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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-472-4

ISBN Online: 978-1-56700-471-7

3rd Thermal and Fluids Engineering Conference (TFEC)
March, 4–7, 2018, Fort Lauderdale, FL, USA

A core-shell structured PCM with Na2SO4 encapsulated by SiO2 for high temperature thermal storage

Get access (open in a dialog) pages 621-624
DOI: 10.1615/TFEC2018.ens.022311

Resumo

In latent heat thermal storage, macro- or microencapsulation of phase change materials (PCMs) can benefit PCM performance. This work proposed a novel chemical method for microencapsulation of inorganic PCM for high temperature thermal storage. This method encapsulates Na2SO4 (PCM) with SiO2 shell via the sol-gel technique. The SiO2 shell is a fire-resistant material and can effectively inhibit the liquid leakage during solid-liquid phase change process. Comprehensively considering the thermal conductivity, thermal stability, melting temperature, and latent heat, the silica mass fraction has been optimized at 5.4% of the composite. In this encapsulation, silica particles were observed decorated on the surface of large Na2SO4 particle and perfect core-shell structures were obtained for the nano-size Na2SO4 particle. The thermal conductivity of the encapsulated Na2SO4@SiO2 has been enhanced by 21% compared to pure Na2SO4 at 800°C. The initial phase change temperature, peak temperature and latent heat of this encapsulated PCM are 885.2 °C, 887.9 °C and 170.6 J/(g. K), respectively. The TG/DSC shows that this PCM has almost no mass loss (<1 %) under calcination temperature of 1000°C. Thermophysical properties of the encapsulated Na2SO4@SiO2 varied marginally after 50 thermal cycle tests.