Solar radiation absorption of nanofluids containing metallic nanoellipsoids

Rátiva, Diego; Malagón, Luis Arturo Gómez

doi:10.1016/j.solener.2015.05.048

Cited by 66 publications

(11 citation statements)

References 31 publications

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“…In the evaluation of the extinction of the incident rays, the scattering effect is ignored by assuming the small size of suspended nanoparticles, usually several tens of nanometers, as also done in other studies related to DASC with nanofluids [6,7,10,12,19,34]. In the current study, the absorption coefficient α of the blended plasmonic nanofluid is assumed to be constant in the solar spectrum for achieving broadband solar energy absorption.…”

Section: Theoretical Model Of a Direct-absorption Parabolic Trough Somentioning

confidence: 99%

Performance analysis of a direct-absorption parabolic-trough solar collector using plasmonic nanofluids

2019

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A parabolic trough solar collector is a dominant technology for high-temperature industrial applications, but efficient use of a conventional surface-based parabolic trough solar collector (SBPTSC) is limited by its high radiation loss due to the high surface temperature. Recently, direct-absorption parabolic trough solar collector (DAPTSC) using nanofluids has been proposed, and its thermal efficiency has been reported to be 5-10% higher than the conventional SBPTSC for inlet temperature up to 250 • C. However, the inner tubes of the receivers of the existing DAPTSCs are all transparent, so the sun rays entering the inner tube can only travel once through the nanofluids. As a result, the optical path length for the sun rays is limited by the inner tube size, which in turn requires high value of the absorption coefficient of nanofluids. Due to the approximately linear relation between the absorption coefficient and the particle concentration, higher absorption coefficient is likely to cause particle agglomeration, leading to detrimental effects on maintaining stable collector performance. In the current study, the transparent DAPTSC is improved by applying a reflective coating on the upper half of the inner tube outer surface, such that the optical path length is doubled compared to the transparent DAPTSC; thus, the absorption coefficient of the nanofluids can be reduced accordingly. The coated DAPTSC is found to have obvious advantage compared to the transparent DAPTSC at absorption coefficient below 0.5 cm −1 for a receiver with inner tube diameter of 7 cm. In addition, performance of the transparent DAPTSC, the coated DAPTSC and the SBPTSC with black chrome coating have been compared to explore their advantageous operation conditions, such as inner tube diameter, flow rate, and inlet temperature, with or without a glass envelope for vacuum evacuation. The findings in this study will facilitate the use of nanofluids in a parabolic trough solar collector with more stability and provide a guide for choosing suitable type of parabolic trough solar collectors for specific working conditions.

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Section: Theoretical Model Of a Direct-absorption Parabolic Trough Somentioning

confidence: 99%

Performance analysis of a direct-absorption parabolic-trough solar collector using plasmonic nanofluids

2019

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“…21 ), heat sink (Nimmagada and Venkatasubbaiah 22 ), solar collectors (Xuan et al . 23 , Rativa and Gómez-Malagón 24 ), boiling (Bhosale and Borse 25 ), micro power generation (He et al . 26 ), etc.…”

Section: Introductionmentioning

confidence: 99%

A novel hybridity model for TiO2-CuO/water hybrid nanofluid flow over a static/moving wedge or corner

Dinarvand

Rostami

Pop

2019

Sci Rep

118

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In this study, we are going to investigate semi-analytically the steady laminar incompressible two-dimensional boundary layer flow of a TiO2-CuO/water hybrid nanofluid over a static/moving wedge or corner that is called Falkner-Skan problem. A novel mass-based approach to one-phase hybrid nanofluid model that suggests both first and second nanoparticles as well as base fluid masses as the vital inputs to obtain the effective thermophysical properties of our hybrid nanofluid, has been presented. Other governing parameters are moving wedge/corner parameter (λ), Falkner-Skan power law parameter (m), shape factor parameter (n) and Prandtl number (Pr). The governing partial differential equations become dimensionless with help of similarity transformation method, so that we can solve them numerically using bvp4c built-in function by MATLAB. It is worthwhile to notice that, validation results exhibit an excellent agreement with already existing reports. Besides, it is shown that both hydrodynamic and thermal boundary layer thicknesses decrease with the second nanoparticle mass as well as Falkner-Skan power law parameter. Further, we understand our hybrid nanofluid has better thermal performance relative to its mono-nanofluid and base fluid, respectively. Moreover, a comparison between various values of nanoparticle shape factor and their effect on local heat transfer rate is presented. It is proven that the platelet shape of both particles (n1 = n2 = 5.7) leads to higher local Nusselt number in comparison with other shapes including sphere, brick and cylinder. Consequently, this algorithm can be applied to analyze the thermal performance of hybrid nanofluids in other different researches.

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“…Generally, nanofluids have distinctive physical properties to those of the base liquid. Amongst them is their large thermal conductivity [45][46][47][48] and higher values of solar intensity absorptivity [49]. The thermal and optical characteristics of nanoparticles are dependent upon various factors including their thermo-physical properties (e.g.…”

Section: Applications Of Nanoparticles In Solar Stillsmentioning

confidence: 99%

A concise review on the role of nanoparticles upon the productivity of solar desalination systems

Rashidi

Karimi

Mahian

et al. 2018

J Therm Anal Calorim

139

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In recent years, nanofluids have been widely used to improve the performance of various energy systems due to their favourable thermo-physical and optical characteristics. In particular, solar distillation systems, as an affordable and reliable technique to provide freshwater, have benefited from nanofluid technology. This article performs a review of literature on the implementation of nanofluid technology in active and passive solar distillation systems. The progress made and the existing challenges are discussed and some conclusions and suggestions are made for future research. The review indicates that the daily productivities of solar distillation systems enhance by using nanofluid and increasing the volume fraction of nanoparticles. However, long-term operational stability and life cycle assessment remain critical issues. These factors should be considered for future research in this field.

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Solar radiation absorption of nanofluids containing metallic nanoellipsoids

Cited by 66 publications

References 31 publications

Performance analysis of a direct-absorption parabolic-trough solar collector using plasmonic nanofluids

Performance analysis of a direct-absorption parabolic-trough solar collector using plasmonic nanofluids

A novel hybridity model for TiO2-CuO/water hybrid nanofluid flow over a static/moving wedge or corner

A concise review on the role of nanoparticles upon the productivity of solar desalination systems

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