Evaluating the Optical Properties of TiO<sub>2</sub>Nanofluid for a Direct Absorption Solar Collector

Said, Zafar; Sajid, M.H.; Saidur, R.; Mahdiraji, Ghafour Amouzad; Rahim, N.A.

doi:10.1080/10407782.2014.955344

Cited by 75 publications

(25 citation statements)

References 35 publications

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“…Said et al [65] analyzed the effects of size and concentration of TiO2 nanoparticles on the extinction coefficient using the Rayleigh approach. The results showed that smaller particle size (< 20 nm) has a nominal effect on the optical properties of nanofluids.…”

Section: Heat and Nanofluid Transfermentioning

confidence: 99%

Advances of Nanofluids in Solar Collectors - A Review of Numerical Studies

Menni¹,

Chamkha²,

Lorenzini³

et al. 2019

MMEP

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This paper presents a detailed review of the numerical studies carried out by various researchers in order to obtain enhanced heat transfer in free, forced, and mixed convection, under laminar, transition, and turbulent flow regimes, by using nanofluids in different solar collector geometries. Recently, nanofluids have been increasingly used in various solar collector configurations. Nano-sized metallic or non-metallic particles such as Cu, Au, Al2O3, SiO2, TiO2, CuO, etc, were used in the heat transfer fluid for various solid volume fractions. The average size of the particles was less than 100 nm. The higher conductivity of nanoparticles even at low particle concentration results in higher thermal conductivity of the base fluid and improves the thermal characteristics of the system. Nanoparticle size, type and shape are important factors for the thermal conductivity enhancement of the nanofluid with nanoparticles.

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Section: Heat and Nanofluid Transfermentioning

confidence: 99%

Advances of Nanofluids in Solar Collectors - A Review of Numerical Studies

Menni¹,

Chamkha²,

Lorenzini³

et al. 2019

MMEP

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show abstract

“…Moreover, a promising improvement was achieved within a volume fraction of 1.0%, and the nanofluid was almost opaque to light. The optical properties of a titanium dioxide nanofluid for a DASC was studied by Said et al [25]. Promising results were observed for NP volume fractions less than 0.1%.…”

Section: Introductionmentioning

confidence: 99%

“…The present model assumes independent scattering, where the scattered radiation does not depend on each other. Hence, the intensities can be added, and the extinction caused by the nanofluid could be obtained by adding the individual contributions from the NPs as well as the base fluid [14,24,25]. It can be calculated by considering the independent extinction coefficient as follows:…”

Section: Radiative Propertiesmentioning

confidence: 99%

Investigating the collector efficiency of silver nanofluids based direct absorption solar collectors

et al. 2016

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volume fraction increase and then reaches a maximum value. An optimum collector height (~ 10 mm) and particle concentration (~ 0.03%) achieving a collector efficiency of 90% of the maximum efficiency can be obtained under the conditions used in the simulation. However, the collector efficiency decreases as the irradiation time increases owing to the increased heat loss. A high solar flux is desirable to maintain a high efficiency over a wide temperature range, which is beneficial for subsequent energy utilization. The modeling results also show silver and gold nanofluids obtain higher photothermal conversion efficiencies than the titanium dioxide nanofluid because their absorption spectra are similar to the solar radiation spectrum.

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“…The literature suggests that hybrid nanofluids are promising heat transfer fluids obtained by doping two or more nanoscopic components for enhancing optical and thermal properties for use in solar collectors 46 . Further Al 2 O 3 ‐based nanofluids are key contributors and cost‐effective in enhancing the thermal conductivity, 60‐63 and TiO 2 is the promising candidate for enhancing the optical properties of nanofluids 64,65 . Fluids utilized in case of solar collectors demand better thermal and optical properties and can be best attained by the synergistic effect of Al 2 O 3 and TiO 2 nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on thermal conductivity of mono and hybrid Al ₂ O ₃ –TiO ₂ nanofluids for concentrating solar collectors

2020

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Summary Hybrid nanofluids with Therminol‐55 as base fluid and TiO2 and Al2O3 as nano additives are investigated for parabolic trough collectors. Stable mono nanofluids based on Therminol‐55 with Al2O3 and TiO2 nanoparticles, and hybrid Al2O3–TiO2 nanopowder as additives are prepared by the two‐step method. Oleic acid has been made as a surfactant. The impact of nanoparticle content and fluid temperature on thermal conductivity was studied using the transient hot‐wire technique. Thermal conductivity exhibited an increase with an increase in both temperature and nanoparticle concentration. Al2O3–TiO2 Therminol‐55 hybrid nanofluids exhibit the highest increase of 33.5% in thermal conductivity followed by 27.06% in Al2O3–Therminol‐55, and lowest rise of 21% is found in TiO2–Therminol‐55 nanofluids. Synergetic effect of Al2O3 and TiO2 nanoparticles, increased Brownian motion, and filling of vacant spaces by smaller‐sized TiO2 nanoparticles in Al2O3–TiO2 hybrid nanofluids lead to effective thermal network for enhanced thermal conductivity. Maximum thermal conductivity of 0.15 W/m‐K is observed in the case of hybrid Al2O3–TiO2 Therminol‐55 nanofluid with 0.5 wt% concentration. Augmented thermal conductivity of HNF's leads to the efficient photothermal conversion in concentrating solar collectors. Further, a correlation for thermal conductivity with variation in nanoparticle content and the fluid temperature is proposed with R2 = 0.92.

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Evaluating the Optical Properties of TiO₂Nanofluid for a Direct Absorption Solar Collector

Cited by 75 publications

References 35 publications

Advances of Nanofluids in Solar Collectors - A Review of Numerical Studies

Advances of Nanofluids in Solar Collectors - A Review of Numerical Studies

Investigating the collector efficiency of silver nanofluids based direct absorption solar collectors

Experimental study on thermal conductivity of mono and hybrid Al ₂ O ₃ –TiO ₂ nanofluids for concentrating solar collectors

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Evaluating the Optical Properties of TiO2Nanofluid for a Direct Absorption Solar Collector

Cited by 75 publications

References 35 publications

Advances of Nanofluids in Solar Collectors - A Review of Numerical Studies

Advances of Nanofluids in Solar Collectors - A Review of Numerical Studies

Investigating the collector efficiency of silver nanofluids based direct absorption solar collectors

Experimental study on thermal conductivity of mono and hybrid Al 2 O 3 –TiO 2 nanofluids for concentrating solar collectors

Contact Info

Product

Resources

About

Evaluating the Optical Properties of TiO₂Nanofluid for a Direct Absorption Solar Collector

Experimental study on thermal conductivity of mono and hybrid Al ₂ O ₃ –TiO ₂ nanofluids for concentrating solar collectors