Investigation on thermal properties of capric–palmitic–stearic acid/activated carbon composite phase change materials for high-temperature cooling application

Abstract

Based on the theory calculation, the capric–palmitic–stearic (CA–PA–SA) ternary eutectic mixture was prepared with melting and freezing temperature of 19.93 and 16.84 °C, respectively. Regarding CA–PA–SA as phase change materials (PCMs), and activated carbon (AC) as the additive, the CA–PA–SA/AC composites can be prepared by physical blend method which can be applied to high-temperature cooling application in solar cooling systems, radiant cooling systems, etc. A comprehensive study of the structure, thermal properties, thermal stability, thermal durability and thermal storage-release characteristic of CA–PA–SA/AC composites was conducted through the FT-IR, DSC, TG, accelerated thermal cycling test and melting–freezing experiments. The results show that, with the increase in AC content, the melting temperature of CA–PA–SA/AC composites decreases gradually, whereas the freezing temperature increases. And the addition of AC can enhance the thermal stability, the thermal durability and the thermal storage-release rate of PCM: the thermal stability of PCM1–PCM4 is much greater than that of pure mixture, and its storage time was reduced by 37, 31, 23 and 9 %, respectively, while its release time was reduced by 67, 58, 48 and 43 % respectively.