Preparation and characterization of corn straw biochar doped ternary fatty acid composite phase change materials

In order to address the challenges of high energy consumption and carbon emission in cold chain logistics, a kind of biochar enhanced ternary fatty acid eutectic phase change material was developed. The ternary eutectic system was constructed with capric acid, lauric acid and n-octanoic acid, and the corn straw biochar was used as the carrier for heat conduction enhancement and leakage suppression. The phase transition temperature of the composite was 3.1 °C, the latent heat value was 104.9 J/g, and the thermal conductivity was increased by 1.853 W/(m·K), which was significantly higher than that of the unmodified system. The material leakage rate is only 6.49 %, and the latent heat attenuation is less than 2.3 % after 500 times of cold and heat cycles, which is showing excellent stability. In the refrigerator simulation experiment, in view of the importance of the 2 to 8 °C temperature zone for maintaining the quality and safety of fruits and vegetables, the material maintained this range for 560 min, which was approximately 36 % and 77 % longer than n-tetradecane and H₂O, respectively. Biochar provides an efficient temperature control solution for fruit and vegetable cold chain by optimizing the physical packaging and thermal conduction path through a multi-level pore structure.