A new composite phase change material composed of sodium formate (HCOONa)

ammonium chloride (NH4Cl)

and water is prepared for low-temperature cold chain logistics below ?23 °C. The material (mass ratio of HCOONa-NH4Cl-H2O is 2:1:7) is named SF70. The supercooling

thermal conductivity

and phase separation of SF70 are optimized by adding nanomaterials and thickeners. Then

experiments are conducted on the circulation and application of the optimized material in an insulated container. The experimental results show that the 0.4% TiO2 nanomaterial exhibits the best effect on improving the supercooling and thermal conductivity of the composite; 1% PAAS can effectively eliminate phase separation. The optimized material is composed of SF70 + 0.4% TiO2 + 1% PAAS

for which the phase change temperature

latent heat

supercooling

and thermal conductivity are ?29.9 °C

255 kJ/kg

2.8 °C

and 0.652 2 W/(m?K)

respectively. After 200 cycles

the thermal properties of the material remain stable. When the phase change material is used in an insulated container

meatballs can be kept below ?23 °C for more than 20 h

which meets the requirements of short-distance cold chain transportation.