Preparation and characterization of composite material Na₂SO₄·10H₂O - KAl(SO₄)₂·12H₂O for thermal storage

Abstract

In the present paper, the preparation and characterization of composite material Na2SO4·10H2O - KAl(SO4)2·12H2O for thermal storage are reported. The co - melting method is employed to perform the preparation. The thermal properties and the step cooling behaviors of the composites are studied. The results show that: the phenomenon of phase separation disappears in the composite system with the mass ratio of 1 : 9 to 3 : 7 (Na2SO4·10H2O: KAl(SO4)2·12H2O), and the optimized mass ratio is about 2 : 8, which results in the lowest phase change temperature, the longest heat releasing platform of 41 min and a higher latent heat of 819.93J/g at 72.7 °C; the enthalpy remains higher value after 50 thermal cycles. Thus, this composite material has a potential as the phase change thermal storage material for low temperature application.