Influence of Nanoparticles and Graphite Foam on the Supercooling of Acetamide

Abstract EN

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-SiO2 composites by adding nano-SiO2 into acetamide.

This modified PCM was then impregnated into the porous graphite foam forming acetamide-SiO2-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.

% SiO2, the supercooling phenomenon was eliminated and the material’s performance was stable for 50 cycles.

The solidification temperature of the acetamide-SiO2-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 SiO2 had no significant effect on the melting-solidification temperature.

The microscopic supercooling of the acetamide-SiO2 composite was measured using differential scanning calorimetry (DSC).

The results indicated that when the content of SiO2 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.