Growth and characterization of spectrally selective Cr2O3/Cr/Cr2O3 multilayered solar absorber by e-beam evaporation

Khelifa, Amine; Khamlich, S.; Nuru, Z.Y.; Kotsedi, L.; Mebrahtu, A.; Balgouthi, M.; Guizani, Amenallah; Dimassi, Wissem; Mâaza, M.

doi:10.1016/j.jallcom.2017.11.036

Cited by 50 publications

(18 citation statements)

References 35 publications

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“…There are two main absorption mechanisms for the absorption of incident radiation: (a) intrinsic absorption and (b) interference-induced absorption. The intrinsic absorption is characterized by the extinction coefficient (j) of the coating, whereas, the interferenceinduced absorption depends on the refractive index (n) and thickness of the coating as well as the substrate properties [95][96][97]. To achieve high absorption of solar radiation, the solar selective coatings are constructed with various combinations of these two absorption mechanisms.…”

Section: Advances In Solar Receiversmentioning

confidence: 99%

“…In order to investigate the principle mechanism of DMD coatings, Khelifa et al [97] investigated the method of preparation as well as the structural and optical properties of a Cr 2 O 3 /Cr/Cr 2 O 3 DMD solar absorber. It consists of a thin semitransparent metal layer of chromium sandwiched between two dielectric layers of chromium oxide deposited on SS substrate.…”

Section: Advances In Solar Receiversmentioning

confidence: 99%

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Technological Advances to Maximize Solar Collector Energy Output: A Review

Salvi

Bhalla

Taylor

et al. 2018

Journal of Electronic Packaging

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Since it is highly correlated with quality of life, the demand for energy continues to increase as the global population grows and modernizes. Although there has been significant impetus to move away from reliance on fossil fuels for decades (e.g., localized pollution and climate change), solar energy has only recently taken on a non-negligible role in the global production of energy. The photovoltaics (PV) industry has many of the same electronics packaging challenges as the semiconductor industry, because in both cases, high temperatures lead to lowering of the system performance. Also, there are several technologies, which can harvest solar energy solely as heat. Advances in these technologies (e.g., solar selective coatings, design optimizations, and improvement in materials) have also kept the solar thermal market growing in recent years (albeit not nearly as rapidly as PV). This paper presents a review on how heat is managed in solar thermal and PV systems, with a focus on the recent developments for technologies, which can harvest heat to meet global energy demands. It also briefs about possible ways to resolve the challenges or difficulties existing in solar collectors like solar selectivity, thermal stability, etc. As a key enabling technology for reducing radiation heat losses in these devices, the focus of this paper is to discuss the ongoing advances in solar selective coatings and working fluids, which could potentially be used in tandem to filter out or recover the heat that is wasted from PVs. Among the reviewed solar selective coatings, recent advances in selective coating categories like dielectric-metal-dielectric (DMD), multilayered, and cermet-based coatings are considered. In addition, the effects of characteristic changes in glazing, absorber geometry, and solar tracking systems on the performance of solar collectors are also reviewed. A discussion of how these fundamental technological advances could be incorporated with PVs is included as well.

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Section: Advances In Solar Receiversmentioning

confidence: 99%

Section: Advances In Solar Receiversmentioning

confidence: 99%

Technological Advances to Maximize Solar Collector Energy Output: A Review

Salvi

Bhalla

Taylor

et al. 2018

Journal of Electronic Packaging

View full text Add to dashboard Cite

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“…To realize an SSA with an emissivity curve close to the ideal one, different designs have been analyzed by several authors in the past years [13,14]: nanomultilayer [15], ceramic and metal structures (known as cermet) [11], multilayers [16][17][18], photonic designs [19], structured graphene metamaterial [20], multi-layered cermets [10]. However, a very sharp transition was never obtained and recently Yang et al [21] studied the effect of non-ideal SSA properties on the overall performances in a Concentrated Solar Power (CSP) system: their simulated SSA has a finite constant slope in the cut-off transition (instead of the ideal step function) and a not ideal SSA emissivity.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of Selective Solar Absorber in High Vacuum Flat Solar Thermal Panels: The Role of Emissivity

Maio¹,

D’Alessandro²,

Caldarelli³

et al. 2020

Preprint

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This study refers to the optimization of a Selective Solar Absorber to improve the Sun-to-thermal conversion efficiency at mid temperatures in high vacuum flat thermal collectors. Efficiency has been evaluated by using analytical formula and a numerical thermal model. Both results have been experimentally validated using a commercial absorber in a custom experimental set-up. The optimization procedure aimed at obtaining Selective Solar Absorber is presented and discussed in the case of a metal dielectric multilayer based on Cr2O3 and Ti. The importance of adopting a real spectral emissivity curve to estimate high thermal efficiency at high temperatures in selective solar absorber is outlined. Optimized absorber multilayers can be 8% more efficient than the commercial alternative at 250 °C operating temperatures and up to 27% more efficient at 300 °C. Once the multilayer has been optimized the choice of a very low emissivity substrate such as copper allows to further improve efficiency and to reach stagnation temperature higher than 400 °C without Sun concentration.

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“…The core component in a solar thermal collector is the Selective Solar Absorber (SSA). The idea was first introduced at the end of '50, and since then, several works have been devoted to study and to optimize SSA [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The ideal SSA should efficiently absorb solar radiation (solar absorptance α=1), whereas its thermal emission should be minimal (emissivity =0).…”

Section: Introductionmentioning

confidence: 99%

“…In this work a multilayer absorber consisting of Cr 2 O 3 /Ti/Cr 2 O 3 on smooth Aluminium substrate has been numerically investigated. Multilayer absorbers allow to control thermal emission while guaranteeing high solar absorption, excellent thermal stability and their optical properties can be easily simulated [9,12,14,20,35,36]. A single SiO 2 layer has been used as antireflective coating to improve absorptance.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of Selective Solar Absorber in High Vacuum Flat Solar Thermal Panels: The Role of Emissivity and Cut-Off Wavelength

Maio¹,

D’Alessandro²,

Caldarelli³

et al. 2020

Preprint

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A multilayer structure on a metallic substrate has been optically simulated and the optimization procedure aimed at obtaining Selective Solar Absorber (SSA) is discussed. This study refers to flat high vacuum thermal collectors and the overall Sun-to-thermal conversion efficiency has been evaluated using analytical formula and numerical thermal model. Both methods are in agreement and they have been validated using experimental results on a commercial absorber. The importance of a low emittance value to obtain high thermal efficiency at high temperatures and high stagnation temperature in selective solar absorber is highlighted. Optimized absorbers can be 8% more efficient than the commercial alternative at 250 °C operating temperatures and up to 27% more efficient at 300 °C. A stagnation temperature higher than 400 °C can be reached without Sun concentration if the proper design is adopted.

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Growth and characterization of spectrally selective Cr2O3/Cr/Cr2O3 multilayered solar absorber by e-beam evaporation

Cited by 50 publications

References 35 publications

Technological Advances to Maximize Solar Collector Energy Output: A Review

Technological Advances to Maximize Solar Collector Energy Output: A Review

Efficiency of Selective Solar Absorber in High Vacuum Flat Solar Thermal Panels: The Role of Emissivity

Efficiency of Selective Solar Absorber in High Vacuum Flat Solar Thermal Panels: The Role of Emissivity and Cut-Off Wavelength

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