Effect of silica nanoparticle size on the stability and thermophysical properties of molten salts based nanofluids for thermal energy storage applications at concentrated solar power plants

Udayashankar Nithiyanantham, Abdelali Zaki, Yaroslav Grosu, Luis González-Fernández, A. Anagnostopoulos, M. E. Navarro, Y. Ding, Josu Mirena Igartua, Abdessamad Faik

Research output: Contribution to journalArticlepeer-review

Abstract

Molten salts-based nanofluids are attractive candidates for thermal energy storage applications due to their enhanced thermophysical properties. However, their stability remains an open issue. In the present work, the size effect of SiO2 nanoparticles on the stability and thermophysical properties of molten binary nitrate salt was studied. For that purpose, the effect of SiO2 based nanofluids was systematically studied by using in-situ high-temperature observations and zeta potential experiments. From the analysis, the nanofluids having nanoparticles larger than 450 nm demonstrate superior stability compared to the ones with nanoparticles of 27 nm. Moreover, in contrast to the case of 27 nm particles increase of viscosity was shown to be negligible for particles larger than 450 nm. The absence of specific heat capacity (Cp) or thermal conductivity enhancement for the cases of larger nanoparticles suggests that the development of molten salts-based nanofluids is bounded by the compromise between the stability and improvement of thermophysical properties, depending on the particle size. These results open a pathway for the development of stable molten salt-based nanofluids with enhanced thermophysical properties where the size of the nanoparticles must be optimized.

Original languageEnglish
Article number104276
Number of pages10
JournalJournal of Energy Storage
Volume51
Early online date5 Mar 2022
DOIs
Publication statusE-pub ahead of print - 5 Mar 2022

Bibliographical note

Funding Information:
The authors wish to express their sincere thanks to Yagmur Polat, Naira Soguero P?rez, Cristina Luengo and Nuria Varela for their technical support. The authors would also like to thank Gan Zhang for the help of zeta potential measurement. The authors gratefully acknowledge the nanouptake COST Action CA15119 for the funding of a short-term scientific mission (STSM), between CIC energigune and the University of Birmingham Center for Energy storage.

Keywords

  • Inorganic molten salt
  • Molten salt-based nanofluid
  • Nanoparticles size effect
  • SiO nanoparticles
  • Thermal energy storage

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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