The composite phase change material (PCM) used in the cold storage transportation system with phase change temperature of 0-5 ℃ are proposed in this paper. The material consists of capric acid and caprylic acid
and the mass ratio of its ingredients is 30:70. The composite was prepared by ultrasonic oscillations. The cooling curve method is used to test the phase change temperature of capric acid-caprylic acid in different mass fraction
the phase diagram is used to find the eutectic melting point and the ideal mass ratio is 30:70. The differential scanning calorimetry (DSC) test showed that the melting temperature of the PCM is 1.5 ℃ and the latent heat is 120.6 J/g. After 30 times and 60 times circulation of freezing and melting experiment
the phase change temperature and the latent heat were stable. The results showed that the composite has large potential in the cold storage system