Performance study on expand graphite/organic composite phase change material for cold thermal energy storage

Octanoic-myristic acid binary eutectic mixture (OA-MA) was prepared as a base liquid. A novel shaped composite PCM of OA-MA/expanded graphite (EG) with an optimum mass ratio (OA-MA:EG=93:7) was prepared by uniformly absorbing OA-MA into the porous structure of the EG. The micro structure was observed by scanning electronic microscopy (SEM). The phase change temperature and latent heat were measured by DSC.The thermal conductivity was measured by Hot Disk thermal constant analyzer. Besides, the thermal cycling tests was carried out for 100 times to validate the stability of OA-MA/EG. The phase change temperature of OA-MA was 7.1 ℃, the latent heat was 146.1 J/g, and the thermal conductivity was 0.2971 W/(m·K). After adding the 7 % EG, the phase change temperature of OA-MA/EG was 6.8 ℃, the latent heat was 136.3 J/g, and the thermal conductivity was 0.9975 W/(m·K), 2.36 times higher than OA-MA. The thermal cycling tests showed that OA-MA/EG composite PCM has a good thermal reliability. All the results show that the composite PCM has great prospect in the practical application to medical refrigerated transportation system which temperature range is 2~8 ℃.