WorldWideScience

Sample records for solar selective absorber

  1. Fabrication of high efficacy selective solar absorbers

    Tile, N

    2012-03-01

    Full Text Available High efficiency tandem selective solar absorber materials of carbon in nickel oxide (C-NiO) composite were fabricated on an aluminium substrate using a simple and cost effective sol-gel process. The process involved preparation of carbon and nickel...

  2. Fabrication of selective solar absorbers using pulsed laser deposition

    Yalisi, B

    2009-06-01

    Full Text Available Selective solar absorbers are devices that have been designed to absorb as much as possible of the solar radiation which is in the wavelength range of 0.3 to 2.5 µm and to minimise thermal emittance in the wavelength range from 2.5µm to the far...

  3. Characterization of selective solar absorber under high vacuum.

    Russo, Roberto; Monti, Matteo; di Giamberardino, Francesco; Palmieri, Vittorio G

    2018-05-14

    Total absorption and emission coefficients of selective solar absorbers are measured under high vacuum conditions from room temperature up to stagnation temperature. The sample under investigation is illuminated under vacuum @1000W/m 2 and the sample temperature is recorded during heat up, equilibrium and cool down. During stagnation, the absorber temperature exceeds 300°C without concentration. Data analysis allows evaluating the solar absorptance and thermal emittance at different temperatures. These in turn are useful to predict evacuated solar panel performances at operating conditions.

  4. Selective solar absorber coating research at the CSIR (South Africa)

    Roro, Kittessa T

    2011-05-01

    Full Text Available A sol-gel technique has been established at a laboratory scale for low cost production of high efficient selective solar absorbers comprising a composite material of nano-structured carbon in a nickel oxide matrix. In order for these materials...

  5. Selective solar absorber emittance measurement at elevated temperature

    Giraud, Philémon; Braillon, Julien; Raccurt, Olivier

    2017-06-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The characterization of a material in such condition is complicated and requires advanced apparatuses, and different measurement methods exist for the determination of the two quantities of relevance regarding an absorber, which are its emittance and its solar absorbance. The objective is to develop new optical equipment for measure the emittance of this solar absorber at elevated temperature. In this paper, we present an optical bench developed for emittance measurement on absorbers is conditions of use. Results will be shown, with a discussion of some factors of influence over this measurement and how to control them.

  6. Semiconductor-based Multilayer Selective Solar Absorber for Unconcentrated Solar Thermal Energy Conversion.

    Thomas, Nathan H; Chen, Zhen; Fan, Shanhui; Minnich, Austin J

    2017-07-13

    Solar thermal energy conversion has attracted substantial renewed interest due to its applications in industrial heating, air conditioning, and electricity generation. Achieving stagnation temperatures exceeding 200 °C, pertinent to these technologies, with unconcentrated sunlight requires spectrally selective absorbers with exceptionally low emissivity in the thermal wavelength range and high visible absorptivity for the solar spectrum. In this Communication, we report a semiconductor-based multilayer selective absorber that exploits the sharp drop in optical absorption at the bandgap energy to achieve a measured absorptance of 76% at solar wavelengths and a low emittance of approximately 5% at thermal wavelengths. In field tests, we obtain a peak temperature of 225 °C, comparable to that achieved with state-of-the-art selective surfaces. With straightforward optimization to improve solar absorption, our work shows the potential for unconcentrated solar thermal systems to reach stagnation temperatures exceeding 300 °C, thereby eliminating the need for solar concentrators for mid-temperature solar applications such as supplying process heat.

  7. Large-Scale Nanophotonic Solar Selective Absorbers for High-Efficiency Solar Thermal Energy Conversion.

    Li, Pengfei; Liu, Baoan; Ni, Yizhou; Liew, Kaiyang Kevin; Sze, Jeff; Chen, Shuo; Shen, Sheng

    2015-08-19

    An omnidirectional nanophotonic solar selective absorber is fabricated on a large scale using a template-stripping method. The nanopyramid nickel structure achieves an average absorptance of 95% at a wavelength range below 1.3 μm and a low emittance less than 10% at wavelength >2.5 μm. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Corrosion protection of PVD and paint coatings for selective solar absorber surfaces

    Nunes, A.; Carvalho, M. J.; Diamantino, Teresa C.; Fernandes, J. C. S.

    2015-01-01

    The selective solar absorber surface is a fundamental part of a solar thermal collector, as it is responsible for the solar radiation absorption and for reduction of radiation heat losses. The surface’s optical properties, the solar absorption (á) and the emittance (å), have great impact on the solar thermal collector efficiency. In this work, two coatings types were studied: coatings obtained by physical vapor deposition (PVDs) and coatings obtained by projection with different paints (PCs) ...

  9. Solar radiation absorbing material

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  10. A figure of merit for selective absorbers in flat plate solar water heaters

    Roberts, DE

    2013-12-01

    Full Text Available We derive from first principles an analytical expression for a figure of merit (FM) for a selective solar absorber in a single glazed flat plate water heater. We first show that the efficiency of a collector with an absorber with absorptance α...

  11. Selective paint coatings for coloured solar absorbers: Polyurethane thickness insensitive spectrally selective (TISS) paints (Part II)

    Orel, B.; Spreizer, H.; Surca Vuk, A.; Fir, M. [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Merlini, D.; Vodlan, M. [Color d.d., Cesta komandanta Staneta 4, SI-1230 Medvode (Slovenia); Koehl, M. [Fraunhofer-Institute for Solar Energy Systems ISE, Heidenhofstr. 2, D-79110 Freiburg (Germany)

    2007-01-23

    Red, green and blue paints were prepared for use as thickness insensitive spectrally selective (TISS) paint coatings for solar facade absorbers. The paints were composed of a polyurethane resin binder in which various pigments were incorporated in such a way that they formed stable paint dispersions, satisfying stability criteria for facade coatings. A low emittance of the paints was achieved by using low-emittance aluminium flake pigments combined with iron oxide (red coloured paints). Black pigment was added to adjust solar absorptance. Blue and green paints were made by the addition of coloured aluminium flake pigment and the solar absorptance was also adjusted by the addition of black pigment. Efficiency for photo-thermal conversion of solar radiation was assessed by evaluation of the corresponding performance criteria, which enabled the selection of paints whose performance criteria values were higher than 0 (spectrally non-selective black coating). The results confirmed that blue and green paints and to minor extent red ones, combined selectivity with colour. The morphology of the paints was assessed, revealing that the colours originated from the deposition of finely dispersed colour and/or black pigment on the surface of the aluminium flakes during paint preparation. (author)

  12. Development of optical tools for the characterization of selective solar absorber at elevated temperature

    Giraud, Philemon; Braillon, Julien; Delord, Christine; Raccurt, Olivier

    2016-05-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The objective is to develop new optical equipment for characterization of this solar absorber in condition of use that is to say in air and at elevated temperature. In this paper we present two new optical test benches developed for optical characterization of solar absorbers in condition of use up to 800°C. The first equipment is an integrated sphere with heated sample holder which measures the hemispherical reflectance between 280 and 2500 nm to calculate the solar absorbance at high temperature. The second optical test bench measures the emittance of samples up to 1000°C in the range of 1.25 to 28.57 µm. Results of high temperature measurements on a series of metallic absorbers with selective coating and refractory material for high thermal receiver are presented.

  13. Cermet based solar selective absorbers : further selectivity improvement and developing new fabrication technique

    Nejati, Mohammadreza

    2008-01-01

    Spectral selectivity of cermet based selective absorbers were increased by inducing surface roughness on the surface of the cermet layer using a roughening technique (deposition on hot substrates) or by micro-structuring the metallic substrates before deposition of the absorber coating using laser and imprint structuring techniques. Cu-Al2O3 cermet absorbers with very rough surfaces and excellent selectivity were obtained by employing a roughness template layer under the infrared reflective l...

  14. Computational design for a wide-angle cermet-based solar selective absorber for high temperature applications

    Sakurai, Atsushi; Tanikawa, Hiroya; Yamada, Makoto

    2014-01-01

    The purpose of this study is to computationally design a wide-angle cermet-based solar selective absorber for high temperature applications by using a characteristic matrix method and a genetic algorithm. The present study investigates a solar selective absorber with tungsten–silica (W–SiO 2 ) cermet. Multilayer structures of 1, 2, 3, and 4 layers and a wide range of metal volume fractions are optimized. The predicted radiative properties show good solar performance, i.e., thermal emittances, especially beyond 2 μm, are quite low, in contrast, solar absorptance levels are successfully high with wide angular range, so that solar photons are effectively absorbed and infrared radiative heat loss can be decreased. -- Highlights: • Electromagnetic simulation of radiative properties by characteristic matrix method. • Optimization for multilayered W–SiO 2 cermet-based absorber by a Genetic Algorithm. • We propose a successfully high solar performance of solar selective absorber

  15. Preparation and characterization of CuO nanostructures on copper substrate as selective solar absorbers

    Karthick Kumar, S.; Murugesan, S.; Suresh, S.

    2014-01-01

    Selective solar absorber coatings of copper oxide (CuO) on copper substrates are prepared by room temperature oxidation of copper at different alkaline conditions. The surface morphology and structural analyses of the CuO coatings are carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman spectroscopy techniques. XRD and Raman studies indicated the single phase nature and high crystallinity of the prepared CuO nanostructures. Different CuO nanostructures, viz., nanoneedles, nanofibers and nanoparticles are formed at different alkaline conditions. The influence of reaction time on morphology of the CuO nanostructures is also studied. The thermal emittance values of these nanostructured CuO samples are found to be in the range of 6–7% and their solar absorptances are ranged between 84 and 90%. The observed high solar selectivity values (>12.7) suggest that these coatings can be used as selective absorbers in solar thermal gadgets. - Highlights: • Nanostructured CuO thin films on Cu substrate have been prepared by a facile method. • Morphology of the CuO nanostructures varies with reaction pH. • The thin films show high absorptance in the visible region and low thermal emittance. • Multiple absorption in the porous structure leads to high solar absorptance. • Nanostructures posses solar selectivity values >12

  16. Review of Mid- to High-Temperature Solar Selective Absorber Materials

    Kennedy, C. E.

    2002-07-01

    This report describes the concentrating solar power (CSP) systems using solar absorbers to convert concentrated sunlight to thermal electric power. It is possible to achieve solar absorber surfaces for efficient photothermal conversion having high solar absorptance (a) for solar radiation and a low thermal emittance (e) at the operational temperature. A low reflectance (?'' 0) at wavelengths (?) 3 mm and a high reflectance (?'' 1) at l 3 mm characterize spectrally selective surfaces. The operational temperature ranges of these materials for solar applications can be categorized as low temperature (T< 100 C), mid-temperature (100 C< T< 400 C), and high-temperature (T> 400 C). High- and mid-temperature applications are needed for CSP applications. For CSP applications, the ideal spectrally selective surface would be low-cost and easy to manufacture, chemically and thermally stable in air at elevated operating temperatures (T= 500 C), and have a solar absorptance= 0.98 and a thermal emittance= 0.05 at 500 C.

  17. The CVD ZrB2 as a selective solar absorber

    Randich, E.; Allred, D. D.

    Coatings of ZrB2 and TiB2 for photothermal solar absorber applications were prepared using chemical vapor deposition (CVD) techniques. Oxidation tests suggest a maximum temperature limit for air exposure of 600 K for TiB2 and 800 K for Z4B2. Both materials exhibit innate spectral selectivity with emittance at 375 K ranging from 0.06 to 0.09 and solar absorptance for ZrB2 ranging from 0.67 to 0.77 and solar absorptance for TiB2 ranging from 0.46 to 0.58. ZrB2 has better solar selectivity and more desirable oxidation behavior than TiB2. A 0.071 micrometer antireflection coating of Si3N4 deposited on the ZrB2 coating leads to an increase in absorptance from 0.77 to 0.93, while the emittance remains unchanged.

  18. Chemically vapor-deposited ZrB/sub 2/ as a selective solar absorber

    Randich, E.; Allred, D.D.

    1981-09-25

    Coatings of ZrB/sub 2/ and TiB/sub 2/ for photothermal solar absorber applications were prepared using chemical vapor deposition (CVD) techniques. Oxidation tests suggest a maximum temperature limit for air exposure of 600 K for TiB/sub 2/ and 800 K for ZrB/sub 2/. Both materials exhibit innate spectral selectivity with an emittance at 375 K ranging from 0.06 to 0.09, a solar absorptance for ZrB/sub 2/ ranging from 0.67 to 0.77 and a solar absorptance for TiB/sub 2/ ranging from 0.46 to 0.59. ZrB/sub 2/ has better solar selectivity and more desirable oxidation behavior than TiB/sub 2/. A 0.071 ..mu..m antireflection coating of Si/sub 3/N/sub 4/ deposited onto the ZrB/sub 2/ coating leads to an increase in absorptance from 0.77 to 0.93, while the emittance remains unchanged.

  19. Chemically vapor-deposited ZrB2 as a selective solar absorber

    Randich, E.; Allred, D.D.

    1981-01-01

    Coatings of ZrB 2 and TiB 2 for photothermal solar absorber applications were prepared using chemical vapor deposition (CVD) techniques. Oxidation tests suggest a maximum temperature limit for air exposure of 600 K for TiB 2 and 800 K for ZrB 2 . Both materials exhibit innate spectral selectivity with an emittance at 375 K ranging from 0.06 to 0.09, a solar absorptance for ZrB 2 ranging from 0.67 to 0.77 and a solar absorptance for TiB 2 ranging from 0.46 to 0.59. ZrB 2 has better solar selectivity and more desirable oxidation behavior than TiB 2 . A 0.071 μm antireflection coating of Si 3 N 4 deposited onto the ZrB 2 coating leads to an increase in absorptance from 0.77 to 0.93, while the emittance remains unchanged. (Auth.)

  20. Dependence of the solar absorptance of selective absorber coatings on the angle of incidence

    Reed, K A

    1977-01-01

    The directional solar absorptances ..cap alpha../sub s/(theta) of samples of a number of selective absorber coatings have been determined. The spectral directional hemispherical reflectances plambda(theta;2..pi..) of each sample was measured over the wavelength range 0.3..mu.. to 2.5..mu.. at angles of incidence theta between 10/sup 0/ and 80/sup 0/. The quantity (1-plambda(theta;2..pi..)) was convoluted over an AM2 solar spectrum to obtain ..cap alpha../sub s/(theta) at each angle of incidence. The solar absorptance at near normal incidence varied from sample to sample and from coating to coating, as expected, given the present state of the art. All the absorptances show similar angular dependences, however. When normalized to unity at normal incidence, the data nearly describe a single curve, for which a power series in theta was found. For comparison, the solar absorptance was also determined for freshly prepared lamp black.

  1. Preparation and characterization of porous carbon–titania nanocomposite films as solar selective absorbers

    Cheng, B.; Wang, K.K.; Wang, K.P.; Li, M.; Jiang, W.; Cong, B.J.; Song, C.L.; Jia, S.H.; Han, G.R.; Liu, Y.

    2015-01-01

    Highlights: • The nanocomposites porous C/TiO 2 film were fabricated via PIPS method. • The HRTEM reveals the size of carbon nanoparticles is about 1.1 nm. • The PVP advantages residual carbon content but suppresses its crystallization. • The film exhibits high α (0.928–0.959) with low ε (0.074–0.105) for single layer. - Abstract: Newly proposed selective solar absorbers of porous carbon–titania nanocomposite films with a well-defined interconnected macropores structure were prepared via a polymer-assisted photopolymerization-induced phase-separation method. The microstructure and optical properties of as-deposited nanocomposite films were characterized and discussed in detail. The results show that non-ionic water-soluble polymer polyvinylpyrrolidone works as a sol modifier advantaging the mean size of the interconnected macropores, residual carbon content, and films thickness, but suppresses the order degree of the carbon remained in the films. The high-resolution transmission electron microscopy demonstrated that a small amount of graphite particles with size of around 1.1 nm embedded in the cavity of the porous while the wall of the porous consists of amorphous carbon and titania composites. The single layer of as-prepared porous C/TiO 2 nanocomposite films exhibits high solar absorptance (α = 0.928–0.959) with low thermal emittance (ε = 0.074–0.105), yielding an optimized photothermal conversion efficiency η = α − ε of 0.864 corresponding to a film thickness of around 338 nm, indication of such film is fair enough to serve as an excellent solar absorber

  2. Electrodeposited Ni nanowires-track etched P.E.T. composites as selective solar absorbers

    Lukhwa, R.; Sone, B.; Kotsedi, L.; Madjoe, R.; Maaza, M.

    2018-05-01

    This contribution reports on the structural, optical and morphological properties of nanostructured flexible solar-thermal selective absorber composites for low temperature applications. The candidate material in the system is consisting of electrodeposited nickel nano-cylinders embedded in track-etched polyethylene terephthalate (PET) host membrane of pore sizes ranging between 0.3-0.8µm supported by conductive nickel thin film of about 0.5µm. PET were irradiated with 11MeV/u high charged xenon (Xe) ions at normal incidence. The tubular and metallic structure of the nickel nano-cylinders within the insulator polymeric host forms a typical ceramic-metal nano-composite "Cermet". The produced material was characterized by the following techniques: X-ray diffraction (XRD) for structural characterization to determine preferred crystallographic structure, and grain size of the materials; Scanning electron microscopy (SEM) to determine surface morphology, particle size, and visual imaging of distribution of structures on the surface of the substrate; Atomic force microscopy (AFM) to characterize surface roughness, surface morphology, and film thickness, and UV-Vis-NIR spectrophotometer to measure the reflectance, then to determine solar absorption

  3. Selective solar absorbers: A cost effective solution for access to clean energy in rural Africa

    Katumba, G

    2008-11-01

    Full Text Available by inadequate grid electricity infrastructure. This state of affairs has culminated in massive deforestation and desertification of some parts of Africa. One technology solution is to harness the energy from the sun through solar absorbers. This has applications...

  4. High-Temperature Tolerance in Multi-Scale Cermet Solar-Selective Absorbing Coatings Prepared by Laser Cladding.

    Pang, Xuming; Wei, Qian; Zhou, Jianxin; Ma, Huiyang

    2018-06-19

    In order to achieve cermet-based solar absorber coatings with long-term thermal stability at high temperatures, a novel single-layer, multi-scale TiC-Ni/Mo cermet coating was first prepared using laser cladding technology in atmosphere. The results show that the optical properties of the cermet coatings using laser cladding were much better than the preplaced coating. In addition, the thermal stability of the optical properties for the laser cladding coating were excellent after annealing at 650 °C for 200 h. The solar absorptance and thermal emittance of multi-scale cermet coating were 85% and 4.7% at 650 °C. The results show that multi-scale cermet materials are more suitable for solar-selective absorbing coating. In addition, laser cladding is a new technology that can be used for the preparation of spectrally-selective coatings.

  5. High-Temperature Tolerance in Multi-Scale Cermet Solar-Selective Absorbing Coatings Prepared by Laser Cladding

    Xuming Pang

    2018-06-01

    Full Text Available In order to achieve cermet-based solar absorber coatings with long-term thermal stability at high temperatures, a novel single-layer, multi-scale TiC-Ni/Mo cermet coating was first prepared using laser cladding technology in atmosphere. The results show that the optical properties of the cermet coatings using laser cladding were much better than the preplaced coating. In addition, the thermal stability of the optical properties for the laser cladding coating were excellent after annealing at 650 °C for 200 h. The solar absorptance and thermal emittance of multi-scale cermet coating were 85% and 4.7% at 650 °C. The results show that multi-scale cermet materials are more suitable for solar-selective absorbing coating. In addition, laser cladding is a new technology that can be used for the preparation of spectrally-selective coatings.

  6. High spectral selectivity for solar absorbers using a monolayer transparent conductive oxide coated on a metal substrate

    Shimizu, Makoto; Suzuki, Mari; Iguchi, Fumitada; Yugami, Hiroo

    2017-05-01

    A spectrally selective absorber composed of a monolayer transparent conductive oxide (TCO) coated on a metal substrate is investigated for use in solar systems operating at temperatures higher (>973 K) than the operation temperature of conventional systems ( ˜ 673 K). This method is different from the currently used solar-selective coating technologies, such as those using multilayered and cermet materials. The spectral selective absorption property can be attributed to the inherent optical property of TCO owing to the plasma frequency and interferences between the substrates. Since spectral selectivity can be achieved using monolayered materials, the effect of atomic diffusion occurring at each layer boundary in a multilayer or cermet coatings under high-temperature conditions can be reduced. In addition, since this property is attributed to the inherent property of TCO, the precise control of the layer thickness can be omitted if the layer is sufficiently thick (>0.5 μm). The optimum TCO properties, namely, carrier density and mobility, required for solar-selective absorbers are analyzed to determine the cutoff wavelength and emittance in the infrared range. A solar absorptance of 0.95 and hemispherical emittance of 0.10 at 973 K are needed for achieving the optimum TCO properties, i.e., a carrier density of 5.5 × 1020 cm-3 and mobility of 90 cm2 V-1 s-1 are required. Optical simulations indicate that the spectrally selective absorption weakly depends on the incident angle and film thickness. The thermal stability of the fabricated absorber treated at temperatures up to 973 K for 10 h is verified in vacuum by introducing a SiO2 interlayer, which plays an important role as a diffusion barrier.

  7. Spectrally selective solar absorber with sharp and temperature dependent cut-off based on semiconductor nanowire arrays

    Wang, Yang; Zhou, Lin; Zheng, Qinghui; Lu, Hong; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

    2017-05-01

    Spectrally selective absorbers (SSA) with high selectivity of absorption and sharp cut-off between high absorptivity and low emissivity are critical for efficient solar energy conversion. Here, we report the semiconductor nanowire enabled SSA with not only high absorption selectivity but also temperature dependent sharp absorption cut-off. By taking advantage of the temperature dependent bandgap of semiconductors, we systematically demonstrate that the absorption cut-off profile of the semiconductor-nanowire-based SSA can be flexibly tuned, which is quite different from most of the other SSA reported so far. As an example, silicon nanowire based selective absorbers are fabricated, with the measured absorption efficiency above (below) bandgap ˜97% (15%) combined with an extremely sharp absorption cut-off (transition region ˜200 nm), the sharpest SSA demonstrated so far. The demonstrated semiconductor-nanowire-based SSA can enable a high solar thermal efficiency of ≳86% under a wide range of operating conditions, which would be competitive candidates for the concentrated solar energy utilizations.

  8. Laser nanostructured Co nanocylinders-Al{sub 2}O{sub 3} cermets for enhanced & flexible solar selective absorbers applications

    Karoro, A., E-mail: angela@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Nuru, Z.Y.; Kotsedi, L.; Bouziane, Kh. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Mothudi, B.M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Physics Dept., University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa)

    2015-08-30

    Highlights: • Co-Al{sub 2}O{sub 3} was synthesized by electrodeposition & femtosecond laser structuring. • The ultrafast laser structuring significantly increases the solar absorption. • Co-Al{sub 2}O{sub 3} exhibited 0.98 solar absorptance and 0.03 thermal emittance. - Abstract: We report on the structural and optical properties of laser surface structured Co nanocylinders-Al{sub 2}O{sub 3} cermets on flexible Aluminium substrate for enhanced solar selective absorbers applications. This new family of solar selective absorbers coating consisting of Co nanocylinders embedded into nanoporous alumina template which were produced by standard electrodeposition and thereafter submitted to femtosecond laser surface structuring. While their structural and chemical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and atomic force microscopy, their optical characteristics were investigated by specular & diffuse reflectance. The optimized samples exhibit an elevated optical absorptance α(λ) above 98% and an emittance ε(λ) ∼0.03 in the spectral range of 200–1100 nm. This set of values was suggested to be related to several surface and volume phenomena such as light trapping, plasmon surface effect as well as angular dependence of light reflection induced by the ultrafast laser multi-scale structuring.

  9. Solar energy utilization by solar cells and superblack absorbers

    Bonnet, D; Selders, M

    1975-10-31

    A review is presented of the physical principles responsible for the characteristics of solar cells, with particular reference to Si homojunction and CdS--Cu/sub 2/S thin film devices. Electric power generation from solar cells still appears uncompetitive economically except in special circumstances, but heating from solar energy using selective absorbers with low reemission is more promising.

  10. High performance and thermally stable tandem solar selective absorber coating for concentrated solar thermal power (CSP) application

    Prasad, M. Shiva; Kumar, K. K. Phani; Atchuta, S. R.; Sobha, B.; Sakthivel, S.

    2018-05-01

    A novel tandem absorber system (Mn-Cu-Co-Ox-ZrO2/SiO2) developed on an austenitic stainless steel (SS-304) substrate to show an excellent optical performance (αsol: 0.96; ɛ: 0.23@500 °C). In order to achieve this durable tandem, we experimented with two antireflective layers such as ZrO2-SiO2 and nano SiO2 layer on top of Mn-Cu-Co-Ox-ZrO2 layer. We optimized the thickness of antireflective layers to get good tandem system in terms of solar absorptance and emittance. Field emission scanning electron microscopy (FESEM), UV-Vis-NIR and Fourier transform infrared spectroscopy (FTIR) were used to characterize the developed coatings. Finally, the Mn-Cu-Co-Ox-ZrO2/SiO2 exhibits high temperature resistance up to 800 °C, thus allow an increase in the operating temperature of CSP which may lead to high efficiency. We successfully developed a high temperature resistant tandem layer with easy manufacturability at low cost which is an attractive candidate for concentrated solar power generation (CSP).

  11. Fabrication of MWCNT/NiO nanocomposite thin films for optically selective solar absorbers

    Roro, Kittessa T

    2011-07-01

    Full Text Available = ?T4, ? = 5.67 ? 10-8 W/m2K4 (1) (Stefan-Boltzmann law) 0.1 1 10 0.0 0.2 0.4 0.6 0.8 1.0 S pe ctral rad iatio n (arb . u nits ) Wave length (?m) 0.0 0.2 0.4 0.6 0.8 1.0 Id ea l s el ec tiv e ab so rb er Blackbody... T = 373 K Solar (AM 1.5) Reflectance Fundamentals: Optical Selectivity The power density ,P, of thermal radiation emitted by a black body of temperature T is P = ?T4, ? = 5.67 ? 10-8 W/m2K4 (1) (Stefan-Boltzmann law) At T = 80 ?C, from eq. (1...

  12. Fabrication and characterisation of selective solar absorber surfaces prepared by sol-gel technique

    Katumba, G

    2006-07-01

    Full Text Available characterization: The near normal spectral hemispherical reflect- ance, R, of the prepared samples was measured in the wavelength interval 0.3 to 20.0 μm1 using a Lambda 900 spec- trophotometer and a Bomem-Michel- son 110 FTIR spectrometer. Solar ab...

  13. Development of solar selective absorber layers on aluminium. Final report; Entwicklung solarselektiver Absorberschichten auf Aluminium fuer Solarkollektoren. Abschlussbericht

    Hoenicke, D.; Moeller, T.; Schwarz, T.

    1998-01-31

    A new electrolytic process was developed to form solar selective layers on aluminium. In the developed process, both the formation of the alumina layer and the deposition of metals into the layer takes place in only one treatment step using a single electrolysis bath. The main step of the so called ISOC-method (impulse structured oxide ceramic) is the anodic oxidation of aluminium which was carried out by using a pulse technique at different voltages. During the anodic polarisation a thin alumina ceramic layer was formed, while the cathodic led to the metal deposition as copper and nickel. The conditions of the electrolysis were varied in order to estimate optimal parameters achieving solar selective layers with high selectivity. Furthermore, a scale-up of the lab scale apparatus to a mini plant was carried out. Finally, the corrosion resistance of the absorber layers was improved by the formation of a thin hydrophobic overlayer using a sol-gel treatment. (orig.) [Deutsch] Ein neuartiges Behandlungsverfahren zur Erzeugung von solarselektiven Absorberschichten auf Aluminium wurde entwickelt. Bei dieser elektrochemischen Behandlung wird in einem Einstufenprozess mit einem Elektrolyten durch eine Kombination von anodischer Oxidation und bipolarer Pulsbehandlung auf der Oberflaeche des Aluminiums eine impulsstrukturierte Oxidkeramik (ISOK) erzeugt. Dabei entsteht durch eine anodische Oxidation eine strukturierte Aluminiumoxidschicht. Bei der bipolaren Pulsbehandlung erfolgt dann eine Abscheidung der im ISOK-Elektrolyten befindlichen Metalle Cu und Ni auf oder in die Aluminiumoxidoberflaeche. Die ISOK-Behandlung wurde vom Labormassstab zu einem ISOK-Verfahren im Miniplant-Massstab entwickelt. Der Einfluss der elektrischen Parameter und der chemischen Zusammensetzung der ISOK-Elektrolyte wurde untersucht. Durch eine auf das ISOK-Verfahren abgestimmte Nachbehandlung, ein Tauchverfahren in einer Sol-Gel-Loesung, entsteht ein Schichtsystem mit hoher Solarselektivitaet

  14. Synthesis and optical characterization of C-SiO2 and C-NiO sol-gel composite films for use as selective solar absorbers

    Makiwa, G

    2008-08-01

    Full Text Available The authors present a cheaper and environmentally friendly method to fabricate efficient spectrally selective solar absorber materials. The sol-gel technique was used to fabricate carbon-silica (C-SiO2) and carbon-nickel oxide (C-NiO) composite...

  15. Scalable, "Dip-and-Dry" Fabrication of a Wide-Angle Plasmonic Selective Absorber for High-Efficiency Solar-Thermal Energy Conversion.

    Mandal, Jyotirmoy; Wang, Derek; Overvig, Adam C; Shi, Norman N; Paley, Daniel; Zangiabadi, Amirali; Cheng, Qian; Barmak, Katayun; Yu, Nanfang; Yang, Yuan

    2017-11-01

    A galvanic-displacement-reaction-based, room-temperature "dip-and-dry" technique is demonstrated for fabricating selectively solar-absorbing plasmonic-nanoparticle-coated foils (PNFs). The technique, which allows for facile tuning of the PNFs' spectral reflectance to suit different radiative and thermal environments, yields PNFs which exhibit excellent, wide-angle solar absorptance (0.96 at 15°, to 0.97 at 35°, to 0.79 at 80°), and low hemispherical thermal emittance (0.10) without the aid of antireflection coatings. The thermal emittance is on par with those of notable selective solar absorbers (SSAs) in the literature, while the wide-angle solar absorptance surpasses those of previously reported SSAs with comparable optical selectivities. In addition, the PNFs show promising mechanical and thermal stabilities at temperatures of up to 200 °C. Along with the performance of the PNFs, the simplicity, inexpensiveness, and environmental friendliness of the "dip-and-dry" technique makes it an appealing alternative to current methods for fabricating selective solar absorbers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Performance of an absorbing concentrating solar collectors

    Imadojemu, H.

    1990-01-01

    This paper reports on a comparison of the efficiency of an absorbing fluid parabolic trough concentrating solar collector and a traditional concentrating collector that was made. In the absorbing fluid collector, black liquid flows through a glass tube absorber while the same black liquid flows through a selective black coated copper tube absorber while the same black fluid flows through a selective black coated copper tube absorber in the traditional collector. After a careful study of the properties of available black liquids, a mixture of water and black ink was chosen as the black absorbing medium or transfer fluid. In the black liquid glass collector there is a slightly improved efficiency based on beam radiation as a result of the direct absorption process and an increase in the effective transmittance absorptance. At worst the efficiency of this collector equals that of the traditional concentrating collector when the efficiency is based on total radiation. The collector's reflecting surfaces were made of aluminum sheet, parabolic line focus and with cylindrical receivers. The ease of manufacture and reduced cost per unit energy collected, in addition to the clean and pollution free mode of energy conversion, makes it very attractive

  17. A checkerboard selective absorber with excellent spectral selectivity

    Yang, Liu, E-mail: optyang@zju.edu.cn [Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058 (China); School of Electrical, Computer, and Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Mo, Lei; Chen, Tuo [Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China); Forsberg, Erik [Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058 (China); He, Sailing [Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058 (China); Department of Electromagnetic Engineering, JORCEP, Roy Institute of Technology (KTH), S-100 44 Stockholm (Sweden)

    2015-11-14

    A selective absorber with excellent spectral selectivity is proposed and analyzed. The absorber is based on a germanium (Ge) checkerboard on top of a tantalum (Ta) substrate. At wavelengths shorter than the 1.2 μm cutoff, a very high absorption is achieved due to strong cavity resonances in the Ge nanosquares, and their interactions with adjacent nanocavities and the bottom Ta substrate. At longer wavelengths, absorption is greatly suppressed due to destructive interference between the transparent checkerboard layer and the highly reflective Ta substrate. To better describe the superior selectivity of our configuration, a new figure of merit (FOM) is introduced. We observe a FOM value of 0.88 compared to 0.69 for its planar counterpart. We also conduct a thermal analysis to verify the excellent selectivity of our absorber. A high temperature can be achieved and maintained, promising good potential for applications in solar thermophotovoltaic systems.

  18. The film thickness dependent thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers

    Xiao Xiudi; Xu Gang, E-mail: xiudixiao@163.com; Xiong Bin; Chen Deming; Miao Lei [Chinese Academy of Sciences, Key Laboratory of Renewable Energy and Gas Hydrates, Guangzhou Institute of Energy Conversion (China)

    2012-03-15

    The monolayer Al{sub 2}O{sub 3}:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 Degree-Sign C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al{sub 2}O{sub 3}:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 Degree-Sign C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers.

  19. Microstructured extremely thin absorber solar cells

    Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    In this paper we present the realization of extremely thin absorber (ETA) solar cells employing conductive glass substrates functionalized with TiO2 microstructures produced by embossing. Nanocrystalline or compact TiO2 films on Indium doped tin oxide (ITO) glass substrates were embossed by press......In this paper we present the realization of extremely thin absorber (ETA) solar cells employing conductive glass substrates functionalized with TiO2 microstructures produced by embossing. Nanocrystalline or compact TiO2 films on Indium doped tin oxide (ITO) glass substrates were embossed...

  20. Solar selective absorber functionality of carbon nanoparticles embedded in SiO2, NiO and ZnO matrices

    Katumba, G

    2008-01-01

    Full Text Available It is possible to design an optical material, through control of the substrate and coatings, to absorb a large fraction of the solar spectrum and to emit very little radiation energy in the near and far infra-red wavelength range. This requires a...

  1. Development of an innovative solar absorber

    Goodchild, Gavin

    Solar thermal systems have great potential to replace or reduce the dependence of conventional fossil fuel based heating technologies required for space and water heating. Specifically solar domestic hot water systems can contribute 50-75% of the annual thermal load. To date residential users have been slow to purchase and install systems, primarily due to the large monetary investment required to purchase and install a system. Recent innovations in materials design and manufacturing techniques, offer opportunities for the development of absorber plate designs that have the potential to reduce cost, increase efficiency and reduce payback periods. Consequently, this design study was conducted in conjunction with industrial partners to develop an improved absorber based on roll bond manufacturing that can be produced at reduced cost with comparable or greater thermal efficiency.

  2. Interfacial engineering of solution-processed Ni nanochain-SiO{sub x} (x < 2) cermets towards thermodynamically stable, anti-oxidation solar selective absorbers

    Yu, Xiaobai; Wang, Xiaoxin; Liu, Jifeng, E-mail: Jifeng.Liu@dartmouth.edu [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755 (United States); Zhang, Qinglin [Department of Chemical and Materials Engineering, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506 (United States)

    2016-04-07

    Cermet solar thermal selective absorber coatings are an important component of high-efficiency concentrated solar power (CSP) receivers. The oxidation of the metal nanoparticles in cermet solar absorbers is a great challenge for vacuum-free operation. Recently, we have demonstrated that oxidation is kinetically retarded in solution processed, high-optical-performance Ni nanochain-SiO{sub x} cermet system compared to conventional Ni-Al{sub 2}O{sub 3} system when annealed in air at 450–600 °C for several hours. However, for long-term, high-temperature applications in CSP systems, thermodynamically stable antioxidation behavior is highly desirable, which requires new mechanisms beyond kinetically reducing the oxidation rate. Towards this goal, in this paper, we demonstrate that pre-operation annealing of Ni nanochain-SiO{sub x} cermets at 900 °C in N{sub 2} forms the thermodynamically stable orthorhombic phase of NiSi at the Ni/SiO{sub x} interfaces, leading to self-terminated oxidation at 550 °C in air due to this interfacial engineering. In contrast, pre-operation annealing at a lower temperature of 750 °C in N{sub 2} (as conducted in our previous work) cannot achieve interfacial NiSi formation directly, and further annealing in air at 450–600 °C for >4 h only leads to the formation of the less stable (metastable) hexagonal phase of NiSi. Therefore, the high-temperature pre-operation annealing is critical to form the desirable orthorhombic phase of NiSi at Ni/SiO{sub x} interfaces towards thermodynamically stable antioxidation behavior. Remarkably, with this improved interfacial engineering, the oxidation of 80-nm-diameter Ni nanochain-SiO{sub x} saturates after annealing at 550 °C in air for 12 h. Additional annealing at 550 °C in air for as long as 20 h (i.e., 32 h air annealing at >550 °C in total) has almost no further impact on the structural or optical properties of the coatings, the latter being very sensitive to any

  3. Optical properties of selectively absorbing C/NiO nanocomposite coatings

    Roro, Kittessa T

    2010-12-01

    Full Text Available Nanocomposite thin films are widely used for solar thermal applications. Using carbon nanoparticle containing metal oxide as a spectrally selective solar absorber coating has grown significantly in recent years. Recently, Katumba et al. have...

  4. High temperature solar selective coatings

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  5. High temperature solar energy absorbing surfaces

    Schreyer, J.M.; Schmitt, C.R.; Abbatiello, L.A.

    A solar collector having an improved coating is provided. The coating is a plasma-sprayed coating comprising a material having a melting point above 500/sup 0/C at which it is stable and selected from the group of boron carbide, boron nitride, metals and metal oxides, nitrides, carbides, borides, and silicates. The coatings preferably have a porosity of about 15 to 25% and a thickness of less than 200 micrometers. The coatings can be provided by plasma-spraying particles having a mean diameter of about 10 to 200 micrometers.

  6. Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    Stynes, J. K.; Ihas, B.

    2012-04-01

    As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

  7. Advanced procedure for the assessments of the lifetime of solar absorber coatings

    Köhl, M.; Heck, M.; Brunold, S.; Frei, U.; Carlsson, B.; Möller, K.

    2003-01-01

    New solar absorber coatings are developed and used in advanced collector designs with improved efficiency. The operation temperature as well as the stagnation temperature as the main durability load for the absorbers were increasing during the past due to these innovations. Especially the highly selective new coatings have to suffer by these stronger loads. The service life estimation procedure developed in the framework of research activities of the IEA Solar Heating and Cooling Programme (T...

  8. Robust optimization of a tandem grating solar thermal absorber

    Choi, Jongin; Kim, Mingeon; Kang, Kyeonghwan; Lee, Ikjin; Lee, Bong Jae

    2018-04-01

    Ideal solar thermal absorbers need to have a high value of the spectral absorptance in the broad solar spectrum to utilize the solar radiation effectively. Majority of recent studies about solar thermal absorbers focus on achieving nearly perfect absorption using nanostructures, whose characteristic dimension is smaller than the wavelength of sunlight. However, precise fabrication of such nanostructures is not easy in reality; that is, unavoidable errors always occur to some extent in the dimension of fabricated nanostructures, causing an undesirable deviation of the absorption performance between the designed structure and the actually fabricated one. In order to minimize the variation in the solar absorptance due to the fabrication error, the robust optimization can be performed during the design process. However, the optimization of solar thermal absorber considering all design variables often requires tremendous computational costs to find an optimum combination of design variables with the robustness as well as the high performance. To achieve this goal, we apply the robust optimization using the Kriging method and the genetic algorithm for designing a tandem grating solar absorber. By constructing a surrogate model through the Kriging method, computational cost can be substantially reduced because exact calculation of the performance for every combination of variables is not necessary. Using the surrogate model and the genetic algorithm, we successfully design an effective solar thermal absorber exhibiting a low-level of performance degradation due to the fabrication uncertainty of design variables.

  9. Microstructure and thermal stability of Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coatings

    Meng, Jian-ping; Guo, Rui-rui; Li, Hu; Zhao, Lu-ming; Liu, Xiao-peng; Li, Zhou

    2018-05-01

    Solar selective absorbing coatings play a valuable role in photo-thermal conversion for high efficiency concentrating solar power systems (CSP). In this paper, a novel Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coating was successfully deposited by ion beam assisted deposition. The optical properties, microstructure and element distribution in depth were investigated by spectroscopic ellipsometry, UV-vis-NIR spectrophotometer, transmission electron microscope (TEM) and Auger electron spectroscopy (AES), respectively. A high absorptance of 0.953 and a low thermal emittance of 0.079 at 400 °C are obtained by the integral computation according to the whole reflectance from 300 nm to 28,800 nm. After annealing treatment at 400 °C (in vacuum) for 192 h, the deposited coating exhibits the high thermal stability. Whereas, the photothermal conversion efficiency decreases from 12.10 to 6.86 due to the emittance increase after annealing at 600 °C for 192 h. Meanwhile, the nitrogen atom in the Zr0.3Al0.7N sub-layer diffuses toward the adjacent sub-layer due to the spinodal decomposition of metastable c-ZrAlN and the phase transition from c-AlN to h-AlN, which leads to the composition of the Zr0.3Al0.7N sub-layer deviates the initial design. This phenomenon has a guide effect for the thermal-stability improvement of cermet coatings. Additionally, a serious diffusion between copper and silicon substrate also contributes to the emittance increase.

  10. Excellent solar energy absorbing and retaining fabric material. Chikunetsu hoon sen'i sozai

    Furuta, T. (Unitika Ltd., Osaka (Japan). Central Research Lab.)

    1993-11-10

    Carbides of group IV transition metals such as ZrC, which are used as solar energy selective absorption film for solar energy collectors, has characteristics of absorbing light with a high energy of 0.6eV or more and of converting it to heat when exposed to light, and of not absorbing but reflecting light with a low energy of less than 0.6eV. By using ZrC as fabric materials, therefore, portable and durable heat absorbing and retaining materials can be produced. The authors have developed a solar energy absorbing and retaining fabric material, 'Solar [alpha]' (registered trade mark), which absorbs visible and near infrared rays and converts them to heat, and reflects heat from a human body and confines it. The use of Solar [alpha] has been found in various fields such as clothing as a new material for winter-sportswear, slacks, coats, and swimming suits. In this report, the heat absorbing and retaining mechanisms, basic properties of Solar [alpha], and the results of wearing tests are described. 12 refs., 6 figs., 3 tabs.

  11. Energy Analysis of Solar Collector With perforated Absorber Plate

    Ammar A. Farhan

    2017-09-01

    Full Text Available The thermal performance of three solar collectors with 3, 6 mm and without perforation absorber plate was assessed experimentally. The experimental tests were implemented in Baghdad during the January and February 2017. Five values of airflow rates range between 0.01 – 0.1 m3/s were used through the test with a constant airflow rate during the test day. The variation of the following parameters air temperature difference, useful energy, absorber plate temperature, and collector efficiency was recorded every 15 minutes. The experimental data reports that the increases the number of absorber plate perforations with a small diameter is more efficient rather than increasing the hole diameter of the absorber plate with decreasing the perforation numbers. Maximum air temperature difference throughout the solar collector with 3, 6 mm perforations and without perforations are 17, 15, and 12 oC, respectively. Also, it can be concluded that the energy gained from the solar collector with 3 mm perforation absorber plate is 28.2 % more than the energy gained from solar collector without holes per day for 0.1 m3/s airflow rate. The maximum values of the thermal performance curves are 0.67, 0.64, and 0.56 for the solar collector with 3, 6 mm, and without perforations, respectively.

  12. Absorber design for a Scheffler-Type Solar Concentrator

    Ruelas, José; Palomares, Juan; Pando, Gabriel

    2015-01-01

    Highlights: • Receiver and absorber design methodology based in a solar image in the focal surface. • Stirling absorber dimensions based in a solar image in the focal surface of a STSC. • Comparative study of a solar image in the focal surface from different optical model. • A Monte-Carlo ray-tracing method was used to set STSC cavity receiver aperture. - Abstract: Ray tracing software, digital close range photogrammetry and the Monte-Carlo ray-tracing method have proven to be precise and efficient measurement techniques for the assessment of the shape accuracies of solar concentrators and their components. This paper presents a new method and results for the geometric aspect of a focal image for a Scheffler-Type Solar Concentrator (STSC) using ray tracing, digital close range photogrammetry and the Monte-Carlo ray-tracing method to establish parameters that allow for the design of the most suitable absorber and receiver geometry for coupling the STSC to a Stirling engine. The results of the ray tracing software, digital close range photogrammetry and Monte-Carlo ray tracing technique in STSC are associated with a Stirling receiver. When using the method to perform simulations, we found that the most suitable solar image geometry has an elliptical shape and area of 0.0065 m 2 on average. Although this result is appropriate, the geometry of the receiver is modified to fit an absorber and cavity receiver to improve the heat transfer by radiation

  13. Development of CIGS2 solar cells with lower absorber thickness

    Vasekar, Parag S.; Dhere, Neelkanth G. [Florida Solar Energy Center, University of Central Florida, 1679 Clearlake Rd., Cocoa, FL 32922 (United States); Moutinho, Helio [National Renewable Energy Laboratory, 1617 Cole Blvd. Golden, CO 80401 (United States)

    2009-09-15

    The availability and cost of materials, especially of indium can be a limiting factor as chalcopyrite based thin-film solar cells advance in their commercialization. The required amounts of metals can be lowered by using thinner films. When the thickness of the film decreases, there is possibility of remaining only in the small grain region because the coalescence of grains does not have an opportunity to enhance the grain size to the maximum. Solar cell performance in smaller grain chalcopyrite absorber deteriorates due to larger fraction of grain boundaries. Efforts are being made to reduce the thickness while maintaining the comparable performance. This work presents a study of preparation, morphology and other material properties of CIGS2 absorber layers with decreasing thicknesses up to 1.2 {mu}m and its correlation with the device performance. Encouraging results were obtained demonstrating that reasonable solar cell efficiencies (>10%) can be achieved even for thinner CIGS2 thin-film solar cells. (author)

  14. Design and proof of concept of an innovative very high temperature ceramic solar absorber

    Leray, Cédric; Ferriere, Alain; Toutant, Adrien; Olalde, Gabriel; Peroy, Jean-Yves; Chéreau, Patrick; Ferrato, Marc

    2017-06-01

    Hybrid solar gas-turbine (HSGT) is an attractive technology to foster market penetration of CSP. HSGT offers some major advantages like for example high solar-to-electric conversion efficiency, reduced water requirement and low capital cost. A very high temperature solar receiver is needed when elevated solar share is claimed. A few research works, as reported by Karni et al. [8] and by Buck et al. [1], have been dedicated to solar receiver technologies able to deliver pressurized air at temperature above 750°C. The present work focuses on research aiming at developing an efficient and reliable solar absorber able to provide pressurized air at temperature up to 1000°C and more. A surface absorber technology is selected and a modular design of receiver is proposed in which each absorber module is made of BOOSTEC® SiC ceramic (silicon carbide) as bulk material with straight air channels inside. Early stage experimental works done at CNRS/PROMES on lab-scale absorbers showed that the thermo-mechanical behavior of this material is a critical issue, resulting in elevated probability of failure under severe conditions like large temperature gradient or steep variation of solar flux density in situations of cloud covering. This paper reports on recent progress made at CNRS/PROMES to address this critical issue. The design of the absorber has been revised and optimized according to thermo-mechanical numerical simulations, and an experimental proof of concept has been done on a pilot-scale absorber module at Themis solar tower facility.

  15. Tuning Transpiration by Interfacial Solar Absorber-Leaf Engineering.

    Zhuang, Shendong; Zhou, Lin; Xu, Weichao; Xu, Ning; Hu, Xiaozhen; Li, Xiuqiang; Lv, Guangxin; Zheng, Qinghui; Zhu, Shining; Wang, Zhenlin; Zhu, Jia

    2018-02-01

    Plant transpiration, a process of water movement through a plant and its evaporation from aerial parts especially leaves, consumes a large component of the total continental precipitation (≈48%) and significantly influences global water distribution and climate. To date, various chemical and/or biological explorations have been made to tune the transpiration but with uncertain environmental risks. In recent years, interfacial solar steam/vapor generation is attracting a lot of attention for achieving high energy transfer efficiency. Various optical and thermal designs at the solar absorber-water interface for potential applications in water purification, seawater desalination, and power generation appear. In this work, the concept of interfacial solar vapor generation is extended to tunable plant transpiration by showing for the first time that the transpiration efficiency can also be enhanced or suppressed through engineering the solar absorber-leaf interface. By tuning the solar absorption of membrane in direct touch with green leaf, surface temperature of green leaf will change accordingly because of photothermal effect, thus the transpiration efficiency as well as temperature and relative humidity in the surrounding environment will be tuned. This tunable transpiration by interfacial absorber-leaf engineering can open an alternative avenue to regulate local atmospheric temperature, humidity, and eventually hydrologic cycle.

  16. Spectrally selective solar energy materials

    Sikkens, M.

    1981-01-01

    The performance and properties of spectrally selective materials are considered and, in particular, the selective absorption of solar radiation by free electrons is discussed, both in a homogeneous material in which these electrons are strongly scattered, and in a composite material consisting of small metal particles in a dielectric host. Such materials can be used as selective absorbers if they are deposited as a thin film onto a metal substrate, the latter providing the required low emittance. This type of selective surfaces is produced by reactive sputtering of Ni in an Ar/CH 4 gas mixture. This method can yield Ni films with a considerable carbon concentration. The carbon concentration can be varied over a wide range by adjusting the partial methane pressure. The associated experimental techniques are discussed. As the carbon concentration increases, the structure of the films changes from a Ni phase in which carbon is dissolved, via an intermediate Ni 3 C phase into an amorphous carbon phase with a high electrical resistivity in which small nickel particles are embedded. Both mechanisms of selective absorption by free electrons are observed and are found to be well described by rather simple models. The best selectivity is obtained at high carbon concentrations where the films consist of nickel particles in carbon. Depending on the film thickness and the substrate material, the solar absorptance varies between 0.78 and 0.90, while the thermal emittance varies between 0.025 and 0.04. Since the films are found to be stable at 400 0 C in vacuum, it appears that these films are good candidates for application in photothermal solar energy conversion at temperature levels around 200 0 C and higher. (Auth.)

  17. Water heating solar system using collector with polycarbonate absorber surface

    Souza, Luiz Guilherme Meira de; Sodre, Dilton; Cavalcanti, Eduardo Jose Cidade; Souza, Luiz Guilherme Vieira Meira de; Mendes, Jose Ubiragi de Lima [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)], e-mails: lguilherme@dem.ufrn.br, diltonsodre@ifba.edu.br, ubiragi@ct.ufrn.br

    2010-07-01

    It is presented s solar collector to be used in a heating water for bath system, whose main characteristics are low cost and easy fabrication and assembly processes. The collector absorber surface consists of a polycarbonate plate with an area of 1.5 m{sup 2}. The water inlet and outlet are made of PVC 50mm, and were coupled to a 6mm thick polycarbonate plate using fiberglass resin. A 200 liters thermal reservoir will be used. This reservoir is also alternative. The absorber heating system works under thermo-siphon regimen. Thermal parameters will be evaluated to prove the feasibility of the studied solar heating system to obtain bath water for a four people family. (author)

  18. A high absorbance material for solar collectors' applications

    Oliva, A I; Maldonado, R D; Díaz, E A; Montalvo, A I

    2013-01-01

    In this work, we proposed a low cost material to be used as an excellent absorber for solar collectors, to increase its thermal efficiency by the high capacity to absorb solar radiation. The material, known as 'smoke black' (soot) can be obtained by the incomplete combustion of organic materials, such as the oxygen-acetylene, paraffin, or candles. A comparative analysis between the optical properties (reflectance, absorbance, and emissivity) measured on three covered copper surfaces (without paint, with a commercial matte black paint, and with smoke black) shows amazing optical results for the smoke black. Reflectance values of the smoke black applied over copper surfaces improves 56 times the values obtained from commercial black paints. High values of emissivity (E=0.9988) were measured on the surface covered with smoke black by spectrophotometry in the UV-VIS range, which represents about 7% of increment as compared with the value obtained for commercial black paints (E=0.938). The proposed high absorbance material can be easily applied on any kind of surfaces at low cost.

  19. Effect of different absorbing materials on the performance of basin solar still under Libyan climate conditions

    Shuia, Essaied M.; El-Agouz, Elsayed A.

    2013-01-01

    This experimental study deals with a single-basin solar still using various absorbing materials with and without black painting. Different types of absorbing materials with and without black painting were used to enhance the solar still productivity through improvement in absorptivity. These materials are steel and aluminum with and without black painting and rubber. Two identical solar stills were manufactured using locally available materials. All the results were compared together to reach the best absorbing materials with and without painting that can be used for solar still. it was found that the rubber absorber has the highest water collection during daytime, followed by the black painted steel absorber, then by black painted aluminum absorber and steel without painting absorber. The average enhancement in the daily productivity was about 50% for the rubber absorber compared with the black painted aluminum absorber and about 43% for the rubber absorber compared with the black painted steel absorber.(author)

  20. Solar Biogas Digester with Built-In Reverse Absorber Heater

    Khasan S. Karimov

    2013-01-01

    Full Text Available In this work the design, fabrication and investigation of a solar biogas digester with built-in RAH (Reverse Absorber Heater is presented. The maximum temperature (50 o C inside of the methane tank was taken as a main parameter at the design of the digester. Using energy balance equation for the case of a static mass of fluid being heated; the parameters of thermal insulation of the methane tank were counted. The biogas digester is consisting of methane tank with built-in solar RAH to utilize solar energy for the heating of the slurry prepared from the different organic wastes (dung, sewage, food wastes etc. The methane tank was filled up to 70% of volume by organic wastes of the GIK Institute sewage, firstly, and secondly, by sewage and cow dung as well. During three months (October-December, 2009 and two months (February-March, 2010 the digester was investigated. The solar irradiance incident to the absorber, slurry's temperature and ambient temperature were measured. It was found that using sewage only and sewage with cow dung the retention times was 4 weeks and two weeks respectively and biogas quantity produced was 0.4 and 8.0 m 3 respectively. In addition, biogas upgradation scheme for removal of carbon dioxide, hydrogen sulphide and water vapor from biogas and conversion of biogas energy conversion into electric power is also discussed.

  1. Cu{sub 1.5}Mn{sub 1.5}O{sub 4}-based ceramic spectrally selective coatings for efficient solar absorber applications

    Ma, Pengjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Geng, Qingfen; Gao, Xianghu [Research & Development Center for Eco-material and Eco-chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Yang, Shengrong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Liu, Gang, E-mail: gangliu@licp.cas.cn [Research & Development Center for Eco-material and Eco-chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2016-08-05

    Cu{sub 1.5}Mn{sub 1.5}O{sub 4}-based ceramic spectrally selective (CSS) coating was deposited on aluminum substrate using a sol–gel dip-coating method. The citric acid introduced in the precursor system lowered the required calcining temperature of crystalline Cu{sub 1.5}Mn{sub 1.5}O{sub 4}. X-Ray diffraction (XRD) peaks of coatings annealed above 450 °C were found to coincide exactly with that of crystalline Cu{sub 1.5}Mn{sub 1.5}O{sub 4} in JCPDS database. By optimizing the withdrawal rate and calcining temperature, coating with spectral selectivity as good as α{sub s} = 0.876 and ε{sub 100} = 0.057 was achieved after only one dipping/annealing cycle. Subjected to an accelerated ageing test at 259 °C, the obtained CSS coating showed an excellent thermally durability with the performance criterion (PC) values below 0.05. - Highlights: • Cu{sub 1.5}Mn{sub 1.5}O{sub 4}-based CSS coating is achieved after only one dipping/annealing cycle. • Cu{sub 1.5}Mn{sub 1.5}O{sub 4} coating is obtained as the annealing temperature reaches to 450 °C. • Cu{sub 1.5}Mn{sub 1.5}O{sub 4} coating exhibits optical parameter: α{sub s} = 0.876 and ε{sub 100} = 0.057. • Cu{sub 1.5}Mn{sub 1.5}O{sub 4} coating shows the excellent stability in low to mid temperature region.

  2. Roof Integrated Solar Absorbers: The Measured Performance of ''Invisible'' Solar Collectors: Preprint

    Colon, C. J.; Merrigan, T.

    2001-01-01

    The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory, has investigated the thermal performance of solar absorbers that are an integral, yet indistinguishable, part of a building's roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC's Flexible Roof Facility in Cocoa, Florida, in September 1998. This ''proof-of-concept'' system uses the asphalt shingle roof surface and the plywood decking under the shingles as an unglazed solar absorber. Data was gathered for a one-year period on the system performance. In Phase 2, two more RISA prototypes were constructed and submitted for testing. The first used the asphalt shingles on the roof surface with the tubing mounted on the underside of the plywood decking. The second prototype used metal roofing panels over a plywood substrate and placed the polymer tubing between the plywood decking and the metal roofing. This paper takes a first look at the thermal performance results for the ''invisible'' solar absorbers that use the actual roof surface of a building for solar heat collection

  3. Direct solar steam generation inside evacuated tube absorber

    Khaled M. Bataineh

    2016-12-01

    Full Text Available Direct steam generation by solar radiation falling on absorber tube is studied in this paper. A system of single pipe covered by glass material in which the subcooled undergoes heating and evaporation process is analyzed. Mathematical equations are derived based on energy, momentum and mass balances for system components. A Matlab code is built to simulate the flow of water inside the absorber tube and determine properties of water along the pipe. Widely accepted empirical correlations and mathematical models of turbulent flow, pressure drop for single and multiphase flow, and heat transfer are used in the simulation. The influences of major parameters on the system performance are investigated. The pressure profiles obtained by present numerical solution for each operation condition (3 and 10 MPa matches very well experimental data from the DISS system of Plataforma Solar de Almería. Furthermore, results obtained by simulation model for pressure profiles are closer to the experimental data than those predicted by already existed other numerical model.

  4. Exergy Based Performance Analysis of Double Flow Solar Air Heater with Corrugated Absorber

    S. P. Sharma; Som Nath Saha

    2017-01-01

    This paper presents the performance, based on exergy analysis of double flow solar air heaters with corrugated and flat plate absorber. A mathematical model of double flow solar air heater based on energy balance equations has been presented and the results obtained have been compared with that of a conventional flat-plate solar air heater. The double flow corrugated absorber solar air heater performs thermally better than the flat plate double flow and conventional flat-plate solar air heate...

  5. Improved high temperature solar absorbers for use in Concentrating Solar Power central receiver applications.

    Stechel, Ellen Beth; Ambrosini, Andrea; Hall, Aaron Christopher; Lambert, Timothy L.; Staiger, Chad Lynn; Bencomo, Marlene

    2010-09-01

    Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures >600 C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.05) in the IR region, be stable in air, and be low-cost and readily manufacturable. We propose to utilize solution-based synthesis techniques to prepare intrinsic absorbers for use in central receiver applications.

  6. Emitter/absorber interface of CdTe solar cells

    Song, Tao, E-mail: tsong241@gmail.com; Sites, James R. [Physics Department, Colorado State University, Fort Collins, Colorado 80523 (United States); Kanevce, Ana [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

    2016-06-21

    The performance of CdTe solar cells can be very sensitive to the emitter/absorber interface, especially for high-efficiency cells with high bulk lifetime. Performance losses from acceptor-type interface defects can be significant when interface defect states are located near mid-gap energies. Numerical simulations show that the emitter/absorber band alignment, the emitter doping and thickness, and the defect properties of the interface (i.e., defect density, defect type, and defect energy) can all play significant roles in the interface recombination. In particular, a type I heterojunction with small conduction-band offset (0.1 eV ≤ ΔE{sub C} ≤ 0.3 eV) can help maintain good cell efficiency in spite of high interface defect density, much like with Cu(In,Ga)Se{sub 2} (CIGS) cells. The basic principle is that positive ΔE{sub C}, often referred to as a “spike,” creates an absorber inversion and hence a large hole barrier adjacent to the interface. As a result, the electron-hole recombination is suppressed due to an insufficient hole supply at the interface. A large spike (ΔE{sub C} ≥ 0.4 eV), however, can impede electron transport and lead to a reduction of photocurrent and fill-factor. In contrast to the spike, a “cliff” (ΔE{sub C} < 0 eV) allows high hole concentration in the vicinity of the interface, which will assist interface recombination and result in a reduced open-circuit voltage. Another way to mitigate performance losses due to interface defects is to use a thin and highly doped emitter, which can invert the absorber and form a large hole barrier at the interface. CdS is the most common emitter material used in CdTe solar cells, but the CdS/CdTe interface is in the cliff category and is not favorable from the band-offset perspective. The ΔE{sub C} of other n-type emitter choices, such as (Mg,Zn)O, Cd(S,O), or (Cd,Mg)Te, can be tuned by varying the elemental ratio for an optimal positive value of ΔE{sub C}. These

  7. Aluminium or copper substrate panel for selective absorption of solar energy

    Roberts, M. L.; Sharpe, M. H.; Krupnick, A. C. (Inventor)

    1979-01-01

    A method for making panels which selectively absorb solar energy is disclosed. The panels are comprised of an aluminum substrate, a layer of zinc thereon, a layer of nickel over the zinc layer and an outer layer of solar energy absorbing nickel oxide or a copper substrate with a layer of nickel thereon and a layer of solar energy absorbing nickel oxide distal from the copper substrate.

  8. Development of a Solar Assisted Drying System Using Double-Pass Solar Collector with Finned Absorber

    Azmi, M. S. M.; Othman, M. Y.; Sopian, K.; Ruslan, M. H.; Majid, Z. A. A.; Fudholi, A.; Yasin, J. M.

    2012-09-01

    The Solar Energy Research Group, Universiti Kebangsaan Malaysia, International Islamic University Malaysia and Yayasan FELDA has designed and constructed a solar assisted drying system at OPF FELDA Factory, Felda Bukit Sagu 2, Kuantan, Pahang. The drying system has a total of six double-pass solar collectors. Each collector has a length of 480 cm and a width of 120 cm. The first channel depth is 3.5 cm and the second channel depth is 7 cm. Longitudinal fins made of angle aluminium, 0.8 mm thickness were attached to the bottom surface of the absorber plate. The solar collectors are arranged as two banks of three collectors each in series. Internal manifold are used to connect the collectors. Air enters through the first channel and then through the second channel of the collector. An auxiliary heater source is installed to supply heat under unfavourable solar radiation condition. An on/off controller is used to control the startup and shutdown of the auxiliary heater. An outlet temperature of 70-75 °C can be achieved at solar radiation range of 800-900 W/m2 and flow rate of 0.12 kg/s. The average thermal efficiency of a solar collector is approximately 37%.

  9. Development of a Solar Assisted Drying System Using Double-Pass Solar Collector with Finned Absorber

    Azmi, M S M; Sopian, K; Ruslan, M H; Fudholi, A; Majid, Z A A; Yasin, J M; Othman, M Y

    2012-01-01

    The Solar Energy Research Group, Universiti Kebangsaan Malaysia, International Islamic University Malaysia and Yayasan FELDA has designed and constructed a solar assisted drying system at OPF FELDA Factory, Felda Bukit Sagu 2, Kuantan, Pahang. The drying system has a total of six double-pass solar collectors. Each collector has a length of 480 cm and a width of 120 cm. The first channel depth is 3.5 cm and the second channel depth is 7 cm. Longitudinal fins made of angle aluminium, 0.8 mm thickness were attached to the bottom surface of the absorber plate. The solar collectors are arranged as two banks of three collectors each in series. Internal manifold are used to connect the collectors. Air enters through the first channel and then through the second channel of the collector. An auxiliary heater source is installed to supply heat under unfavourable solar radiation condition. An on/off controller is used to control the startup and shutdown of the auxiliary heater. An outlet temperature of 70–75 °C can be achieved at solar radiation range of 800–900 W/m 2 and flow rate of 0.12 kg/s. The average thermal efficiency of a solar collector is approximately 37%.

  10. Performance Study of Solar Air Heater Having Absorber Plate with Half-Perforated Baffles

    Maheshwari, B. K.; Karwa, Rajendra; Gharai, S. K.

    2011-01-01

    The paper presents a detailed mathematical model for performance prediction of a smooth duct solar air heater validated against the experimental results. Experimental study on a solar air heater having absorber plate with half-perforated baffles on the air flow side shows thermal efficiency enhancement of 28%–45% over that of the smooth duct solar air heater, which is attributed to the heat transfer enhancement (of the order of 180%–235%) due to the perforated baffles attached to the absorber...

  11. CuO-PANI nanostructure with tunable spectral selectivity for solar selective coating application

    Cindrella, L., E-mail: cind@nitt.edu; Prabhu, S., E-mail: sprabhuk@gmail.com

    2016-08-15

    Highlights: • CuO-PANI nanostructure has been reported as the solar selective absorber coating. • Solar selectivity and efficiency of the coatings have been evaluated. • PANI provides a surface texture favourable for multiple reflection. - Abstract: CuO-PANI nanostructure has been demonstrated as the solar selective absorber coating for the first time. The effortless chemical methods and easily scalable techniques such as precipitation, in-situ polymerization and spray coating were adopted for the fabrication of CuO nanorods and CuO-PANI nanostructures for solar application. The synthesis was carried out without using any template. The morphology and phase structure of fabricated CuO nanorods and CuO-PANI nanostructure coatings were studied by atomic force microscopy, scanning electron microscopy and X-ray diffraction analysis. The energy dispersive X-ray spectra and elemental mapping confirm the presence of the chosen elements in the nanostructure. The solar absorptance (α{sub s}), thermal emittance (ε{sub t}) and selectivity (ξ) of the nanostructure coatings on glass substrate were optimized to 0.94, 0.01 and 94 respectively by changing the polyaniline content on the surface of the CuO nanorods. The efficiency of the solar selective coatings were evaluated. The optimized solar absorber coating of CuO-PANI nanostructure is highly promising for its selective optical properties.

  12. Flow distribution in a solar collector panel with horizontally inclined absorber strips

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontally inclined strips. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid...... dynamics (CFD) calculations. Further, experimental investigations of a 12.5 m(2) solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...... rate, properties of solar collector fluid, solar collector fluid inlet temperature and collector tilt angle are shown. The flow distribution through the absorber fins is uniform if high flow rates are used. By decreased flow rate and decreased content of glycol in the glycol/water mixture used as solar...

  13. Imperfectly geometric shapes of nanograting structures as solar absorbers with superior performance for solar cells.

    Nguyen-Huu, Nghia; Cada, Michael; Pištora, Jaromír

    2014-03-10

    The expectation of perfectly geometric shapes of subwavelength grating (SWG) structures such as smoothness of sidewalls and sharp corners and nonexistence of grating defects is not realistic due to micro/nanofabrication processes. This work numerically investigates optical properties of an optimal solar absorber comprising a single-layered silicon (Si) SWG deposited on a finite Si substrate, with a careful consideration given to effects of various types of its imperfect geometry. The absorptance spectra of the solar absorber with different geometric shapes, namely, the grating with attached nanometer-sized features at the top and bottom of sidewalls and periodic defects within four and ten grating periods are investigated comprehensively. It is found that the grating with attached features at the bottom absorbs more energy than both the one at the top and the perfect grating. In addition, it is shown that the grating with defects in each fourth period exhibits the highest average absorptance (91%) compared with that of the grating having defects in each tenth period (89%), the grating with attached features (89%), and the perfect one (86%). Moreover, the results indicate that the absorptance spectrum of the imperfect structures is insensitive to angles of incidence. Furthermore, the absorptance enhancement is clearly demonstrated by computing magnetic field, energy density, and Poynting vector distributions. The results presented in this study prove that imperfect geometries of the nanograting structure display a higher absorptance than the perfect one, and provide such a practical guideline for nanofabrication capabilities necessary to be considered by structure designers.

  14. Selective wave-transmitting electromagnetic absorber through composite metasurface

    Sun, Zhiwei; Zhao, Junming; Zhu, Bo; Jiang, Tian; Feng, Yijun

    2017-11-01

    Selective wave-transmitting absorbers which have one or more narrow transmission bands inside a wide absorption band are often demanded in wireless communication and radome applications for reducing the coupling between different systems, improving anti-jamming capability, and reducing antennas' radar cross section. Here we propose a feasible method that utilizing composite of two metasurfaces with different polarization dependent characteristics, one works as electromagnetic polarization rotator and the other as a wideband polarization dependent electromagnetic wave absorber. The polarization rotator produces a cross polarization output in the wave-transmitting band, while preserves the polarization of the incidence outside the band. The metasurface absorber works for certain linear polarization with a much wider absorption band covering the wave-transmitting frequency. When combining these two metasurfaces properly, the whole structure behaves as a wideband absorber with a certain frequency transmission window. The proposal may be applied in radome designs to reduce the radar cross section of antenna or improving the electromagnetic compatibility in communication devices.

  15. Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation.

    Zhou, Lin; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

    2016-04-01

    The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber-based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m(-2)). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices.

  16. Effect of Collector Aspect Ratio on the Thermal Performance of Wavy Finned Absorber Solar Air Heater

    Abhishek Priyam; Prabha Chand

    2016-01-01

    A theoretical investigation on the effect of collector aspect ratio on the thermal performance of wavy finned absorber solar air heaters has been performed. For the constant collector area, the various performance parameters have been calculated for plane and wavy finned solar air heaters. It has been found that the performance of wavy finned solar air heater improved with the increase in the collector aspect ratio. The performance of wavy finned solar air heater has been found 30 percent hig...

  17. Organometal Halide Perovskite Solar Absorbers and Ferroelectric Nanocomposites for Harvesting Solar Energy

    Hettiarachchi, Chaminda Lakmal

    Organometal halide perovskite absorbers such as methylammonium lead iodide chloride (CH3NH3PbI3-xClx), have emerged as an exciting new material family for photovoltaics due to its appealing features that include suitable direct bandgap with intense light absorbance, band gap tunability, ultra-fast charge carrier generation, slow electron-hole recombination rates, long electron and hole diffusion lengths, microsecond-long balanced carrier mobilities, and ambipolarity. The standard method of preparing CH3NH3PbI3-xClx perovskite precursors is a tedious process involving multiple synthesis steps and, the chemicals being used (hydroiodic acid and methylamine) are quite expensive. This work describes a novel, single-step, simple, and cost-effective solution approach to prepare CH3NH3PbI3-xClx thin films by the direct reaction of the commercially available CH3NH 3Cl (or MACl) and PbI2. A detailed analysis of the structural and optical properties of CH3NH3PbI3-xCl x thin films deposited by aerosol assisted chemical vapor deposition is presented. Optimum growth conditions have been identified. It is shown that the deposited thin films are highly crystalline with intense optical absorbance. Charge carrier separation of these thin films can be enhanced by establishing a local internal electric field that can reduce electron-hole recombination resulting in increased photo current. The intrinsic ferroelectricity in nanoparticles of Barium Titanate (BaTiO3 -BTO) embedded in the solar absorber can generate such an internal field. A hybrid structure of CH3NH 3PbI3-xClx perovskite and ferroelectric BTO nanocomposite FTO/TiO2/CH3NH3PbI3-xClx : BTO/P3HT/Cu as a new type of photovoltaic device is investigated. Aerosol assisted chemical vapor deposition process that is scalable to large-scale manufacturing was used for the growth of the multilayer structure. TiO 2 and P3HT with additives were used as ETL and HTL respectively. The growth process of the solar absorber layer includes the

  18. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-01-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  19. EFFICIENCY OF THE CAPACITY-TYPE SOLAR WATER HEATER WITH THE FLEXIBLE POLYMER ABSORBER.

    Ermuratschii V.V.

    2008-08-01

    Full Text Available Energetic indexes of solar capacity-type water heaters with flexible polymer absorbers and different constructions of enclosures using the refined method of calculus were obtained.

  20. Low-cost solar collectors using thin-film plastics absorbers and glazings

    Wilhelm, W.G.

    1980-01-01

    The design, fabrication, performance, cost, and marketing of flat plate solar collectors using plastic absorbers and glazings are described. Manufacturing cost breakdowns are given for single-glazed and double-glazed collectors. (WHK)

  1. performance Analysis of Different Energy Absorbing Plates on Solar Stills

    H.N. Panchal; P.K. Shah

    2011-01-01

    Solar distillation mimics nature’s hydrologic water cycle by purify water through evaporation as well as condensation. It is one of the most basic purification systems available today to get high quality of drinking water and can remove non-volatile contamination from almost any water source. Solar still is a one kind of solar distillation system in which brackish or impure water converted into drinkable water. Here, three solar stills have developed by locally available materials. The first ...

  2. Intensity and absorbed-power distribution in a cylindrical solar-pumped dye laser

    Williams, M. D.

    1984-01-01

    The internal intensity and absorbed-power distribution of a simplified hypothetical dye laser of cylindrical geometry is calculated. Total absorbed power is also calculated and compared with laboratory measurements of lasing-threshold energy deposition in a dye cell to determine the suitability of solar radiation as a pump source or, alternatively, what modifications, if any, are necessary to the hypothetical system for solar pumping.

  3. Evaluation of Solar Air Heater Performance with Artificial Rib Roughness over the Absorber Plate using Finite Element Modelling Analysis

    Kumar, K. Ravi; Nikhil Varma, P.; Jagadeesh, N.; Sandeep, J. V.; Cheepu, Muralimohan; Venkateswarlu, D.; Srinivas, B.

    2018-03-01

    Among the different renewable energy resources, solar energy is widely used due to its quantitative intensity factor. Solar air heater is cheap, simple in design and has got wide range of applications. A modest solar air heater has a lower in heat transfer and thermal performance as it has heat transfer coefficient lower in between coated absorber plate and the carrier fluid. This low thermal performance can be reduced to a greater extent by introducing the artificially created roughness over the absorber plate of the solar heater. In the present study, the combination of various geometries and roughness’s on the absorber plate are reported. Methods have been developed and implemented in order to improve the rate of the heat transfer. A comparison is drawn among different geometries to select the most effective absorber plate roughness. For flow analysis k-ω SST model was used and the constant heat flux was taken as 1100 W/m2. The Reynolds number is varied in a range from 3000 to 20000. The variation of different parameters temperature, Nusselt number, turbulence kinetic energy and heat transfer coefficient with Reynolds number were examined and discussed.

  4. Analysis of solar water heater with parabolic dish concentrator and conical absorber

    Rajamohan, G.; Kumar, P.; Anwar, M.; Mohanraj, T.

    2017-06-01

    This research focuses on developing novel technique for a solar water heating system. The novel solar system comprises a parabolic dish concentrator, conical absorber and water heater. In this system, the conical absorber tube directly absorbs solar radiation from the sun and the parabolic dish concentrator reflects the solar radiations towards the conical absorber tube from all directions, therefore both radiations would significantly improve the thermal collector efficiency. The working fluid water is stored at the bottom of the absorber tubes. The absorber tubes get heated and increases the temperature of the working fluid inside of the absorber tube and causes the working fluid to partially evaporate. The partially vaporized working fluid moves in the upward direction due to buoyancy effect and enters the heat exchanger. When fresh water passes through the heat exchanger, temperature of the vapour decreases through heat exchange. This leads to condensation of the vapour and forms liquid phase. The working fluid returns to the bottom of the collector absorber tube by gravity. Hence, this will continue as a cyclic process inside the system. The proposed investigation shows an improvement of collector efficiency, enhanced heat transfer and a quality water heating system.

  5. Metamaterial-based integrated plasmonic absorber/emitter for solar thermo-photovoltaic systems

    Wu, Chihhui; Neuner III, Burton; Shvets, Gennady; John, Jeremy; Milder, Andrew; Zollars, Byron; Savoy, Steve

    2012-01-01

    We present the concept of a solar thermo-photovoltaic (STPV) collection system based on a large-area, nanoimprint-patterned film of plasmonic structures acting as an integrated solar absorber/narrow-band thermal emitter (SANTE). The SANTE film concept is based on integrating broad-band solar radiation absorption with selective narrow-band thermal IR radiation which can be efficiently coupled to a photovoltaic (PV) cell for power generation. By employing a low reflectivity refractory metal (e.g., tungsten) as a plasmonic material, we demonstrate that the absorption spectrum of the SANTE film can be designed to be broad-band in the visible range and narrow-band in the infrared range. A detailed balance calculation demonstrates that the total STPV system efficiency exceeds the Shockley–Queisser limit for emitter temperatures above T e = 1200 K, and achieves an efficiency as high as 41% for T e = 2300 K. Emitter temperatures in this range are shown to be achievable under modest sun concentrations (less than 1000 suns) due to the thermal insulation provided by the SANTE film. An experimental demonstration of the wide-angle, frequency-selective absorptivity is presented

  6. The influence of radiative transfer on the turbulent flow inside solar absorbers operating with supercritical CO

    Pecnik, R.; Smit, S.H.H.J.; Patel, A.; Roekaerts, D.J.E.M.

    2016-01-01

    In this paper we investigate and compare two dierent solar receiver technologies for concentrated solar power plants operating with supercritical CO2. The rst receiver is based on conventional surface absorbers, while the second receiver is based on an innovative idea to use volumetric receivers

  7. Preparation and characterization of carbon/nickel oxide nanocomposite coatings for solar absorber applications

    Roro, Kittessa T

    2012-04-01

    Full Text Available Nanocomposite materials have wide range of applications in solar energy conversion. In this work, C/NiO nanocomposite solar energy absorbing surfaces were prepared using sol-gel synthesis and deposited on aluminium substrates using a spin coater...

  8. Superlattice photonic crystal as broadband solar absorber for high temperature operation.

    Rinnerbauer, Veronika; Shen, Yichen; Joannopoulos, John D; Soljačić, Marin; Schäffler, Friedrich; Celanovic, Ivan

    2014-12-15

    A high performance solar absorber using a 2D tantalum superlattice photonic crystal (PhC) is proposed and its design is optimized for high-temperature energy conversion. In contrast to the simple lattice PhC, which is limited by diffraction in the short wavelength range, the superlattice PhC achieves solar absorption over broadband spectral range due to the contribution from two superposed lattices with different cavity radii. The superlattice PhC geometry is tailored to achieve maximum thermal transfer efficiency for a low concentration system of 250 suns at 1500 K reaching 85.0% solar absorptivity. In the high concentration case of 1000 suns, the superlattice PhC absorber achieves a solar absorptivity of 96.2% and a thermal transfer efficiency of 82.9% at 1500 K, amounting to an improvement of 10% and 5%, respectively, versus the simple square lattice PhC absorber. In addition, the performance of the superlattice PhC absorber is studied in a solar thermophotovoltaic system which is optimized to minimize absorber re-emission by reducing the absorber-to-emitter area ratio and using a highly reflective silver aperture.

  9. Optimizing analysis of W-AlN cermet solar absorbing coatings

    Zhang Qichu

    2001-01-01

    The layer thickness and tungsten metal volume fraction of W-AlN cermet solar selective absorbing coatings on a W, Cu or Al infrared reflector with a surface aluminium oxynitride (AlON) or Al 2 O 3 ceramic anti-reflector layer were optimized using physical modelling calculations. Due to limited published data for the refractive index of AlN, and likely oxygen contamination during reactive sputtering of AlN ceramic materials, AlON was used as the ceramic component and the published value of its refractive index was employed. The dielectric function and then the complex refractive index of W-AlON cermet materials were calculated using the Ping Sheng approximation. The downhill simplex method in multi-dimensions was used in the numerical calculation to achieve maximum photo-thermal conversion efficiency at 350 0 C under a concentration factor of 30 for a solar collector tube. Optimization calculation results show that the initial graded (ten-step layers) cermet films all converge to something close to a three-layer film structure, which consists of a low metal volume fraction cermet layer on a high metal volume fraction cermet layer on a metallic infrared reflector with a surface ceramic anti-reflection layer. The optimized three-layer solar coatings have a high solar absorptance of 0.95 for AlON and 0.96 for the Al 2 O 3 anti-reflection layer, and a low hemispherical emittance of 0.073 at 350 deg. C. For the optimized three-layer films the solar radiation is efficiently absorbed internally and by phase interference. Thermal loss is very low for optimized three-layer films due to high reflectance values in the thermal infrared wavelength range and a very sharp edge between low solar reflectance and high thermal infrared reflectance. The high metal volume fraction cermet layer has a metal-like optical behaviour in the thermal infrared wavelength range and makes the largest contribution to the increase of emittance compared with that of the metal infrared reflector

  10. Optimizing analysis of W-AlN cermet solar absorbing coatings

    Zhang Qichu [School of Physics, University of Sydney, NSW (Australia)

    2001-11-07

    The layer thickness and tungsten metal volume fraction of W-AlN cermet solar selective absorbing coatings on a W, Cu or Al infrared reflector with a surface aluminium oxynitride (AlON) or Al{sub 2}O{sub 3} ceramic anti-reflector layer were optimized using physical modelling calculations. Due to limited published data for the refractive index of AlN, and likely oxygen contamination during reactive sputtering of AlN ceramic materials, AlON was used as the ceramic component and the published value of its refractive index was employed. The dielectric function and then the complex refractive index of W-AlON cermet materials were calculated using the Ping Sheng approximation. The downhill simplex method in multi-dimensions was used in the numerical calculation to achieve maximum photo-thermal conversion efficiency at 350{sup 0}C under a concentration factor of 30 for a solar collector tube. Optimization calculation results show that the initial graded (ten-step layers) cermet films all converge to something close to a three-layer film structure, which consists of a low metal volume fraction cermet layer on a high metal volume fraction cermet layer on a metallic infrared reflector with a surface ceramic anti-reflection layer. The optimized three-layer solar coatings have a high solar absorptance of 0.95 for AlON and 0.96 for the Al{sub 2}O{sub 3} anti-reflection layer, and a low hemispherical emittance of 0.073 at 350 deg. C. For the optimized three-layer films the solar radiation is efficiently absorbed internally and by phase interference. Thermal loss is very low for optimized three-layer films due to high reflectance values in the thermal infrared wavelength range and a very sharp edge between low solar reflectance and high thermal infrared reflectance. The high metal volume fraction cermet layer has a metal-like optical behaviour in the thermal infrared wavelength range and makes the largest contribution to the increase of emittance compared with that of the metal

  11. Optimizing analysis of W-AlN cermet solar absorbing coatings

    Qi-Chu Zhang [University of Sydney, NSW (Australia). School of Physics

    2001-11-07

    The layer thickness and tungsten metal volume fraction of W-AlN cermet solar selective absorbing coatings on a W, Cu or Al infrared reflector with a surface aluminium oxynitride (AlON) or Al{sub 2}O{sub 3} ceramic anti-reflector layer were optimized using physical modelling calculations. Due to limited published data for the refractive index of AlN, and likely oxygen contamination during reactive sputtering of AlN ceramic materials, AlON was used as the ceramic component and the published value of its refractive index was employed. The dielectric function and then the complex refractive index of W-AlON cermet materials were calculated using the Ping Sheng approximation. The downhill simplex method in multi-dimensions was used in the numerical calculation to achieve maximum photo-thermal conversion efficiency at 350{sup o}C under a concentration factor of 30 for a solar collector tube. Optimization calculation results show that the initial graded (ten-step layers) cermet films all converge to something close to a three-layer film structure, which consists of a low metal volume fraction cermet layer on a high metal volume fraction cermet layer on a metallic infrared reflector with a surface ceramic anti-reflection layer. The optimized three-layer solar coatings have a high solar absorptance of 0.95 for AlON and 0.96 for the Al{sub 2}O{sub 3} anti-reflection layer, and a low hemispherical emittance of 0.073 at 350{sup o}C. For the optimized three-layer films the solar radiation is efficiently absorbed internally and by phase interference. Thermal loss is very low for optimized three-layer films due to high reflectance values in the thermal infrared wavelength range and a very sharp edge between low solar reflectance and high thermal infrared reflectance. The high metal volume fraction cermet layer has a metal-like optical behaviour in the thermal infrared wavelength range and makes the largest contribution to the increase of emittance compared with that of the metal

  12. PROCESSES OF HEAT-MASS-TRANSFER IN APPARATUS OF SOLAR ABSORBING REFRIGERATION SYSTEMS

    Doroshenko A.V.

    2014-12-01

    Full Text Available Ideology of development of the solar refrigeration systems and systems of air-conditioning, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution, is presented in the article. The processes of joint heat-mass-transfer are considered in the direct and indirect types of evaporated coolers taking into account the phenomenon of re-condensation of aquatic steams at the low temperature evaporated cooling of environments. The pre-liminary analysis of possibilities of the solar systems is executed as it applies in relation to the tasks of cooling of envi-ronments and air-conditioning systems.

  13. Spray pyrolytically grown NiAlOx cermets for solar thermal selective ...

    of the selected sample showed a mixture of nickel and nickel oxide phases with the strong presence of ... ings appear rough, porous, and absorb solar energy; coatings with low ..... inhibited by depositing a protection layer and using a suitable.

  14. Comparison of selective transmitters for solar thermal applications.

    Taylor, Robert A; Hewakuruppu, Yasitha; DeJarnette, Drew; Otanicar, Todd P

    2016-05-10

    Solar thermal collectors are radiative heat exchangers. Their efficacy is dictated predominantly by their absorption of short wavelength solar radiation and, importantly, by their emission of long wavelength thermal radiation. In conventional collector designs, the receiver is coated with a selectively absorbing surface (Black Chrome, TiNOx, etc.), which serves both of these aims. As the leading commercial absorber, TiNOx consists of several thin, vapor deposited layers (of metals and ceramics) on a metal substrate. In this technology, the solar absorption to thermal emission ratio can exceed 20. If a solar system requires an analogous transparent component-one which transmits the full AM1.5 solar spectrum, but reflects long wavelength thermal emission-the technology is much less developed. Bespoke "heat mirrors" are available from optics suppliers at high cost, but the closest mass-produced commercial technology is low-e glass. Low-e glasses are designed for visible light transmission and, as such, they reflect up to 50% of available solar energy. To address this technical gap, this study investigated selected combinations of thin films that could be deposited to serve as transparent, selective solar covers. A comparative numerical analysis of feasible materials and configurations was investigated using a nondimensional metric termed the efficiency factor for selectivity (EFS). This metric is dependent on the operation temperature and solar concentration ratio of the system, so our analysis covered the practical range for these parameters. It was found that thin films of indium tin oxide (ITO) and ZnS-Ag-ZnS provided the highest EFS. Of these, ITO represents the more commercially viable solution for large-scale development. Based on these optimized designs, proof-of-concept ITO depositions were fabricated and compared to commercial depositions. Overall, this study presents a systematic guide for creating a new class of selective, transparent optics for solar

  15. Estimating Solar Irradiation Absorbed by Photovoltaic Panels with Low Concentration Located in Craiova, Romania

    Ionel L. Alboteanu

    2015-03-01

    Full Text Available Solar irradiation is one of the important parameters that should be taken into consideration for the design and utilization of a photovoltaic system. Usually, the input parameters of a photovoltaic system are solar irradiation, the ambient environment temperature and the wind speed, and as a consequence most photovoltaic systems are equipped with sensors for measuring these parameters. This paper presents several mathematical models for solar irradiation assessment. The starting point is represented by the mathematical model of extraterrestrial irradiation, and resulting finally in the model for solar irradiation, absorbed by a low concentration photovoltaic panel. These estimating models of solar irradiation have been particularized for the Craiova, Romania, and have been verified through numerical simulation. Regarding terrestrial solar irradiation, four mathematical models have been adopted, namely Adnot, Haurwitz, Kasten and Empirical (EIM. Of these, the most appropriate for the Craiova location were the models Adnot and Empirical. Consequently, for the calculation of the solar irradiation absorbed by the photovoltaic (PV panels with low concentration, these models have been taken into consideration. In this study, a comparative analysis was also carried out with respect to the solar irradiation absorbed by the PV panels without concentration and those with collectedness of the solar radiation. This analysis was based on the results of numerical simulation and experimental tests.

  16. Multifunctional Solar Systems Based On Two-Stage Regeneration Absorbent Solution

    Doroshenko A.V.

    2015-04-01

    Full Text Available The concepts of multifunctional dehumidification solar systems, heat supply, cooling, and air conditioning based on the open absorption cycle with direct absorbent regeneration developed. The solar systems based on preliminary drainage of current of air and subsequent evaporated cooling. The solar system using evaporative coolers both types (direct and indirect. The principle of two-stage regeneration of absorbent used in the solar systems, it used as the basis of liquid and gas-liquid solar collectors. The main principle solutions are designed for the new generation of gas-liquid solar collectors. Analysis of the heat losses in the gas-liquid solar collectors, due to the mechanism of convection and radiation is made. Optimal cost of gas and liquid, as well as the basic dimensions and configuration of the working channel of the solar collector identified. Heat and mass transfer devices, belonging to the evaporative cooling system based on the interaction between the film and the gas stream and the liquid therein. Multichannel structure of the polymeric materials used to create the tip. Evaporative coolers of water and air both types (direct and indirect are used in the cooling of the solar systems. Preliminary analysis of the possibilities of multifunctional solar absorption systems made reference to problems of cooling media and air conditioning on the basis of experimental data the authors. Designed solar systems feature low power consumption and environmental friendliness.

  17. High-temperature stable absorber coatings for linear concentrating solar thermal power plants; Hochtemperaturstabile Absorberschichten fuer linear konzentrierende solarthermische Kraftwerke

    Hildebrandt, Christina

    2009-03-23

    This work describes the development of new absorber coatings for different applications - para-bolic trough and linear Fresnel collectors - and operating conditions - absorber in vacuum or in air. The demand for higher efficiencies of solar thermal power plants using parabolic trough technology results in higher temperatures in the collectors and on the absorber tubes. As heat losses increase strongly with increasing temperatures, the need for a lower emissivity of the absorber coating at constant absorptivity arises. The linear Fresnel application envisions ab-sorber tubes stable in air at high temperatures of about 450 C, which are to date commercially not available. This work comprises the theoretical background, the modeling and the fabrication of absorber tubes including the technology transfer to a production-size inline sputter coater. In annealing tests and accompanying optical measurements, degradation processes have been observed and specified more precisely by material characterization techniques. The simulations provided the capability of different materials used as potential IR-reflector. The highest selectivity can be achieved by applying silver which consequently has been chosen for the application in absorber coatings of the parabolic trough technology. Thin silver films how-ever need to be stabilized when used at high temperatures. Appropriate barrier layers as well as process and layer parameters were identified. A high selectivity was achieved and stability of the absorber coating for 1200 h at 500 C in vacuum has been demonstrated. For the application in air, silver was also analyzed as a potential IR-reflector. Even though the stability could be increased considerably, it nevertheless proved to be insufficient. The main factors influencing stability in a positive way are the use of higher quality polishing, additional barrier layers and adequate process parameters. This knowledge was applied for developing coatings which are stable in air at

  18. Selection and characterization of new absorbents for carbon dioxide capture

    Ma' mun, Sholeh

    2005-09-01

    Removal of acidic gases, in particular CO2, is an important industrial operation. Carbon dioxide is produced in large quantities by fossil-fuel-fired power plants, steel production, the production of petrochemicals, cement production, and natural gas purification. The global climate change, where CO2 is found to be a major contributor, is one of the most important and challenging environmental issues facing the world community. This has motivated intensive research on CO2 capture and storage. Carbon dioxide capture by an absorption process is one of the most common industrial technologies today. Recent economic studies indicate that the process will also remain competitive in the future. One of the key improvements under development is new, faster and more energy-efficient absorbents. A chemical to be used as a commercial absorbent must have high net cyclic capacity, high absorption rate for CO2 and good chemical stability. Alkanolamines are the most commonly used chemical absorbents for the removal of acidic gases today. In the first part of this thesis, an experimental screening of new absorbents for CO2 capture was performed by absorption of CO2 into both single absorbents and absorbent mixtures for amine-based and non-amine-based systems at 40 deg. Celsius From testing of approx. 30 systems, it was found that an aqueous 30 mass % AEEA (2-(2-aminoethyl-amino)ethanol) solution seems to be a potentially good absorbent for capturing CO2 from atmospheric flue gases. It offers high absorption rate combined with high absorption capacity. In addition toAEEA, MMEA (2-(methylamino)ethanol) also needs to be considered. It could have a good potential when used in contactors where the two phases are separated, like in membrane contactors, whereas indications from the study showed foaming tendencies that will make it difficult to use in ordinary towers. AEEA as the selected absorbent obtained from the screening tests was further investigated to determine its vapor

  19. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL ABSORBER STRIPS

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2007-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal strips. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...... (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...... collector fluid, and by increased collector tilt and inlet temperature, the flow distribution gets worse resulting in a decreased collector efficiency and an increased risk of boiling in the upper part of the collector panel. Keywords: Solar collector; Flow distribution; Computational Fluid Dynamics (CFD...

  20. Comparative technical-economical analysis of solar systems with liquid absorbent

    Kaloyanov, N.; Popova, I.

    2005-01-01

    An analyses of solar water heating systems with two types liquid absorbent is presented. A system with classic collector design is used for comparison. The dependence between the value of the collectors active area and the absorbent type, collectors slope and design parameters is discussed. Two economic indexes (payback period and index of actual net value, based on the electricity price) are used for comparison of the different variants of the system. The presented results shown that: 1) the payback period can be reduced twice if the collectors with liquid absorbent are used; 2) the index of actual net value of the systems using the collectors with fluid absorbent is about four times higher than this one with classic collectors; 3) the systems using distilled water like a liquid absorbent can not fulfil the requirements for the positive economic indicators

  1. ZnO-nanorod arrays for solar cells with extremely thin sulfidic absorber

    Belaidi, A.; Dittrich, Th.; Kieven, D.; Tornow, J.; Schwarzburg, K.; Kunst, M.; Allsop, N.; Lux-Steiner, M.-Ch. [Hahn-Meitner-Institute, Glienicker Str. 100, D-14109 Berlin (Germany); Gavrilov, S. [Moscow Institute of Electronic Technology, 124 498 Moscow (Russian Federation)

    2009-06-15

    Solar cells with an extremely thin sulfidic absorber have been prepared by spray ion layer gas reaction (ILGAR) of In{sub 2}S{sub 3} on ZnO-nanorod arrays. As transparent hole conductor, CuSCN was deposited on the coated ZnO nanorods by impregnation. Surface photovoltage spectroscopy was applied to characterize states contributing to excess carrier generation and charge separation. The charge-selective contact is formed at the In{sub 2}S{sub 3}/CuSCN interface region the states of which also contribute significantly to the photocurrent. The influence of annealing temperature and annealing time of the In{sub 2}S{sub 3}/CuSCN contact region on the open-circuit potential (V{sub OC}), short-circuit current (I{sub SC}) and fill factor (FF) was studied in detail. For solar cells based on ZnO-nanorod arrays (rod length 1.5 {mu}m), efficiency of 2.8% is obtained at AM1.5. (author)

  2. Performance analysis of solar air heater with jet impingement on corrugated absorber plate

    Alsanossi M. Aboghrara

    2017-09-01

    Full Text Available This paper deals with the experimental investigation outlet temperature and efficiency, of Solar Air heater (SAH. The experimental test set up designed and fabricated to study the effect of jet impingement on the corrugated absorber plate, through circular jets in a duct flow of solar air heater, and compared with conventional solar air heater on flat plat absorber. Under effect of mass flow rate (ṁ of air and solar radiation on outlet air temperature, and efficiency, are analyzed. Results show the flow jet impingement on corrugated plat absorber is a strong function of heat transfer enhancement. The present investigation concludes that the mass flow rate of air substantially influences the heat transfer on solar air heaters. And the thermal efficiency of proposed design duct is observed almost 14% more as compare to the smooth duct. At solar radiation 500–1000 (W/M2, 308 K ambient temperature and 0.01–0.03 (Kg/S mass flow rate

  3. Selective optical contacting for solar spectrum management

    Yang, Jianfeng; Chen, Weijian; Wang, Bo; Zhang, Zhilong; Huang, Shujuan; Shrestha, Santosh; Wen, Xiaoming; Patterson, Robert; Conibeer, Gavin

    2017-02-01

    Solar spectrum management using up/down conversion is an important method to improve the photovoltaic energy conversion efficiency. It asks for a monochromatic luminescence absorption at the band edge of the photovoltaic device to reduce both the sub-band-gap and over-band-gap energy losses. Here, we demonstrate an energy selective optical contacting concept to improve the luminescence transfer efficiency for spectrum management. By increasing both the luminescence emission and re-absorption ability through photonic resonance, an efficient photon transfer channel could be established between the luminescence emitter and the photovoltaic component in a near-field region. This concept is not only able to compensate the insufficient band edge absorption ability of the photovoltaic device, but also to break the far-field limitation of luminescence radiation. The energy selection on the optical spectrum naturally imposed by the mode resonance is also helpful to improve the monochromaticity of the luminescence yield. In this paper, a photonic crystal cavity is used to realize the optical contacting concept between a thin silicon film and spectrum converter. The optical power and photon flux transferred between different components are calculated analytically using the electromagnetic Green's function. The corresponding radiative dipole moment is estimated by the fluctuation-dissipation theorem. The example shows an over 80 times enhancement in the luminescence absorbance by the silicon layer, illustrating the great potential of this concept to be applied on nano-structured photovoltaic devices.

  4. Photovoltaic characterization of Copper-Indium-Gallium Sulfide (CIGS2) solar cells for lower absorber thicknesses

    Vasekar, Parag S., E-mail: psvasekar@yahoo.co [Florida Solar Energy Center, 1679 Clearlake Rd., Cocoa FL, 32922 (United States); Jahagirdar, Anant H.; Dhere, Neelkanth G. [Florida Solar Energy Center, 1679 Clearlake Rd., Cocoa FL, 32922 (United States)

    2010-01-31

    Chalcopyrites are important contenders among thin-film solar cells due to their direct band gap and higher absorption coefficient. Copper-Indium-Gallium Sulfide (CIGS2) is a chalcopyrite material with a near-optimum band gap of {approx} 1.5 eV. Record efficiency of 11.99% has been achieved on a 2.7 {mu}m CIGS2 film prepared by sulfurization at the Florida Solar Energy Center (FSEC) PV Materials Lab. In this work, photovoltaic performance analysis has been carried out for a 1.5 {mu}m absorber prepared under similar conditions as that of a 2.7 {mu}m thick absorber sample. It was observed that there is an increase in diode factor and reverse saturation current density when the absorber thickness was decreased. The diode factor increased from 1.69 to 2.18 and reverse saturation current density increased from 1.04 x 10{sup -10} mA/cm{sup 2} to 1.78 x 10{sup -8} mA/cm{sup 2}. This can be attributed to a decrease in the grain size when the absorber thickness is decreased. It was also observed that there is an improvement in the shunt resistance. Improvement in shunt resistance can be attributed to optimized value of i:ZnO for lower absorber thickness and less shunting paths due to a smoother absorber.

  5. Photovoltaic characterization of Copper-Indium-Gallium Sulfide (CIGS2) solar cells for lower absorber thicknesses

    Vasekar, Parag S.; Jahagirdar, Anant H.; Dhere, Neelkanth G.

    2010-01-01

    Chalcopyrites are important contenders among thin-film solar cells due to their direct band gap and higher absorption coefficient. Copper-Indium-Gallium Sulfide (CIGS2) is a chalcopyrite material with a near-optimum band gap of ∼ 1.5 eV. Record efficiency of 11.99% has been achieved on a 2.7 μm CIGS2 film prepared by sulfurization at the Florida Solar Energy Center (FSEC) PV Materials Lab. In this work, photovoltaic performance analysis has been carried out for a 1.5 μm absorber prepared under similar conditions as that of a 2.7 μm thick absorber sample. It was observed that there is an increase in diode factor and reverse saturation current density when the absorber thickness was decreased. The diode factor increased from 1.69 to 2.18 and reverse saturation current density increased from 1.04 x 10 -10 mA/cm 2 to 1.78 x 10 -8 mA/cm 2 . This can be attributed to a decrease in the grain size when the absorber thickness is decreased. It was also observed that there is an improvement in the shunt resistance. Improvement in shunt resistance can be attributed to optimized value of i:ZnO for lower absorber thickness and less shunting paths due to a smoother absorber.

  6. Towards corrosion testing of unglazed solar absorber surfaces in simulated acid rain

    Salo, T.; Pehkonen, A.; Konttinen, P.; Lund, P.

    2005-01-01

    Electrochemical impedance spectroscopy and potentiodynamic polarization tests were utilized for determining corrosion probabilities of unglazed C/Al 2 O 3 /Al solar absorber surfaces in simulated acid rain. Previously, the main degradation mechanism found was exponentially temperature-related hydration of aluminium oxide. In acid rain tests the main corrosion determinant was the pH value of the rain. Results indicate that these methods measure corrosion characteristics of Al substrate instead of the C/Al 2 O 3 /Al surface, probably mainly due to the rough and non-uniform microstructure of the latter. Further analyses of the test methods are required in order to estimate their applicability on Al-based uniform sputtered absorber surfaces. (author) (C/Al 2 O 3 /Al solar absorber; Acid rain; Corrosion; Electrochemical tests)

  7. Environmental standards for thermal solar collectors with particular regard to the selective coatings of the absorber surfaces. Final report; Umweltstandards fuer thermische Solarkollektoren unter besonderer Beruecksichtigung der selektiven Beschichtung ihrer Absorberoberflaechen. Abschlussbericht

    Handke, Volker; Kamburow, Christian

    2008-07-15

    There are only out-dated research results on the environmental impact of solar thermal collectors which do not show the state of the art at the moment in this field. Particularly with regard to the long-term resistance and the ageing there are no current scientific findings. There are controversial findings on the different coating technologies with regard to their energy demand, optical performance, environmental impact and long-term resistance. The research project aims on the development of ambitious technical environmental standards to update the ''Marktanreizprogramm'' (market stimulating programme) in accordance with the European laws and regulations on grants and taking into account the technological and market development. The following methods were used: empirical market analysis with manufacturers interviews, investigation of the cumulated energy demand and EcoIndicator 99 values of different collectors, life cycle analysis of different coating technologies in accordance with ISO 14040-42 and examination of the resistance according to Task 10 of the IEA SHC. The following environmental standards are being proposed: the solar thermal generated heat quantity, compliance with the Task 10 resistance requirements, compliance with EN 12975-12977 and Solar Keymark respectively, compliance with RAL UZ 73 as well as a minimum return of 525 kWh/ m2/ year at a solar coverage ratio of more than 40%. To apply these environmental standards it is being proposed to divide the funding within the ''Marktanreizprogramm'' into a basic funding and a funding based on the performance of the collectors. Prerequisite for receiving the basic funding is the compliance with the environmental standards. The basic funding should be differentiated taking into account the different technologies and applications as well as the competitiveness. Furthermore the basic funding should be a precondition for receiving the performance funding. The

  8. Entropy generation and thermodynamic analysis of solar air heaters with artificial roughness on absorber plate

    Prasad Radha K.

    2017-09-01

    Full Text Available This paper presents mathematical modelling and numerical analysis to evaluate entropy generation analysis (EGA by considering pressure drop and second law efficiency based on thermodynamics for forced convection heat transfer in rectangular duct of a solar air heater with wire as artificial roughness in the form of arc shape geometry on the absorber plate. The investigation includes evaluations of entropy generation, entropy generation number, Bejan number and irreversibilities of roughened as well as smooth absorber plate solar air heaters to compare the relative performances. Furthermore, effects of various roughness parameters and operating parameters on entropy generation have also been investigated. Entropy generation and irreversibilities (exergy destroyed has its minimum value at relative roughness height of 0.0422 and relative angle of attack of 0.33, which leads to the maximum exergetic efficiency. Entropy generation and exergy based analyses can be adopted for the evaluation of the overall performance of solar air heaters.

  9. Unassisted HI photoelectrolysis using n-WSe2 solar absorbers.

    McKone, James R; Potash, Rebecca A; DiSalvo, Francis J; Abruña, Héctor D

    2015-06-07

    Molybdenum and tungsten diselenide are among the most robust and efficient semiconductor materials for photoelectrochemistry, but they have seen limited use for integrated solar energy storage systems. Herein, we report that n-type WSe2 photoelectrodes can facilitate unassisted aqueous HI electrolysis to H2(g) and HI3(aq) when placed in contact with a platinum counter electrode and illuminated by simulated sunlight. Even in strongly acidic electrolyte, the photoelectrodes are robust and operate very near their maximum power point. We have rationalized this behavior by characterizing the n-WSe2|HI/HI3 half cell, the Pt|HI/H2||HI3/HI|Pt full cell, and the n-WSe2 band-edge positions. Importantly, specific interactions between the n-WSe2 surface and aqueous iodide significantly shift the semiconductor's flatband potential and allow for unassisted HI electrolysis. These findings exemplify the important role of interfacial chemical reactivity in influencing the energetics of semiconductor-liquid junctions and the resulting device performance.

  10. Mechanically Robust, Stretchable Solar Absorbers with Submicron-Thick Multilayer Sheets for Wearable and Energy Applications.

    Lee, Hye Jin; Jung, Dae-Han; Kil, Tae-Hyeon; Kim, Sang Hyeon; Lee, Ki-Suk; Baek, Seung-Hyub; Choi, Won Jun; Baik, Jeong Min

    2017-05-31

    A facile method to fabricate a mechanically robust, stretchable solar absorber for stretchable heat generation and an enhanced thermoelectric generator (TEG) is demonstrated. This strategy is very simple: it uses a multilayer film made of titanium and magnesium fluoride optimized by a two-dimensional finite element frequency-domain simulation, followed by the application of mechanical stresses such as bending and stretching to the film. This process produces many microsized sheets with submicron thickness (∼500 nm), showing great adhesion to any substrates such as fabrics and polydimethylsiloxane. It exhibits a quite high light absorption of approximately 85% over a wavelength range of 0.2-4.0 μm. Under 1 sun illumination, the solar absorber on various stretchable substrates increased the substrate temperature to approximately 60 °C, irrespective of various mechanical stresses such as bending, stretching, rubbing, and even washing. The TEG with the absorber on the top surface also showed an enhanced output power of 60%, compared with that without the absorber. With an incident solar radiation flux of 38.3 kW/m 2 , the output power significantly increased to 24 mW/cm 2 because of the increase in the surface temperature to 141 °C.

  11. Thermal Performance Analysis of Staging Effect of Solar Thermal Absorber with Cross Design

    Amir Abdul Razak; Zafri Azran Abdul Majid; Mohd Hafidz Ruslan; Kamaruzzaman Sopian

    2015-01-01

    The type and shape of solar thermal absorber materials will impact on the operating temperature and thermal energy storage effect of a solar air thermal collector. For a standard flat-plate design, energy gain can be increased by expanding the thermal absorber area along the collector plane, subject to area limitation. This paper focuses on the staging effect of a metal hollow square rod absorber of aluminium, stainless steel, and a combination of the two with a cross design, for the heat gain and temperature characteristics of a solar air collector. Experiments were carried out with three cross design set-ups, with 30 minutes of heating and cooling, phase, respectively, under 485 W/ m 2 solar irradiance value, and at a constant air speed at 0.38 m/ s. One set aluminium set-up delivered the highest output temperature of 41.8 degree Celsius, followed by two-sets aluminium and one aluminium set + one stainless steel set at 39.3 and 38.2 degree Celsius, respectively. The lowest peak temperature is recorded on three sets of the aluminium absorber at 35 degree Celsius. The bi-metallic set-up performed better than the two aluminium set-up where each set-up obtained a temperature drop against heat gain gradient value of -0.4186 degree Celsius/ W and -0.4917 degree Celsius/ W, respectively. Results concluded that by increasing the number of sets, the volume and surface areas of the absorber material are also increased, and lead to a decrease in peak temperature output for each increase of sets. (author)

  12. XPS and SIMS characterisation of TiOxNy solar absorber films

    Metson, J.B.; Prince, K.E.; Bittar, A.; Tornquist, J.

    1999-01-01

    Full text: TiO x N y thin films have useful properties as selective solar absorbers when used in tandem with a collector substrate. Such films are transparent across a reasonable window of the solar spectrum, but have low thermal emissivity. They are however limited by their thermal stability under the typical operating conditions they experience. In this study, TiO x N y films have been deposited on Si and Cu substrates using ion beam assisted deposition. The films are amorphous and x and y were controlled by altering the O 2 /N 2 ratio in the gas source. After annealing at temperatures of 200 - 400 deg C, films have been depth profiled using Secondary Ion Mass Spectrometry. Profiles reveal the degradation of the film by migration of the substrate atoms through the films, to the sample surface. In general, films with x 1 show improved stability, ultimately at the expense of a reduced transmission window. Thermal stability is also improved by the use of diffusion barriers either at the substrate film interface or at the surface of the film. However contrary to previous suggestions, the degradation mechanism involves the formation not of an oxide at the film surface but a phase which is nitrogen rich. The nature of this phase, formed by diffusion of the substrate atoms, has been investigated by X-ray photoelectron spectroscopy (XPS). These investigations reveal very complex behaviour in the early stages of film failure, with an almost intact TiO x N y layer surviving, but being progressively buried by the growth of the reaction layer at the film surface. Copyright (1999) Australian X-ray Analytical Association Inc

  13. Influence of an absorbers GEMPEHD thermal properties on the propagation of heat in a solar sensor

    Nassim Baba Ahmed

    2018-01-01

    Full Text Available This paper presents an experimental study to measure some physic-chemical properties of a high-density polyethylene geomembane (GEMPEHD in a temperature range from 300 K to 400 K. The results will yield a dependency between temperature and its properties in order to study an energy and process the thermal aging GEMPEHD on the solar collector. In the energy study, we solve the nonlinear equation of unsteady heat with as main non linearity influence of different properties GEMPEHD on the solar collector and one notes that the GEMPEHD presented a maximum exchange Thermal characterized by high absorption and low reflection. Thus, increasing the power absorbed by the GEMPEHD increases its temperature and the useful power received by the air and then the air temperature. Overall losses increase with the increase of the temperature difference between the GEMPEHD and windows and this increases the efficiency of the solar collector and minimize the entropy of the system. Then the study of thermal aging is dedicated to the interpretation of various analyses on GEMPEHD before and after its use in the solar collector. The thermal aging GEMPEHD in the air is a physical loss and chemical consumption immediately followed by a brutal oxidation of the polymer. The losses would be governed primarily by the chemical consumption of antioxidants. After various tests, we conclude that the value of using the GEMPEHD as absorber in the solar collector is doubly beneficial. First, given its very attractive cost compared to other as efficient absorbers (such as metals gives good thermal performance of the solar collector even reaching 72%. While the life of the GEMPEHD is rather long (several years.

  14. Black germanium selective absorber surfaces. Final technical report, September 1, 1978-June 30, 1979

    Messier, R.; Vedam, K.; Krishnaswamy, S.V.

    1979-12-01

    Semiconductor films with an appropriate band gap (approx. 0.5 to 1.25 ev) have a high absorption coefficient in the solar spectrum region and high transmission in the IR thermal-emission region and thus make nearly ideal selective absorbers. However, due to their high refractive index, semiconductor films have high reflectance above their absorption edge which limits their total absorption. A coating which would retain the advantages of the semiconductor's selectivity and also reduce the reflectance from the present values of 30 to 50% to a level of less than 2% would be a significant advancement in the state of the art. This study describes work on the preparation and characterization of structurally anisotropic black Ge films by rf-sputtering and postdeposition etching. It has been shown that by controlling the sputtering preparation conditions of noncrystalline Ge films the surface microstructure can be drastically altered by simply etching in 30% H/sub 2/O/sub 2/. The total reflectance of the resulting surface was reduced from about 45% to less than 1%. Furthermore, the films appear black over a wide range of angles of incidence ( up to 45% from the normal). This flat black appearance is shown to be due to a dense array of aligned, needle-like protrusions which have an extremely high aspect ratio and both a cross-sectional area and a separation between the needles on th order of the wavelength of solar radiation. Black Ge films were obtained with a solar absorptance, ..cap alpha../sub S/, of greater than 0.99 in the best cases. Variation of ..cap alpha../sub S/ and epsilon/sub IR/ (IR emittance) with the thickness of the film and other preparation conditions is described. Further, the various microstructures are classified and understood on the basis of a structure zone model.

  15. Cost-Based Design and Selection of Point Absorber Devices for the Mediterranean Sea

    Vincenzo Piscopo

    2018-04-01

    Full Text Available Sea wave energy is one of the most promising renewable sources, even if relevant technology is not mature enough for the global energy market and is not yet competitive if compared with solar, wind and tidal current devices. Particularly, among the variety of wave energy converters developed in the last decade, heaving point absorbers represent one of the most feasible and studied technologies, as shown by the small-scale testing and full-scale prototypes, deployed in the last years throughout the world. Nevertheless, the need for further reduction of the energy production costs requires a specialized design of wave energy converters, accounting for the restraints provided by the power take-off unit and the device operational profile. Hence, actual analysis focuses on a new cost-based design procedure for heaving point absorbers. The device is equipped with a floating buoy with an optional fully submerged mass connected, by means of a tensioned line, to the power take-off unit. It consists of a permanent magnet linear generator, lying on the seabed and equipped with a gravity-based foundation. The proposed procedure is applied to several candidate deployment sites located in the Mediterranean Sea; the incidence of the power take-off restraint and the converter operational profile is fully investigated and some recommendations for preliminary design of wave energy converter devices are provided. Current results show that there is wide scope to make the wave energy sector more competitive on the international market, by properly selecting the main design parameters of point absorbers, on the basis of met-ocean conditions at the deployment site.

  16. Compositionally Graded Absorber for Efficient and Stable Near-Infrared-Transparent Perovskite Solar Cells.

    Fu, Fan; Pisoni, Stefano; Weiss, Thomas P; Feurer, Thomas; Wäckerlin, Aneliia; Fuchs, Peter; Nishiwaki, Shiro; Zortea, Lukas; Tiwari, Ayodhya N; Buecheler, Stephan

    2018-03-01

    Compositional grading has been widely exploited in highly efficient Cu(In,Ga)Se 2 , CdTe, GaAs, quantum dot solar cells, and this strategy has the potential to improve the performance of emerging perovskite solar cells. However, realizing and maintaining compositionally graded perovskite absorber from solution processing is challenging. Moreover, the operational stability of graded perovskite solar cells under long-term heat/light soaking has not been demonstrated. In this study, a facile partial ion-exchange approach is reported to achieve compositionally graded perovskite absorber layers. Incorporating compositional grading improves charge collection and suppresses interface recombination, enabling to fabricate near-infrared-transparent perovskite solar cells with power conversion efficiency of 16.8% in substrate configuration, and demonstrate 22.7% tandem efficiency with 3.3% absolute gain when mechanically stacked on a Cu(In,Ga)Se 2 bottom cell. Non-encapsulated graded perovskite device retains over 93% of its initial efficiency after 1000 h operation at maximum power point at 60 °C under equivalent 1 sun illumination. The results open an avenue in exploring partial ion-exchange to design graded perovskite solar cells with improved efficiency and stability.

  17. Compositionally Graded Absorber for Efficient and Stable Near‐Infrared‐Transparent Perovskite Solar Cells

    Pisoni, Stefano; Weiss, Thomas P.; Feurer, Thomas; Wäckerlin, Aneliia; Fuchs, Peter; Nishiwaki, Shiro; Zortea, Lukas; Tiwari, Ayodhya N.

    2018-01-01

    Abstract Compositional grading has been widely exploited in highly efficient Cu(In,Ga)Se2, CdTe, GaAs, quantum dot solar cells, and this strategy has the potential to improve the performance of emerging perovskite solar cells. However, realizing and maintaining compositionally graded perovskite absorber from solution processing is challenging. Moreover, the operational stability of graded perovskite solar cells under long‐term heat/light soaking has not been demonstrated. In this study, a facile partial ion‐exchange approach is reported to achieve compositionally graded perovskite absorber layers. Incorporating compositional grading improves charge collection and suppresses interface recombination, enabling to fabricate near‐infrared‐transparent perovskite solar cells with power conversion efficiency of 16.8% in substrate configuration, and demonstrate 22.7% tandem efficiency with 3.3% absolute gain when mechanically stacked on a Cu(In,Ga)Se2 bottom cell. Non‐encapsulated graded perovskite device retains over 93% of its initial efficiency after 1000 h operation at maximum power point at 60 °C under equivalent 1 sun illumination. The results open an avenue in exploring partial ion‐exchange to design graded perovskite solar cells with improved efficiency and stability. PMID:29593970

  18. Dynamic tuning of optical absorbers for accelerated solar-thermal energy storage.

    Wang, Zhongyong; Tong, Zhen; Ye, Qinxian; Hu, Hang; Nie, Xiao; Yan, Chen; Shang, Wen; Song, Chengyi; Wu, Jianbo; Wang, Jun; Bao, Hua; Tao, Peng; Deng, Tao

    2017-11-14

    Currently, solar-thermal energy storage within phase-change materials relies on adding high thermal-conductivity fillers to improve the thermal-diffusion-based charging rate, which often leads to limited enhancement of charging speed and sacrificed energy storage capacity. Here we report the exploration of a magnetically enhanced photon-transport-based charging approach, which enables the dynamic tuning of the distribution of optical absorbers dispersed within phase-change materials, to simultaneously achieve fast charging rates, large phase-change enthalpy, and high solar-thermal energy conversion efficiency. Compared with conventional thermal charging, the optical charging strategy improves the charging rate by more than 270% and triples the amount of overall stored thermal energy. This superior performance results from the distinct step-by-step photon-transport charging mechanism and the increased latent heat storage through magnetic manipulation of the dynamic distribution of optical absorbers.

  19. High-efficiency solar cell with earth-abundant liquid-processed absorber

    Todorov, Teodor K; Reuter, Kathleen B; Mitzi, David B [IBM T. J. Watson Research Center, Yorktown Heights, NY (United States)

    2010-05-25

    A composite liquid deposition approach merging the concepts of solution and particle-based coating for multinary chalcogenide materials is demonstrated. Photovoltaic absorbers based on earth-abundant Cu-Zn-Sn-S-Se kesterites show exceptional phase purity and are incorporated into solar cells with power conversion efficiency above 9.6%, bringing the state of the art of kesterite photovoltaic materials to a level suitable for possible commercialization. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  20. Design, simulation and optimization of a solar dish collector with spiral-coil thermal absorber

    Pavlović Saša R.

    2016-01-01

    Full Text Available The efficient conversion of solar radiation into heat at high temperature levels requires the use of concentrating solar collectors. The goal of this paper is to present the optical and the thermal analysis of a parabolic dish concentrator with a spiral coil receiver. The parabolic dish reflector consists of 11 curvilinear trapezoidal reflective petals constructed by PMMA with silvered mirror layer and has a diameter of 3.8 m, while its focal distance is 2.26m. This collector is designed with commercial software SolidWorks and simulated, optically and thermally in its Flow Simulation Studio. The optical analysis proved that the ideal position of the absorber is at 2.1m from the reflector in order to maximize the optical efficiency and to create a relative uniform heat flux over the absorber. In thermal part of the analysis, the energetic efficiency was calculated approximately 65%, while the exergetic efficiency is varied from 4% to 15% according to the water inlet temperature. Moreover, other important parameters as the heat flux and temperature distribution over the absorber are presented. The pressure drop of the absorber coil is calculated at 0.07bar, an acceptable value.

  1. First principle analyses of direct bandgap solar cells with absorbing substrates versus mirrors

    Kirk, Alexander P. [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Kirk, Wiley P. [Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, Texas 76019 (United States)

    2013-11-07

    Direct bandgap InP, GaAs, CdTe, and Ga{sub 0.5}In{sub 0.5}P solar cells containing backside mirrors as well as parasitically absorbing substrates are analyzed for their limiting open circuit voltage and power conversion efficiency with comparison to record solar cells. From the principle of detailed balance, it is shown quantitatively that mirror solar cells have greater voltage and power conversion efficiency than their substrate counterparts. Next, the radiative recombination coefficient and maximum radiative lifetime of GaAs mirror and substrate solar cells are calculated and compared to the nonradiative Auger and Shockley-Read-Hall (SRH) lifetimes. Mirror solar cells have greater radiative lifetime than their substrate variants. Auger lifetime exceeds radiative lifetime for both substrate and mirror cells while SRH lifetime may be less or greater than radiative lifetime depending on trap concentration and capture cross section. Finally, the change in free energy of the photogenerated carriers is analyzed in a comparison between InP, GaAs, CdTe, and Ga{sub 0.5}In{sub 0.5}P mirror and substrate solar cells in order to characterize the relationship between solar photon quality and free energy management in solar cells with differing bandgaps. Wider bandgap visible threshold Ga{sub 0.5}In{sub 0.5}P solar cells make better use of the available change in free energy of the photogenerated charge carriers, even when normalized to the bandgap energy, than narrower bandgap near-IR threshold InP, GaAs, and CdTe solar cells.

  2. Titanium-based spectrally selective surfaces for solar thermal systems

    Wilson, A D; Holmes, J P

    1983-10-01

    A study of spectrally selective surfaces based on anodic oxide films on titanium is presented. These surfaces have low values of solar absorptance, 0.77, due to the nonideal optical properties of the anodic TiO2 for antireflection of titanium. A simple chemical etching process is described which gives a textured surface with dimensions similar to the wavelengths of solar radiation, leading to spectral selectivity. The performance of this dark-etched surface can be further improved by anodising, and optimum absorbers have been produced with alpha(s) 0.935 and hemispherical emittances (400 K) 0.23. The surface texturing effects a significant improvement in alpha(s) at oblique incidence.

  3. Degradation of unglazed rough graphite-aluminium solar absorber surfaces in simulated acid and neutral rain

    Konttinen, P.; Lund, P.D.; Salo, T.

    2005-01-01

    Degradation mechanisms of unglazed solar absorber surfaces based on aluminium substrate were studied. Rough graphite-aluminium surfaces were total-immersion subjected to aerated and de-aerated simulated neutral and acid rain. Test conditions were based on calculated absorber stagnation temperature and global rain acidity measurements. Changes in optical properties, elemental composition and sample mass were examined by spectrometry, energy dispersive X-ray spectrometry and thermogravimetry, respectively. The absorbers exhibited almost no degradation at pH value of 3.5. At pH 5.5 alumina on the surface hydrated significantly degrading the optical properties of the surfaces severely in most cases. Therefore these absorber surfaces can not be recommended to be used in non-glazed applications if they are exposed to rain with pH exceeding ∼ 3.5-4.5. The total-immersion test needs to be developed further as the test results exhibited poor temperature and time dependency thus preventing accurate service lifetime estimates. Still, these tests were useful in determining favourable and non-favourable operating conditions for the absorber surfaces based on aluminium substrate. (author)

  4. A Solar Volumetric Receiver: Influence of Absorbing Cells Configuration on Device Thermal Performance

    Yilbas, B. S.; Shuja, S. Z.

    2017-01-01

    Thermal performance of a solar volumetric receiver incorporating the different cell geometric configurations is investigated. Triangular, hexagonal, and rectangular absorbing cells are incorporated in the analysis. The fluid volume fraction, which is the ratio of the volume of the working fluid over the total volume of solar volumetric receiver, is introduced to assess the effect of cell size on the heat transfer rates in the receiver. In this case, reducing the fluid volume fraction corresponds to increasing cell size in the receiver. SiC is considered as the cell material, and air is used as the working fluid in the receiver. The Lambert's Beer law is incorporated to account for the solar absorption in the receiver. A finite element method is used to solve the governing equation of flow and heat transfer. It is found that the fluid volume fraction has significant effect on the flow field in the solar volumetric receiver, which also modifies thermal field in the working fluid. The triangular absorbing cell gives rise to improved effectiveness of the receiver and then follows the hexagonal and rectangular cells. The second law efficiency of the receiver remains high when hexagonal cells are used. This occurs for the fluid volume fraction ratio of 0.5.

  5. Sol–gel derived solar selective coatings on SS 321 substrates for solar thermal applications

    Subasri, R., E-mail: subasri@arci.res.in; Soma Raju, K.R.C.; Reddy, D.S.; Hebalkar, Neha Y.; Padmanabham, G.

    2016-01-01

    Sol–gel derived multilayered solar selective coatings were generated on AISI SS 321 substrates using Ag-TiO{sub 2} as the cermet layer, titania and silica as the dielectric layers with high and low refractive indices respectively. The phase compositions of the individual layers were independently confirmed using grazing angle incidence X-ray diffraction, which was corroborated by X-ray photoelectron spectroscopic analysis. Thickness of the layers was measured using variable angle spectroscopic ellipsometry. The solar absorbance was measured over the UV–Vis-NIR wavelength range. Thermal emissivity was determined using FTIR spectroscopic analysis. The durability of the coatings was ascertained using accelerated corrosion testing methods as well as by measuring the optical properties after thermal cycling experiments. The promising nature of hexavalent chrome-free, environmental friendly, multilayered solar selective coating was ascertained with respect to amenability to scale-up. - Highlights: • Sol–gel derived multilayered solar selective coatings developed on SS321 • Solar absorptance and thermal emittance at par with toxic chrome coating • Thermal stability and corrosion resistance of coatings studied • Coating performance found to be promising for large scale applications • Scale-up amenability investigated by coating generation on 1 m tubes.

  6. Sol–gel derived solar selective coatings on SS 321 substrates for solar thermal applications

    Subasri, R.; Soma Raju, K.R.C.; Reddy, D.S.; Hebalkar, Neha Y.; Padmanabham, G.

    2016-01-01

    Sol–gel derived multilayered solar selective coatings were generated on AISI SS 321 substrates using Ag-TiO_2 as the cermet layer, titania and silica as the dielectric layers with high and low refractive indices respectively. The phase compositions of the individual layers were independently confirmed using grazing angle incidence X-ray diffraction, which was corroborated by X-ray photoelectron spectroscopic analysis. Thickness of the layers was measured using variable angle spectroscopic ellipsometry. The solar absorbance was measured over the UV–Vis-NIR wavelength range. Thermal emissivity was determined using FTIR spectroscopic analysis. The durability of the coatings was ascertained using accelerated corrosion testing methods as well as by measuring the optical properties after thermal cycling experiments. The promising nature of hexavalent chrome-free, environmental friendly, multilayered solar selective coating was ascertained with respect to amenability to scale-up. - Highlights: • Sol–gel derived multilayered solar selective coatings developed on SS321 • Solar absorptance and thermal emittance at par with toxic chrome coating • Thermal stability and corrosion resistance of coatings studied • Coating performance found to be promising for large scale applications • Scale-up amenability investigated by coating generation on 1 m tubes

  7. Glory on Venus and selection among the unknown UV absorbers

    Petrova, Elena V.

    2018-05-01

    The comparison of the phase profiles of glories observed on the cloud top of Venus by the Venus Monitoring Camera (Venus Express) and the light-scattering characteristics of sulfuric acid droplets, containing admixtures with a high refractive index, makes it easier to choose between some candidates for the so-called unknown UV absorber in the Venus clouds. Since among the candidates there are materials wetted and not wetted by sulfuric acid, we analyze whether small submicron particles adhered to or embedded into the 1-μm H2SO4 droplets may actually change the glory pattern normally produced by homogeneous spherical particles and what the conditions are, under which the composite particles formed in heterogeneous nucleation may still produce a glory feature. We have found that one of the most frequently considered candidates, sulfur, can hardly be responsible for the contrasts observed at 0.365 μm on the upper clouds, since it is not wetted by sulfuric acid and submicron sulfur particles, serving as condensation nuclei for sulfuric acid, can only adhere to the H2SO4 droplets rather than be enveloped by them. Such droplets decorated by sulfur blobs substantially distort the glory feature characteristic of the scattering by spherical particles or even smooth it at all, while a glory pattern is practically always seen in the images of Venus taken at small phase angles. At the same time, the grains of the other UV absorbers that can be embedded in H2SO4 droplets, e.g., the widely discussed ferric chloride, pose no problem in terms of interpretation of the observations of glory.

  8. Optimized reflectors for non-tracking solar collectors with tubular absorbers

    Muschaweck, Julius [Optics and Energy Consulting, Munich (Germany); Spirkl, Wolfgang [Ludwig-Maximilians Univ., Sektion Physik, Munich (Germany); Timinger, Andreas [Optics and Energy Consulting, Munich (Germany); ZAE Bayern, Solar Thermal and Biomass Dept., Munich (Germany); Benz, Nikolaus; Doerfler, Michael; Gut, Martin [ZAE Bayern, Solar Thermal and Biomass Dept., Munich (Germany); Kose, Erwin [microtherm Energietecjnik GmbH, Lods, 25 (France)

    2000-07-01

    We present an approach to find optimal reflector shapes for non-tracking solar collectors under practical constraints. We focus on cylindrical absorbers and reflectors with translational symmetry. Under idealised circumstances, edge ray reflectors are well known to be optimal. However, it is not clear how optimal reflectors should be shaped in order to obtain maximum utilisable energy for given operating temperatures under practical constraints like reflectivity less than unity, real radiation data, size limits, and gaps between the reflector and the absorber. For a prototype collector with a symmetric edge ray reflector and a tubular absorber, we derive from calorimetric measurements under outdoor conditions the optical efficiency as a function of the incidence angle. Using numerical optimisation and raytracing, we compare truncated symmetric edge ray reflectors, truncated asymmetric edge ray reflectors and free forms parametrized by Bezier splines. We find that asymmetric edge ray reflectors are optimal. For reasonable operating conditions, truncated asymmetric edge ray reflectors allow much better land use and easily adapt to a large range of roof tilt angles with marginal changes in collector construction. Except near the equator, they should increase the yearly utilisable energy per absorber tube by several percent as compared to the prototype collector with symmetric reflectors. (Author)

  9. Solar-absorbing metamaterial microencapsulation of phase change materials for thermo-regulating textiles

    William Tong

    2015-04-01

    Full Text Available This paper presents a novel concept for designing solar-absorbing metamaterial microcapsules of phase change materials (PCMs integrated with thermo-regulating smart textiles intended for coats or garments, especially for wear in space or cold weather on earth. The metamaterial is a periodically nanostructured metal-dielectric-metal thin film and can acquire surface plasmons to trap or absorb solar energy at subwavelength scales. This kind of metamaterial microencapsulation is not only able to take advantage of latent heat that can be stored or released from the PCMs over a tunable temperature range, but also has other advantages over conventional polymer microencapsulation of PCMs, such as enhanced thermal conductivity, improved flame-retardant capabilities, and usage as an extra solar power resource. The thermal analysis for this kind of microencapsulation has been done and can be used as a guideline for designing integrated thermo-regulating smart textiles in the future. These metamaterial microcapsules may open up new routes to enhancing thermo-regulating textiles with novel properties and added value.

  10. Black Cr/α-Cr2O3 nanoparticles based solar absorbers

    Khamlich, S.; Nemraoui, O.; Mongwaketsi, N.; McCrindle, R.; Cingo, N.; Maaza, M.

    2012-01-01

    Monodisperse spherical core–shell particles of Cr/α-Cr 2 O 3 with high adhesion were successfully coated on rough copper substrates by a simple self-assembly-like method for the use in solar thermal absorbers. The structure and morphology of the core-shell particles of Cr/α-Cr 2 O 3 were effectively controlled by deposition temperature and the pH of the initial precursor solution. Their characterizations were carried out with X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and attenuated total reflection, as well as UV–vis diffuse reflectance spectroscopy. The samples aged for more than 40 h at 75 °C exhibit the targeted high absorbing optical characteristic “Black chrome” while those aged for ≤40 h show a significant high UV–vis diffuse reflectance “green color”.

  11. Research on ration selection of mixed absorbent solution for membrane air-conditioning system

    Li, Xiu-Wei; Zhang, Xiao-Song; Wang, Fang; Zhao, Xiao; Zhang, Zhuo

    2015-01-01

    Highlights: • We derive models of the membrane air-conditioning system with mixed absorbents. • We make analysis on system COP, cost-effectiveness and economy. • The paper provides a new method for ideal absorbent selection. • The solutes concentration of 50% achieves the best cost-effectiveness and the economy. - Abstract: Absorption air-conditioning system is a good alternative to vapor compression system for developing low carbon society. To improve the performance of the traditional absorption system, the membrane air-conditioning system is configured and its COP can reach as high as 6. Mixed absorbents are potential for cost reduction of the membrane system while maintaining a high COP. On the purpose of finding ideal mixed absorbent groups, this paper makes analysis on COP, cost-effectiveness and economy of the membrane system with mixed LiBr–CaCl 2 absorbent solution. The models of the system have been developed for the analysis. The results show the COP is higher for the absorbent groups with lower concentration of the total solute and higher concentration ratio of LiBr. It also reveals when the total solutes concentration is about 50%, it achieves the best cost-effectiveness and the economy. The process of the analysis provides a useful method for mixed absorbents selection

  12. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

    Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

    2016-07-12

    A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

  13. Effect of p-layer properties on nanocrystalline absorber layer and thin film silicon solar cells

    Chowdhury, Amartya; Adhikary, Koel; Mukhopadhyay, Sumita; Ray, Swati

    2008-01-01

    The influence of the p-layer on the crystallinity of the absorber layer and nanocrystalline silicon thin film solar cells has been studied. Boron doped Si : H p-layers of different crystallinities have been prepared under different power pressure conditions using the plasma enhanced chemical vapour deposition method. The crystalline volume fraction of p-layers increases with the increase in deposition power. Optical absorption of the p-layer reduces as the crystalline volume fraction increases. Structural studies at the p/i interface have been done by Raman scattering studies. The crystalline volume fraction of the i-layer increases as that of the p-layer increases, the effect being more prominent near the p/i interface. Grain sizes of the absorber layer decrease from 9.2 to 7.2 nm and the density of crystallites increases as the crystalline volume fraction of the p-layer increases and its grain size decreases. With increasing crystalline volume fraction of the p-layer solar cell efficiency increases

  14. Methylammonium Bismuth Iodide as a Lead-Free, Stable Hybrid Organic-Inorganic Solar Absorber.

    Hoye, Robert L Z; Brandt, Riley E; Osherov, Anna; Stevanović, Vladan; Stranks, Samuel D; Wilson, Mark W B; Kim, Hyunho; Akey, Austin J; Perkins, John D; Kurchin, Rachel C; Poindexter, Jeremy R; Wang, Evelyn N; Bawendi, Moungi G; Bulović, Vladimir; Buonassisi, Tonio

    2016-02-18

    Methylammonium lead halide (MAPbX3 ) perovskites exhibit exceptional carrier transport properties. But their commercial deployment as solar absorbers is currently limited by their intrinsic instability in the presence of humidity and their lead content. Guided by our theoretical predictions, we explored the potential of methylammonium bismuth iodide (MBI) as a solar absorber through detailed materials characterization. We synthesized phase-pure MBI by solution and vapor processing. In contrast to MAPbX3, MBI is air stable, forming a surface layer that does not increase the recombination rate. We found that MBI luminesces at room temperature, with the vapor-processed films exhibiting superior photoluminescence (PL) decay times that are promising for photovoltaic applications. The thermodynamic, electronic, and structural features of MBI that are amenable to these properties are also present in other hybrid ternary bismuth halide compounds. Through MBI, we demonstrate a lead-free and stable alternative to MAPbX3 that has a similar electronic structure and nanosecond lifetimes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Flower garden trees' ability to absorb solar radiation heat for local heat reduction

    Maulana, Muhammad Ilham; Syuhada, Ahmad; Hamdani

    2017-06-01

    Banda Aceh as an urban area tends to have a high air temperature than its rural surroundings. A simple way to cool Banda Aceh city is by planting urban vegetation such as home gardens or parks. In addition to aesthetics, urban vegetation plays an important role as a reducer of air pollution, oxygen producer, and reducer of the heat of the environment. To create an ideal combination of plants, knowledge about the ability of plants to absorb solar radiation heat is necessary. In this study, some types of flowers commonly grown by communities around the house, such as Michelia Champaka, Saraca Asoka, Oliander, Adenium, Codiaeum Variegatum, Jas Minum Sambac, Pisonia Alba, Variegata, Apium Graveolens, Elephantopus Scaber, Randia, Cordylin.Sp, Hibiscus Rosasinensis, Agave, Lili, Amarilis, and Sesamum Indicum, were examined. The expected benefit of this research is to provide information for people, especially in Banda Aceh, on the ability of each plant relationship in absorbing heat for thermal comfort in residential environments. The flower plant which absorbs most of the sun's heat energy is Hibiscus Rosasinensis (kembang sepatu) 6.2 Joule, Elephantopus Scaber.L (tapak leman) 4.l Joule. On the other hand, the lowest heat absorption is Oliander (sakura) 0.9 Joule.

  16. Thin-Film Solar Cells with InP Absorber Layers Directly Grown on Nonepitaxial Metal Substrates

    Zheng, Maxwell

    2015-08-25

    The design and performance of solar cells based on InP grown by the nonepitaxial thin-film vapor-liquid-solid (TF-VLS) growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and indium tin oxide transparent top electrode. An ex situ p-doping process for TF-VLS grown InP is introduced. Properties of the cells such as optoelectronic uniformity and electrical behavior of grain boundaries are examined. The power conversion efficiency of first generation cells reaches 12.1% under simulated 1 sun illumination with open-circuit voltage (VOC) of 692 mV, short-circuit current (JSC) of 26.9 mA cm-2, and fill factor (FF) of 65%. The FF of the cell is limited by the series resistances in the device, including the top contact, which can be mitigated in the future through device optimization. The highest measured VOC under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP. The design and performance of solar cells based on indium phosphide (InP) grown by the nonepitaxial thin-film vapor-liquid-solid growth technique is investigated. The cell structure consists of a Mo back contact, p-InP absorber layer, n-TiO2 electron selective contact, and an indium tin oxide transparent top electrode. The highest measured open circuit voltage (VOC) under 1 sun is 692 mV, which approaches the optically implied VOC of ≈795 mV extracted from the luminescence yield of p-InP.

  17. Experimental investigation on a semi-circular trough-absorber solar still with baffles for fresh water production

    Sathyamurthy, Ravishankar; Nagarajan, P.K.; El-Agouz, S.A.; Jaiganesh, V.; Sathish Khanna, P.

    2015-01-01

    Highlights: • Experiments are carried out to analyze the performance. • Baffles are placed in the absorber to increase the residence time of water with solar intensity. • Yield of fresh water from present solar still is 16.66% more than a conventional solar still. • Payback period of the present model is quicker. - Abstract: The main objective of this research is to increase the contact time of water in the basin to enhance yield of fresh water by using a semicircular absorber solar still with baffles. An experimental as well as theoretical investigation is carried out. The productivity and efficiency of present still are analyzed with the influence of the number baffles and the water flow rate. A good agreement between the experimental and theoretical results is observed. The results indicate that, the daily yield of present solar still is higher than that for conventional still approximately by 16.66%. The outlet water temperature present solar still is high subsequently, it can be coupled with multi-state of solar stills to increase productivity. Therefore, the present solar still can be sufficiently extended for other continuous solar desalination systems. Economic analysis concluded that, the payback period of the present model solar still is quicker while comparing it with other solar still

  18. Energy and Exergy Analysis of Dual Channel Solar Air Collector with Different Absorber Plates Geometry

    Najim A. Jassim

    2018-04-01

    Full Text Available Flat-plate collector considers most common types of collectors, for ease of manufacturing and low price compared with other collectors. The main aim of the present work is to increase the efficiency of the collector, which can be achieved by improving the heat transfer and minimize heat loss experimentally. Five types of solar air collectors have been tested, which conventional channel with a smooth absorber plate (model I, dual channel with a smooth absorber plate (model II, dual channel with perforating “V” corrugated absorber plate (model III, dual channel with internal attached wire mesh (model Ⅳ, and dual channel with absorber sheet of transparent honeycomb, (model Ⅴ. The dual channel collector used for increasing heat transfer area and heat removal factor to improve thermal performance. The outdoor test was conducted during the period December (2016 to February (2017 at different mass flow rates 0.0217 kg/s, 0.0271 kg/s and 0.0325 kg/s. The experiments were carried out from 8:30 AM to 3:00 PM for clear days. Experimental results show that the average thermal efficiency was (72.2 % for model (III, (40.2 % for model (I, (51.6 % for model (II, (65.1 % for model (Ⅳ and (59.7 % for model (Ⅴ. At the last part of the study, the exergy analyses were derived for both collectors. The results of this part showed that the conventional channel model (I is having largest irreversibility, and the dual channel collector model (III is having a greatest exergetic efficiency.

  19. Characterization of rich in calcium materials using X-ray selective absorbers

    Guereca, G.; Ruvalcaba, J.L.

    2004-01-01

    For Particle Induced X-ray Emission Spectroscopy (PIXE) and X-ray Fluorescence Technique (FRX), the analysis of materials rich in one or two elements may present some difficulties due to high counting rates and saturation effects in X-ray detectors. In this case, it is possible to use selective absorbers in order to reduce the intensity of the major elements with low attenuation for the X-rays of other elements of the material. Using selective absorbers, the detection limits and the sensitivity are increased. For rich Ca materials (shells, bone, teeth and stucco, for instance), the high intensity of Ca X-rays interferes with the detection of lighter and heavier elements. Cl, Ar and Ag compounds are good candidates for Ca selective absorbers, but only Ag and Ar may have a practical absorber thickness. A selective absorber for Ca X-rays using a combination of thin Ag films and a flux of Ar and He was tested at the external beam setup of the Tandem Pelletron Accelerator for PIXE measurements. The improvement on elements detection on bone and colored stucco is shown. (Author) 8 refs., 2 tabs., 8 figs

  20. Organic solar cells with graded absorber layers processed from nanoparticle dispersions.

    Gärtner, Stefan; Reich, Stefan; Bruns, Michael; Czolk, Jens; Colsmann, Alexander

    2016-03-28

    The fabrication of organic solar cells with advanced multi-layer architectures from solution is often limited by the choice of solvents since most organic semiconductors dissolve in the same aromatic agents. In this work, we investigate multi-pass deposition of organic semiconductors from eco-friendly ethanol dispersion. Once applied, the nanoparticles are insoluble in the deposition agent, allowing for the application of further nanoparticulate layers and hence for building poly(3-hexylthiophene-2,5-diyl):indene-C60 bisadduct absorber layers with vertically graded polymer and conversely graded fullerene concentration. Upon thermal annealing, we observe some degrees of polymer/fullerene interdiffusion by means of X-ray photoelectron spectroscopy and Kelvin probe force microscopy. Replacing the common bulk-heterojunction by such a graded photo-active layer yields an enhanced fill factor of the solar cell due to an improved charge carrier extraction, and consequently an overall power conversion efficiency beyond 4%. Wet processing of such advanced device architectures paves the way for a versatile, eco-friendly and industrially feasible future fabrication of organic solar cells with advanced multi-layer architectures.

  1. Covering that selectively absorbs visible and infrared radiation, and method for the production thereof

    Céspedes, Eva; Prieto, C.; Escobar Galindo, R.; Sánchez-García, J. A.

    2011-01-01

    [EN] The present invention relates to a covering that selectively absorbs visible and infrared radiation, which comprises: (a) a first anti-diffusion barrier layer (2); (b) an IR-reflecting metallic layer (3) made from at least one metallic element selected from a group comprising Au, Ag, Al, Cu, Ti and Pt; (c) at least a second anti-diffusion barrier layer (4) formed by oxidation of the layer (3); (d) a structure that absorbs in the UV-VIS range, which comprises at least a first film (5) and...

  2. Interfacial Engineering and Charge Carrier Dynamics in Extremely Thin Absorber Solar Cells

    Edley, Michael

    Photovoltaic energy is a clean and renewable source of electricity; however, it faces resistance to widespread use due to cost. Nanostructuring decouples constraints related to light absorption and charge separation, potentially reducing cost by allowing a wider variety of processing techniques and materials to be used. However, the large interfacial areas also cause an increased dark current which negatively affects cell efficiency. This work focuses on extremely thin absorber (ETA) solar cells that used a ZnO nanowire array as a scaffold for an extremely thin CdSe absorber layer. Photoexcited electrons generated in the CdSe absorber are transferred to the ZnO layer, while photogenerated holes are transferred to the liquid electrolyte. The transfer of photoexcited carriers to their transport layer competes with bulk recombination in the absorber layer. After charge separation, transport of charge carriers to their respective contacts must occur faster than interfacial recombination for efficient collection. Charge separation and collection depend sensitively on the dimensions of the materials as well as their interfaces. We demonstrated that an optimal absorber thickness can balance light absorption and charge separation. By treating the ZnO/CdSe interface with a CdS buffer layer, we were able to improve the Voc and fill factor, increasing the ETA cell's efficiency from 0.53% to 1.34%, which is higher than that achievable using planar films of the same material. We have gained additional insight into designing ETA cells through the use of dynamic measurements. Ultrafast transient absorption spectroscopy revealed that characteristic times for electron injection from CdSe to ZnO are less than 1 ps. Electron injection is rapid compared to the 2 ns bulk lifetime in CdSe. Optoelectronic measurements such as transient photocurrent/photovoltage and electrochemical impedance spectroscopy were applied to study the processes of charge transport and interfacial recombination

  3. Growth and characterization of CdTe absorbers on GaAs by MBE for high concentration PV solar cells

    Ari, Ozan; Polat, Mustafa; Selamet, Yusuf [Department of Physics, Izmir Institute of Technology, Izmir 35430 (Turkey); Karakaya, Merve [Department of Material Science and Engineering, Izmir Institute of Technology, Izmir 35430 (Turkey)

    2015-11-15

    CdTe based II-VI absorbers are promising candidates for high concentration PV solar cells with an ideal band gap for AM1.5 solar radiation. In this study, we propose single crystal CdTe absorbers grown on GaAs substrates with a molecular beam epitaxy (MBE) which is a clean deposition technology. We show that high quality CdTe absorber layers can be grown with full width half maximum of X-ray diffraction rocking curves (XRD RC) as low as 227 arc-seconds with 0.5% thickness uniformity that a 2 μm layer is capable of absorbing 99% of AM1.5 solar radiation. Bandgap of the CdTe absorber is found as 1.483 eV from spetroscopic ellipsometry (SE) measurements. Also, high absorption coefficient is calculated from the results, which is ∝5 x 10{sup 5}cm{sup -1} in solar radiation spectrum. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    Patara, Lavinia [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel (Germany); Vichi, Marcello; Masina, Simona [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia (INGV), Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Fogli, Pier Giuseppe [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Manzini, Elisa [Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna (Italy); Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    2012-10-15

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall {approx}0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  5. Global response to solar radiation absorbed by phytoplankton in a coupled climate model

    Patara, Lavinia; Vichi, Marcello; Masina, Simona; Fogli, Pier Giuseppe; Manzini, Elisa

    2012-01-01

    The global climate response to solar radiation absorbed by phytoplankton is investigated by performing multi-century simulations with a coupled ocean-atmosphere-biogeochemistry model. The absorption of solar radiation by phytoplankton increases radiative heating in the near-surface ocean and raises sea surface temperature (SST) by overall ∼0.5 C. The resulting increase in evaporation enhances specific atmospheric humidity by 2-5%, thereby increasing the Earth's greenhouse effect and the atmospheric temperatures. The Hadley Cell exhibits a weakening and poleward expansion, therefore reducing cloudiness at subtropical-middle latitudes and increasing it at tropical latitudes except near the Equator. Higher SST at polar latitudes reduces sea ice cover and albedo, thereby increasing the high-latitude ocean absorption of solar radiation. Changes in the atmospheric baroclinicity cause a poleward intensification of mid-latitude westerly winds in both hemispheres. As a result, the North Atlantic Ocean meridional overturning circulation extends more northward, and the equatorward Ekman transport is enhanced in the Southern Ocean. The combination of local and dynamical processes decreases upper-ocean heat content in the Tropics and in the subpolar Southern Ocean, and increases it at middle latitudes. This study highlights the relevance of coupled ocean-atmosphere processes in the global climate response to phytoplankton solar absorption. Given that simulated impacts of phytoplankton on physical climate are within the range of natural climate variability, this study suggests the importance of phytoplankton as an internal constituent of the Earth's climate and its potential role in participating in its long-term climate adjustments. (orig.)

  6. Performance study of solar air heater duct having absorber plate with V down perforated baffles

    Sunil Chamoli

    2014-04-01

    Full Text Available This paper presents results of a study of the performance of solar air heaters with V down perforated baffles as roughness on the air flow side of the absorber plate. Investigations have been carried out using a mathematical model to study the effects of ambient conditions, operating and design parameters on effective efficiency of such air heaters. The thermal and effective efficiencies differ only marginally at lower flow rates. With an increase in the flow rate, the difference between the thermal and effective efficiencies increases because of the increase in the pumping power. The results of the study are presented in the form of plots to show the effect of ambient, design and operating conditions on thermal and effective efficiency.

  7. Study of thermal effects and optical properties of an innovative absorber in integrated collector storage solar water heater

    Taheri, Yaser; Alimardani, Kazem; Ziapour, Behrooz M.

    2015-10-01

    Solar passive water heaters are potential candidates for enhanced heat transfer. Solar water heaters with an integrated water tank and with the low temperature energy resource are used as the simplest and cheapest recipient devices of the solar energy for heating and supplying hot water in the buildings. The solar thermal performances of one primitive absorber were determined by using both the experimental and the simulation model of it. All materials applied for absorber such as the cover glass, the black colored sands and the V shaped galvanized plate were submerged into the water. The water storage tank was manufactured from galvanized sheet of 0.0015 m in thickness and the effective area of the collector was 0.67 m2. The absorber was installed on a compact solar water heater. The constructed flat-plate collectors were tested outdoors. However the simulation results showed that the absorbers operated near to the gray materials and all experimental results showed that the thermal efficiencies of the collector are over than 70 %.

  8. Production of crystalline refractory metal oxides containing colloidal metal precipitates and useful as solar-effective absorbers

    Narayan, Jagdish; Chen, Yok

    1983-01-01

    This invention is a new process for producing refractory crystalline oxides having improved or unusual properties. The process comprises the steps of forming a doped-metal crystal of the oxide; exposing the doped crystal in a bomb to a reducing atmosphere at superatmospheric pressure and a temperature effecting precipitation of the dopant metal in the crystal lattice of the oxide but insufficient to effect net diffusion of the metal out of the lattice; and then cooling the crystal. Preferably, the cooling step is effected by quenching. The process forms colloidal precipitates of the metal in the oxide lattice. The process may be used, for example, to produce thermally stable black MgO crystalline bodies containing magnetic colloidal precipitates consisting of about 99% Ni. The Ni-containing bodies are solar-selective absorbers, having a room-temperature absorptivity of about 0.96 over virtually all of the solar-energy spectrum and exhibiting an absorption edge in the region of 2 .mu.m. The process parameters can be varied to control the average size of the precipitates. The process can produce a black MgO crystalline body containing colloidal Ni precipitates, some of which have the face-centered-cubic structure and others of which have the body-centered cubic structure. The products of the process are metal-precipitate-containing refractory crystalline oxides which have improved or unique optical, mechanical, magnetic, and/or electronic properties.

  9. Spectrally-engineered solar thermal photovoltaic devices

    Lenert, Andrej; Bierman, David; Chan, Walker; Celanovic, Ivan; Soljacic, Marin; Wang, Evelyn N.; Nam, Young Suk; McEnaney, Kenneth; Kraemer, Daniel; Chen, Gang

    2018-03-27

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

  10. Analysis of absorbed energy and efficiency of a solar flat plate collector

    Anderson Miguel Lenz

    2017-07-01

    Full Text Available The highest percentage in home electricity demands in Brazil lies with the water heating systems, where the electric shower has a great contribution in consumption. The use of solar thermal panels is an alternative to minimize the strain on the electrical system by heating water. Current study evaluates a water heating system built with materials commonly used in home constructions. The tested collector is a 1 m² flat plate. Experiments were conducted at the State University of Western Paraná (UNIOESTE, campus Cascavel, Paraná State, Brazil. Temperature data were collected by PT100 sensors and solar radiation was measured with a pyranometer, coupled to a CR-1000 datalogger, with readings and collection every 5 minutes for 1 year. Data collection and analysis showed that the system presented monthly efficiency ranging between 33.7 and 53.54%, and energy absorbed between 30.79 and 75.29 kWh m-².month. Results show the system is a good option for use in residential or rural water heating due to decrease in the electric bill.

  11. Design principles for morphologies of antireflection patterns for solar absorbing applications.

    Moon, Yoon-Jong; Na, Jin-Young; Kim, Sun-Kyung

    2015-07-01

    Two-dimensional surface texturing is a widespread technology for imparting broadband antireflection, yet its design rules are not completely understood. The dependence of the reflectance spectrum of a periodically patterned glass film on various structural parameters (e.g., pitch, height, shape, and fill factor) has been investigated by means of full-vectorial numerical simulations. An average weighted reflectivity accounting for the AM1.5G solar spectrum (λ=300-1000  nm) was sinusoidally modulated by a rod pattern's height, and was minimized for pitches of 400-600 nm. When a rationally optimized cone pattern was used, the average weighted reflectivity was less than 0.5%, for incident angles of up to 40° off normal. The broadband antireflection of a cone pattern was reproduced well by a graded refractive index film model corresponding to its geometry, with the addition of a diffraction effect resulting from its periodicity. The broadband antireflection ability of optimized cone patterns is not limited to the glass material, but rather is generically applicable to other semiconductor materials, including Si and GaAs. The design rules developed herein represent a key step in the development of light-absorbing devices, such as solar cells.

  12. Solar Photothermal Disinfection using Broadband-Light Absorbing Gold Nanoparticles and Carbon Black.

    Loeb, Stephanie; Li, Chuanhao; Kim, Jae-Hong

    2018-01-02

    A simple heat treatment, perhaps the most globally recognized point-of-use water sterilization method, is seemingly effective against all major pathogens of concern, but bulk water boiling is not energy efficient or sustainable. Herein, we present the first application of solar-to-thermal converting nanomaterials for the direct inactivation of bacteria and viruses in drinking water through the application of Au nanorods, carbon black, and Au nanorod-carbon black composite materials as light absorbers. With broad absorption bands spanning the visible and near-infrared wavelengths, at sufficient concentrations, these nanoparticles induce multiple scattering events, increasing photon absorption probability and concentrating the light within a small spatial domain, leading to localized, intense heating that inactivates microorganisms in close proximity. Moving toward practical device design, we have developed a facile silane immobilization approach to fabricate films with densely packed layers of photothermal nanomaterials. Our results suggest that upon irraditaion with simulated solar light, these films can thermally inactivate bacteria and viruses, as demonstrated through the inactivation of surrogate organisms Escherichia coli K-12, and bacteriophages MS2 and PR772.

  13. Influence of the local absorber layer thickness on the performance of ZnO nanorod solar cells

    Belaidi, Abdelhak; Dittrich, Thomas; Kieven, David; Tornow, Julian; Schwarzburg, Klaus; Lux-Steiner, Martha [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany)

    2008-08-15

    The local absorber layer thickness (d{sub local}) of solar cells with extremely thin absorber was changed between 10 nm and 70 nm. As a model system, ZnO nanorod arrays (electron conductor) with fixed internal surface area coated with In{sub 2}S{sub 3} (absorber) and impregnated with CuSCN (transparent hole conductor) were applied. The performance of the small area solar cells depended critically on d{sub local}. The highest short circuit current density was reached for the lowest d{sub local}. In contrast, the highest open circuit voltage was obtained for the highest d{sub local}. A maximum energy conversion efficiency of 3.4% at AM1.5 was achieved. Limiting factors are discussed.(copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Absorbed Doses to Embryo from Intravenous Urography at Selected Radiological Departments in Slovakia

    Karkus, R.; Nikodemova, D.; Horvathova, M.

    2003-01-01

    Actual legislation used in radiological protection requires quality assurance program for decreasing radiation load of patients from radiological examinations. The information about irradiation of pregnant women is very important, because the embryo is more radiosensitive as adult organism. On the basis of absence of unified calculations or measurements of absorbed doses to embryo from various radiological examinations in Slovakia we present in this study the values of absorbed doses to embryo from intravenous urography at selected radiological departments in Slovakia. Absorbed doses to embryo were obtained by measurement and calculation using the simulation of irradiation of pregnant woman by intravenous urography. The results of our study indicate, that absorbed doses to embryo were at various radiological departments considerably different, depending on type of X-ray machine and different settings of technical parameters of X-ray machine. In accordance with worldwide trend it is necessary to decrease radiation load of patients as low as possible level. Differences in radiation load between radiological departments indicate, that it is necessary to continue in solving of this problem and perform measurements and calculations of absorbed doses to embryo at different types of X-ray machines and at different examinations, where the embryo is in direct beam of X-ray. (author)

  15. Investigation of Non-Vacuum Deposition Techniques in Fabrication of Chalcogenide-Based Solar Cell Absorbers

    Alsaggaf, Ahmed

    2015-07-01

    The environmental challenges are increasing, and so is the need for renewable energy. For photovoltaic applications, thin film Cu(In,Ga)(S,Se)2 (CIGS) and CuIn(S,Se)2 (CIS) solar cells are attractive with conversion efficiencies of more than 20%. However, the high-efficiency cells are fabricated using vacuum technologies such as sputtering or thermal co-evaporation, which are very costly and unfeasible at industrial level. The fabrication involves the uses of highly toxic gases such as H2Se, adding complexity to the fabrication process. The work described here focused on non-vacuum deposition methods such as printing. Special attention has been given to printing designed in a moving Roll-to-Roll (R2R) fashion. The results show potential of such technology to replace the vacuum processes. Conversion efficiencies for such non-vacuum deposition of Cu(In,Ga)(S,Se)2 solar cells have exceeded 15% using hazardous chemicals such as hydrazine, which is unsuitable for industrial scale up. In an effort to simplify the process, non-toxic suspensions of Cu(In,Ga)S2 molecular-based precursors achieved efficiencies of ~7-15%. Attempts to further simplify the selenization step, deposition of CuIn(S,Se)2 particulate solutions without the Ga doping and non-toxic suspensions of Cu(In,Ga)Se2 quaternary precursors achieved efficiencies (~1-8%). The contribution of this research was to provide a new method to monitor printed structures through spectral-domain optical coherence tomography SD-OCT in a moving fashion simulating R2R process design at speeds up to 1.05 m/min. The research clarified morphological and compositional impacts of Nd:YAG laser heat-treatment on Cu(In,Ga)Se2 absorber layer to simplify the annealing step in non-vacuum environment compatible to R2R. Finally, the research further simplified development methods for CIGS solar cells based on suspensions of quaternary Cu(In,Ga)Se2 precursors and ternary CuInS2 precursors. The methods consisted of post deposition reactive

  16. Impacts of solar-absorbing aerosol layers on the transition of stratocumulus to trade cumulus clouds

    X. Zhou

    2017-10-01

    Full Text Available The effects of an initially overlying layer of solar-absorbing aerosol on the transition of stratocumulus to trade cumulus clouds are examined using large-eddy simulations. For lightly drizzling cloud the transition is generally hastened, resulting mainly from increased cloud droplet number concentration (Nc induced by entrained aerosol. The increased Nc slows sedimentation of cloud droplets and shortens their relaxation time for diffusional growth, both of which accelerate entrainment of overlying air and thereby stratocumulus breakup. However, the decrease in albedo from cloud breakup is more than offset by redistributing cloud water over a greater number of droplets, such that the diurnal-average shortwave forcing at the top of the atmosphere is negative. The negative radiative forcing is enhanced by sizable longwave contributions, which result from the greater cloud breakup and a reduced boundary layer height associated with aerosol heating. A perturbation of moisture instead of aerosol aloft leads to a greater liquid water path and a more gradual transition. Adding absorbing aerosol to that atmosphere results in substantial reductions in liquid water path (LWP and cloud cover that lead to positive shortwave and negative longwave forcings on average canceling each other. Only for heavily drizzling clouds is the breakup delayed, as inhibition of precipitation overcomes cloud water loss from enhanced entrainment. Considering these simulations as an imperfect proxy for biomass burning plumes influencing Namibian stratocumulus, we expect regional indirect plus semi-direct forcings to be substantially negative to negligible at the top of the atmosphere, with its magnitude sensitive to background and perturbation properties.

  17. Improving the Morphology of the Perovskite Absorber Layer in Hybrid Organic/Inorganic Halide Perovskite MAPbI3 Solar Cells

    I. J. Ogundana

    2017-01-01

    Full Text Available Recently, perovskite solar cells have attracted tremendous attention due to their excellent power conversion efficiency, low cost, simple fabrications, and high photovoltaic performance. Furthermore, the perovskite solar cells are lightweight and possess thin film and semitransparency. However, the nonuniformity in perovskite layer constitutes a major setback to the operation mechanism, performance, reproducibility, and degradation of perovskite solar cells. Therefore, one of the main challenges in planar perovskite devices is the fabrication of high quality films with controlled morphology and least amount of pin-holes for high performance thin film perovskite devices. The poor reproducibility in perovskite solar cells hinders the accurate fabrication of practical devices for use in real world applications, and this is primarily as a result of the inability to control the morphology of perovskites, leading to large variability in the characteristics of perovskite solar cells. Hence, the focus of research in perovskites has been mostly geared towards improving the morphology and crystallization of perovskite absorber by selecting the optimal annealing condition considering the effect of humidity. Here we report a controlled ambient condition that is necessary to grow uniform perovskite crystals. A best PCE of 7.5% was achieved along with a short-circuit current density of 15.2 mA/cm2, an open-circuit voltage of 0.81 V, and a fill factor of 0.612 from the perovskite solar cell prepared under 60% relative humidity.

  18. Influence of solvents on properties of solar selective coatings

    Solar selective coatings for solar thermal flat-plate collectors consisting of crystalline copper oxides and amorphous nickel oxide composites were obtained by robotic spray pyrolyzed deposition. The parameters were optimized for increased spectral selectivity (): high solar absorptance and low thermal emittance.

  19. Two new methods used to simulate the circumferential solar flux density concentrated on the absorber of a parabolic trough solar collector

    Guo, Minghuan; Wang, Zhifeng; Sun, Feihu

    2016-05-01

    The optical efficiencies of a solar trough concentrator are important to the whole thermal performance of the solar collector, and the outer surface of the tube absorber is a key interface of energy flux. So it is necessary to simulate and analyze the concentrated solar flux density distributions on the tube absorber of a parabolic trough solar collector for various sun beam incident angles, with main optical errors considered. Since the solar trough concentrators are linear focusing, it is much of interest to investigate the solar flux density distribution on the cross-section profile of the tube absorber, rather than the flux density distribution along the focal line direction. Although a few integral approaches based on the "solar cone" concept were developed to compute the concentrated flux density for some simple trough concentrator geometries, all those integral approaches needed special integration routines, meanwhile, the optical parameters and geometrical properties of collectors also couldn't be changed conveniently. Flexible Monte Carlo ray trace (MCRT) methods are widely used to simulate the more accurate concentrated flux density distribution for compound parabolic solar trough concentrators, while generally they are quite time consuming. In this paper, we first mainly introduce a new backward ray tracing (BRT) method combined with the lumped effective solar cone, to simulate the cross-section flux density on the region of interest of the tube absorber. For BRT, bundles of rays are launched at absorber-surface points of interest, directly go through the glass cover of the absorber, strike on the uniformly sampled mirror segment centers in the close-related surface region of the parabolic reflector, and then direct to the effective solar cone around the incident sun beam direction after the virtual backward reflection. All the optical errors are convoluted into the effective solar cone. The brightness distribution of the effective solar cone is supposed

  20. Seasonal Evolution and Interannual Variability of the Local Solar Energy Absorbed by the Arctic Sea Ice-Ocean System

    Perovich, Donald K.; Nghiem, Son V.; Markus, Thorsten; Schwieger, Axel

    2007-01-01

    The melt season of the Arctic sea ice cover is greatly affected by the partitioning of the incident solar radiation between reflection to the atmosphere and absorption in the ice and ocean. This partitioning exhibits a strong seasonal cycle and significant interannual variability. Data in the period 1998, 2000-2004 were analyzed in this study. Observations made during the 1997-1998 SHEBA (Surface HEat Budget of the Arctic Ocean) field experiment showed a strong seasonal dependence of the partitioning, dominated by a five-phase albedo evolution. QuikSCAT scatterometer data from the SHEBA region in 1999-2004 were used to further investigate solar partitioning in summer. The time series of scatterometer data were used to determine the onset of melt and the beginning of freezeup. This information was combined with SSM/I-derived ice concentration, TOVS-based estimates of incident solar irradiance, and SHEBA results to estimate the amount of solar energy absorbed in the ice-ocean system for these years. The average total solar energy absorbed in the ice-ocean system from April through September was 900 MJ m(sup -2). There was considerable interannual variability, with a range of 826 to 1044 MJ m(sup -2). The total amount of solar energy absorbed by the ice and ocean was strongly related to the date of melt onset, but only weakly related to the total duration of the melt season or the onset of freezeup. The timing of melt onset is significant because the incident solar energy is large and a change at this time propagates through the entire melt season, affecting the albedo every day throughout melt and freezeup.

  1. EXPERIMENTAL STUDY ON DOUBLE PASS SOLAR AIR HEATER WITH MESH LAYERS AS ABSORBER PLATE

    Raheleh Nowzaria

    2014-01-01

    Full Text Available The double pass solar air heater is constructed and tested for thermal efficiency at a geographic location of Cyprus in the city of Famagusta. The absorber plate was replaced by fourteen steel wire mesh layers, 0.2 × 0.2 cm in cross section opening, and they were fixed in the duct parallel to the glazing. The distance between each set of wire mesh layers is 0.5cm to reduce the pressure drop. The wire mesh layers were painted with black before installing them into the collector. The obtained results show that as the mass flow rate increases, the efficiency of the system also increases. The temperature difference (ΔT between the inlet and outlet air through the system increases as the mass flow rate decreases. The maximum ΔT (53°C is achieved at the flow rate of 0.011 kg/s. The range of the mass flow rate used in this work is between 0.011 and 0.037 kg/s. It is also found that the average efficiency obtained for the double pass air collector is 53.7% for the mass flow rate of 0.037 kg/s.

  2. Theoretical study of quaternary compounds as thin-film solar cell absorber

    Su, Huai Wei

    2010-01-01

    Full text : Design of chalcogenide photovoltaic absorbers is carried out systematically through sequential cation mutation, from binary to ternary to quaternary compounds, using first-principles electronic structure calculations. Several universal trends are found for the ternary and two classes of quaternary chalcogenides. For example, the lowest-energy structure always has larger lattice constant a, smaller tetragonal distortion parameter η=c/2a, and larger band gap than the metastable structures for common-row cation mutations. The band gap is reduced during the mutation. The band gap decreases from binary II-VI to ternary I-III-VI 2 are mostly due to the p-d repulsion in the valence band, the decreases from ternary I-III-VI 2 to quaternary I 2 -II-IV-VI 4 chalcogenides are due to the downshift in the conduction band caused by the wavefunction localization on the group IV cation site. It was found that I 2 -II-IV-VI 4 compounds are more stable in the kesterite structure, whereas the widely-assumed stannite structure reported in the literature is most likely due to partial disorder in the I-II layer of the kesterite phase. Among the derived quaternary compounds, Cu 2 ZnSnS 4 (CZTS) is one of the ideal candidate absorber materials for thin-film solar cells with an optimal band gap, high absorption coefficient, abundant elemental components, and is adaptable to various growth techniques. It was performed a series of first-principles electronic structure calculations for CZTS. Also it was found that in the ground state kesterite structure, (i) the chemical potential region that CZTS can form is very small. Therefore, it will be very difficult to obtain high quality stoichiometric CZTS samples; (ii) The dominant p-type acceptor in CZTS is CuZn, however, the associated acceptor level is relatively high, suggesting that p-type doping in CZTS is more difficult than ternary compounds such as CuInSe 2 ; (iii) The formation of the self-compensated defect pair [Cu

  3. A numerical model for pressure drop and flow distribution in a solar collector with U-connected absorber pipes

    Bava, Federico; Furbo, Simon

    2016-01-01

    This study presents a numerical model calculating the pressure drop and flow distribution in a solar collector with U-type harp configuration in isothermal conditions. The flow maldistribution in the absorber pipes, caused by the different hydraulic resistances, was considered to evaluate...... the pressure drop across the collector. The model was developed in Matlab and is based on correlations found in literature for both friction losses and local losses, and was compared in terms of overall pressure drop against experimental measurements carried out on an Arcon Sunmark HT 35/10 solar collector...

  4. Scanning tunneling spectroscopy on the chalcopyrite solar cell absorber material Cu(In,Ga)Se{sub 2}

    Moenig, Harry; Saez-Araoz, Rodrigo; Lux-Steiner, Martha [Freie Universitaet Berlin (Germany); Sadewasser, Sascha; Ennaoui, Ahmed; Kaufmann, Christian; Kropp, Timo; Lauermann, Iver; Muenchenberg, Tim; Schock, Hans-Werner; Streicher, Ferdinand [Hahn- Meitner-Institut Berlin (Germany)

    2007-07-01

    Cu(In,Ga)Se{sub 2}-based thin film solar cells have reached efficiencies close to 20%. Nevertheless, little is known about electronic transport and carrier recombination in this material on a microscopic scale. Especially grain boundaries in these polycrystalline materials are considered to play an important role in the performance of these solar cells. We applied scanning tunneling microscopy and spectroscopy to gain more insight in the electronic microstructure of the material. Our results point to lateral electronic inhomogeneities on the absorber surface and to an enhanced density of states at grain boundaries. The influence of charging effects is discussed.

  5. Three-dimensional reciprocal space profile of an individual nanocrystallite inside a thin-film solar cell absorber layer

    Slobodskyy, Taras; Schroth, Philip; Minkevich, Andrey; Grigoriev, Daniil; Fohtung, Edwin; Riotte, Markus; Baumbach, Tilo; Powalla, Michael; Lemmer, Uli; Slobodskyy, Anatoliy

    2013-01-01

    The strain profile of an individual Cu(In,Ga)Se 2 nanocrystallite in a solar cell absorber layer is accessed using synchrotron radiation. We find that the investigated crystallite is inhomogeneously strained. The strain is most likely produced by a combination of intergranular strain and composition variations in nanocrystals inside the polycrystalline semiconductor film and carries information about the intercrystalline interaction. The measurements are made nondestructively and without additional sample preparation or x-ray beam nanofocusing. This is the first step towards measurements of strain profiles of individual crystallites inside a working solar cell. (paper)

  6. A numerical model for pressure drop and flow distribution in a solar collector with U-connected absorber pipes

    Bava, Federico; Furbo, Simon

    2016-01-01

    increased, but remained within the accuracy of the differential pressure sensor. The flow distribution was mainly affected by the flow regime in the manifolds. Turbulent regime throughout the manifolds entailed a more uniform distribution across the absorber pipes compared to laminar regime. The comparison......This study presents a numerical model calculating the pressure drop and flow distribution in a solar collector with U-type harp configuration in isothermal conditions. The flow maldistribution in the absorber pipes, caused by the different hydraulic resistances, was considered to evaluate...... the pressure drop across the collector. The model was developed in Matlab and is based on correlations found in literature for both friction losses and local losses, and was compared in terms of overall pressure drop against experimental measurements carried out on an Arcon Sunmark HT 35/10 solar collector...

  7. Year-round performance of a modified single-basin solar still with mica plate as a suspended absorber

    El-Sebaii, A.A.; Aboul-Enein, S.; Ramadan, M.R.I.; El-Bialy, E. [Tanta University (Egypt). Faculty of Science

    2000-01-01

    In a previous study, a single-basin solar still with suspended absorber (SBSSBA) made from aluminium was constructed and investigated experimentally and theoretically. It was found that the daily productivity of the still was about 20% higher than that of the conventional single-basin solar still (SBSS). In this paper, the effect of thermal conductivity of the suspended absorber on the daily productivity of the still is investigated experimentally using aluminium, copper, stainless steel and mica plates as suspended absorbers. The results obtained are compared with those obtained for the SBSS tested under the same climatic conditions of Tanta (lat. 30{sup o} 47' N). The results indicate that it is advisable to use suspended plates made from insulating materials, such as mica, plastic, glass, etc. The daily productivity of the modified still with mica is found to be 42% higher than that of SBSS. Further, the effect of thickness of the suspended absorber on the productivity as well as the year-round performances of both SBSSBA and SBSS for the year 1996 are studied by computer simulation. There is good evidence that the productivity of SBSSBA is less dependent on the thickness of the suspended plate. The annual average productivities of the modified still with mica are found to be 23 and 15.8% higher than those of the conventional still when the basin water masses are 80 and 40 kg, respectively. This indicates that the suspended plate becomes more effective at higher masses of basin water. (author)

  8. Performance Study of Photovoltaic-Thermal (Pv/T) Solar Collector with ·-Grooved Absorber Plate

    Mohd Yusof Othman; Hafidz Ruslan; Kamaruzzaman Sopian; Jin, G.L.

    2009-01-01

    A hybrid photovoltaic-thermal solar collector has been designed, built and its performance has been studied. The advantage of the collector is that it can generate electricity and heat simultaneously. Photovoltaic module SHARP NE-80E2EA with maximum output power of 80 W was used to generate electricity. The module also acts as heat absorber of the collector. Single pass ·-groove collector made of aluminium sheet with 0.7 mm thickness has been used to collect heat generated. Study was conducted under a designed halogen lamps solar simulator with intensities set at 386 ± 8 Wm -2 and 817 ± 8 Wm -2 . The speed of air passing through the collector was set between (69.6 ± 2.2) x 10 -4 kg/s to (695.8 ± 2.2) x 10 -4 kg/s. The objective of the study is to compare the performance of PV/T collector with and without ·-groove absorber. The study found that the PV/T collector with ·-groove absorber plate has higher efficiency than the PV/T without ·-groove absorber. The electrical and thermal efficiencies are also increased when radiation intensity and speed of air increase. (author)

  9. Experimental study on depth of paraffin wax over floating absorber plate in built-in storage solar water heater

    R Sivakumar

    2015-11-01

    Full Text Available The aim of this article is to study the effect of depth of phase change material over the absorber surface of an integrated collector-storage type flat plate solar water heater. Flat plate solar water heaters are extensively used all over the world to utilize the natural source of solar energy. In order to utilize the solar energy during off-sunshine hours, it is inevitable to store and retain solar thermal energy as long as possible. Here, phase change material is not used for heat storage, but to minimize losses during day and night time only. The depth of phase change material over a fixed depth of water in a solar thermal collector is an important geometric parameter that influences the maximum temperature rise during peak solar irradiation and hence the losses. From the results of the studies for different masses of paraffin wax phase change material layers, the optimum depth corresponding to the maximum heat gain till evening is found to be 2 mm, and the heat retention till the next day morning is found to be 4 mm.

  10. Reduction of secondary phases in Cu{sub 2}SnSe{sub 3} absorbers for solar cell application

    Tang, Zeguo, E-mail: tangzg@fc.ritsumei.ac.jp [Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Shiga (Japan); Nukui, Yuki; Kosaka, Kiichi; Ashida, Naoki; Uegaki, Hikaru; Minemoto, Takashi [College of Science and Engineering, Ritsumeikan University, Shiga (Japan)

    2014-09-01

    Highlights: • Cu{sub 2}SnSe{sub 3} thin films for absorber of solar cell are fabricated by selenization of Cu–Sn precursors. • Secondary phase of Cu{sub 2–x}Se can be suppressed via using Se and SnSe mixture powders as Se source. • Selective etching of secondary phase of Cu{sub 2–x}Se is realized by potassium cyanide solution. • Cu{sub 2–x}Se rather than SnSe makes major contribution to the high carrier concentration of CTSe films. - Abstract: The creation of secondary phases, such as Cu{sub 2−x}Se and SnSe, and their influence on electrical properties of Cu{sub 2}SnSe{sub 3} (CTSe) thin films fabricated by selenization of Cu–Sn metal precursors are investigated. The Cu{sub 2−x}Se content in CTSe films is estimated via deconvolution of grazing incidence X-ray diffraction (GIXRD) patterns, and the results suggest that the Cu{sub 2−x}Se content increases with the increasing Cu/Sn ratio in metal precursors. We also found that using Se and SnSe mixture powders as Se source is an effective approach to suppress the creation of Cu{sub 2−x}Se secondary phase. Meanwhile, selective etching of Cu{sub 2−x}Se is realized by potassium cyanide (KCN) solution. Hall measurement results reveal that the secondary phase of Cu{sub 2−x}Se rather than SnSe makes major contribution to the high carrier concentration (larger than 10{sup 18} cm{sup −3}) of CTSe films. The approach to further decrease the carrier concentration in CTSe films is discussed.

  11. Development of Solar Drying Model for Selected Cambodian Fish Species

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h...

  12. Heat transfer characteristics in the channel of a finned absorber solar collector; Caracteristicas da transferencia de calor no canal de um coletor solar de absorvedor aletado

    Saboya, Sergio Mourao [Centro Tecnico Aeroespacial, Sao Jose dos Campos, SP (Brazil). Inst. Tecnologico de Aeronautica; Saboya, Francisco Eduardo Mourao [Universidade Federal Fluminense, Niteroi, RJ (Brazil)]. E-mails: saboya@mec.ita.cta.br; fsaboya@mec.uff.br

    2000-07-01

    Finned absorber solar collectors are devices in which plates (fins) are fixed perpendicularly to the absorber plate. The purpose of these fins is to cause the so called 'cavity effect', lowering the collector losses. This paper studies the heat transfer that occurs in the collector channel. This analysis is done using the efficiency of the collector, which is calculated solving the system of equations that govern the collector thermal behavior, and the computation of the convection heat transfer between the fluid flowing in the channel and the absorber plate. This analysis allows the calculation of design parameters such as mass flow rate and exit bulk temperature of the fluid. (author)

  13. Super-hydrophilic copper sulfide films as light absorbers for efficient solar steam generation under one sun illumination

    Guo, Zhenzhen; Ming, Xin; Wang, Gang; Hou, Baofei; Liu, Xinghang; Mei, Tao; Li, Jinhua; Wang, Jianying; Wang, Xianbao

    2018-02-01

    Solar steam technology is one of the simplest, most direct and effective ways to harness solar energy through water evaporation. Here, we report the development using super-hydrophilic copper sulfide (CuS) films with double-layer structures as light absorbers for solar steam generation. In the double-layer structure system, a porous mixed cellulose ester (MCE) membrane is used as a supporting layer, which enables water to get into the CuS light absorbers through a capillary action to provide continuous water during solar steam generation. The super-hydrophilic property of the double-layer system (CuS/MCE) leads to a thinner water film close to the air-water interface where the surface temperature is sufficiently high, leading to more efficient evaporation (˜80 ± 2.5%) under one sun illumination. Furthermore, the evaporation efficiencies still keep a steady value after 15 cycles of testing. The super-hydrophilic CuS film is promising for practical application in water purification and evaporation as a light absorption material.

  14. Thermo-hydraulic performance of solar air heater having multiple v-shaped rib roughness on absorber plates

    Dhananjay Kumar

    2018-03-01

    Full Text Available This paper presents the performance analysis of the effect of geometrical parameters having multiple v-shaped rib roughness on the airflow side of the absorber plates. Mathematical approach and solution procedure for the analysis of such a solar air heater has been developed theoretically and MATLAB code generated for the solution of the mathematical equations. The effect of parameters such as flow Reynolds number and Relative roughness height on the thermohydraulic performance have been examined and compared with the conventional flat plate solar air heater. A substantial improvement in thermal efficiency of roughened solar air heater as compared to smooth one due to appreciable enhancement in heat transfer coefficient. The enhancement in heat transfer coefficient is also accompanied by a considerable enhancement in pumping power requirement due to the increase in friction factor.

  15. Nanoimprinted backside reflectors for a-Si:H thin-film solar cells: critical role of absorber front textures.

    Tsao, Yao-Chung; Fisker, Christian; Pedersen, Thomas Garm

    2014-05-05

    The development of optimal backside reflectors (BSRs) is crucial for future low cost and high efficiency silicon (Si) thin-film solar cells. In this work, nanostructured polymer substrates with aluminum coatings intended as BSRs were produced by positive and negative nanoimprint lithography (NIL) techniques, and hydrogenated amorphous silicon (a-Si:H) was deposited hereon as absorbing layers. The relationship between optical properties and geometry of front textures was studied by combining experimental reflectance spectra and theoretical simulations. It was found that a significant height variation on front textures plays a critical role for light-trapping enhancement in solar cell applications. As a part of sample preparation, a transfer NIL process was developed to overcome the problem of low heat deflection temperature of polymer substrates during solar cell fabrication.

  16. Parabolic solar concentrators with fully illuminated inverted V absorber; Coletor concentrador parabolico composto (CPC) com absorvedor V invertido completamente iluminado

    Brandao, Braulio Bezerra

    2004-10-01

    Although literature on parabolic solar concentrators is numerically considerable, there are no publications regarding CPC with fully illuminate, inverted V absorber, nothing is mentioned about optical and geometric properties or, collected thermal energy. This type of solar concentrator exists in the international market, but with little known divulgence of its properties, perhaps explained because of industrial protection. In the first part of this work, the equations that define the concentrator cavity curve and its optical and geometric properties were deduced and studied in detail, by a numeric simulation program, elaborated in Meatball language. Additionally, optimization studies about the viability of the construction of this collector were carried out, relative truncation effects (the elimination of the upper part of the cavity) on the optics and geometric properties and the annual energy generated by the equipment. For the CPC concentrator collectors with fully illuminated inverted V absorbers and ideal (without truncation) it was concluded that in the configuration in which the angle of angular acceptance of the CPC is equal to the apex angle of the absorber, there occurs a minimum perimeter of the reflector cavity, when the nominal concentration and the size of the absorber are constant. Regarding the CPC concentrator collectors fully illuminated with inverted V absorber and with optimized truncation, it is shown, for a concentrator of 1.2 concentration, a good related reflector surface length and opening, and a mean number of reflections and generated thermal energy that this occurs for concentrators arising from concentrators with acceptance angles among 33.75 up to 45.58 degrees. (author)

  17. Fabrication and comparison of selective, transparent optics for concentrating solar systems

    Taylor, Robert A.; Hewakuruppu, Yasitha; DeJarnette, Drew; Otanicar, Todd P.

    2015-09-01

    Concentrating optics enable solar thermal energy to be harvested at high temperature (solar) wavelengths, but highly reflective at long (thermal emission) wavelengths. If a solar system requires an analogous transparent, non-absorbing optic - i.e. a cover material which is highly transparent at short wavelengths, but highly reflective at long wavelengths - the technology is simply not available. Low-e glass technology represents a commercially viable option for this sector, but it has only been optimized for visible light transmission. Optically thin metal hole-arrays are another feasible solution, but are often difficult to fabricate. This study investigates combinations of thin film coatings of transparent conductive oxides and nanoparticles as a potential low cost solution for selective solar covers. This paper experimentally compares readily available materials deposited on various substrates and ranks them via an `efficiency factor for selectivity', which represents the efficiency of radiative exchange in a solar collector. Out of the materials studied, indium tin oxide and thin films of ZnS-Ag-ZnS represent the most feasible solutions for concentrated solar systems. Overall, this study provides an engineering design approach and guide for creating scalable, selective, transparent optics which could potentially be imbedded within conventional low-e glass production techniques.

  18. A Non-Ventilated Solar Façade Concept Based on Selective and Transparent Insulation Material Integration: An Experimental Study

    Miroslav Čekon

    2017-06-01

    Full Text Available A new solar façade concept based on transparent insulation and a selective absorber is proposed, tested and compared with conventional insulation and a non-selective type of absorber, respectively. The presented study focuses on an experimental non-ventilated solar type of façade exposed to solar radiation both in the laboratory and in outdoor tests. Due to the high solar absorbance level of the façade, high- and low-emissivity contributions were primarily analysed. All of the implemented materials were contrasted from the thermal and optical point of view. An analysis was made of both thermodynamic and steady state procedures affecting the proposed solar façade concept. Experimental full scale tests on real building components were additionally involved during summer monitoring. An indicator of the temperature response generated by solar radiation exposure demonstrates the outdoor performance of the façade is closely related to overheating phenomena. From the thermal point of view, the proposed transparent insulation and selective absorber concept corresponds to the performance of conventional thermal insulation of identical material thickness; however, the non-selective prototype only provides 50% thermal performance. The results of the solar-based experiments show that with a small-scale experimental prototype, approximately no significant difference is measured when compared with a non-selective absorber type. The only difference was achieved at the maximum of 2.5 K, when the lower temperature was obtained in the solar selective concept. At the full-scale outdoor mode, the results indicate a maximum of 3.0 K difference, however the lower temperature achieves a non-selective approach. This solar façade can actively contribute to the thermal performance of building components during periods of heating.

  19. Reducing heat loss from the energy absorber of a solar collector

    Chao, Bei Tse; Rabl, Ari

    1976-01-01

    A device is provided for reducing convective heat loss in a cylindrical radiant energy collector. It includes a curved reflective wall in the shape of the arc of a circle positioned on the opposite side of the exit aperture from the reflective side walls of the collector. Radiant energy exiting the exit aperture is directed by the curved wall onto an energy absorber such that the portion of the absorber upon which the energy is directed faces downward to reduce convective heat loss from the absorber.

  20. Investigations into alterntive substrate, absorber, and buffer layer processing for Cu(In,Ga)Se{sub 2}-based solar cells

    Tuttle, J.R.; Berens, T.A.; Keane, J. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    High-performance Cu(In,Ga)Se{sub 2}(CIGS)-based solar cells are presently fabricated within a narrow range of processing options. In this contribution, alternative substrate, absorber, and buffer layer processing is considered. Cell performance varies considerably when alternative substrates are employed. These variations are narrowed with the addition of Na via a Na{sub 2}S compound. Sputtered and electrodeposited CIGS precursors and completed absorbers show promise as alternatives to evaporation. A recrystallization process is required to improve their quality. (In,Ga){sub y}Se buffer layers contribute to cell performance above 10. Further improvements in these alternatives will lead to combined cell performance greater than 10% in the near term.

  1. Pinning down high-performance Cu-chalcogenides as thin-film solar cell absorbers: A successive screening approach

    Zhang, Yubo; Zhang, Wenqing, E-mail: wqzhang@mail.sic.ac.cn, E-mail: pzhang3@buffalo.edu [Materials Genome Institute and Department of Physics, Shanghai University, Shanghai 200444 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Youwei; Zhang, Jiawei; Xi, Lili [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Peihong, E-mail: wqzhang@mail.sic.ac.cn, E-mail: pzhang3@buffalo.edu [Materials Genome Institute and Department of Physics, Shanghai University, Shanghai 200444 (China); Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260 (United States)

    2016-05-21

    Photovoltaic performances of Cu-chalcogenides solar cells are strongly correlated with the absorber fundamental properties such as optimal bandgap, desired band alignment with window material, and high photon absorption ability. According to these criteria, we carry out a successive screening for 90 Cu-chalcogenides using efficient theoretical approaches. Besides the well-recognized CuInSe{sub 2} and Cu{sub 2}ZnSnSe{sub 4} materials, several novel candidates are identified to have optimal bandgaps of around 1.0–1.5 eV, spike-like band alignments with CdS window layer, sharp photon absorption edges, and high absorption coefficients. These new systems have great potential to be superior absorbers for photovolatic applications if their carrrier transport and defect properties are properly optimized.

  2. Augmentation of a solar still distillate yield via absorber plate coated with black nanoparticles

    A.E. Kabeel

    2017-12-01

    Full Text Available Effects of utilizing nanomaterial on the solar still productivity investigated experimentally. Cuprous oxides (CuO chosen as a nanoparticles material. The nanoparticles added to the black paint of the solar still walls to enhance the solar still performance. Experiments conducted with cuprous oxide nanoparticles weight concentrations ranged from 10% to 40%. It is found that adding nanoparticles to paint increase heat transfer rate and saline water temperature. Solar still productivity of the proposed system is higher than that for the conventional still. Results acquired that utilizing CuO nanoparticles boosted the distillate by 16% and 25% as compared to the conventional solar still (CSS at weight fraction concentration of 10% and 40%, respectively. Payback period of the distillation system for the modified still using CuO nanomaterials is about 96 days, at weight fraction 10%, which is considerable as compared by 89 days for CSS. Keywords: Nanomaterial, Solar still, Distillation, Nanoparticle

  3. An ultrathin wide-band planar metamaterial absorber based on a fractal frequency selective surface and resistive film

    Fan Yue-Nong; Cheng Yong-Zhi; Nie Yan; Wang Xian; Gong Rong-Zhou

    2013-01-01

    We propose an ultrathin wide-band metamaterial absorber (MA) based on a Minkowski (MIK) fractal frequency selective surface and resistive film. This absorber consists of a periodic arrangement of dielectric substrates sandwiched with an MIK fractal loop structure electric resonator and a resistive film. The finite element method is used to simulate and analyze the absorption of the MA. Compared with the MA-backed copper film, the designed MA-backed resistive film exhibits an absorption of 90% at a frequency region of 2 GHz–20 GHz. The power loss density distribution of the MA is further illustrated to explain the mechanism of the proposed MA. Simulated absorptions at different incidence cases indicate that this absorber is polarization-insensitive and wide-angled. Finally, further simulated results indicate that the surface resistance of the resistive film and the dielectric constant of the substrate can affect the absorbing property of the MA. This absorber may be used in many military fields

  4. Annealing effect on the structural and optical properties of Cr/α-Cr2O3 monodispersed particles based solar absorbers

    Khamlich, S.; McCrindle, R.; Nuru, Z.Y.; Cingo, N.; Maaza, M.

    2013-01-01

    Graphical abstract: A cost-effective and environmentally friendly green chemical method, the so-called aqueous chemical growth (ACG) method, was used to deposit chromium/alpha-chromium(III) oxide, Cr/α-Cr 2 O 3 , monodispersed particles, for solar absorbers applications. Highlights: ► Cr/α-Cr 2 O 3 have been deposited by the aqueous chemical growth (ACG) method. ► High temperature annealing affects the optical selectivity of the deposited particles. ► Oxygen diffusion to the interface at high temperature results in the oxidization of the substrate. - Abstract: A cost-effective and environmentally friendly green chemical method, the so-called aqueous chemical growth (ACG) method, was used to deposit chromium/alpha-chromium(III) oxide, Cr/α-Cr 2 O 3 , monodispersed particles, for solar absorbers applications. The deposited particles were annealed at various temperatures in a hydrogen atmosphere for 2 h to study the annealing temperature dependence of the structural, chemical and optical properties of the particles grown on tantalum substrates. The deposited Cr/α-Cr 2 O 3 was characterized by X-ray diffraction (XRD), attenuated total reflection (ATR), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and diffuse reflectance UV–vis–NIR spectroscopy. The XRD and ATR analysis indicated that by increasing annealing temperature, the particles crystallinity was improved and Ta 2 O 5 was formed around 600 °C, due to the fast oxygen diffusion from the deposited α-Cr 2 O 3 toward the tantalum substrate. The optical measurements show that samples annealed at 400 and 500 °C exhibit the targeted high absorbing optical characteristics of “Black chrome”, while those annealed below 400 °C and above 500 °C show a significant low absorptivity and high emissivity.

  5. Improving solar radiation absorbance of high refractory sintered ceramics by fs Ti:sapphire laser surface treatment

    Cappelli, E.; Orlando, S.; Sciti, D.; Bellucci, A.; Lettino, A.; Trucchi, D.M.

    2014-01-01

    Samples of high refractory pressure-less sintered carbide ceramics (HfC based), polished by mechanical grinding to a surface roughness R a ∼ 40 nm, have been surface treated, in vacuum, by fs Ti:sapphire laser, operating at 800 nm wavelength, 1000 Hz repetition rate and 100 fs pulse duration, at fluence varying in the range (∼6–25 J/cm 2 ), to optimize their solar radiation absorbance, in such a way that they could operate as absorber material in an innovative conversion module of solar radiation into electrical energy. To this aim, an area of approximately 9.6 cm 2 was treated by the fs laser beam. The beam strikes perpendicular to the sample, placed on a stage set in motion in the x, y, z-directions, thus generating a scanning pattern of parallel lines. The experimental conditions of laser treatment (energy fluence, speed of transition, overlapping and lateral step distance) were varied in order to optimize the radiation absorption properties of the patterned surface. In laser treated samples the absorption value is increased by about 15%, compared to the original untreated surface, up to a value of final absorbance of about 95%, all over the range of solar radiation spectrum (from UV to IR). The morphological and chemical effects of the treatment have been evaluated by SEM–EDS analysis. At very high fluence, we obtained the characteristic ablation craters and local material decomposition, while at lower fluence (in any case above the threshold) typical periodic nano-structures have been obtained, exploitable for their modified optical properties.

  6. Selective fallopian tube catheterisation in female infertility: clinical results and absorbed radiation dose

    Nakamura, K.; Ishiguchi, T.; Maekoshi, H.; Ando, Y.; Tsuzaka, M.; Tamiya, T.; Suganuma, N.; Ishigaki, T.

    1996-01-01

    Clinical results of fluoroscopic fallopian tube catheterisation and absorbed radiation doses during the procedure were evaluated in 30 infertility patients with unilateral or bilateral tubal obstruction documented on hysterosalpingography. The staged technique consisted of contrast injection through an intrauterine catheter with a vacuum cup device, ostial salpingography with the wedged catheter, and selective salpingography with a coaxial microcatheter. Of 45 fallopian tubes examined, 35 (78 %) were demonstrated by the procedure, and at least one tube was newly demonstrated in 26 patients (87 %). Six of these patients conceived spontaneously in the follow-up period of 1-11 months. Four pregnancies were intrauterine and 2 were ectopic. This technique provided accurate and detailed information in the diagnosis and treatment of tubal obstruction in infertility patients. The absorbed radiation dose to the ovary in the average standardised procedure was estimated to be 0.9 cGy. Further improvement in the X-ray equipment and technique is required to reduce the radiation dose. (orig.). With 3 figs., 3 tabs

  7. Optimization by simulation of the nature of the buffer, the gap profile of the absorber and the thickness of the various layers in CZTSSe solar cells

    Chadel, Meriem; Chadel, Asma; Moustafa Bouzaki, Mohammed; Aillerie, Michel; Benyoucef, Boumediene; Charles, Jean-Pierre

    2017-11-01

    Performances of ZnO/ZnS/CZTSSe polycrystalline thin film solar cells (Copper Zinc Tin Sulphur Selenium-solar cell) were simulated for different thicknesses of the absorber and ZnS buffer layers. Simulations were performed with SCAPS (Solar Cell Capacitance Simulator) software, starting with actual parameters available from industrial data for commercial cells processing. The influences of the thickness of the various layers in the structure of the solar cell and the gap profile of the CZTSSe absorber layer on the performance of the solar cell were studied in detail. Through considerations of recent works, we discuss possible routes to enhance the performance of CZTSSe solar cells towards a higher efficiency level. Thus, we found that for one specific thickness of the absorber layer, the efficiency of the CZTSSe solar cell can be increased when a ZnS layer replaces the usual CdS buffer layer. On the other hand, the efficiency of the solar cell can be also improved when the absorber layer presents a grad-gap. In this case, the maximum efficiency for the CZTSSe cell was found equal to 13.73%.

  8. Feature Selection and ANN Solar Power Prediction

    O’Leary, Daniel; Kubby, Joel

    2017-01-01

    A novel method of solar power forecasting for individuals and small businesses is developed in this paper based on machine learning, image processing, and acoustic classification techniques. Increases in the production of solar power at the consumer level require automated forecasting systems to minimize loss, cost, and environmental impact for homes and businesses that produce and consume power (prosumers). These new participants in the energy market, prosumers, require new artificial neural...

  9. Solar Thermal AIR Collector Based on New Type Selective Coating

    Musiy, R.Y.

    2014-01-01

    Full Text Available Based on the best for optical performance and selective coating solar thermal air collector, which operates by solar power on the principle of simultaneous ventilation and heating facilities, is designed. It can be used for vacation homes, museums, wooden churches, warehouses, garages, houses, greenhouses etc.

  10. Black Cr/a-Cr2O3 nanoparticles based solar absorbers

    Khamlich, S

    2012-01-01

    Full Text Available and attenuated total reflection, as well as UV–vis diffuse reflectance spectroscopy. The samples aged for more than 40 h at 75 °C exhibit the targeted high absorbing optical characteristic “Black chrome” while those aged for =40 h show a significant high UV–vis...

  11. Investigation of Non-Vacuum Deposition Techniques in Fabrication of Chalcogenide-Based Solar Cell Absorbers

    Alsaggaf, Ahmed

    2015-01-01

    simulating R2R process design at speeds up to 1.05 m/min. The research clarified morphological and compositional impacts of Nd:YAG laser heat-treatment on Cu(In,Ga)Se2 absorber layer to simplify the annealing step in non-vacuum environment compatible to R2R

  12. Electrodeposition of CdSe coatings on ZnO nanowire arrays for extremely thin absorber solar cells

    Majidi, Hasti [Department of Chemical and Biological Engineering, Drexel University, 3141 Chestnut St, Philadelphia, PA 19104 (United States); Baxter, Jason B., E-mail: jbaxter@drexel.ed [Department of Chemical and Biological Engineering, Drexel University, 3141 Chestnut St, Philadelphia, PA 19104 (United States)

    2011-02-15

    We report on electrodeposition of CdSe coatings onto ZnO nanowire arrays and determine the effect of processing conditions on material properties such as morphology and microstructure. CdSe-coated ZnO nanowire arrays have potential use in extremely thin absorber (ETA) solar cells, where CdSe absorbs visible light and injects photoexcited electrons into the ZnO nanowires. We show that room-temperature electrodeposition enables growth of CdSe coatings that are highly crystalline, uniform, and conformal with precise control over thickness and microstructure. X-ray diffraction and transmission electron microscopy show nanocrystalline CdSe in both hexagonal and cubic phases with grain size {approx}5 nm. Coating morphology depends on electrodeposition current density. Uniform and conformal coatings were achieved using moderate current densities of {approx}2 mA cm{sup -2} for nanowires with roughness factor of {approx}10, while lower current densities resulted in sparse nucleation and growth of larger, isolated islands. Electrodeposition charge density controls the thickness of the CdSe coating, which was exploited to investigate the evolution of the morphology at early stages of nucleation and growth. UV-vis transmission spectroscopy and photoelectrochemical solar cell measurements demonstrate that CdSe effectively sensitizes ZnO nanowires to visible light.

  13. Electrodeposition of CdSe coatings on ZnO nanowire arrays for extremely thin absorber solar cells

    Majidi, Hasti; Baxter, Jason B.

    2011-01-01

    We report on electrodeposition of CdSe coatings onto ZnO nanowire arrays and determine the effect of processing conditions on material properties such as morphology and microstructure. CdSe-coated ZnO nanowire arrays have potential use in extremely thin absorber (ETA) solar cells, where CdSe absorbs visible light and injects photoexcited electrons into the ZnO nanowires. We show that room-temperature electrodeposition enables growth of CdSe coatings that are highly crystalline, uniform, and conformal with precise control over thickness and microstructure. X-ray diffraction and transmission electron microscopy show nanocrystalline CdSe in both hexagonal and cubic phases with grain size ∼5 nm. Coating morphology depends on electrodeposition current density. Uniform and conformal coatings were achieved using moderate current densities of ∼2 mA cm -2 for nanowires with roughness factor of ∼10, while lower current densities resulted in sparse nucleation and growth of larger, isolated islands. Electrodeposition charge density controls the thickness of the CdSe coating, which was exploited to investigate the evolution of the morphology at early stages of nucleation and growth. UV-vis transmission spectroscopy and photoelectrochemical solar cell measurements demonstrate that CdSe effectively sensitizes ZnO nanowires to visible light.

  14. New NIR Absorbing DPP-based Polymer for Thick Organic Solar Cells

    Oklem, Gulce; Song, Xin; Toppare, Levent; Baran, Derya; Gunbas, Gorkem

    2018-01-01

    infrared region (NIR) for better photon harvesting in organic solar cells. It has been shown that copolymers compromising diketopyrrolopyrrole based acceptors and simple donors (thiophene or furan) achieve absorption maximum around 800 nm

  15. Dielectric compound parabolic concentrating solar collector with frustrated total internal reflection absorber

    Hull, J. R.

    Since its introduction, the concept of nonimaging solar concentrators, as exemplified by the compound parabolic concentrator (CPC) design, has greatly enhanced the ability to collect solar energy efficiently in thermal and photovoltaic devices. When used as a primary concentrator, a CPC can provide significant concentration without the complication of a tracking mechanism and its associated maintenance problems. When used as a secondary, a CPC provides higher total concentration, or for a fixed concentration, tolerates greater tracking error in the primary.

  16. Effect of thermal annealing in vacuum on the photovoltaic properties of electrodeposited Cu2O-absorber solar cell

    Dimopoulos T.

    2014-07-01

    Full Text Available Heterojunction solar cells were fabricated by electrochemical deposition of p-type, cuprous oxide (Cu2O absorber on sputtered, n-type ZnO layer. X-ray diffraction measurements revealed that the as-deposited absorber consists mainly of Cu2O, but appreciable amounts of metallic Cu and cupric oxide (CuO are also present. These undesired oxidation states are incorporated during the deposition process and have a detrimental effect on the photovoltaic properties of the cells. The open circuit voltage (VOC, short circuit current density (jSC, fill factor (FF and power conversion efficiency (η of the as-deposited cells are 0.37 V, 3.71 mA/cm2, 35.7% and 0.49%, respectively, under AM1.5G illumination. We show that by thermal annealing in vacuum, at temperatures up to 300 °C, compositional purity of the Cu2O absorber could be obtained. A general improvement of the heterojunction and bulk materials quality is observed, reflected upon the smallest influence of the shunt and series resistance on the transport properties of the cells in dark and under illumination. Independent of the annealing temperature, transport is dominated by the space-charge layer generation-recombination current. After annealing at 300 °C the solar cell parameters could be significantly improved to the values of: VOC = 0.505 V, jSC = 4.67 mA/cm2, FF = 47.1% and η = 1.12%.

  17. Monitoring of diisopropyl fluorophosphate hydrolysis by fluoride-selective polymeric films using absorbance spectroscopy

    Ramanathan, Madhumati; Wang Lin; Wild, James R.; Meyeroff, Mark E.; Simonian, Aleksandr L.

    2010-01-01

    In this study, a novel system for the detection and quantification of organofluorophosphonates (OFP) has been developed by using an optical sensing polymeric membrane to detect the fluoride ions produced upon OFP hydrolysis. Diisopropyl fluorophosphate (DFP), a structural analogue of type G chemical warfare agents such as Sarin (GB) and Soman (GD), is used as the surrogate target analyte. An optical sensing fluoride ion selective polymeric film was formulated from plasticized PVC containing aluminum(III) octaethyl porphyrin and ETH 7075 chromoionophore (Al[OEP]-ETH 7075). Selected formulations were used to detect the fluoride ions produced by the catalytic hydrolysis of DFP by the enzyme organophosphate hydrolase (OPH, EC 3.1.8.1). The changes in absorbance that corresponded to the deprotonated state of chromoionophore within the film results from simultaneous coextraction of fluoride and protons as DFP hydrolysis takes place in the solution phase in contact with the film. The developed sensing system demonstrates excellent sensitivity for concentrations as low as 0.1 μM DFP.

  18. Monitoring of diisopropyl fluorophosphate hydrolysis by fluoride-selective polymeric films using absorbance spectroscopy

    Ramanathan, Madhumati [Materials Research and Education Center, Auburn University, Auburn, AL 36849 (United States); Wang Lin [Department of Chemistry, University of Michigan, 930 North University, Ann Arbor, MI 48109 (United States); Wild, James R. [Biochemistry and Biophysics Department, Texas A and M University Texas AgriLife Research Program, College Station, TX 77843-2128 (United States); Meyeroff, Mark E. [Department of Chemistry, University of Michigan, 930 North University, Ann Arbor, MI 48109 (United States); Simonian, Aleksandr L., E-mail: simonal@auburn.edu [Materials Research and Education Center, Auburn University, Auburn, AL 36849 (United States)

    2010-05-14

    In this study, a novel system for the detection and quantification of organofluorophosphonates (OFP) has been developed by using an optical sensing polymeric membrane to detect the fluoride ions produced upon OFP hydrolysis. Diisopropyl fluorophosphate (DFP), a structural analogue of type G chemical warfare agents such as Sarin (GB) and Soman (GD), is used as the surrogate target analyte. An optical sensing fluoride ion selective polymeric film was formulated from plasticized PVC containing aluminum(III) octaethyl porphyrin and ETH 7075 chromoionophore (Al[OEP]-ETH 7075). Selected formulations were used to detect the fluoride ions produced by the catalytic hydrolysis of DFP by the enzyme organophosphate hydrolase (OPH, EC 3.1.8.1). The changes in absorbance that corresponded to the deprotonated state of chromoionophore within the film results from simultaneous coextraction of fluoride and protons as DFP hydrolysis takes place in the solution phase in contact with the film. The developed sensing system demonstrates excellent sensitivity for concentrations as low as 0.1 {mu}M DFP.

  19. Standard Guide for Selection and Use of Mathematical Methods for Calculating Absorbed Dose in Radiation Processing Applications

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This guide describes different mathematical methods that may be used to calculate absorbed dose and criteria for their selection. Absorbed-dose calculations can determine the effectiveness of the radiation process, estimate the absorbed-dose distribution in product, or supplement or complement, or both, the measurement of absorbed dose. 1.2 Radiation processing is an evolving field and annotated examples are provided in Annex A6 to illustrate the applications where mathematical methods have been successfully applied. While not limited by the applications cited in these examples, applications specific to neutron transport, radiation therapy and shielding design are not addressed in this document. 1.3 This guide covers the calculation of radiation transport of electrons and photons with energies up to 25 MeV. 1.4 The mathematical methods described include Monte Carlo, point kernel, discrete ordinate, semi-empirical and empirical methods. 1.5 General purpose software packages are available for the calcul...

  20. Study on the fabrication of silicon nanoparticles in an amorphous silicon light absorbing layer for solar cell applications

    Park, Joo Hyung; Song, Jin Soo; Lee, Jae Hee; Lee, Jeong Chul

    2012-01-01

    Hydrogenated amorphous-silicon (a-Si:H) thin-film solar cells have advantages of relatively simple technology, less material consumption, higher absorption ratio compared to crystalline silicon, and low cost due to the use of cheaper substrates rather than silicon wafers. However, together with those advantages, amorphous-silicon thin-film solar cells face several issues such as a relatively lower efficiency, a relatively wider bandgap, and the Staebler-Wronski effect (SWE) compared to other competing materials (i.e., crystalline silicon, CdTe, Cu(In x Ga (1-x) )Se 2 (CIGS), etc.). As a remedy for those drawbacks and a way to enhance the cell conversion efficiency at the same time, the employment of crystalline silicon nanoparticles (Si-NPs) in the a-Si matrix is proposed to organize the quantum-dot (QD) structure as the light-absorbing layer. This structure of the light absorbing layer consists of single-crystal Si-NPs in an a-Si:H thin-film matrix. The single-crystal Si-NPs are synthesized by using SiH 4 gas decomposition with CO 2 laser pyrolysis, and the sizes of Si-NPs are calibrated to control their bandgaps. The synthesized size-controlled Si-NPs are directly transferred to another chamber to form a QD structure by using co-deposition of the Si-NPs and the a-Si:H matrix. Transmission electron microscopy (TEM) analyses are employed to verify the sizes and the crystalline properties of the Si-NPs alone and of the Si-NPs in the a-Si:H matrix. The TEM results show successful co-deposition of size-controlled Si-NPs in the a-Si:H matrix, which is meaningful because it suggests the possibility of further enhancement of the a-Si:H solar-cell structure and of tandem structure applications by using a single element.

  1. Building-Integrated Solar Energy Devices based on Wavelength Selective Films

    Ulavi, Tejas

    A potentially attractive option for building integrated solar is to employ hybrid solar collectors which serve dual purposes, combining solar thermal technology with either thin film photovoltaics or daylighting. In this study, two hybrid concepts, a hybrid photovoltaic/thermal (PV/T) collector and a hybrid 'solar window', are presented and analyzed to evaluate technical performance. In both concepts, a wavelength selective film is coupled with a compound parabolic concentrator (CPC) to reflect and concentrate the infrared portion of the solar spectrum onto a tubular absorber. The visible portion of the spectrum is transmitted through the concentrator to either a thin film Cadmium Telluride (CdTe) solar panel for electricity generation or into the interior space for daylighting. Special attention is given to the design of the hybrid devices for aesthetic building integration. An adaptive concentrator design based on asymmetrical truncation of CPCs is presented for the hybrid solar window concept. The energetic and spectral split between the solar thermal module and the PV or daylighting module are functions of the optical properties of the wavelength selective film and the concentrator geometry, and are determined using a Monte Carlo Ray-Tracing (MCRT) model. Results obtained from the MCRT can be used in conjugation with meteorological data for specific applications to study the impact of CPC design parameters including the half-acceptance angle thetac, absorber diameter D and truncation on the annual thermal and PV/daylighting efficiencies. The hybrid PV/T system is analyzed for a rooftop application in Phoenix, AZ. Compared to a system of the same area with independent solar thermal and PV modules, the hybrid PV/T provides 20% more energy, annually. However, the increase in total delivered energy is due solely to the addition of the thermal module and is achieved at an expense of a decrease in the annual electrical efficiency from 8.8% to 5.8% due to shading by

  2. Broadband plasmonic perfect light absorber in the visible spectrum for solar cell applications

    Mudachathi, Renilkumar; Tanaka, Takuo

    2018-03-01

    The coupling of electromagnetic waves with subwavelength metal structures results in the perfect light absorption and has been extensively explored in the recent years for many possible applications like photovoltaics, sensing, photodetectors, emitters and camouflaging systems to name a few. Herein we present the design and fabrication of a broadband plasmonic light absorber using aluminum as functional material for operation in the visible frequency range. The metal structures can be tuned in size to manipulate the plasmonic resonance; thereby light absorption at any desired wavelengths could be realized. Thus the broadband light absorber in the visible spectrum is designed using metal structures of different sizes supporting non-overlapping individual resonances at regular intervals of wavelengths. The metal structures of different sizes are grouped in to a single unit cell and the absorber is fabricated by periodically arranging these unit cells in a square lattice. Light absorption of more than 90% for over a broad wavelength range of 200 nm from 425 nm to 650 nm in the visible spectrum is demonstrated.

  3. An introduction to selective surfaces for solar applications

    Neal, W. E. J.

    1983-12-01

    The desired characteristics of spectrally selective surfaces for solar thermal applications include a high-level absorption of radiation in the solar region of the spectrum (from 0.3 to 2.5 microns) combined with a low value of emission in the IR region (greater than two microns). There are three energy collector temperature ranges for specific solar applications, taking into account a range from 25 to 40 C for swimming pools, a range from 40 to 150 C for space and water heating and air conditioning, and temperatures above 150 C for the production of steam and the generation of electricity. Flat plate and low concentrating collectors with suitable selective surfaces can be employed in connection with the first two temperature ranges. Various types of selective surfaces are presented in a table, giving attention to the absorptive properties for solar radiation and the emissive properties in the IR region.

  4. Energy and exergy analysis of a new flat-plate solar air heater having different obstacles on absorber plates

    Akpinar, Ebru Kavak; Kocyigit, Fatih

    2010-01-01

    This study experimentally investigates performance analysis of a new flat-plate solar air heater (SAH) with several obstacles (Type I, Type II, Type III) and without obstacles (Type IV). Experiments were performed for two air mass flow rates of 0.0074 and 0.0052 kg/s. The first and second laws of efficiencies were determined for SAHs and comparisons were made among them. The values of first law efficiency varied between 20% and 82%. The values of second law efficiency changed from 8.32% to 44.00%. The highest efficiency were determined for the SAH with Type II absorbent plate in flow channel duct for all operating conditions, whereas the lowest values were obtained for the SAH without obstacles (Type IV). The results showed that the efficiency of the solar air collectors depends significantly on the solar radiation, surface geometry of the collectors and extension of the air flow line. The largest irreversibility was occurring at the SAH without obstacles (Type IV) collector in which collector efficiency is smallest. At the end of this study, the energy and exergy relationships are delivered for different SAHs.

  5. Modified Back Contact Interface of CZTSe Thin Film Solar Cells: Elimination of Double Layer Distribution in Absorber Layer.

    Zhang, Zhaojing; Yao, Liyong; Zhang, Yi; Ao, Jianping; Bi, Jinlian; Gao, Shoushuai; Gao, Qing; Jeng, Ming-Jer; Sun, Guozhong; Zhou, Zhiqiang; He, Qing; Sun, Yun

    2018-02-01

    Double layer distribution exists in Cu 2 SnZnSe 4 (CZTSe) thin films prepared by selenizing the metallic precursors, which will degrade the back contact of Mo substrate to absorber layer and thus suppressing the performance of solar cell. In this work, the double-layer distribution of CZTSe film is eliminated entirely and the formation of MoSe 2 interfacial layer is inhibited successfully. CZTSe film is prepared by selenizing the precursor deposited by electrodeposition method under Se and SnSe x mixed atmosphere. It is found that the insufficient reaction between ZnSe and Cu-Sn-Se phases in the bottom of the film is the reason why the double layer distribution of CZTSe film is formed. By increasing Sn content in the metallic precursor, thus making up the loss of Sn because of the decomposition of CZTSe and facilitate the diffusion of liquid Cu 2 Se, the double layer distribution is eliminated entirely. The crystallization of the formed thin film is dense and the grains go through the entire film without voids. And there is no obvious MoSe 2 layer formed between CZTSe and Mo. As a consequence, the series resistance of the solar cell reduces significantly to 0.14 Ω cm 2 and a CZTSe solar cell with efficiency of 7.2% is fabricated.

  6. Feature Selection and ANN Solar Power Prediction

    Daniel O’Leary

    2017-01-01

    Full Text Available A novel method of solar power forecasting for individuals and small businesses is developed in this paper based on machine learning, image processing, and acoustic classification techniques. Increases in the production of solar power at the consumer level require automated forecasting systems to minimize loss, cost, and environmental impact for homes and businesses that produce and consume power (prosumers. These new participants in the energy market, prosumers, require new artificial neural network (ANN performance tuning techniques to create accurate ANN forecasts. Input masking, an ANN tuning technique developed for acoustic signal classification and image edge detection, is applied to prosumer solar data to improve prosumer forecast accuracy over traditional macrogrid ANN performance tuning techniques. ANN inputs tailor time-of-day masking based on error clustering in the time domain. Results show an improvement in prediction to target correlation, the R2 value, lowering inaccuracy of sample predictions by 14.4%, with corresponding drops in mean average error of 5.37% and root mean squared error of 6.83%.

  7. Panchromatic response composed of hybrid visible-light absorbing polymers and near-IR absorbing dyes for nanocrystalline TiO{sub 2}-based solid-state solar cells

    Lee, Hyo Joong; Graetzel, Michael; Nazeeruddin, Md. Khaja [Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Swiss Federal Institute of Technology, CH-1015 Lausanne (Switzerland); Leventis, Henry C.; Haque, Saif A. [Department of Chemistry, Imperial College of Science Technology and Medicine, London SW72AZ (United Kingdom); Torres, Tomas [Departamento de Quimica Organica, Universidad Autonoma de Madrid (UAM), 28049 Madrid (Spain)

    2011-01-01

    In pursuit of panchromatic sensitizers for mesoporous TiO{sub 2}-based solid-state solar cells, a near-IR absorbing zinc phthalocyanine dye (coded TT1) was firstly adsorbed over relatively thin ({proportional_to}1 {mu}m) TiO{sub 2} mesoporous films and then a visible-light absorbing polymer [regioregular poly(3-hexylthiophene), P3HT] was incorporated into the mesopores as both a second sensitizer and a solid hole conductor. After optimizing some experimental parameters, these hybrid solid-state cells exhibited a clear panchromatic response, and an overall conversion efficiency of around 1% at full sun intensity. (author)

  8. Behavior of Electrochemically Prepared CuInSe2 as Photovoltaic Absorber in thin Film Solar Cells

    Guillen, C; Martinez, M.A.; Dona, J. M.; Herrero, J; Gutierrez, M. T.

    2000-01-01

    Two different objectives have been pursued in the present investigation: 1) optimization of the CuInSe, preparation parameters from electrodeposited precursors, and 2) evaluation of their photovoltaic behavior by preparing and enhancing Mo/CuInSe,/CdS/TCO devices. When Cu-In-Se precursors are directly electrodeposited, the applied potential fit is essential to improve the photovoltaic performance. Suitable absorbers have been also obtained by evaporating an In layer onto electrodeposited Cu-Se precursors. In this case, the substrate temperature during evaporation determines the CuInSe, quality. Similar results have been reached by substituting typical Mo-coated glass substrates by flexible Mo foils. Different TCO tested (ZnO and ITO) have been found equivalent as front electrical contact in the devices. Solar cell performance can be improved by annealing in air at 200 degree centigree. (Author) 46 refs

  9. XRD total scattering of the CZTS nanoparticle absorber layer for the thin film solar cells

    Symonowicz, Joanna; Jensen, Kirsten M. Ø.; Engberg, Sara Lena Josefin

    Cu2ZnSnS4 (CZTS) thin film solar cells are cheap, non-toxic and present an efficiency up to 9,2% [1]. They can be easily manufactured by the deposition of the nanoparticle ink as a thin film followed by a thermal treatment to obtain large grains [2]. Therefore, CZTS has the potential...... to revolutionize the solar energy market. However, to commercialize CZTS nanoparticle thin films, the efficiency issues must yet be resolved. In order to do so, it is vital to understand in detail their nanoscale atomic structure. CZTS crystallize in the kesterite structure, where Cu and Zn is distributed between......-ray Diffraction data with X-ray total scattering with Pair Distribution Function analysis. Powder neutron diffraction will furthermore allow characterization of the cation disorder on the metal sites in the kesterite structure. The nanoparticle ink is also characterized by XRD, EDS, and Raman spectroscopy...

  10. New NIR Absorbing DPP-based Polymer for Thick Organic Solar Cells

    Oklem, Gulce

    2018-02-05

    infrared region (NIR) for better photon harvesting in organic solar cells. It has been shown that copolymers compromising diketopyrrolopyrrole based acceptors and simple donors (thiophene or furan) achieve absorption maximum around 800 nm. In this study, the selenophene based donor units coupled with diketopyrrolopyrrole acceptor unit based polymer (PFDPPSe) was synthesized with an absorption maximum at 830 nm and absorption onset of 930 nm. The optimized organic solar cells with PFDDPSe: PC71BM active layer blends of 210 nm showed maximum PCE of 6.16 % (ave. 6.02 %) via solvent additive engineering with inverted device structure. Charge transport, recombination loss mechanism, and morphology are systematically studied. These results demonstrate that highly efficient NIR polymer can be achieved by the introduction of selenophene and a suitable solvent additive process suitable for NIR organic solar cells. PFDPPSe is also one of the rare examples of a polymer with a PCE over 6% that does not contain any thiophene-based unit in its backbone.

  11. Cost reductions in photovoltaics - Solar selection

    Rentzing, S.

    2009-01-01

    This article discusses the effect of the economic recession on the solar industry. Whilst certain companies fight to survive, margins are sinking and badly-positioned companies and expensive technologies are being pushed out of the market. The author goes on to take a look at business figures and the throttling back of production, even in China. Sinking module prices and sufficient supplies of silicon are commented on. Top companies that provide good value for money are noted and markets such as that in the USA will, according to the author, develop further, thanks to government funding

  12. Development of Solar Drying Model for Selected Cambodian Fish Species

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R 2), chi-square (χ 2) test, and root-mean-square error (RMSE), the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing. PMID:25250381

  13. Development of Solar Drying Model for Selected Cambodian Fish Species

    Anna Hubackova

    2014-01-01

    Full Text Available A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R2, chi-square (χ2 test, and root-mean-square error (RMSE, the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  14. PERFORMANCE CHARACTERISTICS OF PARABOLIC SOLAR COLLECTOR WATER HEATER SYSTEM FITTED WITH NAIL TWISTED TAPES ABSORBER

    K. SYED JAFAR

    2017-03-01

    Full Text Available In this paper, the experimental heat transfer, friction loss and thermal performance data for water flowing through the absorber tube fitted with two different twisted tape configurations in parabolic trough collector (PTC are presented. In the present work, a relative experimental study is carried out to investigate the performance of a PTC influenced by heat transfer through fluidabsorber wall mixing mechanism. The major findings of this experiment show that heat transport enhancement in the nail twisted tape collector perform significantly better than plain twisted tapes and also show that the smallest twisted tape ratio enhances the system performance remarkably maximizing the collector efficiency. The results suggest that the twisted tape and nail twisted tape would be a better option for high thermal energy collection in laminar region of the PTC system.

  15. Solar power conversion system with directionally- and spectrally-selective properties based on a reflective cavity

    Boriskina, Svetlana; Kraemer, Daniel; McEnaney, Kenneth; Weinstein, Lee A.; Chen, Gang

    2018-03-13

    Solar power conversion system. The system includes a cavity formed within an enclosure having highly specularly reflecting in the IR spectrum inside walls, the enclosure having an opening to receive solar radiation. An absorber is positioned within the cavity for receiving the solar radiation resulting in heating of the absorber structure. In a preferred embodiment, the system further contains an energy conversion and storage devices thermally-linked to the absorber by heat conduction, convection, far-field or near-field thermal radiation.

  16. Synthesis of active absorber layer by dip-coating method for perovskite solar cell

    Singh, Rahul; Noor, I. M.; Singh, Pramod K.; Bhattacharya, B.; Arof, A. K.

    2018-04-01

    In this paper, we develop the hybrid perovskite-based n-i-p solar cell using a simple, fast and low-cost dip-coating method. Hot solution and the pre-annealed substrate are used for coating the perovskite thin film by this method this is further used for studying its structural and electrical properties. UV-vis spectroscopy is carried out for calculating the band gap of the hybrid perovskite layer which is ∼1.6 eV. X-ray spectroscopy confirms that the formation of hybrid perovskite layer. The profilometer is used to study the surface roughness and also for measuring the thickness of the perovskite layer with varying substrate temperature. The optimized sample was further used for cross-sectional SEM image to verify the thickness measured from the profiler. The electrical parameter of JV characteristic with varying temperature is tabulated in the table. Whereas, the perovskite sensitized solar cell exhibits highest short circuit current density, Jsc of 11 mA cm-2, open circuit voltage, Voc of 0.87 V, fill factor of 0.55 and efficiency, η of >5%.

  17. Wavelength-dependent induction of UV absorbing mycosporine-like amino acids in the red alga Chondrus crispus under natural solar radiation

    Krabs, G; Bischof, K; Hanelt, D; Karsten, U; Wiencke, C

    2002-01-01

    Polychromatic response spectra for the induction of UV absorbing mycosporine-like amino acids (MAAs) were calculated after exposing small thalli of the red alga Chondrus crispus under various cut-off filters to natural solar radiation on the North Sea island Helgoland, Germany. The laboratory-grown

  18. Performance study of solar stills with various absorbing materials and a sensible heat storage medium

    Perumal Prakash

    2016-01-01

    Full Text Available In this paper, the productivity of the solar stills is enhanced by placing different wick materials on the inner walls of the basin. The experiments are conducted with three different wick materials, namely cotton cloth, jute cloth, and sponges. The wick materials are painted with black to increase the absorptivity. The productivity of the still with cotton cloth, jute cloth, and sponges are 38.56%, 31.37%, and 24.50%, respectively, more than the conventional still. The stills are also tested with wicks and pebbles and compared with the conventional still. The productivity of the still with cotton cloth with pebbles, jute cloth with pebbles and sponge with pebbles are 55.66%, 43.68%, and 33.33%, respectively, more than the conventional still.

  19. Hydrocarbon pyrolysis reactor experimentation and modeling for the production of solar absorbing carbon nanoparticles

    Frederickson, Lee Thomas

    Much of combustion research focuses on reducing soot particulates in emissions. However, current research at San Diego State University (SDSU) Combustion and Solar Energy Laboratory (CSEL) is underway to develop a high temperature solar receiver which will utilize carbon nanoparticles as a solar absorption medium. To produce carbon nanoparticles for the small particle heat exchange receiver (SPHER), a lab-scale carbon particle generator (CPG) has been built and tested. The CPG is a heated ceramic tube reactor with a set point wall temperature of 1100-1300°C operating at 5-6 bar pressure. Natural gas and nitrogen are fed to the CPG where natural gas undergoes pyrolysis resulting in carbon particles. The gas-particle mixture is met downstream with dilution air and sent to the lab scale solar receiver. To predict soot yield and general trends in CPG performance, a model has been setup in Reaction Design CHEMKIN-PRO software. One of the primary goals of this research is to accurately measure particle properties. Mean particle diameter, size distribution, and index of refraction are calculated using Scanning Electron Microscopy (SEM) and a Diesel Particulate Scatterometer (DPS). Filter samples taken during experimentation are analyzed to obtain a particle size distribution with SEM images processed in ImageJ software. These results are compared with the DPS, which calculates the particle size distribution and the index of refraction from light scattering using Mie theory. For testing with the lab scale receiver, a particle diameter range of 200-500 nm is desired. Test conditions are varied to understand effects of operating parameters on particle size and the ability to obtain the size range. Analysis of particle loading is the other important metric for this research. Particle loading is measured downstream of the CPG outlet and dilution air mixing point. The air-particle mixture flows through an extinction tube where opacity of the mixture is measured with a 532 nm

  20. Potential of HfN, ZrN, and TiH as hot carrier absorber and Al2O3/Ge quantum well/Al2O3 and Al2O3/PbS quantum dots/Al2O3 as energy selective contacts

    Shrestha, Santosh; Chung, Simon; Liao, Yuanxun; Wang, Pei; Cao, Wenkai; Wen, Xiaoming; Gupta, Neeti; Conibeer, Gavin

    2017-08-01

    The hot carrier (HC) solar cell is one of the most promising advanced photovoltaic concepts. It aims to minimise two major losses in single junction solar cells due to sub-band gap loss and thermalisation of above band gap photons by using a small bandgap absorber, and, importantly, collecting the photo-generated carriers before they thermalise. In this paper we will present recent development of the two critical components of the HC solar cell, i.e., the absorber and energy selective contacts (ESCs). For absorber, fabrication and carrier cooling rates in potential bulk materials — hafnium nitride, zirconium nitride, and titanium hydride are presented. Results of ESCs employing double barrier resonant tunneling structures Al2O3/Ge quantum well (QW)/Al2O3 and Al2O3/PbS quantum dots (QDs)/Al2O3 are also presented. These results are expected to guide further development of practical HC solar cell devices.

  1. Optical and Structural Characterization of Nickel Coatings for Solar Collector Receivers

    Pratesi, S.; Sani, E.; De Lucia, M.

    2014-01-01

    The development of spectrally selective materials is gaining an increasing role in solar thermal technology. The ideal spectrally selective solar absorber requires high absorbance at the solar spectrum wavelengths and low emittance at the wavelengths of thermal spectrum. Selective coating represents a promising route to improve the receiver efficiency for parabolic trough collectors (PTCs). In this work, we describe an intermediate step in the fabrication of black-chrome based solar absorbers...

  2. Reconstructing the energy band electronic structure of pulsed laser deposited CZTS thin films intended for solar cell absorber applications

    Pandiyan, Rajesh; Oulad Elhmaidi, Zakaria; Sekkat, Zouheir; Abd-lefdil, Mohammed; El Khakani, My Ali

    2017-02-01

    We report here on the use of pulsed KrF-laser deposition (PLD) technique for the growth of high-quality Cu2ZnSnS4 (CZTS) thin films onto Si, and glass substrates without resorting to any post sulfurization process. The PLD-CZTS films were deposited at room temperature (RT) and then subjected to post annealing at different temperatures ranging from 200 to 500 °C in Argon atmosphere. The X-ray diffraction and Raman spectroscopy confirmed that the PLD films crystallize in the characteristic kesterite CZTS structure regardless of their annealing temperature (Ta), but their crystallinity is much improved for Ta ≥ 400 °C. The PLD-CZTS films were found to exhibit a relatively dense morphology with a surface roughness (RMS) that increases with Ta (from ∼14 nm at RT to 70 nm at Ta = 500 °C with a value around 40 nm for Ta = 300-400 °C). The optical bandgap of the PLD-CZTS films, was derived from UV-vis transmission spectra analysis, and found to decrease from 1.73 eV for non-annealed films to ∼1.58 eV for those annealed at Ta = 300 °C. These band gap values are very close to the optimum value needed for an ideal solar cell absorber. In order to achieve a complete reconstruction of the one-dimensional energy band structure of these PLD-CZTS absorbers, we have combined both XPS and UPS spectroscopies to determine their chemical bondings, the position of their valence band maximum (relative to Fermi level), and their work function values. This enabled us to sketch out, as accurately as possible, the band alignment of the heterojunction interface formed between CZTS and both CdS and ZnS buffer layer materials.

  3. Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

    Bedair, Salah M. [North Carolina State Univ., Raleigh, NC (United States); Hauser, John R. [North Carolina State Univ., Raleigh, NC (United States); Elmasry, Nadia [North Carolina State Univ., Raleigh, NC (United States); Colter, Peter C. [North Carolina State Univ., Raleigh, NC (United States); Bradshaw, G. [North Carolina State Univ., Raleigh, NC (United States); Carlin, C. Z. [North Carolina State Univ., Raleigh, NC (United States); Samberg, J. [North Carolina State Univ., Raleigh, NC (United States); Edmonson, Kenneth [Spectrolab, Inc., Sylmar, CA (United States)

    2012-07-31

    We report on a joint research program between NCSU and Spectrolab to develop an upright multijunction solar cell structure with a potential efficiency exceeding the current record of 41.6% reported by Spectrolab. The record efficiency Ge/GaAs/InGaP triple junction cell structure is handicapped by the fact that the current generated by the Ge cell is much higher than that of both the middle and top cells. We carried out a modification of the record cell structure that will keep the lattice matched condition and allow better matching of the current generated by each cell. We used the concept of strain balanced strained layer superlattices (SLS), inserted in the i-layer, to reduce the bandgap of the middle cell without violating the desirable lattice matched condition. For the middle GaAs cell, we have demonstrated an n-GaAs/i-(InGaAs/GaAsP)/p-GaAs structure, where the InxGa1-xAs/GaAs1-yPy SLS is grown lattice matched to GaAs and with reduced bandgap from 1.43 eV to 1.2 eV, depending upon the values of x and y.

  4. Organic wavelength selective mirrors for luminescent solar concentrators

    Verbunt, P.P.C.; Debije, M.G.; Broer, D.J.; Bastiaansen, C.W.M.; Boer, de D.K.G.; Wehrspohn, R.; Gombert, A.

    2012-01-01

    Organic polymeric chiral nematic liquid crystalline (cholesteric) wavelength selective mirrors can increase the efficiency of luminescent solar concentrators (LSCs) when they are illuminated with direct sunlight normal to the device. However, due to the angular dependence of the reflection band, at

  5. Proposal of a fluid flow layout to improve the heat transfer in the active absorber surface of solar central cavity receivers

    Montes, M.J.; Rovira, A.; Martínez-Val, J.M.; Ramos, A.

    2012-01-01

    The main objective of concentrated solar power is to increase the thermal energy of a fluid, for the fluid to be used, for example, in a power cycle to generate electricity. Such applications present the requirement of appropriately designing the receiver active absorber surface, as the incident radiation flux can be very high. Besides that, the solar image in the receiver is not uniform, so conventional boilers designs are not well suited for these purposes. That point is particularly critical in solar central receivers systems (CRS), where concentrated solar flux is usually above 500 kW/m 2 , causing thermal and mechanical stress in the absorber panels. This paper analyzes a new thermofluidynamic design of a solar central receiver, which optimizes the heat transfer in the absorber surface. This conceptual receiver presents the following characteristics: the fluid flow pattern is designed according to the radiation flux map symmetry, so more uniform fluid temperatures at the receiver outlet are achieved; the heat transfer irreversibilities are reduced by circulating the fluid from the lower temperature region to the higher temperature region of the absorber surface; the width of each pass is adjusted to the solar flux gradient, to get lower temperature differences between the side tubes of the same pass; and the cooling requirement is ensured by means of adjusting the fluid flow velocity per tube, taking into account the pressure drop. This conceptual scheme has been applied to the particular case of a molten salt single cavity receiver, although the configuration proposed is suitable for other receiver designs and working fluids. - Highlights: ► The solar receiver design proposed optimizes heat transfer in the absorber surface. ► The fluid flow pattern is designed according to the solar flux map symmetry at noon. ► The fluid circulates from the lower to the higher temperature regions. ► The width of each pass is adjusted to the solar flux gradient.

  6. Microstructure of absorber layers in CdTe/CdS solar cells

    Cousins, M.A.

    2001-04-01

    This work concerns the microstructure of CSS-grown CdTe layers used for CdTe/CdS solar cells. Particular attention is given to how the development of microstructure on annealing with CdCl 2 may correlate with increases in efficiency. By annealing pressed pellets of bulk CdTe powder, it is shown that microstructural change does occur on heating the material, enhanced by the inclusion of CdCl 2 flux. However, the temperature required to cause significant effects is demonstrated to be higher than that at which heavy oxidation takes place. The dynamics of this oxidation are also examined. To investigate microstructural evolution in thin-films of CdTe, bi-layers of CdTe and CdS are examined by bevelling, thus revealing the microstructure to within ∼1 μm of the interface. This allows optical microscopy and subsequent image analysis of grain structure. The work shows that the grain-size, which is well described by the Rayleigh distribution, varies linearly throughout the layer, but is invariant under CdCl 2 treatment. Electrical measurements on these bi-layers, however, showed increased efficiency, as is widely reported. This demonstrates that the efficiency of these devices is not dictated by the bulk microstructure. Further, the region within 1 μm of the interface, of similar bi-layers to above, is examined by plan-view TEM. This reveals five-fold grain-growth on CdCl 2 treatment. Moreover, these grains show a considerably smaller grain size than expected from extrapolating the linear trend in the bulk. These observations are explained in terms of the pinning of the CdTe grain size to the underlying CdS, and the small grain size this causes. A simple model was proposed for a link between the grain-growth to the efficiency improvement. The study also examines the behaviour of defects within grains upon CdCl 2 treatment provided the first direct evidence of recovery on CdCl 2 treatment in this system. Finally, a computer model is presented to describe the evolution of

  7. Study on the Instability of Two-Phase Flow in the Heat-Absorbing Tube of Trough Solar Collector

    Ying Zhang

    2017-01-01

    Full Text Available The Marangoni effect and Rayleigh-Benard effect in the two-phase region of solar trough heat-absorbing tube are simulated by FTM (front tracking method. Considering the Marangoni effect alone, although surface tension gradient and surface tension affect the interface wave, the two effects have different characteristics. The surface tension gradient caused by the temperature gradient is one of the factors that swing the interface. The amplitude attenuation of the interface wave decreases with the increase of the Marangoni number (Ma. In general, the surface tension gradient enhances the convection opposite to the temperature gradient. Under the gravity field, the Rayleigh-Benard effect influences the development of the vortex structure in the flow field, which in turn affects the velocity gradient near the interface to influence the evolution of the interface fluctuation. In a small Rayleigh number (Ra, the buoyancy convection reduces the velocity gradient, thus suppressing the evolution of the interfacial wave. In the range of Ra  4.0E4, the situation is just the opposite. The larger the Ra is, the stronger the promoting effect is.

  8. Efficiency enhancement of perovskite solar cells using structural and morphological improvement of CH3NH3PbI3 absorber layers

    Alidaei, Maryam; Izadifard, Morteza; Ghazi, Mohammad E.; Ahmadi, Vahid

    2018-01-01

    Perovskite solar cells have been heavily investigated due to their unique properties such as high power conversion efficiency (PCE), low-cost fabrication by solution processes, high diffusion length, large absorption coefficient, and direct and tunable band gap. PCE of perovskite devices is strongly dependent on the absorber layer properties such as morphology, crystallinity, and compactness, which are required to be optimized. In this work, the CH3NH3PbI3 (170-480 nm) absorber layers with various methylammonium iodine (MAI) concentrations (7, 10, 20 and 40 mg ml-1) and perovskite solar cells with the fluorine-doped tin oxide (400 nm)/C-TiO2 (30 nm)/Meso-TiO2 (400 nm)/CH3NH3PbI3 (170-480 nm)/P3HT (30 nm)/Au (100 nm) structure were fabricated. A two-step solution process was used for deposition of the CH3NH3PbI3 absorber layers. The morphology, crystal structure, and optical properties of the perovskite layer grown on glass and also the photovoltaic properties of the fabricated solar cells were studied. The results obtained showed that by controlling the deposition conditions, due to the reduction in charge recombination, PCE enhancement of the perovskite solar cell (up to 11.6%) was accessible.

  9. A thermal-optical analysis comparison between symmetric tubular absorber compound parabolic concentrating solar collector with and without envelope

    Tchinda, R.

    2005-11-01

    Equations describing the heat transfer in symmetric, compound parabolic concentrating solar collectors (CPCs) with and without envelope have been established. The model takes into account the non linear behavior of these two systems. A theoretical numerical model has been developed to outline the effect of the envelope on the thermal and optical performance of CPCs. The effects of the flow rate, the plate length, the selective coating, etc. are studied. The over-all thermal loss coefficient and the enclosure absorption factor for both types are defined. It is found that the efficient configuration has an envelope. Theoretical computed values are in good agreement with the experimental values published in the literature. (author)

  10. Intermixing at the heterointerface between ZnS /Zn(S,O) bilayer buffer and CuInS2 thin film solar cell absorber

    Bär, M.; Ennaoui, A.; Klaer, J.; Kropp, T.; Sáez-Araoz, R.; Lehmann, S.; Grimm, A.; Lauermann, I.; Loreck, Ch.; Sokoll, St.; Schock, H.-W.; Fischer, Ch.-H.; Lux-Steiner, M. C.; Jung, Ch.

    2006-09-01

    The application of Zn compounds as buffer layers was recently extended to wide-gap CuInS2 (CIS) based thin-film solar cells. Using an alternative chemical deposition route for the buffer preparation aiming at the deposition of a single-layer, nominal ZnS buffer without the need for any toxic reactants such as hydrazine has helped us to achieve a similar efficiency as respective CdS-buffered reference devices. After identifying the deposited Zn compound, as ZnS /Zn(S,O) bilayer buffer in former investigations [M. Bär et al., J. Appl. Phys. 99, 123503 (2006)], this time the focus lies on potential diffusion/intermixing processes at the buffer/absorber interface possibly, clarifying the effect of the heat treatment, which drastically enhances the device performance of respective final solar cells. The interface formation was investigated by x-ray photoelectron and x-ray excited Auger electron spectroscopy. In addition, photoelectron spectroscopy (PES) measurements were also conducted using tunable monochromatized synchrotron radiation in order to gain depth-resolved information. The buffer side of the buffer/absorber heterointerface was investigated by means of the characterization of Zn(S ,O)/ZnS/CIS structures where the ZnS /Zn(S,O) bilayer buffer was deposited successively by different deposition times. In order to make the (in terms of PES information depth) deeply buried absorber side of the buffer/absorber heterointerface accessible for characterization, in these cases the buffer layer was etched away by dilute HClaq. We found indications that while (out-leached) Cu from the absorber layer forms together with the educts in the chemical bath a [Zn(1-Z ),Cu2Z]S-like interlayer between buffer and absorber, Zn is incorporated in the uppermost region of the absorber. Both effects are strongly enhanced by postannealing the Zn(S ,O)/ZnS/CIS samples. However, it was determined that the major fraction of the Cu and Zn can be found quite close to the heterointerface in

  11. Solar energy collector

    Brin, Raymond L.; Pace, Thomas L.

    1978-01-01

    The invention relates to a solar energy collector comprising solar energy absorbing material within chamber having a transparent wall, solar energy being transmitted through the transparent wall, and efficiently absorbed by the absorbing material, for transfer to a heat transfer fluid. The solar energy absorbing material, of generally foraminous nature, absorbs and transmits the solar energy with improved efficiency.

  12. Chromium Trioxide Hole-Selective Heterocontacts for Silicon Solar Cells.

    Lin, Wenjie; Wu, Weiliang; Liu, Zongtao; Qiu, Kaifu; Cai, Lun; Yao, Zhirong; Ai, Bin; Liang, Zongcun; Shen, Hui

    2018-04-25

    A high recombination rate and high thermal budget for aluminum (Al) back surface field are found in the industrial p-type silicon solar cells. Direct metallization on lightly doped p-type silicon, however, exhibits a large Schottky barrier for the holes on the silicon surface because of Fermi-level pinning effect. As a result, low-temperature-deposited, dopant-free chromium trioxide (CrO x , x solar cell as a hole-selective contact at the rear surface. By using 4 nm CrO x between the p-type silicon and Ag, we achieve a reduction of the contact resistivity for the contact of Ag directly on p-type silicon. For further improvement, we utilize a CrO x (2 nm)/Ag (30 nm)/CrO x (2 nm) multilayer film on the contact between Ag and p-type crystalline silicon (c-Si) to achieve a lower contact resistance (40 mΩ·cm 2 ). The low-resistivity Ohmic contact is attributed to the high work function of the uniform CrO x film and the depinning of the Fermi level of the SiO x layer at the silicon interface. Implementing the advanced hole-selective contacts with CrO x /Ag/CrO x on the p-type silicon solar cell results in a power conversion efficiency of 20.3%, which is 0.1% higher than that of the cell utilizing 4 nm CrO x . Compared with the commercialized p-type solar cell, the novel CrO x -based hole-selective transport material opens up a new possibility for c-Si solar cells using high-efficiency, low-temperature, and dopant-free deposition techniques.

  13. Sodium antimony sulfide (NaSbS2: Turning an unexpected impurity into a promising, environmentally friendly novel solar absorber material

    Siti Utari Rahayu

    2016-11-01

    Full Text Available We present a novel absorber material—NaSbS2—for solar cells. NaSbS2 is formed as an unexpected byproduct in the chemical synthesis of Sb2S3. However, NaSbS2 has many attractive features for a solar material. Here single phase NaSbS2 nanoparticles were synthesized through solution processing. NaSbS2 semiconductor-sensitized solar cells were demonstrated for the first time. The best cell yielded Jsc = 10.76 mA/cm2, Voc = 0.44 V, FF = 48.6%, and efficiency η = 2.30% under 1 sun. At the reduced 0.1 sun, the η increased to 3.18%—a respectable η for a new solar material.

  14. Determination of space charge region width and diffusion length in Cu(In,Ga)(S,Se)2 absorber from solar cell spectral characteristic

    Tivanov, M.; Mazanik, A.; Drozdov, N.; Zaretskaya, E.

    2010-01-01

    Full text : The space-charge region width and diffusion length of minority charge carriers in the base region (Cu(In,Ga)(S,Se) 2 absorber) are the most important parameters of the solar cell. These parameters determine the efficiency of a solar cell therefore the problem of their control is essential. In this work it is present simple non-destructive method of extracting the parameters of Cu(In,Ga)(S,Se) 2 -based solar cell (space-charge region width and diffusion length of minority charge carriers in Cu(In,Ga)(S,Se) 2 absorber) from the analysis of solar cell spectral photoresponse. The method is based on one-dimensional model of a solar cell and on the change of in-depth distribution of the photogenerated carriers in the solar cell and, hence, on the change of its photoresponse with the wave-length variation. The following assumptions are accepted: the reflection of charge carriers from a back contact and the ''drawing'' field in the quasi-neutral area of the absorber layers are absent, window and buffer layers are transparent in the analyzed part of photoresponse spectrum, the injection level of minority charge carriers is low, the recombination losses at the metallurgical p-n-junction interface of the studied photosensitive structure linearly depend on the photocurrent density. For the calculation it is necessary to obtain the following set of the experimental data: the spectral density of incident radiation, the spectral dependence of photocurrent or photovoltage of the studied photosensitive structure, the spectral dependences of optical absorption coefficient and reflectance.

  15. Thermal study of a residential water solar heating system with two different absorbing surface configurations; Estudo termico de um sistema solar de aquecimento de agua residencial para duas configuracoes de superficie absorvedora

    Abreu, Rivaldo Ferreira

    2009-10-15

    A solar collector to be used in a system for heating water for bathing, whose main characteristics are its low cost and easy manufacturing and assembly is presented. The absorbing surface of the collector is formed by an aluminum plate with eight flaps where they lodge PVC pipes. The catchment area of solar radiation corresponds to 1.3 meters. The collector box was made of wood, it is covered by transparent glass and thermal insulation of tire chips and expanded polystyrene (EPS). Absorber tubes were connected in parallel through the use of PVC fittings and fixed to the plate by the use of metal poles and rivets. The entire absorber received paint fiat black for better absorption of sunlight. The system worked on a thermosyphon assembly and absorber of the collector has been tested in two configurations: with the tubes facing up, directly exposed to the impact of sunlight and facing down, exchanging heat with the plate by conduction. The most efficient configuration for the connect purpose was determined. The solar collector was connected to a thermal reservoir, also alternative, low-cost forming the system of solar water heating. We evaluated thermal parameters that proved the viability of the heating system studied. (author)

  16. Reconstructing the energy band electronic structure of pulsed laser deposited CZTS thin films intended for solar cell absorber applications

    Pandiyan, Rajesh [Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel–Boulet, C.P. 1020, Varennes, QC J3X-1S2 (Canada); Oulad Elhmaidi, Zakaria [Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel–Boulet, C.P. 1020, Varennes, QC J3X-1S2 (Canada); University of Mohammed V, Faculty of Sciences, Materials Physics Laboratory, B.P. 1014 Rabat (Morocco); Sekkat, Zouheir [Optics & Photonics Center, Moroccan Foundation for Advanced Science, Innovation and Research, Rabat (Morocco); Abd-lefdil, Mohammed [University of Mohammed V, Faculty of Sciences, Materials Physics Laboratory, B.P. 1014 Rabat (Morocco); El Khakani, My Ali, E-mail: elkhakani@emt.inrs.ca [Institut National de la Recherche Scientifique, Centre-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel–Boulet, C.P. 1020, Varennes, QC J3X-1S2 (Canada)

    2017-02-28

    Highlights: • High quality CZTS thin films grown by means of PLD technique without resorting to any post sulfurization process. • Effect of thermal annealing treatments (in the 200–500 °C range) on the structural, morphological and optoelectronic properties of PLD-CZTS films. • Experimental determination of key optoelectronic parameters (i.e.; E{sub g}, VBM, ϕ, I{sub p}, and χ) enabling the reconstruction of energy band electronic structure of the PLD-CZTS films. • Investigation on the energy band alignments of the heterojunction interface formed between CZTS and both CdS and ZnS buffer layer materials. - Abstract: We report here on the use of pulsed KrF-laser deposition (PLD) technique for the growth of high-quality Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films onto Si, and glass substrates without resorting to any post sulfurization process. The PLD-CZTS films were deposited at room temperature (RT) and then subjected to post annealing at different temperatures ranging from 200 to 500 °C in Argon atmosphere. The X-ray diffraction and Raman spectroscopy confirmed that the PLD films crystallize in the characteristic kesterite CZTS structure regardless of their annealing temperature (T{sub a}), but their crystallinity is much improved for T{sub a} ≥ 400 °C. The PLD-CZTS films were found to exhibit a relatively dense morphology with a surface roughness (RMS) that increases with T{sub a} (from ∼14 nm at RT to 70 nm at T{sub a} = 500 °C with a value around 40 nm for T{sub a} = 300–400 °C). The optical bandgap of the PLD-CZTS films, was derived from UV–vis transmission spectra analysis, and found to decrease from 1.73 eV for non-annealed films to ∼1.58 eV for those annealed at T{sub a} = 300 °C. These band gap values are very close to the optimum value needed for an ideal solar cell absorber. In order to achieve a complete reconstruction of the one-dimensional energy band structure of these PLD-CZTS absorbers, we have combined both XPS and UPS

  17. Development of a selective thin film and of a hermetically sealed flat plate solar collector with gas filling

    Zernial, W.

    1982-12-01

    The industrial productibility of a selective absorbing thin film was investigated on the basis of reactive cathodic sputtering of Ni. On substrates of 1.8 sq m of Al, Cu, steel and stainless steel, solar absorption values up to 97% were achieved at emissivities of 5 to 10%. A prototype flat plate collector for high temperatures with two covers and hermetical sealing was developed. The technical data of the collector were measured, dependent on the selectivity of the absorber, gas fillings of dry air, argon or SF6 and the geometry and were compared with those of an evacuated flat plate collector. A hermetical sealed double flat plate collector for low temperatures was developed which has the advantage of lower no load temperatures and higher energy gain for heating swimming pool water compared with a conventional flat plate collector. The insolation values on collectors were measured and were used for a calculation of the energy gains of different collector types.

  18. Laser Process for Selective Emitter Silicon Solar Cells

    G. Poulain

    2012-01-01

    Full Text Available Selective emitter solar cells can provide a significant increase in conversion efficiency. However current approaches need many technological steps and alignment procedures. This paper reports on a preliminary attempt to reduce the number of processing steps and therefore the cost of selective emitter cells. In the developed procedure, a phosphorous glass covered with silicon nitride acts as the doping source. A laser is used to open locally the antireflection coating and at the same time achieve local phosphorus diffusion. In this process the standard chemical etching of the phosphorous glass is avoided. Sheet resistance variation from 100 Ω/sq to 40 Ω/sq is demonstrated with a nanosecond UV laser. Numerical simulation of the laser-matter interaction is discussed to understand the dopant diffusion efficiency. Preliminary solar cells results show a 0.5% improvement compared with a homogeneous emitter structure.

  19. Relationship between open-circuit voltage in Cu(In,Ga)Se2 solar cell and peak position of (220/204) preferred orientation near its absorber surface

    Chantana, J.; Minemoto, T.; Watanabe, T.; Teraji, S.; Kawamura, K.

    2013-01-01

    Cu(In,Ga)Se 2 (CIGS) absorbers with various Ga/III, Ga/(In+Ga), profiles are prepared by the so-called “multi-layer precursor method” using multi-layer co-evaporation of material sources. It is revealed that open-circuit voltage (V OC ) of CIGS solar cell is primarily dependent on averaged Ga/III near the surface of its absorber. This averaged Ga/III is well predicted by peak position of (220/204) preferred orientation of CIGS film near its surface investigated by glancing-incidence X-ray diffraction with 0.1° incident angle. Finally, the peak position of (220/204) preferred orientation is proposed as a measure of V OC before solar cell fabrication

  20. Preparation of CuGaSe2 absorber layers for thin film solar cells by annealing of efficiently electrodeposited Cu-Ga precursor layers from ionic liquids

    Steichen, M.; Larsen, J.; Guetay, L.; Siebentritt, S.; Dale, P.J.

    2011-01-01

    CuGaSe 2 absorber layers were prepared on molybdenum substrates by electrochemical codeposition of copper and gallium and subsequential annealing in selenium vapour. The electrodeposition was made from a deep eutectic based ionic liquid consisting of choline chloride/urea (Reline) with a plating efficiency of over 85%. The precursor film composition is controlled by the ratio of the copper to gallium fluxes under hydrodynamic conditions and by the applied deposition potential. X-ray diffraction reveals CuGa 2 alloying during the electrodeposition and CuGaSe 2 formation after annealing. Photoluminescence (PL) and photocurrent spectroscopy revealed the good opto-electronic properties of the CuGaSe 2 absorber films. The absorber layers have been converted to full devices with the best device achieving 4.0 % solar conversion efficiency.

  1. Influence of solar radiation absorbed by phytoplankton on the thermal structure and circulation of the tropical Atlantic Ocean

    Frouin, Robert; Ueyoshi, Kyozo; Kampel, Milton

    2007-09-01

    Numerical experiments conducted with an ocean general ocean circulation model reveal the potential influence of solar radiation absorbed by phytoplankton on the thermal structure and currents of the Tropical Atlantic Ocean. In the model, solar radiation penetration is parameterized explicitly as a function of chlorophyll-a concentration, the major variable affecting water turbidity in the open ocean. Two types of runs are performed, a clear water (control) run with a constant minimum chlorophyll-a concentration of 0.02 mgm -3, and a turbid water (chlorophyll) run with space- and time-varying chlorophyll-a concentration from satellite data. The difference between results from the two runs yields the biological effects. In the chlorophyll run, nutrients and biology production are implicitly taken into account, even though biogeochemical processes are not explicitly included, since phytoplankton distribution, prescribed from observations, is the result of those processes. Due to phytoplankton-radiation forcing, the surface temperature is higher by 1-2 K on average annually in the region of the North Equatorial current, the Northern part of the South Equatorial current, and the Caribbean system, and by 3-4 K in the region of the Guinea current. In this region, upwelling is reduced, and heat trapped in the surface layers by phytoplankton is not easily removed. The surface temperature is lower by 1 K in the Northern region of the Benguela current, due to increased upwelling. At depth, the equatorial Atlantic is generally cooler, as well as the eastern part of the tropical basin (excluding the region of the sub-tropical gyres). The North and South equatorial currents, as well as the Equatorial undercurrent, are enhanced by as much as 3-4 cms -1, and the circulation of the subtropical gyres is increased. Pole-ward heat transport is slightly reduced North of 35°N, suggesting that phytoplankton, by increasing the horizontal return flow in the subtropical region, may exert a

  2. Scientific basis for the selection of absorbent underpads that remain securely attached to underlying bed or chair.

    Edlich, Richard F; Winters, Kathryne L; Long, William B; Gubler, K Dean

    2006-01-01

    The occurrence of pressure ulcers in patients is very high in certain high-risk groups. These special high-risk groups include elderly patients, patients with spinal cord injuries, or any individual with an impaired ability to reposition. Prevention of pressure ulcers is by far the best treatment of this condition, warranting certain interventions and preventive measures. One major risk factor to be minimized is the exposure of skin to moisture. Underpads are often used to protect the skin of patients who are incontinent. These products effectively absorb moisture and present a quick-drying surface to the skin. The construction of an underpad should accomplish three goals. First, its backing should have a low coefficient of friction to prevent frictional skin injuries. Second, an inner absorbent core should rapidly contain moisture and disseminate it throughout the entire pad. Third, the core and coverstock should successfully work together to retain moisture and prevent wet-back or fluid return. The purpose of this study was to determine the performance of three commercially available underpads in reducing the development of pressure sores in patients at high risk. In this study we selected three underpads that could be securely attached to either the underlying bed or the chair. The three performance parameters examined were absorbent capacity, wetback prevention, and holding security of the underpads. Measurements of these performance parameters can be easily replicated in other laboratories. The results of these studies provide a scientific basis for selecting and purchasing an underpad to prevent pressure ulcers in patients. In this comprehensive evaluation, we assess an absorbent underpad with polyethylene flaps and two absorbent underpads with adhesive. The absorbent capacity results showed Tranquility SlimLine Peach Sheet to be the most absorbent. The wet-back results showed Tranquility SlimLine Peach Sheet to be the only underpad with no wet-back, with no

  3. Atlas of albedo and absorbed solar radiation derived from Nimbus 7 earth radiation budget data set, November 1985 to October 1987

    Smith, G. Louis; Rutan, David; Bess, T. Dale

    1992-01-01

    An atlas of monthly mean global contour maps of albedo and absorbed solar radiation is presented for 21 months from Nov. 1985 to Oct. 1987. These data were retrieved from measurements made by the shortwave wide-field-of-view radiometer of the Earth Radiation Budget (ERB) instrument aboard the Nimbus 7 spacecraft. Profiles of zonal mean albedos and absorbed solar radiation were tabulated. These geographical distributions are provided as a resource for researchers studying the radiation budget of the Earth. The El Nino/Southern Oscillation event of 1986-1987 is included in this data set. This atlas of albedo and absorbed solar radiation extends to 12 years the period covered by two similar atlases: NASA RP-1230 (Jul. 1975 - Oct. 1978) and NASA RP-1231 (Nov. 1978 - Oct. 1985). These three compilations complement the atlases of outgoing longwave radiation by Bess and Smith in NASA RP-1185, RP-1186, and RP-1261, which were also based on the Nimbus 6 and 7 ERB data.

  4. Spatial and temporal variations of albedo and absorbed solar radiation during 2009 - 2016 from IKOR-M satellite program

    Cherviakov, Maksim; Bogdanov, Mikhail; Spiryakhina, Anastasia; Shishkina, Elena; Surkova, Yana; Kulkova, Eugenia

    2017-04-01

    This report describes Earth's radiation budget IKOR-M satellite program which has been started in Russia. The first satellite "Meteor-M» No 1 of this project was put into orbit in September, 2009. The IKOR-M radiometer is a satellite instrument that measures reflected shortwave radiation (0.3-4.0 µm). It was created in Saratov State University and installed on Russian hydrometeorological satellites "Meteor-M" No 1 and No 2. Radiometer IKOR-M designed for satellite monitoring of the outgoing reflected short-wave radiation, which is one of the components of Earth's radiation budget. Such measurements can be used to derive Earth's surface albedo and absorbed solar radiation. This information also can be used in different models of long-term weather forecasts and in researches of climate change trends (Sklyarov et al., 2016). Satellite "Meteor-M" No 1 and No 2 are heliosynchronous that allows observing from North to South Poles. The basic products of data processing are given in the form of global maps of distribution outgoing short-wave radiation (OSR), albedo and absorbed solar radiation (ASR). Such maps were made for each month during observation period. The IKOR-M product archive is available online at all times. A searchable catalogue of data products is continually updated and users may search and download data products via the Earth radiation balance components research laboratory website (http://www.sgu.ru/structure/geographic/metclim/balans) as soon as they become available. Two series of measurements from two different IKOR-M are available. The first radiometer had worked from October, 2009 to August, 2014 and second - from August, 2014 to the present. Therefore, there is a period when both radiometers work at the same time. Top-of-atmosphere fluxes deduced from the "Meteor-M" No 1 measurements in August, 2014 show very good agreement with the fluxes determined from "Meteor-M" No 2 (Bogdanov et al., 2016). The effect of aging is investigated for first IKOR

  5. Parametric Study on the Thermal Performance and Optimal Design Elements of Solar Air Heater Enhanced with Jet Impingement on a Corrugated Absorber Plate

    Alsanossi M. Aboghrara

    2018-01-01

    Full Text Available Previous works revealed that cross-corrugated absorber plate design and jet impingement on a flat absorber plate resulted in a significant increase in the performance of a solar air heater (SAH. Involving these two designs into one continuous design to improve the SAH performance remains absent in the literature. This study aimed to evaluate the achieved enhancement on performance parameters of a SAH with jet impingement on a corrugated absorber plate. An energy balance model was developed to compare the performance parameters of the proposed SAH with the other two SAHs. At a clear sky day and a mass flow rate of 0.04 kg/s, the hourly results revealed that the max fluid outlet temperatures for the proposed SAH, jet-to-flat plate SAH, and cross-corrugated plate SAH are 321, 317, and 313 K, respectively; the max absorber plate temperatures are 323.5, 326.5, and 328 K, respectively; the maximum temperature differences between the absorber plate and fluid outlet are ~3, 9, and 15 K, respectively; the max efficiencies are 65.7, 64.8, and 60%, respectively. Statistical t-test results confirmed significant differences between the mean efficiency of the proposed SAH and SAH with jet-to-flat plate. Hence, the proposed design is considered superior in improving the performance parameters of SAH compared to other designs.

  6. A critical review of selective absorbers for radioactive and hazardous species

    Elder, G R; Simpson, K [Bradtec Ltd., Bristol (United Kingdom)

    1997-02-01

    Selective removal of radioactive and hazardous species has been a fertile research area for several years. However, for commercial application sorbers need to possess satisfactory properties beyond selectivity and these are reviewed. The benefits of selectivity itself need to be set against the limits for liquid discharges and categorization of solid wastes. Two examples are given to illustrate the aspects described. Many current and potential applications of selective adsorbers are to process streams which were not designed for waste management, but consideration of this at the planning stage as now occurs in the nuclear industry can lead to economic benefit. (author). 10 refs, 1 fig., 2 tabs.

  7. A critical review of selective absorbers for radioactive and hazardous species

    Elder, G.R.; Simpson, K.

    1997-01-01

    Selective removal of radioactive and hazardous species has been a fertile research area for several years. However, for commercial application sorbers need to possess satisfactory properties beyond selectivity and these are reviewed. The benefits of selectivity itself need to be set against the limits for liquid discharges and categorization of solid wastes. Two examples are given to illustrate the aspects described. Many current and potential applications of selective adsorbers are to process streams which were not designed for waste management, but consideration of this at the planning stage as now occurs in the nuclear industry can lead to economic benefit. (author). 10 refs, 1 fig., 2 tabs

  8. Correlation between the physical parameters of the i-nc-Si absorber layer grown by 27.12 MHz plasma with the nc-Si solar cell parameters

    Das, Debajyoti; Mondal, Praloy

    2017-09-01

    Growth of highly conducting nanocrystalline silicon (nc-Si) thin films of optimum crystalline volume fraction, involving dominant crystallographic preferred orientation with simultaneous low fraction of microstructures at a low substrate temperature and high growth rate, is a challenging task for its promising utilization in nc-Si solar cells. Utilizing enhanced electron density and superior ion flux densities of the high frequency (∼27.12 MHz) SiH4 plasma, improved nc-Si films have been produced by simple optimization of H2-dilution, controlling the ion damage and enhancing supply of atomic-hydrogen onto the growing surface. Single junction nc-Si p-i-n solar cells have been prepared with i-nc-Si absorber layer and optimized. The physical parameters of the absorber layer have been systematically correlated to variations of the solar cell parameters. The preferred alignment of crystallites, its contribution to the low recombination losses for conduction of charge carriers along the vertical direction, its spectroscopic correlation with the dominant growth of ultra-nanocrystalline silicon (unc-Si) component and corresponding longer wavelength absorption, especially in the neighborhood of i/n-interface region recognize scientific and technological key issues that pave the ground for imminent advancement of multi-junction silicon solar cells.

  9. Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

    Li, Xing; Xiao, Jingfeng; He, Binbin

    2018-04-01

    Amazon forests play an important role in the global carbon cycle and Earth’s climate. The vulnerability of Amazon forests to drought remains highly controversial. Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought. We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis. Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space. The decomposition of SIF to SIF yield (SIFyield) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis. We found that the drought significantly reduced SIFyield, the emitted SIF per photon absorbed. The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIFyield and precipitation. We further found that SIFyield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions. Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, and can improve our understanding of the responses of Amazon forests to drought.

  10. Solar Energy - An Option for Future Energy Production

    Glaser, Peter E.

    1972-01-01

    Discusses the exponential growth of energy consumption and future consequences. Possible methods of converting solar energy to power such as direct energy conversion, focusing collectors, selective rediation absorbers, ocean thermal gradient, and space solar power are considered. (DF)

  11. Radiator selection for Space Station Solar Dynamic Power Systems

    Fleming, Mike; Hoehn, Frank

    A study was conducted to define the best radiator for heat rejection of the Space Station Solar Dynamic Power System. Included in the study were radiators for both the Organic Rankine Cycle and Closed Brayton Cycle heat engines. A number of potential approaches were considered for the Organic Rankine Cycle and a constructable radiator was chosen. Detailed optimizations of this concept were conducted resulting in a baseline for inclusion into the ORC Preliminary Design. A number of approaches were also considered for the CBC radiator. For this application a deployed pumped liquid radiator was selected which was also refined resulting in a baseline for the CBC preliminary design. This paper reports the results and methodology of these studies and describes the preliminary designs of the Space Station Solar Dynamic Power System radiators for both of the candidate heat engine cycles.

  12. Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectric properties

    Katumba, G

    2009-08-01

    Full Text Available as shown in Fig. 1(d). An implicit equation for the Bruggeman effective dielectric function, Brε , can be obtained from equations (5) and (6), as [2]: ( ) ( ) ( ) 01 =−+ −−+−+ − BrBjBr BrB A BrAjBr BrA A L f L f εεε εε εεε εε (7... above becomes [2]: Proc. of SPIE Vol. 7410 74100G-3 ( ) ( ) ( ) 013 1 3 1 =−+ −−+−+ −∑ = BrBjBr BrB A BrAjBr BrA j A L f L f εεε εε εεε εε (8) Equation (8) is symmetric with respect to interchanged roles of material...

  13. Platinum containing amorphous hydrogenated carbon (a-C:H/Pt) thin films as selective solar absorbers

    Lan, Yung-Hsiang; Brahma, Sanjaya; Tzeng, Y.H.; Ting, Jyh-Ming

    2014-01-01

    We have investigated a double-cermet structured thin film in which an a-C:H thin film was used as an anti-reflective (AR) layer and two platinum-containing amorphous hydrogenated carbon (a-C:H/Pt) thin films were used as the double cermet layers. A reactive co-sputter deposition method was used to prepare both the anti-reflective and cermet layers. Effects of the target power and heat treatment were studied. The obtained films were characterized using X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy. The optical absorptance and emittance of the as deposited and annealed films were determined using UV–vis-NIR spectroscopy. We show that the optical absorptance of the resulting double-cermet structured thin film is as high as 96% and remains to be 91% after heat treatment at 400 °C, indicating the thermal stability of the film

  14. Distributions of 14 elements on 60 selected absorbers from two simulant solutions (acid-dissolved sludge and alkaline supernate) for Hanford HLW Tank 102-SY

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1993-10-01

    Sixty commercially available or experimental absorber materials were evaluated for partitioning high-level radioactive waste. These absorbers included cation and anion exchange resins, inorganic exchangers, composite absorbers, and a series of liquid extractants sorbed on porous support-beads. The distributions of 14 elements onto each absorber were measured from simulated solutions that represent acid-dissolved sludge and alkaline supernate solutions from Hanford high-level waste (HLW) Tank 102-SY. The selected elements, which represent fission products (Ce, Cs, Sr, Tc, and Y); actinides (U, Pu, and Am); and matrix elements (Cr, Co, Fe, Mn, Zn, and Zr), were traced by radionuclides and assayed by gamma spectrometry. Distribution coefficients for each of the 1680 element/absorber/solution combinations were measured for dynamic contact periods of 30 min, 2 h, and 6 h to provide sorption kinetics information for the specified elements from these complex media. More than 5000 measured distribution coefficients are tabulated

  15. THE EXTENDED HIGH A ( V ) QUASAR SURVEY: SEARCHING FOR DUSTY ABSORBERS TOWARD MID-INFRARED-SELECTED QUASARS

    Krogager, J.-K.; Noterdaeme, P. [Institut d’Astrophysique de Paris, CNRS-UPMC, UMR7095, 98bis bd Arago, F-75014 Paris (France); Fynbo, J. P. U.; Heintz, K. E.; Vestergaard, M. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Geier, S. [Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain); Ledoux, C. [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile); Møller, P. [European Southern Observatory, Karl-Schwarzschildstrasse 2, D-85748 Garching bei München (Germany); Venemans, B. P. [Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2016-11-20

    We present the results of a new spectroscopic survey for dusty intervening absorption systems, particularly damped Ly α absorbers (DLAs), toward reddened quasars. The candidate quasars are selected from mid-infrared photometry from the Wide-field Infrared Survey Explorer combined with optical and near-infrared photometry. Out of 1073 candidates, we secure low-resolution spectra for 108 using the Nordic Optical Telescope on La Palma, Spain. Based on the spectra, we are able to classify 100 of the 108 targets as quasars. A large fraction (50%) is observed to have broad absorption lines (BALs). Moreover, we find six quasars with strange breaks in their spectra, which are not consistent with regular dust reddening. Using template fitting, we infer the amount of reddening along each line of sight ranging from A ( V ) ≈ 0.1 to 1.2 mag (assuming a Small Magellanic Cloud extinction curve). In four cases, the reddening is consistent with dust exhibiting the 2175 Å feature caused by an intervening absorber, and for two of these, an Mg ii absorption system is observed at the best-fit absorption redshift. In the rest of the cases, the reddening is most likely intrinsic to the quasar. We observe no evidence for dusty DLAs in this survey. However, the large fraction of BAL quasars hampers the detection of absorption systems. Out of the 50 non-BAL quasars, only 28 have sufficiently high redshift to detect Ly α in absorption.

  16. Development of Novel Absorbents and Membranes by Radiation-Induced Grafting for Selective Purposes

    Hegazy, E A; Abdel-Rehim, H; Hegazy, D; Ali, A A; Kamal, H; Sayed, A [National Center for Radiation Research and Technology, Atomic Energy Egypt, P.O.Box 29, Nasr City, Cairo (Egypt)

    2012-09-15

    The direct radiation grafting technique was used to graft glycidyl methacrylate (GMA) monomer containing epoxy ring, onto polypropylene fibres. The ring opening of the epoxy ring in GMA by different amino groups was studied to introduce various chelating agents. Some properties of grafted fibres were studied and the possibility of its practical use for water treatment from iron and manganese metals was investigated. The radiation initiated grafting of acrylic acid (AAc) or acrylamide (AAm) monomers onto poly(vinyl alcohol) (PVA), a 2-acrylamide-2-methyl propane sulfonic acid (AMPS) polymer was studied. Cationic/anionic membranes were also prepared by radiation-induced grafting of styrene/methacrylic acid (Sty/MAA) binary monomers onto LDPE films. To impart reactive cationic/anionic characters in the grafted membranes, sulfonation and alkaline treatments for styrene and carboxylic acid groups, respectively, were carried out. The possibility of their applications in the selective removal of some heavy metals was studied. The prepared grafted materials had a great ability to recover the metal ions such as: Ni{sup 2+}, Co{sup 2+}, Cu{sup 2+}, Cd{sup 2+}, Mg{sup 2+}, Zn{sup 2+}, Mn{sup 2+} and Cr{sup 3+} from their solutions. It was found that AMPS content in the grafted copolymers is the main parameter for the selectivity of the copolymer towards metal ions. The higher the AMPS content the higher the selectivity towards Co and Ni ions. In case of LDPE-g-P(STY/MAA), the sulfonation and alkaline treatments are the most effective methods to influence metal absorption and swelling behaviour of the prepared membranes. Graft composition, dose and pH have also a great influence on the membrane characteristics and applicability in wastewater treatments from heavy and toxic metals. Results revealed that the prepared grafted materials with different functionalized groups are promising as ion selective membranes and could be used for wastewater treatment. (author)

  17. Multicriteria analysis in selecting the optimal variant of solar system

    Radziejowska Aleksandra

    2016-01-01

    Full Text Available Alternative energy sources are becoming more serious competition to traditional ways of generating energy. It becomes real integration of eco-energy with ecology, as well as the innovative technologies with low-energy construction. Apart from the cost an important issue are technical parameters of the equipment, durability, ease of installation, etc. The investor therefore is facing with the problem of decision-making to choose the best solution from the point of view of many criteria. In the article, the authors present the proposal to apply the methods of multi-criteria analysis to select the most beneficial variant of the solar system solutions. In this purpose will be use among other method: multivariate analysis of Saaty’s AHP, the taxonomic method of weighting factors and, belonging to a group of methods using outranking relations, the Promethee II method. Proposed comparative analysis can be used as a method for decision support during the selection of the most beneficial technological solution of solar installation and to evaluate operational efficiency existing buildings which will have implemented new systems.

  18. Performance Study of a Cylindrical Parabolic Concentrating Solar Water Heater with Nail Type Twisted Tape Inserts in the Copper Absorber Tube

    Amit K. Bhakta

    2018-01-01

    Full Text Available This paper reports the overall thermal performance of a cylindrical parabolic concentrating solar water heater (CPCSWH with inserting nail type twisted tape (NTT in the copper absorber tube for the nail twist pitch ratios, 4.787, 6.914 and 9.042, respectively. The experiments are conducted for a constant volumetric water flow rate and during the time period 9:00 a.m. to 15:00 p.m. The useful heat gain, hourly solar energy collected and hourly solar energy stored in this solar water heater were found to be higher for the nail twist pitch ratio 4.787. The above said parameters were found to be at a peak at noon and observed to follow the path of variation of solar intensity. At the start of the experiment, the value of charging efficiency was observed to be maximum, whereas the maximum values of instantaneous efficiency and overall thermal efficiency were observed at noon. The key finding is that the nail twist pitch ratio enhances the overall thermal performance of the CPCSWH.

  19. Deposition and characterization of spray pyrolysed p-type Cu2SnS3 thin film for potential absorber layer of solar cell

    Thiruvenkadam, S.; Sakthi, P.; Prabhakaran, S.; Chakravarty, Sujay; Ganesan, V.; Rajesh, A. Leo

    2018-06-01

    Thin film of ternary Cu2SnS3 (CTS), a potential absorber layer for solar cells was successfully deposited by chemical spray pyrolysis technique. The GIXRD pattern revealed that the film having tetragonal Cu2SnS3 phase with the preferential orientation along (112), (200), (220) and (312) plane and it is further confirmed using Raman spectroscopy by the existence of Raman peak at 320 cm-1. Atomic Force Microscopy (AFM) was used to estimate the surface roughness of 28.8 nm. The absorption coefficient was found to be greater than the order of 105 cm-1 and bandgap of 1.70 eV. Hall effect measurement indicates the p type nature of the film with a hole concentration of 1.03 × 1016cm-3 and a hall mobility of 404 cm2/V. The properties of CTS thin film confirmed suitable to be a potential absorber layer material for photovoltaic applications.

  20. Improving Efficiency of Evaporated Cu2ZnSnS4 Thin Film Solar Cells by a Thin Ag Intermediate Layer between Absorber and Back Contact

    Hongtao Cui

    2015-01-01

    Full Text Available A 20 nm Ag coating on Mo back contact was adopted to improve the back contact of evaporated Cu2ZnSnS4 (CZTS solar cells. The Ag layer helped reduce the thickness of MoS2 which improves fill factor (FF significantly; additionally, it reduced secondary phases ZnS and SnS2−x, which may help carrier transport; it was also involved in the doping of the absorber layer, which compensated the intrinsic p-type doping and therefore drags down the doping level. The doping involvement may enlarge the depletion region and improve lifetime of the absorber, which led to enhancing open circuit voltage (VOC, short circuit current density (JSC, and efficiency significantly. However, it degrades the crystallinity of the material slightly.

  1. Investigation of blister formation in sputtered Cu{sub 2}ZnSnS{sub 4} absorbers for thin film solar cells

    Bras, Patrice, E-mail: patrice.bras@angstrom.uu.se [Midsummer AB, Elektronikhöjden 6, SE-17543 Järfälla, Sweden and Solid State Electronics, Angström Laboratory, Uppsala University, Box 534, SE-75121 Uppsala (Sweden); Sterner, Jan [Midsummer AB, Elektronikhöjden 6, SE-17543 Järfälla (Sweden); Platzer-Björkman, Charlotte [Solid State Electronics, Angström Laboratory, Uppsala University, Box 534, SE-75121 Uppsala (Sweden)

    2015-11-15

    Blister formation in Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films sputtered from a quaternary compound target is investigated. While the thin film structure, composition, and substrate material are not correlated to the blister formation, a strong link between sputtering gas entrapment, in this case argon, and blistering effect is found. It is shown that argon is trapped in the film during sputtering and migrates to locally form blisters during the high temperature annealing. Blister formation in CZTS absorbers is detrimental for thin film solar cell fabrication causing partial peeling of the absorber layer and potential shunt paths in the complete device. Reduced sputtering gas entrapment, and blister formation, is seen for higher sputtering pressure, higher substrate temperature, and change of sputtering gas to larger atoms. This is all in accordance with previous publications on blister formation caused by sputtering gas entrapment in other materials.

  2. Synthesis and characterizations of Cu2ZnSnS4 nanoparticles/carbon nanotube composite as an efficient absorber material for solar cell application

    Das, S.; Sa, K.; Alam, I.; Mahakul, P. C.; Raiguru, J.; Subramanyam, B. V. R. S.; Mahanandia, P.

    2018-05-01

    In this energy crisis era, the urgent calls for clean energy converter realizes the importance of photovoltaic device, which offers the highest probability of delivering a sustainable way of harvesting solar energy. The active absorber layer has its significance towards the performance of photovoltaic device by absorbing solar light and creating electron-hole pair inside layer. Being a direct p-type semiconductor, Cu2ZnSnS4 generally referred as CZTS has emerged as potential absorber towards photovoltaics application in recent decades as it offers the advantage of tunable band gap near optimal region ˜1.45-1.65 eV favorably match the solar spectrum and a high absorption coefficient ˜104 cm-1. The further improvement in the performance of CZTS based photovoltaics has involved the use of carbon nanotubes (CNTs). Semiconductors hybridized with carbonaceous materials (CNTs) have been the center of attraction in the scientific community with beneficial contribution in enhancing optoelectronic properties. The incorporation of CNTs shows effectiveness in charge carrier transfer pathways which ultimately could enhance the photo conversion efficiency (PCE) of photovoltaic device cell (PVC). Here, a facile hydrothermal one-pot synthesis of CZTS nanoparticles and MWCNTs composite towards photovoltaics application is reported. The phase and structural analysis of CZTS nanoparticles as well as CZTS/MWCNTs composite is done by XRD. From FERSEM and TEM (LRTEM & HRTEM) analysis the CZTS nanoparticles decorated over the surface of MWCNTs is confirmed. The optical band gap of CZTS/MWCNTs composite is estimated to be 1.62 eV from UV-Visible spectra.

  3. Thermal Performance of Solar Air Heater Having Absorber Plate with V-Down Discrete Rib Roughness for Space-Heating Applications

    Rajendra Karwa

    2013-01-01

    Full Text Available The paper presents results of thermal performance analysis of a solar air heater with v-down discrete rib roughness on the air flow side of the absorber plate, which supplies heated air for space heating applications. The air heater operates in a closed loop mode with inlet air at a fixed temperature of 295 K from the conditional space. The ambient temperature varied from 278 K to 288 K corresponding to the winter season of Western Rajasthan, India. The results of the analysis are presented in the form of performance plots, which can be utilized by a designer for calculating desired air flow rate at different ambient temperature and solar insolation values.

  4. Selective coating for solar panels. [using black chrome and black nickel

    Mcdonald, G. E. (Inventor)

    1977-01-01

    The energy absorbing properties of solar heating panels are improved by depositing a black chrome coating of controlled thickness on a specially prepared surface of a metal substrate. The surface is prepared by depositing a dull nickel on the substrate, and the black chrome is plated on this low emittance surface to a thickness between 0.5 micron and 2.5 microns.

  5. Modeling and Simulation of Turbulent Flows through a Solar Air Heater Having Square-Sectioned Transverse Rib Roughness on the Absorber Plate

    Anil Singh Yadav

    2013-01-01

    Full Text Available Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. Use of artificial roughness on a surface is an effective technique to enhance the rate of heat transfer. A CFD-based investigation of turbulent flow through a solar air heater roughened with square-sectioned transverse rib roughness has been performed. Three different values of rib-pitch (P and rib-height (e have been taken such that the relative roughness pitch (P/e=14.29 remains constant. The relative roughness height, e/D, varies from 0.021 to 0.06, and the Reynolds number, Re, varies from 3800 to 18,000. The results predicted by CFD show that the average heat transfer, average flow friction, and thermohydraulic performance parameter are strongly dependent on the relative roughness height. A maximum value of thermohydraulic performance parameter has been found to be 1.8 for the range of parameters investigated. Comparisons with previously published work have been performed and found to be in excellent agreement.

  6. Modeling and simulation of turbulent flows through a solar air heater having square-sectioned transverse rib roughness on the absorber plate.

    Yadav, Anil Singh; Bhagoria, J L

    2013-01-01

    Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. Use of artificial roughness on a surface is an effective technique to enhance the rate of heat transfer. A CFD-based investigation of turbulent flow through a solar air heater roughened with square-sectioned transverse rib roughness has been performed. Three different values of rib-pitch (P) and rib-height (e) have been taken such that the relative roughness pitch (P/e = 14.29) remains constant. The relative roughness height, e/D, varies from 0.021 to 0.06, and the Reynolds number, Re, varies from 3800 to 18,000. The results predicted by CFD show that the average heat transfer, average flow friction, and thermohydraulic performance parameter are strongly dependent on the relative roughness height. A maximum value of thermohydraulic performance parameter has been found to be 1.8 for the range of parameters investigated. Comparisons with previously published work have been performed and found to be in excellent agreement.

  7. Charge transport in quantum dot organic solar cells with Si quantum dots sandwiched between poly(3-hexylthiophene) (P3HT) absorber and bathocuproine (BCP) transport layers

    Verma, Upendra Kumar; Kumar, Brijesh

    2017-10-01

    We have modeled a multilayer quantum dot organic solar cell that explores the current-voltage characteristic of the solar cell whose characteristics can be tuned by varying the fabrication parameters of the quantum dots (QDs). The modeled device consists of a hole transport layer (HTL) which doubles up as photon absorbing layer, several quantum dot layers, and an electron transport layer (ETL). The conduction of charge carriers in HTL and ETL has been modeled by the drift-diffusion transport mechanism. The conduction and recombination in the quantum dot layers are described by a system of coupled rate equations incorporating tunneling and bimolecular recombination. Analysis of QD-solar cells shows improved device performance compared to the similar bilayer and trilayer device structures without QDs. Keeping other design parameters constant, solar cell characteristics can be controlled by the quantum dot layers. Bimolecular recombination coefficient of quantum dots is a prime factor which controls the open circuit voltage (VOC) without any significant reduction in short circuit current (JSC).

  8. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    Takeda, Yasuhiko; Sugimoto, Noriaki; Ichiki, Akihisa; Kusano, Yuya; Motohiro, Tomoyoshi

    2015-01-01

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs

  9. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    Takeda, Yasuhiko, E-mail: takeda@mosk.tytlabs.co.jp; Sugimoto, Noriaki [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Ichiki, Akihisa [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Kusano, Yuya [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Toyota Motor Corp., 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Motohiro, Tomoyoshi [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

    2015-09-28

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs.

  10. Experimental Analysis of the Thermo-Hydraulic Performance on a Cylindrical Parabolic Concentrating Solar Water Heater with Twisted Tape Inserts in an Absorber Tube

    Kumar, Birendra; Nayak, Rajen Kumar; Singh, S. N.

    2018-05-01

    A twisted tape inserted in an absorber tube may be an excellent option to enhance the performance of a cylindrical parabolic concentrating solar collector (CPC). The present work is an experimental study of the flow and heat transfer with and without twisted tape inserts in the absorber tube of a CPC. Results are presented for mass flow rates of water, ṁ=0.0198-0.0525 kg/s, twist ratio, y=5-10 and Reynolds number, Re=2577.46-6785.55. In the present study, we found that the outlet water temperature, collector efficiency and Nusselt number (Nu) are higher in the twisted tapes as compared to those without the twisted tape inserts in the absorber tube of the CPC. For fixed mass flow rate of water ṁ, the To and η increased with the decrease in twist ratio, y, and is higher in lower twist ratio, y=5, of the twisted tapes. The whole experiment was performed at the Indian Institute of Technology (ISM) in Dhanbad, India during the months of March-April 2017. Based on the experimental data, the correlations for the Nu and friction factor were also developed.

  11. Optimum selection of solar collectors for a solar-driven ejector air conditioning system by experimental and simulation study

    Zhang Wei; Ma Xiaoli; Omer, S.A.; Riffat, S.B.

    2012-01-01

    Highlights: ► Three solar collectors have been compared to drive ejector air conditioning system. ► A simulation program was constructed to study the effect parameters. ► The outdoor test were conducted to validate the solar collector modeling. ► Simulation program was found to predict solar collector performance accurately. ► The optimal design of solar collector system was carried out. - Abstract: In this paper, three different solar collectors are selected to drive the solar ejector air conditioning system for Mediterranean climate. The performance of the three selected solar collector are evaluated by computer simulation and lab test. Computer model is incorporated with a set of heat balance equations being able to analyze heat transfer process occurring in separate regions of the collector. It is found simulation and test has a good agreement. By the analysis of the computer simulation and test result, the solar ejector cooling system using the evacuated tube collector with selective surface and high performance heat pipe can be most economical when operated at the optimum generating temperature of the ejector cooling machine.

  12. CuInGaAlSe2 Solar Absorbers On Flexible High-Temperature Substrates, Phase I

    National Aeronautics and Space Administration — ITN Energy Systems (ITN) proposes to take the next step in spacecraft solar array development, building upon previous development and new findings to make the...

  13. CuInGaAlSe2 Solar Absorbers On Flexible High-Temperature Substrates, Phase II

    National Aeronautics and Space Administration — ITN Energy Systems (ITN) proposes to take the next step in spacecraft solar array development, building upon previous development and new findings to make the...

  14. The use of solar cells for continuous recording of absorbed dose in the product during radiation sterilization

    Moehlmann, J.H.F.

    1981-01-01

    As a result of the rapidly developing space programme, reliable solar panels were needed as an energy source for space capsules. It was found that when a space capsule passed through the Van Allen Belt, the solar panels aged owing to the radiation, and the energy output declined. The United States National Aeronautics and Space Administration investigated the pre-irradiation of solar panels and found that they withstood high doses, such as 20 Mrad, the panels having aged and the energy output having become lower but steady. The response of the solar cells to high levels of radiation caused Gammaster to attempt to use this effect to serve as a check on the operating status of its large 60 Co gamma irradiation facility. During γ-irradiation a potential is generated in a p-n silicon solar cell which can be made to drive ancillary equipment. For example, the current from the solar cell can be fed to a pen recorder to assist in process control. The pen recorder can, for example, also act as an automatic logbook by recording the irradiation times. The sensitivity of a cell is such that changes in absorption between homogeneously and inhomogeneously filled containers are clearly shown on the recorder sheets. All source movements are visible, and the timer setting and the number of containers treated, etc. can be monitored. Such a system provides a reliable additional process control at low cost and requests little maintenance. (author)

  15. Wavelength-Selective Solar Photovoltaic Systems: Powering Greenhouses for Plant Growth at the Food-Energy-Water Nexus

    Loik, Michael E.; Carter, Sue A.; Alers, Glenn; Wade, Catherine E.; Shugar, David; Corrado, Carley; Jokerst, Devin; Kitayama, Carol

    2017-10-01

    Global renewable electricity generation capacity has rapidly increased in the past decade. Increasing the sustainability of electricity generation and the market share of solar photovoltaics (PV) will require continued cost reductions or higher efficiencies. Wavelength-Selective Photovoltaic Systems (WSPVs) combine luminescent solar cell technology with conventional silicon-based PV, thereby increasing efficiency and lowering the cost of electricity generation. WSPVs absorb some of the blue and green wavelengths of the solar spectrum but transmit the remaining wavelengths that can be utilized by photosynthesis for plants growing below. WSPVs are ideal for integrating electricity generation with glasshouse production, but it is not clear how they may affect plant development and physiological processes. The effects of tomato photosynthesis under WSPVs showed a small decrease in water use, whereas there were minimal effects on the number and fresh weight of fruit for a number of commercial species. Although more research is required on the impacts of WSPVs, they are a promising technology for greater integration of distributed electricity generation with food production operations, for reducing water loss in crops grown in controlled environments, as building-integrated solar facilities, or as alternatives to high-impact PV for energy generation over agricultural or natural ecosystems.

  16. Epidermal UV-A absorbance and whole-leaf flavonoid composition in pea respond more to solar blue light than to solar UV radiation.

    Siipola, Sari M; Kotilainen, Titta; Sipari, Nina; Morales, Luis O; Lindfors, Anders V; Robson, T Matthew; Aphalo, Pedro J

    2015-05-01

    Plants synthesize phenolic compounds in response to certain environmental signals or stresses. One large group of phenolics, flavonoids, is considered particularly responsive to ultraviolet (UV) radiation. However, here we demonstrate that solar blue light stimulates flavonoid biosynthesis in the absence of UV-A and UV-B radiation. We grew pea plants (Pisum sativum cv. Meteor) outdoors, in Finland during the summer, under five types of filters differing in their spectral transmittance. These filters were used to (1) attenuate UV-B; (2) attenuate UV-B and UV-A radiation signals that extend into the visible region of the solar spectrum. Furthermore, solar blue light instead of solar UV-B radiation can be the main regulator of phenolic compound accumulation in plants that germinate and develop outdoors. © 2014 John Wiley & Sons Ltd.

  17. Shock absorber

    Housman, J.J.

    1978-01-01

    A shock absorber is described for use in a hostile environment at the end of a blind passage for absorbing impact loads. The shock absorber includes at least one element which occupies the passage and which is comprised of a porous brittle material which is substantially non-degradable in the hostile environment. A void volume is provided in the element to enable the element to absorb a predetermined level of energy upon being crushed due to impact loading

  18. Performance evaluation of a natural-convection solar air-heater with a rectangular-finned absorber plate

    Fakoor Pakdaman, M.; Lashkari, A.; Basirat Tabrizi, H.; Hosseini, R.

    2011-01-01

    This paper deals with an experimental investigation to evaluate different thermal characteristics of a natural-convection flat-plate solar air-heater with longitudinal rectangular fins array. Having determined the thermal performance of the system a Nusselt number correlation is presented for such finned duct devices. In the presented empirical model which may have industrial applications, solar radiation and ambient temperature have been considered as independent parameters. Other characteristics of the system such as different dimensionless variables, plates and outflow temperatures, efficiency, and mass flow rate have been empirically modeled based on these variables. The particular difference in this study in comparison with the other similar studies is the presentation of an empirical model for rectangular-finned solar air-heaters. This model proposes design concepts and rules of thumb, and demonstrates the calculations of the design parameters. Based on the order of magnitude analysis, solar radiation has been found to be the main parameter which characterizes the thermal behavior of the system. Besides, exergy analysis has been carried out, and optimum conditions in which the system has the highest performance have been determined.

  19. Distribution of absorbed heat in luminescent solar concentrator lightguides and effect of temperatures of mounted photovoltaic cells

    Rajkumar, V.A.; Weijers, C.; Debije, M.G.

    2015-01-01

    Polymer plates containing fluorescent dyes with photovoltaic cells attached to one or more edges have the potential to be used for solar light collection in the built environment. The heating of the polymer plates and the resulting effects this may have on the operating temperatures of the attached

  20. High Photon-to-Current Conversion in Solar Cells Based on Light-Absorbing Silver Bismuth Iodide.

    Zhu, Huimin; Pan, Mingao; Johansson, Malin B; Johansson, Erik M J

    2017-06-22

    Here, a lead-free silver bismuth iodide (AgI/BiI 3 ) with a crystal structure with space group R3‾ m is investigated for use in solar cells. Devices based on the silver bismuth iodide deposited from solution on top of TiO 2 and the conducting polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) as a hole-transport layer are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2 %, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700 nm, and the maximum external quantum efficiency is around 45 %. The results are compared to solar cells based on the previously reported material AgBi 2 I 7 , and we observe a clearly higher performance for the devices with the new silver and bismuth iodides composition and different crystal structure. The X-ray diffraction spectrum of the most efficient silver bismuth iodide material shows a hexagonal crystal structure with space group R3‾ m, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62 eV and a direct band gap energy of 1.85 eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  1. The effect of Arctic sea-ice extent on the absorbed (net solar flux at the surface, based on ISCCP-D2 cloud data for 1983–2007

    C. Matsoukas

    2010-01-01

    Full Text Available We estimate the effect of the Arctic sea ice on the absorbed (net solar flux using a radiative transfer model. Ice and cloud input data to the model come from satellite observations, processed by the International Satellite Cloud Climatology Project (ISCCP and span the period July 1983–June 2007. The sea-ice effect on the solar radiation fluctuates seasonally with the solar flux and decreases interannually in synchronisation with the decreasing sea-ice extent. A disappearance of the Arctic ice cap during the sunlit period of the year would radically reduce the local albedo and cause an annually averaged 19.7 W m−2 increase in absorbed solar flux at the Arctic Ocean surface, or equivalently an annually averaged 0.55 W m−2 increase on the planetary scale. In the clear-sky scenario these numbers increase to 34.9 and 0.97 W m−2, respectively. A meltdown only in September, with all other months unaffected, increases the Arctic annually averaged solar absorption by 0.32 W m−2. We examined the net solar flux trends for the Arctic Ocean and found that the areas absorbing the solar flux more rapidly are the North Chukchi and Kara Seas, Baffin and Hudson Bays, and Davis Strait. The sensitivity of the Arctic absorbed solar flux on sea-ice extent and cloud amount was assessed. Although sea ice and cloud affect jointly the solar flux, we found little evidence of strong non-linearities.

  2. Spray-deposited CuIn{sub 1-x}Ga{sub x}Se{sub 2} solar cell absorbers: Influence of spray deposition parameters and crystallization promoters

    Carrete, Alex; Placidi, Marcel; Shavel, Alexey [Catalonia Institute for Energy Research - IREC, Sant Adria del Besos, Barcelona (Spain); Perez-Rodriguez, Alejandro [Catalonia Institute for Energy Research - IREC, Sant Adria del Besos, Barcelona (Spain); IN2UB, Departament d' Electronica, Universitat de Barcelona (Spain); Cabot, Andreu [Catalonia Institute for Energy Research - IREC, Sant Adria del Besos, Barcelona (Spain); Institucio Catalana de Recerca i Estudis Avancats - ICREA, Barcelona (Spain)

    2015-01-01

    To produce smooth, crack-free, and highly crystalline absorber layers are the main challenges in the fabrication of thin film solar cells using nanoparticle-based solution-processing technologies. In this work, we report on the optimization of the spray deposition parameters to produce highly homogeneous CuIn{sub 1-x}Ga{sub x}S{sub 2} thin films with controlled thickness using nanoparticle-based inks. We further explore the use of inorganic ligand exchange strategies to introduce metal ions able to promote crystallization during the selenization of the layers, removing structural defects and grain boundaries that potentially act as recombination centers. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    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.

  4. Simplified Perovskite Solar Cell with 4.1% Efficiency Employing Inorganic CsPbBr3 as Light Absorber.

    Duan, Jialong; Zhao, Yuanyuan; He, Benlin; Tang, Qunwei

    2018-04-17

    Perovskite solar cells with cost-effectiveness, high power conversion efficiency, and improved stability are promising solutions to the energy crisis and environmental pollution. However, a wide-bandgap inorganic-semiconductor electron-transporting layer such as TiO 2 can harvest ultraviolet light to photodegrade perovskite halides, and the high cost of a state-of-the-art hole-transporting layer is an economic burden for commercialization. Here, the building of a simplified cesium lead bromide (CsPbBr 3 ) perovskite solar cell with fluorine-doped tin oxide (FTO)/CsPbBr 3 /carbon architecture by a multistep solution-processed deposition technology is demonstrated, achieving an efficiency as high as 4.1% and improved stability upon interfacial modification by graphene quantum dots and CsPbBrI 2 quantum dots. This work provides new opportunities of building next-generation solar cells with significantly simplified processes and reduced production costs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Mechanical properties of hybrid organic-inorganic CH3NH3BX3 (B = Sn, Pb; X = Br, I perovskites for solar cell absorbers

    Jing Feng

    2014-08-01

    Full Text Available The crystal structures, elastic and anisotropic properties of CH3NH3BX3 (B = Sn, Pb; X = Br, I compounds as solar cell absorber layers are investigated by the first-principles calculations. The type and strength of chemical bond B-X are found to determine the elastic properties. B-X bonds and the organic cations are therefore crucial to the functionalities of such absorbers. The bulk, shear, Young's modulus ranges from 12 to 30 GPa, 3 to 12 GPa, and 15 to 37 GPa, respectively. Moreover, the interaction among organic and inorganic ions would have negligible effect for elastic properties. The B/G and Poisson's ratio show it would have a good ductile ability for extensive deformation as a flexible/stretchable layer on the polymer substrate. The main reason is attributed to the low shear modulus of such perovskites. The anisotropic indices AU, AB AG, A1, A2, and A3 show ABX3 perovskite have very strong anisotropy derived from the elastic constants, chemical bonds, and symmetry.

  6. COMPORTAMIENTO DE LA TEMPERATURA DEL FLUJO DE AIRE EN UN ABSORBEDOR SOLAR BEHAVIOR OF THE TEMPERATURE OF THE FLOW OF AIR IN A SOLAR ABSORBER

    GERARDO C CIFUENTES

    2009-12-01

    Full Text Available El presente trabajo evalúa el comportamiento de la temperatura del flujo de aire en un colector solar de lecho de rocas, mediante un modelo matemático que simula las temperaturas del flujo de aire a la entrada y salida del colector. El modelo relaciona la geometría, la radiación incidente en el colector y las constantes propias del colector determinadas experimentalmente. Para el análisis se realizaron tres pruebas en las que se midieron las temperaturas del ambiente, de entrada y salida en el colector y la radiación solar incidente.The present work evaluates the behavior of the temperature of the flow of air in a solar collector of channel of rocks, by means of a mathematical model that simulates the temperatures from the flow of air to the entrance and exit of the collector. The pattern relates the geometry, the incident radiation in the collector and the constants own collector determined experimentally. For the analysis they were carried out three tests in those that the temperatures of the atmosphere were measured, of entrance and exit in the collector and the solar incident radiation.

  7. The formation of CuInSe{sub 2}-based thin-film solar cell absorbers from alternative low-cost precursors

    Jost, S.

    2008-01-18

    This work deals with real-time investigations concerning the crystallisation process of CuInSe{sub 2}-based thin-film solar cell absorbers while annealing differently produced and composed ''low-cost'' precursors. Various types of precursors have been investigated concerning their crystallisation behaviour. Three groups of experiments have been performed: (i) Investigations concerning the crystallisation process of the quaternary chalcopyrite Cu(In,Al)Se{sub 2} and Cu(In,Al)S{sub 2}, (ii) investigations concerning the formation process of the compound semiconductor CuInSe{sub 2} from electroplated precursors, and (iii) investigations concerning the crystallisation of Cu(In,Ga)Se{sub 2} using precursors with thermally evaporated indium. A specific sample surrounding has been constructed, which enables to perform time-resolved angle-dispersive X-ray powder diffraction experiments during the annealing process of precursor samples. A thorough analysis of subsequently recorded diffraction patterns using the Rietveld method provides a detailed knowledge about the semiconductor crystallisation process while annealing. Based on these fundamental investigations, conclusions have been drawn concerning an adaptation of the precursor deposition process in order to optimise the final solar cell results. The investigations have shown, that one class of electroplated precursors shows a crystallisation behaviour identical to the one known for vacuum-deposited precursors. The investigations concerning the crystallisation process of the quaternary chalcopyrite Cu(In,Al)Se{sub 2} revealed, that the chalcopyrite forms from the ternary selenide (Al,In){sub 2}Se{sub 3} and Cu{sub 2}Se at elevated process temperatures. This result is used to explain the separation of the absorber layer into an aluminum-rich and an indium-rich chalcopyrite phase, which has been observed at processed Cu(In,Al)Se{sub 2} absorbers from several research groups. In addition, differences

  8. Potassium doped methylammonium lead iodide (MAPbI3) thin films as a potential absorber for perovskite solar cells; structural, morphological, electronic and optoelectric properties

    Muzammal uz Zaman, Muhammad; Imran, Muhammad; Saleem, Abida; Kamboh, Afzal Hussain; Arshad, Muhammad; Khan, Nawazish Ali; Akhter, Parvez

    2017-10-01

    In this article, we have demonstrated the doping of K in the light absorbing CH3NH3PbI3 perovskite i.e. (M = CH3, A = NH3; x = 0-1). One of the major merits of methylammonium lead iodide (CH3NH3PbI3) perovskites is that they act as efficient absorbing material of light in photovoltaic cell imparting long carrier lifetime and optimum band gap. The structural, morphological, electronic and optoelectric properties of potassium (K) doped light absorber methylammonium lead iodide (CH3NH3PbI3) perovskites are reported here i.e. Kx(MA)1-xPbI3 (M = CH3, A =NH3; x = 0-1). The thin films of perovskites (x = 0-1) were deposited by spin coating on cleaned FTO substrates and characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), current-voltage (IV), X-ray photoelectron spectroscopy (XPS) and Diffused reflectance spectroscopy (DRS) analysis. The organic constituents i.e. MA = CH3NH3, in perovskites solar cells induce instability even at the room temperature. To overcome such instabilities we have replaced the organic constituents by K because both of them have electropositive nature. Potassium successfully replaces the CH3NH3. Initially, this compound grows in a tetragonal crystal structure, however, beyond 30% doping of potassium orthorhombic distortions are induced in the parent tetragonal unit cell. Such phase transformation is microscopically visible in the electron micrographs of doped samples; cubic grains for MAPbI3 begin to transform into strip like structures in K-doped samples. The resistance of the samples is decreased for partial K-doping, which we suggested to be arising due to the electropositive nature of K. It is observed that the binding energy difference between Pb4f and I3d core levels are very similar in all the investigated systems and show formal oxidation states. Also, the partially doped samples showed increased absorption and bandgaps around 1.5 eV which is an optimum value for solar absorption.

  9. Formation of a ZnS/Zn(S,O) bilayer buffer on CuInS2 thin film solar cell absorbers by chemical bath deposition

    Bär, M.; Ennaoui, A.; Klaer, J.; Kropp, T.; Sáez-Araoz, R.; Allsop, N.; Lauermann, I.; Schock, H.-W.; Lux-Steiner, M. C.

    2006-06-01

    The application of Zn compounds as buffer layers was recently extended to wide-gap CuInS2 (CIS) based thin film solar cells. Using an alternative chemical deposition route for the buffer preparation aiming at the deposition of a single-layer, nominal ZnS buffer without the need for any toxic reactants such as hydrazine has helped us to achieve a similar efficiency as respective CdS-buffered reference devices. In order to shed light on the differences of other Zn-compound buffers deposited in conventional chemical baths [chemical bath deposition (CBD)] compared to the buffer layers deposited by this alternative CBD process, the composition of the deposited buffers was investigated by x-ray excited Auger electron and x-ray photoelectron spectroscopy to potentially clarify their superiority in terms of device performance. We have found that in the early stages of this alternative CBD process a thin ZnS layer is formed on the CIS, whereas in the second half of the CBD the growth rate is greatly increased and Zn(S,O) with a ZnS/(ZnS+ZnO) ratio of ~80% is deposited. Thus, a ZnS/Zn(S,O) bilayer buffer is deposited on the CIS thin film solar cell absorbers by the alternative chemical deposition route used in this investigation. No major changes of these findings after a postannealing of the buffer/CIS sample series and recharacterization could be identified.

  10. Black silicon laser-doped selective emitter solar cell with 18.1% efficiency

    Davidsen, Rasmus Schmidt; Li, Hongzhao; To, Alexander

    2016-01-01

    We report fabrication of nanostructured, laser-doped selective emitter (LDSE) silicon solar cells with power conversion efficiency of 18.1% and a fill factor (FF) of 80.1%. The nanostructured solar cells were realized through a single step, mask-less, scalable reactive ion etch (RIE) texturing......-texturing as well as the LDSE process, we consider this specific combination a promising candidate for a cost-efficient process for future Si solar cells....

  11. Extracting Information about the Electronic Quality of Organic Solar-Cell Absorbers from Fill Factor and Thickness

    Kaienburg, Pascal; Rau, Uwe; Kirchartz, Thomas

    2016-08-01

    Understanding the fill factor in organic solar cells remains challenging due to its complex dependence on a multitude of parameters. By means of drift-diffusion simulations, we thoroughly analyze the fill factor of such low-mobility systems and demonstrate its dependence on a collection coefficient defined in this work. We systematically discuss the effect of different recombination mechanisms, space-charge regions, and contact properties. Based on these findings, we are able to interpret the thickness dependence of the fill factor for different experimental studies from the literature. The presented model provides a facile method to extract the photoactive layer's electronic quality which is of particular importance for the fill factor. We illustrate that over the past 15 years, the electronic quality has not been continuously improved, although organic solar-cell efficiencies increased steadily over the same period of time. Only recent reports show the synthesis of polymers for semiconducting films of high electronic quality that are able to produce new efficiency records.

  12. Solar pond-based rural development programme for selected coastal regions - A concept

    Gopinathan, C.K.

    is expected to aid speedy development of selected coastal areas. The programme involves design and construction of a solar pond in which brine in the lower layer is heated to 85 degrees C by solar radiation and is used as the heat source for a closed cycle...

  13. No-contact method of determining average working-surface temperature of plate-type radiation-absorbing thermal exchange panels of flat solar collectors for heating heat-transfer fluid

    Avezova, N.R.; Avezov, R.R.

    2015-01-01

    A brand new no-contact method of determining the average working-surface temperature of plate-type radiation-absorbing thermal exchange panels (RATEPs) of flat solar collectors (FSCs) for heating a heat-transfer fluid (HTF) is suggested on the basis of the results of thermal tests in full-scale quasistationary conditions. (authors)

  14. Sulfurization of sputtered Ag–In precursors for AgInS{sub 2} solar cell absorber layers

    Anantha Sunil, M. [Energy and Health Monitoring Instrumentation Laboratory, Department of Instrumentation & Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Thota, Narayana [Advanced Materials Research Laboratory, Department of Physics, Yogi Vemana University, Kadapa 516003 (India); Deepa, K.G. [Energy and Health Monitoring Instrumentation Laboratory, Department of Instrumentation & Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Jampana, Nagaraju, E-mail: solarjnr@gmail.com [Energy and Health Monitoring Instrumentation Laboratory, Department of Instrumentation & Applied Physics, Indian Institute of Science, Bangalore 560012 (India)

    2015-11-30

    Silver indium sulfide (AgInS{sub 2}) thin films are deposited by sequential sputtering of metallic precursor [Ag/In] followed by sulfurization. Effect of substrate temperature (T{sub sub}) during sulfurization process on the film growth is studied by varying the substrate temperature from 350 to 500 °C. Films prepared above 350 °C showed a mixture of orthorhombic and tetragonal phases of AgInS{sub 2} with tetragonal phase being dominant. Better crystalline, nearly stoichiometric and p-type films are obtained at a substrate temperature of 500 °C. The characteristic A{sub 1} mode of AgInS{sub 2} chalcopyrite structure is observed in the Raman spectra at 274 cm{sup −1} for the films prepared above 350 °C. The grain size of the film increases from 489 to 895 nm with the increase in substrate temperature. The binding energies of the constituent elements are determined using XPS. The band gap of AgInS{sub 2} films is in the range of 1.64–1.92 eV and the absorption coefficient is found to be > 10{sup 4} cm{sup −1}. Preliminary studies on the AgInS{sub 2}/ZnS solar cell showed an efficiency of 0.3%. - Highlights: • AgInS{sub 2} films are grown by sulfurization of sputtered metal precursors. • Effect of substrate temperature on the growth of AgInS{sub 2} films is studied. • Films sulfurized at 500 °C have the best structural and opto-electrical properties. • AgInS{sub 2}/ZnS solar cell has been fabricated with an efficiency of ~ 0.3%.

  15. Modulated charge injection in p-type dye-sensitized solar cells using fluorene-based light absorbers.

    Liu, Zonghao; Xiong, Dehua; Xu, Xiaobao; Arooj, Qudsia; Wang, Huan; Yin, Liyuan; Li, Wenhui; Wu, Huaizhi; Zhao, Zhixin; Chen, Wei; Wang, Mingkui; Wang, Feng; Cheng, Yi-Bing; He, Hongshan

    2014-03-12

    In this study, new pull-push arylamine-fluorene based organic dyes zzx-op1, zzx-op2, and zzx-op3 have been designed and synthesized for p-type dye-sensitized solar cells (p-DSCs). In zzx-op1, a di(p-carboxyphenyl)amine (DCPA) was used as an electron donor, a perylenemonoimide (PMID) as an electron acceptor, and a fluorene (FLU) unit with two aliphatic hexyl chains as a π-conjugated linker. In zzx-op2 and zzx-op3, a 3,4-ethylenedioxythiophene (EDOT) and a thiophene were inserted consecutively between PMID and FLU to tune the energy levels of the frontier molecular orbitals of the dyes. The structural modification broadened the spectral coverage from an onset of 700 nm for zzx-op1 to 750 nm for zzx-op3. The electron-rich EDOT and thiophene lifted up the HOMO (highest occupied molecular orbital) levels of zzx-op2 and zzx-op3, making their potential more negative than zzx-op1. When three dyes were employed in p-type DSCs with I(-)/I3(-) as a redox couple and NiO nanoparticles as hole materials, zzx-op1 exhibited impressive energy conversion efficiency of 0.184% with the open-circuit voltage (VOC) of 112 mV and the short-circuit current density (JSC) of 4.36 mA cm(-2) under AM 1.5G condition. Density functional theory calculations, transient photovoltage decay measurements, and electrochemical impedance spectroscopic studies revealed that zzx-op1 sensitized solar cell exhibited much higher charge injection efficiency (90.3%) than zzx-op2 (53.9%) and zzx-op3 (39.0%), indicating a trade-off between spectral broadening and electron injection driving force in p-type DSCs.

  16. Absorbant materials

    Quetier, Monique.

    1978-11-01

    Absorbants play a very important part in the nuclear industry. They serve for the control, shut-down and neutron shielding of reactors and increase the capacity of spent fuel storage pools and of special transport containers. This paper surveys the usual absorbant materials, means of obtainment, their essential characteristics relating to their use and their behaviour under neutron irradiation [fr

  17. Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

    Yang, Xinbo; Aydin, Erkan; Xu, Hang; Kang, Jingxuan; Hedhili, Mohamed N.; Liu, Wenzhu; Wan, Yimao; Peng, Jun; Samundsett, Christian; Cuevas, Andres; De Wolf, Stefaan

    2018-01-01

    novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties

  18. Gradient SiNO anti-reflective layers in solar selective coatings

    Ren, Zhifeng; Cao, Feng; Sun, Tianyi; Chen, Gang

    2017-08-01

    A solar selective coating includes a substrate, a cermet layer having nanoparticles therein deposited on the substrate, and an anti-reflection layer deposited on the cermet layer. The cermet layer and the anti-reflection layer may each be formed of intermediate layers. A method for constructing a solar-selective coating is disclosed and includes preparing a substrate, depositing a cermet layer on the substrate, and depositing an anti-reflection layer on the cermet layer.

  19. Measures for diffusion of solar PV in selected African countries

    Nygaard, Ivan; Hansen, Ulrich Elmer; Mackenzie, Gordon A.

    2017-01-01

    that governments’ strategies to promoting solar PV are moving from isolated projects towards frameworks for market development and that there are high expectations to upgrading in the PV value chain through local assembly of panels and local production of other system elements. Commonly identified measures include......This paper investigates how African governments are considering supporting and promoting the diffusion of solar PV. This issue is explored by examining so-called ‘technology action plans (TAPs)’, which were main outputs of the Technology Needs Assessment project implemented in 10 African countries...... from 2010 to 2013. The paper provides a review of three distinct but characteristic trajectories for PV market development in Kenya (private-led market for solar home systems), Morocco (utility-led fee-for service model) and Rwanda (donorled market for institutional systems). The paper finds...

  20. Measures for diffusion of solar PV in selected African countries

    Nygaard, Ivan; Hansen, Ulrich Elmer; Mackenzie, Gordon; Pedersen, Mathilde Brix

    2017-08-01

    This paper investigates how African governments are considering supporting and promoting the diffusion of solar PV. This issue is explored by examining so-called 'technology action plans (TAPs)', which were main outputs of the Technology Needs Assessment project implemented in 10 African countries from 2010 to 2013. The paper provides a review of three distinct but characteristic trajectories for PV market development in Kenya (private-led market for solar home systems), Morocco (utility-led fee-for service model) and Rwanda (donor-led market for institutional systems). The paper finds that governments' strategies to promoting solar PV are moving from isolated projects towards frameworks for market development and that there are high expectations to upgrading in the PV value chain through local assembly of panels and local production of other system elements. Commonly identified measures include support to: local production; financing schemes; tax exemptions; establishment and reinforcement of standards; technical training; and research and development.

  1. A Novel Extension Decision-Making Method for Selecting Solar Power Systems

    Meng-Hui Wang

    2013-01-01

    Full Text Available Due to the complex parameters of a solar power system, the designer not only must think about the load demand but also needs to consider the price, weight, and annual power generating capacity (APGC and maximum power of the solar system. It is an important task to find the optimal solar power system with many parameters. Therefore, this paper presents a novel decision-making method based on the extension theory; we call it extension decision-making method (EDMM. Using the EDMM can make it quick to select the optimal solar power system. The paper proposed this method not only to provide a useful estimated tool for the solar system engineers but also to supply the important reference with the installation of solar systems to the consumer.

  2. Computer simulation of the optical properties of high-temperature cermet solar selective coatings

    Nejati, M. Reza [K.N. Toosi Univ. of Technology, Dept. of Mechanical Engineering, Tehran (Iran); Fathollahi, V.; Asadi, M. Khalaji [AEOI, Center for Renewable Energy Research and Applications (CRERA), Tehran (Iran)

    2005-02-01

    A computer simulation is developed to calculate the solar absorptance and thermal emittance of various configurations of cermet solar selective coatings. Special attention has been paid to those material combinations, which are commonly used in high-temperature solar thermal applications. Moreover, other material combinations such as two-, three- and four-cermet-layer structures as solar selective coatings have been theoretically analyzed by computer simulation using three distinct physical models of Ping Sheng, Maxwell-Garnett and Bruggeman. The novel case of two-cermet-layer structure with different cermet components has also been investigated. The results were optimized by allowing the program to manipulate the metal volume fraction and thickness of each layer and the results compared to choose the best possible configuration. The calculated results are within the range of 0.91-0.97 for solar absorptance and 0.02-0.07 for thermal emittance at room temperature. (Author)

  3. Detection of non-absorbing charge dynamics via refractive index change in dye-sensitized solar cells.

    Kuwahara, Shota; Hata, Hiroaki; Taya, Soichiro; Maeda, Naotaka; Shen, Qing; Toyoda, Taro; Katayama, Kenji

    2013-04-28

    The carrier dynamics in dye-sensitized solar cells was investigated by using the transient grating, in addition to the transient absorption method and transient photocurrent method on the order of microseconds to seconds. The signals for the same sample were obtained under a short-circuit condition to compare the carrier dynamics via refractive index change with the transient photocurrent measurement. Optically silent carrier dynamics by transient absorption have been successfully observed via a refractive index change. The corresponding signal components were originated from the charge dynamics at the solid/liquid interface, especially on the liquid side; rearrangement or diffusion motion of charged redox species occurred when the injected electrons were trapped at the TiO2 surface and when the electron-electrolyte recombination occurred at the interface. The assignments were confirmed from the dependence on the viscosity of the solvent and the presence of 4-tert-butyl pyridine. As the viscosity of the solvent increased, the rearrangement and the motion of the charged redox species were delayed. Since the rearrangement dynamics was changed by the presence of 4-tert-butyl pyridine, it affected not only the TiO2 surface but also the redox species close to the interface.

  4. CZTS absorber layer for thin film solar cells from electrodeposited metallic stacked precursors (Zn/Cu-Sn)

    Khalil, M.I., E-mail: mdibrahim.khalil@polimi.it [Dipartimento di Chimica, Materiali e Ing. Chimica “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano (Italy); Atici, O. [Dipartimento di Chimica, Materiali e Ing. Chimica “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano (Italy); Lucotti, A. [Dipartimento di Chimica, Materiali e Ing. Chimica “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Binetti, S.; Le Donne, A. [Department of Materials Science and Solar Energy Research Centre (MIB-SOLAR), University of Milano- Bicocca, Via Cozzi 53, 20125 Milano (Italy); Magagnin, L., E-mail: luca.magagnin@polimi.it [Dipartimento di Chimica, Materiali e Ing. Chimica “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131 Milano (Italy)

    2016-08-30

    Highlights: • CZTS absorber layer was fabricated by electrodeposition—annealing route from stacked bilayer precursor (Zn/Cu-Sn). • Different characterization techniques have ensured the well formed Kesterite CZTS along the film thickness also. • Two different excitation wavelengths of laser lines (514.5 and 785 nm) have been used for the Raman characterization of the films. • No significant Sn loss is observed in CZTS films after the sulfurization of the stacked bilayer precursors. • Photoluminescence spectroscopy reveals the PL peak of CZTS at 1.15 eV at low temperature (15 K). - Abstract: In the present work, Kesterite-Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films were successfully synthesized from stacked bilayer precursor (Zn/Cu-Sn) through electrodeposition-annealing route. Adherent and homogeneous Cu-poor, Zn-rich stacked metal Cu-Zn-Sn precursors with different compositions were sequentially electrodeposited, in the order of Zn/Cu-Sn onto Mo foil substrates. Subsequently, stacked layers were soft annealed at 350 °C for 20 min in flowing N{sub 2} atmosphere in order to improve intermixing of the elements. Then, sulfurization was completed at 585 °C for 15 min in elemental sulfur environment in a quartz tube furnace with N{sub 2} atmosphere. Morphological, compositional and structural properties of the films were investigated using SEM, EDS and XRD methods. Raman spectroscopy with two different excitation lines (514.5 and 785 nm), has been carried out on the sulfurized films in order to fully characterize the CZTS phase. Higher excitation wavelength showed more secondary phases, but with low intensities. Glow discharge optical emission spectroscopy (GDOES) has also been performed on films showing well formed Kesterite CZTS along the film thickness as compositions of the elements do not change along the thickness. In order to investigate the electronic structure of the CZTS, Photoluminescence (PL) spectroscopy has been carried out on the films, whose

  5. PERFORMANCE EVALUATION OF SOLAR COLLECTORS USING A SOLAR SIMULATOR

    M. Norhafana; Ahmad Faris Ismail; Z. A. A. Majid

    2015-01-01

    Solar water heating systems is one of the applications of solar energy. One of the components of a solar water heating system is a solar collector that consists of an absorber. The performance of the solar water heating system depends on the absorber in the solar collector. In countries with unsuitable weather conditions, the indoor testing of solar collectors with the use of a solar simulator is preferred. Thus, this study is conducted to use a multilayered absorber in the solar collector of...

  6. Selecting Solar. Insights into Residential Photovoltaic (PV) Quote Variation

    Davidson, Carolyn [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-01

    This analysis leverages available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.

  7. Behavior of Electrochemically Prepared CuInSe{sub 2} as Photovoltaic Absorber in thin Film Solar Cells; Comportamiento del CuInSe{sub 2} Basado en Precursores Electrodepositados como Absorbente Fotovoltaico en Celulas Solares de Lamina Delgada

    Guillen, C; Martinez, M A; Dona, J M; Herrero, J; Gutierrez, M T [Ciemat.Madrid (Spain)

    2000-07-01

    Two different objective have been pursued in the present investigation: (1) optimization of the CuInSe{sub 2} preparation parameters from electrodeposited precursors, and (2) evaluation of their photovoltaic behavior by preparing and enhancing Mo/CuInSe{sub 2}/CdS/TCO devices. When Cu-In-Se precursors are directly electrodeposited, the applied potential fit is essential to improve the photovoltaic performance. Suitable absorbers have been also obtained by evaporing an In layer onto electrodeposited Cu-Se precursors. In this case, the substrate temperature during evaporation determines the CuInSe{sub 2} quality. Similar results have been reached by substituting typical Mo-Coated glass substrates by flexible Mo foils. Different TCO tested (ZnO and ITO) have been found equivalent as front electrical contact in the devices. Solar cell performance can be improved by annealing in air at 200 degree centigree. (Author) 46 refs.

  8. High-temperature hydrogenation of pure and silver-decorated titanate nanotubes to increase their solar absorbance for photocatalytic applications

    Plodinec, Milivoj [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Gajović, Andreja, E-mail: gajovic@irb.hr [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Jakša, Gregor; Žagar, Kristina; Čeh, Miran [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia)

    2014-04-05

    Graphical abstract: The aim of the work is to study how annealing in a reducing atmosphere of titanate nanotubes (TiNT) and Ag decorated titanate nanotubes (TiNT@Ag) influenced on their structure, morphology, phase transitions, UV–ViS-NIR absorbance and photocatalytic activity. An increase of photocatalytic activity after a heat treatment in a reducing atmosphere was observed in the TiNT and TiNT@Ag. We found that the hydrogenated TiNT@Ag samples (TiNT@Ag-HA) had a two-times higher photodegradation impact on the caffeine than the TiNT samples, which is a consequence of the increased absorption of visible light and the synergetic effects between the silver and the TiO{sub 2} nanoparticles that increase the efficiency of the formation of electron–hole pairs and the charge transfer to the surface of the nanoparticles. -- Highlights: • Titanate nanotubes with and without Ag nanoparticles were hydrogenated at 550 °C. • TiO{sub 2} nanostructures obtained by hydrogenation have core–shell structure. • Hydrogenated samples show absorption in the visible spectral region. • Hydrogenated Ag decorated sample show stronger absorption in visible than in UV. • Photocatalytic efficiency is improved by hydrogenation and by Ag nanoparticles. -- Abstract: Titanate nanotubes (TiNTs) and silver-decorated titanate nanotubes (TiNTs@Ag) were synthesized using the hydrothermal method. In the decorated nanotubes the silver particles were obtained by the photoreduction of AgNO{sub 3} under UV light. Pure and Ag-decorated nanotubes were high-temperature heat treated at 550 °C in a hydrogen atmosphere and the “core–shell”-structured TiO{sub 2} nanoparticles were formed. For the structural characterization of all the titanate nanostructures we used conventional and analytical transmission electron microscopy (TEM) techniques, X-ray diffraction (XRD) and Raman spectroscopy. The Ag-decorated titanate nanostructures were additionally studied by X-ray photo

  9. An investigation of heat transfer augmentation and friction characteristics in solar air heater duct with V-shaped wire as artificial roughness on absorber plate

    Madhukeshwara, N. [Department of Mechanical Engineering, B.I.E.T, Davanagere, Karnataka (India); Prakash, E.S. [Department of Studies in Mechanical Engineering, U.B.D.T.C.E, Davanagere, Karnataka (India)

    2013-07-01

    An experimental investigation of heat transfer augmentation and friction characteristics of fully developed turbulent flow in a rectangular duct of solar air heater with absorber plate having V-shaped wire ribs as artificial roughness on its underside is carried out. The investigation covers wide range of different parameters of wire ribbed roughness: relative roughness pitch (p/e) from 10 to 40, relative roughness height (e/Dh) from 0.01 to 0.04 and angle of attack of flow from 20° to 90°. Duct aspect ratio (W/B) is kept 5 and Reynolds number (Re) is varied from 2,500 to 8,500. The heat transfer and friction factor values obtained are compared with those of smooth duct under similar flow conditions. Expressions are developed for Nusselt number and friction factor for the roughness geometry. Enhancement of Nusselt number and friction factor for roughened duct are 1.5 and 2.7 times of smooth duct respectively.

  10. NOMINAL VALUES FOR SELECTED SOLAR AND PLANETARY QUANTITIES: IAU 2015 RESOLUTION B3

    Prša, Andrej; Harmanec, Petr; Torres, Guillermo; Mamajek, Eric; Asplund, Martin; Capitaine, Nicole; Christensen-Dalsgaard, Jørgen; Depagne, Éric; Haberreiter, Margit; Hekker, Saskia; Hilton, James; Kopp, Greg

    2016-01-01

    In this brief communication we provide the rationale for and the outcome of the International Astronomical Union (IAU) resolution vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015, on recommended nominal conversion constants for selected solar and planetary properties. The problem addressed by the resolution is a lack of established conversion constants between solar and planetary values and SI units: a missing standard has caused a proliferation of solar values (e.g., solar radius, solar irradiance, solar luminosity, solar effective temperature, and solar mass parameter) in the literature, with cited solar values typically based on best estimates at the time of paper writing. As precision of observations increases, a set of consistent values becomes increasingly important. To address this, an IAU Working Group on Nominal Units for Stellar and Planetary Astronomy formed in 2011, uniting experts from the solar, stellar, planetary, exoplanetary, and fundamental astronomy, as well as from general standards fields to converge on optimal values for nominal conversion constants. The effort resulted in the IAU 2015 Resolution B3, passed at the IAU General Assembly by a large majority. The resolution recommends the use of nominal solar and planetary values, which are by definition exact and are expressed in SI units. These nominal values should be understood as conversion factors only, not as the true solar/planetary properties or current best estimates. Authors and journal editors are urged to join in using the standard values set forth by this resolution in future work and publications to help minimize further confusion.

  11. NOMINAL VALUES FOR SELECTED SOLAR AND PLANETARY QUANTITIES: IAU 2015 RESOLUTION B3

    Prša, Andrej [Villanova University, Department of Astrophysics and Planetary Science, 800 Lancaster Ave., Villanova, PA 19085 (United States); Harmanec, Petr [Astronomical Institute of the Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, CZ-180 00 Praha 8 (Czech Republic); Torres, Guillermo [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Mamajek, Eric [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Asplund, Martin [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Capitaine, Nicole [SYRTE, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC, LNE, 61 avenue de lObservatoire, F-75014 Paris (France); Christensen-Dalsgaard, Jørgen [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Depagne, Éric [South African Astronomical Observatory, P.O. Box 9 Observatory, Cape Town (South Africa); Haberreiter, Margit [Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center, Dorfstrasse 33, Davos (Switzerland); Hekker, Saskia [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Hilton, James [US Naval Observatory, 3450 Massachusetts Ave. NW, Washington, DC 20392-5420 (United States); Kopp, Greg [Laboratory for Atmospheric and Space Physics, 1234 Innovation Drive, Boulder, CO 80303-7814 (United States); and others

    2016-08-01

    In this brief communication we provide the rationale for and the outcome of the International Astronomical Union (IAU) resolution vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015, on recommended nominal conversion constants for selected solar and planetary properties. The problem addressed by the resolution is a lack of established conversion constants between solar and planetary values and SI units: a missing standard has caused a proliferation of solar values (e.g., solar radius, solar irradiance, solar luminosity, solar effective temperature, and solar mass parameter) in the literature, with cited solar values typically based on best estimates at the time of paper writing. As precision of observations increases, a set of consistent values becomes increasingly important. To address this, an IAU Working Group on Nominal Units for Stellar and Planetary Astronomy formed in 2011, uniting experts from the solar, stellar, planetary, exoplanetary, and fundamental astronomy, as well as from general standards fields to converge on optimal values for nominal conversion constants. The effort resulted in the IAU 2015 Resolution B3, passed at the IAU General Assembly by a large majority. The resolution recommends the use of nominal solar and planetary values, which are by definition exact and are expressed in SI units. These nominal values should be understood as conversion factors only, not as the true solar/planetary properties or current best estimates. Authors and journal editors are urged to join in using the standard values set forth by this resolution in future work and publications to help minimize further confusion.

  12. improvement to the design of a solid absorption solar refrigerator

    user

    on the coupling of auxiliary heating systems to the solar powered refrigerator. ... the efficiency, developing a field prototype and providing auxiliary heating to the ... of a selective surface for the collector plate, air leakages and low absorber ...

  13. Multi-criteria analysis on how to select solar radiation hydrogen production system

    Badea, G.; Naghiu, G. S., E-mail: naghiu.george@gmail.com; Felseghi, R.-A.; Giurca, I., E-mail: giurca-ioan@yahoo.com [Technical University of Cluj-Napoca, Faculty of Building Services Engineering, Boulevard December 21, no. 128-130, Cluj-Napoca, 400604 (Romania); Răboacă, S. [National R& D Institute for Cryogenic and Isotopic Technologies, str. Uzinei, no. 4, Rm. Vălcea, 240050 (Romania); Aşchilean, I. [SC ACI Cluj SA, Avenue Dorobanţilor, no. 70, Cluj-Napoca, 400609 (Romania)

    2015-12-23

    The purpose of this article is to present a method of selecting hydrogen-production systems using the electric power obtained in photovoltaic systems, and as a selecting method, we suggest the use of the Advanced Multi-Criteria Analysis based on the FRISCO formula. According to the case study on how to select the solar radiation hydrogen production system, the most convenient alternative is the alternative A4, namely the technical solution involving a hydrogen production system based on the electrolysis of water vapor obtained with concentrated solar thermal systems and electrical power obtained using concentrating photovoltaic systems.

  14. Selective dissolution of halide perovskites as a step towards recycling solar cells.

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-05-23

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb(2+) cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

  15. Selective dissolution of halide perovskites as a step towards recycling solar cells

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-05-01

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

  16. Sound Absorbers

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  17. Formation of black glass to be used in solar collectors as absorbent and CuO and Fe{sub 2}O{sub 3}'s effect on this glass

    Colak, Sadiye Cetinkaya; Birdogan, Selcuk; Aral, Ertunc; Kilic, Gokhan [Eskisehir Osmangazi University, Faculty of Science and Arts, Physics Department, Meselik, 26480 Eskisehir (Turkey)

    2009-06-15

    Solar energy has the highest potential among novel and renewable energies. In order for solar energy to be used it should first be collected. In this study, a black glass was formed by doping silicate glass with Co{sub 3}O{sub 4} at a high concentration to be used as absorbent, and in addition, this black glass was also doped with CuO and Fe{sub 2}O{sub 3}. Optical absorptions, electrical conductivities, thermal diffusion coefficients, SEM images and EDX spectra of all glasses were obtained and effects of transition metal oxides on glass were examined. (author)

  18. Relationship between open-circuit voltage in Cu(In,Ga)Se{sub 2} solar cell and peak position of (220/204) preferred orientation near its absorber surface

    Chantana, J., E-mail: jakapan@fc.ritsumei.ac.jp; Minemoto, T. [Department of Electrical and Electronic Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Watanabe, T.; Teraji, S.; Kawamura, K. [Environment and Energy Research Center, Nitto Denko Corporation, 2-8 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-11-25

    Cu(In,Ga)Se{sub 2} (CIGS) absorbers with various Ga/III, Ga/(In+Ga), profiles are prepared by the so-called “multi-layer precursor method” using multi-layer co-evaporation of material sources. It is revealed that open-circuit voltage (V{sub OC}) of CIGS solar cell is primarily dependent on averaged Ga/III near the surface of its absorber. This averaged Ga/III is well predicted by peak position of (220/204) preferred orientation of CIGS film near its surface investigated by glancing-incidence X-ray diffraction with 0.1° incident angle. Finally, the peak position of (220/204) preferred orientation is proposed as a measure of V{sub OC} before solar cell fabrication.

  19. Solar selective performance of metal nitride/oxynitride based magnetron sputtered thin film coatings: a comprehensive review

    Ibrahim, Khalil; Taha, Hatem; Mahbubur Rahman, M.; Kabir, Humayun; Jiang, Zhong-Tao

    2018-03-01

    Since solar-thermal collectors are considered to be the most direct way of converting solar energy into usable forms, in the last few years growing attention has been paid to the development of transition metal nitride and metal oxynitride based thin film selective surfaces for solar-thermal collectors, in order to harvest more solar energy. A solar-thermal energy system, generally, shows very high solar absorption of incident solar radiation from the solar-thermal collectors in the visible range (0.3 to 2.5 μm) and extremely low thermal losses through emission (or high reflection) in the infrared region (≥2.5 μm). The efficiency of a solar-thermal energy conversion system can be improved by the use of solar selective surfaces consisting of novel metallic nanoparticles embedded in metal nitride/oxynitride systems. In order to enhance the effectiveness of solar-thermal devices, solar selective surfaces with high thermal stability are a prerequisite. Over the years, substantial efforts have been made in the field of solar selective surfaces to attain higher solar absorptance and lower thermal emittance in high temperature (above 400 °C) applications. In this article, we review the present state-of-the-art transition metal nitride and/or oxynitride based vacuum sputtered nanostructured thin film coatings, with respect to their optical and solar selective surface applications. We have also summarized the solar selectivity data from recently published investigations, including discussion on some potential applications for these materials.

  20. Dependence of the coefficient of environmental thermal losses of radiation-absorbing thermal exchange panels of flat solar collectors for heating heat-transfer fluid from their average operating and ambient temperatures

    Avezova, N.R.; Avezov, R.R.

    2015-01-01

    The approximation formula is derived for calculating the normalized coefficient of thermal losses of flat solar collectors (FSCs) for heating heat-transfer fluid (HTF). These are used in hot water supply systems in the warmer part of the year, depending on the average working surface temperature of their radiation-absorbing thermal exchange panels (RATEPs) (t"-_w_s_r) and the ambient temperature (t_a_m_b) in their realistic variation range. (author)

  1. Selecting Solar: Insights into Residential Photovoltaic (PV) Quote Variation

    Davidson, Carolyn [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-01

    Before investing in a system, a prospective PV customer must not only have initial concept 'buy in,' but also be able to evaluate the tradeoffs associated with different system parameters. Prospective customers might need to evaluate disparate costs for each system attribute by comparing multiple bids. The difficulty of making such an evaluation with limited information can create a cognitive barrier to proceeding with the investment. This analysis leverages recently available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.

  2. A Two-Step Absorber Deposition Approach To Overcome Shunt Losses in Thin-Film Solar Cells: Using Tin Sulfide as a Proof-of-Concept Material System

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul H.; Hartman, Katy; Brandt, Riley E.; Polizzotti, Alex; Yang, Chuanxi; Moriarty, Tom; Gradečak, Silvija; Gordon, Roy G.; Buonassisi, Tonio

    2016-08-31

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to reproducibly test promising candidates for high-performing PV devices. Many early-stage devices are prone to device shunting due to pinholes in the absorber layer, producing 'false-negative' results. Here, we demonstrate a device engineering solution toward a robust device architecture, using a two-step absorber deposition approach. We use tin sulfide (SnS) as a test absorber material. The SnS bulk is processed at high temperature (400 degrees C) to stimulate grain growth, followed by a much thinner, low-temperature (200 degrees C) absorber deposition. At a lower process temperature, the thin absorber overlayer contains significantly smaller, densely packed grains, which are likely to provide a continuous coating and fill pinholes in the underlying absorber bulk. We compare this two-step approach to the more standard approach of using a semi-insulating buffer layer directly on top of the annealed absorber bulk, and we demonstrate a more than 3.5x superior shunt resistance Rsh with smaller standard error ..sigma..Rsh. Electron-beam-induced current (EBIC) measurements indicate a lower density of pinholes in the SnS absorber bulk when using the two-step absorber deposition approach. We correlate those findings to improvements in the device performance and device performance reproducibility.

  3. Shock absorber

    Nemeth, J.D.

    1981-01-01

    A shock absorber for the support of piping and components in a nuclear power plant is described. It combines a high degree of stiffness under sudden shocks, e.g. seismic disturbances, with the ability to allow for thermal expansion without resistance when so required. (JIW)

  4. Study of an optimization of regeneration for an absorbent used in the solar desiccant cooling system; Taiyonetsu riyo desiccant reibo ni mochiirareru kyushuzai saisei tokusei no saitekika ni kansuru kenkyu

    Saito, Y [Osaka Institute of Technology, Osaka (Japan)

    1997-11-25

    A desiccant cooling system uses concentrated aqueous solution of an absorbent to reduce humidity, hence the resultant absorbent solution becomes dilute. Regeneration of the dilute solution uses solar heat, where the regeneration characteristics are affected by solution temperature, vapor pressure, water content, air-liquid flow rate, and other factors. Therefore, mutual relationship among these different factors were investigated, and an optimum operating condition was discussed. The regeneration characteristics of the absorbent is strongly affected by temperature of triethylene glycol (TEG). This is because vapor pressure, Ps, in the TEG aqueous solution increases as the TEG temperature rises. This means that preheating the solution is effective in regenerating the absorbent. As the regeneration progresses, the water content, Ww, decreases, and the regeneration rate decreases. This is because of reduction in the Ps in association with decrease in the Ww of the TEG. This suggests that it is important in the absorbent regeneration to reduce flow rate of the TEG aqueous solution as low as possible. Raised air temperature reduces difference in vapor partial pressure between the TEG and the air, resulting in reduced regeneration rate. 5 refs., 9 figs.

  5. Analysis of selected microflares observed by SphinX over the last minimum of solar activity

    Siarkowski, Marek; Sylwester, Janusz; Sylwester, Barbara; Gryciuk, Magdalena

    The Solar Photometer in X-rays (SphinX) was designed to observe soft X-ray solar emission in the energy range between 1 keV and 15 keV with the resolution better than 0.5 keV. The instrument operated from February until November 2009 aboard CORONAS-Photon satellite, during the phase of exceptionally low minimum of solar activity. Here we use SphinX data for analysis of selected microflare-class events. We selected events of unusual lightcurves or location. Our study involves determination of temporal characteristics (times of start, maximum and end of flares) and analysis of physical conditions in flaring plasma (temperature, emission measure). Dedicated method has been used in order to remove emission not related to flare. Supplementary information about morphology and evolution of investigated events has been derived from the analysis of XRT/Hinode and SECCHI /STEREO images.

  6. Visible light broadband perfect absorbers

    Jia, X. L.; Meng, Q. X.; Yuan, C. X.; Zhou, Z. X.; Wang, X. O., E-mail: wxo@hit.edu.cn [School of Science, Harbin Institute of Technology, Harbin 150001 (China)

    2016-03-15

    The visible light broadband perfect absorbers based on the silver (Ag) nano elliptical disks and holes array are studied using finite difference time domain simulations. The semiconducting indium silicon dioxide thin film is introduced as the space layer in this sandwiched structure. Utilizing the asymmetrical geometry of the structures, polarization sensitivity for transverse electric wave (TE)/transverse magnetic wave (TM) and left circular polarization wave (LCP)/right circular polarization wave (RCP) of the broadband absorption are gained. The absorbers with Ag nano disks and holes array show several peaks absorbance of 100% by numerical simulation. These simple and flexible perfect absorbers are particularly desirable for various potential applications including the solar energy absorber.

  7. Selective production of hydrogen peroxide and oxidation of hydrogen sulfide in an unbiased solar photoelectrochemical cell

    Zong, Xu; Chen, Hongjun; Seger, Brian

    2014-01-01

    A solar-to-chemical conversion process is demonstrated using a photoelectrochemical cell without external bias for selective oxidation of hydrogen sulfide (H2S) to produce hydrogen peroxide (H2O2) and sulfur (S). The process integrates two redox couples anthraquinone/anthrahydroquinone and I−/I3......−, and conceptually illustrates the remediation of a waste product for producing valuable chemicals....

  8. Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

    Ali, Haider; Yang, Xinbo; Weber, Klaus; Schoenfeld, Winston V.; Davis, Kristopher O.

    2017-01-01

    In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21

  9. A Hybrid Multiple-Criteria Decision-Making Approach for Photovoltaic Solar Plant Location Selection

    Amy H. I. Lee

    2017-01-01

    Full Text Available Due to decaying fossil resource and increasing environmental consciousness, the demand of renewable energy resources is escalating these days. Photovoltaic solar energy is one of the most popular renewable energy resources in places where sunlight is abundant. The selection of a desirable location for constructing a photovoltaic solar plant is the first and one of the most important stages in the plant construction to provide a long-term energy production. In this paper, a comprehensive multiple-criteria decision-making model, which incorporates the interpretive structural modeling (ISM, fuzzy analytic network process (FANP and VIKOR (VlseKriterijumska OptimizacijaI Kompromisno Resenje in Serbian,meaning multi-criteria optimization and compromise solution, is proposed to select the most suitable photovoltaic solar plant location. The ISM is applied first to determine the interrelationships among the criteria and among the sub-criteria,andtheresults are used to construct a decision-making network. The FANP is applied next to solve the network and to calculate the importance weights of the sub-criteria. Finally, the VIKOR is adopted to determine the ranking of the photovoltaic solar plant locations. The proposed model is applied in a case study in evaluating photovoltaic solar plant locations in Taiwan. By applying the proposed model, decision makers can have a better thinking process and make more appropriate decisions justifiably.

  10. Thermo-economic analysis and selection of working fluid for solar organic Rankine cycle

    Desai, Nishith B.; Bandyopadhyay, Santanu

    2016-01-01

    Highlights: • Concentrating solar power plant with organic Rankine cycle. • Thermo-economic analysis of solar organic Rankine cycle. • Performance evaluation for different working fluids. • Comparison diagram to select appropriate working fluid. - Graphical Abstract: Display Omitted - Abstract: Organic Rankine cycle (ORC), powered by line-focusing concentrating solar collectors (parabolic trough collector and linear Fresnel reflector), is a promising option for modular scale. ORC based power block, with dry working fluids, offers higher design and part-load efficiencies compared to steam Rankine cycle (SRC) in small-medium scale, with temperature sources up to 400 °C. However, the cost of ORC power block is higher compared to the SRC power block. Similarly, parabolic trough collector (PTC) system has higher optical efficiency and higher cost compared to linear Fresnel reflector (LFR) system. The thermodynamic efficiencies and power block costs also vary with working fluids of the Rankine cycle. In this paper, thermo-economic comparisons of organic Rankine and steam Rankine cycles powered by line-focusing concentrating solar collectors are reported. A simple selection methodology, based on thermo-economic analysis, and a comparison diagram for working fluids of power generating cycles are also proposed. Concentrating solar power plants with any collector technology and any power generating cycle can be compared using the proposed methodology.

  11. Mechanical shock absorber

    Vrillon, Bernard.

    1973-01-01

    The mechanical shock absorber described is made of a constant thickness plate pierced with circular holes regularly distributed in such a manner that for all the directions along which the strain is applied during the shock, the same section of the substance forming the plate is achieved. The shock absorber is made in a metal standing up to extensive deformation before breaking, selected from a group comprising mild steels and austenitic stainless steels. This apparatus is used for handling pots of fast neutron reactor fuel elements [fr

  12. Carbon-in-silica composite selective solar absorbers: a determination of composition and dielectic properties - SAIP Poster

    Katumba, G

    2006-07-01

    Full Text Available . The Bruggeman and Maxwell-Garnett EMAs could not model the optical properties of these materials; neither could the Bergman-Milton bounds approach. A generalised Bergman representation is applied on these carbon-in-silica samples with successful fitting between...

  13. Use of magnesium silicate as a selective absorbent in radioimmunological method of determination of insulin level in human serum

    Bogoniowska, Z; Stelmasiak, T [Wojskowy Instytut Higieny i Epidemiologii, Warsaw (Poland)

    1974-01-01

    The authors present a radioimmunological method for determination of insulin (IRI) level in the human serum using magnesium silicate (talc) as adsorbent. The method is based on the phenomenon of selective adsorption of the free radioactive hormone. The optimal parameters for the method were determined. The serum level of IRI in clinically healthy subjects after oral glucose loading was established. The obtained results were compared with the results obtained by the radioimmunological method of double antibodies in stochastically grouped samples.

  14. Production of solar chemicals: gaining selectivity with hybrid molecule/semiconductor assemblies.

    Hennessey, Seán; Farràs, Pau

    2018-05-29

    Research on the production of solar fuels and chemicals has rocketed over the past decade, with a wide variety of systems proposed to harvest solar energy and drive chemical reactions. In this Feature Article we have focused on hybrid molecule/semiconductor assemblies in both powder and supported materials, summarising recent systems and highlighting the enormous possibilities offered by such assemblies to carry out highly demanding chemical reactions with industrial impact. Of relevance is the higher selectivity obtained in visible light-driven organic transformations when using molecular catalysts compared to photocatalytic materials.

  15. Selective deposition contact patterning using atomic layer deposition for the fabrication of crystalline silicon solar cells

    Cho, Young Joon; Shin, Woong-Chul; Chang, Hyo Sik

    2014-01-01

    Selective deposition contact (SDC) patterning was applied to fabricate the rear side passivation of crystalline silicon (Si) solar cells. By this method, using screen printing for contact patterning and atomic layer deposition for the passivation of Si solar cells with Al 2 O 3 , we produced local contacts without photolithography or any laser-based processes. Passivated emitter and rear-contact solar cells passivated with ozone-based Al 2 O 3 showed, for the SDC process, an up-to-0.7% absolute conversion-efficiency improvement. The results of this experiment indicate that the proposed method is feasible for conversion-efficiency improvement of industrial crystalline Si solar cells. - Highlights: • We propose a local contact formation process. • Local contact forms a screen print and an atomic layer deposited-Al 2 O 3 film. • Ozone-based Al 2 O 3 thin film was selectively deposited onto patterned silicon. • Selective deposition contact patterning method can increase cell-efficiency by 0.7%

  16. An investigation on the performance characteristics of solar flat plate collector with different selective surface coatings

    Madhukeshwara, N. [Department of Mechanical Engineering, B.I.E.T, Davanagere, Karnataka (India); Prakash, E.S. [Department of Studies in Mechanical Engineering, U.B.D.T.C.E, Davanagere, Karnataka (India)

    2012-07-01

    In the present work, investigations are made to study performance characteristics of solar flat plate collector with different selective surface coatings. Flat plate collector is one of the important solar energy trapping device which uses air or water as working fluid. Of the many solar collector concepts presently being developed, the relative simple flat plate solar collector has found the widest application so far. Its characteristics are known, and compared with other collector types, it is the easiest and least expensive to fabricate, install, and maintain. Moreover, it is capable of using both the diffuse and the direct beam solar radiation. For residential and commercial use, flat plate collectors can produce heat at sufficiently high temperatures to heat swimming pools, domestic hot water, and buildings; they also can operate a cooling unit, particularly if the incident sunlight is increased by the use of reflector. Temperatures up to 70 C are easily attained by flat plate collectors. With very careful engineering using special surfaces, reflectors to increase the incident radiation and heat resistant materials, higher operating temperatures are feasible.

  17. Tantalum Nitride Electron-Selective Contact for Crystalline Silicon Solar Cells

    Yang, Xinbo

    2018-04-19

    Minimizing carrier recombination at contact regions by using carrier‐selective contact materials, instead of heavily doping the silicon, has attracted considerable attention for high‐efficiency, low‐cost crystalline silicon (c‐Si) solar cells. A novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties to the silicon surface, due to their small conduction band offset and large valence band offset. Thin TaNx interlayers provide moderate passivation of the silicon surfaces while simultaneously allowing a low contact resistivity to n‐type silicon. A power conversion efficiency (PCE) of over 20% is demonstrated with c‐Si solar cells featuring a simple full‐area electron‐selective TaNx contact, which significantly improves the fill factor and the open circuit voltage (Voc) and hence provides the higher PCE. The work opens up the possibility of using metal nitrides, instead of metal oxides, as carrier‐selective contacts or electron transport layers for photovoltaic devices.

  18. Solar warming systems of water installed in Colombia. Photovoltaic solar systems installed in the Country

    Rodriguez P, F.

    1995-01-01

    Between the systems that operate as of solar energy, the solar collectors to heat water have had wide use and application in the Country. Basically, a solar collector is constituted by: Box, thermal insulator, ducts and transparent roof. Generally, the used materials are the following: As thermal insulator: Polyurethane or glass fiber; as absorbent plate: Copper or aluminum, painting in dull black or selective surfaces; for the ducts: Generally it is used copper pipeline; and for the cover: Common glass or temperate glass

  19. Industrially feasible, dopant-free, carrier-selective contacts for high-efficiency silicon solar cells

    Yang, Xinbo

    2017-05-31

    Dopant-free, carrier-selective contacts (CSCs) on high efficiency silicon solar cells combine ease of deposition with potential optical benefits. Electron-selective titanium dioxide (TiO) contacts, one of the most promising dopant-free CSC technologies, have been successfully implemented into silicon solar cells with an efficiency over 21%. Here, we report further progress of TiO contacts for silicon solar cells and present an assessment of their industrial feasibility. With improved TiO contact quality and cell processing, a remarkable efficiency of 22.1% has been achieved using an n-type silicon solar cell featuring a full-area TiO contact. Next, we demonstrate the compatibility of TiO contacts with an industrial contact-firing process, its low performance sensitivity to the wafer resistivity, its applicability to ultrathin substrates as well as its long-term stability. Our findings underscore the great appeal of TiO contacts for industrial implementation with their combination of high efficiency with robust fabrication at low cost.

  20. Extraction and Analysis of Strontium in Water Sample Using a Sr2+ Selective Polymer as the Absorbent Phase

    Rongjian Ying

    2015-01-01

    Full Text Available A kind of Sr2+ selective resin was applied as an absorption phase to extract Sr2+ ion from an aqueous solution, and the amount of Sr2+ was determined using inductively coupled plasma optical emission spectrometer. Factors, including absorption time, temperature, stirring rate, salt-out effect, desorption, and the pH of the aqueous solution, were investigated to optimize the absorption efficiency of Sr2+. Foreign ions were examined to observe their effects on the absorption behavior of Sr2+. The optimum condition was absorption time at 20 min, pH of aqueous solution 7, temperature of 35°C, and 600 rpm stirring rate. A 10 mL solution of 0.1 mol/L HCl is used as the desorption agent. The linear range of Sr2+ concentrations from 50 to 1200 μg/L was investigated with the slope of 183 μg/L. The limit of detection was 21 μg/L with 4.23% relative standard deviation. The correlation coefficient was found to be 0.9947. Under the optimized conditions, the concentrations of Sr2+ in four water samples were detected by the developed method. We propose that this method effectively extracts strontium ion from environmental water samples.

  1. Ion implantation into amorphous Si layers to form carrier-selective contacts for Si solar cells

    Feldmann, Frank; Mueller, Ralph; Reichel, Christian; Hermle, Martin

    2014-01-01

    This paper reports our findings on the boron and phosphorus doping of very thin amorphous silicon layers by low energy ion implantation. These doped layers are implemented into a so-called tunnel oxide passivated contact structure for Si solar cells. They act as carrier-selective contacts and, thereby, lead to a significant reduction of the cell's recombination current. In this paper we address the influence of ion energy and ion dose in conjunction with the obligatory high-temperature anneal needed for the realization of the passivation quality of the carrier-selective contacts. The good results on the phosphorus-doped (implied V oc = 725 mV) and boron-doped passivated contacts (iV oc = 694 mV) open a promising route to a simplified interdigitated back contact (IBC) solar cell featuring passivated contacts. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Silicon heterojunction solar cell with passivated hole selective MoOx contact

    Battaglia, Corsin; de Nicolás, Silvia Martín; De Wolf, Stefaan; Yin, Xingtian; Zheng, Maxwell; Ballif, Christophe; Javey, Ali

    2014-03-01

    We explore substoichiometric molybdenum trioxide (MoOx, x MoOx, we observe a substantial gain in photocurrent of 1.9 mA/cm2 in the ultraviolet and visible part of the solar spectrum, when compared to a p-type amorphous silicon emitter of a traditional silicon heterojunction cell. Our results emphasize the strong potential for oxides as carrier selective heterojunction partners to inorganic semiconductors.

  3. Artificial Photosystem I and II: Highly Selective solar fuels and tandem photocatalysis

    Ding, Yuchen; Castellanos, Ignacio; Cerkovnik, Logan; Nagpal, Prashant

    2014-03-01

    Artificial photosynthesis, or generation of solar fuels from CO2/H2O, can provide an important alternative for rising CO2 emission and renewable energy generation. In our recent work, composite photocatalysts (CPCs) made from widebandgap nanotubes and different QDs were used to mimic Photosystem II (PS680) and I (PS700), respectively. By tuning the redox potentials using the size, composition and energy band alignment of QDs, we demonstrate highly selective (>90%) and efficient production of ethane, ethanol and acetaldehyde as solar fuels with different wavelengths of light. We also show that this selectivity is a result of precise energy band alignments (using cationic/anionic doping of nanotubes, QD size etc.), confirmed using measurements of electronic density of states, and alignment of higher redox potentials with hot-carriers can also lead to hot-carrier photocatalysis. This wavelength-selective CPCs can have important implications for inexpensive production of solar fuels including alkanes, alcohols, aldehydes and hydrogen, and making tandem structures (red, green, blue) with three CPCs, allowing almost full visible spectrum (410 ~ 730nm) utilization with different fuels produced simultaneously.

  4. Quantitative assessment of selective in-plane shielding of tissues in computed tomography through evaluation of absorbed dose and image quality

    Geleijns, J.; Veldkamp, W.J.H.; Salvado Artells, M.; Lopez Tortosa, M.; Calzado Cantera, A.

    2006-01-01

    This study aimed at assessment of efficacy of selective in-plane shielding in adults by quantitative evaluation of the achieved dose reduction and image quality. Commercially available accessories for in-plane shielding of the eye lens, thyroid and breast, and an anthropomorphic phantom were used for the evaluation of absorbed dose and image quality. Organ dose and total energy imparted were assessed by means of a Monte Carlo technique taking into account tube voltage, tube current, and scanner type. Image quality was quantified as noise in soft tissue. Application of the lens shield reduced dose to the lens by 27% and to the brain by 1%. The thyroid shield reduced thyroid dose by 26%; the breast shield reduced dose to the breasts by 30% and to the lungs by 15%. Total energy imparted (unshielded/shielded) was 88/86 mJ for computed tomography (CT) brain, 64/60 mJ for CT cervical spine, and 289/260 mJ for CT chest scanning. An increase in image noise could be observed in the ranges were bismuth shielding was applied. The observed reduction of organ dose and total energy imparted could be achieved more efficiently by a reduction of tube current. The application of in-plane selective shielding is therefore discouraged. (orig.)

  5. Thin Film Photovoltaic/Thermal Solar Panels

    David JOHNSTON

    2008-01-01

    A solar panel is described.in which thin films of semiconductor are deposited onto a metal substrate.The semiconductor-metal combination forms a thin film photovoltaic cell,and also acts as a reflector,absorber tandem, which acts as a solar selective surface,thus enhancing the solar thermal performance of the collector plate.The use of thin films reduces the distance heat is required to flow from the absorbing surface to the metal plate and heat exchange conduits.Computer modelling demonstrated that,by suitable choice of materials,photovohaic efficiency call be maintained,with thermal performance slishtly reduced,compared to that for thermal-only panels.By grading the absorber layer-to reduce the band gap in the lower region-the thermal performance can be improved,approaching that for a thermal-only solar panel.

  6. Prepared thin laminae of CuInS{sub 2} by means of evaporation in flow modulated for its application like absorbents in solar cells; Laminas delgadas de CuInS{sub 2} preparadas mediante evaporacion en flujo modulado para su aplicacion como absorbentes en celulas solares

    Bollero, A.; Trigo, J. F.; Herrero, J.; Gutierrez, M. T.

    2008-07-01

    The Department of energy of CIEMAT focuses one of its research lines on the preparation of CuInS{sub 2} films to be used as absorber in solar cells. this work shows the influence of the different process parameters (deposition sequence, modulation of the evaporation flux of the constituent elements,...) on the morphology and the optical properties of the final films. A simplified evaporation procedure has allowed the preparation of CuInS{sub 2} films with a low Cu content. this avoids the necessity of applying subsequent toxic treatment for removal of the CuS phase prior to implementation of the film as absorber in the solar cell device. (Author)

  7. Solar radiation on domed roofs

    Faghih, Ahmadreza K.; Bahadori, Mehdi N. [School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran)

    2009-11-15

    Solar radiation received and absorbed by four domed roofs was estimated and compared with that of a flat roof. The domed roofs all had the same base areas, and equal to that of the flat roof. One of the roofs considered was the dome of the St. Peter's Church in Rome. Compared with the other roofs considered, this dome had a higher aspect ratio. It was found that all domed roofs received more solar radiation than the flat roof. Considering glazed tiles to cover a selected dome in Iran and the dome of the St. Peter's Church, it was found that the solar radiation absorbed by these roofs is reduced appreciably. In the case of the dome of St. Peter's Church, the amount of radiation absorbed was roughly equal to that absorbed by the comparable flat roof in the warm months. In the case of the glazed reference dome located in Yazd, Iran (a city with very high solar radiation), the radiation absorbed was less than that of flat roof at all times. In addition to aesthetics, this may be a reason for employing glazed tiles to cover the domes of all mosques, shrines, and other large buildings in Iran. (author)

  8. Refinement in black chrome for use as a solar selective coating

    Mcdonald, G. E.

    1974-01-01

    Black chrome is significant as a solar selective coating because the current extensive use of black chrome in the electroplating industry as a durable decorative finish makes black chrome widely available on a commercial scale and potentially low in cost as a solar selective coating. Black-chrome deposits were modified by underplating with dull nickel or by being plated on rough surfaces. Both of these procedures increased the visible absorptance. There was no change in the infrared reflectance for the dull-nickel - black-chrome combination from that reported for the bright-nickel - black-chrome combination. However, the bright-nickel - black-chrome coating plated on rough surfaces indicated a slight decrease in infrared reflectance. As integrated over the solar spectrum for air mass 2, the reflectance of the dull-nickel - black-chrome coating was 0.077, of the bright-nickel - black-chrome coating plated on a 0.75-micron (30-microinch) surface was 0.070, of the bright-nickel - black-chrome coating plated on a 2.5 micron (100-microinch) surface was 0.064. The corresponding values for the bright-nickel - black-chrome coating on a 0.0125-micron (0.5-microinch) surface, two samples of black nickel, and two samples of Nextrel black paint were 0.132, 0.123, 0.133, and 0.033, respectively.

  9. Techno-Economic Analysis of Solar Water Heating Systems inTurkey.

    Ertekin, Can; Kulcu, Recep; Evrendilek, Fatih

    2008-02-25

    In this study, solar water heater was investigated using meteorological and geographical data of 129 sites over Turkey. Three different collector types were compared in terms of absorber material (copper, galvanized sheet and selective absorber). Energy requirement for water heating, collector performances, and economical indicators were calculated with formulations using observed data. Results showed that selective absorbers were most appropriate in terms of coverage rate of energy requirement for water-heating all over Turkey. The prices of selective, copper and galvanized absorber type's heating systems in Turkey were 740.49, 615.69 and 490.89 USD, respectively. While payback periods (PBPs) of the galvanized absorber were lower, net present values (NPVs) of the selective absorber were higher than the rest. Copper absorber type collectors did not appear to be appropriate based on economical indicators.

  10. Techno-Economic Analysis of Solar Water Heating Systems inTurkey

    Fatih Evrendilek

    2008-02-01

    Full Text Available In this study, solar water heater was investigated using meteorological and geographical data of 129 sites over Turkey. Three different collector types were compared in terms of absorber material (copper, galvanized sheet and selective absorber. Energy requirement for water heating, collector performances, and economical indicators were calculated with formulations using observed data. Results showed that selective absorbers were most appropriate in terms of coverage rate of energy requirement for water-heating all over Turkey. The prices of selective, copper and galvanized absorber type’s heating systems in Turkey were 740.49, 615.69 and 490.89 USD, respectively. While payback periods (PBPs of the galvanized absorber were lower, net present values (NPVs of the selective absorber were higher than the rest. Copper absorber type collectors did not appear to be appropriate based on economical indicators.

  11. Solar building

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  12. GaAs Solar Cells on V-Grooved Silicon via Selective Area Growth: Preprint

    Warren, Emily L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jain, Nikhil [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tamboli, Adele C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Vaisman, Michelle [Yale University; Li, Qiang [Hong Kong University of Science and Technology; Lau, Kei May [Hong Kong University of Science and Technology

    2017-08-31

    Interest in integrating III-Vs onto Si has recently resurged as a promising pathway towards high-efficiency, low-cost tandem photovoltaics. Here, we present a single junction GaAs solar cell grown monolithically on polished Si (001) substrates using V-grooves, selective area growth, and aspect ratio trapping to mitigate defect formation without the use of expensive, thick graded buffers. The GaAs is free of antiphase domains and maintains a relatively low TDD of 4x107 cm-2, despite the lack of a graded buffer. This 6.25 percent-efficient demonstration solar cell shows promise for further improvements to III-V/Si tandems to enable cost-competitive photovoltaics.

  13. Comparative economic performance of selected passive solar heating and cooling technologies

    Rutter, W.

    1981-05-01

    The economic performance of selected passive solar heating and cooling technologies which incorporate energy storage is assessed by using a set of uniform assumptions and methodologies. Where data are available, a given system is assessed at more than one geographical location. Results are obtained in the form of both payback period and net present value for residential applications, and in terms of net present value only for industrial/commercial uses. Results indicate that ventilated trombe walls, solar roof ponds, and certain night effect/floor storage strategies are cost effective, but night effect/rock bed cooling is not. Results also show that, although direct gain out-performs trombe walls in most parts of the country, both direct gain and trombe walls usually produce a net savings in the residential sector. Generally, however, tax regulations result in net economic loss for direct gain and trombe walls used to heat industrial and commercial buildings.

  14. Formation of double-layered TiO2 structures with selectively-positioned molecular dyes for efficient flexible dye-sensitized solar cells

    Kim, Eun Yi; Yu, Sora; Moon, Jeong Hoon; Yoo, Seon Mi; Kim, Chulhee; Kim, Hwan Kyu; Lee, Wan In

    2013-01-01

    Graphical abstract: A novel flexible tandem dye-sensitized solar cell, selectively loading different dyes in discrete layers, was successfully formed on a plastic substrate by transferring the high-temperature-processed N719/TiO 2 over an organic dye-adsorbed TiO 2 film by a typical compression process at room temperature. -- Highlights: • A novel flexible dye-sensitized solar cell, selectively loading two different dyes in discrete layers, was successfully formed on a plastic substrate. • η of the flexible tandem cell obtained by transferring the high-temperature-processed TiO 2 layer was enhanced from 2.91% to 6.86%. • Interface control between two TiO 2 layers is crucial for the efficient transport of photo-injected electrons from the top to bottom TiO 2 layer. -- Abstract: To fabricate flexible dye-sensitized solar cells (DSCs) utilizing full solar spectrum, the double-layered TiO 2 films, selectively loading two different dyes in discrete layers, were formed on a plastic substrate by transferring the high-temperature-processed N719/TiO 2 over an organic dye (TA-St-CA)-sensitized TiO 2 film by a typical compression process at room temperature. It was found that interface control between two TiO 2 layers is crucial for the efficient transport of photo-injected electrons from the N719/TiO 2 to the TA-St-CA/TiO 2 layer. Electron impedance spectra (EIS) and transient photoelectron spectroscopic analyses exhibited that introduction of a thin interfacial TiO 2 layer between the two TiO 2 layers remarkably decreased the resistance at the interface, while increasing the electron diffusion constant (D e ) by ∼10 times. As a result, the photovoltaic conversion efficiency (η) of the flexible tandem DSC was 6.64%, whereas that of the flexible cell derived from the single TA-St-CA/TiO 2 layer was only 2.98%. Another organic dye (HC-acid), absorbing a short wavelength region of solar spectrum, was also applied to fabricate flexible tandem DSC. The η of the cell

  15. Optimal nonimaging integrated evacuated solar collector

    Garrison, John D.; Duff, W. S.; O'Gallagher, Joseph J.; Winston, Roland

    1993-11-01

    A non imaging integrated evacuated solar collector for solar thermal energy collection is discussed which has the lower portion of the tubular glass vacuum enveloped shaped and inside surface mirrored to optimally concentrate sunlight onto an absorber tube in the vacuum. This design uses vacuum to eliminate heat loss from the absorber surface by conduction and convection of air, soda lime glass for the vacuum envelope material to lower cost, optimal non imaging concentration integrated with the glass vacuum envelope to lower cost and improve solar energy collection, and a selective absorber for the absorbing surface which has high absorptance and low emittance to lower heat loss by radiation and improve energy collection efficiency. This leads to a very low heat loss collector with high optical collection efficiency, which can operate at temperatures up to the order of 250 degree(s)C with good efficiency while being lower in cost than current evacuated solar collectors. Cost estimates are presented which indicate a cost for this solar collector system which can be competitive with the cost of fossil fuel heat energy sources when the collector system is produced in sufficient volume. Non imaging concentration, which reduces cost while improving performance, and which allows efficient solar energy collection without tracking the sun, is a key element in this solar collector design.

  16. Liquid metal reactor absorber technology

    Pitner, A.L.

    1990-10-01

    The selection of boron carbide as the reference liquid metal reactor absorber material is supported by results presented for irradiation performance, reactivity worth compatibility, and benign failure consequences. Scram response requirements are met easily with current control rod configurations. The trend in absorber design development is toward larger sized pins with fewer pins per bundle, providing economic savings and improved hydraulic characteristics. Very long-life absorber designs appear to be attainable with the application of vented pin and sodium-bonded concepts. 3 refs., 3 figs

  17. Efficient Regular Perovskite Solar Cells Based on Pristine [70]Fullerene as Electron-Selective Contact.

    Collavini, Silvia; Kosta, Ivet; Völker, Sebastian F; Cabanero, German; Grande, Hans J; Tena-Zaera, Ramón; Delgado, Juan Luis

    2016-06-08

    [70]Fullerene is presented as an efficient alternative electron-selective contact (ESC) for regular-architecture perovskite solar cells (PSCs). A smart and simple, well-described solution processing protocol for the preparation of [70]- and [60]fullerene-based solar cells, namely the fullerene saturation approach (FSA), allowed us to obtain similar power conversion efficiencies for both fullerene materials (i.e., 10.4 and 11.4 % for [70]- and [60]fullerene-based devices, respectively). Importantly, despite the low electron mobility and significant visible-light absorption of [70]fullerene, the presented protocol allows the employment of [70]fullerene as an efficient ESC. The [70]fullerene film thickness and its solubility in the perovskite processing solutions are crucial parameters, which can be controlled by the use of this simple solution processing protocol. The damage to the [70]fullerene film through dissolution during the perovskite deposition is avoided through the saturation of the perovskite processing solution with [70]fullerene. Additionally, this fullerene-saturation strategy improves the performance of the perovskite film significantly and enhances the power conversion efficiency of solar cells based on different ESCs (i.e., [60]fullerene, [70]fullerene, and TiO2 ). Therefore, this universal solution processing protocol widens the opportunities for the further development of PSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Xu, M.; Wachters, A.J.H.; Van Deelen, J.; Mourad, M.C.D.; Buskens, P.J.P.

    2014-01-01

    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

  19. Effect of band-aligned double absorber layers on photovoltaic characteristics of chemical bath deposited PbS/CdS thin film solar cells.

    Ho Yeon, Deuk; Chandra Mohanty, Bhaskar; Lee, Seung Min; Soo Cho, Yong

    2015-09-23

    Here we report the highest energy conversion efficiency and good stability of PbS thin film-based depleted heterojunction solar cells, not involving PbS quantum dots. The PbS thin films were grown by the low cost chemical bath deposition (CBD) process at relatively low temperatures. Compared to the quantum dot solar cells which require critical and multistep complex procedures for surface passivation, the present approach, leveraging the facile modulation of the optoelectronic properties of the PbS films by the CBD process, offers a simpler route for optimization of PbS-based solar cells. Through an architectural modification, wherein two band-aligned junctions are stacked without any intervening layers, an enhancement of conversion efficiency by as much as 30% from 3.10 to 4.03% facilitated by absorption of a wider range of solar spectrum has been obtained. As an added advantage of the low band gap PbS stacked over a wide gap PbS, the devices show stability over a period of 10 days.

  20. Single and multijunction silicon based thin film solar cells on a flexible substrate with absorber layers made by hot-wire CVD

    Li, Hongbo

    2007-09-01

    With the worldwide growing concern about reliable energy supply and the environmental problems of fossil and nuclear energy production, the need for clean and sustainable energy sources is evident. Solar energy conversion, such as in photovoltaic systems, can play a major role in the urgently needed energy transition in electricity production. Solar cells based on thin film silicon and its alloys are a promising candidate that is capable of fulfilling the fast increasing demand of a reliable solar cell supply. The conventional method to deposit silicon thin films is based on plasma enhanced chemical vapour deposition (PECVD) techniques, which have the disadvantage of increasing film inhomogeneity at a high deposition rate when scaling up for the industrial production. In this thesis, we study the possibility of making high efficiency single and multijunction thin film silicon solar cells with the so-called hot-wire CVD technique, in which no strong electromagnetic field is involved in the deposition. Therefore, the up-scaling for industrial production is straightforward. We report and discuss our findings on the correlation of substrate surface rms roughness and the main output parameter of a solar cell, the open circuit voltage Voc of c-Si:H n i p cells. By considering all the possible reasons that could influence the Voc of such cells, we conclude that the near linear correlation of Voc and substrate surface rms roughness is the result the two most probable reasons: the unintentional doping through the cracks originated near the valleys of the substrate surface due to the in-diffusion of impurities, and the high density electrical defects formed by the collision of columnar silicon structures. Both of them relate to the morphology of substrate surface. Therefore, to have the best cell performance on a rough substrate surface, a good control on the substrate surface morphology is necessary. Another issue influencing the performance of c-Si:H solar cells is the

  1. Material Selection for Dye Sensitized Solar Cells Using Multiple Attribute Decision Making Approach

    Sarita Baghel

    2014-01-01

    Full Text Available Dye sensitized solar cells (DSCs provide a potential alternative to conventional p-n junction photovoltaic devices. The semiconductor thin film plays a crucial role in the working of DSC. This paper aims at formulating a process for the selection of optimum semiconductor material for nanostructured thin film using multiple attribute decision making (MADM approach. Various possible available semiconducting materials and their properties like band gap, cost, mobility, rate of electron injection, and static dielectric constant are considered and MADM technique is applied to select the best suited material. It was found that, out of all possible candidates, titanium dioxide (TiO2 is the best semiconductor material for application in DSC. It was observed that the proposed results are in good agreement with the experimental findings.

  2. Bismuth-doped Cu(In,Ga)Se{sub 2} absorber prepared by multi-layer precursor method and its solar cell

    Chantana, Jakapan; Hironiwa, Daisuke; Minemoto, Takashi [Department of Electrical and Electronic Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Watanabe, Taichi; Teraji, Seiki; Kawamura, Kazunori [Environment and Energy Research Center, Nitto Denko Corporation, 2-8 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2015-06-15

    Bismuth (Bi)-doped Cu(In,Ga)Se{sub 2} (CIGS) films were prepared by the so-called ''multi-layer precursor method'', obtained by depositing them onto Bi layers with various thicknesses on Mo-coated soda-lime glass (SLG) substrates. Material composition (Cu, In, Ga, and Se) profiles of the CIGS films are almost identical, whereas sodium (Na) is reduced, when Bi thickness is increased. Moreover, the incorporation of Bi into the CIGS film is enhanced with thicker Bi layer. With Bi thickness from 0 to 70 nm, the 2.4-μm-thick CIGS absorbers demonstrate the increase in CIGS grain size, carrier lifetime, and carrier concentration, thus improving their cell performances, especially open-circuit voltage (V{sub OC}). With further increase in Bi thickness of above 70 nm, the CIGS films show the deterioration of CIGS film quality owing to the formation of Bi compounds such as Bi, BiSe, and Bi{sub 4}Se{sub 3}. Consequently, Bi-doped CIGS absorber with thickness of 2.4 μm, prepared with the 70-nm-thick Bi layer on Mo-coated SLG substrate, gives rise to the improvement of photovoltaic performances, especially V{sub OC}. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Bismuth-doped Cu(In,Ga)Se2 absorber prepared by multi-layer precursor method and its solar cell

    Chantana, Jakapan; Hironiwa, Daisuke; Minemoto, Takashi; Watanabe, Taichi; Teraji, Seiki; Kawamura, Kazunori

    2015-01-01

    Bismuth (Bi)-doped Cu(In,Ga)Se 2 (CIGS) films were prepared by the so-called ''multi-layer precursor method'', obtained by depositing them onto Bi layers with various thicknesses on Mo-coated soda-lime glass (SLG) substrates. Material composition (Cu, In, Ga, and Se) profiles of the CIGS films are almost identical, whereas sodium (Na) is reduced, when Bi thickness is increased. Moreover, the incorporation of Bi into the CIGS film is enhanced with thicker Bi layer. With Bi thickness from 0 to 70 nm, the 2.4-μm-thick CIGS absorbers demonstrate the increase in CIGS grain size, carrier lifetime, and carrier concentration, thus improving their cell performances, especially open-circuit voltage (V OC ). With further increase in Bi thickness of above 70 nm, the CIGS films show the deterioration of CIGS film quality owing to the formation of Bi compounds such as Bi, BiSe, and Bi 4 Se 3 . Consequently, Bi-doped CIGS absorber with thickness of 2.4 μm, prepared with the 70-nm-thick Bi layer on Mo-coated SLG substrate, gives rise to the improvement of photovoltaic performances, especially V OC . (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. On the use of photothermal techniques for the characterization of solar-selective coatings

    Ramírez-Rincón, J. A.; Ares-Muzio, O.; Macias, J. D.; Estrella-Gutiérrez, M. A.; Lizama-Tzec, F. I.; Oskam, G.; Alvarado-Gil, J. J.

    2018-03-01

    The efficiency of the conversion of solar energy into thermal energy is determined by the optical and thermal properties of the selective coating, in particular, the solar absorptance and thermal emittance at the desired temperature of the specific application. Photothermal techniques are the most appropriate methods to explore these properties, however, a quantitative determination using photothermal radiometry, which is based on the measurement of emitted radiation caused by the heating generated by a modulated light source, has proven to be elusive. In this work, we present experimental results for selective coatings based on electrodeposited black nickel-nickel on both stainless steel and copper substrates, as well as for commercial TiNOX coatings on aluminum, illustrating that the radiation emitted by the surface depends on the optical absorption, thermal emissivity and on the light-into-heat energy conversion efficiency (quantum efficiency). We show that a combination of photothermal radiometry and photoacoustic spectroscopy can successfully account for these parameters, and provide values for the emissivity in agreement with values obtained by Fourier-transform infrared spectroscopy.

  5. Low temperature formation of CuIn{sub 1−x}Ga{sub x}Se{sub 2} solar cell absorbers by all printed multiple species nanoparticulate Se + Cu-In + Cu-Ga precursors

    Möckel, Stefan A., E-mail: Stefan.A.Moeckel@FAU.de [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany); Wernicke, Tobias; Arzig, Matthias; Köder, Philipp [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany); Brandl, Marco [Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 3, 91058 Erlangen (Germany); Ahmad, Rameez; Distaso, Monica; Peukert, Wolfgang [Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen (Germany); Hock, Rainer [Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 3, 91058 Erlangen (Germany); Wellmann, Peter J. [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany)

    2015-05-01

    In this work an all nanoparticulate precursor for application in Cu(In{sub 1−x}Ga{sub x})Se{sub 2} solar cell absorbers is presented. Binary Cu-In nanoparticles, Cu-Ga powder and elemental Se nanoparticles were mixed in dispersion and deposited on Mo-coated substrates. Research was focused on Cu(In{sub 1−x}Ga{sub x})Se{sub 2} layer formation kinetics, phase composition characterised by differential scanning calorimetry and in-situ X-ray diffraction (XRD). Furthermore phase composition and morphology were studied by ex-situ XRD, Raman spectroscopy and scanning electron microscopy. The results revealed a fast consumption of the precursor and the formation of CuInSe{sub 2} below 340 °C. Binary secondary phases were not observed at any temperature. - Highlights: • All printable precursor for CIGSe • Formation of Ga droplets • Complete consumption below 340 °C.

  6. PERFORMANCE EVALUATION OF SOLAR COLLECTORS USING A SOLAR SIMULATOR

    M. Norhafana

    2015-11-01

    Full Text Available Solar water heating systems is one of the applications of solar energy. One of the components of a solar water heating system is a solar collector that consists of an absorber. The performance of the solar water heating system depends on the absorber in the solar collector. In countries with unsuitable weather conditions, the indoor testing of solar collectors with the use of a solar simulator is preferred. Thus, this study is conducted to use a multilayered absorber in the solar collector of a solar water heating system as well as to evaluate the performance of the solar collector in terms of useful heat of the multilayered absorber using the multidirectional ability of a solar simulator at several values of solar radiation. It is operated at three variables of solar radiation of 400 W/m2, 550 W/m2 and 700 W/m2 and using three different positions of angles at 0º, 45º and 90º. The results show that the multilayer absorber in the solar collector is only able to best adapt at 45° of solar simulator with different values of radiation intensity. At this angle the maximum values of useful heat and temperature difference are achieved. KEYWORDS: solar water heating system; solar collector; multilayered absorber; solar simulator; solar radiation 

  7. Low band gap S,N-heteroacene-based oligothiophenes as hole-transporting and light absorbing materials for efficient perovskite-based solar cells

    Qin, Peng

    2014-07-15

    Novel low band gap oligothiophenes incorporating S,N-heteropentacene central units were developed and used as hole-transport materials (HTMs) in solid-state perovskite-based solar cells. In addition to appropriate electronic energy levels, these materials show high photo-absorptivity in the low energy region, and thus can contribute to the light harvesting of the solar spectrum. Solution-processed CH3NH3PbI3-based devices using these HTMs achieved power conversion efficiencies of 9.5-10.5% in comparison with 7.6% obtained by reference devices without HTMs. Photoinduced absorption spectroscopy gave further insight into the charge transfer behavior between photoexcited perovskites and the HTMs. This journal is © the Partner Organisations 2014.

  8. Low band gap S,N-heteroacene-based oligothiophenes as hole-transporting and light absorbing materials for efficient perovskite-based solar cells

    Qin, Peng; Kast, Hannelore; Nazeeruddin, Mohammad K.; Zakeeruddin, Shaik M.; Mishra, Amaresh; Bä uerle, Peter; Grä tzel, Michael

    2014-01-01

    Novel low band gap oligothiophenes incorporating S,N-heteropentacene central units were developed and used as hole-transport materials (HTMs) in solid-state perovskite-based solar cells. In addition to appropriate electronic energy levels, these materials show high photo-absorptivity in the low energy region, and thus can contribute to the light harvesting of the solar spectrum. Solution-processed CH3NH3PbI3-based devices using these HTMs achieved power conversion efficiencies of 9.5-10.5% in comparison with 7.6% obtained by reference devices without HTMs. Photoinduced absorption spectroscopy gave further insight into the charge transfer behavior between photoexcited perovskites and the HTMs. This journal is © the Partner Organisations 2014.

  9. Photoluminescence of polycrystalline CuInS{sub 2} absorber layers and solar cells; Photolumineszenz an polykristallinen CuInS{sub 2}-Absorberschichten und Solarzellen

    Toepper, K.

    1996-12-01

    CuInS{sub 2} is a promising material for the development of high efficiency thin film solar cells. The photoluminescence of CuInS{sub 2} thin films and solar cells is examined in this work. From the recombination of excitons no variation of the band gap with temperature is observed for T{<=}150 K. Samples prepared with excess of indium show strong phonon coupling of a conduction band - acceptor transition (copper vacancy). For samples prepared with excess of copper, a donor acceptor pair recombination is observed (sulphur vacancy as donor and indium vacancy or copper-indium antisite as acceptor). Other samples show a donor acceptor pair recombination at 1.445 eV (sulphur vacancy - copper vacancy). The intensity of this peak increases by more than a factor of 100 due to annealing in hydrogen. Annealing in oxygen reduces the peak again. This phenomenon is reversible and is also observed in the photoluminescence of solar cells. The measurement of hydrogen depth profiles shows that no hydrogen is incorporated by hydrogen annealing. A simple defect model is developed that assumes the occupation of sulphur vacancies by oxygen at grain boundaries. Annealing in hydrogen atmosphere removes oxygen from the vacancies, which are potential states for recombination. Subsequent annealing in oxygen reoccupies the sulphur sites in part thus reducing the intensity of the corresponding peak. (orig.) 83 refs.

  10. Modification of electron states in CdTe absorber due to a buffer layer in CdTe/CdS solar cells

    Fedorenko, Y. G.; Major, J. D.; Pressman, A.; Phillips, L. J.; Durose, K.

    2015-01-01

    By application of the ac admittance spectroscopy method, the defect state energy distributions were determined in CdTe incorporated in thin film solar cell structures concluded on ZnO, ZnSe, and ZnS buffer layers. Together with the Mott-Schottky analysis, the results revealed a strong modification of the defect density of states and the concentration of the uncompensated acceptors as influenced by the choice of the buffer layer. In the solar cells formed on ZnSe and ZnS, the Fermi level and the energy position of the dominant deep trap levels were observed to shift closer to the midgap of CdTe, suggesting the mid-gap states may act as recombination centers and impact the open-circuit voltage and the fill factor of the solar cells. For the deeper states, the broadening parameter was observed to increase, indicating fluctuations of the charge on a microscopic scale. Such changes can be attributed to the grain-boundary strain and the modification of the charge trapped at the grain-boundary interface states in polycrystalline CdTe

  11. Modification of electron states in CdTe absorber due to a buffer layer in CdTe/CdS solar cells

    Fedorenko, Y. G., E-mail: y.fedorenko@liverpool.ac.uk; Major, J. D.; Pressman, A.; Phillips, L. J.; Durose, K. [Stephenson Institute for Renewable Energy and Department of Physics, School of Physical Sciences, Chadwick Building, University of Liverpool, Liverpool L69 7ZF (United Kingdom)

    2015-10-28

    By application of the ac admittance spectroscopy method, the defect state energy distributions were determined in CdTe incorporated in thin film solar cell structures concluded on ZnO, ZnSe, and ZnS buffer layers. Together with the Mott-Schottky analysis, the results revealed a strong modification of the defect density of states and the concentration of the uncompensated acceptors as influenced by the choice of the buffer layer. In the solar cells formed on ZnSe and ZnS, the Fermi level and the energy position of the dominant deep trap levels were observed to shift closer to the midgap of CdTe, suggesting the mid-gap states may act as recombination centers and impact the open-circuit voltage and the fill factor of the solar cells. For the deeper states, the broadening parameter was observed to increase, indicating fluctuations of the charge on a microscopic scale. Such changes can be attributed to the grain-boundary strain and the modification of the charge trapped at the grain-boundary interface states in polycrystalline CdTe.

  12. High-Temperature High-Efficiency Solar Thermoelectric Generators

    Baranowski, LL; Warren, EL; Toberer, ES

    2014-03-01

    Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000A degrees C to 100A degrees C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

  13. Dopant-Free and Carrier-Selective Heterocontacts for Silicon Solar Cells: Recent Advances and Perspectives.

    Gao, Pingqi; Yang, Zhenhai; He, Jian; Yu, Jing; Liu, Peipei; Zhu, Juye; Ge, Ziyi; Ye, Jichun

    2018-03-01

    By combining the most successful heterojunctions (HJ) with interdigitated back contacts, crystalline silicon (c-Si) solar cells (SCs) have recently demonstrated a record efficiency of 26.6%. However, such SCs still introduce optical/electrical losses and technological issues due to parasitic absorption/Auger recombination inherent to the doped films and the complex process of integrating discrete p + - and n + -HJ contacts. These issues have motivated the search for alternative new functional materials and simplified deposition technologies, whereby carrier-selective contacts (CSCs) can be formed directly with c-Si substrates, and thereafter form IBC cells, via a dopant-free method. Screening and modifying CSC materials in a wider context is beneficial for building dopant-free HJ contacts with better performance, shedding new light on the relatively mature Si photovoltaic field. In this review, a significant number of achievements in two representative dopant-free hole-selective CSCs, i.e . , poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate)/Si and transition metal oxides/Si, have been systemically presented and surveyed. The focus herein is on the latest advances in hole-selective materials modification, interfacial passivation, contact resistivity, light-trapping structure and device architecture design, etc. By analyzing the structure-property relationships of hole-selective materials and assessing their electrical transport properties, promising functional materials as well as important design concepts for such CSCs toward high-performance SCs have been highlighted.

  14. Dopant‐Free and Carrier‐Selective Heterocontacts for Silicon Solar Cells: Recent Advances and Perspectives

    Yang, Zhenhai; He, Jian; Yu, Jing; Liu, Peipei; Zhu, Juye; Ge, Ziyi; Ye, Jichun

    2017-01-01

    Abstract By combining the most successful heterojunctions (HJ) with interdigitated back contacts, crystalline silicon (c‐Si) solar cells (SCs) have recently demonstrated a record efficiency of 26.6%. However, such SCs still introduce optical/electrical losses and technological issues due to parasitic absorption/Auger recombination inherent to the doped films and the complex process of integrating discrete p+‐ and n+‐HJ contacts. These issues have motivated the search for alternative new functional materials and simplified deposition technologies, whereby carrier‐selective contacts (CSCs) can be formed directly with c‐Si substrates, and thereafter form IBC cells, via a dopant‐free method. Screening and modifying CSC materials in a wider context is beneficial for building dopant‐free HJ contacts with better performance, shedding new light on the relatively mature Si photovoltaic field. In this review, a significant number of achievements in two representative dopant‐free hole‐selective CSCs, i.e., poly(3,4‐ethylene dioxythiophene):poly(styrenesulfonate)/Si and transition metal oxides/Si, have been systemically presented and surveyed. The focus herein is on the latest advances in hole‐selective materials modification, interfacial passivation, contact resistivity, light‐trapping structure and device architecture design, etc. By analyzing the structure–property relationships of hole‐selective materials and assessing their electrical transport properties, promising functional materials as well as important design concepts for such CSCs toward high‐performance SCs have been highlighted. PMID:29593956

  15. Cobalt oxide films for solar selective surfaces, obtained by spray pyrolisis

    Avila G, A. [Departmento de Ingenieria Electrica, Seccion de Electronica del Estado Solido, CINVESTAV del I.P.N., Av. I.P.N. no. 2508, Ap. Postal 14-740, Mexico D. F., 07360 (Mexico); Barrera C, E. [Departamento de IPH, Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Ap. Postal 55-5340, Mexico, D. F. (Mexico); Huerta A, L.; Muhl, S. [Instituto de Investigaciones en Materiales, UNAM, Mexico, D.F. 04510 (Mexico)

    2004-05-01

    Cobalt oxide films upon stainless steel substrates were deposited by using the pneumatic spray pyrolisis technique, starting from an inorganic salt (CoNO{sub 3}{center_dot}3H{sub 2}O) dissolved in a water-alcohol mixture. Stainless steel and nickeled stainless steel substrates were used. Absorptance and emittance, for selective surface applications, were evaluated from reflectance measurements in the UV-Vis and infrared ranges. X-ray diffraction, XPS and AFM measurements were done. The predominant cobalt phase is Co{sub 3}O{sub 4}, but also CoO and Co{sub 2}O{sub 3} phases, besides metallic cobalt, were detected. Films upon nickeled steel substrates at 400C exhibit high absorptances (0.86), but also the emittance is high (0.43), yielding a selectivity of 2.0. A similar film on steel substrate reaches only a figure of 0.77 absorptance, but the thermal emittance remains low (0.20), giving a selectivity of 3.85. These films are good prospects for selective solar absorption coatings.

  16. The crystallisation of Cu2ZnSnS4 thin film solar cell absorbers from co-electroplated Cu-Zn-Sn precursors

    Schurr, R.; Hoelzing, A.; Jost, S.; Hock, R.; Voss, T.; Schulze, J.; Kirbs, A.; Ennaoui, A.; Lux-Steiner, M.; Weber, A.; Koetschau, I.; Schock, H.-W.

    2009-01-01

    The best CZTS solar cell so far was produced by co-sputtering continued with vapour phase sulfurization method. Efficiencies of up to 5.74% were reached by Katagiri et al. The one step electrochemical deposition of copper, zinc, tin and subsequent sulfurization is an alternative fabrication technique for the production of Cu 2 ZnSnS 4 based thin film solar cells. A kesterite based solar cell (size 0.5 cm 2 ) with a conversion efficiency of 3.4% (AM1.5) was produced by vapour phase sulfurization of co-electroplated Cu-Zn-Sn films. We report on results of in-situ X-ray diffraction (XRD) experiments during crystallisation of kesterite thin films from electrochemically co-deposited metal films. The kesterite crystallisation is completed by the solid state reaction of Cu 2 SnS 3 and ZnS. The measurements show two different reaction paths depending on the metal ratios in the as deposited films. In copper-rich metal films Cu 3 Sn and CuZn were found after electrodeposition. In copper-poor or near stoichiometric precursors additional Cu 6 Sn 5 and Sn phases were detected. The formation mechanism of Cu 2 SnS 3 involves the binary sulphides Cu 2-x S and SnS 2 in the absence of the binary precursor phase Cu 6 Sn 5 . The presence of Cu 6 Sn 5 leads to a preferred formation of Cu 2 SnS 3 via the reaction educts Cu 2-x S and SnS 2 in the presence of a SnS 2 (Cu 4 SnS 6 ) melt. The melt phase may be advantageous in crystallising the kesterite, leading to enhanced grain growth in the presence of a liquid phase

  17. Intermixing at the heterointerface between ZnS Zn S,O bilayer buffer and CuInS2 thin film solar cell absorber

    Bär, M.; Ennaoui, A.; Klaer, J.; Kropp, T.; S ez Araoz, R.; Lehmann, S.; Grimm, A.; Lauermann, I.; Loreck, Ch.; Sokoll, St.; Schock, H. W.; Fischer, Ch. H.; Lux Steiner, M.C.; Jung, Ch

    2006-01-01

    The application of Zn compounds as buffer layers was recently extended to wide gap CuInS2 CIS based thin film solar cells. Using a new chemical deposition route for the buffer preparation aiming at the deposition of a single layer, nominal ZnS buffer without the need for any toxic reactants such as, e.g. hydrazine has helped to achieve a similar efficiency as respective CdS buffered reference devices. After identifying the deposited Zn compound, as ZnS Zn S,O bi layer buffer in former in...

  18. Formation of a ZnS Zn S,O bilayer buffer on CuInS2 thin film solar cell absorbers by chemical bath deposition

    Bär, M.; Ennaoui, A.; Klaer, J.; Kropp, T.; S ez Araoz, R.; Allsop, N.; Lauermann, I.; Schock, H. W.; Lux Steiner, M.C

    2006-01-01

    The application of Zn compounds as buffer layers was recently extended to wide gap CuInS2 CIS based thin film solar cells. Using a new chemical deposition route for the buffer preparation aiming at the deposition of a single layer, nominal ZnS buffer without the need for any toxic reactants such as, e.g. hydrazine, has helped to achieve a similar efficiency as respective CdS buffered reference devices. In order to shed light on the differences of other Zn compound buffers deposited in con...

  19. Effect of accelerated thermal ageing on the selective solar thermal harvesting properties of multiwall carbon nanotube/nickel oxide nanocomposite coatings

    Roro, Kittessa T

    2012-05-01

    Full Text Available Varying amounts of dispersed multiwalled carbon nanotubes in NiO have been used to develop composites that absorb the solar energy very well but lose very little through emission. Determination of absorptance, asol, and emissivity, ether, from...

  20. Solar Energy Technician/Installer

    Moore, Pam

    2007-01-01

    Solar power (also known as solar energy) is solar radiation emitted from the sun. Large panels that absorb the sun's energy as the sun beats down on them gather solar power. The energy in the rays can be used for heat (solar thermal energy) or converted to electricity (photovoltaic energy). Each solar energy project, from conception to…

  1. Performance Improvements of Selective Emitters by Laser Openings on Large-Area Multicrystalline Si Solar Cells

    Sheng-Shih Wang

    2014-01-01

    Full Text Available This study focuses on the laser opening technique used to form a selective emitter (SE structure on multicrystalline silicon (mc-Si. This technique can be used in the large-area (156 × 156 mm2 solar cells. SE process of this investigation was performed using 3 samples SE1–SE3. Laser fluences can vary in range of 2–5 J/cm2. The optimal conversion efficiency of 15.95% is obtained with the SE3 (2 J/cm2 fluence after laser opening with optimization of heavy and light dopant, which yields a gain of 0.48%abs compared with that of a reference cell (without fluence. In addition, this optimal SE3 cell displays improved characteristics compared with other cells with a higher average value of external quantum efficiency (EQEavg = 68.6% and a lower average value of power loss (Ploss = 2.33 mW/cm2. For the fabrication of solar cells, the laser opening process comprises fewer steps than traditional photolithography does. Furthermore, the laser opening process decreases consumption of chemical materials; therefore, the laser opening process decreases both time and cost. Therefore, SE process is simple, cheap, and suitable for commercialization. Moreover, the prominent features of the process render it effective means to promote overall performance in the photovoltaic industry.

  2. Design and measured performance of a solar chimney for natural-circulation solar-energy dryers

    Ekechukwu, O.V.; Norton, B.

    1995-10-01

    The design and construction of a solar chimney which was undertaken as part of a study on natural-circulation solar-energy dryers is reported. The experimental solar chimney consists of a 5.3m high and 1.64m diameter cylindrical polyethylene-clad vertical chamber, supported structurally by steel framework and draped internally with a selectively-absorbing surface. The performance of the chimney which was monitored extensively with and without the selective surface in place (to study the effectiveness of this design option) is also reported. (author). 14 refs, 7 figs

  3. Consumer preferences for selection of solar home system in urban areas, pakistan

    Gohar, K.

    2014-01-01

    Consumer preferences can lay foundation for determining key product attributes essential for the success of a product in the market, enabling the manufacturers optimally allocate resources towards imparting these critical attributes. However identification of consumer preferences especially for new products is a challenging task. This research investigated the consumer preference factors for solar home systems in Rawalpindi/Islamabad (Pakistan); applying MCDM (Multi Criteria Decision Making) approach, AHP (Analytical Hierarchy Process) survey and analysis method is used for prioritization of the factors and comparison of decision alternatives. Fourteen factors grouped into five categories are selected. It has been found that the manufacturers have to emphasize on performance and functional attributes of these systems at this stage, the cost factors are comparatively lower in importance. Make and warranty, Environmental and Physical features are also lesser important to the early adopters. (author)

  4. Core–shell-typed Ag-SiO2 nanoparticles as solar selective coating materials

    Gao, Tao; Jelle, Bjørn Petter; Gustavsen, Arild

    2013-01-01

    Silver (Ag) nanoparticles with typical diameter of about 50 nm have been prepared via a polyol process. The as-prepared Ag nanoparticles are well crystallized and exhibit a characteristic surface plasmon resonance (SPR) band centered at ∼423 nm. The SPR band shows a strong dependence on the sizes of Ag nanoparticles and the types of the dielectric medium. Core–shell-typed Ag-SiO 2 nanoparticles have also been prepared by depositing a thin layer (∼25 nm) of silica on Ag nanoparticles. The core–shell-typed Ag-SiO 2 nanoparticles show similar optical behaviors (absorption, transmission, and reflection) but enhanced stability compared to those of the Ag nanoparticles, indicating that the core–shell-typed Ag-SiO 2 nanoparticles may be used as solar selective coating materials for architectural window applications.

  5. The crystallisation of Cu{sub 2}ZnSnS{sub 4} thin film solar cell absorbers from co-electroplated Cu-Zn-Sn precursors

    Schurr, R. [Chair for Crystallography and Structural Physics, University of Erlangen-Nuernberg, Staudtstrasse 3, D-91058 Erlangen (Germany)], E-mail: schurr@krist.uni-erlangen.de; Hoelzing, A.; Jost, S.; Hock, R. [Chair for Crystallography and Structural Physics, University of Erlangen-Nuernberg, Staudtstrasse 3, D-91058 Erlangen (Germany); Voss, T.; Schulze, J.; Kirbs, A. [Atotech Deutschland GmbH, Erasmusstrasse 20, D-10553 Berlin (Germany); Ennaoui, A.; Lux-Steiner, M. [Heterogeneous Material Systems SE II, Hahn-Meitner-Institut, Glienickerstr.100, D-14109 Berlin (Germany); Weber, A.; Koetschau, I.; Schock, H.-W. [Technology SE III, Hahn-Meitner-Institut, Glienickerstr.100, D-14109 Berlin (Germany)

    2009-02-02

    The best CZTS solar cell so far was produced by co-sputtering continued with vapour phase sulfurization method. Efficiencies of up to 5.74% were reached by Katagiri et al. The one step electrochemical deposition of copper, zinc, tin and subsequent sulfurization is an alternative fabrication technique for the production of Cu{sub 2}ZnSnS{sub 4} based thin film solar cells. A kesterite based solar cell (size 0.5 cm{sup 2}) with a conversion efficiency of 3.4% (AM1.5) was produced by vapour phase sulfurization of co-electroplated Cu-Zn-Sn films. We report on results of in-situ X-ray diffraction (XRD) experiments during crystallisation of kesterite thin films from electrochemically co-deposited metal films. The kesterite crystallisation is completed by the solid state reaction of Cu{sub 2}SnS{sub 3} and ZnS. The measurements show two different reaction paths depending on the metal ratios in the as deposited films. In copper-rich metal films Cu{sub 3}Sn and CuZn were found after electrodeposition. In copper-poor or near stoichiometric precursors additional Cu{sub 6}Sn{sub 5} and Sn phases were detected. The formation mechanism of Cu{sub 2}SnS{sub 3} involves the binary sulphides Cu{sub 2-x}S and SnS{sub 2} in the absence of the binary precursor phase Cu{sub 6}Sn{sub 5}. The presence of Cu{sub 6}Sn{sub 5} leads to a preferred formation of Cu{sub 2}SnS{sub 3} via the reaction educts Cu{sub 2-x}S and SnS{sub 2} in the presence of a SnS{sub 2}(Cu{sub 4}SnS{sub 6}) melt. The melt phase may be advantageous in crystallising the kesterite, leading to enhanced grain growth in the presence of a liquid phase.

  6. Enhancing the Durability and Carrier Selectivity of Perovskite Solar Cells Using a Blend Interlayer.

    Sin, Dong Hun; Jo, Sae Byeok; Lee, Seung Goo; Ko, Hyomin; Kim, Min; Lee, Hansol; Cho, Kilwon

    2017-05-31

    A mechanically and thermally stable and electron-selective ZnO/CH 3 NH 3 PbI 3 interface is created via hybridization of a polar insulating polymer, poly(ethylene glycol) (PEG), into ZnO nanoparticles (NPs). PEG successfully passivates the oxygen defects on ZnO and prevents direct contact between CH 3 NH 3 PbI 3 and defects on ZnO. A uniform CH 3 NH 3 PbI 3 film is formed on a soft ZnO:PEG layer after dispersion of the residual stress from the volume expansion during CH 3 NH 3 PbI 3 conversion. PEG also increases the work of adhesion of the CH 3 NH 3 PbI 3 film on the ZnO:PEG layer and holds the CH 3 NH 3 PbI 3 film with hydrogen bonding. Furthermore, PEG tailors the interfacial electronic structure of ZnO, reducing the electron affinity of ZnO. As a result, a selective electron-collection cathode is formed with a reduced electron affinity and a deep-lying valence band of ZnO, which significantly enhances the carrier lifetime (473 μs) and photovoltaic performance (15.5%). The mechanically and electrically durable ZnO:PEG/CH 3 NH 3 PbI 3 interface maintains the sustainable performance of the solar cells over 1 year. A soft and durable cathodic interface via PEG hybridization in a ZnO layer is an effective strategy toward flexible electronics and commercialization of the perovskite solar cells.

  7. Selective ablation of Copper-Indium-Diselenide solar cells monitored by laser-induced breakdown spectroscopy and classification methods

    Diego-Vallejo, David [Technische Universität Berlin, Institute of Optics and Atomic Physics, Straße des 17, Juni 135, 10623 Berlin (Germany); Laser- und Medizin- Technologie Berlin GmbH (LMTB), Applied Laser Technology, Fabeckstr. 60-62, 14195 Berlin (Germany); Ashkenasi, David, E-mail: d.ashkenasi@lmtb.de [Laser- und Medizin- Technologie Berlin GmbH (LMTB), Applied Laser Technology, Fabeckstr. 60-62, 14195 Berlin (Germany); Lemke, Andreas [Laser- und Medizin- Technologie Berlin GmbH (LMTB), Applied Laser Technology, Fabeckstr. 60-62, 14195 Berlin (Germany); Eichler, Hans Joachim [Technische Universität Berlin, Institute of Optics and Atomic Physics, Straße des 17, Juni 135, 10623 Berlin (Germany); Laser- und Medizin- Technologie Berlin GmbH (LMTB), Applied Laser Technology, Fabeckstr. 60-62, 14195 Berlin (Germany)

    2013-09-01

    Laser-induced breakdown spectroscopy (LIBS) and two classification methods, i.e. linear correlation and artificial neural networks (ANN), are used to monitor P1, P2 and P3 scribing steps of Copper-Indium-Diselenide (CIS) solar cells. Narrow channels featuring complete removal of desired layers with minimum damage on the underlying film are expected to enhance efficiency of solar cells. The monitoring technique is intended to determine that enough material has been removed to reach the desired layer based on the analysis of plasma emission acquired during multiple pass laser scribing. When successful selective scribing is achieved, a high degree of similarity between test and reference spectra has to be identified by classification methods in order to stop the scribing procedure and avoid damaging the bottom layer. Performance of linear correlation and artificial neural networks is compared and evaluated for two spectral bandwidths. By using experimentally determined combinations of classifier and analyzed spectral band for each step, classification performance achieves errors of 7, 1 and 4% for steps P1, P2 and P3, respectively. The feasibility of using plasma emission for the supervision of processing steps of solar cell manufacturing is demonstrated. This method has the potential to be implemented as an online monitoring procedure assisting the production of solar cells. - Highlights: • LIBS and two classification methods were used to monitor CIS solar cells processing. • Selective ablation of thin-film solar cells was improved with inspection system. • Customized classification method and analyzed spectral band enhanced performance.

  8. Purchase aspects playing a part in the broad selection of solar boiler types

    Van Amerongen, G.A.H.

    1996-01-01

    Because of the large variety of solar water heaters in the Netherlands and abroad the arguments to purchase such boilers have to be reconsidered. In this article a few practical guidelines are given, focusing on solar boilers equipped with thermosyphon collector circuits or enamel steel storage tanks, and some typical aspects of imported solar water heaters. 3 figs., 1 tab., 1 refs

  9. Shock absorbing structure

    Kojima, Naoki; Matsushita, Kazuo.

    1992-01-01

    Small pieces of shock absorbers are filled in a space of a shock absorbing vessel which is divided into a plurality of sections by partitioning members. These sections function to prevent excess deformation or replacement of the fillers upon occurrence of falling accident. Since the shock absorbing small pieces in the shock absorbing vessel are filled irregularly, shock absorbing characteristics such as compression strength is not varied depending on the direction, but they exhibit excellent shock absorbing performance. They surely absorb shocks exerted on a transportation vessel upon falling or the like. If existing artificial fillers such as pole rings made of metal or ceramic and cut pieces such as alumium extrusion molding products are used as the shock absorbing pieces, they have excellent fire-proofness and cold resistance since the small pieces are inflammable and do not contain water. (T.M.)

  10. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se2 thin-film solar cell absorbers

    Lehmann, Jascha; Lehmann, Sebastian; Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch.; Bär, Marcus; Sadewasser, Sascha

    2014-12-01

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for "realistic" surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In1-xGax)Se2 thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH3-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is - apart from a slight change in surface composition - identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  11. One-step fabrication of novel superhydrophobic and superoleophilic sponge with outstanding absorbency and flame-retardancy for the selective removal of oily organic solvent from water

    Xiang, Yuqian; Pang, Youyou; Jiang, Xiaomei; Huang, Jie; Xi, Fengna; Liu, Jiyang

    2018-01-01

    Absorbent materials integrated with superhydrophobicity, superoleophilicity and flame-retardancy are highly desired in the adsorption/removal of flammable oils/organic compounds as well as reducing the risk of fire and explosion. Here, one-step fabrication of novel superhydrophobic and superoleophilic sponge with outstanding absorbency and flame-retardancy was presented. Using raw melamine (ME) sponge as the supporting matrix, the formation of polydopamine (PDA) nanoaggregates via in-situ self-polymerization of high-concentrated dopamine and the covalent grafting of hydrophobic n-dodecylthiol (DT) onto PDA were combined in a feasible alkaline water/ethanol medium. As investigated by scanning electron microscopy (SEM) and X-ray energy-dispersive spectroscopy (EDS), the as-prepared ME/PDA/DT sponge possessed hierarchical structure with submicron PDA nanoaggregates containing DT motif (low surface energy) on 3D interconnected porous network. It exhibited superhydrophobic (water contact angle 157.7°) and superoleophilic (oily/organic solvent contact angle 0° properties. Owing to the highly porous structure, superhydrophobic property, chemical and mechanical stability, the ME/PDA/DT sponge exhibited outstanding absorbency properties of oily organic solvents including fast absorption kinetics, high absorption capacity, and easy reusability. Also, the ME/PDA/DT sponge could be used for one-line continuous organic solvent/water separation. More interestingly, the ME/PDA/DT sponge demonstrated improved flame-retardant property as compared to the intrinsic flame-retardant nature of the raw melamine sponge. Consequently, the risk of fire and explosion was expected to reduce when the fabricated sponge was used as an absorbent for flammable oils and organic compounds. The ease of the one-step superhydrophobic/superoleophilic modification and the promising feature of the obtained materials exhibit great potential for application in oils/organic solvents clean-up.

  12. An ANP-based approach for the selection of photovoltaic solar power plant investment projects

    Aragones-Beltran, P.; Pastor-Ferrando, J.P.; Rodriguez-Pozo, F.; Chaparro-Gonzalez, F.

    2010-01-01

    In this paper the Analytic Network Process (ANP) is applied to the selection of photovoltaic (PV) solar power projects. These projects follow a long management and execution process from plant site selection to plant start-up. As a consequence, there are many risks of time delays and even of project stoppage. In the case study presented in this paper a top manager of an important Spanish company that operates in the power market has to decide on the best PV project (from four alternative projects) to invest based on risk minimization. The manager identified 50 project execution delay and/or stoppage risks. The influences between the elements of the network (groups of risks and alternatives) were identified and analyzed using the ANP multicriteria decision analysis method. Two different ANP models were used: one hierarchy model (that considers AHP as a particular case of ANP) and one network-based model. The results obtained in each model were compared and analyzed. The main conclusion is that unlike the other models used in the study, the single network model can manage all the information of the real-world problem and thus it is the decision analysis model recommended by the authors. The strengths and weaknesses of ANP as a multicriteria decision analysis tool are also described in the paper. (author)

  13. Metamaterial electromagnetic wave absorbers.

    Watts, Claire M; Liu, Xianliang; Padilla, Willie J

    2012-06-19

    The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Adaptive inertial shock-absorber

    Faraj, Rami; Holnicki-Szulc, Jan; Knap, Lech; Seńko, Jarosław

    2016-01-01

    This paper introduces and discusses a new concept of impact absorption by means of impact energy management and storage in dedicated rotating inertial discs. The effectiveness of the concept is demonstrated in a selected case-study involving spinning management, a recently developed novel impact-absorber. A specific control technique performed on this device is demonstrated to be the main source of significant improvement in the overall efficiency of impact damping process. The influence of various parameters on the performance of the shock-absorber is investigated. Design and manufacturing challenges and directions of further research are formulated. (paper)

  15. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se{sub 2} thin-film solar cell absorbers

    Lehmann, Jascha [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Potsdam Institute for Climate Impact Research (PIK), 14473 Potsdam (Germany); Lehmann, Sebastian, E-mail: sebastian.lehmann@ftf.lth.se [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Solid State Physics, Lund University, Box 118, S-22100 Lund (Sweden); Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch. [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Bär, Marcus, E-mail: marcus.baer@helmholtz-berlin.de [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg, Platz der Deutschen Einheit 1, 03046 Cottbus (Germany); Sadewasser, Sascha, E-mail: sascha.sadewasser@inl.int [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga (Portugal)

    2014-12-21

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for “realistic” surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In{sub 1-x}Ga{sub x})Se{sub 2} thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH{sub 3}-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is – apart from a slight change in surface composition – identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  16. Socio-technical assessment of solar photovoltaic systems implemented for rural electrification in selected villages of Sundarbans region of India

    Rashmi Murali

    2015-10-01

    Full Text Available The power situation in rural India continues to remain poor with around one-third of the rural population without access to any form of electricity. The consequence of which is kerosene being used as a major source of lighting for un-electrified households as well as households with intermittent access to electricity in rural areas. While grid based electrification has been the most common approach, decentralized renewable energy options especially, solar PV systems have also been adopted as a cost effective mode of electrification. This paper presents the results of socio-technical assessment of solar photovoltaic interventions namely, solar home systems, solar mini-grid and solar AC pico-grids, which have been used to electrify selected villages in Sundarbans region of India. The study is focused on technical, financial, and institutional aspects along with the social impact assessment of PV based electrification in the Sundarbans region. The results of the study elucidate that, in general, the impacts of the solar PV solutions used for electrification have been largely positive, especially benefits of reduced kerosene consumption, ease in studying and cooking and reduced health effects. The study also finds that technology is not the only factor on which the viability of a program depends, but institutional and financial aspects also play a significant role. The need of the hour is to develop a strong institutional framework and enabling policies for achieving higher success rates in PV programs.

  17. Novel and conventional working fluid mixtures for solar Rankine cycles: Performance assessment and multi-criteria selection

    Mavrou, Paschalia; Papadopoulos, Athanasios I.; Stijepovic, Mirko Z.; Seferlis, Panos; Linke, Patrick; Voutetakis, Spyros

    2015-01-01

    This work investigates the performance of working fluid mixtures for use in solar ORC (Organic Rankine Cycle systems) with heat storage employing FPC (Flat Plate Collectors). Several mixtures are considered including conventional choices often utilized in ORC as well as novel mixtures previously designed using advanced computer aided molecular design methods (Papadopoulos et al., 2013). The impact of heat source variability on the ORC performance is assessed for different working fluid mixtures. Solar radiation is represented in detail through actual, hourly averaged data for an entire year. A multi-criteria mixture selection methodology unveils important trade-offs among several important system operating parameters and efficiently highlights optimum operating ranges. Such parameters include the ORC thermal efficiency, the net generated power, the volume ratio across the turbine, the mass flow rate of the ORC working fluid, the evaporator temperature glide, the temperature drop in the storage tank, the ORC total yearly operating duration, the required collector aperture area to generate 1 kW of power and the irreversibility. A mixture of neopentane – 2-fluoromethoxy-2-methylpropane at 70% neopentane is found to be the most efficient in all the considered criteria simultaneously. - Highlights: • Investigation of novel and conventional working fluid mixtures for solar ORCs. • Systematic, multi-criteria assessment methodology for mixture selection. • Simultaneous consideration of multiple important mixture performance criteria. • Effects of year-round solar variability in a solar ORC with heat storage tank

  18. Optical properties and thermal stability of TiAlN/AlON tandem absorber prepared by reactive DC/RF magnetron sputtering

    Barshilia, Harish C.; Selvakumar, N.; Rajam, K.S. [Surface Engineering Division, National Aerospace Laboratories, Bangalore 560 017 (India); Biswas, A. [Spectroscopy Division, Bhabha Atomic Research Center, Mumbai 400 085 (India)

    2008-11-15

    Spectrally selective TiAlN/AlON tandem absorbers were deposited on copper and stainless steel substrates using a reactive DC/RF magnetron sputtering system. The compositions and thicknesses of the individual component layers were optimized to achieve high absorptance ({alpha}=0.931-0.942) and low emittance ({epsilon}=0.05-0.06) on copper substrate. The experimental spectroscopic ellipsometric data have been fitted with the theoretical models to derive the dispersion of the optical constants (n and k). In order to study the thermal stability of the tandem absorbers, they were subjected to heat treatment (in air and vacuum) for different durations and temperatures. The tandem absorber deposited on Cu substrates exhibited high solar selectivity ({alpha}/{epsilon}) of 0.946/0.07 even after heat treatment in air up to 600 C for 2 h. At 625 C, the solar selectivity decreased significantly on Cu substrates (e.g., {alpha}/{epsilon}=0.924/0.30). The tandem absorber on Cu substrates was also stable in air up to 100 h at 400 C with a solar selectivity of 0.919/0.06. Studies on the accelerated aging tests indicated that the activation energy for the degradation of the tandem absorber is of the order of 100 kJ/mol. (author)

  19. History of Spanish Selection of the International Solar Energy; Historia de la Asociacion Espanola de Energia solar

    Vazquez, M.

    2004-07-01

    This paper is about the old and new Spanish Sections of the International Solar Energy Society (ISES). The old Section was formed on the initiative of the Spanish Association Atecyr and was named ISES Espana. As a legal Spanish association, it developed its activities from 1981 until 1991 when economic difficulties made ISES suspend the Section. In that year Prof. Manuel Vazquez, director of the Laboratory of Solar Energy of the University of Vigo, became interested in the subject and participated in his restlessness to other Spanish members of ISES. All of them agreed to create a new Spanish association under the name of Asociacion Espanola de Energia Solar (AEDES), which was registered as an ONG in the Spanish National Register of Associations and ratified by ISES as its Spanish Section in 1993. In this paper the significant data of the old and new sections are given, including the names of representative people and members of the Board and the development of the membership. (Author)

  20. GaSe:Cd semiconductor - own oxide nanolamellar structures as a selective gas absorber; Structuri nanolamelare semiconductor GaSe:Cd - oxid propriu ca adsorbant selectiv de gaze

    Dmitroglo, Liliana; Evtodiev, Igor; Lazar, Gheorghe [Univ. de Stat din Moldova, Chisinau (Moldova, Republic of); Caraman, Iuliana [Univ. ' Vasile Alecsandri' din Bacau, Bacau (Romania); Dafinei, Adrian [Universitatea din Bucuresti, Bucuresti (Romania)

    2012-07-15

    A lamella with the thickness of 10-300 {mu}m and C6 axis oriented perpendicular to (001) surface were obtained from {epsilon}-GaSe single crystals grown by Bridgman method. By a heat treatment at the temperature of 450-580 degrees Celsius the lamella surfaces were coated with the own nanostructured (Ga{sub 2}O{sub 3}) oxide. The absorption of polar molecules from the (H{sub 2}O, CO, CON) atmosphere was studied by using absorptional IR spectroscopy. These molecules absorption bands and optical transparency dependence on the absorbed molecules concentration were determined. (authors)

  1. Absorbance and fluorescence studies on porphyrin Nanostructures ...

    The aim of this work was to study some photophysical properties of PNR for application as light harvester in dye sensitized solar cells. These properties included absorbance, fluorescence, and fluorescence quantum yield and lifetime. The results of Transmission Electron Microscope (TEM) images showed the formation of ...

  2. Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

    Ali, Haider

    2017-08-15

    In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21.6% obtained on n-type cells, featuring SiO2/TiO2/Al rear contacts and after forming gas annealing (FGA) at 350°C, is due to strong surface passivation of SiO2/TiO2 stack as well as low contact resistivity at the Si/SiO2/TiO2 heterojunction. This can be attributed to the transformation of amorphous TiO2 to a conducting TiO2-x phase. Conversely, the low efficiency (9.8%) obtained on cells featuring an a-Si:H/TiO2/Al rear contact is due to severe degradation of passivation of the a-Si:H upon FGA.

  3. Methods for absorbing neutrons

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  4. Sunspot variation and selected associated phenomena: a look at solar cycle 21 and beyond

    Wilson, R.M.

    1982-02-01

    Solar sunspot cycles 8 through 21 are reviewed. Mean time intervals are calculated for maximum to maximum, minimum to minimum, minimum to maximum, and maximum to minimum phases for cycles 8 through 20 and 8 through 21. Simple cosine functions with a period of 132 years are compared to, and found to be representative of, the variation of smoothed sunspot numbers at solar maximum and minimum. A comparison of cycles 20 and 21 is given, leading to a projection for activity levels during the Spacelab 2 era (tentatively, November 1984). A prediction is made for cycle 22. Major flares are observed to peak several months subsequent to the solar maximum during cycle 21 and to be at minimum level several months after the solar minimum. Additional remarks are given for flares, gradual rise and fall radio events and 2800 MHz radio emission. Certain solar activity parameters, especially as they relate to the near term Spacelab 2 time frame are estimated

  5. Technical developments of solar energy collectors in the Netherlands

    Oversloot, H.P.; Geus, A.C. de

    1996-01-01

    Recent research by TNO covered two different technical developments for thermal solar energy systems. One concerns a feasibility study into an all plastic spectral selective absorber, the other is a feasibility study for an overheating protection device based on heatpipe techniques. Earlier studies

  6. Quantum-Tuned Two-Junction Solar Cells

    Wang, Xihua

    2011-01-01

    We report quantum-size-effect tuned tandem solar cells. Our two-junction photovoltaic devices employ light-absorbing material of a single composition and use two rationally-selected nanoparticle sizes to harvest the sun’s broad spectrum.

  7. Heat jettisoning from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water; Waermeabwurf aus einer solarthermisch getriebenen LiBr- H{sub 2}O Absorptionskaeltemaschine durch gepulstes Bespruehen eines Trockenkuehlers mit Wasser

    Gantenbein, P.; Helfenberger, R.; Frank, E.

    2010-07-01

    This short, illustrated final report discusses the removal of heat from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water. The reduction of electricity consumption for room cooling using conventional chillers is examined. Heat dissipation using open cooling towers and the disadvantages encountered are compared with heat dissipation using a dry cooler with heat-exchanger and fans. Additional evaporation cooling achieved by spraying the heat exchanger with water is described and discussed. The results of measurements made at the Institute for Solar Technology in Rapperswil, Switzerland, are presented and discussed.

  8. Characterization of Cr-O cermet solar selective coatings deposited by using direct-current magnetron sputtering technology

    Lee, Kil Dong

    2006-01-01

    Cr-O (Cr-CrO) cermet solar selective coatings with a double cermet layer film structure were prepared by using a special direct-current (dc) magnetron sputtering technology. The typical film structure from the surface to the bottom substrate was an Al 2 O 3 anti-reflection layer on a double Cr-O cermet layer on an Al metal infrared reflection layer. The deposited Cr-O cermet solar selective coating had an absorptance of α = 0.93 - 0.95 and an emittance of ε = 0.09 - 0.10(100 .deg. C). The absorption layers of the Cr-O cermet coatings deposited on glass and silicon substrates were identified as being amorphous by using X-ray diffraction (XRD). Atomic force microscopy (AFM) showed that Cr-O cermet layers were very smooth and that their grain sizes were very small. The result of thermal stability test showed that the Cr-O cermet solar selective coating was stable for use at temperatures of under 400 .deg. C.

  9. Hydraulic shock absorbers

    Thatcher, G.; Davidson, D. F.

    1984-01-01

    A hydraulic shock absorber of the dash pot kind for use with electrically conducting liquid such as sodium, has magnet means for electro magnetically braking a stream of liquid discharged from the cylinder. The shock absorber finds use in a liquid metal cooled nuclear reactor for arresting control rods

  10. Selectively coated high efficiency glazing for solar-thermal flat-plate collectors

    Ehrmann, N.; Reineke-Koch, R.

    2012-01-01

    In order to increase the efficiency of solar-thermal flat-plate collectors at temperatures above 100 °C or with low solar irradiation, we implement a double glazing with a low-emitting (low-e) coating on the inner pane to improve the insulation of the transparent cover. Since commercially available low-e glazing provides only insufficient solar transmittance for the application in thermal flat-plate collectors we are developing a sputter-deposited low e-coating system based on transparent conductive oxides which provides a high solar transmittance of 85% due to additional antireflective coatings and the use of low-iron glass substrates. Durability tests of the developed coating system show that our low e-coating system is well suitable even at high temperatures, humidity and condensation.

  11. BM Solar Cells

    Firdaus, Yuliar

    2018-05-02

    Fullerene‐based materials are widely used as electron acceptors in organic bulk‐heterojunction solar cells; yet, they have rarely been used as the only photoactive component due to their low absorbance and limited charge generation efficiency. However, blending the wide‐bandgap p‐type material copper (I) thiocyanate (CuSCN) with [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC70BM) leads to the formation of a unique mesostructured p‐n like heterointerface between CuSCN and PC70BM and solar cells with a power conversion efficiency (PCE) of up to 5.4%. Here, we examine in detail the reasons for the surprisingly good device performance and elucidate the charge photogeneration and recombination mechanisms in CuSCN‐based devices with PC70BM as the exclusive light‐absorbing material. Our studies clearly demonstrate that a substantial fraction of the photocurrent in the CuSCN‐based devices results from improved dissociation of fullerene excitons and efficient charge transfer at the CuSCN:PC70BM interface combined with reduced geminate and nongeminate charge recombination losses. Our results have implications beyond the fullerene‐based devices studied here, as they demonstrate that careful selection of a mesostructured p‐type transparent semiconductor paves the path to a new type of efficient single photoactive material solar cells.

  12. BM Solar Cells

    Firdaus, Yuliar; Seitkhan, Akmaral; Eisner, Flurin; Sit, Wai-Yu; Kan, Zhipeng; Wehbe, Nimer; Balawi, Ahmed H.; Yengel, Emre; Karuthedath, Safakath; Laquai, Fré dé ric; Anthopoulos, Thomas D.

    2018-01-01

    Fullerene‐based materials are widely used as electron acceptors in organic bulk‐heterojunction solar cells; yet, they have rarely been used as the only photoactive component due to their low absorbance and limited charge generation efficiency. However, blending the wide‐bandgap p‐type material copper (I) thiocyanate (CuSCN) with [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC70BM) leads to the formation of a unique mesostructured p‐n like heterointerface between CuSCN and PC70BM and solar cells with a power conversion efficiency (PCE) of up to 5.4%. Here, we examine in detail the reasons for the surprisingly good device performance and elucidate the charge photogeneration and recombination mechanisms in CuSCN‐based devices with PC70BM as the exclusive light‐absorbing material. Our studies clearly demonstrate that a substantial fraction of the photocurrent in the CuSCN‐based devices results from improved dissociation of fullerene excitons and efficient charge transfer at the CuSCN:PC70BM interface combined with reduced geminate and nongeminate charge recombination losses. Our results have implications beyond the fullerene‐based devices studied here, as they demonstrate that careful selection of a mesostructured p‐type transparent semiconductor paves the path to a new type of efficient single photoactive material solar cells.

  13. Nanostructured refractory thin films for solar applications

    Ollier, E.; Dunoyer, N.; Dellea, O.; Szambolics, H.

    2014-08-01

    Selective solar absorbers are key elements of all solar thermal systems. Solar thermal panels and Concentrated Solar Power (CSP) systems aim respectively at producing heat and electricity. In both cases, a surface receives the solar radiation and is designed to have the highest optical absorption (lowest optical reflectivity) of the solar radiation in the visible wavelength range where the solar intensity is the highest. It also has a low emissivity in the infrared (IR) range in order to avoid radiative thermal losses. Current solutions in the state of the art usually consist in deposited interferential thin films or in cermets [1]. Structured surfaces have been proposed and have been simulated because they are supposed to be more efficient when the solar radiation is not normal to the receiving surface and because they could potentially be fabricated with refractory materials able to sustain high operating temperatures. This work presents a new method to fabricate micro/nanostructured surfaces on molybdenum (refractory metal with a melting temperature of 2623°C). This method now allows obtaining a refractory selective surface with an excellent optical selectivity and a very high absorption in the visible range. This high absorption performance was obtained by achieving a double structuration at micro and nano scales thanks to an innovative process flow.

  14. Optimization of Perfect Absorbers with Multilayer Structures

    Li Voti, Roberto

    2018-02-01

    We study wide-angle and broadband perfect absorbers with compact multilayer structures made of a sequence of ITO and TiN layers deposited onto a silver thick layer. An optimization procedure is introduced for searching the optimal thicknesses of the layers so as to design a perfect broadband absorber from 400 nm to 750 nm, for a wide range of angles of incidence from 0{°} to 50{°}, for both polarizations and with a low emissivity in the mid-infrared. We eventually compare the performances of several optimal structures that can be very promising for solar thermal energy harvesting and collectors.

  15. An algorithm to evaluate solar irradiance and effective dose rates using spectral UV irradiance at four selected wavelengths

    Anav, A.; Rafanelli, C.; Di Menno, I.; Di Menno, M.

    2004-01-01

    The paper shows a semi-analytical method for environmental and dosimetric applications to evaluate, in clear sky conditions, the solar irradiance and the effective dose rates for some action spectra using only four spectral irradiance values at selected wavelengths in the UV-B and UV-A regions (305, 320, 340 and 380 nm). The method, named WL4UV, is based on the reconstruction of an approximated spectral irradiance that can be integrated, to obtain the solar irradiance, or convoluted with an action spectrum to obtain an effective dose rate. The parameters required in the algorithm are deduced from archived solar spectral irradiance data. This database contains measurements carried out by some Brewer spectrophotometers located in various geographical positions, at similar altitudes, with very different environmental characteristics: Rome (Italy), Ny Aalesund (Svalbard Islands (Norway)) and Ushuaia (Tierra del Fuego (Argentina)). To evaluate the precision of the method, a double test was performed with data not used in developing the model. Archived Brewer measurement data, in clear sky conditions, from Rome and from the National Science Foundation UV data set in San Diego (CA, USA) and Ushuaia, where SUV 100 spectro-radiometers operate, were drawn randomly. The comparison of measured and computed irradiance has a relative deviation of about ±2%. The effective dose rates for action spectra of Erythema, DNA and non-Melanoma skin cancer have a relative deviation of less than ∼20% for solar zenith angles <50 deg.. (authors)

  16. Liquid absorber experiments in ZED-2

    McDonnell, F.N.

    1975-07-01

    A set of liquid absorber experiments was performed in ZED-2 to provide data with which to test the adequacy of calculational methods for zone controller and refuelling studies associated with advanced reactor concepts. The absorber consisted of a full length aluminum tube, containing either i)H 2 O, ii)H 2 O + boron (2.5 mg/ml) or iii)H 2 O + boron (8.0 mg/ml). The tube was suspended vertically at interstitial or in-channel locations. A U-tube absorber was also simulated using two absorber tubes with appropriate spacers. Experiments were carried out at two different square lattice pitches, 22.86 and 27.94 cm. Measurements were made of the reactivity effects of the absorbers and, in some cases, of the detailed flux distribution near the perturbation. The results from one calculational method, the source-sink approach, were compared with the data from selected experiments. (author)

  17. Solar Systems

    1979-01-01

    The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

  18. Charge-carrier selective electrodes for organic bulk heterojunction solar cell by contact-printed siloxane oligomers

    Hwang, Hyun-Sik; Khang, Dahl-Young

    2015-01-01

    ‘Smart’ (or selective) electrode for charge carriers, both electrons and holes, in organic bulk-heterojunction (BHJ) solar cells using insertion layers made of hydrophobically-recovered and contact-printed siloxane oligomers between electrodes and active material has been demonstrated. The siloxane oligomer insertion layer has been formed at a given interface simply by conformally-contacting a cured slab of polydimethylsiloxane stamp for less than 100 s. All the devices, either siloxane oligomer printed at one interface only or printed at both interfaces, showed efficiency enhancement when compared to non-printed ones. The possible mechanism that is responsible for the observed efficiency enhancement has been discussed based on the point of optimum symmetry and photocurrent analysis. Besides its simplicity and large-area applicability, the demonstrated contact-printing technique does not involve any vacuum or wet processing steps and thus can be very useful for the roll-based, continuous production scheme for organic BHJ solar cells. - Highlights: • Carrier-selective insertion layer in organic bulk heterojunction solar cells • Simple contact-printing of siloxane oligomers improves cell efficiency. • Printed siloxane layer reduces carrier recombination at electrode surfaces. • Siloxane insertion layer works equally well at both electrode surfaces. • Patterned PDMS stamp shortens the printing time within 100 s

  19. GIS-BASED SOLAR AND WIND TURBINE SITE SELECTION USING MULTI-CRITERIA ANALYSIS: CASE STUDY TEHRAN, IRAN

    M. Sadeghi

    2017-09-01

    Full Text Available Renewable energy has less negative impacts on environment than fossil fuels. Iran has many resources for renewable energy exploitation but because of their high price, it has not been developed. Site selection is an important step for utilizing large investments like solar farms and wind turbines. Multi-criteria evaluation methods are commonly used for site selection. The purpose of this paper is to determine suitable sites for solar farm and wind turbine using GIS and AHP in Tehran, in order to generate a distributed network to increase power network stability. The final land suitability index was grouped in four categories as “most suitable”, “suitable”, “moderate” and “low suitable”. As a result 94.61% (789939.63 km2 is low suitable, 4.47% (37337.17 km2 is moderate, 0.59% (4964.22 km2 is suitable and 0.32% (2680.70 km2 is the most suitable for building wind turbine and for solar farm, 44.07% (8116.88 km2 is low suitable, 12.81% (2359.79 km2 is moderate, 35.10% (6464.29 km2 is suitable and 8.02% (1477.28 km2 is the most suitable.

  20. Gis-Based Solar and Wind Turbine Site Selection Using Multi-Criteria Analysis: Case Study Tehran, Iran

    Sadeghi, M.; Karimi, M.

    2017-09-01

    Renewable energy has less negative impacts on environment than fossil fuels. Iran has many resources for renewable energy exploitation but because of their high price, it has not been developed. Site selection is an important step for utilizing large investments like solar farms and wind turbines. Multi-criteria evaluation methods are commonly used for site selection. The purpose of this paper is to determine suitable sites for solar farm and wind turbine using GIS and AHP in Tehran, in order to generate a distributed network to increase power network stability. The final land suitability index was grouped in four categories as "most suitable", "suitable", "moderate" and "low suitable". As a result 94.61% (789939.63 km2) is low suitable, 4.47% (37337.17 km2) is moderate, 0.59% (4964.22 km2) is suitable and 0.32% (2680.70 km2) is the most suitable for building wind turbine and for solar farm, 44.07% (8116.88 km2) is low suitable, 12.81% (2359.79 km2) is moderate, 35.10% (6464.29 km2) is suitable and 8.02% (1477.28 km2) is the most suitable.

  1. Simple processing of back-contacted silicon heterojunction solar cells using selective-area crystalline growth

    Tomasi, Andrea; Paviet-Salomon, Bertrand; Jeangros, Quentin; Haschke, Jan; Christmann, Gabriel; Barraud, Loris; Descoeudres, Antoine; Seif, Johannes Peter; Nicolay, Sylvain; Despeisse, Matthieu; De Wolf, Stefaan; Ballif, Christophe

    2017-01-01

    For crystalline-silicon solar cells, voltages close to the theoretical limit are nowadays readily achievable when using passivating contacts. Conversely, maximal current generation requires the integration of the electron and hole contacts at the back of the solar cell to liberate its front from any shadowing loss. Recently, the world-record efficiency for crystalline-silicon single-junction solar cells was achieved by merging these two approaches in a single device; however, the complexity of fabricating this class of devices raises concerns about their commercial potential. Here we show a contacting method that substantially simplifies the architecture and fabrication of back-contacted silicon solar cells. We exploit the surface-dependent growth of silicon thin films, deposited by plasma processes, to eliminate the patterning of one of the doped carrier-collecting layers. Then, using only one alignment step for electrode definition, we fabricate a proof-of-concept 9-cm2 tunnel-interdigitated back-contact solar cell with a certified conversion efficiency >22.5%.

  2. Simple processing of back-contacted silicon heterojunction solar cells using selective-area crystalline growth

    Tomasi, Andrea

    2017-04-24

    For crystalline-silicon solar cells, voltages close to the theoretical limit are nowadays readily achievable when using passivating contacts. Conversely, maximal current generation requires the integration of the electron and hole contacts at the back of the solar cell to liberate its front from any shadowing loss. Recently, the world-record efficiency for crystalline-silicon single-junction solar cells was achieved by merging these two approaches in a single device; however, the complexity of fabricating this class of devices raises concerns about their commercial potential. Here we show a contacting method that substantially simplifies the architecture and fabrication of back-contacted silicon solar cells. We exploit the surface-dependent growth of silicon thin films, deposited by plasma processes, to eliminate the patterning of one of the doped carrier-collecting layers. Then, using only one alignment step for electrode definition, we fabricate a proof-of-concept 9-cm2 tunnel-interdigitated back-contact solar cell with a certified conversion efficiency >22.5%.

  3. Application of a temperature selective storage tank solar system. Part 4. Fundamental experiment under a solar simulator; Ondo sentaku chikunetsuso no solar system eno tekiyo. 4. Solar simulator ni yoru kiso jikken

    Kanayama, K; Endo, N; Baba, H; Okamoto, A [Kitami Institute of Technology, Hokkaido (Japan); Kamiya, Y [Kanto Gakuin University, Yokohama (Japan)

    1996-10-27

    The storage tank is classified into a mixed type and stratified type. The stratified type is judged to be more advantageous from a viewpoint of the effective energy utilization. An experiment was made using a solar simulator to put the system, consisting of a vacuum double-glass tube collector and temperature selective storage tank, to practical use. The ejection position of the storage tank at the top is superior to that at the bottom, in the 60{degree}C layer of three layers (60, 40, and 20{degree}C). The ejection position hardly varies with the shape (straight or elbow) of an ejection port. When the temperature stratified layer is formed in two layers (40 {times} 2, 20{degree}C) to three layers (60, 40, and 20{degree}C), heat can be stably stored as the flow rate is higher. The stratified storage tank is inferior to the mixed storage tank in heat collection efficiency, but the specific exergy increases. By increasing the number of heat storage layers, the result of this experiment can also be applied to the linear temperature gradient layer obtained in the practical use. As a result of the above experiment, the basic data for an automated system design during practical application was obtained. 3 refs., 15 figs.

  4. Modeling and characterization of double resonant tunneling diodes for application as energy selective contacts in hot carrier solar cells

    Jehl, Zacharie; Suchet, Daniel; Julian, Anatole; Bernard, Cyril; Miyashita, Naoya; Gibelli, Francois; Okada, Yoshitaka; Guillemolles, Jean-Francois

    2017-02-01

    Double resonant tunneling barriers are considered for an application as energy selective contacts in hot carrier solar cells. Experimental symmetric and asymmetric double resonant tunneling barriers are realized by molecular beam epitaxy and characterized by temperature dependent current-voltage measurements. The negative differential resistance signal is enhanced for asymmetric heterostructures, and remains unchanged between low- and room-temperatures. Within Tsu-Esaki description of the tunnel current, this observation can be explained by the voltage dependence of the tunnel transmission amplitude, which presents a resonance under finite bias for asymmetric structures. This effect is notably discussed with respect to series resistance. Different parameters related to the electronic transmission of the structure and the influence of these parameters on the current voltage characteristic are investigated, bringing insights on critical processes to optimize in double resonant tunneling barriers applied to hot carrier solar cells.

  5. PWR burnable absorber evaluation

    Cacciapouti, R.J.; Weader, R.J.; Malone, J.P.

    1995-01-01

    The purpose of the study was to evaluate the relative neurotic efficiency and fuel cycle cost benefits of PWR burnable absorbers. Establishment of reference low-leakage equilibrium in-core fuel management plans for 12-, 18- and 24-month cycles. Review of the fuel management impact of the integral fuel burnable absorber (IFBA), erbium and gadolinium. Calculation of the U 3 O 8 , UF 6 , SWU, fuel fabrication, and burnable absorber requirements for the defined fuel management plans. Estimation of fuel cycle costs of each fuel management plan at spot market and long-term market fuel prices. Estimation of the comparative savings of the different burnable absorbers in dollar equivalent per kgU of fabricated fuel. (author)

  6. TOMS Absorbing Aerosol Index

    Washington University St Louis — TOMS_AI_G is an aerosol related dataset derived from the Total Ozone Monitoring Satellite (TOMS) Sensor. The TOMS aerosol index arises from absorbing aerosols such...

  7. Fluid selection for a low-temperature solar organic Rankine cycle

    Tchanche, Bertrand Fankam; Papadakis, George; Lambrinos, Gregory; Frangoudakis, Antonios

    2009-01-01

    Theoretical performances as well as thermodynamic and environmental properties of few fluids have been comparatively assessed for use in low-temperature solar organic Rankine cycle systems. Efficiencies, volume flow rate, mass flow rate, pressure ratio, toxicity, flammability, ODP and GWP were used for comparison. Of 20 fluids investigated, R134a appears as the most suitable for small scale solar applications. R152a, R600a, R600 and R290 offer attractive performances but need safety precautions, owing to their flammability.

  8. Electron-selective contacts via ultra-thin organic interface dipoles for silicon organic heterojunction solar cells

    Reichel, Christian; Würfel, Uli; Winkler, Kristina; Schleiermacher, Hans-Frieder; Kohlstädt, Markus; Unmüssig, Moritz; Messmer, Christoph A.; Hermle, Martin; Glunz, Stefan W.

    2018-01-01

    In the last years, novel materials for the formation of electron-selective contacts on n-type crystalline silicon (c-Si) heterojunction solar cells were explored as an interfacial layer between the metal electrode and the c-Si wafer. Besides inorganic materials like transition metal oxides or alkali metal fluorides, also interfacial layers based on organic molecules with a permanent dipole moment are promising candidates to improve the contact properties. Here, the dipole effect plays an essential role in the modification of the interface and effective work function of the contact. The amino acids L-histidine, L-tryptophan, L-phenylalanine, glycine, and sarcosine, the nucleobase adenine, and the heterocycle 4-hydroxypyridine were investigated as dipole materials for an electron-selective contact on the back of p- and n-type c-Si with a metal electrode based on aluminum (Al). Furthermore, the effect of an added fluorosurfactant on the resulting contact properties was examined. The performance of n-type c-Si solar cells with a boron diffusion on the front was significantly increased when L-histidine and/or the fluorosurfactant was applied as a full-area back surface field. This improvement was attributed to the modification of the interface and the effective work function of the contact by the dipole material which was corroborated by numerical device simulations. For these solar cells, conversion efficiencies of 17.5% were obtained with open-circuit voltages (Voc) of 625 mV and fill factors of 76.3%, showing the potential of organic interface dipoles for silicon organic heterojunction solar cells due to their simple formation by solution processing and their low thermal budget requirements.

  9. Energy Absorbing Effectiveness – Different Approaches

    Kotełko Maria

    2018-03-01

    Full Text Available In the paper the study of different crashworthiness indicators used to evaluate energy absorbing effectiveness of thin-walled energy absorbers is presented. Several different indicators are used to assess an effectiveness of two types of absorbing structures, namely thin-walled prismatic column with flaws and thin-walled prismatic frustum (hollow or foam filled in both cases subjected to axial compressive impact load. The indicators are calculated for different materials and different geometrical parameters. The problem of selection of the most appropriate and general indicators is discussed.

  10. Materials science for solar energy conversion systems

    Granqvist, CG

    1991-01-01

    Rapid advances in materials technology are creating many novel forms of coatings for energy efficient applications in solar energy. Insulating heat mirrors, selective absorbers, transparent insulation and fluorescent concentrators are already available commercially. Radiative cooling, electrochromic windows and polymeric light pipes hold promise for future development, while chemical and photochemical processes are being considered for energy storage. This book investigates new material advances as well as applications, costs, reliability and industrial production of existing materials. Each c

  11. Developing Efficient Charge-Selective Interfacial Materials for Polymer and Perovskite Solar Cells

    2016-01-25

    planar heterojunction perovskite solar cells Among the developed inorganic p-type HTL for PVSCs, nickel oxide (NiOx) has attracted the most...solution processable, doped transition metal oxide -based hole-transporting interlayer (HTL) to significantly improve the photovoltaic performance and...public release: distribution unlimited. PVSC device architectures developed so far, the planar heterojunction configuration attracts particular

  12. Industrially feasible, dopant-free, carrier-selective contacts for high-efficiency silicon solar cells

    Yang, Xinbo; Weber, Klaus; Hameiri, Ziv; De Wolf, Stefaan

    2017-01-01

    quality and cell processing, a remarkable efficiency of 22.1% has been achieved using an n-type silicon solar cell featuring a full-area TiO contact. Next, we demonstrate the compatibility of TiO contacts with an industrial contact-firing process, its low

  13. Debundling and Selective Enrichment of SWNTs for Applications in Dye-Sensitized Solar Cells

    F. Bonaccorso

    2010-01-01

    Full Text Available We present an overview of the recent developments in de-bundling and sorting of Single-Wall Carbon Nanotubes (SWNTs, which are useful for hi-tech applications in dye sensitized solar cells (DSSCs. Applications of SWNTs as transparent and conductive films, catalyst, and scaffold in DSSCs are also reviewed.

  14. Study of the Mg incorporation in CdTe for developing wide band gap Cd1−xMgxTe thin films for possible use as top-cell absorber in a tandem solar cell

    Martínez, Omar S.; Millán, Aduljay Remolina; Huerta, L.; Santana, G.; Mathews, N.R.; Ramon-Garcia, M.L.; Morales, Erik R.; Mathew, X.

    2012-01-01

    Highlights: ► Thin films of Cd 1−x Mg x Te with high spatial uniformity and band gap in the range of 1.6–1.96 eV were deposited by vacuum co-evaporation of CdTe and Mg. ► Obtained Cd 1−x Mg x Te films have the structural characteristics of the CdTe, evidence of the change in atomic scattering due to incorporation of Mg was observed. ► XRD and XPS data confirmed the incorporation of Mg in the lattice of CdTe. ► SEM images revealed the impact of Mg incorporation on the morphology of the films, the changes in grain size and grain morphology are noticeable. - Abstract: Thin films of Cd 1−x Mg x Te with band gap in the range of 1.6–1.96 eV were deposited by vacuum co-evaporation of CdTe and Mg on glass substrates heated at 300 °C. Different experimental techniques such as XRD, UV–vis spectroscopy, SEM, and XPS were used to study the effect of Mg incorporation into the lattice of CdTe. The band gap of the films showed a clear tendency to increase as the Mg content in the film is increased. The Cd 1−x Mg x Te films maintain all the structural characteristics of the CdTe, however, diminishing of intensity for the XRD patterns is observed due to both change in preferential orientation and change in atomic scattering due to the incorporation of Mg. SEM images showed significant evidences of morphological changes due to the presence of Mg. XRD, UV–vis spectroscopy, and XPS data confirmed the incorporation of Mg in the lattice of CdTe. The significant increase in band gap of CdTe due to incorporation of Mg suggests that the Cd 1−x Mg x Te thin film is a candidate material to use as absorber layer in the top-cell of a tandem solar cell.

  15. Study of the Mg incorporation in CdTe for developing wide band gap Cd{sub 1-x}Mg{sub x}Te thin films for possible use as top-cell absorber in a tandem solar cell

    Martinez, Omar S. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico); Universidad Politecnica del Estado de Guerrero, Comunidad de Puente Campuzano, C.P. 40325 Taxco de Alarcon, Guerrero (Mexico); Millan, Aduljay Remolina [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico); Huerta, L.; Santana, G. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico. C.P 04510 Mexico D.F. (Mexico); Mathews, N.R.; Ramon-Garcia, M.L.; Morales, Erik R. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico); Mathew, X., E-mail: xm@cie.unam.mx [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, 62580 Temixco, Morelos (Mexico)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Thin films of Cd{sub 1-x}Mg{sub x}Te with high spatial uniformity and band gap in the range of 1.6-1.96 eV were deposited by vacuum co-evaporation of CdTe and Mg. Black-Right-Pointing-Pointer Obtained Cd{sub 1-x}Mg{sub x}Te films have the structural characteristics of the CdTe, evidence of the change in atomic scattering due to incorporation of Mg was observed. Black-Right-Pointing-Pointer XRD and XPS data confirmed the incorporation of Mg in the lattice of CdTe. Black-Right-Pointing-Pointer SEM images revealed the impact of Mg incorporation on the morphology of the films, the changes in grain size and grain morphology are noticeable. - Abstract: Thin films of Cd{sub 1-x}Mg{sub x}Te with band gap in the range of 1.6-1.96 eV were deposited by vacuum co-evaporation of CdTe and Mg on glass substrates heated at 300 Degree-Sign C. Different experimental techniques such as XRD, UV-vis spectroscopy, SEM, and XPS were used to study the effect of Mg incorporation into the lattice of CdTe. The band gap of the films showed a clear tendency to increase as the Mg content in the film is increased. The Cd{sub 1-x}Mg{sub x}Te films maintain all the structural characteristics of the CdTe, however, diminishing of intensity for the XRD patterns is observed due to both change in preferential orientation and change in atomic scattering due to the incorporation of Mg. SEM images showed significant evidences of morphological changes due to the presence of Mg. XRD, UV-vis spectroscopy, and XPS data confirmed the incorporation of Mg in the lattice of CdTe. The significant increase in band gap of CdTe due to incorporation of Mg suggests that the Cd{sub 1-x}Mg{sub x}Te thin film is a candidate material to use as absorber layer in the top-cell of a tandem solar cell.

  16. Tunnel oxide passivated rear contact for large area n-type front junction silicon solar cells providing excellent carrier selectivity

    Yuguo Tao

    2016-01-01

    Full Text Available Carrier-selective contact with low minority carrier recombination and efficient majority carrier transport is mandatory to eliminate metal-induced recombination for higher energy conversion efficiency for silicon (Si solar cells. In the present study, the carrier-selective contact consists of an ultra-thin tunnel oxide and a phosphorus-doped polycrystalline Si (poly-Si thin film formed by plasma enhanced chemical vapor deposition (PECVD and subsequent thermal crystallization. It is shown that the poly-Si film properties (doping level, crystallization and dopant activation anneal temperature are crucial for achieving excellent contact passivation quality. It is also demonstrated quantitatively that the tunnel oxide plays a critical role in this tunnel oxide passivated contact (TOPCON scheme to realize desired carrier selectivity. Presence of tunnel oxide increases the implied Voc (iVoc by ~ 125 mV. The iVoc value as high as 728 mV is achieved on symmetric structure with TOPCON on both sides. Large area (239 cm2 n-type Czochralski (Cz Si solar cells are fabricated with homogeneous implanted boron emitter and screen-printed contact on the front and TOPCON on the back, achieving 21.2% cell efficiency. Detailed analysis shows that the performance of these cells is mainly limited by boron emitter recombination on the front side.

  17. Solar receiver with integrated optics

    Jiang, Lun; Winston, Roland

    2012-10-01

    The current challenge for PV/Thermal (PV/T) systems is the reduction of radiation heat loss. Compared to solar thermal selective coating, the solar cells cannot be used as an efficient thermal absorber due to their large emissivity of the encapsulation material. Many commercial PV/T products therefore require a high concentration (more than 10x) to reach an acceptable thermal efficiency for their receivers. Such a concentration system inevitably has to track or semi-track, which induces additional cost and collects only the direct radiation from the sun. We propose a new PV/T design using a vacuum encapsulated thin film cell to solve this problem. The proposed design also collects the diffuse sun light efficiently by using an external compound parabolic concentrator (XCPC). Since the transparent electrode (TCO) of thin film cell is inherently transparent in visible light and reflective beyond infrared, this design uses this layer instead of the conventional solar cell encapsulation as the outmost heat loss surface. By integrating such a vacuum design with a tube shaped absorber, we reduce the complexity of conducting the heat energy and electricity out of the device. A low concentration standalone non-tracking solar collector is proposed in this paper. We also analyzed the thermosyphon system configuration using heat transfer and ray tracing models. The economics of such a receiver are presented.

  18. Daylight and solar control in buildings. General evaluation and optimization of a new angle selective glazing facade

    Frontini, Francesco

    2011-07-01

    Buildings account for almost 40% of the overall energy consumption in Europe. For the future energy scenarios, the building envelope, especially the facades, becomes really important as it provides the necessary area for the installation of PV modules or solar collectors to produce energy, using renewable energy sources. A new multifunctional building integrated photovoltaic (BIPV) glazed facade for this application is presented here. The new angle-selective see through facade combines four important tasks in one element: solar control, glare protection, visual contact and electricity generation. Mathematical analysis and complex simulations with the software Radiance are performed to optimize the geometry and to assess the visual impact and optical properties of the new window. In order to evaluate the impact of the new facade in building spaces a new method for modelling the total solar energy transmittance, in building energy simulations software, for complex glazing facades is presented. The new black-box-model (BBM) is implemented into ESP-r software and is validated. The BBM is used to assess the impact of modelling accurately the g-value of complex facade within building simulation. It is shown that the new method can significantly increase the accuracy of heating/cooling loads and room temperatures. (orig.)

  19. Experimental Study on Fabrication of AZO Transparent Electrode for Organic Solar Cell Using Selective Low-Temperature Atomic Layer Deposition

    Kim, Kicheol; Song, Gensoo; Kim, Hyungtae; Yoo, Kyunghoon; Kang, Jeongjin; Hwang, Junyoung; Lee, Sangho; Kang, Kyungtae; Kang, Heuiseok; Cho, Youngjune

    2013-01-01

    AZO (aluminum-doped zinc oxide) is one of the best candidate materials to replace Into (indium tin oxide) for TKOs (transparent conductive oxides) used in flat panel displays, organic light-emitting diodes (OLDS), and organic solar cells (OCSS). In the present study, to apply an AZO thin film to the transparent electrode of an organic solar cell, a low temperature selective atomic layer deposition (ALD) process was adopted to deposit an AZO thin film on a flexible polyethylene-naphthanate (Pen) substrate. The reactive gases for the ALD process were di-ethyl-zinc (De) and tri-methylaluminum (Tma) as precursors and H 2 O as an oxidant. The structural, electrical, and optical characteristics of the AZO thin film were evaluated. From the measured results of the electrical and optical characteristics of the AZO thin films deposited on the Pen substrates by Ald, it was shown that the Azo thin film appeared to be comparable to a commercially used Into thin film, which confirmed the feasibility of AZO as a TCO for flexible organic solar cells in the near future

  20. Selective removal of CuIn1−xGaxSe2 absorber layer with no edge melting using a nanosecond Nd : YAG laser

    Lee, S H; Kim, C K; In, J H; Jeong, S H; Shim, H S

    2013-01-01

    This paper reports that selective removal of a CuIn 1−x Ga x Se 2 (CIGS) thin film on a Mo-coated glass substrate can be achieved with no edge melting or damage of the Mo layer using a nanosecond Nd : YAG laser with a wavelength of 1064 nm. It is shown that the two crucial parameters that determine the possibility of clean removal of only the CIGS layer are Ga concentration of the CIGS film and laser fluence. For CIGS films with Ga/(Ga+In) ratio greater than about 0.2 for which the band gap energy is close to or over the photon energy (1.17 eV), laser-induced thermal expansion proved to be the mechanism of film removal that drives an initial bulging of the film and then fracture into tens of micrometre sized fragments as observed in in situ shadowgraph images. The fracture-type removal of CIGS films was further verified by scanning electron micrographs of the craters showing that the original shapes of the CIGS polycrystals remain intact along the crater rim. A numerical simulation of film temperature under the irradiation conditions of selective removal was carried out to show that the magnitude of induced thermal stress within the film closely agreed to the yield strength of the CIGS thin film. The results confirmed that a nanosecond laser could be a better choice for P2 and P3 scribing of CIGS thin films if process conditions are properly determined. (paper)

  1. Ti O{sub 2}-Based Solar Photocatalytic Degradation of Selected pesticides in aqueous solutions

    Bernecker, A.; Baune, M.; Malato, S.; Thiemann, W.

    1999-07-01

    The photocatalytic oxidation of the pesticides pirimicarb and imidacloprid, using Ti O{sub 2} suspensions under solar radiation, has been studied at pilot-plant scale at the Plataforma Solar de Almeria. The effect of the added Ti O{sub 2}-concentration (ranging from 0 to 1000 mg.dm''-3) and the pH value of the solution (pH values 3, 7 and 10) on the decomposition rates of pirimicarb and imidacloprid oxidation was examined. Addition of Ti O{sub 2} leads to an increase in the reaction rates of both investigated pollutants. A pH dependence is also obvious, but not similar for both pesticides. (Author) 10 refs.

  2. Towards hybrid heterojunction silicon solar cells with organic charge carrier selective contacts

    Jäckle, Sara Lisa

    2017-01-01

    Photovoltaic is an essential part of the needed global transition towards renewable energies. Even though many materials have good absorption and energy conversion properties, the market is dominated by technologies based on crystalline silicon. Silicon has the advantage of being neither toxic nor rare on earth and it is very well investigated due to its extensive use in microelectronics. The best power conversion efficiencies of silicon solar cells and modules are achieved by sophisticated d...

  3. Neutron absorbing article

    Naum, R.G.; Owens, D.P.; Dooher, G.I.

    1979-01-01

    A neutron absorbing article, in flat plate form and suitable for use in a storage rack for spent fuel, includes boron carbide particles, diluent particles and a solid, irreversibly cured phenolic polymer cured to a continuous matrix binding the boron carbide and diluent particles. The total conent of boron carbide and diluent particles is a major proportion of the article and the content of cured phenolic polymer present is a minor proportion. By regulation of the ratio of boron carbide particles to diluent particles, normally within the range of 1:9 and 9:1 and preferably within the range of 1:5 to 5:1, the neutron absorbing activity of the product may be controlled, which facilitates the manufacture of articles of particular absorbing activities best suitable for specific applications

  4. Burnable neutron absorbers

    Radford, K.C.; Carlson, W.G.

    1983-01-01

    A neutron-absorber body for use in burnable poison rods in a nuclear reactor. The body is composed of a matrix of Al 2 O 3 containing B 4 C, the neutron absorber. Areas of high density polycrystalline Al 2 O 3 particles are predominantly encircled by pores in some of which there are B 4 C particles. This body is produced by initially spray drying a slurry of A1 2 O 3 powder to which a binder has been added. The powder of agglomerated spheres of the A1 2 O 3 with the binder are dry mixed with B 4 C powder. The mixed powder is formed into a green body by isostatic pressure and the green body is sintered. The sintered body is processed to form the neutron-absorber body. In this case the B 4 C particles are separate from the spheres resulting from the spray drying instead of being embedded in the sphere

  5. Optimization, selection and feasibility study of solar parabolic trough power plants for Algerian conditions

    Boukelia, T.E.; Mecibah, M.S.; Kumar, B.N.; Reddy, K.S.

    2015-01-01

    Highlights: • Evaluation of solar resources in the absence of measured data. • Optimization of 2 PTSTPPs integrated with TES and FBS and using oil and salt as HTFs. • 4E comparative study of the two optimized plants alongside the Andasol 1 plant. • The salt plant resulting as the best one and has been chosen for the viability study. • Tamanrasset is the best location for construction of PTSTPPs. - Abstract: In the present study, optimization of two parabolic trough solar thermal power plants integrated with thermal energy storage (TES), and fuel backup system (FBS) has been performed. The first plant uses Therminol VP-1 as heat transfer fluid in the solar field and the second plant uses molten salt. The optimization is carried out with solar multiple (SM) and full load hours of TES as the parameters, with an objective of minimizing the levelized cost of electricity (LCOE) and maximizing the annual energy yield. A 4E (energy–exergy–environment–economic) comparison of the optimized plants alongside the Andasol 1 as reference plant is studied. The molten salt plant resulting as the best technology, from the optimization and 4E comparative study has been chosen for the viability analysis of ten locations in Algeria with semi-arid and arid climatic conditions. The results indicate that Andasol 1 reference plant has the highest mean annual energy efficiency (17.25%) and exergy efficiency (23.30%). Whereas, the highest capacity factor (54.60%) and power generation (236.90 GW h) are exhibited by the molten salt plant. The molten salt plant has least annual water usage of about 800,482 m 3 , but demands more land for the operation. Nevertheless the oil plant emits the lowest amount of CO 2 gas (less than 40.3 kilo tonnes). From the economic viewpoint, molten salt seems to be the best technology compared to other plants due to its lowest investment cost (less than 360 million dollars) and lower levelized cost of electricity (LCOE) (8.48 ¢/kW h). The

  6. Neutron absorbing article

    Naum, R.G.; Owens, D.P.; Dooker, G.I.

    1981-01-01

    A neutron-absorbing article suitable for use in spent fuel racks is described. It comprises boron carbide particles, diluent particles, and a phenolic polymer cured to a continuous matrix. The diluent may be silicon carbide, graphite, amorphous carbon, alumina, or silica. The combined boron carbide-diluent phase contains no more than 2 percent B 2 O 3 , and the neutron-absorbing article contains from 20 to 40 percent phenol resin. The ratio of boron carbide to diluent particles is in the range 1:9 to 9:1

  7. 19.2% Efficient InP Heterojunction Solar Cell with Electron-Selective TiO2 Contact.

    Yin, Xingtian; Battaglia, Corsin; Lin, Yongjing; Chen, Kevin; Hettick, Mark; Zheng, Maxwell; Chen, Cheng-Ying; Kiriya, Daisuke; Javey, Ali

    2014-12-17

    We demonstrate an InP heterojunction solar cell employing an ultrathin layer (∼10 nm) of amorphous TiO 2 deposited at 120 °C by atomic layer deposition as the transparent electron-selective contact. The TiO 2 film selectively extracts minority electrons from the conduction band of p-type InP while blocking the majority holes due to the large valence band offset, enabling a high maximum open-circuit voltage of 785 mV. A hydrogen plasma treatment of the InP surface drastically improves the long-wavelength response of the device, resulting in a high short-circuit current density of 30.5 mA/cm 2 and a high power conversion efficiency of 19.2%.

  8. Solar heating pipe

    Hinson-Rider, G.

    1977-10-04

    A fluid carrying pipe is described having an integral transparent portion formed into a longitudinally extending cylindrical lens that focuses solar heat rays to a focal axis within the volume of the pipe. The pipe on the side opposite the lens has a heat ray absorbent coating for absorbing heat from light rays that pass through the focal axis.

  9. Analysis of the thermal performance of a solar heating system using a collector with absorbing surface in plates coated with PVC; Analise do desempenho termico de um sistema de aquecimento solar utilizando coletor com superficie absorvedora em chapas de forro de PVC

    Reis, Edmilson Pedreira dos

    2009-08-15

    It is presented a solar collector to be used in a system for heating bath water, whose main characteristic is its low cost. The collector consists of five plates of PVC with 10 mm thick, 200 mm wide and 1400 mm length, with ao area equal to 1,4 square meters. The plates were connected in parallel to the ends of PVC tubes of 40 mm diameter and 32 mm diameter. The plates were coated on one side with aluminum sheets of soft drinks and beers cans open. The system worked on a thermosyphon and was tested in two configurations: the plates uncoated and coated with aluminum material, to determine the influence of material on the efficiency of the collector. For both configurations was used EPS plates below the surface to minimize heat losses from the bottom. The thermal reservoir of the heating system is, also, alternative and of low cost, since it was constructed from a polyethylene tank for storing water, with volume of 150 end 200 liters. It will be presented the thermal efficiency, heat loss, water temperature of the thermal reservoir at the end of the process and simulation of baths for a house with four residents. It will be demonstrated the thermal, economic and material viability of the proposed collector, whose main innovation is the use of recyclable materials, cans of beer and soft drinks, to increase the temperature of the absorber plate. (author)

  10. Solar India - 82: national solar energy convention

    1982-01-01

    This document is the proceedings of the Solar India - 82 conference, which was held 17-19 December 1982. The papers are organized into functional groupings which include: (1) solar radiation, (2) flat plate solar collectors and solar water heaters, (3) solar concentrators, (4) solar air heaters and dryers, (5) solar ponds and energy storage, (6) solar cookers, (7) solar stills, (8) selective coatings, (9) photovoltaics, (10) space heating and cooling, (11) bio-energy, and (12) miscellaneous papers. The vast majority of the papers describe work carried out in India, the vast majority of the papers also contain relatively readable abstracts.

  11. Low Absorbance Measurements

    Harris, T. D.; Williams, A. M.

    1983-10-01

    The application of low absorption measurements to dilute solute determination requires specific instrumental characteristics. The use of laser intracavity absorption and thermal lens calorimetry to measure concentration is shown. The specific operating parameters that determine sensitivity are delineated along with the limits different measurement strategies impose. Finally areas of improvement in components that would result in improve sensitivity, accuracy, and reliability are discussed. During the past decade, a large number of methods have been developed for measuring the light absorbed by transparent materials. These include measurements on gases, liquids, and solids. The activity has been prompted by a variety of applications and a similar variety of disciplines. In Table 1 some representative examples of these methods is shown along with their published detection limits.1 It is clear that extraordinarily small absorbances can be measured. Most of the methods can be conveniently divided into two groups. These groups are those that measure the transmission of the sample and those that measure the light absorbed by the sample. The light absorbed methods are calorimetric in character. The advantages and disadvantages of each method varies depending on the principal application for which they were developed. The most prevalent motivation has been to characterize the bulk optical properties of transparent materials. Two examples are the development of extremely transparent glasses for use as fiber optic materials and the development of substrates for high power laser operation.

  12. ANALYSIS OF THE POSSIBILITY OF USING SOLAR ENERGY TO POWER SELECTED MEASURING DRIVES IN AGRICULTURE

    Jan Marian Kolano

    2017-01-01

    Full Text Available Mankind’s misgivings caused by the depletion of fossil fuels have accelerated research on obtaining energy from unconventional sources. One such source is the Sun. The present article reviews the possibility of using solar energy, converted in batteries of photovoltaic cells into electricity, in agriculture and farming. It should also be emphasized that it is energy friendly to the environment, whose acquisition on agricultural land, which often lacks access to the power grid, is now legitimate and profitable. This study presents the results of computer simulations in tabular and graphical form, using the PVSYST program, for a pasture water pumping system for watering grazing cattle.

  13. Strategies for increasing the efficiency of heterojunction organic solar cells: material selection and device architecture.

    Heremans, Paul; Cheyns, David; Rand, Barry P

    2009-11-17

    Thin-film blends or bilayers of donor- and acceptor-type organic semiconductors form the core of heterojunction organic photovoltaic cells. Researchers measure the quality of photovoltaic cells based on their power conversion efficiency, the ratio of the electrical power that can be generated versus the power of incident solar radiation. The efficiency of organic solar cells has increased steadily in the last decade, currently reaching up to 6%. Understanding and combating the various loss mechanisms that occur in processes from optical excitation to charge collection should lead to efficiencies on the order of 10% in the near future. In organic heterojunction solar cells, the generation of photocurrent is a cascade of four steps: generation of excitons (electrically neutral bound electron-hole pairs) by photon absorption, diffusion of excitons to the heterojunction, dissociation of the excitons into free charge carriers, and transport of these carriers to the contacts. In this Account, we review our recent contributions to the understanding of the mechanisms that govern these steps. Starting from archetype donor-acceptor systems of planar small-molecule heterojunctions and solution-processed bulk heterojunctions, we outline our search for alternative materials and device architectures. We show that non-planar phthalocynanines have appealing absorption characteristics but also have reduced charge carrier transport. As a result, the donor layer needs to be ultrathin, and all layers of the device have to be tuned to account for optical interference effects. Using these optimization techniques, we illustrate cells with 3.1% efficiency for the non-planar chloroboron subphthalocyanine donor. Molecules offering a better compromise between absorption and carrier mobility should allow for further improvements. We also propose a method for increasing the exciton diffusion length by converting singlet excitons into long-lived triplets. By doping a polymer with a

  14. Infiltration and Selective Interactions at the Interface in Polymer-Oxide Hybrid Solar Cells

    Ferragut, R.; Aghion, S.; Moia, F.; Binda, M.; Canesi, E. V.; Lanzani, G.; Petrozza, A.

    2013-06-01

    Positron annihilation spectroscopy was used to characterize polymer-based hybrid solar cells formed by poly(3-hexylthiophene) (P3HT) finely infiltrated in a porous TiO2 skeleton. A step-change improvement in the device performance is enabled by engineering the hybrid interface by the insertion of a proper molecular interlayer namely 4-mercaptopyridine (4-MP). In order to obtain depth-resolved data, positrons were implanted in the sample using a variable-energy positron beam. The characteristics of the partially filled nanoporous structures were evaluated in terms of the depth profile of the positronium yield and the S-parameter. A quantitative evaluation of the pore filling in the deep region is given from the analysis of Coincidence Doppler Broadening taken at fixed implantation energy. We note a remarkable difference in terms of the positronium yield when the 4-MP interlayer is introduced, which means a better covering of P3HT on the porous surface.

  15. Solar electricity and solar fuels

    Spiers, David J.

    1989-04-01

    The nature of solar radiation and its variation with location is described. The distribution of energy in the solar spectrum places immediate limits on the theoretical efficiency of conversion processes, since practical absorbers cannot convert all wavelengths received to useful energy. The principles of solar energy conversion methods are described. Absorption of solar energy can give rise to direct electrical generation, heating, or chemical change. Electrical generation from sunlight can be achieved by photovoltaic systems directly or by thermal systems which use solar heat to drive a heat engine and generator. The technology used and under research for promising ways of producing electricity or fuel from solar energy is described. Photovoltaic technology is established today for remote area, small power applications, and photovoltaic module sales alone are over 100 million dollars per year at present. The photovoltaic market has grown steadily since the mid-1970's, as prices have fallen continuously. Future energy options are briefly described. The merits of a sustainable energy economy, based on renewable energy resources, including solar energy, are emphasized, as this seems to provide the only hope of eliminating the problems caused by the build-up of atmospheric carbon dioxide, acid rain pollution and nuclear waste disposal. There is no doubt that clean fuels which were derived from solar energy and either did not involve carbon dioxide and used atmospheric carbon dioxide as the source dioxide as the source of carbon would be a worthy ideal. Methods described could one day achieve this.

  16. Performance Comparisons and Down Selection of Small Motors for Two-Blade Heliogyro Solar Sail 6U CubeSat

    Wiwattananon, Peerawan; Bryant, Robert G.

    2015-01-01

    This report compiles a review of 130 commercial small scale motors (piezoelectric and electric motors) and almost 20 researched-type small scale piezoelectricmotors for potential use in a 2 blades Heliogyro Solar Sail 6U CubeSat. In this application, a motor and gearhead (drive system) will deploy a roll of solar sailthin film (2 um thick)accommodated in a 2U CubeSat (100 x 200 x 100 mm) housing. The application requirements are: space rated, output torque at fulldeployment of 0.8 Nm, reel speed of 3 rpm, drive system weight limited to 150 grams, diameter limited to 50 mm, and the length not to exceed 40 mm. The 50mm diameter limit was imposed as motors with larger diameters would likely weigh too much and use more space on the satellite wall. This would limit theamount of the payload. The motors performance are compared between small scale, volume within 3x102 cm3 (3x105 mm3), commercial electric DC motors,commercial piezoelectric motors, and researched-type (non-commercial) piezoelectric motors extracted from scientific and product literature. The comparisonssuggest that piezoelectric motors without a gearhead exhibit larger output torque with respect to their volume and weight and require less input power toproduce high torque. A commercially available electric motor plus a gearhead was chosen through a proposed selection process to meet the applications designrequirements.

  17. Adjustable Shock Absorbers

    Adamiec, Radek

    2012-01-01

    Bakalářská práce obsahuje přehled používaných tlumičů osobních automobilů, závodních automobilů a motocyklů. Jsou zde popsány systémy t lumením, konstrukce tlumičů a vidlic používaných u motocyklů. Dále je zde přehled prvků používaných u podvozků automobilů. This bachelor´s thesis contains the survey of the shock absorbers of passenger cars, racing cars and motorcycles. Are described damping systems, the design used shock absorbers and forks for motorcycles. Then there is the list of the e...

  18. Kinetic energy absorbing pad

    Bricmont, R.J.; Hamilton, P.A.; Ming Long Ting, R.

    1981-01-01

    Reactors, fuel processing plants etc incorporate pipes and conduits for fluids under high pressure. Fractures, particularly adjacent to conduit elbows, produce a jet of liquid which whips the broken conduit at an extremely high velocity. An enormous impact load would be applied to any stationary object in the conduit's path. The design of cellular, corrugated metal impact pads to absorb the kinetic energy of the high velocity conduits is given. (U.K.)

  19. Absorbable and biodegradable polymers

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  20. A novel design for a cheap high temperature solar collector: The rotating solar boiler

    Luijtelaer, van J.P.H.; Kroon, M.C.

    2009-01-01

    In this work a novel type of high temperature solar collector is designed: the rotating solar boiler. This rotating solar boiler consists of two concentric tubes. The inner tube, called absorber, absorbs sunlight and boils water. The outer transparent tube, called cover, is filled with air. The

  1. Burnable neutron absorbers

    Radford, K.C.; Carlson, W.G.

    1985-01-01

    This patent deals with the fabrication of pellets for neutron absorber rods. Such a pellet includes a matrix of a refractory material which may be aluminum or zirconium oxide, and a burnable poison distributed throughout the matrix. The neutron absorber material may consist of one or more elements or compounds of the metals boron, gadolinium, samarium, cadmium, europium, hafnium, dysprosium and indium. The method of fabricating pellets of these materials outlined in this patent is designed to produce pores or voids in the pellets that can be used to take up the expansion of the burnable poison and to absorb the helium gas generated. In the practice of this invention a slurry of Al 2 O 3 is produced. A hard binder is added and the slurry and binder are spray dried. This powder is mixed with dry B 4 C powder, forming a homogeneous mixture. This mixture is pressed into green tubes which are then sintered. During sintering the binder volatilizes leaving a ceramic with nearly spherical high-density regions of

  2. Application of a temperature selective heat storage tank to a solar system. Part 3. Solar heat collecting system; Ondo sentaku chikunetsuso no solar system eno tekiyo. 3. Shunetsu hoshiki ni tsuite

    Kamiya, Y [Kanto Gakuin University, Yokohama (Japan); Kanayama, K [Kitami Institute of Technology, Hokkaido (Japan)

    1996-10-27

    The tank system and tank-less system when the temperature selective heat storage tank is applied to a solar system were considered. In the tank system, the simulation shows that the annual supplementary heat consumption is reduced as the tank capacity becomes lower. The most suitable operating time set for determining the reference time is about five hours in winter and about nine hours in summer. The annual operating time is about 6.5 hours. In the tank-less system, the most suitable minimum flow rate per solar collector area of a heating medium in Tokyo and its districts is 10 L/hm{sup 2} for both three-step flow control and constant flow control. The tank-less system is slightly lower in annual supplementary heat consumption than the tank system. For the three-step flow control, a change in the annual supplementary heat consumption is lower than that in the minimum flow rate. For the constant flow control, however, the annual supplementary heat consumption rapidly increases when the flow rate more decreases than the optimum value. The number of pump start/stop counts for the three-step flow control is less than two times as high as for the constant flow control. 4 refs., 6 figs., 1 tab.

  3. Selective observation of photo-induced electric fields inside different material components in bulk-heterojunction organic solar cell

    Chen, Xiangyu; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1, S3-33 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-01-06

    By using electric-field-induced optical second-harmonic generation (EFISHG) measurement at two laser wavelengths of 1000 nm and 860 nm, we investigated carrier behavior inside the pentacene and C{sub 60} component of co-deposited pentacene:C{sub 60} bulk-heterojunctions (BHJs) organic solar cells (OSCs). The EFISHG experiments verified the presence of two carrier paths for electrons and holes in BHJs OSCs. That is, two kinds of electric fields pointing in opposite directions are identified as a result of the selectively probing of SHG activation from C{sub 60} and pentacene. Also, under open-circuit conditions, the transient process of the establishment of open-circuit voltage inside the co-deposited layer has been directly probed, in terms of photovoltaic effect. The EFISHG provides an additional promising method to study carrier path of electrons and holes as well as dissociation of excitons in BHJ OSCs.

  4. Numerical analysis of radiation propagation in innovative volumetric receivers based on selective laser melting techniques

    Alberti, Fabrizio; Santiago, Sergio; Roccabruna, Mattia; Luque, Salvador; Gonzalez-Aguilar, Jose; Crema, Luigi; Romero, Manuel

    2016-05-01

    Volumetric absorbers constitute one of the key elements in order to achieve high thermal conversion efficiencies in concentrating solar power plants. Regardless of the working fluid or thermodynamic cycle employed, design trends towards higher absorber output temperatures are widespread, which lead to the general need of components of high solar absorptance, high conduction within the receiver material, high internal convection, low radiative and convective heat losses and high mechanical durability. In this context, the use of advanced manufacturing techniques, such as selective laser melting, has allowed for the fabrication of intricate geometries that are capable of fulfilling the previous requirements. This paper presents a parametric design and analysis of the optical performance of volumetric absorbers of variable porosity conducted by means of detailed numerical ray tracing simulations. Sections of variable macroscopic porosity along the absorber depth were constructed by the fractal growth of single-cell structures. Measures of performance analyzed include optical reflection losses from the absorber front and rear faces, penetration of radiation inside the absorber volume, and radiation absorption as a function of absorber depth. The effects of engineering design parameters such as absorber length and wall thickness, material reflectance and porosity distribution on the optical performance of absorbers are discussed, and general design guidelines are given.

  5. High-temperature thermal storage systems for advanced solar receivers materials selections

    Wilson, D. F.; Devan, J. H.; Howell, M.

    1990-01-01

    Advanced space power systems that use solar energy and Brayton or Stirling heat engines require thermal energy storage (TES) systems to operate continuously through periods of shade. The receiver storage units, key elements in both Brayton and Stirling systems, are designed to use the latent heat of fusion of phase-change materials (PCMs). The power systems under current consideration for near-future National Aeronautics and Space Administration space missions require working fluid temperatures in the 1100 to 1400 K range. The PCMs under current investigation that gave liquid temperatures within this range are the fluoride family of salts. However, these salts have low thermal conductivity, which causes large temperature gradients in the storage systems. Improvements can be obtained, however, with the use of thermal conductivity enhancements or metallic PCMs. In fact, if suitable containment materials can be found, the use of metallic PCMs would virtually eliminate the orbit associated temperature variations in TES systems. The high thermal conductivity and generally low volume change on melting of germanium and alloys based on silicon make them attractive for storage of thermal energy in space power systems. An approach to solving the containment problem, involving both chemical and physical compatibility, preparation of NiSi/NiSi2, and initial results for containment of germanium and NiSi/NiSi2, are presented.

  6. Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

    Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

    1987-01-01

    Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

  7. Shock absorber in Ignalina NPP

    Bulavas, A.; Muralis, J.

    1996-09-01

    Theoretical calculation and experimental analysis of models of shock absorber in Ignalina NPP is presented. The results obtained from the investigation with model of shock absorber coincide with the theoretical calculation. (author). 2 figs., 3 refs

  8. Absorber for terahertz radiation management

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  9. Corrosion resistant neutron absorbing coatings

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  10. Feynman Integrals with Absorbing Boundaries

    Marchewka, A.; Schuss, Z.

    1997-01-01

    We propose a formulation of an absorbing boundary for a quantum particle. The formulation is based on a Feynman-type integral over trajectories that are confined to the non-absorbing region. Trajectories that reach the absorbing wall are discounted from the population of the surviving trajectories with a certain weighting factor. Under the assumption that absorbed trajectories do not interfere with the surviving trajectories, we obtain a time dependent absorption law. Two examples are worked ...

  11. Electroreflectance of CuInS{sub 2}-solar cells for the optimization of the process parameters during the absorbers production process; Elektroreflexion an CuInS{sub 2}-Solarzellen im Hinblick auf die Optimierung der Prozessparameter bei der Absorber-Herstellung

    Henninger, R.

    2002-07-01

    CuInS{sub 2} thin film solar cells were prepared by a new sequential process. The quality of these layers and the conversion efficiency of the solar cells depends on the process parameters of the sequential process. Electroreflectance measurements are used to characterize these solar cells. This method is suitable to measure optical properties like band gap energy and to detect secondary phases in the vicinity of the heterojunction and defects in the semiconductor. Electroreflectance measurements of the thin film solar cells shows clearly a dependence of film growth from the process parameters copper to indium ratio and sulfurization temperature. From the correlation of electroreflectance results with photoluminescence, X-ray-diffraction and external quantum efficiency measurements a model of film growth was derived. Solar cells made from optimized CuInS{sub 2} films reach an active area efficiency of 12,5%. This is the best efficiency reported so far for this type of solar cell. (orig.) [German] Mit einem neuen sequentiellen Verfahren wurden CuInS{sub 2}-Duennfilme fuer die Solarzellen-Anwendung hergestellt. Die Qualitaet dieser Schichten und damit der Solarzellenwirkungsgrad haengen von den Prozessparametern des sequentiellen Prozesses ab. Elektroreflexion wurde als Messverfahren zur Charakterisierung der fertigen Solarzellen eingesetzt. Dieses Verfahren ist geeignet um optische Eigenschaften, wie die Bandlueckenenergie, zu bestimmen und Fremdphasen in der Naehe des pn-Ueberganges sowie Defekte im Halbleiter nachzuweisen. In Elektroreflexionsmessungen an den hergestellten Duennfilmsolarzellen zeigte sich deutlich eine Abhaengigkeit des Schichtwachstums von den Prozessparametern Kupfer-Indium-Verhaeltnis und Sulfurisierungstemperatur. Aus der Korrelation der Elektroreflexionsergebnisse mit Photolumineszenz-, Roentgenbeugungs- und Quantenausbeutemessungen wurde ein Modell zur Schichtbildung von CuInS{sub 2} abgeleitet. Solarzellen aus optimierten CuInS{sub 2

  12. High efficiency thermal to electric energy conversion using selective emitters and spectrally tuned solar cells

    Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

    1992-01-01

    Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1500 K. Depending on the nature of parasitic losses, overall thermal-to-electric conversion efficiencies greater than 20 percent are feasible.

  13. Optical materials technology for energy efficiency and solar energy conversion 7

    Granqvist, C.G.; Lampert, C.M.

    1989-01-01

    This book covers the following topics: smart window coatings; Transparent infrared reflectors; Holographic concentrators and reflectors; Solar collecting devices; Solar absorber coatings; Optical properties and durability

  14. Impedance matched thin metamaterials make metals absorbing.

    Mattiucci, N; Bloemer, M J; Aközbek, N; D'Aguanno, G

    2013-11-13

    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin ( 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others.

  15. Supersaturated Self-Assembled Charge-Selective Interfacial Layers for Organic Solar Cells

    2014-11-24

    layers (IFLs) on the tin-doped indium oxide (ITO) anodes of organic photovoltaic (OPV) cells, a series of Ar2N-(CH2)n-SiCl3 precursors with Ar = 3,4...Bulk- heterojunction OPV devices are fabricated with these SHSAMs: ITO/IFL/poly[[4,8- bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][2...phobicity,15,19,20 electrical conductivity,21−23 and charge in- jection/collection selectivity through the film.1,2,10 For example, on metal oxide substrates

  16. In situ codoping of a CuO absorber layer with aluminum and titanium: the impact of codoping and interface engineering on the performance of a CuO-based heterojunction solar cell

    Masudy-Panah, Saeid; Radhakrishnan, K.; Ru, Tan Hui; Yi, Ren; Wong, Ten It; Dalapati, Goutam Kumar

    2016-09-01

    Aluminum-doped cupric oxide (CuO:Al) was prepared via an out-diffusion process of Al from an Al-coated substrate into the deposited CuO thin film upon thermal treatment. The effect of the annealing temperature on the structural and optical properties of CuO:Al was investigated in detail. The influence of Al incorporation on the photovoltaic properties was then investigated by preparing a p-CuO:Al/n-Si heterojunction solar cell. A significant improvement in the performance of the solar cell was achieved by controlling the out-diffusion of Al. A novel in situ method to co-dope CuO with Al and titanium (Ti) has been proposed to demonstrate CuO-based solar cells with the front surface field (FSF) design. The FSF design was created by depositing a CuO:Al layer followed by a Ti-doped CuO (CuO:Ti) layer. This is the first successful experimental demonstration of the codoping of a CuO thin film and CuO thin film solar cells with the FSF design. The open circuit voltage (V oc), short circuit current density (J sc) and fill factor (FF) of the fabricated solar cells were significantly higher for the FSF device compared to devices without FSF. The FF of this device improved by 68% through the FSF design and a record efficiency ɳ of 2% was achieved. The improvement of the solar cell properties is mainly attributed to the reduction of surface recombination, which influences the charge carrier collection.

  17. Effects of annealing temperatures on the morphological, mechanical, surface chemical bonding, and solar selectivity properties of sputtered TiAlSiN thin films

    Rahman, M. Mahbubur; Jiang, Zhong-Tao; Zhou, Zhi-feng; Xie, Zonghan; Yin, Chun Yang; Kabir, Humayun; Haque, Md. Mahbubul; Amri, Amun; Mondinos, Nicholas; Altarawneh, Mohammednoor

    2016-01-01

    Quaternary sputtered TiAlSiN coatings were investigated for their high temperature structural stability, surface morphology, mechanical behaviors, surface chemical bonding states, solar absorptance and thermal emittance for possible solar selective surface applications. The TiAlSiN films were synthesized, via unbalanced magnetron sputtered technology, on AISI M2 steel substrate and annealed at 500 °C - 800 °C temperature range. SEM micrographs show nanocomposite-like structure with amorphous grain boundaries. Nanoindentation analyses indicate a decrease of hardness, plastic deformation and constant yield strength for the coatings. XPS analysis show mixed Ti, Al and Si nitride and oxide as main coating components but at 800 °C the top layer of the coatings is clearly composed of only Ti and Al oxides. Synchrotron radiation XRD (SR-XRD) results indicate various Ti, Al and Si nitride and oxide phases, for the above annealing temperature range with a phase change occurring with the Fe component of the substrate. UV–Vis spectroscopy, FTIR spectroscopy studies determined a high solar selectivity, s of 24.6 for the sample annealed at 600 °C. Overall results show good structural and morphological stability of these coatings at temperatures up to 800 °C with a very good solar selectivity for real world applications. - Highlights: • TiAlSiN sputtered coatings were characterized for solar selective applications. • In situ synchrotron radiation XRD were studies show the occurrence of multiple stable phases. • A high selectivity of 24.63 has been achieved for the coatings annealed at 700 °C. • Existence of XRD phases were also confirmed by XPS measurements. • At high temperature annealing the mechanical properties of films were governed by the utmost surfaces of the films.

  18. Solar cell with back side contacts

    Nielson, Gregory N; Okandan, Murat; Cruz-Campa, Jose Luis; Resnick, Paul J; Wanlass, Mark Woodbury; Clews, Peggy J

    2013-12-24

    A III-V solar cell is described herein that includes all back side contacts. Additionally, the positive and negative electrical contacts contact compoud semiconductor layers of the solar cell other than the absorbing layer of the solar cell. That is, the positive and negative electrical contacts contact passivating layers of the solar cell.

  19. Potential Visual Impacts of Utility-Scale Solar Energy Development within Solar Energy Zones on Selected Viewpoints in Death Valley and Joshua Tree National Parks, and El Camino Real De Tierra Adentro National Historic Trail

    Sullivan, Robert G. [Argonne National Lab. (ANL), Argonne, IL (United States); Abplanalp, Jennifer M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cantwell, Brian L. [Argonne National Lab. (ANL), Argonne, IL (United States); Beckman, Kevin J. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-06-01

    In connection with the Bureau of Land Management’s (BLM’s) Solar Programmatic Environmental Impact Statement (Solar PEIS), Argonne National Laboratory (Argonne) has conducted an extended visual impact analysis for selected key observation points (KOPs) within three National Park Service (NPS) units located within the 25-mi (40-km) viewshed of four solar energy zones (SEZs) identified in the Solar PEIS. The analysis includes only those NPS units that the Solar PEIS identified as potentially subject to moderate or strong visual contrasts associated with solar development within the SEZs. The NPS units included in the analysis are Death Valley and Joshua Tree National Parks and El Camino Real De Tierra Adentro National Historic Trail. The analysis showed that certain KOPs in each of these NPS units could potentially be subject to major visual contrast and impacts from solar development within the SEZs, but many of the KOPs would likely be subject to moderate, minor, or negligible contrasts and impacts, generally because they were relatively distant from the relevant SEZ, had views of the SEZ partially blocked by intervening terrain, and/or had very low vertical angles of view toward the SEZ. For all three NPS units, power tower facilities were found to be major contributors to potential visual contrasts, primarily because of the long-distance visibility of intensely bright reflection of light from the receivers on the central towers, but also because of the height and strong vertical line of the tower structures and the potential for night-sky impacts from FAA-mandated hazard navigation lighting.

  20. Solar Air Heaters with Thermal Heat Storages

    Saxena, Abhishek; Goel, Varun

    2013-01-01

    Solar energy can be converted into different forms of energy, either to thermal energy or to electrical energy. Solar energy is converted directly into electrical power by photovoltaic modules, while solar collector converts solar energy into thermal energy. Solar collector works by absorbing the direct solar radiation and converting it into thermal energy, which can be stored in the form of sensible heat or latent heat or a combination of sensible and latent heats. A theoretical study has be...

  1. Feasibility Study on the Use of a Solar Thermoelectric Cogenerator Comprising a Thermoelectric Module and Evacuated Tubular Collector with Parabolic Trough Concentrator

    Miao, L.; Zhang, M.; Tanemura, S.; Tanaka, T.; Kang, Y. P.; Xu, G.

    2012-06-01

    We have designed a new solar thermoelectric cogeneration system consisting of an evacuated tubular solar collector (ETSC) with a parabolic trough concentrator (PTC) and thermoelectric modules (TEMs) to supply both thermal energy and electricity. The main design concepts are (1) the hot side of the TEM is bonded to the solar selective absorber installed in an evacuated glass tube, (2) the cold side of the TEM is also bonded to the heat sink, and (3) the outer circulated water is heated by residual solar energy after TEM generation. We present an example solar thermal simulation based on energy balance and heat transfer as used in solar engineering to predict the electrical conversion efficiency and solar thermal conversion efficiency for different values of parameters such as the solar insolation, concentration ratio, and TEM ZT values.

  2. Heterogeneous neutron absorbers development

    Boccaccini, Aldo; Agueda, Horacio; Russo, Diego; Perez, Edmundo

    1987-01-01

    The use of solid burnable absorber materials in power light water reactors has increased in the last years, specially due to improvements attained in costs of generated electricity. The present work summarizes the basic studies made on an alumina-gadolinia system, where alumina is the inert matrix and gadolinia acts as burnable poison, and describes the fabrication method of pellets with that material. High density compacts were obtained in the range of concentrations used by cold pressing and sintering at 1600 deg C in inert (Ar) atmosphere. Finally, the results of the irradiation experiences made at RA-6 reactor, located at the Bariloche Atomic Center, are given where variations on negative reactivity caused by introduction of burnable poison rods were measured. The results obtained from these experiences are in good agreement with those coming from calculation codes. (Author)

  3. Solar Features - Solar Flares - Patrol

    National Oceanic and Atmospheric Administration, Department of Commerce — The H-alpha Flare Patrol identifies time periods each day when the sun is being continuously monitored by select ground-based solar observatories.

  4. Connectable solar air collectors

    Oestergaard Jensen, S.; Bosanac, M.

    2002-02-01

    The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

  5. "Supersaturated" self-assembled charge-selective interfacial layers for organic solar cells.

    Song, Charles Kiseok; Luck, Kyle A; Zhou, Nanjia; Zeng, Li; Heitzer, Henry M; Manley, Eric F; Goldman, Samuel; Chen, Lin X; Ratner, Mark A; Bedzyk, Michael J; Chang, Robert P H; Hersam, Mark C; Marks, Tobin J

    2014-12-24

    To achieve densely packed charge-selective organosilane-based interfacial layers (IFLs) on the tin-doped indium oxide (ITO) anodes of organic photovoltaic (OPV) cells, a series of Ar2N-(CH2)n-SiCl3 precursors with Ar = 3,4-difluorophenyl, n = 3, 6, 10, and 18, was synthesized, characterized, and chemisorbed on OPV anodes to serve as IFLs. To minimize lateral nonbonded -NAr2···Ar2N- repulsions which likely limit IFL packing densities in the resulting self-assembled monolayers (SAMs), precursor mixtures having both small and large n values are simultaneously deposited. These "heterogeneous" SAMs are characterized by a battery of techniques: contact angle measurements, X-ray reflectivity, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy (UPS), cyclic voltammetry, and DFT computation. It is found that the headgroup densities of these "supersaturated" heterogeneous SAMs (SHSAMs) are enhanced by as much as 17% versus their homogeneous counterparts. Supersaturation significantly modifies the IFL properties including the work function (as much as 16%) and areal dipole moment (as much as 49%). Bulk-heterojunction OPV devices are fabricated with these SHSAMs: ITO/IFL/poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][2-[[(2-ethylhexyl)oxy]carbonyl]-3-fluorothieno[3,4-b]thiophenediyl

  6. Two Fixed, Evacuated, Glass, Solar Collectors Using Nonimaging Concentration

    Garrison, John D.; Winston, Roland; O'Gallagher, Joseph; Ford, Gary

    1984-01-01

    Two fixed, evacuated, glass solar thermal collectors have been designed. The incorporation of nonimaging concentration, selective absorption and vacuum insulation into their design is essential for obtaining high efficiency through low heat loss, while operating at high temperatures. Nonimaging, approximately ideal concentration with wide acceptance angle permits solar radiation collection without tracking the sun, and insures collection of much of the diffuse radiation. It also minimizes the area of the absorbing surface, thereby reducing the radiation heat loss. Functional integration, where different parts of these two collectors serve more than one function, is also important in achieving high efficiency, and it reduces cost.

  7. Effects of the selection of heat transfer fluid and condenser type on the performance of a solar thermal power plant with technoeconomic approach

    Yilmazoglu, M. Zeki

    2016-01-01

    Highlights: • The effects of the selection of HTF and condenser type on STPs were examined. • Levelized cost of energy (LCOE) for STP was investigated. • LCOE for STP compared with gas turbine and combined cycle. • CSP with thermal storage can be competitive technology with carbon tax/credits. - Abstract: Renewable electricity generation systems have an increasing trend in terms of usage due to aiming to decrease greenhouse gas emissions and energy source diversification strategies of countries. Parabolic trough, Fresnel, and solar tower systems have been used to generate solar thermal electricity around the world. In this study, the effects of the selection of collector heat transfer fluid (HTF) and condenser type on a concentrated solar thermal power plant were analyzed. Net power, net electrical efficiency, and economic analysis were carried out for the selected HTFs for different collector outlet temperature cases. In the case of condenser type selection four different systems were considered; water cooled, air cooled (dry air) and air cooled with water spraying (spraying before fan and spraying before and after fan). Levelized cost of energy (LCOE) and specific investment cost were calculated. According to the results, specific investment cost and LCOE were found to be 4000 USD/kW_e_l and 0.207 USD/kW h, respectively. Carbon tax/credit was also included to the calculations of LCOE and a comparison study was carried out for gas turbine, combined cycle and solar thermal power plant with thermal storage. Including carbon tax/credit to the LCOE shows that solar thermal power plant with heat storage can be competitive when compared to gas turbines.

  8. Interpolating and Estimating Horizontal Diffuse Solar Irradiation to Provide UK-Wide Coverage: Selection of the Best Performing Models

    Diane Palmer

    2017-02-01

    Full Text Available Plane-of-array (PoA irradiation data is a requirement to simulate the energetic performance of photovoltaic devices (PVs. Normally, solar data is only available as global horizontal irradiation, for a limited number of locations, and typically in hourly time resolution. One approach to handling this restricted data is to enhance it initially by interpolation to the location of interest; next, it must be translated to PoA data by separately considering the diffuse and the beam components. There are many methods of interpolation. This research selects ordinary kriging as the best performing technique by studying mathematical properties, experimentation and leave-one-out-cross validation. Likewise, a number of different translation models has been developed, most of them parameterised for specific measurement setups and locations. The work presented identifies the optimum approach for the UK on a national scale. The global horizontal irradiation will be split into its constituent parts. Divers separation models were tried. The results of each separation algorithm were checked against measured data distributed across the UK. It became apparent that while there is little difference between procedures (14 Wh/m2 mean bias error (MBE, 12 Wh/m2 root mean square error (RMSE, the Ridley, Boland, Lauret equation (a universal split algorithm consistently performed well. The combined interpolation/separation RMSE is 86 Wh/m2.

  9. Effects of Sheet Resistance on mc-Si Selective Emitter Solar Cells Using Laser Opening and One-Step Diffusion

    Sheng-Shih Wang

    2015-01-01

    Full Text Available In order to simplify process procedure and improve conversion efficiency (η, we present new steps of laser opening and one-step POCl3 diffusion to fabricate selective emitter (SE solar cells, in which heavily doped regions (HDR and lightly doped regions (LDR were formed simultaneously. For HDR, we divided six cells into two groups for POCl3 diffusion with sheet resistance (RS of 40 Ω/sq (for group A and 50 Ω/sq (for group B. The dry oxidation duration at a temperature of 850°C was 18, 25, and 35 min for the 3 different cells in each group. This created six SE samples with different RS pairings for the HDR and LDR. The optimal cell (sample SE2 with RS values of 40/81 Ω/Sq in HDR/LDR showed the best η of 16.20%, open circuit voltage (VOC of 612.52 mV, and fill factor (FF of 75.83%. The improvement ratios are 1.57% for η and 14.32% for external quantum efficiency (EQE as compared with those of the two-step diffusion process of our previous study. Moreover, the one-step laser opening process and omitting the step of removing the damage caused by laser ablation especially reduce chemistry pollution, thus showing ecofriendly process for use in industrial-scale production.

  10. Design, Fabrication and Characterization of MIM Diodes and Frequency Selective Thermal Emitters for Solar Energy Harvesting and Detection Devices

    Sharma, Saumya

    could be achieved in this case. These long chain polymeric molecules exhibit a two-dimensional molecular assembly thereby reducing the tunneling distance between the metal electrodes on either side of the insulating layer. Rectification ratios as high as 450:1 at +/-200mV were obtained for an MIM diode configuration of Ni-LB films of Arachidic Acid films-(Au/Pd). The bandwidth of the incident radiation that can be used by this rectenna assembly is limited to 9.5% of 30THz or +/-1.5THz from the center frequency based on the antenna designs which were proposed for this research. This bandwidth constraint has led to research in the field of frequency selective emitters capable of providing a narrowband emission around 30THz. Several grating structures were fabricated in the form of Ni-Si periodic arrays, in a cleanroom environment using photolithography, sputtering and deep reactive ion etching. These frequency selective samples were characterized with the help of focusing optics, monochromators and HgCdTe detectors. The results obtained from the emission spectra were utilized to calibrate a simulation model with Computer Simulation Technology (CST) which uses numerous robust solving techniques, such as the finite element method, in order to obtain the optical parameters for the model. Thereafter, a thorough analysis of the different dimensional and material parameters was performed, to understand their dependence on the emissivity of the selective emitter. Further research on the frequency selectivity of the periodic nano-disk or nano-hole array led to the temperature dependence of the simulated spectra, because the material parameters, such as refractive index or drude model collision frequency, vary with temperature. Thus, the design of frequency selective absorbers/emitters was found to be significantly affected with temperature range of operation of these structures.

  11. Reflection measurements of microwave absorbers

    Baker, Dirk E.; van der Neut, Cornelis A.

    1988-12-01

    A swept-frequency interferometer is described for making rapid, real-time assessments of localized inhomogeneities in planar microwave absorber panels. An aperture-matched exponential horn is used to reduce residual reflections in the system to about -37 dB. This residual reflection is adequate for making comparative measurements on planar absorber panels whose reflectivities usually fall in the -15 to -25 dB range. Reflectivity measurements on a variety of planar absorber panels show that multilayer Jaumann absorbers have the greatest inhomogeneity, while honeycomb absorbers generally have excellent homogeneity within a sheet and from sheet to sheet. The test setup is also used to measure the center frequencies of resonant absorbers. With directional couplers and aperture-matched exponential horns, the technique can be easily applied in the standard 2 to 40 GHz waveguide bands.

  12. Aperiodic-metamaterial-based absorber

    Quanlong Yang

    2017-09-01

    Full Text Available The periodic-metamaterial-based perfect absorber has been studied broadly. Conversely, if the unit cell in the metamaterial-based absorber is arranged aperiodically (aperiodic-metamaterial-based absorber, how does it perform? Inspired by this, here we present a systematic study of the aperiodic-metamaterial-based absorber. By investigating the response of metamaterial absorbers based on periodic, Fibonacci, Thue-Morse, and quasicrystal lattices, we found that aperiodic-metamaterial-based absorbers could display similar absorption behaviors as the periodic one in one hand. However, their absorption behaviors show different tendency depending on the thicknesses of the spacer. Further studies on the angle and polarization dependence of the absorption behavior are also presented.

  13. Fabrication and characterization of absorber pellets for FFTF irradiation testing

    Wilson, C.N.; Hollenberg, G.W.

    1981-01-01

    Methods used for characterization of B 4 C powder and fabricated pellets are summarized. Fabrication techniques used at HEDL for absorber test pellets are reviewed and selected powder and pellet characterization data are presented

  14. Liquid absorbent solutions for separating nitrogen from natural gas

    Friesen, Dwayne T.; Babcock, Walter C.; Edlund, David J.; Lyon, David K.; Miller, Warren K.

    2000-01-01

    Nitrogen-absorbing and -desorbing compositions, novel ligands and transition metal complexes, and methods of using the same, which are useful for the selective separation of nitrogen from other gases, especially natural gas.

  15. Optimal Site Selection of Wind-Solar Complementary Power Generation Project for a Large-Scale Plug-In Charging Station

    Wenjun Chen

    2017-10-01

    Full Text Available The wind-solar hybrid power generation project combined with electric vehicle charging stations can effectively reduce the impact on the power system caused by the random charging of electric cars, contribute to the in-situ wind-solar complementary system and reduce the harm arising from its output volatility. In this paper, the site selection index system of a landscape complementary power generation project is established by using the statistical methods and statistical analysis in the literature. Subsequently, using the Analytic Network Process to calculate the index weight, a cloud model was used in combination with preference ranking organization method for enrichment evaluations to transform and sort uncertain language information. Finally, using the results of the decision-making for the location of the Shanghai wind-solar complementary project and by carrying out contrast analysis and sensitivity analysis, the superiority and stability of the decision model constructed in this study was demonstrated.

  16. Solar constant values for estimating solar radiation

    Li, Huashan; Lian, Yongwang; Wang, Xianlong; Ma, Weibin; Zhao, Liang

    2011-01-01

    There are many solar constant values given and adopted by researchers, leading to confusion in estimating solar radiation. In this study, some solar constant values collected from literature for estimating solar radiation with the Angstroem-Prescott correlation are tested in China using the measured data between 1971 and 2000. According to the ranking method based on the t-statistic, a strategy to select the best solar constant value for estimating the monthly average daily global solar radiation with the Angstroem-Prescott correlation is proposed. -- Research highlights: → The effect of the solar constant on estimating solar radiation is investigated. → The investigation covers a diverse range of climate and geography in China. → A strategy to select the best solar constant for estimating radiation is proposed.

  17. Studies of flat-plate solar air collectors with absorber plates made of amorphous silicon photovoltaic modules; Amorphous taiyo denchi module wo shunetsuban to shita heibangata kukishiki shunetsuki no kenkyu

    Sato, K; Ito, S; Miura, N [Kanagawa Institute of Technology, Kanagawa (Japan)

    1996-10-27

    A light/heat hybrid air type heat collector has been developed in which heat is collected by solar cell panels. In Type 1 heat collector provided with a glass cover, two modules are connected in series and placed under a glass cover to serve as a heat collecting plate, each module built of a steel plate and two thin-film amorphous solar cells bonded to the steel plate. Air runs under the heat collecting plate. Type 2 heat collector is a Type 1 heat collector minus the glass cover. Air is taken in by a fan, runs in a vinyl chloride tube, and then through the heat collector where it is heated by the sun, and goes out at the exit. Heat collecting performance was subjected to theoretical analysis. This heat collector approximated in point of heat collection a model using a board painted black, which means that the new type functions effectively as an air-type heat collector. Operating as a photovoltaic power generator, the covered type generated approximately 20% less than the uncovered type under 800W/m{sup 2} insolation conditions. Type 1 has been in service for five months, and Type 2 for 2 months. At present, both are free of troubles such as deformation and the amorphous solar cell modules have deteriorated but a little. 4 refs., 9 figs.

  18. Experimental study of multipurpose solar hot box at Freiburg, Germany

    Nandwani, S.S. [Iowa State University, Ames (United States). International Inst. of Theoretical and Applied Physics; Steinhart, J.; Henning, H.M.; Rommel, M.; Wittwer, V. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany)

    1997-12-31

    With the aim to test an compare some properties of materials and common geometries that are used for designing solar cookers, water heaters, etc. we have made a solar hot box with two similar compartments. In the present study this hot box has been used for, (a) comparing the behavior of a metallic slab filled with a phase change material for short term heat storage, with a conventional absorbing sheet, (b) the use of a selectively coated, as compared to a normal black painted, cooking pot, and (c) for finding the overall heat loss coefficient and thermal capacity of the box. Experiments with the solar hot box will yield valuable information on solar systems that are to be constructed. Besides its use for research this multi-purpose device has been used both to pasteurize up to 14-16 l of water and for cooking. (author)

  19. Selected Contributions of the 4th European Meeting on Solar Chemistry and Photocatalysis. Environmental Applications (SPEA 4)

    Malato Rodriguez, S.; Gernjak, W.; Pereze Pena, J.; Dona Rodriguez, J.M.

    2007-01-01

    In developed countries, the importance of water as a resource and problems derived from its scarcity has led to growing social and legislative demands. As a consequence, in the last 30 years, new fields of research have opened in a search for more efficient water treatment methods. This is the case of the advanced oxidation techniques (AOTs) and their application to nonbiodegradable contaminants, which can otherwise be removed from water, but not eliminated. Fast development of research in this field has encouraged chemists, chemical engineers and related professionals to meet and debate their findings and plan new strategies for the future, working toward evermore efficient methods of wastewater treatment wherever needed. The same can be said of gaseous effluents, as emission limits for organic air pollution become stricter. Volatile organic compounds (VOCs) pose an environmental and health threat, which can be treated by adsorption, incineration, condensation, etc., or be completely destroyed by chemical methods, such as the very promising gas-phase photocatalytic air pollution treatment. The SPEA Meetings have been held against this background, particularly this fourth one, where scientists assembled to present and debate their latest achievements in low-cost treatment technologies for wastewater, gaseous effluents and polluted soils. This Special Issue of Catalysis Today was compiled from the scientific reports generated by the congress, and includes a selection of some of the most interesting work presented at the meeting. The 34-member Scientific Committee were from 11 different countries (Argentina, Chile, Finland, France, Germany, Greece, Italy, Slovakia, Spain, Switzerland, and the USA). One hundred and thirty-five delegates from 22 different countries attended the congress (representing 368 authors). One hundred and thirty-eight communications were presented, 45 oral presentations and 93 posters. Three plenary lectures, one round table and two poster

  20. Design, Construction and Performance Comparison of Two Solar ...

    Productivity enhancement of solar stills has been one of the main goals of researchers. In this study, two designs of solar stills absorber plate were conceptualized and developed and their effects on the productivity process were investigated experimentally. A solar still using a submerged flat absorber plate and another ...