Preparation and heat transfer model of stereotyped phase change materials suitable for cold chain logistics

Phase change cold storage materials have some defects such as easy leakage and poor thermal conductivity in practical application. In the cold chain logistics, the cold storage panels are used as the cold storage devices of the refrigerated trucks, choosing the right way of charging can shorten the charging time of cold storage panel, improve the charging efficiency, save the overall transport time of the cold chain, and improve the transport efficiency. A kind of phase change cold storage material apply to 0-8 degrees C cold chain logistics was developed by means of step cooling experiment and differential scanning calorimeter, expanded graphite (EG) was added to enhance thermal conductivity and establish porous structure. The heat transfer model of cold storage and charging was established, and the coupling relationship between the charging mode and the charging rate of the cold storage panel was analyzed. The results show that: After adding 8 % expanded graphite (EG), the mass loss rate of Caprylic Acid -Lauryl Alcohol (CA-LA) composite phase change material was 7.73 %, it can effectively prevent leakage of phase change materials. And the phase transition temperature was -0.7 degrees C, latent heat value was 170.4 J/g, thermal conductivity was 1.411 W/(m center dot K), and thermal conductivity was increased by 6.17 times. The charging efficiency of the cold storage panel with a built-in charge cold coil was obviously higher than that of the cold storage panel placed in a low temperature environment. The charging time can be shortened by 58.1 % with the same mass of the cold storage material. The research results have certain promoting significance and theoretical support for the adoption of phase change material cold storage technology in cold chain logistics.