Absorber

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 118677 Experts worldwide ranked by ideXlab platform

J L Bhagoria - One of the best experts on this subject based on the ideXlab platform.

  • heat loss study of trapezoidal cavity Absorbers for linear solar concentrating collector
    Energy Conversion and Management, 2010
    Co-Authors: Panna Lal Singh, R M Sarviya, J L Bhagoria
    Abstract:

    Abstract There should be minimum heat loss from the Absorber to achieve better efficiency of the solar collector. Overall heat loss coefficients of the trapezoidal cavity Absorber with rectangular and round pipe were studied in the laboratory. Two identical rectangular pipe Absorbers (section size: 100 × 23 mm, thickness: 2.5 mm and length 2170 mm) and two round pipe Absorbers (a set of six mild steel round tubes of 16 mm diameter and 2.5 mm thickness brazed together in single layer making 100 mm width) were fabricated. A rectangular and a round pipe were painted with ordinary mat black paint (emissivity at 100 °C = 0.91) and one pipe of each type was coated with black nickel selective surface (emissivity at 100 °C = 0.17). Overall heat loss coefficient of the Absorber was studied by circulating hot oil through it at different temperatures. The heat loss coefficient was increased with the Absorber temperature. The heat loss coefficients for ordinary black coated and selective surface coated round pipe Absorbers were varied from 3.5 to 7.5 W/m 2 /°C and 2.7–5.8 W/m 2 /°C respectively. The rectangular pipe section has marginally higher heat loss coefficients as compared to round pipe Absorber. Selective surface coating on the Absorbers reduced heat loss coefficient significantly by 20–30% as compared to ordinary black coating. The double glass cover also reduced heat loss coefficient by 10–15% as compared to single glass cover. The overall heat loss coefficients were also estimated analytically by parallel plate correlation and cavity correlations. The trend of variation of estimated heat loss coefficients by both methods was similar to experimental values. However, estimated values by cavity correlation were closure and uniformly distributed at all temperature range.

  • thermal performance of linear fresnel reflecting solar concentrator with trapezoidal cavity Absorbers
    Applied Energy, 2010
    Co-Authors: Panna Lal Singh, R M Sarviya, J L Bhagoria
    Abstract:

    Thermal performance of the four identical trapezoidal cavity Absorbers for linear Fresnel reflecting solar device were studied and compared. The Absorbers were designed for operating in conjunction with a prototype Fresnel solar reflector. Rectangular and round pipe sections were used as Absorber by placing in the trapezoidal cavity. The Absorber pipes were coated with ordinary dull black board paint and black nickel selective surface. The bottom of the cavity was provided with plane glass to allow the solar radiation to be reflected from the Fresnel reflector. The other three sides of the cavity Absorber were insulated to reduce heat loss. Thermal performance of the Fresnel reflecting concentrator with each trapezoidal cavity Absorber was studied experimentally at different concentration ratio of the reflector. The study revealed that the thermal efficiency was influenced by the concentration ratio and selective surface coating on the Absorber. The thermal efficiency decreased with the increase in the concentration ratio of the Fresnel reflecting collector. The selective surface coated Absorber had a significant advantage in terms of superior thermal performance as compared to ordinary black painted Absorber. The round pipe (multi-tube) receiver had higher surface area to absorb solar energy as compared to rectangular pipe receiver. Thermal efficiency of the solar device with round pipe Absorber was found higher (up to 8%) as compared to rectangular pipe Absorber.

Shin Yoshikado - One of the best experts on this subject based on the ideXlab platform.

  • effect of sendust particle size on absorption characteristics of composite electromagnetic wave Absorber
    Key Engineering Materials, 2009
    Co-Authors: K Sakai, Yuuki Sato, Yoichi Wada, Shin Yoshikado
    Abstract:

    The effects of the particle size of sendust, which is an alloy of Al 5%, Si 10%, and Fe 85%, on the absorption characteristics of composite electromagnetic wave Absorbers made of polystyrene resin and sendust were investigated in the frequency range from 1 to 40 GHz. The size of sendust particles was varied between approximately 5 and 20 m. A metal-backed single-layer Absorber made of 20 m sendust particles absorbed more than 99% of electromagnetic wave power at frequencies above 20 GHz. Meanwhile, a composite made of 5 m particles exhibited a return loss of less than −20 dB in the frequency range of not only several GHz but also above 30 GHz. In addition, the relative complex permeability r* was shown to be controlled by adjusting the particle size of sendust, and an electromagnetic wave Absorber with a flexible design was proposed.

  • Composite electromagnetic wave Absorber made of soft magnetic material and polystyrene resin and control of permeability and permittivity
    Journal of The European Ceramic Society, 2009
    Co-Authors: K Sakai, Norizumi Asano, Yoichi Wada, Shin Yoshikado
    Abstract:

    Abstract The frequency dependences of the relative complex permeability μ r * , the relative complex permittivity e r * and the absorption characteristics for composite electromagnetic wave Absorbers made of polystyrene resin and sendust particles or permalloy particles were investigated in the frequency range from 1 to 40 GHz. The size of sendust particles was varied between approximately 5 and 20 μm and the particle size dependence of μ r * was observed. The value of μ r * was shown to be controlled by adjusting the particle size of sendust, and an electromagnetic wave Absorber with a flexible design was proposed. A metal-backed single-layer Absorber made of sendust particles or permalloy particles absorbed more than 99% of electromagnetic wave power at frequencies above 20 GHz. In addition, a composite made of 5 μm particles exhibited a return loss of less than −20 dB in the frequency range of not only several GHz but also above 30 GHz.

  • composite electromagnetic wave Absorber made of permalloy or sendust and effect of sendust particle size on absorption characteristics
    Piers Online, 2008
    Co-Authors: K Sakai, Yoichi Wada, Shin Yoshikado
    Abstract:

    The effects of the size and shape of sendust particles on the absorption characteristics of composite electromagnetic wave Absorbers made of polystyrene resin and sendust were investigated. We also investigated the difference in the absorption characteristics between permalloy and sendust. The sendust particles were granular or flakes and those of permalloy were granular. The size of sendust particles was varied in the range from approximately 5 to 20μm. A metal-backed single layer Absorber made of a composite containing small sendust particles absorbed more than 99% of electromagnetic wave power in the frequency range from 1 to 3GHz. The values of the real part μr of the relative complex permeability μ ∗ r for both magnetic materials became less than unity and had a minimum value at frequencies above 10 GHz. The composite made of small sendust particles exhibited a return loss of less than −20 dB at frequencies near 35GHz for a suitable sample thickness.

Panna Lal Singh - One of the best experts on this subject based on the ideXlab platform.

  • heat loss study of trapezoidal cavity Absorbers for linear solar concentrating collector
    Energy Conversion and Management, 2010
    Co-Authors: Panna Lal Singh, R M Sarviya, J L Bhagoria
    Abstract:

    Abstract There should be minimum heat loss from the Absorber to achieve better efficiency of the solar collector. Overall heat loss coefficients of the trapezoidal cavity Absorber with rectangular and round pipe were studied in the laboratory. Two identical rectangular pipe Absorbers (section size: 100 × 23 mm, thickness: 2.5 mm and length 2170 mm) and two round pipe Absorbers (a set of six mild steel round tubes of 16 mm diameter and 2.5 mm thickness brazed together in single layer making 100 mm width) were fabricated. A rectangular and a round pipe were painted with ordinary mat black paint (emissivity at 100 °C = 0.91) and one pipe of each type was coated with black nickel selective surface (emissivity at 100 °C = 0.17). Overall heat loss coefficient of the Absorber was studied by circulating hot oil through it at different temperatures. The heat loss coefficient was increased with the Absorber temperature. The heat loss coefficients for ordinary black coated and selective surface coated round pipe Absorbers were varied from 3.5 to 7.5 W/m 2 /°C and 2.7–5.8 W/m 2 /°C respectively. The rectangular pipe section has marginally higher heat loss coefficients as compared to round pipe Absorber. Selective surface coating on the Absorbers reduced heat loss coefficient significantly by 20–30% as compared to ordinary black coating. The double glass cover also reduced heat loss coefficient by 10–15% as compared to single glass cover. The overall heat loss coefficients were also estimated analytically by parallel plate correlation and cavity correlations. The trend of variation of estimated heat loss coefficients by both methods was similar to experimental values. However, estimated values by cavity correlation were closure and uniformly distributed at all temperature range.

  • thermal performance of linear fresnel reflecting solar concentrator with trapezoidal cavity Absorbers
    Applied Energy, 2010
    Co-Authors: Panna Lal Singh, R M Sarviya, J L Bhagoria
    Abstract:

    Thermal performance of the four identical trapezoidal cavity Absorbers for linear Fresnel reflecting solar device were studied and compared. The Absorbers were designed for operating in conjunction with a prototype Fresnel solar reflector. Rectangular and round pipe sections were used as Absorber by placing in the trapezoidal cavity. The Absorber pipes were coated with ordinary dull black board paint and black nickel selective surface. The bottom of the cavity was provided with plane glass to allow the solar radiation to be reflected from the Fresnel reflector. The other three sides of the cavity Absorber were insulated to reduce heat loss. Thermal performance of the Fresnel reflecting concentrator with each trapezoidal cavity Absorber was studied experimentally at different concentration ratio of the reflector. The study revealed that the thermal efficiency was influenced by the concentration ratio and selective surface coating on the Absorber. The thermal efficiency decreased with the increase in the concentration ratio of the Fresnel reflecting collector. The selective surface coated Absorber had a significant advantage in terms of superior thermal performance as compared to ordinary black painted Absorber. The round pipe (multi-tube) receiver had higher surface area to absorb solar energy as compared to rectangular pipe receiver. Thermal efficiency of the solar device with round pipe Absorber was found higher (up to 8%) as compared to rectangular pipe Absorber.

Charlotte Platzerbjorkman - One of the best experts on this subject based on the ideXlab platform.

  • selenium inclusion in cu 2 znsn s se 4 solar cell Absorber precursors for optimized grain growth
    IEEE Journal of Photovoltaics, 2018
    Co-Authors: Nils Ross, Sigbjorn Grini, Katharina Rudisch, Lasse Vines, Charlotte Platzerbjorkman
    Abstract:

    Cu2ZnSn(S,Se)4 precursors are fabricated by compound cosputtering from metal sulfide and selenide targets, and annealed in mixed argon, sulfur, and selenium atmosphere at temperatures between 540 and 580 $^\circ$ C and at pressures between 24 and 47 kPa. We produce solar cell devices from these Absorbers that range from 2.0% to 9.0% power conversion efficiency. We extensively characterize the morphology and elemental composition of the Absorbers, and are able to closely relate the annealing conditions, precursor sulfur–selenium content, device performance, and Absorber quality. We develop a qualitative model which relates the sulfur–selenium distribution in the precursor and the relative partial pressures of sulfur and selenium during the annealing process to the Absorber properties. We show that selenium inclusion in the precursor allows more rapid recrystallization of the Absorber at lower temperature. Alternating stacking of sulfur and selenium containing precursor material leads to differential rates of recrystallization, which allows some control over the morphology of the annealed Absorber and Zn(S,Se) secondary phase segregation in that Absorber. We further show that selenium containing precursors can be used to fabricate the superior devices relative to sulfur-only precursors, when the annealing phase space is subject to severe practical restrictions.

Richard A Soref - One of the best experts on this subject based on the ideXlab platform.

  • wideband perfect light Absorber at midwave infrared using multiplexed metal structures
    Optics Letters, 2012
    Co-Authors: Joshua R Hendrickson, Junpeng Guo, Boyang Zhang, W R Buchwald, Richard A Soref
    Abstract:

    We experimentally demonstrate a wideband near-perfect light Absorber in the midwave IR region using a multiplexed plasmonic metal structure. The wideband near-perfect light Absorber is made of two different size gold metal squares multiplexed on a thin dielectric spacing layer on top of a thick metal layer in each unit cell. We also fabricate regular nonmultiplexed structure perfect light Absorbers. The multiplexed structure IR Absorber absorbs more than 98% of the incident light over a much wider spectral band than regular nonmultiplexed structure perfect light Absorbers in the midwave IR region.

  • a wide band perfect light Absorber at mid wave infrared using multiplexed metal structures
    arXiv: Optics, 2012
    Co-Authors: Joshua R Hendrickson, Junpeng Guo, Boyang Zhang, W R Buchwald, Richard A Soref
    Abstract:

    We experimentally demonstrate a wide band near perfect light Absorber in the mid-wave infrared region using multiplexed plasmonic metal structures. The wide band near perfect light Absorber is made of two different size gold metal squares multiplexed on a thin dielectric spacing layer on the top of a thick metal layer in each unit cell. We also fabricate regular non-multiplexed structure perfect light Absorbers. The multiplexed structure IR Absorber absorbs above 98% incident light over a much wider spectral band than the regular non-multiplexed structure perfect light Absorbers in the mid-wave IR region.