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Expanded graphite/paraffin/silica phase change composites with high thermal conductivity and low permeability prepared by the solid-state wet grinding method.
- Source :
-
Solar Energy Materials & Solar Cells . Mar2022, Vol. 236, pN.PAG-N.PAG. 1p. - Publication Year :
- 2022
-
Abstract
- In this study, expanded graphite (EG)/paraffin (PA)/silica (SiO 2) composite phase change materials (PCM), with good thermal conductivity and impermeability, were fabricated for potential applications in solar energy. The EG-PA was first prepared by vacuum adsorption and then encapsulated by SiO 2 through solid-phase wet grinding in the presence of sodium silicate. Our results show that the EG-PA-SiO 2 composite have optimal properties when the mass ratio of raw material is PA: sodium silicate: H 2 O = 1:9:2:8. The latent heat of melting of the EG-PA-SiO 2 composite prepared at this mass ratio is 106.2 J/g. The core material loss ratio, after washing with petroleum ether, is 4.79%. The thermal conductivity is 2.053 W/m·K, which is 8.5 times higher than that of pure paraffin wax, and the melt permeability is 9.35% after 120 min at 60 °C. Under simulated sunlight, the time required for the composite material to change from 30 °C to 65 °C is reduced by 70.78% compared to PA and the heat absorption and release times are nearly unchanged under multiple cycles. These results indicate that the material has a stable photothermal conversion efficiency. [Display omitted] • Expanded graphite, paraffin and silica composites were made by solid-phase wet grinding method. • Silica encapsulated the composite, reducing leakage. • Composites showed improved thermal conductivity and impermeability. • The composite has stable photothermal conversion, and there is no obvious leaking sign. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09270248
- Volume :
- 236
- Database :
- Academic Search Index
- Journal :
- Solar Energy Materials & Solar Cells
- Publication Type :
- Academic Journal
- Accession number :
- 154374812
- Full Text :
- https://doi.org/10.1016/j.solmat.2021.111484