Elsevier

Solar Energy Materials and Solar Cells

Volume 157, December 2016, Pages 1019-1025
Solar Energy Materials and Solar Cells

Thermal characterisation of binary sodium/lithium nitrate salts for latent heat storage at medium temperatures

https://doi.org/10.1016/j.solmat.2016.08.017Get rights and content
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Highlights

  • Two binary salts comprised of NaNO3–LiNO3 were prepared for latent heat storage.

  • Both binary salts exhibited excellent thermal cycling repeatability and stability.

  • A higher weight percentage of LiNO3 can affect the thermal performance.

  • Both binary salts work well below 450 °C.

Abstract

Latent heat storage in molten salt mixtures has been considered as a promising method for medium temperature solar thermal storage and industrial waste heat storage. The binary sodium/lithium nitrate salt mixture is one of the potential candidate materials. However there is limited information on their thermal performance except for their phase diagrams. In this paper, two binary salts, NaNO3–LiNO3 (46–54%) and NaNO3–LiNO3 (40–60%), were investigated to assess their suitability for medium temperature heat storage. The thermal properties and long term stability under multiple cycles of each binary salt pair were investigated using Differential Scanning Calorimetry (DSC). The chemical stability at elevated temperatures was tested using a Thermogravimetric Analyser (TGA). Both binary salts analysed have suitable melting temperatures (just under 200 °C) with relatively high latent heat values (>220 kJ/kg), both exhibiting good thermal and chemical stability.

Keywords

Latent heat storage
Binary salt
Phase change material (PCM)
Lithium nitrate

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