Sustainable performance and reliability improvement of CPV modules, a vertical integration of supply chain in CPV industry aiming at a cost reduction, a sufficient grid infrastructure for facilitating the West-East and North-South electricity transmission will promote Chinese CPV market to actually initiate, develop and mature.

A photovoltaic industry overview - The results of a survey on photovoltaic technology industrialization

NASA Technical Reports Server (NTRS)

Ferber, R. R.; Costogue, E. N.; Thornhill, J. W.; Shimada, K.

1981-01-01

The National Photovoltaics Program of the United States Department of Energy has the objective of bringing photovoltaic power systems to a point where they can supply a significant portion of the United States energy requirements by the year 2000. This is planned to be accomplished through substantial research and technology development activities aimed at achieving major cost reductions and market penetration. This paper presents information derived from a limited survey performed to obtain photovoltaic industry attitudes concerning industrialization, and to determine current industry plans to meet the DOE program goals. Silicon material production, a key photovoltaic manufacturing industry, is highlighted with regards to implementation of technology improvement and silicon material supply outlook.

Enhancement of Local Photovoltaic Current at Ferroelectric Domain Walls in BiFeO3

PubMed Central

Yang, Ming-Min; Bhatnagar, Akash; Luo, Zheng-Dong; Alexe, Marin

2017-01-01

Domain walls, which are intrinsically two dimensional nano-objects exhibiting nontrivial electronic and magnetic behaviours, have been proven to play a crucial role in photovoltaic properties of ferroelectrics. Despite this recognition, the electronic properties of domain walls under illumination until now have been accessible only to macroscopic studies and their effects upon the conduction of photovoltaic current still remain elusive. The lack of understanding hinders the developing of nanoscale devices based on ferroelectric domain walls. Here, we directly characterize the local photovoltaic and photoconductive properties of 71° domain walls on BiFeO3 thin films with a nanoscale resolution. Local photovoltaic current, proven to be driven by the bulk photovoltaic effect, has been probed over the whole illuminated surface by using a specially designed photoelectric atomic force microscopy and found to be significantly enhanced at domain walls. Additionally, spatially resolved photoconductive current distribution reveals a higher density of excited carriers at domain walls in comparison with domains. Our measurements demonstrate that domain wall enhanced photovoltaic current originates from its high conduction rather than the internal electric field. This photoconduction facilitated local photovoltaic current is likely to be a universal property of topological defects in ferroelectric semiconductors. PMID:28216672

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)

Microsystems Enabled Photovoltaics

ScienceCinema

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

2018-06-07

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.

Photovoltaic tests and applications project

NASA Technical Reports Server (NTRS)

1978-01-01

The activities and accomplishments of the Photovoltaic Tests and Applications Project during the period April 1976 through June 1977 are summarized. Results of efforts to identify potential near-term photovoltaic applications and users are discussed, including the outcome of an extensive survey of Federal government agencies. The status of application experiments is presented. Various general engineering efforts are reported, including the design and construction of a photovoltaic Systems Test Facility. Efforts to develop a high efficiency 10 kVA self-commutated inverter and controller specifically designed for photovoltaic systems are also discussed. The results of a wide variety of activities in the area of photovoltaic measurements and standards are related. Documents generated by the Project during the reporting period are listed in an Appendix.

TVA's photovoltaic activities

NASA Astrophysics Data System (ADS)

Chinery, G. T.; Wood, J. M.

1985-08-01

This paper describes the Tennessee Valley Authority's (TVA) current photovoltaic (PV) activities. These include four roof-mounted 4 kWp residential arrays (which are also Southeast Residential Station field sites) and two 5-6 kWp commercial sites, all grid connected with no battery storage. Also included are approximately 30 kWp of non-grid-connected remote sites with storage (remote lighting, weather stations, etc.). Monitoring results from the two 'online' residential systems are presented. Finally, TVA's future PV plans are discussed, both with respect to interfacing with a multitude of residential and commercial cogenerators and with regard to possible TVA PV central station plans.

Enlarging photovoltaic effect: combination of classic photoelectric and ferroelectric photovoltaic effects

PubMed Central

Zhang, Jingjiao; Su, Xiaodong; Shen, Mingrong; Dai, Zhihua; Zhang, Lingjun; He, Xiyun; Cheng, Wenxiu; Cao, Mengyu; Zou, Guifu

2013-01-01

Converting light energy to electrical energy in photovoltaic devices relies on the photogenerated electrons and holes separated by the built-in potential in semiconductors. Photo-excited electrons in metal electrodes are usually not considered in this process. Here, we report an enhanced photovoltaic effect in the ferroelectric lanthanum-modified lead zirconate titanate (PLZT) by using low work function metals as the electrodes. We believe that electrons in the metal with low work function could be photo-emitted into PLZT and form the dominant photocurrent in our devices. Under AM1.5 (100 mW/cm2) illumination, the short-circuit current and open-circuit voltage of Mg/PLZT/ITO are about 150 and 2 times of those of Pt/PLZT/ITO, respectively. The photovoltaic response of PLZT capacitor was expanded from ultraviolet to visible spectra, and it may have important impact on design and fabrication of high performance photovoltaic devices based on ferroelectric materials. PMID:23811832

Enlarging photovoltaic effect: combination of classic photoelectric and ferroelectric photovoltaic effects.

PubMed

Zhang, Jingjiao; Su, Xiaodong; Shen, Mingrong; Dai, Zhihua; Zhang, Lingjun; He, Xiyun; Cheng, Wenxiu; Cao, Mengyu; Zou, Guifu

2013-01-01

Converting light energy to electrical energy in photovoltaic devices relies on the photogenerated electrons and holes separated by the built-in potential in semiconductors. Photo-excited electrons in metal electrodes are usually not considered in this process. Here, we report an enhanced photovoltaic effect in the ferroelectric lanthanum-modified lead zirconate titanate (PLZT) by using low work function metals as the electrodes. We believe that electrons in the metal with low work function could be photo-emitted into PLZT and form the dominant photocurrent in our devices. Under AM1.5 (100 mW/cm²) illumination, the short-circuit current and open-circuit voltage of Mg/PLZT/ITO are about 150 and 2 times of those of Pt/PLZT/ITO, respectively. The photovoltaic response of PLZT capacitor was expanded from ultraviolet to visible spectra, and it may have important impact on design and fabrication of high performance photovoltaic devices based on ferroelectric materials.

Solar photovoltaics for development applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shepperd, L.W.; Richards, E.H.

1993-08-01

This document introduces photovoltaic technology to individuals and groups specializing in development activities. Examples of actual installations illustrate the many services supplied by photovoltaic systems in development applications, including water pumping, lighting, health care, refrigeration, communications, and a variety of productive uses. The various aspects of the technology are explored to help potential users evaluate whether photovoltaics can assist them in achieving their organizational goals. Basic system design, financing techniques, and the importance of infrastructure are included, along with additional sources of information and major US photovoltaic system suppliers.

Publications | Photovoltaic Research | NREL

Science.gov Websites

Publications Publications The scientists in the National Center for Photovoltaics (NCPV) at NREL publish a variety of documents related to photovoltaic and related research, including journal articles

Combined effects of space charge and energetic disorder on photocurrent efficiency loss of field-dependent organic photovoltaic devices

NASA Astrophysics Data System (ADS)

Yoon, Sangcheol; Park, Byoungchoo; Hwang, Inchan

2015-11-01

The loss of photocurrent efficiency by space-charge effects in organic solar cells with energetic disorder was investigated to account for how energetic disorder incorporates space-charge effects, utilizing a drift-diffusion model with field-dependent charge-pair dissociation and suppressed bimolecular recombination. Energetic disorder, which induces the Poole-Frenkel behavior of charge carrier mobility, is known to decrease the mobility of charge carriers and thus reduces photovoltaic performance. We found that even if the mobilities are the same in the absence of space-charge effects, the degree of energetic disorder can be an additional parameter affecting photocurrent efficiency when space-charge effects occur. Introducing the field-dependence parameter that reflects the energetic disorder, the behavior of efficiency loss with energetic disorder can differ depending on which charge carrier is subject to energetic disorder. While the energetic disorder that is applied to higher-mobility charge carriers decreases photocurrent efficiency further, the efficiency loss can be suppressed when energetic disorder is applied to lower-mobility charge carriers.

Photovoltaic test and demonstration project for the National Photovoltaic Conversion program

NASA Technical Reports Server (NTRS)

Deyo, J. N.

1975-01-01

Proposed are photovoltaic system tests and demonstrations covering a wide range of applications in order to develop low cost photovoltaic cells suitable for terrestrial applications. Program objectives are: (1) tests and model system demonstrations; (2) device performance and diagnostics; and (3) endurance of solar cell modules and arrays.

Advancing colloidal quantum dot photovoltaic technology

NASA Astrophysics Data System (ADS)

Cheng, Yan; Arinze, Ebuka S.; Palmquist, Nathan; Thon, Susanna M.

2016-06-01

Colloidal quantum dots (CQDs) are attractive materials for solar cells due to their low cost, ease of fabrication and spectral tunability. Progress in CQD photovoltaic technology over the past decade has resulted in power conversion efficiencies approaching 10%. In this review, we give an overview of this progress, and discuss limiting mechanisms and paths for future improvement in CQD solar cell technology.We briefly summarize nanoparticle synthesis and film processing methods and evaluate the optoelectronic properties of CQD films, including the crucial role that surface ligands play in materials performance. We give an overview of device architecture engineering in CQD solar cells. The compromise between carrier extraction and photon absorption in CQD photovoltaics is analyzed along with different strategies for overcoming this trade-off. We then focus on recent advances in absorption enhancement through innovative device design and the use of nanophotonics. Several light-trapping schemes, which have resulted in large increases in cell photocurrent, are described in detail. In particular, integrating plasmonic elements into CQD devices has emerged as a promising approach to enhance photon absorption through both near-field coupling and far-field scattering effects. We also discuss strategies for overcoming the single junction efficiency limits in CQD solar cells, including tandem architectures, multiple exciton generation and hybrid materials schemes. Finally, we offer a perspective on future directions for the field and the most promising paths for achieving higher device efficiencies.

Determination of optimum mounting configurations for flat-plate photovoltaic modules based on a structured field experiment and simulated results from PVFORM, a photovoltaic system performance model

NASA Astrophysics Data System (ADS)

Menicucci, D. F.

1986-01-01

The performance of a photovoltaic (PV) system is affected by its mounting configuration. The optimal configuration is unclear because of lack of experience and data. Sandia National Laboratories, Albuquerque (SNLA), has conducted a controlled field experiment to compare four types of the most common module mounting. The data from the experiment were used to verify the accuracy of PVFORM, a new computer program that simulates PV performance. PVFORM was then used to simulate the performance of identical PV modules on different mounting configurations at 10 sites throughout the US. This report describes the module mounting configurations, the experimental methods used, the specialized statistical techniques used in the analysis, and the final results of the effort. The module mounting configurations are rank ordered at each site according to their annual and seasonal energy production performance, and each is briefly discussed in terms of its advantages and disadvantages in various applications.

Chapter 3: Photovoltaic Module Stability and Reliability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, Dirk; Kurtz, Sarah

2017-01-01

Profits realized from investment in photovoltaic will benefit from decades of reliable operation. Service life prediction through accelerated tests is only possible if indoor tests duplicate power loss and failure modes observed in fielded systems. Therefore, detailing and quantifying power loss and failure modes is imperative. In the first section, we examine recent trends in degradation rates, the gradual power loss observed for different technologies, climates and other significant factors. In the second section, we provide a summary of the most commonly observed failure modes in fielded systems.

Description of photovoltaic village power systems in the United States and Africa

NASA Technical Reports Server (NTRS)

Ratajczak, A. F.; Bifano, W. J.

1979-01-01

Photovoltaic power systems in remote villages in the United States and Africa are described. These projects were undertaken to demonstrate that existing photovoltaic system technology is capable of providing electrical power for basic domestic services for the millions of small, remote communities in both developed and developing countries. One system is located in the Papago Indian Village of Schuchuli in southwest Arizona (U. S.) and became operational 16 December 1978. The other system is located in Tangaye, a rural village in Upper Volta, Africa. It became operational 1 March 1979. The Schuchuli system has a 3.5 kW (peak) solar array which provides electric power for village water pumping, a refrigerator for each family, lights in the village buildings, and a community washing machine and sewing machine. The 1.8 kW (peak) Tangaye system provides power for community water pumping, flour milling and lights in the milling building. These are both stand-alone systems (i.e., no back-up power source) which are being operated and maintained by local personnel. Both systems are instrumented. Systems operations are being monitored by NASA to measure design adequacy and to refine designs for future systems.

US photovoltaic patents, 1951--1987

NASA Astrophysics Data System (ADS)

1988-09-01

This document contains 2195 U.S. patents on terrestrial photovoltaic (PV) power applications, including systems, components, and materials as well as manufacturing and support functions. The patent entries in this document were issued from 1951 through 1987; no patents were found in 1950. The entries were located by searching USPA, the data base of the U.S. Patent Office. The final search retrieved all patents under the class Batteries, Thermoelectric and Photoelectric, and the subclasses Photoelectric, Testing, and Applications. The search also located patents that contained the words photovoltaic(s) or solar cell(s) and their derivatives. A manual search of the patents in the Solar Energy Research Institute (SERI) patent file augmented the data base search. After the initial list was compiled, most of the patents on the following subjects were excluded: space photovoltaic technology, use of the photovoltaic effect for detectors, and subjects only peripherally concerned with photovoltaics. Some patents on these three subjects were included when it appeared that those inventions might be of use in terrwstrial PV power technologies.

Transparent contacts for stacked compound photovoltaic cells

DOEpatents

Tauke-Pedretti, Anna; Cederberg, Jeffrey; Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis

2016-11-29

A microsystems-enabled multi-junction photovoltaic (MEM-PV) cell includes a first photovoltaic cell having a first junction, the first photovoltaic cell including a first semiconductor material employed to form the first junction, the first semiconductor material having a first bandgap. The MEM-PV cell also includes a second photovoltaic cell comprising a second junction. The second photovoltaic cell comprises a second semiconductor material employed to form the second junction, the second semiconductor material having a second bandgap that is less than the first bandgap, the second photovoltaic cell further comprising a first contact layer disposed between the first junction of the first photovoltaic cell and the second junction of the second photovoltaic cell, the first contact layer composed of a third semiconductor material having a third bandgap, the third bandgap being greater than or equal to the first bandgap.

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.

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.

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.

Photovoltaic properties of ferroelectric BaTiO3 thin films RF sputter deposited on silicon

NASA Technical Reports Server (NTRS)

Dharmadhikari, V. S.; Grannemann, W. W.

1982-01-01

Ferroelectric thin films of BaTiO3 have been successfully deposited on n-type silicon substrates at temperatures above 500 C by RF sputtering in an O2/Ar atmosphere. Analysis by X-ray diffraction patterns show that films deposited at room temperature are amorphous. At temperatures above 500 C, crystalline BaTiO3 films with a tetragonal structure are obtained. The polarization-electric field (P-E) hysteresis loops and a broad peak in the dielectric constant versus temperature curve at Curie point indicate that the RF sputtered BaTiO3 films are ferroelectric. An anomalous photovoltaic effect is observed in these thin films which is related to the remanent polarization of the material. The results on open-circuit and short-circuit measurements provide an important basis for a better understanding of the role of photovoltaic field, photovoltaic current, and the pyroelectric properties in photoferroelectric domain switching.

Comparative PV LCOE Calculator Documentation | Photovoltaic Research | NREL

Science.gov Websites

Comparative Photovoltaic (PV) Levelized Cost of Energy (LCOE) Calculator. Getting started This tool is and watch the LCOE values in the results section change immediately. Example: Cell cost reduction In the proposed section, drag the cell cost slider or type in the cell cost numeric input field to reduce

Materials for Photovoltaic Applications

NASA Astrophysics Data System (ADS)

Dimova-Malinovska, Doriana

Energy priorities are changing nowadays. As mankind will probably have to face energy crisis, factors such as energy independence, energy security, stability of energy supply and the variety of energy sources become much more vital these days. Photovoltaics is exceptional compared to other renewable sources of energy due to its wide opportunity to gain energetic and environmental benefits. An overview of the present state of knowledge of the materials aspects of photovoltaic cells will be given, and new semiconductor materials, including nanomaterials, with potential for application in photovoltaic devices will be identified.

Task 2 Report - A GIS-Based Technical Potential Assessment of Domestic Energy Resources for Electricity Generation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Nathan; Grue, Nicholas W; Rosenlieb, Evan

The purpose of this report is to support the Lao Ministry of Energy and Mines in assessing the technical potential of domestic energy resources for utility scale electricity generation in the Lao PDR. Specifically, this work provides assessments of technical potential, and associated maps of developable areas, for energy technologies of interest. This report details the methodology, assumptions, and datasets employed in this analysis to provide a transparent, replicable process for future analyses. The methodology and results presented are intended to be a fundamental input to subsequent decision making and energy planning-related analyses. This work concentrates on domestic energy resourcesmore » for utility-scale electricity generation and considers solar photovoltaic, wind, biomass, and coal resources. This work does not consider potentially imported energy resources (e.g., natural gas) or domestic energy resources that are not present in sufficient quantity for utility-scale generation (e.g., geothermal resources). A technical potential assessment of hydropower resources is currently not feasible due to the absence of required data including site-level assessments of multiple characteristics (e.g., geology environment and access) as well as spatial data on estimated non-exploited hydropower resources. This report is the second output of the Energy Alternatives Study for the Lao PDR, a collaboration led by the Lao Ministry of Energy and Mines and the United States Agency for International Development under the auspices of the Smart Infrastructure for the Mekong program. The Energy Alternatives Study is composed of five successive tasks that collectively support the project's goals. This work is focused on Task 2 - Assess technical potential of domestic energy resources for electricity generation. The work was carried out by a team from the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in collaboration with the Lao Ministry of Energy

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.

Parametric study of laser photovoltaic energy converters

NASA Technical Reports Server (NTRS)

Walker, G. H.; Heinbockel, J. H.

1987-01-01

Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

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

Performance of 350kW concentrating photovoltaic power system after two years

NASA Astrophysics Data System (ADS)

Khoshaim, B.; Huraib, F.; Al-Sani, A.; Salim, A.

This paper summarizes the continuing performance of the world's largest concentrating Photovoltaic Power System (PVPS) which began supplying electrical power to the three remote villages in Saudi Arabia in September 1981. The paper reviews the system performance to date and concentrates mainly on the performance of the most important part of the PVPS that is the photovoltaic array field. Problems and failures experienced with the system so far are reviewed and analyzed. Also, a brief history of the project including its design features is given in this paper.

Reticulated Organic Photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiros T.; Yager K.; Mannsfeld S.

2012-03-21

This paper shows how the self-assembled interlocking of two nanostructured materials can lead to increased photovoltaic performance. A detailed picture of the reticulated 6-DBTTC/C{sub 60} organic photovoltaic (OPV) heterojunction, which produces devices approaching the theoretical maximum for these materials, is presented from near edge X-ray absorption spectroscopy (NEXAFS), X-ray photoelectron spectroscopy (XPS), Grazing Incidence X-ray diffraction (GIXD) and transmission electron microscopy (TEM). The complementary suite of techniques shows how self-assembly can be exploited to engineer the interface and morphology between the cables of donor (6-DBTTC) material and a polycrystalline acceptor (C{sub 60}) to create an interpenetrating network of pure phasesmore » expected to be optimal for OPV device design. Moreover, we find that there is also a structural and electronic interaction between the two materials at the molecular interface. The data show how molecular self-assembly can facilitate 3-D nanostructured photovoltaic cells that are made with the simplicity and control of bilayer device fabrication. The significant improvement in photovoltaic performance of the reticulated heterojunction over the flat analog highlights the potential of these strategies to improve the efficiency of organic solar cells.« less

Natural Flow Air Cooled Photovoltaics

NASA Astrophysics Data System (ADS)

Tanagnostopoulos, Y.; Themelis, P.

2010-01-01

Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. We performed experiments using a prototype based on three silicon photovoltaic modules placed in series to simulate a typical sloping building roof with photovoltaic installation. In this system the air flows through a channel on the rear side of PV panels. The potential for increasing the heat exchange from the photovoltaic panel to the circulating air by the addition of a thin metal sheet (TMS) in the middle of air channel or metal fins (FIN) along the air duct was examined. The operation of the device was studied with the air duct closed tightly to avoid air circulation (CLOSED) and the air duct open (REF), with the thin metal sheet (TMS) and with metal fins (FIN). In each case the experiments were performed under sunlight and the operating parameters of the experimental device determining the electrical and thermal performance of the system were observed and recorded during a whole day and for several days. We collected the data and form PV panels from the comparative diagrams of the experimental results regarding the temperature of solar cells, the electrical efficiency of the installation, the temperature of the back wall of the air duct and the temperature difference in the entrance and exit of the air duct. The comparative results from the measurements determine the improvement in electrical performance of the photovoltaic cells because of the reduction of their temperature, which is achieved by the naturally circulating air.

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.

Photovoltaic Systems Test Facilities: Existing capabilities compilation

NASA Technical Reports Server (NTRS)

Volkmer, K.

1982-01-01

A general description of photovoltaic systems test facilities (PV-STFs) operated under the U.S. Department of Energy's photovoltaics program is given. Descriptions of a number of privately operated facilities having test capabilities appropriate to photovoltaic hardware development are given. A summary of specific, representative test capabilities at the system and subsystem level is presented for each listed facility. The range of system and subsystem test capabilities available to serve the needs of both the photovoltaics program and the private sector photovoltaics industry is given.

Degradation Analysis of Field-Exposed Photovoltaic Modules with Non-Fluoropolymer-Based Backsheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kempe, Michael D; Fairbrother, Andrew; Julien, Scott

The selection of polymeric materials utilized in photovoltaic (PV) modules has changed relatively little since the inception of the PV industry, with ethylene-vinyl acetate (EVA), polyethylene terephthalate (PET), and fluoropolymer-based laminates being the most widely adopted primary components of the encapsulant and backsheet materials. The backsheet must serve to electrically insulate the solar cells and protect them from the effects of weathering. Due to continued downward pressure on cost, other polymeric materials are being formulated to withstand outdoor exposure for use in backsheets to replace either the PET film, the fluoropoymer film, or both. Because of their relatively recent deployment,more » less is known about their reliability and if they are durable enough to fulfill the greater than or equal to 25 year warranties of current PV modules. This work presents a degradation analysis of field-exposed modules with polyamide- and polyester-based backsheets. Modules were exposed for up to five years in different geographic locations: USA (Maryland, Ohio), China, and Italy. Surface and cross-sectional analysis included visual inspection, colorimetry, glossimetry, and Fourier-transform infrared spectroscopy. Each module experienced different types of degradation depending on the exposure site, even for the same material and module brand. For instance, the polyamide-based backsheet experienced hairline cracking and greater yellowing and chemical changes in China (Changsu, humid subtropical climate), while in Italy (Rome, hot-summer Mediterranean climate) it underwent macroscopic cracking and greater losses in gloss. Spectroscopic studies have permitted identification of degradation products and changes in polymer structure over time. Comparisons are made to fielded modules with fluoropolymer-based backsheets, as well as backsheet materials in accelerated laboratory exposures. Implications for qualification testing and service life prediction of the non

Degradation analysis of field-exposed photovoltaic modules with non-fluoropolymer-based backsheets

NASA Astrophysics Data System (ADS)

Fairbrother, Andrew; Julien, Scott; Wan, Kai-Tak; Ji, Liang; Boyce, Kenneth; Merzlic, Sebastien; Lefebvre, Amy; O'Brien, Greg; Wang, Yu; Bruckman, Laura; French, Roger; Kempe, Michael; Gu, Xiaohong

2017-08-01

The selection of polymeric materials utilized in photovoltaic (PV) modules has changed relatively little since the inception of the PV industry, with ethylene-vinyl acetate (EVA), polyethylene terephthalate (PET), and fluoropolymer-based laminates being the most widely adopted primary components of the encapsulant and backsheet materials. The backsheet must serve to electrically insulate the solar cells and protect them from the effects of weathering. Due to continued downward pressure on cost, other polymeric materials are being formulated to withstand outdoor exposure for use in backsheets to replace either the PET film, the fluoropoymer film, or both. Because of their relatively recent deployment, less is known about their reliability and if they are durable enough to fulfill the >=25 year warranties of current PV modules. This work presents a degradation analysis of field-exposed modules with polyamide- and polyester-based backsheets. Modules were exposed for up to five years in different geographic locations: USA (Maryland, Ohio), China, and Italy. Surface and cross-sectional analysis included visual inspection, colorimetry, glossimetry, and Fourier-transform infrared spectroscopy. Each module experienced different types of degradation depending on the exposure site, even for the same material and module brand. For instance, the polyamide-based backsheet experienced hairline cracking and greater yellowing and chemical changes in China (Changsu, humid subtropical climate), while in Italy (Rome, hot-summer Mediterranean climate) it underwent macroscopic cracking and greater losses in gloss. Spectroscopic studies have permitted identification of degradation products and changes in polymer structure over time. Comparisons are made to fielded modules with fluoropolymer-based backsheets, as well as backsheet materials in accelerated laboratory exposures. Implications for qualification testing and service life prediction of the non-fluoropolymer-based backsheets are

Domestic Violence during Pregnancy in an Eastern City of Turkey: A Field Study

ERIC Educational Resources Information Center

Arslantas, Hulya; Adana, Filiz; Ergin, Filiz; Gey, Neriman; Bicer, Nejla; Kiransal, Nilufer

2012-01-01

Violence is an increasing and important community health problem that can be seen in any area of human life. Limited studies were found about domestic violence among pregnant women and its relation with social status of women. The aim of this study was to determine the prevalence and types of domestic violence during pregnancy, factors affecting…

Solar photovoltaic reflective trough collection structure

DOEpatents

Anderson, Benjamin J.; Sweatt, William C.; Okandan, Murat; Nielson, Gregory N.

2015-11-19

A photovoltaic (PV) solar concentration structure having at least two troughs encapsulated in a rectangular parallelepiped optical plastic structure, with the troughs filled with an optical plastic material, the troughs each having a reflective internal surface and approximately parabolic geometry, and the troughs each including photovoltaic cells situated so that light impinging on the optical plastic material will be concentrated onto the photovoltaic cells. Multiple structures can be connected to provide a solar photovoltaic collection system that provides portable, efficient, low-cost electrical power.

Acetylene-Based Materials in Organic Photovoltaics

PubMed Central

Silvestri, Fabio; Marrocchi, Assunta

2010-01-01

Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (poly)arylacetylenes that have been used in the field. A general introduction to (poly)arylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (co)polymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C60, and their use as the active materials in photovoltaic devices. PMID:20480031

Photovoltaic Power Station with Ultracapacitors for Storage

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.; Kolacz, John S.; Soltis, Richard F.; Tavernelli, Paul F.

2003-01-01

A solar photovoltaic power station in which ultracapacitors, rather than batteries, are used to store energy is discussed. Developments in the semiconductor industry have reduced the cost and increased the attainable efficiency of commercially available photovoltaic panels; as a result, photovoltaic generation of power for diverse applications has become practical. Photovoltaic generation can provide electric power in remote locations where electric power would otherwise not be available. Photovoltaic generation can also afford independence from utility systems. Applications include supplying power to scientific instruments and medical equipment in isolated geographical regions.

PV Reliability Workshop | Photovoltaic Research | NREL

Science.gov Websites

Laboratory. NREL hosts an annual Photovoltaic Reliability Workshop (PVRW) so that solar technology experts Photovoltaic Reliability Workshop (PVRW) will be held Tuesday, February 27, to Thursday, March 1, at the workshop. 2017 Workshop The 2017 Photovoltaic Reliability Workshop (PVRW) was Tuesday, February 28, to

DOE Forms National Center for Photovoltaics

Science.gov Websites

, Georgia, Florida and New Mexico. The alliance also will include the Utility Photovoltaic Group, a testing in partnership with the U.S. photovoltaic industry. For industry that means one-stop shopping for amorphous silicon and cadmium telluride photovoltaic modules, and manufacturing of silicon sheet and

Solar photovoltaic systems

NASA Technical Reports Server (NTRS)

Forney, R. G.

1978-01-01

The Department of Energy's photovoltaic program is outlined. The main objective of the program is the development of low cost reliable terrestrial photovoltaic systems. A second objective is to foster widespread use of the system in residential, industrial and commercial application. The system is reviewed by examining each component; silicon solar cell, silicon solar cell modules, advanced development modules and power systems. Cost and applications of the system are discussed.

U.S. Department of Energy Photovoltaic Energy Program Contract Summary: Fiscal Year 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Surek, T.

2001-02-21

This report summarizes the in-house and subcontracted research and development (R and D) activities under the National Center for Photovoltaics (NCPV) and U.S. Department of Energy (DOE) National Photovoltaics Program from October 1, 1999, through September 30, 2000 (FY 2000). The mission of the DOE National Photovoltaics Program is to make PV a significant part of the domestic economy-as an industry and an energy resource. The two primary goals of the national program are to (1) maintain the U.S. industry's world leadership in research and technology development and (2) help the U.S. industry remain a major, profitable force in themore » world market. The NCPV is part of the National PV Program and provides leadership and support to the national program toward achieving its mission and goals. This Contract Summary for fiscal year (FY) 2000 documents some 179 research projects supported by the PV Program, performed by 107 organizations in 32 states, including 69 projects performed by universities and 60 projects performed by our industry partners. Of the total FY 2000 PV Program budget of $65.9 million, the industry and university research efforts received $36.9 million, or nearly 56%. And, of this amount, more than 93% was for contractors selected on a competitive basis. Much of the funding to industry was matched by industry cost-sharing. Each individual effort described in this summary represents another step toward improving PV manufacturing, performance, cost, and applications, and another step toward accomplishing the DOE PV Program's overall mission.« less

Trypanosomiasis in domestic livestock in the Lambwe Valley area and a field evaluation of various diagnostic techniques

PubMed Central

Robson, J.; Ashkar, T. S.

1972-01-01

A preliminary survey of 2 073 domestic animals in the Lambwe Valley, Kenya, showed a 7.4% rate of infection with Trypanosoma congolense and T. vivax. In comprehensive surveys covering 6 384 domestic stock, pathogenic trypanosomes were found in 17.0% of cattle, 5.0% of sheep, and 2.1% of goats. Adults were more often infected than young animals, and males more often than females. T. congolense was the trypanosome most frequently diagnosed, followed by T. vivax and the T. brucei subgroup. T. theileri was also found. The examination of wet blood films in the field as a means of diagnosing trypanosome infections was shown to be valueless. More infections were detected in peripheral blood films than in systemic blood films, but both should be examined. An examination of smears of glandular fluid is essential for the diagnosis of T. vivax in cattle, while mouse-inoculation tests are necessary for the diagnosis of the T. brucei subgroup. The detection of T. vivax was improved by the high-speed centrifugation of blood samples in capillary tubes. PMID:4544823

Interplay of Nanoscale, Hybrid P3HT/ZTO Interface on Optoelectronics and Photovoltaic Cells.

PubMed

Lai, Jian-Jhong; Li, Yu-Hsun; Feng, Bo-Rui; Tang, Shiow-Jing; Jian, Wen-Bin; Fu, Chuan-Min; Chen, Jiun-Tai; Wang, Xu; Lee, Pooi See

2017-09-27

Photovoltaic effects in poly(3-hexylthiophene-2,5-diyl) (P3HT) have attracted much attention recently. Here, natively p-type doped P3HT nanofibers and n-type doped zinc tin oxide (ZTO) nanowires are used for making not only field-effect transistors (FETs) but also p-n nanoscale diodes. The hybrid P3HT/ZTO p-n heterojunction shows applications in many directions, and it also facilitates the investigation of photoelectrons and photovoltaic effects on the nanoscale. As for applications, the heterojunction device shows a simultaneously high on/off ratio of n- and p-type FETs, gatable p-n junction diodes, tristate buffer devices, gatable photodetectors, and gatable solar cells. On the other hand, P3HT nanofibers are taken as a photoactive layer and the role played by the p-n heterojunction in the photoelectric and photovoltaic effects is investigated. It is found that the hybrid P3HT/ZTO p-n heterojunction assists in increasing photocurrents and enhancing photovoltaic effects. Through the controllable gating of the heterojunction, we can discuss the background mechanisms of photocurrent generation and photovoltaic energy harvesting.

Low-frequency switching voltage regulators for terrestrial photovoltaic systems

NASA Technical Reports Server (NTRS)

Delombard, R.

1984-01-01

The photovoltaic technology project and the stand alone applications project are discussed. Two types of low frequency switching type regulators were investigated. The design, operating characteristics and field application of these regulators is described. The regulators are small in size, low in cost, very low in power dissipation, reliable and allow considerable flexibility in system design.

16th Space Photovoltaic Research and Technology Conference. Revised

NASA Technical Reports Server (NTRS)

Bailey, Sheila (Editor)

2005-01-01

The purpose of the SPRAT conference is to bring members of the space solar cell community together in a relatively informal conference setting to discuss the recent developments in solar cell technology and to discuss the future directions of the field. The conference is sponsored by the Photovoltaic and Space Environmental Effects Branch at the NASA Glenn Research Center.

Photovoltaic restoration of sight in rodents with retinal degeneration (Conference Presentation)

NASA Astrophysics Data System (ADS)

Palanker, Daniel V.

2017-02-01

To restore vision in patients who lost their photoreceptors due to retinal degeneration, we developed a photovoltaic subretinal prosthesis which converts light into pulsed electric current, stimulating the nearby inner retinal neurons. Visual information is projected onto the retina by video goggles using pulsed near-infrared ( 900nm) light. This design avoids the use of bulky electronics and wiring, thereby greatly reducing the surgical complexity. Optical activation of the photovoltaic pixels allows scaling the implants to thousands of electrodes, and multiple modules can be tiled under the retina to expand the visual field. We found that similarly to normal vision, retinal response to prosthetic stimulation exhibits flicker fusion at high frequencies (>20Hz), adaptation to static images, and non-linear summation of subunits in the receptive fields. Photovoltaic arrays with 70um pixels restored visual acuity up to a single pixel pitch, which is only two times lower than natural acuity in rats. If these results translate to human retina, such implants could restore visual acuity up to 20/250. With eye scanning and perceptual learning, human patients might even cross the 20/200 threshold of legal blindness. In collaboration with Pixium Vision, we are preparing this system (PRIMA) for a clinical trial. To further improve visual acuity, we are developing smaller pixels - down to 40um, and on 3-D interface to improve proximity to the target neurons. Scalability, ease of implantation and tiling of these wireless modules to cover a large visual field, combined with high resolution opens the door to highly functional restoration of sight.

DOE LeRC photovoltaic systems test facility

NASA Technical Reports Server (NTRS)

Cull, R. C.; Forestieri, A. F.

1978-01-01

The facility was designed and built and is being operated as a national facility to serve the needs of the entire DOE National Photovoltaic Program. The object of the facility is to provide a place where photovoltaic systems may be assembled and electrically configured, without specific physical configuration, for operation and testing to evaluate their performance and characteristics. The facility as a breadboard system allows investigation of operational characteristics and checkout of components, subsystems and systems before they are mounted in field experiments or demonstrations. The facility as currently configured consist of 10 kW of solar arrays built from modules, two inverter test stations, a battery storage system, interface with local load and the utility grid, and instrumentation and control necessary to make a flexible operating facility. Expansion to 30 kW is planned for 1978. Test results and operating experience are summaried to show the variety of work that can be done with this facility.

International market assessment of stand-alone photovoltaic power systems for cottage industry applications

NASA Astrophysics Data System (ADS)

Philippi, T. M.

1981-11-01

The final result of an international assessment of the market for stand-alone photovoltaic systems in cottage industry applications is reported. Nonindustrialized countries without centrally planned economies were considered. Cottage industries were defined as small rural manufacturers, employing less than 50 people, producing consumer and simple products. The data to support this analysis were obtained from secondary and expert sources in the U.S. and in-country field investigations of the Philippines and Mexico. The near-term market for photovoltaics for rural cottage industry applications appears to be limited to demonstration projects and pilot programs, based on an in-depth study of the nature of cottage industry, its role in the rural economy, the electric energy requirements of cottage industry, and a financial analysis of stand-alone photovoltaic systems as compared to their most viable competitor, diesel driven generators. Photovoltaics are shown to be a better long-term option only for very low power requirements. Some of these uses would include clay mixers, grinders, centrifuges, lathes, power saws and lighting of a workshop.

International market assessment of stand-alone photovoltaic power systems for cottage industry applications

NASA Technical Reports Server (NTRS)

Philippi, T. M.

1981-01-01

The final result of an international assessment of the market for stand-alone photovoltaic systems in cottage industry applications is reported. Nonindustrialized countries without centrally planned economies were considered. Cottage industries were defined as small rural manufacturers, employing less than 50 people, producing consumer and simple products. The data to support this analysis were obtained from secondary and expert sources in the U.S. and in-country field investigations of the Philippines and Mexico. The near-term market for photovoltaics for rural cottage industry applications appears to be limited to demonstration projects and pilot programs, based on an in-depth study of the nature of cottage industry, its role in the rural economy, the electric energy requirements of cottage industry, and a financial analysis of stand-alone photovoltaic systems as compared to their most viable competitor, diesel driven generators. Photovoltaics are shown to be a better long-term option only for very low power requirements. Some of these uses would include clay mixers, grinders, centrifuges, lathes, power saws and lighting of a workshop.

Photovoltaics | Climate Neutral Research Campuses | NREL

Science.gov Websites

Photovoltaics Photovoltaics Solar photovoltaics (PV) is a mature, commercially available technology arrays. Campus Solar Energy Options A PV system requires periodic maintenance, but upkeep averages two to undertaking a solar energy assessment or PV installation. Solar Energy Resources Solar energy production

Photovoltaics: Current status and future projections

NASA Astrophysics Data System (ADS)

Dorn, D. W.

1981-10-01

The generation of electricity by photovoltaic means was examined. Projections of near future developments are made, together with estimates of their impact on the cost and availability of photovoltaic systems for various markets. This concluded that photovoltaic systems should be able to deliver electricity at a cost of between 5 to 10 cents per kilowatt hour by 1986.

Method for Prediction of the Power Output from Photovoltaic Power Plant under Actual Operating Conditions

NASA Astrophysics Data System (ADS)

Obukhov, S. G.; Plotnikov, I. A.; Surzhikova, O. A.; Savkin, K. D.

2017-04-01

Solar photovoltaic technology is one of the most rapidly growing renewable sources of electricity that has practical application in various fields of human activity due to its high availability, huge potential and environmental compatibility. The original simulation model of the photovoltaic power plant has been developed to simulate and investigate the plant operating modes under actual operating conditions. The proposed model considers the impact of the external climatic factors on the solar panel energy characteristics that improves accuracy in the power output prediction. The data obtained through the photovoltaic power plant operation simulation enable a well-reasoned choice of the required capacity for storage devices and determination of the rational algorithms to control the energy complex.

Domestic Violence

MedlinePlus

f AQ FREQUENTLY ASKED QUESTIONS FAQ083 WOMEN’S HEALTH Domestic Violence • What is domestic violence? • What are the types of abuse? • How can ... are available to help abused women? What is domestic violence? Domestic violence is a pattern of threatening or ...

Photovoltaic cell with thin CS layer

DOEpatents

Jordan, John F.; Albright, Scot P.

1994-01-18

An improved photovoltaic panel and method of forming a photovoltaic panel are disclosed for producing a high efficiency CdS/CdTe photovoltaic cell. The photovoltaic panel of the present invention is initially formed with a substantially thick Cds layer, and the effective thickness of the CdS layer is substantially reduced during regrowth to both form larger diameter CdTe crystals and substantially reduce the effective thickness of the C This invention was made with Government support under Subcontract No. ZL-7-06031-3 awarded by the Department of Energy. The Government has certain rights in this invention.

Graphite-based photovoltaic cells

DOEpatents

Lagally, Max; Liu, Feng

2010-12-28

The present invention uses lithographically patterned graphite stacks as the basic building elements of an efficient and economical photovoltaic cell. The basic design of the graphite-based photovoltaic cells includes a plurality of spatially separated graphite stacks, each comprising a plurality of vertically stacked, semiconducting graphene sheets (carbon nanoribbons) bridging electrically conductive contacts.

48 CFR 252.225-7018 - Photovoltaic Devices-Certificate.

Code of Federal Regulations, 2014 CFR

2014-10-01

... that such photovoltaic device (e.g., solar panel) is a designated country photovoltaic device shall be... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Photovoltaic Devices... of Provisions And Clauses 252.225-7018 Photovoltaic Devices—Certificate. As prescribed in 225.7017-4...

48 CFR 252.225-7018 - Photovoltaic Devices-Certificate.

Code of Federal Regulations, 2013 CFR

2013-10-01

... that such photovoltaic device (e.g., solar panel) is a designated country photovoltaic device shall be... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Photovoltaic Devices... of Provisions And Clauses 252.225-7018 Photovoltaic Devices—Certificate. As prescribed in 225.7017-4...

In-field measurements of PCDD/F emissions from domestic heating appliances for solid fuels.

PubMed

Hübner, C; Boos, R; Prey, T

2005-01-01

Within this project the emissions into the atmosphere of polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) of 30 domestic heating appliances in Austrian households were tested. The appliances were single stoves (kitchen stove, continuous burning stove and tiled stove) and central heating boilers for solid fuels up to a nominal heat input of 50 kW. A main objective of this survey was to determine the PCDD/F emissions of domestic heating units under routine conditions. Therefore, the habitual combustion conditions used by the operators were not influenced. The original fuels and lightning supports were used and the operation of the units was carried out by the householders according to their usual practice. The data obtained were used to calculate in-field PCDD/F-emission factors. Most of the appliances have shown PCDD/F emissions within a concentration range of 0.01-0.3 ng TEQ/MJ. Modern fan-assisted wood heating boilers with afterburning and units for continuously burning of wood chips and wood pellets had the lowest emissions. High emissions were caused by unsuitable heating habits such as combustion of wastes and inappropriate operation of the appliances. There were only small differences between single stoves and central heating boilers or between wood and coal-fired appliances. The emission factors calculated are higher than those cited in literature, which are mainly derived from trials on test stands under laboratory conditions.

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.

Photovoltaic system criteria documents. Volume 4: Review criteria for photovoltaic applications

NASA Technical Reports Server (NTRS)

Koenig, John C.; Billitti, Joseph W.; Tallon, John M.

1979-01-01

Guidelines are provided for the organization, preparation and conduct of program reviews for photovoltaic applications. These criteria apply to all photovoltaic applications. They include, but are not limited to, the following: (1) Conceptual design review; (2) Preliminary design review; (3) Critical design review; and (4) Operational readiness review. Contract goal's and objectives are met through program monitoring for cost, schedule, and performance for both managerial and technical elements for all PV applications activities.

Study on photovoltaic power system on ships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katagi, Takeshi; Fujii, Yoshimi; Nishikawa, Eiichi

1995-11-01

This paper presents the application of photovoltaic power systems to ships. Two types of leisure or fishing boats powered by photovoltaics are designed. The boats described are single hull and catamaran type with twin hulls. The design of a new electric power system using a photovoltaic power system in a harbor ship having 20 tons is also proposed. The results of this study show that the photovoltaic power system can apply to small ships.

Time-asymmetric photovoltaics.

PubMed

Green, Martin A

2012-11-14

Limits upon photovoltaic energy conversion efficiency generally are formulated using the detailed balance approach of Shockley and Queisser. One key underlying assumption is invariance upon time reversal, underpinning detailed balance itself. Recent proposals for compact, layered, time-asymmetrical, magneto-optical devices make their routine implementation likely. It is shown that such time-asymmetry can alter the relationship between solar cell emission and absorption assumed in the Shockley-Queisser approach, allowing generally accepted photovoltaic performance limits to be exceeded.

Photovoltaic Subcontract Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

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)more » 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.« less

Spectrally-engineered solar thermal photovoltaic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lenert, Andrej; Bierman, David; Chan, Walker

A solar thermal photovoltaic device, and method of forming same, includes a solar absorber and a spectrally selective emitter formed on either side of a thermally conductive substrate. The solar absorber is configured to absorb incident solar radiation. The solar absorber and the spectrally selective emitter are configured with an optimized emitter-to-absorber area ratio. The solar thermal photovoltaic device also includes a photovoltaic cell in thermal communication with the spectrally selective emitter. The spectrally selective emitter is configured to permit high emittance for energies above a bandgap of the photovoltaic cell and configured to permit low emittance for energies belowmore » the bandgap.« less

A sensitivity analysis of central flat-plate photovoltaic systems and implications for national photovoltaics program planning

NASA Technical Reports Server (NTRS)

Crosetti, M. R.

1985-01-01

The sensitivity of the National Photovoltaic Research Program goals to changes in individual photovoltaic system parameters is explored. Using the relationship between lifetime cost and system performance parameters, tests were made to see how overall photovoltaic system energy costs are affected by changes in the goals set for module cost and efficiency, system component costs and efficiencies, operation and maintenance costs, and indirect costs. The results are presented in tables and figures for easy reference.

At home in the postcolony: Ecology, empire and domesticity at the Lamto field station, Ivory Coast.

PubMed

Lachenal, Guillaume

2016-12-01

This article is a history of the field station Lamto, in Ivory Coast, which was created by French ecologists in 1962, after independence. It retraces the origins, the logics and the contradictions of an extraordinarily ambitious scientific project, which aimed at the systematic, holistic, quantitative and multi-disciplinary description of a unit of African nature - the savannah ecosystem. It explores how knowledge-making was articulated with work hierarchies and postcolonial politics, lifestyles, values and affects. It reconstitutes the political ecology of a research station in ecology, following in its residences, laboratories and open-air experiments the co-production of domesticity, nature, science and (post-)colonial situations.

Solid domestic wastes as a renewable resource: European experience

NASA Astrophysics Data System (ADS)

Fridland, V. S.; Livshits, I. M.

2011-01-01

Ways in which different types of solid domestic wastes, such as wastepaper, crushed glass, plastics and worn-out tires, can be efficiently included into the production, raw-material, and energy balances of the national economy are shown taking Germany and other European countries an example. Methods for recycling these solid domestic wastes and application fields of the obtained products are discussed.

Home Photovoltaic System Design in Pangkalpinang City

NASA Astrophysics Data System (ADS)

Sunanda, Wahri

2018-02-01

This research aims to obtain the design of home photovoltaic systems in Pangkalpinang and the opportunity of economic savings. The system consists of photovoltaic with batteries. Based on electricity consumption of several houses with installed power of 1300 VA and 2200 VA in Pangkalpinang for one year, the daily load of photovoltaic system is varied to 40%, 30% and 20% of the average value of the daily home electricity consumption. The investment costs, the cost of replacement parts and the cost of electricity consumption accrued to PLN during lifetime of systems (25 years) are also calculated. The result provided that there are no economic saving opportunities for photovoltaic systems with batteries at home with installed power of 1300 VA and 2200 VA in Pangkalpinang. The most economical is the photovoltaic system with the daily load of 20% of the average value of the daily home electricity consumption. The configuration of photovoltaic system for 1300 VA home consists of 10 modules of 200 wattpeak and 4 batteries 150 AH, 12 Volt while photovoltaic system for 2200 VA home consists of 15 modules of 200 wattpeak and 6 batteries 150 AH,12Volt.

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

International photovoltaic products and manufacturers directory, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shepperd, L.W.

1995-11-01

This international directory of more than 500 photovoltaic-related manufacturers is intended to guide potential users of photovoltaics to sources for systems and their components. Two indexes help the user to locate firms and materials. A glossary describes equipment and terminology commonly used in the photovoltaic industry.

Induction soldering of photovoltaic system components

DOEpatents

Kumaria, Shashwat; de Leon, Briccio

2015-11-17

A method comprises positioning a pair of photovoltaic wafers in a side-by-side arrangement. An interconnect is placed on the pair of wafers such that the interconnect overlaps both wafers of the pair, solder material being provided between the interconnect and the respective wafers. A solder head is then located adjacent the interconnect, and the coil is energized to effect inductive heating of the solder material. The solder head comprises an induction coil shaped to define an eye, and a magnetic field concentrator located at least partially in the eye of the coil. The magnetic field concentrator defines a passage extending axially through the eye of the coil, and may be of a material with a high magnetic permeability.

Microinverters for employment in connection with photovoltaic modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lentine, Anthony L.; Nielson, Gregory N.; Okandan, Murat

2015-09-22

Microinverters useable in association with photovoltaic modules are described. A three phase-microinverter receives direct current output generated by a microsystems-enabled photovoltaic cell and converts such direct current output into three-phase alternating current out. The three-phase microinverter is interleaved with other three-phase-microinverters, wherein such microinverters are integrated in a photovoltaic module with the microsystems-enabled photovoltaic cell.

Photovoltaic module with adhesion promoter

DOEpatents

Xavier, Grace

2013-10-08

Photovoltaic modules with adhesion promoters and methods for fabricating photovoltaic modules with adhesion promoters are described. A photovoltaic module includes a solar cell including a first surface and a second surface, the second surface including a plurality of interspaced back-side contacts. A first glass layer is coupled to the first surface by a first encapsulating layer. A second glass layer is coupled to the second surface by a second encapsulating layer. At least a portion of the second encapsulating layer is bonded directly to the plurality of interspaced back-side contacts by an adhesion promoter.

Evidence for oxygen vacancy or ferroelectric polarization induced switchable diode and photovoltaic effects in BiFeO3 based thin films.

PubMed

Guo, Yiping; Guo, Bing; Dong, Wen; Li, Hua; Liu, Hezhou

2013-07-12

The diode and photovoltaic effects of BiFeO3 and Bi0.9Sr0.1FeO(3-δ) polycrystalline thin films were investigated by poling the films with increased magnitude and alternating direction. It was found that both electromigration of oxygen vacancies and polarization flipping are able to induce switchable diode and photovoltaic effects. For the Bi0.9Sr0.1FeO(3-δ) thin films with high oxygen vacancy concentration, reversibly switchable diode and photovoltaic effects can be observed due to the electromigration of oxygen vacancies under an electric field much lower than its coercive field. However, for the pure BiFeO3 thin films with lower oxygen vacancy concentration, the reversibly switchable diode and photovoltaic effect is hard to detect until the occurrence of polarization flipping. The switchable diode and photovoltaic effects can be explained well using the concepts of Schottky-like barrier-to-Ohmic contacts resulting from the combination of oxygen vacancies and polarization. The sign of photocurrent could be independent of the direction of polarization when the modulation of the energy band induced by oxygen vacancies is large enough to offset that induced by polarization. The photovoltaic effect induced by the electromigration of oxygen vacancies is unstable due to the diffusion of oxygen vacancies or the recombination of oxygen vacancies with hopping electrons. Our work provides deep insights into the nature of diode and photovoltaic effects in ferroelectric films, and will facilitate the advanced design of switchable devices combining spintronic, electronic, and optical functionalities.

Real options analysis for photovoltaic project under climate uncertainty

NASA Astrophysics Data System (ADS)

Kim, Kyeongseok; Kim, Sejong; Kim, Hyoungkwan

2016-08-01

The decision on photovoltaic project depends on the level of climate environments. Changes in temperature and insolation affect photovoltaic output. It is important for investors to consider future climate conditions for determining investments on photovoltaic projects. We propose a real options-based framework to assess economic feasibility of photovoltaic project under climate change. The framework supports investors to evaluate climate change impact on photovoltaic projects under future climate uncertainty.

Photovoltaic building sheathing element with anti-slide features

DOEpatents

Keenihan, James R.; Langmaid, Joseph A.; Lopez, Leonardo C.

2015-09-08

The present invention is premised` upon an assembly that includes at least a photovoltaic building sheathing element capable of being affixed on a building structure, the photovoltaic building sheathing element. The element including a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly; and at feast a first and a second connector assembly capable of directly or indirectly electrically connecting the photovoltaic cell assembly to one or more adjoining devices; wherein the body portion includes one or more geometric features adapted to engage a vertically adjoining device before installation.

Animal evolution during domestication: the domesticated fox as a model.

PubMed

Trut, Lyudmila; Oskina, Irina; Kharlamova, Anastasiya

2009-03-01

We review the evolution of domestic animals, emphasizing the effect of the earliest steps of domestication on its course. Using the first domesticated species, the dog (Canis familiaris), for illustration, we describe the evolutionary peculiarities during the historical domestication, such as the high level and wide range of diversity. We suggest that the process of earliest domestication via unconscious and later conscious selection of human-defined behavioral traits may accelerate phenotypic variations. The review is based on the results of a long-term experiment designed to reproduce early mammalian domestication in the silver fox (Vulpes vulpes) selected for tameability or amenability to domestication. We describe changes in behavior, morphology and physiology that appeared in the fox during its selection for tameability, which were similar to those observed in the domestic dog. Based on the data of the fox experiment and survey of relevant data, we discuss the developmental, genetic and possible molecular genetic mechanisms underlying these changes. We ascribe the causative role in evolutionary transformation of domestic animals to the selection for behavior and to the neurospecific regulatory genes it affects.

Animal evolution during domestication: the domesticated fox as a model

PubMed Central

Trut, Lyudmila; Oskina, Irina; Kharlamova, Anastasiya

2009-01-01

Summary We review the evolution of domestic animals, emphasizing the effect of the earliest steps of domestication on its course. Using the first domesticated species, the dog (Canis familiaris) as an illustration, we describe the evolutionary specificities of the historical domestication, such as the high level and wide range of diversity. We suggest that the process of earliest domestication via unconscious and later conscious selection of human-defined behavioral traits may accelerate phenotypic variations. The review is based on the results of the long-term experiment designed to reproduce early mammalian domestication in the silver fox (Vulpes vulpes) selected for tameability, or amenability to domestication. We describe changes in behavior, morphology and physiology that appeared in the fox during its selection for tameability and that were similar to those observed in the domestic dog. Based on the experimental fox data and survey of relevant data, we discuss the developmental, genetic and possible molecular-genetic mechanisms of these changes. We assign the causative role in evolutionary transformation of domestic animals to selection for behavior and to the neurospecific regulatory genes it affects. PMID:19260016

In situ KPFM imaging of local photovoltaic characteristics of structured organic photovoltaic devices.

PubMed

Watanabe, Satoshi; Fukuchi, Yasumasa; Fukasawa, Masako; Sassa, Takafumi; Kimoto, Atsushi; Tajima, Yusuke; Uchiyama, Masanobu; Yamashita, Takashi; Matsumoto, Mutsuyoshi; Aoyama, Tetsuya

2014-02-12

Here, we discuss the local photovoltaic characteristics of a structured bulk heterojunction, organic photovoltaic devices fabricated with a liquid carbazole, and a fullerene derivative based on analysis by scanning kelvin probe force microscopy (KPFM). Periodic photopolymerization induced by an interference pattern from two laser beams formed surface relief gratings (SRG) in the structured films. The surface potential distribution in the SRGs indicates the formation of donor and acceptor spatial distribution. Under illumination, the surface potential reversibly changed because of the generation of fullerene anions and hole transport from the films to substrates, which indicates that we successfully imaged the local photovoltaic characteristics of the structured photovoltaic devices. Using atomic force microscopy, we confirmed the formation of the SRG because of the material migration to the photopolymerized region of the films, which was induced by light exposure through photomasks. The structuring technique allows for the direct fabrication and the control of donor and acceptor spatial distribution in organic photonic and electronic devices with minimized material consumption. This in situ KPFM technique is indispensable to the fabrication of nanoscale electron donor and electron acceptor spatial distribution in the devices.

Charge carrier transport and photogeneration in P3HT:PCBM photovoltaic blends.

PubMed

Laquai, Frédéric; Andrienko, Denis; Mauer, Ralf; Blom, Paul W M

2015-06-01

This article reviews the charge transport and photogeneration in bulk-heterojunction solar cells made from blend films of regioregular poly(3-hexylthiophene) (RR-P3HT) and methano-fullerene (PCBM). The charge transport, specifically the hole mobility in the RR-P3HT phase of the polymer:fullerene photovoltaic blend, is dramatically affected by thermal annealing. The hole mobility increases more than three orders of magnitude and reaches a value of up to 2 × 10(-4) cm(2) V(-1) s(-1) after the thermal annealing process as a result of an improved semi-crystallinity of the film. This significant increase of the hole mobility balances the electron and hole mobilities in a photovoltaic blend in turn reducing space-charge formation, and this is the most important factor for the strong enhancement of the photovoltaic efficiency compared to an as cast, that is, non-annealed device. In fact, the balanced charge carrier mobility in RR-P3HT:PCBM blends in combination with a field- and temperature-independent charge carrier generation and greatly reduced non-geminate recombination explains the large quantum efficiencies mea-sured in P3HT:PCBM photovoltaic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimizing Grid Patterns on Photovoltaic Cells

NASA Technical Reports Server (NTRS)

Burger, D. R.

1984-01-01

CELCAL computer program helps in optimizing grid patterns for different photovoltaic cell geometries and metalization processes. Five different powerloss phenomena associated with front-surface metal grid pattern on photovoltaic cells.

Understanding the physical properties of hybrid perovskites for photovoltaic applications

NASA Astrophysics Data System (ADS)

Huang, Jinsong; Yuan, Yongbo; Shao, Yuchuan; Yan, Yanfa

2017-07-01

New photovoltaic materials have been searched for in the past decades for clean and renewable solar energy conversion with an objective of reducing the levelized cost of electricity (that is, the unit price of electricity over the course of the device lifetime). An emerging family of semiconductor materials — organic-inorganic halide perovskites (OIHPs) — are the focus of the photovoltaic research community owing to their use of low cost, nature-abundant raw materials, low-temperature and scalable solution fabrication processes, and, in particular, the very high power conversion efficiencies that have been achieved within the short time of their development. In this Review, we summarize and critically assess the most recent advances in understanding the physical properties of both 3D and low-dimensional OIHPs that favour a small open-circuit voltage deficit and high power conversion efficiency. Several prominent topics in this field on the unique properties of OIHPs are surveyed, including defect physics, ferroelectricity, exciton dissociation processes, carrier recombination lifetime and photon recycling. The impact of ion migration on solar cell efficiency and stability are also critically analysed. Finally, we discuss the remaining challenges in the commercialization of OIHP photovoltaics.

NREL Photovoltaic Program FY 1996 Annual Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report summarizes the in-house and subcontract research and development (R&D) activities under the National Renewable Energy Laboratory (NREL) Photovoltaics (PV) Program from October 1, 1995 through September 30, 1996 (fiscal year [FY] 1996). The NREL PV Program is part of the U.S. Department of Energy's (DOE) National Photovoltaics Program, as described in the DOE Photovoltaics Program Plan, FY 1991 - FY 1995. The mission of the DOE National Photovoltaics Program is to: "Work in partnership with U.S. industry to develop and deploy photovoltaic technology for generating economically competitive electric power, making photovoltaics an important contributor to the nation's andmore » the world's energy use and environmental improvement. The two primary goals of the national program are to (1) maintain the U.S. PV industry's world leadership in research and technology development and (2) help the U.S. industry remain a major, profitable force in the world market. The NREL PV Program provides leadership and support to the national program toward achieving its mission and goals.« less

Mounting support for a photovoltaic module

DOEpatents

Brandt, Gregory Michael; Barsun, Stephan K.; Coleman, Nathaniel T.; Zhou, Yin

2013-03-26

A mounting support for a photovoltaic module is described. The mounting support includes a foundation having an integrated wire-way ledge portion. A photovoltaic module support mechanism is coupled with the foundation.

Lightweight Solar Photovoltaic Blankets

NASA Technical Reports Server (NTRS)

Ceragioli, R.; Himmler, R.; Nath, P.; Vogeli, C.; Guha, S.

1995-01-01

Lightweight, flexible sheets containing arrays of stacked solar photovoltaic cells developed to supply electric power aboard spacecraft. Solar batteries satisfying stringent requirements for operation in outer space also adaptable to terrestrial environment. Attractive for use as long-lived, portable photovoltaic power sources. Cells based on amorphous silicon which offers potential for order-of-magnitude increases in power per unit weight, power per unit volume, and endurance in presence of ionizing radiation.

Photovoltaics program plan, FY 1991 - 1995

NASA Astrophysics Data System (ADS)

1991-10-01

This program plan describes the goals and philosophy of DOE National Photovoltaics Program and its major research and development activities for fiscal years (FY) 1991 through 1995. The plan represents a consensus among researchers and manufacturers, as well as current and potential users of photovoltaics (PV). It defines the activities that we believe are necessary to continue the rapid progress toward acceptance of photovoltaics as a serious candidate for cost-competitive electric power generation by the utility, transportation, buildings, and industrial sectors. A successful National Photovoltaics Program will help achieve many of our national priorities. The mission of the National Photovoltaics Program is to help US industry to develop photovoltaic technology for large-scale generation of economically competitive electric power in the United States, making PV a significant part of our national energy mix. To fully achieve this, we must continue to work toward the long-term goals established in our previous program plan: reducing the price of delivered electricity to 5 to 6 cents per kilowatt-hour (kWh), increasing lifetimes to 30 years, and increasing module efficiencies to 15 percent for flat-plate and 25 percent for concentrator technologies. If progress continues at its current pace, we expect that the PV industry will have installed at least 1000 megawatts (MW) of capacity in the United States and 500 MW internationally by the year 2000.

Progress of genome wide association study in domestic animals

PubMed Central

2012-01-01

Domestic animals are invaluable resources for study of the molecular architecture of complex traits. Although the mapping of quantitative trait loci (QTL) responsible for economically important traits in domestic animals has achieved remarkable results in recent decades, not all of the genetic variation in the complex traits has been captured because of the low density of markers used in QTL mapping studies. The genome wide association study (GWAS), which utilizes high-density single-nucleotide polymorphism (SNP), provides a new way to tackle this issue. Encouraging achievements in dissection of the genetic mechanisms of complex diseases in humans have resulted from the use of GWAS. At present, GWAS has been applied to the field of domestic animal breeding and genetics, and some advances have been made. Many genes or markers that affect economic traits of interest in domestic animals have been identified. In this review, advances in the use of GWAS in domestic animals are described. PMID:22958308

Frequently Asked Questions | Photovoltaic Research | NREL

Science.gov Websites

Principles for Terrestrial Photovoltaic (PV) Solar Devices with Reference Spectral Irradiance Data ERDA/NASA TM 73702: Terrestrial Photovoltaic Measurement Procedures, ERDA / NASA / 1022-77 / 16, June 1977. K.A

Solar photovoltaics: Stand alone applications

NASA Astrophysics Data System (ADS)

Deyo, J. N.

1980-11-01

The Lewis Research Center involvement in space photovoltaic research and development and in using photovoltaics for terrestrial applications is described with emphasis on applications in which the normal source of power may be a diesel generator, batteries, or other types of power not connected to a utility grid. Once an application is processed, technology is developed and demonstrated with a user who participates in the cost and furnishes the site. Projects completed related to instruments, communication, refrigeration, and highways, are described as well as warning systems, weather stations, fire lookouts, and village power systems. A commercially available photovoltaic powered electric fence charger is the result of Lewis research and development.

Highway renewable energy : photovoltaic noise barriers

DOT National Transportation Integrated Search

2017-07-01

Highway photovoltaic noise barriers (PVNBs) represent the combination of noise barrier systems and photovoltaic systems in order to mitigate traffic noise while simultaneously producing renewable energy. First deployed in Switzerland in 1989, PVNBs a...

Design of a Glenn Research Center Solar Field Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) designed, developed, and installed, a 37.5 kW DC photovoltaic (PV) Solar Field in the GRC West Area in the 1970s for the purpose of testing PV panels for various space and terrestrial applications. The PV panels are arranged to provide a nominal 120 VDC. The GRC Solar Field has been extremely successful in meeting its mission. The PV panels and the supporting electrical systems are all near their end of life. GRC has designed a 72 kW DC grid-tied PV power system to replace the existing GRC West Area Solar Field. The 72 kW DC grid-tied PV power system will provide DC solar power for GRC PV testing applications, and provide AC facility power for all times that research power is not required. A grid-tied system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility for use by all. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provide valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. The report concludes that the GRC West Area grid-tied PV power system design is viable for a reliable

Terrestrial Photovoltaic System Analysis.

DTIC Science & Technology

1980-07-01

the photovoltaic arrays was detertttined to be the roof on the building adjacent to the plating facilit.. Sult ficitut roof area is available to...indicated here: Component 50 kW System 300 kW System Solar Array $10/W $"’/W Inverter $38/W $I/W (dlitereut supplier) The life-cycle cost analysis...27 15. Various solar energy concem t rating systems .......... 3 I. Varionts photovoltaic concentrators developed under PRDA- 15

Photovoltaic sub-cell interconnects

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Hest, Marinus Franciscus Antonius Maria; Swinger Platt, Heather Anne

2017-05-09

Photovoltaic sub-cell interconnect systems and methods are provided. In one embodiment, a photovoltaic device comprises a thin film stack of layers deposited upon a substrate, wherein the thin film stack layers are subdivided into a plurality of sub-cells interconnected in series by a plurality of electrical interconnection structures; and wherein the plurality of electrical interconnection structures each comprise no more than two scribes that penetrate into the thin film stack layers.

Methods and analysis of factors impact on the efficiency of the photovoltaic generation

NASA Astrophysics Data System (ADS)

Tianze, Li; Xia, Zhang; Chuan, Jiang; Luan, Hou

2011-02-01

First of all, the thesis elaborates two important breakthroughs which happened In the field of the application of solar energy in the 1950s.The 21st century the development of solar photovoltaic power generation will have the following characteristics: the continued high growth of industrial development, the significantly reducing cost of the solar cell, the large-scale high-tech development of photovoltaic industries, the breakthroughs of the film battery technology, the rapid development of solar PV buildings integration and combined to the grids. The paper makes principles of solar cells the theoretical analysis. On the basis, we study the conversion efficiency of solar cells, find the factors impact on the efficiency of the photovoltaic generation, solve solar cell conversion efficiency of technical problems through the development of new technology, and open up new ways to improve the solar cell conversion efficiency. Finally, the paper connecting with the practice establishes policies and legislation to the use of encourage renewable energy, development strategy, basic applied research etc.

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.

Photovoltaic devices having nanoparticle dipoles for enhanced performance and methods for making same

DOEpatents

Williams, George M [Portland, OR; Schut, David M [Philomath, OR; Stonas, Andreas [Albany, OR

2011-08-09

A photovoltaic device has nanoparticles sandwiched between a conductive substrate and a charge selective transport layer. Each of the nanoparticles has a ligand shell attached to the nanoparticle core. A first type of ligand is electron rich and attached to one hemisphere of the nanoparticle core, while a second type of ligand is electron poor and attached to an opposite hemisphere of the core. Consequently, the ligand shell induces an electric field within the nanoparticle, enhancing the photovoltaic effect. The arrangement of ligands types on different sides of the nanoparticle is obtained by a process involving ligand substitution after adhering the nanoparticles to the conductive substrate.

Adolescent-to-Parent Abuse as a Form of "Domestic Violence": A Conceptual Review.

PubMed

Holt, Amanda

2016-12-01

Across the Global North, adolescent-to-parent abuse (APA) is becoming recognized as a significant social problem and is receiving attention from researchers, policymakers, and practitioners who work in the intersecting fields of juvenile justice, child protection, and domestic violence. One of the key questions shaping current debates concerns the extent to which APA maps onto the contours of domestic violence, in terms of research and theory, policy, and practice. In particular, to what extent can our established ways of working with domestic violence be applied when working with APA? This article begins by reviewing definitions and prevalence rates of APA. It then considers how the problem fits into the "family conflicts" and "gender-based violence" paradigms that are most frequently used to conceptualize domestic violence. The article then examines how APA represents a similar but distinct phenomenon to adult-instigated domestic violence and identifies how its departures represent particular challenges in working toward its elimination. The article concludes by reviewing intervention programs that work with APA and exploring some of the ways in which they adopt and reject elements of good practice from the domestic violence practice field. © The Author(s) 2015.

Socioeconomic impact of photovoltaic power at Schuchuli, Arizona

NASA Technical Reports Server (NTRS)

Bahr, D.; Garrett, B. G.; Chrisman, C.

1980-01-01

The social and economic impact of photovoltaic power on a small, remote native American village is studied. Village history, group life, energy use in general, and the use of photovoltaic-powered appliances are discussed. No significant impacts due to the photovoltaic power system were observed.

Fiber-based architectures for organic photovoltaics

NASA Astrophysics Data System (ADS)

Liu, Jiwen; Namboothiry, Manoj A. G.; Carroll, David L.

2007-02-01

Using poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 bulk-heterojunction blends as the absorbing material, organic photovoltaic devices have been fabricated onto multimode optical fibers. The behavior of the short circuit current density, filling factor, and open circuit voltage as the angle of the incident light onto the cleaved fiber face is varied suggests that the evanescent field at the interface between the fiber and the transparent contact may play a role in coupling light from the fiber into the device. Further, optical loss into the device increases as the fiber diameter decreases.

Charge separation and carrier dynamics in donor-acceptor heterojunction photovoltaic systems

PubMed Central

Teuscher, Joël; Brauer, Jan C.; Stepanov, Andrey; Solano, Alicia; Boziki, Ariadni; Chergui, Majed; Wolf, Jean-Pierre; Rothlisberger, Ursula; Banerji, Natalie; Moser, Jacques-E.

2017-01-01

Electron transfer and subsequent charge separation across donor-acceptor heterojunctions remain the most important areas of study in the field of third-generation photovoltaics. In this context, it is particularly important to unravel the dynamics of individual ultrafast processes (such as photoinduced electron transfer, carrier trapping and association, and energy transfer and relaxation), which prevail in materials and at their interfaces. In the frame of the National Center of Competence in Research “Molecular Ultrafast Science and Technology,” a research instrument of the Swiss National Science Foundation, several groups active in the field of ultrafast science in Switzerland have applied a number of complementary experimental techniques and computational simulation tools to scrutinize these critical photophysical phenomena. Structural, electronic, and transport properties of the materials and the detailed mechanisms of photoinduced charge separation in dye-sensitized solar cells, conjugated polymer- and small molecule-based organic photovoltaics, and high-efficiency lead halide perovskite solar energy converters have been scrutinized. Results yielded more than thirty research articles, an overview of which is provided here. PMID:29308415

Charge separation and carrier dynamics in donor-acceptor heterojunction photovoltaic systems.

PubMed

Teuscher, Joël; Brauer, Jan C; Stepanov, Andrey; Solano, Alicia; Boziki, Ariadni; Chergui, Majed; Wolf, Jean-Pierre; Rothlisberger, Ursula; Banerji, Natalie; Moser, Jacques-E

2017-11-01

Electron transfer and subsequent charge separation across donor-acceptor heterojunctions remain the most important areas of study in the field of third-generation photovoltaics. In this context, it is particularly important to unravel the dynamics of individual ultrafast processes (such as photoinduced electron transfer, carrier trapping and association, and energy transfer and relaxation), which prevail in materials and at their interfaces. In the frame of the National Center of Competence in Research "Molecular Ultrafast Science and Technology," a research instrument of the Swiss National Science Foundation, several groups active in the field of ultrafast science in Switzerland have applied a number of complementary experimental techniques and computational simulation tools to scrutinize these critical photophysical phenomena. Structural, electronic, and transport properties of the materials and the detailed mechanisms of photoinduced charge separation in dye-sensitized solar cells, conjugated polymer- and small molecule-based organic photovoltaics, and high-efficiency lead halide perovskite solar energy converters have been scrutinized. Results yielded more than thirty research articles, an overview of which is provided here.

Photovoltaic utility/customer interface study

NASA Astrophysics Data System (ADS)

Eichler, C. H.; Hayes, T. P.; Matthews, M. M.; Wilraker, V. F.

1980-12-01

The technical, economic, and legal and regulatory issues of interconnecting small, privately-owned, on-site photovoltaic generating systems to an electric utility are addressed. Baseline residential, commercial and industrial class photovoltaic systems were developed. Technical issues of concern affecting this interconnection were identified and included fault protection, undervoltage protection, lamp flicker, revenue metering, loss of synchromism, electrical safety, prevention of backfeeding a de-energized utility feeder, effects of on-site generation on utility relaying schemes, effects of power conditioner harmonic distortion on the electric utility, system isolation, electromagnetic interference and site power factor as seen by the utility. Typical interconnection wiring diagrams were developed for interconnecting each class of baseline photovoltaic generating system.

Solar Photovoltaic Manufacturing Cost Analysis | Energy Analysis | NREL

Science.gov Websites

Solar Photovoltaic Manufacturing Cost Analysis Solar Photovoltaic Manufacturing Cost Analysis NREL's photovoltaic (PV) manufacturing cost analysis-part of our broader effort supporting manufacturing manufacturing sector, and is that growth sustainable? NREL's manufacturing cost analysis studies show that: U.S

Photovoltaic Reliability Group activities in USA and Brazil (Presentation Recording)

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.; Cruz, Leila R. O.

2015-09-01

Recently prices of photovoltaic (PV) systems have been reduced considerably and may continue to be reduced making them attractive. If these systems provide electricity over the stipulated warranty period, it would be possible attain socket parity within the next few years. Current photovoltaic module qualifications tests help in minimizing infant mortality but do not guarantee useful lifetime over the warranty period. The PV Module Quality Assurance Task Force (PVQAT) is trying to formulate accelerated tests that will be useful towards achieving the ultimate goal of assuring useful lifetime over the warranty period as well as to assure manufacturing quality. Unfortunately, assuring the manufacturing quality may require 24/7 presence. Alternatively, collecting data on the performance of fielded systems would assist in assuring manufacturing quality. Here PV systems installed by home-owners and small businesses can constitute as an important untapped source of data. The volunteer group, PV - Reliable, Safe and Sustainable Quality! (PVRessQ!) is providing valuable service to small PV system owners. Photovoltaic Reliability Group (PVRG) is initiating activities in USA and Brazil to assist home owners and small businesses in monitoring photovoltaic (PV) module performance and enforcing warranty. It will work in collaboration with small PV system owners, consumer protection agencies. Brazil is endowed with excellent solar irradiance making it attractive for installation of PV systems. Participating owners of small PV systems would instruct inverter manufacturers to copy the daily e-mails to PVRG and as necessary, will authorize the PVRG to carry out review of PV systems. The presentation will consist of overall activities of PVRG in USA and Brazil.

Future contingencies and photovoltaic system worth

NASA Astrophysics Data System (ADS)

Jones, G. J.; Thomas, M. G.; Bonk, G. J.

1982-09-01

The value of dispersed photovoltaic systems connected to the utility grid was calculated using the optimized generation planning program. The 1986 to 2001 time period was used for this study. Photovoltaic systems were dynamically integrated, up to 5% total capacity, into 9 NERC based regions under a range of future fuel and economic contingencies. Value was determined by the change in revenue requirements due to the photovoltaic additions. Displacement of high cost fuel was paramount to value, while capacity displacement was highly variable and dependent upon regional fuel mix.

Potential and Innovations in Rooftop Photovoltaics

NASA Astrophysics Data System (ADS)

Bierman, Ben

2011-11-01

Photovoltaic technology has reached a point where its cost and capability make it one of a handful of carbon-free sources of electrical energy that could meet a meaningful fraction of US energy demand. In this paper we will first compare Photovoltaics with several other carbon free energy technologies, then look at the economics of Solyndra's rooftop photovoltaic solution as an example of the current state of the art, as well as the market dynamics that have resulted in dramatically faster adoption in Germany vs. the United States.

Photovoltaic conversion of laser energy

NASA Technical Reports Server (NTRS)

Stirn, R. J.

1976-01-01

The Schottky barrier photovoltaic converter is suggested as an alternative to the p/n junction photovoltaic devices for the conversion of laser energy to electrical energy. The structure, current, output, and voltage output of the Schottky device are summarized. The more advanced concepts of the multilayer Schottky barrier cell and the AMOS solar cell are briefly considered.

What do EMS personnel think about domestic violence? An exploration of attitudes and experiences after participation in training.

PubMed

Donnelly, Elizabeth A; Oehme, Karen; Melvin, Rebecca

2016-02-01

In 2012, the American College of Emergency Physicians (ACEP) reaffirmed that domestic violence is a serious public health hazard that emergency medical services (EMS) personnel will encounter. Many victims of domestic violence may refuse transport to the hospital, making EMS prehospital field personnel --EMTs and paramedics-- their only contact with healthcare providers. Despite these facts, the interaction of field EMS personnel and victims of domestic violence remains largely unexamined. Given the importance of the interaction of field EMS personnel have with victims of domestic violence, the goal of this study is to explore attitudes about and experiences of EMS personnel on the issue of domestic violence after completing a training on domestic violence. Participants were recruited by researchers contacting multiple EMS agencies. Data were gathered using a survey attached to an online domestic violence training for field EMS personnel (EMTs and paramedics) circulated in a large southern state. Participants were able to obtain continuing education credits for completing the online modules. A total of 403 respondents completed the survey. 71% of respondents indicated that they frequently encounter patients who disclose domestic violence; 45% believe that if a victim does not disclose abuse, there is little they can do to help; and from 32% to 43% reported assumptions and attitudes that indicate beliefs that victims are responsible for the abuse. Implications of the data are discussed suggesting that EMS providers are aware that they frequently assist victims of domestic violence, yet many continue to endorse common myths and negative attitudes about victims. Core components of training that can educate EMS personnel about the dynamics of domestic violence are described, and a new free online training for medical professionals on domestic violence is offered for use as part of ongoing education to enhance the EMS response to victims. Copyright © 2015 Elsevier Ltd

Performance simulation of a grid connected photovoltaic power system using TRNSYS 17

NASA Astrophysics Data System (ADS)

Raja Sekhar, Y.; Ganesh, D.; Kumar, A. Suresh; Abraham, Raju; Padmanathan, P.

2017-11-01

Energy plays an important role in a country’s economic growth in the current energy scenario, the major problem is depletion of energy sources (non-renewable) are more than being formed. One of the prominent solutions is minimizing the use of fossil fuels by utilization of renewable energy resources. A photovoltaic system is an efficient option in terms of utilizing the solar energy resource. The electricity output produced by the photovoltaic systems depends upon the incident solar radiation. This paper examines the performance simulation of 200KW photovoltaic power system at VIT University, Vellore. The main objective of this paper is to correlate the results between the predicted simulation data and the experimental data. The simulation tool used here is TRNSYS. Using TRNSYS modelling prediction of electricity produced throughout the year can be calculated with the help of TRNSYS weather station. The deviation of the simulated results with the experimented results varies due to the choice of weather station. Results from the field test and simulation results are to be correlated to attain the maximum performance of the system.

Status of DOE and AID stand-alone photovoltaic system field tests

NASA Astrophysics Data System (ADS)

Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

Status of DOE and AID stand-alone photovoltaic system field tests

NASA Technical Reports Server (NTRS)

Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

1984-01-01

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

Non-destructive evaluation of water ingress in photovoltaic modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bora, Mihail; Kotovsky, Jack

Systems and techniques for non-destructive evaluation of water ingress in photovoltaic modules include and/or are configured to illuminate a photovoltaic module comprising a photovoltaic cell and an encapsulant with at least one beam of light having a wavelength in a range from about 1400 nm to about 2700 nm; capture one or more images of the illuminated photovoltaic module, each image relating to a water content of the photovoltaic module; and determine a water content of the photovoltaic module based on the one or more images. Systems preferably include one or more of a light source, a moving mirror, amore » focusing lens, a beam splitter, a stationary mirror, an objective lens and an imaging module.« less

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.

Optimization of Electric Power Systems for Off-Grid Domestic Applications: An Argument for Wind/Photovoltaic Hybrids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jennings, W.; Green, J.

2001-01-01

The purpose of this research was to determine the optimal configuration of home power systems relevant to different regions in the United States. The hypothesis was that, regardless of region, the optimal system would be a hybrid incorporating wind technology, versus a photovoltaic hybrid system without the use of wind technology. The method used in this research was HOMER, the Hybrid Optimization Model for Electric Renewables. HOMER is a computer program that optimizes electrical configurations under user-defined circumstances. According to HOMER, the optimal system for the four regions studied (Kansas, Massachusetts, Oregon, and Arizona) was a hybrid incorporating wind technology.more » The cost differences between these regions, however, were dependent upon regional renewable resources. Future studies will be necessary, as it is difficult to estimate meteorological impacts for other regions.« less

Photovoltaic failure and degradation modes

DOE PAGES

Jordan, Dirk C.; Silverman, Timothy J.; Wohlgemuth, John H.; ...

2017-01-30

The extensive photovoltaic field reliability literature was analyzed and reviewed. Future work is prioritized based upon information assembled from recent installations, and inconsistencies in degradation mode identification are discussed to help guide future publication on this subject. Reported failure rates of photovoltaic modules fall mostly in the range of other consumer products; however, the long expected useful life of modules may not allow for direct comparison. In general, degradation percentages are reported to decrease appreciably in newer installations that are deployed after the year 2000. However, these trends may be convoluted with varying manufacturing and installation quality world-wide. Modules inmore » hot and humid climates show considerably higher degradation modes than those in desert and moderate climates, which warrants further investigation. Delamination and diode/j-box issues are also more frequent in hot and humid climates than in other climates. The highest concerns of systems installed in the last 10 years appear to be hot spots followed by internal circuitry discoloration. Encapsulant discoloration was the most common degradation mode, particularly in older systems. In newer systems, encapsulant discoloration appears in hotter climates, but to a lesser degree. Lastly, thin-film degradation modes are dominated by glass breakage and absorber corrosion, although the breadth of information for thin-film modules is much smaller than for x-Si.« less

Photovoltaic failure and degradation modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, Dirk C.; Silverman, Timothy J.; Wohlgemuth, John H.

The extensive photovoltaic field reliability literature was analyzed and reviewed. Future work is prioritized based upon information assembled from recent installations, and inconsistencies in degradation mode identification are discussed to help guide future publication on this subject. Reported failure rates of photovoltaic modules fall mostly in the range of other consumer products; however, the long expected useful life of modules may not allow for direct comparison. In general, degradation percentages are reported to decrease appreciably in newer installations that are deployed after the year 2000. However, these trends may be convoluted with varying manufacturing and installation quality world-wide. Modules inmore » hot and humid climates show considerably higher degradation modes than those in desert and moderate climates, which warrants further investigation. Delamination and diode/j-box issues are also more frequent in hot and humid climates than in other climates. The highest concerns of systems installed in the last 10 years appear to be hot spots followed by internal circuitry discoloration. Encapsulant discoloration was the most common degradation mode, particularly in older systems. In newer systems, encapsulant discoloration appears in hotter climates, but to a lesser degree. Lastly, thin-film degradation modes are dominated by glass breakage and absorber corrosion, although the breadth of information for thin-film modules is much smaller than for x-Si.« less

A solar photovoltaic power system for use in Antarctica

NASA Astrophysics Data System (ADS)

Kohout, Lisa L.; Colozza, A. J.; Merolla, A.

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys and provided a six-person field team with the power to run personal computers and printers, lab equipment, lightning, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering 1.5 kW peak power, three lead-acid gel battery modules supplying 2.4 kWh, and electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for each of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both and environmental and cost standpoint is interested in the use of alternate forms of energy, such as solar power. Such a power system will also provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

A solar photovoltaic power system for use in Antarctica

NASA Astrophysics Data System (ADS)

Kohout, Lisa L.; Merolla, Anthony; Colozza, Anthony

1993-12-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys, and provided a six-person field team with electrical power for personal computers and printers, lab equipment, lighting, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering a total of 1.5 kWe peak power, three lead-acid gel battery modules supplying 2.4 kWh, and an electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for ease of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both an environmental and cost standpoint, is interested in the use of alternate forms of energy, such as solar power. Such a power system also will provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

A solar photovoltaic power system for use in Antarctica

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.; Merolla, Anthony; Colozza, Anthony

1993-01-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys, and provided a six-person field team with electrical power for personal computers and printers, lab equipment, lighting, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering a total of 1.5 kWe peak power, three lead-acid gel battery modules supplying 2.4 kWh, and an electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for ease of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both an environmental and cost standpoint, is interested in the use of alternate forms of energy, such as solar power. Such a power system also will provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

A solar photovoltaic power system for use in Antarctica

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.; Colozza, A. J.; Merolla, A.

1994-01-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys and provided a six-person field team with the power to run personal computers and printers, lab equipment, lightning, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering 1.5 kW peak power, three lead-acid gel battery modules supplying 2.4 kWh, and electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for each of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both and environmental and cost standpoint is interested in the use of alternate forms of energy, such as solar power. Such a power system will also provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

Field evaluation and health assessment of air cleaners in removing radon decay products in domestic environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Chih-Shan.

In this study, field evaluations of two types of air cleaners were conducted in three single-family houses. The measurements included radon concentration, particle number concentration, and concentration and size distribution of radon decay products. The influence on the behavior of radon decay products by various indoor particles both with and without the air cleaning systems was investigated. A room model was used to calculate the changes in the aerosol parameters caused by the operation of the air cleaners. Using the James dosimetric models (1989 and 1990), the changes in the hourly bronchial dose rate per Bq m{sup {minus}3} radon formore » men, women, and children can be estimated for various domestic environments. 94 refs., 60 figs., 28 tabs.« less

Cost-Reduction Roadmap for Residential Solar Photovoltaics (PV),

Science.gov Websites

2017-2030 | Solar Research | NREL Cost-Reduction Roadmap for Residential Solar Photovoltaics (PV), 2017-2030 Cost-Reduction Roadmap for Residential Solar Photovoltaics (PV), 2017-2030 This report Office (SETO) residential 2030 photovoltaics (PV) cost target of $0.05 per kilowatt-hour by identifying

Assessing elements of an extended evolutionary synthesis for plant domestication and agricultural origin research

PubMed Central

Piperno, Dolores R.

2017-01-01

The development of agricultural societies, one of the most transformative events in human and ecological history, was made possible by plant and animal domestication. Plant domestication began 12,000–10,000 y ago in a number of major world areas, including the New World tropics, Southwest Asia, and China, during a period of profound global environmental perturbations as the Pleistocene epoch ended and transitioned into the Holocene. Domestication is at its heart an evolutionary process, and for many prehistorians evolutionary theory has been foundational in investigating agricultural origins. Similarly, geneticists working largely with modern crops and their living wild progenitors have documented some of the mechanisms that underwrote phenotypic transformations from wild to domesticated species. Ever-improving analytic methods for retrieval of empirical data from archaeological sites, together with advances in genetic, genomic, epigenetic, and experimental research on living crop plants and wild progenitors, suggest that three fields of study currently little applied to plant domestication processes may be necessary to understand these transformations across a range of species important in early prehistoric agriculture. These fields are phenotypic (developmental) plasticity, niche construction theory, and epigenetics with transgenerational epigenetic inheritance. All are central in a controversy about whether an Extended Evolutionary Synthesis is needed to reconceptualize how evolutionary change occurs. An exploration of their present and potential utility in domestication study shows that all three fields have considerable promise in elucidating important issues in plant domestication and in agricultural origin and dispersal research and should be increasingly applied to these issues. PMID:28576881

National Center for Photovoltaics at NREL

ScienceCinema

VanSant, Kaitlyn; Wilson, Greg; Berry, Joseph; Al-Jassim, Mowafak; Kurtz, Sarah

2018-06-08

The National Center for Photovoltaics at the National Renewable Energy Laboratory (NREL) focuses on technology innovations that drive industry growth in U.S. photovoltaic (PV) manufacturing. The NCPV is a central resource for our nation's capabilities in PV research, development, deployment, and outreach.

A photovoltaic device structure based on internal electron emission.

PubMed

McFarland, Eric W; Tang, Jing

2003-02-06

There has been an active search for cost-effective photovoltaic devices since the development of the first solar cells in the 1950s (refs 1-3). In conventional solid-state solar cells, electron-hole pairs are created by light absorption in a semiconductor, with charge separation and collection accomplished under the influence of electric fields within the semiconductor. Here we report a multilayer photovoltaic device structure in which photon absorption instead occurs in photoreceptors deposited on the surface of an ultrathin metal-semiconductor junction Schottky diode. Photoexcited electrons are transferred to the metal and travel ballistically to--and over--the Schottky barrier, so providing the photocurrent output. Low-energy (approximately 1 eV) electrons have surprisingly long ballistic path lengths in noble metals, allowing a large fraction of the electrons to be collected. Unlike conventional cells, the semiconductor in this device serves only for majority charge transport and separation. Devices fabricated using a fluorescein photoreceptor on an Au/TiO2/Ti multilayer structure had typical open-circuit photovoltages of 600-800 mV and short-circuit photocurrents of 10-18 micro A cm(-2) under 100 mW cm(-2) visible band illumination: the internal quantum efficiency (electrons measured per photon absorbed) was 10 per cent. This alternative approach to photovoltaic energy conversion might provide the basis for durable low-cost solar cells using a variety of materials.

Domestic violence.

PubMed

Bennett, B

1997-01-01

This article explores the usefulness of white feminist domestic intervention to Aboriginal women who are victims of domestic violence. The discussion opens with a brief history of Aboriginal society before the age of colonization, followed by a summary of feminist intervention to fight domestic violence and the reactions of the Aboriginal women and communities towards this. It also presents a brief description of works conducted overseas where more appropriate frameworks are being used in intervening against domestic violence such as anti-racist social work. Towards the end, this paper explores some future possibilities for workers, in both Aboriginal and non-Aboriginal societies.

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.

Polycrystalline Thin-Film Photovoltaics | Photovoltaic Research | NREL

Science.gov Websites

(CdTe) We develop processes and a range of materials for CdTe photovoltaic (PV) devices. Our work partners. Our objectives are to improve CdTe PV performance, reduce costs, and advance fundamental processes and materials related to thin-film polycrystalline PV devices, and our measurements and

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.

Direct mounted photovoltaic device with improved side clip

DOEpatents

Keenihan, James R; Boven, Michelle L; Brown, Jr., Claude; Eurich, Gerald K; Gaston, Ryan S; Hus, Michael

2013-11-19

The present invention is premised upon a photovoltaic assembly system for securing and/or aligning at least a plurality of vertically adjacent photovoltaic device assemblies to one another. The securing function being accomplished by a clip member that may be a separate component or integral to one or more of the photovoltaic device assemblies.

Direct mounted photovoltaic device with improved front clip

DOEpatents

Keenihan, James R; Boven, Michelle; Brown, Jr., Claude; Gaston, Ryan S; Hus, Michael; Langmaid, Joe A; Lesniak, Mike

2013-11-05

The present invention is premised upon a photovoltaic assembly system for securing and/or aligning at least a plurality of vertically adjacent (overlapping) photovoltaic device assemblies to one another. The securing function being accomplished by a clip member that may be a separate component or integral to one or more of the photovoltaic device assemblies.

From wild animals to domestic pets, an evolutionary view of domestication.

PubMed

Driscoll, Carlos A; Macdonald, David W; O'Brien, Stephen J

2009-06-16

Artificial selection is the selection of advantageous natural variation for human ends and is the mechanism by which most domestic species evolved. Most domesticates have their origin in one of a few historic centers of domestication as farm animals. Two notable exceptions are cats and dogs. Wolf domestication was initiated late in the Mesolithic when humans were nomadic hunter-gatherers. Those wolves less afraid of humans scavenged nomadic hunting camps and over time developed utility, initially as guards warning of approaching animals or other nomadic bands and soon thereafter as hunters, an attribute tuned by artificial selection. The first domestic cats had limited utility and initiated their domestication among the earliest agricultural Neolithic settlements in the Near East. Wildcat domestication occurred through a self-selective process in which behavioral reproductive isolation evolved as a correlated character of assortative mating coupled to habitat choice for urban environments. Eurasian wildcats initiated domestication and their evolution to companion animals was initially a process of natural, rather than artificial, selection over time driven during their sympatry with forbear wildcats.

An investigation of the effect of wind cooling on photovoltaic arrays

NASA Technical Reports Server (NTRS)

Wen, L.

1982-01-01

Convective cooling of photovoltaic modules for different wind conditions, including steady state controlled testing in a solar simulator and natural test environments in a field was investigated. Analytical thermal models of different module designs were used to correlate experimental data. The applicability of existing heat transfer correlations is confirmed. Reasonable agreement is obtained by applying a power law wind profile.

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.

Solar photovoltaics: current state and trends

NASA Astrophysics Data System (ADS)

Milichko, V. A.; Shalin, A. S.; Mukhin, I. S.; Kovrov, A. E.; Krasilin, A. A.; Vinogradov, A. V.; Belov, P. A.; Simovski, C. R.

2016-08-01

Basic aspects of current solar photovoltaics (PVs) are reviewed, starting from the recently developed already-on-the-market first-generation solar cells and ending with promising but not yet commercialized third-generation cells and materials possibly leading to new cell designs. The emphasis is on the physical principles of operation of various solar cells, which are divided into several groups according to our classification scheme. To make the picture complete, some technological and economic aspects of the field are discussed. A separate chapter considers antireflection coatings and light-trapping textures — structures which, while not having appeared yet in the PV review literature, are an integral part of the solar cells.

Effect of industrial and domestic ash from biomass combustion, and spent coffee grounds, on soil fertility and plant growth: experiments at field conditions.

PubMed

Ribeiro, João Peres; Vicente, Estela Domingos; Gomes, Ana Paula; Nunes, Maria Isabel; Alves, Célia; Tarelho, Luís A C

2017-06-01

An experimental study was conducted at field conditions in order to evaluate the effect of application of ash from biomass combustion on some soil fertility characteristics and plant growth. Application of 7.5 Mg ha -1 industrial fly ash (IA), domestic ash (DA), and a 50:50 mix of domestic ash (DA) and spent coffee grounds (SCG) was made in different soil parcels. Lolium perenne seeds were sown and the grown biomass was harvested and quantified after 60 days. Soil samples from each parcel were also collected after that period and characterized. Both soil and grown biomass samples were analyzed for Ca, Mg, Na, K, P, Fe, Mn, Zn, and Al contents. Soil pH was determined before and after amendment. All applications rose significantly soil pH. Domestic ash, whether combined with coffee grounds or not, proved to be efficient at supplying available macronutrients Ca, Mg, K, and P to the soil and also reducing availability of Al (more than industrial ash). However, it inhibited plant growth, even more when combined with spent coffee grounds. As regards to elemental abundance in plant tissue, both domestic ash treatments reduced Ca and enhanced Al contents, unlike industrial ash, which proved less harmful for the load applied in the soil. Hence, it was possible to conclude that application load should be a limiting factor for this management option for the studied materials.

Isolation transformers for utility-interactive photovoltaic systems

NASA Astrophysics Data System (ADS)

Kern, E. C., Jr.

1982-12-01

Isolation transformers are used in some photovoltaic systems to isolate the photovoltaic system common mode voltage from the utility distribution system. In early system experiments with grid connected photovoltaics, such transformers were the source of significant power losses. A project at the Lincoln Laboratory and at Allied Chemical Corporation developed an improved isolation transformer to minimize such power losses. Experimental results and an analytical model of conventional and improved transformers are presented, showing considerable reductions of losses associated with the improved transformer.

Photovoltaic power systems for rural areas of developing countries

NASA Technical Reports Server (NTRS)

Rosenblum, L.; Bifano, W. J.; Hein, G. F.; Ratajczak, A. F.

1979-01-01

Systems technology, reliability, and present and projected costs of photovoltaic systems are discussed using data derived from NASA, Lewis Research Center experience with photovoltaic systems deployed with a variety of users. Operating systems in two villages, one in Upper Volta and the other in southwestern Arizona are described. Energy cost comparisons are presented for photovoltaic systems versus alternative energy sources. Based on present system technology, reliability, and costs, photovoltaics provides a realistic energy option for developing nations.

High-Efficiency Crystalline Photovoltaics | Photovoltaic Research | NREL

Science.gov Websites

. We are key players in developing low-cost, manufacturable techniques for further increasing the also a driving force in two industry-relevant areas: low-cost III-V photovoltaic cells for 1-sun and are developing a >23%-efficiency, low-cost industrial-size cell on n-Cz wafer by 2018. Silicon

Functionalized graphene and other two-dimensional materials for photovoltaic devices: device design and processing.

PubMed

Liu, Zhike; Lau, Shu Ping; Yan, Feng

2015-08-07

Graphene is the thinnest two-dimensional (2D) carbon material and has many advantages including high carrier mobilities and conductivity, high optical transparency, excellent mechanical flexibility and chemical stability, which make graphene an ideal material for various optoelectronic devices. The major applications of graphene in photovoltaic devices are for transparent electrodes and charge transport layers. Several other 2D materials have also shown advantages in charge transport and light absorption over traditional semiconductor materials used in photovoltaic devices. Great achievements in the applications of 2D materials in photovoltaic devices have been reported, yet numerous challenges still remain. For practical applications, the device performance should be further improved by optimizing the 2D material synthesis, film transfer, surface functionalization and chemical/physical doping processes. In this review, we will focus on the recent advances in the applications of graphene and other 2D materials in various photovoltaic devices, including organic solar cells, Schottky junction solar cells, dye-sensitized solar cells, quantum dot-sensitized solar cells, other inorganic solar cells, and perovskite solar cells, in terms of the functionalization techniques of the materials, the device design and the device performance. Finally, conclusions and an outlook for the future development of this field will be addressed.

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.

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.

High-efficiency photovoltaic technology including thermoelectric generation

NASA Astrophysics Data System (ADS)

Fisac, Miguel; Villasevil, Francesc X.; López, Antonio M.

2014-04-01

Nowadays, photovoltaic solar energy is a clean and reliable source for producing electric power. Most photovoltaic systems have been designed and built up for use in applications with low power requirements. The efficiency of solar cells is quite low, obtaining best results in monocrystalline silicon structures, with an efficiency of about 18%. When temperature rises, photovoltaic cell efficiency decreases, given that the short-circuit current is slightly increased, and the open-circuit voltage, fill factor and power output are reduced. To ensure that this does not affect performance, this paper describes how to interconnect photovoltaic and thermoelectric technology into a single structure. The temperature gradient in the solar panel is used to supply thermoelectric cells, which generate electricity, achieving a positive contribution to the total balance of the complete system.

76 FR 55892 - Nationwide Limited Public Interest Waiver Under Section 1605 (Buy American) of the American...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-09

... following solar photo-voltaic (PV) equipment: (1) Domestically-manufactured modules containing foreign... inconsistent with the public interest for incidental and/or ancillary solar Photovoltaic (PV) equipment, when this equipment is utilized in solar installations containing domestically manufactured PV cells or...

Photovoltaic performance and the energy landscape of CH3NH3PbI3.

PubMed

Zhou, Yecheng; Huang, Fuzhi; Cheng, Yi-Bing; Gray-Weale, Angus

2015-09-21

Photovoltaic cells with absorbing layers of certain perovskites have power conversion efficiencies up to 20%. Among these materials, CH3NH3PbI3 is widely used. Here we use density-functional theory to calculate the energies and rotational energy barriers of a methylammonium ion in the α or β phase of CH3NH3PbI3 with differently oriented neighbouring methylammonium ions. Our results suggest the methylammonium ions in CH3NH3PbI3 prefer to rotate collectively, and to be parallel to their neighbours. Changes in polarization on rotation of methylammonium ions are two to three times larger than those on relaxation of the lead ion from the centre of its coordination shell. The preferences for parallel configuration and concerted rotation, with the polarisation changes, are consistent with ferroelectricity in the material, and indicate that this polarisation is governed by methylammonium orientational correlations. We show that the field due to this polarisation is strong enough to screen the field hindering charge transport, and find this screening field in agreement with experiment. We examine two possible mechanisms for the effect of methylammonium ion rotation on photovoltaic performance. One is that rearrangement of methylammoniums promotes the creation and transport of charge carriers. Some effective masses change greatly, but changes in band structure with methylammonium rotation are not large enough to explain current-voltage hysteresis behaviour. The second possible mechanism is that polarization screens the hindering electric field, which arises from charge accumulation in the transport layers. Polarization changes on methylammonium rotation favour this second mechanism, suggesting that collective reorientation of methylammonium ions in the bulk crystal are in significant part responsible for the hysteresis and power conversion characteristics of CH3NH3PbI3 photovoltaic cells.

Flate-plate photovoltaic power systems handbook for Federal agencies

NASA Technical Reports Server (NTRS)

Cochrane, E. H.; Lawson, A. C.; Savage, C. H.

1984-01-01

The primary purpose is to provide a tool for personnel in Federal agencies to evaluate the viability of potential photovoltaic applications. A second objective is to provide descriptions of various photovoltaic systems installed by different Federal agencies under the Federal Photovoltaic Utilization Program so that other agencies may consider similar applications. A third objective is to share lessons learned to enable more effective procurement, design, installation, and operation of future photovoltaic systems. The intent is not to provide a complete handbook, but rather to provide a guide for Federal agency personnel with additional information incorporated by references. The steps to be followed in selecting, procuring, and installing a photovoltaic application are given.

Impact to Underground Sources of Drinking Water and Domestic Wells from Production Well Stimulation and Completion Practices in the Pavillion, Wyoming, Field.

PubMed

DiGiulio, Dominic C; Jackson, Robert B

2016-04-19

A comprehensive analysis of all publicly available data and reports was conducted to evaluate impact to Underground Sources of Drinking Water (USDWs) as a result of acid stimulation and hydraulic fracturing in the Pavillion, WY, Field. Although injection of stimulation fluids into USDWs in the Pavillion Field was documented by EPA, potential impact to USDWs at the depths of stimulation as a result of this activity was not previously evaluated. Concentrations of major ions in produced water samples outside expected levels in the Wind River Formation, leakoff of stimulation fluids into formation media, and likely loss of zonal isolation during stimulation at several production wells, indicates that impact to USDWs has occurred. Detection of organic compounds used for well stimulation in samples from two monitoring wells installed by EPA, plus anomalies in major ion concentrations in water from one of these monitoring wells, provide additional evidence of impact to USDWs and indicate upward solute migration to depths of current groundwater use. Detections of diesel range organics and other organic compounds in domestic wells <600 m from unlined pits used prior to the mid-1990s to dispose diesel-fuel based drilling mud and production fluids suggest impact to domestic wells as a result of legacy pit disposal practices.

System Dynamics of Polysilicon for Solar Photovoltaics: A Framework for Investigating the Energy Security of Renewable Energy Supply Chains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandor, Debra; Fulton, Sadie; Engel-Cox, Jill

Renewable energy, produced with widely available low-cost energy resources, is often included as a component of national strategies to address energy security and sustainability. Market and political forces cannot disrupt the sun or wind, unlike oil and gas supplies. However, the cost of renewable energy is highly dependent on technologies manufactured through global supply chains in leading manufacturing countries. The countries that contribute to the global supply chains may take actions that, directly or indirectly, influence global access to materials and components. For example, high-purity polysilicon, a key material in solar photovoltaics, has experienced significant price fluctuations, affecting the manufacturingmore » capacity and cost of both polysilicon and solar panels. This study has developed and validated an initial system dynamics framework to gain insights into global trade in polysilicon. The model represents an initial framework for exploration. Three regions were modeled-China, the United States, and the rest of the world - for a range of trade scenarios to understand the impacts of import duties and non-price drivers on the relative volumes of imports and domestic supply. The model was validated with the historical case of China imposing an import duty on polysilicon from the United States, the European Union, and South Korea, which altered the regional flows of polysilicon - in terms of imports, exports, and domestic production-to varying degrees. As expected, the model tracked how regional demand shares and influx volumes decrease as a duty on a region increases. Using 2016 as a reference point, in the scenarios examined for U.S. exports to China, each 10% increase in the import duty results in a 40% decrease in import volume. The model also indicates that, under the scenarios investigated, once a duty has been imposed on a region, the demand share from that region declines and does not achieve pre-duty levels, even as global demand

System Dynamics of Polysilicon for Solar Photovoltaics: A Framework for Investigating the Energy Security of Renewable Energy Supply Chains

DOE PAGES

Sandor, Debra; Fulton, Sadie; Engel-Cox, Jill; ...

2018-01-11

Renewable energy, produced with widely available low-cost energy resources, is often included as a component of national strategies to address energy security and sustainability. Market and political forces cannot disrupt the sun or wind, unlike oil and gas supplies. However, the cost of renewable energy is highly dependent on technologies manufactured through global supply chains in leading manufacturing countries. The countries that contribute to the global supply chains may take actions that, directly or indirectly, influence global access to materials and components. For example, high-purity polysilicon, a key material in solar photovoltaics, has experienced significant price fluctuations, affecting the manufacturingmore » capacity and cost of both polysilicon and solar panels. This study has developed and validated an initial system dynamics framework to gain insights into global trade in polysilicon. The model represents an initial framework for exploration. Three regions were modeled-China, the United States, and the rest of the world - for a range of trade scenarios to understand the impacts of import duties and non-price drivers on the relative volumes of imports and domestic supply. The model was validated with the historical case of China imposing an import duty on polysilicon from the United States, the European Union, and South Korea, which altered the regional flows of polysilicon - in terms of imports, exports, and domestic production-to varying degrees. As expected, the model tracked how regional demand shares and influx volumes decrease as a duty on a region increases. Using 2016 as a reference point, in the scenarios examined for U.S. exports to China, each 10% increase in the import duty results in a 40% decrease in import volume. The model also indicates that, under the scenarios investigated, once a duty has been imposed on a region, the demand share from that region declines and does not achieve pre-duty levels, even as global demand

Photovoltaic spatial solitons affected by a resistor in the external circuit

NASA Astrophysics Data System (ADS)

Wang, Xiao Sheng; She, Wei Long

2002-09-01

We have found that the FWHM of one-dimensional photovoltaic spatial soliton is modified by the space-charge field in the crystal, which can be controlled by a resistor in the external circuit. In this case, the photovoltaic contribution of a background beam is taken into account. In a crystal with a positive perturbation of refractive index, the FWHM of dark soliton decreases with the resistance of the resistor, while the FWHM of bright soliton increases with the resistance. Furthermore, when R (the ratio of the effective Glass constant of a signal beam over a background beam) is higher than 1, we can switch a dark soliton to a bright soliton by decreasing the resistance or vice versa. During such process, both the wavelengths and the intensities of the signal beam and the background beam are kept unchanged.

Work with Us | Photovoltaic Research | NREL

Science.gov Websites

Research Facility (SERF) Science and Technology Facility (S&TF) Outdoor Test Facility (OTF) Energy the Hands On Photovoltaic Experience (HOPE). Photo of a researcher in a lab Photovoltaic research and related activities occur in various locations across the NREL campus, including the Solar Energy Research

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.

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.

Central station market development strategies for photovoltaics

NASA Astrophysics Data System (ADS)

1980-11-01

Federal market development strategies designed to accelerate the market penetration of central station applications of photovoltaic energy system are analyzed. Since no specific goals were set for the commercialization of central station applications, strategic principles are explored which, when coupled with specific objectives for central stations, can produce a market development implementation plan. The study includes (1) background information on the National Photovoltaic Program, photovoltaic technology, and central stations; (2) a brief market assessment; (3) a discussion of the viewpoints of the electric utility industry with respect to solar energy; (4) a discussion of commercialization issues; and (5) strategy principles. It is recommended that a set of specific goals and objectives be defined for the photovoltaic central station program, and that these goals and objectives evolve into an implementation plan that identifies the appropriate federal role.

Central station market development strategies for photovoltaics

NASA Technical Reports Server (NTRS)

1980-01-01

Federal market development strategies designed to accelerate the market penetration of central station applications of photovoltaic energy system are analyzed. Since no specific goals were set for the commercialization of central station applications, strategic principles are explored which, when coupled with specific objectives for central stations, can produce a market development implementation plan. The study includes (1) background information on the National Photovoltaic Program, photovoltaic technology, and central stations; (2) a brief market assessment; (3) a discussion of the viewpoints of the electric utility industry with respect to solar energy; (4) a discussion of commercialization issues; and (5) strategy principles. It is recommended that a set of specific goals and objectives be defined for the photovoltaic central station program, and that these goals and objectives evolve into an implementation plan that identifies the appropriate federal role.

Photovoltaic: Instructional Manual. The North Dakota High Technology Mobile Laboratory Project.

ERIC Educational Resources Information Center

Auer, Herbert J.

This instructional manual contains 11 learning activity packets for use in a workshop on photovoltaic converters. The lessons cover the following topics: introduction; solar radiation--input for photovoltaic converters; photovoltaic cells; solar electric generator systems; characteristics of silicon cells; photovoltaic module source resistance;…

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.

Systems and methods for photovoltaic string protection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krein, Philip T.; Kim, Katherine A.; Pilawa-Podgurski, Robert C. N.

A system and method includes a circuit for protecting a photovoltaic string. A bypass switch connects in parallel to the photovoltaic string and a hot spot protection switch connects in series with the photovoltaic string. A first control signal controls opening and closing of the bypass switch and a second control signal controls opening and closing of the hot spot protection switch. Upon detection of a hot spot condition the first control signal closes the bypass switch and after the bypass switch is closed the second control signal opens the hot spot protection switch.

Photovoltaic sheathing element with one or more tabs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keenihan, James R; Langmaid, Joseph A; Lopez, Leonardo C.

2017-02-07

The present invention is premised upon an assembly that includes at least a photovoltaic sheathing element capable of being affixed on a building structure. The shingle including at least a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly. Wherein the body portion includes one or more top peripheral tabs each capable of fitting under one or more vertically adjoining devices.

Photovoltaics as a terrestrial energy source. Volume 1: An introduction

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Photovoltaic (PV) systems were examined their potential for terrestrial application and future development. Photovoltaic technology, existing and potential photovoltaic applications, and the National Photovoltaics Program are reviewed. The competitive environment for this electrical source, affected by the presence or absence of utility supplied power is evaluated in term of systems prices. The roles of technological breakthroughs, directed research and technology development, learning curves, and commercial demonstrations in the National Program are discussed. The potential for photovoltaics to displace oil consumption is examined, as are the potential benefits of employing PV in either central-station or non-utility owned, small, distributed systems.

Efficiency optimization of a photovoltaic water pumping system for irrigation in Ouargla, Algeria

NASA Astrophysics Data System (ADS)

Louazene, M. L.; Garcia, M. C. Alonso; Korichi, D.

2017-02-01

This work is technical study to contribute to the optimization of pumping systems powered by solar energy (clean) and used in the field of agriculture. To achieve our goals, we studied the techniques that must be entered on a photovoltaic system for maximum energy from solar panels. Our scientific contribution in this research is the realization of an efficient photovoltaic pumping system for irrigation needs. To achieve this and extract maximum power from the PV generator, two axes have been optimized: 1. Increase in the uptake of solar radiation by choice an optimum tilt angle of the solar panels, and 2. it is necessary to add an adaptation device, MPPT controller with a DC-DC converter, between the source and the load.

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.

A Wearable All-Solid Photovoltaic Textile.

PubMed

Zhang, Nannan; Chen, Jun; Huang, Yi; Guo, Wanwan; Yang, Jin; Du, Jun; Fan, Xing; Tao, Changyuan

2016-01-13

A solution is developed to power portable electronics in a wearable manner by fabricating an all-solid photovoltaic textile. In a similar way to plants absorbing solar energy for photosynthesis, humans can wear the as-fabricated photovoltaic textile to harness solar energy for powering small electronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photovoltaic Manufacturing R&D Project | Photovoltaic Research | NREL

Science.gov Websites

Photovoltaic (PV) Manufacturing Research and Development (R&D) Project was a cost-shared partnership between NREL and a number of private-sector solar companies. The primary project goals were to reduce costs for consumers and solar companies by improving products and manufacturing processes and ensure the

Photovoltaic power systems workshop

NASA Technical Reports Server (NTRS)

Killian, H. J.; Given, R. W.

1978-01-01

Discussions are presented on apparent deficiencies in NASA planning and technology development relating to a standard power module (25-35 kW) and to future photovoltaic power systems in general. Topics of discussion consider the following: (1) adequate studies on power systems; (2) whether a standard power system module should be developed from a standard spacecraft; (3) identification of proper approaches to cost reduction; (4) energy storage avoidance; (5) attitude control; (6) thermal effects of heat rejection on solar array configuration stability; (7) assembly of large power systems in space; and (8) factoring terrestrial photovoltaic work into space power systems for possible payoff.

The research on thermal adaptability reinforcement technology for photovoltaic modules

NASA Astrophysics Data System (ADS)

Su, Nana; Zhou, Guozhong

2015-10-01

Nowadays, Photovoltaic module contains more high-performance components in smaller space. It is also demanded to work in severe temperature condition for special use, such as aerospace. As temperature rises, the failure rate will increase exponentially which makes reliability significantly reduce. In order to improve thermal adaptability of photovoltaic module, this paper makes a research on reinforcement technologies. Thermoelectric cooler is widely used in aerospace which has harsh working environment. So, theoretical formulas for computing refrigerating efficiency, refrigerating capacity and temperature difference are described in detail. The optimum operating current of three classical working condition is obtained which can be used to guide the design of driven circuit. Taken some equipment enclosure for example, we use thermoelectric cooler to reinforce its thermal adaptability. By building physical model and thermal model with the aid of physical dimension and constraint condition, the model is simulated by Flotherm. The temperature field cloud is shown to verify the effectiveness of reinforcement.

A graphene/single GaAs nanowire Schottky junction photovoltaic device.

PubMed

Luo, Yanbin; Yan, Xin; Zhang, Jinnan; Li, Bang; Wu, Yao; Lu, Qichao; Jin, Chenxiaoshuai; Zhang, Xia; Ren, Xiaomin

2018-05-17

A graphene/nanowire Schottky junction is a promising structure for low-cost high-performance optoelectronic devices. Here we demonstrate a graphene/single GaAs nanowire Schottky junction photovoltaic device. The Schottky junction is fabricated by covering a single layer graphene onto an n-doped GaAs nanowire. Under 532 nm laser excitation, the device exhibits a high responsivity of 231 mA W-1 and a short response/recover time of 85/118 μs at zero bias. Under AM 1.5 G solar illumination, the device has an open-circuit voltage of 75.0 mV and a short-circuit current density of 425 mA cm-2, yielding a remarkable conversion efficiency of 8.8%. The excellent photovoltaic performance of the device is attributed to the strong built-in electric field in the Schottky junction as well as the transparent property of graphene. The device is promising for self-powered high-speed photodetectors and low-cost high-efficiency solar cells.

Recent Advances in Morphology Optimization for Organic Photovoltaics.

PubMed

Lee, Hansol; Park, Chaneui; Sin, Dong Hun; Park, Jong Hwan; Cho, Kilwon

2018-06-19

Organic photovoltaics are an important part of a next-generation energy-harvesting technology that uses a practically infinite pollutant-free energy source. They have the advantages of light weight, solution processability, cheap materials, low production cost, and deformability. However, to date, the moderate photovoltaic efficiencies and poor stabilities of organic photovoltaics impede their use as replacements for inorganic photovoltaics. Recent developments in bulk-heterojunction organic photovoltaics mean that they have almost reached the lower efficiency limit for feasible commercialization. In this review article, the recent understanding of the ideal bulk-heterojunction morphology of the photoactive layer for efficient exciton dissociation and charge transport is described, and recent attempts as well as early-stage trials to realize this ideal morphology are discussed systematically from a morphological viewpoint. The various approaches to optimizing morphologies consisting of an interpenetrating bicontinuous network with appropriate domain sizes and mixed regions are categorized, and in each category, the recent trends in the morphology control on the multilength scale are highlighted and discussed in detail. This review article concludes by identifying the remaining challenges for the control of active layer morphologies and by providing perspectives toward real application and commercialization of organic photovoltaics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fatigue mechanism verified using photovoltaic properties of Pb(Zr0.52Ti0.48)O3 thin films

NASA Astrophysics Data System (ADS)

Wu, Ming; Li, Wei; Li, Junning; Wang, Shaolan; Li, Yaqi; Peng, Biaolin; Huang, Haitao; Lou, Xiaojie

2017-03-01

The photovoltaic effect and its evolution during electrical fatigue in Pb(Zr0.52Ti0.48)O3 (PZT) thin films have been investigated. It is found that the photovoltaic effect of the as-grown PZT thin film is highly affected by the asymmetric Schottky barriers, which can be tuned by applying an external electric field. During fatigue processes, both open-circuit voltage (Voc) and short-circuit current (Jsc) decrease considerably with the increase of the number of electrical cycles. This phenomenon could be ascribed to the degradation of the interfacial layer between the thin film and the electrode induced by highly energetic charge carriers injected from the electrode during bipolar cycling. Our work sheds light on the physical mechanism of both ferroelectric photovoltaics and polarization fatigue in thin-film ferroelectrics.

Cadmium telluride photovoltaic radiation detector

DOEpatents

Agouridis, D.C.; Fox, R.J.

A dosimetry-type radiation detector is provided which employs a polycrystalline, chlorine-compensated cadmium telluride wafer fabricated to operate as a photovoltaic current generator used as the basic detecting element. A photovoltaic junction is formed in the wafer by painting one face of the cadmium telluride wafer with an n-type semi-conductive material. The opposite face of the wafer is painted with an electrically conductive material to serve as a current collector. The detector is mounted in a hermetically sealed vacuum containment. The detector is operated in a photovoltaic mode (zero bias) while DC coupled to a symmetrical differential current amplifier having a very low input impedance. The amplifier converts the current signal generated by radiation impinging upon the barrier surface face of the wafer to a voltage which is supplied to a voltmeter calibrated to read quantitatively the level of radiation incident upon the detecting wafer.

Cadmium telluride photovoltaic radiation detector

DOEpatents

Agouridis, Dimitrios C.; Fox, Richard J.

1981-01-01

A dosimetry-type radiation detector is provided which employs a polycrystalline, chlorine-compensated cadmium telluride wafer fabricated to operate as a photovoltaic current generator used as the basic detecting element. A photovoltaic junction is formed in the wafer by painting one face of the cadmium telluride wafer with an n-type semiconductive material. The opposite face of the wafer is painted with an electrically conductive material to serve as a current collector. The detector is mounted in a hermetically sealed vacuum containment. The detector is operated in a photovoltaic mode (zero bias) while DC coupled to a symmetrical differential current amplifier having a very low input impedance. The amplifier converts the current signal generated by radiation impinging upon the barrier surface face of the wafer to a voltage which is supplied to a voltmeter calibrated to read quantitatively the level of radiation incident upon the detecting wafer.

Basic research challenges in crystalline silicon photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Werner, J.H.

1995-08-01

Silicon is abundant, non-toxic and has an ideal band gap for photovoltaic energy conversion. Experimental world record cells of 24 % conversion efficiency with around 300 {mu}m thickness are only 4 % (absolute) efficiency points below the theoretical Auger recombination-limit of around 28 %. Compared with other photovoltaic materials, crystalline silicon has only very few disadvantages. The handicap of weak light absorbance may be mastered by clever optical designs. Single crystalline cells of only 48 {mu}m thickness showed 17.3 % efficiency even without backside reflectors. A technology of solar cells from polycrystalline Si films on foreign substrates arises at themore » horizon. However, the disadvantageous, strong activity of grain boundaries in Si could be an insurmountable hurdle for a cost-effective, terrestrial photovoltaics based on polycrystalline Si on foreign substrates. This talk discusses some basic research challenges related to a Si based photovoltaics.« less

Domestic Violence

MedlinePlus

Domestic violence is a type of abuse. It usually involves a spouse or partner, but it can also ... a child, elderly relative, or other family member. Domestic violence may include Physical violence that can lead to ...

Photovoltaics. [research and development of terrestrial electric power systems

NASA Technical Reports Server (NTRS)

Smith, J. L.

1981-01-01

The federal government has sponsored a program of research and development on terrestrial photovoltaic systems that is designed to reduce the costs of such systems through technological advances. There are many potential paths to lower system costs, and successful developments have led to increased private investment in photovoltaics. The prices for photovoltaic collectors and systems that appear to be achievable within this decade offer hope that the systems will soon be attractive in utility applications within the United States. Most of the advances achieved will also be directly applicable to the remote markets in which photovoltaic systems are now commercially successful

The role of development of photovoltaics for Mongolia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enebish, N.; Agchbayar, D.; Baatarkhuu, M.

1994-12-31

This paper describes an assessment of the potential applications of photovoltaic technology in Mongolia. Socio-economic conditions of the pastoral culture are described and it is shown that the photovoltaic system is the most suitable source of electricity and has potential for wide application. One application identified is for powering communications systems for herdspeople and other decentralized communities of Mongolian rural areas. Some strategies for the future development and application of photovoltaic systems in Mongolia are discussed.

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.

Wild genius - domestic fool? Spatial learning abilities of wild and domestic guinea pigs.

PubMed

Lewejohann, Lars; Pickel, Thorsten; Sachser, Norbert; Kaiser, Sylvia

2010-03-25

Domestic animals and their wild relatives differ in a wide variety of aspects. The process of domestication of the domestic guinea pig (Cavia aperea f. porcellus), starting at least 4500 years ago, led to changes in the anatomy, physiology, and behaviour compared with their wild relative, the wild cavy, Cavia aperea. Although domestic guinea pigs are widely used as a laboratory animal, learning and memory capabilities are often disregarded as being very scarce. Even less is known about learning and memory of wild cavies. In this regard, one striking domestic trait is a reduction in relative brain size, which in the domesticated form of the guinea pig amounts to 13%. However, the common belief, that such a reduction of brain size in the course of domestication of different species is accomplished by less learning capabilities is not at all very well established in the literature. Indeed, domestic animals might also even outperform their wild conspecifics taking advantage of their adaptation to a man-made environment.In our study we compared the spatial learning abilities of wild and domestic guinea pigs. We expected that the two forms are different regarding their learning performance possibly related to the process of domestication. Therefore wild cavies as well as domestic guinea pigs of both sexes, aged 35 to 45 days, were tested in the Morris water maze to investigate their ability of spatial learning. Both, wild cavies and domestic guinea pigs were able to learn the task, proving the water maze to be a suitable test also for wild cavies. Regarding the speed of learning, male as well as female domestic guinea pigs outperformed their wild conspecifics significantly. Interestingly, only domestic guinea pigs showed a significant spatial association of the platform position, while other effective search strategies were used by wild cavies. The results demonstrate that domestic guinea pigs do not at all perform worse than their wild relatives in tests of spatial

Wild genius - domestic fool? Spatial learning abilities of wild and domestic guinea pigs

PubMed Central

2010-01-01

Background Domestic animals and their wild relatives differ in a wide variety of aspects. The process of domestication of the domestic guinea pig (Cavia aperea f. porcellus), starting at least 4500 years ago, led to changes in the anatomy, physiology, and behaviour compared with their wild relative, the wild cavy, Cavia aperea. Although domestic guinea pigs are widely used as a laboratory animal, learning and memory capabilities are often disregarded as being very scarce. Even less is known about learning and memory of wild cavies. In this regard, one striking domestic trait is a reduction in relative brain size, which in the domesticated form of the guinea pig amounts to 13%. However, the common belief, that such a reduction of brain size in the course of domestication of different species is accomplished by less learning capabilities is not at all very well established in the literature. Indeed, domestic animals might also even outperform their wild conspecifics taking advantage of their adaptation to a man-made environment. In our study we compared the spatial learning abilities of wild and domestic guinea pigs. We expected that the two forms are different regarding their learning performance possibly related to the process of domestication. Therefore wild cavies as well as domestic guinea pigs of both sexes, aged 35 to 45 days, were tested in the Morris water maze to investigate their ability of spatial learning. Results Both, wild cavies and domestic guinea pigs were able to learn the task, proving the water maze to be a suitable test also for wild cavies. Regarding the speed of learning, male as well as female domestic guinea pigs outperformed their wild conspecifics significantly. Interestingly, only domestic guinea pigs showed a significant spatial association of the platform position, while other effective search strategies were used by wild cavies. Conclusion The results demonstrate that domestic guinea pigs do not at all perform worse than their wild

Monitoring the battery status for photovoltaic systems

NASA Astrophysics Data System (ADS)

Kim, Myungsoo; Hwang, Euijin

Photovoltaic power systems in Korea have been installed in remote islands where it is difficult to connect the utilities. Lead/acid batteries are used as an energy storage device for the stand-alone photovoltaic system. Hence, monitoring the battery status of photovoltaic systems is quite important to extend the total system service life. To monitor the state-of-charge of batteries, we adopted a current interrupt technique to measure the internal resistance of the battery. The internal resistance increases at the end of charge/discharge steps and also with cycles. The specific gravity of the electrolyte was measured in relation to the state-of-charge. A home-made optical hydrometer was utilized for automatic monitoring of the specific gravity. It is shown that the specific gravity and stratification increase with cycle number. One of the photovoltaic systems in a remote island, Ho-do, which has 90 kW peak power was checked for actual operational conditions such as solar generation, load, and battery status.

Photovoltaics and the automobile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, W.R. Jr.

1994-12-31

For years people have been in love with the automobile. Some people just enjoy using the automobile as transportation while others also enjoy the workings and operation of this fascinating machine. The automobile is not without problems of pollution and energy consumption. These problems are changing its design and construction. New clean energy sources are being analyzed and applied to power the modern automobile. A space age energy source now being considered by some and used by others to power the automobile is photovoltaics. Photovoltaics (PV) is the direct conversion of sunlight to electricity. There are a number of devicesmore » in the modern car that are electrically powered. PV could provide a clean endless supply of electricity for air conditioning, radios and other electrical components of a car. Most people have never heard of photovoltaics (PV). There has been a great deal of research in PV among energy experts. The automobile is known the world over in both use and operation. The author describes how the merging of these two technologies will benefit mankind and without damaging the environment. 12 refs.« less

Vacuum-Ultraviolet Photovoltaic Detector.

PubMed

Zheng, Wei; Lin, Richeng; Ran, Junxue; Zhang, Zhaojun; Ji, Xu; Huang, Feng

2018-01-23

Over the past two decades, solar- and astrophysicists and material scientists have been researching and developing new-generation semiconductor-based vacuum ultraviolet (VUV) detectors with low power consumption and small size for replacing traditional heavy and high-energy-consuming microchannel-detection systems, to study the formation and evolution of stars. However, the most desirable semiconductor-based VUV photovoltaic detector capable of achieving zero power consumption has not yet been achieved. With high-crystallinity multistep epitaxial grown AlN as a VUV-absorbing layer for photogenerated carriers and p-type graphene (with unexpected VUV transmittance >96%) as a transparent electrode to collect excited holes, we constructed a heterojunction device with photovoltaic detection for VUV light. The device exhibits an encouraging VUV photoresponse, high external quantum efficiency (EQE) and extremely fast tempera response (80 ns, 10 4 -10 6 times faster than that of the currently reported VUV photoconductive devices). This work has provided an idea for developing zero power consumption and integrated VUV photovoltaic detectors with ultrafast and high-sensitivity VUV detection capability, which not only allows future spacecraft to operate with longer service time and lower launching cost but also ensures an ultrafast evolution of interstellar objects.

Space power technology 21: Photovoltaics

NASA Astrophysics Data System (ADS)

Wise, Joseph

1989-04-01

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.

Dynamic of small photovoltaic systems

NASA Astrophysics Data System (ADS)

Mehrmann, A.; Kleinkauf, W.; Pigorsch, W.; Steeb, H.

The results of 1.5 yr of field-testing of two photovoltaic (PV) power plants, one equipped with an electrolyzer and H2 storage, are reported. Both systems were interconnected with the grid and featured the PV module, a power conditioning unit, ac and dc load connections, and control units. The rated power of both units was 100 Wp. The system with electrolysis was governed by control laws which maximized the electrolyzer current. The tests underscored the preference for a power conditioning unit, rather than direct output to load connections. A 1 kWp system was developed in a follow-up program and will be tested in concert with electrolysis and interconnection with several grid customers. The program is geared to eventual development of larger units for utility-size applications.

Sunflower domestication alleles support single domestication center in eastern North America

PubMed Central

Blackman, Benjamin K.; Scascitelli, Moira; Kane, Nolan C.; Luton, Harry H.; Rasmussen, David A.; Bye, Robert A.; Lentz, David L.; Rieseberg, Loren H.

2011-01-01

Phylogenetic analyses of genes with demonstrated involvement in evolutionary transitions can be an important means of resolving conflicting hypotheses about evolutionary history or process. In sunflower, two genes have previously been shown to have experienced selective sweeps during its early domestication. In the present study, we identified a third candidate early domestication gene and conducted haplotype analyses of all three genes to address a recent, controversial hypothesis about the origin of cultivated sunflower. Although the scientific consensus had long been that sunflower was domesticated once in eastern North America, the discovery of pre-Columbian sunflower remains at archaeological sites in Mexico led to the proposal of a second domestication center in southern Mexico. Previous molecular studies with neutral markers were consistent with the former hypothesis. However, only two indigenous Mexican cultivars were included in these studies, and their provenance and genetic purity have been questioned. Therefore, we sequenced regions of the three candidate domestication genes containing SNPs diagnostic for domestication from large, newly collected samples of Mexican sunflower landraces and Mexican wild populations from a broad geographic range. The new germplasm also was genotyped for 12 microsatellite loci. Our evidence from multiple evolutionarily important loci and from neutral markers supports a single domestication event for extant cultivated sunflower in eastern North America. PMID:21844335

First-principles design of nanostructured hybrid photovoltaics based on layered transition metal phosphates

DOE PAGES

Lentz, Levi C.; Kolpak, Alexie M.

2017-04-28

The performance of bulk organic and hybrid organic-inorganic heterojunction photovoltaics is often limited by high carrier recombination arising from strongly bound excitons and low carrier mobility. Structuring materials to minimize the length scales required for exciton separation and carrier collection is therefore a promising approach for improving efficiency. In this work, first-principles computations are employed to design and characterize a new class of photovoltaic materials composed of layered transition metal phosphates (TMPs) covalently bound to organic absorber molecules to form nanostructured superlattices. Using a combination of transition metal substitution and organic functionalization, the electronic structure of these materials is systematicallymore » tuned to design a new hybrid photovoltaic material predicted to exhibit very low recombination due to the presence of a local electric field and spatially isolated, high mobility, two-dimensional electron and hole conducting channels. Furthermore, this material is predicted to have a large open-circuit voltage of 1.7 V. Here, this work suggests that hybrid TMPs constitute an interesting class of materials for further investigation in the search for achieving high efficiency, high power, and low cost photo Zirconium phosphate was chosen, in part, due to previous experiment voltaics.« less

First-principles design of nanostructured hybrid photovoltaics based on layered transition metal phosphates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lentz, Levi C.; Kolpak, Alexie M.

The performance of bulk organic and hybrid organic-inorganic heterojunction photovoltaics is often limited by high carrier recombination arising from strongly bound excitons and low carrier mobility. Structuring materials to minimize the length scales required for exciton separation and carrier collection is therefore a promising approach for improving efficiency. In this work, first-principles computations are employed to design and characterize a new class of photovoltaic materials composed of layered transition metal phosphates (TMPs) covalently bound to organic absorber molecules to form nanostructured superlattices. Using a combination of transition metal substitution and organic functionalization, the electronic structure of these materials is systematicallymore » tuned to design a new hybrid photovoltaic material predicted to exhibit very low recombination due to the presence of a local electric field and spatially isolated, high mobility, two-dimensional electron and hole conducting channels. Furthermore, this material is predicted to have a large open-circuit voltage of 1.7 V. Here, this work suggests that hybrid TMPs constitute an interesting class of materials for further investigation in the search for achieving high efficiency, high power, and low cost photo Zirconium phosphate was chosen, in part, due to previous experiment voltaics.« less

Domestic violence during pregnancy in an eastern city of Turkey: a field study.

PubMed

Arslantas, Hülya; Adana, Filiz; Ergin, Filiz; Gey, Neriman; Biçer, Nejla; Kiransal, Nilüfer

2012-05-01

Violence is an increasing and important community health problem that can be seen in any area of human life. Limited studies were found about domestic violence among pregnant women and its relation with social status of women. The aim of this study was to determine the prevalence and types of domestic violence during pregnancy, factors affecting it, women's thoughts about violence, and relation between social status of women and domestic violence. This cross-sectional study was conducted on 253 pregnant women, using cluster and simple random sampling methods. Chi-square test and logistic regression analysis methods were used to analyze the data. Women who indicated that they have been exposed to violence at some point of their lives were 24.1% and who indicated that violence continued while they were pregnant were 11.1%. Physical violence was the most common type of violence reported (18.2%). It was found that women who had primary school or lower level of education and who made unwanted marriage suffered from more violence during pregnancy. It can be said that violence against pregnant women is still a social problem. In societies where gender roles are dominant, decision makers have to take necessary steps such as supporting education of girls to improve social status of women, increasing awareness among women in regard to personal rights and legal regulations which will contribute to the solution of the issue.

Optical, electrical, and magnetic field studies of organic materials for light emitting diodes and photovoltaic applications

NASA Astrophysics Data System (ADS)

Basel, Tek Prasad

We studied optical, electrical, and magnetic field responses of films and devices based on organic semiconductors that are used for organic light emitting diodes (OLEDs) and photovoltaic (OPV) solar cell applications. Our studies show that the hyperfine interaction (HFI)-mediated spin mixing is the key process underlying various magnetic field effects (MFE) and spin transport in aluminum tris(8-hydroxyquinoline)[Alq3]-based OLEDs and organic spin-valve (OSV). Conductivity-detected magnetic resonance in OLEDs and magneto-resistance (MR) in OSVs show substantial isotope dependence. In contrast, isotope-insensitive behavior in the magneto-conductance (MC) of same devices is explained by the collision of spin ½ carriers with triplet polaron pairs. We used steady state optical spectroscopy for studying the energy transfer dynamics in films and OLEDs based on host-guest blends of the fluorescent polymer and phosphorescent molecule. We have also studied the magnetic-field controlled color manipulation in these devices, which provide a strong proof for the `polaron-pair' mechanism underlying the MFE in organic devices. The critical issue that hampers organic spintronics device applications is significant magneto-electroluminescence (MEL) at room temperature (RT). Whereas inorganic spin valves (ISVs) show RT magneto-resistance, MR>80%, however, the devices do not exhibit electroluminescence (EL). In contrast, OLEDs show substantive EL emission, and are particularly attractive because of their flexibility, low cost, and potential for multicolor display. We report a conceptual novel hybrid organic/inorganic spintronics device (h-OLED), where we employ both ISV with large MR at RT, and OLED that has efficient EL emission. We investigated the charge transfer process in an OPV solar cell through optical, electrical, and magnetic field measurements of thin films and devices based on a low bandgap polymer, PTB7 (fluorinated poly-thienothiophene-benzodithiophene). We found that

Cost and Performance Model for Photovoltaic Systems

NASA Technical Reports Server (NTRS)

Borden, C. S.; Smith, J. H.; Davisson, M. C.; Reiter, L. J.

1986-01-01

Lifetime cost and performance (LCP) model assists in assessment of design options for photovoltaic systems. LCP is simulation of performance, cost, and revenue streams associated with photovoltaic power systems connected to electric-utility grid. LCP provides user with substantial flexibility in specifying technical and economic environment of application.

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

Photovoltaic generator with a spherical imaging lens for use with a paraboloidal solar reflector

DOEpatents

Angel, Roger P

2013-01-08

The invention is a generator for photovoltaic conversion of concentrated sunlight into electricity. A generator according to the invention incorporates a plurality of photovoltaic cells and is intended for operation near the focus of a large paraboloidal reflector pointed at the sun. Within the generator, the entering concentrated light is relayed by secondary optics to the cells arranged in a compact, concave array. The light is delivered to the cells at high concentration, consistent with high photovoltaic conversion efficiency and low cell cost per unit power output. Light enters the generator, preferably first through a sealing window, and passes through a field lens, preferably in the form of a full sphere or ball lens centered on the paraboloid focus. This lens forms a concentric, concave and wide-angle image of the primary reflector, where the intensity of the concentrated light is stabilized against changes in the position of concentrated light entering the generator. Receiving the stabilized light are flat photovoltaic cells made in different shapes and sizes and configured in a concave array corresponding to the concave image of a given primary reflector. Photovoltaic cells in a generator are also sized and interconnected so as to provide a single electrical output that remains high and stable, despite aberrations in the light delivered to the generator caused by, for example, mispointing or bending of the primary reflector. In some embodiments, the cells are set back from the image formed by the ball lens, and part of the light is reflected onto each cell small secondary reflectors in the form of mirrors set around its perimeter.

Genetic testing in domestic cats

PubMed Central

Lyons, Leslie A.

2012-01-01

Varieties of genetic tests are currently available for the domestic cat that support veterinary health care, breed management, species identification, and forensic investigations. Approximately thirty-five genes contain over fifty mutations that cause feline health problems or alterations in the cat’s appearance. Specific genes, such as sweet and drug receptors, have been knocked-out of Felidae during evolution and can be used along with mtDNA markers for species identification. Both STR and SNP panels differentiate cat race, breed, and individual identity, as well as gender-specific markers to determine sex of an individual. Cat genetic tests are common offerings for commercial laboratories, allowing both the veterinary clinician and the private owner to obtain DNA test results. This article will review the genetic tests for the domestic cat, and their various applications in different fields of science. Highlighted are genetic tests specific to the individual cat, which are a part of the cat’s genome. PMID:22546621

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.

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.

Photovoltaic sheathing element with a flexible connector assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langmaid, Joseph A; Keenihan, James R; Mills, Michael E

2016-07-12

The present invention is premised upon an assembly including at least a photovoltaic sheathing element capable of being affixed on a building structure, the sheathing element including at least: a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly; at least a first and a second connector assembly disposed on opposing sides of the sheathing element and capable of directly or indirectly electrically connecting the photovoltaic cell assembly to at least two adjoining devices that are affixed to the building structure and wherein at least one of the connector assemblies includes amore » flexible portion; one or more connector pockets disposed in the body portion the pockets capable of receiving at least a portion of the connector assembly.« less

Thin film photovoltaic device and process of manufacture

DOEpatents

Albright, S.P.; Chamberlin, R.

1997-10-07

Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells. 13 figs.

Thin film photovoltaic device and process of manufacture

DOEpatents

Albright, Scot P.; Chamberlin, Rhodes

1999-02-09

Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells.

Thin film photovoltaic device and process of manufacture

DOEpatents

Albright, S.P.; Chamberlin, R.

1999-02-09

Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells. 13 figs.

Thin film photovoltaic device and process of manufacture

DOEpatents

Albright, Scot P.; Chamberlin, Rhodes

1997-10-07

Provided is a thin film photovoltaic device and a method of manufacturing the device. The thin film photovoltaic device comprises a film layer having particles which are smaller than about 30 microns in size held in an electrically insulating matrix material to reduce the potential for electrical shorting through the film layer. The film layer may be provided by depositing preformed particles onto a surrogate substrate and binding the particles in a film-forming matrix material to form a flexible sheet with the film layer. The flexible sheet may be separated from the surrogate substrate and cut into flexible strips. A plurality of the flexible strips may be located adjacent to and supported by a common supporting substrate to form a photovoltaic module having a plurality of electrically interconnected photovoltaic cells.

Silicon solar photovoltaic power stations

NASA Technical Reports Server (NTRS)

Chowaniec, C. R.; Ferber, R. R.; Pittman, P. F.; Marshall, B. W.

1977-01-01

Modular design of components and arrays, cost estimates for modules and support structures, and cost/performance analysis of a central solar photovoltaic power plant are discussed. Costs of collector/reflector arrays are judged the dominant element in the total capital investment. High-concentration solar tracking arrays are recommended as the most economic means for producing solar photovoltaic energy when solar cells costs are high ($500 per kW generated). Capital costs for power conditioning subsystem components are itemized and system busbar energy costs are discussed at length.

Comparative PV LCOE calculator | Photovoltaic Research | NREL

Science.gov Websites

Use the Comparative Photovoltaic Levelized Cost of Energy Calculator (Comparative PV LCOE Calculator) to calculate levelized cost of energy (LCOE) for photovoltaic (PV) systems based on cost effect on LCOE to determine whether a proposed technology is cost-effective, perform trade-off analysis

Photovoltaics: A Solar Technology for Powering Tomorrow.

ERIC Educational Resources Information Center

Flavin, Christopher

1983-01-01

Photovoltaics, the technology that converts sunlight directly into electricity, may soon be a reliable power source for the world's poor. The one major challenge is cost reduction. Many topics are discussed, including solar powering the Third World, designing the solar building, investing in the sun, and the future of photovoltaics. (NW)

Photovoltaic power system for a lunar base

NASA Astrophysics Data System (ADS)

Karia, Kris

An assessment is provided of the viability of using photovoltaic power technology for lunar base application during the initial phase of the mission. The initial user power demands were assumed to be 25 kW (daytime) and 12.5 kW (night time). The effect of lunar adverse environmental conditions were also considered in deriving the photovoltaic power system concept. The solar cell array was found to impose no more design constraints than those solar arrays currently being designed for spacecraft and the Space Station Freedom. The long lunar night and the need to store sufficient energy to sustain a lunar facility during this period was found to be a major design driver. A photovoltaic power system concept was derived using high efficiency thin GaAs solar cells on a deployable flexible Kapton blanket. The solar array design was sized to generate sufficient power for daytime use and for a regenerative fuel cell (RFC) energy storage system to provide power during the night. Solar array sun-tracking is also proposed to maximize the array power output capability. The system launch mass was estimated to be approximately 10 metric tons. For mission application of photovoltaic technology other issues have to be addressed including the constraints imposed by launch vehicle, safety, and cost. For the initial phase of the mission a photovoltaic power system offers a safe option.

Fullerene derivatives as electron acceptors for organic photovoltaic cells.

PubMed

Mi, Dongbo; Kim, Ji-Hoon; Kim, Hee Un; Xu, Fei; Hwang, Do-Hoon

2014-02-01

Energy is currently one of the most important problems humankind faces. Depletion of traditional energy sources such as coal and oil results in the need to develop new ways to create, transport, and store electricity. In this regard, the sun, which can be considered as a giant nuclear fusion reactor, represents the most powerful source of energy available in our solar system. For photovoltaic cells to gain widespread acceptance as a source of clean and renewable energy, the cost per watt of solar energy must be decreased. Organic photovoltaic cells, developed in the past two decades, have potential as alternatives to traditional inorganic semiconductor photovoltaic cells, which suffer from high environmental pollution and energy consumption during production. Organic photovoltaic cells are composed of a blended film of a conjugated-polymer donor and a soluble fullerene-derivative acceptor sandwiched between a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-coated indium tin oxide positive electrode and a low-work-function metal negative electrode. Considerable research efforts aim at designing and synthesizing novel fullerene derivatives as electron acceptors with up-raised lowest unoccupied molecular orbital energy, better light-harvesting properties, higher electron mobility, and better miscibility with the polymer donor for improving the power conversion efficiency of the organic photovoltaic cells. In this paper, we systematically review novel fullerene acceptors synthesized through chemical modification for enhancing the photovoltaic performance by increasing open-circuit voltage, short-circuit current, and fill factor, which determine the performance of organic photovoltaic cells.

Charging a Capacitor with a Photovoltaic Module

ERIC Educational Resources Information Center

Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco; Navarro, Luis Barba

2017-01-01

Charging a capacitor with a photovoltaic module is an experiment which reveals a lot about the modules characteristics. It is customary to represent these characteristics with an equivalent circuit whose elements represent its physical parameters. The behavior of a photovoltaic module is very similar to that of a single cell but the electric…

The Harvard organic photovoltaic dataset

DOE PAGES

Lopez, Steven A.; Pyzer-Knapp, Edward O.; Simm, Gregor N.; ...

2016-09-27

Presented in this work is the Harvard Organic Photovoltaic Dataset (HOPV15), a collation of experimental photovoltaic data from the literature, and corresponding quantum-chemical calculations performed over a range of conformers, each with quantum chemical results using a variety of density functionals and basis sets. It is anticipated that this dataset will be of use in both relating electronic structure calculations to experimental observations through the generation of calibration schemes, as well as for the creation of new semi-empirical methods and the benchmarking of current and future model chemistries for organic electronic applications.

Recycling Of Cis Photovoltaic Waste

DOEpatents

Drinkard, Jr., William F.; Long, Mark O.; Goozner; Robert E.

1998-07-14

A method for extracting and reclaiming metals from scrap CIS photovoltaic cells and associated photovoltaic manufacturing waste by leaching the waste with dilute nitric acid, skimming any plastic material from the top of the leaching solution, separating glass substrate from the leachate, electrolyzing the leachate to plate a copper and selenium metal mixture onto a first cathode, replacing the cathode with a second cathode, re-electrolyzing the leachate to plate cadmium onto the second cathode, separating the copper from selenium, and evaporating the depleted leachate to yield a zinc and indium containing solid.

The Harvard organic photovoltaic dataset.

PubMed

Lopez, Steven A; Pyzer-Knapp, Edward O; Simm, Gregor N; Lutzow, Trevor; Li, Kewei; Seress, Laszlo R; Hachmann, Johannes; Aspuru-Guzik, Alán

2016-09-27

The Harvard Organic Photovoltaic Dataset (HOPV15) presented in this work is a collation of experimental photovoltaic data from the literature, and corresponding quantum-chemical calculations performed over a range of conformers, each with quantum chemical results using a variety of density functionals and basis sets. It is anticipated that this dataset will be of use in both relating electronic structure calculations to experimental observations through the generation of calibration schemes, as well as for the creation of new semi-empirical methods and the benchmarking of current and future model chemistries for organic electronic applications.

Proceedings of the 15th Space Photovoltaic Research and Technology Conference

NASA Technical Reports Server (NTRS)

Bailey, Sheila (Compiler)

2004-01-01

Reports from the 15th Space Photovoltaic Research and Technology Conference included topics on space solar cell research, space photovoltaics, multibandgap cells,thermophotovoltaics,flight experiments, environmental effects; calibration and characterization; and photovoltaics for planetary surfaces.

Sun-to-Wheels Exergy Efficiencies for Bio-Ethanol and Photovoltaics.

PubMed

Williams, Eric; Sekar, Ashok; Matteson, Schuyler; Rittmann, Bruce E

2015-06-02

The two main paths to power vehicles with sunlight are to use photosynthesis to grow biomass, converting to a liquid fuel for an internal combustion engine or to generate photovoltaic electricity that powers the battery of an electric vehicle. While the environmental attributes of these two paths have been much analyzed, prior studies consider the current state of technology. Technologies for biofuel and photovoltaic paths are evolving; it is critical to consider how progress might improve environmental performance. We address this challenge by assessing the current and maximum theoretical exergy efficiencies of bioethanol and photovoltaic sun-to-wheels process chains. The maximum theoretical efficiency is an upper bound stipulated by physical laws. The current net efficiency to produce motive power from silicon photovoltaic modules is estimated at 5.4%, much higher than 0.03% efficiency for corn-based ethanol. Flat-plate photovoltaic panels also have a much higher theoretical maximum efficiency than a C4 crop plant, 48% versus 0.19%. Photovoltaic-based power will always be vastly more efficient than a terrestrial crop biofuel. Providing all mobility in the U.S. via crop biofuels would require 130% of arable land with current technology and 20% in the thermodynamic limit. Comparable values for photovoltaic-based power are 0.7% and 0.081%, respectively.

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.

Photovoltaic venture analysis. Final report. Volume I. Executive summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Costello, D.; Posner, D.; Schiffel, D.

1978-07-01

The objective of the study, government programs under investigation, and a brief review of the approach are presented. Potential markets for photovoltaic systems relevant to the study are described. The response of the photovoltaic supply industry is then considered. A model which integrates the supply and demand characteristics of photovoltaics over time was developed. This model also calculates the economic benefits associated with various government subsidy programs. Results are derived under alternative possible supply, demand, and macroeconomic conditions. A probabilistic analysis of the costs and benefits of a $380 million federal photovoltaic procurement initiative, as well as certain alternative strategies,more » is summarized. Conclusions and recommendations based on the analysis are presented.« less

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.

Photovoltaic module with light reflecting backskin

DOEpatents

Gonsiorawski, Ronald C [Danvers, MA

2007-07-03

A photovoltaic module comprises electrically interconnected and mutually spaced photovoltaic cells that are encapsulated by a light-transmitting encapsulant between a light-transparent front cover and a back cover, with the back cover sheet being an ionomer/nylon alloy embossed with V-shaped grooves running in at least two directions and coated with a light reflecting medium so as to provide light-reflecting facets that are aligned with the spaces between adjacent cells and oriented so as to reflect light falling in those spaces back toward said transparent front cover for further internal reflection onto the solar cells, whereby substantially all of the reflected light will be internally reflected from said cover sheet back to the photovoltaic cells, thereby increasing the current output of the module. The internal reflector improves power output by as much as 67%.

Brief review of emerging photovoltaic absorbers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zakutayev, Andriy

Photovoltaic solar cells have recently made significant commercial progress and are on track toward meeting more than 1% of global energy demand. However, further research is needed on photovoltaic technologies that face no scalability constraints in generating more than 10% of the world's electricity. This 2017 article briefly reviews emerging photovoltaic absorber materials, focusing on research progress over the past 2-3 years. Particular emphasis is given to emerging solar cell absorbers -- for example, SnS, Sb 2Se 3, Cu 2SnS 3, and CuSbSe 2 -- related to established solar cell technologies such as CdTe, Cu(In,Ga)Se 2, and CH 3NH 3PbImore » 3. Lastly, the general publication and performance trends are discussed, and the promising future research directions are pointed out.« less

Brief review of emerging photovoltaic absorbers

DOE PAGES

Zakutayev, Andriy

2017-02-08

Photovoltaic solar cells have recently made significant commercial progress and are on track toward meeting more than 1% of global energy demand. However, further research is needed on photovoltaic technologies that face no scalability constraints in generating more than 10% of the world's electricity. This 2017 article briefly reviews emerging photovoltaic absorber materials, focusing on research progress over the past 2-3 years. Particular emphasis is given to emerging solar cell absorbers -- for example, SnS, Sb 2Se 3, Cu 2SnS 3, and CuSbSe 2 -- related to established solar cell technologies such as CdTe, Cu(In,Ga)Se 2, and CH 3NH 3PbImore » 3. Lastly, the general publication and performance trends are discussed, and the promising future research directions are pointed out.« less

Inaugural History of the National Center for Photovoltaics | Photovoltaic

Science.gov Websites

technology and disseminating information about photovoltaics (PV) in the United States. When created, the NCPV's long-term goals were for PV modules and systems to reach still higher efficiencies with improved , industry, and other federal programs into a united effort and accelerating the advance of PV as an industry

19 CFR 123.13 - Foreign repairs to domestic locomotives and other domestic railroad equipment.

Code of Federal Regulations, 2010 CFR

2010-04-01

... domestic railroad equipment. 123.13 Section 123.13 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... International Traffic § 123.13 Foreign repairs to domestic locomotives and other domestic railroad equipment. A report of the first arrival in the United States of a domestic locomotive or other railroad equipment...

Environmental requirements for flat plate photovoltaic modules for terrestrial applications

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Ross, R. G., Jr.

1979-01-01

The environmental test requirements that have been developed for flat plate modules purchased through Department of Energy funding are described. Concurrent with the selection of the initial qualification tests from space program experience - temperature cycling and humidity - surveys of existing photovoltaic systems in the field revealed that arrays were experiencing the following failure modes: interconnect breakage, delamination, and electrical termination corrosion. These coupled with application-dependent considerations led to the development of additional qualification tests, such as cyclic pressure loading, warped mounting surface, and hail. Rationale for the selection of tests, their levels and durations is described. Comparisons between field-observed degradation and test-induced degradation show a positive correlation with some of the observed field effects. Also, the tests are proving useful for detecting design, process, and workmanship deficiencies. The status of study efforts for the development of environmental requirements for field-related problems is reviewed.

The status of photovoltaic concentrator development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maish, A. B.

1992-10-01

Several companies in the United States are actively pursuing the commercialization of photovoltaic concentrator technology. Under the auspices of the US Department of Energy`s Concentrator Initiative, the Electric Power Research Institute`s High Concentration Photovoltaic Program and several privately funded programs, these companies are developing a range of designs from low-concentration linear-focus to high-concentration point-focus cells and collectors. Design details and status of each development program is presented.

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.

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.

Photovoltaic application for disaster relief

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, W.R. Jr.

1995-11-01

Hurricanes, floods, tornados, and earthquakes are natural disasters that can happen at any time destroying homes, businesses, and natural surroundings. One such disaster, Hurricane Andrew, devastated South Florida leaving several hundred-thousand people homeless. Many people were without electrical service, functioning water and sewage systems, communications, and medical services for days, even weeks in the aftermath of the storm. Emergency management teams, the military, and countless public and private organizations staged a massive relief effort. Dependency on electrical utility power became a pronounced problem as emergency services were rendered to survivors and the rebuilding process started. Many of the energy needsmore » of emergency management organizations, relief workers, and the general public can be satisfied with solar electric energy systems. Photovoltaic (PV) power generated from solar energy is quiet, safe, inexhaustible and pollution-free. Previously, photovoltaics have supplied emergency power for Hurricanes Hugo and Andrew, and the earthquake at Northridge in Southern California. This document focuses on photovoltaic technology and its application to disaster relief efforts.« less

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.

Mechanistic insights into the photoinduced charge carrier dynamics of BiOBr/CdS nanosheet heterojunctions for photovoltaic application.

PubMed

Jia, Huimin; Zhang, Beibei; He, Weiwei; Xiang, Yong; Zheng, Zhi

2017-03-02

The rational design of high performance hetero-structure photovoltaic devices requires a full understanding of the photoinduced charge transfer mechanism and kinetics at the interface of heterojunctions. In this paper, we intelligently fabricated p-BiOBr/n-CdS heterojunctions with perfect nanosheet arrays by using a facile successive ionic layer adsorption and reaction and chemical bath deposition methods at low temperature. A BiOBr/CdS heterojunction based solar cell has been fabricated which exhibited enhanced photovoltaic responses. Assisted by the surface photovoltage (SPV), transient photovoltage (TPV) and Kelvin probe technique, the photoinduced charge transfer dynamics on the BiOBr nanosheet and p-BiOBr/n-CdS interface were systematically investigated. It was found that the BiOBr/CdS nanosheet array heterojunctions were more efficient in facilitating charge carrier separation than both bare BiOBr and CdS films. The mechanism underlying the photoinduced charge carrier transfer behaviour was unravelled by allying the energy band of BiOBr/CdS p-n junctions from both the interfacial electric field and surface electric field. In addition, the CdS loading thickness in the p-BiOBr/n-CdS heterojunction and the incident wavelength affected greatly the transfer behavior of photoinduced charges, which was of great value for design of photovoltaic devices.

Photovoltaic-system evaluation at the Northeast Residential Experiment Station

NASA Astrophysics Data System (ADS)

Russell, M. C.

1983-01-01

Five residential photovoltaic systems were tested and the systems' performance and cost was evaluated. The five systems each consist of an unoccupied structure employing a roof mounted photovoltaic array and a utility connected power inverter capable of sending excess PV generated energy to the local utility system. The photovoltaic systems are designed to meet at least 50% of the total annual electrical demand of residences in the cold climate regions of the country. The following specific issues were investigated: photovoltaic array and inverter system power rating and performance characterization, system energy production, reliability and system cost/worth. Summary load data from five houses in the vicinity of the Northeast Residential Experiment Station, and meteorological data from the station's weather station are also presented.

A water-budget approach to estimating potential groundwater recharge from two domestic sewage disposal fields in eastern Bernalillo County, New Mexico, 2011-12

USGS Publications Warehouse

Crilley, Dianna M.; Collison, Jake W.

2015-08-04

During this study, the disposal fields at sites A and B received a measured volume of effluent from two-person domestic residences equipped with an onsite low-pressure dosing system. A combined evapotranspiration measurement and modeling technique was used to estimate the amount of evapotranspirative loss from the disposal field and from the surrounding terrain. A portable hemispherical flux chamber was used to measure evapotranspiration at fixed locations on the disposal fields and on the surrounding terrain at sites A and B. Data from hemispherical flux chamber measurements were used to calibrate a Penman-Monteith modeled evapotranspiration rate on the disposal field and on the surrounding terrain at site A from January 1, 2011, to December 31, 2011, and from January 1, 2012, to December 31, 2012, and at site B from January 1, 2011, to December 31, 2011. Micrometeorological and soil data from instrumentation on the disposal fields and on the surrounding terrain at sites A and B were used as input data into the Penman-Monteith equation. The mean potential recharge from disposal field effluent during 2011–12 at sites A and B was 63 percent of the volume of effluent dosed to the disposal field.

Laterally inherently thin amorphous-crystalline silicon heterojunction photovoltaic cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, Zahidur R., E-mail: zr.chowdhury@utoronto.ca; Kherani, Nazir P., E-mail: kherani@ecf.utoronto.ca

2014-12-29

This article reports on an amorphous-crystalline silicon heterojunction photovoltaic cell concept wherein the heterojunction regions are laterally narrow and distributed amidst a backdrop of well-passivated crystalline silicon surface. The localized amorphous-crystalline silicon heterojunctions consisting of the laterally thin emitter and back-surface field regions are precisely aligned under the metal grid-lines and bus-bars while the remaining crystalline silicon surface is passivated using the recently proposed facile grown native oxide–plasma enhanced chemical vapour deposited silicon nitride passivation scheme. The proposed cell concept mitigates parasitic optical absorption losses by relegating amorphous silicon to beneath the shadowed metallized regions and by using optically transparentmore » passivation layer. A photovoltaic conversion efficiency of 13.6% is obtained for an untextured proof-of-concept cell illuminated under AM 1.5 global spectrum; the specific cell performance parameters are V{sub OC} of 666 mV, J{sub SC} of 29.5 mA-cm{sup −2}, and fill-factor of 69.3%. Reduced parasitic absorption, predominantly in the shorter wavelength range, is confirmed with external quantum efficiency measurement.« less

Engineered Emitters for Improved Silicon Photovoltaics

NASA Astrophysics Data System (ADS)

Kamat, Ronak A.

In 2014, installation of 5.3GW of new Photovoltaic (PV) systems occurred in the United States, raising the total installed capacity to 16.36GW. Strong growth is predicted for the domestic PV market with analysts reporting goals of 696GW by 2020. Conventional single crystalline silicon cells are the technology of choice, accounting for 90% of the installations in the global commercial market. Cells made of GaAs offer higher efficiencies, but at a substantially higher cost. Thin film technologies such as CIGS and CdTe compete favorably with multi-crystalline Si (u-Si), but at 20% efficiency, still lag the c-Si cell in performance. The c-Si cell can be fabricated to operate at approximately 25% efficiency, but commercially the efficiencies are in the 18-21% range, which is a direct result of cost trade-offs between process complexity and rapid throughput. With the current cost of c-Si cell modules at nearly 0.60/W. The technology is well below the historic metric of 1/W for economic viability. The result is that more complex processes, once cost-prohibitive, may now be viable. An example is Panasonic's HIT cell which operates in the 22-24% efficiency range. To facilitate research and development of novel PV materials and techniques, RIT has developed a basic solar cell fabrication process. Student projects prior to this work had produced cells with 12.8% efficiency using p type substrates. This thesis reports on recent work to improve cell efficiencies while simultaneously expanding the capability of the rapid prototyping process. In addition to the p-Si substrates, cells have been produced using n-Si substrates. The cell emitter, which is often done with a single diffusion or implant has been re-engineered using a dual implant of the same dose. This dual-implanted emitter has been shown to lower contact resistance, increase Voc, and increase the efficiency. A p-Si substrate cell has been fabricated with an efficiency of 14.6% and n-Si substrate cell with a 13

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 photovoltaicmore » 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.« less

Domestic and Domesticating Education in the Late Victorian City

ERIC Educational Resources Information Center

Heggie, Vanessa

2011-01-01

This article explores the various types of domestic education, particularly cookery, available in Manchester between 1870 and 1902. The work of the two local School Boards and the Manchester School of Domestic Economy are shown as part of a complicated network of provision--a mixed economy of welfare, including enthusiastic philanthropists and…

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.

Aternating current photovoltaic building block

DOEpatents

Bower, Ward Issac; Thomas, Michael G.; Ruby, Douglas S.

2004-06-15

A modular apparatus for and method of alternating current photovoltaic power generation comprising via a photovoltaic module, generating power in the form of direct current; and converting direct current to alternating current and exporting power via one or more power conversion and transfer units attached to the module, each unit comprising a unitary housing extending a length or width of the module, which housing comprises: contact means for receiving direct current from the module; one or more direct current-to-alternating current inverters; an alternating current bus; and contact means for receiving alternating current from the one or more inverters.

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.

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.

The Harvard organic photovoltaic dataset

PubMed Central

Lopez, Steven A.; Pyzer-Knapp, Edward O.; Simm, Gregor N.; Lutzow, Trevor; Li, Kewei; Seress, Laszlo R.; Hachmann, Johannes; Aspuru-Guzik, Alán

2016-01-01

The Harvard Organic Photovoltaic Dataset (HOPV15) presented in this work is a collation of experimental photovoltaic data from the literature, and corresponding quantum-chemical calculations performed over a range of conformers, each with quantum chemical results using a variety of density functionals and basis sets. It is anticipated that this dataset will be of use in both relating electronic structure calculations to experimental observations through the generation of calibration schemes, as well as for the creation of new semi-empirical methods and the benchmarking of current and future model chemistries for organic electronic applications. PMID:27676312

High-resolution global irradiance monitoring from photovoltaic systems

NASA Astrophysics Data System (ADS)

Buchmann, Tina; Pfeilsticker, Klaus; Siegmund, Alexander; Meilinger, Stefanie; Mayer, Bernhard; Pinitz, Sven; Steinbrecht, Wolfgang

2016-04-01

Reliable and regional differentiated power forecasts are required to guarantee an efficient and economic energy transition towards renewable energies. Amongst other renewable energy technologies, e.g. wind mills, photovoltaic systems are an essential component of this transition being cost-efficient and simply to install. Reliable power forecasts are however required for a grid integration of photovoltaic systems, which among other data requires high-resolution spatio-temporal global irradiance data. Hence the generation of robust reviewed global irradiance data is an essential contribution for the energy transition. To achieve this goal our studies introduce a novel method which makes use of photovoltaic power generation in order to infer global irradiance. The method allows to determine high-resolution temporal global irradiance data (one data point every 15 minutes at each location) from power data of operated photovoltaic systems. Due to the multitude of installed photovoltaic systems (in Germany) the detailed spatial coverage is much better than for example only using global irradiance data from conventional pyranometer networks (e.g. from the German Weather Service). Our designated method is composed of two components: a forward component, i.e. to conclude from predicted global irradiance to photovoltaic (PV) power, and a backward component, i.e. from PV power with suitable calibration to global irradiance. The forward process is modelled by using the radiation transport model libRadtran (B. Mayer and A. Kylling (1)) for clear skies to obtain the characteristics (orientation, size, temperature dependence, …) of individual PV systems. For PV systems in the vicinity of a meteorological station, these data are validated against calibrated pyranometer readings. The forward-modelled global irradiance is used to determine the power efficiency for each photovoltaic system using non-linear optimisation techniques. The backward component uses the power efficiency

The Experiential Learning Impact of International and Domestic Study Tours: Class Excursions That Are More than Field Trips

ERIC Educational Resources Information Center

Gomez-Lanier, Lilia

2017-01-01

Experiential education programs, such as international and domestic study tours, bridge the limitations of formal learning classroom by allowing students to experience reality in a new learning dimension. This mixed-methods study explores experiential learning during a domestic interior design study tour to New York City and an international…

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.

76 FR 78313 - Crystalline Silicon Photovoltaic Cells and Modules From China

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-16

...)] Crystalline Silicon Photovoltaic Cells and Modules From China Determinations On the basis of the record \\1... injured by reason of imports from China of crystalline silicon photovoltaic cells and modules, provided... imports of crystalline silicon photovoltaic cells and modules from China. Accordingly, effective October...

Acenes, Heteroacenes and Analogous Molecules for Organic Photovoltaic and Field Effect Transistor Applications

NASA Astrophysics Data System (ADS)

Granger, Devin Benjamin

donor molecules for bulk heterojunction organic photovoltaics based on anthrathiophene and benzo[1,2-b:4,5-b']dithiophene central units like literature molecules containing fluorene and dithieno[2,3-b:2',3'-d]silole cores. The synthetic strategies of developing reduced symmetry benzo[1,2-b:4,5-b']dithiophene to study the effect of substitution around the central unit is also described. The optical and electronic properties of the donors and acceptors are described along with the performance and characteristics of devices employing these molecules. The final two data chapters focus on new nitrogen containing polycyclic hydrocarbons containing indolizine and (2.2.2) cyclazine units. The optical, electronic and other physical properties of these molecules are explored, in addition to the synthetic strategies for incorporating the indolizine and cyclazine units. By use of alkylsilylethynyl groups, crystal engineering was investigated for the benzo[2,3-b:5,6-b']diindolizine chromophore described in chapter 4 to target the 2-D "brick-work" packing motif for application in field effect transistor devices. Optical and electronic properties of the cyclazine end-capped acene molecules described in chapter 5 were investigated and described in relation to the base acene molecules. In both cases, density functional theory calculations were conducted to better understand unexpected optical properties of these molecules, which are like the linear acene series despite the non-linear attachment.

Molecular Epidemiology of Salmonella enterica Serovar Typhimurium Isolates Determined by Pulsed-Field Gel Electrophoresis: Comparison of Isolates from Avian Wildlife, Domestic Animals, and the Environment in Norway

PubMed Central

Refsum, Thorbjørn; Heir, Even; Kapperud, Georg; Vardund, Traute; Holstad, Gudmund

2002-01-01

The molecular epidemiology of 142 isolates of Salmonella enterica serovar Typhimurium from avian wildlife, domestic animals, and the environment in Norway was investigated using pulsed-field gel electrophoresis (PFGE) and computerized numerical analysis of the data. The bacterial isolates comprised 79 isolates from wild-living birds, including 46 small passerines and 26 gulls, and 63 isolates of nonavian origin, including 50 domestic animals and 13 environmental samples. Thirteen main clusters were discernible at the 90% similarity level. Most of the isolates (83%) were grouped into three main clusters. These were further divided into 20 subclusters at the 95% similarity level. Isolates from passerines, gulls, and pigeons dominated within five subclusters, whereas isolates from domestic animals and the environment belonged to many different subclusters with no predominance. The results support earlier results that passerines constitute an important source of infection to humans in Norway, whereas it is suggested that gulls and pigeons, based on PFGE analysis, represent only a minor source of human serovar Typhimurium infections. Passerines, gulls, and pigeons may also constitute a source of infection of domestic animals and feed plants or vice versa. Three isolates from cattle and a grain source, of which two were multiresistant, were confirmed as serovar Typhimurium phage type DT 104. These represent the first reported phage type DT 104 isolates from other sources than humans in Norway. PMID:12406755

Potential environmental hazards of photovoltaic panel disposal: Discussion of Tammaro et al. (2015).

PubMed

Sinha, Parikhit

2017-02-05

In their recent publication in Journal of Hazardous Materials (http://dx.doi.org/10.1016/j.jhazmat.2015.12.018), Tammaro et al. evaluate the potential environmental impacts of an illegal disposal scenario of photovoltaic panels in the European Union. Critical assumptions that underlie the study's conclusions would benefit from clarification. A scenario of photovoltaic panels finely crushed and abandoned in nature is not supported with field breakage data, in which photovoltaic panels remain largely intact with a number of glass fractures or cracks, as opposed to breakage into cm-scale pieces. Fate and transport analysis is necessary to evaluate how leachate transforms and disperses in moving from the point of emissions to the point of exposure, prior to making comparisons with drinking water limits. Some hazardous metal content has declined in both crystalline silicon and thin film panels, including a 50% decline in semiconductor material intensity in CdTe thin film panels (g CdTe/W) from 2009 to 2015. Waste laws, recycling requirements and minimum treatment standards under the EU WEEE Directive, and illegal disposal rates affect the accuracy of forecasts of releasable metal amounts from PV panels in Europe through 2050. Copyright © 2016 Elsevier B.V. All rights reserved.

Exceeding Conventional Photovoltaic Efficiency Limits Using Colloidal Quantum Dots

NASA Astrophysics Data System (ADS)

Pach, Gregory F.

Colloidal quantum dots (QDs) are a widely investigated field of research due to their highly tunable nature in which the optical and electronic properties of the nanocrystal can be manipulated by merely changing the nanocrystal's size. Specifically, colloidal quantum dot solar cells (QDSCs) have become a promising candidate for future generation photovoltaic technology. Quantum dots exhibit multiple exciton generation (MEG) in which multiple electron-hole pairs are generated from a single high-energy photon. This process is not observed in bulk-like semiconductors and allows for QDSCs to achieve theoretical efficiency limits above the standard single-junction Shockley-Queisser limit. However, the fast expanding field of QDSC research has lacked standardization of synthetic techniques and device design. Therefore, we sought to detail methodology for synthesizing PbS and PbSe QDs as well as photovoltaic device fabrication techniques as a fast track toward constructing high-performance solar cells. We show that these protocols lead toward consistently achieving efficiencies above 8% for PbS QDSCs. Using the same methodology for building single-junction photovoltaic devices, we incorporated PbS QDs as a bottom cell into a monolithic tandem architecture along with solution-processed CdTe nanocrystals. Modeling shows that near-peak tandem device efficiencies can be achieved across a wide range of bottom cell band gaps, and therefore the highly tunable band gap of lead-chalcogenide QDs lends well towards a bottom cell in a tandem architecture. A fully functioning monolithic tandem device is realized through the development of a ZnTe/ZnO recombination layer that appropriately combines the two subcells in series. Multiple recent reports have shown nanocrystalline heterostructures to undergo the MEG process more efficiency than several other nanostrucutres, namely lead-chalcogenide QDs. The final section of my thesis expands upon a recent publication by Zhang et. al., which

77 FR 72884 - Crystalline Silicon Photovoltaic Cells and Modules From China

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-06

... Silicon Photovoltaic Cells and Modules From China Determinations On the basis of the record \\1\\ developed... imports of crystalline silicon photovoltaic cells and modules from China, provided for in subheadings 8501... silicon photovoltaic cells and modules from China. Chairman Irving A. Williamson and Commissioner Dean A...

Molecular Design of Benzodithiophene-Based Organic Photovoltaic Materials.

PubMed

Yao, Huifeng; Ye, Long; Zhang, Hao; Li, Sunsun; Zhang, Shaoqing; Hou, Jianhui

2016-06-22

Advances in the design and application of highly efficient conjugated polymers and small molecules over the past years have enabled the rapid progress in the development of organic photovoltaic (OPV) technology as a promising alternative to conventional solar cells. Among the numerous OPV materials, benzodithiophene (BDT)-based polymers and small molecules have come to the fore in achieving outstanding power conversion efficiency (PCE) and breaking 10% efficiency barrier in the single junction OPV devices. Remarkably, the OPV device featured by BDT-based polymer has recently demonstrated an impressive PCE of 11.21%, indicating the great potential of this class of materials in commercial photovoltaic applications. In this review, we offered an overview of the organic photovoltaic materials based on BDT from the aspects of backbones, functional groups, alkyl chains, and device performance, trying to provide a guideline about the structure-performance relationship. We believe more exciting BDT-based photovoltaic materials and devices will be developed in the near future.

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.

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.

Solar photovoltaic power systems: an electric utility R & d perspective.

PubMed

Demeo, E A; Taylor, R W

1984-04-20

Solar photovoltaic technology is receiving increasing attention as a prospective source of bulk, electric utility power within the next 10 to 20 years. Successful development will require solar energy conversion efficiencies of about 15 percent for photovoltaic flat-plate modules, or about 25 percent for photovoltaic cells using highly concentrated sunlight. Three different cell technologies have a better than even chance of achieving these target efficiencies with costs and operating lifetimes that would allow significant use by electric utilities. The challenge for the next decade is to push photovoltaic technology to its physical limits while expanding markets and user confidence with currently available systems.

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.

Observation of surface dark photovoltaic solitons.

PubMed

Yang, Xi; Chen, Weiqiang; Yao, Peng; Zhang, Tianhao; Tian, Jianguo; Xu, Jingjun

2013-02-25

Surface dark solitons in photovoltaic nonlinear media are reported. Taking advantage of diffusion and photovoltaic nonlinearities we demonstrated the surface dark solitons and their behaviors near surface theoretically and experimentally in LiNbO₃ crystal. It is very interesting that surface dark soliton is just half of dark soliton in bulk. Another interesting thing is that transverse modulation instability can be perfectly suppressed by surface dark soliton in virtue of surface. In addition, surface waveguides were written successfully utilizing surface dark soliton.

Catalyst-free, III-V nanowire photovoltaics

NASA Astrophysics Data System (ADS)

Davies, D. G.; Lambert, N.; Fry, P. W.; Foster, A.; Krysa, A. B.; Wilson, L. R.

2014-05-01

We report on room temperature, photovoltaic operation of catalyst-free GaAs p-i-n junction nanowire arrays. Growth studies were first performed to determine the optimum conditions for controlling the vertical and lateral growth of the nanowires. Following this, devices consisting of axial p-i-n junctions were fabricated by planarising the nanowire arrays with a hard baked polymer. We discuss the photovoltaic properties of this proof-of-concept device, and significant improvements to be made during the growth.

One-dimensional zinc oxide nanomaterials synthesis and photovoltaic applications

NASA Astrophysics Data System (ADS)

Weintraub, Benjamin A.

As humanly engineered materials systems approach the atomic scale, top-down manufacturing approaches breakdown and following nature's example, bottom-up or self-assembly methods have the potential to emerge as the dominant paradigm. Synthesis of one-dimensional nanomaterials takes advantage of such self-assembly manufacturing techniques, but until now most efforts have relied on high temperature vapor phase schemes which are limited in scalability and compatibility with organic materials. The solution-phase approach is an attractive low temperature alternative to overcome these shortcomings. To this end, this thesis is a study of the rationale solution-phase synthesis of ZnO nanowires and applications in photovoltaics. The following thesis goals have been achieved: rationale synthesis of a single ZnO nanowire on a polymer substrate without seeding, design of a wafer-scale technique to control ZnO nanowire array density using layer-by-layer polymers, determination of optimal nanowire field emitter density to maximize the field enhancement factor, design of bridged nanowires across metal electrodes to order to circumvent post-synthesis manipulation steps, electrical characterization of bridged nanowires, rationale solution-phase synthesis of long ZnO nanowires on optical fibers, fabrication of ZnO nanowire dye-sensitized solar cells on optical fibers, electrical and optical characterization of solar cell devices, comparison studies of 2-D versus 3-D nanowire dye-sensitized solar cell devices, and achievement of 6-fold solar cell power conversion efficiency enhancement using a 3-D approach. The thesis results have implications in nanomanufacturing scale-up and next generation photovoltaics.

Photovoltaic and photoelectrochemical conversion of solar energy.

PubMed

Grätzel, Michael

2007-04-15

The Sun provides approximately 100,000 terawatts to the Earth which is about 10000 times more than the present rate of the world's present energy consumption. Photovoltaic cells are being increasingly used to tap into this huge resource and will play a key role in future sustainable energy systems. So far, solid-state junction devices, usually made of silicon, crystalline or amorphous, and profiting from the experience and material availability resulting from the semiconductor industry, have dominated photovoltaic solar energy converters. These systems have by now attained a mature state serving a rapidly growing market, expected to rise to 300 GW by 2030. However, the cost of photovoltaic electricity production is still too high to be competitive with nuclear or fossil energy. Thin film photovoltaic cells made of CuInSe or CdTe are being increasingly employed along with amorphous silicon. The recently discovered cells based on mesoscopic inorganic or organic semiconductors commonly referred to as 'bulk' junctions due to their three-dimensional structure are very attractive alternatives which offer the prospect of very low cost fabrication. The prototype of this family of devices is the dye-sensitized solar cell (DSC), which accomplishes the optical absorption and the charge separation processes by the association of a sensitizer as light-absorbing material with a wide band gap semiconductor of mesoporous or nanocrystalline morphology. Research is booming also in the area of third generation photovoltaic cells where multi-junction devices and a recent breakthrough concerning multiple carrier generation in quantum dot absorbers offer promising perspectives.

Comparative methylomics between domesticated and wild silkworms implies possible epigenetic influences on silkworm domestication

PubMed Central

2013-01-01

Background In contrast to wild species, which have typically evolved phenotypes over long periods of natural selection, domesticates rapidly gained human-preferred agronomic traits in a relatively short-time frame via artificial selection. Under domesticated conditions, many traits can be observed that cannot only be due to environmental alteration. In the case of silkworms, aside from genetic divergence, whether epigenetic divergence played a role in domestication is an unanswered question. The silkworm is still an enigma in that it has two DNA methyltransferases (DNMT1 and DNMT2) but their functionality is unknown. Even in particular the functionality of the widely distributed DNMT1 remains unknown in insects in general. Results By embryonic RNA interference, we reveal that knockdown of silkworm Dnmt1 caused decreased hatchability, providing the first direct experimental evidence of functional significance of insect Dnmt1. In the light of this fact and those that DNA methylation is correlated with gene expression in silkworms and some agronomic traits in domesticated organisms are not stable, we comprehensively compare silk gland methylomes of 3 domesticated (Bombyx mori) and 4 wild (Bombyx mandarina) silkworms to identify differentially methylated genes between the two. We observed 2-fold more differentiated methylated cytosinces (mCs) in domesticated silkworms as compared to their wild counterparts, suggesting a trend of increasing DNA methylation during domestication. Further study of more domesticated and wild silkworms narrowed down the domesticates’ epimutations, and we were able to identify a number of differential genes. One such gene showing demethyaltion in domesticates correspondently displays lower gene expression, and more interestingly, has experienced selective sweep. A methylation-increased gene seems to result in higher expression in domesticates and the function of its Drosophila homolog was previously found to be essential for cell volume

Design principles for shift current photovoltaics

DOE PAGES

Cook, Ashley M.; M. Fregoso, Benjamin; de Juan, Fernando; ...

2017-01-25

While the basic principles of conventional solar cells are well understood, little attention has gone towards maximizing the efficiency of photovoltaic devices based on shift currents. Furthermore, by analysing effective models, here we outline simple design principles for the optimization of shift currents for frequencies near the band gap. This method allows us to express the band edge shift current in terms of a few model parameters and to show it depends explicitly on wavefunctions in addition to standard band structure. We use our approach to identify two classes of shift current photovoltaics, ferroelectric polymer films and single-layer orthorhombic monochalcogenidesmore » such as GeS, which display the largest band edge responsivities reported so far. Moreover, exploring the parameter space of the tight-binding models that describe them we find photoresponsivities that can exceed 100 mA W -1 . Our results illustrate the great potential of shift current photovoltaics to compete with conventional solar cells.« less

Design principles for shift current photovoltaics

PubMed Central

Cook, Ashley M.; M. Fregoso, Benjamin; de Juan, Fernando; Coh, Sinisa; Moore, Joel E.

2017-01-01

While the basic principles of conventional solar cells are well understood, little attention has gone towards maximizing the efficiency of photovoltaic devices based on shift currents. By analysing effective models, here we outline simple design principles for the optimization of shift currents for frequencies near the band gap. Our method allows us to express the band edge shift current in terms of a few model parameters and to show it depends explicitly on wavefunctions in addition to standard band structure. We use our approach to identify two classes of shift current photovoltaics, ferroelectric polymer films and single-layer orthorhombic monochalcogenides such as GeS, which display the largest band edge responsivities reported so far. Moreover, exploring the parameter space of the tight-binding models that describe them we find photoresponsivities that can exceed 100 mA W−1. Our results illustrate the great potential of shift current photovoltaics to compete with conventional solar cells. PMID:28120823

Apparatus for encapsulating a photovoltaic module

DOEpatents

Albright, Scot P.; Dugan, Larry M.

1995-10-24

The subject inventions concern various photovoltaic module designs to protect the module from horizontal and vertical impacts and degradation of solar cell efficiency caused by moisture. In one design, a plurality of panel supports that are positioned adjacent to the upper panel in a photovoltaic module absorb vertical forces exerted along an axis perpendicular to the upper panel. Other designs employ layers of glass and tempered glass, respectively, to protect the module from vertical impacts. A plurality of button-shaped channels is used around the edges of the photovoltaic module to absorb forces applied to the module along an axis parallel to the module and direct moisture away from the module that could otherwise penetrate the module and adversely affect the cells within the module. A spacer is employed between the upper and lower panels that has a coefficient of thermal expansion substantially equivalent to the coefficient of thermal expansion of at least one of the panels.

Design principles for shift current photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Ashley M.; M. Fregoso, Benjamin; de Juan, Fernando

While the basic principles of conventional solar cells are well understood, little attention has gone towards maximizing the efficiency of photovoltaic devices based on shift currents. Furthermore, by analysing effective models, here we outline simple design principles for the optimization of shift currents for frequencies near the band gap. This method allows us to express the band edge shift current in terms of a few model parameters and to show it depends explicitly on wavefunctions in addition to standard band structure. We use our approach to identify two classes of shift current photovoltaics, ferroelectric polymer films and single-layer orthorhombic monochalcogenidesmore » such as GeS, which display the largest band edge responsivities reported so far. Moreover, exploring the parameter space of the tight-binding models that describe them we find photoresponsivities that can exceed 100 mA W -1 . Our results illustrate the great potential of shift current photovoltaics to compete with conventional solar cells.« less

Domestic Violence and Dependency Courts: The "Greenbook" Demonstration Experience

ERIC Educational Resources Information Center

Malik, Neena M.; Silverman, Jerry; Wang, Kathleen; Janczewski, Colleen

2008-01-01

This field study reports on a cross-site evaluation of dependency courts in communities receiving federal funding to implement the "Greenbook" initiative, a multisite demonstration for community improvement of coordinated responses to families victimized by domestic violence and child maltreatment. This article focuses on the dependency court,…

High-Efficiency Photovoltaic Energy Conversion using Surface Acoustic Waves in Piezoelectric Semiconductors

NASA Astrophysics Data System (ADS)

Yakovenko, Victor

2010-03-01

We propose a radically new design for photovoltaic energy conversion using surface acoustic waves (SAWs) in piezoelectric semiconductors. The periodically modulated electric field from SAW spatially separates photogenerated electrons and holes to the maxima and minima of SAW, thus preventing their recombination. The segregated electrons and holes are transported by the moving SAW to the collecting electrodes of two types, which produce dc electric output. Recent experiments [1] using SAWs in GaAs have demonstrated the photon to current conversion efficiency of 85%. These experiments were designed for photon counting, but we propose to adapt these techniques for highly efficient photovoltaic energy conversion. The advantages are that the electron-hole segregation takes place in the whole volume where SAW is present, and the electrons and holes are transported in the organized, collective manner at high speed, as opposed to random diffusion in conventional devices.[4pt] [1] S. J. Jiao, P. D. Batista, K. Biermann, R. Hey, and P. V. Santos, J. Appl. Phys. 106, 053708 (2009).

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.

18th Space Photovoltaic Research and Technology Conference

NASA Technical Reports Server (NTRS)

Morton, Thomas L. (Compiler)

2005-01-01

The 18th Space Photovoltaic Research and Technology (SPRAT XVIII) Conference was held September 16 to 18, 2003, at the Ohio Aerospace Institute (OAI) in Brook Park, 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 cell technology. This year s conference continued to build on many of the trends shown in SPRAT XVII-the continued advances of thin-film and multijunction solar cell technologies and the new issues required to qualify those types of cells for space applications.

Utility photovoltaic group: Status report

NASA Astrophysics Data System (ADS)

Serfass, Jeffrey A.; Hester, Stephen L.; Wills, Bethany N.

1996-01-01

The Utility PhotoVoltaic Group (UPVG) was formed in October of 1992 with a mission to accelerate the use of cost-effective small-scale and emerging grid-connected applications of photovoltaics for the benefit of electric utilities and their customers. The UPVG is now implementing a program to install up to 50 megawatts of photovoltaics in small-scale and grid-connected applications. This program, called TEAM-UP, is a partnership of the U.S. electric utility industry and the U.S. Department of Energy to help develop utility PV markets. TEAM-UP is a utility-directed program to significantly increase utility PV experience by promoting installations of utility PV systems. Two primary program areas are proposed for TEAM-UP: (1) Small-Scale Applications (SSA)—an initiative to aggregate utility purchases of small-scale, grid-independent applications; and (2) Grid-Connected Applications (GCA)—an initiative to identify and competitively award cost-sharing contracts for grid-connected PV systems with high market growth potential, or collective purchase programs involving multiple buyers. This paper describes these programs and outlines the schedule, the procurement status, and the results of the TEAM-UP process.

NASA photovoltaic research and technology

NASA Technical Reports Server (NTRS)

Flood, Dennis J.

1988-01-01

NASA photovoltaic R and D efforts address future Agency space mission needs through a comprehensive, integrated program. Activities range from fundamental studies of materials and devices to technology demonstrations of prototype hardware. The program aims to develop and apply an improved understanding of photovoltaic energy conversion devices and systems that will increase the performance, reduce the mass, and extend the lifetime of photovoltaic arrays for use in space. To that end, there are efforts aimed at improving cell efficiency, reducing the effects of space particulate radiation damage (primarily electrons and protons), developing ultralightweight cells, and developing advanced ray component technology for high efficiency concentrator arrays and high performance, ultralightweight arrays. Current goals that have been quantified for the program are to develop cell and array technology capable of achieving 300 watts/kg for future missions for which mass is a critical factor, or 300 watts/sq m for future missions for which array size is a major driver (i.e., Space Station). A third important goal is to develop cell and array technology which will survive the GEO space radiation environment for at least 10 years.

Social impact of the tangaye (upper volta) photovoltaic demostrtion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, A.F.

1983-06-01

The Tangaye (Upper Volta) Solar Energy Demonstration was implemented in early 1979 by the US Agency for International Development and the NASA Lewis Research Center. It is the only longitudinal field study of a developing country's renewable energy project, and continues to provide its services of water-pumping and grain-grinding to Tangaye villagers. The demonstration has two research foci: the reliability of a photovoltaic (PV) power system in harsh environmental conditions, and the appropriateness of PV technology from a social perspective as villagers mobilize to manage the system and integrate its services into their lives.

User evaluation of photovoltaic-powered vaccine refrigerator/freezer systems

NASA Technical Reports Server (NTRS)

Ratajczak, Anthony F.

1987-01-01

The NASA Lewis Research Center has concluded a project to develop and field test photovoltaic-powered refrigerator/freezers for vaccine storage in remote areas of developing countries. As a conclusion to this project, questionnaires were sent to the in-country administrators for each test site probing user acceptance of the systems and attitudes regarding procurement of additional systems. Responses indicate that the systems had a positive effect on the local communities, that they made a positive impression on the local health authorities, and that system cost and scarcity of funds are the major barriers to procurements of additional systems.

User evaluation of photovoltaic-powered vaccine refrigerator/freezer systems

NASA Astrophysics Data System (ADS)

Ratajczak, Anthony F.

1987-03-01

The NASA Lewis Research Center has concluded a project to develop and field test photovoltaic-powered refrigerator/freezers for vaccine storage in remote areas of developing countries. As a conclusion to this project, questionnaires were sent to the in-country administrators for each test site probing user acceptance of the systems and attitudes regarding procurement of additional systems. Responses indicate that the systems had a positive effect on the local communities, that they made a positive impression on the local health authorities, and that system cost and scarcity of funds are the major barriers to procurements of additional systems.

The goat domestication process inferred from large-scale mitochondrial DNA analysis of wild and domestic individuals

PubMed Central

Naderi, Saeid; Rezaei, Hamid-Reza; Pompanon, François; Blum, Michael G. B.; Negrini, Riccardo; Naghash, Hamid-Reza; Balkız, Özge; Mashkour, Marjan; Gaggiotti, Oscar E.; Ajmone-Marsan, Paolo; Kence, Aykut; Vigne, Jean-Denis; Taberlet, Pierre

2008-01-01

The emergence of farming during the Neolithic transition, including the domestication of livestock, was a critical point in the evolution of human kind. The goat (Capra hircus) was one of the first domesticated ungulates. In this study, we compared the genetic diversity of domestic goats to that of the modern representatives of their wild ancestor, the bezoar, by analyzing 473 samples collected over the whole distribution range of the latter species. This partly confirms and significantly clarifies the goat domestication scenario already proposed by archaeological evidence. All of the mitochondrial DNA haplogroups found in current domestic goats have also been found in the bezoar. The geographic distribution of these haplogroups in the wild ancestor allowed the localization of the main domestication centers. We found no haplotype that could have been domesticated in the eastern half of the Iranian Plateau, nor further to the east. A signature of population expansion in bezoars of the C haplogroup suggests an early domestication center on the Central Iranian Plateau (Yazd and Kerman Provinces) and in the Southern Zagros (Fars Province), possibly corresponding to the management of wild flocks. However, the contribution of this center to the current domestic goat population is rather low (1.4%). We also found a second domestication center covering a large area in Eastern Anatolia, and possibly in Northern and Central Zagros. This last domestication center is the likely origin of almost all domestic goats today. This finding is consistent with archaeological data identifying Eastern Anatolia as an important domestication center. PMID:19004765

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.

Effects of solar photovoltaic technology on the environment in China.

PubMed

Qi, Liqiang; Zhang, Yajuan

2017-10-01

Among the various types of renewable energy, solar photovoltaic has elicited the most attention because of its low pollution, abundant reserve, and endless supply. Solar photovoltaic technology generates both positive and negative effects on the environment. The environmental loss of 0.00666 yuan/kWh from solar photovoltaic technology is lower than that from coal-fired power generation (0.05216 yuan/kWh). The negative effects of solar photovoltaic system production include wastewater and waste gas pollutions, the representatives of which contain fluorine, chromium with wastewater and hydrogen fluoride, and silicon tetrachloride gas. Solar panels are also a source of light pollution. Improper disposal of solar cells that have reached the end of their service life harms the environment through the stench they produce and the damage they cause to the soil. So, the positive and negative effects of green energy photovoltaic power generation technology on the environment should be considered.

A photovoltaic self-powered gas sensor based on a single-walled carbon nanotube/Si heterojunction.

PubMed

Liu, L; Li, G H; Wang, Y; Wang, Y Y; Li, T; Zhang, T; Qin, S J

2017-12-07

We present a novel photovoltaic self-powered gas sensor based on a p-type single-walled carbon nanotube (SWNT) and n-type silicon (n-Si) heterojunction. The energy from visible light suffices to drive the device owing to a built-in electric field (BEF) induced by the differences between the Fermi levels of SWNTs and n-Si.

Improved ATIR concentrator photovoltaic module

NASA Astrophysics Data System (ADS)

Adriani, Paul M.; Mao, Erwang

2013-09-01

Novel aggregated total internal reflection (ATIR) concentrator photovoltaic module design comprises 2-D shaped primary and secondary optics that effectively combine optical efficiency, low profile, convenient range of acceptance angles, reliability, and manufacturability. This novel optical design builds upon previous investigations by improving the shapes of primary and secondary optics to enable improved long-term reliability and manufacturability. This low profile, low concentration (5x to 10x) design fits well with one-axis trackers that are often used for flat plate crystalline silicon photovoltaic modules in large scale ground mount installations. Standard mounting points, materials, and procedures apply without changes from flat plate modules.

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.

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.

Fluorinated tin oxide back contact for AZTSSe photovoltaic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gershon, Talia S.; Gunawan, Oki; Haight, Richard A.

A photovoltaic device includes a substrate, a back contact comprising a stable low-work function material, a photovoltaic absorber material layer comprising Ag.sub.2ZnSn(S,Se).sub.4 (AZTSSe) on a side of the back contact opposite the substrate, wherein the back contact forms an Ohmic contact with the photovoltaic absorber material layer, a buffer layer or Schottky contact layer on a side of the absorber layer opposite the back contact, and a top electrode on a side of the buffer layer opposite the absorber layer.

Cellules solaires photovoltaïques plastiques enjeux et perspectives

NASA Astrophysics Data System (ADS)

Sicot, L.; Dumarcher, V.; Raimond, P.; Rosilio, C.; Sentein, C.; Fiorini, C.

2002-04-01

Après avoir détaillé le fonctionnement d'une cellule photovoltaïque plastique et les paramètres photovoltaïques permettant de caractéiser son efficacité, un état de l'art des technologies de fabrication des cellules est présenté. Des moyens d'amélioration des performances des cellules photovoltaïques organiques sont ensuite illustrés par l'étude de dispositifs développés au Laboratoire Composants Organiques (LCO) du CEA Saclay.

Roadmap to Guide U.S. Photovoltaics Industry in 21st Century

Science.gov Websites

industry wants them to have it. Solar-cell manufacturers and suppliers see photovoltaics (PV) producing at Roadmap to Guide U.S. Photovoltaics Industry in 21st Century Solar energy will provide emergency Douglas Golden, Colo., Jan. 20, 2000 - Americans want clean solar electricity. The U.S. photovoltaics

Photovoltaic (PV) Systems Comparison at Fort Hood

DTIC Science & Technology

2010-06-01

Monocrystalline PV panels • Energy Photovoltaics, EPV-42 Solar Modules: Thin film PV panels • OutBack Flexware PV Advanced Photovoltaic Combiner...energy for an administrative building – Compare the performance between two different PV technologies: thin film and crystalline PV panels • Demo Team...Center for Energy and Environment PV Technology • Monocrystalline silicon1 • Thin film2 1 “About Solar,” DBK Corporation, http://www.dbksolar.com

Photovoltaic concentrator assembly with optically active cover

DOEpatents

Plesniak, Adam P

2014-01-21

A photovoltaic concentrator assembly that includes a housing that defines an internal volume and includes a rim, wherein the rim defines an opening into the internal volume, a photovoltaic cell positioned in the internal volume, and an optical element that includes an optically active body and a flange extending outward from the body, wherein the flange is sealingly engaged with the rim of the housing to enclose the internal volume.

Test and Evaluation Plan for the Manual Domestic Passive Profiling System (MDPPS)

DTIC Science & Technology

1994-02-01

Aviation Security (FAA/ACS) personnel and Northwest Airlines Security personnel. These elements were evaluated and refined at a Subject-Matter Expert (SME) workshop using Federal Bureau of Investigation (FBI), Immigration and Naturalization Service (INS), Customs, airline security personnel, and FAA personnel. A worksheet and scoring procedures for using the profiling elements were developed so that domestic passengers could be profiled by airline or other personnel. A field test of the feasibility of the Manual Domestic Passive Profiling (MDPP) worksheet was conducted at

Analysis of selected photovoltaic systems and storage options for residential applications in hot, humid climates

NASA Astrophysics Data System (ADS)

Lau, A. S.; Hill, J. M.; Ball, D. E.

1982-08-01

The relationship is studied between photovoltaic (PV) generated power and its on-site use as a function of total array size for an energy-efficient house in the hot, humid climates of Miami and Houston. Options in addition to be the full-roof system using a direct current (dc) to alternating current (ac) inverter are studied in an effort to identify applications which are less expensive and which rely less on utility sellback. The results show that common residential loads in this climate lead to high on-site utilization. For the various PV applications studied, array sizes are identified which can be fully potential is identified both in the house structure and the domestic water heater. Using projected 1986 costs, the economics of selected systems were studied for Miami. Only one of the system sizes was found to be marginally competitive with utility supplied power.

Application of clustering analysis in the prediction of photovoltaic power generation based on neural network

NASA Astrophysics Data System (ADS)

Cheng, K.; Guo, L. M.; Wang, Y. K.; Zafar, M. T.

2017-11-01

In order to select effective samples in the large number of data of PV power generation years and improve the accuracy of PV power generation forecasting model, this paper studies the application of clustering analysis in this field and establishes forecasting model based on neural network. Based on three different types of weather on sunny, cloudy and rainy days, this research screens samples of historical data by the clustering analysis method. After screening, it establishes BP neural network prediction models using screened data as training data. Then, compare the six types of photovoltaic power generation prediction models before and after the data screening. Results show that the prediction model combining with clustering analysis and BP neural networks is an effective method to improve the precision of photovoltaic power generation.

Optimization of Domestic-Size Renewable Energy System Designs Suitable for Cold Climate Regions

NASA Astrophysics Data System (ADS)

Akpan, Itoro Etim; Sasaki, Masafumi; Endoh, Noboru

Five different kinds of domestic-size renewable energy system configurations for very cold climate regions were investigated. From detailed numerical modeling and system simulations, it was found that the consumption of fuel oil for the auxiliary boiler in residential-type households can almost be eliminated with a renewable energy system that incorporates photovoltaic panel arrays for electricity generation and two storage tanks: a well-insulated electric water storage tank that services the hot water loads, and a compact boiler/geothermal heat pump tank for room heating during very cold seasons. A reduction of Greenhouse Gas Emissions (GHG) of about 28% was achieved for this system compared to an equivalent conventional system. The near elimination of the use of fuel oil in this system makes it very promising for very cold climate regions in terms of energy savings because the running cost is not so dependent on the unstable nature of global oil prices.

Photovoltaic power without batteries for continuous cathodic protection

NASA Technical Reports Server (NTRS)

Muehl, W. W., Sr.

1994-01-01

The COASTSYSTA designed, installed, and started up on 20 Jan. 1990, a state-of-the-art stand alone photovoltaic powered impressed current cathodic protection system (PVCPSYS) not requiring any auxiliary/battery backup power for steel and iron submerged structures. The PVCPSYS installed on 775' of steel sheet piling of a Navy bulkhead is continuing to provide complete, continuous corrosion protection. This has been well documented by COASTSYSTA and verified on-site by the U.S. Army Civil Engineering Research Laboratory, Champaign, Illinois and the Navy Energy Program Office-Photovoltaic Programs, China Lake, California. The Department of Defense (DoD) Photovoltaic Review Committee and Sandia National Laboratories consider this successful and cost effective system a major advance in the application of photovoltaic power. The PVCPSYS uses only renewable energy and is environmentally clean. A patent is pending on the new technology. Other possible PVCPSYS applications are mothballed ships, docks, dams, locks, bridges, marinas, offshore structures, and pipelines. The initial cost savings by installing a PVCPSYS vs. a conventional CP system was in excess of $46,000.00.

Photovoltaic solar energy conversion in the '80s

NASA Astrophysics Data System (ADS)

Chevalier, I.

1981-04-01

The potential for photovoltaic solar energy conversion in the generation of electricity to meet the needs of industrial and developing nations in the 1980s is discussed. The current technology of photovoltaic cells and modules, which are for the most part based on single crystal silicon and can deliver peak powers of 2 to 40 W at 6 to 12 V, is reviewed and prospects for cost reduction in the short- and medium-term by the development of new materials and production methods and increased cell efficiency and in the long term by the development of thin film cells, alternative compounds and mass production are indicated. Possible applications of photovoltaic-derived electricity are pointed out, including educational television receivers, rural telephones, refrigerators, water pumping and hospitals in developing nations and telecommunications, cathodic protection, signaling, telemetry and low-power pumping applications in industrial nations. Predictions of a photovoltaic peak Watt installed costing less than 10 francs by 1990 and a market above 100 MW in 1985 are pointed out.

Photovoltaic power without batteries for continuous cathodic protection

NASA Astrophysics Data System (ADS)

Muehl, W. W., Sr.

1994-02-01

The COASTSYSTA designed, installed, and started up on 20 Jan. 1990, a state-of-the-art stand alone photovoltaic powered impressed current cathodic protection system (PVCPSYS) not requiring any auxiliary/battery backup power for steel and iron submerged structures. The PVCPSYS installed on 775' of steel sheet piling of a Navy bulkhead is continuing to provide complete, continuous corrosion protection. This has been well documented by COASTSYSTA and verified on-site by the U.S. Army Civil Engineering Research Laboratory, Champaign, Illinois and the Navy Energy Program Office-Photovoltaic Programs, China Lake, California. The Department of Defense (DoD) Photovoltaic Review Committee and Sandia National Laboratories consider this successful and cost effective system a major advance in the application of photovoltaic power. The PVCPSYS uses only renewable energy and is environmentally clean. A patent is pending on the new technology. Other possible PVCPSYS applications are mothballed ships, docks, dams, locks, bridges, marinas, offshore structures, and pipelines. The initial cost savings by installing a PVCPSYS vs. a conventional CP system was in excess of $46,000.00.

Intermediate load-center photovoltaic application experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgess, E. L.

1980-01-01

A total of nine intermediate load-center photovoltaic systems were carried into the construction phase this year. These nine systems range in size from 20 to 225 kW/sub p/ electrical output and total almost 1 MW/sub p/. They are being installed in a diverse set of applications and locations and represent the bulk of the photovoltaic initial system evaluation experiments (ISEE) for the intermediate load-center sector. Each of these experiments are briefly described and the status of the construction phase is given for each project.

Multijunction photovoltaic device and fabrication method

DOEpatents

Arya, Rajeewa R.; Catalano, Anthony W.

1993-09-21

A multijunction photovoltaic device includes first and second amorphous silicon PIN photovoltaic cells in a stacked arrangement. An interface layer, composed of a doped silicon compound, is disposed between the two cells and has a lower bandgap than the respective n- and p-type adjacent layers of the first and second cells. The interface layer forms an ohmic contact with the one or the adjacent cell layers of the same conductivity type, and a tunnel junction with the other of the adjacent cell layers. The disclosed device is fabricated by a glow discharge process.

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.

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.

Monthly Solar Photovoltaic Module Shipments Report

EIA Publications

2017-01-01

This report contains newly collected monthly summary data beginning in January 2017, for the photovoltaic industry in the United States. The subset of respondents who now must report monthly represents approximately 90% of photovoltaic (PV) activity in the United States, based on prior year’s data. Data include manufacturing, imports, and exports of modules in the United States and its territories. Summary data include volumes in peak kilowatts and average prices. Where possible, imports and exports are listed by country, and shipments to the United States are listed by state.

SAM Photovoltaic Model Technical Reference 2016 Update

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilman, Paul; DiOrio, Nicholas A; Freeman, Janine M

This manual describes the photovoltaic performance model in the System Advisor Model (SAM) software, Version 2016.3.14 Revision 4 (SSC Version 160). It is an update to the 2015 edition of the manual, which describes the photovoltaic model in SAM 2015.1.30 (SSC 41). This new edition includes corrections of errors in the 2015 edition and descriptions of new features introduced in SAM 2016.3.14, including: 3D shade calculator Battery storage model DC power optimizer loss inputs Snow loss model Plane-of-array irradiance input from weather file option Support for sub-hourly simulations Self-shading works with all four subarrays, and uses same algorithm for fixedmore » arrays and one-axis tracking Linear self-shading algorithm for thin-film modules Loss percentages replace derate factors. The photovoltaic performance model is one of the modules in the SAM Simulation Core (SSC), which is part of both SAM and the SAM SDK. SAM is a user-friedly desktop application for analysis of renewable energy projects. The SAM SDK (Software Development Kit) is for developers writing their own renewable energy analysis software based on SSC. This manual is written for users of both SAM and the SAM SDK wanting to learn more about the details of SAM's photovoltaic model.« less

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.

Maximum power point tracker for photovoltaic power plants

NASA Astrophysics Data System (ADS)

Arcidiacono, V.; Corsi, S.; Lambri, L.

The paper describes two different closed-loop control criteria for the maximum power point tracking of the voltage-current characteristic of a photovoltaic generator. The two criteria are discussed and compared, inter alia, with regard to the setting-up problems that they pose. Although a detailed analysis is not embarked upon, the paper also provides some quantitative information on the energy advantages obtained by using electronic maximum power point tracking systems, as compared with the situation in which the point of operation of the photovoltaic generator is not controlled at all. Lastly, the paper presents two high-efficiency MPPT converters for experimental photovoltaic plants of the stand-alone and the grid-interconnected type.

Simulated hail impact testing of photovoltaic solar panels

NASA Technical Reports Server (NTRS)

Moore, D.; Wilson, A.; Ross, R.

1978-01-01

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

Photovoltaic Powering And Control System For Electrochromic Windows

DOEpatents

Schulz, Stephen C.; Michalski, Lech A.; Volltrauer, Hermann N.; Van Dine, John E.

2000-04-25

A sealed insulated glass unit is provided with an electrochromic device for modulating light passing through the unit. The electrochromic device is controlled from outside the unit by a remote control electrically unconnected to the device. Circuitry within the unit may be magnetically controlled from outside. The electrochromic device is powered by a photovoltaic cells. The photovoltaic cells may be positioned so that at least a part of the light incident on the cell passes through the electrochromic device, providing a form of feedback control. A variable resistance placed in parallel with the electrochromic element is used to control the response of the electrochromic element to changes in output of the photovoltaic cell.

Performance model for grid-connected photovoltaic inverters.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyson, William Earl; Galbraith, Gary M.; King, David L.

2007-09-01

This document provides an empirically based performance model for grid-connected photovoltaic inverters used for system performance (energy) modeling and for continuous monitoring of inverter performance during system operation. The versatility and accuracy of the model were validated for a variety of both residential and commercial size inverters. Default parameters for the model can be obtained from manufacturers specification sheets, and the accuracy of the model can be further refined using measurements from either well-instrumented field measurements in operational systems or using detailed measurements from a recognized testing laboratory. An initial database of inverter performance parameters was developed based on measurementsmore » conducted at Sandia National Laboratories and at laboratories supporting the solar programs of the California Energy Commission.« less

Experimental Studies on the Flammability and Fire Hazards of Photovoltaic Modules.

PubMed

Yang, Hong-Yun; Zhou, Xiao-Dong; Yang, Li-Zhong; Zhang, Tao-Lin

2015-07-09

Many of the photovoltaic (PV) systems on buildings are of sufficiently high voltages, with potential to cause or promote fires. However, research about photovoltaic fires is insufficient. This paper focuses on the flammability and fire hazards of photovoltaic modules. Bench-scale experiments based on polycrystalline silicon PV modules have been conducted using a cone calorimeter. Several parameters including ignition time ( t ig ), mass loss, heat release rate (HRR), carbon monoxide (CO) and carbon dioxide (CO₂) concentration, were investigated. The fire behaviours, fire hazards and toxicity of gases released by PV modules are assessed based on experimental results. The results show that PV modules under tests are inflammable with the critical heat flux of 26 kW/m². This work will lead to better understanding on photovoltaic fires and how to help authorities determine the appropriate fire safety provisions for controlling photovoltaic fires.

Effects of expiration of the Federal energy tax credit on the National Photovoltaics Program

NASA Technical Reports Server (NTRS)

Smith, J. L.

1984-01-01

Projected 1986 sales are significantly reduced as a direct result of system price increases following from expiration of the Federal energy tax credits. There would be greatly reduced emphasis on domestic electric utility applications. Indirect effects arising from unrealized economies of scale and reduced private investment in PV research and development (R&D) and in production facilities could have a very large cumulative adverse impact on the U.S. PV industry. The industry forecasts as much as fourfold reduction in 1990 sales if tax credits expire, compared with what sales would be with the credits. Because the National Photovoltaics Program is explicitly structured as a government partnership, large changes in the motivation or funding of either partner can affect Program success profoundly. Reduced industry participation implies that such industry tasks as industrialization and new product development would slow or halt. Those research areas receiving heavy R&D support from private PV manufacturers would be adversely affected.

Core questions in domestication research

PubMed Central

Zeder, Melinda A.

2015-01-01

The domestication of plants and animals is a key transition in human history, and its profound and continuing impacts are the focus of a broad range of transdisciplinary research spanning the physical, biological, and social sciences. Three central aspects of domestication that cut across and unify this diverse array of research perspectives are addressed here. Domestication is defined as a distinctive coevolutionary, mutualistic relationship between domesticator and domesticate and distinguished from related but ultimately different processes of resource management and agriculture. The relative utility of genetic, phenotypic, plastic, and contextual markers of evolving domesticatory relationships is discussed. Causal factors are considered, and two leading explanatory frameworks for initial domestication of plants and animals, one grounded in optimal foraging theory and the other in niche-construction theory, are compared. PMID:25713127

The enteritis complex in domestic rabbits: A field study.

PubMed

Percy, D H; Muckle, C A; Hampson, R J; Brash, M L

1993-02-01

A study of the causative agents of enteritis in domestic rabbits from 44 different accessions is described. In descending order of frequency, the organisms most commonly demonstrated were intestinal and hepatic coccidia (Eimeria species), Escherichia coli, Clostridium spp., Salmonella, Bacillus piliformis, and rotavirus. The species of Eimeria identified included those moderately pathogenic and coccidia of low pathogenicity. Using seven antisera against known enterpathogenic strains of E. coli, only one strain, O15, was identified in three cases. Clostridium perfringens or C. spiroforme was demonstrated in the intestinal contents in 11 cases, and lesions compatible with clostridial enteropathy were identified on gross and histopathology. In a serological survey, over 50% of 200 fryer rabbits submitted to Ontario abattoirs and of animals from commercial rabbitries had detectable antibody to rotavirus, indicating the widespread distribution of rotaviral infections in this species. In the cases of enteritis studied, two or more potentially pathogenic organisms were frequently identified, emphasizing that several different organisms may be acting in concert to produce clinical disease.

Performance Characterization of Dye-Sensitized Photovoltaics under Indoor Lighting.

PubMed

Chen, Chia-Yuan; Jian, Zih-Hong; Huang, Shih-Han; Lee, Kun-Mu; Kao, Ming-Hsuan; Shen, Chang-Hong; Shieh, Jia-Min; Wang, Chin-Li; Chang, Chiung-Wen; Lin, Bo-Zhi; Lin, Ching-Yao; Chang, Ting-Kuang; Chi, Yun; Chi, Cheng-Yu; Wang, Wei-Ting; Tai, Yian; Lu, Ming-De; Tung, Yung-Liang; Chou, Po-Ting; Wu, Wen-Ti; Chow, Tahsin J; Chen, Peter; Luo, Xiang-Hao; Lee, Yuh-Lang; Wu, Chih-Chung; Chen, Chih-Ming; Yeh, Chen-Yu; Fan, Miao-Syuan; Peng, Jia-De; Ho, Kuo-Chuan; Liu, Yu-Nan; Lee, Hsiao-Yi; Chen, Chien-Yu; Lin, Hao-Wu; Yen, Chia-Te; Huang, Yu-Ching; Tsao, Cheng-Si; Ting, Yu-Chien; Wei, Tzu-Chien; Wu, Chun-Guey

2017-04-20

Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE. Therefore, we use an illuminometer as a prime standard with a spectroradiometer to quantify the intensity of indoor lighting and adopt the reverse-biased current-voltage (I-V) characteristics as an indicator to qualify the I-V sampling time for dye-sensitized photovoltaics. The recommendations can brighten the prospects of emerging photovoltaics for indoor applications.

When domestic goes capital: Juror decision making in capital murder trials involving domestic homicide.

PubMed

Richards, Tara N; Smith, M Dwayne; Fogel, Sondra J; Bjerregaard, Beth

2015-08-01

Prior research suggests that homicide cases involving familial offenders and victims are subject to a "domestic discount" that reduces sentencing severity. However, the operation of a domestic discount in regard to death penalty sentencing has been rarely examined. The current research uses a near-population of jury decisions in capital murder trials conducted in North Carolina from 1991 to 2009 (n = 800), and a series of logistic regression analyses to determine whether there is (a) a direct effect between offender-victim relationship (e.g., domestic, friend/acquaintance, and stranger) and jury decision making, and/or (b) whether domestic offender-victim relationship (as well as other offender-victim relationships) moderates the effect of legal and extralegal case characteristics on jury assessment of the death penalty. Our findings revealed no empirical support for a "domestic discount" whereby juries are less likely to impose death sentences in cases involving domestic homicides. However, substantial differences in predictors of death sentencing were found across offender-victim dyads; most notably, domestic homicide cases demonstrated the most legalistic model of jury decisions to impose death sentences. (c) 2015 APA, all rights reserved).

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.

Photovoltaic research needs industry perspective

NASA Technical Reports Server (NTRS)

Ravi, K. V.

1982-01-01

An industries perspective of photovoltaic research needs is presented. Objectives and features of industry needs are discussed for the materials, devices, processes, and reliability research categories.

Electrochromic-photovoltaic film for light-sensitive control of optical transmittance

DOEpatents

Branz, H.M.; Crandall, R.S.; Tracy, C.E.

1994-12-27

A variable transmittance optical component includes an electrochromic material and a photovoltaic device-type thin film solar cell deposited in a tandem type, monolithic single coating over the component. A bleed resistor of a predetermined value is connected in series across the electrochromic material and photovoltaic device controlling the activation and deactivation of the electrochromic material. The electrical conductivity between the electrochromic material and the photovoltaic device is enhanced by interposing a transparent electrically conductive layer. 5 figures.

Electrochromic-photovoltaic film for light-sensitive control of optical transmittance

DOEpatents

Branz, Howard M.; Crandall, Richard S.; Tracy, C. Edwin

1994-01-01

A variable transmittance optical component includes an electrochromic material and a photovoltaic device-type thin film solar cell deposited in a tandem type, monolithic single coating over the component. A bleed resistor of a predetermined value is connected in series across the electrochromic material and photovoltaic device controlling the activation and deactivation of the electrochromic material. The electrical conductivity between the electrochromic material and the photovoltaic device is enhanced by interposing a transparent electrically conductive layer.

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.

Radiation Effects in Dual Heat Sinks for Cooling of Concentrated Photovoltaics

DTIC Science & Technology

2016-06-01

Schematic of a Concentrated Photovoltaic System . Source: [4]..................2 Figure 2. Temperature-Efficiency Curves of Select Solar Cells. Adapted from...in contrast to conventional systems . Conventional photovoltaics simply have incident solar radiation impinge on a semiconductor, CPV uses magnifying...reduce system cost. Figure 1 shows a concept schematic of a basic CPV system . Figure 1. Schematic of a Concentrated Photovoltaic System . Source

Photovoltaic systems sizing for Algeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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.more » 5 refs., 4 figs., 5 tabs.« less

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.

ACCURATE BUILDING INTEGRATED PHOTOVOLTAIC SYSTEM (BIPV) ARCHITECTURAL DESIGN TOOL

EPA Science Inventory

One of the leading areas of renewable energy applications for the twenty-first century is building integrated photovoltaics (BIPV). Integrating photovoltaics into building structures allows the costs of the PV system to be partially offset by the solar modules also serving a s...

Lightweight, self-ballasting photovoltaic roofing assembly

DOEpatents

Dinwoodie, T.L.

1998-05-05

A photovoltaic roofing assembly comprises a roofing membrane (102), a plurality of photovoltaic modules (104, 106, 108) disposed as a layer on top of the roofing membrane (102), and a plurality of pre-formed spacers, pedestals or supports (112, 114, 116, 118, 120, 122) which are respectively disposed below the plurality of photovoltaic modules (104, 106, 108) and integral therewith, or fixed thereto. Spacers (112, 114, 116, 118, 120, 122) are disposed on top of roofing membrane (102). Membrane (102) is supported on conventional roof framing, and attached thereto by conventional methods. In an alternative embodiment, the roofing assembly may have insulation block (322) below the spacers (314, 314', 315, 315'). The geometry of the preformed spacers (112, 114, 116, 118, 120, 122, 314, 314', 315, 315') is such that wind tunnel testing has shown its maximum effectiveness in reducing net forces of wind uplift on the overall assembly. Such construction results in a simple, lightweight, self-ballasting, readily assembled roofing assembly which resists the forces of wind uplift using no roofing penetrations.

Lightweight, self-ballasting photovoltaic roofing assembly

DOEpatents

Dinwoodie, Thomas L.

1998-01-01

A photovoltaic roofing assembly comprises a roofing membrane (102), a plurality of photovoltaic modules (104, 106, 108) disposed as a layer on top of the roofing membrane (102), and a plurality of pre-formed spacers, pedestals or supports (112, 114, 116, 118, 120, 122) which are respectively disposed below the plurality of photovoltaic modules (104, 106, 108) and integral therewith, or fixed thereto. Spacers (112, 114, 116, 118, 120, 122) are disposed on top of roofing membrane (102). Membrane (102) is supported on conventional roof framing, and attached thereto by conventional methods. In an alternative embodiment, the roofing assembly may have insulation block (322) below the spacers (314, 314', 315, 315'). The geometry of the preformed spacers (112, 114, 116, 118, 120, 122, 314, 314', 315, 315') is such that wind tunnel testing has shown its maximum effectiveness in reducing net forces of wind uplift on the overall assembly. Such construction results in a simple, lightweight, self-ballasting, readily assembled roofing assembly which resists the forces of wind uplift using no roofing penetrations.

Lightweight, self-ballasting photovoltaic roofing assembly

DOEpatents

Dinwoodie, Thomas L.

2006-02-28

A photovoltaic roofing assembly comprises a roofing membrane (102), a plurality of photovoltaic modules (104, 106, 108) disposed as a layer on top of the roofing membrane (102), and a plurality of pre-formed spacers, pedestals or supports (112, 114, 116, 118, 120, 122) which are respectively disposed below the plurality of photovoltaic modules (104, 106, 108) and integral therewith, or fixed thereto. Spacers (112, 114, 116, 118, 120, 122) are disposed on top of roofing membrane (102). Membrane (102) is supported on conventional roof framing, and attached thereto by conventional methods. In an alternative embodiment, the roofing assembly may have insulation block (322) below the spacers (314, 314', 315, 315'). The geometry of the pre-formed spacers (112, 114, 116, 118, 120, 122, 314, 314', 315, 315') is such that wind tunnel testing has shown its maximum effectiveness in reducing net forces of wind uplift on the overall assembly. Such construction results in a simple, lightweight, self-ballasting, readily assembled roofing assembly which resists the forces of wind uplift using no roofing penetrations.

Nitrogen and COD removal from domestic and synthetic wastewater in subsurface-flow constructed wetlands.

PubMed

Collison, R S; Grismer, M E

2013-09-01

Comparisons of the performance of constructed-wetland systems (CWs) for treating domestic wastewater in the laboratory and field may use pathogen-free synthetic wastewater to avoid regulatory health concerns. However, little to no data are available describing the relative treatment efficiencies of CWs to both actual and synthetic domestic wastewaters so as to enable such comparison. To fill this gap, treatment performances with respect to organics (chemical organic demand; COD) and nitrogen (ammonium and nitrate) removal from domestic (septic tank) and a similar-strength synthetic wastewater under planted and non-planted subsurface-flow CWs are determined. One pair of CWs was planted with cattails in May 2008, whereas the adjacent system was non-planted. Collected septic tank or synthesized wastewater was allowed to gravity feed each CWs, and effluent samples were collected and tested for COD and nitrogen species regularly during four different periods over six months. Overall, statistically significant greater removal of COD (-12%) and nitrogen (-5%) occurred from the synthetic as compared with the domestic wastewater from the planted and non-planted CWs. Effluent BOD5/COD ratios from the synthetic wastewater CWs averaged nearly twice that from the domestic wastewater CWs (0.17 vs 0.10), reflecting greater concentrations of readily degraded compounds. That removal fractions were consistent across the mid-range loading rates to the CWs suggests that the synthetic wastewater can be used in testing laboratory CWs with reasonable success in application of their results to the field.

Adaptive control paradigm for photovoltaic and solid oxide fuel cell in a grid-integrated hybrid renewable energy system.

PubMed

Mumtaz, Sidra; Khan, Laiq

2017-01-01

The hybrid power system (HPS) is an emerging power generation scheme due to the plentiful availability of renewable energy sources. Renewable energy sources are characterized as highly intermittent in nature due to meteorological conditions, while the domestic load also behaves in a quite uncertain manner. In this scenario, to maintain the balance between generation and load, the development of an intelligent and adaptive control algorithm has preoccupied power engineers and researchers. This paper proposes a Hermite wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control of photovoltaic (PV) systems to extract maximum power and a Hermite wavelet incorporated NeuroFuzzy indirect adaptive control of Solid Oxide Fuel Cells (SOFC) to obtain a swift response in a grid-connected hybrid power system. A comprehensive simulation testbed for a grid-connected hybrid power system (wind turbine, PV cells, SOFC, electrolyzer, battery storage system, supercapacitor (SC), micro-turbine (MT) and domestic load) is developed in Matlab/Simulink. The robustness and superiority of the proposed indirect adaptive control paradigm are evaluated through simulation results in a grid-connected hybrid power system testbed by comparison with a conventional PI (proportional and integral) control system. The simulation results verify the effectiveness of the proposed control paradigm.

Adaptive control paradigm for photovoltaic and solid oxide fuel cell in a grid-integrated hybrid renewable energy system

PubMed Central

Khan, Laiq

2017-01-01

The hybrid power system (HPS) is an emerging power generation scheme due to the plentiful availability of renewable energy sources. Renewable energy sources are characterized as highly intermittent in nature due to meteorological conditions, while the domestic load also behaves in a quite uncertain manner. In this scenario, to maintain the balance between generation and load, the development of an intelligent and adaptive control algorithm has preoccupied power engineers and researchers. This paper proposes a Hermite wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control of photovoltaic (PV) systems to extract maximum power and a Hermite wavelet incorporated NeuroFuzzy indirect adaptive control of Solid Oxide Fuel Cells (SOFC) to obtain a swift response in a grid-connected hybrid power system. A comprehensive simulation testbed for a grid-connected hybrid power system (wind turbine, PV cells, SOFC, electrolyzer, battery storage system, supercapacitor (SC), micro-turbine (MT) and domestic load) is developed in Matlab/Simulink. The robustness and superiority of the proposed indirect adaptive control paradigm are evaluated through simulation results in a grid-connected hybrid power system testbed by comparison with a conventional PI (proportional and integral) control system. The simulation results verify the effectiveness of the proposed control paradigm. PMID:28329015

Photovoltaic Universal Joints: Ball-and-Socket Interfaces in Molecular Photovoltaic Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tremblay, Noah J.; Gorodetsky, Alon A.; Cox, Marshall P.

2010-02-15

A new approach toward higher efficiency organic photovoltaic devices (OPVs) is described. Complementarity in shape between the donor (contorted hexabenzocoronene, see picture) and acceptor (buckminsterfullerene) molecules results in OPVs that perform surprisingly well. This exploitation of host-guest chemistry at the organic/organic interface demonstrates a new direction for OPV device design.

Entropy production in a photovoltaic cell

NASA Astrophysics Data System (ADS)

Ansari, Mohammad H.

2017-05-01

We evaluate entropy production in a photovoltaic cell that is modeled by four electronic levels resonantly coupled to thermally populated field modes at different temperatures. We use a formalism recently proposed, the so-called multiple parallel worlds, to consistently address the nonlinearity of entropy in terms of density matrix. Our result shows that entropy production is the difference between two flows: a semiclassical flow that linearly depends on occupational probabilities, and another flow that depends nonlinearly on quantum coherence and has no semiclassical analog. We show that entropy production in the cells depends on environmentally induced decoherence time and energy detuning. We characterize regimes where reversal flow of information takes place from a cold to hot bath. Interestingly, we identify a lower bound on entropy production, which sets limitations on the statistics of dissipated heat in the cells.

Singlet exciton fission photovoltaics.

PubMed

Lee, Jiye; Jadhav, Priya; Reusswig, Philip D; Yost, Shane R; Thompson, Nicholas J; Congreve, Daniel N; Hontz, Eric; Van Voorhis, Troy; Baldo, Marc A

2013-06-18

Singlet exciton fission, a process that generates two excitons from a single photon, is perhaps the most efficient of the various multiexciton-generation processes studied to date, offering the potential to increase the efficiency of solar devices. But its unique characteristic, splitting a photogenerated singlet exciton into two dark triplet states, means that the empty absorption region between the singlet and triplet excitons must be filled by adding another material that captures low-energy photons. This has required the development of specialized device architectures. In this Account, we review work to develop devices that harness the theoretical benefits of singlet exciton fission. First, we discuss singlet fission in the archetypal material, pentacene. Pentacene-based photovoltaic devices typically show high external and internal quantum efficiencies. They have enabled researchers to characterize fission, including yield and the impact of competing loss processes, within functional devices. We review in situ probes of singlet fission that modulate the photocurrent using a magnetic field. We also summarize studies of the dissociation of triplet excitons into charge at the pentacene-buckyball (C60) donor-acceptor interface. Multiple independent measurements confirm that pentacene triplet excitons can dissociate at the C60 interface despite their relatively low energy. Because triplet excitons produced by singlet fission each have no more than half the energy of the original photoexcitation, they limit the potential open circuit voltage within a solar cell. Thus, if singlet fission is to increase the overall efficiency of a solar cell and not just double the photocurrent at the cost of halving the voltage, it is necessary to also harvest photons in the absorption gap between the singlet and triplet energies of the singlet fission material. We review two device architectures that attempt this using long-wavelength materials: a three-layer structure that uses

Experimental Studies on the Flammability and Fire Hazards of Photovoltaic Modules

PubMed Central

Yang, Hong-Yun; Zhou, Xiao-Dong; Yang, Li-Zhong; Zhang, Tao-Lin

2015-01-01

Many of the photovoltaic (PV) systems on buildings are of sufficiently high voltages, with potential to cause or promote fires. However, research about photovoltaic fires is insufficient. This paper focuses on the flammability and fire hazards of photovoltaic modules. Bench-scale experiments based on polycrystalline silicon PV modules have been conducted using a cone calorimeter. Several parameters including ignition time (tig), mass loss, heat release rate (HRR), carbon monoxide (CO) and carbon dioxide (CO2) concentration, were investigated. The fire behaviours, fire hazards and toxicity of gases released by PV modules are assessed based on experimental results. The results show that PV modules under tests are inflammable with the critical heat flux of 26 kW/m2. This work will lead to better understanding on photovoltaic fires and how to help authorities determine the appropriate fire safety provisions for controlling photovoltaic fires. PMID:28793434

Developing a Practical Forecasting Screener for Domestic Violence Incidents

ERIC Educational Resources Information Center

Berk, Richard A.; He, Yan; Sorenson, Susan B.

2005-01-01

In this article, the authors report on the development of a short screening tool that deputies in the Los Angeles Sheriff's Department could use in the field to help forecast domestic violence incidents in particular households. The data come from more than 500 households to which sheriff's deputies were dispatched in fall 2003. Information on…

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.

Basics of the dimensioning and operations of photovoltaic systems

NASA Astrophysics Data System (ADS)

Karl, H.

1984-06-01

Experiments and results in solar energy research are discussed. The characteristics of solar cells and photovoltaic generators are examined, and long-term experimental results on solar generators and hybrid collectors are reported. Photovoltaic systems are discussed, including battery systems, water pump systems, and hydrogen production by electrolysis.

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.

Solar Power Wires Based on Organic Photovoltaic Materials

NASA Astrophysics Data System (ADS)

Lee, Michael R.; Eckert, Robert D.; Forberich, Karen; Dennler, Gilles; Brabec, Christoph J.; Gaudiana, Russell A.

2009-04-01

Organic photovoltaics in a flexible wire format has potential advantages that are described in this paper. A wire format requires long-distance transport of current that can be achieved only with conventional metals, thus eliminating the use of transparent oxide semiconductors. A phase-separated, photovoltaic layer, comprising a conducting polymer and a fullerene derivative, is coated onto a thin metal wire. A second wire, coated with a silver film, serving as the counter electrode, is wrapped around the first wire. Both wires are encased in a transparent polymer cladding. Incident light is focused by the cladding onto to the photovoltaic layer even when it is completely shadowed by the counter electrode. Efficiency values of the wires range from 2.79% to 3.27%.

Use of photovoltaics for waste heat recovery

DOEpatents

Polcyn, Adam D

2013-04-16

A device for recovering waste heat in the form of radiated light, e.g. red visible light and/or infrared light includes a housing having a viewing window, and a photovoltaic cell mounted in the housing in a relationship to the viewing window, wherein rays of radiated light pass through the viewing window and impinge on surface of the photovoltaic cell. The housing and/or the cell are cooled so that the device can be used with a furnace for an industrial process, e.g. mounting the device with a view of the interior of the heating chamber of a glass making furnace. In this manner, the rays of the radiated light generated during the melting of glass batch materials in the heating chamber pass through the viewing window and impinge on the surface of the photovoltaic cells to generate electric current which is passed onto an electric load.

Photovoltaic Subcontract Program. Annual report, FY 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

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,more » 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.« less

Lead Halide Perovskite Photovoltaic as a Model p-i-n Diode.

PubMed

Miyano, Kenjiro; Tripathi, Neeti; Yanagida, Masatoshi; Shirai, Yasuhiro

2016-02-16

The lead halide perovskite photovoltaic cells, especially the iodide compound CH3NH3PbI3 family, exhibited enormous progress in the energy conversion efficiency in the past few years. Although the first attempt to use the perovskite was as a sensitizer in a dye-sensitized solar cell, it has been recognized at the early stage of the development that the working of the perovskite photovoltaics is akin to that of the inorganic thin film solar cells. In fact, theoretically perovskite is always treated as an ordinary direct band gap semiconductor and hence the perovskite photovoltaics as a p-i-n diode. Despite this recognition, research effort along this line of thought is still in pieces and incomplete. Different measurements have been applied to different types of devices (different not only in the materials but also in the cell structures), making it difficult to have a coherent picture. To make the situation worse, the perovskite photovoltaics have been plagued by the irreproducible optoelectronic properties, most notably the sweep direction dependent current-voltage relationship, the hysteresis problem. Under such circumstances, it is naturally very difficult to analyze the data. Therefore, we set out to make hysteresis-free samples and apply time-tested models and numerical tools developed in the field of inorganic semiconductors. A series of electrical measurements have been performed on one type of CH3NH3PbI3 photovoltaic cells, in which a special attention was paid to ensure that their electronic reproducibility was better than the fitting error in the numerical analysis. The data can be quantitatively explained in terms of the established models of inorganic semiconductors: current/voltage relationship can be very well described by a two-diode model, while impedance spectroscopy revealed the presence of a thick intrinsic layer with the help of a numerical solver, SCAPS, developed for thin film solar cell analysis. These results point to that CH3NH3PbI3 is an

PHOTOVOLTAICS AND THE ENVIRONMENT 1998. REPORT ON THE WORKSHOP PHOTOVOLTAICS AND THE ENVIRONMENT 1999

DOE Office of Scientific and Technical Information (OSTI.GOV)

FTHENAKIS,V.; ZWEIBEL,K.; MOSKOWITZ,P.

1999-02-01

The objective of the workshop ``Photovoltaics and the Environment'' was to bring together PV manufacturers and industry analysts to define EH and S issues related to the large-scale commercialization of PV technologies.

Selection signature in domesticated animals.

PubMed

Pan, Zhang-yuan; He, Xiao-yun; Wang, Xiang-yu; Guo, Xiao-fei; Cao, Xiao-han; Hu, Wen-ping; Di, Ran; Liu, Qiu-yue; Chu, Ming-xing

2016-12-20

Domesticated animals play an important role in the life of humanity. All these domesticated animals undergo same process, first domesticated from wild animals, then after long time natural and artificial selection, formed various breeds that adapted to the local environment and human needs. In this process, domestication, natural and artificial selection will leave the selection signal in the genome. The research on these selection signals can find functional genes directly, is one of the most important strategies in screening functional genes. The current studies of selection signal have been performed in pigs, chickens, cattle, sheep, goats, dogs and other domestic animals, and found a great deal of functional genes. This paper provided an overview of the types and the detected methods of selection signal, and outlined researches of selection signal in domestic animals, and discussed the key issues in selection signal analysis and its prospects.

Optimized organic photovoltaics with surface plasmons

NASA Astrophysics Data System (ADS)

Omrane, B.; Landrock, C.; Aristizabal, J.; Patel, J. N.; Chuo, Y.; Kaminska, B.

2010-06-01

In this work, a new approach for optimizing organic photovoltaics using nanostructure arrays exhibiting surface plasmons is presented. Periodic nanohole arrays were fabricated on gold- and silver-coated flexible substrates, and were thereafter used as light transmitting anodes for solar cells. Transmission measurements on the plasmonic thin film made of gold and silver revealed enhanced transmission at specific wavelengths matching those of the photoactive polymer layer. Compared to the indium tin oxide-based photovoltaic cells, the plasmonic solar cells showed overall improvements in efficiency up to 4.8-fold for gold and 5.1-fold for the silver, respectively.

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.

A comprehensive analysis of the performance characteristics of the Mount Laguna solar photovoltaic installation

NASA Technical Reports Server (NTRS)

Shumka, A.; Sollock, S. G.

1981-01-01

This paper represents the first comprehensive survey of the Mount Laguna Photovoltaic Installation. The novel techniques used for performing the field tests have been effective in locating and characterizing defective modules. A comparative analysis on the two types of modules used in the array indicates that they have significantly different failure rates, different distributions in degradational space and very different failure modes. A life cycle model is presented to explain a multimodal distribution observed for one module type. A statistical model is constructed and it is shown to be in good agreement with the field data.

Low-Dimensional Nanomaterials as Active Layer Components in Thin-Film Photovoltaics

NASA Astrophysics Data System (ADS)

Shastry, Tejas Attreya

Thin-film photovoltaics offer the promise of cost-effective and scalable solar energy conversion, particularly for applications of semi-transparent solar cells where the poor absorption of commercially-available silicon is inadequate. Applications ranging from roof coatings that capture solar energy to semi-transparent windows that harvest the immense amount of incident sunlight on buildings could be realized with efficient and stable thin-film solar cells. However, the lifetime and efficiency of thin-film solar cells continue to trail their inorganic silicon counterparts. Low-dimensional nanomaterials, such as carbon nanotubes and two-dimensional metal dichalcogenides, have recently been explored as materials in thin-film solar cells due to their exceptional optoelectronic properties, solution-processability, and chemical inertness. Thus far, issues with the processing of these materials has held back their implementation in efficient photovoltaics. This dissertation reports processing advances that enable demonstrations of low-dimensional nanomaterials in thin-film solar cells. These low-dimensional photovoltaics show enhanced photovoltaic efficiency and environmental stability in comparison to previous devices, with a focus on semiconducting single-walled carbon nanotubes as an active layer component. The introduction summarizes recent advances in the processing of carbon nanotubes and their implementation through the thin-film photovoltaic architecture, as well as the use of two-dimensional metal dichalcogenides in photovoltaic applications and potential future directions for all-nanomaterial solar cells. The following chapter reports a study of the interaction between carbon nanotubes and surfactants that enables them to be sorted by electronic type via density gradient ultracentrifugation. These insights are utilized to construct of a broad distribution of carbon nanotubes that absorb throughout the solar spectrum. This polychiral distribution is then shown

Regenerable Photovoltaic Devices with a Hydrogel-Embedded Microvascular Network

PubMed Central

Koo, Hyung-Jun; Velev, Orlin D.

2013-01-01

Light-driven degradation of photoactive molecules could be one of the major obstacles to stable long term operation of organic dye-based solar light harvesting devices. One solution to this problem may be mimicking the regeneration functionality of a plant leaf. We report an organic dye photovoltaic system that has been endowed with such microfluidic regeneration functionality. A hydrogel medium with embedded channels allows rapid and uniform supply of photoactive reagents by a convection-diffusion mechanism. A washing-activation cycle enables reliable replacement of the organic component in a dye-sensitized photovoltaic system. Repetitive restoration of photovoltaic performance after intensive device degradation is demonstrated. PMID:23912814

Performance of a Prototype Stationary Catadioptric Concentrating Photovoltaic Module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lloyd, John V.; Kozodoy, Peter; Gladden, Christopher

A stationary catadioptric concentrating photovoltaic module with aperture area over 100 cm2, geometric concentration of 180x, and collection within 60° of polar incidence was designed, prototyped, and characterized. The module performance followed modeling closely with a peak power conversion efficiency of 26% for direct irradiance. Tracking of the sun is accomplished via translational micro-tracking completely internal to the module, avoiding the cost and complexity of mechanical two-axis trackers that point towards the sun. This study demonstrates the potential for concentrating photovoltaic modules with significantly higher efficiency than industry standard silicon photovoltaic modules that could be installed in stationary configurations onmore » rooftops.« less

Performance of a Prototype Stationary Catadioptric Concentrating Photovoltaic Module

DOE PAGES

Lloyd, John V.; Kozodoy, Peter; Gladden, Christopher; ...

2018-03-28

A stationary catadioptric concentrating photovoltaic module with aperture area over 100 cm2, geometric concentration of 180x, and collection within 60° of polar incidence was designed, prototyped, and characterized. The module performance followed modeling closely with a peak power conversion efficiency of 26% for direct irradiance. Tracking of the sun is accomplished via translational micro-tracking completely internal to the module, avoiding the cost and complexity of mechanical two-axis trackers that point towards the sun. This study demonstrates the potential for concentrating photovoltaic modules with significantly higher efficiency than industry standard silicon photovoltaic modules that could be installed in stationary configurations onmore » rooftops.« less

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.

75 FR 53277 - Notice of Workshop on Polymers for Photovoltaic Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-31

... photovoltaic systems; testing, performance, and reliability of polymers in photovoltaic systems; impact of... mentioned topics; presentation of a NIST- developed accelerated aging and service life prediction...

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.

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.

Synthesis of major economic studies of residential photovoltaics

NASA Technical Reports Server (NTRS)

1984-01-01

Six studies that analyze the cost effectiveness of grid connected residential photovoltaic systems are reviewed. These six studies were selected based on two criteria. First, the reports share common emphases on developing photovoltaic systems with certain engineering design goals in mind, and on performing economic analyses to assess the long term economic potential of the system design. The economic analyses presented are performed from the consumer's perspective.

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.

Non-fullerene electron acceptors for organic photovoltaic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenekhe, Samson A.; Li, Haiyan; Earmme, Taeshik

Non-fullerene electron acceptors for highly efficient organic photovoltaic devices are described. The non-fullerene electron acceptors have an extended, rigid, .pi.-conjugated electron-deficient framework that can facilitate exciton and charge derealization. The non-fullerene electron acceptors can physically mix with a donor polymer and facilitate improved electron transport. The non-fullerene electron acceptors can be incorporated into organic electronic devices, such as photovoltaic cells.

Semiconductor electrolyte photovoltaic energy converter

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Anderson, L. B.

1975-01-01

Feasibility and practicality of a solar cell consisting of a semiconductor surface in contact with an electrolyte are evaluated. Basic components and processes are detailed for photovoltaic energy conversion at the surface of an n-type semiconductor in contact with an electrolyte which is oxidizing to conduction band electrons. Characteristics of single crystal CdS, GaAs, CdSe, CdTe and thin film CdS in contact with aqueous and methanol based electrolytes are studied and open circuit voltages are measured from Mott-Schottky plots and open circuit photo voltages. Quantum efficiencies for short circuit photo currents of a CdS crystal and a 20 micrometer film are shown together with electrical and photovoltaic properties. Highest photon irradiances are observed with the GaAs cell.

The Brain of the Domestic Bos taurus: Weight, Encephalization and Cerebellar Quotients, and Comparison with Other Domestic and Wild Cetartiodactyla.

PubMed

Ballarin, Cristina; Povinelli, Michele; Granato, Alberto; Panin, Mattia; Corain, Livio; Peruffo, Antonella; Cozzi, Bruno

2016-01-01

The domestic bovine Bos taurus is raised worldwide for meat and milk production, or even for field work. However the functional anatomy of its central nervous system has received limited attention and most of the reported data in textbooks and reviews are derived from single specimens or relatively old literature. Here we report information on the brain of Bos taurus obtained by sampling 158 individuals, 150 of which at local abattoirs and 8 in the dissecting room, these latter subsequently formalin-fixed. Using body weight and fresh brain weight we calculated the Encephalization Quotient (EQ), and Cerebellar Quotient (CQ). Formalin-fixed brains sampled in the necropsy room were used to calculate the absolute and relative weight of the major components of the brain. The data that we obtained indicate that the domestic bovine Bos taurus possesses a large, convoluted brain, with a slightly lower weight than expected for an animal of its mass. Comparisons with other terrestrial and marine members of the order Cetartiodactyla suggested close similarity with other species with the same feeding adaptations, and with representative baleen whales. On the other hand differences with fish-hunting toothed whales suggest separate evolutionary pathways in brain evolution. Comparison with the other large domestic herbivore Equus caballus (belonging to the order Perissodactyla) indicates that Bos taurus underwent heavier selection of bodily traits, which is also possibly reflected in a comparatively lower EQ than in the horse. The data analyzed suggest that the brain of domestic bovine is potentially interesting for comparative neuroscience studies and may represents an alternative model to investigate neurodegeneration processes.