Thermal characterization of erythritol/expanded graphite composites for high thermal storage capacity

Expanded graphites (EGs) with various interlayer distances were combined with molten erythritol and then erythritol/EG composites as phase change materials (PCMs) and the composites were prepared by a simple blending and impregnating method. The effects of the additives of various interlayer distances of EGs on thermal behaviors were investigated by a thermal equilibrium technique. The latent heat and thermal cycling stability were evaluated by DSC traces. The results revealed that both the thermal conductivity and latent heat increased with increasing EG interlayer distance. In particular, erythritol/EG composites having the largest EG interlayer distance showed thermal conductivity of 3.56 W/m K and a latent heat value of 90 mass% of pure erythritol. The thermal cycling tests were performed 5 times and the latent heat of the erythritol/EG composites were constant from the third cycle onwards, demonstrating excellent thermal cycling stability.