WO2016069174A1 - Stabilité thermique améliorée d'absorbeurs solaires à sélectivité spectrale à base de cermet constitué de plusieurs métaux - Google Patents

Stabilité thermique améliorée d'absorbeurs solaires à sélectivité spectrale à base de cermet constitué de plusieurs métaux Download PDF

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WO2016069174A1
WO2016069174A1 PCT/US2015/052952 US2015052952W WO2016069174A1 WO 2016069174 A1 WO2016069174 A1 WO 2016069174A1 US 2015052952 W US2015052952 W US 2015052952W WO 2016069174 A1 WO2016069174 A1 WO 2016069174A1
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layer
cermet
solar absorber
solar
contact
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PCT/US2015/052952
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English (en)
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Zhifeng Ren
Feng Cao
Daniel Kraemer
Gang Chen
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University Of Houston System
Massachusetts Institute Of Technology
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Priority to US15/520,026 priority Critical patent/US20170336102A1/en
Publication of WO2016069174A1 publication Critical patent/WO2016069174A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00—Details of absorbing elements
    • F24S70/30—Auxiliary coatings, e.g. anti-reflective coatings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00—Details of absorbing elements
    • F24S70/10—Details of absorbing elements characterised by the absorbing material
    • F24S70/12—Details of absorbing elements characterised by the absorbing material made of metallic material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00—Details of absorbing elements
    • F24S70/10—Details of absorbing elements characterised by the absorbing material
    • F24S70/16—Details of absorbing elements characterised by the absorbing material made of ceramic; made of concrete; made of natural stone
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00—Details of absorbing elements
    • F24S70/20—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption
    • F24S70/225—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption for spectrally selective absorption
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/40—Solar thermal energy, e.g. solar towers

Definitions

  • CSP Concentrated Solar Thermoelectric Power
  • S 3 TEC Solid State Solar-Thermal Energy Conversion Center
  • Solar thermal technologies such as solar hot water and concentrated solar power trough systems employ spectrally-selective solar absorbers. These solar absorbers are designed to efficiently absorb the sunlight while suppressing re-emission of infrared radiation at elevated temperatures.
  • a method of fabricating solar absorbers comprising: disposing a first layer in contact with a substrate; disposing a second layer in contact with the first layer; disposing a third layer in contact with the second layer; disposing a fourth layer in contact with the third layer; and disposing a fifth layer in contact with the fourth layer, wherein disposing the fifth layer forms a solar absorber comprising an absorbance within a first predetermined range and an emittance within a second predetermined range.
  • a solar absorber comprising: a reflector layer disposed in contact with a substrate; a first cermet layer disposed in contact with the reflector layer; a second cermet layer disposed in contact with the first cermet layer; and at least two anti-reflective coating (ARC) layers, wherein at least one ARC layer is disposed in contact with the second cermet layer.
  • ARC anti-reflective coating
  • a solar absorber comprising: a reflector layer disposed in contact with a substrate; a first cermet layer disposed in contact with the reflector layer, wherein the reflector layer comprises at least one of at least tungsten (W) or nickel (Ni).
  • FIG. 1 is a schematic of a spectrally selective solar absorber configuration according to certain embodiments of the present disclosure.
  • FIG. 2 illustrates the bidirectional reflectance spectra of solar absorbers before and after annealing that were fabricated according to certain embodiments of the present disclosure.
  • FIGS. 3A and 3B illustrate the surface roughness of a solar absorber upon annealing where the solar absorber was fabricated according to certain embodiments of the present disclosure.
  • FIGS. 4A-4D are AFM images illustrating the morphology change of a single cermet layer before and after annealing according to certain embodiments of the present disclosure.
  • FIG. 5 illustrates XRD patterns for pristine and annealed cermet coatings where the coatings were fabricated according to certain embodiments of the present disclosure.
  • FIG. 6 is a chart of Raman spectra of cermet coatings before and after annealing where the coatings were fabricated according to certain embodiments of the present disclosure.
  • FIG. 7 illustrates the spectral bidirectional reflectance response of solar absorbers that were fabricated according to certain embodiments of the present disclosure.
  • FIG. 8 illustrates XRD patterns of solar absorbers fabricated according to certain embodiments of the present disclosure.
  • FIG. 9 illustrates the experimental set up and results for steady state calorimetric measurements of samples fabricated according to certain embodiments of the present disclosure.
  • FIG. 10 illustrates the spectral properties of a plurality of solar absorbers that were fabricated according to embodiments of the present disclosure.
  • cermets are composite materials comprising metallic and ceramic materials that may therefore comprise desirable properties of both ceramics and metals.
  • cermets may be resistant (to loss of properties and deformation) to high temperatures like a ceramic, and may be able to undergo plastic deformation like metallic materials.
  • Cermets may be used in both electronic and mechanical applications including in solar applications and for cutting and machining tools that may also experience high temperature.
  • Reflector layers provide solar reflectance by reflecting wavelengths in various wavelength ranges, including the visible, infrared, and ultraviolet ranges, in order to reduce the heat transferred to the surface of an apparatus employing the reflector layer.
  • infrared reflector layers may be employed in solar absorbers.
  • Wavelength ranges may comprise infrared wavelengths above 700 nm (10 ⁇ 9 m) to about 1 mm, visible wavelengths may range from about 400 nm to about 700 nm, ultraviolet light wavelengths may range from less than 400 nm (e.g., shorter wavelengths than visible light) to about 10 nm, x-rays may range from less than about 10 nm (e.g., shorter than ultraviolet light) to about 10 pm (picometers, 10 "12 m), and gamma rays may be less than about 10 pm, that is, shorter than x- ray wavelengths.
  • the emittance (emissivity) of a surface may be considered because a low emittance may indicate that the solar absorber wastes less energy through emitting thermal radiation than materials with a high emittance.
  • the same principle may apply, for example, in insulation applications where it may be desirable for a window to retain heat using a coating or a film.
  • an operating temperature where selective solar absorbers may be desired is from about 500 to about 600 °C.
  • Nickel and tungsten were employed in certain embodiments for the infrared reflector layer in selective thermal absorbers discussed herein, the results of those experiments are discussed herein, including one in which a stable solar absorptance of about 0.90 and total hemispherical emittance of 0.15 at 500 °C was obtained using tungsten as the infrared reflector layer. While the infrared reflector layer may be referred to in some embodiments as "a layer,” the infrared reflector layer may be a plurality of individual (separate) layers which may be of the same or differing layer types and/or varying thicknesses, or combinations or the same type of material and different types of material with the same or varying thicknesses depending upon the embodiment.
  • a spectrally selective solar absorber comprises a substrate (stainless steel, tantalum, titanium, copper, aluminum, nickel, silicon, quartz, and combinations thereof), an infrared reflector layer or bonding layer (tungsten, tantalum, titanium, nickel, silver, gold, aluminum, and combinations thereof), a first and a second cermet layer which may comprise multi-metal nanoparticles in dielectric matrix and two anti- reflection coatings.
  • substrate stainless steel, tantalum, titanium, copper, aluminum, nickel, silicon, quartz, and combinations thereof
  • an infrared reflector layer or bonding layer tungsten, tantalum, titanium, nickel, silver, gold, aluminum, and combinations thereof
  • first and a second cermet layer which may comprise multi-metal nanoparticles in dielectric matrix and two anti- reflection coatings.
  • selective may be used to describe the manner in which the solar absorber is fabricated so that the solar absorber provides an absorbance within a first predetermined wavelength range and an emittance within a second predetermined wavelength range
  • a "cermet layer,” s a combination of two or more metals and a ceramic, and in some embodiments, a combination of at least two layers cermetl ("CI”) and cermet 2 ("C2") may be employed in a solar absorber, where each of CI and CI comprises a combination of any two or more metals, including but not limited to Nickel (Ni), Cobalt (Co), Iron (Fe), Tungsten (W), Tantalum (Ta), Titanium (Ti), Molybdenum (Mo), Chromium (Cr), Vanadium (V), Niobium (Nb), Zirconium (Zr), and at least one of AI2O 3 , S1O2, ⁇ (3 ⁇ 4, Ta 2 05, A1N, or other dielectric materials as appropriate for the end application's desired absorbance and emittance ranges.
  • CI cermetl
  • C2 cermet 2
  • ARC anti-reflection coatings
  • MgO MgO
  • T1O2 V2O5
  • Ta 2 05 Zr02
  • S1O2 S1O2
  • the stable infrared reflector layer suppresses the diffusion of the substrate elements into the cermet layer and results in enhanced thermal stability of the solar absorber at elevated temperature.
  • the metal infrared reflector layer also improves to some extent the spectral selectivity of the solar absorber due to its low infrared emittance.
  • Sunlight may be converted into a useful terrestrial heat source by employing sunlight absorbing surfaces in the form of solar absorbers.
  • Solar absorbers may be employed in solar thermal systems such as solar hot water systems and concentrated solar power (CSP) trough systems, as well as in emerging technologies such as solar thermoelectric, solar thermo- photovoltaic, and solar thermionic generators.
  • the solar thermal receiver efficiency may depend on the optical properties of the solar absorber.
  • the solar absorbers discussed herein may be employed in processes, methods, and products to convert received wavelengths into energy sources.
  • a spectrally-selective solar absorber (“solar absorber”) and methods of fabricating the solar absorber comprising a layer disposed between a substrate and an absorber coating that demonstrates a long-term stability at high temperatures (T > 400 °C) as well as a stable solar absorptance of about 0.90 and a hemispherical emittance of 0.15.
  • a “spectrally selective" solar absorber may be defined by the range of wavelengths it is designed to reflect and/or absorb.
  • cermet-based coatings may be employed and comprise ceramic metallic composites which may be good candidates for inclusion in the solar absorber due to their high solar absorptance, low emittance, and good thermal stability. These desirable properties may be attributed to the high temperature stable ceramic host.
  • Cermet-based spectrally selective solar absorbers may present and be employed as single, double, and triple cermet layers. The thin cermet layer is typically in contact with a metallic surface for high solar absorptance that is transparent to IR radiation. The absorption of solar radiation in the cermet layer may be due to interbank transitions in the metal and small particle plasmonic resonances.
  • a "graded metal volume fraction" is the term used herein to describe a combination of two or more cermet layers comprising different metal volume fractions (weight of metallic/(weight of metallic + ceramic combined)).
  • the graded metal volume fraction between and within the cermet layers gives it a gradual increase in the refractive index from surface to the substrate, which reduces reflection compared with single cermet layer absorbers that often use black metals such as black chrome, black nickel, or black tungsten as their metal fillers.
  • Solar absorbers fabricated according to embodiments of the present disclosure that comprise cermet multilayers (CI and C2 in this example) with different metal volume fractions introduces a stepwise change in the refractive index that may result in a low reflection of visible light due to interference effects.
  • cermet-based solar absorbers have a tunable parameter space (range) based upon their constituents, coating thicknesses, particle concentration, size, shape, and orientation to optimize their spectral selectivity.
  • host materials such as AI2O3, AIN, and SiCte with metallic filler atoms such as Ni, Co, Ti, Mo, W, Pt, Stainless steel (SS), Cu, Ag, Au have been investigated in terms of their respective effectiveness for the optical performance and thermal stability of the cermet surfaces.
  • These combinations of host materials have ceramic host materials in common that possess high temperature stability, and are therefore complimentary.
  • the metal filler atoms may be chosen for their high melting point and their resistance to both nitriding and oxidation, in order to enhance and ensure thermal stability.
  • the cermet layers may be deposited on metal substrates such as polished aluminum or copper due to their low IR emittance and high thermal conductivity.
  • a diffusion barrier between the substrate and the cermet layer was introduced with a spontaneously formed Fe203 layer by annealing the stainless steel substrate at 500 °C in air.
  • the surface roughness of the substrate changes when forming an Fe203 layer, which eventually affects the surface roughness of solar absorber and then increases the emittance.
  • the Fe203 layer on the back side of the stainless steel may introduce another thermal resistance layer in a solar absorber, which will decrease the heat transport efficiency from the absorber to the thermal system. Surface smoothness may be a desirable property in solar absorbers, so the impact of annealing was evaluated and is discussed herein.
  • the embodiments herein discuss depositing, for example, a nickel (Ni) or tungsten (W) layer that may be referred to as an inter-reflector (IR) layer onto a mechanically polished substrate that may comprise stainless steel. Depending upon the embodiment and the substrate material employed, the substrate may not be polished.
  • This IR layer may act note only to bond the substrate to other layers but also as a diffusion barrier and as a low IR emittance coating to improve spectral selectivity.
  • the performance of the metal IR reflector layer with a double-layer cermet structure and two antireflection coatings (ARCs) is discussed herein.
  • the cermet layers based on an AI2O3 ceramic host material may be filled with high temperature stable Ni-W alloy prepared by co-sputtering. Therefore, the cermet layers may each comprise not only the metal volume fraction in each cermet layer but also the volume fraction of the individual constituent which may be adjusted to tailor the optical properties of a solar absorber depending upon the end application, subsequent processing, or customer specifications.
  • a plurality of individual layers of the solar absorbers were deposited using a magnetron sputtering technique.
  • the spectral bidirectional reflectance responses of the fabricated solar absorbers were measured at room temperature before and after annealing at 600°C for 7 days.
  • the solar absorptance and total hemispherical emittance were measured at elevated temperatures of up to 500°C.
  • the spectrally-selective solar absorbers may be deposited in contact with a substrate, for example, a mechanically polished stainless steel substrate.
  • the deposition may be performed using a commercial magnetron sputtering equipment (AJA international, Inc.).
  • AJA international, Inc. the materials may be simultaneously deposited on Si wafer substrates partly covered by a mask.
  • the chamber Prior to the deposition process, the chamber may be evacuated to lower than 4x10-7 Torr.
  • the deposition targets are high purity nickel (99.999%, 2" Dia.), tungsten (99.95%, 3" Dia.), AI2O3 (99.98%, 2" Dia.), and S1O2 (99.995%, 3" Dia.).
  • the DC power is supplied to the metal targets (Ni, W) to deposit the metal layer and for the metal particle.
  • the dielectric layer is deposited by RF magnetron sputtering. Co-sputtering may be employed to deposit more or one dielectric layers, such as the CI and C2 layers.
  • the metal fill fractions of the cermet layers may be controlled by independent input power control to the corresponding targets.
  • the complete deposition process may be performed in an argon plasma environment at a pressure of 3 mTorr. The detailed preparation parameters are summarized in Table 1 herein.
  • the solar absorbers fabricated according to embodiments of the present disclosure are characterized in terms of their phase, morphology, and optical properties both before and after annealing the samples at 600 °C for 7 days at a vacuum pressure of about 5xl0 ⁇ 3 Torr using a tubular furnace.
  • Raman scattering spectra measurements were carried out on a T64000 Raman system (Horiba Jobin Yvon) at room temperature.
  • the excitation source is the 514 nm laser line of an air cooled Ar-ion laser.
  • the thickness of the cermet films were measured with an Alpha-step 200 Profilometer (Tencor).
  • the growth rates of metal and dielectric layers comprising the cermet layers (films) were measured by a quartz crystal monitor equipped in the sputtering system.
  • the morphology and roughness of the films were measured with a Veeco Dimensions 3000 Atomic Force Microscope (AFM).
  • AFM Atomic Force Microscope
  • the spectral bidirectional reflectance was measured at room temperature with a Spectrophotometer by Varian (Cary 500i, angle of incidence 8°, absolute spectral reflectance accessory) covering the wavelength range of 0.3 - 1.8 ⁇ , and with an FT-IR Spectrometer by Thermo Scientific (Nicolet 6700, angle of incidence 12o) covering the wavelength range of 1.8 - 20 ⁇ .
  • the latter (relative measurement) requires a reference with known spectral reflectance which is chosen to be a specular gold mirror (Thorlabs).
  • FIG. 1 is a schematic of a spectrally selective solar absorber configuration according to certain embodiments of the present disclosure. It is to be appreciated that, while different patterns are used to distinguish the layers, these indications are not necessarily indicative of differences in the layers that are visible to the naked eye, and it is also to be understood that the relative thickness of layers may vary between embodiments.
  • the spectrally selective solar absorbers fabricated according to certain embodiments of the present disclosure for mid- and high-temperature applications are based on a double cermet layer configuration with two ARC layers and a metal layer with high IR reflectance as diffusion barrier.
  • the two ARC layers ARC1 and ARC2 may also be AI2O3 and SiC thin films, respectively.
  • the ARCl layer may comprise MgO, T1O2, V2O 3 , ZrO, or combinations thereof.
  • the solar absorber multilayer structures were fabricated according to certain embodiments of the present disclosure with tungsten, optically thick nickel, or very thin nickel layer as and IR reflector or bonding layer. The detailed parameters are summarized in Table 1.
  • the substrate may comprise a metal layer, for example, nickel having a DC power density of 12.3 W/cm 2 or tungsten having a DC power density of 2.2 W/cm 2 for tungsten.
  • the CI layer may comprise W+N1+AI2O3 with a DC power density of 0.33 W/cm 2 for tungsten and 0.99 W/cm 2 for nickel, and a RF power density of 9.9 W/cm 2 for AI2O3.
  • the cermet2 layer may comprise W+ +AI2O3 with a DC power density of 0.26 W/cm 2 for tungsten, and 0.74 W/cm 2 for nickel, and a RF power density of 9.9 W/cm 2 for AI2O3.
  • the ARCl layer may comprise AI2O3 with a RF power density of 9.9 W/cm 2 and the ARC2 layer may comprise SiCte with a RF power density of 4.4 W/cm 2 .
  • the multilayer stack that makes up the spectrally selective solar absorbers fabricated according to certain embodiments of the present disclosure may comprise one bonding or IR reflector layer, double cermet absorption layers and double ARC layers which further reduce reflection in the visible range.
  • multiple IR-reflector layers of the same or differing compositions and/or concentrations (metal fractions) may be used in different arrangements in a solar absorber.
  • the use of mechanically polished stainless steel as the substrate may provide high temperature stability and may be cost-effective, which can promote large scale deployment as a potential solar absorber candidate in high temperature solar receivers.
  • FIG. 2 illustrates the bidirectional reflectance spectra of the pristine (where "pristine” is the term used to describe a condition before annealing) and annealed solar absorbers fabricated according to certain embodiments of the present disclosure.
  • the reflectance of the pristine sample is close to zero in the visible range, which is expected for a double-cermet- absorption-layer combined with a double- ARC-layer due to the intrinsic absorption of the double-cermet layer and the reflectance reducing interference effects.
  • the sharp transition wavelength range from low reflectance to high reflectance appears to be from about 1 to about 3 ⁇ , which can result in promising spectral selectivity even at high temperatures.
  • the degraded optical properties of the solar absorber upon annealing at 600 °C for 7 days show a detrimental effect on spectral selectivity.
  • the spectral reflectance below aboutl . l ⁇ increases while it decreases above about 1.1 ⁇ which results in a broadening of the transition wavelength range and ultimately decreases the solar absorptance and increases the IR emittance.
  • FIGS. 3A and 3B illustrate the surface roughness of the absorber subsequent to annealing. No significant surface roughness change upon sample annealing is observed, indicating that the annealing process does not significantly (e.g., to where it would be noticeable or negatively impact functionality) degrade the surface roughness.
  • FIG. 3 A is an atomic force microscopy ("AFM") image of an S-SS solar absorber with a lOnm thick nickel layer before annealing
  • FIG. 3B is an AFM image of the S-SS solar absorber the lOnm thick nickel layer after annealing at about 600°C for 7 days.
  • the sample retains the groove structure created by the mechanical polishing process applied to the stainless steel substrate.
  • the root mean square roughness (Rq) of the sample before and after annealing is calculated to be 6 - 8 nm using a NanoScope Analysis software.
  • FIGS. 4A-4D are AFM images illustrating the morphology change of a single cermet layer before and after annealing.
  • FIGS. 4A-4D are AFM images of the morphology changes of a single cermet layer deposited on a mechanically polished stainless steel substrate coated with a lOnm Ni layer without any ARC layer after annealing at 600°C for 7 days.
  • FIG. 4A illustrates the morphology of a cermet 1 layer with a high metal volume fraction in AI2O 3 before annealing and
  • FIG. 4B illustrates the morphology of the same sample after annealing.
  • a "high metal volume fraction” refers to a metal volume fraction above about 62% and a "low metal volume fraction” refers to a metal volume fraction below about 56%.
  • FIG. 4C illustrates the morphology of a cermet2 layer with a low metal volume fraction in AI2O 3 before annealing and FIG. 4D illustrates the morphology of the same sample after annealing.
  • two cermet samples were fabricated without being disposed in contact with anti-reflective coating ("ARC") layers, and were evaluated in terms of their phases and morphology before (“pristine") and after annealing.
  • the multilayer stacks deposited onto the stainless steel substrates consist of a 10 nm nickel bonding layer and a single cermet layer with the only difference between the two samples being the metal particle concentration in the cermet layers and their respective thicknesses (CI and C2 as detailed in Table 1). Both samples CI (FIG. 4B) and C2 (FIG. 4D) show significant changes in their film morphology upon annealing.
  • the CI and C2 samples start out with a groove surface structure; however, the annealing process leads to a rapid growth of the Ni-W alloy within the cermet layer from diameters of about 80 nm to about 300 nm or, in some embodiments, about 400 nm. And the roughness increases from about 6 - 8 nm to about 47 -50 nm.
  • the difference in the metal volume fraction and layer thickness between sample CI and C2 does not affect the particle growth and roughness change.
  • the unchanged roughness of the previous sample (S-SS) with double ARC and much thinner double-cermet layer may indicate that the ARC layers suppress the particle growth within the cermet or the particle growth is much less pronounced in significantly thinner cermet layers.
  • FIG. 5 illustrates XRD patterns for pristine and annealed cermet coatings.
  • FIG. 5 illustrates the phase analysis before and after annealing for cermet coatings with lOnm nickel layers disposed on stainless steel for both cermet 1 and cermet2 as noted, this phase analysis was conducted using X-ray diffraction and shows the sharp peaks for the stainless steel substrate and the Ni-W alloy in the single-cermet layers. No diffraction peaks are observed for the dielectric AI2O3 even after annealing at 600 °C for 7 days due to its stable amorphous nature. However, X-ray diffraction spectra show an additional monoclinic FeW0 4 phase after sample annealing. Iron atoms diffuse at high temperatures from the stainless steel substrate into the cermet layer and may react with tungsten and residual oxygen to form the observed FeW04 phase.
  • FIG. 6 is a chart of Raman spectra of pristine and annealed cermet coatings.
  • FIG. 6 illustrates Raman measurements showing two distinct peaks located at 882 cm “1 and 691 cm “1 for the annealed samples which can be traced back to A g modes of FeW0 4 .
  • the solar absorber with thin nickel layer (S-SS) after annealing displays a very low reflectance in mid-IR range compared to that before annealing as shown in FIG. 2, which may indicate a destruction of IR reflector and a formation of nonmetallic phase between substrate and coatings.
  • the degradation of the optical properties for the solar absorber sample (S-SS) may be the formation of FeW0 4 phase in the cermet layers at high temperature.
  • FIG. 7 illustrates the spectral bidirectional reflectance response of solar absorbers fabricated according to certain embodiments of the present disclosure.
  • the solar absorber samples (indicated by S-Ni/SS and S-W/SS in Table 1) were fabricated with 300 nm thick metal layers as the diffusion barrier between the stainless steel substrate and the double cermet layer. Nickel and tungsten were employed as indicated as the diffusion barrier metals due to their high melting point and low IR emittance which improves the spectral selectivity of the solar absorber compared to the previous sample S-SS with a very thin nickel layer. Both thick metal layers in the samples S-Ni/SS and S-W/SS significantly increased the spectral reflectance in the mid-IR range without altering the spectral response below 2.5 ⁇ .
  • FIG. 8 illustrates XRD patterns of solar absorbers fabricated according to certain embodiments of the present disclosure.
  • FIG. 8 illustrates that the sample with the thick nickel layer (S-Ni/SS) shows two nickel peaks which disappear after sample annealing, indicating that the nickel reacts with iron atoms from the SS substrate.
  • the sample with a thick tungsten layer (S-W/SS) did not appear to be affected by the sample annealing, thus demonstrating a stable tungsten layer which prevents the iron diffusion.
  • FIG. 9 illustrates the experimental set up and results for steady state calorimetric measurements of samples fabricated according to certain embodiments of the present disclosure.
  • FIG. 9 illustrates both the solar absorptance and total hemispherical emittance of a fabricated solar absorber (S-W/SS) was directly measured at elevated temperatures (up to 500 °C) using simple steady state calorimetric methods. Samples were attached to a heater assembly and suspended in a vacuum chamber. The electrical heater power input employed was directly related to the radiation heat loss from the sample surface. Thus, the total hemispherical emittance can be calculated with the electrical heater power inputs and the measured sample and surrounding temperatures. The solar absorptance was measured at elevated temperatures using a solar simulator.
  • the sample/heater assembly is suspended in the vacuum chamber facing a viewport allowing the solar simulator beam to irradiate the sample surface.
  • the solar absorptance can be obtained by varying the incident radiation power onto the sample and measuring the corresponding electric heater power adjustments to maintain the sample surface at a constant temperature.
  • the near normal solar absorptance and total bidirectional emittance are calculated from the spectral reflectance data, indicating that the developed spectrally selective solar absorber with tungsten infrared reflector layer can be a good candidate for high temperature solar thermal applications (See Table 2 below).
  • the near-normal solar absorptance (divergence half angle of about 15°) is close to independent of temperature with a value of about 0.9 which is in good agreement with the calculated solar absorptance from the spectral data. It has been theoretically shown that cermet-based solar absorbers exhibit a solar absorptance with only weak angle dependence. Thus, only little deviation from here demonstrated solar absorptance should be expected even for concentrated solar power applications with a large range of incident angles. However, future research efforts could experimentally investigate the angle dependence of the solar absorptance to quantify the effect.
  • the total hemispherical emittance shows the typical temperature dependence of a spectrally selective solar absorber with approximately 0.09 at 100 °C and 0.15 at 500 °C.
  • FIG. 10 illustrates the spectral properties of a plurality of solar absorbers fabricated according to embodiments of the present disclosure.
  • the tungsten metal layer thickness may be optimized to keep the production cost minimal without losing the low emittance and long term thermal stability of the solar absorber.
  • a plurality of solar absorbers with tungsten layer thicknesses of 10, 50, 100, and 200 nm were fabricated as indicated in Table 1 and their spectral properties were compared before and after the annealing at 600 °C for 7 days.
  • the curves in FIG. 10 of wavelength v. % reflectance are in the following order, and the corresponding compositions/configurations are listed in order below in Table 3, which comprises the same values for each composition/configuration as Table 1.
  • the tungsten layer thickness only affects the spectral reflectance at wavelength larger about 2 ⁇ .
  • the annealing process alters the spectral response in the complete wavelength range with the largest effect at wavelengths longer than about 1.2 ⁇ .
  • the spectral reflectance increases and the thermal stability improves with increasing tungsten layer thickness.
  • a tungsten layer thickness of 100 nm is sufficient to provide good (commercially scalable and usable) thermal stability and to act as a low emittance coating on stainless steel at high temperatures.
  • the spectrally selective solar absorbers fabricated according to certain embodiments of the present disclosure may be based on double cermet layers (W- -AI2O3 cermet) with double antireflection layers on a mechanically polished stainless substrate fabricated according to embodiments of the present disclosure.
  • a 100 nm thick tungsten layer may be employed to suppress the degradation of the optical properties at high temperatures and to lower the emittance relative to the stainless steel substrate, which improves the spectral selectivity of the solar absorber, for example, in applications where Ni may not be as effective an Fe-diffusion barrier and IR reflector.
  • a solar absorber was fabricated with a solar absorptance of about 0.9 and total hemispherical emittance of about 0.15 at an operating temperature of 500 °C.
  • this layer may comprise Tantalum (Ta), Titanium (Ti), Molybdenum (Mo), Chromium (Cr), Vanadium (V), Niobium (Nb), Zirconium (Zr), or combinations thereof.
  • R R i+k*(R u -Ri), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, 50 percent, 51 percent, 52 percent, 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent.
  • any numerical range defined by two R numbers as defined in the above is also specifically disclosed. .

Abstract

Cette invention concerne un absorbeur solaire à sélectivité spectrale, comprenant un substrat, deux couches de cermet comprenant des nanoparticules constituées de plusieurs métaux intégrées dans une matrice diélectrique et de doubles couches antireflet déposée sur les couches de cermet. L'invention concerne en outre une couche de réflecteur infrarouge à base de tungstène ou de titane ou de tantale supprimant la diffusion d'éléments du substrat ainsi que des nanoparticules constituées de plusieurs métaux dans le cermet.
PCT/US2015/052952 2014-10-29 2015-09-29 Stabilité thermique améliorée d'absorbeurs solaires à sélectivité spectrale à base de cermet constitué de plusieurs métaux WO2016069174A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107482994A (zh) * 2017-08-22 2017-12-15 郑义 一种用于热光伏系统的选择性热发射器
CN109631370A (zh) * 2018-12-10 2019-04-16 郴州市泰益表面涂层技术有限公司 中高温太阳能吸收涂层及其制备方法
CN109883073A (zh) * 2019-03-13 2019-06-14 哈尔滨工业大学（深圳） 一种高温稳定的准光学微腔结构太阳光谱选择性吸收涂层及其制备方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10533777B2 (en) * 2015-06-19 2020-01-14 University Of Houston System Selective solar absorbers with tuned oxygen deficiency and methods of fabrication thereof
CN110895058A (zh) * 2018-09-13 2020-03-20 康楚钒 一种新型高温太阳能选择性吸收涂层
WO2021161259A1 (fr) * 2020-02-13 2021-08-19 Khalifa University of Science and Technology Absorbeur solaire nanocomposite à nanoparticules métalliques encapsulées

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050134959A1 (en) * 2003-05-28 2005-06-23 Deron Simpson System and method for filtering electromagnetic transmissions
US20100313875A1 (en) * 2007-10-18 2010-12-16 Kennedy Cheryl E High temperature solar selective coatings
US20110249326A1 (en) * 2008-10-20 2011-10-13 Abengoa Solar New Technologies, S.A. Selective solar absorbent coating and manufacturing method
US8368992B2 (en) * 2006-03-03 2013-02-05 Gentex Corporation Electro-optical element including IMI coatings
EP2757176A1 (fr) * 2013-01-16 2014-07-23 Fondazione Bruno Kessler Revêtement multicouche à haute absorption de l'énergie solaire et faible émissivité thermique, composite cermet associé, leur utilisation et procédés pour leur fabrication

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AUPN364195A0 (en) * 1995-06-19 1995-07-13 University Of Sydney, The Solar selective surface coating
US6234166B1 (en) * 1999-06-30 2001-05-22 Acktar Ltd. Absorber-reflector for solar heating
ITRM20110308A1 (it) * 2011-06-15 2012-12-16 Gia E Lo Sviluppo Economico Sostenibile Enea Assorbitore solare selettivo a base di materiali cermet del tipo doppio nitruro, e relativo procedimento di fabbricazione
CN102620456B (zh) * 2012-04-06 2013-10-09 中国科学院宁波材料技术与工程研究所 一种中低温太阳能选择吸收薄膜及其制备方法
JP6224345B2 (ja) * 2012-05-01 2017-11-01 デクセリアルズ株式会社 熱吸収材及びその製造方法
US10371416B2 (en) * 2012-05-04 2019-08-06 The Regents Of The University Of California Spectrally selective coatings for optical surfaces
US20140261390A1 (en) * 2013-03-13 2014-09-18 Brightsource Industries (Israel) Ltd. High temperature radiation-selective coating and related apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050134959A1 (en) * 2003-05-28 2005-06-23 Deron Simpson System and method for filtering electromagnetic transmissions
US8368992B2 (en) * 2006-03-03 2013-02-05 Gentex Corporation Electro-optical element including IMI coatings
US20100313875A1 (en) * 2007-10-18 2010-12-16 Kennedy Cheryl E High temperature solar selective coatings
US20110249326A1 (en) * 2008-10-20 2011-10-13 Abengoa Solar New Technologies, S.A. Selective solar absorbent coating and manufacturing method
EP2757176A1 (fr) * 2013-01-16 2014-07-23 Fondazione Bruno Kessler Revêtement multicouche à haute absorption de l'énergie solaire et faible émissivité thermique, composite cermet associé, leur utilisation et procédés pour leur fabrication

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107482994A (zh) * 2017-08-22 2017-12-15 郑义 一种用于热光伏系统的选择性热发射器
CN109631370A (zh) * 2018-12-10 2019-04-16 郴州市泰益表面涂层技术有限公司 中高温太阳能吸收涂层及其制备方法
CN109883073A (zh) * 2019-03-13 2019-06-14 哈尔滨工业大学（深圳） 一种高温稳定的准光学微腔结构太阳光谱选择性吸收涂层及其制备方法

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