scholarly journals An Ultra-High Temperature Stable Solar Absorber Using the ZrC-Based Cermets

2021 ◽  
Vol 9 ◽  
Author(s):  
Jian Wang ◽  
Zuoxu Wu ◽  
Yijie Liu ◽  
Shuaihang Hou ◽  
Zhikun Ren ◽  
...  

Exploring the spectrally selective absorbers with high optical performance and excellent thermal stability is crucial to improve the conversion efficiency of solar energy to electricity in concentrated solar power (CSP) systems. However, there are limited reports on the selective solar absorbers utilized at 900oC or above. Herein, we developed a selective absorption coating based on the ultra-high temperature ceramic ZrC and the quasi-optical microcavity (QOM) optical structure, and experimentally achieved the absorber via depositing an all-ceramic multilayer films on a stainless steel substrate by magnetron sputtering. The prepared multi-layer selective absorber demonstrates an excellent high solar absorptance of ∼0.964 due to the multi absorptance mechanisms in the QOM, and a relatively low thermal emittance of ∼0.16 (82°C). Moreover, the coating can survive at 900oC in vacuum for 100 h with a superior spectral selectivity of 0.96/0.143 (82°C) upon annealing, resulting from the introduction of ultra-high temperature ceramic ZrC in the QOM structure. Under the conditions of a stable operating temperature of 900°C and a concentration ratio of 1,000 suns, the calculated ideal conversion efficiency using this absorber can reach around 68%, exceeding most solar selective absorbers in previous reports.

MRS Advances ◽  
2016 ◽  
Vol 1 (41) ◽  
pp. 2807-2813 ◽  
Author(s):  
Atasi Dan ◽  
Kamanio Chattopadhyay ◽  
Harish C. Barshilia ◽  
Bikramjit Basu

AbstractThe solar absorptance property of W/WAlN/WAlON/Al2O3-based coatings, deposited by DC/RF magnetron sputtering on stainless steel substrate was studied by measuring the reflectance spectra in the wavelength range of 250 - 2500 nm. The effect of thermal annealing on the optical properties of the solar selective absorber coatings was investigated. Annealing the coatings at 450°C for 150 hrs in air did not show any significant change in the spectral properties of the absorber coating indicating the excellent thermal stability of the coating. The W layer acts as infrared reflective layer and diffusion barrier on stainless steel substrate. The top Al2O3 layer serves as dense shield to protect the under layers from oxidation in air. In summary, the present study indicates the potential application of W/WAlN/WAlON/Al2O3-based selective coatings in high temperature photo thermal conversion systems.


Author(s):  
Andrea Ambrosini ◽  
Timothy N. Lambert ◽  
Marlene Bencomo ◽  
Aaron Hall ◽  
Kent vanEvery ◽  
...  

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 (<0.3 at receiver surface operating temperatures), be stable in air, and be low-cost and readily manufacturable. Recent efforts at Sandia National Laboratories have begun to address the issue of more efficient solar selective coatings for tower applications. This paper will present an overview of these efforts which address the development of new coatings on several fronts.


MRS Advances ◽  
2020 ◽  
Vol 5 (50) ◽  
pp. 2575-2583 ◽  
Author(s):  
Xuanjie Wang ◽  
Hengyuan Yang ◽  
Mei-Li Hsieh ◽  
James A. Bur ◽  
Shawn-Yu Lin ◽  
...  

AbstractSolar energy can alleviate our dependence on traditional energy sources like coal and petroleum. In this regard, the design and performance of solar absorbers are crucial for capturing energy from sunlight. Specifically, for applications relying on solar-thermal energy conversion, it is desirable to construct solar absorbers using scalable techniques that also allow a variation in optical properties. In this study, we demonstrate the ability to tune the spectral absorptance of nickel-infused nanoporous alumina using a scalable and inexpensive fabrication procedure. With simple variations in the geometry of the nanostructures, we enable broadband absorption with a net solar absorptance of 0.96 and thermal emittance of 0.98 and spectrally-selective absorption with a net solar absorptance of 0.83 and thermal emittance of 0.22. The simple manufacturing techniques presented in this study to generate nanoengineered surfaces can lead to further advancements in solar absorbers with well-controlled and application-specific optical properties.


MRS Advances ◽  
2020 ◽  
Vol 5 (21-22) ◽  
pp. 1133-1143 ◽  
Author(s):  
R. Akoba ◽  
G. G. Welegergs ◽  
M. Luleka ◽  
J Sackey ◽  
N Nauman ◽  
...  

ABSTRACTA novel technique providing a cost effective sustainable wet chemical etching method of synthesizing black Moly thin films rapidly has been presented. A top- down method for fabricating MoO3 has been investigated to understand the effect of chemical etchant concentration on the structural, morphological and optical properties of the thin films on Mo substrates. The XRD patterns demonstrated the formation of Tugarinovite MoO2 films on Mo substrate after annealing at 500°C in a vacuum. In this work, we developed nanostructured MoO3 on Mo substrate solar absorber, with a high solar absorptance of over 89%. These results suggest that solar absorbers made from refractory metal oxide nanostructures can be used for solar thermal applications.


2018 ◽  
Vol 15 (11) ◽  
pp. 793-802
Author(s):  
Warisa WAMAE ◽  
Tawat SURIWONG ◽  
Thotsaphon THRERUJIRAPAPONG

Three tin pigmented aluminium oxide (Sn-Al2O3)films were prepared with different tin content using an anodization process, which is applied as a selective solar absorber in a new prototype of evacuated tube collector (ETC). The morphology and distribution of elements on the coatings were characterized using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive X-ray (EDX) analyzer. The spectrally selective properties, defined as the ratio of solar absorptance (αsol) to thermal emittance (εtherm) were examined. In order to investigate the thermal performance of ETC using Sn-Al2O3 on an Al fin as a solar receiver, thermal efficiency (η) of the ETC was collected under steady-state conditions, as prescribed by ISO 9806-1 standard. The results, of the Sn-Al2O3 coatings reached a darker black colour with an increase in the colouring time. The samples were composed of different contents of Sn in the Al2O3 layer. The solar selectivity (αsol/εtherm) significantly increased with the increases in Sn content. The maximum thermal efficiency (ηmax) of the ETC under the nearly constant heat loss coefficient (UL), was obviously increased with the increasing Sn content. Therefore, the Sn-Al2O3 with different Sn contents is a good candidate for selective solar absorbers in a new prototype of ETC.


2016 ◽  
Vol 675-676 ◽  
pp. 467-472 ◽  
Author(s):  
Titiporn Chorchong ◽  
Tawat Suriwong ◽  
Sukruedee Sukchai ◽  
Thotsaphon Threrujirapapong

In present work, tin-pigmented alumina (Sn-Al2O3) solar absorber on the aluminium substrate was successfully prepared by anodic anodization and further characterized by different methods. The phase, morphology, reflectance (R) and thermal conductivity of the Sn-Al2O3 solar absorber were measured by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) equipped with energy dispersive X-ray (EDX) analyzer, and Ultraviolet-visible-near infrared spectrophotometer in the wavelength of 300-2500 nm. The solar absorptance (α) was calculated based on the relationship of the spectral reflectance, R(λ), and the solar spectral irradiance of AM 1.5, Is(λ), in the wavelength interval of 300-2500 nm. As the results, the surface color of the Sn-Al2O3 film was dark-black color. The XRD pattern of Sn-Al2O3 films was indexed as aluminium and tin phases. The chemical composition of the Sn-Al2O3 films composed of tin (Sn), aluminum (Al) and oxygen (O) elements. The average thickness of the produced films was 18.9 μm. It was found that Sn-Al2O3 films showed the low R (0.09) and high α (0.93) values for the whole wavelength 300-2500 nm, corresponding to theoretical properties of the solar absorber. Therefore, it can be concluded that the Sn-Al2O3 film on aluminium substrate can be applied to be the solar absorber in solar collector due to high α, which is similar to the commercial solar absorbers.


Author(s):  
Xing Fang ◽  
C. Y. Zhao ◽  
Hua Bao

In this paper, simple selective solar absorbers with three layers are investigated, and their selective absorptivity spectra are quite appropriate for high performance solar absorbers. The simple solar absorber contains top ultrathin tungsten (W) layer, middle silica layers and W substrate. The thickness of silica can determine the location of absorptivity peak while the thickness of top W layer affects the intensity of absorptivity. Considering the total conversion efficiency, optimized thicknesses in solar absorbers are determined by genetic algorithm. This optimized thin film solar absorber keeps high absorptivities when incident direction varies from 0 degree to 60 degree in both TE and TM polarizations. Experiments validate the effectivity of thin film solar absorbers, and the deviation from simulations comes from increscent refractive index and surface non-uniform.


2021 ◽  
Vol 9 ◽  
Author(s):  
Kuang Shi ◽  
Huaiyu Liu ◽  
Lei Wang ◽  
Yu Bie ◽  
Yue Yang

With the increasing of global energy requirements and environmental problems, the use of solar thermal energy has attracted widespread attention. The selective solar absorption coating is the most important part of a solar thermal conversion device. At present, most of the coatings work well in a vacuum at a high temperature, while not stably in the air environment. Based on the high-temperature resistant and infrared-reflective properties of ITO, a multilayer film of SiO2/Si3N4/SiO2/ITO/Cr has been designed as a selective solar absorber. The genetic algorithm is applied to optimize the material and thickness selection for each layer. The results show that the optimized multilayer film could achieve a high solar absorptance up to 90% while keeping a relatively low infrared emittance around 50% for temperature change between 600°C and 900°C. All the materials composing this film have been tested before to be chemically stable at a high temperature up to 900°C in the air environment. It is also adaptive to different incident angles from 0° to 60°. The finite-difference time-domain method was also adopted to plot the energy density distribution for different wavelengths, which provided the underlying mechanism for the selective emission spectrum. The findings in this study would provide valuable guidance to design a low-cost selective solar absorption coating without the need for vacuum generation.


Alloy Digest ◽  
1973 ◽  
Vol 22 (1) ◽  

Abstract HASTELLOY alloy S is a nickel-base high-temperature alloy having excellent thermal stability, good high-temperature mechanical properties and excellent resistance to oxidation up to 2000 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-184. Producer or source: Stellite Division, Cabot Corporation.


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