Experimental investigation of a silver nanoparticle-based direct absorption solar thermal system

Filho, Ênio Pedone Bandarra; Mendoza, Oscar Saúl Hernández; Beicker, Carolina Lau Lins; Menezes, Adonis; Wen, Dongsheng

doi:10.1016/j.enconman.2014.04.009

Cited by 177 publications

(44 citation statements)

References 24 publications

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“…SAR (Fig. 7) decreases with the increase of the nanoparticle concentration, which is consistent with those from previous studies under non-focused solar radiation [34,35]. An impressive high value of 50 kW/g for gold nanoparticles with a concentration of 1.02 ppm is achieved under 220 Suns solar radiation, which suggests that the absorbed solar energy by one gram of gold nanoparticles in only 3 seconds is more than the released thermal energy of 10 L hydrogen combustion under standard temperature and pressure conditions (i.e., T= 273 K and P=1 atm) [36].…”

Section: Photothermal Conversion Characteristicssupporting

confidence: 81%

Steam generation in a nanoparticle-based solar receiver

et al. 2016

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, Steam generation in a nanoparticle-based solar receiver, Nano Energy, http://dx.doi.org/10. 1016/j.nanoen.2016.08.011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Steam production is essential for a wide range of applications, and currently there is still strong debate if steam could be generated on top of heated nanoparticles in a solar receiver. We performed steam generation experiments for different concentrations of gold nanoparticles dispersions in a cylindrical receiver under focused natural sunlight of 220 Suns. Combined with mathematical modelling, it is found that steam generation is mainly caused by localized boiling and vaporization in the superheated region due to highly non-uniform temperature and radiation energy distribution, albeit the bulk fluid is still subcooled. Such a phenomenon can be well explained by the classical heat transfer theory, and the hypothesized 'nanobubble', i.e., steam produced around the heated nanoparticles, is unlikely to occur under normal solar concentrations.In the future solar receiver design, more solar energy should be focused and trapped at the superheated region while minimizing the temperature rise of the bulk fluid. Graphical abstract

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Section: Photothermal Conversion Characteristicssupporting

confidence: 81%

Steam generation in a nanoparticle-based solar receiver

et al. 2016

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“…Filho et al [139] investigated the effect of Ag/water nanofluid in direct absorption solar collectors. Stable formulation of Ag/water was prepared by high pressure homogenizer, Fig.…”

Section: Belowmentioning

confidence: 99%

Progress of nanofluid application in solar collectors: A review

Verma

Tiwari

2015

Energy Conversion and Management

279

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“…A variety of direct absorption nanoparticles materials had have been analyzed in terms of the enhancement in the photothermal performance, including Ag [27][28][29], Au [30][31][32], CNT (carbon nanotubes) [33][34][35], Cu [36], Al 2 O 3 [37,38], graphite [17], graphene [22], and TiO 2 [39]. In addition to the volumetric heating, direct vapor generation due to localized heating of the As far as the steam generation mechanism is concerned, for nanobubbles to be produced around heated nanoparticles, it has been shown analytically that a minimum radiation flux of 3×10 8 W/m 2 is required to produce nanobubbles on heated nanoparticles [46,49,50], which can may only be reached developed by powerful laser beams.…”

Section: Introductionmentioning

confidence: 99%

Volumetric solar heating and steam generation via gold nanofluids

et al. 2017

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Volumetric solar absorption using nanofluids can minimize the thermal loss by trapping the light inside the fluid volume. A strong surface boiling with the underneath fluid still subcooled could have many interesting applications, whose mechanism is however still under strong debate. This work advanced our understanding on volumetric fluid heating by performing a novel experiment under a unique uniform solar heating setup at 280 Suns, with a particular focus on the steam production phenomenon using gold nanofluids. To take the temperature distribution into account, a new integration method was used to calculate the sensible heating contribution. The results showed that the photothermal conversion efficiency was enhanced significantly by gold nanofluids. A three-stage heating scenario was identified and during the first stage most of the energy was absorbed by the surface fluid, resulting in rapid vapor generation with the underneath fluid still subcooled. The condensed vapor analysis showed no nanoparticle escaping even under vigorous boiling conditions. Such results reveal that nanoparticle enabled volumetric solar heating could have many promising applications including clean water production in arid areas where abundant solar energy is available. highlights  Novel experiment was performed for nanofluids at a focused solar flux of 280 Suns. Strong surface evaporation was enabled while the bulk fluid was still subcooled  A new integration method was used to calculate photothermal conversion efficiency  Gold nanofluid (0.04w%) increased photothermal conversion efficiency by 95%. The authors are grateful for all the constructive comments from the reviewer and the Editor. Most of the comments were concerned on the presentation of the work. We have addressed all these concerns in the revised version, and a point-by-point reply is supplied below Reviewer #1:The authors of the present work experimentally investigated the surface boiling and steam production mechanism of gold nanofluids under uniform solar heating of 280 Suns. Various concentrations of gold nanofluids were produced and the generated steam was condensed and tested to reveal the presence of any nanoparticles.The study provides good insight to the surface boiling phenomenon of nanofluids and is in consonant with recent trend of investigation. However, there are several problems that need to be addressed before considering for publication in Applied Energy.1. The Abstract, in its current state is incomplete. It is more like a conclusion and needs to be re-written.Action: the abstract was rewritten with more focus on the novelty 2. The use of "gold nanofluids" should be mentioned in the Title and Abstract.Action: The title was slightly changed to reflect the content, and the was used in the title and the abstract in the revised version.3. In the statement: "For example, researchers [43] from Rice University", the Institution name should be replaced by the Authors' name.Action: T was used to replace the institution name in the revised version....

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Experimental investigation of a silver nanoparticle-based direct absorption solar thermal system

Cited by 177 publications

References 24 publications

Steam generation in a nanoparticle-based solar receiver

Steam generation in a nanoparticle-based solar receiver

Progress of nanofluid application in solar collectors: A review

Volumetric solar heating and steam generation via gold nanofluids

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