Influence of Nanoparticles and Graphite Foam on the Supercooling of Acetamide

Acetamide is a promising phase change materials (PCMs) for thermal storage,but the large supercooling during the freezing process has limited its application. In this study, we prepared acetamide‐SiO 2 composites by adding nano‐SiO 2 into acetamide. This modified PCM was then impregnated into the porous graphite foam forming acetamide‐SiO 2 ‐graphite foam form‐stable composites. These composites were subjected to melting‐solidification cycles 50 times; the time‐temperature curves were tracked and recorded during these cycles. The time‐temperature curves showed that, for the acetamide containing 2 wt. % SiO 2 , the supercooling phenomenon was eliminated and the material’s performance was stable for 50 cycles. The solidification temperature of the acetamide‐SiO 2 ‐graphite foam samples was 65°C and the melting temperature was lowered to 65°C. The samples exhibited almost no supercooling and the presence of SiO 2 had no significant effect on the melting‐solidification temperature. The microscopic supercooling of the acetamide‐SiO 2 composite was measured using differential scanning calorimetry (DSC). The results indicated that when the content of SiO 2 was 1 wt. to 2 wt. %, the supercooling could be reduced to less than 10°C and heat was sufficiently released during solidification. Finally, a set of algorithms was derived using MATLAB software for simulating the crystallization of samples based on the classical nucleation theory. The results of the simulation agreed with the experiment results.