Shape effect of Al2O3 nanoparticles on the thermophysical properties and viscosity of molten salt nanofluids for TES application at CSP plants. (25th March 2020)

• Record Type: Journal Article
• Authors: Nithiyanantham, Udayashankar; González-Fernández, Luis; Grosu, Yaroslav; Zaki, Abdelali; Igartua, Josu M.; Faik, Abdessamad
• Is Part Of: Applied thermal engineering. Volume 169(2019)
• Publication Date: 2020-03-25
• Subjects: Al2O3 nanoparticles -- Nanofluids -- Thermophysical properties -- Inorganic molten salt -- Sensible heat storage -- Thermal energy storage; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2020.114942
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Two nanofluids with enhanced properties have been developed for CSP application. A novel simple dry method was validated to prepare nanofluids. The new dry method can be used as an efficient on-site industrial method. The economic benefits of the use of these nanofluids in CSP plants were highlighted. Abstract: Two Al2 O3 based nanofluids have been developed to increase the thermophysical properties of the molten salts used for thermal energy storage application at concentrated solar power plants. A novel simple dry preparation method by using a physical shaking technique was demonstrated in the present research work. A good dispersion of 1 wt% Al2 O3 nanomaterials with different shapes (nanospheres and nanorod) in the base eutectic salt, i.e. 51 wt% NaNO3 – 49 wt% KNO3, was achieved by a shaking time of 15 min. Two different shaped Al2 O3 nanomaterials, i.e. nanoparticles (Al2 O3 -NPs) and nanorods (Al2 O3 -NRs), have been used to prepare the nanofluids. Their stability and thermophysical properties have been studied by means of TGA, DSC, LFA, Rheometry and Dilatometry. The main aim of the present study is to investigate the nanoparticle shape effects on the enhancement of the thermophysical properties of the base inorganic salt. The Al2 O3 -NPs based nanofluid (Al2 O3 -NPs-nanofluid) and Al2 O3 -NRs based nanofluid (Al2 O3 -NRs-nanofluid) show enhancements of the specific heat capacity (Cp ) in solid and liquid states of ~3% and ~6%, respectively. The thermal conductivity analysis demonstrates enhancements of 12% and 20% in solid states and 16% and 12% in liquid state for Al2 O3 -NPs-nanofluid and Al2 O3 -NRs-nanofluid, respectively. The viscosity increases of 25% and 37% were observed for Al2 O3 -NPs-nanofluid and Al2 O3 -NRs-nanofluid, respectively.