WorldWideScience

Sample records for absorbers solar

  1. Solar radiation absorbing material

    Science.gov (United States)

    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.

  2. Solar energy utilization by solar cells and superblack absorbers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Microstructured extremely thin absorber solar cells

    DEFF Research Database (Denmark)

    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...

  4. Fabrication of high efficacy selective solar absorbers

    CSIR Research Space (South Africa)

    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...

  5. Performance of an absorbing concentrating solar collectors

    International Nuclear Information System (INIS)

    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

  6. Development of an innovative solar absorber

    Science.gov (United States)

    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.

  7. Fabrication of selective solar absorbers using pulsed laser deposition

    CSIR Research Space (South Africa)

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Robust optimization of a tandem grating solar thermal absorber

    Science.gov (United States)

    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.

  10. Selective solar absorber emittance measurement at elevated temperature

    Science.gov (United States)

    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.

  11. Characterization of selective solar absorber under high vacuum.

    Science.gov (United States)

    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.

  12. Energy Analysis of Solar Collector With perforated Absorber Plate

    Directory of Open Access Journals (Sweden)

    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.

  13. Absorber design for a Scheffler-Type Solar Concentrator

    International Nuclear Information System (INIS)

    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

  14. Development of CIGS2 solar cells with lower absorber thickness

    Energy Technology Data Exchange (ETDEWEB)

    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)

  15. High temperature solar energy absorbing surfaces

    Science.gov (United States)

    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.

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

    CSIR Research Space (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...

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  19. A high absorbance material for solar collectors' applications

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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

    Directory of Open Access Journals (Sweden)

    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

    OpenAIRE

    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.

    Energy Technology Data Exchange (ETDEWEB)

    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

    Energy Technology Data Exchange (ETDEWEB)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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%.

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

    International Nuclear Information System (INIS)

    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%.

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

    OpenAIRE

    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...

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

    OpenAIRE

    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) ...

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

    DEFF Research Database (Denmark)

    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...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    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...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    OpenAIRE

    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 ...

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    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...

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

    CSIR Research Space (South Africa)

    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...

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    NARCIS (Netherlands)

    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

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

    CSIR Research Space (South Africa)

    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...

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    DEFF Research Database (Denmark)

    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...

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    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

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

    CSIR Research Space (South 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

  9. The CVD ZrB2 as a selective solar absorber

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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)

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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”.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    International Nuclear Information System (INIS)

    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.)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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 %.

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

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    KAUST Repository

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  16. XPS and SIMS characterisation of TiOxNy solar absorber films

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    DEFF Research Database (Denmark)

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    DEFF Research Database (Denmark)

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    International Nuclear Information System (INIS)

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    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...

  10. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

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

    International Nuclear Information System (INIS)

    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.

  3. 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

    Science.gov (United States)

    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%.

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

    CSIR Research Space (South Africa)

    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...

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

    KAUST Repository

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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.

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

    KAUST Repository

    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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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%.

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    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.

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

    CSIR Research Space (South Africa)

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    International Nuclear Information System (INIS)

    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

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

    DEFF Research Database (Denmark)

    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...

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

    KAUST Repository

    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.

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

    KAUST Repository

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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%.

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

    NARCIS (Netherlands)

    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

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

    CSIR Research Space (South Africa)

    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...

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

    CSIR Research Space (South Africa)

    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...

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

    CSIR Research Space (South Africa)

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  19. Solar energy collector

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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.

  2. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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).

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

    Science.gov (United States)

    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.

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

    Data.gov (United States)

    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...

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

    Data.gov (United States)

    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...

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  10. Shock absorber

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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.

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

    NARCIS (Netherlands)

    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

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

    Science.gov (United States)

    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.

  14. 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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. 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

    International Nuclear Information System (INIS)

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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%.

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

    Science.gov (United States)

    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.

  8. Absorbant materials

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  12. PERFORMANCE EVALUATION OF SOLAR COLLECTORS USING A SOLAR SIMULATOR

    OpenAIRE

    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...

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Sound Absorbers

    Science.gov (United States)

    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

    Energy Technology Data Exchange (ETDEWEB)

    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

    Energy Technology Data Exchange (ETDEWEB)

    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. 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

    International Nuclear Information System (INIS)

    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)

  20. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Shock absorber

    International Nuclear Information System (INIS)

    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)

  2. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Visible light broadband perfect absorbers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Science.gov (United States)

    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.

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

    NARCIS (Netherlands)

    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

  7. Effect of band-aligned double absorber layers on photovoltaic characteristics of chemical bath deposited PbS/CdS thin film solar cells.

    Science.gov (United States)

    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.

  8. Single and multijunction silicon based thin film solar cells on a flexible substrate with absorber layers made by hot-wire CVD

    Science.gov (United States)

    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

  9. Bismuth-doped Cu(In,Ga)Se{sub 2} absorber prepared by multi-layer precursor method and its solar cell

    Energy Technology Data Exchange (ETDEWEB)

    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)

  10. Bismuth-doped Cu(In,Ga)Se2 absorber prepared by multi-layer precursor method and its solar cell

    International Nuclear Information System (INIS)

    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)

  11. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. PERFORMANCE EVALUATION OF SOLAR COLLECTORS USING A SOLAR SIMULATOR

    Directory of Open Access Journals (Sweden)

    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 

  13. Low band gap S,N-heteroacene-based oligothiophenes as hole-transporting and light absorbing materials for efficient perovskite-based solar cells

    KAUST Repository

    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.

  14. Low band gap S,N-heteroacene-based oligothiophenes as hole-transporting and light absorbing materials for efficient perovskite-based solar cells

    KAUST Repository

    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.

  15. Photoluminescence of polycrystalline CuInS{sub 2} absorber layers and solar cells; Photolumineszenz an polykristallinen CuInS{sub 2}-Absorberschichten und Solarzellen

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Modification of electron states in CdTe absorber due to a buffer layer in CdTe/CdS solar cells

    International Nuclear Information System (INIS)

    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

  17. Modification of electron states in CdTe absorber due to a buffer layer in CdTe/CdS solar cells

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. The crystallisation of Cu2ZnSnS4 thin film solar cell absorbers from co-electroplated Cu-Zn-Sn precursors

    International Nuclear Information System (INIS)

    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

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

    OpenAIRE

    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...

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

    OpenAIRE

    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...

  1. Solar Energy Technician/Installer

    Science.gov (United States)

    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…

  2. The crystallisation of Cu{sub 2}ZnSnS{sub 4} thin film solar cell absorbers from co-electroplated Cu-Zn-Sn precursors

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Shock absorbing structure

    International Nuclear Information System (INIS)

    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.)

  4. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se2 thin-film solar cell absorbers

    Science.gov (United States)

    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.

  5. Spectrally-engineered solar thermal photovoltaic devices

    Science.gov (United States)

    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.

  6. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se{sub 2} thin-film solar cell absorbers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Absorbance and fluorescence studies on porphyrin Nanostructures ...

    African Journals Online (AJOL)

    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 ...

  8. Methods for absorbing neutrons

    Science.gov (United States)

    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.

  9. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Hydraulic shock absorbers

    International Nuclear Information System (INIS)

    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

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

    CSIR Research Space (South Africa)

    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...

  12. Optimization of Perfect Absorbers with Multilayer Structures

    Science.gov (United States)

    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.

  13. PWR burnable absorber evaluation

    International Nuclear Information System (INIS)

    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)

  14. TOMS Absorbing Aerosol Index

    Data.gov (United States)

    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...

  15. 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

    International Nuclear Information System (INIS)

    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.

  16. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Neutron absorbing article

    International Nuclear Information System (INIS)

    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

  18. Burnable neutron absorbers

    International Nuclear Information System (INIS)

    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

  19. Mechanical shock absorber

    International Nuclear Information System (INIS)

    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

  20. Neutron absorbing article

    International Nuclear Information System (INIS)

    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

  1. Solar heating pipe

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  3. Low Absorbance Measurements

    Science.gov (United States)

    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.

  4. Solar electricity and solar fuels

    Science.gov (United States)

    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.

  5. Adjustable Shock Absorbers

    OpenAIRE

    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...

  6. Kinetic energy absorbing pad

    International Nuclear Information System (INIS)

    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.)

  7. Absorbable and biodegradable polymers

    CERN Document Server

    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

  8. A novel design for a cheap high temperature solar collector: The rotating solar boiler

    NARCIS (Netherlands)

    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

  9. Burnable neutron absorbers

    International Nuclear Information System (INIS)

    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

  10. Shock absorber in Ignalina NPP

    International Nuclear Information System (INIS)

    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

  11. Absorber for terahertz radiation management

    Science.gov (United States)

    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.

  12. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    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.

  13. Feynman Integrals with Absorbing Boundaries

    OpenAIRE

    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 ...

  14. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

  15. Optical materials technology for energy efficiency and solar energy conversion 7

    International Nuclear Information System (INIS)

    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

  16. Impedance matched thin metamaterials make metals absorbing.

    Science.gov (United States)

    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.

  17. 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

    Science.gov (United States)

    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.

  18. Solar cell with back side contacts

    Science.gov (United States)

    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. Solar Air Heaters with Thermal Heat Storages

    OpenAIRE

    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...

  20. Metamaterial electromagnetic wave absorbers.

    Science.gov (United States)

    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.

  1. Heterogeneous neutron absorbers development

    International Nuclear Information System (INIS)

    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)

  2. Connectable solar air collectors

    Energy Technology Data Exchange (ETDEWEB)

    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

  3. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

  4. Reflection measurements of microwave absorbers

    Science.gov (United States)

    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.

  5. Aperiodic-metamaterial-based absorber

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Design, Construction and Performance Comparison of Two Solar ...

    African Journals Online (AJOL)

    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 ...

  8. Neutron absorbing element

    International Nuclear Information System (INIS)

    Kasai, Shigeo.

    1991-01-01

    The present invention concerns a neutron absorbing element of a neutron shielding member used for an LMFBR type reactor. The inside of a fuel can sealed at both of the upper and the lower ends thereof with plugs is partitioned into an upper and a lower chambers by an intermediate plug. A discharging hole is disposed at the upper end plug, which is in communication with the outside. A communication tube is disposed at the intermediate end plug and it is in communication with the lower chamber containing B 4 C pellets. A cylindrical support member having three porous plugs connected in series is disposed at the lower surface of the discharging hole provided at the upper end plug. Further, the end of the discharging hole is sealed with high temperature solder and He atmosphere is present at the inside of the fuel can. With such a constitution, the supporting differential pressure of the porous plugs can be made greater while discharging He gases generated from B 4 C to the outside. Further, the porous plugs can be surely wetted by coolants. Accordingly, it is possible to increase life time and shorten the size. (I.N.)

  9. Light-absorbing carbon from prescribed and laboratory biomass burning and gasoline vehicle emissions

    Science.gov (United States)

    Carbonaceous aerosols are ubiquitous in the atmosphere and can directly affect Earth’s climate by absorbing and scattering incoming solar radiation. Both field and laboratory measurements have confirmed that biomass burning (BB) is an important primary source of light absorbing o...

  10. Burnable absorber coated nuclear fuel

    International Nuclear Information System (INIS)

    Chubb, W.; Radford, K.C.; Parks, B.H.

    1984-01-01

    A nuclear fuel body which is at least partially covered by a burnable neutron absorber layer is provided with a hydrophobic overcoat generally covering the burnable absorber layer and bonded directly to it. In a method for providing a UO 2 fuel pellet with a zirconium diboride burnable poison layer, the fuel body is provided with an intermediate niobium layer. (author)

  11. Porphyrin Based Near Infrared-Absorbing Materials for Organic Photovoltaics

    Science.gov (United States)

    Zhong, Qiwen

    The conservation and transformation of energy is essential to the survival of mankind, and thus concerns every modern society. Solar energy, as an everlasting source of energy, holds one of the key solutions to some of the most urgent problems the world now faces, such as global warming and the oil crisis. Advances in technologies utilizing clean, abundant solar energy, could be the steering wheel of our societies. Solar cells, one of the major advances in converting solar energy into electricity, are now capturing people's interest all over the globe. While solar cells have been commercially available for many years, the manufacturing of solar cells is quite expensive, limiting their broad based implementation. The cost of solar cell based electricity is 15-50 cents per kilowatt hour (¢/kwh), depending on the type of solar cell, compared to 0.7 ¢/kwh for fossil fuel based electricity. Clearly, decreasing the cost of electricity from solar cells is critical for their wide spread deployment. This will require a decrease in the cost of light absorbing materials and material processing used in fabricating the cells. Organic photovoltaics (OPVs) utilize organic materials such as polymers and small molecules. These devices have the advantage of being flexible and lower cost than conventional solar cells built from inorganic semiconductors (e.g. silicon). The low cost of OPVs is tied to lower materials and fabrication costs of organic cells. However, the current power conversion efficiencies of OPVs are still below 15%, while convention crystalline Si cells have efficiencies of 20-25%. A key limitation in OPVs today is their inability to utilize the near infrared (NIR) portion of the solar spectrum. This part of the spectrum comprises nearly half of the energy in sunlight that could be used to make electricity. The first and foremost step in conversion solar energy conversion is the absorption of light, which nature has provided us optimal model of, which is

  12. Leaf absorbance and photosynthesis

    Science.gov (United States)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  13. Absorbing rods for nuclear fast neutron reactor absorbing assembly

    International Nuclear Information System (INIS)

    Aji, M.; Ballagny, A.; Haze, R.

    1986-01-01

    The invention proposes a neutron absorber rod for neutron absorber assembly of a fast neutron reactor. The assembly comprises a bundle of vertical rods, each one comprising a stack of pellets made of a neutron absorber material contained in a long metallic casing with a certain radial play with regard to this casing; this casing includes traps for splinters from the pellets which may appear during reactor operation, at the level of contact between adjacent pellets. The present invention prevents the casing from rupture involved by the disintegration of the pellets producing pieces of boron carbide of high hardness [fr

  14. Solar reflector

    Energy Technology Data Exchange (ETDEWEB)

    Dvorak, J

    1983-01-15

    The reflector in the form of part of a cylindrical surface delimited by two envelopes is installed on a platform which can move on an inclined curvilinear path. The angle of inclination of the path depends on the latitude of the locality. The reflected rays are focused on the tubular absorber. One of the axes of the platform is linked to a brake controlled by a sensor for intensity of solar radiation. The sensor is a pipe filled with liquid with high value of the temperature expansion coefficient, for example alcohol. The pipe is insulated from one side and is accessible to the solar rays from the opposite. One end of the pipe is equipped with a bending end or piston. In order to expand the fluid in the sensor, the pipe acts on the brake, and the reflector is installed in a position corresponding to the maximum radiation intensity.

  15. Structural analysis of co-evaporated In{sub 2}S{sub 3} and In{sub 2}S{sub 3}:V for solar cell absorber applications

    Energy Technology Data Exchange (ETDEWEB)

    Waegele, Leonard A.; Rata, Diana; Scheer, Roland [Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle (Saale) (Germany); Gurieva, Galina [Department Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)

    2017-06-15

    In this study we use co-evaporation to grow In{sub 2}S{sub 3} thin films on glass substrates and X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to analyse the structural properties of annealed In{sub 2}S{sub 3} and V-doped In{sub 2}S{sub 3} for intermediate band solar cell application. We find co-evaporated In{sub 2}S{sub 3} to be polycrystalline on float glass and with improved crystallinity after annealing in S-atmosphere. We confirm that excessive incorporation of vanadium into the host structure is possible without formation of secondary crystalline phases. The analysis indicates a reduced crystalline quality after V doping. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Dye solar cells: a different approach to solar energy

    CSIR Research Space (South Africa)

    Le Roux, Lukas J

    2008-11-01

    Full Text Available An attractive and cheaper alternative to siliconbased photovoltaic (PV) cells for the conversion of solar light into electrical energy is to utilise dyeadsorbed, large-band-gap metal oxide materials such as TiO2 to absorb the solar light...

  17. Photoelectron antibunching and absorber theory

    International Nuclear Information System (INIS)

    Pegg, D.T.

    1980-01-01

    The recently detected photoelectron antibunching effect is considered to be evidence for the quantised electromagnetic field, i.e. for the existence of photons. Direct-action quantum absorber theory, on the other hand, has been developed on the basis that the quantised field is illusory, with quantisation being required only for atoms. In this paper it is shown that photoelectron antibunching is readily explicable in terms of absorber theory and in fact is directly attributable to the quantum nature of the emitting and detecting atoms alone. The physical nature of the reduction of the wavepacket associated with the detection process is briefly discussed in terms of absorber theory. (author)

  18. Liquid metal reactor absorber technology

    International Nuclear Information System (INIS)

    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

  19. Energy from solar balloons

    Energy Technology Data Exchange (ETDEWEB)

    Grena, Roberto [C. R. Casaccia, via Anguillarese 301, 00123 Roma (Italy)

    2010-04-15

    Solar balloons are hot air balloons in which the air is heated directly by the sun, by means of a black absorber. The lift force of a tethered solar balloon can be used to produce energy by activating a generator during the ascending motion of the balloon. The hot air is then discharged when the balloon reaches a predefined maximum height. A preliminary study is presented, along with an efficiency estimation and some considerations on possible realistic configurations. (author)

  20. Fixture for assembling solar panels

    Science.gov (United States)

    Dillard, P. A.; Fritz, W. M.

    1979-01-01

    Vacuum fixture attaches array of silicon solar cells to mounting plate made of clear glass which holds and protects cells. Glass plate transmits, rather than absorbs, solar energy thus cooling cells for efficient operation. Device therefore reduces handling of cells and interconnecting conductors to one operation.

  1. Solids-based concentrated solar power receiver

    Science.gov (United States)

    None

    2018-04-10

    A concentrated solar power (CSP) system includes channels arranged to convey a flowing solids medium descending under gravity. The channels form a light-absorbing surface configured to absorb solar flux from a heliostat field. The channels may be independently supported, for example by suspension, and gaps between the channels are sized to accommodate thermal expansion. The light absorbing surface may be sloped so that the inside surfaces of the channels proximate to the light absorbing surface define downward-slanting channel floors, and the flowing solids medium flows along these floors. Baffles may be disposed inside the channels and oriented across the direction of descent of the flowing solids medium. The channels may include wedge-shaped walls forming the light-absorbing surface and defining multiple-reflection light paths for solar flux from the heliostat field incident on the light-absorbing surface.

  2. Solar Energy - An Option for Future Energy Production

    Science.gov (United States)

    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)

  3. Colloidal quantum dot solar cells exploiting hierarchical structuring

    KAUST Repository

    Labelle, André J.; Thon, Susanna; Masala, Silvia; Adachi, Michael M.; Dong, Haopeng; Farahani, Maryam; Ip, Alexander H.; Fratalocchi, Andrea; Sargent, E. H.

    2015-01-01

    Extremely thin-absorber solar cells offer low materials utilization and simplified manufacture but require improved means to enhance photon absorption in the active layer. Here, we report enhanced-absorption colloidal quantum dot (CQD) solar cells

  4. Comparative Study of Antireflection Coating Materials for Solar ...

    African Journals Online (AJOL)

    yaog

    2017-01-17

    Jan 17, 2017 ... Locally available absorber and antireflection coating materials for ... However, a black painted steel sheet metal costs less and is readily available in local ..... Testing of a new solar coating for solar water heating applications.

  5. A checkerboard selective absorber with excellent spectral selectivity

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Solar air heaters and their applications

    Science.gov (United States)

    Selcuk, M. K.

    1977-01-01

    The solar air heater appears to be the most logical choice, as far as the ultimate application of heating air to maintain a comfortable environment is concerned. One disadvantage of solar air heaters is the need for handling larger volumes of air than liquids due to the low density of air as a working substance. Another disadvantage is the low thermal capacity of air. In cases where thermal storage is needed, water is superior to air. Design variations of solar air heaters are discussed along with the calculation of the efficiency of a flat plate solar air heater, the performance of various collector types, and the applications of solar air heaters. Attention is given to collectors with nonporous absorber plates, collectors with porous absorbers, the performance of flat plate collectors with finned absorbers, a wire mesh absorber, and an overlapped glass plate air heater.

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

    OpenAIRE

    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...

  8. Absorber materials in CANDU PHWR's

    International Nuclear Information System (INIS)

    Price, E.G.; Boss, C.R.; Novak, W.Z.; Fong, R.W.L.

    1995-03-01

    In a CANDU reactor the fuel channels are arranged on a square lattice in a calandria filled with heavy water moderator. This arrangement allows five types of tubular neutron absorber devices to be located in a relatively benign environment of low pressure, low temperature heavy water between neighbouring rows of columns of fuel channels. This paper will describe the roles of the devices and outline the design requirements of the absorber component from a reactor physics viewpoint. Nuclear heating and activation problems associated with the different absorbers will be briefly discussed. The design and manufacture of the devices will be also discussed. The control rod absorbers and shut off materials are cadmium and stainless steel. In the tubular arrangement, the cadmium is sandwiched between stainless steel tubes. This type of device has functioned well, but there is now concern over the availability and expense of cadmium which is used in two types of CANDU control devices. There are also concerns about the toxicity of cadmium during the fabrication of the absorbers. These concerns are prompting AECL to study alternatives. To minimize design changes, pure boron-10 alloyed in stainless steel is a favoured option. Work is underway to confirm the suitability of the boron-loaded steel and identify other encapsulated absorber materials for practical application. Because the reactivity devices or their guide tubes span the calandria vessel, the long slender components must be sufficiently rigid to resist operational vibration and also be seismically stable. Some of these components are made of Zircaloy to minimize neutron absorption. Slow irradiation growth and creep can reduce the spring tension, and periodic adjustments to the springs are required. Experience with the control absorber devices has generally been good. In one instance liquid zone controllers had a problem of vibration induced fretting but a designed back-fit resolved the problem. (author). 3 refs., 1

  9. Additive manufacturing of RF absorbers

    Science.gov (United States)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  10. Solar Hot Water Heater

    Science.gov (United States)

    1978-01-01

    The solar panels pictured below, mounted on a Moscow, Idaho home, are part of a domestic hot water heating system capable of providing up to 100 percent of home or small business hot water needs. Produced by Lennox Industries Inc., Marshalltown, Iowa, the panels are commercial versions of a collector co-developed by NASA. In an effort to conserve energy, NASA has installed solar collectors at a number of its own facilities and is conducting research to develop the most efficient systems. Lewis Research Center teamed with Honeywell Inc., Minneapolis, Minnesota to develop the flat plate collector shown. Key to the collector's efficiency is black chrome coating on the plate developed for use on spacecraft solar cells, the coating prevents sun heat from "reradiating," or escaping outward. The design proved the most effective heat absorber among 23 different types of collectors evaluated in a Lewis test program. The Lennox solar domestic hot water heating system has three main components: the array of collectors, a "solar module" (blue unit pictured) and a conventional water heater. A fluid-ethylene glycol and water-is circulated through the collectors to absorb solar heat. The fluid is then piped to a double-walled jacket around a water tank within the solar module.

  11. A new laboratory-scale experimental facility for detailed aerothermal characterizations of volumetric absorbers

    Science.gov (United States)

    Gomez-Garcia, Fabrisio; Santiago, Sergio; Luque, Salvador; Romero, Manuel; Gonzalez-Aguilar, Jose

    2016-05-01

    This paper describes a new modular laboratory-scale experimental facility that was designed to conduct detailed aerothermal characterizations of volumetric absorbers for use in concentrating solar power plants. Absorbers are generally considered to be the element with the highest potential for efficiency gains in solar thermal energy systems. The configu-ration of volumetric absorbers enables concentrated solar radiation to penetrate deep into their solid structure, where it is progressively absorbed, prior to being transferred by convection to a working fluid flowing through the structure. Current design trends towards higher absorber outlet temperatures have led to the use of complex intricate geometries in novel ceramic and metallic elements to maximize the temperature deep inside the structure (thus reducing thermal emission losses at the front surface and increasing efficiency). Although numerical models simulate the conjugate heat transfer mechanisms along volumetric absorbers, they lack, in many cases, the accuracy that is required for precise aerothermal validations. The present work aims to aid this objective by the design, development, commissioning and operation of a new experimental facility which consists of a 7 kWe (1.2 kWth) high flux solar simulator, a radiation homogenizer, inlet and outlet collector modules and a working section that can accommodate volumetric absorbers up to 80 mm × 80 mm in cross-sectional area. Experimental measurements conducted in the facility include absorber solid temperature distributions along its depth, inlet and outlet air temperatures, air mass flow rate and pressure drop, incident radiative heat flux, and overall thermal efficiency. In addition, two windows allow for the direct visualization of the front and rear absorber surfaces, thus enabling full-coverage surface temperature measurements by thermal imaging cameras. This paper presents the results from the aerothermal characterization of a siliconized silicon

  12. Adaptive inertial shock-absorber

    International Nuclear Information System (INIS)

    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)

  13. Thin film solar cells by selenization sulfurization using diethyl selenium as a selenium precursor

    Science.gov (United States)

    Dhere, Neelkanth G.; Kadam, Ankur A.

    2009-12-15

    A method of forming a CIGSS absorber layer includes the steps of providing a metal precursor, and selenizing the metal precursor using diethyl selenium to form a selenized metal precursor layer (CIGSS absorber layer). A high efficiency solar cell includes a CIGSS absorber layer formed by a process including selenizing a metal precursor using diethyl selenium to form the CIGSS absorber layer.

  14. National solar technology roadmap: Organic PV

    Energy Technology Data Exchange (ETDEWEB)

    Ginley, Dave [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2007-06-01

    This roadmap addresses all forms of solar cells that use organic molecules—including polymers, dendrimers, small molecules, and dyes—as absorbers or transporters, either in fully organic devices or in devices that also contain inorganic nanostructures.

  15. A nanophotonic solar thermophotovoltaic device.

    Science.gov (United States)

    Lenert, Andrej; Bierman, David M; Nam, Youngsuk; Chan, Walker R; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N

    2014-02-01

    The most common approaches to generating power from sunlight are either photovoltaic, in which sunlight directly excites electron-hole pairs in a semiconductor, or solar-thermal, in which sunlight drives a mechanical heat engine. Photovoltaic power generation is intermittent and typically only exploits a portion of the solar spectrum efficiently, whereas the intrinsic irreversibilities of small heat engines make the solar-thermal approach best suited for utility-scale power plants. There is, therefore, an increasing need for hybrid technologies for solar power generation. By converting sunlight into thermal emission tuned to energies directly above the photovoltaic bandgap using a hot absorber-emitter, solar thermophotovoltaics promise to leverage the benefits of both approaches: high efficiency, by harnessing the entire solar spectrum; scalability and compactness, because of their solid-state nature; and dispatchablility, owing to the ability to store energy using thermal or chemical means. However, efficient collection of sunlight in the absorber and spectral control in the emitter are particularly challenging at high operating temperatures. This drawback has limited previous experimental demonstrations of this approach to conversion efficiencies around or below 1% (refs 9, 10, 11). Here, we report on a full solar thermophotovoltaic device, which, thanks to the nanophotonic properties of the absorber-emitter surface, reaches experimental efficiencies of 3.2%. The device integrates a multiwalled carbon nanotube absorber and a one-dimensional Si/SiO2 photonic-crystal emitter on the same substrate, with the absorber-emitter areas optimized to tune the energy balance of the device. Our device is planar and compact and could become a viable option for high-performance solar thermophotovoltaic energy conversion.

  16. Radiation sterilization of absorbent cotton and of absorbent gauze

    International Nuclear Information System (INIS)

    Hosobuchi, Kazunari; Oka, Mitsuru; Kaneko, Akira; Ishiwata, Hiroshi.

    1986-01-01

    The bioburden of absorbent cotton and of absorbent gauze and their physical and chemical characteristics after irradiation are investigated. The survey conducted on contaminants of 1890 cotton samples from 53 lots and 805 gauze samples from 56 lots showed maximum numbers of microbes per g of the cotton and gauze were 859 (an average of 21.4) and 777 (an average of 42.2), respectively. Isolation and microbiological and biochemical tests of representative microbes indicated that all of them, except one, were bacilli. The sterilization dose at 10 -6 of sterlity assurance level was found to be 2.0 Mrad when irradiated the spores loaded on paper strips and examined populations having graded D values from 0.10 to 0.28 Mrad. The sterilization dose would be about 1.5 Mrad if subjected the average numbers of contaminants observed in this study to irradiation. No significant differences were found between the irradiated samples and control up to 2 Mrad in tensile strength, change of color, absorbency, sedimentation rate, soluble substances, and pH of solutions used for immersion and other tests conventionally used. These results indicate that these products can be sterilized by irradiation. (author)

  17. Digital Alloy Absorber for Photodetectors

    Science.gov (United States)

    Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)

    2016-01-01

    In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.

  18. Insight into magnetorheological shock absorbers

    CERN Document Server

    Gołdasz, Janusz

    2015-01-01

    This book deals with magnetorheological fluid theory, modeling and applications of automotive magnetorheological dampers. On the theoretical side a review of MR fluid compositions and key factors affecting the characteristics of these fluids is followed by a description of existing applications in the area of vibration isolation and flow-mode shock absorbers in particular. As a majority of existing magnetorheological devices operates in a so-called flow mode a critical review is carried out in that regard. Specifically, the authors highlight common configurations of flow-mode magnetorheological shock absorbers, or so-called MR dampers that have been considered by the automotive industry for controlled chassis applications. The authors focus on single-tube dampers utilizing a piston assembly with one coil or multiple coils and at least one annular flow channel in the piston.

  19. Energy transfer in nanowire solar cells with photon-harvesting shells

    KAUST Repository

    Peters, C. H.; Guichard, A. R.; Hryciw, A. C.; Brongersma, M. L.; McGehee, M. D.

    2009-01-01

    The concept of a nanowire solar cell with photon-harvesting shells is presented. In this architecture, organic molecules which absorb strongly in the near infrared where silicon absorbs weakly are coupled to silicon nanowires (SiNWs). This enables

  20. Acoustic Properties of Absorbent Asphalts

    Science.gov (United States)

    Trematerra, Amelia; Lombardi, Ilaria

    2017-08-01

    Road traffic is one of the greater cause of noise pollution in urban centers; a prolonged exposure to this source of noise disturbs populations subjected to it. In this paper is reported a study on the absorbent coefficients of asphalt. The acoustic measurements are carried out with a impedance tube (tube of Kundt). The sample are measured in three conditions: with dry material (traditional), “wet” asphalt and “dirty” asphalt.

  1. Solar radiation on domed roofs

    Energy Technology Data Exchange (ETDEWEB)

    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)

  2. Nonimaging secondary concentrators for large rim angle parabolic troughs with tubular absorbers.

    Science.gov (United States)

    Ries, H; Spirkl, W

    1996-05-01

    For parabolic trough solar collectors with tubular absorbers, we design new tailored secondary concentrators. The design is applicable for any rim angle of a parabolic reflector. With the secondary, the concentration can be increased by a factor of more than 2 with a compact secondary reflector consisting of a single piece, even for the important case of a rim angle of 90 deg. The parabolic reflector can be used without changes; the reduced absorber is still tubular but smaller than the original absorber and slightly displaced toward the primary.

  3. A comprehensive review on solar cookers

    International Nuclear Information System (INIS)

    Cuce, Erdem; Cuce, Pinar Mert

    2013-01-01

    In this paper, a thorough review of the available literature on solar cookers is presented. The review is performed in a thematic way in order to allow an easier comparison, discussion and evaluation of the findings obtained by researchers, especially on parameters affecting the performance of solar cookers. The review covers a historic overview of solar cooking technology, detailed description of various types of solar cookers, geometry parameters affecting performance of solar cookers such as booster mirrors, glazing, absorber plate, cooking pots, heat storage materials and insulation. Moreover, thermodynamic assessment of solar cooking systems and qualitative evaluation of thermal output offered by solar cookers are analyzed in detail. Complex designs of solar cookers/ovens with and without heat storage material are illustrated and furthermore possible methods to be able to enhance the power outputs of solar cooking systems are presented. Feasibility analysis, environmental impacts and future potential of solar cookers are also considered in the study.

  4. Solar Indices - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  5. Solar Indices - Solar Ultraviolet

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  6. Solar Indices - Solar Corona

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  7. Solar Indices - Solar Irradiance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  8. Immersible solar heater for fluids

    Science.gov (United States)

    Kronberg, James W.

    1995-01-01

    An immersible solar heater comprising a light-absorbing panel attached to a frame for absorbing heat energy from the light and transferring the absorbed heat energy directly to the fluid in which the heater is immersed. The heater can be used to heat a swimming pool, for example, and is held in position and at a preselected angle by a system of floats, weights and tethers so that the panel can operate efficiently. A skid can be used in one embodiment to prevent lateral movement of the heater along the bottom of the pool. Alternative embodiments include different arrangements of the weights, floats and tethers and methods for making the heater.

  9. CZTS nanoparticle absorber layer for thin film solar cells

    DEFF Research Database (Denmark)

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

    a pure CZTS kesterite phase without secondary phases as they result in structural inhomogeneity, local fluctuation of open circuit voltage and high carrier recombination [3]. This leads to poor device performance and repeatability issues. Here, we present how the synthesis parameters affect the resulting...... CZTS nanoparticles. The product is characterized by XRD, EDS, and Raman spectroscopy in order to fully detect possible secondary phases and characterize the CZTS phase. By combining Rietveld refinement of the XRD data with X-ray total scattering with PDF analysis, the nanoscale atomic structure...

  10. Solar thermoelectric generator

    Science.gov (United States)

    Toberer, Eric S.; Baranowski, Lauryn L.; Warren, Emily L.

    2016-05-03

    Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. A novel detailed balance model for STEGs is provided and applied to both state-of-the-art and idealized materials. STEGs can produce electricity by using sunlight to heat one side of a thermoelectric generator. While concentrated sunlight can be used to achieve extremely high temperatures (and thus improved generator efficiency), the solar absorber also emits a significant amount of black body radiation. This emitted light is the dominant loss mechanism in these generators. In this invention, we propose a solution to this problem that eliminates virtually all of the emitted black body radiation. This enables solar thermoelectric generators to operate at higher efficiency and achieve said efficient with lower levels of optical concentration. The solution is suitable for both single and dual axis solar thermoelectric generators.

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

    Science.gov (United States)

    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.

  12. An ultra-broadband multilayered graphene absorber

    KAUST Repository

    Amin, Muhammad; Farhat, Mohamed; Bagci, Hakan

    2013-01-01

    An ultra-broadband multilayered graphene absorber operating at terahertz (THz) frequencies is proposed. The absorber design makes use of three mechanisms: (i) The graphene layers are asymmetrically patterned to support higher order surface plasmon

  13. Formulation of heat absorbing glasses

    Directory of Open Access Journals (Sweden)

    Álvarez-Casariego, Pedro

    1996-06-01

    Full Text Available In the thermal exchanges between buildings and environment, glazing is an element of major importance, for it largely influences the so-called Solar Heat Gain and Thermal Losses. These parameters can be modified by applying different type of coatings onto glass surface or by adding colorant compounds during glass melting. The latter is a cheaper way to control the Solar Heat Gain. The knowledge of the laws governing the interaction between colorant compounds and solar radiation, allows us to define glass formulations achieving specific aesthetic requirements and solar energy absorption. In this paper two examples of application of the modelling of glass colorants spectral absorptance are presented. First is addressed to obtaining a glass with high luminous transmittance and low solar energy transmittance, and the other one to obtaining a glass with neutral colour appearance and minimized solar energy transmittance. Calculation formulas are defined together with photometric properties so-obtained. These type of glasses are particularly suitable to be used as building and automotive glazing, for they retain the mechanical characteristics and possibilities of transformation of standard glass.

    En los intercambios de energía entre un edificio y el medio exterior, el vidrio es el elemento de mayor importancia, por su influencia en la Ganancia de Calor Solar y en las Pérdidas Térmicas. Estos parámetros pueden ser modificados mediante el depósito de capas sobre el vidrio o mediante la adición de compuestos absorbentes de la radiación solar. Esta última vía es la más económica para controlar la Ganancia de Calor Solar. El conocimiento de las leyes que gobiernan la interacción de los diversos colorantes con la radiación solar, permite definir formulaciones de vidrios con características especificas de tipo estético y de absorción energética. En este trabajo se presentan dos ejemplos de aplicación de esta modelización de las

  14. Nonimaging concentrators for solar thermal energy

    Science.gov (United States)

    Winston, R.; Gallagher, J. J.

    1980-03-01

    A small experimental solar collector test facility was used to explore applications of nonimaging optics for solar thermal concentration in three substantially different configurations: a single stage system with moderate concentration on an evacuated absorber (a 5.25X evacuated tube Compound Parabolic Concentrator or CPC), a two stage system with high concentration and a non-evacuated absorber (a 16X Fresnel lens/CPC type mirror) and moderate concentration single stage systems with non-evacuated absorbers for lower temperature (a 3X and a 6.5X CPC). Prototypes of each of these systems were designed, built and tested. The performance characteristics are presented.

  15. Piezooptic effect of absorbing environment

    Directory of Open Access Journals (Sweden)

    Ю. А. Рудяк

    2013-07-01

    Full Text Available Application of piezooptic effect of absorbing environment for the definition of the parameter of stress deformation state was examined. The analysis of dielectric permeability tensor of imaginary parts was done. It is shown that changes in the real part dielectric permeability tensor mainly the indicator of fracture was fixed by means of mechanics interference methods and the changes in the imaginary part (α – real rate of absorption can be measured by means of analysis of light absorption and thus stress deformation state can be determined

  16. Energy absorbers as pipe supports

    International Nuclear Information System (INIS)

    Khlafallah, M.Z.; Lee, H.M.

    1985-01-01

    With the exception of springs, pipe supports currently in use are designed with the intent of maintaining their rigidity under load. Energy dissipation mechanisms in these pipe supports result in system damping on the order presented by Code Case N-411 of ASME Section III code. Examples of these energy dissipation mechanisms are fluids and gaps in snubbers, gaps in frame supports, and friction in springs and frame supports. If energy absorbing supports designed in accordance with Code Case N-420 are used, higher additional damping will result

  17. A solar absorption refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Kurbanov, N.; Daykhanov, S.; Khandurdyev, A.

    1982-01-01

    An assembly is described which is designed primarily for air conditioning. This device contains a transformer heated by solar energy, a heat exchanger generator with strong and weak solution lines connected to the irrigator and absorber vessel, respectively, and an evaporator. In order to reduce the metal consumption, the absorber and the evaporator are built in the form of a single indirectly air-cooled device with vertical dry and wet channels for primary and auxillary air respectively. The absorber irrigator is manufactured in a multisectional configuration with its sections located in the upper half of the front section of each dry channel, with the lower sections of these areas manufactured as a weak solution vessel separated from the remaining sections containing the dry channels by barriers.

  18. Tungsten based anisotropic metamaterial as an ultra-broadband absorber

    DEFF Research Database (Denmark)

    Lin, Yinyue; Cui, Yanxia; Ding, Fei

    2017-01-01

    : We show theoretically that an array of tungsten/germanium anisotropic nano-cones placed on top of a reflective substrate can absorb light at the wavelength range from 0.3 μm to 9 μm with an average absorption efficiency approaching 98%. It is found that the excitation of multiple orders of slow...... of the nano-cones and the interaction between neighboring nano-cones is quite weak. Our proposal has some potential applications in the areas of solar energy harvesting and thermal emitters....

  19. High temperature solar selective coatings

    Science.gov (United States)

    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.

  20. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping

    2016-05-18

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  1. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping; Wu, Ying; Lai, Yun

    2016-01-01

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  2. A solar air collector with integrated latent heat thermal storage

    Directory of Open Access Journals (Sweden)

    Klimes Lubomir

    2012-04-01

    Full Text Available Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data.

  3. Solar thermal power: the seamless solar link to the conventional power world

    International Nuclear Information System (INIS)

    Geyer, Michael; Quaschning, Volker

    2000-01-01

    This article focuses on solar thermal power generation and describes two solar thermal power concepts, namely, the parabolic trough or solar farm, and the solar central receiver or power tower. Details are given of grid-connected parabolic trough power plants in California and recent developments in collector design and absorber tubes, and the operation of power tower plants with different heat transfer media. Market issues are discussed, and solar thermal power projects under development, and application for support for solar thermal power projects under the Global Environment Facility's Operational Programme by Egypt, India, Iran, Mexico and Morocco are reported

  4. Increasing the efficiency of silicon heterojunction solar cells and modules by light soaking

    KAUST Repository

    Kobayashi, Eiji; De Wolf, Stefaan; Levrat, Jacques; Descoeudres, Antoine; Despeisse, Matthieu; Haug, Franz-Josef; Ballif, Christophe

    2017-01-01

    Silicon heterojunction solar cells use crystalline silicon (c-Si) wafers as optical absorbers and employ bilayers of doped/intrinsic hydrogenated amorphous silicon (a-Si:H) to form passivating contacts. Recently, we demonstrated that such solar

  5. A panchromatic anthracene-fused porphyrin sensitizer for dye-sensitized solar cells

    KAUST Repository

    Ball, James M.; Davis, Nicola K. S.; Wilkinson, James D.; Kirkpatrick, James; Teuscher, Joë l; Gunning, Robert; Anderson, Harry L.; Snaith, Henry J.

    2012-01-01

    The development of ruthenium-free sensitizers which absorb light over a broad range of the solar spectrum is important for improving the power conversion efficiency of dye-sensitized solar cells. Here we study three chemically tailored porphyrin

  6. Increased light harvesting in dye-sensitized solar cells with energy relay dyes

    KAUST Repository

    Hardin, Brian E.; Hoke, Eric T.; Armstrong, Paul B.; Yum, Jun-Ho; Comte, Pascal; Torres, Tomá s; Fré chet, Jean M. J.; Nazeeruddin, Md Khaja; Grä tzel, Michael; McGehee, Michael D.

    2009-01-01

    Conventional dye-sensitized solar cells have excellent charge collection efficiencies, high open-circuit voltages and good fill factors. However, dye-sensitized solar cells do not completely absorb all of the photons from the visible and near

  7. Solar building

    OpenAIRE

    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...

  8. ZnS top layer for enhancement of the crystallinity of CZTS absorber during the annealing

    DEFF Research Database (Denmark)

    Cazzaniga, Andrea Carlo; Crovetto, Andrea; Ettlinger, Rebecca Bolt

    2015-01-01

    Pulsed Laser Deposition (PLD) of thin films of Cu2ZnSnS4 (CZTS) has not yet led to solar cells with high efficiency. The reason for the relative low efficiency is discussed and a way to overcome this issue is presented. The present thin film absorbers of CZTS suffer from loss of volatile Zn durin...

  9. Solar energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role solar energy may have in the energy future of the US. The topics discussed in the chapter include the solar resource, solar architecture including passive solar design and solar collectors, solar-thermal concentrating systems including parabolic troughs and dishes and central receivers, photovoltaic cells including photovoltaic systems for home use, and environmental, health and safety issues

  10. Oxalate: Effect on calcium absorbability

    International Nuclear Information System (INIS)

    Heaney, R.P.; Weaver, C.M.

    1989-01-01

    Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species

  11. Thin Film Photovoltaic/Thermal Solar Panels

    Institute of Scientific and Technical Information of China (English)

    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.

  12. Modification of UV absorption profile of polymer film reflectors to increase solar-weighted reflectance

    Science.gov (United States)

    Jorgensen, Gary; Gee, Randall C.; White, David

    2017-05-02

    Provided are reflective thin film constructions including a reduced number of layers, which provides for increased solar-weighted hemispherical reflectance and durability. Reflective films include those comprising an ultraviolet absorbing abrasion resistant coating over a metal layer. Also provided are ultraviolet absorbing abrasion resistant coatings and methods for optimizing the ultraviolet absorption of an abrasion resistant coating. Reflective films disclosed herein are useful for solar reflecting, solar collecting, and solar concentrating applications, such as for the generation of electrical power.

  13. Optimal nonimaging integrated evacuated solar collector

    Science.gov (United States)

    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.

  14. An omnidirectional electromagnetic absorber made of metamaterials

    International Nuclear Information System (INIS)

    Cheng Qiang; Cui Tiejun; Jiang Weixiang; Cai Bengeng

    2010-01-01

    In a recent theoretical work by Narimanov and Kildishev (2009 Appl. Phys. Lett. 95 041106) an optical omnidirectional light absorber based on metamaterials was proposed, in which theoretical analysis and numerical simulations showed that all optical waves hitting the absorber are trapped and absorbed. Here we report the first experimental demonstration of an omnidirectional electromagnetic absorber in the microwave frequency. The proposed device is composed of non-resonant and resonant metamaterial structures, which can trap and absorb electromagnetic waves coming from all directions spirally inwards without any reflections due to the local control of electromagnetic fields. It is shown that the absorption rate can reach 99 per cent in the microwave frequency. The all-directional full absorption property makes the device behave like an 'electromagnetic black body', and the wave trapping and absorbing properties simulate, to some extent, an 'electromagnetic black hole.' We expect that such a device could be used as a thermal emitting source and to harvest electromagnetic waves.

  15. Movable air solar collector and its efficiency

    International Nuclear Information System (INIS)

    Lauva, A.; Aboltinš, A.; Palabinskis, J.; Karpova Sadigova, N.

    2008-01-01

    Implementing the guidelines of the Latvian National Programme for Energy in the field of alternative energy, intensive research shall be carried on regarding the use of solar energy, as it can be successfully used not only for the purposes of water heating and production of electrical energy, but also for air warming. The amount of heat necessary for the drying of rough forage and grain drying by active aeration in June, July and August can be obtained using solar radiation. The Latvian Guidelines for the Energy Development 2006-2016 state that the solar radiance in Latvia is of quite low intensity. The total amount of solar energy is 1109 kWh m -2 per year. The period of usage of the solar thermal energy is beginning from the last decade of April, when the intensity of radiation is 120 kWh m -2 , until the first decade of September. Within this period (approximately 1800 hours), it is possible to use the solar thermal energy by placing solar collectors. The usage of solar collectors for in drying of agricultural production is topical from the viewpoint of decreasing the consumption of energy used for the drying, as electrical energy and fossil energy resources become more expensive and tend to run out. In the processes that concern drying of agricultural production, efficiently enough solar radiation energy can be used. Due to this reason researching continues and expands in the field of usage of solar energy for the processes of drying and heating. The efficiency factor of the existing solar collectors is not high, but they are of simple design and cheep for production and exploitation. By improving the design of the solar collectors and choosing modern materials that absorb the solar radiation energy, it is possible the decrease the efficiency factor of solar collectors and decrease the production costs. In the scientific laboratory of grain drying and storage of Latvia University of Agriculture, a pilot device movable folding solar collector pilot device

  16. Comments on liquid hydrogen absorbers for MICE

    International Nuclear Information System (INIS)

    Green, Michael A.

    2003-01-01

    This report describes the heat transfer problems associated with a liquid hydrogen absorber for the MICE experiment. This report describes a technique for modeling heat transfer from the outside world, to the absorber case and in its vacuum vessel, to the hydrogen and then into helium gas at 14 K. Also presented are the equation for free convection cooling of the liquid hydrogen in the absorber

  17. Absorbed dose by a CMOS in radiotherapy

    International Nuclear Information System (INIS)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L. C.

    2011-10-01

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  18. Multiband Negative Permittivity Metamaterials and Absorbers

    Directory of Open Access Journals (Sweden)

    Yiran Tian

    2013-01-01

    Full Text Available Design and characteristics of multiband negative permittivity metamaterial and its absorber configuration are presented in this paper. The proposed multiband metamaterial is composed of a novel multibranch resonator which can possess four electric resonance frequencies. It is shown that, by controlling the length of the main branches of such resonator, the resonant frequencies and corresponding absorbing bands of metamaterial absorber can be shifted in a large frequency band.

  19. Preparation of super absorbent by irradiation polymerization

    International Nuclear Information System (INIS)

    Hua Fengjun; Tan Chunhong; Qian Mengping

    1995-01-01

    A kind of absorbent is prepared by gamma-rays irradiated by reversed-phase suspension polymerization. Drying particles have 1400 (g/g) absorbency in de-ionic water. Effects of reactive conditions, e.g.: dose-rate, dose, monomer concentration, degree of monomer neutralization and crosslinking agents on absorbency in de-ionic water are discussed. The cause of absorbing de-ionic water by polymer is related to its network structure and ionic equilibrium in particle. Accordingly, a suit reactive condition is chosen for preparation of hydro gel spheres

  20. Absorber rod drive for nuclear reactors

    International Nuclear Information System (INIS)

    Acher, H.

    1985-01-01

    The invention concerns a further addition to the invention of DE 33 42 830 A1. The free contact of the hollow piston with the nut due to hydraulic pressure is replaced by a hydraulic or spring attachment. The pressure system required to produce the hydraulic pressure is therefore omitted, and the electrical power required for driving the pump or the mass flow is also omitted. The absorber rod slotted along its longitudinal axis is replaced by an absorber rod, in the longitudinal axis of which a hollow piston is connected together with the absorber rod. This makes the absorber rod more stable, and assembly is simplified. (orig./HP) [de

  1. TPX/TFTR Neutral Beam energy absorbers

    International Nuclear Information System (INIS)

    Dahlgren, F.; Wright, K.; Kamperschroer, J.; Grisham, L.; Lontai, L.; Peters, C.; VonHalle, A.

    1993-01-01

    The present beam energy absorbing surfaces on the TFTR Neutral Beams such as Ion Dumps, Calorimeters, beam defining apertures, and scrapers, are simple water cooled copper plates which wee designed to absorb (via their thermal inertia) the incident beam power for two seconds with a five minute coal down interval between pulses. These components are not capable of absorbing the anticipated beam power loading for 1000 second TPX pulses and will have to be replaced with an actively cooled design. While several actively cooled energy absorbing designs were considered,, the hypervapotron elements currently being used on the JET beamlines were chosen due to their lower cooling water demands and reliable performance on JET

  2. Solar thermophotovoltaic system using nanostructures.

    Science.gov (United States)

    Ungaro, Craig; Gray, Stephen K; Gupta, Mool C

    2015-09-21

    This paper presents results on a highly efficient experimental solar thermophotovoltaic (STPV) system using simulated solar energy. An overall power conversion efficiency of 6.2% was recorded under solar simulation. This was matched with a thermodynamic model, and the losses within the system, as well as a path forward to mitigate these losses, have been investigated. The system consists of a planar, tungsten absorbing/emitting structure with an anti-reflection layer coated laser-microtextured absorbing surface and single-layer dielectric coated emitting surface. A GaSb PV cell was used to capture the emitted radiation and convert it into electrical energy. This simple structure is both easy to fabricate and temperature stable, and contains no moving parts or heat exchange fluids.

  3. Gaseous carbon dioxide absorbing column

    International Nuclear Information System (INIS)

    Harashina, Heihachi.

    1994-01-01

    The absorbing column of the present invention comprises a cyclone to which CO 2 gas and Ca(OH) 2 are blown to form CaCO 3 , a water supply means connected to an upper portion of the cyclone for forming a thin water membrane on the inner wall thereof, and a water processing means connected to a lower portion of the cyclone for draining water incorporating CaCO 3 . If a mixed fluid of CO 2 gas and Ca(OH) 2 is blown in a state where a flowing water membrane is formed on the inner wall of the cyclone, formation of CaCO 3 is promoted also in the inside of the cyclone in addition to the formation of CaCO 3 in the course of blowing. Then, formed CaCO 3 is discharged from the lower portion of the cyclone together with downwardly flowing water. With such procedures, solid contents such as CaCO 3 separated at the inner circumferential wall are sent into the thin water membrane, adsorbed and captured, and the solid contents are successively washed out, so that a phenomenon that the solid contents deposit and grow on the inner wall of the cyclone can be prevented effectively. (T.M.)

  4. Radiation absorbed doses in cephalography

    International Nuclear Information System (INIS)

    Eliasson, S.; Julin, P.; Richter, S.; Stenstroem, B.

    1984-01-01

    Radiation absorbed doses to different organs in the head and neck region in lateral (LAT) and postero-anterior (PA) cephalography were investigated. The doses were measured by thermoluminescence dosimeters (TLD) on a tissue equivalent phantom head. Lanthanide screens in speed group 4 were used at 90 and 85 k Vp. A near-focus aluminium dodger was used and the radiation beam was collimated strictly to the face. The maximum entrance dose from LAT was 0.25 mGy and 0.42 mGy from a PA exposure. The doses to the salivary glands ranged between 0.2 and 0.02 mGy at LAT and between 0.15 and 0.04 mGy at PA exposures. The average thyroid gland dose without any shielding was 0.11 mGy (LAT) and 0.06 mGy (PA). When a dodger was used the dose was reduced to 0.07 mGy (LAT). If the thyroid gland was sheilded off, the dose was further reduced to 0.01 mGy and if the thyroid region was collimated out of the primary radiation field the dose was reduced to only 0.005 mGy. (authors)

  5. Optimum design of composite panel with photovoltaic-thermo module. Absorbing effect of cooling panel; Hikari netsu fukugo panel no saiteki sekkei. Reikyaku panel no kyunetsu koka

    Energy Technology Data Exchange (ETDEWEB)

    Sato, M; Kikuchi, S; Tani, T [Science University of Tokyo, Tokyo (Japan); Kadotani, K; Imaizumi, H [Komatsu Ltd., Tokyo (Japan)

    1996-10-27

    The composite panel with photovoltaic-thermo module becomes higher in energy-saving than the conventional air-conditioning system by the independent radiational heating and cooling effect obtained when the generating panel using a solar cell module is combined with the heating and cooling panel using a thermo-element module. The output of a solar cell module can be directly used because the solar cell module operates in AC. This paper reports the relation between the absorbed value and power consumption of the cooling panel, while paying attention to the cooling panel. The performance coefficient of the maximum absorbed value from an non-absorbing substance to a cooling panel is 2 to 3. Assume that the cooling panel during non-adiabatic operation is operated using a solar cell module of 800 W/m{sup 2} in solar intensity and 15% in conversion efficiency. The cooling-surface temperature difference is 12.12 K, and the maximum absorbed value of a non-absorbing substance to a cooling panel is 39.12 W/m{sup 2}. The absorbed value of the outer temperature to the cooling panel is 74.4 W/m{sup 2}, and each performance coefficient is 3.26 and 0.62. The absorbed value must be calculated for evaluation from the cooling-surface temperature difference measured directly from the cooling panel. 4 refs., 8 figs., 1 tab.

  6. Photon management in solar cells

    CERN Document Server

    Rau, Uwe; Gombert, Andreas

    2015-01-01

    Written by renowned experts in the field of photon management in solar cells, this one-stop reference gives an introduction to the physics of light management in solar cells, and discusses the different concepts and methods of applying photon management. The authors cover the physics, principles, concepts, technologies, and methods used, explaining how to increase the efficiency of solar cells by splitting or modifying the solar spectrum before they absorb the sunlight. In so doing, they present novel concepts and materials allowing for the cheaper, more flexible manufacture of solar cells and systems. For educational purposes, the authors have split the reasons for photon management into spatial and spectral light management. Bridging the gap between the photonics and the photovoltaics communities, this is an invaluable reference for materials scientists, physicists in industry, experimental physicists, lecturers in physics, Ph.D. students in physics and material sciences, engineers in power technology, appl...

  7. Cermet coatings for solar Stirling space power

    International Nuclear Information System (INIS)

    Jaworske, Donald A.; Raack, Taylor

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic, are being considered for the heat inlet surface of a solar Stirling space power convertor. The role of the cermet coating is to absorb as much of the incident solar energy as possible. The ability to mix metal and ceramic at the atomic level offers the opportunity to tailor the composition and the solar absorptance of these coatings. Several candidate cermet coatings were created and their solar absorptance was characterized as-manufactured and after exposure to elevated temperatures. Coating composition was purposely varied through the thickness of the coating. As a consequence of changing composition, islands of metal are thought to form in the ceramic matrix. Computer modeling indicated that diffusion of the metal atoms played an important role in island formation while the ceramic was important in locking the islands in place. Much of the solar spectrum is absorbed as it passes through this labyrinth

  8. Absorbing Property of Multi-layered Short Carbon Fiber Absorbing Coating

    OpenAIRE

    Liu, Zhaohui; Tao, Rui; Ban, Guodong; Luo, Ping

    2018-01-01

    The radar absorbing coating was prepared with short carbon fiber asabsorbent and waterborne polyurethane (WPU) as matrix resin. The coating’s absorbing property was tested with vectornetwork analyzer, using aramid honeycomb as air layer which was matched withcarbon fiber coating. The results demonstrate that the single-layered carbonfiber absorbing coating presented relatively poor absorbing property when thelayer was thin, and the performance was slightly improved after the matched airlayer ...

  9. Absorber element for fast breeder reactor

    International Nuclear Information System (INIS)

    Verset, L.

    1987-01-01

    This absorber element is characterized by a new head which avoids an accident disconnection of the mobil absorber. This head is made by a superior piece which can take shore up an adjusting ring on an adjusting bearing on the inferior piece. The intermediate piece is catched at the superior piece by a link of chain [fr

  10. Analysis of absorbing times of quantum walks

    International Nuclear Information System (INIS)

    Yamasaki, Tomohiro; Kobayashi, Hirotada; Imai, Hiroshi

    2003-01-01

    Quantum walks are expected to provide useful algorithmic tools for quantum computation. This paper introduces absorbing probability and time of quantum walks and gives both numerical simulation results and theoretical analyses on Hadamard walks on the line and symmetric walks on the hypercube from the viewpoint of absorbing probability and time

  11. Absorber transmissivities in 57Fe Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Ballet, O.

    1985-01-01

    Some useful relations are derived for the polarization dependent optical index of 57 Fe Moessbauer absorbers. Real rotation matrices are extensively used and, besides wave-direction dependence, their properties simplify also the treatment of texture and f-anisotropy. The derivation of absorber transmissivities from the optical index is discussed with a special emphasis on line overlapping. (Auth.)

  12. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    Science.gov (United States)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; hide

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  13. Development of 12.5 m² Solar Collector Panel for Solar Heating Plants

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian; Furbo, Simon; Shah, Louise Jivan

    2004-01-01

    and large solar heating systems. Based on the theoretical findings a prototype of an improved HT solar collector was built and tested side-by-side with the original HT solar collector. The improved HT collector makes use of a changed insulation material, an absorber with improved absorptance and emittance......Theoretical and experimental investigations have elucidated how different changes in the design of the 12.5 m(2) HT flat-plate solar collector from the Danish company ARCON Solvarme A/S influence the solar collector efficiency and the yearly thermal performance. The collector is designed for medium...

  14. Solar warming systems of water installed in Colombia. Photovoltaic solar systems installed in the Country

    International Nuclear Information System (INIS)

    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

  15. Liquid absorber experiments in ZED-2

    International Nuclear Information System (INIS)

    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)

  16. Solar Features - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A solar flare is a short-lived sudden increase in the intensity of radiation emitted in the neighborhood of sunspots. For many years it was best monitored in the...

  17. Numerical evaluation of an innovative cup layout for open volumetric solar air receivers

    Science.gov (United States)

    Cagnoli, Mattia; Savoldi, Laura; Zanino, Roberto; Zaversky, Fritz

    2016-05-01

    This paper proposes an innovative volumetric solar absorber design to be used in high-temperature air receivers of solar power tower plants. The innovative absorber, a so-called CPC-stacked-plate configuration, applies the well-known principle of a compound parabolic concentrator (CPC) for the first time in a volumetric solar receiver, heating air to high temperatures. The proposed absorber configuration is analyzed numerically, applying first the open-source ray-tracing software Tonatiuh in order to obtain the solar flux distribution on the absorber's surfaces. Next, a Computational Fluid Dynamic (CFD) analysis of a representative single channel of the innovative receiver is performed, using the commercial CFD software ANSYS Fluent. The solution of the conjugate heat transfer problem shows that the behavior of the new absorber concept is promising, however further optimization of the geometry will be necessary in order to exceed the performance of the classical absorber designs.

  18. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

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

    African Journals Online (AJOL)

    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 ...

  20. Climate variation based on temperature and solar radiation data ...

    African Journals Online (AJOL)

    ckaonga

    2015-03-12

    Mar 12, 2015 ... addition, the concentration of carbon dioxide over Malawi within the same period as temperature and solar radiation data ... plant diseases and pests which may have adverse effects ... object that absorbs and emits radiation).

  1. Design of a nonlinear torsional vibration absorber

    Science.gov (United States)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  2. BM Solar Cells

    KAUST Repository

    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.

  3. BM Solar Cells

    KAUST Repository

    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.

  4. Method of absorbing UF6 from gaseous mixtures in alkamine absorbents

    International Nuclear Information System (INIS)

    Lafferty, R.H.; Smiley, S.H.; Radimer, K.J.

    1976-01-01

    A method is described for recovering UF 6 from gaseous mixtures by absorption in a liquid. The liquid absorbent must have a relatively low viscosity and at least one component of the absorbent is an alkamine having less than 3 carbon atoms bonded to the amino nitrogen, less than 2 of the carbon atoms other than those bonded to the amino nitrogen are free of the hydroxy radical and precipitate the absorbed uranium from the absorbent. At least one component of the absorbent is chosen from the group consisting of ethanolamine, diethanolamine, and 3-methyl-3-amino-propane-diol-1,2

  5. Solar heating system

    Science.gov (United States)

    Schreyer, James M.; Dorsey, George F.

    1982-01-01

    An improved solar heating system in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75.degree. to 180.degree. F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing and releasing heat for distribution.

  6. Improved solar heating systems

    Science.gov (United States)

    Schreyer, J.M.; Dorsey, G.F.

    1980-05-16

    An improved solar heating system is described in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75 to 180/sup 0/F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing ad releasing heat for distribution.

  7. On the definition of absorbed dose

    International Nuclear Information System (INIS)

    Grusell, Erik

    2015-01-01

    Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before. - Highlights: • A stringent definition of absorbed dose is given. • This requires the definition of an irradiation and a suitable probability space. • A stringent definition is important for an understanding of the concept absorbed dose

  8. Radioactive iodine absorbing properties of tetrathiafulvalene

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Tomiyasu; Nakamura, Asao (Ajinomoto Co. Inc., Kawasaki, Kanagawa (Japan). Central Research Labs.); Nogawa, Norio; Oohashi, Kunio; Morikawa, Naotake

    1989-05-01

    For the purpose of searching some effective absorbents of gaseous radioactive iodine, 16 substances considered as having an affinity for iodine were investigated with regular iodine and /sup 125/I. In a preliminary survey, only tetrathiafulvalene (TTF) was found to have satisfactory absorbing properties comparable to activated charcoal. A further detailed comparison of the properties between TTF and activated charcoal led us to the conclusion that the former has more preferable properties as absorbent of radioactive iodine than the latter in all points studied. The results are summarized as follows: (1) The absorption of iodine on TTF in atmosphere was about twice as much as that on activated charcoal. Desorption of iodine from saturatedly absorbed iodine on TTF was practically negligible except trace amount of initial desorption, while that on activated charcoal was considerable (3%/50h) even in the air at room temperature. (2) Absorbed amount of iodine on activated charcoal decreased with increasing gaseous iodine concentration, air flow rate, on humidity of flowing-air. On the other hand, those factors scarcely affected that on TTF. Under an air flow rate of 1m/s, activated charcoal absorbs only 80% of iodine, while TTF absorbs more than 99%. (3) In flowing-air saturated with water vapor, iodine absorbed on activated charcoal was gradually liberated although by small amount (0.08%/100h), while that on TTF was much more stable for a long period (0.004%/100h). As a conclusion, TTF is considered to be useful as a quite effective radioactive iodine absorbent, especially in the case where protection from radioactive iodine should be serious, though it is expensive now. (author).

  9. Estimation of Absorbed Dose in Occlusal Radiography

    International Nuclear Information System (INIS)

    Yoo, Young Ah; Choi, Karp Shick; Lee, Sang Han

    1990-01-01

    The purpose of this study was to estimate absorbed dose of each important anatomic site of phantom (RT-210 Head and Neck Section R, Humanoid Systems Co., U.S.A.) head in occlusal radiography. X-radiation dosimetry at 12 anatomic sites in maxillary anterior topography, maxillary posterior topography, mandibular anterior cross-section, mandibular posterior cross-section, mandibular anterior topographic, mandibular posterior topographic occlusal projection was performed with calcium sulfate thermoluminescent dosimeters under 70 Kvp and 15 mA, 1/4 second (8 inch cone ) and 1 second (16 inch cone) exposure time. The results obtained were as follows: Skin surface produced highest absorbed dose ranged between 3264 mrad and 4073 mrad but there was little difference between projections. In maxillary anterior topographic occlusal radiography, eyeballs, maxillary sinuses, and pituitary gland sites produced higher absorbed doses than those of other sites. In maxillary posterior topographic occlusal radiography, exposed eyeball site and exposed maxillary sinus site produced high absorbed doses. In mandibular anterior cross-sectional occlusal radiography, all sites were produced relatively low absorbed dose except eyeball sites. In Mandibular posterior cross-sectional occlusal radiography, exposed eyeball site and exposed maxillary sinus site were produced relatively higher absorbed doses than other sites. In mandibular anterior topographic occlusal radiography, maxillary sinuses, submandibular glands, and thyroid gland sites produced high absorbed doses than other sites. In mandibular posterior topographic occlusal radiography, submandibular gland site of the exposed side produced high absorbed dose than other sites and eyeball site of the opposite side produced relatively high absorbed dose.

  10. Radioactive iodine absorbing properties of tetrathiafulvalene

    International Nuclear Information System (INIS)

    Ito, Tomiyasu; Nakamura, Asao; Nogawa, Norio; Oohashi, Kunio; Morikawa, Naotake.

    1989-01-01

    For the purpose of searching some effective absorbents of gaseous radioactive iodine, 16 substances considered as having an affinity for iodine were investigated with regular iodine and 125 I. In a preliminary survey, only tetrathiafulvalene (TTF) was found to have satisfactory absorbing properties comparable to activated charcoal. A further detailed comparison of the properties between TTF and activated charcoal led us to the conclusion that the former has more preferable properties as absorbent of radioactive iodine than the latter in all points studied. The results are summarized as follows: (1) The absorption of iodine on TTF in atmosphere was about twice as much as that on activated charcoal. Desorption of iodine from saturatedly absorbed iodine on TTF was practically negligible except trace amount of initial desorption, while that on activated charcoal was considerable (3%/50h) even in the air at room temperature. (2) Absorbed amount of iodine on activated charcoal decreased with increasing gaseous iodine concentration, air flow rate, on humidity of flowing-air. On the other hand, those factors scarcely affected that on TTF. Under an air flow rate of 1m/s, activated charcoal absorbs only 80% of iodine, while TTF absorbs more than 99%. (3) In flowing-air saturated with water vapor, iodine absorbed on activated charcoal was gradually liberated although by small amount (0.08%/100h), while that on TTF was much more stable for a long period (0.004%/100h). As a conclusion, TTF is considered to be useful as a quite effective radioactive iodine absorbent, especially in the case where protection from radioactive iodine should be serious, though it is expensive now. (author)

  11. Material Technologies Developments for Solar Hydrogen

    International Nuclear Information System (INIS)

    Agrafiotis, C.; Pagkoura, C.; Lorentzou, S.; Hoguet, J.C.; Konstandopoulos, A.G.

    2006-01-01

    The present work presents recent activities of our Laboratory in the field of solar-aided hydrogen production materials and reactor technologies that can be fully integrated into solar thermal power plants. Emphasis is given on structured monolithic solar reactors where ceramic supports optimized to absorb solar radiation and develop sufficiently high temperatures, are coated with active materials to perform a variety of 'solar-aided' reactions such as water splitting or natural gas reforming. Particular examples discussed include properties'' assessment of monolithic ceramic honeycombs used as volumetric solar thermal reactors/receivers, synthesis of active water-splitting redox materials for the production of hydrogen and their tailored deposition upon porous supports and design, operation simulation and performance optimization of structured monolithic solar hydrogen production reactors. (authors)

  12. Preheating Water In The Covers Of Solar Water Heaters

    Science.gov (United States)

    Bhandari, Pradeep

    1995-01-01

    Solar water heaters that include glass covers over absorber plates redesigned to increase efficiencies according to proposal. Redesign includes modification of single-layer glass cover into double-layer glass cover and addition of plumbing so cool water to be heated made to flow between layers of cover before entering absorber plate.

  13. Semiconductor saturable absorbers for ultrafast terahertz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    states, due to conduction band onparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation fluence, are extracted by fits to a classic saturable absorber model. Further, we observe THz pulse......We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum...

  14. Absorbed dose by a CMOS in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L. C., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-10-15

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  15. Energy Absorbing Effectiveness – Different Approaches

    Directory of Open Access Journals (Sweden)

    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.

  16. Graphene and Graphene Metamaterials for Terahertz Absorbers

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim

    2013-01-01

    Graphene, due to the possibility to tune its conductivity, is the promising material for a range of the terahertz (THz) applications, such as tunable reflectors, absorbers, modulators, filters and polarization converters. Subwavelength structuring of graphene in order to form metamaterials allows...... for even more control over the THz waves. In this poster presentation I will show an elegant way to describe the graphene metamaterials and the design of graphene based absorbers. I will also present our recent experimental results on the graphene absorbers characterization....

  17. Fabrication of Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) absorber films based on solid-phase synthesis and blade coating processes

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ruixin, E-mail: mrx_601@126.com [School of Metallurgy and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Special Melting and Preparation of High-end Metal Materials, Beijing 100083 (China); Yang, Fan; Li, Shina; Zhang, Xiaoyong; Li, Xiang; Cheng, Shiyao; Liu, Zilin [School of Metallurgy and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2016-04-15

    Graphical abstract: - Highlights: • Pure CZTS nano-crystalline have been prepared based on solid-phase synthesis. • A simple and modified doctor blade process followed by a selenization technique was utilized to fabricate CZTSSe absorber films. • Comparative studies on the properties of CZTS and CZTSSe absorber films have been investigated. • The band gap of CZTSSe absorber films was determined to be 1.26 eV. - Abstract: CZTSSe is an important earth abundant collection of materials for the development of low cost and high efficiency thin film solar cells. This work developed a simple non-vacuum-based route to fabricate CZTSSe absorber films. This was demonstrated by first synthesizing Cu{sub 2}ZnSnS{sub 4} (CZTS) nano-crystalline based on solid-phase synthesis. Then a stable colloidal ink composed of CZTS nano-crystalline was blade coated on Mo-coated substrates followed by an annealing process under Ar atmosphere. After CZTS films formation, the films were sintered into CZTSSe absorber films by exposing them under Selenium vapor. The formation of a kesterite type CZTS was confirmed using X-ray diffraction and Raman scattering measurements. The band gap of CZTSSe absorber films was determined to be 1.26 eV, which was appropriate for use as an absorber layer in thin film solar cells. The CZTSSe absorber films showed a good photovoltatic performance, demonstrating this simple approach had great potential for CZTSSe solar cell production.

  18. Relativistic solar sails

    Science.gov (United States)

    Güémez, J.; Fiolhais, M.

    2018-05-01

    We apply the four-vector formalism of special relativity to describe various interaction processes of photons with a solar sail, in two cases: when the sail’s surface is a perfect mirror, and when it is a body coated with a totally absorbing material. We stress the pedagogical value of implementing simultaneously both the linear momentum and the energy conservation in a covariant fashion, as our formalism inherently does. It also allows for a straightforward change of the description of a certain process in different inertial reference frames.

  19. Solar Energy.

    Science.gov (United States)

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  20. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary goal is to build and test a rigid Lithium Chloride Absorber Radiator (LCAR) coupon based on honeycomb geometry that would be applicable for EVA and...

  1. Full-flow absorbers. Every centimetre counts

    Energy Technology Data Exchange (ETDEWEB)

    Berner, Joachim

    2012-07-01

    New absorbers with a maximised area for heat exchange with the thermal medium are significantly more efficient than the presently typical designs. Both the industry and researchers are working to revive an old idea. (orig.)

  2. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

    1993-01-01

    This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

  3. An ultra-broadband multilayered graphene absorber

    KAUST Repository

    Amin, Muhammad

    2013-01-01

    An ultra-broadband multilayered graphene absorber operating at terahertz (THz) frequencies is proposed. The absorber design makes use of three mechanisms: (i) The graphene layers are asymmetrically patterned to support higher order surface plasmon modes that destructively interfere with the dipolar mode and generate electromagnetically induced absorption. (ii) The patterned graphene layers biased at different gate voltages backedup with dielectric substrates are stacked on top of each other. The resulting absorber is polarization dependent but has an ultra-broadband of operation. (iii) Graphene\\'s damping factor is increased by lowering its electron mobility to 1000cm 2=Vs. Indeed, numerical experiments demonstrate that with only three layers, bandwidth of 90% absorption can be extended upto 7THz, which is drastically larger than only few THz of bandwidth that can be achieved with existing metallic/graphene absorbers. © 2013 Optical Society of America.

  4. Thin film solar cells from earth abundant materials growth and characterization of Cu2(ZnSn)(SSe)4 thin films and their solar cells

    CERN Document Server

    Kodigala, Subba Ramaiah

    2013-01-01

    The fundamental concept of the book is to explain how to make thin film solar cells from the abundant solar energy materials by low cost. The proper and optimized growth conditions are very essential while sandwiching thin films to make solar cell otherwise secondary phases play a role to undermine the working function of solar cells. The book illustrates growth and characterization of Cu2ZnSn(S1-xSex)4 thin film absorbers and their solar cells. The fabrication process of absorber layers by either vacuum or non-vacuum process is readily elaborated in the book, which helps for further developm

  5. Solar energy

    Science.gov (United States)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  6. Solar Combisystems

    DEFF Research Database (Denmark)

    Thür, Alexander

    2006-01-01

    This note first introduces what is a solar combisystem, the structure how a solar combisystem is build up and what are criteria’s to evaluate a solar combisystem concept. Further on the main components of a solar combisystem, the main characteristics and possible advantages and disadvantages...... compared to each other are described. It is not the goal of this note to explain the technical details how to design all components of a solar combisystem. This is done during other lectures of the solar course and in other basic courses as well. This note tries to explain how a solar combisystem...

  7. Phase Space Exchange in Thick Wedge Absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2017-01-01

    The problem of phase space exchange in wedge absorbers with ionization cooling is discussed. The wedge absorber exchanges transverse and longitudinal phase space by introducing a position-dependent energy loss. In this paper we note that the wedges used with ionization cooling are relatively thick, so that single wedges cause relatively large changes in beam phase space. Calculation methods adapted to such “thick wedge” cases are presented, and beam phase-space transformations through such wedges are discussed.

  8. Semiconductor saturable absorbers for ultrafast THz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths.......We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths....

  9. Actual behaviour of a ball vibration absorber

    Czech Academy of Sciences Publication Activity Database

    Pirner, Miroš

    2002-01-01

    Roč. 90, č. 8 (2002), s. 987-1005 ISSN 0167-6105 R&D Projects: GA ČR(CZ) GV103/96/K034 Institutional support: RVO:68378297 Keywords : TV towers * wind-excited vibrations * vibration absorbers * pendulum absorber Subject RIV: JM - Building Engineering Impact factor: 0.513, year: 2002 http://www.sciencedirect.com/science/article/pii/S0167610502002155#

  10. A Wedge Absorber Experiment at MICE

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermilab; Mohayai, Tanaz [IIT, Chicago; Rogers, Chris [Rutherford; Snopok, Pavel [IIT, Chicago; Summers, Don [Mississippi U.

    2017-05-01

    Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

  11. Solar Systems

    Science.gov (United States)

    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.

  12. Adaptive Piezoelectric Absorber for Active Vibration Control

    Directory of Open Access Journals (Sweden)

    Sven Herold

    2016-02-01

    Full Text Available Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration absorbers and neutralizers. In order to respond to changes in system properties and/or the frequency of excitation forces, in this work, adaptive vibration compensation by a tunable piezoelectric vibration absorber is investigated. A special design containing piezoelectric stack actuators is used to cover a large tuning range for the natural frequency of the adaptive vibration absorber, while also the utilization as an active dynamic inertial mass actuator for active control concepts is possible, which can help to implement a broadband vibration control system. An analytical model is set up to derive general design rules for the system. An absorber prototype is set up and validated experimentally for both use cases of an adaptive vibration absorber and inertial mass actuator. Finally, the adaptive vibration control system is installed and tested with a basic truss structure in the laboratory, using both the possibility to adjust the properties of the absorber and active control.

  13. Solar radiophysics

    International Nuclear Information System (INIS)

    McLean, D.J.; Labrum, N.R.

    1985-01-01

    This book treats all aspects of solar radioastronomy at metre wavelengths, particularly work carried out on the Australian radioheliograph at Culgoora, with which most of the authors have been associated in one way or another. After an introductory section on historical aspects, the solar atmosphere, solar flares, and coronal radio emission, the book deals with instrumentation, theory, and details of observations and interpretations of the various aspects of metrewave solar radioastronomy, including burst types, solar storms, and the quiet sun. (U.K.)

  14. Absorber and regenerator models for liquid desiccant air conditioning systems. Validation and comparison using experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Krause, M.; Heinzen, R.; Jordan, U.; Vajen, K. [Kassel Univ., Inst. of Thermal Engineering, Kassel (Germany); Saman, W.; Halawa, E. [Sustainable Energy Centre, Univ. of South Australia, Mawson Lakes, Adelaide (Australia)

    2008-07-01

    Solar assisted air conditioning systems using liquid desiccants represent a promising option to decrease high summer energy demand caused by electrically driven vapor compression machines. The main components of liquid desiccant systems are absorbers for dehumidifying and cooling of supply air and regenerators for concentrating the desiccant. However, high efficient and validated reliable components are required and the design and operation have to be adjusted to each respective building design, location, and user demand. Simulation tools can help to optimize component and system design. The present paper presents new developed numerical models for absorbers and regenerators, as well as experimental data of a regenerator prototype. The models have been compared with a finite-difference method model as well as experimental data. The data are gained from the regenerator prototype presented and an absorber presented in the literature. (orig.)

  15. Development of a Polymer-carbon Nanotubes based Economic Solar Collector

    OpenAIRE

    Kim, S. I.; Kissick, John; Spence, Stephen; Boyle, Christine

    2014-01-01

    A low cost solar collector was developed by using polymeric components as opposed to metal and glass components of traditional solar collectors. In order to utilize polymers for the absorber of the solar collector, Carbon Nanotubes (CNT) has been added as a filler to improve the thermal conductivity and the solar absorptivity of polymers. The solar collector was designed as a multi-layer construction with considering the economic manufacturing. Through the mathematical heat transfer analysis,...

  16. Solar advanced internal film receiver

    International Nuclear Information System (INIS)

    Torre Cabezas, M. de la

    1990-01-01

    In a Solar Central Internal Film Receiver, the heat absorbing fluid (a molten nitrate salt) flows in a thin film down over the non illuminated side of an absorber panel. Since the molten salt working fluid is not contained in complicated tube manifolds, the receiver design is simples than a conventional tube type-receiver resulting in a lower cost and a more reliable receiver. The Internal Film Receiver can be considered as an alternative to the Direct Absorption Receiver, in the event that the current problems of the last one can not be solved. It also describes here the test facility which will be used for its solar test, and the test plans foreseen. (Author) 17 refs

  17. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    DEFF Research Database (Denmark)

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

    2005-01-01

    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 fins. 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...

  18. Method of absorbance correction in a spectroscopic heating value sensor

    Science.gov (United States)

    Saveliev, Alexei; Jangale, Vilas Vyankatrao; Zelepouga, Sergeui; Pratapas, John

    2013-09-17

    A method and apparatus for absorbance correction in a spectroscopic heating value sensor in which a reference light intensity measurement is made on a non-absorbing reference fluid, a light intensity measurement is made on a sample fluid, and a measured light absorbance of the sample fluid is determined. A corrective light intensity measurement at a non-absorbing wavelength of the sample fluid is made on the sample fluid from which an absorbance correction factor is determined. The absorbance correction factor is then applied to the measured light absorbance of the sample fluid to arrive at a true or accurate absorbance for the sample fluid.

  19. Electronic bandstructure of the ZnTe absorber material

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, Daniel [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Schmidt, Heidemarie [Forschungszentrum Dresden-Rossendorf, Dresden (Germany)

    2009-07-01

    Due to its large absorption coefficient, zinc telluride proved to be useful for the production of high-efficiency multi-junction solar cells. Nowadays ZnTe with a mixture of zincblende and wurtzite phases is fabricated by thin film growth techniques. The optical properties of both phases have been extensively studied by ab initio density functional methods. Here we focus on the question whether the effective electron and hole mass in ZnTe are small enough to meet the high-efficiency expectation of the ZnTe absorber material in solar cells and present direction dependent effective mass and Luttinger and Luttinger-like parameters of cubic and wurtzite ZnTe, respectively. Making use of the transferability of ionic model potential parameters and the experimentally known transition energies of different II-VI compounds ZnX (X=O,S,Se,Te), we obtained one single set of cationic model parameters for the Zn atom. The calculations have been performed by means of the empirical pseudopotential method using a simple empty core model potential.

  20. Fabrication and characterization of a slanting-type solar water ...

    African Journals Online (AJOL)

    The system includes four major components; a wooden basin of surface area 0.16 m2, an absorber surface, a slanting glass roof and a condensate channel. Very cheap locally available materials were used to fabricate the solar still. The solar still produced an average of 0.09 m3 of distilled water per day, and this study was ...

  1. Solar Energy Education. Renewable energy activities for chemistry and physics

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    Information on renewable energy sources is provided for students in this teachers' guide. With the chemistry and physics student in mind, solar energy topics such as absorber plate coatings for solar collectors and energy collection and storage methods are studied. (BCS)

  2. Thermally Resilient, Broadband Optical Absorber from UV to IR Derived from Carbon Nanostructures

    Science.gov (United States)

    Kaul, Anupama B.; Coles, James B.

    2012-01-01

    Optical absorber coatings have been developed from carbon-based paints, metal blacks, or glassy carbon. However, such materials are not truly black and have poor absorption characteristics at longer wavelengths. The blackness of such coatings is important to increase the accuracy of calibration targets used in radiometric imaging spectrometers since blackbody cavities are prohibitively large in size. Such coatings are also useful potentially for thermal detectors, where a broadband absorber is desired. Au-black has been a commonly used broadband optical absorber, but it is very fragile and can easily be damaged by heat and mechanical vibration. An optically efficient, thermally rugged absorber could also be beneficial for thermal solar cell applications for energy harnessing, particularly in the 350-2,500 nm spectral window. It has been demonstrated that arrays of vertically oriented carbon nanotubes (CNTs), specifically multi-walled-carbon- nanotubes (MWCNTs), are an exceptional optical absorber over a broad range of wavelengths well into the infrared (IR). The reflectance of such arrays is 100x lower compared to conventional black materials, such as Au black in the spectral window of 350-2,500 nm. Total hemispherical measurements revealed a reflectance of approximately equal to 1.7% at lambda approximately equal to 1 micrometer, and at longer wavelengths into the infrared (IR), the specular reflectance was approximately equal to 2.4% at lambda approximately equal to 7 micrometers. The previously synthesized CNTs for optical absorber applications were formed using water-assisted thermal chemical vapor deposition (CVD), which yields CNT lengths in excess of 100's of microns. Vertical alignment, deemed to be a critical feature in enabling the high optical absorption from CNT arrays, occurs primarily via the crowding effect with thermal CVD synthesized CNTs, which is generally not effective in aligning CNTs with lengths less than 10 m. Here it has been shown that the

  3. Warm Absorber Diagnostics of AGN Dynamics

    Science.gov (United States)

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  4. Increasing the efficiency of solar thermal panels

    Science.gov (United States)

    Dobrnjac, M.; Latinović, T.; Dobrnjac, S.; Živković, P.

    2016-08-01

    The popularity of solar heating systems is increasing for several reasons. These systems are reliable, adaptable and pollution-free, because the renewable solar energy is used. There are many variants of solar systems in the market mainly constructed with copper pipes and absorbers with different quality of absorption surface. Taking into account the advantages and disadvantages of existing solutions, in order to increase efficiency and improve the design of solar panel, the innovative solution has been done. This new solar panel presents connection of an attractive design and the use of constructive appropriate materials with special geometric shapes. Hydraulic and thermotechnical tests that have been performed on this panel showed high hydraulic and structural stability. Further development of the solar panel will be done in the future in order to improve some noticed disadvantages.

  5. Robust and Low-Cost Flame-Treated Wood for High-Performance Solar Steam Generation.

    Science.gov (United States)

    Xue, Guobin; Liu, Kang; Chen, Qian; Yang, Peihua; Li, Jia; Ding, Tianpeng; Duan, Jiangjiang; Qi, Bei; Zhou, Jun

    2017-05-03

    Solar-enabled steam generation has attracted increasing interest in recent years because of its potential applications in power generation, desalination, and wastewater treatment, among others. Recent studies have reported many strategies for promoting the efficiency of steam generation by employing absorbers based on carbon materials or plasmonic metal nanoparticles with well-defined pores. In this work, we report that natural wood can be utilized as an ideal solar absorber after a simple flame treatment. With ultrahigh solar absorbance (∼99%), low thermal conductivity (0.33 W m -1 K -1 ), and good hydrophilicity, the flame-treated wood can localize the solar heating at the evaporation surface and enable a solar-thermal efficiency of ∼72% under a solar intensity of 1 kW m -2 , and it thus represents a renewable, scalable, low-cost, and robust material for solar steam applications.

  6. Identifying the perfect absorption of metamaterial absorbers

    Science.gov (United States)

    Duan, G.; Schalch, J.; Zhao, X.; Zhang, J.; Averitt, R. D.; Zhang, X.

    2018-01-01

    We present a detailed analysis of the conditions that result in unity absorption in metamaterial absorbers to guide the design and optimization of this important class of functional electromagnetic composites. Multilayer absorbers consisting of a metamaterial layer, dielectric spacer, and ground plane are specifically considered. Using interference theory, the dielectric spacer thickness and resonant frequency for unity absorption can be numerically determined from the functional dependence of the relative phase shift of the total reflection. Further, using transmission line theory in combination with interference theory we obtain analytical expressions for the unity absorption resonance frequency and corresponding spacer layer thickness in terms of the bare resonant frequency of the metamaterial layer and metallic and dielectric losses within the absorber structure. These simple expressions reveal a redshift of the unity absorption frequency with increasing loss that, in turn, necessitates an increase in the thickness of the dielectric spacer. The results of our analysis are experimentally confirmed by performing reflection-based terahertz time-domain spectroscopy on fabricated absorber structures covering a range of dielectric spacer thicknesses with careful control of the loss accomplished through water absorption in a semiporous polyimide dielectric spacer. Our findings can be widely applied to guide the design and optimization of the metamaterial absorbers and sensors.

  7. High-Temperature High-Efficiency Solar Thermoelectric Generators

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Quantum Junction Solar Cells

    KAUST Repository

    Tang, Jiang

    2012-09-12

    Colloidal quantum dot solids combine convenient solution-processing with quantum size effect tuning, offering avenues to high-efficiency multijunction cells based on a single materials synthesis and processing platform. The highest-performing colloidal quantum dot rectifying devices reported to date have relied on a junction between a quantum-tuned absorber and a bulk material (e.g., TiO 2); however, quantum tuning of the absorber then requires complete redesign of the bulk acceptor, compromising the benefits of facile quantum tuning. Here we report rectifying junctions constructed entirely using inherently band-aligned quantum-tuned materials. Realizing these quantum junction diodes relied upon the creation of an n-type quantum dot solid having a clean bandgap. We combine stable, chemically compatible, high-performance n-type and p-type materials to create the first quantum junction solar cells. We present a family of photovoltaic devices having widely tuned bandgaps of 0.6-1.6 eV that excel where conventional quantum-to-bulk devices fail to perform. Devices having optimal single-junction bandgaps exhibit certified AM1.5 solar power conversion efficiencies of 5.4%. Control over doping in quantum solids, and the successful integration of these materials to form stable quantum junctions, offers a powerful new degree of freedom to colloidal quantum dot optoelectronics. © 2012 American Chemical Society.

  9. Neutron absorbed dose in a pacemaker CMOS

    International Nuclear Information System (INIS)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L.

    2012-01-01

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10 -17 Gy per neutron emitted by the source. (Author)

  10. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: fermineutron@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-06-15

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10{sup -17} Gy per neutron emitted by the source. (Author)

  11. Tribology Aspect of Rubber Shock Absorbers Development

    Directory of Open Access Journals (Sweden)

    M. Banić

    2013-09-01

    Full Text Available Rubber is a very flexible material with many desirable properties Which enable its broad use in engineering practice. Rubber or rubber-metal springs are widely used as anti-vibration or anti-shock components in technical systems. Rubber-metal springs are usually realized as a bonded assembly, however especially in shock absorbers, it is possible to realize free contacts between rubber and metal parts. In previous research it authors was observed that friction between rubber and metal in such case have a significant influence on the damping characteristics of shock absorber. This paper analyzes the development process of rubber or rubber-metal shock absorbers realized free contacts between the constitutive parts, starting from the design, construction, testing and operation, with special emphasis on the development of rubber-metal springs for the buffing and draw gear of railway vehicles.

  12. Quantum walk with one variable absorbing boundary

    International Nuclear Information System (INIS)

    Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli

    2017-01-01

    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks. - Highlights: • A novel scheme about quantum walk with variable boundary is proposed. • The analytical results of the survival probability from the absorbing boundary. • The behavior of survival probability under different boundary conditions. • The influence of different initial coin states on the survival probability.

  13. A wideband absorber for television studios

    Science.gov (United States)

    Baird, M. D. M.

    The acoustic treatment in BBC television has taken various forms to date, all of which have been relatively expensive, some of which provide inadequate absorption. An investigation has been conducted into the possibilities of producing a new type of wideband absorber which would be more economic, also taking installation time into account, than earlier designs. This Report describes the absorption coefficient measurements made on various combinations of materials, from which a wideband sound absorber has been developed. The absorber works efficiently between 50 Hz and 10 kHz, is simple and easy to construct using readily available materials, and is fire resistant. The design lends itself, if necessary, to on-site fine tuning, and savings in the region of 50 percent can be achieved in terms of cost and space with respect to previous designs.

  14. Ferrite HOM Absorber for the RHIC ERL

    Energy Technology Data Exchange (ETDEWEB)

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  15. Aluminum alloy excellent in neutron absorbing performance

    International Nuclear Information System (INIS)

    Iida, Tetsuya; Tamamura, Tadao; Morimoto, Hiroyuki; Ouchi, Ken-ichiro.

    1987-01-01

    Purpose: To obtain structural materials made of aluminum alloys having favorable neutron absorbing performance and excellent in the performance as structural materials such as processability and strength. Constitution: Powder of Gd 2 O 3 as a gadolinium compound or metal gadolinium is uniformly mixed with the powder of aluminum or aluminum alloy. The amount of the gadolinium compound added is set to 0.1 - 30 % by weight. No sufficient neutron absorbing performance can be obtained if it is less than 0.1 % by weight, whereas the processability and mechanical property of the alloy are degraded if it exceeds 30 % by weight. Further, the grain size is set to less about 50 μm. Further, since the neutron absorbing performance varies greatly if the aluminum powder size exceeds 100 μm, the diameter is set to less than about 100 μm. These mixtures are molded in a hot press. This enables to obtain aimed structural materials. (Takahashi, M.)

  16. High-flux solar concentration with imaging designs

    Energy Technology Data Exchange (ETDEWEB)

    Feuermann, D. [Ben-Gurion University of the Negev (Israel). Jacob Blaustein Institute for Desert Research; Gordon, J.M. [Ben-Gurion University of the Negev (Israel). Jacob Blaustein Institute for Desert Research; Ben-Gurion University of the Negev (Israel). Dept. of Mechanical Engineering; Ries, H. [Ries and Partners, Munich (Germany)

    1999-02-01

    Most large solar concentrators designed for high flux concentration at high collection efficiency are based on imaging primary mirrors and nonimaging secondary concentrators. In this paper, we offer an alternative purely imaging two-stage solar concentrator that can attain high flux concentration at high collection efficiency. Possible practical virtues include: (1) an inherent large gap between absorber and secondary mirror; (2) a restricted angular range on the absorber; and (3) an upward-facing receiver where collected energy can be extracted via the (shaded) apex of the parabola. We use efficiency-concentration plots to characterize the solar concentrators considered, and to evaluate the potential improvements with secondary concentrators. (author)

  17. Solar energy

    International Nuclear Information System (INIS)

    Kruisheer, N.

    1992-01-01

    In five brief articles product information is given on solar energy applications with special attention to the Netherlands. After an introduction on solar energy availability in the Netherlands the developments in solar boiler techniques are dealt with. Solar water heaters have advantages for the environment, and government subsidies stimulate different uses of such water heaters. Also the developments of solar cells show good prospects, not only for developing countries, but also for the industrialized countries. In brief the developments in solar energy storage and the connection of solar equipment to the grid are discussed. Finally attention is paid to the applications of passive solar energy in the housing construction, the use of transparent thermal insulation and the developments of translucent materials. 18 figs., 18 ills

  18. Solar Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar photographic and illustrated datasets contributed by a number of national and private solar observatories located worldwide....

  19. Solar Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar feature datasets contributed by a number of national and private solar observatories located worldwide.

  20. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  1. Fabrication of CIS Absorber Layers with Different Thicknesses Using A Non-Vacuum Spray Coating Method

    Directory of Open Access Journals (Sweden)

    Chien-Chen Diao

    2014-01-01

    Full Text Available In this study, a new thin-film deposition process, spray coating method (SPM, was investigated to deposit the high-densified CuInSe2 absorber layers. The spray coating method developed in this study was a non-vacuum process, based on dispersed nano-scale CuInSe2 precursor and could offer a simple, inexpensive, and alternative formation technology for CuInSe2 absorber layers. After spraying on Mo/glass substrates, the CuInSe2 thin films were annealed at 550 °C by changing the annealing time from 5 min to 30 min in a selenization furnace, using N2 as atmosphere. When the CuInSe2 thin films were annealed, without extra Se or H2Se gas used as the compensation source during the annealing process. The aim of this project was to investigate the influence of annealing time on the densification and crystallization of the CuInSe2 absorber layers to optimize the quality for cost effective solar cell production. The thickness of the CuInSe2 absorber layers could be controlled as the volume of used dispersed CuInSe2-isopropyl alcohol solution was controlled. In this work, X-ray diffraction patterns, field emission scanning electron microscopy, and Hall parameter measurements were performed in order to verify the quality of the CuInSe2 absorber layers obtained by the Spray Coating Method.

  2. The MIRD method of estimating absorbed dose

    International Nuclear Information System (INIS)

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine

  3. Absorbed Energy in Ship Collisions and Grounding

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    is that the absorbed energy does not depend on the arrangement of the structure, the material properties, and the damage mode.The purpose of the present paper is to establish a new simple relation between the absorbed energy and the destroyed material volume, which can be used as a design tool for analysis of ship...... collisions and grounding. The developed expressions reflect the structural arrangement, the material properties and different damage patterns.The present method is validated against a large number of existing experimental results and detailed numerical simulation results. Applications to full-sale ship...

  4. Method for manufacture of neutron absorbing articles

    International Nuclear Information System (INIS)

    Owens, D.

    1980-01-01

    A one-step curing method for the manufacture of a neutron absorbing article which comprises irreversibly curing, in desired article form, a form-retaining mixture of boron carbide particles, curable phenolic resin in solid state and in particula te form and a minor proportion of a liquid medium, which boils at a temperature below 200*c., at an elevated temperature so as to obtain bonding of the irreversibly cured phenolic polymer resulting to the boron carbide particles and production of the neutron absorbing article in desired form

  5. LINEAR MODEL FOR NON ISOSCELES ABSORBERS.

    Energy Technology Data Exchange (ETDEWEB)

    BERG,J.S.

    2003-05-12

    Previous analyses have assumed that wedge absorbers are triangularly shaped with equal angles for the two faces. In this case, to linear order, the energy loss depends only on the position in the direction of the face tilt, and is independent of the incoming angle. One can instead construct an absorber with entrance and exit faces facing rather general directions. In this case, the energy loss can depend on both the position and the angle of the particle in question. This paper demonstrates that and computes the effect to linear order.

  6. Optically Modulated Multiband Terahertz Perfect Absorber

    DEFF Research Database (Denmark)

    Seren, Huseyin R.; Keiser, George R.; Cao, Lingyue

    2014-01-01

    response of resonant metamaterials continues to be a challengingendeavor. Resonant perfect absorbers have flourished as one of the mostpromising metamaterial devices with applications ranging from power har-vesting to terahertz imaging. Here, an optically modulated resonant perfectabsorber is presented....... Utilizing photo-excited free carriers in silicon padsplaced in the capacitive gaps of split ring resonators, a dynamically modu-lated perfect absorber is designed and fabricated to operate in reflection.Large modulation depth (38% and 91%) in two absorption bands (with 97%and 92% peak absorption...

  7. Multilayer detector for skin absorbed dose measuring

    International Nuclear Information System (INIS)

    Osanov, D.P.; Panova, V.P.; Shaks, A.I.

    1985-01-01

    A method for skin dosimetry based on utilization of multilayer detectors and permitting to estimate distribution of absorbed dose by skin depth is described. The detector represents a set of thin sensitive elements separated by tissue-equivalent absorbers. Quantitative evaluation and forecasting the degree of radiation injury of skin are determined by the formula based on determination of the probability of the fact that cells are not destroyed and they can divide further on. The given method ensures a possibility of quantitative evaluation of radiobiological effect and forecasting clinical consequences of skin irradiation by results of corresponding measurements of dose by means of the miultilayer detector

  8. Device for absorbing seismic effects on buildings

    International Nuclear Information System (INIS)

    Xercavins, Pierre; Pompei, Michel.

    1979-01-01

    Device for absorbing seismic effects. The construction or structure to be protected rests on its foundations through at least one footing formed of a stack of metal plates interlinked by layers of adhesive material, over at least a part of their extent, this material being an elastomer that can distort, characterized in that at least part of the area of some metal plates works in association with components which are able to absorb at least some of the energy resulting from friction during the relative movements of the metal plates against the distortion of the elastomer [fr

  9. On the radiative effects of light-absorbing impurities on snowpack evolution

    Science.gov (United States)

    Dumont, M.; Tuzet, F.; Lafaysse, M.; Arnaud, L.; Picard, G.; Lejeune, Y.; Lamare, M.; Morin, S.; Voisin, D.; Di Mauro, B.

    2017-12-01

    The presence of light absorbing impurities in snow strongly decreases snow reflectance leading to an increase in the amount of solar energy absorbed by the snowpack. This effect is also known as impurities direct radiative effect. The change in the amount of energy absorbed by the snowpack modifies the temperature profile inside the snowpack and in turn snow metamorphism (impurities indirect radiative effects). In this work, we used the detailed snowpack model SURFEX/ISBA-Crocus with an explicit representation of snow light-absorbing impurities content (Tuzet et al., 2017) fed by medium-resolution ALADIN-Climate atmospheric model to represent dust and black carbon atmospheric deposition fluxes. The model is used at two sites: Col de Porte (medium elevation site in the French Alps) and Torgnon (high elevation site in the Italian Alps). The simulations are compared to in-situ observations and used to quantify the effects of light-absorbing impurities on snow melt rate and timing. The respective parts of the direct and indirect radiative effects of light-absorbing impurities in snow are also computed for the two sites, emphasizing the need to account for the interactions between snow metamorphism and LAI radiative properties, to accurately predict the effects of light-absorbing impurities in snow. Moreover, we describe how automated hyperspectral reflectance can be used to estimate effective impurities surface content in snow. Finally we demonstrate how these reflectances measurements either from in situ or satellite data can be used via an assimilation scheme to constrain snowpack ensemble simulations and better predict the snowpack state and evolution.

  10. Solar Special

    International Nuclear Information System (INIS)

    Van Roekel, A.; Osborne, J.; Schroeter, S.; De Jong, R.; De Saint Jacob, Y.

    2009-01-01

    Solar power is growing much faster than most policymakers and analysts realise. As costs come down and feed-in tariffs go up across Europe, a number of countries have started in pursuit of market leader Germany. But in Germany criticism is growing of the multi-billion-euro support schemes that keep the solar industry booming. In this section of the magazine several articles are dedicated to developments in solar energy in Europe. The first article is an overview story on the strong growing global market for solar cells, mainly thanks to subsidy schemes. The second article is on the position of foreign companies in the solar market in Italy. Article number three is dedicated to the conditions for solar technology companies to establish themselves in the German state of Saxony. Also the fifth article deals with the development of solar cells in Saxony: scientists, plant manufacturers and module producers in Saxony are working on new technologies that can be used to produce solar electricity cost-effectively. The goal is to bring the price down to match that of conventionally generated electricity within the next few years. The sixth article deals with the the solar power market in Belgium, which may be overheated or 'oversubsidized'. Article seven is on France, which used to be a pioneer in solar technology, but now produces only a fraction of the solar output of market leader Germany. However, new attractive feed-in-tariffs are changing the solar landscape drastically

  11. MINIMUM MAINTENANCE SOLAR PUMP Abebayehu Assefa ...

    African Journals Online (AJOL)

    increase the performance of the solar pump, by trapping the long-wave light rays leaving the absorber - the water tank, two glass covers have been employed. .... Absorptivity of panel. 0.95. Transmissivity of glass. 0.90. Volume of tank. 0.202 m 3. (15). (14) mwev -. Vv. The pumping head of water is determined from Eq.

  12. Equipment for increasing the efficiency of a CPC-solar energy collector

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Bei Tse; Rabl, Ari

    1977-01-13

    The invention concerns a cylindrical reflector with concentrators, which concentrate the solar radiation on a small surface, in whose area the actual absorber is fitted. To improve the efficiency of the collector there is provision for using the solar energy absorbed by the reflecting walls. For this purpose conducting channels are fitted on the back of the reflectors, through which a heat transport medium flows and takes away the absorbed energy. This energy can be used directly or the channels can be connected in series with the main absorber.

  13. Intermixing at the absorber-buffer layer interface in thin-film solar cells: The electronic effects of point defects in Cu(In,Ga)(Se,S){sub 2} and Cu{sub 2}ZnSn(Se,S){sub 4} devices

    Energy Technology Data Exchange (ETDEWEB)

    Varley, J. B.; Lordi, V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2014-08-14

    We investigate point defects in the buffer layers CdS and ZnS that may arise from intermixing with Cu(In,Ga)(S,Se){sub 2} (CIGS) or Cu{sub 2}ZnSn(S,Se){sub 4} (CZTS) absorber layers in thin-film photovoltaics. Using hybrid functional calculations, we characterize the electrical and optical behavior of Cu, In, Ga, Se, Sn, Zn, Na, and K impurities in the buffer. We find that In and Ga substituted on the cation site act as shallow donors in CdS and tend to enhance the prevailing n-type conductivity at the interface facilitated by Cd incorporation in CIGS, whereas they are deep donors in ZnS and will be less effective dopants. Substitutional In and Ga can favorably form complexes with cation vacancies (A-centers) which may contribute to the “red kink” effect observed in some CIGS-based devices. For CZTS absorbers, we find that Zn and Sn defects substituting on the buffer cation site are electrically inactive in n-type buffers and will not supplement the donor doping at the interface as in CIGS/CdS or ZnS devices. Sn may also preferentially incorporate on the S site as a deep acceptor in n-type ZnS, which suggests possible concerns with absorber-related interfacial compensation in CZTS devices with ZnS-derived buffers. Cu, Na, and K impurities are found to all have the same qualitative behavior, most favorably acting as compensating acceptors when substituting on the cation site. Our results suggest one beneficial role of K and Na incorporation in CIGS or CZTS devices is the partial passivation of vacancy-related centers in CdS and ZnS buffers, rendering them less effective interfacial hole traps and recombination centers.

  14. Solar Indices - Solar Radio Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  15. The Cooling of a Liquid Absorber using a Small Cooler

    International Nuclear Information System (INIS)

    Baynham, D.E.; Bradshaw, T.W.; Green, M.A.; Ishimoto, S.; Liggins, N.

    2005-01-01

    This report discusses the use of small cryogenic coolers for cooling the Muon Ionization Cooling Experiment (MICE) liquid cryogen absorbers. Since the absorber must be able contain liquid helium as well liquid hydrogen, the characteristics of the available 4.2 K coolers are used here. The issues associated with connecting two-stage coolers to liquid absorbers are discussed. The projected heat flows into an absorber and the cool-down of the absorbers using the cooler are presented. The warm-up of the absorber is discussed. Special hydrogen safety issues that may result from the use of a cooler on the absorbers are also discussed

  16. ADAPTIVE OPTICS IMAGING OF A MASSIVE GALAXY ASSOCIATED WITH A METAL-RICH ABSORBER

    International Nuclear Information System (INIS)

    Chun, Mark R.; Kulkarni, Varsha P.; Gharanfoli, Soheila; Takamiya, Marianne

    2010-01-01

    The damped and sub-damped Lyα absorption (DLA and sub-DLA) line systems in quasar spectra are believed to be produced by intervening galaxies. However, the connection of quasar absorbers to galaxies is not well-understood, since attempts to image the absorbing galaxies have often failed. While most DLAs appear to be metal poor, a population of metal-rich absorbers, mostly sub-DLAs, has been discovered in recent studies. Here we report high-resolution K-band imaging with the Keck laser guide star adaptive optics (LGSAO) system of the field of quasar SDSSJ1323-0021 in search of the galaxy producing the z = 0.72 sub-DLA absorber. With a metallicity of 2-4 times the solar level, this absorber is one of the most metal-rich systems found to date. Our data show a large bright galaxy with an angular separation of only 1.''25 from the quasar, well-resolved from the quasar at the high resolution of our data. The galaxy has a magnitude of K = 17.6-17.9, which corresponds to a luminosity of ∼3-6 L*. Morphologically, the galaxy is fitted with a model with an effective radius, enclosing half of the total light, of R e = 4 kpc and a bulge-to-total ratio of 0.4-1.0, indicating a substantial bulge stellar population. Based on the mass-metallicity relation of nearby galaxies, the absorber galaxy appears to have a stellar mass of ∼>10 11 M sun . Given the small impact parameter (9.0 kpc at the absorber redshift), this massive galaxy appears to be responsible for the metal-rich sub-DLA. The absorber galaxy is consistent with the metallicity-luminosity relation observed for nearby galaxies, but is near the upper end of metallicity. Our study marks the first application of LGSAO for the study of the structure of galaxies producing distant quasar absorbers. Finally, this study offers the first example of a massive galaxy with a substantial bulge producing a metal-rich absorber.

  17. Workshop Report on Managing Solar Radiation

    Science.gov (United States)

    Lane, Lee (Compiler); Caldeira, Ken (Compiler); Chatfield, Robert (Compiler); Langhoff, Stephanie (Compiler)

    2007-01-01

    The basic concept of managing Earth's radiation budget is to reduce the amount of incoming solar radiation absorbed by the Earth so as to counterbalance the heating of the Earth that would otherwise result from the accumulation of greenhouse gases. The workshop did not seek to decide whether or under what circumstances solar radiation management should be deployed or which strategies or technologies might be best, if it were deployed. Rather, the workshop focused on defining what kinds of information might be most valuable in allowing policy makers more knowledgeably to address the various options for solar radiation management.

  18. Silicon nanowire-based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Stelzner, Th; Pietsch, M; Andrae, G; Falk, F; Ose, E; Christiansen, S [Institute of Photonic Technology, Albert-Einstein-Strasse 9, D-07745 Jena (Germany)], E-mail: thomas.stelzner@ipht-jena.de

    2008-07-23

    The fabrication of silicon nanowire-based solar cells on silicon wafers and on multicrystalline silicon thin films on glass is described. The nanowires show a strong broadband optical absorption, which makes them an interesting candidate to serve as an absorber in solar cells. The operation of a solar cell is demonstrated with n-doped nanowires grown on a p-doped silicon wafer. From a partially illuminated area of 0.6 cm{sup 2} open-circuit voltages in the range of 230-280 mV and a short-circuit current density of 2 mA cm{sup -2} were obtained.

  19. Silicon nanowire-based solar cells

    International Nuclear Information System (INIS)

    Stelzner, Th; Pietsch, M; Andrae, G; Falk, F; Ose, E; Christiansen, S

    2008-01-01

    The fabrication of silicon nanowire-based solar cells on silicon wafers and on multicrystalline silicon thin films on glass is described. The nanowires show a strong broadband optical absorption, which makes them an interesting candidate to serve as an absorber in solar cells. The operation of a solar cell is demonstrated with n-doped nanowires grown on a p-doped silicon wafer. From a partially illuminated area of 0.6 cm 2 open-circuit voltages in the range of 230-280 mV and a short-circuit current density of 2 mA cm -2 were obtained

  20. Solar receiver with integrated optics

    Science.gov (United States)

    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.

  1. Review of Plasmonic Nanocomposite Metamaterial Absorber

    Directory of Open Access Journals (Sweden)

    Mehdi Keshavarz Hedayati

    2014-02-01

    Full Text Available Plasmonic metamaterials are artificial materials typically composed of noble metals in which the features of photonics and electronics are linked by coupling photons to conduction electrons of metal (known as surface plasmon. These rationally designed structures have spurred interest noticeably since they demonstrate some fascinating properties which are unattainable with naturally occurring materials. Complete absorption of light is one of the recent exotic properties of plasmonic metamaterials which has broadened its application area considerably. This is realized by designing a medium whose impedance matches that of free space while being opaque. If such a medium is filled with some lossy medium, the resulting structure can absorb light totally in a sharp or broad frequency range. Although several types of metamaterials perfect absorber have been demonstrated so far, in the current paper we overview (and focus on perfect absorbers based on nanocomposites where the total thickness is a few tens of nanometer and the absorption band is broad, tunable and insensitive to the angle of incidence. The nanocomposites consist of metal nanoparticles embedded in a dielectric matrix with a high filling factor close to the percolation threshold. The filling factor can be tailored by the vapor phase co-deposition of the metallic and dielectric components. In addition, novel wet chemical approaches are discussed which are bio-inspired or involve synthesis within levitating Leidenfrost drops, for instance. Moreover, theoretical considerations, optical properties, and potential application of perfect absorbers will be presented.

  2. Moving core beam energy absorber and converter

    Science.gov (United States)

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  3. Can polar bear hairs absorb environmental energy?

    Directory of Open Access Journals (Sweden)

    He Ji-Huan

    2011-01-01

    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  4. Shock absorbing structure for nuclear fuel assemblies

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1981-01-01

    A hydraulic apparatus is described that absorbs shocks that may be applied to fuel assemblies. Spring pads mounted on the upper end fittings of the fuel assemblies have plungers that move within hollow guide posts attached to the upper grids of the fuel assemblies. (L.L.)

  5. Proposal concerning the absorbed dose conversion factor

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, A [National Inst. of Radiological Sciences, Chiba (Japan)

    1978-03-01

    New definitions of the absorbed dose conversion factors Csub(lambda) and Csub(E) are proposed. The absorbed dose in water is given by the product of absorbed dose conversion factor, exposure calibration factor, ionisation chamber reading, cap displacement correction factor and perturbation correction factor. At exposure calibration the material of the build-up cap must be the same as that of the chamber wall. An ionisation chamber of which the wall material is water-equivalent or air-equivalent may be used. In the latter case the wall must be thin. For these two cases absorbed dose conversion factors are introduced and it is recommended that either of the two sets should be adopted. Furthermore, if the chamber wall is neither water- nor air-equivalent, the factor by which these currently defined values should be multiplied is also given: again the wall must be thin. The ICRU definitions of Csub(lambda) and Csub(E) are inconsistent, as recently pointed out, while the definitions presented here are consistent.

  6. Strain absorbent modules for cavity filling

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    Strain absorbent modules made from weldmesh panels and helical steel binders can be used, together with timber packing, to support the roof and sides of cavities instead of softwood and hardwood nogs. A description of these modules and a series of load tests and underground trials carried out on the modules is given.

  7. Measuring the absorbed radioactivity during a flight

    International Nuclear Information System (INIS)

    2002-01-01

    This paper presents the new system SIEVERT developed by the General Direction of the Civil Aviation (DGAC) to measure the radiations doses absorbed from cosmic radiation. The system is available on the Internet site: www.sievert-system.org. (A.L.B.)

  8. Electromagnetic and microwave absorbing properties of hollow ...

    Indian Academy of Sciences (India)

    bandwidth below −10 dB and minimum RL decrease with increasing thickness of HCNSs/paraffin composites. Keywords. Nanomaterials; nanospheres; CVD; electric; magnetic; microwave absorption properties. 1. Introduction. In recent years, microwave absorbing materials have attracted considerable attention because it ...

  9. Coupler for nuclear reactor absorber rods

    International Nuclear Information System (INIS)

    Kerz, K.

    1984-01-01

    A coupler is described for absorber rods being suspended during operation of nuclear reactors which includes plurality of actuating elements being movable for individually and jointly releasing the coupler, the movement of each of the actuating elements for releasing the coupler being independently controllable

  10. Optically Transparent Thermally Insulating Silica Aerogels for Solar Thermal Insulation.

    Science.gov (United States)

    Günay, A Alperen; Kim, Hannah; Nagarajan, Naveen; Lopez, Mateusz; Kantharaj, Rajath; Alsaati, Albraa; Marconnet, Amy; Lenert, Andrej; Miljkovic, Nenad

    2018-04-18

    Rooftop solar thermal collectors have the potential to meet residential heating demands if deployed efficiently at low solar irradiance (i.e., 1 sun). The efficiency of solar thermal collectors depends on their ability to absorb incoming solar energy and minimize thermal losses. Most techniques utilize a vacuum gap between the solar absorber and the surroundings to eliminate conduction and convection losses, in combination with surface coatings to minimize reradiation losses. Here, we present an alternative approach that operates at atmospheric pressure with simple, black, absorbing surfaces. Silica based aerogels coated on black surfaces have the potential to act as simple and inexpensive solar thermal collectors because of their high transmission to solar radiation and low transmission to thermal radiation. To demonstrate their heat-trapping properties, we fabricated tetramethyl orthosilicate-based silica aerogels. A hydrophilic aerogel with a thickness of 1 cm exhibited a solar-averaged transmission of 76% and thermally averaged transmission of ≈1% (at 100 °C). To minimize unwanted solar absorption by O-H groups, we functionalized the aerogel to be hydrophobic, resulting in a solar-averaged transmission of 88%. To provide a deeper understanding of the link between aerogel properties and overall efficiency, we developed a coupled radiative-conductive heat transfer model and used it to predict solar thermal performance. Instantaneous solar thermal efficiencies approaching 55% at 1 sun and 80 °C were predicted. This study sheds light on the applicability of silica aerogels on black coatings for solar thermal collectors and offers design priorities for next-generation solar thermal aerogels.

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

    Science.gov (United States)

    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.

  12. Thermo-economic performance of inclined solar water distillation systems

    Directory of Open Access Journals (Sweden)

    Agboola Phillips O.

    2015-01-01

    Full Text Available This study investigates the thermo-economic performance of different configurations of inclined solar water desalination for parameters such as daily production, efficiency, system cost and distilled water production cost. The four different configurations considered for this study are as follows; 1. Inclined solar water distillation with bare absorber plate (IISWD with daily production of 5.46 kg/m2 day and daily efficiency of 48.3%. 2. Inclined solar water distillation with wick on absorber plate (IISWDW with daily production of 6.41kg/m2 day and daily efficiency 50.3%. 3. Inclined solar water distillation with wire mesh on absorber plate (IISWDWM with daily production n of 3.03 kg/m2 day and daily efficiency 32.6%. 4. Inclined solar water distillation with bare absorber plate (ISWD. (Control System with daily production of 3.25 kg/m2 day and daily efficiency of 40.1%. The systems potable water cost price ranges from 0.03 $/L for IISWDW to 0.06$/L for IISWDWM System. All the systems are economically and technically feasible as a solar distillation system for potable water in Northern Cyprus. The price of potable water from water vendors/hawkers ranges from 0.11-0.16 $/L. It is more economically viable to have the rooftop inclined solar water desalination system than procuring potable water from vendors.`

  13. Coupled solar still, solar heater

    Energy Technology Data Exchange (ETDEWEB)

    Davison, R R; Harris, W B; Moor, D H; Delyannis, A; Delyannis, E [eds.

    1976-01-01

    Computer simulation of combinations of solar stills and solar heaters indicates the probable economic advantage of such an arrangement in many locations if the size of the heater is optimized relative to that of the still. Experience with various low cost solar heaters is discussed.

  14. Numerical study on the effects of absorptivity on performance of flat plate solar collector of a water heater

    Science.gov (United States)

    Tambunan, D. R. S.; Sibagariang, Y. P.; Ambarita, H.; Napitupulu, F. H.; Kawai, H.

    2018-03-01

    The characteristics of absorber plate of a flat plate solar collector play an important role in the improvement of the performance. In this work, a numerical analysis is carried out to explore the effect of absorptivity and emissivity of absorber plate to the performance of the solar collector of a solar water heater. For a results comparison, a simple a simple solar box cooker with absorber area of 0.835 m × 0.835 m is designed and fabricated. It is employed to heat water in a container by exposing to the solar radiation in Medan city of Indonesia. The transient governing equations are developed. The governing equations are discretized and solved using the forward time step marching technique. The results reveal that the experimental and numerical results show good agreement. The absorptivity of the plate absorber and emissivity of the glass cover strongly affect the performance of the solar collector.

  15. Solar Sailing

    Science.gov (United States)

    Johnson, Les

    2009-01-01

    Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.

  16. Simulation of Hybrid Solar Dryer

    International Nuclear Information System (INIS)

    Yunus, Y M; Al-Kayiem, H H

    2013-01-01

    The efficient performance of a solar dryer is mainly depending on the good distribution of the thermal and flow field inside the dryer body. This paper presents simulation results of a solar dryer with a biomass burner as backup heater. The flow and thermal fields were simulated by CFD tools under different operational modes. GAMBIT software was used for the model and grid generation while FLUENT software was used to simulate the velocity and temperature distribution inside the dryer body. The CFD simulation procedure was validated by comparing the simulation results with experimental measurement. The simulation results show acceptable agreement with the experimental measurements. The simulations have shown high temperature spot with very low velocity underneath the solar absorber and this is an indication for the poor design. Many other observations have been visualized from the temperature and flow distribution which cannot be captured by experimental measurements.

  17. Neutron absorbers and methods of forming at least a portion of a neutron absorber

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, Donna P; Porter, Douglas L; Swank, W David; Erickson, Arnold W

    2014-12-02

    Methods of forming at least a portion of a neutron absorber include combining a first material and a second material to form a compound, reducing the compound into a plurality of particles, mixing the plurality of particles with a third material, and pressing the mixture of the plurality of particles and the third material. One or more components of neutron absorbers may be formed by such methods. Neutron absorbers may include a composite material including an intermetallic compound comprising hafnium aluminide and a matrix material comprising pure aluminum.

  18. Evaluation of a tracking flat-plate solar collector in Brazil

    International Nuclear Information System (INIS)

    Maia, Cristiana B.; Ferreira, André G.; Hanriot, Sérgio M.

    2014-01-01

    The continuing research for an alternative power source due to the perceived scarcity of fuel fossils has, in recent years, given solar energy a remarkable edge. Nevertheless, the Earth's daily and seasonal movement affects the intensity of the incident solar radiation. Devices can track the sun in order to ensure optimum positions with regard to incident solar radiation, maximizing the absorbed solar energy, and the useful energy gain. In this paper, a mathematical model is developed to estimate the solar radiation absorbed, the useful energy gain, and the efficiency of a flat-plate solar collector in Brazil. The results for a sun tracking flat-plate solar collector were compared to fixed devices. The full tracking system with rotation about two axes presented higher absorbed energy, when compared to the rotation about a single axe and to a fixed collector. Also, it was shown that the tilt angle for a fixed solar collector does not cause significant variations in the useful energy gain or in the absorbed solar radiation, for the same azimuth angle. - Highlights: • A model was developed for solar radiation based on experimental data for K T . • Useful energy gain and efficiency of a flat-plate solar collector were evaluated for a one-year period. • Several sun tracking systems were compared to fixed devices. • Tilt angle for a fixed device does not significantly affect the useful energy gain

  19. Climate hypersensitivity to solar forcing?

    Directory of Open Access Journals (Sweden)

    W. Soon

    2000-05-01

    Full Text Available We compare the equilibrium climate responses of a quasi-dynamical energy balance model to radiative forcing by equivalent changes in CO2, solar total irradiance (Stot and solar UV (SUV. The response is largest in the SUV case, in which the imposed UV radiative forcing is preferentially absorbed in the layer above 250 mb, in contrast to the weak response from global-columnar radiative loading by increases in CO2 or Stot. The hypersensitive response of the climate system to solar UV forcing is caused by strongly coupled feedback involving vertical static stability, tropical thick cirrus ice clouds and stratospheric ozone. This mechanism offers a plausible explanation of the apparent hypersensitivity of climate to solar forcing, as suggested by analyses of recent climatic records. The model hypersensitivity strongly depends on climate parameters, especially cloud radiative properties, but is effective for arguably realistic values of these parameters. The proposed solar forcing mechanism should be further confirmed using other models (e.g., general circulation models that may better capture radiative and dynamical couplings of the troposphere and stratosphere.Key words: Meteorology and atmospheric dynamics (climatology · general or miscellaneous · Solar physics · astrophysics · and astronomy (ultraviolet emissions

  20. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.