A review of the applications of nanofluids in solar energy
TL;DR: In this article, the authors investigated the effects of nanofluids on the performance of solar collectors and solar water heaters from the efficiency, economic and environmental considerations viewpoints, and made some suggestions to use the nanoparticles in different solar thermal systems such as photovoltaic/thermal systems, solar ponds, solar thermoelectric cells, and so on.
About: This article is published in International Journal of Heat and Mass Transfer.The article was published on 2013-02-01. It has received 1069 citations till now. The article focuses on the topics: Nanofluids in solar collectors & Solar energy.
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TL;DR: In this paper, a review summarizes recent researches on synthesis, thermophysical properties, heat transfer and pressure drop characteristics, possible applications and challenges of hybrid nanofluids, and showed that proper hybridization may make the hybrid nanoparticles very promising for heat transfer enhancement, however, lot of research works are still needed in the fields of preparation and stability, characterization and applications to overcome the challenges.
Abstract: Researches on the nanofluids have been increased very rapidly over the past decade. In spite of some inconsistency in the reported results and insufficient understanding of the mechanism of the heat transfer in nanofluids, it has been emerged as a promising heat transfer fluid. In the continuation of nanofluids research, the researchers have also tried to use hybrid nanofluid recently, which is engineered by suspending dissimilar nanoparticles either in mixture or composite form. The idea of using hybrid nanofluids is to further improvement of heat transfer and pressure drop characteristics by trade-off between advantages and disadvantages of individual suspension, attributed to good aspect ratio, better thermal network and synergistic effect of nanomaterials. This review summarizes recent researches on synthesis, thermophysical properties, heat transfer and pressure drop characteristics, possible applications and challenges of hybrid nanofluids. Review showed that proper hybridization may make the hybrid nanofluids very promising for heat transfer enhancement, however, lot of research works is still needed in the fields of preparation and stability, characterization and applications to overcome the challenges.
846 citations
Cites background from "A review of the applications of nan..."
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...Application areas are widely varied such as electronic cooling, engine cooling/vehicle thermal management, generator cooling, coolant in machining, welding, nuclear system cooling, lubrication, thermal storage, solar heating, cooling and heating in buildings, transformer cooling, biomedical, drug reduction, heat pipe, refrigeration, space, defense and ships [3,12,21,32,33,42,52,54,55,59,104]....
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Ferdowsi University of Mashhad1, King Mongkut's University of Technology Thonburi2, Xi'an Jiaotong University3, University of Monastir4, Shahid Beheshti University5, University of Rennes6, Clarkson University7, North Carolina State University8, University of Vermont9, Iran University of Science and Technology10, University of New South Wales11, Royal Society12, Quaid-i-Azam University13, King Abdulaziz University14, University of Tehran15, Babeș-Bolyai University16
TL;DR: A review of the latest developments in modeling of nanofluid flows and heat transfer with an emphasis on 3D simulations can be found in this paper, where the main models used to calculate the thermophysical properties of Nanofluids are reviewed.
659 citations
TL;DR: In this article, the authors reviewed the most important studies on the major components of central receiver solar thermal power plants including the heliostat field, the solar receiver and the power conversion system.
Abstract: The use of central receiver system (CRS) for electricity production promises to be one of the most viable options to replace fossil fuel power plants. Indeed, research and development activities on its basic subsystems have been booming rapidly since 1980s. This paper reviews the most important studies on the major components of central receiver solar thermal power plants including the heliostat field, the solar receiver and the power conversion system. After an overview of Concentrating Solar Power (CSP) technology, current status and applications of the CRSs are highlighted. Next, a detailed literature survey of existing design comprising optical, thermal and thermodynamic analysis, and techniques used to assess components have been arranged. This is followed by experimental investigations in which design concepts are established. The last section contains recent subsequent improvement of such key components as heliostat, receiver and hybrid solar gas turbine that are boosting in many R&D activities merging international collaboration during the past 30 years.
575 citations
TL;DR: In this paper, the Advanced Research Projects Agency-Energy (ARPA-Energy) gave DE-AR0000471 and DE-ARM0000181 for the first time, respectively.
Abstract: United States. Advanced Research Projects Agency-Energy (Awards DE-AR0000471 and DE-AR0000181)
483 citations
TL;DR: In this article, a review of the literature on entropy generation due to flow and heat transfer of nanofluids in different geometries and flow regimes is presented, and some suggestions for future work are presented.
416 citations
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TL;DR: In this article, the authors considered seven slip mechanisms that can produce a relative velocity between the nanoparticles and the base fluid and concluded that only Brownian diffusion and thermophoresis are important slip mechanisms in nanofluids.
Abstract: Nanofluids are engineered colloids made of a base fluid and nanoparticles (1-100 nm) Nanofluids have higher thermal conductivity' and single-phase heat transfer coefficients than their base fluids In particular the heat transfer coefficient increases appear to go beyond the mere thermal-conductivity effect, and cannot be predicted by traditional pure-fluid correlations such as Dittus-Boelter's In the nanofluid literature this behavior is generally attributed to thermal dispersion and intensified turbulence, brought about by nanoparticle motion To test the validity of this assumption, we have considered seven slip mechanisms that can produce a relative velocity between the nanoparticles and the base fluid These are inertia, Brownian diffusion, thermophoresis, diffusioplwresis, Magnus effect, fluid drainage, and gravity We concluded that, of these seven, only Brownian diffusion and thermophoresis are important slip mechanisms in nanofluids Based on this finding, we developed a two-component four-equation nonhomogeneous equilibrium model for mass, momentum, and heat transport in nanofluids A nondimensional analysis of the equations suggests that energy transfer by nanoparticle dispersion is negligible, and thus cannot explain the abnormal heat transfer coefficient increases Furthermore, a comparison of the nanoparticle and turbulent eddy time and length scales clearly indicates that the nanoparticles move homogeneously with the fluid in the presence of turbulent eddies so an effect on turbulence intensity is also doubtful Thus, we propose an alternative explanation for the abnormal heat transfer coefficient increases: the nanofluid properties may vary significantly within the boundary layer because of the effect of the temperature gradient and thermophoresis For a heated fluid, these effects can result in a significant decrease of viscosity within the boundary layer, thus leading to heat transfer enhancement A correlation structure that captures these effects is proposed
5,329 citations
TL;DR: In this article, an innovative new class of heat transfer fluids can be engineered by suspending metallic nanoparticles in conventional heat-transfer fluids, which are expected to exhibit high thermal conductivities compared to those of currently used heat transfer fluid, and they represent the best hope for enhancing heat transfer.
Abstract: Low thermal conductivity is a primary limitation in the development of energy-efficient heat transfer fluids that are required in many industrial applications. In this paper we propose that an innovative new class of heat transfer fluids can be engineered by suspending metallic nanoparticles in conventional heat transfer fluids. The resulting {open_quotes}nanofluids{close_quotes} are expected to exhibit high thermal conductivities compared to those of currently used heat transfer fluids, and they represent the best hope for enhancement of heat transfer. The results of a theoretical study of the thermal conductivity of nanofluids with copper nanophase materials are presented, the potential benefits of the fluids are estimated, and it is shown that one of the benefits of nanofluids will be dramatic reductions in heat exchanger pumping power.
4,634 citations
TL;DR: In this paper, an expression for the viscosity of solutions and suspensions of finite concentration is derived by considering the effect of the addition of one solute-molecule to an existing solution, which is considered as a continuous medium.
Abstract: An expression for the viscosity of solutions and suspensions of finite concentration is derived by considering the effect of the addition of one solute‐molecule to an existing solution, which is considered as a continuous medium.
3,724 citations
TL;DR: In this article, the physical origin of surface plasmon absorption in gold nanoparticles with emphasis on the Mie and also the Maxwell-Garnett theory is discussed. And the effects of particle size and shape on the resonance condition are reviewed.
Abstract: Driven by the search for new materials with interesting and unique properties and also by the fundamental question of how atomic and molecular physical behaviour develops with increasing size, the field of nanoparticle research has grown immensely in the last two decades. Partially for these reasons, colloidal solutions of metallic (especially silver and gold) nanoparticles have long fascinated scientists because of their very intense colours. The intense red colour of colloidal gold nanoparticles is due to their surface plasmon absorption. This article describes the physical origin of the surface plasmon absorption in gold nanoparticles with emphasis on the Mie and also the Maxwell-Garnett theory and reviews the effects of particle size and shape on the resonance condition. A better understanding of the relationship between the optical absorption spectrum (in particular, the plasmon resonance) and such particle properties as its dimensions or surrounding environment can prove fruitful for the use of the ...
2,007 citations