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

Simpson, L.; Britt, J.; Birkmire, R.

ITN Energy Systems, Inc., and Global Solar Energy, Inc., assisted by NREL's PV Manufacturing R&D program, have continued to advance CIGS production technology by developing trajectory-oriented predictive/control models, fault-tolerance control, control platform development, in-situ sensors, and process improvements. Modeling activities included developing physics-based and empirical models for CIGS and sputter-deposition processing, implementing model-based control, and applying predictive models to the construction of new evaporation sources and for control. Model-based control is enabled by implementing reduced or empirical models into a control platform. Reliability improvement activities include implementing preventive maintenance schedules; detecting failed sensors/equipment and reconfiguring to tinue processing; and systematicmore » development of fault prevention and reconfiguration strategies for the full range of CIGS PV production deposition processes. In-situ sensor development activities have resulted in improved control and indicated the potential for enhanced process status monitoring and control of the deposition processes. Substantial process improvements have been made, including significant improvement in CIGS uniformity, thickness control, efficiency, yield, and throughput. In large measure, these gains have been driven by process optimization, which in turn have been enabled by control and reliability improvements due to this PV Manufacturing R&D program.« less

Materials and Devices | Photovoltaic Research | NREL

Science.gov Websites

Polycrystalline Thin-Film PV Cadmium telluride (CdTe) solar cells Copper indium gallium diselenide (CIGS) solar cells Perovskite and Organic PV Perovskite solar cells Perovskite Patent Portfolio Organic PV (OPV ) solar cells Advanced Materials, Devices, and Concepts We explore new PV materials using high-throughput

Research | Photovoltaic Research | NREL

Science.gov Websites

-V cells Hybrid tandems Polycrystalline Thin-Film PV CdTe solar cells CIGS solar cells Perovskites and Organic PV Perovskite solar cells Organic PV solar cells Advanced Materials, Devices, and Science Interfacial and Surface Science Reliability and Engineering Real-Time PV and Solar Resource

Controlling Metastable Native Point-Defect Populations in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 Materials and Solar Cells through Voltage-Bias Annealing

DOE PAGES

Teeter, Glenn; Harvey, Steve P.; Johnston, Steve

2017-01-30

Our contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu 2ZnSnSe 4 (CZTSe), Cu(In,Ga)Se 2 (CIGS), and CdS material properties and solar cell performance. In order to quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 degrees C to 215 degrees C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200more » degrees C for CIGS and 110 degrees C-215 degrees C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Our results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.« less

Controlling metastable native point-defect populations in Cu(In,Ga)Se2 and Cu2ZnSnSe4 materials and solar cells through voltage-bias annealing

NASA Astrophysics Data System (ADS)

Teeter, G.; Harvey, S. P.; Johnston, S.

2017-01-01

This contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu2ZnSnSe4 (CZTSe), Cu(In,Ga)Se2 (CIGS), and CdS material properties and solar cell performance. To quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 °C to 215 °C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200 °C for CIGS and 110 °C-215 °C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.

Controlling Metastable Native Point-Defect Populations in Cu(In,Ga)Se 2 and Cu 2ZnSnSe 4 Materials and Solar Cells through Voltage-Bias Annealing

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

Teeter, Glenn; Harvey, Steve P.; Johnston, Steve

Our contribution describes the influence of low-temperature annealing with and without applied voltage bias on thin-film Cu 2ZnSnSe 4 (CZTSe), Cu(In,Ga)Se 2 (CIGS), and CdS material properties and solar cell performance. In order to quantify the effects of cation disorder on CZTSe device performance, completed devices were annealed under open-circuit conditions at various temperatures from 110 degrees C to 215 degrees C and subsequently quenched. Measurements on these devices document systematic, reversible changes in solar-cell performance consistent with a reduction in CZTSe band tails at lower annealing temperatures. CIGS and CZTSe solar cells were also annealed at various temperatures (200more » degrees C for CIGS and 110 degrees C-215 degrees C for CZTSe) and subsequently quenched with continuously applied voltage bias to explore the effects of non-equilibrium annealing conditions. For both absorbers, large reversible changes in device characteristics correlated with the magnitude and sign of the applied voltage bias were observed. For CZTSe devices, the voltage-bias annealing (VBA) produced reversible changes in open-circuit voltage (VOC) from 289 meV to 446 meV. For CIGS solar cells, even larger changes were observed in device performance: photovoltaic (PV) conversion efficiency of the CIGS device varied from below 3% to above 15%, with corresponding changes in CIGS hole density of about three orders of magnitude. Findings from these VBA experiments are interpreted in terms of changes to the metastable point-defect populations that control key properties in the absorber layers, and in the CdS buffer layer. Computational device modeling was performed to assess the impacts of cation disorder on the CZTSe VOC deficit, and to elucidate the effects of VBA treatments on metastable point defect populations in CZTSe, CIGS, and CdS. Our results indicate that band tails impose important limitations on CZTSe device performance. Device modeling results also indicate that non-equilibrium processing conditions including the effects of voltage bias can dramatically alter point-defect-mediated opto-electronic properties of semiconductors. Implications for optimization of PV materials and connections to long-term stability of PV devices are discussed.« less

CIGS2 Thin-Film Solar Cells on Flexible Foils for Space Power

NASA Technical Reports Server (NTRS)

Dhere, Neelkanth G.; Ghongadi, Shantinath R.; Pandit, Mandar B.; Jahagirdar, Anant H.; Scheiman, David

2002-01-01

CuIn(1-x)Ga(x)S2 (CIGS2) thin-film solar cells are of interest for space power applications because of the near optimum bandgap for AM0 solar radiation in space. CIGS2 thin film solar cells on flexible stainless steel (SS) may be able to increase the specific power by an order of magnitude from the current level of 65 Wkg(sup -1). CIGS solar cells are superior to the conventional silicon and gallium arsenide solar cells in the space radiation environment. This paper presents research efforts for the development of CIGS2 thin-film solar cells on 127 micrometers and 20 micrometers thick, bright-annealed flexible SS foil for space power. A large-area, dual-chamber, inline thin film deposition system has been fabricated. The system is expected to provide thickness uniformity of plus or minus 2% over the central 5" width and plus or minus 3% over the central 6" width. During the next phase, facilities for processing larger cells will be acquired for selenization and sulfurization of metallic precursors and for heterojunction CdS layer deposition both on large area. Small area CIGS2 thin film solar cells are being prepared routinely. Cu-rich Cu-Ga/In layers were sputter-deposited on unheated Mo-coated SS foils from CuGa (22%) and In targets. Well-adherent, large-grain Cu-rich CIGS2 films were obtained by sulfurization in a Ar: H2S 1:0.04 mixture and argon flow rate of 650 sccm, at the maximum temperature of 475 C for 60 minutes with intermediate 30 minutes annealing step at 120 C. Samples were annealed at 500 C for 10 minutes without H2S gas flow. The intermediate 30 minutes annealing step at 120 C was changed to 135 C. p-type CIGS2 thin films were obtained by etching the Cu-rich layer segregated at the surface using dilute KCN solution. Solar cells were completed by deposition of CdS heterojunction partner layer by chemical bath deposition, transparent-conducting ZnO/ZnO: Al window bilayer by RF sputtering, and vacuum deposition of Ni/Al contact fingers through metal mask. PV parameters of a CIGS2 solar cell on 127 micrometers thick SS flexible foil measured under AM 0 conditions at NASA GRC were: V(sub oc) = 802.9 mV, J(sub sc) = 25.07 mA per square centimeters, FF = 60.06%, and efficiency 0 = 8.84%. For this cell, AM 1.5 PV parameters measured at NREL were: V(sub oc) = 788 mV, J(sub sc) = 19.78 mA per square centimeter, FF = 59.44%, efficiency 0 = 9.26%. Quantum efficiency curve showed a sharp QE cutoff equivalent to CIGS2 bandgap of approximately 1.50 eV, fairly close to the optimum value for efficient AM0 PV conversion in the space.

Multiple-Color-Generating Cu(In,Ga)(S,Se)2 Thin-Film Solar Cells via Dichroic Film Incorporation for Power-Generating Window Applications.

PubMed

Yoo, Gang Yeol; Jeong, Jae-Seung; Lee, Soyoung; Lee, Youngki; Yoon, Hee Chang; Chu, Van Ben; Park, Gi Soon; Hwang, Yun Jeong; Kim, Woong; Min, Byoung Koun; Do, Young Rag

2017-05-03

There are four prerequisites when applying all types of thin-film solar cells to power-generating window photovoltaics (PVs): high power-generation efficiency, longevity and high durability, semitransparency or partial-light transmittance, and colorful and aesthetic value. Solid-type thin-film Cu(In,Ga)S 2 (CIGS) or Cu(In,Ga)(S,Se) 2 (CIGSSe) PVs nearly meet the first two criteria, making them promising candidates for power-generating window applications if they can transmit light to some degree and generate color with good aesthetic value. In this study, the mechanical scribing process removes 10% of the window CIGSSe thin-film solar cell with vacant line patterns to provide a partial-light-transmitting CIGSSe PV module to meet the third requirement. The last concept of creating distinct colors could be met by the addition of reflectance colors of one-dimensional (1D) photonic crystal (PC) dichroic film on the black part of a partial-light-transmitting CIGSSe PV module. Beautiful violets and blues were created on the cover glass of a black CIGSSe PV module via the addition of 1D PC blue-mirror-yellow-pass dichroic film to improve the aesthetic value of the outside appearance. As a general result from the low external quantum efficiency (EQE) and absorption of CIGSSe PVs below a wavelength of 400 nm, the harvesting efficiency and short-circuit photocurrent of CIGSSe PVs were reduced by only ∼10% without reducing the open-circuit voltage (V OC ) because of the reduced overlap between the absorption spectrum of CIGSSe PV and the reflectance spectrum of the 1D PC blue-mirror-yellow-pass dichroic film. The combined technology of partial-vacancy-scribed CIGSSe PV modules and blue 1D PC dichroic film can provide a simple strategy to be applied to violet/blue power-generating window applications, as such a strategy can improve the transparency and aesthetic value without significantly sacrificing the harvesting efficiency of the CIGSSe PV modules.

All-Nonvacuum-Processed CIGS Solar Cells Using Scalable Ag NWs/AZO-Based Transparent Electrodes.

PubMed

Wang, Mingqing; Choy, Kwang-Leong

2016-07-06

With record cell efficiency of 21.7%, CIGS solar cells have demonstrated to be a very promising photovoltaic (PV) technology. However, their market penetration has been limited due to the inherent high cost of the cells. In this work, to lower the cost of CIGS solar cells, all nonvacuum-processed CIGS solar cells were designed and developed. CIGS absorber was prepared by the annealing of electrodeposited metallic layers in a chalcogen atmosphere. Nonvacuum-deposited Ag nanowires (NWs)/AZO transparent electrodes (TEs) with good transmittance (92.0% at 550 nm) and high conductivity (sheet resistance of 20 Ω/□) were used to replace the vacuum-sputtered window layer. Additional thermal treatment after device preparation was conducted at 220 °C for a few of minutes to improve both the value and the uniformity of the efficiency of CIGS pixel cell on 5 × 5 cm substrate. The best performance of the all-nonvacuum-fabricated CIGS solar cells showed an efficiency of 14.05% with Jsc of 34.82 mA/cm(2), Voc of 0.58 V, and FF of 69.60%, respectively, which is comparable with the efficiency of 14.45% of a reference cell using a sputtered window layer.

Optical Metrology for CIGS Solar Cell Manufacturing and its Cost Implications

NASA Astrophysics Data System (ADS)

Sunkoju, Sravan Kumar

Solar energy is a promising source of renewable energy which can meet the demand for clean energy in near future with advances in research in the field of photovoltaics and cost reduction by commercialization. Availability of a non-contact, in-line, real time robust process control strategies can greatly aid in reducing the gap between cell and module efficiencies, thereby leading to cost-effective large-scale manufacturing of high efficiency CIGS solar cells. In order to achieve proper process monitoring and control for the deposition of the functional layers of CuIn1-xGaxSe 2 (CIGS) based thin film solar cell, optical techniques such as spectroscopic reflectometry and polarimetry are advantageous because they can be set up in an unobtrusive manner in the manufacturing line, and collect data in-line and in-situ. The use of these techniques requires accurate optical models that correctly represent the properties of the layers being deposited. In this study, Spectroscopic ellipsometry (SE) has been applied for the characterization of each individual stage of CIGS layers deposited using the 3-stage co-evaporation process along with the other functional layers. Dielectric functions have been determined for the energy range from 0.7 eV to 5.1 eV. Critical-point line-shape analysis was used in this study to determine the critical point energies of the CIGS based layers. To control the compositional and thickness uniformity of all the functional layers during the fabrication of CIGS solar cells over large areas, multilayer photovoltaics (PV) stack optical models were developed with the help of extracted dielectric functions. In this study, mapping capability of RC2 spectroscopic ellipsometer was used to map all the functional layer thicknesses of a CIGS solar cell in order to probe the spatial non-uniformities that can affect the performance of a cell. The optical functions for each of the stages of CIGS 3-stage deposition process along with buffer layer and transparent conducting oxide (TCO) bi-layer, thus derived were used in a fiber optic-based spectroscopic reflectometry optical monitoring system installed in the pilot line at the PVMC's Halfmoon facility. Results obtained from this study show that the use of regular fiber optics, instead of polarization-maintaining fiber optics, is sufficient for the purpose of process monitoring. Also, the technique does not need to be used "in-situ", but the measurements can be taken in-line, and are applicable to a variety of deposition techniques used for different functional layers deposited on rigid or flexible substrates. In addition, effect of Cu concentration on the CIGS optical properties has been studied. Mixed CIGS/Cu2-xSe phase was observed at the surface at the end of the second stage of 3-stage deposition process, under Cu-rich conditions. A significant change in optical behavior of CIGS due to Cu2-xSe at the surface was observed under Cu-rich conditions, which can be used as end-point detection method to move from 2nd stage to 3rd stage in the deposition process. Developed optical functions were applied to in-line reflectance measurements not only to identify the Cu2-xSe phase at the surface but also to measure the thickness of the mixed CIGS/Cu2-xSe layer. This spectroscopic reflectometry based in-line process control technique can be used for end-point detection as well as to control thickness during the preparation of large area CIGS films. These results can assist in the development of optical process-control tools for the manufacturing of high quality CIGS based photovoltaic cells, increasing the uptime and yield of the production line. Finally, to understand the cost implications, low cost potential of two different deposition technologies has been studied on both rigid and flexible substrates with the help of cost analysis. Cost advantages of employing a contactless optics based process control technique have been investigated in order to achieve a low cost of < 0.5 $/W for CIGS module production. Based on cost analysis, one of the best strategies for achieving the low cost targets would be increasing manufacturing throughput, using roll-to-roll thin-film module manufacturing, with co-evaporation and chemical bath deposition processes for absorber and buffer layer respectively, while applying a low-cost process control technique such as spectroscopic reflectometry to improve module efficiencies and maintain high yield.

Spectroscopic ellipsometry for analysis of polycrystalline thin-film photovoltaic devices and prediction of external quantum efficiency

NASA Astrophysics Data System (ADS)

Ibdah, Abdel-Rahman; Koirala, Prakash; Aryal, Puruswottam; Pradhan, Puja; Marsillac, Sylvain; Rockett, Angus A.; Podraza, Nikolas J.; Collins, Robert W.

2017-11-01

Complete polycrystalline thin-film photovoltaic (PV) devices employing CuIn1-xGaxSe2/CdS and CdS/CdTe heterojunctions have been studied by ex situ spectroscopic ellipsometry (SE). In this study, layer thicknesses have been extracted along with photon energy independent parameters such as compositions that describe the dielectric function spectra ε(E) of the individual layers. For accurate ex situ SE analysis of these PV devices, a database of ε(E) spectra is required for all thin film component materials used in each of the two absorber technologies. When possible, database measurements are performed by applying SE in situ immediately after deposition of the thin film materials and after cooling to room temperature in order to avoid oxidation and surface contamination. Determination of ε(E) from the resulting in situ SE data requires structural information that can be obtained from analysis of SE data acquired in real time during the deposition process. From the results of ex situ analysis of the complete CuIn1-xGaxSe2 (CIGS) and CdTe PV devices, the deduced layer thicknesses in combination with the parameters describing ε(E) can be employed in further studies that simulate the external quantum efficiency (EQE) spectra of the devices. These simulations have been performed here by assuming that all electron-hole pairs generated within the active layers, i.e. layers incorporating a dominant absorber component (either CIGS or CdTe), are separated and collected. The active layers may include not only the bulk absorber but also window and back contact interface layers, and individual current contributions from these layers have been determined in the simulations. In addition, the ex situ SE analysis results enable calculation of the absorbance spectra for the inactive layers and the overall reflectance spectra, which lead to quantification of all optical losses in terms of a current density deficit. Mapping SE can be performed given the high speed of multichannel ellipsometers employing array detection, and the resulting EQE simulation capability has wide applications in predicting large area PV module output. The ultimate goal is an on-line capability that enables prediction of PV sub-cell current output as early as possible in the production process.

Understanding the Effect of Na in Improving the Performance of CuInSe 2 Based Photovoltaics

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

Dobson, Kevin D.

Cu(In,Ga)Se 2 (CIGS) thin film photovoltaic technology is in the early stages of commercialization with an annual manufacturing capacity over 1 GW and has demonstrated the highest module efficiency of any of the thin film technologies. However there still is a lack of fundamental understanding of the relationship between the material properties and solar cell device operation. It is well known that the incorporation of a small amount of Na into the CIGS film during processing is essential for high efficiency devices. However, there are conflicting explanations for how Na behaves at the atomic scale. This report investigates how Namore » is incorporated into the CIGS device structure and evaluates the diffusion of Na into CIGS grain boundaries (GBs) and bulk crystallites. Participants: This project was carried out at the Institute of Energy Conversion at the University of Delaware, collaborating with the Rockett group at the University of Illinois Urbana-Champagne. Significant Findings: The significant outcomes of this project for each task include; Task 1.0: Effect of Na in Devices Fabricated on PVD Deposited CIGS; Na diffusion occurs through the Mo back contact via GBs driven by the presence of oxygen; Na reversibly compensates donor defects in CIGS GBs,Task 2.0: Na Incorporation in Single Crystal CIGS; and bulk Na diffusion proceeds rapidly such that grains are Na-saturated immediately following CIGS thin film manufacture. Industry Guidance: The presented results offer interesting concepts for modification of manufacturing processes of CIGS-based PV modules. Possible approaches to improve control of Na uptake and uniformly increase levels in CIGS films are highlighted for processes that employ either soda-lime glass or NaF as the Na source. Concepts include the potential of O 2 or oxidative based treatments of Mo back contacts to improve Na diffusion through the metal film and increase Na uptake into the growing CIGS. This project has also offered fundamental understanding of the behavior of Na in CIGS grains and GBs, particularly the confirmation that CIGS grains will be saturated with Na immediately following manufacture Summary of Results: Most commercially available CIGS modules are fabricated on soda-lime glass coated with Mo as the back electric contact, and Na in the glass diffuses through the Mo layer into the CIGS during film growth. In Task 1 the transport of Na through Mo was evaluated using x-ray photoelectron surface spectroscopy along with diffusion modeling to obtain diffusion coefficients at several temperatures. It was determined that Na diffusion in Mo only occurs along GBs and that oxygen provides an additional driving force to enhance Na transport. Device data revealed that older Mo substrates with a greater amount of surface oxide resulted in slightly higher efficiencies due to enhanced Na incorporation caused by the oxide. This finding shows that Mo substrates could potentially undergo an oxidation treatment prior to CIGS deposition to further improve and control the incorporation of Na. To determine if in-grain Na affects device performance, in Task 1 Na was selectively removed from GBs using heat/rinse cycles. Due to the low temperature of this treatment, Na at GBS remained mobile while diffusion within the bulk was too slow for Na removal from the grain interiors. Changes in electrical properties were evaluated using conductivity and Seebeck coefficient measurements, with both decreasing as Na was removed to reach values similar to Na-free controls samples. This can be explained by the compensation of donor defects by Na, causing an increase in the free carrier concentration. Devices showed a decrease in open-circuit voltage after Na removal confirming that the beneficial effects of GB Na. The findings of this project will provide guidance for rational optimization of Na incorporation procedures in the manufacturing of CIGS solar cells. While it is known that Na segregates at CIGS GBs, the nature and role of Na diffusion into grain interiors was less clear. In Task 2, single crystal CuInSe 2 was used as a model system to represent the grain interiors of CIGS. Crystals processed by two different methods of different compositions and dislocation densities, were evaluated. Diffusion coefficients were obtained at two temperatures after Na diffusion, giving near identical values, ~2x10 11 cm 2/s and ~6x10 11 cm2/s at 420°C and 480°C, respectively, for each crystal. Characterization confirmed that dislocation densities were too low to significantly impact the effective diffusion coefficient. The Cu-poor crystal had a higher solubility suggesting that Na diffusion is mediated by Cu-vacancies, but was not accompanied by an expected increase in diffusion coefficient. The activation energy for diffusion was similar to values expected for interstitial diffusion, but the large size of Na + ions should result in a solubility that is much lower than what was experimentally measured. A hybrid interstitial-substitutional mechanism is proposed that combines the fast diffusion of interstitial atoms with the high solubility common for substitutional impurities. Lattice diffusion of Na proceeds fast enough that CIGS grain interiors will have Na concentrations near the solubility limit of 1018 cm -3 when manufactured under standard conditions. Na and K treated epitaxial CIS films showed a significant increase in cathodoluminescence emission intensity, indicating a reduction of non-radiative recombination pathways, which is consistent with improvements in CIGS device performance, though the mechanism is not clear. Pathways forward: Despite the success of this project, there are a number of questions remaining related to further the understanding of the chemistry of Na in CIGS films and devices. These include further elucidation of the mechanisms of Na passivation in CIGS GBs, with identification of which defects are involved and confirmation of the possible effects of in-grain Na on device performance. To complete analysis of the cell structure, conformation of the presence and possible chemistries of Na at the CIGS/CdS junction and/or in the front transparent contacts, and its effects on device performance, is needed.« less

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

Cu(In,Ga)(Se,S)2 solar cell research in Solar Frontier: Progress and current status

NASA Astrophysics Data System (ADS)

Kato, Takuya

2017-04-01

As the largest manufacturer of Cu(In,Ga)(Se,S)2 (CIGS) thin-film photovoltaic modules with more than 1 GW/year production volume, Solar Frontier K.K. has continuously improved module performance and small-area cell efficiencies in the laboratory. Because of our low-cost and environmentally-friendly process, Solar Frontier’s CIGS is a promising technology for the mass production of photovoltaic modules to fill ever-increasing demand. Recently we have achieved certified efficiencies of 22.3 and 22.0% on CdS-buffered and Cd-free buffered small-area cells, respectively, as well as 18.6% on a Cd-free mini-module. In this paper, a review of our CIGS technology and recent progress on the development of the module and the small-area cell is presented.

Identification and Analysis of Partial Shading Breakdown Sites in CuIn xGa (1-x)Se 2 Modules

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

Palmiotti, Elizabeth; Johnston, Steven; Gerber, Andreas

In this paper, CuIn xGa (1-x) (CIGS) mini-modules are stressed under reverse bias, resembling partial shading conditions, to predict and characterize where failures occur. Partial shading can cause permanent damage in the form of 'wormlike' defects on thin-film modules due to thermal runaway. This results in module-scale power losses. We have used dark lock-in thermography (DLIT) to spatially observe localized heating when reverse-bias breakdown occurs on various CIGS mini-modules. For better understanding of how and where these defects originated and propagated, we have developed techniques where the current is limited during reverse-bias stressing. This allows for DLIT-based detection and detailedmore » studying of the region where breakdown is initiated before thermal runaway leads to permanent damage. Statistics of breakdown sites using current-limited conditions has allowed for reasonable identification of the as-grown defects where permanent breakdown will likely originate. Scanning electron microscope results and wormlike defect analysis show that breakdown originates in defects such as small pits, craters, or cracks in the CIGS layer, and the wormlike defects propagate near the top CIGS interface.« less

Identification and Analysis of Partial Shading Breakdown Sites in CuIn xGa (1-x)Se 2 Modules

DOE PAGES

Palmiotti, Elizabeth; Johnston, Steven; Gerber, Andreas; ...

2017-12-20

In this paper, CuIn xGa (1-x) (CIGS) mini-modules are stressed under reverse bias, resembling partial shading conditions, to predict and characterize where failures occur. Partial shading can cause permanent damage in the form of 'wormlike' defects on thin-film modules due to thermal runaway. This results in module-scale power losses. We have used dark lock-in thermography (DLIT) to spatially observe localized heating when reverse-bias breakdown occurs on various CIGS mini-modules. For better understanding of how and where these defects originated and propagated, we have developed techniques where the current is limited during reverse-bias stressing. This allows for DLIT-based detection and detailedmore » studying of the region where breakdown is initiated before thermal runaway leads to permanent damage. Statistics of breakdown sites using current-limited conditions has allowed for reasonable identification of the as-grown defects where permanent breakdown will likely originate. Scanning electron microscope results and wormlike defect analysis show that breakdown originates in defects such as small pits, craters, or cracks in the CIGS layer, and the wormlike defects propagate near the top CIGS interface.« less

Photovoltaic Manufacturing Consortium (PVMC) – Enabling America’s Solar Revolution

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

Metacarpa, David

The U.S. Photovoltaic Manufacturing Consortium (US-PVMC) is an industry-led consortium which was created with the mission to accelerate the research, development, manufacturing, field testing, commercialization, and deployment of next-generation solar photovoltaic technologies. Formed as part of the U.S. Department of Energy's (DOE) SunShot initiative, and headquartered in New York State, PVMC is managed by the State University of New York Polytechnic Institute (SUNY Poly) at the Colleges of Nanoscale Science and Engineering. PVMC is a hybrid of industry-led consortium and manufacturing development facility, with capabilities for collaborative and proprietary industry engagement. Through its technology development programs, advanced manufacturing development facilities,more » system demonstrations, and reliability and testing capabilities, PVMC has demonstrated itself to be a recognized proving ground for innovative solar technologies and system designs. PVMC comprises multiple locations, with the core manufacturing and deployment support activities conducted at the Solar Energy Development Center (SEDC), and the core Si wafering and metrology technologies being headed out of the University of Central Florida. The SEDC provides a pilot line for proof-of-concept prototyping, offering critical opportunities to demonstrate emerging concepts in PV manufacturing, such as evaluations of innovative materials, system components, and PV system designs. The facility, located in Halfmoon NY, encompasses 40,000 square feet of dedicated PV development space. The infrastructure and capabilities housed at PVMC includes PV system level testing at the Prototype Demonstration Facility (PDF), manufacturing scale cell & module fabrication at the Manufacturing Development Facility (MDF), cell and module testing, reliability equipment on its PV pilot line, all integrated with a PV performance database and analytical characterizations for PVMC and its partners test and commercial arrays. Additional development and deployment support are also housed at the SEDC, such as cost modeling and cost model based development activities for PV and thin film modules, components, and system level designs for reduced LCOE through lower installation hardware costs, labor reductions, soft costs and reduced operations and maintenance costs. The progression of the consortium activities started with infrastructure and capabilities build out focused on CIGS thin film photovoltaics, with a particular focus on flexible cell and module production. As marketplace changes and partners objectives shifted, the consortium shifted heavily towards deployment and market pull activities including Balance of System, cost modeling, and installation cost reduction efforts along with impacts to performance and DER operational costs. The consortium consisted of a wide array of PV supply chain companies from equipment and component suppliers through national developers and installers with a particular focus on commercial scale deployments (typically 25 to 2MW installations). With DOE funding ending after the fifth budget period, the advantages and disadvantages of such a consortium is detailed along with potential avenues for self-sustainability is reviewed.« less

Communication enabled – fast acting imbalance reserve (CE-FAIR)

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

Wilches-Bernal, Felipe; Concepcion, Ricky; Neely, Jason C.

This letter presents a new frequency control strategy that takes advantage of communications and fast responding resources like PV generation, energy storage, wind generation, and demand response, termed collectively as converter interfaced generators (CIGs). The proposed approach uses an active monitoring of power imbalances to rapidly redispatch CIGs. This approach differs from previously proposed frequency control schemes in that it employs feed-forward control based on a measured power imbalance rather that relying on a frequency measurement. As a result, time-domain simulations of the full Western Electricity Coordinating Council (WECC) system are conducted to demonstrate the effectiveness of the proposed method,more » showing improved performance.« less

Communication enabled – fast acting imbalance reserve (CE-FAIR)

DOE PAGES

Wilches-Bernal, Felipe; Concepcion, Ricky; Neely, Jason C.; ...

2017-06-08

This letter presents a new frequency control strategy that takes advantage of communications and fast responding resources like PV generation, energy storage, wind generation, and demand response, termed collectively as converter interfaced generators (CIGs). The proposed approach uses an active monitoring of power imbalances to rapidly redispatch CIGs. This approach differs from previously proposed frequency control schemes in that it employs feed-forward control based on a measured power imbalance rather that relying on a frequency measurement. As a result, time-domain simulations of the full Western Electricity Coordinating Council (WECC) system are conducted to demonstrate the effectiveness of the proposed method,more » showing improved performance.« less

Improved efficiency of a large-area Cu(In,Ga)Se₂ solar cell by a nontoxic hydrogen-assisted solid Se vapor selenization process.

PubMed

Wu, Tsung-Ta; Hu, Fan; Huang, Jyun-Hong; Chang, Chia-ho; Lai, Chih-chung; Yen, Yu-Ting; Huang, Hou-Ying; Hong, Hwen-Fen; Wang, Zhiming M; Shen, Chang-Hong; Shieh, Jia-Min; Chueh, Yu-Lun

2014-04-09

A nontoxic hydrogen-assisted solid Se vapor selenization process (HASVS) technique to achieve a large-area (40 × 30 cm(2)) Cu(In,Ga)Se2 (CIGS) solar panel with enhanced efficiencies from 7.1 to 10.8% (12.0% for active area) was demonstrated. The remarkable improvement of efficiency and fill factor comes from improved open circuit voltage (Voc) and reduced dark current due to (1) decreased interface recombination raised from the formation of a widened buried homojunction with n-type Cd(Cu) participation and (2) enhanced separation of electron and hole carriers resulting from the accumulation of Na atoms on the surface of the CIGS film. The effects of microstructural, compositional, and electrical characteristics with hydrogen-assisted Se vapor selenization, including interdiffusion of atoms and formation of buried homojunction, were examined in detail. This methodology can be also applied to CIS (CuInSe2) thin film solar cells with enhanced efficiencies from 5.3% to 8.5% (9.4% for active area) and provides a facile approach to improve quality of CIGS and stimulate the nontoxic progress in the large scale CIGS PV industry.

Interfacial Modifiers

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

Martin, Ina; French, Roger H.

Our project objective in the first and only Budget Period was to demonstrate the potential of nm-scale organofunctional silane coatings as a method of extending the lifetime of PV materials and devices. Specifically, the target was to double the lifetime performance of a laminated Cu(In,Ga)Se2 (CIGS) cell under real-world and accelerated aging exposure conditions. Key findings are that modification of aluminum-doped zinc oxide (AZO) films (materials used as transparent conductive oxide (TCO) top contacts) resulted in decreased degradation of optical and electrical properties under damp heat (DH) exposure compared to un-modified AZO. The most significant finding is that modification ofmore » the AZO top contact of full CIGS devices resulted in significantly improved properties under DH exposure compared to un-modified devices, by a factor of 4 after 1000 h. Results of this one-year project have demonstrated that surface functionalization is a viable pathway for extending the lifetime of state-of-the-art CIGS devices.« less

Activities of the task group 8 on thin film PV module reliability (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.

2016-09-01

Photovoltaic (PV) modules and systems are being used increasingly to provide renewable energy to schools, residences, small businesses and utilities. At this time, the home owners and small businesses have considerable difficulty in detecting module and/or system degradation and especially enforcing warranty. It needs to be noted that IEC 61215-1 (test req.), -2 (test proc.) and -1-1 (c-Si) are forecasted to be circulated end of Feb 2016 and only editorial changes would be possible. 61215 series does include thin film technologies and would be replacing 61646. Moreover, IEC 61215-1, section 7.2 power output and electric circuitry does contain significant changes to acceptance criteria regarding rated label values, particularly rated power. Even though it is believed that consensus could be achieved within IEC TC82 WG2, some of the smaller players that do not participate actively in IEC TC82 - may not be surprised and must be informed. The other tech specific parts 61215-1-2 (CdTe), -1-3 (a-Si, µc-Si) and -1-4 (CIS, CIGS) are out for comments. The IEC closing date was January 29, 2016. The additions alternative damp heat (DH) test proposed Solar Frontier is being reviewed. In the past, only 600 V systems were permitted in the grid-connected residential and commercial systems in the US. The US commercial systems can now use higher voltage (1,000-1500V) in order to reduce BOS component costs. It is believed that there would not be any problems. The Task Group 8 is collecting data on higher voltage systems.

Fabrication of nanostructured CIGS solar cells

NASA Astrophysics Data System (ADS)

Zhang, Hongwang; Wang, Fang; Parry, James; Perera, Samanthe; Zeng, Hao

2012-02-01

We present the work on Cu(In,Ga)(Se,S)2 based nanostructured solar cells based on nanowire arrays. CIGS as the light absorber for thin-film solar cells has been widely studied recently, due to its high absorption coefficient, long-term stability, and low-cost of fabrication. Recently, solution phase processed CIGS thin film solar cells attracted great attention due to their extremely low fabrication cost. However, the performance is lower than vacuum based thin films possibly due to higher density of defects and lower carrier mobility. On the other hand, one dimensional ordered nanostructures such as nanowires and nanorods can be used to make redial junction solar cells, where the orthogonality between light absorption and charge carrier separation can lead to enhanced PV performance. Since the charge carriers only need to traverse a short distance in the radial direction before they are separated at the heterojunction interface, the radial junction scheme can be more defect tolerant than their planar junction scheme. In this work, a wide band gap nanowire or nanotube array such as TiO2 is used as a scaffold where CIGS is conformally coated using solution phase to obtain a radial heterojunction solar cell. Their performance is compared that of the planar thin film solar cells fabricated with the same materials.

Improving Translation Models for Predicting the Energy Yield of Photovoltaic Power Systems. Cooperative Research and Development Final Report, CRADA Number CRD-13-526

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

Emery, Keith

2015-08-04

The project under this CRADA will analyze field data of various flat-plate and concentrator module technologies and cell measurements at the laboratory level. The field data will consist of current versus voltage data collected over many years on a latitude tilt test bed for Si, CdTe, amorphous silicon, and CIGS technologies. The concentrator data will be for mirror- and lens-based module designs using multijunction cells. The laboratory data will come from new measurements of cell performance with systematic variation of irradiance, temperature and spectral composition. These measurements will be labor-intensive and the aim will be to cover the widest possiblemore » parameter space for as many different PV samples as possible. The data analysis will require software tools to be developed. These tools will be customized for use with the specific NREL datasets and will be unsuitable for commercial release. The tools will be used to evaluate different translation equations against NREL outdoor datasets.« less

Supported PV module assembly

DOEpatents

Mascolo, Gianluigi; Taggart, David F.; Botkin, Jonathan D.; Edgett, Christopher S.

2013-10-15

A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

Evaluating the economic viability of CdTe/CIS and CIGS/CIS tandem photovoltaic modules

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

Nanayakkara, Sanjini U.; Horowitz, Kelsey; Kanevce, Ana

In this paper, we analyze the potential cost competitiveness of two frameless, glass–glass thin-film tandem photovoltaic module structures, cadmium telluride (CdTe)/CuInSe 2 (CIS) and CuIn 0.3Ga 0.7Se 2 (CIGS)/CIS, based on the demonstrated cost of manufacturing the respective component cell technologies in high volume. To consider multiple economic scenarios, we base the CdTe/CIS module efficiency on the current industrial production of CdTe modules, while for CIGS/CIS, we use an aspirational estimate for CIGS efficiency. We focus on four-terminal mechanically stacked structures, thus avoiding the need to achieve current matching between the two cells. The top cell in such a tandemmore » must have a transparent back contact, which has not been successfully implemented to date. However, for the purpose of understanding the economic viability of both tandems, we assume that this can be implemented at a cost similar to that of sputtered indium tin oxide. The cost of both tandem module structures was found to be nearly identical on an equal-area basis and approximately $30/m 2 higher than the single-junction alternatives. Both tandem modules are about 4% (absolute) more efficient than a module by using the top-cell material alone. We find that these tandem modules might reduce total system cost by as much as 11% in applications having a high area-related balance-of-system cost, such as area-constrained residential systems; however, the relative advantage of tandems decreases in the cases where balance-of-system costs are lower, such as in commercial and utility scale systems.« less

Evaluating the economic viability of CdTe/CIS and CIGS/CIS tandem photovoltaic modules

DOE PAGES

Nanayakkara, Sanjini U.; Horowitz, Kelsey; Kanevce, Ana; ...

2017-01-20

In this paper, we analyze the potential cost competitiveness of two frameless, glass–glass thin-film tandem photovoltaic module structures, cadmium telluride (CdTe)/CuInSe 2 (CIS) and CuIn 0.3Ga 0.7Se 2 (CIGS)/CIS, based on the demonstrated cost of manufacturing the respective component cell technologies in high volume. To consider multiple economic scenarios, we base the CdTe/CIS module efficiency on the current industrial production of CdTe modules, while for CIGS/CIS, we use an aspirational estimate for CIGS efficiency. We focus on four-terminal mechanically stacked structures, thus avoiding the need to achieve current matching between the two cells. The top cell in such a tandemmore » must have a transparent back contact, which has not been successfully implemented to date. However, for the purpose of understanding the economic viability of both tandems, we assume that this can be implemented at a cost similar to that of sputtered indium tin oxide. The cost of both tandem module structures was found to be nearly identical on an equal-area basis and approximately $30/m 2 higher than the single-junction alternatives. Both tandem modules are about 4% (absolute) more efficient than a module by using the top-cell material alone. We find that these tandem modules might reduce total system cost by as much as 11% in applications having a high area-related balance-of-system cost, such as area-constrained residential systems; however, the relative advantage of tandems decreases in the cases where balance-of-system costs are lower, such as in commercial and utility scale systems.« less

Nanosecond laser scribing of CIGS thin film solar cell based on ITO bottom contact

NASA Astrophysics Data System (ADS)

Kuk, Seungkuk; Wang, Zhen; Fu, Shi; Zhang, Tao; Yu, Yi Yin; Choi, JaeMyung; Jeong, Jeung-hyun; Hwang, David J.

2018-03-01

Cu(In,Ga)Se2 (CIGS) thin films, a promising photovoltaic architecture, have mainly relied on Molybdenum for the bottom contact. However, the opaque nature of Molybdenum (Mo) poses limitations in module level fabrication by laser scribing as a preferred method for interconnect. We examined the P1, P2, and P3 laser scribing processes on CIGS photovoltaic architecture on the indium tin oxide (ITO) bottom contact with a cost-effective nanosecond pulsed laser of 532 nm wavelength. Laser illuminated from the substrate side, enabled by the transparent bottom contact, facilitated selective laser energy deposition onto relevant interfaces towards high-quality scribing. Parametric tuning procedures are described in conjunction with experimental and numerical investigation of relevant mechanisms, and preliminary mini-module fabrication results are also presented.

PV module mounting method and mounting assembly

DOEpatents

Lenox, Carl J.S.; Johnson, Kurt M.

2013-04-23

A method for mounting PV modules to a deck includes selecting PV module layout pattern so that adjacent PV module edges are spaced apart. PV mounting and support assemblies are secured to the deck according to the layout pattern using fasteners extending into the deck. The PV modules are placed on the PV mounting and support assemblies. Retaining elements are located over and secured against the upper peripheral edge surfaces of the PV modules so to secure them to the deck with the peripheral edges of the PV modules spaced apart from the deck. In some examples a PV module mounting assembly, for use on a shingled deck, comprises flashing, a base mountable on the flashing, a deck-penetrating fastener engageable with the base and securable to the deck so to secure the flashing and the base to the shingled deck, and PV module mounting hardware securable to the base.

Ballasted photovoltaic module and module arrays

DOEpatents

Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA

2011-11-29

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

Solution-deposited CIGS thin films for ultra-low-cost photovoltaics

NASA Astrophysics Data System (ADS)

Eldada, Louay A.; Hersh, Peter; Stanbery, Billy J.

2010-09-01

We describe the production of photovoltaic modules with high-quality large-grain copper indium gallium selenide (CIGS) thin films obtained with the unique combination of low-cost ink-based precursors and a reactive transfer printing method. The proprietary metal-organic inks contain a variety of soluble Cu-, In- and Ga- multinary selenide materials; they are called metal-organic decomposition (MOD) precursors, as they are designed to decompose into the desired precursors. Reactive transfer is a two-stage process that produces CIGS through the chemical reaction between two separate precursor films, one deposited on the substrate and the other on a printing plate in the first stage. In the second stage, these precursors are rapidly reacted together under pressure in the presence of heat. The use of two independent thin films provides the benefits of independent composition and flexible deposition technique optimization, and eliminates pre-reaction prior to the synthesis of CIGS. In a few minutes, the process produces high quality CIGS films, with large grains on the order of several microns, and preferred crystallographic orientation, as confirmed by compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 14% and module efficiencies of 12% were achieved using this method. The atmospheric deposition processes include slot die extrusion coating, ultrasonic atomization spraying, pneumatic atomization spraying, inkjet printing, direct writing, and screen printing, and provide low capital equipment cost, low thermal budget, and high throughput.

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

Horowitz, Kelsey A. W.; Fu, Ran; Woodhouse, Michael

This article examines current cost drivers and potential avenues to reduced cost for monolithic, glass-glass Cu(In,Ga)(Se,S)2 (CIGS) modules by constructing a comprehensive bottom-up cost model. For a reference case where sputtering plus batch sulfurization after selenization (SAS) is employed, we compute a manufacturing cost of $69/m2 if the modules are made in the United States at a 1 GW/year production volume. At 14% module efficiency, this corresponds to a manufacturing cost of $0.49/WDC and a minimum sustainable price (MSP) of $0.67/WDC. We estimate that MSP could vary within +/-20% of this value given the range of quoted input prices, andmore » existing variations in module design, manufacturing processes, and manufacturing location. Potential for reduction in manufacturing costs to below $0.40/WDC may be possible if average production module efficiencies can be increased above 17% without increasing $/m2 costs; even lower costs could be achieved if $/m2 costs could be reduced, particularly via innovations in the CIGS deposition process or balance-of-module elements. We present the impact on cost of regional factors, CIGS deposition method, device design, and price fluctuations. One metric of competitiveness-levelized cost of energy (LCOE) -- is also assessed for several U.S. locations and compared to that of standard multi-crystalline silicon (m(c-Si)) and cadmium telluride (CdTe).« less

Electrodeposition of ZnO-doped films as window layer for Cd-free CIGS-based solar cells

NASA Astrophysics Data System (ADS)

Tsin, Fabien; Vénérosy, Amélie; Hildebrandt, Thibaud; Hariskos, Dimitrios; Naghavi, Negar; Lincot, Daniel; Rousset, Jean

2016-02-01

The Cu(In,Ga)Se2 (CIGS) thin film solar cell technology has made a steady progress within the last decade reaching efficiency up to 22.3% on laboratory scale, thus overpassing the highest efficiency for polycrystalline silicon solar cells. High efficiency CIGS modules employ a so-called buffer layer of cadmium sulfide CdS deposited by Chemical Bath Deposition (CBD), which presence and Cd-containing waste present some environmental concerns. A second potential bottleneck for CIGS technology is its window layer made of i-ZnO/ZnO:Al, which is deposited by sputtering requiring expensive vacuum equipment. A non-vacuum deposition of transparent conductive oxide (TCO) relying on simpler equipment with lower investment costs will be more economically attractive, and could increase competitiveness of CIGS-based modules with the mainstream silicon-based technologies. In the frame of Novazolar project, we have developed a low-cost aqueous solution photo assisted electrodeposition process of the ZnO-based window layer for high efficiency CIGS-based solar cells. The window layer deposition have been first optimized on classical CdS buffer layer leading to cells with efficiencies similar to those measured with the sputtered references on the same absorber (15%). The the optimized ZnO doped layer has been adapted to cadmium free devices where the CdS is replaced by chemical bath deposited zinc oxysulfide Zn(S,O) buffer layer. The effect of different growth parameters has been studied on CBD-Zn(S,O)-plated co-evaporated Cu(In,Ga)Se2 substrates provided by the Zentrum für Sonnenenergie-und Wasserstoff-Forschung (ZSW). This optimization of the electrodeposition of ZnO:Cl on CIGS/Zn(S,O) stacks led to record efficiency of 14%, while the reference cell with a sputtered (Zn,Mg)O/ZnO:Al window layer has an efficiency of 15.2%.

PV Module Reliability Workshop | Photovoltaic Research | NREL

Science.gov Websites

-year old PV system in Quebec, Canada-Alex Bradley, Tanya Dhir, Yves Poissant Solar panel design factors PV Module Reliability Workshop PV Module Reliability Workshop Tuesday, February 24, 2015 Chair : Michael Kempe The 2015 PV Module Reliability Workshop (PVMRW) continued in the tradition of this annual

I-V Curves from Photovoltaic Modules Deployed in Tucson

NASA Astrophysics Data System (ADS)

Kopp, Emily; Brooks, Adria; Lonij, Vincent; Cronin, Alex

2011-10-01

More than 30 Mega Watts of photo-voltaic (PV) modules are connected to the electric power grid in Tucson, AZ. However, predictions of PV system electrical yields are uncertain, in part because PV modules degrade at various rates (observed typically in the range 0% to 3 %/yr). We present I-V curves (PV output current as a function of PV output voltage) as a means to study PV module efficiency, de-ratings, and degradation. A student-made I-V curve tracer for 100-Watt modules will be described. We present I-V curves for several different PV technologies operated at an outdoor test yard, and we compare new modules to modules that have been operated in the field for 10 years.

Apparatuses to support photovoltaic modules

DOEpatents

Ciasulli, John; Jones, Jason

2017-08-22

Methods and apparatuses to support photovoltaic ("PV") modules are described. A saddle bracket has a mounting surface to support one or more PV modules over a tube, a gusset coupled to the mounting surface, and a mounting feature coupled to the gusset to couple to the tube. A grounding washer has a first portion to couple to a support; and a second portion coupled to the first portion to provide a ground path to a PV module. A PV system has a saddle bracket; a PV module over the saddle bracket; and a grounding washer coupled to the saddle bracket and the PV module. Saddle brackets can be coupled to a torque tube at predetermined locations. PV modules can be coupled to the saddle brackets.

Pressure-equalizing PV assembly and method

DOEpatents

Dinwoodie, Thomas L.

2004-10-26

Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

Understanding the cell-to-module efficiency gap in Cu(In,Ga)(S,Se)2 photovoltaics scale-up

NASA Astrophysics Data System (ADS)

Bermudez, Veronica; Perez-Rodriguez, Alejandro

2018-06-01

Cu(In,Ga)(S,Se)2 (CIGS) solar cells show record efficiencies comparable to those of crystalline Si-based technologies. Their industrial module production costs are also comparable to those of Si photovoltaics in spite of their much lower production volume. However, the competitiveness of CIGS is compromised by the difference in performance between cell and module scales, known as the cell-to-module efficiency gap, which is significantly higher than in competing industrial photovoltaic technologies. In this Review, we quantify the main cell-to-module efficiency loss mechanisms and discuss the various strategies explored in academia and industry to reduce the efficiency gap: new transparent conductive oxides, hybrid modularization approaches and the use of wide-bandgap solar absorbers in the 1.4-1.5 eV range. To implement these strategies, research gaps relating to various device layers need to be filled.

On enhancing energy harvesting performance of the photovoltaic modules using an automatic cooling system and assessing its economic benefits of mitigating greenhouse effects on the environment

NASA Astrophysics Data System (ADS)

Wang, Jen-Cheng; Liao, Min-Sheng; Lee, Yeun-Chung; Liu, Cheng-Yue; Kuo, Kun-Chang; Chou, Cheng-Ying; Huang, Chen-Kang; Jiang, Joe-Air

2018-02-01

The performance of photovoltaic (PV) modules under outdoor operation is greatly affected by their location and environmental conditions. The temperature of a PV module gradually increases as it is exposed to solar irradiation, resulting in degradation of its electrical characteristics and power generation efficiency. This study adopts wireless sensor network (WSN) technology to develop an automatic water-cooling system for PV modules in order to improve their PV power generation efficiency. A temperature estimation method is developed to quickly and accurately estimate the PV module temperatures based on weather data provided from the WSN monitoring system. Further, an estimation method is also proposed for evaluation of the electrical characteristics and output power of the PV modules, which is performed remotely via a control platform. The automatic WSN-based water-cooling mechanism is designed to avoid the PV module temperature from reaching saturation. Equipping each PV module with the WSN-based cooling system, the ambient conditions are monitored automatically so that the temperature of the PV module is controlled by sprinkling water on the panel surface. The field-test experiment results show an increase in the energy harvested by the PV modules of approximately 17.75% when using the proposed WSN-based cooling system.

Environmental Impacts from Photovoltaic Solar Cells Made with Single Walled Carbon Nanotubes.

PubMed

Celik, Ilke; Mason, Brooke E; Phillips, Adam B; Heben, Michael J; Apul, Defne

2017-04-18

An ex-ante life cycle inventory was developed for single walled carbon nanotube (SWCNT) PV cells, including a laboratory-made 1% efficient device and an aspirational 28% efficient four-cell tandem device. The environmental impact of unit energy generation from the mono-Si PV technology was used as a reference point. Compared to monocrystalline Si (mono-Si), the environmental impacts from 1% SWCNT was ∼18 times higher due mainly to the short lifetime of three years. However, even with the same short lifetime, the 28% cell had lower environmental impacts than mono-Si. The effects of lifetime and efficiency on the environmental impacts were further examined. This analysis showed that if the SWCNT device efficiency had the same value as the best efficiency of the material under comparison, to match the total normalized impacts of the mono- and poly-Si, CIGS, CdTe, and a-Si devices, the SWCNT devices would need a lifetime of 2.8, 3.5, 5.3, 5.1, and 10.8 years, respectively. It was also found that if the SWCNT PV has an efficiency of 4.5% or higher, its energy payback time would be lower than other existing and emerging PV technologies. The major impacts of SWCNT PV came from the cell's materials synthesis.

Numerical investigation of the thermal and electrical performances for combined solar photovoltaic/thermal (PV/T) modules based on internally extruded fin flow channel

NASA Astrophysics Data System (ADS)

Deng, Y. C.; Li, Q. P.; Wang, G. J.

2017-11-01

A solar photovoltaic/thermal (PV/T) module based on internally extruded fin flow channel was investigated numerically in this paper. First of all, the structures of the thin plate heat exchanger and the PV/T module were presented. Then, a numerical model of the PV/T module considering solar irradiation, fluid flow and heat transfer was developed to analyze the performance of the module. Finally, the steady electrical and thermal efficiencies of the PV/T module at different inlet water temperatures and mass flow rates were achieved. These numerical results supply theory basis for practical application of the PV/T module.

Performance degradation of photovoltaic modules at different sites

NASA Astrophysics Data System (ADS)

Arab, A. Hadj; Mahammed, I. Hadj; Ould Amrouche, S.; Taghezouit, B.; Yassaa, N.

2018-05-01

In this work are presented results of electrical performance measurements of 120 crystalline silicon PV modules following long-term outdoor measurements. A set of 90 PV modules represent the first grid-connected photovoltaic (PV) system in Algeria, installed at the level of the “Centre de Développement des Energies Renouvelables” (CDER) site (Mediterranean coast), Bouzareah. The other 30 PV modules were undertaken in an arid area of the desert region of Ghardaïa site, about 600 km south of Algiers, with measurements collected from different applications. Following different characterization tests, we noticed that the all tested PV modules kept their power-generating rate except a slight reduction. Therefore, a mathematical model has been used to carry out PV module testing at different irradiance and temperature levels. Hence, different PV module parameters have been calculated from the recorded values of the open-circuit voltage, the short-circuit current, the voltage and current at maximum power point. The electrical measurements have indicated different degradations of current-voltage parameters. All the PV modules stated a decrease in the nominal power, which is variable from one module to another.

Pressure equalizing photovoltaic assembly and method

DOEpatents

Dinwoodie, Thomas L [Piedmont, CA

2003-05-27

Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the peripheral edge of the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions

PubMed Central

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C.

2015-01-01

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper. PMID:26230694

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions.

PubMed

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C

2015-07-29

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper.

A Practical Irradiance Model for Bifacial PV Modules

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

Marion, Bill; MacAlpine, Sara; Deline, Chris

2017-06-21

A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be added tomore » the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using ray tracing software.« less

A Practical Irradiance Model for Bifacial PV Modules: Preprint

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

Marion, Bill; MacAlpine, Sara; Deline, Chris

2017-06-15

A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors (CFs) to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be addedmore » to the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using the RADIANCE ray tracing program.« less

Wind effect on PV module temperature: Analysis of different techniques for an accurate estimation.

NASA Astrophysics Data System (ADS)

Schwingshackl, Clemens; Petitta, Marcello; Ernst Wagner, Jochen; Belluardo, Giorgio; Moser, David; Castelli, Mariapina; Zebisch, Marc; Tetzlaff, Anke

2013-04-01

In this abstract a study on the influence of wind to model the PV module temperature is presented. This study is carried out in the framework of the PV-Alps INTERREG project in which the potential of different photovoltaic technologies is analysed for alpine regions. The PV module temperature depends on different parameters, such as ambient temperature, irradiance, wind speed and PV technology [1]. In most models, a very simple approach is used, where the PV module temperature is calculated from NOCT (nominal operating cell temperature), ambient temperature and irradiance alone [2]. In this study the influence of wind speed on the PV module temperature was investigated. First, different approaches suggested by various authors were tested [1], [2], [3], [4], [5]. For our analysis, temperature, irradiance and wind data from a PV test facility at the airport Bolzano (South Tyrol, Italy) from the EURAC Institute of Renewable Energies were used. The PV module temperature was calculated with different models and compared to the measured PV module temperature at the single panels. The best results were achieved with the approach suggested by Skoplaki et al. [1]. Preliminary results indicate that for all PV technologies which were tested (monocrystalline, amorphous, microcrystalline and polycrystalline silicon and cadmium telluride), modelled and measured PV module temperatures show a higher agreement (RMSE about 3-4 K) compared to standard approaches in which wind is not considered. For further investigation the in-situ measured wind velocities were replaced with wind data from numerical weather forecast models (ECMWF, reanalysis fields). Our results show that the PV module temperature calculated with wind data from ECMWF is still in very good agreement with the measured one (R² > 0.9 for all technologies). Compared to the previous analysis, we find comparable mean values and an increasing standard deviation. These results open a promising approach for PV module temperature estimation using meteorological parameters. References: [1] Skoplaki, E. et al., 2008: A simple correlation for the operating temperature of photovoltaic modules of arbitrary mounting, Solar Energy Materials & Solar Cells 92, 1393-1402 [2] Skoplaki, E. et al., 2008: Operating temperature of photovoltaic modules: A survey of pertinent correlations, Renewable Energy 34, 23-29 [3] Koehl, M. et al., 2011: Modeling of the nominal operating cell temperature based on outdoor weathering, Solar Energy Materials & Solar Cells 95, 1638-1646 [4] Mattei, M. et al., 2005: Calculation of the polycrystalline PV module temperature using a simple method of energy balance, Renewable Energy 31, 553-567 [5] Kurtz, S. et al.: Evaluation of high-temperature exposure of rack-mounted photovoltaic modules

Potential-induced degradation in photovoltaic modules: a critical review

DOE PAGES

Luo, Wei; Khoo, Yong Sheng; Hacke, Peter; ...

2016-11-21

Potential-induced degradation (PID) has received considerable attention in recent years due to its detrimental impact on photovoltaic (PV) module performance under field conditions. Both crystalline silicon (c-Si) and thin-film PV modules are susceptible to PID. While extensive studies have already been conducted in this area, the understanding of the PID phenomena is still incomplete and it remains a major problem in the PV industry. Herein, a critical review of the available literature is given to serve as a one-stop source for understanding the current status of PID research. This article also aims to provide an overview of future research pathsmore » to address PID-related issues. This paper consists of three parts. In the first part, the modelling of leakage current paths in the module package is discussed. The PID mechanisms in both c-Si and thin-film PV modules are also comprehensively reviewed. The second part summarizes various test methods to evaluate PV modules for PID. The last part focuses on studies related to PID in the omnipresent p-type c-Si PV modules. The dependence of temperature, humidity and voltage on the progression of PID is examined. Preventive measures against PID at the cell, module and system levels are illustrated. Moreover, PID recovery in standard p-type c-Si PV modules is also studied. Most of the findings from p-type c-Si PV modules are also applicable to other PV module technologies.« less

Simulation, measurement, and emulation of photovoltaic modules using high frequency and high power density power electronic circuits

NASA Astrophysics Data System (ADS)

Erkaya, Yunus

The number of solar photovoltaic (PV) installations is growing exponentially, and to improve the energy yield and the efficiency of PV systems, it is necessary to have correct methods for simulation, measurement, and emulation. PV systems can be simulated using PV models for different configurations and technologies of PV modules. Additionally, different environmental conditions of solar irradiance, temperature, and partial shading can be incorporated in the model to accurately simulate PV systems for any given condition. The electrical measurement of PV systems both prior to and after making electrical connections is important for attaining high efficiency and reliability. Measuring PV modules using a current-voltage (I-V) curve tracer allows the installer to know whether the PV modules are 100% operational. The installed modules can be properly matched to maximize performance. Once installed, the whole system needs to be characterized similarly to detect mismatches, partial shading, or installation damage before energizing the system. This will prevent any reliability issues from the onset and ensure the system efficiency will remain high. A capacitive load is implemented in making I-V curve measurements with the goal of minimizing the curve tracer volume and cost. Additionally, the increase of measurement resolution and accuracy is possible via the use of accurate voltage and current measurement methods and accurate PV models to translate the curves to standard testing conditions. A move from mechanical relays to solid-state MOSFETs improved system reliability while significantly reducing device volume and costs. Finally, emulating PV modules is necessary for testing electrical components of a PV system. PV emulation simplifies and standardizes the tests allowing for different irradiance, temperature and partial shading levels to be easily tested. Proper emulation of PV modules requires an accurate and mathematically simple PV model that incorporates all known system variables so that any PV module can be emulated as the design requires. A non-synchronous buck converter is proposed for the emulation of a single, high-power PV module using traditional silicon devices. With the proof-of-concept working and improvements in efficiency, power density and steady-state errors made, dynamic tests were performed using an inverter connected to the PV emulator. In order to improve the dynamic characteristics, a synchronous buck converter topology is proposed along with the use of advanced GaNFET devices which resulted in very high power efficiency and improved dynamic response characteristics when emulating PV modules.

Photovoltaic Module Reliability Workshop 2011: February 16-17, 2011

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

Kurtz, S.

2013-11-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Photovoltaic Module Reliability Workshop 2014: February 25-26, 2014

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

Kurtz, S.

2014-02-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Photovoltaic Module Reliability Workshop 2013: February 26-27, 2013

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

Kurtz, S.

2013-10-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Photovoltaic Module Reliability Workshop 2010: February 18-19, 2010

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

Kurtz, J.

2013-11-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

2016 NREL Photovoltaic Module Reliability Workshop

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

Kurtz, Sarah

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology - both critical goals for moving PV technologies deeper into the electricity marketplace.

2015 NREL Photovoltaic Module Reliability Workshops

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

Kurtz, Sarah

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Multi-position photovoltaic assembly

DOEpatents

Dinwoodie, Thomas L.

2003-03-18

The invention is directed to a PV assembly, for use on a support surface, comprising a base, a PV module, a multi-position module support assembly, securing the module to the base at shipping and inclined-use angles, a deflector, a multi-position deflector support securing the deflector to the base at deflector shipping and deflector inclined-use angles, the module and deflector having opposed edges defining a gap therebetween. The invention permits transport of the PV assemblies in a relatively compact form, thus lowering shipping costs, while facilitating installation of the PV assemblies with the PV module at the proper inclination.

High efficiency copper indium gallium diselenide (CIGS) thin film solar cells

NASA Astrophysics Data System (ADS)

Rajanikant, Ray Jayminkumar

The generation of electrical current from the solar radiation is known as the photovoltaic effect. Solar cell, also known as photovoltaic (PV) cell, is a device that works on the principle of photovoltaic effect, and is widely used for the generation of electricity. Thin film polycrystalline solar cells based on copper indium gallium diselenide (CIGS) are admirable candidates for clean energy production with competitive prices in the near future. CIGS based polycrystalline thin film solar cells with efficiencies of 20.3 % and excellent temperature stability have already been reported at the laboratory level. The present study discusses about the fabrication of CIGS solar cell. Before the fabrication part of CIGS solar cell, a numerical simulation is carried out using One-Dimensional Analysis of Microelectronic and Photonic Structures (AMPS-ID) for understanding the physics of a solar cell device, so that an optimal structure is analyzed. In the fabrication part of CIGS solar cell, Molybdenum (Mo) thin film, which acts as a 'low' resistance metallic back contact, is deposited by RF magnetron sputtering on organically cleaned soda lime glass substrate. The major advantages for using Mo are high temperature, (greater than 600 °C), stability and inertness to CIGS layer (i.e., no diffusion of CIGS into Mo). Mo thin film is deposited at room temperature (RT) by varying the RF power and the working pressure. The Mo thin films deposited with 100 W RF power and 1 mTorr working pressure show a reflectivity of above average 50 % and the low sheet resistance of about 1 O/□. The p-type CIGS layer is deposited on Mo. Before making thin films of CIGS, a powder of CIGS material is synthesized using melt-quenching method. Thin films of CIGS are prepared by a single-stage flash evaporation process on glass substrates, initially, for optimization of deposition parameters and than on Mo coated glass substrates for device fabrication. CIGS thin film is deposited at 250 °C at a pressure of 10-5 mbar. The thickness of the film was kept 1 mum for the solar cell device preparation. Rapid Thermal Annealing (RTA) is carried out of CIGS thin film at 500 °C for 2 minutes in the argon atmosphere. Annealing process mainly improves the grain growth of the CIGS and, hence the surface roughness, which is essential for a multilayered semiconductor structure. Thin layer of n-type highly resistive cadmium sulphide (CdS), generally known as a "buffer" layer, is deposited on CIGS layer by thermal and flash evaporation method at the substrate temperature of 100 °C. The CdS thin film plays a crucial role in the formation of the p-n junction and thus the solar cell device performance. The effect of CdS film substrate temperature ranging from 50 °C to 200 °C is observed. At the 100 °C substrate temperature, CdS thin film shows the near to 85 % of transmission in the visible region and resistivity of the order of greater then 20 x 109 Ocm, which are the essential characteristics of buffer layer. The bi-layer structure of ZnO, containing 70 nm i-ZnO and 500 nm aluminum (Al) doped ZnO, act as a transparent front-contact for CIGS thin film solar cell. These layers were deposited using RF magnetron sputtering. i-ZnO thin film acts as an insulating layer, which prevents the recombination of the photo-generated carries and also minimizes the lattice miss match defects between CdS and Al-ZnO. The resistivity of iZnO and Al-ZnO is of the order of 1012 Ocm and 10-4 Ocm, respectively. Al-ZnO thin films act as transparent conducting top electrode having transparency of about 85 % in the visible region. On Al-ZnO layer the finger-type grid pattern of silver (Ag), 200 nm thick, is deposited for the collection of photo-generated carriers. The thin film based multilayered structure Mo / CIGS / CdS / i-ZnO / Al-ZnO / Ag grid of CIGS solar cell is grown one by one on a single glass substrate. As-prepared CIGS solar cell device shows a minute photovoltaic effect. For the further improvement of the cell we have varied the thickness of the buffer layer i.e. CdS. In addition, the deposition of CdS is carried out using flash evaporation method to improve the CIGS/CdS junction. Heat soak pulses of about 200 °C are also applied for 20 sec for the further upgrading the junction. To protect the CIGS/CdS junction from the high-energy sputtered particles of ZnO, a fine mesh of stainless steel is placed just before the sample holder to enhance the performance of the solar cell. The influence of the thickness of iZnO and CdS has been checked. The maximum V oe and Jsc of about 138 mV and 1.3 mA/cm2 , respectively, are achieved using flash evaporated CIGS layer and flash evaporated CdS thin film. Further improvement of current performance can be done either by adopting some other fabrication method to obtain a denser CIGS absorber layer or replacing the CdS layer with some other efficient buffer layer.

Photovoltaic Module Reliability Workshop 2012: February 28 - March 1, 2012

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

Kurtz, S.

2013-11-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Integrated application of combined cooling, heating and power poly-generation PV radiant panel system of zero energy buildings

NASA Astrophysics Data System (ADS)

Yin, Baoquan

2018-02-01

A new type of combined cooling, heating and power of photovoltaic radiant panel (PV/R) module was proposed, and applied in the zero energy buildings in this paper. The energy system of this building is composed of PV/R module, low temperature difference terminal, energy storage, multi-source heat pump, energy balance control system. Radiant panel is attached on the backside of the PV module for cooling the PV, which is called PV/R module. During the daytime, the PV module was cooled down with the radiant panel, as the temperature coefficient influence, the power efficiency was increased by 8% to 14%, the radiant panel solar heat collecting efficiency was about 45%. Through the nocturnal radiant cooling, the PV/R cooling capacity could be 50 W/m2. For the multifunction energy device, the system shows the versatility during the heating, cooling and power used of building utilization all year round.

PV_LIB Toolbox v. 1.3

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

2015-12-09

PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV system's plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

An Illumination- and Temperature-Dependent Analytical Model for Copper Indium Gallium Diselenide (CIGS) Solar Cells

DOE PAGES

Sun, Xingshu; Silverman, Timothy; Garris, Rebekah; ...

2016-07-18

In this study, we present a physics-based analytical model for copper indium gallium diselenide (CIGS) solar cells that describes the illumination- and temperature-dependent current-voltage (I-V) characteristics and accounts for the statistical shunt variation of each cell. The model is derived by solving the drift-diffusion transport equation so that its parameters are physical and, therefore, can be obtained from independent characterization experiments. The model is validated against CIGS I-V characteristics as a function of temperature and illumination intensity. This physics-based model can be integrated into a large-scale simulation framework to optimize the performance of solar modules, as well as predict themore » long-term output yields of photovoltaic farms under different environmental conditions.« less

Timothy Silverman | NREL

Science.gov Websites

physical phenomena, PV package reliability, and outdoor PV performance. At NREL, he performs research in advanced concept PV modules. Dr. Silverman studies the performance and reliability of PV modules, including previously studied the degradation of solder joints in high-concentration PV and the outdoor performance of

Peter Hacke | NREL

Science.gov Websites

photovoltaic (PV) modules, inspections for root cause of module failures in the field, and accelerated lifetime delamination. His research interests are in modeling of degradation processes of PV modules, module integrated analysis of PV degradation data. He also explores accelerated multi-stress and combined stress testing to

Georgetown University Photovoltaic Higher Education National Exemplar Facility (PHENEF)

NASA Technical Reports Server (NTRS)

Marshall, N.

1984-01-01

Several photographs of this facility using photovoltaic (PV) cells are shown. An outline is given of the systems requirements, system design and wiring topology, a simplified block design, module electrical characteristics, PV module and PV module matching.

77 FR 63791 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled into Modules, from the People's...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-17

...., Jiangsu Sunlink PV Technology Co., Ltd., and JA Solar Technology Yangzhou Co., Ltd. On June 25, 2012, Wuxi... (Chengdu) PV Tianwei New Energy 25.96 Module Co., Ltd. (Chengdu) PV Module Co., Ltd. Canadian Solar.... Chint Solar (Zhejiang) Co., Ltd Chint Solar (Zhejiang) 25.96 Co., Ltd. Suzhou Shenglong PV-Tech Co...

A hybrid life-cycle inventory for multi-crystalline silicon PV module manufacturing in China

NASA Astrophysics Data System (ADS)

Yao, Yuan; Chang, Yuan; Masanet, Eric

2014-11-01

China is the world’s largest manufacturer of multi-crystalline silicon photovoltaic (mc-Si PV) modules, which is a key enabling technology in the global transition to renewable electric power systems. This study presents a hybrid life-cycle inventory (LCI) of Chinese mc-Si PV modules, which fills a critical knowledge gap on the environmental implications of mc-Si PV module manufacturing in China. The hybrid LCI approach combines process-based LCI data for module and poly-silicon manufacturing plants with a 2007 China IO-LCI model for production of raw material and fuel inputs to estimate ‘cradle to gate’ primary energy use, water consumption, and major air pollutant emissions (carbon dioxide, methane, sulfur dioxide, nitrous oxide, and nitrogen oxides). Results suggest that mc-Si PV modules from China may come with higher environmental burdens that one might estimate if one were using LCI results for mc-Si PV modules manufactured elsewhere. These higher burdens can be reasonably explained by the efficiency differences in China’s poly-silicon manufacturing processes, the country’s dependence on highly polluting coal-fired electricity, and the expanded system boundaries associated with the hybrid LCI modeling framework. The results should be useful for establishing more conservative ranges on the potential ‘cradle to gate’ impacts of mc-Si PV module manufacturing for more robust LCAs of PV deployment scenarios.

Photovoltaic module with removable wind deflector

DOEpatents

Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA; Culligan, Matthew [Berkeley, CA

2012-08-07

A photovoltaic (PV) module assembly including a PV module, a deflector, and a clip. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes a support arm forming a seat. The deflector defines a front face and a rear face, with the clip extending from either the trailing frame member or the rear face of the deflector. In a mounted state, the deflector is nested within the seat and is releasably mounted to the trailing frame member via the clip. In some embodiments, the support arm forms a second seat, with the PV module assembly providing a second mounted state in which the deflector is in a differing orientation/slope, nested within the second seat and releasably mounted to the trailing frame member via the clip.

Photovoltaic module with removable wind deflector

DOEpatents

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

2014-02-18

A photovoltaic (PV) module assembly including a PV module, a deflector, and a clip. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes a support arm forming a seat. The deflector defines a front face and a rear face, with the clip extending from either the trailing frame member or the rear face of the deflector. In a mounted state, the deflector is nested within the seat and is releasably mounted to the trailing frame member via the clip. In some embodiments, the support arm forms a second seat, with the PV module assembly providing a second mounted state in which the deflector is in a differing orientation/slope, nested within the second seat and releasably mounted to the trailing frame member via the clip.

Photovoltaic module with removable wind deflector

DOEpatents

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

2013-05-28

A photovoltaic (PV) module assembly including a PV module, a deflector, and a clip. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes a support arm forming a seat. The deflector defines a front face and a rear face, with the clip extending from either the trailing frame member or the rear face of the deflector. In a mounted state, the deflector is nested within the seat and is releasably mounted to the trailing frame member via the clip. In some embodiments, the support arm forms a second seat, with the PV module assembly providing a second mounted state in which the deflector is in a differing orientation/slope, nested within the second seat and releasably mounted to the trailing frame member via the clip.

Passive thermal regulation of flat PV modules by coupling the mechanisms of evaporative and fin cooling

NASA Astrophysics Data System (ADS)

Chandrasekar, M.; Senthilkumar, T.

2016-07-01

A passive thermal regulation technique with fins in conjunction with cotton wicks is developed in the present work for controlling the temperature of PV module during its operation. Experiments were conducted with the developed technique in the location of Tiruchirappalli (78.6°E and 10.8°N), Tamil Nadu, India with flat 25 Wp PV module and its viability was confirmed. The PV module temperature got reduced by 12 % while the electrical yield is increased by 14 % with the help of the developed cooling system. Basic energy balance equation applicable for PV module was used to evaluate the module temperatures and a fair agreement was obtained between the theoretical and experimental values for the cases of with cooling and without cooling.

Compendium of photovoltaic degradation rates: Photovoltaic degradation rates

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

Jordan, Dirk C.; Kurtz, Sarah R.; VanSant, Kaitlyn

Published data on photovoltaic (PV) degradation measurements were aggregated and re-examined. The subject has seen an increased interest in recent years resulting in more than 11 000 degradation rates in almost 200 studies from 40 different countries. As studies have grown in number and size, we found an impact from sampling bias attributable to size and accuracy. Because of the correlational nature of this study we examined the data in several ways to minimize this bias. We found median degradation for x-Si technologies in the 0.5-0.6%/year range with the mean in the 0.8-0.9%/year range. Hetero-interface technology (HIT) and microcrystalline siliconmore » (..mu..c-Si) technologies, although not as plentiful, exhibit degradation around 1%/year and resemble thin-film products more closely than x-Si. Several studies showing low degradation for copper indium gallium selenide (CIGS) have emerged. Higher degradation for cadmium telluride (CdTe) has been reported, but these findings could reflect a convolution of less accurate studies and longer stabilization periods for some products. Significant deviations for beginning-of-life measurements with respect to nameplate rating have been documented over the last 35 years. Therefore, degradation rates that use nameplate rating as reference may be significantly impacted. Studies that used nameplate rating as reference but used solar simulators showed less variation than similar studies using outdoor measurements, even when accounting for different climates. This could be associated with confounding effects of measurement uncertainty and soiling that take place outdoors. Hotter climates and mounting configurations that lead to sustained higher temperatures may lead to higher degradation in some, but not all, products. Wear-out non-linearities for the worst performing modules have been documented in a few select studies that took multiple measurements of an ensemble of modules during the lifetime of the system. However, the majority of these modules exhibit a fairly linear decline. Modeling these non-linearities, whether they occur at the beginning-of-life or end-of-life in the PV life cycle, has an important impact on the levelized cost of energy.« less

Model Development of Degradation of PV Modules Backsheet with Locating Place of Module

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

Kempe, Michael D; Wang, Yu; Fairbrother, Andrew

Performance of a photovoltaic (PV) module is related to the micro-environment around the module. The position of photovoltaic modules in an array row have a large effect on the yellowing and gloss of PV module backsheet exposed in Dfa climatic zone (Gaithersburg, MD) with a polyethylene naphthalate (PEN) outer layer. Stress/Response models of yellowing and gloss-losing as function of location parameters of module, including the shed, row, measurement position in a same module and the distance of module location to the row center, are under development. The module installation height had the greatest influence on degradation of PEN PV backsheetmore » in the Dfa climatic zone. The module backsheets at the end of an array have higher degradation rate (edge effect). The edge effect decreases with increasing of module installation heights.« less

Active optimal control strategies for increasing the efficiency of photovoltaic cells

NASA Astrophysics Data System (ADS)

Aljoaba, Sharif Zidan Ahmad

Energy consumption has increased drastically during the last century. Currently, the worldwide energy consumption is about 17.4 TW and is predicted to reach 25 TW by 2035. Solar energy has emerged as one of the potential renewable energy sources. Since its first physical recognition in 1887 by Adams and Day till nowadays, research in solar energy is continuously developing. This has lead to many achievements and milestones that introduced it as one of the most reliable and sustainable energy sources. Recently, the International Energy Agency declared that solar energy is predicted to be one of the major electricity production energy sources by 2035. Enhancing the efficiency and lifecycle of photovoltaic (PV) modules leads to significant cost reduction. Reducing the temperature of the PV module improves its efficiency and enhances its lifecycle. To better understand the PV module performance, it is important to study the interaction between the output power and the temperature. A model that is capable of predicting the PV module temperature and its effects on the output power considering the individual contribution of the solar spectrum wavelengths significantly advances the PV module edsigns toward higher efficiency. In this work, a thermoelectrical model is developed to predict the effects of the solar spectrum wavelengths on the PV module performance. The model is characterized and validated under real meteorological conditions where experimental temperature and output power of the PV module measurements are shown to agree with the predicted results. The model is used to validate the concept of active optical filtering. Since this model is wavelength-based, it is used to design an active optical filter for PV applications. Applying this filter to the PV module is expected to increase the output power of the module by filtering the spectrum wavelengths. The active filter performance is optimized, where different cutoff wavelengths are used to maximize the module output power. It is predicted that if the optimized active optical filter is applied to the PV module, the module efficiency is predicted to increase by about 1%. Different technologies are considered for physical implementation of the active optical filter.

On the relationship factor between the PV module temperature and the solar radiation on it for various BIPV configurations

NASA Astrophysics Data System (ADS)

Kaplanis, S.; Kaplani, E.

2014-10-01

Temperatures of c-Si, pc-Si and a-Si PV modules making part of a roof in a building or hanging outside windows with various inclinations were measured with respect to the Intensity of the solar radiation on them under various environmental conditions. A relationship coefficient f was provided whose values are compared to those from a PV array operating in a free standing mode on a terrace. A theoretical model to predict f was elaborated. According to the analysis, the coefficient f takes higher values for PV modules embedded on a roof compared to the free standing PV array. The wind effect is much stronger for the free standing PV than for any BIPV configuration, either the PV is part of the roof, or placed upon the roof, or is placed outside a window like a shadow hanger. The f coefficient depends on various parameters such as angle of inclination, wind speed and direction, as well as solar radiation. For very low wind speeds the effect of the angle of inclination, β, of the PV module with respect to the horizontal on PV temperature is clear. As the wind speed increases, the heat transfer from the PV module shifts from natural flow to forced flow and this effect vanishes. The coefficient f values range from almost 0.01 m2°C/W for free standing PV arrays at strong wind speeds, vW>7m/s, up to around 0.05 m2°C/W for the case of flexible PV modules which make part of the roof in a BIPV system.

Numerical method for angle-of-incidence correction factors for diffuse radiation incident photovoltaic modules

DOE PAGES

Marion, Bill

2017-03-27

Here, a numerical method is provided for solving the integral equation for the angle-of-incidence (AOI) correction factor for diffuse radiation incident photovoltaic (PV) modules. The types of diffuse radiation considered include sky, circumsolar, horizon, and ground-reflected. The method permits PV module AOI characteristics to be addressed when calculating AOI losses associated with diffuse radiation. Pseudo code is provided to aid users in the implementation, and results are shown for PV modules with tilt angles from 0° to 90°. Diffuse AOI losses are greatest for small PV module tilt angles. Including AOI losses associated with the diffuse irradiance will improve predictionsmore » of PV system performance.« less

The possibility of developing hybrid PV/T solar system

NASA Astrophysics Data System (ADS)

Dobrnjac, M.; Zivkovic, P.; Babic, V.

2017-05-01

An alternative and cost-effective solution to developing integrated PV system is to use hybrid photovoltaic/thermal (PV/T) solar system. The temperature of PV modules increases due to the absorbed solar radiation that is not converted into electricity, causing a decrease in their efficiency. In hybrid PV/T solar systems the reduction of PV module temperature can be combined with a useful fluid heating. In this paper we present the possibility of developing a new hybrid PV/T solar system. Hybrid PV/T system can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We developed PV/T prototype consisted of commercial PV module and thermal panel with our original solution of aluminium absorber with special geometric shapes. The main advantages of our combined PV/T system are: removing of heat from the PV panel; extending the lifetime of photovoltaic cells; excess of the removing heat from PV part is used to heat the fluid in the thermal part of the panel; the possibility of using on the roof and facade constructions because less weight.

Hybrid photovoltaic and thermoelectric module for high concentration solar system

NASA Astrophysics Data System (ADS)

Tamaki, Ryo; Toyoda, Takeshi; Tamura, Yoichi; Matoba, Akinari; Minamikawa, Toshiharu; Tokuda, Masayuki; Masui, Megumi; Okada, Yoshitaka

2017-09-01

A photovoltaic (PV) and thermoelectric (TE) hybrid module was developed for application to high concentration solar systems. The waste heat from the solar cells under concentrated light illumination was utilized to generate additional electricity by assembling TE devices below the multi-junction solar cells (MJSCs). Considering the high operating temperature of the PV and TE hybrid module compared with conventional concentrator PV modules, the TE device could compensate a part of the MJSC efficiency degradation at high temperature. The performance investigation clarified the feasibility of the hybrid PV and TE module under highly concentrated sunlight illumination.

NREL Adds Solar Array Field to Help Inform Consumers | NREL

Science.gov Websites

PV modules at NREL's new solar array field. Workers install PV modules just north of the NREL parking be Added Each Year Once completed, the new solar array field will house four rows of PV modules. The the lifetime of a PV system, and that increases the per-kilowatt-hour cost of generating solar

Research on Potential Induced Degradation (PID) of PV Modules in Different Typical Climate Regions

NASA Astrophysics Data System (ADS)

Daoren, Gong; Yingnan, Chen; Gang, Sun; Wenjing, Wang; Zhenshuang, Ji

2018-03-01

Potential Induced Degradation (PID) is one of the most important factors effecting the performances of Photovoltaic (PV) modules and PV systems in recent years. In this paper the PID phenomena of the PV power plant in different typical climate regions were studied and some experimental PID simulations were carried out in order to find out the factors effecting the performance by PID. The results show that the typical PID phenomena are easy to occur in cells close to the border of the PV module. PID phenomena can appear in PV power plants under different climate conditions, but the effecting degrees on module performance are different depending on temperature, humidity and other parameters. We also find the maximum power would recover in some degree after positive-bias voltage duration.

Stabilized PV system

DOEpatents

Dinwoodie, Thomas L.

2002-12-17

A stabilized PV system comprises an array of photovoltaic (PV) assemblies mounted to a support surface. Each PV assembly comprises a PV module and a support assembly securing the PV module to a position overlying the support surface. The array of modules is circumscribed by a continuous, belt-like perimeter assembly. Cross strapping, extending above, below or through the array, or some combination of above, below and through the array, secures a first position along the perimeter assembly to at least a second position along the perimeter assembly thereby stabilizing the array against wind uplift forces. The first and second positions may be on opposite sides on the array.

Analyzing the Energy Performance, Wind Loading, and Costs of Photovoltaic Slat Modules on Commercial Rooftops

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

Van Geet, Otto D.; Fu, Ran; Horowitz, Kelsey A.

NREL studied a new type of photovoltaic (PV) module configuration wherein multiple narrow, tilted slats are mounted in a single frame. Each slat of the PV slat module contains a single row of cells and is made using ordinary crystalline silicon PV module materials and processes, including a glass front sheet and weatherproof polymer encapsulation. Compared to a conventional ballasted system, a system using slat modules offer higher energy production and lower weight at lower LCOE. The key benefits of slat modules are reduced wind loading, improved capacity factor and reduced installation cost. First, the individual slats allow air tomore » flow through, which reduce wind loading. Using PV performance modeling software, we compared the performance of an optimized installation of slats modules to a typical installation of conventional modules in a ballasted rack mounting system. Based on the results of the performance modeling two different row tilt and spacing were tested in a wind tunnel. Scaled models of the PV Slat modules were wind tunnel tested to quantify the wind loading of a slat module system on a commercial rooftop, comparing the results to conventional ballasted rack mounted PV modules. Some commercial roofs do not have sufficient reserve dead load capacity to accommodate a ballasted system. A reduced ballast system design could make PV system installation on these roofs feasible for the first time without accepting the disadvantages of penetrating mounts. Finally, technoeconomic analysis was conducted to enable an economic comparison between a conventional commercial rooftop system and a reduced-ballast slat module installation.« less

Long term endurance test and contact degradation of CIGS solar cells

NASA Astrophysics Data System (ADS)

Ott, Thomas; Schönberger, Francillina; Walter, Thomas; Hariskos, Dimitrios; Kiowski, Oliver; Schäffler, Raymund

2013-09-01

CIGS is the most promising technology for thin-film solar cells with record efficiencies of 20.4 % on laboratory scale and 17.8 % aperture area efficiency on a 900 cm² module. Another important factor besides the cell efficiency is the reliability and long term stability of the manufactured modules, which can be assessed by accelerated ageing. In this contribution the accelerated ageing of CIGS mini modules has been investigated. Therefore, modules were dark annealed under dry heat conditions at different temperatures. During the endurance test a positive or negative bias was applied to the cells. In regular intervals the IV- and CV-characteristics were measured at room temperature. After an overall stress time of 3500 h the IV-characteristics were determined under different illumination conditions (intensity, spectral illumination). Our previous publications suggest a barrier at the back contact to explain the observed parameter drifts. This contribution is focused on the influence of different bias conditions during the endurance test on the generation of a back diode and on the change of the acceptor concentration. These parameter drifts have an impact on the open circuit voltage, fill factor and on the appearance of a cross over between dark and illuminated IV-characteristics. The interpretation of the observed parameter drifts was supported by SCAPS simulations based on the above mentioned back barrier model. As an outcome of the simulations signatures for the existence of a back barrier diode were established. IVmeasurements, temperature dependent Voc measurements and SunsVoc measurements are helpful means to detect such back diodes.

User's Manual for Data for Validating Models for PV Module Performance

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

Marion, W.; Anderberg, A.; Deline, C.

2014-04-01

This user's manual describes performance data measured for flat-plate photovoltaic (PV) modules installed in Cocoa, Florida, Eugene, Oregon, and Golden, Colorado. The data include PV module current-voltage curves and associated meteorological data for approximately one-year periods. These publicly available data are intended to facilitate the validation of existing models for predicting the performance of PV modules, and for the development of new and improved models. For comparing different modeling approaches, using these public data will provide transparency and more meaningful comparisons of the relative benefits.

Application of Distributed DC/DC Electronics in Photovoltaic Systems

NASA Astrophysics Data System (ADS)

Kabala, Michael

In a typical residential, commercial or utility grade photovoltaic (PV) system, PV modules are connected in series and in parallel to form an array that is connected to a standard DC/AC inverter, which is then connected directly to the grid. This type of standard installation; however, does very little to maximize the energy output of the solar array if certain conditions exist. These conditions could include age, temperature, irradiance and other factors that can cause mismatch between PV modules in an array that severely cripple the output power of the system. Since PV modules are typically connected in series to form a string, the output of the entire string is limited by the efficiency of the weakest module. With PV module efficiencies already relatively low, it is critical to extract the maximum power out of each module in order to make solar energy an economically viable competitor to oil and gas. Module level DC/DC electronics with maximum power point (MPP) tracking solves this issue by decoupling each module from the string in order for the module to operate independently of the geometry and complexity of the surrounding system. This allows each PV module to work at its maximum power point by transferring the maximum power the module is able to deliver directly to the load by either boosting (stepping up) the voltage or bucking (stepping down) the voltage. The goal of this thesis is to discuss the development of a per-module DC/DC converter in order to maximize the energy output of a PV module and reduce the overall cost of the system by increasing the energy harvest.

Bracket for photovoltaic modules

DOEpatents

Ciasulli, John; Jones, Jason

2014-06-24

Brackets for photovoltaic ("PV") modules are described. In one embodiment, a saddle bracket has a mounting surface to support one or more PV modules over a tube, a gusset coupled to the mounting surface, and a mounting feature coupled to the gusset to couple to the tube. The gusset can have a first leg and a second leg extending at an angle relative to the mounting surface. Saddle brackets can be coupled to a torque tube at predetermined locations. PV modules can be coupled to the saddle brackets. The mounting feature can be coupled to the first gusset and configured to stand the one or more PV modules off the tube.

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.

The Tucson Electric Power Solar Test Yard

NASA Astrophysics Data System (ADS)

Lonij, Vincent; Orsburn, Sean; Salhab, Anas; Kopp, Emily; Brooks, Adria; Jayadevan, Vijai; Greenberg, James; St. Germaine, Michael; Allen, Nate; Jones, Sarah; Hardesty, Garrett; Cronin, Alex

2011-10-01

In collaboration with Tucson Electric Power we studied the performance of twenty different grid-tied photovoltaic systems, consisting of over 600 PV modules in all. We added data acquisition hardware to monitor DC power from the modules, AC power from the inverters, PV module temperatures, and meteorological data such as the irradiance incident on the PV systems. We report measurements of PV system yields and efficiencies over periods of minutes, days, and years. We also report temperature and irradiance coefficients of efficiency and measurements of long-term degradation. We also use our data to validate models that predict the output from PV systems.

Dirk Jordan | NREL

Science.gov Websites

quantify module degradation rates. Statistical analysis of reported degradation rates of PV modules degradation rates," Prog. in PV 24(7), 2016, DOI: 10.1002/pip.2744 Jordan D.C., Silverman T.J PV, 2017, DOI: 10.1002/pip.2866 Jordan D.C., Silverman T.J., Sekulic B., Kurtz S.R., "PV

Photovoltaic performance and reliability workshop

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

Kroposki, B

1996-10-01

This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activitiesmore » to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results reported from field experience on modules, inverters, batteries, and charge controllers from field deployed PV systems; and system certification and standardized testing for stand-alone and grid-tied systems.« less

Design and simulation of maximum power point tracking (MPPT) system on solar module system using constant voltage (CV) method

NASA Astrophysics Data System (ADS)

Bhatara, Sevty Satria; Iskandar, Reza Fauzi; Kirom, M. Ramdlan

2016-02-01

Solar energy is one of renewable energy resource where needs a photovoltaic module to convert it into electrical energy. One of the problems on solar energy conversion is the process of battery charging. To improve efficiency of energy conversion, PV system needs another control method on battery charging called maximum power point tracking (MPPT). This paper report the study on charging optimation using constant voltage (CV) method. This method has a function of determining output voltage of the PV system on maximal condition, so PV system will always produce a maximal energy. A model represented a PV system with and without MPPT was developed using Simulink. PV system simulation showed a different outcome energy when different solar radiation and numbers of solar module were applied in the model. On the simulation of solar radiation 1000 W/m2, PV system with MPPT produces 252.66 Watt energy and PV system without MPPT produces 252.66 Watt energy. The larger the solar radiation, the greater the energy of PV modules was produced.

Photovoltaic array mounting apparatus, systems, and methods

DOEpatents

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

2014-12-02

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

Optimal design and operation of a photovoltaic-electrolyser system using particle swarm optimisation

NASA Astrophysics Data System (ADS)

Sayedin, Farid; Maroufmashat, Azadeh; Roshandel, Ramin; Khavas, Sourena Sattari

2016-07-01

In this study, hydrogen generation is maximised by optimising the size and the operating conditions of an electrolyser (EL) directly connected to a photovoltaic (PV) module at different irradiance. Due to the variations of maximum power points of the PV module during a year and the complexity of the system, a nonlinear approach is considered. A mathematical model has been developed to determine the performance of the PV/EL system. The optimisation methodology presented here is based on the particle swarm optimisation algorithm. By this method, for the given number of PV modules, the optimal sizeand operating condition of a PV/EL system areachieved. The approach can be applied for different sizes of PV systems, various ambient temperatures and different locations with various climaticconditions. The results show that for the given location and the PV system, the energy transfer efficiency of PV/EL system can reach up to 97.83%.

Surface and Bulk Effects of K in Highly Efficient Cu1-xKxInSe2 Solar Cells

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

Muzzillo, Christopher; Mansfield, Lorelle M; Ramanathan, Kannan

To advance knowledge of the beneficial effects of K in Cu(In,Ga)(Se,S)2 (CIGS) photovoltaic (PV) absorbers, recent Cu-K-In-Se phase growth studies have been extended to PV performance. First, the effect of distributing K throughout bulk Cu1-xKxInSe2 absorbers at low K/(K+Cu) compositions (0 = x = 0.30) was studied. Efficiency, open-circuit voltage (VOC), and fill factor (FF) were greatly enhanced for x ~ 0.07, resulting in an officially-measured 15.0%-efficient solar cell, matching the world record CuInSe2 efficiency. The improvements were a result of reduced interface and bulk recombination, relative to CuInSe2 (x ~ 0). However, higher x compositions had reduced efficiency, short-circuitmore » current density (JSC), and FF due to greatly increased interface recombination, relative to the x ~ 0 baseline. Next, the effect of confining K at the absorber/buffer interface at high K/(K+Cu) compositions (0.30 = x = 0.92) was researched. Previous work showed that these surface layer growth conditions produced CuInSe2 with a large phase fraction of KInSe2. After optimization (75 nm surface layer with x ~ 0.41), these KInSe2 surface samples exhibited increased efficiency (officially 14.9%), VOC, and FF as a result of decreased interface recombination. The KInSe2 surfaces had features similar to previous reports for KF post-deposition treatments (PDTs) used in world record CIGS solar cells - taken as indirect evidence that KInSe2 can form during these PDTs. Both the bulk and surface growth processes greatly reduced interface recombination. However, the KInSe2 surface had higher K levels near the surface, greater lifetimes, and increased inversion near the buffer interface, relative to the champion bulk Cu1-xKxInSe2 absorber. These characteristics demonstrate that K may benefit PV performance by different mechanisms at the surface and in the absorber bulk.« less

International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint

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

Wohlgemuth, J.; Kurtz, S.

The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests aremore » being developed for each of the selected climate zones.« less

PVMaT 1998 overview

NASA Astrophysics Data System (ADS)

Mittchell, Richard L.; Symko-Davies, Martha; Thomas, Holly P.; Witt, C. Edwin

1999-03-01

The Photovoltaic Manufacturing Technology (PVMaT) Project is a government/industry research and development (R&D) partnership between the U.S. federal government (through the U.S. Department of Energy [DOE]) and members of the U.S. PV industry. The goals of PVMaT are to assist the U.S. PV industry improve module manufacturing processes and equipment; accelerate manufacturing cost reductions for PV modules, balance-of-systems components, and integrated systems; increase commercial product performance and reliability; and enhance investment opportunities for substantial scale-ups of U.S.-based PV manufacturing plant capacities. The approach for PVMaT has been to cost-share the R&D risk as industry explores new manufacturing options and ideas for improved PV modules and components, advances system and product integration, and develops new system designs. These activities will lead to overall reduced system life-cycle costs for reliable PV end-products. The 1994 PVMaT Product-Driven BOS and Systems activities, as well as Product-Driven Module Manufacturing R&D activities, are just being completed. Fourteen new subcontracts have just been awarded in the areas of PV System and Component Technology and Module Manufacturing Technology. Government funding, subcontractor cost-sharing, and a comparison of the relative efforts by PV technology throughout the PVMaT project are also discussed.

Moving Toward Quantifying Reliability - The Next Step in a Rapidly Maturing PV Industry: Preprint

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

Kurtz, Sarah; Sample, Tony; Wohlgemuth, John

2015-12-07

Some may say that PV modules are moving toward being a simple commodity, but most major PV customers ask: 'How can I minimize chances of a module recall?' Or, 'How can I quantify the added value of a 'premium' module?' Or, 'How can I assess the value of an old PV system that I'm thinking of purchasing?' These are all questions that PVQAT (the International PV Quality Assurance Task Force) and partner organizations are working to answer. Defining standard methods for ensuring minimal acceptable quality of PV modules, differentiating modules that provide added value in the toughest of environments, andmore » creating a process (e.g. through IECRE [1]) that can follow a PV system from design through installation and operation are tough tasks, but having standard approaches for these will increase confidence, reduce costs, and be a critical foundation of a mature PV industry. This paper summarizes current needs for new tests, some challenges for defining those tests, and some of the key efforts toward development of international standards, emphasizing that meaningful quantification of reliability (as in defining a service life prediction) must be done in the context of a specific product with design parameters defined through a quality management system.« less

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

None

Module-level power electronics, such as DC power optimizers, microinverters, and those found in AC modules, are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software. This paper extends the work completed at NREL that provided recommendations to model the performance of distributed power electronics in NREL’s popular PVWatts calculator [1], to provide similar guidelines for modeling these technologies in NREL's more complex System Advisor Model (SAM). Module-level power electronics - such asmore » DC power optimizers, microinverters, and those found in AC modules-- are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software.« less

77 FR 73018 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-07

...., Ltd. (Chengdu) PV Module Co., Ltd. Canadian Solar International Canadian Solar 24.48 Limited..... Chint Solar (Zhejiang) 24.48 Co., Ltd. Suzhou Shenglong PV-Tech Co., Ltd Suzhou Shenglong PV-TECH 24.48.... Jetion Solar (China) Co., Ltd.... Jetion Solar (China) 24.48 Co., Ltd. Jiangsu Green Power PV Co., Ltd...

How Can We Make PV Modules Safer?: Preprint

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

Wohlgemuth, J. H.; Kurtz, S. R.

2012-06-01

Safety is a prime concern for the photovoltaics (PV) industry. As a technology deployed on residential and commercial buildings, it is critical that PV not cause damage to the buildings nor harm the occupants. Many of the PV systems on buildings are of sufficiently high voltage (300 to 600 Volts dc) that they may present potential hazards. These PV systems must be safe in terms of mechanical damage (nothing falls on someone), shock hazard (no risk of electrical shock when touching an exposed circuit element), and fire (the modules neither cause nor promote a fire). The present safety standards (IECmore » 61730 and UL 1703) do a good job of providing for design rules and test requirements for mechanical, shock, and spread of flame dangers. However, neither standard addresses the issue of electrical arcing within a module that can cause a fire. To make PV modules, they must be designed, built, and installed with an emphasis on minimizing the potential for open circuits and ground faults. This paper provides recommendations on redundant connection designs, robust mounting methods, and changes to the safety standards to yield safer PV modules.« less

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

DOEpatents

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

2013-12-31

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

Photovoltaic system with improved AC connections and method of making same

DOEpatents

Cioffi, Philip Michael; Todorovic, Maja Harfman; Herzog, Michael Scott; Korman, Charles Steven; Doherty, Donald M.; Johnson, Neil Anthony

2018-02-13

An alternating current (AC) harness for a photovoltaic (PV) system includes a wire assembly having a first end and a second end, the wire assembly having a plurality of lead wires, and at least one AC connection module positioned at a location along a length of the wire assembly between the first end and the second end. Further, the at least one AC connection module includes a first connection terminal electrically coupled to the plurality of lead wires of the wire assembly and constructed to electrically couple the wire assembly with an output of a first PV module of the PV system. The at least one AC connection module also includes a second connection terminal electrically coupled to the plurality of lead wires of the wire assembly and constructed to electrically couple the wire assembly with an output of a second PV module of the PV system.

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

DOEpatents

Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA; Culligan, Matthew [Berkeley, CA

2011-11-22

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

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

DOEpatents

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

2012-10-23

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

Durable crystalline Si photovoltaic modules based on silicone-sheet encapsulants

NASA Astrophysics Data System (ADS)

Hara, Kohjiro; Ohwada, Hiroto; Furihata, Tomoyoshi; Masuda, Atsushi

2018-02-01

Crystalline Si photovoltaic (PV) modules were fabricated with sheets of poly(dimethylsiloxane) (silicone) as an encapsulant. The long-term durability of the silicone-encapsulated PV modules was experimentally investigated. The silicone-based modules enhanced the long-term durability against potential-induced degradation (PID) and a damp-heat (DH) condition at 85 °C with 85% relative humidity (RH). In addition, we designed and fabricated substrate-type Si PV modules based on the silicone encapsulant and an Al-alloy plate as the substratum, which demonstrated high impact resistance and high incombustible performance. The high chemical stability, high volume resistivity, rubber-like elasticity, and incombustibility of the silicone encapsulant resulted in the high durability of the modules. Our results indicate that silicone is an attractive encapsulation material, as it improves the long-term durability of crystalline Si PV modules.

Photovoltaic module certification and laboratory accreditation criteria development

NASA Astrophysics Data System (ADS)

Osterwald, Carl R.; Zerlaut, Gene; Hammond, Robert; D'Aiello, Robert

1996-01-01

This paper overviews a model product certification and test laboratory accreditation program for photovoltaic (PV) modules that was recently developed by the National Renewable Energy Laboratory and Arizona State University. The specific objective of this project was to produce a document that details the equipment, facilities, quality assurance procedures, and technical expertise an accredited laboratory needs for performance and qualification testing of PV modules, along with the specific tests needed for a module design to be certified. The document was developed in conjunction with a criteria development committee consisting of representatives from 30 U.S. PV manufacturers, end users, standards and codes organizations, and testing laboratories. The intent is to lay the groundwork for a future U.S. PV certification and accreditation program that will be beneficial to the PV industry as a whole.

Cu(In,Ga)Se2 Solar Cells with Amorphous In2O3-Based Front Contact Layers.

PubMed

Koida, Takashi; Ueno, Yuko; Nishinaga, Jiro; Higuchi, Hirohumi; Takahashi, Hideki; Iioka, Masayuki; Shibata, Hajime; Niki, Shigeru

2017-09-06

Amorphous (a-) In 2 O 3 -based front contact layers composed of transparent conducting oxide (TCO) and transparent oxide semiconductor (TOS) layers were proved to be effective in enhancing the short-circuit current density (J sc ) of Cu(In,Ga)Se 2 (CIGS) solar cells with a glass/Mo/CIGS/CdS/TOS/TCO structure, while maintaining high fill factor (FF) and open-circuit voltage (V oc ). An n-type a-In-Ga-Zn-O layer was introduced between the CdS and TCO layers. Unlike unintentionally doped ZnO broadly used as TOS layers in CIGS solar cells, the grain-boundary(GB)-free amorphous structure of the a-In-Ga-Zn-O layers allowed high electron mobility with superior control over the carrier density (N). High FF and V oc values were achieved in solar cells containing a-In-Ga-Zn-O layers with N values broadly ranging from 2 × 10 15 to 3 × 10 18 cm -3 . The decrease in FF and V oc produced by the electronic inhomogeneity of solar cells was mitigated by controlling the series resistance within the TOS layer of CIGS solar cells. In addition, a-In 2 O 3 :H and a-In-Zn-O layers exhibited higher electron mobilities than the ZnO:Al layers conventionally used as TCO layers in CIGS solar cells. The In 2 O 3 -based layers exhibited lower free carrier absorption while maintaining similar sheet resistance than ZnO:Al. The TCO and TOS materials and their combinations did not significantly change the V oc of the CIGS solar cells and the mini-modules.

Supply Constraints Analysis | Energy Analysis | NREL

Science.gov Websites

module cost, and future price could be critical to the economic viability of this PV technology. Even constraints on future CdTe PV module deployment and found that: CdTe PV modules can remain cost-competitive and 4070 GW of annual CdTe production by 2030. Cost estimates were based on NREL's manufacturing cost

City and County Solar PV Training Program, Module 3: Detailed Site Evaluation, Project Validation, and Permitting

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

Day, Megan H; Lisell, Lars J

This is the third of five training modules recorded for the City and County Solar PV Training Program. The program is focused on training local government staff in the PV procurement process. This module focuses on siting and permitting for both rooftop and larger, ground-mounted systems rand includes a link to a video.

High throughput manufacturing of thin-film CdTe photovoltaic modules. Annual subcontract report, 16 November 1993--15 November 1994

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

Sandwisch, D W

1995-11-01

This report describes work performed by Solar Cells, Inc. (SCI), under a 3-year subcontract to advance SCI`s PV manufacturing technologies, reduce module production costs, increase module performance, and provide the groundwork for SCI to expand its commercial production capacities. SCI will meet these objectives in three phases by designing, debugging, and operating a 20-MW/year, automated, continuous PV manufacturing line that produces 60-cm {times} 120-cm thin-film CdTe PV modules. This report describes tasks completed under Phase 1 of the US Department of Energy`s PV Manufacturing Technology program.

The vital role of manufacturing quality in the reliability of PV modules

NASA Astrophysics Data System (ADS)

Rusch, Peter

2014-10-01

The influence of manufacturing quality on the reliability of PV modules coming out of today's factories has been, and is still, under estimated among investors and buyers. The main reason is perception. Contrary to popular belief, PV modules are not a commodity. Module quality does differ among module brands. Certification alone does not guarantee the quality or reliability of a module. Cost reductions in manufacturing have unequivocally affected module quality. And the use of new, cheaper materials has had a measureable impact on module reliability. The need for meaningful manufacturing quality standards has been understood by the leading technical institutions and important industry players. The fact that most leading PV panel manufacturers have been certified according to ISO 9001 has led to some level of improvement and higher effectiveness. The new ISO 9001 PV QMS standards will be a major step in providing a tool to assess PV manufacturers' quality management systems. The current lack of sufficient standards has still got a negative influence on the quality of modules being installed today. Today every manufacturer builds their modules in their own way with little standardization or adherence to quality processes and methods, which are commonplace in other manufacturing industries. Although photovoltaic technology is to a great extent mature, the way modules are being produced has changed significantly over the past few years and it continues to change at a rapid pace. Investors, financiers and lenders stand the most to gain from PV systems over the long-term, but also the most to lose. Investors, developers, EPC, O&M and solar asset management companies must all manage manufacturing quality more proactively or they will face unexpected risks and failures down the road. Manufacturing quality deserves more transparency and attention, as it is a major driver of module performance and reliability. This paper will explain the benefits of good manufacturing quality and the dangers in poor manufacturing quality. The paper also explains why buyers and long-term investors need to pay close attention to the day-to-day manufacturing quality of module manufacturers. We demonstrate how these quality risks can be assessed and mitigated by independent diligence, professional contracting and smart quality assurance processes that can be easily built into any module procurement process. We highlight the steps to ensure that every module used in a PV system is built to quality standards that support the long-term reliability of a PV system.

Comparison of efficiency degradation in polycrystalline-Si and CdTe thin-film PV modules via accelerated lifecycle testing

NASA Astrophysics Data System (ADS)

Lai, T.; Potter, B. G.; Simmons-Potter, K.

2017-08-01

Thin-film solar cells normally have the shortest energy payback time due to their simpler mass-production process compared to polycrystalline-Si photovoltaic (PV) modules, despite the fact that crystalline-Si-based technology typically has a longer total lifetime and a higher initial power conversion efficiency. For both types of modules, significant aging occurs during the first two years of usage with slower long-term aging over the module lifetime. The PV lifetime and the return-on-investment for local PV system installations rely on long-term device performance. Understanding the efficiency degradation behavior under a given set of environmental conditions is, therefore, a primary goal for experimental research and economic analysis. In the present work, in-situ measurements of key electrical characteristics (J, V, Pmax, etc.) in polycrystalline-Si and CdTe thin-film PV modules have been analyzed. The modules were subjected to identical environmental conditions, representative of southern Arizona, in a full-scale, industrial-standard, environmental degradation chamber, equipped with a single-sun irradiance source, temperature, and humidity controls, and operating an accelerated lifecycle test (ALT) sequence. Initial results highlight differences in module performance with environmental conditions, including temperature de-rating effects, for the two technologies. Notably, the thin-film CdTe PV module was shown to be approximately 15% less sensitive to ambient temperature variation. After exposure to a seven-month equivalent compressed night-day weather cycling regimen the efficiency degradation rates of both PV technology types were obtained and will be discussed.

Designing novel thin film polycrystalline solar cells for high efficiency: sandwich CIGS and heterojunction perovskite

NASA Astrophysics Data System (ADS)

Wang, Tianyue; Chen, Jiewei; Wu, Gaoxiang; Song, Dandan; Li, Meicheng

2017-01-01

Heterojunction and sandwich architectures are two new-type structures with great potential for solar cells. Specifically, the heterojunction structure possesses the advantages of efficient charge separation but suffers from band offset and large interface recombination; the sandwich configuration is favorable for transferring carriers but requires complex fabrication process. Here, we have designed two thin-film polycrystalline solar cells with novel structures: sandwich CIGS and heterojunction perovskite, referring to the advantages of the architectures of sandwich perovskite (standard) and heterojunction CIGS (standard) solar cells, respectively. A reliable simulation software wxAMPS is used to investigate their inherent characteristics with variation of the thickness and doping density of absorber layer. The results reveal that sandwich CIGS solar cell is able to exhibit an optimized efficiency of 20.7%, which is much higher than the standard heterojunction CIGS structure (18.48%). The heterojunction perovskite solar cell can be more efficient employing thick and doped perovskite films (16.9%) than these typically utilizing thin and weak-doping/intrinsic perovskite films (9.6%). This concept of structure modulation proves to be useful and can be applicable for other solar cells. Project supported by the National High-Tech R&D Program of China (No. 2015AA034601), the National Natural Science Foundation of China (Nos. 91333122, 61204064, 51202067, 51372082, 51402106, 11504107), the Ph.D. Programs Foundation of Ministry of Education of China (Nos. 20120036120006, 20130036110012), the Par-Eu Scholars Program, and the Fundamental Research Funds for the Central Universities.

Photovoltaic module and module arrays

DOEpatents

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

2013-08-27

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

Photovoltaic module and module arrays

DOEpatents

Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Lenox, Carl J. S. [Oakland, CA; Culligan, Matthew [Berkeley, CA; Danning, Matt [Oakland, CA

2012-07-17

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

Top Five Large-Scale Solar Myths | State, Local, and Tribal Governments |

Science.gov Websites

of large-scale photovoltaic (PV) facilities or solar farms tend to include a myriad of misperceptions technologies do use mirrors which can cause glare, most solar farms use PV modules to generate electricity. PV panels in order to convert solar energy into electricity. PV modules are generally less reflective than

NREL Photovoltaic Program FY 1995 annual report

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

NONE

1996-06-01

This report summarizes the in-house and subcontracted R&D activities from Oct. 1994 through Sept. 1995; their objectives are to conduct basic, applied, and engineering research, manage subcontracted R&D projects, perform research complementary to subcontracted work, develop and maintain state-of-the-art measurement and device capabilities, develop PV manufacturing technology and modules, transfer results to industry, and evolve viable partnerships for PV systems and market development. The research activities are grouped into 5 sections: crystalline Si and advanced devices, thin-film PV, PV manufacturing, PV module and system performance and engineering, and PV applications and market development.

Modeling the irradiance and temperature rependence of photovoltaic modules in PVsyst

DOE PAGES

Sauer, Kenneth J.; Roessler, Thomas; Hansen, Clifford W.

2014-11-10

In order to reliably simulate the energy yield of photovoltaic (PV) systems, it is necessary to have an accurate model of how the PV modules perform with respect to irradiance and cell temperature. Building on previous work that addresses the irradiance dependence, two approaches to fit the temperature dependence of module power in PVsyst have been developed and are applied here to recent multi-irradiance and -temperature data for a standard Yingli Solar PV module type. The results demonstrate that it is possible to match the measured irradiance and temperature dependence of PV modules in PVsyst. As a result, improvements inmore » energy yield prediction using the optimized models relative to the PVsyst standard model are considered significant for decisions about project financing.« less

Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

DOE PAGES

Xiao, Bailu; Hang, Lijun; Mei, Jun; ...

2014-09-04

This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is alsomore » proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.« less

Parameters Identification for Photovoltaic Module Based on an Improved Artificial Fish Swarm Algorithm

PubMed Central

Wang, Hong-Hua

2014-01-01

A precise mathematical model plays a pivotal role in the simulation, evaluation, and optimization of photovoltaic (PV) power systems. Different from the traditional linear model, the model of PV module has the features of nonlinearity and multiparameters. Since conventional methods are incapable of identifying the parameters of PV module, an excellent optimization algorithm is required. Artificial fish swarm algorithm (AFSA), originally inspired by the simulation of collective behavior of real fish swarms, is proposed to fast and accurately extract the parameters of PV module. In addition to the regular operation, a mutation operator (MO) is designed to enhance the searching performance of the algorithm. The feasibility of the proposed method is demonstrated by various parameters of PV module under different environmental conditions, and the testing results are compared with other studied methods in terms of final solutions and computational time. The simulation results show that the proposed method is capable of obtaining higher parameters identification precision. PMID:25243233

On the Path to SunShot - The Role of Advancements in Solar Photovoltaic Efficiency, Reliability, and Costs

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

Woodhouse, Michael; Jones-Albertus, Rebecca; Feldman, David

2016-05-01

Although tremendous progress has been made in reducing the cost of PV systems, additional LCOE reductions of 40%–50% between 2015 and 2020 will be required to reach the SunShot Initiative’s targets (see Woodhouse et al. 2016). Understanding the tradeoffs between installed prices and other PV system characteristics—such as module efficiency, module degradation rate, and system lifetime—are vital. For example, with 29%-efficient modules and high reliability (a 50-year lifetime and a 0.2%/year module degradation rate), a residential PV system could achieve the SunShot LCOE goal with modules priced at almost $1.20/W. But change the lifetime to 10 years and the degradationmore » rate to 2%/year, and the system would need those very high-efficiency modules at zero cost to achieve the same LCOE. Although these examples are extreme, they serve to illustrate the wide range of technological combinations that could help drive PV toward the LCOE goals. SunShot’s PV roadmaps illustrate specific potential pathways to the target cost reductions.« less

Specific energy yield comparison between crystalline silicon and amorphous silicon based PV modules

NASA Astrophysics Data System (ADS)

Ferenczi, Toby; Stern, Omar; Hartung, Marianne; Mueggenburg, Eike; Lynass, Mark; Bernal, Eva; Mayer, Oliver; Zettl, Marcus

2009-08-01

As emerging thin-film PV technologies continue to penetrate the market and the number of utility scale installations substantially increase, detailed understanding of the performance of the various PV technologies becomes more important. An accurate database for each technology is essential for precise project planning, energy yield prediction and project financing. However recent publications showed that it is very difficult to get accurate and reliable performance data of theses technologies. This paper evaluates previously reported claims the amorphous silicon based PV modules have a higher annual energy yield compared to crystalline silicon modules relative to their rated performance. In order to acquire a detailed understanding of this effect, outdoor module tests were performed at GE Global Research Center in Munich. In this study we examine closely two of the five reported factors that contribute to enhanced energy yield of amorphous silicon modules. We find evidence to support each of these factors and evaluate their relative significance. We discuss aspects for improvement in how PV modules are sold and identify areas for further study further study.

Effects of different excitation waveforms on detection and characterisation of delamination in PV modules by active infrared thermography

NASA Astrophysics Data System (ADS)

Sinha, Archana; Gupta, Rajesh

2017-10-01

Delamination significantly affects the performance and reliability of photovoltaic (PV) modules. Recently, an active infrared thermography approach using step heating has been exploited for the detection and characterisation of delamination in PV modules. However, step heating takes longer observation time and causes overheating problems. This paper presents the effects of different thermal excitation waveforms namely rectangular, half-sine and short pulse, on the detection and characterisation of delamination in PV module by experiments and simulations. For simulation, a 3-dimensional electro-thermal model of heat conduction, based on resistance-capacitance network approach, has been exploited to study the variation in maximum thermal contrast and peak contrast time with the delamination thickness and heating parameters. Results show that the rectangular waveform provides better detection of delamination due to higher absolute contrast, while the half-sine waveform allows better characterisation of delamination in the PV modules with low-cost and low-power heat source. The high-energy short pulse enabled quick visualisation of delamination, but has limited practical implementation. The advantages and limitations of each waveform have been highlighted to assess the specific requirement for appropriate choice in the non-destructive thermographic inspection of delamination in PV modules at the manufacturing units or outdoor fields.

Evolution of integrated panel structural design and interfaces for PV power plants

NASA Technical Reports Server (NTRS)

Arnett, J. C.; Anderson, A. J.; Robertson, R. E.

1983-01-01

The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.

Quantifying Reliability - The Next Step for a Rapidly Maturing PV Industry and China's Role

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

Kurtz, Sarah

2015-10-14

PV customers wish to know how long their PV modules will last, but quantitatively predicting service life is difficult because of the large number of ways that a module can fail, the variability of the use environment, the cost of the testing, and the short product development time, especially when compared with the long desired lifetime. China should play a key role in developing international standards because China manufactures most of the world's PV modules. The presentation will describe the steps that need to be taken to create a service life prediction within the context of a defined bill ofmore » materials, process window and use environment. Worldwide standards for cost-effective approaches to service-life predictions will be beneficial to both PV customers and manufacturers since the consequences of premature module failure can be disastrous for both.« less

SMART empirical approaches for predicting field performance of PV modules from results of reliability tests

NASA Astrophysics Data System (ADS)

Hardikar, Kedar Y.; Liu, Bill J. J.; Bheemreddy, Venkata

2016-09-01

Gaining an understanding of degradation mechanisms and their characterization are critical in developing relevant accelerated tests to ensure PV module performance warranty over a typical lifetime of 25 years. As newer technologies are adapted for PV, including new PV cell technologies, new packaging materials, and newer product designs, the availability of field data over extended periods of time for product performance assessment cannot be expected within the typical timeframe for business decisions. In this work, to enable product design decisions and product performance assessment for PV modules utilizing newer technologies, Simulation and Mechanism based Accelerated Reliability Testing (SMART) methodology and empirical approaches to predict field performance from accelerated test results are presented. The method is demonstrated for field life assessment of flexible PV modules based on degradation mechanisms observed in two accelerated tests, namely, Damp Heat and Thermal Cycling. The method is based on design of accelerated testing scheme with the intent to develop relevant acceleration factor models. The acceleration factor model is validated by extensive reliability testing under different conditions going beyond the established certification standards. Once the acceleration factor model is validated for the test matrix a modeling scheme is developed to predict field performance from results of accelerated testing for particular failure modes of interest. Further refinement of the model can continue as more field data becomes available. While the demonstration of the method in this work is for thin film flexible PV modules, the framework and methodology can be adapted to other PV products.

Spectrum sensitivity, energy yield, and revenue prediction of PV and CPV modules

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

Kinsey, Geoffrey S., E-mail: Geoffrey.kinsey@ee.doe.gov

2015-09-28

Impact on module performance of spectral irradiance variation has been determined for III-V multijunctions compared against the four most common flat-plate module types (cadmium telluride, multicrystalline silicon, copper indium gallium selenide, and monocrystalline silicon. Hour-by-hour representative spectra were generated using atmospheric variables for Albuquerque, New Mexico, USA. Convolution with published values for external quantum efficiency gave the predicted current output. When combined with specifications of commercial PV modules, energy yield and revenue were predicted. This approach provides a means for optimizing PV module design based on various site-specific temporal variables.

Spectrum sensitivity, energy yield, and revenue prediction of PV and CPV modules

NASA Astrophysics Data System (ADS)

Kinsey, Geoffrey S.

2015-09-01

Impact on module performance of spectral irradiance variation has been determined for III-V multijunctions compared against the four most common flat-plate module types (cadmium telluride, multicrystalline silicon, copper indium gallium selenide, and monocrystalline silicon. Hour-by-hour representative spectra were generated using atmospheric variables for Albuquerque, New Mexico, USA. Convolution with published values for external quantum efficiency gave the predicted current output. When combined with specifications of commercial PV modules, energy yield and revenue were predicted. This approach provides a means for optimizing PV module design based on various site-specific temporal variables.

Low-Cd CIGS solar cells made with a hybrid CdS/Zn(O,S) buffer layer

DOE PAGES

Garris, Rebekah L.; Mansfield, Lorelle M.; Egaas, Brian; ...

2016-10-27

In Cu(In,Ga)Se2 (CIGS) solar cells, CdS and Zn(O,S) buffer layers were compared with a hybrid buffer layer consisting of thin CdS followed Zn(O,S). We explore the physics of this hybrid layer that combines the standard (Cd) approach with the alternative (Zn) approach in the pursuit to unlock further potential for CIGS technology. CdS buffer development has shown optimal interface properties, whereas Zn(O,S) buffer development has shown increased photocurrent. Although a totally Cd-free solar module is more marketable, the retention of a small amount of Cd can be beneficial to achieve optimum junction properties. As long as the amount of Cdmore » is reduced to less than 0.01% by weight, the presence of Cd does not violate the hazardous substance restrictions of the European Union (EU). We estimate the amount of Cd allowed in the EU for CIGS on both glass and stainless steel substrates, and we show that reducing Cd becomes increasingly important as substrate weights decrease. As a result, this hybrid buffer layer had reduced Cd content and a wider space charge region, while achieving equal or better solar cell performance than buffer layers of either CdS or Zn(O,S) alone.« less

Seventh workshop on the role of impurities and defects in silicon device processing

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

NONE

1997-08-01

This workshop is the latest in a series which has looked at technological issues related to the commercial development and success of silicon based photovoltaic (PV) modules. PV modules based on silicon are the most common at present, but face pressure from other technologies in terms of cell performance and cell cost. This workshop addresses a problem which is a factor in the production costs of silicon based PV modules.

Economically Sustainable Scaling of Photovoltaics to Meet Climate Targets

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

Needleman, David Berney; Poindexter, Jeremy R.; Kurchin, Rachel C.

To meet climate goals, photovoltaics (PV) deployment will have to grow rapidly over the next fifteen years. We identify two barriers to this growth: scale-up of manufacturing capacity and the cost of PV module production. We explore several technoeconomic approaches to overcoming these barriers and identify deep reductions in the capital intensity (capex) of PV module manufacturing and large increases in module efficiency as the most promising routes to rapid deployment. Given the lag inherent in rolling out new technology, we explore an approach where growth is fueled by debt or subsidies in the short-term and technological advances in themore » medium term. Finally, we analyze the current capex structure of crystalline silicon PV module manufacturing to identify potential savings.« less

76 FR 9766 - Nationwide Limited Public Interest Waiver Under Section 1605 (Buy American) of the American...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-22

... interest waiver), with respect to the following solar photo-voltaic (PV) equipment: (1) Domestically... utilized in a solar installation involving a U.S. manufactured PV module, or a module manufactured abroad... incidental and/or ancillary solar Photovoltaic (PV) equipment, when this equipment is utilized in solar...

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 13.5% efficiency. Further improvements could be made through the incorporation of a front-surface field, surface texturing and nitride ARC.

Short-term PV/T module temperature prediction based on PCA-RBF neural network

NASA Astrophysics Data System (ADS)

Li, Jiyong; Zhao, Zhendong; Li, Yisheng; Xiao, Jing; Tang, Yunfeng

2018-02-01

Aiming at the non-linearity and large inertia of temperature control in PV/T system, short-term temperature prediction of PV/T module is proposed, to make the PV/T system controller run forward according to the short-term forecasting situation to optimize control effect. Based on the analysis of the correlation between PV/T module temperature and meteorological factors, and the temperature of adjacent time series, the principal component analysis (PCA) method is used to pre-process the original input sample data. Combined with the RBF neural network theory, the simulation results show that the PCA method makes the prediction accuracy of the network model higher and the generalization performance stronger than that of the RBF neural network without the main component extraction.

Multiobjective Particle Swarm Optimization for the optimal design of photovoltaic grid-connected systems

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

Kornelakis, Aris

2010-12-15

Particle Swarm Optimization (PSO) is a highly efficient evolutionary optimization algorithm. In this paper a multiobjective optimization algorithm based on PSO applied to the optimal design of photovoltaic grid-connected systems (PVGCSs) is presented. The proposed methodology intends to suggest the optimal number of system devices and the optimal PV module installation details, such that the economic and environmental benefits achieved during the system's operational lifetime period are both maximized. The objective function describing the economic benefit of the proposed optimization process is the lifetime system's total net profit which is calculated according to the method of the Net Present Valuemore » (NPV). The second objective function, which corresponds to the environmental benefit, equals to the pollutant gas emissions avoided due to the use of the PVGCS. The optimization's decision variables are the optimal number of the PV modules, the PV modules optimal tilt angle, the optimal placement of the PV modules within the available installation area and the optimal distribution of the PV modules among the DC/AC converters. (author)« less

Processing of CuInSe{sub 2}-based solar cells: Characterization of deposition processes in terms of chemical reaction analyses. Phase 2 Annual Report, 6 May 1996--5 May 1997

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

Anderson, T.

This report describes research performed by the University of Florida during Phase 2 of this subcontract. First, to study CIGS, researchers adapted a contactless, nondestructive technique previously developed for measuring photogenerated excess carrier lifetimes in SOI wafers. This dual-beam optical modulation (DBOM) technique was used to investigate the differences between three alternative methods of depositing CdS (conventional chemical-bath deposition [CBD], metal-organic chemical vapor deposition [MOCVD], and sputtering). Second, a critical assessment of the Cu-In-Se thermochemical and phase diagram data using standard CALPHAD procedures is being performed. The outcome of this research will produce useful information on equilibrium vapor compositions (requiredmore » annealing ambients, Sex fluxes from effusion cells), phase diagrams (conditions for melt-assisted growth), chemical potentials (driving forces for diffusion and chemical reactions), and consistent solution models (extents of solid solutions and extending phase diagrams). Third, an integrated facility to fabricate CIS PV devices was established that includes migration-enhanced epitaxy (MEE) for deposition of CIS, a rapid thermal processing furnace for absorber film formation, sputtering of ZnO, CBD or MOCVD of CdS, metallization, and pattern definition.« less

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

NASA Technical Reports Server (NTRS)

Christensen, Elmer

1985-01-01

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

PV industry growth and module reliability in Thailand

NASA Astrophysics Data System (ADS)

Chenvidhya, Dhirayut; Seapan, Manit; Sangpongsanont, Yaowanee; Chenvidhya, Tanokkorn; Limsakul, Chamnan; Songprakorp, Roongrojana

2015-09-01

The PV applications in Thailand are now installed more than 1.2 GWp cumulatively. It is due to the National Renewable Energy Program and its targets. In the latest Alternative Energy Development Plan (AEDP), the PV electricity production target has increased from 2 GWp to 3 GWp. With this rapid growth, customers and manufacturers seek for module standard testing. So far over one thousands of PV modules per annum have been tested since 2012. The normal tests include type approval test according to TIS standard, acceptance test and testing for local standard development. For type test, the most module failure was found during damp heat test. For annual evaluation test, the power degradation and delamination of power was found between 0 to 6 percent from its nameplate after deployment of 0 to 5 years in the field. For thin-film module, the degradation and delamination was found in range of 0 to 13 percent (about 5 percent on average) from its nameplate for the modules in operation with less than 5 years. However, for the PV modules at the reference site on campus operated for 12 years, the power degradation was ranging from 10 to 15 percent. Therefore, a long term performance assessment needs to be considered to ensure the system reliability.

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

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.

City and County Solar PV Training Program, Module 2: Screening and Identifying PV Projects

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

Elgqvist, Emma M

When screening and identifying PV projects, cities and counties should understand the different factors that impact the technical and economic potential of a PV project, the steps of the PV screening process, and how to use REopt Lite to screen a site for PV and storage project potential.

Photovoltaic system derived data for determining the solar resource and for modeling the performance of other photovoltaic systems

DOE PAGES

Marion, Bill; Smith, Benjamin

2017-03-27

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. Here, a method was developed to back-solve for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the measured ac power of south-facing PV module/micro-inverter systems. The method was validated using one year of irradiance and PV performance measurements for five PV systems, each with a different tilt/azimuth orientation, and located in Golden, Colorado. Compared to using a measured global horizontal irradiance for PV performance model input,more » using the back-solved values of DNI and DHI only increased the range of mean bias deviations from measured values by 0.6% for the modeled annual averages of the global tilt irradiance and ac power for the five PV systems. Correcting for angle-of-incidence effects is an important feature of the method to prevent underestimating the solar resource and for modeling the performance of PV systems with more dissimilar PV module orientations. The results for the method were also shown more favorable than the results when using an existing power projection method for estimating the ac power.« less

Photovoltaic system derived data for determining the solar resource and for modeling the performance of other photovoltaic systems

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

Marion, Bill; Smith, Benjamin

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. Here, a method was developed to back-solve for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the measured ac power of south-facing PV module/micro-inverter systems. The method was validated using one year of irradiance and PV performance measurements for five PV systems, each with a different tilt/azimuth orientation, and located in Golden, Colorado. Compared to using a measured global horizontal irradiance for PV performance model input,more » using the back-solved values of DNI and DHI only increased the range of mean bias deviations from measured values by 0.6% for the modeled annual averages of the global tilt irradiance and ac power for the five PV systems. Correcting for angle-of-incidence effects is an important feature of the method to prevent underestimating the solar resource and for modeling the performance of PV systems with more dissimilar PV module orientations. The results for the method were also shown more favorable than the results when using an existing power projection method for estimating the ac power.« less

Space Station Freedom solar array panels plasma interaction test facility

NASA Technical Reports Server (NTRS)

Martin, Donald F.; Mellott, Kenneth D.

1989-01-01

The Space Station Freedom Power System will make extensive use of photovoltaic (PV) power generation. The phase 1 power system consists of two PV power modules each capable of delivering 37.5 KW of conditioned power to the user. Each PV module consists of two solar arrays. Each solar array is made up of two solar blankets. Each solar blanket contains 82 PV panels. The PV power modules provide a 160 V nominal operating voltage. Previous research has shown that there are electrical interactions between a plasma environment and a photovoltaic power source. The interactions take two forms: parasitic current loss (occurs when the currect produced by the PV panel leaves at a high potential point and travels through the plasma to a lower potential point, effectively shorting that portion of the PV panel); and arcing (occurs when the PV panel electrically discharges into the plasma). The PV solar array panel plasma interaction test was conceived to evaluate the effects of these interactions on the Space Station Freedom type PV panels as well as to conduct further research. The test article consists of two active solar array panels in series. Each panel consists of two hundred 8 cm x 8 cm silicon solar cells. The test requirements dictated specifications in the following areas: plasma environment/plasma sheath; outgassing; thermal requirements; solar simulation; and data collection requirements.

LCP- LIFETIME COST AND PERFORMANCE MODEL FOR DISTRIBUTED PHOTOVOLTAIC SYSTEMS

NASA Technical Reports Server (NTRS)

Borden, C. S.

1994-01-01

The Lifetime Cost and Performance (LCP) Model was developed to assist in the assessment of Photovoltaic (PV) system design options. LCP is a simulation of the performance, cost, and revenue streams associated with distributed PV power systems. LCP provides the user with substantial flexibility in specifying the technical and economic environment of the PV application. User-specified input parameters are available to describe PV system characteristics, site climatic conditions, utility purchase and sellback rate structures, discount and escalation rates, construction timing, and lifetime of the system. Such details as PV array orientation and tilt angle, PV module and balance-of-system performance attributes, and the mode of utility interconnection are user-specified. LCP assumes that the distributed PV system is utility grid interactive without dedicated electrical storage. In combination with a suitable economic model, LCP can provide an estimate of the expected net present worth of a PV system to the owner, as compared to electricity purchased from a utility grid. Similarly, LCP might be used to perform sensitivity analyses to identify those PV system parameters having significant impact on net worth. The user describes the PV system configuration to LCP via the basic electrical components. The module is the smallest entity in the PV system which is modeled. A PV module is defined in the simulation by its short circuit current, which varies over the system lifetime due to degradation and failure. Modules are wired in series to form a branch circuit. Bypass diodes are allowed between modules in the branch circuits. Branch circuits are then connected in parallel to form a bus. A collection of buses is connected in parallel to form an increment to capacity of the system. By choosing the appropriate series-parallel wiring design, the user can specify the current, voltage, and reliability characteristics of the system. LCP simulation of system performance is site-specific and follows a three-step procedure. First the hourly power produced by the PV system is computed using a selected year's insolation and temperature profile. For this step it is assumed that there are no module failures or degradation. Next, the monthly simulation is performed involving a month to month progression through the lifetime of the system. In this step, the effects of degradation, failure, dirt accumulation and operations/maintenance efforts on PV system performance over time are used to compute the monthly power capability fraction. The resulting monthly power capability fractions are applied to the hourly power matrix from the first step, giving the anticipated hourly energy output over the lifetime of the system. PV system energy output is compared with the PV system owner's electricity demand for each hour. The amount of energy to be purchased from or sold to the utility grid is then determined. Monthly expenditures on the PV system and the purchase of electricity from the utility grid are also calculated. LCP generates output reports pertaining to the performance of the PV system, and system costs and revenues. The LCP model, written in SIMSCRIPT 2.5 for batch execution on an IBM 370 series computer, was developed in 1981.

The Theory of Planned Behavior and E-cig Use: Impulsive Personality, E-cig Attitudes, and E-cig Use.

PubMed

Hershberger, Alexandra; Connors, Miranda; Um, Miji; Cyders, Melissa A

2018-04-01

The current paper applied the Theory of Planned Behavior (TPB; Ajzen & Fishbein, 1988) to understand how impulsive personality traits and attitudes concerning e-cig use relate to the likelihood of electronic cigarette (e-cig) use. Seven hundred and fourteen participants (Mean age = 34.04, SD = 10.89, 48.6% female) completed cross-sectional measures of e-cig use attitudes (CEAC) and the Short UPPS-P Impulsive Behavior Scale. A structural path analysis suggested that urgency and deficits in conscientiousness were significantly related to e-cig attitudes (CFI = 0.99, TLI = 0.99, RMSEA = 0.02; urgency: β = 0.32, p = .001; deficits in conscientiousness: β = -0.48, p < .001). E-cig attitude scores were significantly higher for e-cig users than non-users, β = 0.85, p < .001. There was no significant direct path from impulsive personality traits to e-cig use. Findings provide initial support for a model in which impulsive traits are related to e-cig use through positive e-cig attitudes.

A novel anti-theft security system for photovoltaic modules

NASA Astrophysics Data System (ADS)

Khan, Wasif Ali; Lim, Boon-Han; Lai, An-Chow; Chong, Kok-Keong

2017-04-01

Solar farms are considered as easy target for thieves because of insufficient protection measures. Existing anti-theft approaches are based on system level and are not very preventive and efficient because these can be bypassed with some technical knowledge. Additionally, it is difficult for security guards to tackle them as robbers come in a form of a gang equipped with heavy weapons. In this paper, a low power auto shut-off and non-destructive system is proposed for photovoltaic (PV) modules to achieve better level of security at module level. In proposed method, the power generation function of the PV module will be shut-off internally and cannot be re-activated by unauthorized personnel, in the case of theft. Hence, the PV module will not be functional even sold to new customers. The system comprises of a microcontroller, a low power position sensor, a controllable semiconductor switch and a wireless reactive-able system. The anti-theft system is developed to be laminated inside PV module and will be interconnected with solar cells so it becomes difficult for thieves to temper. The position of PV module is retrieved by position sensor and stored in a microcontroller as an initial reference value. Microcontroller uses this stored reference value to control power supply of PV module via power switch. The stored reference value can be altered using wireless circuitry by following authentication protocol. It makes the system non-destructive as anti-theft function can be reset again by authorized personnel, if it is recovered after theft or moved for maintenance purposes. The research component includes the design of a position sensing circuit, an auto shut-off circuit, a reactive-able wireless security protection algorithm and finally the integration of the multiple circuits.

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

DOE PAGES

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.; ...

2017-11-10

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Measurement of Relaxation Time of Excess Carriers in Si and CIGS Solar Cells by Modulated Electroluminescence Technique

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

Khatavkar, Sanchit; Muniappan, Kulasekaran; Kannan, Chinna V.

Excess carrier lifetime plays a crucial role in determining the efficiency of solar cells. In this paper, we use the frequency dependence of inphase and quadrature components of modulated electroluminescence (MEL) to measure the relaxation time (decay) of excess carriers. The advantage of the MEL technique is that the relaxation time is obtained directly from the angular frequency at which the quadrature component peaks. It does not need knowledge of the material parameters like mobility, etc., and can be used for any finished solar cells which have detectable light emission. The experiment is easy to perform with standard electrical equipment.more » For silicon solar cells, the relaxation time is dominated by recombination and hence, the relaxation time is indeed the excess carrier lifetime. In contrast, for the CIGS solar cells investigated here, the relaxation time is dominated by trapping and emission from shallow minority carrier traps.« less

Terrestrial photovoltaic collector technology trends

NASA Technical Reports Server (NTRS)

Shimada, K.; Costogue, E.

1984-01-01

Following the path of space PV collector development in its early stages, terrestrial PV technologies based upon single-crystal silicon have matured rapidly. Currently, terrestrial PV cells with efficiencies approaching space cell efficiencies are being fabricated into modules at a fraction of the space PV module cost. New materials, including CuInSe2 and amorphous silicon, are being developed for lowering the cost, and multijunction materials for achieving higher efficiency. Large grid-interactive, tracking flat-plate power systems and concentrator PV systems totaling about 10 MW, are already in operation. Collector technology development both flat-plate and concentrator, will continue under an extensive government and private industry partnership.

Characterization of efficiency-limiting resistance losses in monolithically integrated Cu(In,Ga)Se2 solar modules

PubMed Central

Yoon, Ju-Heon; Park, Jong-Keuk; Kim, Won Mok; Lee, JinWoo; Pak, Hisun; Jeong, Jeung-hyun

2015-01-01

The cell-to-module efficiency gap in Cu(In,Ga)Se2 (CIGS) monolithically integrated solar modules is enhanced by contact resistance between the Al-doped ZnO (AZO) and Mo back contact layers, the P2 contact, which connects adjacent cells. The present work evaluated the P2 contact resistance, in addition to the TCO resistance, using an embedded transmission line structure in a commercial-grade module without using special sample fabrication methods. The AZO layers between cells were not scribed; instead, the CIGS/CdS/i-ZnO/AZO device was patterned in a long stripe to permit measurement of the Mo electrode pair resistance over current paths through two P2 contacts (Mo/AZO) and along the AZO layer. The intercept and slope of the resistance as a function of the electrode interval yielded the P2 contact resistance and the TCO resistance, respectively. Calibration of the parasitic resistances is discussed as a method of improving the measurement accuracy. The contribution of the P2 contact resistance to the series resistance was comparable to that of the TCO resistance, and its origin was attributed to remnant MoSe2 phases in the P2 region, as verified by transmission electron microscopy. PMID:25573530

Performances and failure of field-aged PV modules operating in Saharan region of Algeria

NASA Astrophysics Data System (ADS)

Sadok, M.; Benyoucef, B.; Othmani, M.; Mehdaoui, A.

2016-07-01

This article deals with behaviour of PV modules, of different technologies and manufacturers, exposed for long periods in Saharan region of Algeria. These modules are exposed in Adrar in the south-western part of Algeria. The study uses experimental I-V curves of PV modules for determining their performances. The datasheet information of modules will be useful in determination of degradation rates of the modules. Three types of modules have been tested: Photowatt (PWX 500), UDTS-50 and Isofoton (I-75 and I-100 serials). Results showed that Isofoton I-100 modules present the highest degradation rate while the lowest degradation rate was reached with I-75 serial. However, these rates tallies with other studies. The visual inspection of the modules has revealed various kinds of failures and defects responsible of performances drop (EVA browning, delamination, burn marks,…).

Fundamental Studies of Adhesion of Dust to PV Module Surfaces: Chemical and Physical Relationships at the Microscale

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

Kazmerski, Lawrence L.; Diniz, Antonia Sonia A. C.; Maia, Cristiana Brasil

Photovoltaic (PV) module soiling is a growing area of concern for performance and reliability. This paper provides evaluations of the fundamental interactions of dust/soiling particles with several PV module surfaces. The purpose is to investigate the basic mechanisms involving the chemistry, morphology, and resulting particle adhesion to the first photon-incident surface. The evaluation and mapping of the chemistry and composition of single dust particles collected from operating PV module surfaces are presented. The first correlated direct measurements of the adhesive force of individual grains from field-operating collectors on identical PV module glass are reported, including correlations with specific compositions. Specialmore » microscale atomic force microscopy techniques are adapted to determine the force between the particle and the module glass surface. Results are presented for samples under dry and moisture-exposed conditions, confirming the effects of cementation for surfaces having soluble mineral and/or organic concentrations. Additionally, the effects of hydrocarbon fuels on the enhanced bonding of soiling particles to surfaces are determined for samples from urban and highly trafficked regions. Comparisons between glass and dust-mitigating superhydrophobic and superhydrophilic coatings are presented. Potential limitations of this proximal probe technique are discussed in terms of results and initial proof-of-concept experiments.« less

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

Module 1: Text Versions | State, Local, and Tribal Governments | NREL

Science.gov Websites

bonus module is on using solar PV for resilience. And, as Jenny and Harrison both mentioned, if you do working definition. To simply resilience and to incorporate solutions like on-site solar PV, NREL has into solar PV projects. Energy resilience can only be achieved by understanding energy needs and

The Use of Feature Parameters to Asses Barrier Properties of ALD coatings for Flexible PV Substrates

NASA Astrophysics Data System (ADS)

Blunt, Liam; Robbins, David; Fleming, Leigh; Elrawemi, Mohamed

2014-03-01

This paper reports on the recent work carried out as part of the EU funded NanoMend project. The project seeks to develop integrated process inspection, cleaning, repair and control systems for nano-scale thin films on large area substrates. In the present study flexible photovoltaic films have been the substrate of interest. Flexible PV films are the subject of significant development at present and the latest films have efficiencies at or beyond the level of Si based rigid PV modules. These flexible devices are fabricated on polymer film by the repeated deposition, and patterning, of thin layer materials using roll-to-roll processes, where the whole film is approximately 3um thick prior to encapsulation. Whilst flexible films offer significant advantages in terms of mass and the possibility of building integration (BIPV) they are at present susceptible to long term environmental degradation as a result of water vapor transmission through the barrier layers to the CIGS (Copper Indium Gallium Selenide CuInxGa(1-x)Se2) PV cells thus causing electrical shorts and efficiency drops. Environmental protection of the GIGS cell is provided by a thin (40nm) barrier coating of Al2O3. The highly conformal aluminium oxide barrier layer is produced by atomic layer deposition (ALD) where, the ultra-thin Al2O3 layer is deposited onto polymer thin films before these films encapsulate the PV cell. The surface of the starting polymer film must be of very high quality in order to avoid creating defects in the device layers. Since these defects reduce manufacturing yield, in order to prevent them, a further thin polymer coating (planarization layer) is generally applied to the polymer film prior to deposition. The presence of surface irregularities on the uncoated film can create defects within the nanometre-scale, aluminium oxide, barrier layer and these are measured and characterised. This paper begins by reporting the results of early stage measurements conducted to characterise the uncoated and coated polymer film surface topography using feature parameter analysis. The measurements are carried out using a Taylor Hobson Coherence Correlation Interferometer an optical microscope and SEM. Feature parameter analysis allows the efficient separation of small insignificant defects from large defects. The presence of both large and insignificant defects is then correlated with the water vapour transmission rate as measured on representative sets of films using at standard MOCON test. The paper finishes by drawing conclusions based on analysis of WVTR and defect size, where it is postulated that small numbers of large defects play a significant role in higher levels of WVTR.

Effect of wind speed on performance of a solar-pv array

USDA-ARS?s Scientific Manuscript database

Thousands of solar photovoltaic (PV) arrays have been installed over the past few years, but the effect of wind speed on the predicted performance of PV arrays is not usually considered by installers. An increase in wind speed will cool the PV array, and the electrical power of the PV modules will ...

Using PVFORM, a systems performance model, to determine optimum mounting configurations for flat-plate photovoltaic modules

NASA Astrophysics Data System (ADS)

Menicucci, D. F.

The performance of a photovoltaic (PV) system is affected by the particular mounting configuration selected. But the optimal configuration for various potential designs is unknown because too few PV systems have been fielded. Sandia National Laboratories (SNLA) is currently conducting a controlled field experiment in which four of the most commonly used module mounting configurations are being compared. The data from the experiment are used to verify the accuracy of PVFORM, a new PV performance model. The model is then used to simulate the performance of PV modules mounted in different configurations in eight sites throughtout the U.S. The module mounting configurations, the experimental methods used, the specialized statistical techniques used in the analysis and the final results of the effort are described. The module mounting configurations are rank ordered at each site according to their energy production performane and each is briefly discussed in terms of its advantages or disadvantages in various applications.

Experiences of a grid connected solar array energy production

NASA Astrophysics Data System (ADS)

Hagymássy, Zoltán; Vántus, András

2015-04-01

Solar energy possibilities of Hungary are higher than in Central Europe generally. The Institute for Land Utilisation, Technology and Regional Development of the University of Debrecen installed a photovoltaic (PV) system. The PV system is structured into 3 subsystems (fields). The first subsystem has 24 pieces of Kyocera KC 120 W type modules, the second subsystem has 72 pieces of Siemens ST 40W, and the remaining has 72 pieces of Dunasolar DS 40W In order to be operable independently of each other three inverter modules (SB 2500) had been installed. The recorder can be connected directly to a desktop PC. Operating and meteorological dates are recorded by MS Excel every 15 minutes. The power plant is connected to a weather station, which contents a PT 100 type temperature and humidity combined measuring instrument, a CM 11 pyranometer, and a wind speed measuring instrument. The produced DC, and AC power, together with the produced energy are as well, and the efficiency can be determined for each used PV technology. The measured operating and meteorological dates are collected by Sunny Boy Control, produced by the SMA. The energy productions of the subsystems are measured continually and the subsystems are measured separately. As an expected, the produced energy of polycrystalline -Si PV module and monocrystalline -Si PV was higher than amorphous-Si PV module. It is well known that energy analysis is more suitable for energy balance when we design a system. The air temperature and the temperature of the panels and the global irradiation conditions were measured. In summertime the panel temperature reaches 60-80 degrees in a sunny day. The panel temperatures are in a spring sunny day approximately 30-40 degrees. It can be concluded that the global irradiation is a major impact feature to influence the amount of energy produced. The efficiency depends on several parameters (spectral distribution of the incoming light, temperature values, etc.). The energy efficiency of a PV system in general can be defined as the ratio of the output energy of the system to the input energy received on the photovoltaic surface. As an expected, the energy efficiencies of polycrystalline -Si PV module and monocrystalline -Si PV was higher than amorphous-Si PV module. Based on our study, in general it can be concluded that the energy efficiency is lower than theoretical.

A circuit-based photovoltaic module simulator with shadow and fault settings

NASA Astrophysics Data System (ADS)

Chao, Kuei-Hsiang; Chao, Yuan-Wei; Chen, Jyun-Ping

2016-03-01

The main purpose of this study was to develop a photovoltaic (PV) module simulator. The proposed simulator, using electrical parameters from solar cells, could simulate output characteristics not only during normal operational conditions, but also during conditions of partial shadow and fault conditions. Such a simulator should possess the advantages of low cost, small size and being easily realizable. Experiments have shown that results from a proposed PV simulator of this kind are very close to that from simulation software during partial shadow conditions, and with negligible differences during fault occurrence. Meanwhile, the PV module simulator, as developed, could be used on various types of series-parallel connections to form PV arrays, to conduct experiments on partial shadow and fault events occurring in some of the modules. Such experiments are designed to explore the impact of shadow and fault conditions on the output characteristics of the system as a whole.

Sensitivities of projected 1980 photovoltaic system costs to major system cost drivers

NASA Technical Reports Server (NTRS)

Zimmerman, L. W.; Smith, J. L.

1984-01-01

The sensitivity of projected 1990 photovoltaic (PV) system costs to major system cost drivers was examined. It includes: (1) module costs and module efficiencies; (2) area related balance of system (BOS) costs; (3) inverter costs and efficiencies; and (4) module marketing and distribution markups and system integration fees. Recent PV system cost experiences and the high costs of electricity from the systems are reviewed. The 1990 system costs are projected for five classes of PV systems, including four ground mounted 5-MWp systems and one residential 5-kWp system. System cost projections are derived by first projecting costs and efficiencies for all subsystems and components. Sensitivity analyses reveal that reductions in module cost and engineering and system integration fees seem to have the greatest potential for contributing to system cost reduction. Although module cost is clearly the prime candidate for fruitful PV research and development activities, engineering and system integration fees seem to be more amenable to reduction through appropriate choice of system size and market strategy. Increases in inverter and module efficiency yield significant benefits, especially for systems with high area related costs.

Effect of Thermoelectric Cooling (TEC) module and the water flow heatsink on Photovoltaic (PV) panel performance

NASA Astrophysics Data System (ADS)

Amelia, A. R.; Jusoh, MA; Shamira Idris, Ida

2017-11-01

Photovoltaic (PV) panel suffers in low conversion efficiency of the output performance affected by the elevated operating temperature of the PV panel. It is important to keep the PV panel to operate at low temperature. To address this issue, this paper proposes the cooling system using thermoelectric cooling (TEC) and water block heatsink for enhancing the PV panel output performance. These both types cooling system were designed located on the back side of the PV panel to cool down the operating temperature of the PV panel. To evaluate the function for the existing cooling systems, the experiment was subsequently performed for PV panel without and with different design of the cooling system in outdoor weather conditions. By comparing the experimental results, it is concluded that by the hybrid cooling system which combining TEC module and the water block heatsink could improve the output performance of the PV panel. By the reduction temperature of the PV panel by 16.04 %, the average output power of the PV panel has been boosted up from 8.59 W to 9.03 W. In short, the output power of the PV panel was enhanced by the reduction of the operating temperature of the PV panel.

NREL Photovoltaic Program. FY 1994 annual report, October 1, 1993--September 30, 1994

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

NONE

1995-06-01

This report summarizes the in-house and subcontracted research and development activities under the National renewable Energy Laboratory (NREL) Photovoltaics (PV) program for fiscal year 1994. Research is organized under the following areas; PV program management; crystalline silicon and advanced devices; thin-film PV technologies; PV manufacturing; PV module and system performance and engineering; and PV applications and markets.

Analysis of twelve-month degradation in three polycrystalline photovoltaic modules

NASA Astrophysics Data System (ADS)

Lai, T.; Potter, B. G.; Simmons-Potter, K.

2016-09-01

Polycrystalline silicon photovoltaic (PV) modules have the advantage of lower manufacturing cost as compared to their monocrystalline counterparts, but generally exhibit both lower initial module efficiencies and more significant early-stage efficiency degradation than do similar monocrystalline PV modules. For both technologies, noticeable deterioration in power conversion efficiency typically occurs over the first two years of usage. Estimating PV lifetime by examining the performance degradation behavior under given environmental conditions is, therefore, one of continual goals for experimental research and economic analysis. In the present work, accelerated lifecycle testing (ALT) on three polycrystalline PV technologies was performed in a full-scale, industrial-standard environmental chamber equipped with single-sun irradiance capability, providing an illumination uniformity of 98% over a 2 x 1.6m area. In order to investigate environmental aging effects, timedependent PV performance (I-V characteristic) was evaluated over a recurring, compressed day-night cycle, which simulated local daily solar insolation for the southwestern United States, followed by dark (night) periods. During a total test time of just under 4 months that corresponded to a year equivalent exposure on a fielded module, the temperature and humidity varied in ranges from 3°C to 40°C and 5% to 85% based on annual weather profiles for Tucson, AZ. Removing the temperature de-rating effect that was clearly seen in the data enabled the computation of normalized efficiency degradation with time and environmental exposure. Results confirm the impact of environmental conditions on the module long-term performance. Overall, more than 2% efficiency degradation in the first year of usage was observed for all thee polycrystalline Si solar modules. The average 5-year degradation of each PV technology was estimated based on their determined degradation rates.

Singing modulates parvalbumin interneurons throughout songbird forebrain vocal control circuitry

PubMed Central

Zengin-Toktas, Yildiz

2017-01-01

Across species, the performance of vocal signals can be modulated by the social environment. Zebra finches, for example, adjust their song performance when singing to females (‘female-directed’ or FD song) compared to when singing in isolation (‘undirected’ or UD song). These changes are salient, as females prefer the FD song over the UD song. Despite the importance of these performance changes, the neural mechanisms underlying this social modulation remain poorly understood. Previous work in finches has established that expression of the immediate early gene EGR1 is increased during singing and modulated by social context within the vocal control circuitry. Here, we examined whether particular neural subpopulations within those vocal control regions exhibit similar modulations of EGR1 expression. We compared EGR1 expression in neurons expressing parvalbumin (PV), a calcium buffer that modulates network plasticity and homeostasis, among males that performed FD song, males that produced UD song, or males that did not sing. We found that, overall, singing but not social context significantly affected EGR1 expression in PV neurons throughout the vocal control nuclei. We observed differences in EGR1 expression between two classes of PV interneurons in the basal ganglia nucleus Area X. Additionally, we found that singing altered the amount of PV expression in neurons in HVC and Area X and that distinct PV interneuron types in Area X exhibited different patterns of modulation by singing. These data indicate that throughout the vocal control circuitry the singing-related regulation of EGR1 expression in PV neurons may be less influenced by social context than in other neuron types and raise the possibility of cell-type specific differences in plasticity and calcium buffering. PMID:28235074

NREL to Host Ninth Annual PV Reliability Workshop | News | NREL

Science.gov Websites

share research leading to more durable and reliable PV modules, thus reducing the cost of solar to Host Ninth Annual PV Reliability Workshop NREL to Host Ninth Annual PV Reliability Workshop their results during a poster session at the 2017 PV Reliability Workshop. 4 people consult two

Emerging photovoltaic technologies: Environmental and health issues update

NASA Astrophysics Data System (ADS)

Fthenakis, Vasilis M.; Moskowitz, Paul D.

1997-02-01

New photovoltaic (PV) technologies promise low-cost, reliable PV modules and have the potential for significant PV penetration into the energy market. These prospects for commercialization have attracted renewed interest in the advantageous environmental impact of using PV and also in the potential environmental, health and safety (EHS) burdens in PV manufacturing and decommissioning. In this paper, we highlight recent studies on EHS issues: a) An integrated energy-environmental-economic analysis which shows that large-scale use of PV can significantly contribute to alleviating the greenhouse effect; in the United States alone, it could displace 450 million tons of carbon emissions by the year 2030, b) Recycling of the spent modules and scarp is economically feasible; current research centers on improving the efficiency and economics of recycling CdTe and CIS modules, c) Toxicological studies conducted by the National Institute of Environmental Health Sciences (NIEHS) compared the acute toxicity of CdTe, CIS, and CGS; CdTe was the most toxic, and CGS the least toxic of the three. Additional studies are now comparing the systemic toxicity of these compounds with the toxicity of their precursors.

Progress & Frontiers in PV Performance

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

Deline, Chris; DiOrio, Nick; Jordan, Dirk

2016-09-12

PowerPoint slides for a presentation given at Solar Power International 2016. Presentation includes System Advisor Model (SAM) introduction and battery modeling, bifacial PV modules and modeling, shade modeling and module level power electronics (MLPE), degradation rates, and PVWatts updates and validation.

An opportune and unique research to evaluate the public health impact of electronic cigarettes.

PubMed

Besaratinia, Ahmad; Tommasi, Stella

2017-10-01

In response to the growing public health concern regarding the risks or benefits of electronic cigarettes (e-cig) use relative to smoking, the National Institute on Drug Abuse (NIDA) has recently introduced the first standardized- and well- characterized e-cig device to the research community (see, https://www.drugabuse.gov/funding/supplemental-information-nida-e-cig ). E-cig are promoted as safe alternatives to conventional tobacco cigarettes and/or as aides to smoking cessation. E-cig are highly popular among cigarette smokers who are unable/unwilling to quit but are willing to switch to putatively less-harmful tobacco substitutes. E-cig are also becoming increasingly popular among youth who have never experimented with combustible cigarettes. However, chemical analyses of e-cig juices (both in liquid form and after being heated into vapor) have shown that many carcinogens present in cigarette smoke are also found in a range of e-cig products. To date, the cancer-causing potential of e-cig has not been investigated in e-cig users (i.e., vapers). Use of e-cig without a prior history of smoking is currently a rare phenomenon in adults, but is increasingly common among youth. Consequently, investigating the carcinogenic potential of e-cig in nonsmoking youth provides a unique opportunity to verify the health impact of e-cig use, without the confounding effects of cigarette smoking. Within this context, the availability of the NIDA Standard Research e-cig offers a unique research opportunity with tremendous public health implications. Comparing and contrasting the cancer-causing potentials of standard vaping and smoking in youth will help determine the health risks or benefits of e-cig use relative to cigarette smoking. This information will be instrumental in making scientifically based decisions on the development and evaluation of policies and regulations on e-cig manufacture, marketing, and distribution. Ultimately, evidence-based guidelines and legislations on e-cig will help reduce the burden of tobacco-related diseases, particularly on minors and vulnerable populations.

Photovoltaics: Energy for the New Millenium

NASA Astrophysics Data System (ADS)

Surek, Thomas

2000-04-01

Photovoltaics (PV) is a semiconductor-based technology that directly converts sunlight to electricity. The stimulus for terrestrial PV started more than 25 years ago in response to the oil crises of the 1970s, which resulted in major government programs in the United States, Europe, Japan, and elsewhere. Ongoing concerns with the global environment, as well as the worldwide efforts to seek alternate, indigenous sources of energy, continue to drive the investment in PV research and deployment. Today, the manufacture, sale, and use of PV has become a billion-dollar industry worldwide, with nearly 200 megawatts (MW) of PV modules shipped in 1999. The twenty five years of research and development led to the discovery of new PV materials, devices, and fabrication approaches; continuing improvements in the efficiency and reliability of solar cells and modules; and lower PV module and system costs. This talk reviews the rapid progress that has occurred in PV technology from the laboratory to the marketplace, including reviews of the leading technology options, status and issues, and key industry players. New processes for fabricating PV materials and devices, and innovative PV approaches with low-cost potential are elements of an ongoing research program aimed at future advancements in PV cost and performance While major market opportunities continue to exist in the developing countries, where sizable populations are without any electricity, today's manufacturing expansions are fueled by market initiatives for grid-connected PV in residential and commercial buildings. The combinations of increased production capacities, with the attendant cost reductions as a result of economies of scale, are expected to lead to sustainable markets. A key to achieving the ultimate potential of PV is to continue to increase the sunlight-to-electricity conversion efficiencies and translate the laboratory successes to cost-competitive products. Building a robust technology base is essential to overcoming this high-risk transition. Then PV will make a globally significant contribution to our energy supply and environment.

System and method for design and optimization of grid connected photovoltaic power plant with multiple photovoltaic module technologies

DOEpatents

Thomas, Bex George; Elasser, Ahmed; Bollapragada, Srinivas; Galbraith, Anthony William; Agamy, Mohammed; Garifullin, Maxim Valeryevich

2016-03-29

A system and method of using one or more DC-DC/DC-AC converters and/or alternative devices allows strings of multiple module technologies to coexist within the same PV power plant. A computing (optimization) framework estimates the percentage allocation of PV power plant capacity to selected PV module technologies. The framework and its supporting components considers irradiation, temperature, spectral profiles, cost and other practical constraints to achieve the lowest levelized cost of electricity, maximum output and minimum system cost. The system and method can function using any device enabling distributed maximum power point tracking at the module, string or combiner level.

2017 NREL Photovoltaic Reliability Workshop

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

Kurtz, Sarah

NREL's Photovoltaic (PV) Reliability Workshop (PVRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology -- both critical goals for moving PV technologies deeper into the electricity marketplace.

In-situ comparison of thermal measurement technologies for interpretation of PV module temperature de-rating effects

NASA Astrophysics Data System (ADS)

Elwood, Teri; Bennett, Whit; Lai, Teh; Simmons-Potter, Kelly

2016-09-01

It is well known that the efficiency of a photovoltaic (PV) module is strongly impacted by its temperature such that higher temperatures lead to lower energy conversion efficiencies. An accurate measurement of the temperature de-rating effect, therefore, is vital to the correct interpretation of PV module performance under varied environmental conditions. The current work investigates and compares methods for performing measurements of module temperature both in the lab and in field-test environments. A comparison of several temperature measurement devices was made in order to establish the ideal sensor configuration for quantifying module operating temperature. Sensors were also placed in various locations along a string of up to eight photovoltaic modules to examine the variance in operating temperature with position in the string and within a larger array of strings.

Comparison of modeled and experimental PV array temperature profiles for accurate interpretation of module performance and degradation

NASA Astrophysics Data System (ADS)

Elwood, Teri; Simmons-Potter, Kelly

2017-08-01

Quantification of the effect of temperature on photovoltaic (PV) module efficiency is vital to the correct interpretation of PV module performance under varied environmental conditions. However, previous work has demonstrated that PV module arrays in the field are subject to significant location-based temperature variations associated with, for example, local heating/cooling and array edge effects. Such thermal non-uniformity can potentially lead to under-prediction or over-prediction of PV array performance due to an incorrect interpretation of individual module temperature de-rating. In the current work, a simulated method for modeling the thermal profile of an extended PV array has been investigated through extensive computational modeling utilizing ANSYS, a high-performance computational fluid dynamics (CFD) software tool. Using the local wind speed as an input, simulations were run to determine the velocity at particular points along modular strings corresponding to the locations of temperature sensors along strings in the field. The point velocities were utilized along with laminar flow theories in order to calculate Nusselt's number for each point. These calculations produced a heat flux profile which, when combined with local thermal and solar radiation profiles, were used as inputs in an ANSYS Thermal Transient model that generated a solar string operating temperature profile. A comparison of the data collected during field testing, and the data fabricated by ANSYS simulations, will be discussed in order to authenticate the accuracy of the model.

When PV modules are becoming real building elements: White solar module, a revolution for BIPV (Presentation Recording)

NASA Astrophysics Data System (ADS)

Perret-Aebi, Laure-Emmanuelle; Escarré, Jordi; Li, Heng-Yu; Sansonnens, Laurent; Galliano, Federico; Cattaneo, Gianluca; Heinstein, Patrick; Nicolay, Sylvain; Bailat, Julien; Eberhard, Sébastien; Ballif, Christophe

2015-09-01

The use of photovoltaic (PV) is not anymore an option but a real need in the construction of nearly zero energy buildings. To date, the lack of PV products specifically designed for building integration, considering aesthetics and architectural aspects, is one important limiting factor allowing a massive deployment of PV in the built environment. Architects are continuously asking for new solutions to customize the colour of PV elements to better integrate them into the building skin. Among these colours, white is especially attractive as it is widely used in architecture for its elegance, versatility and fresh look. Until now, white solar modules were not considered to be an option and even never been though to be a technological possibility. Nonetheless, CSEM recently developed a new technology to make white solar modules a reality. Furthermore, the new Swiss company called Solaxess is now working on the industrialisation of this very innovative technology and the first products are expecting to be on the market at the end of 2015. The technology is based on the combination of two different elements: a solar cell able to convert solar infrared light into electricity and a selective filter which reflects and diffuse the whole visible spectrum. Any PV technology based on crystalline silicon can be used as they have a good response in the infrared. Approximately 55% of the current generated under standard test conditions comes from the infrared leading to conversion efficiencies above 11%. We will demonstrate, that thanks to this very innovative technology PV modules can become attractive and real active building elements and therefore meets the requirements of any future energy management through advanced building skins.

Exposure to Electronic Cigarettes Impairs Pulmonary Anti-Bacterial and Anti-Viral Defenses in a Mouse Model

PubMed Central

Sussan, Thomas E.; Gajghate, Sachin; Thimmulappa, Rajesh K.; Ma, Jinfang; Kim, Jung-Hyun; Sudini, Kuladeep; Consolini, Nicola; Cormier, Stephania A.; Lomnicki, Slawo; Hasan, Farhana; Pekosz, Andrew; Biswal, Shyam

2015-01-01

Electronic cigarettes (E-cigs) have experienced sharp increases in popularity over the past five years due to many factors, including aggressive marketing, increased restrictions on conventional cigarettes, and a perception that E-cigs are healthy alternatives to cigarettes. Despite this perception, studies on health effects in humans are extremely limited and in vivo animal models have not been generated. Presently, we determined that E-cig vapor contains 7x1011 free radicals per puff. To determine whether E-cig exposure impacts pulmonary responses in mice, we developed an inhalation chamber for E-cig exposure. Mice that were exposed to E-cig vapor contained serum cotinine concentrations that are comparable to human E-cig users. E-cig exposure for 2 weeks produced a significant increase in oxidative stress and moderate macrophage-mediated inflammation. Since, COPD patients are susceptible to bacterial and viral infections, we tested effects of E-cigs on immune response. Mice that were exposed to E-cig vapor showed significantly impaired pulmonary bacterial clearance, compared to air-exposed mice, following an intranasal infection with Streptococcus pneumonia. This defective bacterial clearance was partially due to reduced phagocytosis by alveolar macrophages from E-cig exposed mice. In response to Influenza A virus infection, E-cig exposed mice displayed increased lung viral titers and enhanced virus-induced illness and mortality. In summary, this study reports a murine model of E-cig exposure and demonstrates that E-cig exposure elicits impaired pulmonary anti-microbial defenses. Hence, E-cig exposure as an alternative to cigarette smoking must be rigorously tested in users for their effects on immune response and susceptibility to bacterial and viral infections. PMID:25651083

Parental Use of Electronic Cigarettes.

PubMed

Garbutt, Jane M; Miller, Whitney; Dodd, Sherry; Bobenhouse, Neil; Sterkel, Randall; Strunk, Robert C

2015-01-01

To describe parental use of electronic cigarettes (e-cigs) to better understand the safety risks posed to children. Between June 24 and November 6, 2014, parents completed a self-administered paper survey during an office visit to 15 pediatric practices in a Midwestern practice-based research network. Attitudes towards and use of e-cigs are reported for those aware of e-cigs before the survey. Ninety-five percent (628 of 658) of respondents were aware of e-cigs. Of these, 21.0% (130 of 622) had tried e-cigs at least once, and 12.3% (77) reported e-cig use by ≥1 person in their household (4.0% exclusive e-cig use, 8.3% dual use with regular cigarettes). An additional 17.3% (109) reported regular cigarette use. Most respondents from e-cig-using homes did not think e-cigs were addictive (36.9% minimally or not addictive, 25.0% did not know). While 73.7% believed that e-liquid was very dangerous for children if they ingested it, only 31.2% believed skin contact to be very dangerous. In 36.1% of e-cig-using homes, neither childproof caps nor locks were used to prevent children's access to e-liquid. Only 15.3% reported their child's pediatrician was aware of e-cig use in the home. E-cig use occurred in 1 in 8 homes, often concurrently with regular cigarettes. Many parents who used e-cigs were unaware of the potential health and safety hazards, including nicotine poisoning for children, and many did not store e-liquid safely. Pediatricians could provide education about e-cig associated safety hazards but are unaware of e-cig use in their patients' homes. Copyright © 2015 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

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.

Computer Drawing Method for Operating Characteristic Curve of PV Power Plant Array Unit

NASA Astrophysics Data System (ADS)

Tan, Jianbin

2018-02-01

According to the engineering design of large-scale grid-connected photovoltaic power stations and the research and development of many simulation and analysis systems, it is necessary to draw a good computer graphics of the operating characteristic curves of photovoltaic array elements and to propose a good segmentation non-linear interpolation algorithm. In the calculation method, Component performance parameters as the main design basis, the computer can get 5 PV module performances. At the same time, combined with the PV array series and parallel connection, the computer drawing of the performance curve of the PV array unit can be realized. At the same time, the specific data onto the module of PV development software can be calculated, and the good operation of PV array unit can be improved on practical application.

Growth and characterization of CdS buffer layers by CBD and MOCVD

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

Morrone, A.A.; Huang, C.; Li, S.S.

1999-03-01

Thin film CdS has been widely used in thin-film photovoltaic devices. The most efficient Cu(In,&hthinsp;Ga)Se{sub 2} (CIGS) solar cells reported to date utilized a thin CdS buffer layer prepared by a reactive solution growth technique known as chemical bath deposition (CBD). Considerable effort has been directed to better understand the role and find a replacement for the CBD CdS process in CIGS-based solar cells. We reported a low temperature ({approximately}150&hthinsp;{degree}C) Metalorganic Chemical Vapor Deposition (MOCVD) CdS thin film buffer layer process for CIGS absorbers. Many prior studies have reported that CBD CdS contains a mixture of crystal structures. Recent investigationsmore » of CBD CdS thin films by ellipsometry suggested a multilayer structure. In this study we compare CdS thin films prepared by CBD and MOCVD and the effects of annealing. TED and XRD are used to characterize the crystal structure, the film microstructure is studied by HRTEM, and the optical properties are studied by Raman and spectrophotometry. All of these characterization techniques reveal superior crystalline film quality for CdS films grown by MOCVD compared to those grown by CBD. Dual Beam Optical Modulation (DBOM) studies showed that the MOCVD and CBD CdS buffer layer processes have nearly the same effect on CIGS absorbers when combined with a cadmium partial electrolyte aqueous dip. {copyright} {ital 1999 American Institute of Physics.}« less

Photovoltaic Materials

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

Duty, C.; Angelini, J.; Armstrong, B.

The goal of the current project was to help make the US solar industry a world leader in the manufacture of thin film photovoltaics. The overall approach was to leverage ORNL’s unique characterization and processing technologies to gain a better understanding of the fundamental challenges for solar cell processing and apply that knowledge to targeted projects with industry members. ORNL has the capabilities in place and the expertise required to understand how basic material properties including defects, impurities, and grain boundaries affect the solar cell performance. ORNL also has unique processing capabilities to optimize the manufacturing process for fabrication ofmore » high efficiency and low cost solar cells. ORNL recently established the Center for Advanced Thin-film Systems (CATS), which contains a suite of optical and electrical characterization equipment specifically focused on solar cell research. Under this project, ORNL made these facilities available to industrial partners who were interested in pursuing collaborative research toward the improvement of their product or manufacturing process. Four specific projects were pursued with industrial partners: Global Solar Energy is a solar industry leader in full scale production manufacturing highly-efficient Copper Indium Gallium diSelenide (CIGS) thin film solar material, cells and products. ORNL worked with GSE to develop a scalable, non-vacuum, solution technique to deposit amorphous or nanocrystalline conducting barrier layers on untextured stainless steel substrates for fabricating high efficiency flexible CIGS PV. Ferro Corporation’s Electronic, Color and Glass Materials (“ECGM”) business unit is currently the world’s largest supplier of metallic contact materials in the crystalline solar cell marketplace. Ferro’s ECGM business unit has been the world's leading supplier of thick film metal pastes to the crystalline silicon PV industry for more than 30 years, and has had operational cells and modules in the field for 25 years. Under this project, Ferro leveraged world leading analytical capabilities at ORNL to characterize the paste-to-silicon interface microstructure and develop high efficiency next generation contact pastes. Ampulse Corporation is developing a revolutionary crystalline-silicon (c-Si) thin-film solar photovoltaic (PV) technology. Utilizing uniquely-textured substrates and buffer materials from the Oak Ridge National Laboratory (ORNL), and breakthroughs in Hot-Wire Chemical Vapor Deposition (HW-CVD) techniques in epitaxial silicon developed at the National Renewable Energy Laboratory (NREL), Ampulse is creating a solar technology that is tunable in silicon thickness, and hence in efficiency and economics, to meet the specific requirements of multiple solar PV applications. This project focused on the development of a high rate deposition process to deposit Si, Ge, and Si1-xGex films as an alternate to hot-wire CVD. Mossey Creek Solar is a start-up company with great expertise in the solar field. The primary interest is to create and preserve jobs in the solar sector by developing high-yield, low-cost, high-efficiency solar cells using MSC-patented and -proprietary technologies. The specific goal of this project was to produce large grain formation in thin, net-shape-thickness mc-Si wafers processed with high-purity silicon powder and ORNL's plasma arc lamp melting without introducing impurities that compromise absorption coefficient and carrier lifetime. As part of this project, ORNL also added specific pieces of equipment to enhance our ability to provide unique insight for the solar industry. These capabilities include a moisture barrier measurement system, a combined physical vapor deposition and sputtering system dedicated to cadmium-containing deposits, adeep level transient spectroscopy system useful for identifying defects, an integrating sphere photoluminescence system, and a high-speed ink jet printing system. These tools were combined with others to study the effect of defects on the performance of crystalline silicon and thin film solar cells, to explore non-vacuum ink-based approaches to solar cell production, as well as large-scale and low-cost deposition and processing of thin film CdTe material.« less

Plug and Play PV Systems for American Homes

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

Hoepfner, Christian

2016-12-22

The core objectives of the Plug & Play PV Systems Project were to develop a PV system that can be installed on a residential rooftop for less than $1.50/W in 2020, and in less than 10 hours (from point of purchase to commissioning). The Fraunhofer CSE team’s approach to this challenge involved a holistic approach to system design – hardware and software – that make Plug & Play PV systems: • Quick, easy, and safe to install • Easy to demonstrate as code compliant • Permitted, inspected, and interconnected via an electronic process Throughout the three years of work duringmore » this Department of Energy SunShot funded project, the team engaged in a substantive way with inspectional services departments and utilities, manufacturers, installers, and distributors. We received iterative feedback on the system design and on ideas for how such systems can be commercialized. This ultimately led us to conceiving of Plug & Play PV Systems as a framework, with a variety of components compatible with the Plug & Play PV approach, including string or microinverters, conventional modules or emerging lightweight modules. The framework enables a broad group of manufacturers to participate in taking Plug & Play PV Systems to market, and increases the market size for such systems. Key aspects of the development effort centered on the system hardware and associated engineering work, the development of a Plug & Play PV Server to enable the electronic permitting, inspection and interconnection process, understanding the details of code compliance and, on occasion, supporting applications for modifications to the code to allow lightweight modules, for example. We have published a number of papers on our testing and assessment of novel technologies (e.g., adhered lightweight modules) and on the electronic architecture.« less

The Capital Intensity of Photovoltaics Manufacturing

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

Basore, Paul

2015-10-19

Factory capital expenditure (capex) for photovoltaic (PV) module manufacturing strongly influences the per-unit cost of a c-Si module. This provides a significant opportunity to address the U.S. DOE SunShot module price target through capex innovation. Innovation options to reduce the capex of PV manufacturing include incremental and disruptive process innovation with c-Si, platform innovations, and financial approaches. and financial approaches.

Microinverter Thermal Performance in the Real-World: Measurements and Modeling

PubMed Central

Hossain, Mohammad Akram; Xu, Yifan; Peshek, Timothy J.; Ji, Liang; Abramson, Alexis R.; French, Roger H.

2015-01-01

Real-world performance, durability and reliability of microinverters are critical concerns for microinverter-equipped photovoltaic systems. We conducted a data-driven study of the thermal performance of 24 new microinverters (Enphase M215) connected to 8 different brands of PV modules on dual-axis trackers at the Solar Durability and Lifetime Extension (SDLE) SunFarm at Case Western Reserve University, based on minute by minute power and thermal data from the microinverters and PV modules along with insolation and environmental data from July through October 2013. The analysis shows the strengths of the associations of microinverter temperature with ambient temperature, PV module temperature, irradiance and AC power of the PV systems. The importance of the covariates are rank ordered. A multiple regression model was developed and tested based on stable solar noon-time data, which gives both an overall function that predicts the temperature of microinverters under typical local conditions, and coefficients adjustments reecting refined prediction of the microinverter temperature connected to the 8 brands of PV modules in the study. The model allows for prediction of internal temperature for the Enphase M215 given similar climatic condition and can be expanded to predict microinverter temperature in fixed-rack and roof-top PV systems. This study is foundational in that similar models built on later stage data in the life of a device could reveal potential influencing factors in performance degradation. PMID:26147339

Performance enhancement in Sb doped Cu(InGa)Se2 thin film solar cell by e-beam evaporation

NASA Astrophysics Data System (ADS)

Chen, Jieyi; Shen, Honglie; Zhai, Zihao; Li, Yufang; Yi, Yunge

2018-03-01

To investigate the effects of Sb doping on the structural and electrical properties of Cu(InGa)Se2 (CIGS) thin films and solar cells, CIGS thin films, prepared by e-beam evaporation on soda-lime glass, were doped with lower and upper Sb layers in the precursor stacks respectively. Change of structure and introduction of stress were observed in the CIGS thin films with upper Sb layer in stack through XRD and Raman measurement. Both crystalline quality and compactness of CIGS thin films were improved by the doping of upper Sb layer in stack and the CIGS thin film showed an optimal structural property with 20 nm Sb layer. Movement of Fermi level of the surface of CIGS thin film after doping of upper Sb layer in stack and electrons transfer between Cu/Cu+ redox couple and CIGS thin films, which provided probability for the substitution of Sb for Cu sites at the surface of CIGS thin films, were proposed to explain the migration of Cu from the surface to the bulk of CIGS thin films. The larger barrier at the CIGS/CdS interface after doping of upper Sb layer in stack made contribution to the increase of VOC of CIGS solar cells. The efficiency of CIGS solar cell was improved from 3.3% to 7.2% after doping with 20 nm upper Sb. Compared to the CIGS solar cell with lower Sb layer in stack, in which an additional Cu2-xSe phase was found, the CIGS solar cell with upper Sb layer in stack possessed a higher efficiency.

Distinct Thalamic Reticular Cell Types Differentially Modulate Normal and Pathological Cortical Rhythms.

PubMed

Clemente-Perez, Alexandra; Makinson, Stefanie Ritter; Higashikubo, Bryan; Brovarney, Scott; Cho, Frances S; Urry, Alexander; Holden, Stephanie S; Wimer, Matthew; Dávid, Csaba; Fenno, Lief E; Acsády, László; Deisseroth, Karl; Paz, Jeanne T

2017-06-06

Integrative brain functions depend on widely distributed, rhythmically coordinated computations. Through its long-ranging connections with cortex and most senses, the thalamus orchestrates the flow of cognitive and sensory information. Essential in this process, the nucleus reticularis thalami (nRT) gates different information streams through its extensive inhibition onto other thalamic nuclei, however, we lack an understanding of how different inhibitory neuron subpopulations in nRT function as gatekeepers. We dissociated the connectivity, physiology, and circuit functions of neurons within rodent nRT, based on parvalbumin (PV) and somatostatin (SOM) expression, and validated the existence of such populations in human nRT. We found that PV, but not SOM, cells are rhythmogenic, and that PV and SOM neurons are connected to and modulate distinct thalamocortical circuits. Notably, PV, but not SOM, neurons modulate somatosensory behavior and disrupt seizures. These results provide a conceptual framework for how nRT may gate incoming information to modulate brain-wide rhythms. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Chapter 10.3: Reliability and Durability of PV Modules

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

Kurtz, Sarah

2017-01-07

Each year the world invests tens of billions of dollars or euros in PV systems with the expectation that these systems will last approximately 25 years. Although the disciplines of reliability, quality, and service life prediction have been well established for numerous products, a full understanding of these is currently challenging for PV modules because the desired service lifetimes are decades, preventing direct verification of lifetime predictions. A number of excellent reviews can be found in the literature summarizing the types of failures that are commonly observed for PV modules. This chapter discusses key failure/degradation mechanisms selected to highlight howmore » the kinetics of failure rates can and cannot be confidently predicted. For EVA-encapsulated modules, corrosion is observed to follow delamination, which then allows water droplets to directly contact the metallization. Extended test protocols such as Qualification Plus were created to address the known problems while standards groups update standard tests through the consensus process.« less

Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1−xGaxSe2 Growth: Indium-Gallium Selenide Co-Evaporation

PubMed Central

Pradhan, Puja; Aryal, Puruswottam; Attygalle, Dinesh; Ibdah, Abdel-Rahman; Koirala, Prakash; Li, Jian; Bhandari, Khagendra P.; Liyanage, Geethika K.; Ellingson, Randy J.; Heben, Michael J.; Marsillac, Sylvain; Collins, Robert W.; Podraza, Nikolas J.

2018-01-01

Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In1−xGax)2Se3 (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε1 − iε2, spectra. Here, RTSE has been used to obtain the (ε1, ε2) spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents (x) deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε1, ε2) spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x. From the resulting database of polynomial coefficients, the (ε1, ε2) spectra can be generated for any composition of IGS from the single parameter, x. The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε1, ε2) spectra have been interpreted as well in relation to observations from scanning electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy profiling analyses. Overall the structural, optical and compositional analysis possible by RTSE has assisted in understanding the growth and properties of three stage CIGS absorbers for solar cells and shows future promise for enhancing cell performance through monitoring and control. PMID:29337931

Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn1-xGaxSe₂ Growth: Indium-Gallium Selenide Co-Evaporation.

PubMed

Pradhan, Puja; Aryal, Puruswottam; Attygalle, Dinesh; Ibdah, Abdel-Rahman; Koirala, Prakash; Li, Jian; Bhandari, Khagendra P; Liyanage, Geethika K; Ellingson, Randy J; Heben, Michael J; Marsillac, Sylvain; Collins, Robert W; Podraza, Nikolas J

2018-01-16

Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In 1- x Ga x )₂Se₃ (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε₁ - iε₂, spectra. Here, RTSE has been used to obtain the (ε₁, ε₂) spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents ( x ) deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε₁, ε₂) spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x . From the resulting database of polynomial coefficients, the (ε₁, ε₂) spectra can be generated for any composition of IGS from the single parameter, x . The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε₁, ε₂) spectra have been interpreted as well in relation to observations from scanning electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy profiling analyses. Overall the structural, optical and compositional analysis possible by RTSE has assisted in understanding the growth and properties of three stage CIGS absorbers for solar cells and shows future promise for enhancing cell performance through monitoring and control.

Optical Physics of Cu(In,Ga)Se2 Solar Cells and Their Layer Components

NASA Astrophysics Data System (ADS)

Ibdah, Abedl-Rahman

Polycrystalline Cu(In1-xGax)Se 2 (CIGS) thin film technology has emerged as a promising candidate for low cost and high performance solar modules. The efficiency of CIGS solar cells is strongly influenced by several key factors. Among these factors include Ga composition and its profile in the absorber layer, copper content in this layer, and the solar cell multilayer structure. As a result, tools for the characterization of thin film CIGS solar cells and their layer components are becoming increasingly essential in research and manufacturing. Spectroscopic ellipsometry is a non-invasive technique that can serve as an accurate probe of component layer optical properties and multilayer structures, and can be applied as a diagnostic tool for real-time, in-line, and off-line monitoring and analysis in small area solar cell fabrication as well as in large area photovoltaics manufacturing. Implementation of spectroscopic ellipsometry provides unique insights into the properties of complete solar cell multilayer structures and their layer components. These insights can improve our understanding of solar cell structures, overcome challenges associated with solar cell fabrication, and assist in process monitoring and control on a production line. In this dissertation research, Cu(In,Ga)Se2 films with different Cu contents have been prepared by the one stage co-evaporation process. These films have been studied by real time spectroscopic ellipsometry (RTSE) during deposition, and by in-situ SE at the deposition temperature as well as at room temperature to extract the dielectric functions (epsilon1, epsilon 2) of the thin film materials. Analytical expressions for the room temperature dielectric functions were developed, and the free parameters that describe these analytical functions were in turn expressed as functions of the Cu content. As a result of this parameterization, the dielectric function spectra (epsilon 1, epsilon2) can be predicted for any desired composition within the range of the samples investigated. This capability was applied for mapping the structural and compositional variations of CIGS thin films deposited over a 10 cm x 10 cm substrate area. In another application presented in this dissertation, a non-invasive method utilizing ex-situ spectroscopic ellipsometry analysis has been developed and applied to determine non-destructively the Ga compositional profile in CIGS absorbers. The method employs parameterized dielectric function spectra (epsilon1, epsilon2) of CIGS versus Ga content to probe the compositional variation with depth into the absorber. In addition, a methodology for prediction of the external quantum efficiency (QE) including optical gains and losses for a CIGS solar cell has been developed. The methodology utilizes ex-situ spectroscopic ellipsometry analysis of a complete solar cell, with no free parameters, to deduce the multilayer solar cell structure non-invasively and simulate optical light absorption in each of the layer components. In the case of high efficiency CIGS solar cells, with minimal electronic losses, QE spectra are predicted from the sum of optical absorption in the active layer components. For such solar cells with ideal photo-generated charge carrier collection, the SE-predicted QE spectra are excellent representation of the measured ones. Since the QE spectra as well as the short circuit current density (Jsc) can be calculated directly from SE analysis results, then the predicted QE from SE can be compared with the experimental QE to evaluate electronic losses based on the difference between the spectra. Moreover, the calculated Jsc can be used as a key parameter for the design and optimization of anti-reflection coating structures. Because the long term production potential of CIGS solar modules may be limited by the availability of indium, it becomes important to reduce the thickness of the CIGS absorber layer. Thickness reduction would reduce the quantity of indium required for production which would in turn reduce costs. A decrease in short-circuit current density (Jsc) is expected, however, upon thinning the CIGS absorber due to incomplete absorption. To clarify the limits of obtainable Jsc in ultra-thin CIGS solar cells with Mo back contacts, optical properties and multilayer structural data are deduced via spectroscopic ellipsometry analysis and used to predict the QE spectra and maximum obtainable Jsc values upon thinning the absorber. Moreover, SE-guided optical design of ultra-thin CIGS solar cells has been demonstrated. In the case of solar cells fabricated on Mo, thinning the absorber in a CIGS solar cell is associated with significant optical losses in the Mo containing back contact layers. This is due in part to the poor optical reflectance of Mo. Such optical losses may be reduced by employing a back contact design with improved reflectance. Thus, alternative novel solar cell structures with ultra-thin absorbers and improved back contact reflectance have been designed and investigated using SE and the optical modeling methods. In addition to optical losses, electronic losses in the ultra-thin solar cells have been evaluated. By separating the absorber layer into sub-layer regions (for example, near-junction, bulk, and near-back-contact) and varying carrier collection probability in these regions, the contribution of each region to the current can be estimated. Based on this separation, the origin of the electronic losses has been identified as near the back contact.

U.S. Residential Photovoltaic (PV) System Prices, Q4 2013 Benchmarks: Cash Purchase, Fair Market Value, and Prepaid Lease Transaction Prices

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

Davidson, C.; James, T. L.; Margolis, R.

The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in global PV module prices. This report provides a Q4 2013 update for residential PV systems, based on an objective methodology that closely approximates the book value of a PV system. Several cases are benchmarked to represent common variation in business models, labor rates, and module choice. We estimate a weighted-average cash purchase price of $3.29/W for modeled standard-efficiency, polycrystalline-silicon residential PV systems installed in the United States. This is a 46% declinemore » from the 2013-dollar-adjusted price reported in the Q4 2010 benchmark report. In addition, this report frames the cash purchase price in the context of key price metrics relevant to the continually evolving landscape of third-party-owned PV systems by benchmarking the minimum sustainable lease price and the fair market value of residential PV systems.« less

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

NASA Technical Reports Server (NTRS)

Christensen, Elmer

1985-01-01

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

High-Efficiency Photovoltaic System Using Partially-Connected DC-DC Converter

NASA Astrophysics Data System (ADS)

Uno, Masatoshi; Kukita, Akio; Tanaka, Koji

Power conversion electronics for photovoltaic (PV) systems are desired to operate as efficiently as possible to exploit the power generated by PV modules. This paper proposes a novel PV system in which a dc-dc converter is partially connected to series-connected PV modules. The proposed system achieves high power-conversion efficiency by reducing the passing power and input/output voltages of the converter. The theoretical operating principle was experimentally validated. Resultant efficiency performances of the proposed and conventional systems demonstrated that the proposed system was more efficient in terms of power conversion though the identical converter was used for the both systems.

CZTSSe: Materials and Physics Challenges

NASA Astrophysics Data System (ADS)

Gunawan, Oki

2011-03-01

Thin-film photovoltaic (PV) technologies led by CdTe and Cu(In,Ga) Se 2 (CIGS) are enjoying growing market share, due to their high performance and cost competitiveness, in the quest for renewable energy for the future. However the reliance on non-earth abundant elements tellurium and indium in these technologies presents a potential obstacle to ultimate terawatt deployment. We recently demonstrated kesterite Cu 2 ZnSn(Se,S)4 (CZTSSe) solar cells, comprised of the earth abundant metals copper, zinc and tin, with world record efficiency of 9.7%. In this talk we present a comprehensive device characterization study that pinpoints the key performance bottlenecks in these cells. We find strong buffer-absorber interface recombination and low minority carrier lifetimes that limit the open circuit voltage and a high and diverging device series resistance at lower temperature that suggests a blocking back contact that may limit the fill factor. These findings help to identify key areas for improvement for these CZTSSe cells in the pursuit of a high performance terawatt-scalable PV technology. In collaboration with Teodor K. Todorov, Aaron Barkhouse, Kejia Wang, David B. Mitzi, Supratik Guha, IBM T J Watson Research Center.

On the Path to SunShot. The Role of Advancements in Solar Photovoltaic Efficiency, Reliability, and Costs

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

Woodhouse, Michael; Jones-Albertus, Rebecca; Feldman, David

2016-05-01

This report examines the remaining challenges to achieving the competitive photovoltaic (PV) costs and large-scale deployment envisioned under the U.S. Department of Energy's SunShot Initiative. Solar-energy cost reductions can be realized through lower PV module and balance-of-system (BOS) costs as well as improved system efficiency and reliability. Numerous combinations of PV improvements could help achieve the levelized cost of electricity (LCOE) goals because of the tradeoffs among key metrics like module price, efficiency, and degradation rate as well as system price and lifetime. Using LCOE modeling based on bottom-up cost analysis, two specific pathways are mapped to exemplify the manymore » possible approaches to module cost reductions of 29%-38% between 2015 and 2020. BOS hardware and soft cost reductions, ranging from 54%-77% of total cost reductions, are also modeled. The residential sector's high supply-chain costs, labor requirements, and customer-acquisition costs give it the greatest BOS cost-reduction opportunities, followed by the commercial sector, although opportunities are available to the utility-scale sector as well. Finally, a future scenario is considered in which very high PV penetration requires additional costs to facilitate grid integration and increased power-system flexibility--which might necessitate even lower solar LCOEs. The analysis of a pathway to 3-5 cents/kWh PV systems underscores the importance of combining robust improvements in PV module and BOS costs as well as PV system efficiency and reliability if such aggressive long-term targets are to be achieved.« less

Flexible packaging for PV modules

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.

2008-08-01

Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

A review of manufacturing metrology for improved reliability of silicon photovoltaic modules

NASA Astrophysics Data System (ADS)

Davis, Kristopher O.; Walters, Joseph; Schneller, Eric; Seigneur, Hubert; Brooker, R. Paul; Scardera, Giuseppe; Rodgers, Marianne P.; Mohajeri, Nahid; Shiradkar, Narendra; Dhere, Neelkanth G.; Wohlgemuth, John; Rudack, Andrew C.; Schoenfeld, Winston V.

2014-10-01

In this work, the use of manufacturing metrology across the supply chain to improve crystalline silicon (c-Si) photovoltaic (PV) module reliability and durability is addressed. Additionally, an overview and summary of a recent extensive literature survey of relevant measurement techniques aimed at reducing or eliminating the probability of field failures is presented. An assessment of potential gaps is also given, wherein the PV community could benefit from new research and demonstration efforts. This review is divided into three primary areas representing different parts of the c-Si PV supply chain: (1) feedstock production, crystallization and wafering; (2) cell manufacturing; and (3) module manufacturing.

Cd doping at PVD-CdS/CuInGaSe 2 heterojunctions

DOE PAGES

He, Xiaoqing; Paulauskas, Tadas; Ercius, Peter; ...

2017-02-20

In this paper, we report on direct evidence of Cd doping of the CuInGaSe 2 (CIGS) surface in physical vapor deposited (PVD) CdS/CIGS heterojunctions by scanning transmission electron microscopy (STEM) and related techniques. We find Cd doping of the CIGS near-surface region regardless of the presence or absence of Cu rich domains in the CdS for both zinc-blende (zb) and wurtzite (wz) CdS. However, we find that the Cd penetrates much farther into the CIGS when Cu-rich domains are present in the CdS. This suggests that Cu exchanges with Cd, increasing the concentration gradient for Cd in the CIGS andmore » thus driving Cd into the CIGS surface. The Cd doping is clearly resolved at atomic resolution in aberration-corrected STEM-high angle annular dark field images. In zb-CdS/CIGS heterojunctions, Cd is shown to substitute for both Cu and Ga atoms, while in wz-CdS/CIGS heterojunctions Cd seems to predominantly occupy Cu sites. Finally, Cd doping in the CIGS surface layer suggests the formation of a p-n homojunction in the CIGS, which may account for the high device efficiencies, comparable to CBD-CdS/CIGS processed structures.« less

Method of monolithic module assembly

DOEpatents

Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

1999-01-01

Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

Solar Electricity and Solar Fuels: Status and Perspectives in the Context of the Energy Transition.

PubMed

Armaroli, Nicola; Balzani, Vincenzo

2016-01-04

The energy transition from fossil fuels to renewables is already ongoing, but it will be a long and difficult process because the energy system is a gigantic and complex machine. Key renewable energy production data show the remarkable growth of solar electricity technologies and indicate that crystalline silicon photovoltaics (PV) and wind turbines are the workhorses of the first wave of renewable energy deployment on the TW scale around the globe. The other PV alternatives (e.g., copper/indium/gallium/selenide (CIGS) or CdTe), along with other less mature options, are critically analyzed. As far as fuels are concerned, the situation is significantly more complex because making chemicals with sunshine is far more complicated than generating electric current. The prime solar artificial fuel is molecular hydrogen, which is characterized by an excellent combination of chemical and physical properties. The routes to make it from solar energy (photoelectrochemical cells (PEC), dye-sensitized photoelectrochemical cells (DSPEC), PV electrolyzers) and then synthetic liquid fuels are presented, with discussion on economic aspects. The interconversion between electricity and hydrogen, two energy carriers directly produced by sunlight, will be a key tool to distribute renewable energies with the highest flexibility. The discussion takes into account two concepts that are often overlooked: the energy return on investment (EROI) and the limited availability of natural resources-particularly minerals-which are needed to manufacture energy converters and storage devices on a multi-TW scale. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microsystem enabled photovoltaic modules and systems

DOEpatents

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

2017-09-12

A photovoltaic (PV) module includes an absorber layer coupled to an optic layer. The absorber layer includes an array of PV elements. The optic layer includes a close-packed array of Keplerian telescope elements, each corresponding to one of an array of pupil elements. The Keplerian telescope substantially couple radiation that is incident on their objective surfaces into the corresponding pupil elements. Each pupil element relays radiation that is coupled into it from the corresponding Keplerian telescope element into the corresponding PV element.

Health professionals in Flanders perceive the potential health risks of vaping as lower than those of smoking but do not recommend using e-cigarettes to their smoking patients.

PubMed

Van Gucht, Dinska; Baeyens, Frank

2016-06-24

Many misperceptions of both risks and opportunities of e-cigarettes (e-cigs) exist among the general population and among physicians, although e-cigs could be a valuable harm reduction tool for current smokers. Two groups in Flanders, namely general practitioners (GPs; family doctors) and tobacco counselors filled out an online questionnaire with regard to their attitudes and risk perceptions concerning e-cigs. Statements included were on the safety and the addictive properties of e-cigs in absolute terms, whereas other items compared e-cigs with regular tobacco cigarettes. Statements about possible "gateway" and "renormalization" effects, selling to minors, and use in public places and on the potential of e-cigs as a smoking cessation aid were also included. Respondents were also asked for the rate at which their patients asked information about e-cigs, if they would recommend e-cigs to their smoking patients, and whether they had information brochures on e-cigs. About 70 % believed that e-cigs are harmful to vapers, and about half to two thirds believed that e-cigs are carcinogenic, increase cardiovascular risk, and increase the risk of chronic lung disease. Also, a substantial minority incorrectly believed these risks to be no less than those resulting from regular smoking. Ten to almost 20 % disagreed that e-cigs are healthier and represent less risk for the main serious smoking-related diseases than conventional cigarettes. More than half of the respondents disagreed that e-cigs are an effective smoking cessation aid. None (0 %) offered the strongest level of agreement for recommending e-cigs to their clients/patients, but GPs agreed to a lesser degree a bit more often than tobacco counselors. Almost none had information leaflets for potentially interested patients. Finally, the majority of our sample also believed that e-cigs will cause renormalization of smoking and that e-cigs will lead to an uptake of conventional smoking and disagreed with allowing vaping in enclosed public places. Health professionals in Flanders perceive the potential health risks of vaping as lower than those of smoking but do not recommend using e-cigs to their smoking patients.

Emissions from photovoltaic life cycles.

PubMed

Fthenakis, Vasilis M; Kim, Hyung Chul; Alsema, Erik

2008-03-15

Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004-2006, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions, and heavy metal emissions from four types of major commercial PV systems: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe and the United States during the materials and module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.

Ternary Precursors for Depositing I-III-VI2 Thin Films for Solar Cells via Spray CVD

NASA Technical Reports Server (NTRS)

Banger, K. K.; Hollingsworth, J. A.; Jin, M. H.-C.; Harris, J. D.; Duraj, S. A.; Smith, M.; Scheiman, D.; Bohannan, E. W.; Switzer, J. A.; Buhro, W. E.

2002-01-01

The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power (W/kg). Thin-film fabrication studies demonstrate that ternary single source precursors (SSP's) can be used in either a hot or cold-wall spray chemical vapour deposition (CVD) reactor, for depositing CuInS2, CuGaS2, and CuGaInS2 at reduced temperatures (400 to 450 C), which display good electrical and optical properties suitable for photovoltaic (PV) devices. X-ray diffraction studies, energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) confirmed the formation of the single phase CIS, CGS, CIGS thin-films on various substrates at reduced temperatures.

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

Hyaluronan and Layilin Mediate Loss of Airway Epithelial Barrier Function Induced by Cigarette Smoke by Decreasing E-cadherin*

PubMed Central

Forteza, Rosanna Malbran; Casalino-Matsuda, S. Marina; Falcon, Nieves S.; Valencia Gattas, Monica; Monzon, Maria E.

2012-01-01

Cigarette smoke (CigS) exposure is associated with increased bronchial epithelial permeability and impaired barrier function. Primary cultures of normal human bronchial epithelial cells exposed to CigS exhibit decreased E-cadherin expression and reduced transepithelial electrical resistance. These effects were mediated by hyaluronan (HA) because inhibition of its synthesis with 4-methylumbelliferone prevented these effects, and exposure to HA fragments of <70 kDa mimicked these effects. We show that the HA receptor layilin is expressed apically in human airway epithelium and that cells infected with lentivirus expressing layilin siRNAs were protected against increased permeability triggered by both CigS and HA. We identified RhoA/Rho-associated protein kinase (ROCK) as the signaling effectors downstream layilin. We conclude that HA fragments generated by CigS bind to layilin and signal through Rho/ROCK to inhibit the E-cadherin gene and protein expression, leading to a loss of epithelial cell-cell contact. These studies suggest that HA functions as a master switch protecting or disrupting the epithelial barrier in its high versus low molecular weight form and that its depolymerization is a first and necessary step triggering the inflammatory response to CigS. PMID:23048036

META-GLARE: a shell for CIG systems.

PubMed

Bottrighi, Alessio; Rubrichi, Stefania; Terenziani, Paolo

2015-01-01

In the last twenty years, many different approaches to deal with Computer-Interpretable clinical Guidelines (CIGs) have been developed, each one proposing its own representation formalism (mostly based on the Task-Network Model) execution engine. We propose META-GLARE a shell for easily defining new CIG systems. Using META-GLARE, CIG system designers can easily define their own systems (basically by defining their representation language), with a minimal programming effort. META-GLARE is thus a flexible and powerful vehicle for research about CIGs, since it supports easy and fast prototyping of new CIG systems.

Maximum Power Point tracking charge controllers for telecom applications -- Analysis and economics

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

Wills, R.H.

Simple charge controllers connect photovoltaic modules directly to the battery bank resulting in a significant power loss if the battery bank voltage differs greatly from the PV Maximum Power Point (MPP) voltage. Recent modeling work at AES has shown that dc-dc converter type MPP tracking charge controllers can deliver more than 30% more energy from PV modules to the battery when the PV modules are cool and the battery state of charge is low--this is typically both the worst case condition (i.e., winter) and also the design condition that determines the PV array size. Economic modeling, based on typical telecommore » system installed costs shows benefits of more than $3/Wp for MPPT over conventional charge controllers in this application--a value that greatly exceeds the additional cost of the dc-dc converter.« less

Recovering valuable metals from recycled photovoltaic modules.

PubMed

Yi, Youn Kyu; Kim, Hyun Soo; Tran, Tam; Hong, Sung Kil; Kim, Myong Jun

2014-07-01

Recovering valuable metals such as Si, Ag, Cu, and Al has become a pressing issue as end-of-life photovoltaic modules need to be recycled in the near future to meet legislative requirements in most countries. Of major interest is the recovery and recycling of high-purity silicon (> 99.9%) for the production of wafers and semiconductors. The value of Si in crystalline-type photovoltaic modules is estimated to be -$95/kW at the 2012 metal price. At the current installed capacity of 30 GW/yr, the metal value in the PV modules represents valuable resources that should be recovered in the future. The recycling of end-of-life photovoltaic modules would supply > 88,000 and 207,000 tpa Si by 2040 and 2050, respectively. This represents more than 50% of the required Si for module fabrication. Experimental testwork on crystalline Si modules could recover a > 99.98%-grade Si product by HNO3/NaOH leaching to remove Al, Ag, and Ti and other metal ions from the doped Si. A further pyrometallurgical smelting at 1520 degrees C using CaO-CaF2-SiO2 slag mixture to scavenge the residual metals after acid leaching could finally produce > 99.998%-grade Si. A process based on HNO3/NaOH leaching and subsequent smelting is proposed for recycling Si from rejected or recycled photovoltaic modules. Implications: The photovoltaic industry is considering options of recycling PV modules to recover metals such as Si, Ag, Cu, Al, and others used in the manufacturing of the PV cells. This is to retain its "green" image and to comply with current legislations in several countries. An evaluation of potential resources made available from PV wastes and the technologies used for processing these materials is therefore of significant importance to the industry. Of interest are the costs of processing and the potential revenues gained from recycling, which should determine the viability of economic recycling of PV modules in the future.

A definition study of the on-orbit assembly operations for the outboard photovoltaic power modules for Space Station Freedom. M.S. Thesis - Toledo Univ.

NASA Technical Reports Server (NTRS)

Sours, Thomas J.

1989-01-01

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

Numerical modelling of CIGS/CdS solar cell

NASA Astrophysics Data System (ADS)

Devi, Nisha; Aziz, Anver; Datta, Shouvik

2018-05-01

In this work, we design and analyze the Cu(In,Ga)Se2 (CIGS) solar cell using simulation software "Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D)". The conventional CIGS solar cell uses various layers, like intrinsic ZnO/Aluminium doped ZnO as transparent oxide, antireflection layer MgF2, and electron back reflection (EBR) layer at CIGS/Mo interface for good power conversion efficiency. We replace this conventional model by a simple model which is easy to fabricate and also reduces the cost of this cell because of use of lesser materials. The new designed model of CIGS solar cell is ITO/CIGS/OVC/CdS/Metal contact, where OVC is ordered vacancy compound. From this simple structure, even at very low illumination we are getting good results. We simulate this CIGS solar cell model by varying various physical parameters of CIGS like thickness, carrier density, band gap and temperature.

Reliability and energy efficiency of zero energy homes (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.

2016-09-01

Photovoltaic (PV) modules and systems are being installed increasingly on residential homes to increase the proportion of renewable energy in the energy mix. The ultimate goal is to attain sustainability without subsidy. The prices of PV modules and systems have declined substantially during the recent years. They will be reduced further to reach grid parity. Additionally the total consumed energy must be reduced by making the homes more energy efficient. FSEC/UCF Researchers have carried out research on development of PV cells and systems and on reducing the energy consumption in homes and by small businesses. Additionally, they have provided guidance on PV module and system installation and to make the homes energy efficient. The produced energy is fed into the utility grid and the consumed energy is obtained from the utility grid, thus the grid is assisting in the storage. Currently the State of Florida permits net metering leading to equal charge for the produced and consumed electricity. This paper describes the installation of 5.29 KW crystalline silicon PV system on a south-facing tilt at approximately latitude tilt on a single-story, three-bedroom house. It also describes the computer program on Building Energy Efficiency and the processes that were employed for reducing the energy consumption of the house by improving the insulation, air circulation and windows, etc. Finally it describes actual consumption and production of electricity and the installation of additional crystalline silicon PV modules and balance of system to make it a zero energy home.

Holographic lens spectrum splitting photovoltaic system for increased diffuse collection and annual energy yield

NASA Astrophysics Data System (ADS)

Vorndran, Shelby D.; Wu, Yuechen; Ayala, Silvana; Kostuk, Raymond K.

2015-09-01

Concentrating and spectrum splitting photovoltaic (PV) modules have a limited acceptance angle and thus suffer from optical loss under off-axis illumination. This loss manifests itself as a substantial reduction in energy yield in locations where a significant portion of insulation is diffuse. In this work, a spectrum splitting PV system is designed to efficiently collect and convert light in a range of illumination conditions. The system uses a holographic lens to concentrate shortwavelength light onto a smaller, more expensive indium gallium phosphide (InGaP) PV cell. The high efficiency PV cell near the axis is surrounded with silicon (Si), a less expensive material that collects a broader portion of the solar spectrum. Under direct illumination, the device achieves increased conversion efficiency from spectrum splitting. Under diffuse illumination, the device collects light with efficiency comparable to a flat-panel Si module. Design of the holographic lens is discussed. Optical efficiency and power output of the module under a range of illumination conditions from direct to diffuse are simulated with non-sequential raytracing software. Using direct and diffuse Typical Metrological Year (TMY3) irradiance measurements, annual energy yield of the module is calculated for several installation sites. Energy yield of the spectrum splitting module is compared to that of a full flat-panel Si reference module.

Wafer integrated micro-scale concentrating photovoltaics

NASA Astrophysics Data System (ADS)

Gu, Tian; Li, Duanhui; Li, Lan; Jared, Bradley; Keeler, Gordon; Miller, Bill; Sweatt, William; Paap, Scott; Saavedra, Michael; Das, Ujjwal; Hegedus, Steve; Tauke-Pedretti, Anna; Hu, Juejun

2017-09-01

Recent development of a novel micro-scale PV/CPV technology is presented. The Wafer Integrated Micro-scale PV approach (WPV) seamlessly integrates multijunction micro-cells with a multi-functional silicon platform that provides optical micro-concentration, hybrid photovoltaic, and mechanical micro-assembly. The wafer-embedded micro-concentrating elements is shown to considerably improve the concentration-acceptance-angle product, potentially leading to dramatically reduced module materials and fabrication costs, sufficient angular tolerance for low-cost trackers, and an ultra-compact optical architecture, which makes the WPV module compatible with commercial flat panel infrastructures. The PV/CPV hybrid architecture further allows the collection of both direct and diffuse sunlight, thus extending the geographic and market domains for cost-effective PV system deployment. The WPV approach can potentially benefits from both the high performance of multijunction cells and the low cost of flat plate Si PV systems.

Scheme for predictive fault diagnosis in photo-voltaic modules using thermal imaging

NASA Astrophysics Data System (ADS)

Jaffery, Zainul Abdin; Dubey, Ashwani Kumar; Irshad; Haque, Ahteshamul

2017-06-01

Degradation of PV modules can cause excessive overheating which results in a reduced power output and eventually failure of solar panel. To maintain the long term reliability of solar modules and maximize the power output, faults in modules need to be diagnosed at an early stage. This paper provides a comprehensive algorithm for fault diagnosis in solar modules using infrared thermography. Infrared Thermography (IRT) is a reliable, non-destructive, fast and cost effective technique which is widely used to identify where and how faults occurred in an electrical installation. Infrared images were used for condition monitoring of solar modules and fuzzy logic have been used to incorporate intelligent classification of faults. An automatic approach has been suggested for fault detection, classification and analysis. IR images were acquired using an IR camera. To have an estimation of thermal condition of PV module, the faulty panel images were compared to a healthy PV module thermal image. A fuzzy rule-base was used to classify faults automatically. Maintenance actions have been advised based on type of faults.

Study of 1 MW PV array at the Kennedy Space Center

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.; Schneller, Eric; Martin, Wayne R.; Dhere, Ramesh G.

2016-09-01

FP and L has deployed a 1 MW c-Si in a fenced compound at the Kennedy Space Center. Two 500 kW inverters located in an elevated and air-conditioned enclosure convert direct current (DC) to alternating current (AC). The generated power, DC and AC voltages and currents are measured and recorded. Charts of variation of PV parameters are generated for analyses. The generated power is also tabulated and reported on periodic basis. Infrared and visual images of the array, sections of the array, and of individual modules from the front and back are recorded periodically. Any interruption of power generation are recorded. The dust and corrosion on screws and frame were observed in a few modules. The temperature of active area of module is higher than that of metallic support and frame probably because of conduction of the heat by the heavy metallic structure. The 1-MW PV array is operating normally without signs of excessive degradation except for collection of dust towards the bottom of a few modules. Since these modules were not washed periodically and any cleaning was by rain. Thus the collection of dust towards the bottom of modules can be understood and does not pose a serious problem. Corrosion on screws and frame were observed in a few modules. This study if continued over a long time, will serve to follow the behavior of this reasonable size PV Plant.

Recycling WEEE: Polymer characterization and pyrolysis study for waste of crystalline silicon photovoltaic modules.

PubMed

Dias, Pablo; Javimczik, Selene; Benevit, Mariana; Veit, Hugo

2017-02-01

Photovoltaic (PV) modules contain both valuable and hazardous materials, which makes its recycling meaningful economically and environmentally. In general, the recycling of PV modules starts with the removal of the polymeric ethylene-vinyl acetate (EVA) resin using pyrolysis, which assists in the recovery of materials such as silicon, copper and silver. The pyrolysis implementation, however, needs improvement given its importance. In this study, the polymers in the PV modules were characterized by Fourier transform infrared spectroscopy (FTIR) and the removal of the EVA resin using pyrolysis has been studied and optimized. The results revealed that 30min pyrolysis at 500°C removes >99% of the polymers present in photovoltaic modules. Moreover, the behavior of different particle size milled modules during the pyrolysis process was evaluated. It is shown that polymeric materials tend to remain at a larger particle size and thus, this fraction has the greatest mass loss during pyrolysis. A thermo gravimetric analysis (TGA) performed in all polymeric matter revealed the optimum pyrolysis temperature is around 500°C. Temperatures above 500°C continue to degrade matter, but mass loss rate is 6.25 times smaller. This study demonstrates the use of pyrolysis can remove >99% of the polymeric matter from PV modules, which assists the recycling of this hazardous waste and avoids its disposal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Selenization Processes on CIGS Solar Cell Performance.

PubMed

Wu, C H; Wu, P W; Chen, J H; Kao, J Y; Hsu, C Y

2018-07-01

Cu(In, Ga)Se2 (CIGS) films were fabricated by a two-step process method using sputtering from Cu0.7Ga0.3 and In targets. The metallic precursor structures of In/CuGa/In were prepared, and CuGa film was adjusted to the thicknesses of 150, 200, 250 and 300 nm, in order to optimize the CIGS film. After selenization, three independent CIGS (112), CIGS (220/204) and CIGS (312/116) began to crystallize at ~280 °C and phase peaks continued growing until 560 °C. Experimental results showed that with a single stage selenization method, the excessive stoichiometry of the CIGS films was obtained. Using three sequential stages for the selenization process, with a annealing time of 20 min, the stoichiometry of the CIGS absorbers with the Cu/(In + Ga) and Ga/(In + Ga) showed atomic ratios of 0.94 and 0.34, respectively. The intensity of the (112) XRD diffraction peak became stronger, indicating an improvement in the crystallinity. Raman spectra of CIGS absorbers showed a main peak (174 cm-1) and two weak signals (212 and 231 cm-1). TEM image for electron diffraction pattern showed that the grains were randomly oriented. CIGS solar cell device prepared with a proper selenization, a maximum efficiency of 12.45% was obtained.

Modeling and Simulation of a DG-Integrated Intelligent Microgrid

DTIC Science & Technology

2010-02-01

17. The I-V curve from the manufacturer for BP-4175 175W PV module...........................32   Fig. 18. Wind turbine model...33   Fig. 19. Electrical outputs of wind turbine... PMSG : Permanent Magnet Synchronous Generator PLL : Phase Lock Loop PV : Photovoltaic PWM : Pulse Width Modulation TOU : Time of Use VTES

Solar photovoltaic charging of lithium-ion batteries

NASA Astrophysics Data System (ADS)

Gibson, Thomas L.; Kelly, Nelson A.

Solar photovoltaic (PV) charging of batteries was tested by using high efficiency crystalline and amorphous silicon PV modules to recharge lithium-ion battery modules. This testing was performed as a proof of concept for solar PV charging of batteries for electrically powered vehicles. The iron phosphate type lithium-ion batteries were safely charged to their maximum capacity and the thermal hazards associated with overcharging were avoided by the self-regulating design of the solar charging system. The solar energy to battery charge conversion efficiency reached 14.5%, including a PV system efficiency of nearly 15%, and a battery charging efficiency of approximately 100%. This high system efficiency was achieved by directly charging the battery from the PV system with no intervening electronics, and matching the PV maximum power point voltage to the battery charging voltage at the desired maximum state of charge for the battery. It is envisioned that individual homeowners could charge electric and extended-range electric vehicles from residential, roof-mounted solar arrays, and thus power their daily commuting with clean, renewable solar energy.

Self-anti-reflective density-modulated thin films by HIPS technique

NASA Astrophysics Data System (ADS)

Keles, Filiz; Badradeen, Emad; Karabacak, Tansel

2017-08-01

A critical factor for an efficient light harvesting device is reduced reflectance in order to achieve high optical absorptance. In this regard, refractive index engineering becomes important to minimize reflectance. In this study, a new fabrication approach to obtain density-modulated CuIn x Ga(1-x)Se2 (CIGS) thin films with self-anti-reflective properties has been demonstrated. Density-modulated CIGS samples were fabricated by utilizing high pressure sputtering (HIPS) at Ar gas pressure of 2.75 × 10-2 mbar along with conventional low pressure sputtering (LPS) at Ar gas pressure of 3.0 × 10-3 mbar. LPS produces conventional high density thin films while HIPS produces low density thin films with approximate porosities of ˜15% due to a shadowing effect originating from the wide-spread angular atomic of HIPS. Higher pressure conditions lower the film density, which also leads to lower refractive index values. Density-modulated films that incorporate a HIPS layer at the side from which light enters demonstrate lower reflectance thus higher absorptance compared to conventional LPS films, although there is not any significant morphological difference between them. This result can be attributed to the self-anti-reflective property of the density-modulated samples, which was confirmed by the reduced refractive index calculated for HIPS layer via an envelope method. Therefore, HIPS, a simple and scalable approach, can provide enhanced optical absorptance in thin film materials and eliminate the need for conventional light trapping methods such as anti-reflective coatings of different materials or surface texturing.

Enjoyment and other reasons for electronic cigarette use: Results from college students in New York.

PubMed

Saddleson, M L; Kozlowski, L T; Giovino, G A; Goniewicz, M L; Mahoney, M C; Homish, G G; Arora, A

2016-03-01

Young people are more likely to have experimented with e-cigarettes (e-cigs) compared with older adults. Few studies identify reasons for experimentation/use of e-cigs among young people; we sought to discover what drives college students to use e-cigs. Undergraduate students (ages 18-23) at four universities in New York State were surveyed. Among e-cig ever users (n=429), reasons for use were examined. A multinomial logistic regression model analyzed the relative risk of reasons for using e-cigs among discontinued, current non-daily and current daily e-cig users. Using e-cigs for enjoyment was associated with current non-daily (RR=2.11, 95% CI=1.18-3.75) and current daily use (RR=19.1, 95% CI=3.71-98.54). Non-daily use was related to use because e-cigs are less toxic than cigarettes (RR=2.80, 95% CI=1.75-4.50). More daily users reported use to quit smoking compared with either non-daily or discontinued users (53.3% vs. 12.2% and 13.3%, respectively; p<0.05). Among current users, 72.3% used for enjoyment, compared with 42.9% of discontinued users (p<0.05). In contrast to adults, who often report e-cig use to quit smoking, young people are less likely to use for this reason. The exception was daily e-cig users, who often reported use for quitting/reduction of smoking. Rather, college students report usage reasons related to affect (e.g. enjoyment). Overall, enjoyment was reported more often than was use for quitting smoking; affective reasons likely play a role in the popularity of e-cigs and should be considered in future assessments of e-cig users. Copyright © 2015 Elsevier Ltd. All rights reserved.

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 an equivalent year of testing.

Toward automated e-cigarette surveillance: Spotting e-cigarette proponents on Twitter.

PubMed

Kavuluru, Ramakanth; Sabbir, A K M

2016-06-01

Electronic cigarettes (e-cigarettes or e-cigs) are a popular emerging tobacco product. Because e-cigs do not generate toxic tobacco combustion products that result from smoking regular cigarettes, they are sometimes perceived and promoted as a less harmful alternative to smoking and also as means to quit smoking. However, the safety of e-cigs and their efficacy in supporting smoking cessation is yet to be determined. Importantly, the federal drug administration (FDA) currently does not regulate e-cigs and as such their manufacturing, marketing, and sale is not subject to the rules that apply to traditional cigarettes. A number of manufacturers, advocates, and e-cig users are actively promoting e-cigs on Twitter. We develop a high accuracy supervised predictive model to automatically identify e-cig "proponents" on Twitter and analyze the quantitative variation of their tweeting behavior along popular themes when compared with other Twitter users (or tweeters). Using a dataset of 1000 independently annotated Twitter profiles by two different annotators, we employed a variety of textual features from latest tweet content and tweeter profile biography to build predictive models to automatically identify proponent tweeters. We used a set of manually curated key phrases to analyze e-cig proponent tweets from a corpus of over one million e-cig tweets along well known e-cig themes and compared the results with those generated by regular tweeters. Our model identifies e-cig proponents with 97% precision, 86% recall, 91% F-score, and 96% overall accuracy, with tight 95% confidence intervals. We find that as opposed to regular tweeters that form over 90% of the dataset, e-cig proponents are a much smaller subset but tweet two to five times more than regular tweeters. Proponents also disproportionately (one to two orders of magnitude more) highlight e-cig flavors, their smoke-free and potential harm reduction aspects, and their claimed use in smoking cessation. Given FDA is currently in the process of proposing meaningful regulation, we believe our work demonstrates the strong potential of informatics approaches, specifically machine learning, for automated e-cig surveillance on Twitter. Copyright © 2016 Elsevier Inc. All rights reserved.

2014 NREL Photovoltaic Reliability Workshops | Photovoltaic Research | NREL

Science.gov Websites

Curves and Visual Inspection of PV Modules Deployed at TEP Solar Test Yard-Peter McNutt, NREL Data Determining PV System's Degradation Rate and the Impact of Data Filters-Wilson Zexu Zhang, REC Solar Pte. Ltd " Test in Qualifying Solar PV Inverters-Dutch Uselton, Lennox IND System Reliability for Utility PV

Power Generation Potential and Cost of a Roof Top Solar PV System in Kathmandu, Nepal

NASA Astrophysics Data System (ADS)

Sanjel, N.; Zhand, A.

2017-12-01

The paper presents a comparative study of the 3 most used solar PV module technologies in Nepal, which are Si-mono-crystalline, Si-poly-crystalline and Si-amorphous. The aim of the paper is to present and discuss the recorded Global Solar Radiation, received in the Kathmandu valley by three different, Si-mono-crystalline, Si-poly-crystalline and Si-amorphous calibrated solar cell pyranometers and to propose the best-suited solar PV module technology for roof top solar PV systems inside the Kathmandu valley. Data recorded over the course of seven months, thus covering most of the seasonal meteorological conditions determining Kathmandu valley's global solar radiation reception are presented. The results indicate that the Si-amorphous pyranometer captured 1.56% more global solar radiation than the Si-mono-crystalline and 18.4% more than Si-poly-crystalline pyranometer over the course of seven months. Among the three pyranometer technologies the maximum and minimum cell temperature was measured by the Si-mono-crystalline pyranometer. Following the technical data and discussion, an economical analysis, using the versatile software tool PVSYST V5.01is used to calculate the life cycle costs of a 1kW roof top solar PV RAPS system, with battery storage, and a 1kW roof top solar PV grid connected system with no energy storage facility, through simulations, using average recorded global solar radiation data for the KTM valley and investigated market values for each solar PV module and peripheral equipment costs.

Chapter 10.2: Encapsulant Materials for PV Modules

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

Kempe, Michael D

2017-01-07

Encapsulant materials used in photovoltaic (PV) modules serve multiple purposes; it provides optical coupling of PV cells and protection against environmental stress. Polymers must perform these functions under prolonged periods of high temperature, humidity, and UV radiation. When PV panels were first developed in the 1960s and the 1970s, the dominant encapsulants were based on polydimethyl siloxane (PDMS). Ethylene-co-vinyl acetate (EVA) is currently the dominant encapsulant chosen for PV applications, not because it has the best combination of properties, but because it is an economical option with an established history of acceptable durability. Getting new products onto the market ismore » challenging because there is no room for dramatic improvements, and one must balance the initial cost and performance with the unknowns of long-term service life. Recently, there has been renewed interest in using alternative encapsulant materials with some significant manufacturers switching from EVA to polyolefin elastomer-based (POE) alternatives.« less

Effects of the environment on galaxies in the Catalogue of Isolated Galaxies: physical satellites and large scale structure

NASA Astrophysics Data System (ADS)

Argudo-Fernández, M.; Verley, S.; Bergond, G.; Sulentic, J.; Sabater, J.; Fernández Lorenzo, M.; Espada, D.; Leon, S.; Sánchez-Expósito, S.; Santander-Vela, J. D.; Verdes-Montenegro, L.

2014-04-01

Context. We present a study of the 3D environment for a sample of 386 galaxies in the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973) using the Ninth Data Release of the Sloan Digital Sky Survey (SDSS-DR9). Aims: We aim to identify and quantify the effects of the satellite distribution around a sample of galaxies in the CIG, as well as the effects of the large-scale structure (LSS). Methods: To recover the physically bound galaxies we first focused on the satellites that are within the escape speed of each CIG galaxy. We also propose a more conservative method using the stacked Gaussian distribution of the velocity difference of the neighbours. The tidal strengths affecting the primary galaxy were estimated to quantify the effects of the local and LSS environments. We also defined the projected number density parameter at the fifth nearest neighbour to characterise the LSS around the CIG galaxies. Results: Out of the 386 CIG galaxies considered in this study, at least 340 (88% of the sample) have no physically linked satellite. Following the more conservative Gaussian distribution of physical satellites around the CIG galaxies leads to upper limits. Out of the 386 CIG galaxies, 327 (85% of the sample) have no physical companion within a projected distance of 0.3 Mpc. The CIG galaxies are distributed following the LSS of the local Universe, although presenting a large heterogeneity in their degree of connection with it. When present around a CIG galaxy, the effect of physically bound galaxies largely dominates (typically by more than 90%) the tidal strengths generated by the LSS. Conclusions: The CIG samples a variety of environments, from galaxies with physical satellites to galaxies without neighbours within 3 Mpc. A clear segregation appears between early-type CIG galaxies with companions and isolated late-type CIG galaxies. Isolated galaxies are in general bluer, with probably younger stellar populations and very high star formation compared with older, redder CIG galaxies with companions. Reciprocally, the satellites are redder and with an older stellar populations around massive early-type CIG galaxies, while they have a younger stellar content around massive late-type CIG galaxies. This suggests that the CIG is composed of a heterogeneous population of galaxies, sampling from old to more recent, dynamical systems of galaxies. CIG galaxies with companions might have a mild tendency (0.3-0.4 dex) to be more massive, and may indicate a higher frequency of having suffered a merger in the past. The full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/A94

NREL Research Team Wins R&D 100 Award | News | NREL

Science.gov Websites

performance PV modules for large-scale solar power plants, commercial and residential buildings, and off-grid Laboratory (NREL) and First Solar have been selected to receive a 2003 R&D 100 award from R&D Magazine for developing a new process for depositing semiconductor layers onto photovoltaic (PV) modules

75 FR 65306 - Notice of Intent To Prepare an Environmental Impact Statement for a Proposed Federal Loan...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-22

... installation of about nine million photovoltaic (PV) solar modules within approximately 437 arrays and... final project design. The proposed Project would consist of: A solar field of ground-mounted PV modules... Federal Loan Guarantee To Support Construction of the Topaz Solar Farm, San Luis Obispo County, CA AGENCY...

Assessing the Causes of Encapsulant Delamination in PV Modules

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

Wohlgemuth, John H.; Hacke, Peter; Bosco, Nick

Delamination of the encapsulant is one of the most prevalent PV module field failures. This paper will present examples of various types of delaminations that have been observed in the field. It will then discuss the development of accelerated stress tests designed to duplicate those field failures and thus provide tools for avoiding them in the future.

Module Degradation Mechanisms Studied by a Multi-Scale Approach

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

Johnston, Steve; Al-Jassim, Mowafak; Hacke, Peter

2016-11-21

A key pathway to meeting the Department of Energy SunShot 2020 goals is to reduce financing costs by improving investor confidence through improved photovoltaic (PV) module reliability. A comprehensive approach to further understand and improve PV reliability includes characterization techniques and modeling from module to atomic scale. Imaging techniques, which include photoluminescence, electroluminescence, and lock-in thermography, are used to locate localized defects responsible for module degradation. Small area samples containing such defects are prepared using coring techniques and are then suitable and available for microscopic study and specific defect modeling and analysis.

75 FR 52322 - Nationwide Limited Public Interest Waiver Under Section 1605 (Buy American) of the American...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-25

... ancillary solar Photovoltaic (PV) equipment, when this equipment is utilized in solar installations... following solar PV equipment: (1) Domestically- manufactured modules containing foreign-manufactured cells... effect. Solar cells are the basic building block of PV technologies. The cells are functional...

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...

Resource recovery from urban stock, the example of cadmium and tellurium from thin film module recycling

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

Simon, F.-G., E-mail: franz-georg.simon@bam.de; Holm, O.; Berger, W.

2013-04-15

Highlights: ► The semiconductor layer on thin-film photovoltaic modules can be removed from the glass-plate by vacuum blast cleaning. ► The separation of blasting agent and semiconductor can be performed using flotation with a valuable yield of 55%. ► PV modules are a promising source for the recovery of tellurium in the future. - Abstract: Raw material supply is essential for all industrial activities. The use of secondary raw material gains more importance since ore grade in primary production is decreasing. Meanwhile urban stock contains considerable amounts of various elements. Photovoltaic (PV) generating systems are part of the urban stockmore » and recycling technologies for PV thin film modules with CdTe as semiconductor are needed because cadmium could cause hazardous environmental impact and tellurium is a scarce element where future supply might be constrained. The paper describes a sequence of mechanical processing techniques for end-of-life PV thin film modules consisting of sandblasting and flotation. Separation of the semiconductor material from the glass surface was possible, however, enrichment and yield of valuables in the flotation step were non-satisfying. Nevertheless, recovery of valuable metals from urban stock is a viable method for the extension of the availability of limited natural resources.« less

Scalable fabrication of perovskite solar cells

DOE PAGES

Li, Zhen; Klein, Talysa R.; Kim, Dong Hoe; ...

2018-03-27

Perovskite materials use earth-abundant elements, have low formation energies for deposition and are compatible with roll-to-roll and other high-volume manufacturing techniques. These features make perovskite solar cells (PSCs) suitable for terawatt-scale energy production with low production costs and low capital expenditure. Demonstrations of performance comparable to that of other thin-film photovoltaics (PVs) and improvements in laboratory-scale cell stability have recently made scale up of this PV technology an intense area of research focus. Here, we review recent progress and challenges in scaling up PSCs and related efforts to enable the terawatt-scale manufacturing and deployment of this PV technology. We discussmore » common device and module architectures, scalable deposition methods and progress in the scalable deposition of perovskite and charge-transport layers. We also provide an overview of device and module stability, module-level characterization techniques and techno-economic analyses of perovskite PV modules.« less

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

Li, Zhen; Klein, Talysa R.; Kim, Dong Hoe

Perovskite materials use earth-abundant elements, have low formation energies for deposition and are compatible with roll-to-roll and other high-volume manufacturing techniques. These features make perovskite solar cells (PSCs) suitable for terawatt-scale energy production with low production costs and low capital expenditure. Demonstrations of performance comparable to that of other thin-film photovoltaics (PVs) and improvements in laboratory-scale cell stability have recently made scale up of this PV technology an intense area of research focus. Here, we review recent progress and challenges in scaling up PSCs and related efforts to enable the terawatt-scale manufacturing and deployment of this PV technology. We discussmore » common device and module architectures, scalable deposition methods and progress in the scalable deposition of perovskite and charge-transport layers. We also provide an overview of device and module stability, module-level characterization techniques and techno-economic analyses of perovskite PV modules.« less

Behavioral data of thin-film single junction amorphous silicon (a-Si) photovoltaic modules under outdoor long term exposure

PubMed Central

Kichou, Sofiane; Silvestre, Santiago; Nofuentes, Gustavo; Torres-Ramírez, Miguel; Chouder, Aissa; Guasch, Daniel

2016-01-01

Four years׳ behavioral data of thin-film single junction amorphous silicon (a-Si) photovoltaic (PV) modules installed in a relatively dry and sunny inland site with a Continental-Mediterranean climate (in the city of Jaén, Spain) are presented in this article. The shared data contributes to clarify how the Light Induced Degradation (LID) impacts the output power generated by the PV array, especially in the first days of exposure under outdoor conditions. Furthermore, a valuable methodology is provided in this data article permitting the assessment of the degradation rate and the stabilization period of the PV modules. Further discussions and interpretations concerning the data shared in this article can be found in the research paper “Characterization of degradation and evaluation of model parameters of amorphous silicon photovoltaic modules under outdoor long term exposure” (Kichou et al., 2016) [1]. PMID:26977439

Data acquisition and PV module power production in upgraded TEP/AzRISE solar test yard

NASA Astrophysics Data System (ADS)

Bennett, Whit E.; Fishgold, Asher D.; Lai, Teh; Potter, Barrett G.; Simmons-Potter, Kelly

2017-08-01

The Tucson Electric Power (TEP)/University of Arizona AzRISE (Arizona Research Institute for Solar Energy) solar test yard is continuing efforts to improve standardization and data acquisition reliability throughout the facility. Data reliability is ensured through temperature-insensitive data acquisition devices with battery backups in the upgraded test yard. Software improvements allow for real-time analysis of collected data, while uploading to a web server. Sample data illustrates high fidelity monitoring of the burn-in period of a polycrystalline silicon photovoltaic module test string with no data failures over 365 days of data collection. In addition to improved DAQ systems, precision temperature monitoring has been implemented so that PV module backside temperatures are routinely obtained. Weather station data acquired at the test yard provides local ambient temperature, humidity, wind speed, and irradiance measurements that have been utilized to enable characterization of PV module performance over an extended test period

Space Station Freedom photovoltaic power module design status

NASA Technical Reports Server (NTRS)

Jimenez, Amador P.; Hoberecht, Mark A.

1989-01-01

Electric power generation for the Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during phase I operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units to achieve modularization. The design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

Space Station Freedom photovoltaic power module design status

NASA Technical Reports Server (NTRS)

Jimenez, Amador P.; Hoberecht, Mark A.

1989-01-01

Electric power generation for Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during Phase 1 operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units (ORU's) to achieve modularization. Design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

Advanced Computer Image Generation Techniques Exploiting Perceptual Characteristics. Final Report.

ERIC Educational Resources Information Center

Stenger, Anthony J.; And Others

This study suggests and identifies computer image generation (CIG) algorithms for visual simulation that improve the training effectiveness of CIG simulators and identifies areas of basic research in visual perception that are significant for improving CIG technology. The first phase of the project entailed observing three existing CIG simulators.…

[Effects of cornel iridoid glycoside on activity of cholinesterases in vitro].

PubMed

Chu, Si-Juan; Zhang, Lan; Liu, Gang; Zhou, Wen-Xia; Li, Lin

2013-05-01

The purpose of the present study was to investigate the effects of cornel iridoid glycoside (CIG) on the activity of cholinesterases in vitro, and to investigate the mechanism of CIG's treating Alzheimer's disease (AD). The sources of cholinesterases were prepared from human blood cells, rat brain homogenate and human blood plasma, respectively. The biochemical methods were used to detect the activity of acetylcholine esterase (AChE) and butyryl cholinesterase (BuChE) to investigate the influence of CIG on cholinesterases. The results showed that CIG inhibited the activity of AChE of human blood cells and rat brain homogenate, with the 50% inhibition rate (IC50) of 1.6 g . L-1 and 3.3 g . L-1, respectively; and the inhibition of AChE of CIG is reversible. CIG also inhibited the activity of BuChE of human blood plasma, with the IC50 of 2.9 g . L-1. In conclusion, CIG can inhibit the activity of AChE and BuChE in vitro, which may be one of the mechanisms of CIG to treat AD.

Apparatus and method for mounting photovoltaic power generating systems on buildings

DOEpatents

Russell, Miles Clayton [Lincoln, MA

2008-10-14

Rectangular PV modules (6) are mounted on a building roof (4) by mounting stands that are distributed in rows and columns. Each stand comprises a base plate (10) that rests on the building roof (4) and first and second brackets (12, 14) of different height attached to opposite ends of the base plate (10). Each bracket (12, 14) has dual members for supporting two different PV modules (6), and each PV module (6) has a mounting pin (84) adjacent to each of its four corners. Each module (6) is supported by attachment of two of its mounting pins (84) to different first brackets (12), whereby the modules (6) and their supporting stands are able to resist uplift forces resulting from high velocity winds without the base plates (10) being physically attached to the supporting roof structure (4). Preferably the second brackets (14) have a telescoping construction that permits their effective height to vary from less than to substantially the same as that of the first brackets (12).

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.

Si-Doping Effects in Cu(In,Ga)Se2 Thin Films and Applications for Simplified Structure High-Efficiency Solar Cells.

PubMed

Ishizuka, Shogo; Koida, Takashi; Taguchi, Noboru; Tanaka, Shingo; Fons, Paul; Shibata, Hajime

2017-09-13

We found that elemental Si-doped Cu(In,Ga)Se 2 (CIGS) polycrystalline thin films exhibit a distinctive morphology due to the formation of grain boundary layers several tens of nanometers thick. The use of Si-doped CIGS films as the photoabsorber layer in simplified structure buffer-free solar cell devices is found to be effective in enhancing energy conversion efficiency. The grain boundary layers formed in Si-doped CIGS films are expected to play an important role in passivating CIGS grain interfaces and improving carrier transport. The simplified structure solar cells, which nominally consist of only a CIGS photoabsorber layer and a front transparent and a back metal electrode layer, demonstrate practical application level solar cell efficiencies exceeding 15%. To date, the cell efficiencies demonstrated from this type of device have remained relatively low, with values of about 10%. Also, Si-doped CIGS solar cell devices exhibit similar properties to those of CIGS devices fabricated with post deposition alkali halide treatments such as KF or RbF, techniques known to boost CIGS device performance. The results obtained offer a new approach based on a new concept to control grain boundaries in polycrystalline CIGS and other polycrystalline chalcogenide materials for better device performance.

Limited mutagenicity of electronic cigarettes in mouse or human cells in vitro.

PubMed

Tommasi, Stella; Bates, Steven E; Behar, Rachel Z; Talbot, Prue; Besaratinia, Ahmad

2017-10-01

Electronic cigarettes (e-cig), which are promoted as safe alternatives to tobacco cigarettes or as aides to smoking cessation, are becoming increasingly popular among adult chronic smokers and adolescents experimenting with tobacco products. Despite the known presence of toxicants and carcinogens in e-cig liquid and vapor, the possible carcinogenic effects of e-cig use in humans are unknown. We have utilized two validated in vitro model systems to investigate whether e-cig vapor induces mutation in mouse or human cells. We have exposed transgenic mouse fibroblasts in vitro to e-cig vapor extracts prepared from three popular brands, and determined the induction of mutagenesis in a reporter gene, the cII transgene. Furthermore, we have treated the pSP189 plasmid with e-cig vapor extract, transfected human fibroblast cells with the e-cig-treated plasmid, and screened for the induced mutations in the supF gene. We observed no statistically significant increases in relative mutant frequency in the cII transgene or supF gene in the e-cig treated mouse or human cells, respectively. Our data indicate that e-cig vapor extracts from the selected brands and at concentrations tested in this study have limited mutagenicity in both mouse and human cells in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

The DoE method as an efficient tool for modeling the behavior of monocrystalline Si-PV module

NASA Astrophysics Data System (ADS)

Kessaissia, Fatma Zohra; Zegaoui, Abdallah; Boutoubat, Mohamed; Allouache, Hadj; Aillerie, Michel; Charles, Jean-Pierre

2018-05-01

The objective of this paper is to apply the Design of Experiments (DoE) method to study and to obtain a predictive model of any marketed monocrystalline photovoltaic (mc-PV) module. This technique allows us to have a mathematical model that represents the predicted responses depending upon input factors and experimental data. Therefore, the DoE model for characterization and modeling of mc-PV module behavior can be obtained by just performing a set of experimental trials. The DoE model of the mc-PV panel evaluates the predictive maximum power, as a function of irradiation and temperature in a bounded domain of study for inputs. For the mc-PV panel, the predictive model for both one level and two levels were developed taking into account both influences of the main effect and the interactive effects on the considered factors. The DoE method is then implemented by developing a code under Matlab software. The code allows us to simulate, characterize, and validate the predictive model of the mc-PV panel. The calculated results were compared to the experimental data, errors were estimated, and an accurate validation of the predictive models was evaluated by the surface response. Finally, we conclude that the predictive models reproduce the experimental trials and are defined within a good accuracy.

Effects of nicotine versus placebo e-cigarette use on symptom relief during initial tobacco abstinence.

PubMed

Perkins, Kenneth A; Karelitz, Joshua L; Michael, Valerie C

2017-08-01

Because electronic cigarettes (e-cigs) containing nicotine may relieve smoking abstinence symptoms similar to nicotine replacement therapy medication, we used within-subjects designs to test these effects with a first-generation e-cig in nonquitting and quitting smokers. In Study 1, 28 nontreatment-seeking smokers abstained overnight prior to each of 3 sessions. Minnesota Nicotine Withdrawal Scale (MNWS) withdrawal (and craving item) relief was assessed following 4 exposures (each 10 puffs) over 2 hr to e-cigs that either did (36 mg/ml) or did not (i.e., placebo, 0 mg/ml) contain nicotine or after no e-cig. Relief was greater after nicotine versus placebo e-cig (p < .05) but not after placebo versus no e-cig, showing relief was due to nicotine per se and not simple e-cig use behavior. Using a crossover design in Study 2, smokers preparing to quit soon engaged in 2 experimental 4-day quit periods on separate weeks. In weeks 1 and 3, all received a nicotine or placebo e-cig on Monday to use ad libitum while trying to abstain from smoking on Tuesday through Friday. (Week 2 involved resumption of ad libitum smoking.) MNWS and Questionnaire of Smoking Urges (QSU) craving were assessed at daily visits following 24-hr abstinence. Of 17 enrolled, 12 quit for ≥24 hr at least once, allowing test of relief because of e-cig use on quit days. Withdrawal and craving were reduced because of nicotine versus placebo e-cig use (both p < .05). In sum, compared with placebo e-cigs, nicotine e-cigs can relieve smoking abstinence symptoms, perhaps in a manner similar to Food and Drug Administration-approved nicotine replacement therapy products, although much more research with larger samples is needed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

META-GLARE: A meta-system for defining your own computer interpretable guideline system-Architecture and acquisition.

PubMed

Bottrighi, Alessio; Terenziani, Paolo

2016-09-01

Several different computer-assisted management systems of computer interpretable guidelines (CIGs) have been developed by the Artificial Intelligence in Medicine community. Each CIG system is characterized by a specific formalism to represent CIGs, and usually provides a manager to acquire, consult and execute them. Though there are several commonalities between most formalisms in the literature, each formalism has its own peculiarities. The goal of our work is to provide a flexible support to the extension or definition of CIGs formalisms, and of their acquisition and execution engines. Instead of defining "yet another CIG formalism and its manager", we propose META-GLARE (META Guideline Acquisition, Representation, and Execution), a "meta"-system to define new CIG systems. In this paper, META-GLARE, a meta-system to define new CIG systems, is presented. We try to capture the commonalities among current CIG approaches, by providing (i) a general manager for the acquisition, consultation and execution of hierarchical graphs (representing the control flow of actions in CIGs), parameterized over the types of nodes and of arcs constituting it, and (ii) a library of different elementary components of guidelines nodes (actions) and arcs, in which each type definition involves the specification of how objects of this type can be acquired, consulted and executed. We provide generality and flexibility, by allowing free aggregations of such elementary components to define new primitive node and arc types. We have drawn several experiments, in which we have used META-GLARE to build a CIG system (Experiment 1 in Section 8), or to extend it (Experiments 2 and 3). Such experiments show that META-GLARE provides a useful and easy-to-use support to such tasks. For instance, re-building the Guideline Acquisition, Representation, and Execution (GLARE) system using META-GLARE required less than one day (Experiment 1). META-GLARE is a meta-system for CIGs supporting fast prototyping. Since META-GLARE provides acquisition and execution engines that are parametric over the specific CIG formalism, it supports easy update and construction of CIG systems. Copyright © 2016 Elsevier B.V. All rights reserved.

City and County Solar PV Training Program, Module 1: Goal Setting and Clarification

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

McLaren, Joyce A.

This module will help attendees understand nuances between different types of renewable energy goals, the importance of terminology when setting and announcing goals, the value of formally clarifying priorities, and how priorities may impact procurement options. It is the first training in a series intended to help municipal staff procure solar PV for their land and buildings.

Innovation in Photovoltaic Science, Engineering, and Policy: A Potential Trillion-Dollar Global Industry for Sustainable Energy

NASA Astrophysics Data System (ADS)

Zheng, Cheng

The solar photovoltaic (PV) technology was an expensive niche energy source only for satellite applications, hallmarked by the Bell Lab's launch of the Telstar satellite with PV cells in 1962. Over the past decades, the accumulation of vast amount of effort across various disciplines in science, engineering, and policy has enabled the phenomenal growth of the solar PV industry into a global enterprise with about 140 gigawatt (GW) of cumulative installations by the end of 2013. Further cost reduction through innovation holds the promise in deploying terawatt (TW)-scale solar PV systems globally in both developed and developing countries, meeting growing energy demand and mitigating climate change. Chapter 1 presents a big picture view of the unsustainable path, heavily relying on fossil fuels, in the current global energy landscape. The main body of the dissertation examines the solar PV technology from a holistic and interdisciplinary perspective: from the basic research, to innovations in manufacturing and installing PV modules, to the driving energy policies. Chapter 2 offers a fundamental understanding of the PV technology and a review on recent scientific advances in improving PV efficiency (W/m 2). Chapter 3 reviews the state-of-the-art process flow in manufacturing commercial PV modules. In the context of pursuing further reduction in manufacturing cost (/m2), the thin Si film concept and its recent research effort are reviewed. Aiming to explore novel ways to produce high-quality seed crystals for thin Si film deposition, the key findings of the laser crystallization experiment is presented in Chapter 4. The fundamental thermophysics of nucleation and crystal growth is first reviewed, which highlights the importance of temperature evolution and heat transport in modelling the ultrafast laser crystallization process. Laser crystallization of a range of Si nanostructures are then carried out to study the nucleation and crystal growth behavior under some novel conditions, such as suspended narrow Si membranes and Si nanoparticles confined on top of oxide nanostructures. The cost of a PV module (/W) is determined by both its rated efficiency (W/m2) and its manufacturing cost (/m2). However, the same PV module with the same cost can lead to significantly different levelized cost of electricity (LCOE) in /kWh, depending on the location and configuration of the installed PV system. Chapter 5 starts with an overview of the geographic distribution of solar resources and retail electricity rates, which yield a range of grid parity points across the world. Then, energy yield simulations for different PV panel tilt configurations are carried out using the angle-and-wavelength-resolved solar irradiance data, to examine the effect of angular and spectral variations in the solar spectrum on system performance. Energy policies have been the driving forces for the phenomenal progress of the PV technology: the continuing reduction in cost and the rapid growth in deployment. Chapter 6 first reviews major policy instruments for PV, and then discusses about a few important policy lessons from the rapid development of the global PV industry during 2000-2013. Concerned with the mounting fiscal pressure from deployment incentives and focused on further cost reductions, an innovation-focused policy framework is proposed to revive the PV manufacturing sector and to pursue an innovation-driven global PV industry moving forward.

Solar concentrator modules with silicone-onglass Fresnel lens panels and multijunction cells.

PubMed

Rumyantsev, Valery D

2010-04-26

High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

Solar Electric System

NASA Technical Reports Server (NTRS)

1987-01-01

Heat Pipe Technology, Inc. undertook the development of a PV system that could bring solar electricity to the individual home at reasonable cost. His system employs high efficiency PV modules plus a set of polished reflectors that concentrate the solar energy and enhance the output of the modules. Dinh incorporated a sun tracking system derived from space tracking technology. It automatically follows the sun throughout the day and turns the modules so that they get maximum exposure to the solar radiation, further enhancing the system efficiency.

Outdoor Test Facility and Related Facilities | Photovoltaic Research | NREL

Science.gov Websites

advanced or emerging photovoltaic (PV) technologies under simulated, accelerated indoor and outdoor, and evaluate prototype, pre-commercial, and commercial PV modules. One of the major roles of researchers at the OTF is to work with industry to develop uniform and consensus standards and codes for testing PV

Evaluation of the PV energy production after 12-years of operating

NASA Astrophysics Data System (ADS)

Bouchakour, Salim; Arab, Amar Hadj; Abdeladim, Kamel; Boulahchiche, Saliha; Amrouche, Said Ould; Razagui, Abdelhak

2018-05-01

This paper presents a simple way to approximately evaluate the photovoltaic (PV) array performance degradation, the studied PV arrays are connected to the local electric grid at the Centre de Developpement des Energies Renouvelables (CDER) in Algiers, Algeria, since June 2004. The used PV module model takes in consideration the module temperature and the effective solar radiance, the electrical characteristics provided by the manufacturer data sheet and the evaluation of the performance coefficient. For the dynamic behavior we use the Linear Reoriented Coordinates Method (LRCM) to estimate the maximum power point (MPP). The performance coefficient is evaluated on the one hand under STC conditions to estimate the dc energy according to the manufacturer data. On the other hand, under real conditions using both the monitored data and the LM optimization algorithm, allowing a good degree of accuracy of estimated dc energy. The application of the developed modeling procedure to the analysis of the monitored data is expected to improve understanding and assessment of the PV performance degradation of the PV arrays after 12 years of operation.

State - Level Regulation's Effectiveness in Addressing Global Climate Change and Promoting Solar Energy Deployment

NASA Astrophysics Data System (ADS)

Peterman, Carla Joy

Paper 1, Local Solutions to Global Problems: Climate Change Policies and Regulatory Jurisdiction, considers the efficacy of various types of environmental regulations when they are applied locally to pollutants whose damages extend beyond the jurisdiction of the local regulators. Local regulations of a global pollutant may be ineffective if producers and consumers can avoid them by transacting outside the reach of the local regulator. In many cases, this may involve the physical relocation of the economic activity, a problem often referred to as "leakage." This paper highlights another way in which local policies can be circumvented: through the shuffling of who buys from whom. The paper maintains that the problems of reshuffling are exacerbated when the options for compliance with the regulations are more flexible. Numerical analyses is presented demonstrating that several proposed policies to limit greenhouse gas emissions from the California electricity sector may have very little effect on carbon emissions if they are applied only within that state. Paper 1 concludes that although local subsidies for energy efficiency, renewable electricity, and transportation biofuels constitute attempts to pick technology winners, they may be the only mechanisms that local jurisdictions, acting alone, have at their disposal to address climate change. Paper 2, Pass-Through of Solar PV Incentives to Consumers: The Early Years of California's Solar PV Incentives, examines the pass through of incentives to California solar PV system owners. The full post-subsidy price consumers pay for solar power is a key metric of the success of solar PV incentive programs and of overall PV market performance. This study examines the early years of California's most recent wave of distributed solar PV incentives (2000-2008) to determine the pass-through of incentives. Examination of this period is both intellectually and pragmatically important due to the high level of incentives provided and subsequent high cost to ratepayers; policymakers' expectations that price declines accrue to consumers; and market structure characteristics that might contribute to incomplete pass-through. This analysis shows that incentive passthrough in the California residential solar PV programs was incomplete. Consumer prices declined 54 cents for every additional dollar of incentive received. A large share of the incentive is captured by the solar PV contractor or other actors in the solar PV supply chain. The finding of incomplete pass-through is persistent across specifications. The analysis also identifies a lower degree of incentive pass-through for consumers in the highest income zip codes. Whether expectations of incentives' pass-through align with reality is critically important in the beginning years of emerging clean energy technology programs since this can affect the likelihood of future government investments and public support. Given the often-held policy assumption that consumer prices are declining in response to incentives, it is useful for policymakers to understand the circumstances under which such an assumption may not hold. Paper 3, Testing the Boundaries of the Solar Photovoltaic Learning System, tests how the choice of experience curves' geographic and technology assumptions affect solar PV experience curve results. Historically, solar PV experience curves have assumed one experience curve represents both module and non-module learning and that this learning happens at a global scale. These assumptions may be inaccurate for solar PV since the learning system, and technology and geographic boundaries, are likely different between PV modules and non-module components. Using 2004 to 2008 PV system price data from 13 states, and a longer time series of PV price data for California, some evidence is found that cumulative capacity at the state level is a better predictor of non-module costs than U.S. or global capacity. This paper explores, but is unable to significantly determine, how knowledge spillovers from neighboring states can influence a state's non-module costs. Given data limitations, and limitations to the two-factor experience model methodology itself, it is not possible to conclusively determine the correct geographic boundary for the non-module learning system. Throughout the paper ways in which the experience curve model and data can be augmented to achieve a better estimation are discussed. 2.

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

Wohlgemuth, J.

Description and history of the IEC 61215 qualification test, what it accomplishes, and what it does not accomplish that would be useful to the community. The commercial success of PV is based on long term reliability of the PV modules. Today's modules are typically qualified/certified to: (1) IEC 61215 for Crystalline Silicon Modules; (2) IEC 61646 for Thin Film Modules; and (3) IEC 62108 for CPV Modules. These qualification tests do an excellent job of identifying design, materials and process flaws that could lead to premature field failures. This talk will provide a summary of how IEC 61215 was developed,more » how well it works and what its limitations are.« less

Synchrotron X-Ray Topography for Encapsulation Stress/Strain and Crack Detection in Crystalline Silicon Modules

DOE PAGES

Colli, Alessandra; Attenkofer, Klaus; Raghothamachar, Balaji; ...

2016-07-14

Here in this article, we present the first experiment to prove the capabilities of X-ray topography for the direct imaging and analysis of defects, stress, and strain affecting the cell within the laminated photovoltaic (PV) module. Cracks originating from grain boundaries structures have been detected, developing along the cleavage planes of the crystal. The strain affecting the cell is clearly visualized through the bending of the metallization line images and can be easily mapped. While the recording conditions need to be optimized to maximize image contrast, this experiment demonstrates how synchrotron facilities can enable PV industry and research to characterizemore » full PV modules. Appropriate development of the technique could also lead to future use of laboratory-level X-ray sources.« less

NREL at 40: It All Started With a Desire to Harness the Sun | News | NREL

Science.gov Websites

(PV) industry. Their job was to ultimately develop new solar technology and to chart a path toward its of reliability for PV modules and systems, helping bolster consumer and investor confidence in solar With a Desire to Harness the Sun July 5, 2017 Photo of PV panels under a bright blue sky. A PV array on

Photovoltaics Innovation Roadmap Request for Information Summary

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

None, None

On June 28, 2017, the U.S. Department of Energy’s Solar Energy Technologies Office (SETO) released the Photovoltaics (PV) Innovation Roadmap Request for Information (RFI) for public response and comment. The RFI sought feedback from PV stakeholders, including research and commercial communities, about the most important research and development (R&D) pathways to improve PV cell and module technology to reach the SETO’s SunShot 2030 cost targets of $0.03/W for utility PV installations, $0.04/W for commercial scale installations, and $0.05/W for residential PV installations.

Integrating DC/DC Conversion with Possible Reconfiguration within Submodule Solar Photovoltaic Systems

NASA Astrophysics Data System (ADS)

Huang, Peter Jen-Hung

This research first proposes a method to merge photovoltaic (PV) cells or PV panels within the internal components DC-DC converters. The purpose of this merged structure is to reconfigure the PV modules between series and parallel connections using high switching frequencies (hundreds of kHz). This leads to multi-levels of voltages and currents that become applied to the output filter of the converter. Further, this research introduces a concept of a switching cell that utilizes the reconfiguration of series and parallel connections in DC-DC converters. The switching occurs at high switching frequency and the switches can be integrated to be within the solar panels or in between the solar cells. The concept is generalized and applied to basic buck and boost topologies. As examples of the new types of converters: reconfigurable PV-buck and PV-boost converter topologies are presented. It is also possible to create other reconfigurable power converters: non-isolated and isolated topologies. Analysis, simulation and experimental verification for the reconfigurable PV-buck and PV-boost converters are presented extensively to illustrate proof of concept. Benefits and drawbacks of the new approach are discussed. The second part of this research proposes to utilize the internal solar cell capacitance and internal solar module wire parasitic inductances to replace the input capacitor and filter inductor in boost derived DC-DC converters for energy harvesting applications. High switching frequency (MHz) hard switched and resonant boost converters are proposed. Their analysis, simulation and experimental prototypes are presented. A specific proof-of-concept application is especially tested for foldable PV panels, which are known for their high internal wire inductance. The experimental converters successfully boost solar module voltage without adding any external input capacitance or filter inductor. Benefits and drawbacks of new proposed PV submodule integrated boost converters are discussed.

Capital intensity of photovoltaics manufacturing: Barrier to scale and opportunity for innovation

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

Powell, Douglas M.; Fu, Ran; Horowitz, Kelsey

In this study, using a bottom-up cost model, we assess the impact of initial factory capital expenditure (capex) on photovoltaic (PV) module minimum sustainable price (MSP) and industry-wide trends. We find capex to have two important impacts on PV manufacturing. First, capex strongly influences the per-unit MSP of a c-Si module: we calculate that the capex-related elements sum to 22% of MSP for an integrated wafer, cell, and module manufacturer. This fraction provides a significant opportunity to reduce MSP toward the U.S. DOE SunShot module price target through capex innovation.

Capital intensity of photovoltaics manufacturing: Barrier to scale and opportunity for innovation

DOE PAGES

Powell, Douglas M.; Fu, Ran; Horowitz, Kelsey; ...

2015-09-07

In this study, using a bottom-up cost model, we assess the impact of initial factory capital expenditure (capex) on photovoltaic (PV) module minimum sustainable price (MSP) and industry-wide trends. We find capex to have two important impacts on PV manufacturing. First, capex strongly influences the per-unit MSP of a c-Si module: we calculate that the capex-related elements sum to 22% of MSP for an integrated wafer, cell, and module manufacturer. This fraction provides a significant opportunity to reduce MSP toward the U.S. DOE SunShot module price target through capex innovation.

Will chronic e-cigarette use cause lung disease?

PubMed

Rowell, Temperance R; Tarran, Robert

2015-12-15

Chronic tobacco smoking is a major cause of preventable morbidity and mortality worldwide. In the lung, tobacco smoking increases the risk of lung cancer, and also causes chronic obstructive pulmonary disease (COPD), which encompasses both emphysema and chronic bronchitis. E-cigarettes (E-Cigs), or electronic nicotine delivery systems, were developed over a decade ago and are designed to deliver nicotine without combusting tobacco. Although tobacco smoking has declined since the 1950s, E-Cig usage has increased, attracting both former tobacco smokers and never smokers. E-Cig liquids (e-liquids) contain nicotine in a glycerol/propylene glycol vehicle with flavorings, which are vaporized and inhaled. To date, neither E-Cig devices, nor e-liquids, are regulated by the Food and Drug Administration (FDA). The FDA has proposed a deeming rule, which aims to initiate legislation to regulate E-Cigs, but the timeline to take effect is uncertain. Proponents of E-Cigs say that they are safe and should not be regulated. Opposition is varied, with some opponents proposing that E-Cig usage will introduce a new generation to nicotine addiction, reversing the decline seen with tobacco smoking, or that E-Cigs generally may not be safe and will trigger diseases like tobacco. In this review, we shall discuss what is known about the effects of E-Cigs on the mammalian lung and isolated lung cells in vitro. We hope that collating this data will help illustrate gaps in the knowledge of this burgeoning field, directing researchers toward answering whether or not E-Cigs are capable of causing disease. Copyright © 2015 the American Physiological Society.

Will chronic e-cigarette use cause lung disease?

PubMed Central

Rowell, Temperance R.

2015-01-01

Chronic tobacco smoking is a major cause of preventable morbidity and mortality worldwide. In the lung, tobacco smoking increases the risk of lung cancer, and also causes chronic obstructive pulmonary disease (COPD), which encompasses both emphysema and chronic bronchitis. E-cigarettes (E-Cigs), or electronic nicotine delivery systems, were developed over a decade ago and are designed to deliver nicotine without combusting tobacco. Although tobacco smoking has declined since the 1950s, E-Cig usage has increased, attracting both former tobacco smokers and never smokers. E-Cig liquids (e-liquids) contain nicotine in a glycerol/propylene glycol vehicle with flavorings, which are vaporized and inhaled. To date, neither E-Cig devices, nor e-liquids, are regulated by the Food and Drug Administration (FDA). The FDA has proposed a deeming rule, which aims to initiate legislation to regulate E-Cigs, but the timeline to take effect is uncertain. Proponents of E-Cigs say that they are safe and should not be regulated. Opposition is varied, with some opponents proposing that E-Cig usage will introduce a new generation to nicotine addiction, reversing the decline seen with tobacco smoking, or that E-Cigs generally may not be safe and will trigger diseases like tobacco. In this review, we shall discuss what is known about the effects of E-Cigs on the mammalian lung and isolated lung cells in vitro. We hope that collating this data will help illustrate gaps in the knowledge of this burgeoning field, directing researchers toward answering whether or not E-Cigs are capable of causing disease. PMID:26408554

A study on the optics of copper indium gallium (di)selenide (CIGS) solar cells with ultra-thin absorber layers.

PubMed

Xu, Man; Wachters, Arthur J H; van Deelen, Joop; Mourad, Maurice C D; Buskens, Pascal J P

2014-03-10

We present a systematic study of the effect of variation of the zinc oxide (ZnO) and copper indium gallium (di)selenide (CIGS) layer thickness on the absorption characteristics of CIGS solar cells using a simulation program based on finite element method (FEM). We show that the absorption in the CIGS layer does not decrease monotonically with its layer thickness due to interference effects. Ergo, high precision is required in the CIGS production process, especially when using ultra-thin absorber layers, to accurately realize the required thickness of the ZnO, cadmium sulfide (CdS) and CIGS layer. We show that patterning the ZnO window layer can strongly suppress these interference effects allowing a higher tolerance in the production process.

Technology advances needed for photovoltaics to achieve widespread grid price parity: Widespread grid price parity for photovoltaics

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

Jones-Albertus, Rebecca; Feldman, David; Fu, Ran

2016-04-20

To quantify the potential value of technological advances to the photovoltaics (PV) sector, this paper examines the impact of changes to key PV module and system parameters on the levelized cost of energy (LCOE). The parameters selected include module manufacturing cost, efficiency, degradation rate, and service lifetime. NREL's System Advisor Model (SAM) is used to calculate the lifecycle cost per kilowatt-hour (kWh) for residential, commercial, and utility scale PV systems within the contiguous United States, with a focus on utility scale. Different technological pathways are illustrated that may achieve the Department of Energy's SunShot goal of PV electricity that ismore » at grid price parity with conventional electricity sources. In addition, the impacts on the 2015 baseline LCOE due to changes to each parameter are shown. These results may be used to identify research directions with the greatest potential to impact the cost of PV electricity.« less

Abnormal excessive per vagina (PV) bleeding on Esmya–selective progesterone receptor modulator (SPRM) in a symptomatic patient with uterine fibroid

PubMed Central

Matytsina-Quinlan, Lyubov; Matytsina, Laura

2015-01-01

A woman in her late 40s presented with excessive per vagina (PV) bleeding and uterine fibroid. She reported excessive PV bleeding after starting Esmya; she was brought in by ambulance to the emergency department with profuse bleeding. Abnormal uterine bleeding (AUB) developed after selective progesterone receptor modulator (SPRM) administration in this symptomatic patient with uterine fibroid. The drug was withheld and surgical treatment considered. Progressive deterioration of PV bleeding after receiving SPRM led to an urgent laparoscopic total hysterectomy, which had to be postponed due to severe anaemia. Surgery took place regardless because the excessive bleeding continued. Histology revealed a 6 cm submucosal uterine fibroid (SMUF) and adenomyosis. Physicians prescribing SPRMs to stop PV bleeding should be aware of potential AUB, which could lead to urgent hysterectomy. The mechanism of action of SPRMs is not clearly understood. Awareness of the side effects of Esmya, such as AUB, must be kept in mind when administering SPRMs. PMID:25976198

Abnormal excessive per vagina (PV) bleeding on Esmya-selective progesterone receptor modulator (SPRM) in a symptomatic patient with uterine fibroid.

PubMed

Matytsina-Quinlan, Lyubov; Matytsina, Laura

2015-05-14

A woman in her late 40s presented with excessive per vagina (PV) bleeding and uterine fibroid. She reported excessive PV bleeding after starting Esmya; she was brought in by ambulance to the emergency department with profuse bleeding. Abnormal uterine bleeding (AUB) developed after selective progesterone receptor modulator (SPRM) administration in this symptomatic patient with uterine fibroid. The drug was withheld and surgical treatment considered. Progressive deterioration of PV bleeding after receiving SPRM led to an urgent laparoscopic total hysterectomy, which had to be postponed due to severe anaemia. Surgery took place regardless because the excessive bleeding continued. Histology revealed a 6 cm submucosal uterine fibroid (SMUF) and adenomyosis. Physicians prescribing SPRMs to stop PV bleeding should be aware of potential AUB, which could lead to urgent hysterectomy. The mechanism of action of SPRMs is not clearly understood. Awareness of the side effects of Esmya, such as AUB, must be kept in mind when administering SPRMs. 2015 BMJ Publishing Group Ltd.

On the Path to SunShot - Emerging Opportunities and Challenges in U.S. Solar Manufacturing

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

Chung, Donald; Horowitz, Kelsey; Kurup, Parthiv

Innovation-driven cost and performance improvements, along with strong projected solar demand in the United States and across the Americas, could increase the attractiveness of U.S.-based solar manufacturing (see Chung et al. 2016). Although improvements to standard PV modules have produced deep cost reductions over the past 5 years, the returns on such incremental improvements appear to be diminishing, and more dramatic innovations in module design and manufacturing are required to continue along the path of rapid progress. At the same time, major opportunities exist for innovation to unlock the potential of CSP technologies. This need for innovation could benefit U.S.more » PV and CSP manufacturers. The United States has been rated one of the world’s most competitive and innovative countries as well as one of the best locations for PV manufacturing. It is a global leader in PV and CSP R&D and patent production, and U.S. PV manufacturers are already pursuing highly differentiated innovations.« less

Crystal growth and materials research in photovoltaics: progress and challenges

NASA Astrophysics Data System (ADS)

Surek, Thomas

2005-02-01

Photovoltaics (PV) is solar electric power—a semiconductor-based technology that converts sunlight to electricity. Three decades of research has led to the discovery of new materials and devices and new processing techniques for low-cost manufacturing. This has resulted in improved sunlight-to-electricity conversion efficiencies, improved outdoor reliability, and lower module and system costs. The manufacture and sale of PV has grown into a $5 billion industry worldwide, with more than 740 megawatts of PV modules shipped in 2003. This paper reviews the significant progress that has occurred in PV materials and devices research over the past 30 years, focusing on the advances in crystal growth and materials research, and examines the challenges to reaching the ultimate potential of current-generation (crystalline silicon), next-generation (thin films and concentrators), and future-generation PV technologies. The latter includes innovative materials and device concepts that hold the promise of significantly higher conversion efficiencies and/or much lower costs.

Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation

PubMed Central

Lee, Kyu-Tae; Yao, Yuan; He, Junwen; Fisher, Brent; Sheng, Xing; Lumb, Matthew; Xu, Lu; Anderson, Mikayla A.; Scheiman, David; Han, Seungyong; Kang, Yongseon; Gumus, Abdurrahman; Bahabry, Rabab R.; Lee, Jung Woo; Paik, Ungyu; Bronstein, Noah D.; Alivisatos, A. Paul; Meitl, Matthew; Burroughs, Scott; Hussain, Muhammad Mustafa; Lee, Jeong Chul; Nuzzo, Ralph G.; Rogers, John A.

2016-01-01

Emerging classes of concentrator photovoltaic (CPV) modules reach efficiencies that are far greater than those of even the highest performance flat-plate PV technologies, with architectures that have the potential to provide the lowest cost of energy in locations with high direct normal irradiance (DNI). A disadvantage is their inability to effectively use diffuse sunlight, thereby constraining widespread geographic deployment and limiting performance even under the most favorable DNI conditions. This study introduces a module design that integrates capabilities in flat-plate PV directly with the most sophisticated CPV technologies, for capture of both direct and diffuse sunlight, thereby achieving efficiency in PV conversion of the global solar radiation. Specific examples of this scheme exploit commodity silicon (Si) cells integrated with two different CPV module designs, where they capture light that is not efficiently directed by the concentrator optics onto large-scale arrays of miniature multijunction (MJ) solar cells that use advanced III–V semiconductor technologies. In this CPV+ scheme (“+” denotes the addition of diffuse collector), the Si and MJ cells operate independently on indirect and direct solar radiation, respectively. On-sun experimental studies of CPV+ modules at latitudes of 35.9886° N (Durham, NC), 40.1125° N (Bondville, IL), and 38.9072° N (Washington, DC) show improvements in absolute module efficiencies of between 1.02% and 8.45% over values obtained using otherwise similar CPV modules, depending on weather conditions. These concepts have the potential to expand the geographic reach and improve the cost-effectiveness of the highest efficiency forms of PV power generation. PMID:27930331

Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation

NASA Astrophysics Data System (ADS)

Lee, Kyu-Tae; Yao, Yuan; He, Junwen; Fisher, Brent; Sheng, Xing; Lumb, Matthew; Xu, Lu; Anderson, Mikayla A.; Scheiman, David; Han, Seungyong; Kang, Yongseon; Gumus, Abdurrahman; Bahabry, Rabab R.; Lee, Jung Woo; Paik, Ungyu; Bronstein, Noah D.; Alivisatos, A. Paul; Meitl, Matthew; Burroughs, Scott; Mustafa Hussain, Muhammad; Lee, Jeong Chul; Nuzzo, Ralph G.; Rogers, John A.

2016-12-01

Emerging classes of concentrator photovoltaic (CPV) modules reach efficiencies that are far greater than those of even the highest performance flat-plate PV technologies, with architectures that have the potential to provide the lowest cost of energy in locations with high direct normal irradiance (DNI). A disadvantage is their inability to effectively use diffuse sunlight, thereby constraining widespread geographic deployment and limiting performance even under the most favorable DNI conditions. This study introduces a module design that integrates capabilities in flat-plate PV directly with the most sophisticated CPV technologies, for capture of both direct and diffuse sunlight, thereby achieving efficiency in PV conversion of the global solar radiation. Specific examples of this scheme exploit commodity silicon (Si) cells integrated with two different CPV module designs, where they capture light that is not efficiently directed by the concentrator optics onto large-scale arrays of miniature multijunction (MJ) solar cells that use advanced III-V semiconductor technologies. In this CPV+ scheme (“+” denotes the addition of diffuse collector), the Si and MJ cells operate independently on indirect and direct solar radiation, respectively. On-sun experimental studies of CPV+ modules at latitudes of 35.9886° N (Durham, NC), 40.1125° N (Bondville, IL), and 38.9072° N (Washington, DC) show improvements in absolute module efficiencies of between 1.02% and 8.45% over values obtained using otherwise similar CPV modules, depending on weather conditions. These concepts have the potential to expand the geographic reach and improve the cost-effectiveness of the highest efficiency forms of PV power generation.

Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation.

PubMed

Lee, Kyu-Tae; Yao, Yuan; He, Junwen; Fisher, Brent; Sheng, Xing; Lumb, Matthew; Xu, Lu; Anderson, Mikayla A; Scheiman, David; Han, Seungyong; Kang, Yongseon; Gumus, Abdurrahman; Bahabry, Rabab R; Lee, Jung Woo; Paik, Ungyu; Bronstein, Noah D; Alivisatos, A Paul; Meitl, Matthew; Burroughs, Scott; Hussain, Muhammad Mustafa; Lee, Jeong Chul; Nuzzo, Ralph G; Rogers, John A

2016-12-20

Emerging classes of concentrator photovoltaic (CPV) modules reach efficiencies that are far greater than those of even the highest performance flat-plate PV technologies, with architectures that have the potential to provide the lowest cost of energy in locations with high direct normal irradiance (DNI). A disadvantage is their inability to effectively use diffuse sunlight, thereby constraining widespread geographic deployment and limiting performance even under the most favorable DNI conditions. This study introduces a module design that integrates capabilities in flat-plate PV directly with the most sophisticated CPV technologies, for capture of both direct and diffuse sunlight, thereby achieving efficiency in PV conversion of the global solar radiation. Specific examples of this scheme exploit commodity silicon (Si) cells integrated with two different CPV module designs, where they capture light that is not efficiently directed by the concentrator optics onto large-scale arrays of miniature multijunction (MJ) solar cells that use advanced III-V semiconductor technologies. In this CPV + scheme ("+" denotes the addition of diffuse collector), the Si and MJ cells operate independently on indirect and direct solar radiation, respectively. On-sun experimental studies of CPV + modules at latitudes of 35.9886° N (Durham, NC), 40.1125° N (Bondville, IL), and 38.9072° N (Washington, DC) show improvements in absolute module efficiencies of between 1.02% and 8.45% over values obtained using otherwise similar CPV modules, depending on weather conditions. These concepts have the potential to expand the geographic reach and improve the cost-effectiveness of the highest efficiency forms of PV power generation.

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

Design of A Grid Integrated PV System with MPPT Control and Voltage Oriented Controller using MATLAB/PLECES

NASA Astrophysics Data System (ADS)

Soreng, Bineeta; Behera, Pradyumna; Pradhan, Raseswari

2017-08-01

This paper presents model of a grid-integrated photovoltaic array with Maximum Power Point Tracker (MPPT) and voltage oriented controller. The MPPT of the PV array is usually an essential part of PV system as MPPT helps the operating point of the solar array to align its maximum power point. In this model, the MPPT along with a DC-DC converter lets a PV generator to produce continuous power, despite of the measurement conditions. The neutral-point-clamped converter (NPC) with a boost converter raises the voltage from the panels to the DC-link. An LCL-filter smoothens the current ripple caused by the PWM modulation of the grid-side inverter. In addition to the MPPT, the system has two more two controllers, such as voltage controller and a current controller. The voltage control has a PI controller to regulate the PV voltage to optimal level by controlling the amount of current injected into the boost stage. Here, the grid-side converter transfers the power from the DC-link into the grid and maintains the DC-link voltage. Three-phase PV inverters are used for off-grid or designed to create utility frequency AC. The PV system can be connected in series or parallel to get the desired output power. To justify the working of this model, the grid-integrated PV system has been designed in MATLAB/PLECS. The simulation shows the P-V curve of implemented PV Array consisting 4 X 20 modules, reactive, real power, grid voltage and current.

Gelsolin: a novel thyroid hormone receptor-beta interacting protein that modulates tumor progression in a mouse model of follicular thyroid cancer.

PubMed

Kim, Caroline S; Furuya, Fumihiko; Ying, Hao; Kato, Yasuhito; Hanover, John A; Cheng, Sheue-yann

2007-03-01

Follicular thyroid cancer (FTC) is known to metastasize to distant sites via hematogenous spread; however, the underlying pathways that contribute to metastasis remain unknown. Recent creation of a knockin mutant mouse that expresses a mutant thyroid hormone receptor-beta (TRbeta(PV/PV) mouse) that spontaneously develops thyroid cancer with metastasis similar to humans has provided new opportunities to study contributors to FTC metastasis. This study evaluates the role of gelsolin, an actin-regulatory protein, in modulating the metastatic potential of FTC. Gelsolin was previously found by cDNA microarray analysis to be down-regulated in TRbeta(PV/PV) mice as compared with wild-type mice. This study found an age-dependent reduction of gelsolin protein abundance in TRbeta(PV/PV) mice as tumorigenesis progressed. Knockdown of gelsolin by small interfering RNA resulted in increased tumor cell motility and increased gelsolin expression by histone deacetylase inhibitor (trichostatin A) led to decreased cell motility. Additional biochemical analyses demonstrated that gelsolin physically interacted with TRbeta1 or PV in vivo and in vitro. The interaction regions were mapped to the C terminus of gelsolin and the DNA binding domain of TR. The physical interaction of gelsolin with PV reduced its binding to actin, leading to disarrayed cytoskeletal architectures. These results suggest that PV-induced alteration of the actin/gelsolin cytoskeleton contributes to increased cell motility. Thus, the present study uncovered a novel PV-mediated oncogenic pathway that could contribute to the local tumor progression and metastatic potential of thyroid carcinogenesis.

Building Integrated Photovoltaic Module-Based on Aluminum Substrate With Forced Water Cooling.

PubMed

Pang, Wei; Zhang, Yongzhe; Cui, Yanan; Yu, Hongwen; Liu, Yu; Yan, Hui

2018-04-01

The increase of operating temperature on a photovoltaic (PV) cell degrades its electrical efficiency. This paper is organized to describe our latest design of an aluminum substrate-based photovoltaic/thermal (PV/T) system. The electrical efficiency of the proposed PV/T can be increased by ∼ 20% in comparison with a conventional glass substrate-based PV. The work will benefit hybrid utilization of solar energy in development of building integrated photovoltaic systems.

Numerical modeling of uncertainty and variability in the technology, manufacturing, and economics of crystalline silicon photovoltaics

NASA Astrophysics Data System (ADS)

Ristow, Alan H.

2008-10-01

Electricity generated from photovoltaics (PV) promises to satisfy the world's ever-growing thirst for energy without significant pollution and greenhouse gas emissions. At present, however, PV is several times too expensive to compete economically with conventional sources of electricity delivered via the power grid. To ensure long-term success, must achieve cost parity with electricity generated by conventional sources of electricity. This requires detailed understanding of the relationship between technology and economics as it pertains to PV devices and systems. The research tasks of this thesis focus on developing and using four types of models in concert to develop a complete picture of how solar cell technology and design choices affect the quantity and cost of energy produced by PV systems. It is shown in this thesis that high-efficiency solar cells can leverage balance-of-systems (BOS) costs to gain an economic advantage over solar cells with low efficiencies. This advantage is quantified and dubbed the "efficiency premium." Solar cell device models are linked to models of manufacturing cost and PV system performance to estimate both PV system cost and performance. These, in turn, are linked to a model of levelized electricity cost to estimate the per-kilowatt-hour cost of electricity produced by the PV system. A numerical PV module manufacturing cost model is developed to facilitate this analysis. The models and methods developed in this thesis are used to propose a roadmap to high-efficiency multicrystalline-silicon PV modules that achieve cost parity with electricity from the grid. The impact of PV system failures on the cost of electricity is also investigated; from this, a methodology is proposed for improving the reliability of PV inverters.

Bean Metal-Responsive Element-Binding Transcription Factor Confers Cadmium Resistance in Tobacco1

PubMed Central

Sun, Na; Liu, Meng; Zhang, Wentao; Yang, Wanning; Bei, Xiujuan; Ma, Hui; Qiao, Fan; Qi, Xiaoting

2015-01-01

Cadmium (Cd) is highly toxic to plants. Modulation of Cd-responsive transcription is an important way for Cd detoxification in plants. Metal-responsive element (MRE) is originally described in animal metallothionein genes. Although functional MREs also exist in Cd-regulated plant genes, specific transcription factors that bind MRE to regulate Cd tolerance have not been identified. Previously, we showed that Cd-inducible bean (Phaseolus vulgaris) stress-related gene2 (PvSR2) produces a short (S) PvSR2 transcript (S-PvSR2) driven by an intronic promoter. Here, we demonstrate that S-PvSR2 encodes a bean MRE-binding transcription factor1 (PvMTF-1) that confers Cd tolerance in tobacco (Nicotiana tabacum). PvMTF-1 expression was up-regulated by Cd at the levels of RNA and protein. Importantly, expression of PvMTF-1 in tobacco enhanced Cd tolerance, indicating its role in regulating Cd resistance in planta. This was achieved through direct regulation of a feedback-insensitive Anthranilate Synthase α-2 chain gene (ASA2), which catalyzes the first step for tryptophan biosynthesis. In vitro and in vivo DNA-protein interaction studies further revealed that PvMTF-1 directly binds to the MRE in the ASA2 promoter, and this binding depends on the zinc finger-like motif of PvMTF-1. Through modulating ASA2 up-regulation by Cd, PvMTF-1 increased free tryptophan level and subsequently reduced Cd accumulation, thereby enhancing Cd tolerance of transgenic tobacco plants. Consistent with this observation, tobacco transiently overexpressing ASA2 also exhibited increased tolerance to Cd. We conclude that PvMTF-1 is a zinc finger-like transcription factor that links MRE to Cd resistance in transgenic tobacco through activation of tryptophan biosynthesis. PMID:25624396

Insolation-oriented model of photovoltaic module using Matlab/Simulink

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

Tsai, Huan-Liang

2010-07-15

This paper presents a novel model of photovoltaic (PV) module which is implemented and analyzed using Matlab/Simulink software package. Taking the effect of sunlight irradiance on the cell temperature, the proposed model takes ambient temperature as reference input and uses the solar insolation as a unique varying parameter. The cell temperature is then explicitly affected by the sunlight intensity. The output current and power characteristics are simulated and analyzed using the proposed PV model. The model verification has been confirmed through an experimental measurement. The impact of solar irradiation on cell temperature makes the output characteristic more practical. In addition,more » the insolation-oriented PV model enables the dynamics of PV power system to be analyzed and optimized more easily by applying the environmental parameters of ambient temperature and solar irradiance. (author)« less

In-situ X-Ray Analysis of Rapid Thermal Processing for Thin-Film Solar Cells: Closing the Gap between Production and Laboratory Efficiency

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

Toney, Michael F.; van Hest, Maikel F. A. M.

For materials synthesis, it is well known that the material final state may not reach equilibrium and depends on the synthetic process. In particular, processes that quickly remove the available energy from the material may leave it in a metastable state and the metastability may actually impart desirable functional properties. By its very nature, Rapid thermal processing (RTP) is ideally suited to produce such metastable materials. However, metastability and the dynamics of reaching a metastable state are poorly understood, since this is best accomplished through in situ monitoring. In this regard, RTP is particularly challenging as the processing time aremore » very short (seconds to minutes). As a result, there is only poor understanding, and hence use, of RTP in industry. This is potentially a cost-increasing limitation, because RTP can decrease cost by decreasing processing time, and as such, increase throughput and decrease the total thermal budget of processing - a significant cost. RTP is already being used for key processing steps in PV technologies. With silicon wafer PV, it is used for establishing electrical contact between the Ag metal grid and the silicon (known as firing). In this process, a silicon wafer with deposited metal/frit in a grid pattern is heated rapidly to temperatures between 750 and 800 ºC. The processing time when the temperature is held above 600ºC is short (<5 seconds). This process has historically been optimized empirically and it is unclear how the thermal processing affects formation of the final contact between the metal and the silicon. In the case of thin-film PV, RTP has been demonstrated in the process of making absorber layers, i.e. CIGS and CZTS. Use of RTP can reduce the processing time from 10s of minutes to seconds, reducing the thermal budget and increasing the throughput significantly. The conversion from precursor material to final PV material is not well understood, and most of the process optimization is done empirically. Again, the proposed in situ monitoring will provide insight into the conversion process. We have developed a unique instrument for in situ monitoring of the reaction process during RTP. The most fundamental property to monitor is the atomic arrangement (for solids, crystalline structure) and thus we have focused on this property. The chamber was designed to collect X-ray diffraction (XRD) for crystal phase determination, although it has lent insight in the formation of liquids. We designed and constructed both inert (air) and reactive (S/Se) versions of this chamber. We have applied the RTP-XRD methodology to: silicon solar cell electrical contact formation; the reaction sequence for forming CIGS PV thin films from copper selenide and indium gallium selenide precursors; the phase sequence for forming HC(NH2)2PbI3 (FAPbI3) and CH3NH3PbI3 (MAPbI3) hybrid-perovskite PV thin films. The RTP instrument enables real-time collection of X-ray diffraction data with intervals as short as 100 ms, and while heating at ramp rates as high 100 ºCs-1 up to 1200 ºC. The system is portable and can be installed on a synchrotron beamline. The RTP reactor consists of a metallic body (front cap assembly, central block and end cap assembly) that houses a quartz reaction chamber. The sample is secured inside the reaction chamber on a sample holder connected to the front-cap assembly. Modifications of the chamber were made for safely handling sulfur and selenium vapor environments. A Se/S source holder was added to generate a Se/S over pressure in the chamber on heating and the entrance window is made wider in order to accommodate the detachable additional holder. Se/S are toxic in nature and therefore a proper Se/S trapping is used before releasing the gases to exhaust. Screen-printing provides an economically attractive means for making Ag electrical contacts to Si solar cells, but the use of Ag substantiates a significant manufacturing cost, and the glass frit used in the paste to enable contact formation contains Pb. To achieve optimal electrical performance and to develop pastes with alternative, abundant, and non-toxic materials requires understanding the contact formation process during firing. We use the RTP-XRD chamber during firing of Ag-Si contacts to reveal the reaction sequence for contact formation. The findings show that between 500 ºC and 650 ºC PbO in the frit etches the SiNx antireflective-coating on the solar cell, exposing the Si surface. Then, above 650 ºC, Ag+ dissolves into the molten glass frit – key for enabling deposition of metallic Ag on the emitter surface and precipitation of Ag nanocrystals within the glass. This clarifies contact formation mechanisms and can be used to suggest approaches for development of inexpensive, nontoxic solar cell contacting pastes. We used the RTP/XRD chamber to study the formation of CuInGaS/Se (CIGS) PV films by in-situ selenization of pre-deposited metal stacks and annealing of pre-deposited Cu-In-Ga-Se precursors. During the metal stack selenization, we observed that Se first reacts with the metals and forms selenides. We observed formation of intermetallics such as Cu2In and binary selenides during heating. On further annealing in a Se atmosphere, CuInSe2 and CuGaSe2 forms which on heating up to 550 °C reacts further to form the CIGS phase. On prolonged exposure to 550 °C for more than 5 mins or higher temperature, we see separation into Ga-rich and Ga-depleted CIGS phases. On introducing a holding step at 400 °C for 10 min during the annealing ramp, the CIGS phase (forms between 500-550 °C), appears to be less prone to decomposition into high-Ga and low-Ga phases during holding at peak temperature. Lead halide perovskites have emerged as successful optoelectronic materials with high photovoltaic power conversion efficiencies and low material cost. However, substantial challenges remain in the scalability, stability and fundamental understanding of the materials. We demonstrated the application of radiative thermal annealing, an easily scalable processing method, for synthesizing formamidinium lead iodide (FAPbI3) perovskite solar absorbers. Devices fabricated from films formed via radiative thermal annealing have equivalent efficiencies to those annealed using a conventional hotplate. By coupling results from in situ x-ray diffraction using a radiative thermal annealing system with device performances, we mapped the processing phase space of FAPbI3 and corresponding device efficiencies. Our map of processing-structure-performance space suggests the commonly used FAPbI3 annealing time, 10 min at 170 °C, can be significantly reduced to 40 s at 170 °C without affecting the photovoltaic performance. Applying the Johnson-Mehl-Avrami model to the decomposition into PbI2, the activation energy was determined. We also presented a well-controlled, manufacturing relevant annealing method, radiative thermal annealing, for the methylammonium lead triiodide films formed by solvent engineering process, with dimethylformamide (DMF) and dimethyl sulfoxide as solvent and diethyl ether as the antisolvent. Radiative thermal annealing can produce high quality perovskite films, evidenced by high efficiency solar cell devices, in a shorter time than the widely-used hotplate annealing. Using in-situ x-ray diffraction during the radiative annealing, we show that the role of the antisolvent is not to form an intermediate compound (a methylammonium iodide, lead iodide, and dimethyl sulfoxide compound) by washing of the main solvent (DMF) but to achieve a pin-hole free, uniform film of methylammonium lead iodide. We find that having the intermediate compound does not guarantee a high quality (pin-hole free) perovskite film. Our study was extended to reveal the effect of annealing environment, annealing temperature profile, and deposition substrate.« less

CIGS thin film solar cell prepared by reactive co-sputtering

NASA Astrophysics Data System (ADS)

Kim, Jeha; Lee, Ho-Sub; Park, Nae-Man

2013-09-01

The reactive co-sputtering was developed as a new way of preparing high quality CuInGaSe2(CIGS) films from two sets of targets; Cu0.6Ga 0.4 and Cu0.4In0.6 alloy and Cu and (In0.7Ga0.3)2Se3 compound targets. During sputtering, Cu, In, Ga metallic elements as well as the compound materials were reacted to form CIGS simultaneously in highly reactive elemental Se atmosphere generated by a thermal cracker. CIGS layer had been grown on Mo/soda-lime glass(SLG) at 500°C. For both sets of targets, we controlled the composition of CIGS thin film by changing the RF power for target components. All the films showed a preferential (112) orientation as observed from X-ray diffraction analysis. The composition ratios of CIGS were easily set to 0.71-0.95, 0.10-0.30 for [Cu]/[III] and [Ga]/[III], respectively. The grain size and the surface roughness of a CIGS film increased as the [Cu]/[III] ratios increased. The solar cells were fabricated using a standard base line process in the device structure of grid/ITO/i-ZnO/CdS/CIGS/Mo/ SLG. The best performance was obtained the performance of Voc = 0.45 V, Jsc =35.6, FF = 0.535, η = 8.6% with a 0.9 μm-CIGS solar cell from alloy targets while Voc = 0.54 V, Jsc =30.8, FF = 0.509, η = 8.5% with a 0.8 μm-CIGS solar cell from Cu and (In0.7Ga0.3)2Se3.

Tobacco toxicant exposure in cigarette smokers who use or do not use other tobacco products.

PubMed

Nollen, Nicole L; Mayo, Matthew S; Clark, Lauren; Cox, Lisa Sanderson; Khariwala, Samir S; Pulvers, Kim; Benowitz, Neal L; Ahluwalia, Jasjit S

2017-10-01

Non-cigarette other tobacco products (OTP; e.g., cigarillos, little cigars) are typically used in combination with cigarettes, but limited data exists on the tobacco toxicant exposure profiles of dual cigarette-OTP (Cig-OTP) users. This study examined biomarkers of nicotine and carcinogen exposure in cigarette smokers who used or did not use OTP. 111 Cig-OTP and 111 cigarette only (Cig Only) users who smoked equivalent cigarettes per day were matched on age (< 40, >=40), race (African American, White), and gender. Participants reported past 7-day daily use of cigarettes and OTP and provided urine for nicotine, cotinine, total nicotine equivalents (TNE) and total NNAL concentrations. Cig-OTP users reported greater past 7-day tobacco use (15.9 versus 13.0 products/day, p<0.01) but had significantly lower creatinine-normalized nicotine (606 versus 1301ng/mg), cotinine (1063 versus 2125ng/mg), TNE (28 versus 57 nmol/mg) and NNAL (251 versus 343pg/mg) than Cig Only users (p<0.001). Cig-OTP users had lower levels of nicotine and metabolites of a lung carcinogen relative to Cig-Only users, but concentrations of toxicants among Cig-OTP users were still at levels that place smokers at great risk from the detrimental health effects of smoking. Our study finds that nicotine and carcinogen exposure in Cig-OTP users are lower compared to cigarette only users, but still likely to be associated with substantial harm. A better understanding of why toxicant levels may be lower in Cig-OTP is an important area for future study. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a questionnaire for assessing dependence on electronic cigarettes among a large sample of ex-smoking E-cigarette users.

PubMed

Foulds, Jonathan; Veldheer, Susan; Yingst, Jessica; Hrabovsky, Shari; Wilson, Stephen J; Nichols, Travis T; Eissenberg, Thomas

2015-02-01

Electronic cigarettes (e-cigs) are becoming increasingly popular, but little is known about their dependence potential. This study aimed to assess ratings of dependence on electronic cigarettes and retrospectively compare them with rated dependence on tobacco cigarettes among a large sample of ex-smokers who switched to e-cigs. A total of 3,609 current users of e-cigs who were ex-cigarette smokers completed a 158-item online survey about their e-cig use, including 10 items designed to assess their previous dependence on cigarettes and 10 almost identical items, worded to assess their current dependence on e-cigs (range 0-20). Scores on the 10-item Penn State (PS) Cigarette Dependence Index were significantly higher than on the comparable PS Electronic Cigarette Dependence Index (14.5 vs. 8.1, p < .0001). In multivariate analysis, those who had used e-cigs longer had higher e-cig dependence scores, as did those using more advanced e-cigs that were larger than a cigarette and had a manual button. Those using zero nicotine liquid had significantly lower e-cig dependence scores than those using 1-12 mg/ml, who scored significantly lower than those using 13 or greater mg/ml nicotine liquid (p < .003). Current e-cigarette users reported being less dependent on e-cigarettes than they retrospectively reported having been dependent on cigarettes prior to switching. E-cig dependence appears to vary by product characteristics and liquid nicotine concentration, and it may increase over time. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Electronic cigarette aerosols and copper nanoparticles induce mitochondrial stress and promote DNA fragmentation in lung fibroblasts

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

Lerner, Chad A.; Rutagarama, Pierrot; Ahmad, Tanveer

Oxidants or nanoparticles have recently been identified as constituents of aerosols released from various styles of electronic cigarettes (E-cigs). Cells in the lung may be directly exposed to these constituents and harbor reactive properties capable of incurring acute cell injury. Our results show mitochondria are sensitive to both E-cig aerosols and aerosol containing copper nanoparticles when exposed to human lung fibroblasts (HFL-1) using an Air-Liquid Interface culture system, evident by elevated levels of mitochondrial ROS (mtROS). Increased mtROS after aerosol exposure is associated with reduced stability of OxPhos electron transport chain (ETC) complex IV subunit and nuclear DNA fragmentation. Increasedmore » levels of IL-8 and IL-6 in HFL-1 conditioned media were also observed. These findings reveal both mitochondrial, genotoxic, and inflammatory stresses are features of direct cell exposure to E-cig aerosols which are ensued by inflammatory duress, raising a concern on deleterious effect of vaping. - Graphical abstract: Oxidants and possibly reactive properties of metal particles in E-cig aerosols impart mitochondrial oxidative stress and DNA damage. These biological effects accompany inflammatory response which may raise concern regarding long term E-cig use. Mitochondria may be particularly sensitive to reactive properties of E-cig aerosols in addition to the potential for them to induce genotoxic stress by generating increased ROS. - Highlights: • Mitochondria are sensitive to both E-cig aerosols and metal nanoparticles. • Increased mtROS by E-cig aerosol is associated with disrupted mitochondrial energy. • E-cig causes nuclear DNA fragmentation. • E-cig aerosols induce pro-inflammatory response in human fibroblasts.« less

Historical Analysis of Champion Photovoltaic Module Efficiencies

DOE PAGES

Kurtz, Sarah; Repins, Ingrid; Metzger, Wyatt K.; ...

2018-02-14

Champion photovoltaic (PV) cell and module efficiencies have been reported in Progress in PV since 1993. Following the evolution of these efficiencies enables researchers to track the progress of various technologies. National Renewable Energy Laboratory has maintained a historical chart of the champion cell efficiencies, but has not published a similar chart of champion module efficiencies. Here, we analyze champion module efficiencies and compare them to champion cell efficiencies to better understand technology trends over the last three decades, highlighting that, in some cases, module efficiencies exceed 90% of cell efficiencies. Recommendations are provided on how to change the datamore » collection and reporting for champion efficiencies to increase the value of these records.« less

Historical Analysis of Champion Photovoltaic Module Efficiencies

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

Kurtz, Sarah; Repins, Ingrid; Metzger, Wyatt K.

Champion photovoltaic (PV) cell and module efficiencies have been reported in Progress in PV since 1993. Following the evolution of these efficiencies enables researchers to track the progress of various technologies. National Renewable Energy Laboratory has maintained a historical chart of the champion cell efficiencies, but has not published a similar chart of champion module efficiencies. Here, we analyze champion module efficiencies and compare them to champion cell efficiencies to better understand technology trends over the last three decades, highlighting that, in some cases, module efficiencies exceed 90% of cell efficiencies. Recommendations are provided on how to change the datamore » collection and reporting for champion efficiencies to increase the value of these records.« less

Performance testing and module monitoring at the EC Necessary steps to develop cost-effective PV modules

NASA Astrophysics Data System (ADS)

Krebs, K.

Testing programs carried out by the European Communities to establish testing techniques and standards for verifying the reliability and integrity of solar cells intended for the marketplace are described. The efforts are being expended to assure quality control and certification for photovoltaic (PV) products manufactured in any of the member nations. The failure rate for PV modules was lowered to 0.5 pct/year by 1981, and single cell failures are projected to be lowered to 0.00001/yr, connectors to 0.001/yr, and batteries to 0.01/yr. Day/night thermal cycling causes the most dominant type of failures, i.e., cracked cells and interconnect defects. Tests have been standardized for inspection, verification, performance, mechanical loading, hail impact, damp heat, high temperature long exposure, hot-spot heating, thermal cycling, and humidity-freezing tolerance.

Energy production estimation for Kosh-Agach grid-tie photovoltaic power plant for different photovoltaic module types

NASA Astrophysics Data System (ADS)

Gabderakhmanova, T. S.; Kiseleva, S. V.; Frid, S. E.; Tarasenko, A. B.

2016-11-01

This paper is devoted to calculation of yearly energy production, demanded area and capital costs for first Russian 5 MW grid-tie photovoltaic (PV) plant in Altay Republic that is named Kosh-Agach. Simple linear calculation model, involving average solar radiation and temperature data, grid-tie inverter power-efficiency dependence and PV modules parameters is proposed. Monthly and yearly energy production, equipment costs and demanded area for PV plant are estimated for mono-, polycrystalline and amorphous modules. Calculation includes three types of initial radiation and temperature data—average day for every month from NASA SSE, average radiation and temperature for each day of the year from NASA POWER and typical meteorology year generated from average data for every month. The peculiarities for each type of initial data and their influence on results are discussed.

[Focus on electronic cigarettes].

PubMed

Tinghino, Biagio; Pacifici, Roberta; Di Pucchio, Alessandra; Palmi, Ilaria; Solimini, Renata; Faggiano, Fabrizio; Gorini, Giuseppe

2013-01-01

There is no clear regulation on electronic cigarettes (e-cig); their health effects are not yet fully investigated and there is insufficient standardisation and quality control of the product. Moreover, the e-cig could be a gateway for young people to nicotine addiction and traditional cigarette smoking. In Italy, the Ministry of Health banned the sale of e-cig with nicotine firstly to adolescents aged <16 years, then to people <18 years. Until further scientific evidence is available, it is mandatory to regulate the production and marketing of e-cigs, to make them less attractive, to forbid their use in enclosed areas, and prevent them from being promoted. E-cigs, however, seem to be much less dangerous than traditional cigarettes, although the few studies conducted are not sufficient to demonstrate either a clear therapeutic efficacy of e-cig or their total harmlessness. If e-cig had a known content, were made according to clear rules and in certified laboratories, without toxic substances, it could be used to help heavy smokers to quit, or at least to reduce smoking habits. There is a large proportion of smokers who are unable to quit. The revision of the European Directive (the proposal is being evaluated and we are waiting for its final approval) on tobacco recommends free sale for a minority of e-cigs only, those with a nicotine content <4 mg/ml. This will be difficult, considering that the business is just the free sale of e-cig and the much more dangerous tobacco cigarettes are still sold without any restriction.

Modeling and Simulation of a Dual-Junction CIGS Solar Cell Using Silvaco ATLAS

DTIC Science & Technology

2012-12-01

junction Copper Indium Gallium Selenide (CIGS) photovoltaic cell is investigated in this thesis. Research into implementing a dual-junction solar cell...Silvaco ATLASTM model of a single CIGS cell was created by utilizing actual solar cell parameters (such as layer thicknesses, gallium ratio, doping...THIS PAGE INTENTIONALLY LEFT BLANK v ABSTRACT The potential of designing a dual-junction Copper Indium Gallium Selenide (CIGS) photovoltaic

Fabrication of CIGS Films by Electrodeposition Method for Photovoltaic Cells

NASA Astrophysics Data System (ADS)

Lee, Hyunju; Yoon, Hyukjoo; Ji, Changwook; Lee, Dongyun; Lee, Jae-Ho; Yun, Jae-Ho; Kim, Yangdo

2012-12-01

Cu(InGa)Se2 (CIGS) thin films were fabricated by electrochemical deposition in a single bath containing Cu, In, Ga, and Se ions. The electrolyte was prepared by dissolving CuCl2, InCl3, GaCl3, H2SeO3, and LiCl in deionized water. The potentiostatic deposition process was achieved by applying a voltage ranging from -0.5 V to -0.8 V versus Ag/AgCl. The effects of different chemical bath concentrations on the film composition and morphology were investigated. Stoichiometric CIGS film composition could be achieved by controlling the chemical compositions of the bath and the voltage. Gelatin was added to the solution to improve the surface and microstructures of the CIGS film. The as-deposited films were annealed at 500°C in Ar atmosphere for crystallization. The structural, morphological, and compositional properties of the CIGS thin films before and after annealing were examined by x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. This study showed that the composition of the CIGS films is dependent on the bath concentration, whereas the applied potential had relatively less effect on the CIGS film composition. In addition, the use of gelatin helped in the fabrication of crack-free CIGS thin films with greatly improved surface morphology.

[Smoking fewer cigarettes per day may determine a significant risk reduction in developing smoking attributable diseases? Is there a risk reduction for e-cigarette users?].

PubMed

Pieri, Luca; Chellini, Elisabetta; Gorini, Giuseppe

2014-01-01

Among Italian smokers--about 10 millions in 2013--about 600,000 began using electronic cigarettes (e-cigs) in last years. About 10% of e-cig users quitted smoking tobacco, whereas the 90% was dual users. Among them, about three out of four decreased the number of cigarettes smoked per day (cig/day), but did not quit. How many fewer cigarettes a smoker has to smoke to obtain significant health benefits? Is there a threshold? In order to observe a significant 27% reduction in the risk of developing lung cancer, a smoker must reduce the number of cig/day by at least 50%, while for the other smoking-related diseases (acute myocardial infarction - AMI, stroke, chronic obstructive pulmonary diseases), halving the number of cig/day did not drive to a significant risk reduction. Even smoking 5 cig/day increases the risk of AMI, whereas it significantly lowers the risk of lung cancer. Obviously, quitting smoking is the best choice to highly reduce risks for all smoking-related diseases. Therefore, in order to achieve significant risk reductions, e-cig users should quit smoking as first choice, or, if they feel it is impossible to them, reduce the consumption of traditional cigarettes to less than 5 cig/day.

A Novel Approach to Thermal Design of Solar Modules: Selective-Spectral and Radiative Cooling

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

Sun, Xingshu; Dubey, Rajiv; Chattopadhyay, Shashwata

2016-11-21

For commercial solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 degrees C higher than the ambient. In the long run, extreme self-heating may erode efficiency and shorten lifetime, thereby, dramatically reducing the total energy output by almost ~10% Therefore, it is critically important to develop effective and practical cooling methods to combat PV self-heating. In this paper, we explore two fundamental sources of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical and thermal properties of the solar module to eliminatemore » the parasitic absorption (selective-spectral cooling) and enhance the thermal emission to the cold cosmos (radiative cooling). The proposed technique should cool the module by ~10 degrees C, to be reflected in significant long-term energy gain (~ 3% to 8% over 25 years) for PV systems under different climatic conditions.« less

Space Station Freedom electric power system availability study

NASA Technical Reports Server (NTRS)

Turnquist, Scott R.

1990-01-01

The results are detailed of follow-on availability analyses performed on the Space Station Freedom electric power system (EPS). The scope includes analyses of several EPS design variations, these are: the 4-photovoltaic (PV) module baseline EPS design, a 6-PV module EPS design, and a 3-solar dynamic module EPS design which included a 10 kW PV module. The analyses performed included: determining the discrete power levels that the EPS will operate at upon various component failures and the availability of each of these operating states; ranking EPS components by the relative contribution each component type gives to the power availability of the EPS; determining the availability impacts of including structural and long-life EPS components in the availability models used in the analyses; determining optimum sparing strategies, for storing space EPS components on-orbit, to maintain high average-power-capability with low lift-mass requirements; and analyses to determine the sensitivity of EPS-availability to uncertainties in the component reliability and maintainability data used.

Use of Melt Flow Rate Test in Reliability Study of Thermoplastic Encapsulation Materials in Photovoltaic Modules

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

Moseley, J.; Miller, D.; Shah, Q.-U.-A. S. J.

2011-10-01

Use of thermoplastic materials as encapsulants in photovoltaic (PV) modules presents a potential concern in terms of high temperature creep, which should be evaluated before thermoplastics are qualified for use in the field. Historically, the issue of creep has been avoided by using thermosetting polymers as encapsulants, such as crosslinked ethylene-co-vinyl acetate (EVA). Because they lack crosslinked networks, however, thermoplastics may be subject to phase transitions and visco-elastic flow at the temperatures and mechanical stresses encountered by modules in the field, creating the potential for a number of reliability and safety issues. Thermoplastic materials investigated in this study include PV-grademore » uncured-EVA (without curing agents and therefore not crosslinked); polyvinyl butyral (PVB); thermoplastic polyurethane (TPU); and three polyolefins (PO), which have been proposed for use as PV encapsulation. Two approaches were used to evaluate the performance of these materials as encapsulants: module-level testing and a material-level testing.« less

ANN based Real-Time Estimation of Power Generation of Different PV Module Types

NASA Astrophysics Data System (ADS)

Syafaruddin; Karatepe, Engin; Hiyama, Takashi

Distributed generation is expected to become more important in the future generation system. Utilities need to find solutions that help manage resources more efficiently. Effective smart grid solutions have been experienced by using real-time data to help refine and pinpoint inefficiencies for maintaining secure and reliable operating conditions. This paper proposes the application of Artificial Neural Network (ANN) for the real-time estimation of the maximum power generation of PV modules of different technologies. An intelligent technique is necessary required in this case due to the relationship between the maximum power of PV modules and the open circuit voltage and temperature is nonlinear and can't be easily expressed by an analytical expression for each technology. The proposed ANN method is using input signals of open circuit voltage and cell temperature instead of irradiance and ambient temperature to determine the estimated maximum power generation of PV modules. It is important for the utility to have the capability to perform this estimation for optimal operating points and diagnostic purposes that may be an early indicator of a need for maintenance and optimal energy management. The proposed method is accurately verified through a developed real-time simulator on the daily basis of irradiance and cell temperature changes.

NREL Report Shows Utility-Scale Solar PV System Cost Fell Nearly 30% Last

Science.gov Websites

Year | NREL | News | NREL Report Shows Utility-Scale Solar PV System Cost Fell Nearly 30% Last Year News Release: NREL Report Shows Utility-Scale Solar PV System Cost Fell Nearly 30% Last Year September 12, 2017 Record-low costs enabled by decline in module and inverter prices The installed cost of

NREL Report Shows U.S. Solar Photovoltaic Costs Continuing to Fall in 2016

Science.gov Websites

chart of solar pv costs from q4 2009 to q1 2016 NREL U.S. PV system cost benchmarks, from the fourth (NREL). Driving the cost reductions were lower module and inverter prices, increased competition, lower ;The continuing total cost decline of solar PV systems demonstrates the sustained economic

Golden Rays - November 2016 | Solar Research | NREL

Science.gov Websites

develop PV module materials for reliable, low-cost solar electricity. Photo of three individuals behind quantum dots. Photo of a man inside a room with manufacturing equipment NREL Report Shows U.S. Solar PV sustained economic competitiveness of solar PV for the industry across all three sectors. Must Reads

Proposed acceptance, qualification, and characterization tests for thin-film PV modules

NASA Technical Reports Server (NTRS)

Waddington, D.; Mrig, L.; Deblasio, R.; Ross, R.

1988-01-01

Details of a proposed test program for PV thin-film modules which the Department of Energy has directed the Solar Energy Research Institute (SERI) to prepare are presented. Results of one of the characterization tests that SERI has performed are also presented. The objective is to establish a common approach to testing modules that will be acceptable to both users and manufacturers. The tests include acceptance, qualification, and characterization tests. Acceptance tests verify that randomly selected modules have similar characteristics. Qualification tests are based on accelerated test methods designed to simulate adverse conditions. Characterization tests provide data on performance in a predefined environment.

Solar concentrator modules with silicone-on-glass Fresnel lens panels and multijunction cells.

PubMed

Rumyantsev, Valery D

2010-04-26

High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

Final Report: Rational Design of Wide Band Gap Buffer Layers for High-Efficiency Thin-Film Photovoltaics

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

Lordi, Vincenzo

The main objective of this project is to enable rational design of wide band gap buffer layer materials for CIGS thin-film PV by building understanding of the correlation of atomic-scale defects in the buffer layer and at the buffer/absorber interface with device electrical properties. Optimized wide band gap buffers are needed to reduce efficiency loss from parasitic absorption in the buffer. The approach uses first-principles materials simulations coupled with nanoscale analytical electron microscopy as well as device electrical characterization. Materials and devices are produced by an industrial partner in a manufacturing line to maximize relevance, with the goal of enablingmore » R&D of new buffer layer compositions or deposition processes to push device efficiencies above 21%. Cadmium sulfide (CdS) is the reference material for analysis, as the prototypical high-performing buffer material.« less

Multifunctional microstructured polymer films for boosting solar power generation of silicon-based photovoltaic modules.

PubMed

Leem, Jung Woo; Choi, Minkyu; Yu, Jae Su

2015-02-04

We propose two-dimensional periodic conical micrograting structured (MGS) polymer films as a multifunctional layer (i.e., light harvesting and self-cleaning) at the surface of outer polyethylene terephthalate (PET) cover-substrates for boosting the solar power generation in silicon (Si)-based photovoltaic (PV) modules. The surface of ultraviolet-curable NOA63 MGS polymer films fabricated by the soft imprint lithography exhibits a hydrophobic property with water contact angle of ∼121° at no inclination and dynamic advancing/receding water contact angles of ∼132°/111° at the inclination angle of 40°, respectively, which can remove dust particles or contaminants on the surface of PV modules in real outdoor environments (i.e., self-cleaning). The NOA63 MGS film coated on the bare PET leads to the reduction of reflection as well as the enhancement of both the total and diffuse transmissions at wavelengths of 300-1100 nm, indicating lower solar weighted reflectance (RSW) of ∼8.2%, higher solar weighted transmittance (TSW) of ∼93.1%, and considerably improved average haze ratio (HAvg) of ∼88.3% as compared to the bare PET (i.e., RSW ≈ 13.5%, TSW ≈ 86.9%, and HAvg ≈ 9.1%), respectively. Additionally, it shows a relatively good durability at temperatures of ≤160 °C. The resulting Si PV module with the NOA63 MGS/PET has an enhanced power conversion efficiency (PCE) of 13.26% (cf., PCE = 12.55% for the reference PV module with the bare PET) due to the mainly improved short circuit current from 49.35 to 52.01 mA, exhibiting the PCE increment percentage of ∼5.7%. For light incident angle-dependent PV module current-voltage characteristics, superior solar energy conversion properties are also obtained in a broad angle range of 10-80°.

Effectiveness of the electronic cigarette: An eight-week Flemish study with six-month follow-up on smoking reduction, craving and experienced benefits and complaints.

PubMed

Adriaens, Karolien; Van Gucht, Dinska; Declerck, Paul; Baeyens, Frank

2014-10-29

Smoking reduction remains a pivotal issue in public health policy, but quit rates obtained with traditional quit-smoking therapies remain disappointingly low. Tobacco Harm Reduction (THR), aiming at less harmful ways of consuming nicotine, may provide a more effective alternative. One promising candidate for THR are electronic cigarettes (e-cigs). The aim of this study was to investigate the efficacy of second-generation e-cigs both in terms of acute craving-reduction in the lab and in terms of smoking reduction and experienced benefits/complaints in an eight-month Randomized Controlled Trial (RCT). RCT with three arms. Participants (N = 48) unwilling to quit smoking were randomized into two e-cig groups and one control group. During three lab sessions (over two months) participants, who had been abstinent for four hours, vaped/smoked for five minutes, after which we monitored the effect on craving and withdrawal symptoms. eCO and saliva cotinine levels were also measured. In between lab sessions, participants in the e-cig groups could use e-cigs or smoke ad libitum, whereas the control group could only smoke. After the lab sessions, the control group also received an e-cig. The RCT included several questionnaires, which repeatedly monitored the effect of ad libitum e-cig use on the use of tobacco cigarettes and the experienced benefits/complaints up to six months after the last lab session. From the first lab session on, e-cig use after four hours of abstinence resulted in a reduction in cigarette craving which was of the same magnitude as when a cigarette was smoked, while eCO was unaffected. After two months, we observed that 34% of the e-cig groups had stopped smoking tobacco cigarettes, versus 0% of the control group. After five months, the e-cig groups demonstrated a total quit-rate of 37%, whereas the control group showed a quit rate of 38% three months after initiating e-cig use. At the end of the eight-month study, 19% of the e-cig groups and 25% of the control group were totally abstinent from smoking, while an overall reduction of 60% in the number of cigarettes smoked per day was observed (compared to intake). eCO levels decreased, whereas cotinine levels were the same in all groups at each moment of measurement. Reported benefits far outweighed the reported complaints. In a series of controlled lab sessions with e-cig naïve tobacco smokers, second generation e-cigs were shown to be immediately and highly effective in reducing abstinence induced cigarette craving and withdrawal symptoms, while not resulting in increases in eCO. Remarkable (>50 pc) eight-month reductions in, or complete abstinence from tobacco smoking was achieved with the e-cig in almost half (44%) of the participants.

Successful Nicotine Intake in Medical Assisted Use of E-Cigarettes: A Pilot Study.

PubMed

Pacifici, Roberta; Pichini, Simona; Graziano, Silvia; Pellegrini, Manuela; Massaro, Giuseppina; Beatrice, Fabio

2015-07-08

The electronic cigarette (e-cig) has gained popularity as an aid in smoking cessation programs mainly because it maintains the gestures and rituals of tobacco smoking. However, it has been shown in inexperienced e-cig users that ineffective nicotine delivery can cause tobacco craving that could be responsible for unsuccessful smoking reduction/cessation. Moreover, the incorrect use of an e-cig could also led to potential nicotine overdosage and intoxication. Medically assisted training on the proper use of an e-cig plus behavioral support for tobacco dependence could be a pivotal step in avoiding both issues. We performed an eight-month pilot study of adult smokers who started e-cig use after receiving a multi-component medically assisted training program with monitoring of nicotine intake as a biomarker of correct e-cig use. Participants were tested during follow-up for breath carbon monoxide (CO), plasma cotinine and trans-3'-hydroxycotinine, and number of tobacco cigarettes smoked. At the end of the first, fourth, and eighth month of follow-up, 91.1, 73.5, and 76.5% of participants respectively were e-cig users ('only e-cig' and 'dual users'). They showed no significant variation in plasma cotinine and trans-3'-hydroxycotinine with respect to the start of the study when they smoked only tobacco cigarettes, but a significant reduction in breath CO. The proposed medically assisted training program of e-cig use led to a successful nicotine intake, lack of typical cigarette craving and overdosage symptoms and a significant decrease in the biomarker of cigarette combustion products.

Development of a Solar Cell Back Sheet with Excellent UV Durability and Thermal Conductivity.

PubMed

Kang, Seong-Hwan; Choi, Jaeho; Lee, Sung-Ho; Song, Young-Hoon; Park, Jong-Se; Jung, In-Sung; Jung, Jin-Su; Kim, Chong-Yeal; Yang, O-Bong

2018-09-01

The back sheet is one of the most important materials in photovoltaic (PV) modules. It plays an important role in protecting the solar cell from the environment by preventing moisture penetration. In the back sheet, the outermost layer is composed of a polyester (PET) film to protect the PV module from moisture, and the opposite layer is composed of a TiO2 + PE material. Nowadays, PV modules are installed in the desert. Therefore, methods to improve the power generation efficiency of PV modules need to be investigated as the efficiency is affected by temperature resulting from the heat radiation effect. Using a back sheet with a high thermal conductivity, the module output efficiency can be increased as heat is efficiently dissipated. In this study, a thermally conductive film was fabricated by mixing a reference film (TiO2 + PE) and a non-metallic material, MgO, with high thermal conductivity. UV irradiation tests of the film were conducted. The thermally conductive film (TiO2 + PE + MgO) showed higher conductivity than a reference film. No visible cracks and low yellowing degree were found in thermally conductive film, confirming its excellent UV durability characteristics. The sample film was bonded to a PET layer, and a back sheet was fabricated. The yellowing of the back sheet was also analyzed after UV irradiation. In addition, mini modules with four solar cell were fabricated using the developed back sheet, and a comparative outdoor test was conducted. The results showed that power generation improved by 1.38%.

Mitigation of PID in commercial PV modules using current interruption method

NASA Astrophysics Data System (ADS)

Bora, Birinchi; Oh, Jaewon; Tatapudi, Sai; Sastry, Oruganty S.; Kumar, Rajesh; Prasad, Basudev; Tamizhmani, Govindasamy

2017-08-01

Potential-induced degradation (PID) is known to have a very severe effect on the reliability of PV modules. PID is caused due to the leakage of current from the cell circuit to the grounded frame under humid conditions of high voltage photovoltaic (PV) systems. There are multiple paths for the current leakage. The most dominant leakage path is from the cell to the frame through encapsulant, glass bulk and glass surface. This dominant path can be prevented by interrupting the electrical conductivity at the glass surface. In our previous works related to this topic, we demonstrated the effectiveness of glass surface conductivity interruption technique using one-cell PV coupons. In this work, we demonstrate the effectiveness of this technique using a full size commercial module susceptible to PID. The interruption of surface conductivity of the commercial module was achieved by attaching a narrow, thin flexible glass strips, from Corning, called Willow Glass on the glass surface along the inner edges of the frame. The flexible glass strip was attached to the module glass surface by heating the glass strip with an ionomer adhesive underneath using a handheld heat gun. The PID stress test was performed at 60°C and 85% RH for 96 hours at -600 V. Pre- and post-PID characterizations including I-V and electroluminescence were carried out to determine the performance loss and affected cell areas. This work demonstrates that the PID issue can be effectively addressed by using this current interruption technique. An important benefit of this approach is that this interruption technique can be applied after manufacturing the modules and after installing the modules in the field as well.

Estimating the Effects of Module Area on Thin-Film Photovoltaic System Costs: Preprint

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

Horowitz, Kelsey A; Fu, Ran; Silverman, Timothy J

We investigate the potential effects of module area on the cost and performance of photovoltaic systems. Applying a bottom-up methodology, we analyzed the costs associated with thin-film modules and systems as a function of module area. We calculate a potential for savings of up to 0.10 dollars/W and 0.13 dollars/W in module manufacturing costs for CdTe and CIGS respectively, with large area modules. We also find that an additional 0.04 dollars/W savings in balance-of-systems costs may be achieved. Sensitivity of the dollar/W cost savings to module efficiency, manufacturing yield, and other parameters is presented. Lifetime energy yield must also bemore » maintained to realize reductions in the levelized cost of energy; the effects of module size on energy yield for monolithic thin-film modules are not yet well understood. Finally, we discuss possible non-cost barriers to adoption of large area modules.« less

An over 18%-efficiency completely buffer-free Cu(In,Ga)Se2 solar cell

NASA Astrophysics Data System (ADS)

Ishizuka, Shogo; Nishinaga, Jiro; Koida, Takashi; Shibata, Hajime

2018-07-01

In this letter, an independently certified photovoltaic efficiency of 18.4% demonstrated from a completely buffer-layer-free Cu(In,Ga)Se2 (CIGS) solar cell is reported. A Si-doped CIGS thin film was used as the photoabsorber layer and a conductive B-doped ZnO (BZO) front electrode layer was directly deposited on the CIGS layer. Metastable acceptor activation by heat-light soaking treatment was performed to maximize the efficiency. The results presented here are expected to serve as a benchmark for simplified-structure CIGS devices as well as a reference for discussions on the role of buffer layers used in conventional CIGS solar cells.

Simulated potential for enhanced performance of mechanically stacked hybrid III–V/Si tandem photovoltaic modules using DC–DC converters

DOE PAGES

MacAlpine, Sara; Bobela, David C.; Kurtz, Sarah; ...

2017-10-01

This work examines a tandem module design with GaInP2 mechanically stacked on top of crystalline Si, using a detailed photovoltaic (PV) system model to simulate four-terminal (4T) unconstrained and two-terminal voltage-matched (2T VM) parallel architectures. Module-level power electronics is proposed for the 2T VM module design to enhance its performance over the breadth of temperatures experienced by a typical PV installation. Annual, hourly simulations of various scenarios indicate that this design can reduce annual energy losses to ~0.5% relative to the 4T module configuration. Consideration is given to both performance and practical design for building or ground mount installations, emphasizingmore » compatibility with existing standard Si modules.« less

Simulated potential for enhanced performance of mechanically stacked hybrid III–V/Si tandem photovoltaic modules using DC–DC converters

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

MacAlpine, Sara; Bobela, David C.; Kurtz, Sarah

This work examines a tandem module design with GaInP2 mechanically stacked on top of crystalline Si, using a detailed photovoltaic (PV) system model to simulate four-terminal (4T) unconstrained and two-terminal voltage-matched (2T VM) parallel architectures. Module-level power electronics is proposed for the 2T VM module design to enhance its performance over the breadth of temperatures experienced by a typical PV installation. Annual, hourly simulations of various scenarios indicate that this design can reduce annual energy losses to ~0.5% relative to the 4T module configuration. Consideration is given to both performance and practical design for building or ground mount installations, emphasizingmore » compatibility with existing standard Si modules.« less

Simulated potential for enhanced performance of mechanically stacked hybrid III-V/Si tandem photovoltaic modules using DC-DC converters

NASA Astrophysics Data System (ADS)

MacAlpine, Sara; Bobela, David C.; Kurtz, Sarah; Lumb, Matthew P.; Schmieder, Kenneth J.; Moore, James E.; Walters, Robert J.; Alberi, Kirstin

2017-10-01

This work examines a tandem module design with GaInP2 mechanically stacked on top of crystalline Si, using a detailed photovoltaic (PV) system model to simulate four-terminal (4T) unconstrained and two-terminal voltage-matched (2T VM) parallel architectures. Module-level power electronics is proposed for the 2T VM module design to enhance its performance over the breadth of temperatures experienced by a typical PV installation. Annual, hourly simulations of various scenarios indicate that this design can reduce annual energy losses to ˜0.5% relative to the 4T module configuration. Consideration is given to both performance and practical design for building or ground mount installations, emphasizing compatibility with existing standard Si modules.

The AC photovoltaic module is here!

NASA Astrophysics Data System (ADS)

Strong, Steven J.; Wohlgemuth, John H.; Wills, Robert H.

1997-02-01

This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module's output is connected directly to the building's conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding).

Effects of using electronic cigarettes on nicotine delivery and cardiovascular function in comparison with regular cigarettes.

PubMed

Yan, X Sherwin; D'Ruiz, Carl

2015-02-01

The development of electronic cigarettes (e-cigs) has the potential to offer a less harmful alternative for tobacco users. This clinical study was designed to characterize e-cig users' exposure to nicotine, and to investigate the acute effects of e-cigs on the hemodynamic measurements (blood pressure and heart rate) in comparison with the effects of regular smoking. Five e-cigs and one Marlboro® cigarette were randomized for twenty-three participants under two exposure scenarios from Day 1 to Day 11: half-hour controlled administration and one hour ad lib use. The nicotine plasma concentrations after 1.5h of product use (C90) were significantly lower in the users of e-cigs than of Marlboro® cigarettes. The combination of glycerin and propylene glycol as the vehicle facilitated delivery of more nicotine than glycerin alone. The heart rate, systolic and diastolic blood pressure were significantly elevated after use of Marlboro® cigarettes, but the elevation was less after use of most of the e-cigs. Use of e-cigs had no impact on the exhaled CO levels, whereas the Marlboro® cigarette significantly increased the exhaled CO more than 8 times above the baseline. In conclusion, e-cigs could be a less harmful alternative for tobacco users. Copyright © 2014 Elsevier Inc. All rights reserved.

E-cigarette knowledge, attitudes, and use in opioid dependent smokers.

PubMed

Stein, Michael D; Caviness, Celeste M; Grimone, Kristin; Audet, Daniel; Borges, Allison; Anderson, Bradley J

2015-05-01

Individuals in treatment for opioid dependence have smoking rates 3-5 times greater than the U.S. prevalence rate. Traditional smoking cessation strategies have been ineffective in this population. Novel approaches are needed as well as harm reduction avenues. E-cigarettes (e-cigs) may provide such a novel harm reduction and cessation opportunity, but little is known about the knowledge of, attitudes about, and usage of e-cigs in opioid dependent smokers. The current study enrolled 315 opioid dependent smokers (164 methadone, 151 buprenorphine), treated in the same health system in Fall River, Massachusetts. The sample was 49.7% male and 85.1% non-Latino White. Overall 98.7% had heard of e-cigs, 73.0% had ever tried e-cigs, and 33.8% had used e-cigs in the past 30 days. The most common reasons for use were curiosity (41.4%) and to quit all nicotine (26.0%). The proportion of opioid dependent smokers that had ever tried e-cigs and used them in the past month was substantially greater than that found in recent general population surveys. While e-cigs have been used to quit smoking, how to optimize their utility as a cessation tool remains undefined. E-cigs should be a part of smoking cessation discussions with this vulnerable, difficult-to-treat population. Copyright © 2015 Elsevier Inc. All rights reserved.

Quenching Mo optical losses in CIGS solar cells by a point contacted dual-layer dielectric spacer: a 3-D optical study.

PubMed

Rezaei, Nasim; Isabella, Olindo; Vroon, Zeger; Zeman, Miro

2018-01-22

A 3-D optical modelling was calibrated to calculate the light absorption and the total reflection of fabricated CIGS solar cells. Absorption losses at molybdenum (Mo) / CIGS interface were explained in terms of plasmonic waves. To quench these losses, we assumed the insertion of a lossless dielectric spacer between Mo and CIGS, whose optical properties were varied. We show that such a spacer with low refractive index and proper thickness can significantly reduce absorption in Mo in the long wavelength regime and improve the device's rear reflectance, thus leading to enhanced light absorption in the CIGS layer. Therefore, we optimized a realistic two-layer MgF 2 / Al 2 O 3 dielectric spacer to exploit (i) the passivation properties of ultra-thin Al 2 O 3 on the CIGS side for potential high open-circuit voltage and (ii) the low refractive index of MgF 2 on the Mo side to reduce its optical losses. Combining our realistic spacer with optically-optimized point contacts increases the implied photocurrent density of a 750 nm-thick CIGS layer by 10% for the wavelengths between 700 and 1150 nm with respect to the reference cell. The elimination of plasmonic resonances in the new structure leads to a higher electric field magnitude at the bottom of CIGS layer and justifies the improved optical performance.

Factors associated with experimentation of electronic cigarettes among Parisian teenagers in 2013.

PubMed

Dautzenberg, Bertrand; Berlin, Ivan; Tanguy, Marie-Laure; Rieu, Nicole; Birkui, Pierre

2015-01-01

Electronic cigarettes (e-cig.) became widely used among adults. Data are insufficient about e-cig. experimentation among youth. To assess prevalence of e-cig. experimentation and associated factors among the 12 to 19 years old we analyse a cross sectional school based survey in the city of Paris, France in 2013 on a randomly selected sample of 2 % of schoolchildren (n = 3 279). Self-report questionnaire include demographic, individual and family smoking characteristics and questions about e-cig: "Have you ever used an e-cigarette?"- "Did you use e-cigarette in the last 30 days?"-"Did you try e-cigarette as a first tobacco product?". In 2013, 17.9 % (564) schoolchildren reported having experienced the e-cig (boys: 19.0 %, girls: 16.8 %) compared to 9.8 % in 2012. Experimentation rate increases from 5 % among the 12 to 30 % among the 16-year-old. E-cig. experimentation was significantly associated with 11 parameters including : age >15 years (OR: 0.66 (IC95 % = 0.46-0.94)); smoking 10 cigarettes or more (OR = 5.67 (IC95 % = 3.11-10.34)), best friends and siblings smoker (OR = 1.54 (IC95 % = 1.11-2.14)) and (OR = 1.88 (IC95 % = 1.41-2.52)); experimentation of shisha (OR = 2.60 (IC95 % = 1.75-3.86)), cannabis use (OR = 1.90 (IC95 % = 1.32-2.72)); having two parents who forbid smoking (OR = 2.32 (IC95 % = 1.63-3.30)). Only 5.6 % of the study population (and 32.5 % of e-cig. experimenters (183/564)) have used it in the last 30 days; 1.7 % of the study population and 10.0 % of e-cig. experimenters were non-smokers (56/564). Rate of e-cig. experimentation among schoolchildren increased by 8.1 % in 1 year. Non-smoking youth may use e-cig. Prospective studies are urgently needed to assess the evolution of e-cig. use both among smoking and non-smoking youth.

Driving Solar Innovations from Laboratory to Marketplace - Continuum

Science.gov Websites

. military-funded core technologies would someday lead to the internet. Or that a solar photovoltaics (PV more than a dozen start-up thin-film PV companies. This ultimately led to the creation of First Solar build a large-scale solar PV module plant in Colorado. As it has matured, CdTe technology has achieved

E-Cigs, Menthol & Dip

MedlinePlus

... are different. Find out why any product with nicotine can be addictive and bad for your health. What We Know About Electronic Cigarettes (E-cigarettes) Some people use e-cigs to quit smoking. But there is still much about e-cigs that's unknown. Read ...

Review of Artificial Abrasion Test Methods for PV Module Technology

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

Miller, David C.; Muller, Matt T.; Simpson, Lin J.

This review is intended to identify the method or methods--and the basic details of those methods--that might be used to develop an artificial abrasion test. Methods used in the PV literature were compared with their closest implementation in existing standards. Also, meetings of the International PV Quality Assurance Task Force Task Group 12-3 (TG12-3, which is concerned with coated glass) were used to identify established test methods. Feedback from the group, which included many of the authors from the PV literature, included insights not explored within the literature itself. The combined experience and examples from the literature are intended tomore » provide an assessment of the present industry practices and an informed path forward. Recommendations toward artificial abrasion test methods are then identified based on the experiences in the literature and feedback from the PV community. The review here is strictly focused on abrasion. Assessment methods, including optical performance (e.g., transmittance or reflectance), surface energy, and verification of chemical composition were not examined. Methods of artificially soiling PV modules or other specimens were not examined. The weathering of artificial or naturally soiled specimens (which may ultimately include combined temperature and humidity, thermal cycling and ultraviolet light) were also not examined. A sense of the purpose or application of an abrasion test method within the PV industry should, however, be evident from the literature.« less

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.

Differences between Dual Users and Switchers Center around Vaping Behavior and Its Experiences Rather than Beliefs and Attitudes

PubMed Central

2017-01-01

(1) Background: Many smokers completely switch to vaping (switchers), whereas others use e-cigarettes (e-cigs) alongside tobacco cigarettes (dual users). To the extent that dual users substantially lower the number of cigarettes, they will reduce health risks from smoking. However, from a medical point of view, exclusive vaping is preferable to dual use; (2) Methods: Using an online questionnaire we assessed behavioral, cognitive and attitudinal aspects of e-cig use in smoking and ex-smoking vapers; (3) Results: Our sample consisted of 19% dual users and 81% switchers. Before e-cig initiation, both groups smoked on average 22 cigarettes per day (CPD). After e-cig initiation, dual users decreased tobacco consumption by 82% and were low-to-moderately cigarette dependent. Both groups had been vaping for on average 22 months, were highly e-cig dependent, used state-of-the-art e-cigs, nicotine concentrations of 4–8 mg/mL and often flavors other than tobacco. Dual users used substantially less e-liquid per week than switchers but reported a similar number of puffs/day, experienced less e-cig efficacy, more practical problems, more negative and less positive consequences, and endorsed smoking reduction (rather than quitting) as a more important reason to start vaping. For both groups, e-cig risk perception was low and little stigmatization was experienced. Dual users preferred tobacco cigarettes in stressful situations and when rapid nicotine uptake is required. E-cigs were preferred where cigarettes are prohibited and to reduce second-hand smoke; (4) Conclusions: Differences between dual users and switchers center around variables proximal to the vaping behavior and its experienced effects rather than hinging on more general vaping-related beliefs and attitudes. PMID:29295483

Identification and Validation of Novel Hedgehog-Responsive Enhancers Predicted by Computational Analysis of Ci/Gli Binding Site Density

PubMed Central

Richards, Neil; Parker, David S.; Johnson, Lisa A.; Allen, Benjamin L.; Barolo, Scott; Gumucio, Deborah L.

2015-01-01

The Hedgehog (Hh) signaling pathway directs a multitude of cellular responses during embryogenesis and adult tissue homeostasis. Stimulation of the pathway results in activation of Hh target genes by the transcription factor Ci/Gli, which binds to specific motifs in genomic enhancers. In Drosophila, only a few enhancers (patched, decapentaplegic, wingless, stripe, knot, hairy, orthodenticle) have been shown by in vivo functional assays to depend on direct Ci/Gli regulation. All but one (orthodenticle) contain more than one Ci/Gli site, prompting us to directly test whether homotypic clustering of Ci/Gli binding sites is sufficient to define a Hh-regulated enhancer. We therefore developed a computational algorithm to identify Ci/Gli clusters that are enriched over random expectation, within a given region of the genome. Candidate genomic regions containing Ci/Gli clusters were functionally tested in chicken neural tube electroporation assays and in transgenic flies. Of the 22 Ci/Gli clusters tested, seven novel enhancers (and the previously known patched enhancer) were identified as Hh-responsive and Ci/Gli-dependent in one or both of these assays, including: Cuticular protein 100A (Cpr100A); invected (inv), which encodes an engrailed-related transcription factor expressed at the anterior/posterior wing disc boundary; roadkill (rdx), the fly homolog of vertebrate Spop; the segment polarity gene gooseberry (gsb); and two previously untested regions of the Hh receptor-encoding patched (ptc) gene. We conclude that homotypic Ci/Gli clustering is not sufficient information to ensure Hh-responsiveness; however, it can provide a clue for enhancer recognition within putative Hedgehog target gene loci. PMID:26710299

Differences between Dual Users and Switchers Center around Vaping Behavior and Its Experiences Rather than Beliefs and Attitudes.

PubMed

Adriaens, Karolien; Van Gucht, Dinska; Baeyens, Frank

2017-12-23

(1) Background: Many smokers completely switch to vaping (switchers), whereas others use e-cigarettes (e-cigs) alongside tobacco cigarettes (dual users). To the extent that dual users substantially lower the number of cigarettes, they will reduce health risks from smoking. However, from a medical point of view, exclusive vaping is preferable to dual use; (2) Methods: Using an online questionnaire we assessed behavioral, cognitive and attitudinal aspects of e-cig use in smoking and ex-smoking vapers; (3) Results: Our sample consisted of 19% dual users and 81% switchers. Before e-cig initiation, both groups smoked on average 22 cigarettes per day (CPD). After e-cig initiation, dual users decreased tobacco consumption by 82% and were low-to-moderately cigarette dependent. Both groups had been vaping for on average 22 months, were highly e-cig dependent, used state-of-the-art e-cigs, nicotine concentrations of 4-8 mg/mL and often flavors other than tobacco. Dual users used substantially less e-liquid per week than switchers but reported a similar number of puffs/day, experienced less e-cig efficacy, more practical problems, more negative and less positive consequences, and endorsed smoking reduction (rather than quitting) as a more important reason to start vaping. For both groups, e-cig risk perception was low and little stigmatization was experienced. Dual users preferred tobacco cigarettes in stressful situations and when rapid nicotine uptake is required. E-cigs were preferred where cigarettes are prohibited and to reduce second-hand smoke; (4) Conclusions: Differences between dual users and switchers center around variables proximal to the vaping behavior and its experienced effects rather than hinging on more general vaping-related beliefs and attitudes.

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.

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

Speer, B.; Mendelsohn, M.; Cory, K.

Insuring solar photovoltaic (PV) systems poses certain challenges. Insurance premiums, which can represent a significant part of overall costs for PV developers, can affect market competition. The market for certain types of insurance products is limited. Historical loss data is lacking, and test data for the long-term viability of PV products under real-life conditions is limited. Insurers' knowledge about PV systems and the PV industry is uneven even as the industry introduces innovative contractual structures and business models. Interviews conducted for this report with PV project developers, insurance brokers, and underwriters suggest government actions aimed at better testing, data collection,more » and communication could facilitate the development of a market for PV insurance products. This report identifies actions by governments, national laboratories, and other stakeholders that could accelerate the development of insurance products in support PV systems. Such actions include: increasing understanding of the solar PV industry among insurance professionals; expanding the availability of PV historical loss data; evaluating the expansion of renewable energy business classification; developing module and component testing capabilities and services offered by federal labs; and, advancing industry standards for PV system installers.« less

Intermediate Photovoltaic System Application Experiment. Oklahoma Center for Science and Arts. Phase II. Final report

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

Not Available

This report presents the key results of the Phase II efforts for the Intermediate PV System Applications Experiment at the Oklahoma Center for Science and Arts (OCSA). This phase of the project involved fabrication, installation and integration of a nominal 140 kW flat panel PV system made up of large, square polycrystalline-silicon solar cell modules, each nominally 61 cm x 122 cm in size. The output of the PV modules, supplied by Solarex Corporation, was augmented, 1.35 to 1 at peak, by a row of glass reflectors, appropriately tilted northward. The PV system interfaces with the Oklahoma Gas and Electricmore » Utility at the OCSA main switchgear. Any excess power generated by the system is fed into the utility under a one to one buyback arrangement. Except for a shortfall in the system output, presently suspected to be due to the poor performance of the modules, no serious problems were encountered. Certain value engineering changes implemented during construction and early operational failure events associated with the power conditioning system are also described. The system is currently undergoing extended testing and evaluation.« less

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In.... (6) Project Director means the individual responsible for the technical direction and management of...

Highly Automated Module Production Incorporating Advanced Light Management

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

Perelli-Minetti, Michael; Roof, Kyle

2015-08-11

The objective was to enable a high volume, cost effective solution for increasing the amount of light captured by PV modules through utilization of an advanced Light Re-directing Film and to follow a phased approach to develop and implement this new technology in order to achieve an expected power gain of up to 12 watts per module. Full size PV modules were manufactured using a new Light Redirecting Film (LRF) material applied to two different areas of PV modules in order to increase the amount of light captured by the modules. One configuration involved applying thin strips of LRF filmmore » over the tabbing ribbon on the cells in order to redirect the light that is normally absorbed by the tabbing ribbon to the active areas of the cells. A second configuration involved applying thin strips of LRF film over the white spaces between cells within a module in order to capture some of the light that is normally reflected from the white areas back through the front glass of the modules. Significant power increases of 1.4% (3.9 watts) and 1.0% (3.2 watts), respectively, compared to standard PV modules were measured under standard test conditions. The performance of PV modules with LRF applied to the tabbing ribbon was modeled. The results showed that the power increase provided by LRF depended greatly on the angle of incident light with the optimum performance only occurring when the light was within a narrow range of being perpendicular to the solar module. The modeling showed that most of the performance gain would be lost when the angle of incident light was greater than 28 degrees off axis. This effect made the orientation of modules with LRF applied to tabbing ribbons very important as modules mounted in “portrait” mode were predicted to provide little to no power gain from LRF under real world conditions. Based on these results, modules with LRF on tabbing ribbons would have to be mounted in “landscape” mode to realize a performance advantage. In addition, modeling showed that under diffuse lighting conditions such as when the sky is overcast, there would be no significant performance advantage for modules with LRF. Modules were sent to an outside contractor to measure the power performance under different angles of incident light in order to validate the modeling results. The measured data agreed very well with the modeling predictions and showed that the power gain for modules with LRF applied to tabbing ribbons was completely lost at an angle of 25 degrees off of perpendicular. At even larger angles, the power was lower than standard modules. From 35 degrees to 55 degrees off axis, the power loss was about 1.4% or equal to the power gain at the optimum condition of perfectly on-axis light.« less

High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

NASA Astrophysics Data System (ADS)

Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

2017-08-01

Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

Development of coring procedures applied to Si, CdTe, and CIGS solar panels

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

Moutinho, H. R.; Johnston, S.; To, B.

Most of the research on the performance and degradation of photovoltaic modules is based on macroscale measurements of device parameters such as efficiency, fill factor, open-circuit voltage, and short-circuit current. Our goal is to develop the capabilities to allow us to study the degradation of these parameters in the micro- and nanometer scale and to relate our results to performance parameters. To achieve this objective, the first step is to be able to access small samples from specific areas of the solar panels without changing the properties of the material. In this paper, we describe two coring procedures that wemore » developed and applied to Si, CIGS, and CdTe solar panels. In the first procedure, we cored full samples, whereas in the second we performed a partial coring that keeps the tempered glass intact. The cored samples were analyzed by different analytical techniques before and after coring, at the same locations, and no damage during the coring procedure was observed.« less

Development of coring procedures applied to Si, CdTe, and CIGS solar panels

DOE PAGES

Moutinho, H. R.; Johnston, S.; To, B.; ...

2018-01-04

Most of the research on the performance and degradation of photovoltaic modules is based on macroscale measurements of device parameters such as efficiency, fill factor, open-circuit voltage, and short-circuit current. Our goal is to develop the capabilities to allow us to study the degradation of these parameters in the micro- and nanometer scale and to relate our results to performance parameters. To achieve this objective, the first step is to be able to access small samples from specific areas of the solar panels without changing the properties of the material. In this paper, we describe two coring procedures that wemore » developed and applied to Si, CIGS, and CdTe solar panels. In the first procedure, we cored full samples, whereas in the second we performed a partial coring that keeps the tempered glass intact. The cored samples were analyzed by different analytical techniques before and after coring, at the same locations, and no damage during the coring procedure was observed.« less

Solar Photovoltaic DC Systems: Basics and Safety: Preprint

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

McNutt, Peter F; Sekulic, William R; Dreifuerst, Gary

Solar Photovoltaic (PV) systems are common and growing with 42.4 GW installed capacity in U.S. (almost 15 GW added in 2016). This paper will help electrical workers, and emergency responders understand the basic operating principles and hazards of PV DC arrays. We briefly discuss the following aspects of solar photovoltaic (PV) DC systems: the effects of solar radiation and temperature on output power; PV module testing standards; common system configurations; a simple PV array sizing example; NEC guidelines and other safety features; DC array commissioning, periodic maintenance and testing; arc-flash hazard potential; how electrical workers and emergency responders can andmore » do work safely around PV arrays; do moonlight and artificial lighting pose a real danger; typical safe operating procedures; and other potential DC-system hazards to be aware of. We also present some statistics on PV DC array electrical incidents and injuries. Safe PV array operation is possible with a good understanding of PV DC arrays basics and having good safe operating procedures in place.« less

The Effectiveness of Warranties in the Solar Photovoltaic and Automobile Industries

NASA Astrophysics Data System (ADS)

Formica, Tyler J.

A warranty is an agreement outlined by a manufacturer to a customer that defines performance requirements for a product or service. Although long warranty periods are a useful marketing tool, in 2011 the warranty claims expense was 2.6% of total sales for computer original equipment manufacturers (OEMs) and is over 2% of total sales in many other industries today. Solar PV systems offer inverters with 5-15 year warranties and PV modules with 25-year performance warranties. This is problematic for the return on investment (ROI) of solar PV systems when the modules are still productive and covered under warranty but inverter failures occur due to degradation of electronic components after their warranty has expired. Out-of-warranty inverter failures during the lifetime of solar panels decrease the ROI of solar PV systems significantly and can cause the annual ROI to actually be negative 15-25 years into the lifetime of the system. This thesis analyzes the factors that contribute to designing an optimal warranty period and the relationship between reliability and warranty periods using General Motors (GM) and the solar PV industry as case studies. A return on investment of a solar photovoltaic system is also conducted and the effect of reliability, changing tax credit structures, and failure areas of solar PV systems are analyzed.

The influence of different locations of sputter guns on the morphological and structural properties of Cu-In-Ga precursors and Cu(In,Ga)Se2 thin films

NASA Astrophysics Data System (ADS)

Wang, J.; Zhu, J.; He, Y. X.

2014-01-01

The influence of two different locations of sputter guns on the morphological and structural properties of Cu-In-Ga precursors and Cu(In,Ga)Se2 (CIGS) thin films was investigated. All the precursors contained cauliflower-like nodules, whereas smaller subnodules were observed on the background. All the precursors revealed apparent three-layered structures, and voids were observed at the CIGS/SLG interface of Sets 1 and 2 films rather than Set 3 film. EDS results indicated that all CIGS thin films were Cu-deficient. Based on the grazing incidence X-ray diffraction (GIXRD) patterns, as-selenized films showed peaks corresponding to the chalcopyrite-type CIGS structure. Depth-resolved Raman spectra showed the formation of a dominant CIGS phase inside the films for all the as-selenized samples investigated, and of an ordered vacancy compound (OVC) phase like Cu(In,Ga)3Se5 or Cu(In,Ga)2Se3.5 at the surface and/or CIGS/SLG interface region of Sets 2 and 3 films. No evidence was obtained on the presence of an OVC phase in Set 1 CIGS film, which may be speculated that long-time annealing is contributed to suppress the growth of OVC phases. The results of the present work suggest that the metallic precursors deposited with the upright-location sputter gun might be more appropriate to prepare CIGS thin films than those sputtered with the titled-location gun.

Origin of reduced efficiency in high Ga concentration Cu(In,Ga)Se2 solar cell

NASA Astrophysics Data System (ADS)

Wei, S.-H.; Huang, B.; Deng, H.; Contreras, M. A.; Noufi, R.; Chen, S.; Wang, L. W.

2014-03-01

CuInSe2 (CIS) is one of the most attractive thin-film materials for solar cells. It is well know that alloying Ga into CIS forming Cu(In,Ga)Se2 (CIGS) alloy is crucial to achieve the high efficiency, but adding too much Ga will lead to a decline of the solar cell efficiency. The exact origin of this puzzling phenomenon is currently still under debate. Using first-principles method, we have systemically studied the structural and electronic properties of CIGS alloys. Our phase diagram calculations suggest that increasing growth temperature may not be a critical factor in enhancing the cell performance of CIGS under equilibrium growth condition. On the other hand, our defect calculations identify that high concentration of antisite defects MCu(M =In, Ga) rather than anion defects are the key deep-trap centers in CIGS. The more the Ga concentration in CIGS, the more harmful the deep-trap is. Self-compensation in CIGS, which forms 2VCu + MCudefect complexes, is found to be beneficial to quench the deep-trap levels induced by MCu in CIGS, especially at low Ga concentration. Unfortunately, the density of isolated MCu is quite high and cannot be largely converted into 2VCu + MCu complexes under thermal equilibrium condition. Thus, nonequilibrium growth conditions or low growth temperature that can suppress the formation of the deep-trap centers MCu may be necessary for improving the efficiency of CIGS solar cells with high Ga concentrations.

Thin-Film Module Reverse-Bias Breakdown Sites Identified by Thermal Imaging: Preprint

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

Johnston, Steven; Sulas, Dana; Guthrey, Harvey L

Thin-film module sections are stressed under reverse bias to simulate partial shading conditions. Such stresses can cause permanent damage in the form of 'wormlike' defects due to thermal runaway. When large reverse biases with limited current are applied to the cells, dark lock-in thermography (DLIT) can detect where spatially-localized breakdown initiates before thermal runaway leads to permanent damage. Predicted breakdown defect sites have been identified in both CIGS and CdTe modules using DLIT. These defects include small pinholes, craters, or voids in the absorber layer of the film that lead to built-in areas of weakness where high current densities maymore » cause thermal damage in a partial-shading event.« less

Thin-Film Module Reverse-Bias Breakdown Sites Identified by Thermal Imaging

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

Johnston, Steven; Sulas, Dana; Guthrey, Harvey L

Thin-film module sections are stressed under reverse bias to simulate partial shading conditions. Such stresses can cause permanent damage in the form of 'wormlike' defects due to thermal runaway. When large reverse biases with limited current are applied to the cells, dark lock-in thermography (DLIT) can detect where spatially-localized breakdown initiates before thermal runaway leads to permanent damage. Predicted breakdown defect sites have been identified in both CIGS and CdTe modules using DLIT. These defects include small pinholes, craters, or voids in the absorber layer of the film that lead to built-in areas of weakness where high current densities maymore » cause thermal damage in a partial-shading event.« less

Energy performance of semi-transparent PV modules for applications in buildings

NASA Astrophysics Data System (ADS)

Fung, Yu Yan

Owing to the increasing awareness on energy conservation and environmental protection, building-integrated photovoltaic (BIPV) has been developed rapidly in the past decade. A number of research studies have been conducted on the energy performance of BIPV systems. However, most of the previous studies focused on the systems that incorporated with opaque type PV modules, little attention has been devoted to semi-transparent type PV modules, which have been commonly integrated in modern architectures. This thesis aims at evaluating the energy performance of the semi-transparent BIPV modules, including heat gains to the indoor environment, power generation from the PV modules and daylight utilization. Solar radiation intensity on PV module's surfaces is an essential parameter for assessing energy performance of the PV modules. Different slope solar radiation models are analyzed and compared. The model that best suits Hong Kong situations is selected for the further development of the energy performance of the BIPV modules. The optimum orientation and tilted angle are determined in the analysis. In addition to the solar radiation models, a detailed investigation on the heat gain through the semi-transparent BIPV modules is carried out in this study. A one-dimensional transient heat transfer model, the SPVHG model, for evaluating the thermal performance of the semi-transparent BIPV modules is developed. The SPVHG model considers in detail the energy that is transmitted, absorbed and reflected in each element of the BIPV modules such as solar cells and glass layers. A computer program of the model is written accordingly. By applying the SPVHG model, the heat gain through the semi-transparent BIPV module of any thickness can be determined for any solar irradiance level. The annual performance can also be assessed by inputting annual weather data to the model. In order to verify the SPVHG model, laboratory tests have been carried out on semi-transparent BIPV modules. A well-insulated calorimeter box and an adjustable steady-state type solar simulator which can provide up to 1600 W/m2 have been used in the tests. Energy that transmitted through the semi-transparent BIPV modules and entered the calorimeter box was evaluated. It was found that the experimental results and the simulated results support each other. The SPVHG model is validated and can be used for further studies. Other than heat transfer, power production and the daylight utilization are also the vital parts in the energy performance assessment of the semi-transparent BIPV module for applications in building facades. Power generation models of both opaque and semi-transparent BIPV modules are investigated in this study. In order to test the validity of the power generation model, measurements on a BIPV system of an existing building are carried out. The measurement results reveal a good validity of the power generation model. Only a minor modification to the model is required. The daylight utilization is evaluated by using an indoor illuminance model. The model estimates the mean internal illuminance on the working plane of a room when there is both sunlight and skylight. Consequently, the power saving due to the daylight utilization can be determined. By using the SPVHG model together with the power generation model and the indoor illuminance model, the energy performance, in terms of electricity benefit, of building facades that incorporated with semi-transparent BIPV modules is evaluated. Different scenarios are studied by changing various parameters such as the window to wall ratios, thickness and efficiency of the solar cells. The results show that the solar cells within the semi-transparent BIPV modules significantly reduce the solar heat gain and thus reduce the power consumption of air-conditioning systems. Taking into account the impacts of PV electricity generation and daylight utilization, the optimum solar cell area ratio in the PV modules varies from 0.7 to 0.9 for different window-to-wall ratios of the building facade. The largest net electricity benefit of the BIPV facade under the simulation conditions is around 120 kWh/m 2. The SPVHG model developed in this study is a precise model for calculating the amount of heat gains through the semi-transparent BIPV modules. By considering also the power generation and daylight utilization, the electricity benefit of different BIPV facade configurations can be simulated. This information should help engineers predict the cooling load due to the BIPV facade and thus review their designs for energy efficiency optimization. On the whole, the results of this study provide valuable reference to local engineers, designers and professionals for efficient BIPV facade applications.

Considerations for Solar Energy Technologies to Make Progress Towards Grid Price Parity

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

Woodhouse, Michael; Fu, Ran; Chung, Donald

2015-11-07

In this seminar the component costs for solar photovoltaics module and system prices will be highlighted. As a basis for comparison to other renewable and traditional energy options, the metric of focus will be total lifecycle cost-of-energy (LCOE). Several innovations to traditional photovoltaics technologies (including crystalline silicon, CdTe, and CIGS) and developing technologies (including organics and perovskites) that may close the gaps in LCOE will be discussed.

Extracellular matrix of collagen modulates arrhythmogenic activity of pulmonary veins through p38 MAPK activation.

PubMed

Lu, Yen-Yu; Chen, Yao-Chang; Kao, Yu-Hsun; Chen, Shih-Ann; Chen, Yi-Jen

2013-06-01

Atrial fibrillation (AF) is the most common sustained arrhythmia. Cardiac fibrosis with enhanced extracellular collagen plays a critical role in the pathophysiology of AF through structural and electrical remodeling. Pulmonary veins (PVs) are important foci for AF genesis. The purpose of this study was to evaluate whether collagen can directly modulate PV arrhythmogenesis. Action potentials and ionic currents were investigated in isolated male New Zealand rabbit PV cardiomyocytes with and without collagen incubation (10μg/ml, 5-7h) using the whole-cell patch-clamp technique. Compared to control PV cardiomyocytes (n=25), collagen-treated PV cardiomyocytes (n=22) had a faster beating rate (3.2±04 vs. 1.9±0.2Hz, p<0.005) and a larger amplitude of delayed afterdepolarization (16±2 vs. 10±1mV, p<0.01). Moreover, collagen-treated PV cardiomyocytes showed a larger transient outward potassium current, small-conductance Ca(2+)-activated K(+) current, inward rectifier potassium current, pacemaker current, and late sodium current than control PV cardiomyocytes, but amplitudes of the sodium current, sustained outward potassium current, and L-type calcium current were similar. Collagen increased the p38 MAPK phosphorylation in PV cardiomyocytes as compared to control. The change of the spontaneous activity and action potential morphology were ameliorated by SB203580 (the p38 MAPK catalytic activity inhibitor), indicating that collagen can directly increase PV cardiomyocyte arrhythmogenesis through p38 MAPK activation, which may contribute to the pathogenesis of AF. Copyright © 2013 Elsevier Ltd. All rights reserved.

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 10 2014-01-01 2014-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In... relationship is the transfer of a thing of value to a recipient in order to accomplish a public purpose of...

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 10 2012-01-01 2012-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In... relationship is the transfer of a thing of value to a recipient in order to accomplish a public purpose of...

7 CFR 1466.27 - Conservation Innovation Grants (CIG).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 10 2013-01-01 2013-01-01 false Conservation Innovation Grants (CIG). 1466.27 Section... PROGRAM Contracts and Payments § 1466.27 Conservation Innovation Grants (CIG). (a) Definitions. In... relationship is the transfer of a thing of value to a recipient in order to accomplish a public purpose of...

Reducing interface recombination for Cu(In,Ga)Se{sub 2} by atomic layer deposited buffer layers

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

Hultqvist, Adam; Bent, Stacey F.; Li, Jian V.

2015-07-20

Partial CuInGaSe{sub 2} (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnO{sub x} buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystallinemore » II–VI systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide.« less

Reducing interface recombination for Cu(In,Ga)Se 2 by atomic layer deposited buffer layers

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

Hultqvist, Adam; Li, Jian V.; Kuciauskas, Darius

2015-07-20

Partial CuInGaSe2 (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnOx buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystalline II-VImore » systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide.« less

Reducing interface recombination for Cu(In,Ga)Se 2 by atomic layer deposited buffer layers

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

Hultqvist, Adam; Li, Jian V.; Kuciauskas, Darius

2015-07-20

Partial CuInGaSe2 (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnOx buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystalline II–VImore » systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide.« less

Perceptions and use of electronic cigarettes in pregnancy

PubMed Central

McCubbin, Andrea; Fallin-Bennett, Amanda; Barnett, Janine; Ashford, Kristin

2017-01-01

Abstract Use of electronic cigarettes (e-cigs) is quickly growing in the United States, despite the unknown health implications and unregulated device contents. Although research is emerging around e-cigs in general, there continues to be a lack of scientific evidence regarding the safety and risks of e-cig use on maternal and fetal health, even though adverse health effects of nicotine on maternal and fetal outcomes are documented. This review summarizes existing perceptions of e-cig use in pregnancy, based on the limited number of publications available, and highlights the necessity of conducting additional research in this field of public health. Authors conducted a literature search of scientific peer-reviewed articles published from January 2006 to October 2016, comprising more than a decade of research. Search keywords include ‘tobacco use’, ‘electronic cigarette(s)’ and ‘pregnancy’. Fifty-seven publications were identified, narrowed to fifteen by screening title/abstract for potential relevance, with seven articles chosen for final inclusion. Of these seven studies, most participants not only believed e-cigs pose risks to maternal and child health but also perceived e-cigs as a safer and potentially healthier alternative to traditional cigarettes, and may assist with smoking cessation. Further research is needed to determine health implications and provide clinical guidelines for e-cig use in pregnancy. PMID:28158490

Air-annealing of Cu(In, Ga)Se2/CdS and performances of CIGS solar cells

NASA Astrophysics Data System (ADS)

Niu, X.; Zhu, H.; Liang, X.; Guo, Y.; Li, Z.; Mai, Y.

2017-12-01

In this study, the annealing treatment on Cu(In, Ga)Se2 (CIGS)/CdS interface in air is systematically investigated under different annealing temperatures from room temperature to 150 °C and different durations. It is found that when CIGS/CdS interface is annealed for a proper duration the corresponding CIGS thin film solar cells show enhanced open circuit voltage (Voc) and fill factor (FF) as well as corresponding conversion efficiency. The capacitance-voltage (C-V) and time-resolved photoluminescence (TR-PL) measurement results indicate that the CIGS thin film solar cells exhibit an increase in net defect density (NCV) and long lifetime for the carriers, respectively, after the annealing treatment of CIGS/CdS at a mediate annealing temperature here. Moreover, the net defect density of annealed solar cells at higher annealing temperatures for a long duration is reduced. All the variations in the solar cell performances, NCV and carrier lifetime would be related to the passivation of Se vacancies and InCu defects, surface (interface) states as well as positive interface discharges and Cu migration etc. A high efficiency CIGS solar cell of 14.4% is achieved. The optimized solar cell of 17.2% with a MgF2 anti-reflective layer has been obtained.

Electronic Cigarettes: Their Constituents and Potential Links to Asthma.

PubMed

Clapp, Phillip W; Jaspers, Ilona

2017-10-05

Vaping is gaining popularity in the USA, particularly among teens and young adults. While e-cigs are commonly represented as safer alternatives to tobacco cigarettes, little is known regarding the health effects of their short- or long-term use, especially in individuals with pre-existing respiratory diseases such as asthma. Flavored e-cig liquids (e-liquids) and e-cig aerosols contain airway irritants and toxicants that have been implicated in the pathogenesis and worsening of lung diseases. In this review, we will summarize existing data on potential health effects of components present in e-cig aerosols, such as propylene glycol, vegetable glycerin, nicotine, and flavorings, and discuss their relevance in the context of asthma. Recent survey data indicate that adolescents with asthma had a higher prevalence of current e-cig use (12.4%) compared to their non-asthmatics peers (10.2%) and conveyed positive beliefs about tobacco products, especially e-cigs. Similarly, a study conducted among high school students from Ontario, Canada, indicated a greater likelihood of e-cig use in asthmatics as compared to their non-asthmatic peers. Availability of different flavorings is often cited as the main reason among youth/adolescents for trying e-cigs or switching from cigarettes to e-cigs. Occupational inhalation of some common food-safe flavoring agents is reported to cause occupational asthma and worsen asthmatic symptoms. Moreover, workplace inhalation exposures to the flavoring agent diacetyl have caused irreversible obstructive airway disease in healthy workers. Additionally, recent studies report that thermal decomposition of propylene glycol (PG) and vegetable glycerin (VG), the base constituents of e-liquids, produces reactive carbonyls, including acrolein, formaldehyde, and acetaldehyde, which have known respiratory toxicities. Furthermore, recent nicotine studies in rodents reveal that prenatal nicotine exposures lead to epigenetic reprogramming in the offspring, abnormal lung development, and multigenerational transmission of asthmatic-like symptoms. Comparisons of the toxicity and health effects of e-cigs and conventional cigarettes often focus on toxicants known to be present in cigarette smoke (CS) (i.e., formaldehyde, nitrosamines, etc.), as well as smoking-associated clinical endpoints, such as cancer, bronchitis, and chronic obstructive pulmonary disease (COPD). However, this approach disregards potential toxicity of components unique to flavored e-cigs, such as PG, VG, and the many different flavoring chemicals, which likely induce respiratory effects not usually observed in cigarette smokers.

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

Marion, Bill; Smith, Benjamin

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. The method used back-solves for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the micro-inverter ac production data. When the derived values of DNI and DHI were then used to model the performance of other PV systems, the annual mean bias deviations were within +/- 4%, and only 1% greater than when the PV performance was modeled using high quality irradiance measurements. An uncertainty analysis showsmore » the method better suited for modeling PV performance than using satellite-based global horizontal irradiance.« less

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.

High Efficiency Solar Integrated Roof Membrane Product

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

Partyka, Eric; Shenoy, Anil

2013-05-15

This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

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

NASA Technical Reports Server (NTRS)

Nahra, Henry K.

1989-01-01

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

Effects of dust accumulation and module cleaning on performance ratio of solar rooftop system and solar power plants

NASA Astrophysics Data System (ADS)

Sakarapunthip, Nattakarn; Chenvidhya, Dhirayut; Chuangchote, Surawut; Kirtikara, Krissanapong; Chenvidhya, Tanokkorn; Onreabroy, Wandee

2017-08-01

Thailand is an agricultural country, with rice, sugar, and cassava as the major export products. Production of rice, sugar cane, and cassava entails agricultural activities that give rise to significant airborne dusts. In this work, five photovoltaic (PV) units (one solar rooftop and four power plants) are selected for the study. From the study of dust accumulation on glass surface located near rice farms, it was found that opaque areas due to the deposition of dust are 11-14% after 1-2-week exposure. As a consequence, PV system performance is affected. Performance ratio was calculated to determine these effects. Overall results reveal that during the dry and hot seasons, dust deposition significantly affects the performance ratio. The performance ratio reduces by 1.6-3% for 1-month dust accumulation and reduces by 6-8% for 2-month dust accumulation. After cleaning the dust accumulated, the performance ratio greatly increases, resulting in the increase in the energy output by 10%. This increase provides economic and cost benefits of PV cleaning. The performance ratio is not significantly changed during the rainy season, which PV modules are relatively clean as the dust is washed away by rain. It was also found that most of the solar power plants in Thailand still rely on manual cleaning of PV modules with washing water followed by wiping. However, only one power plant, employs a machine for cleaning, resulting in lower cleaning costs.

Automatic Fault Recognition of Photovoltaic Modules Based on Statistical Analysis of Uav Thermography

NASA Astrophysics Data System (ADS)

Kim, D.; Youn, J.; Kim, C.

2017-08-01

As a malfunctioning PV (Photovoltaic) cell has a higher temperature than adjacent normal cells, we can detect it easily with a thermal infrared sensor. However, it will be a time-consuming way to inspect large-scale PV power plants by a hand-held thermal infrared sensor. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule based on the mean intensity and standard deviation range was developed to detect defective PV modules from individual array automatically. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97 % or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule.

Power Management System Design for Solar-Powered UAS

DTIC Science & Technology

2015-12-01

PV cells would have their own MPPT modules, which would enable two major advantages. The first can be considered more important to land-based solar ...The efficiency of the PV array is represented by ηpv. R represents the solar irradiance, and θ represents the angle between the array and the sun...SYSTEM DESIGN FOR SOLAR -POWERED UAS by Robert T. Fauci III December 2015 Thesis Advisor: Alejandro Hernandez Co-Advisor: Kevin Jones

Wet Pretreatment-Induced Modification of Cu(In,Ga)Se2/Cd-Free ZnTiO Buffer Interface.

PubMed

Hwang, Suhwan; Larina, Liudmila; Lee, Hojin; Kim, Suncheul; Choi, Kyoung Soon; Jeon, Cheolho; Ahn, Byung Tae; Shin, Byungha

2018-06-20

We report a novel Cd-free ZnTiO buffer layer deposited by atomic layer deposition for Cu(In,Ga)Se 2 (CIGS) solar cells. Wet pretreatments of the CIGS absorbers with NH 4 OH, H 2 O, and/or aqueous solution of Cd 2+ ions were explored to improve the quality of the CIGS/ZnTiO interface, and their effects on the chemical state of the absorber and the final performance of Cd-free CIGS devices were investigated. X-ray photoelectron spectroscopy (XPS) analysis revealed that the aqueous solution etched away sodium compounds accumulated on the CIGS surface, which was found to be detrimental for solar cell operation. Wet treatment with NH 4 OH solution led to a reduced photocurrent, which was attributed to the thinning (or removal) of an ordered vacancy compound (OVC) layer on the CIGS surface as evidenced by an increased Cu XPS peak intensity after the NH 4 OH treatment. However, the addition of Cd 2+ ions to the NH 4 OH aqueous solution suppressed the etching of the OVC by NH 4 OH, explaining why such a negative effect of NH 4 OH is not present in the conventional chemical bath deposition of CdS. The band alignment at the CIGS/ZnTiO interface was quantified using XPS depth profile measurements. A small cliff-like conduction band offset of -0.11 eV was identified at the interface, which indicates room for further improvement of efficiency of the CIGS/ZnTiO solar cells once the band alignment is altered to a slight spike by inserting a passivation layer with a higher conduction band edge than ZnTiO. Combination of the small cliff conduction band offset at the interface, removal of the Na compound via water, and surface doping by Cd ions allowed the application of ZnTiO buffer to CIGS treated with Cd solutions, exhibiting an efficiency of 80% compared to that of a reference CIGS solar cell treated with the CdS.

PV Reliability -- Where We've Been and Where We're Going

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

Kurtz, Sarah

2017-04-27

The photovoltaic (PV) industry has demonstrated impressive progress toward deploying hardware with excellent quality. As module prices drop and designs are squeezed to reduce cost of materials and processing, how will this affect the failures that are seen in the field?

A grid-connected single-phase photovoltaic micro inverter

NASA Astrophysics Data System (ADS)

Wen, X. Y.; Lin, P. J.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.

2017-11-01

In this paper, the topology of a single-phase grid-connected photovoltaic (PV) micro-inverter is proposed. The PV micro-inverter consists of DC-DC stage with high voltage gain boost and DC-AC conversion stage. In the first stage, we apply the active clamp circuit and two voltage multipliers to achieve soft switching technology and high voltage gain. In addition, the flower pollination algorithm (FPA) is employed for the maximum power point tracking (MPPT) in the PV module in this stage. The second stage cascades a H-bridge inverter and LCL filter. To feed high quality sinusoidal power into the grid, the software phase lock, outer voltage loop and inner current loop control method are adopted as the control strategy. The performance of the proposed topology is tested by Matlab/Simulink. A PV module with maximum power 300W and maximum power point voltage 40V is applied as the input source. The simulation results indicate that the proposed topology and the control strategy are feasible.

Performance of double -pass solar collector with CPC and fins for heat transfer enhancement

NASA Astrophysics Data System (ADS)

Alfegi, Ebrahim M. A.; Abosbaia, Alhadi A. S.; Mezughi, Khaled M. A.; Sopian, Kamaruzzaman

2013-06-01

The temperature of photovoltaic modules increases when it absorbs solar radiation, causing a decrease in efficiency. This undesirable effect can be partially avoided by applying a heat recovery unit with fluid circulation (air or water) with the photovoltaic module. Such unit is called photovoltaic / thermal collector (pv/t) or hybrid (pv/t). In this unit, photovoltaic cells were pasted directly on the flat plate absorber. An experimental study of a solar air heater with photovoltaic cell located at the absorber with fins and compound parabolic collector for heat transfer enhancement and increasing the number of reflection on the cells have been conducted. The performance of the photovoltaic, thermal, and combined pv/t collector over range of operating conditions and the results was discussed. Results at solar irradiance of 500 W/m2 show that the combined pv/t efficiency is increasing from 37.28 % to 81.41 % at mass flow rates various from 0.029 to 0.436 kg/s.

Successful Nicotine Intake in Medical Assisted Use of E-Cigarettes: A Pilot Study

PubMed Central

Pacifici, Roberta; Pichini, Simona; Graziano, Silvia; Pellegrini, Manuela; Massaro, Giuseppina; Beatrice, Fabio

2015-01-01

The electronic cigarette (e-cig) has gained popularity as an aid in smoking cessation programs mainly because it maintains the gestures and rituals of tobacco smoking. However, it has been shown in inexperienced e-cig users that ineffective nicotine delivery can cause tobacco craving that could be responsible for unsuccessful smoking reduction/cessation. Moreover, the incorrect use of an e-cig could also led to potential nicotine overdosage and intoxication. Medically assisted training on the proper use of an e-cig plus behavioral support for tobacco dependence could be a pivotal step in avoiding both issues. We performed an eight-month pilot study of adult smokers who started e-cig use after receiving a multi-component medically assisted training program with monitoring of nicotine intake as a biomarker of correct e-cig use. Participants were tested during follow-up for breath carbon monoxide (CO), plasma cotinine and trans-3’-hydroxycotinine, and number of tobacco cigarettes smoked. At the end of the first, fourth, and eighth month of follow-up, 91.1, 73.5, and 76.5% of participants respectively were e-cig users (‘only e-cig’ and ‘dual users’). They showed no significant variation in plasma cotinine and trans-3’-hydroxycotinine with respect to the start of the study when they smoked only tobacco cigarettes, but a significant reduction in breath CO. The proposed medically assisted training program of e-cig use led to a successful nicotine intake, lack of typical cigarette craving and overdosage symptoms and a significant decrease in the biomarker of cigarette combustion products. PMID:26184244

Effect of yoghurt or yoghurt serum on microbial quality of cig kofte.

PubMed

Dogan, Mahmut; Cankurt, Hasan; Toker, Omer Said; Yetim, Hasan; Sagdic, Osman

2014-07-01

Cig kofte, raw meatball is a traditionally produced meat product in Turkey and some other Middle East countries. It is prepared from mixtures of finely minced raw beef, bulgur, onions, various spices and tap water. Cig kofte is an uncooked product and popularly consumed with lettuce and lemon juice. In this study, yoghurt or yoghurt serum (YS) were added to the mixtures of cig kofte instead of tap water to reduce microbial risks of the raw meatball. Additionally, the effects of yoghurt and YS on some physicochemical characteristics of cig kofte were investigated. Cig kofte is generally consumed within a few hours after the preparation because of its raw nature. Also, it is generally sold under unhygienic conditions in restaurants and restaurant-like places. For this purpose, reducing of the microbial load of cig kofte is important. In the results, Escherichia coli and Listeria monocytogenes were not detected in any samples. While lactic acid bacteria count increased by addition of yoghurt and YS, the number of other microorganisms except for total aerobic mesophilic bacteria (TAMB) were decreased. The aw values and% moisture contents of the samples were varied between 0.88-0.94 and 46.25-49.72, respectively. The pH values of the samples were slightly changed during the storage of 24 h while no changes detected in the control samples during the storage. In conclusion, it can be suggested that using the yoghurt or YS instead of tap water in the preparation of cig kofte might ensure the microbial safety, increase the nutritional value and its flavour or aroma.

Outlook and Challenges of Perovskite Solar Cells toward Terawatt-Scale Photovoltaic Module Technology

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

Zhu, Kai; Kim, Donghoe; Whitaker, James B

Rapid development of perovskite solar cells (PSCs) during the past several years has made this photovoltaic (PV) technology a serious contender for potential large-scale deployment on the terawatt scale in the PV market. To successfully transition PSC technology from the laboratory to industry scale, substantial efforts need to focus on scalable fabrication of high-performance perovskite modules with minimum negative environmental impact. Here, we provide an overview of the current research and our perspective regarding PSC technology toward future large-scale manufacturing and deployment. Several key challenges discussed are (1) a scalable process for large-area perovskite module fabrication; (2) less hazardous chemicalmore » routes for PSC fabrication; and (3) suitable perovskite module designs for different applications.« less

Correlation between surface carbon concentration and adhesive strength at the Si cell/EVA interface in a PV module

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

Dhere, N.G.; Wollam, M.E.; Gadre, K.S.

1997-12-31

Silicon solar cell/EVA composite is being studied with an objective to further improve the manufacturing technology of PV modules. Sample extraction and adhesion strength measurement process has been modified. Silicon and EVA samples were extracted from solar cells of new and field-deployed modules. Optical microscopy, SEM, and AES of samples from new modules revealed EVA islands covering most of the silicon cell surface indicating a cohesive failure. A good correlation was observed between the adhesive strength and surface concentration of carbon. A low carbon concentration which indicated less EVA clinging to cell surface always resulted in low adhesive strengths. Themore » correlation provides a simple technique for inferring properties of EVA.« less

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

Lave, Matthew Samuel; Stein, Joshua; Burnham, Laurie

This report provides performance data and analysis for two Stion copper indium gallium selenide (CIGS) module types, one framed, the other frameless, and installed at the New Mexico, Florida and Vermont RTCs. Sandia looked at data from both module types and compared the latter with data from an adjacent monocrystalline baseline array at each RTC. The results indicate that the Stion modules are slightly outperforming their rated power, with efficiency values above 100% of rated power, at 25degC cell temperatures. In addition, Sandia sees no significant performance differences between module types, which is expected because the modules differ only inmore » their framing. In contrast to the baseline systems, the Stion strings showed increasing efficiency with increasing irradiance, with the greatest increase between zero and 400 Wm -2 but still noticeable increases at 1000 Wm -2 . Although baseline data availability in Vermont was spotty and therefore comparative trends are difficult to discern, the Stion modules there may offer snow- shedding advantages over monocrystalline-silicon modules but these findings are preliminary.« less

Determination of the Electrical Junction in Cu(In, Ga)Se2 and Cu2ZnSnSe4 Solar Cells with 20-nm Spatial Resolution

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

Xiao, Chuanxiao; Jiang, Chun-Sheng; Moutinho, Helio

2016-11-21

We located the electrical junction (EJ) of Cu(In, Ga)Se2 (CIGS) and Cu2ZnSnSe4 (CZTS) solar cells with ~20-nm accuracy using a scanning capacitance spectroscopy (SCS) technique. A procedure was developed to prepare the cross-sectional samples and grow critical high-quality insulating layers for the SCS measurement. We found that CIGS has a buried homojunction with the EJ located at ~40 nm inside the CIGS/CdS interface. An n-type CIGS was probed in the region 10-30 nm away from the interface. By contrast, the CZTS/CdS cells have a heterointerface junction with a shallower EJ (~20 nm) than CIGS. The EJ is ~20 nm frommore » the CZTS/CdS interface, which is consistent with asymmetrical carrier concentrations of the p-CZTS and n-CdS in a heterojunction cell. The unambiguous determination of the junction locations helped explain the large open circuit voltage difference between the state-of-the-art devices of CIGS and CZTS.« less

Resource recovery from urban stock, the example of cadmium and tellurium from thin film module recycling.

PubMed

Simon, F-G; Holm, O; Berger, W

2013-04-01

Raw material supply is essential for all industrial activities. The use of secondary raw material gains more importance since ore grade in primary production is decreasing. Meanwhile urban stock contains considerable amounts of various elements. Photovoltaic (PV) generating systems are part of the urban stock and recycling technologies for PV thin film modules with CdTe as semiconductor are needed because cadmium could cause hazardous environmental impact and tellurium is a scarce element where future supply might be constrained. The paper describes a sequence of mechanical processing techniques for end-of-life PV thin film modules consisting of sandblasting and flotation. Separation of the semiconductor material from the glass surface was possible, however, enrichment and yield of valuables in the flotation step were non-satisfying. Nevertheless, recovery of valuable metals from urban stock is a viable method for the extension of the availability of limited natural resources. Copyright © 2013 Elsevier Ltd. All rights reserved.

Knowledge on Irradiation, Medical Imaging Prescriptions, and Clinical Imaging Referral Guidelines among Physicians in a Sub-Saharan African Country (Cameroon)

PubMed Central

Tene, Ulrich; Samba Ngano, Odette; Tchemtchoua Youta, Justine; Simo, Augustin; Gonsu Fotsin, Joseph

2017-01-01

Background Clinical imaging guidelines (CIGs) are suitable tools to enhance justification of imaging procedures. Objective To assess physicians' knowledge on irradiation, their self-perception of imaging prescriptions, and the use of CIGs. Materials and Methods A questionnaire of 21 items was self-administered between July and August 2016 to 155 referring physicians working in seven university-affiliated hospitals in Yaoundé and Douala (Cameroon). This pretested questionnaire based on imaging referral practices, the use and the need of CIGs, knowledge on radiation doses of 11 specific radiologic procedures, and knowledge of injurious effects of radiation was completed in the presence of the investigator. Scores were allocated for each question. Results 155 questionnaires were completed out of 180 administered (86.1%). Participants were 90 (58%) females, 63 (40.64%) specialists, 53 (34.20%) residents/interns, and 39 (25.16%) general practitioners. The average professional experience was 7.4 years (1–25 years). The mean knowledge score was 11.5/59 with no influence of sex, years of experience, and professional category. CIGs users' score was better than nonusers (means 14.2 versus 10.6; p < 0.01). 80% of physicians (124/155) underrated radiation doses of routine imaging exams. Seventy-eight (50.3%) participants have knowledge on CIGs and half of them made use of them. “Impact on diagnosis” was the highest justification criteria follow by “impact on treatment decision.” Unjustified requests were mainly for “patient expectation or will” or for “research motivations.” 96% of interviewees believed that making available national CIGs will improve justification. Conclusion Most physicians did not have appropriate awareness about radiation doses for routine imaging procedures. A small number of physicians have knowledge on CIGs but they believe that making available CIGs will improve justification of imaging procedures. Continuous trainings on radiation protection and implementation of national CIGs are therefore recommended. PMID:28630770

Materials and Chemical Science and Technology | Research | NREL

Science.gov Websites

Applications and Performance Developing high-efficiency crystalline PV, measuring PV cell/module performance Cells and Hydrogen Program Developing, integrating, and demonstrating hydrogen production/delivery /storage through core programs and EFRCs Point of Contact Bill Tumas MCST Research Advisors/Fellows Senior

Chris Deline | NREL

Science.gov Websites

., Meydbray, J., Donovan, M., and Forrest, J. 2014. Photovoltaic Shading Testbed for Module-Level Power Renewable Energy Laboratory (NREL) in Golden, Colorado, in the photovoltaic (PV) performance and reliability performance and stabilization, mismatch and partial shading in PV systems, and distributed power electronics

Indiana | Solar Research | NREL

Science.gov Websites

Incentive Programs Indiana exempts solar PV modules, racking, and inverter from state sales and use taxes . The entire solar generating system is exempt from property taxation. Utility Incentive Programs Utility Incentive Limitations Northern Indiana Public Service Company (Solar PV feed-in-tariff) $0.1564

Cost Benefit Analysis of Integrated COTS Energy- Related Technologies for Army’s Force Provider Module

DTIC Science & Technology

2009-09-01

Year Defense Plan (FYDP), on which the Department of Defense operates, subsequently needs 26 Richard G. Lugar, U.S. Senator for Indiana , “U.S...mature thin-film technologies exist such as Amorphous Silicon (a-Si), Cadmium Telluride (CdTe), and Copper Indium Gallium (di) Selenide (CIGS), all...cheaper processing, lower material costs, and is free of the environmental and health hazard issues of cadmium . Amorphous silicon coupled with

Characterization of a low concentrator photovoltaics module

NASA Astrophysics Data System (ADS)

Butler, B. A.; van Dyk, E. E.; Vorster, F. J.; Okullo, W.; Munji, M. K.; Booysen, P.

2012-05-01

Low concentration photovoltaic (LCPV) systems have the potential to reduce the cost per kWh of electricity compared to conventional flat-plate photovoltaics (PV) by up to 50%. The cost-savings are realised by replacing expensive PV cells with relatively cheaper optical components to concentrate incident solar irradiance onto a receiver and by tracking the sun along either 1 axis or 2 axes. A LCPV module consists of three interrelated subsystems, viz., the optical, electrical and the thermal subsystems, which must be considered for optimal module design and performance. Successful integration of these subsystems requires the balancing of cost, performance and reliability. In this study LCPV experimental prototype modules were designed, built and evaluated with respect to optimisation of the three subsystems and overall performance. This paper reports on the optical and electrical evaluation of a prototype LCPV module.

Partial Shade Stress Test for Thin-Film Photovoltaic Modules: Preprint

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

Silverman, Timothy J.; Deceglie, Michael G.; Deline, Chris

2015-09-02

Partial shade of monolithic thin-film PV modules can cause reverse-bias conditions leading to permanent damage. In this work, we propose a partial shade stress test for thin-film PV modules that quantifies permanent performance loss. We designed the test with the aid of a computer model that predicts the local voltage, current and temperature stress that result from partial shade. The model predicts the module-scale interactions among the illumination pattern, the electrical properties of the photovoltaic material and the thermal properties of the module package. The test reproduces shading and loading conditions that may occur in the field. It accounts formore » reversible light-induced performance changes and for additional stress that may be introduced by light-enhanced reverse breakdown. We present simulated and experimental results from the application of the proposed test.« less

Characterization of Cu(In,Ga)Se 2 (CIGS) films with varying gallium ratios

DOE PAGES

Claypoole, Jesse; Peace, Bernadette; Sun, Neville; ...

2015-09-05

Cu(In 1–x,Ga x)Se 2 (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In + Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In + Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. Themore » Ga grading in the CIGS layer has the effect causing a higher band gap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In + Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In + Ga) ratios. Moreover, it was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In + Ga) ratios. Furthermore, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.« less

Immunological and toxicological risk assessment of e-cigarettes.

PubMed

Kaur, Gagandeep; Pinkston, Rakeysha; Mclemore, Benathel; Dorsey, Waneene C; Batra, Sanjay

2018-03-31

Knowledge of the long-term toxicological and immunological effects of e-cigarette (e-cig) aerosols remains elusive due to the relatively short existence of vaping. Therefore, we performed a systematic search of articles published in public databases and analysed the research evidence in order to provide critical information regarding e-cig safety. Electronic nicotine delivery systems (or e-cigs) are an alternative to traditional cigarettes for the delivery of nicotine and are typically filled with glycerol or propylene glycol-based solutions known as e-liquids. Though present in lower quantities, e-cig aerosols are known to contain many of the harmful chemicals found in tobacco smoke. However, due to the paucity of experimental data and contradictory evidence, it is difficult to draw conclusive outcomes regarding toxicological, immunological and clinical impacts of e-cig aerosols. Excessive vaping has been reported to induce inflammatory responses including mitogen-activated protein kinase, Janus tyrosine kinase/signal transducer and activator of transcription and nuclear factor-κB signalling, similar to that induced by tobacco smoke. Based on recent evidence, prolonged exposure to some constituents of e-cig aerosols might result in respiratory complications such as asthma, chronic obstructive pulmonary disease and inflammation. Future studies are warranted that focus on establishing correlations between e-cig types, generations and e-liquid flavours and immunological and toxicological profiles to broaden our understanding about the effects of vaping. Copyright ©ERS 2018.

A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation.

PubMed

Shields, Peter G; Berman, Micah; Brasky, Theodore M; Freudenheim, Jo L; Mathe, Ewy; McElroy, Joseph P; Song, Min-Ae; Wewers, Mark D

2017-08-01

The use of electronic cigarettes (e-cigs) is increasing rapidly, but their effects on lung toxicity are largely unknown. Smoking is a well-established cause of lung cancer and respiratory disease, in part through inflammation. It is plausible that e-cig use might affect similar inflammatory pathways. E-cigs are used by some smokers as an aid for quitting or smoking reduction, and by never smokers (e.g., adolescents and young adults). The relative effects for impacting disease risk may differ for these groups. Cell culture and experimental animal data indicate that e-cigs have the potential for inducing inflammation, albeit much less than smoking. Human studies show that e-cig use in smokers is associated with substantial reductions in blood or urinary biomarkers of tobacco toxicants when completely switching and somewhat for dual use. However, the extent to which these biomarkers are surrogates for potential lung toxicity remains unclear. The FDA now has regulatory authority over e-cigs and can regulate product and e-liquid design features, such as nicotine content and delivery, voltage, e-liquid formulations, and flavors. All of these factors may impact pulmonary toxicity. This review summarizes current data on pulmonary inflammation related to both smoking and e-cig use, with a focus on human lung biomarkers. Cancer Epidemiol Biomarkers Prev; 26(8); 1175-91. ©2017 AACR . ©2017 American Association for Cancer Research.

Solar-powered unmanned aerial vehicles

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

Reinhardt, K.C.; Lamp, T.R.; Geis, J.W.

1996-12-31

An analysis was performed to determine the impact of various power system components and mission requirements on the size of solar-powered high altitude long endurance (HALE)-type aircraft. The HALE unmanned aerial vehicle (UAV) has good potential for use in many military and civil applications. The primary power system components considered in this study were photovoltaic (PV) modules for power generation and regenerative fuel cells for energy storage. The impact of relevant component performance on UAV size and capability were considered; including PV module efficiency and mass, power electronics efficiency, and fuel cell specific energy. Mission parameters such as time ofmore » year, flight altitude, flight latitude, and payload mass and power were also varied to determine impact on UAV size. The aircraft analysis method used determines the required aircraft wing aspect ratio, wing area, and total mass based on maximum endurance or minimum required power calculations. The results indicate that the capacity of the energy storage system employed, fuel cells in this analysis, greatly impacts aircraft size, whereas the impact of PV module efficiency and mass is much less important. It was concluded that an energy storage specific energy (total system) of 250--500 Whr/kg is required to enable most useful missions, and that PV cells with efficiencies greater than {approximately} 12% are suitable for use.« less

A sunny future: expert elicitation of China's solar photovoltaic technologies

NASA Astrophysics Data System (ADS)

Lam, Long T.; Branstetter, Lee; Azevedo, Inês L.

2018-03-01

China has emerged as the global manufacturing center for solar photovoltaic (PV) products. Chinese firms have entered all stages of the supply chain, producing most of the installed solar modules around the world. Meanwhile, production costs are at record lows. The decisions that Chinese solar producers make today will influence the path for the solar industry and its role towards de-carbonization of global energy systems in the years to come. However, to date, there have been no assessments of the future costs and efficiency of solar PV systems produced by the Chinese PV industry. We perform an expert elicitation to assess the technological and non-technological factors that led to the success of China’s silicon PV industry as well as likely future costs and performance. Experts evaluated key metrics such as efficiency, costs, and commercial viability of 17 silicon and non-silicon solar PV technologies by 2030. Silicon-based technologies will continue to be the mainstream product for large-scale electricity generation application in the near future, with module efficiency reaching as high as 23% and production cost as low as 0.24/W. The levelized cost of electricity for solar will be around 34/MWh, allowing solar PV to be competitive with traditional energy resources like coal. The industry’s future developments may be affected by overinvestment, overcapacity, and singular short-term focus.

A pulse-width modulated, high reliability charge controller for small photovoltaic systems

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

Gerken, K.; Welsh, D.

1997-02-01

This report presents the results of a development effort to design, test and begin production of a new class of small photovoltaic (PV) charge controllers. Sandia National Laboratories provided technical support, test data and financial support through a Balance-of-System Development contract. One of the objectives of the development was to increase user confidence in small PV systems by improving the reliability and operating life of the system controllers. Another equally important objective was to improve the economics of small PV systems by extending the battery lifetimes. Using new technology and advanced manufacturing techniques, these objectives were accomplished. Because small stand-alonemore » PV systems account for over one third of all PV modules shipped, the positive impact of improving the reliability and economics of PV systems in this market segment will be felt throughout the industry. The results of verification testing of the new product are also included in this report. The initial design goals and specifications were very aggressive, but the extensive testing demonstrates that all the goals were achieved. Production of the product started in May at a rate of 2,000 units per month. Over 40 Morningstar distributors (5 US and 35 overseas) have taken delivery in the first 2 months of shipments. Initial customer reactions to the new controller have been very favorable.« less

Perceptions and Use of Electronic Cigarettes in Pregnancy

ERIC Educational Resources Information Center

McCubbin, Andrea; Fallin-Bennett, Amanda; Barnett, Janine; Ashford, Kristin

2017-01-01

Use of electronic cigarettes (e-cigs) is quickly growing in the United States, despite the unknown health implications and unregulated device contents. Although research is emerging around e-cigs in general, there continues to be a lack of scientific evidence regarding the safety and risks of e-cig use on maternal and fetal health, even though…

Analysis of comments in a petition defending electronic cigarettes.

PubMed

Sumner, Holly Marie; McQueen, Amy; Scott, Michael John; Sumner, Walton

2014-11-01

A 2009 petition opposing a Food and Drug Administration (FDA) ban on electronic cigarettes (e-cigs) garnered international attention from e-cig users (vapers). Petitioners' comments described the perceived benefits of vaping. We conducted a qualitative and quantitative analysis of petitioners' comments. A sample of 200 petitioner names was sought in public records. Reviewers identified 13 major themes in a sample of comments, and themes related to current controversies were added. For each theme, software pattern-matching instructions (regular expressions) were developed and were used to scan comments. Agreement between reviewers and software was calculated; theme prevalence and clustering was ascertained. A total of 13,414 signatures and 8,285 comments from 50 states and 75 nations were collected in 6 months. Temporal patterns and name matches in public records suggest that most petitioners are authentic. Agreement between reviewers and software was moderate to high (κ = 0.4-0.8). Commonly cited themes were "e-cigs helped me quit" (34%), "a ban would be counterproductive" (15%), and "my health improved with e-cigs" (13%). Two clusters of themes emerged: the first combined comments about smoking cessation, health benefits, and smoking relapse that an e-cig ban would cause; the second combined themes that a "ban would be counterproductive," it would infringe on personal liberties, and it was motivated by government or industrial greed. People who cited mental health issues often mentioned avoiding withdrawal as a benefit of e-cigs. Early e-cig adopters were both frustrated and confused by discussion of a ban. They believed that e-cigs safely delivered nicotine and helped them quit smoking. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Electronic cigarette: a threat or an opportunity for public health? State of the art and future perspectives.

PubMed

Protano, C; Di Milia, L M; Orsi, G B; Vitali, M

2015-01-01

The e-cigarette, also known as e-cig, represents an emerging issue of great concern for public health. The aim of the present report was to explore the scientific literature about the use of electronic cigarette (e-cig), with a particular reference to the features of "toxicological safety", "effectiveness in overcoming the addiction to smoking the traditional cigarette" and "necessary research agenda". The efficacy of e-cig for smoking cessation is uncertain: some authors found that it can be a valid support, but long-term cessation rate has not be assessed. Other studies evidenced that e-cig is often used not for quitting smoking but to avoid smoking ban for traditional cigarettes and, even, some researches evidenced that it appears to contribute to nicotine addiction. E-cig smoking seems to be less dangerous of conventional cigarettes, but its use is not risk-free. Besides, cases of accidental or intentional poisoning with liquid solutions of e-cig have been reported. Also, the smoke of e-cig decreases indoor air quality, releasing particulate matter and other toxics that can persist on surfaces for days and generating passive exposure. These phenomena are similar to environmental tobacco smoke produced by conventional smoking, that is the sum of second- and third-hand smoke. We propose to call them "environmental electronic smoke", "electronic-second- hand smoke" and "electronic-third-hand smoke", respectively. Uncertainties relating to e-cig features determined the sequence, in the short term, of warnings and regulations approved and then replaced. In conclusion, although in recent years many researches were performed, evidences is limited and there is a need to study in deep all these issues.

Protective Effects of Cornel Iridoid Glycoside in Rats After Traumatic Brain Injury.

PubMed

Ma, Denglei; Wang, Na; Fan, Xiaotong; Zhang, Lan; Luo, Yi; Huang, Rui; Zhang, Li; Li, Yali; Zhao, Guoguang; Li, Lin

2018-04-01

Cornel iridoid glycoside (CIG) is the active ingredient extracted from Cornus officinalis. Our previous studies showed that CIG had protective effects on several brain injury models. In the present study, we aimed to examine the effects and elucidate the mechanisms of CIG against traumatic brain injury (TBI). TBI was induced in the right cerebral cortex of male adult rats. The neurological and cognitive functions were evaluated by modified neurological severity score (mNSS) and object recognition test (ORT), respectively. The level of serum S100β was measured by an ELISA method. Nissl staining was used to estimate the neuron survival in the brain. The expression of proteins was determined by western blot and/or immunohistochemical staining. We found that intragastric administration of CIG in TBI rats ameliorated the neurological defects and cognitive impairment, and alleviated the neuronal loss in the injured brain. In the acute stage of TBI (24-72 h), CIG decreased the level of S100β in the serum and brain, increased the ratio of Bcl-2/Bax and decreased the expression of caspase-3 in the injured cortex. Moreover, the treatment with CIG for 30 days increased the levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), enhanced the expression of synapsin I, synaptophysin and postsynaptic density protein 95 (PSD-95), and inhibited the apoptosis-regulating factors in the chronic stage of TBI. The present study demonstrated that CIG had neuroprotective effects against TBI through inhibiting apoptosis in the acute stage and promoting neurorestoration in the chronic stage. The results suggest that CIG may be beneficial to TBI therapy.

Device Performance | Photovoltaic Research | NREL

Science.gov Websites

Device Performance Device Performance PV Calibrations Blog Check out the latest updates from the PV than 190 person-years. Capabilities Our capabilities for measuring key performance parameters of solar cells and modules include the use of various solar simulators and tools to measure current-voltage and

Module Embedded Micro-inverter Smart Grid Ready Residential Solar Electric System

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

Agamy, Mohammed

The “Module Embedded Micro-inverter Smart Grid Ready Residential Solar Electric System” program is focused on developing innovative concepts for residential photovoltaic (PV) systems with the following objectives: to create an Innovative micro-inverter topology that reduces the cost from the best in class micro-inverter and provides high efficiency (>96% CEC - California Energy Commission), and 25+ year warranty, as well as reactive power support; integrate micro-inverter and PV module to reduce system price by at least $0.25/W through a) accentuating dual use of the module metal frame as a large area heat spreader reducing operating temperature, and b) eliminating redundant wiringmore » and connectors; and create micro-inverter controller handles smart grid and safety functions to simplify implementation and reduce cost.« less

Measured and estimated performance of a fleet of shaded photovoltaic systems with string and module-level inverters

DOE PAGES

MacAlpine, Sara; Deline, Chris; Dobos, Aron

2017-03-16

Shade obstructions can significantly impact the performance of photovoltaic (PV) systems. Although there are many models for partially shaded PV arrays, there is a lack of information available regarding their accuracy and uncertainty when compared with actual field performance. This work assesses the recorded performance of 46 residential PV systems, equipped with either string-level or module-level inverters, under a variety of shading conditions. We compare their energy production data to annual PV performance predictions, with a focus on the practical models developed here for National Renewable Energy Laboratory's system advisor model software. This includes assessment of shade extent on eachmore » PV system by using traditional onsite surveys and newer 3D obstruction modelling. The electrical impact of shade is modelled by either a nonlinear performance model or assumption of linear impact with shade extent, depending on the inverter type. When applied to the fleet of residential PV systems, performance is predicted with median annual bias errors of 2.5% or less, for systems with up to 20% estimated shading loss. The partial shade models are not found to add appreciable uncertainty to annual predictions of energy production for this fleet of systems but do introduce a monthly root-mean-square error of approximately 4%-9% due to seasonal effects. Here the use of a detailed 3D model results in similar or improved accuracy over site survey methods, indicating that, with proper description of shade obstructions, modelling of partially shaded PV arrays can be done completely remotely, potentially saving time and cost.« less

Comparative alternative materials assessment to screen toxicity hazards in the life cycle of CIGS thin film photovoltaics.

PubMed

Eisenberg, Daniel A; Yu, Mengjing; Lam, Carl W; Ogunseitan, Oladele A; Schoenung, Julie M

2013-09-15

Copper-indium-gallium-selenium-sulfide (CIGS) thin film photovoltaics are increasingly penetrating the market supply for consumer solar panels. Although CIGS is attractive for producing less greenhouse gas emissions than fossil-fuel based energy sources, CIGS manufacturing processes and solar cell devices use hazardous materials that should be carefully considered in evaluating and comparing net environmental benefits of energy products. Through this research, we present a case study on the toxicity hazards associated with alternative materials selection for CIGS manufacturing. We applied two numeric models, The Green Screen for Safer Chemicals and the Toxic Potential Indicator. To improve the sensitivity of the model outputs, we developed a novel, life cycle thinking based hazard assessment method that facilitates the projection of hazards throughout material life cycles. Our results show that the least hazardous CIGS solar cell device and manufacturing protocol consist of a titanium substrate, molybdenum metal back electrode, CuInS₂ p-type absorber deposited by spray pyrolysis, ZnS buffer deposited by spray ion layer gas reduction, ZnO:Ga transparent conducting oxide (TCO) deposited by sputtering, and the encapsulant polydimethylsiloxane. Copyright © 2013 Elsevier B.V. All rights reserved.

Selenization of CIS and CIGS layers deposited by chemical spray pyrolysis

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

Babu, B. J.; Egaas, B.; Velumani, S.

Cu(In1-xGax)Se2 (CIGS) thin films with x=0 (CIS) and x=0.3 (CIGS) were prepared on Mo-coated glass substrate by using chemical spray pyrolysis at a substrate temperature of 350 degrees C, followed by selenization treatment at 550 degrees C in selenium environment under N2 gas flow. X-ray diffraction patterns of as-deposited CIGS layers on Mo showed polycrystalline chalcopyrite phase with an intense (112) plane. Splitting of (204)/(220) and (116)/(312) planes for the film with x=0.3 reveals deviation of tetragonal nature. Field emission scanning electron microscopy cross-sectional images of selenized films showed clear re-crystallization of grains. During the selenization process of the CIGSmore » absorber, a thin interface layer of MoSe2 is formed. Line mapping of Mo/CIGS layer showed more gallium segregation at the interface of back contact resulting in band gap grading. Chemical composition and mapping of the as-deposited and selenized samples were determined by energy dispersive analysis of X-rays. This work leads to fabrication of low cost and large scale Mo/CIGS/CdS/ZnO/ZnO:Al device structure.« less

Chemical Bonding Technology: Direct Investigation of Interfacial Bonds

NASA Technical Reports Server (NTRS)

Koenig, J. L.; Boerio, F. J.; Plueddemann, E. P.; Miller, J.; Willis, P. B.; Cuddihy, E. F.

1986-01-01

This is the third Flat-Plate Solar Array (FSA) Project document reporting on chemical bonding technology for terrestrial photovoltaic (PV) modules. The impetus for this work originated in the late 1970s when PV modules employing silicone encapsulation materials were undergoing delamination during outdoor exposure. At that time, manufacturers were not employing adhesion promoters and, hence, module interfaces in common with the silicone materials were only in physical contact and therefore easily prone to separation if, for example, water were to penetrate to the interfaces. Delamination with silicone materials virtually vanished when adhesion promoters, recommended by silicone manufacturers, were used. The activities related to the direct investigation of chemically bonded interfaces are described.

Sustainability/Logistics-Basing Science and Technology Objective - Demonstration; Demonstration #2 - 300-Person Camp Demonstration

DTIC Science & Technology

2017-09-04

10 years @ 90% depth of discharge o Weight – 170 lb/374 kg  PV panels: 12 panels with a 3.36 kW solar array capacity  Generator: 10 kW TQG...lightweight thin-film PV panels ( solar modules or “ solar blankets”). These solar blankets were Door Sensor Figure 92: Temperature and Humidity Tripod...collected by various PV panels, and charging times for BB2590 batteries. 4.5.2 Operational Script The experimental nano-coated solar panel

Bifacial PV cell with reflector for stand-alone mast for sensor powering purposes

NASA Astrophysics Data System (ADS)

Jakobsen, Michael L.; Thorsteinsson, Sune; Poulsen, Peter B.; Riedel, N.; Rødder, Peter M.; Rødder, Kristin

2017-09-01

Reflectors to bifacial PV-cells are simulated and prototyped in this work. The aim is to optimize the reflector to specific latitudes, and particularly northern latitudes. Specifically, by using minimum semiconductor area the reflector must be able to deliver the electrical power required at the condition of minimum solar travel above the horizon, worst weather condition etc. We will test a bifacial PV-module with a retroreflector, and compare the output with simulations combined with local solar data.

Development of Manufacturing Technology to Accelerate Cost Reduction of Low Concentration and

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

Detrick, Adam

The purpose of this project was to accelerate deployment of cost-effective US-based manufacturing of Solaria’s unique c-Si module technology. This effort successfully resulted in the development of US-based manufacturing technology to support two highly-differentiated, market leading product platforms. The project was initially predicated on developing Solaria’s low-concentration PV (LCPV) module technology which at the time of the award was uniquely positioned to exceed the SunShot price goal of $0.50/Wp for standard c-Si modules. The Solaria LCPV module is a 2.5x concentrator that leverages proven, high-reliability PV module materials and low silicon cell usage into a technology package that already hadmore » the lowest direct material cost and leading Levelized Cost of Electricity (LCOE). With over 25 MW commercially deployed globally, the Solaria module was well positioned to continue to lead in PV module cost reduction. Throughout the term of the contract, market conditions changed dramatically and so to did Solaria’s product offerings to support this. However, the manufacturing technology developed for the LCPV module was successfully leveraged and optimized to support two new and different product platforms. BIPV “PowerVision” and High-efficiency “PowerXT” modules. The primary barrier to enabling high-volume PV module manufacturing in the US is the high manual labor component in certain unique aspects of our manufacturing process. The funding was used to develop unique manufacturing automation which makes the manual labor components of these key processes more efficient and increase throughput. At the core of Solaria’s product offerings are its unique and proprietary techniques for dicing and re-arranging solar cells into modules with highly-differentiated characteristics that address key gaps in the c-Si market. It is these techniques that were successfully evolved and deployed into US-based manufacturing site with SunShot funding. Today, Solaria is currently positioned to become the market leader with these two technologies over the coming 24 months largely due to the successful innovations of the underlying manufacturing technology. This success will leverage US-based manufacturing technology and the associated US-jobs to support. Solaria views the project as highly successful and a great example of SunShot funding enabling the creating of US jobs and the deployment of ubiquitous solar energy products.« less

Kent Terwilliger | NREL

Science.gov Websites

Science Kent.Terwilliger@nrel.gov | 303-384-6254 Research Interests Environmental Testing of PV Modules Maintenance and operation of environmental testing; tracking of module testing. Troubleshooting and repairing

Performance analysis of ‘Perturb and Observe’ and ‘Incremental Conductance’ MPPT algorithms for PV system

NASA Astrophysics Data System (ADS)

Lodhi, Ehtisham; Lodhi, Zeeshan; Noman Shafqat, Rana; Chen, Fieda

2017-07-01

Photovoltaic (PV) system usually employed The Maximum power point tracking (MPPT) techniques for increasing its efficiency. The performance of the PV system perhaps boosts by controlling at its apex point of power, in this way maximal power can be given to load. The proficiency of a PV system usually depends upon irradiance, temperature and array architecture. PV array shows a non-linear style for V-I curve and maximal power point on V-P curve also varies with changing environmental conditions. MPPT methods grantees that a PV module is regulated at reference voltage and to produce entire usage of the maximal output power. This paper gives analysis between two widely employed Perturb and Observe (P&O) and Incremental Conductance (INC) MPPT techniques. Their performance is evaluated and compared through theoretical analysis and digital simulation on the basis of response time and efficiency under varying irradiance and temperature condition using Matlab/Simulink.

Practical design considerations for photovoltaic power station

NASA Astrophysics Data System (ADS)

Swanson, T. D.

Aspects of photovoltaic (PV) technology are discussed along with generic PV design considerations, taking into account the resource sunlight, PV modules and their reliability, questions of PV system design, the support structure subsystem, and a power conditioning unit subsystem. A description is presented of two recent projects which demonstrate the translation of an idea into actual working PV systems. A privately financed project in Denton, Maryland, went on line in early December, 1982, and began providing power to the local utility grid. It represents the first intermediate size, grid-connected, privately financed power station in the U.S. Based on firm quotes, the actual cost of this system is about $13/W peak. The other project, called the PV Breeder, is an energy independent facility which utilizes solar power to make new solar cells. It is also the first large industrial structure completely powered by the sun.

Development of Cu(In,Ga)Se2 Test Coupons for Potential Induced Degradation Studies

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

Contreras, Miguel A.; Hacke, Peter; Repins, Ingrid

We report on the design, fabrication and accelerated testing of fully encapsulated small area coupons (approximately 7.5cm x 7.5 cm) for the purpose of researching potential induced degradation in Cu(In, Ga)Se2 based PV modules. The fabrication of these coupons enables the study of the solar cells and the materials used in PV module manufacturing such as top and bottom glass covers of different composition (soda-lime glass, high temperature glass, alkaline-free glass, etc), plastic-based top covers, ethylene vinyl acetate and edge seal encapsulation materials. The coupons can also be used to emulate framed and frameless modules that utilize either monolithically interconnectedmore » modules or singular cell type of modules. The design of the coupons, their fabrication, the materials used and their testing for 1000 hours under 85 degrees C and 85% RH conditions are presented.« less

Cu(In,Ga)S2, Thin-Film Solar Cells Prepared by H2S Sulfurization of CuGa-In Precursor

NASA Technical Reports Server (NTRS)

Dhere, Neelkanth G.; Kulkarni, Shashank R.; Chavan, Sanjay S.; Ghongadi, Shantinath R.

2005-01-01

Thin-film CuInS2 solar cell is the leading candidate for space power because of bandgap near the optimum value for AM0 solar radiation outside the earth's atmosphere, excellent radiation hardness, and freedom from intrinsic degradation mechanisms unlike a-Si:H cells. Ultra-lightweight thin-film solar cells deposited on flexible polyimide plastic substrates such as Kapton(trademark), Upilex(trademark), and Apical(trademark) have a potential for achieving specific power of 1000 W/kg, while the state-of-art specific power of the present day solar cells is 66 W/kg. This paper describes the preparation of Cu-rich CuIn(sub 1-x)Ga(sub x)S(sub 2) (CIGS2) thin films and solar cells by a process of sulfurization of CuGa-In precursor similar to that being used for preparation of large-compact-grain CuIn(sub 1-x)Ga(sub x)Se2 thin films and efficient solar cells at FSEC PV Materials Lab.

Influence of sputtering deposition parameters on electrical and optical properties of aluminium-doped zinc oxide thin films for photovoltaic applications

NASA Astrophysics Data System (ADS)

Krawczak, Ewelina; Agata, Zdyb; Gulkowski, Slawomir; Fave, Alain; Fourmond, Erwann

2017-11-01

Transparent Conductive Oxides (TCOs) characterized by high visible transmittance and low electrical resistivity play an important role in photovoltaic technology. Aluminum doped zinc oxide (AZO) is one of the TCOs that can find its application in thin film solar cells (CIGS or CdTe PV technology) as well as in other microelectronic applications. In this paper some optical and electrical properties of ZnO:Al thin films deposited by RF magnetron sputtering method have been investigated. AZO layers have been deposited on the soda lime glass substrates with use of variable technological parameters such as pressure in the deposition chamber, power applied and temperature during the process. The composition of AZO films has been investigated by EDS method. Thickness and refraction index of the deposited layers in dependence on certain technological parameters of sputtering process have been determined by spectroscopic ellipsometry. The measurements of transmittance and sheet resistance were also performed.

Overview of the Photovoltaic Manufacturing Technology (PVMaT) project

NASA Astrophysics Data System (ADS)

Witt, C. E.; Mitchell, R. L.; Mooney, G. D.

1993-08-01

The Photovoltaic Manufacturing Technology (PVMaT) project is a historic government/industry photovoltaic (PV) manufacturing R&D partnership composed of joint efforts between the federal government (through the US Department of Energy) and members of the US PV industry. The project's ultimate goal is to ensure that the US industry retains and extends its world leadership role in the manufacture and commercial development of PV components and systems. PVMaT is designed to do this by helping the US PV industry improve manufacturing processes, accelerate manufacturing cost reductions for PV modules, improve commercial product performance, and lay the groundwork for a substantial scale-up of US-based PV manufacturing capacities. Phase 1 of the project, the problem identification phase, was completed in early 1991. Phase 2, the problem solution phase, which addresses process-specific problems of specific manufacturers, is now underway with an expected duration of 5 years. Phase 3 addresses R&D problems that are relatively common to a number of PV companies or the PV industry as a whole. These 'generic' problem areas are being addressed through a teamed research approach.

The Class II Trehalose 6-phosphate Synthase Gene PvTPS9 Modulates Trehalose Metabolism in Phaseolus vulgaris Nodules

PubMed Central

Barraza, Aarón; Contreras-Cubas, Cecilia; Estrada-Navarrete, Georgina; Reyes, José L.; Juárez-Verdayes, Marco A.; Avonce, Nelson; Quinto, Carmen; Díaz-Camino, Claudia; Sanchez, Federico

2016-01-01

Legumes form symbioses with rhizobia, producing nitrogen-fixing nodules on the roots of the plant host. The network of plant signaling pathways affecting carbon metabolism may determine the final number of nodules. The trehalose biosynthetic pathway regulates carbon metabolism and plays a fundamental role in plant growth and development, as well as in plant-microbe interactions. The expression of genes for trehalose synthesis during nodule development suggests that this metabolite may play a role in legume-rhizobia symbiosis. In this work, PvTPS9, which encodes a Class II trehalose-6-phosphate synthase (TPS) of common bean (Phaseolus vulgaris), was silenced by RNA interference in transgenic nodules. The silencing of PvTPS9 in root nodules resulted in a reduction of 85% (± 1%) of its transcript, which correlated with a 30% decrease in trehalose contents of transgenic nodules and in untransformed leaves. Composite transgenic plants with PvTPS9 silenced in the roots showed no changes in nodule number and nitrogen fixation, but a severe reduction in plant biomass and altered transcript profiles of all Class II TPS genes. Our data suggest that PvTPS9 plays a key role in modulating trehalose metabolism in the symbiotic nodule and, therefore, in the whole plant. PMID:27847509

MPPT Algorithm Development for Laser Powered Surveillance Camera Power Supply Unit

NASA Astrophysics Data System (ADS)

Zhang, Yungui; Dushantha Chaminda, P. R.; Zhao, Kun; Cheng, Lin; Jiang, Yi; Peng, Kai

2018-03-01

Photovoltaics (PV) cells, modules which are semiconducting materials, convert light energy into electricity. Operation of a PV cell requires 3 basic features. When the light is absorbed it generate pairs of electron holes or excitons. An external circuit carrier opposite types of electrons irrespective of the source (sunlight or LASER light). The PV arrays have photovoltaic effect and the PV cells are defined as a device which has electrical characteristics: such as current, voltage and resistance. It varies when exposed to light, that the power output is depend on direct Laser-light. In this paper Laser-light to electricity by direct conversion with the use of PV cells and its concept of Band gap Energy, Series Resistance, Conversion Efficiency and Maximum Power Point Tracking (MPPT) methods [1].

Nanotechnologies for efficient solar and wind energy harvesting and storage

NASA Astrophysics Data System (ADS)

Eldada, Louay A.

2010-08-01

We describe nanotechnologies used to improve the efficient harvest of energy from the Sun and the wind, and the efficient storage of energy in secondary batteries and ultracapacitors, for use in a variety of applications including smart grids, electric vehicles, and portable electronics. We demonstrate high-quality nanostructured copper indium gallium selenide (CIGS) thin films for photovoltaic (PV) applications. The self-assembly of nanoscale p-n junction networks creates n-type networks that act as preferential electron pathways, and p-type networks that act as preferential hole pathways, allowing positive and negative charges to travel to the contacts in physically separated paths, reducing charge recombination. We also describe PV nanotechnologies used to enhance light trapping, photon absorption, charge generation, charge transport, and current collection. Furthermore, we describe nanotechnologies used to improve the efficiency of power-generating wind turbines. These technologies include nanoparticle-containing lubricants that reduce the friction generated from the rotation of the turbines, nanocoatings for de-icing and self-cleaning technologies, and advanced nanocomposites that provide lighter and stronger wind blades. Finally, we describe nanotechnologies used in advanced secondary batteries and ultracapacitors. Nanostructured powder-based and carbon-nanotube-based cathodes and anodes with ultra-high surface areas boost the energy and power densities in secondary batteries, including lithium-ion and sodium-sulfur batteries. Nanostructured carbon materials are also controlled on a molecular level to offer large surface areas for the electrodes of ultracapacitors, allowing to store and supply large bursts of energy needed in some applications.

The application of the Luus-Jaakola direct search method to the optimization of a hybrid renewable energy system

NASA Astrophysics Data System (ADS)

Jatzeck, Bernhard Michael

2000-10-01

The application of the Luus-Jaakola direct search method to the optimization of stand-alone hybrid energy systems consisting of wind turbine generators (WTG's), photovoltaic (PV) modules, batteries, and an auxiliary generator was examined. The loads for these systems were for agricultural applications, with the optimization conducted on the basis of minimum capital, operating, and maintenance costs. Five systems were considered: two near Edmonton, Alberta, and one each near Lethbridge, Alberta, Victoria, British Columbia, and Delta, British Columbia. The optimization algorithm used hourly data for the load demand, WTG output power/area, and PV module output power. These hourly data were in two sets: seasonal (summer and winter values separated) and total (summer and winter values combined). The costs for the WTG's, PV modules, batteries, and auxiliary generator fuel were full market values. To examine the effects of price discounts or tax incentives, these values were lowered to 25% of the full costs for the energy sources and two-thirds of the full cost for agricultural fuel. Annual costs for a renewable energy system depended upon the load, location, component costs, and which data set (seasonal or total) was used. For one Edmonton load, the cost for a renewable energy system consisting of 27.01 m2 of WTG area, 14 PV modules, and 18 batteries (full price, total data set) was 6873/year. For Lethbridge, a system with 22.85 m2 of WTG area, 47 PV modules, and 5 batteries (reduced prices, seasonal data set) cost 2913/year. The performance of renewable energy systems based on the obtained results was tested in a simulation using load and weather data for selected days. Test results for one Edmonton load showed that the simulations for most of the systems examined ran for at least 17 hours per day before failing due to either an excessive load on the auxiliary generator or a battery constraint being violated. Additional testing indicated that increasing the generator capacity and reducing the maximum allowed battery charge current during the time of the day at which these failures occurred allowed the simulation to successfully operate.

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

Photovoltaic Research | NREL

Science.gov Websites

the cost of solar cells, modules, and systems; and improving the reliability of PV components and Science-funded Center for Next Generation of Materials by Design. Reliability. Real-Time PV and Solar Research Solar panels line the rooftop of the parking garage at the south table mountain campus of

Photovoltaic Module Soiling Map | Photovoltaic Research | NREL

Science.gov Websites

proposed in: M. Deceglie, L. Micheli, and M. Muller, "Quantifying soiling loss directly from PV yield described in: L. Micheli and M. Muller, "An investigation of the key parameters for predicting PV : M. Muller, L. Micheli, and A.A. Martinez-Morales, "A Method to Extract Soiling Loss Data from

Degradation in PV Encapsulant Strength of Attachment: An Interlaboratory Study Towards a Climate-Specific Test: Preprint

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

Miller, David C.; Annigoni, Eleonora; Ballion, Amal

Reduced strength of attachment of the encapsulant resulting from outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PV installationsmore » was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, shear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces.« less

Recent Progress in CuInS2 Thin-Film Solar Cell Research at NASA Glenn

NASA Technical Reports Server (NTRS)

Jin, M. H.-C.; Banger, K. K.; Kelly, C. V.; Scofield, J. H.; McNatt, J. S.; Dickman, J. E.; Hepp, A. F.

2005-01-01

The National Aeronautics and Space Administration (NASA) is interested in developing low-cost highly efficient solar cells on light-weight flexible substrates, which will ultimately lower the mass-specific power (W/kg) of the cell allowing extra payload for missions in space as well as cost reduction. In addition, thin film cells are anticipated to have greater resistance to radiation damage in space, prolonging their lifetime. The flexibility of the substrate has the added benefit of enabling roll-to-roll processing. The first major thin film solar cell was the "CdS solar cell" - a heterojunction between p-type CuxS and n-type CdS. The research on CdS cells started in the late 1950s and the efficiency in the laboratory was up to about 10 % in the 1980s. Today, three different thin film materials are leading the field. They include amorphous Si, CdTe, and Cu(In,Ga)Se2 (CIGS). The best thin film solar cell efficiency of 19.2 % was recently set by CIGS on glass. Typical module efficiencies, however, remain below 15 %.

A Sensitivity Study of the Impact of Installation Parameters and System Configuration on the Performance of Bifacial PV Arrays

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

Marion, William F; Deline, Christopher A; Asgharzadeh, Amir

In this paper, we present the effect of installation parameters (tilt angle, height above ground, and albedo) on the bifacial gain and energy yield of three south-facing photovoltaic (PV) system configurations: a single module, a row of five modules, and five rows of five modules utilizing RADIANCE-based ray tracing model. We show that height and albedo have a direct impact on the performance of bifacial systems. However, the impact of the tilt angle is more complicated. Seasonal optimum tilt angles are dependent on parameters such as height, albedo, size of the system, weather conditions, and time of the year. Formore » a single bifacial module installed in Albuquerque, NM, USA (35 degrees N) with a reasonable clearance (~1 m) from the ground, the seasonal optimum tilt angle is lowest (~5 degrees) for the summer solstice and highest (~65 degrees) for the winter solstice. For larger systems, seasonal optimum tilt angles are usually higher and can be up to 20 degrees greater than that for a single module system. Annual simulations also indicate that for larger fixed-tilt systems installed on a highly reflective ground (such as snow or a white roofing material with an albedo of ~81%), the optimum tilt angle is higher than the optimum angle of the smaller size systems. We also show that modules in larger scale systems generate lower energy due to horizon blocking and large shadowing area cast by the modules on the ground. For albedo of 21%, the center module in a large array generates up to 7% less energy than a single bifacial module. To validate our model, we utilize measured data from Sandia National Laboratories' fixed-tilt bifacial PV testbed and compare it with our simulations.« less

26+ Year Old Photovoltaic Power Plant: Degradation and Reliability Evaluation of Crystalline Silicon Modules -- South Array

NASA Astrophysics Data System (ADS)

Olakonu, Kolapo

As the use of photovoltaic (PV) modules in large power plants continues to increase globally, more studies on degradation, reliability, failure modes, and mechanisms of field aged modules are needed to predict module life expectancy based on accelerated lifetime testing of PV modules. In this work, a 26+ year old PV power plant in Phoenix, Arizona has been evaluated for performance, reliability, and durability. The PV power plant, called Solar One, is owned and operated by John F. Long's homeowners association. It is a 200 kW dc, standard test conditions (STC) rated power plant comprised of 4000 PV modules or frameless laminates, in 100 panel groups (rated at 175 kW ac). The power plant is made of two center-tapped bipolar arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the south array and the other thesis presents the results obtained on the north array. Each of these two arrays is made of four sub arrays, the east sub arrays (positive and negative polarities) and the west sub arrays (positive and negative polarities), making up eight sub arrays. The evaluation and analyses of the power plant included in this thesis consists of: visual inspection, electrical performance measurements, and infrared thermography. A possible presence of potential induced degradation (PID) due to potential difference between ground and strings was also investigated. Some installation practices were also studied and found to contribute to the power loss observed in this investigation. The power output measured in 2011 for all eight sub arrays at STC is approximately 76 kWdc and represents a power loss of 62% (from 200 kW to 76 kW) over 26+ years. The 2011 measured power output for the four south sub arrays at STC is 39 kWdc and represents a power loss of 61% (from 100 kW to 39 kW) over 26+ years. Encapsulation browning and non-cell interconnect ribbon breakages were determined to be the primary causes for the power loss.

Long-term photothermal/humidity testing of photovoltaic module polymer insulations and cover films

NASA Technical Reports Server (NTRS)

Mon, G.; Gonzales, C.; Willis, P.; Jetter, E.; Sugimura, R.

1990-01-01

The life expectancies of Tedlar and other polymer films considered for use as cover materials in terrestrial photovoltaic (PV) modules were investigated by exposing them for more than 13,000 h on an outdoor test stand and for up to 10,000 h in several accelerated multistress environments. Visual observations and diagnostic analyses of weight and mechanical strength losses were periodically conducted to assess the nature and rate of degradation of mechanical properties and to assess the effects of film thickness and UV stabilizer content. Spectroscopic analyses of pristine and degraded materials linked weight and mechanical property losses to the underlying photothermal/photooxidation chemistry. It is shown that heavy doses of UV stabilizers prolong, while elevated temperatures shorten, the useful life of these materials; humidity plays only a minor role. The most heavily UV-stabilized films are expected to operate usefully in a PV module front-cover application for only five to ten years. The performance of none of the tested films appears consistent with the 20-30 year life goals of the PV industry.

Novel in situ resistance measurement for the investigation of CIGS growth in a selenization process

NASA Astrophysics Data System (ADS)

Liu, Wei; Tian, Jian-Guo; Li, Zu-Bin; He, Qing; Li, Feng-Yan; Li, Chang-Jian; Sun, Yun

2009-03-01

During the selenization process of CIGS thin films, the relation between the element loss rate and the precursor depositions are analyzed. The growth of the CIGS thin films during the selenization process is investigated by the novel in situ resistance measurement, by which the formation of compound semiconductors can be observed directly and simultaneously. Their structures, phase evolutions and element losses are analyzed by XRD and XRF. Based on the experimental results, it can be concluded that the phase transforms have nothing to do with the deposition sequences of precursors, while the element loss rates are related to the deposition sequences in this process. In addition, element loss mechanisms of CIGS thin films prepared by the selenization process are analyzed by the phase evolutions and chemical combined path in the In, Ga-Se reaction processes. Moreover it is verified that the element losses are depressed by increasing the ramping-up rate finally. The results provide effective methods to fabricate high-quality CIGS thin films with low element losses.

Mike Kempe | NREL

Science.gov Websites

cells and modules. His work concerns primarily modeling and measuring moisture ingress into PV modules and studying the effect of moisture on polymer adhesion, device performance, and component corrosion Photovoltaic Modules." Solar Energy Materials and Solar Cells, 90: 2720-2738. View all NREL publications

The reliability and stability of multijunction amorphous silicon PV modules

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

Carlson, D.E.

1995-11-01

Solarex is developing a manufacturing process for the commercial production of 8 ft{sup 2} multijunction amorphous silicon (a-Si) PV modules starting in 1996. The device structure used in these multijunction modules is: glass/textured tin oxide/p-i-n/p-i-n/ZnO/Al/EVA/Tedlar where the back junction of the tandem structure contains an amorphous silicon germanium alloy. As an interim step, 4 ft{sup 2} multijunction modules have been fabricated in a pilot production mode over the last several months. The distribution of initial conversion efficiencies for an engineering run of 67 modules (4 ft{sup 2}) is shown. Measurements recently performed at NREL indicate that the actual efficiencies aremore » about 5% higher than those shown, and thus exhibit an average initial conversion efficiency of about 9.5%. The data indicates that the process is relatively robust since there were no modules with initial efficiencies less than 7.5%.« less

Impact of heavy soiling on the power output of PV modules

NASA Astrophysics Data System (ADS)

Schill, Christian; Brachmann, Stefan; Heck, Markus; Weiss, Karl-Anders; Koehl, Michael

2011-09-01

Fraunhofer ISE is running a PV-module outdoor testing set-up on the Gran Canaria island, one of the Canary Island located west of Morroco in the Atlantic Ocean. The performance of the modules is assessed by IV-curve monitoring every 10 minutes. The electronic set-up of the monitoring system - consisting of individual electronic loads for each module which go into an MPP-tracking mode between the IV-measurements - will be described in detail. Soiling of the exposed modules happened because of building constructions nearby. We decided not to clean the modules, but the radiation sensors and recorded the decrease of the power output and the efficiency over time. The efficiency dropped to 20 % within 5 months before a heavy rain and subsequently the service personnel on site cleaned the modules. A smaller rain-fall in between washed the dust partly away and accumulated it at the lower part of the module, what could be concluded from the shape of the IV-curves, which were similar to partial shading by hot-spot-tests and by partial snow cover.

Methods of forming CIGS films

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

Mansfield, Lorelle; Ramanathan, Kannan

2017-09-19

Methods for forming CIGS films are provided. According to an aspect of the invention, a method of forming a CIGS film includes a precursor step, which includes simultaneously evaporating Cu, In, Ga, Se, and Sb onto a substrate. The Se is incident on the substrate at a rate of at least 20 .ANG./s. The method also includes a selenization step, which includes evaporating Se over the substrate after the precursor step.

Alternative buffer layer development in Cu(In,Ga)Se2 thin film solar cells

NASA Astrophysics Data System (ADS)

Xin, Peipei

Cu(In,Ga)Se2-based thin film solar cells are considered to be one of the most promising photovoltaic technologies. Cu(In,Ga)Se2 (CIGS) solar devices have the potential advantage of low-cost, fast fabrication by using semiconductor layers of only a few micrometers thick and high efficiency photovoltaics have been reported at both the cell and the module levels. CdS via chemical bath deposition (CBD) has been the most widely used buffer option to form the critical junction in CIGS-based thin film photovoltaic devices. However, the disadvantages of CdS can’t be ignored - regulations on cadmium usage are getting stricter primarily due to its toxicity and environmental impacts, and the proper handling of the large amount of toxic chemical bath waste is a massive and expensive task. This dissertation is devoted to the development of Cd-free alternative buffer layers in CIGS-based thin film solar cells. Based on the considerations of buffer layer selection criteria and extensive literature review, Zn-compound buffer materials are chosen as the primary investigation candidates. Radio frequency magnetron sputtering is the preferred buffer deposition approach since it’s a clean and more controllable technique compared to CBD, and is readily scaled to large area manufacturing. First, a comprehensive study of the ZnSe1-xOx compound prepared by reactive sputtering was completed. As the oxygen content in the reactive sputtering gas increased, ZnSe1-xOx crystallinity and bandgap decreased. It’s observed that oxygen miscibility in ZnSe was low and a secondary phase formed when the O2 / (O2 + Ar) ratio in the sputtering gas exceeded 2%. Two approaches were proposed to optimize the band alignment between the CIGS and buffer layer. One method focused on the bandgap engineering of the absorber, the other focused on the band structure modification of the buffer. As a result, improved current of the solar cell was achieved although a carrier transport barrier at the junction interface still limited the device performance. Second, an investigation of Zn(S,O) buffer layers was completed. Zn(S,O) films were sputtered in Ar using a ZnO0.7S0.3 compound target. Zn(S,O) films had the composition close to the target with S / (S+O) ratio around 0.3. Zn(S,O) films showed the wurtzite structure with the bandgap about 3.2eV. The champion Cu(In,Ga)Se2 / Zn(S,O) cell had 12.5% efficiency and an (Ag,Cu)(In,Ga)Se2 / Zn(S,O) cell achieved 13.2% efficiency. Detailed device analysis was used to study the Cu(In,Ga)Se2 and (Ag,Cu)(In,Ga)Se2 absorbers, the influence of absorber surface treatments, the effects of device treatments, the sputtering damage and the Na concentration in the absorber. Finally alternative buffer layer development was applied to an innovative superstrate CIGS configuration. The superstrate structure has potential benefits of improved window layer properties, cost reduction, and the possibility to implement back reflector engineering techniques. The application of three buffer layer options - CdS, ZnO and ZnSe was studied and limitations of each were characterized. The best device achieved 8.6% efficiency with a ZnO buffer. GaxOy formation at the junction interface was the main limiting factor of this device performance. For CdS / CIGS and ZnSe / CIGS superstrate devices extensive inter-diffusion between the absorber and buffer layer under CIGS growth conditions was the critical problem. Inter-diffusion severely deteriorated the junction quality and led to poorly behaved devices, despite different efforts to optimize the fabrication process.

CIG-P: Circular Interaction Graph for Proteomics.

PubMed

Hobbs, Christopher K; Leung, Michelle; Tsang, Herbert H; Ebhardt, H Alexander

2014-10-31

A typical affinity purification coupled to mass spectrometry (AP-MS) experiment includes the purification of a target protein (bait) using an antibody and subsequent mass spectrometry analysis of all proteins co-purifying with the bait (aka prey proteins). Like any other systems biology approach, AP-MS experiments generate a lot of data and visualization has been challenging, especially when integrating AP-MS experiments with orthogonal datasets. We present Circular Interaction Graph for Proteomics (CIG-P), which generates circular diagrams for visually appealing final representation of AP-MS data. Through a Java based GUI, the user inputs experimental and reference data as file in csv format. The resulting circular representation can be manipulated live within the GUI before exporting the diagram as vector graphic in pdf format. The strength of CIG-P is the ability to integrate orthogonal datasets with each other, e.g. affinity purification data of kinase PRPF4B in relation to the functional components of the spliceosome. Further, various AP-MS experiments can be compared to each other. CIG-P aids to present AP-MS data to a wider audience and we envision that the tool finds other applications too, e.g. kinase - substrate relationships as a function of perturbation. CIG-P is available under: http://sourceforge.net/projects/cig-p/

Comparative effects between electronic and cigarette smoke in human keratinocytes and epithelial lung cells.

PubMed

Cervellati, F; Muresan, X M; Sticozzi, C; Gambari, R; Montagner, G; Forman, H J; Torricelli, C; Maioli, E; Valacchi, G

2014-08-01

Information about the harmful effects of vaping is sparse and inconsistent, therefore, since the use of electronic cigarettes (e-CIGs) has become increasingly popular as a tool to limit tobacco smoking, it is urgent to establish the toxicity of the commercial e-CIGs. Skin (HaCaT) and lung (A549) cells, the main targets of cigarette smoke (CS), were exposed to e-CIG vapor and CS using an in vitro system. The cytotoxic effect of the exposure was analyzed in both cell types by ultrastructural morphology, Trypan Blue exclusion test and LDH assay. In addition, pro-inflammatory cytokines were measured by the Bio-Plex assay. The cytotoxic components of e-CIG were restrained to the flavoring compound and, to a lesser extent, to nicotine although their effects were less harmful to that of CS. Humectants alone exhibited no cytotoxicity but induced the release of cytokines and pro-inflammatory mediators. Based on our results, we can state that exposure to e-CIG vapors results in far less toxic than exposure to CS. In fact, besides the deleterious effect of flavor and nicotine, even the humectants alone are able to evocate cytokines release. This study will hopefully promote the development of safer e-CIGs to help people quit smoking. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Cho, Youngho; Hur, Kyeon; Kang, Yong

This study investigates the emerging harmonic stability concerns to be addressed by grid planners in generation interconnection studies, owing to the increased adoption of renewable energy resources connected to the grid via power electronic converters. The wideband and high-frequency electromagnetic transient (EMT) characteristics of these converter-interfaced generators (CIGs) and their interaction with the grid impedance are not accurately captured in the typical dynamic studies conducted by grid planners. This paper thus identifies the desired components to be studied and subsequently develops a practical process for integrating a new CIG into a grid with the existing CIGs. The steps of thismore » process are as follows: the impedance equation of a CIG using its control dynamics and an interface filter to the grid, for example, an LCL filter (inductor-capacitor-inductor type), is developed; an equivalent impedance model including the existing CIGs nearby and the grid observed from the point of common coupling are derived; the system stability for credible operating scenarios is assessed. Detailed EMT simulations validate the accuracy of the impedance models and stability assessment for various connection scenarios. Here, by complementing the conventional EMT simulation studies, the proposed analytical approach enables grid planners to identify critical design parameters for seamlessly integrating a new CIG and ensuring the reliability of the grid.« less

Thin-film copper indium gallium selenide solar cell based on low-temperature all-printing process.

PubMed

Singh, Manjeet; Jiu, Jinting; Sugahara, Tohru; Suganuma, Katsuaki

2014-09-24

In the solar cell field, development of simple, low-cost, and low-temperature fabrication processes has become an important trend for energy-saving and environmental issues. Copper indium gallium selenide (CIGS) solar cells have attracted much attention due to the high absorption coefficient, tunable band gap energy, and high efficiency. However, vacuum and high-temperature processing in fabrication of solar cells have limited the applications. There is a strong need to develop simple and scalable methods. In this work, a CIGS solar cell based on all printing steps and low-temperature annealing is developed. CIGS absorber thin film is deposited by using dodecylamine-stabilized CIGS nanoparticle ink followed by printing buffer layer. Silver nanowire (AgNW) ink and sol-gel-derived ZnO precursor solution are used to prepare a highly conductive window layer ZnO/[AgNW/ZnO] electrode with a printing method that achieves 16 Ω/sq sheet resistance and 94% transparency. A CIGS solar cell based on all printing processes exhibits efficiency of 1.6% with open circuit voltage of 0.48 V, short circuit current density of 9.7 mA/cm(2), and fill factor of 0.34 for 200 nm thick CIGS film, fabricated under ambient conditions and annealed at 250 °C.

High-Resolution AES Mapping and TEM Study of Cu(In,Ga)Se2 Thin Film Growth: Preprint

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

Perkins, C. L.; Yan, Y.; Jones, K.

2001-10-01

Presented at 2001 NCPV Program Review Meeting: TEM and high-resolution AES mapping data on CIGS samples. The chalcopyrite Cu(In,Ga)Se{sub 2} (CIGS) shows promise as an absorber layer in thin polycrystalline solar cells, however, details of the PVD growth of this complicated material remain in a developing stage. Previous workers have postulated the existence of a thin film of liquid Cu{sub x}Se on the growing CIGS film, and that this layer acts as a reservoir of copper as well as a layer in which rapid mass transport is possible. In this paper we present transmission electron microscopy (TEM) and high resolutionmore » Auger electron spectroscopy (AES) mapping data taken on samples that had their growth interrupted at a stage when Cu{sub x}Se was expected to be present. The AES maps show CIGS grains which are highly enriched in copper relative to the rest of the CIGS film, and that these same areas contain almost no indium, results consistent with the presence of CuxSe. Small-area diffraction analysis and energy dispersive spectroscopy (EDS) performed on these same samples independently confirm the presence of Cu{sub x}Se at the surface of growing CIGS films.« less

Employing Si solar cell technology to increase efficiency of ultra-thin Cu(In,Ga)Se2 solar cells.

PubMed

Vermang, Bart; Wätjen, Jörn Timo; Fjällström, Viktor; Rostvall, Fredrik; Edoff, Marika; Kotipalli, Ratan; Henry, Frederic; Flandre, Denis

2014-10-01

Reducing absorber layer thickness below 500 nm in regular Cu(In,Ga)Se 2 (CIGS) solar cells decreases cell efficiency considerably, as both short-circuit current and open-circuit voltage are reduced because of incomplete absorption and high Mo/CIGS rear interface recombination. In this work, an innovative rear cell design is developed to avoid both effects: a highly reflective rear surface passivation layer with nano-sized local point contact openings is employed to enhance rear internal reflection and decrease the rear surface recombination velocity significantly, as compared with a standard Mo/CIGS rear interface. The formation of nano-sphere shaped precipitates in chemical bath deposition of CdS is used to generate nano-sized point contact openings. Evaporation of MgF 2 coated with a thin atomic layer deposited Al 2 O 3 layer, or direct current magnetron sputtering of Al 2 O 3 are used as rear surface passivation layers. Rear internal reflection is enhanced substantially by the increased thickness of the passivation layer, and also the rear surface recombination velocity is reduced at the Al 2 O 3 /CIGS rear interface. (MgF 2 /)Al 2 O 3 rear surface passivated ultra-thin CIGS solar cells are fabricated, showing an increase in short circuit current and open circuit voltage compared to unpassivated reference cells with equivalent CIGS thickness. Accordingly, average solar cell efficiencies of 13.5% are realized for 385 nm thick CIGS absorber layers, compared with 9.1% efficiency for the corresponding unpassivated reference cells.

Employing Si solar cell technology to increase efficiency of ultra-thin Cu(In,Ga)Se2 solar cells

PubMed Central

Vermang, Bart; Wätjen, Jörn Timo; Fjällström, Viktor; Rostvall, Fredrik; Edoff, Marika; Kotipalli, Ratan; Henry, Frederic; Flandre, Denis

2014-01-01

Reducing absorber layer thickness below 500 nm in regular Cu(In,Ga)Se2 (CIGS) solar cells decreases cell efficiency considerably, as both short-circuit current and open-circuit voltage are reduced because of incomplete absorption and high Mo/CIGS rear interface recombination. In this work, an innovative rear cell design is developed to avoid both effects: a highly reflective rear surface passivation layer with nano-sized local point contact openings is employed to enhance rear internal reflection and decrease the rear surface recombination velocity significantly, as compared with a standard Mo/CIGS rear interface. The formation of nano-sphere shaped precipitates in chemical bath deposition of CdS is used to generate nano-sized point contact openings. Evaporation of MgF2 coated with a thin atomic layer deposited Al2O3 layer, or direct current magnetron sputtering of Al2O3 are used as rear surface passivation layers. Rear internal reflection is enhanced substantially by the increased thickness of the passivation layer, and also the rear surface recombination velocity is reduced at the Al2O3/CIGS rear interface. (MgF2/)Al2O3 rear surface passivated ultra-thin CIGS solar cells are fabricated, showing an increase in short circuit current and open circuit voltage compared to unpassivated reference cells with equivalent CIGS thickness. Accordingly, average solar cell efficiencies of 13.5% are realized for 385 nm thick CIGS absorber layers, compared with 9.1% efficiency for the corresponding unpassivated reference cells. PMID:26300619

Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation

DOE PAGES

Lee, Kyu-Tae; Yao, Yuan; He, Junwen; ...

2016-12-05

Emerging classes ofconcentrator photovoltaic (CPV) modules reach efficiencies that are far greater than those of even the highest performance flat-plate PV technologies, with architectures that have the potential to provide the lowest cost of energy in locations with high direct normal irradiance (DNI). A disadvantage is their inability to effectively use diffuse sunlight, thereby constraining widespread geographic deployment and limiting performance even under the most favorable DNI conditions. This study introduces a module design that integrates capabilities in flat-plate PV directly with the most sophisticated CPV technologies, for capture of both direct and diffuse sunlight, thereby achieving efficiency in PVmore » conversion of the global solar radiation. Specific examples of this scheme exploit commodity silicon (Si) cells integrated with two different CPV module designs, where they capture light that is not efficiently directed by the concentrator optics onto large-scale arrays of miniature multijunction (MJ) solar cells that use advanced III-V semiconductor technologies. In this CPV + scheme ("+" denotes the addition of diffuse collector), the Si and MJ cells operate independently on indirect and direct solar radiation, respectively. On-sun experimental studies of CPV + modules at latitudes of 35.9886° N (Durham, NC), 40.1125° N (Bondville, IL), and 38.9072° N (Washington, DC) show improvements in absolute module efficiencies of between 1.02% and 8.45% over values obtained using otherwise similar CPV modules, depending on weather conditions. These concepts have the potential to expand the geographic reach and improve the cost-effectiveness of the highest efficiency forms of PV power generation.« less

Effect of e-Cigarette Use on Cough Reflex Sensitivity.

PubMed

Dicpinigaitis, Peter V; Lee Chang, Alfredo; Dicpinigaitis, Alis J; Negassa, Abdissa

2016-01-01

E-cigarettes (e-cigs) have attained widespread popularity, yet knowledge of their physiologic effects remains minimal. The aim of this study was to evaluate the effect of a single exposure to e-cig vapor on cough reflex sensitivity. Thirty healthy nonsmokers underwent cough reflex sensitivity measurement using capsaicin cough challenge at baseline, 15 min, and 24 h after e-cig exposure (30 puffs 30 s apart). The end point of cough challenge is the concentration of capsaicin inducing five or more coughs (C5). The number of coughs induced by each e-cig inhalation was counted. A subgroup of subjects (n = 8) subsequently underwent an identical protocol with a non-nicotine-containing e-cig. Cough reflex sensitivity was significantly inhibited (C5 increased) 15 min after e-cig use (?0.29; 95% CI, ?0.43 to ?0.15; P < .0001); 24 h later, C5 returned to baseline (0.24; 95% CI, 0.10-0.38; P = .0002 vs post-15-min value). A subgroup of eight subjects demonstrating the largest degree of cough reflex inhibition had no suppression after exposure to a non-nicotine-containing e-cig (P = .0078 for comparison of ?C5 after nicotine vs non-nicotine device). Furthermore, more coughing was induced by the nicotine-containing vs non-nicotine-containing device (P = .0156). A single session of e-cig use, approximating nicotine exposure of one tobacco cigarette, induces significant inhibition of cough reflex sensitivity. Exploratory analysis of a subgroup of subjects suggests that nicotine is responsible for this observation. Our data, consistent with previous studies of nicotine effect, suggest a dual action of nicotine: an immediate, peripheral protussive effect and a delayed central antitussive effect. ClinicalTrials.gov; No.: NCT02203162; URL: www.clinicaltrials.gov. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Expression of m1-type muscarinic acetylcholine receptors by parvalbumin-immunoreactive neurons in the primary visual cortex: a comparative study of rat, guinea pig, ferret, macaque, and human.

PubMed

Disney, Anita A; Reynolds, John H

2014-04-01

Cholinergic neuromodulation is a candidate mechanism for aspects of arousal and attention in mammals. We have reported previously that cholinergic modulation in the primary visual cortex (V1) of the macaque monkey is strongly targeted toward GABAergic interneurons, and in particular that the vast majority of parvalbumin-immunoreactive (PV) neurons in macaque V1 express the m1-type (pirenzepine-sensitive, Gq-coupled) muscarinic ACh receptor (m1AChR). In contrast, previous physiological data indicates that PV neurons in rats rarely express pirenzepine-sensitive muscarinic AChRs. To examine further this apparent species difference in the cholinergic effectors for the primary visual cortex, we have conducted a comparative study of the expression of m1AChRs by PV neurons in V1 of rats, guinea pigs, ferrets, macaques, and humans. We visualize PV- and mAChR-immunoreactive somata by dual-immunofluorescence confocal microscopy and find that the species differences are profound; the vast majority (>75%) of PV-ir neurons in macaques, humans, and guinea pigs express m1AChRs. In contrast, in rats only ∼25% of the PV population is immunoreactive for m1AChRs. Our data reveal that while they do so much less frequently than in primates, PV neurons in rats do express Gq-coupled muscarinic AChRs, which appear to have gone undetected in the previous in vitro studies. Data such as these are critical in determining the species that represent adequate models for the capacity of the cholinergic system to modulate inhibition in the primate cortex. Copyright © 2013 Wiley Periodicals, Inc.

Neuropeptide Y as a possible homeostatic element for changes in cortical excitability induced by repetitive transcranial magnetic stimulation.

PubMed

Jazmati, Danny; Neubacher, Ute; Funke, Klaus

2018-02-24

Repetitive transcranial magnetic stimulation (rTMS) is able to modify cortical excitability. Rat rTMS studies revealed a modulation of inhibitory systems, in particular that of the parvalbumin-expressing (PV+) interneurons, when using intermittent theta-burst stimulation (iTBS). The potential disinhibitory action of iTBS raises the questions of how neocortical circuits stabilize excitatory-inhibitory balance within a physiological range. Neuropeptide Y (NPY) appears to be one candidate. Analysis of cortical expression of PV, NPY and vesicular glutamate transporter type 1 (vGluT1) by immunohistochemical means at the level of cell counts, mean neuropil expression and single cell pre-/postsynaptic expression, with and without intraventricular NPY-injection. Our results show that iTBS not only reduced the number of neurons with high-PV expression in a dose-dependent fashion, but also increased the cortical expression of NPY, discussed to reduce glutamatergic transmission, and this was further associated with a reduced vGluT1 expression, an indicator of glutamateric presynaptic activity. Interneurons showing a low-PV expression exhibit less presynaptic vGluT1 expression compared to those with a high-PV expression. Intraventricular application of NPY prior to iTBS prevented the iTBS-induced reduction in the number of high-PV neurons, the reduction in tissue vGluT1 level and that presynaptic to high-PV cells. We conclude that NPY, possibly via a global but also slow homeostatic control of glutamatergic transmission, modulates the strength and direction of the iTBS effects, likely preventing pathological imbalance of excitatory and inhibitory cortical activity but still allowing enough disinhibition beneficial for plastic changes as during learning. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

First principles calculations of point defect diffusion in CdS buffer layers: Implications for Cu(In,Ga)(Se,S){sub 2} and Cu{sub 2}ZnSn(Se,S){sub 4}-based thin-film photovoltaics

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

Varley, J. B.; Lordi, V.; He, X.

2016-01-14

We investigate point defects in CdS buffer layers that may arise from intermixing with Cu(In,Ga)Se{sub 2} (CIGSe) or Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) absorber layers in thin-film photovoltaics (PV). Using hybrid functional calculations, we characterize the migration barriers of Cu, In, Ga, Se, Sn, Zn, Na, and K impurities and assess the activation energies necessary for their diffusion into the bulk of the buffer. We find that Cu, In, and Ga are the most mobile defects in CIGS-derived impurities, with diffusion expected to proceed into the buffer via interstitial-hopping and cadmium vacancy-assisted mechanisms at temperatures ∼400 °C. Cu is predicted to stronglymore » favor migration paths within the basal plane of the wurtzite CdS lattice, which may facilitate defect clustering and ultimately the formation of Cu-rich interfacial phases as observed by energy dispersive x-ray spectroscopic elemental maps in real PV devices. Se, Zn, and Sn defects are found to exhibit much larger activation energies and are not expected to diffuse within the CdS bulk at temperatures compatible with typical PV processing temperatures. Lastly, we find that Na interstitials are expected to exhibit slightly lower activation energies than K interstitials despite having a larger migration barrier. Still, we find both alkali species are expected to diffuse via an interstitially mediated mechanism at slightly higher temperatures than enable In, Ga, and Cu diffusion in the bulk. Our results indicate that processing temperatures in excess of ∼400 °C will lead to more interfacial intermixing with CdS buffer layers in CIGSe devices, and less so for CZTSSe absorbers where only Cu is expected to significantly diffuse into the buffer.« less

On-line monitoring system of PV array based on internet of things technology

NASA Astrophysics Data System (ADS)

Li, Y. F.; Lin, P. J.; Zhou, H. F.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.; Su, F. P.

2017-11-01

The Internet of Things (IoT) Technology is used to inspect photovoltaic (PV) array which can greatly improve the monitoring, performance and maintenance of the PV array. In order to efficiently realize the remote monitoring of PV operating environment, an on-line monitoring system of PV array based on IoT is designed in this paper. The system includes data acquisition, data gateway and PV monitoring centre (PVMC) website. Firstly, the DSP-TMS320F28335 is applied to collect indicators of PV array using sensors, then the data are transmitted to data gateway through ZigBee network. Secondly, the data gateway receives the data from data acquisition part, obtains geographic information via GPS module, and captures the scenes around PV array via USB camera, then uploads them to PVMC website. Finally, the PVMC website based on Laravel framework receives all data from data gateway and displays them with abundant charts. Moreover, a fault diagnosis approach for PV array based on Extreme Learning Machine (ELM) is applied in PVMC. Once fault occurs, a user alert can be sent via E-mail. The designed system enables users to browse the operating conditions of PV array on PVMC website, including electrical, environmental parameters and video. Experimental results show that the presented monitoring system can efficiently real-time monitor the PV array, and the fault diagnosis approach reaches a high accuracy of 97.5%.

Thin-film filament-based solar cells and modules

NASA Astrophysics Data System (ADS)

Tuttle, J. R.; Cole, E. D.; Berens, T. A.; Alleman, J.; Keane, J.

1997-04-01

This concept paper describes a patented, novel photovoltaic (PV) technology that is capable of achieving near-term commercialization and profitability based upon design features that maximize product performance while minimizing initial and future manufacturing costs. DayStar Technologies plans to exploit these features and introduce a product to the market based upon these differential positions. The technology combines the demonstrated performance and reliability of existing thin-film PV product with a cell and module geometry that cuts material usage by a factor of 5, and enhances performance and manufacturability relative to standard flat-plate designs. The target product introduction price is 1.50/Watt-peak (Wp). This is approximately one-half the cost of the presently available PV product. Additional features include: increased efficiency through low-level concentration, no scribe or grid loss, simple series interconnect, high voltage, light weight, high-throughput manufacturing, large area immediate demonstration, flexibility, modularity.

Military Energy Alternatives Conference

DTIC Science & Technology

2012-03-08

Power Generation and Alternative Energy Branch US Army RDECOM CERDEC CP&ID Power Division Aberdeen Proving Ground, MD...Co-generation Applications •Tactical Mobile Power •Vehicle-mounted Auxiliary Power and Environmental Control •Energy Security for Base...Mobile Power (PM MEP / PM CP) Vehicle Power (PM Tactical Vehicle / PM HTV) Portable Solar Photovoltaic (PV) Modules and Mobile Hybrid PV Power Sources

Hybrid Tandem Solar Cells | Photovoltaic Research | NREL

Science.gov Websites

Hybrid Tandem Solar Cells Hybrid Tandem Solar Cells To achieve aggressive cost reductions in photovoltaics (PV) beyond the 6¢/kWh SunShot Initiative 2020 goal, module efficiency must be increased beyond on a silicon platform and that aim to provide viable prototypes for commercialization. PV Research

Performance losses in rooftop-mounted PV modules from long-term environmental exposure at Las Cruces, New Mexico

NASA Astrophysics Data System (ADS)

Rosenthal, Andrew L.; Czanderna, A. W.; Pern, F. J.

1999-03-01

Forty-eight PV modules of four different types were instrumented and tested monthly for 3 years to measure and record the performance effects of environmental exposure. Two modules were removed from each set of 12 as a control and for "initial" characterization. As a secondary goal, the effects of mounting topology (open rack, integrated roof, conventional standoff mount) were also closely monitored. Current-voltage (I-V) curve data were archived and normalized according to accepted methods. The EVA pottant in all modules monitored was discolored to a deep yellow-to-brown color from prior exposures before the monitoring was begun. Modules showing observable performance degradation were removed from their mounts and prepared for in-depth analysis. During the 3-year monitoring period, 4 of the 10 Solarex a-Si modules stopped producing, 3 of the 10 Solarex MIT pc-Si modules lost from 5% to 10% efficiency, and 1 Mobil Ra-180 pc-Si module lost about 10% efficiency. For all of the other modules, a loss of less than 1% per year was recorded, which included all 10 of the Sovonics P-101 a-Si modules.

Robust PV Degradation Methodology and Application

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

Jordan, Dirk; Deline, Christopher A; Kurtz, Sarah

The degradation rate plays an important role in predicting and assessing the long-term energy generation of PV systems. Many methods have been proposed for extracting the degradation rate from operational data of PV systems, but most of the published approaches are susceptible to bias due to inverter clipping, module soiling, temporary outages, seasonality, and sensor degradation. In this manuscript, we propose a methodology for determining PV degradation leveraging available modeled clear-sky irradiance data rather than site sensor data, and a robust year-over-year (YOY) rate calculation. We show the method to provide reliable degradation rate estimates even in the case ofmore » sensor drift, data shifts, and soiling. Compared with alternate methods, we demonstrate that the proposed method delivers the lowest uncertainty in degradation rate estimates for a fleet of 486 PV systems.« less

Robust PV Degradation Methodology and Application

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

Jordan, Dirk C.; Deline, Chris; Kurtz, Sarah R.

The degradation rate plays an important role in predicting and assessing the long-term energy generation of photovoltaics (PV) systems. Many methods have been proposed for extracting the degradation rate from operational data of PV systems, but most of the published approaches are susceptible to bias due to inverter clipping, module soiling, temporary outages, seasonality, and sensor degradation. In this paper, we propose a methodology for determining PV degradation leveraging available modeled clear-sky irradiance data rather than site sensor data, and a robust year-over-year rate calculation. We show the method to provide reliable degradation rate estimates even in the case ofmore » sensor drift, data shifts, and soiling. Compared with alternate methods, we demonstrate that the proposed method delivers the lowest uncertainty in degradation rate estimates for a fleet of 486 PV systems.« less

Robust PV Degradation Methodology and Application

DOE PAGES

Jordan, Dirk C.; Deline, Chris; Kurtz, Sarah R.; ...

2017-12-21

The degradation rate plays an important role in predicting and assessing the long-term energy generation of photovoltaics (PV) systems. Many methods have been proposed for extracting the degradation rate from operational data of PV systems, but most of the published approaches are susceptible to bias due to inverter clipping, module soiling, temporary outages, seasonality, and sensor degradation. In this paper, we propose a methodology for determining PV degradation leveraging available modeled clear-sky irradiance data rather than site sensor data, and a robust year-over-year rate calculation. We show the method to provide reliable degradation rate estimates even in the case ofmore » sensor drift, data shifts, and soiling. Compared with alternate methods, we demonstrate that the proposed method delivers the lowest uncertainty in degradation rate estimates for a fleet of 486 PV systems.« less

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

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-fluoropolymer-based backsheets are discussed.« less

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 discussed.

Evaluation of moisture ingress from the perimeter of photovoltaic modules: Evaluation of moisture ingress

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

Kempe, Michael D.; Dameron, Arrelaine A.; Reese, Matthew O.

2013-05-14

Many thin film photovoltaic (PV) technologies can be sensitive to corrosion induced by the presence of water vapor in the packaging materials. Typically impermeable front and backsheets are used in conjunction with an edge-seal around the perimeter to prevent water vapor ingress. These edge-seal materials are often made of a polyisobutylene resin filled with desiccant, which dramatically increases the time for moisture to reach sensitive module components. While edge-seals can prevent moisture ingress, even the lowest diffusivity transparent encapsulant materials are insufficient for the lifetime of a module. To evaluate the performance of edge-seal and encapsulant materials in a mannermore » that simulates their function in a PV module, an optical method was devised where ingress is detected by reaction of a Ca film with water. Using this method, we have exposed test samples to heat and humidity allowing quantitative comparison of different edge-seal and encapsulant materials. Next, we use measurements of polymer diffusivity and solubility to evaluate the ability to model this moisture ingress. Here, we find good agreement between these two methods highlighting the much greater ability of polyisobutylene materials to keep moisture out as compared with typical encapsulant materials used in the PV industry.« less

SERVER DEVELOPMENT FOR NSLS-II PHYSICS APPLICATIONS AND PERFORMANCE ANALYSIS

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

Shen, G.; Kraimer, M.

2011-03-28

The beam commissioning software framework of NSLS-II project adopts a client/server based architecture to replace the more traditional monolithic high level application approach. The server software under development is available via an open source sourceforge project named epics-pvdata, which consists of modules pvData, pvAccess, pvIOC, and pvService. Examples of two services that already exist in the pvService module are itemFinder, and gather. Each service uses pvData to store in-memory transient data, pvService to transfer data over the network, and pvIOC as the service engine. The performance benchmarking for pvAccess and both gather service and item finder service are presented inmore » this paper. The performance comparison between pvAccess and Channel Access are presented also. For an ultra low emittance synchrotron radiation light source like NSLS II, the control system requirements, especially for beam control are tight. To control and manipulate the beam effectively, a use case study has been performed to satisfy the requirement and theoretical evaluation has been performed. The analysis shows that model based control is indispensable for beam commissioning and routine operation. However, there are many challenges such as how to re-use a design model for on-line model based control, and how to combine the numerical methods for modeling of a realistic lattice with the analytical techniques for analysis of its properties. To satisfy the requirements and challenges, adequate system architecture for the software framework for beam commissioning and operation is critical. The existing traditional approaches are self-consistent, and monolithic. Some of them have adopted a concept of middle layer to separate low level hardware processing from numerical algorithm computing, physics modelling, data manipulating and plotting, and error handling. However, none of the existing approaches can satisfy the requirement. A new design has been proposed by introducing service oriented architecture technology, and client interface is undergoing. The design and implementation adopted a new EPICS implementation, namely epics-pvdata [9], which is under active development. The implementation of this project under Java is close to stable, and binding to other language such as C++ and/or Python is undergoing. In this paper, we focus on the performance benchmarking and comparison for pvAccess and Channel Access, the performance evaluation for 2 services, gather and item finder respectively.« less

N-linked glycosylation of recombinant cellobiohydrolase I (Cel7A) from Penicillium verruculosum and its effect on the enzyme activity.

PubMed

Dotsenko, Anna S; Gusakov, Alexander V; Volkov, Pavel V; Rozhkova, Aleksandra M; Sinitsyn, Arkady P

2016-02-01

Cellobiohydrolase I from Penicillium verruculosum (PvCel7A) has four potential N-glycosylation sites at its catalytic module: Asn45, Asn194, Asn388, and Asn430. In order to investigate how the N-glycosylation influences the activity and other properties of the enzyme, the wild type (wt) PvCel7A and its mutant forms, carrying Asn to Ala substitutions, were cloned into Penicillium canescens PCA10 (niaD-) strain, a fungal host for production of heterologous proteins. The rPvCel7A-wt and N45A, N194A, N388A mutants were successfully expressed and purified for characterization, whereas the expression of N430A mutant was not achieved. The MALDI-TOF mass spectrometry fingerprinting of peptides, obtained as a result of digestion of rPvCel7A forms with specific proteases, showed that the N-linked glycans represent variable high-mannose oligosaccharides and the products of their sequential enzymatic trimming, according to the formula (Man)0-13 (GlcNAc)2 , or a single GlcNAc residue. Mutations had no notable effect on pH-optimum of PvCel7A activity and enzyme thermostability. However, the mutations influenced both the enzyme adsorption ability on Avicel and its activity against natural and synthetic substrates. In particular, the N45A mutation led to a significant increase in the rate of Avicel and milled aspen wood hydrolysis, while the substrate digestion rates in the case of N194A and N388A mutants were notably lower relative to rPvCel7A-wt. These data, together with data of 3D structural modeling of the PvCel7A catalytic module, indicate that the N-linked glycans are an important part of the processive catalytic machinery of PvCel7A. © 2015 Wiley Periodicals, Inc.

The AMIGA sample of isolated galaxies. XII. Revision of the isolation degree for AMIGA galaxies using the SDSS

NASA Astrophysics Data System (ADS)

Argudo-Fernández, M.; Verley, S.; Bergond, G.; Sulentic, J.; Sabater, J.; Fernández Lorenzo, M.; Leon, S.; Espada, D.; Verdes-Montenegro, L.; Santander-Vela, J. D.; Ruiz, J. E.; Sánchez-Expósito, S.

2013-12-01

Context. To understand the evolution of galaxies, it is necessary to have a reference sample where the effect of the environment is minimized and quantified. In the framework of the AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies), we present a revision of the environment for galaxies in the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973, Astrof. Issledovaniia Byu. Spec. Ast. Obs., 8, 3) using the ninth data release of the Sloan Digital Sky Survey (SDSS-DR9). Aims: The aims of this study are to refine the photometric-based AMIGA sample of isolated galaxies and to provide an improvement of the quantification of the isolation degree with respect to previous works, using both photometry and spectroscopy. Methods: We developed an automatic method to search for neighbours within a projected area of 1 Mpc radius centred on each primary galaxy to revise the CIG isolation criteria introduced by Karachentseva (1973). The local number density at the fifth nearest neighbour and the tidal strength affecting the CIG galaxy were estimated to quantify the isolation degree. Results: Of the 636 CIG galaxies considered in the photometric study, 426 galaxies fulfil the CIG isolation criteria within 1 Mpc, taking into account projected neighbours. Of the 411 CIG galaxies considered in the spectroscopic study, 347 galaxies fulfil the CIG isolation criteria when a criterion about redshift difference is added. The available redshifts allow us to reject background neighbours and thus improve the photometric assessment. On average, galaxies in the AMIGA sample show lower values in the local number density and the tidal strength parameters than galaxies in denser environments such as pairs, triplets, compact groups, and clusters. Conclusions: For the first time, the environment and the isolation degree of AMIGA galaxies are quantified using digital data. The use of the SDSS database permits one to identify fainter and smaller-size satellites than in previous AMIGA works. The AMIGA sample is improved by this study, because we reduced the sample of isolated galaxies used in previous AMIGA works by about 20%. The availability of the spectroscopic data allows us to check the validity of the CIG isolation criteria, which is not fully efficient. About 50% of the neighbours considered as potential companions in the photometric study are in fact background objects. We also find that about 92% of the neighbour galaxies that show recession velocities similar to the corresponding CIG galaxy are not considered by the CIG isolation criteria as potential companions, which may have a considerable influence on the evolution of the central CIG galaxy. Full Tables 2 and 4 are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/560/A9

PVMirrors: Hybrid PV/CSP collectors that enable lower LCOEs

NASA Astrophysics Data System (ADS)

Fisher, Kate; Yu, Zhengshan Jason; Striling, Rob; Holman, Zachary

2017-06-01

The primary challenge with concentrating solar power (CSP) is that the conversion efficiency is low—and the cost high—compared to that of photovoltaics (PV), and the primary challenge with PV is that the energy generated cannot be stored cost effectively. We introduce a technology that hybridizes CSP and PV, resulting in power plants with high energy conversion efficiency and affordable storage. This is accomplished by replacing silvered troughs (or heliostat facets) with "PVMirrors" that and direct photons of each wavelength to the converter (PV or thermal) that may best use them. A PVMirror looks like a curved PV module that includes a spectrum-splitting dichroic mirror film; this film, which is the heart of the technology, transmits near-infrared light to the underlying silicon PV cells while reflecting both longer and shorter wavelengths to a thermal absorber tube. This paper investigates the optical performance of dichroic mirror film, the specularity of PVMirrors, and the anticipated levelized cost of energy (LCOE) from a PVMirror power plant. PVMirrors are found to decrease LCOE by more than 15% relative to CSP while retaining full dispatchability.

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

Hacke, P.; Terwilliger, K.; Koch, S.

Three crystalline silicon module designs were distributed in five replicas each to five laboratories for testing according to the IEC 62804 (Committee Draft) system voltage durability qualification test for crystalline silicon photovoltaic (PV) modules. The stress tests were performed in environmental chambers at 60 degrees C, 85% relative humidity, 96 h, and with module nameplate system voltage applied.

Why silicon is and will remain the dominant photovoltaic material

NASA Astrophysics Data System (ADS)

Singh, Rajendra

2009-07-01

Rising demands of energy in emerging economies, coupled with the green house gas emissions related problems around the globe have provided a unique opportunity of exploiting the advantages offered by photovoltaic (PV) systems for green energy electricity generation. Similar to cell phones, power generated by PV systems can reach over two billion people worldwide who have no access to clean energy. Only silicon based PV devices meet the low-cost manufacturing criterion of clean energy conversion (abundance of raw material and no environmental health and safety issues). The use of larger size glass substrates and manufacturing techniques similar to the ones used by the liquid crystal display industry and the large scale manufacturing of amorphous silicon thin films based modules (~ GW per year manufacturing at a single location) can lead to installed PV system cost of $3/Wp. This will open a huge market for grid connected PV systems and related markets. With further research and development, this approach can provide $2/Wp installed PV system costs in the next few years. At this cost level, PV electricity generation is competitive with any other technology, and PV power generation can be a dominant electricity generation technology in the 21st century.

Exploratory Analysis of Marketing and Non-marketing E-cigarette Themes on Twitter

PubMed Central

Han, Sifei

2017-01-01

Electronic cigarettes (e-cigs) have been gaining popularity and have emerged as a controversial tobacco product since their introduction in 2007 in the U.S. The smoke-free aspect of e-cigs renders them less harmful than conventional cigarettes and is one of the main reasons for their use by people who plan to quit smoking. The US food and drug administration (FDA) has introduced new regulations early May 2016 that went into effect on August 8, 2016. Given this important context, in this paper, we report results of a project to identify current themes in e-cig tweets in terms of semantic interpretations of topics generated with topic modeling. Given marketing/advertising tweets constitute almost half of all e-cig tweets, we first build a classifier that identifies marketing and non-marketing tweets based on a hand-built dataset of 1000 tweets. After applying the classifier to a dataset of over a million tweets (collected during 4/2015 – 6/2016), we conduct a preliminary content analysis and run topic models on the two sets of tweets separately after identifying the appropriate numbers of topics using topic coherence. We interpret the results of the topic modeling process by relating topics generated to specific e-cig themes. We also report on themes identified from e-cig tweets generated at particular places (such as schools and churches) for geo-tagged tweets found in our dataset using the GeoNames API. To our knowledge, this is the first effort that employs topic modeling to identify e-cig themes in general and in the context of geo-tagged tweets tied to specific places of interest. PMID:28782062

Endothelial disruptive proinflammatory effects of nicotine and e-cigarette vapor exposures.

PubMed

Schweitzer, Kelly S; Chen, Steven X; Law, Sarah; Van Demark, Mary; Poirier, Christophe; Justice, Matthew J; Hubbard, Walter C; Kim, Elena S; Lai, Xianyin; Wang, Mu; Kranz, William D; Carroll, Clinton J; Ray, Bruce D; Bittman, Robert; Goodpaster, John; Petrache, Irina

2015-07-15

The increased use of inhaled nicotine via e-cigarettes has unknown risks to lung health. Having previously shown that cigarette smoke (CS) extract disrupts the lung microvasculature barrier function by endothelial cell activation and cytoskeletal rearrangement, we investigated the contribution of nicotine in CS or e-cigarettes (e-Cig) to lung endothelial injury. Primary lung microvascular endothelial cells were exposed to nicotine, e-Cig solution, or condensed e-Cig vapor (1-20 mM nicotine) or to nicotine-free CS extract or e-Cig solutions. Compared with nicotine-containing extract, nicotine free-CS extract (10-20%) caused significantly less endothelial permeability as measured with electric cell-substrate impedance sensing. Nicotine exposures triggered dose-dependent loss of endothelial barrier in cultured cell monolayers and rapidly increased lung inflammation and oxidative stress in mice. The endothelial barrier disruptive effects were associated with increased intracellular ceramides, p38 MAPK activation, and myosin light chain (MLC) phosphorylation, and was critically mediated by Rho-activated kinase via inhibition of MLC-phosphatase unit MYPT1. Although nicotine at sufficient concentrations to cause endothelial barrier loss did not trigger cell necrosis, it markedly inhibited cell proliferation. Augmentation of sphingosine-1-phosphate (S1P) signaling via S1P1 improved both endothelial cell proliferation and barrier function during nicotine exposures. Nicotine-independent effects of e-Cig solutions were noted, which may be attributable to acrolein, detected along with propylene glycol, glycerol, and nicotine by NMR, mass spectrometry, and gas chromatography, in both e-Cig solutions and vapor. These results suggest that soluble components of e-Cig, including nicotine, cause dose-dependent loss of lung endothelial barrier function, which is associated with oxidative stress and brisk inflammation.

E-cigarette aerosol exposure can cause craniofacial defects in Xenopus laevis embryos and mammalian neural crest cells

PubMed Central

Kennedy, Allyson E.; Kandalam, Suraj; Olivares-Navarrete, Rene

2017-01-01

Since electronic cigarette (ECIG) introduction to American markets in 2007, vaping has surged in popularity. Many, including women of reproductive age, also believe that ECIG use is safer than traditional tobacco cigarettes and is not hazardous when pregnant. However, there are few studies investigating the effects of ECIG exposure on the developing embryo and nothing is known about potential effects on craniofacial development. Therefore, we have tested the effects of several aerosolized e-cigarette liquids (e-cigAM) in an in vivo craniofacial model, Xenopus laevis, as well as a mammalian neural crest cell line. Results demonstrate that e-cigAM exposure during embryonic development induces a variety of defects, including median facial clefts and midface hypoplasia in two of e-cigAMs tested e-cigAMs. Detailed quantitative analyses of the facial morphology revealed that nicotine is not the main factor in inducing craniofacial defects, but can exacerbate the effects of the other e-liquid components. Additionally, while two different e-cigAMs can have very similar consequences on facial appearances, there are subtle differences that could be due to the differences in e-cigAM components. Further assessment of embryos exposed to these particular e-cigAMs revealed cranial cartilage and muscle defects and a reduction in the blood supply to the face. Finally, the expression of markers for vascular and cartilage differentiation was reduced in a mammalian neural crest cell line corroborating the in vivo effects. Our work is the first to show that ECIG use could pose a potential hazard to the developing embryo and cause craniofacial birth defects. This emphasizes the need for more testing and regulation of this new popular product. PMID:28957438

E-cigarette aerosol exposure can cause craniofacial defects in Xenopus laevis embryos and mammalian neural crest cells.

PubMed

Kennedy, Allyson E; Kandalam, Suraj; Olivares-Navarrete, Rene; Dickinson, Amanda J G

2017-01-01

Since electronic cigarette (ECIG) introduction to American markets in 2007, vaping has surged in popularity. Many, including women of reproductive age, also believe that ECIG use is safer than traditional tobacco cigarettes and is not hazardous when pregnant. However, there are few studies investigating the effects of ECIG exposure on the developing embryo and nothing is known about potential effects on craniofacial development. Therefore, we have tested the effects of several aerosolized e-cigarette liquids (e-cigAM) in an in vivo craniofacial model, Xenopus laevis, as well as a mammalian neural crest cell line. Results demonstrate that e-cigAM exposure during embryonic development induces a variety of defects, including median facial clefts and midface hypoplasia in two of e-cigAMs tested e-cigAMs. Detailed quantitative analyses of the facial morphology revealed that nicotine is not the main factor in inducing craniofacial defects, but can exacerbate the effects of the other e-liquid components. Additionally, while two different e-cigAMs can have very similar consequences on facial appearances, there are subtle differences that could be due to the differences in e-cigAM components. Further assessment of embryos exposed to these particular e-cigAMs revealed cranial cartilage and muscle defects and a reduction in the blood supply to the face. Finally, the expression of markers for vascular and cartilage differentiation was reduced in a mammalian neural crest cell line corroborating the in vivo effects. Our work is the first to show that ECIG use could pose a potential hazard to the developing embryo and cause craniofacial birth defects. This emphasizes the need for more testing and regulation of this new popular product.

Monitoring nicotine intake from e-cigarettes: measurement of parent drug and metabolites in oral fluid and plasma.

PubMed

Papaseit, Esther; Farré, Magí; Graziano, Silvia; Pacifici, Roberta; Pérez-Mañá, Clara; García-Algar, Oscar; Pichini, Simona

2017-03-01

Electronic cigarettes (e-cig) known as electronic nicotine devices recently gained popularity among smokers. Despite many studies investigating their safety and toxicity, few examined the delivery of e-cig-derived nicotine and its metabolites in alternative biological fluids. We performed a randomized, crossover, and controlled clinical trial in nine healthy smokers. Nicotine (NIC), cotinine (COT), and trans-3'-hydroxycotinine (3-HCOT) were measured in plasma and oral fluid by liquid chromatography-tandem mass spectrometry after consumption of two consecutive e-cig administrations or two consecutive tobacco cigarettes. NIC and its metabolites were detected both in oral fluid and plasma following both administration conditions. Concentrations in oral fluid resulted various orders of magnitude higher than those observed in plasma. Oral fluid concentration of tobacco cigarette and e-cig-derived NIC peaked at 15 min after each administration and ranged between 1.0 and 1396 μg/L and from 0.3 to 860 μg/L; those of COT between 52.8 and 110 μg/L and from 33.8 to 94.7 μg/L; and those of 3-HCOT between 12.4 and 23.5 μg/L and from 8.5 to 24.4 μg/L. The oral fluid to plasma concentration ratio of both e-cig- and tobacco cigarette-derived NIC peaked at 15 min after both administrations and correlated with oral fluid NIC concentration. The obtained results support the measurement of NIC and metabolites in oral fluid in the assessment of intake after e-cig use and appear to be a suitable alternative to plasma when monitoring nicotine delivery from e-cig for clinical and toxicological studies.

Exploratory Analysis of Marketing and Non-marketing E-cigarette Themes on Twitter.

PubMed

Han, Sifei; Kavuluru, Ramakanth

2016-11-01

Electronic cigarettes (e-cigs) have been gaining popularity and have emerged as a controversial tobacco product since their introduction in 2007 in the U.S. The smoke-free aspect of e-cigs renders them less harmful than conventional cigarettes and is one of the main reasons for their use by people who plan to quit smoking. The US food and drug administration (FDA) has introduced new regulations early May 2016 that went into effect on August 8, 2016. Given this important context, in this paper, we report results of a project to identify current themes in e-cig tweets in terms of semantic interpretations of topics generated with topic modeling. Given marketing/advertising tweets constitute almost half of all e-cig tweets, we first build a classifier that identifies marketing and non-marketing tweets based on a hand-built dataset of 1000 tweets. After applying the classifier to a dataset of over a million tweets (collected during 4/2015 - 6/2016), we conduct a preliminary content analysis and run topic models on the two sets of tweets separately after identifying the appropriate numbers of topics using topic coherence. We interpret the results of the topic modeling process by relating topics generated to specific e-cig themes. We also report on themes identified from e-cig tweets generated at particular places (such as schools and churches) for geo-tagged tweets found in our dataset using the GeoNames API. To our knowledge, this is the first effort that employs topic modeling to identify e-cig themes in general and in the context of geo-tagged tweets tied to specific places of interest.

Recycling of high purity selenium from CIGS solar cell waste materials

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

Gustafsson, Anna M.K., E-mail: anna.gustafsson@chalmers.se; Foreman, Mark R.StJ.; Ekberg, Christian

Highlights: • A new method for recycling of selenium from CIGS solar cell materials is presented. • Separation of selenium as selenium dioxide after heating in oxygen atmosphere. • Complete selenium separation after oxidation of <63 μm particles at 800 °C for 1 h. • After reduction of selenium dioxide the selenium purity was higher than 99.999 wt%. - Abstract: Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To make CIGS solar cells more competitive, both economically and environmentally, in comparison to other energy sources, methods for recycling are needed. In addition tomore » the generally high price of the material, significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling selenium from CIGS through oxidation at elevated temperatures was therefore examined. During oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals. After oxidation for 1 h at 800 °C all of the selenium was separated from the CIGS material. Two different reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that the studied selenium separation method could be the first step in a recycling process aimed at the complete separation and recovery of high purity elements from CIGS.« less

PV system field experience and reliability

NASA Astrophysics Data System (ADS)

Durand, Steven; Rosenthal, Andrew; Thomas, Mike

1997-02-01

Hybrid power systems consisting of battery inverters coupled with diesel, propane, or gasoline engine-driven electrical generators, and photovoltaic arrays are being used in many remote locations. The potential cost advantages of hybrid systems over simple engine-driven generator systems are causing hybrid systems to be considered for numerous applications including single-family residential, communications, and village power. This paper discusses the various design constraints of such systems and presents one technique for reducing hybrid system losses. The Southwest Technology Development Institute under contract to the National Renewable Energy Laboratory and Sandia National Laboratories has been installing data acquisition systems (DAS) on a number of small and large hybrid PV systems. These systems range from small residential systems (1 kW PV - 7 kW generator), to medium sized systems (10 kW PV - 20 kW generator), to larger systems (100 kW PV - 200 kW generator). Even larger systems are being installed with hundreds of kilowatts of PV modules, multiple wind machines, and larger diesel generators.

Detection and location of fouling on photovoltaic panels using a drone-mounted infrared thermography system

NASA Astrophysics Data System (ADS)

Zhang, Peng; Zhang, Lifu; Wu, Taixia; Zhang, Hongming; Sun, Xuejian

2017-01-01

Due to weathering and external forces, solar panels are subject to fouling and defects after a certain amount of time in service. These fouling and defects have direct adverse consequences such as low-power efficiency. Because solar power plants usually have large-scale photovoltaic (PV) panels, fast detection and location of fouling and defects across large PV areas are imperative. A drone-mounted infrared thermography system was designed and developed, and its ability to detect rapid fouling on large-scale PV panel systems was investigated. The infrared images were preprocessed using the K neighbor mean filter, and the single PV module on each image was recognized and extracted. Combining the local and global detection method, suspicious sites were located precisely. The results showed the flexible drone-mounted infrared thermography system to have a strong ability to detect the presence and determine the position of PV fouling. Drone-mounted infrared thermography also has good technical feasibility and practical value in the detection of PV fouling detection.

Prefrontal Parvalbumin Neurons in Control of Attention

PubMed Central

Kim, Hoseok; Ährlund-Richter, Sofie; Wang, Xinming; Deisseroth, Karl; Carlén, Marie

2016-01-01

Summary While signatures of attention have been extensively studied in sensory systems, the neural sources and computations responsible for top-down control of attention are largely unknown. Using chronic recordings in mice, we found that fast-spiking parvalbumin (FS-PV) interneurons in medial prefrontal cortex (mPFC) uniformly show increased and sustained firing during goal-driven attentional processing, correlating to the level of attention. Elevated activity of FS-PV neurons on the timescale of seconds predicted successful execution of behavior. Successful allocation of attention was characterized by strong synchronization of FS-PV neurons, increased gamma oscillations, and phase locking of pyramidal firing. Phase-locked pyramidal neurons showed gamma-phase-dependent rate modulation during successful attentional processing. Optogenetic silencing of FS-PV neurons deteriorated attentional processing, while optogenetic synchronization of FS-PV neurons at gamma frequencies had pro-cognitive effects and improved goal-directed behavior. FS-PV neurons thus act as a functional unit coordinating the activity in the local mPFC circuit during goal-driven attentional processing. PMID:26771492

Progress of the PV Technology Incubator Project Towards an Enhanced U.S. Manufacturing Base

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

Ullal, H.; Mitchell, R.; Keyes, B.

In this paper, we report on the major accomplishments of the U.S. Department of Energy's (DOE) Solar Energy Technologies Program (SETP) Photovoltaic (PV) Technology Incubator project. The Incubator project facilitates a company's transition from developing a solar cell or PV module prototype to pilot- and large-scale U.S. manufacturing. The project targets small businesses that have demonstrated proof-of-concept devices or processes in the laboratory. Their success supports U.S. Secretary of Energy Steven Chu's SunShot Initiative, which seeks to achieve PV technologies that are cost-competitive without subsidies at large scale with fossil-based energy sources by the end of this decade. The Incubatormore » Project has enhanced U.S. PV manufacturing capacity and created more than 1200 clean energy jobs, resulting in an increase in American economic competitiveness. The investment raised to date by these PV Incubator companies as a result of DOE's $ 59 million investment total nearly $ 1.3 billion.« less

Estimation of PV energy production based on satellite data

NASA Astrophysics Data System (ADS)

Mazurek, G.

2015-09-01

Photovoltaic (PV) technology is an attractive source of power for systems without connection to power grid. Because of seasonal variations of solar radiation, design of such a power system requires careful analysis in order to provide required reliability. In this paper we present results of three-year measurements of experimental PV system located in Poland and based on polycrystalline silicon module. Irradiation values calculated from results of ground measurements have been compared with data from solar radiation databases employ calculations from of satellite observations. Good convergence level of both data sources has been shown, especially during summer. When satellite data from the same time period is available, yearly and monthly production of PV energy can be calculated with 2% and 5% accuracy, respectively. However, monthly production during winter seems to be overestimated, especially in January. Results of this work may be helpful in forecasting performance of similar PV systems in Central Europe and allow to make more precise forecasts of PV system performance than based only on tables with long time averaged values.

Defining Threshold Values of Encapsulant and Backsheet Adhesion for PV Module Reliability

DOE PAGES

Bosco, Nick; Eafanti, Joshua; Kurtz, Sarah; ...

2017-10-04

The width-tapered cantilever beam method is used to quantify the debond energy (adhesion) of encapsulant and backsheet structures of 32 modules collected from the field. The collected population of modules contains both those that have remained intact and those with instances of either or both encapsulant and backsheet delamination. From this survey, initial threshold values (an adhesion value above which a module should remain intact throughout its lifetime) for encapsulant and backsheet interfaces are proposed. For encapsulants this value is ~ 160J/m 2 and for backsheets ~ 10J/m 2. Here, it is expected that these values will continue to bemore » refined and evolve as the width-tapered cantilever beam method gets adopted by the PV industry, and that they may aid in the future improvement of accelerated lifetime tests and the development of new, low-cost materials.« less

Defining Threshold Values of Encapsulant and Backsheet Adhesion for PV Module Reliability: Preprint

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

Bosco, Nicholas S; Kurtz, Sarah; Eafanti, Joshua

2017-08-28

The width-tapered cantilever beam method is used to quantify the debond energy (adhesion) of encapsulant and backsheet structures of 27 modules collected from the field. The collected population of modules contains both those that have remained in-tact and those with instances of either or both encapsulant and backsheet delamination. From this survey, initial threshold values (an adhesion value above which a module should remain intact throughout its lifetime) for encapsulant and backsheet interfaces are proposed. For encapsulants this value is about 60 J/m2 and for backsheets about 20 J/m2. It is expected that these values will continue to be refinedmore » and evolve as the width-tapered cantilever beam method becomes adopted by the PV industry, and that they may aid in the future improvement of accelerated lifetime tests and the development of new, low-cost materials.« less

Comparison between two photovoltaic module models based on transistors

NASA Astrophysics Data System (ADS)

Saint-Eve, Frédéric; Sawicki, Jean-Paul; Petit, Pierre; Maufay, Fabrice; Aillerie, Michel

2018-05-01

The main objective of this paper is to verify the possibility to reduce to a simple electronic circuit with very few components the behavior simulation of an un-shaded photovoltaic (PV) module. Particularly, two models based on well-tried elementary structures, i.e., the Darlington structure in first model and the voltage regulation with programmable Zener diode in the second are analyzed. Specifications extracted from the behavior of a real I-V characteristic of a panel are considered and the principal electrical variables are deduced. The two models are expected to match with open circuit voltage, maximum power point (MPP) and short circuit current, without forgetting realistic current slopes on the both sides of MPP. The robustness is mentioned when irradiance varies and is considered as an additional fundamental property. For both models, two simulations are done to identify influence of some parameters. In the first model, a parameter allowing to adjust current slope on left side of MPP proves to be also important for the calculation of open circuit voltage. Besides this model does not authorize an entirely adjustment of I-V characteristic and MPP moves significantly away from real value when irradiance increases. On the contrary, the second model seems to have only qualities: open circuit voltage is easy to calculate, current slopes are realistic and there is perhaps a good robustness when irradiance variations are simulated by adjusting short circuit current of PV module. We have shown that these two simplified models are expected to make reliable and easier simulations of complex PV architecture integrating many different devices like PV modules or other renewable energy sources and storage capacities coupled in parallel association.

Method of junction formation for CIGS photovoltaic devices

DOEpatents

Delahoy, Alan E.

2006-03-28

Sulfur is used to improve the performance of CIGS devices prepared by the evaporation of a single source ZIS type compound to form a buffer layer on the CIGS. The sulfur may be evaporated, or contained in the ZIS type material, or both. Vacuum evaporation apparatus of many types useful in the practice of the invention are known in the art. Other methods of delivery, such as sputtering, or application of a thiourea solution, may be substituted for evaporation.

Method of junction formation for CIGS photovoltaic devices

DOEpatents

Delahoy, Alan E.

2010-01-26

Sulfur is used to improve the performance of CIGS devices prepared by the evaporation of a single source ZIS type compound to form a buffer layer on the CIGS. The sulfur may be evaporated, or contained in the ZIS type material, or both. Vacuum evaporation apparatus of many types useful in the practice of the invention are known in the art. Other methods of delivery, such as sputtering, or application of a thiourea solution, may be substituted for evaporation.

Interplay between Clinical Guidelines and Organizational Workflow Systems. Experience from the MobiGuide Project.

PubMed

Shabo, Amnon; Peleg, Mor; Parimbelli, Enea; Quaglini, Silvana; Napolitano, Carlo

2016-12-07

Implementing a decision-support system within a healthcare organization requires integration of clinical domain knowledge with resource constraints. Computer-interpretable guidelines (CIG) are excellent instruments for addressing clinical aspects while business process management (BPM) languages and Workflow (Wf) engines manage the logistic organizational constraints. Our objective is the orchestration of all the relevant factors needed for a successful execution of patient's care pathways, especially when spanning the continuum of care, from acute to community or home care. We considered three strategies for integrating CIGs with organizational workflows: extending the CIG or BPM languages and their engines, or creating an interplay between them. We used the interplay approach to implement a set of use cases arising from a CIG implementation in the domain of Atrial Fibrillation. To provide a more scalable and standards-based solution, we explored the use of Cross-Enterprise Document Workflow Integration Profile. We describe our proof-of-concept implementation of five use cases. We utilized the Personal Health Record of the MobiGuide project to implement a loosely-coupled approach between the Activiti BPM engine and the Picard CIG engine. Changes in the PHR were detected by polling. IHE profiles were used to develop workflow documents that orchestrate cross-enterprise execution of cardioversion. Interplay between CIG and BPM engines can support orchestration of care flows within organizational settings.

Bandgap Engineering of Cu(In 1-xGax)Se 2 Absorber Layers Fabricated using CuInSe 2 and CuGaSe 2 Targets for One-Step Sputtering Process

DOE PAGES

Park, Jae -Cheol; Lee, Jeon -Ryang; Al-Jassim, Mowafak; ...

2016-10-17

Here we have demonstrated that the bandgap of Cu(In 1-xGa x)Se 2(CIGS) absorber layers was readily controlled by using a one-step sputtering process. CIGS thin-film sample libraries with different Ga/(In + Ga) ratios were synthesized on soda-lime glass at 550 °C using a combinatorial magnetron sputtering system employing CuInSe 2(CIS) and CuGaSe 2(CGS) targets. Energy-dispersive X-ray fluorescence spectrometry (EDS-XRF) confirmed that the CIGS films had different Ga/(In + Ga) ratios, which were varied by the sample configuration on the substrate and ranged from 0.2 to 0.9. X-ray diffraction and Raman spectroscopy revealed that the CIGS films had a pure chalcopyritemore » phase without any secondary phase such as Cu-Se or ordered vacancy compound (OVC), respectively. Furthermore, we found that the optical bandgap energies of the CIGS films determined by transmittance measurements ranged from 1.07 eV to 1.53 eV as the Ga/(In + Ga) ratio increased from 0.2 to 0.9, demonstrating that the one-step sputtering process using CIS and CGS targets is another simple route to control the bandgap energy of the CIGS absorber layer.« less

Impedance-Based Stability Analysis in Grid Interconnection Impact Study Owing to the Increased Adoption of Converter-Interfaced Generators

DOE PAGES

Cho, Youngho; Hur, Kyeon; Kang, Yong; ...

2017-09-08

This study investigates the emerging harmonic stability concerns to be addressed by grid planners in generation interconnection studies, owing to the increased adoption of renewable energy resources connected to the grid via power electronic converters. The wideband and high-frequency electromagnetic transient (EMT) characteristics of these converter-interfaced generators (CIGs) and their interaction with the grid impedance are not accurately captured in the typical dynamic studies conducted by grid planners. This paper thus identifies the desired components to be studied and subsequently develops a practical process for integrating a new CIG into a grid with the existing CIGs. The steps of thismore » process are as follows: the impedance equation of a CIG using its control dynamics and an interface filter to the grid, for example, an LCL filter (inductor-capacitor-inductor type), is developed; an equivalent impedance model including the existing CIGs nearby and the grid observed from the point of common coupling are derived; the system stability for credible operating scenarios is assessed. Detailed EMT simulations validate the accuracy of the impedance models and stability assessment for various connection scenarios. Here, by complementing the conventional EMT simulation studies, the proposed analytical approach enables grid planners to identify critical design parameters for seamlessly integrating a new CIG and ensuring the reliability of the grid.« less

E-cigarettes and flavorings induce inflammatory and pro-senescence responses in oral epithelial cells and periodontal fibroblasts.

PubMed

Sundar, Isaac K; Javed, Fawad; Romanos, Georgios E; Rahman, Irfan

2016-11-22

Electronic-cigarettes (e-cigs) represent a significant and increasing proportion of tobacco product consumption, which may pose an oral health concern. Oxidative/carbonyl stress via protein carbonylation is an important factor in causing inflammation and DNA damage. This results in stress-induced premature senescence (a state of irreversible growth arrest which re-enforces chronic inflammation) in gingival epithelium, which may contribute to the pathogenesis of oral diseases. We show that e-cigs with flavorings cause increased oxidative/carbonyl stress and inflammatory cytokine release in human periodontal ligament fibroblasts, Human Gingival Epithelium Progenitors pooled (HGEPp), and epigingival 3D epithelium. We further show increased levels of prostaglandin-E2 and cycloxygenase-2 are associated with upregulation of the receptor for advanced glycation end products (RAGE) by e-cig exposure-mediated carbonyl stress in gingival epithelium/tissue. Further, e-cigs cause increased oxidative/carbonyl and inflammatory responses, and DNA damage along with histone deacetylase 2 (HDAC2) reduction via RAGE-dependent mechanisms in gingival epithelium. A greater response is elicited by flavored e-cigs. Increased oxidative stress, pro-inflammatory and pro-senescence responses (DNA damage and HDAC2 reduction) can result in dysregulated repair due to proinflammatory and pro-senescence responses in periodontal cells. These data highlight the pathologic role of e-cig aerosol and its flavoring to cells and tissues of the oral cavity in compromised oral health.

Comparative In Vitro Toxicity Profile of Electronic and Tobacco Cigarettes, Smokeless Tobacco and Nicotine Replacement Therapy Products: E-Liquids, Extracts and Collected Aerosols

PubMed Central

Misra, Manoj; Leverette, Robert D.; Cooper, Bethany T.; Bennett, Melanee B.; Brown, Steven E.

2014-01-01

The use of electronic cigarettes (e-cigs) continues to increase worldwide in parallel with accumulating information on their potential toxicity and safety. In this study, an in vitro battery of established assays was used to examine the cytotoxicity, mutagenicity, genotoxicity and inflammatory responses of certain commercial e-cigs and compared to tobacco burning cigarettes, smokeless tobacco (SLT) products and a nicotine replacement therapy (NRT) product. The toxicity evaluation was performed on e-liquids and pad-collected aerosols of e-cigs, pad-collected smoke condensates of tobacco cigarettes and extracts of SLT and NRT products. In all assays, exposures with e-cig liquids and collected aerosols, at the doses tested, showed no significant activity when compared to tobacco burning cigarettes. Results for the e-cigs, with and without nicotine in two evaluated flavor variants, were very similar in all assays, indicating that the presence of nicotine and flavors, at the levels tested, did not induce any cytotoxic, genotoxic or inflammatory effects. The present findings indicate that neither the e-cig liquids and collected aerosols, nor the extracts of the SLT and NRT products produce any meaningful toxic effects in four widely-applied in vitro test systems, in which the conventional cigarette smoke preparations, at comparable exposures, are markedly cytotoxic and genotoxic. PMID:25361047

Cyclin B Proteolysis and the Cyclin-dependent Kinase Inhibitor rum1p Are Required for Pheromone-induced G1 Arrest in Fission Yeast

PubMed Central

Stern, Bodo; Nurse, Paul

1998-01-01

The blocking of G1 progression by fission yeast pheromones requires inhibition of the cyclin-dependent kinase cdc2p associated with the B-cyclins cdc13p and cig2p. We show that cyclosome-mediated degradation of cdc13p and cig2p is necessary for down-regulation of B-cyclin–associated cdc2p kinase activity and for phermone-induced G1 arrest. The cyclin-dependent kinase inhibitor rum1p is also required to maintain this G1 arrest; it binds both cdc13p and cig2p and is specifically required for cdc13p proteolysis. We propose that rum1p acts as an adaptor targeting cdc13p for degradation by the cyclosome. In contrast, the cig2p–cdc2p kinase can be down-regulated, and the cyclin cig2p can be proteolyzed independently of rum1p. We suggest that pheromone signaling inhibits the cig2p–cdc2p kinase, bringing about a transient G1 arrest. As a consequence, rum1p levels increase, thus inhibiting and inducing proteolysis of the cdc13p–cdc2p kinase; this is necessary to maintain G1 arrest. We have also shown that pheromone-induced transcription occurs only in G1 and is independent of rum1p. PMID:9614176

Passivation effect of Cl, F and H atoms on CuIn0.75Ga0.25Se2 (1 1 2) surface

NASA Astrophysics Data System (ADS)

Qi, Rong-fei; Wang, Zhao-hui; Tang, Fu-ling; Agbonkina, Itohan C.; Xue, Hong-tao; Si, Feng-juan; Ma, Sheng-ling; Wang, Xiao-ka

2018-06-01

Using the first-principles calculations within the density functional-theory (DFT) framework, we theoretically investigated the surface reconstruction, surface states near the Fermi level and their passivation on CuIn0.75Ga0.25Se2 (1 1 2) (CIGS) surface by chlorine, fluorine and hydrogen. Surface reconstruction appears on CIG-terminated CIGS (1 1 2) surface and it is a self-passivation. For the locations of Cl, F and H atoms adsorbing on Se-terminated CIGS (1 1 2) surface, four high symmetry adsorption sites: top sites, bridge sites, hexagonal close-packed (hcp) sites and faced centered cubic (fcc) sites were studied respectively. With the coverage of 0.5 monolayer (ML), Cl, F and H adatoms energetically occupy the top sites on the CIGS (112) surface. The corresponding adsorption energies were -2.20 eV, -3.29 eV, -2.60 eV, respectively. The bond length and electronic properties were analyzed. We found that the surface state density near the Fermi level was markedly diminished for 0.5 ML Cl, F and H adsorption on Se-terminated CIGS (1 1 2) surface at top sites. It was also found that H can more efficiently passivate the surface state density than Cl and F atoms, and the effect of adsorption of Cl atoms is better than that of F.

Daily users compared to less frequent users find vape as or more satisfying and less dangerous than cigarettes, and are likelier to use non-cig-alike vaping products.

PubMed

Kozlowski, Lynn T; Homish, D Lynn; Homish, Gregory G

2017-06-01

We assessed the roles of perceived satisfaction and perceived danger and vaping-product-type as correlates of more frequent use of vaping products. In a baseline assessment of a longitudinal study of US Army Reserve/National Guard Soldiers and their partners (New York State, USA, 2014-2016), participants were asked about current use of vaping products (e-cigarettes) and perceived satisfaction and danger in comparison to cigarettes as well as type of product used. Fisher-exact tests and multiple ordinal logistic regressions were used. In multivariable and univariate models, more perceived satisfaction, less perceived danger, and use of non-cig-alike products were associated with more frequent use of vaping products ( p s < 0.05, two-tailed). For self-selected, more frequent adult users, e-cigs can be at least as satisfying as cigarettes and often more satisfying and are perceived as less dangerous than cigarettes. Non-cig-alike products were more likely in daily users. Some concern that e-cigs are a gateway to cigarettes arises from assuming that e-cigs may not be as reinforcing and pleasurable as cigarettes. These results indicate that accurate perception of comparative risk and use of more effective-nicotine delivery product can produce for some users a highly-satisfying alternative to cigarettes.

E-Cigs, Menthol & Dip

MedlinePlus

... Close Search × MENU BACK CLOSE SMOKEFREE.GOV HOME E-Cigs, Menthol & Dip There are many types of tobacco products. Learn how e-cigarettes, menthol cigarettes, smokeless tobacco, and other products ...

An Analysis of the Cost and Performance of Photovoltaic Systems as a Function of Module Area

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

Horowitz, Kelsey A.W.; Fu, Ran; Silverman, Tim

We investigate the potential effects of module area on the cost and performance of photovoltaic systems. Applying a bottom-up methodology, we analyzed the costs associated with mc-Si and thin-film modules and systems as a function of module area. We calculate a potential for savings of up to $0.04/W, $0.10/W, and $0.13/W in module manufacturing costs for mc-Si, CdTe, and CIGS respectively, with large area modules. We also find that an additional $0.05/W savings in balance-of-systems costs may be achieved. However, these savings are dependent on the ability to maintain efficiency and manufacturing yield as area scales. Lifetime energy yield mustmore » also be maintained to realize reductions in the levelized cost of energy. We explore the possible effects of module size on efficiency and energy production, and find that more research is required to understand these issues for each technology. Sensitivity of the $/W cost savings to module efficiency and manufacturing yield is presented. We also discuss non-cost barriers to adoption of large area modules.« less

Controlling morphology and crystallite size of Cu(In{sub 0.7}Ga{sub 0.3})Se{sub 2} nano-crystals synthesized using a heating-up method

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

Hsu, Wei-Hsiang; Hsiang, Hsing-I, E-mail: hsingi@mail.ncku.edu.tw; Chia, Chih-Ta

2013-12-15

CuIn{sub 0.7}Ga{sub 0.3}Se{sub 2}(CIGS) nano-crystals were successfully synthesized via a heating-up process. The non-coordinating solvent (1-octadecene) and selenium/cations ratio effects on the crystalline phase and crystallite size of CIGS nano-crystallites were investigated. It was observed that the CIGS nano-crystallite morphology changed from sheet into spherical shape as the amount of 1-octadecene addition was increased. CIGS nano-crystals were obtained in 9–20 nm sizes as the selenium/cations ratio increased. These results suggest that the monomer reactivity in the solution can be adjusted by changing the solvent type and selenium/cations ratio, hence affecting the crystallite size and distribution. - Graphical abstract: CuIn{sub 0.7}Ga{submore » 0.3}Se{sub 2}(CIGS) nano-crystals were successfully synthesized via a heating-up process in this study. The super-saturation in the solution can be adjusted by changing the OLA/ODE ratio and selenium/cation ratio.« less