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The temperature stability and development of a broadband silver nanofluid for solar thermal applications

The temperature stability and development of a broadband silver nanofluid for solar thermal applications
The temperature stability and development of a broadband silver nanofluid for solar thermal applications
This paper details an investigation into the synthesis and temperature stability testing of silver-nanofluids, aimed at producing three silver-based nanofluids with distinctive morphologies and absorption characteristics suitable for enhanced efficiency volumetric solar-thermal collectors, which could be combined with a suitable thermal storage system to provide low-carbon heating and hotwater. When combined the three silver-based nanofluids were designed to give spectrally broadband absorption of the incident solar radiation in the 300 – 1300 nm range. The starting point was a previously developed synthesis producing triangular silvernanoparticles with a strong absorbance in the 850 – 950 nm range (Nanofluid 1). The effect of changing various reagents in the synthesis was then investigated. Increasing the silver nitrate concentration and changing the silver to reducing agent ratio produced Nanofluid 2 (strong absorbance in 650 -750 nm range), containing smaller more rounded triangular nanoparticles. For Nanofluid 3, a two-step synthesis had to be adopted, with a seed nanofluid made initially by lowering the concentration of reducing agent (sodium borohydride) and oxidizing agent (hydrogen peroxide). Additional silver nitrate and reducing agent were added, giving a more concentrated nanofluid, containing small silver nanodiscs, with a 450 nm absorption maximum. These three nanofluids were combined together to give a broadband absorber and for the first time, the stability to a temperature of 70°C measured using UVvis-IR spectroscopy. Results indicate that although a broadband absorber based on silver can be designed it is not suitable for use without an appropriate stabilization strategy, due to a lack of spectral stability with temperature.
Silver nanoparticles, Stability, Thermal storage, nanofluids, solar thermal collectors
2352-4847
87-96
Kimpton, Harriet Jill
30c744e7-3f80-4a81-a53c-03f44074a805
Zhang, Xunli
d7cf1181-3276-4da1-9150-e212b333abb1
Stulz, Eugen
9a6c04cf-32ca-442b-9281-bbf3d23c622d
Kimpton, Harriet Jill
30c744e7-3f80-4a81-a53c-03f44074a805
Zhang, Xunli
d7cf1181-3276-4da1-9150-e212b333abb1
Stulz, Eugen
9a6c04cf-32ca-442b-9281-bbf3d23c622d

Kimpton, Harriet Jill, Zhang, Xunli and Stulz, Eugen (2021) The temperature stability and development of a broadband silver nanofluid for solar thermal applications. Energy Reports, 7 (S2), 87-96. (doi:10.1016/j.egyr.2021.02.049).

Record type: Article

Abstract

This paper details an investigation into the synthesis and temperature stability testing of silver-nanofluids, aimed at producing three silver-based nanofluids with distinctive morphologies and absorption characteristics suitable for enhanced efficiency volumetric solar-thermal collectors, which could be combined with a suitable thermal storage system to provide low-carbon heating and hotwater. When combined the three silver-based nanofluids were designed to give spectrally broadband absorption of the incident solar radiation in the 300 – 1300 nm range. The starting point was a previously developed synthesis producing triangular silvernanoparticles with a strong absorbance in the 850 – 950 nm range (Nanofluid 1). The effect of changing various reagents in the synthesis was then investigated. Increasing the silver nitrate concentration and changing the silver to reducing agent ratio produced Nanofluid 2 (strong absorbance in 650 -750 nm range), containing smaller more rounded triangular nanoparticles. For Nanofluid 3, a two-step synthesis had to be adopted, with a seed nanofluid made initially by lowering the concentration of reducing agent (sodium borohydride) and oxidizing agent (hydrogen peroxide). Additional silver nitrate and reducing agent were added, giving a more concentrated nanofluid, containing small silver nanodiscs, with a 450 nm absorption maximum. These three nanofluids were combined together to give a broadband absorber and for the first time, the stability to a temperature of 70°C measured using UVvis-IR spectroscopy. Results indicate that although a broadband absorber based on silver can be designed it is not suitable for use without an appropriate stabilization strategy, due to a lack of spectral stability with temperature.

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EGYR_Proceedings_Kimpton H_2021 final logos removed - Accepted Manuscript
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More information

Accepted/In Press date: 17 February 2021
e-pub ahead of print date: 28 May 2021
Keywords: Silver nanoparticles, Stability, Thermal storage, nanofluids, solar thermal collectors

Identifiers

Local EPrints ID: 447176
URI: http://eprints.soton.ac.uk/id/eprint/447176
ISSN: 2352-4847
PURE UUID: 4e12ac3e-485e-4652-bd68-87eb05e96378
ORCID for Harriet Jill Kimpton: ORCID iD orcid.org/0000-0002-3219-217X
ORCID for Xunli Zhang: ORCID iD orcid.org/0000-0002-4375-1571
ORCID for Eugen Stulz: ORCID iD orcid.org/0000-0002-5302-2276

Catalogue record

Date deposited: 04 Mar 2021 17:40
Last modified: 26 Nov 2021 02:52

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Contributors

Author: Harriet Jill Kimpton ORCID iD
Author: Xunli Zhang ORCID iD
Author: Eugen Stulz ORCID iD

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