Preparation and Performance of Na₂SO₄·10H₂O-Na₂HPO₄·12H₂O Eutectic Hydrated Salt Phase Change Nanofluids Modified by Nano-SiC

It is important to enhance their performance of supercooling and low thermal conductivity in hydrate salt phase change materials. A hydrophilic silicon carbide (nano-SiC) was prepared via treating SiC nanoparticles in HF/HNO₃ with Na₂SO₄·10H₂O-Na₂HPO₄·12H₂O eutectic hydrated salt as basic materials, and the phase change nanofluids materials (nano-SiC EHS PCMs) with Na₂SiO₃·9H₂O and nano-SiC were composited. The results show that the modified nano-SiC can be dispersed in EHS PCMs. The synergistic effect of Na₂SiO₃·9H₂O and nano-SiC can reduce the supercooling degree to 0.3 ℃ without the phase separation. The thermal conductivity of nano-SiC EHS PCMs enhances both in solid and liquid. The energy storage time of EHS PCMS with 0.2% (in mass) nano-SiC is decreased by 21.8%. The enthalpy of melting and crystallization of EHS PCMs with 0.15% nano-SiC is 267.3 J/g and 231.4 J/g, respectively. The enthalpy of nano-SiC EHS PCMs is stable after 1000 heating and cooling cycles, indicating that nano-SiC EHS PCMs have a great thermal cyclic stability.