Influence of nanoparticles and graphite foam on the supercooling of acetamide

Abstract

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-SiOcomposites by adding nano-SiOinto acetamide. This modified PCM was then impregnated into the porous graphite foam forming acetamide-SiOgraphite 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 the supercooling phenomenon was eliminated and the material's performance was stable for 50 cycles. The solidification temperature of the acetamide-SiOgraphite foam samples was 65°C and the melting temperature was lowered to 65°C. The samples exhibited almost no supercooling and the presence of SiOhad no significant effect on the melting-solidification temperature. The microscopic supercooling of the acetamide-SiOcomposite was measured using differential scanning calorimetry (DSC). The results indicated that when the content of SiOwas 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.