Preparation and characterization of new nano-particle mixed as thermal storage material

Highlights: • The thermal conductivity of PCMs was related to the content of two mixed salts and temperature. • Nano-C improved the heat transfer of PCMs, increased by 66.63%. • The addition of nano-C reduced the supercooling of PCMs, decreased by 37.9%. • The PCMs(C/KAl(SO₄)₂·12H₂O/Na₂SO₄·10H₂O) had good thermal cycle stability. -- Abstract: A new nano-particle mixed as thermal storage material (CMN) was prepared with KAl(SO₄)₂·12H₂O (M) and Na₂SO₄·10H₂O (N) and nano-particle carbon (C) as a thermal conductive agent for thermal conductivity enhancing. The detailed thermo-physical properties and thermal energy storage performance were studied, including thermal conductivity, phase change temperature, latent heat, supercooling degree and thermal cycling stability. The results indicated that C, KAl(SO₄)₂·12H₂O and Na₂SO₄·10H₂O were physically mixed. The thermal conductivity of PCM increased from 0.546 W/(m·K) to 0.910 W/(m·K) because of the addition of 1 wt%C. 1 wt% C suppressed the subcooling of PCM from 2.9 °C to 1.8 °C. The DSC revealed that the phase change temperature and latent heat of CMN were 65.68 °C and 132.2 J/g. It indicated that CMN had good thermal stability after 100 thermal cycle tests.