Simulation and experimental investigation of a multi-temperature insulation box with phase change materials for cold storage

In terms of cold chain logistics, China is less developed with most refrigerated transport being mechanical compression refrigeration. To improve the economy of logistics and ensure the quality of fruits and vegetables in refrigerated transportation, a multi-temperature insulation box with different phase change materials (PCMs) was designed for cold storage in this work. The efficiency of PCMs was evaluated using a differential scanning calorimeter (DSC) and thermal conductivity tester. The experimental results reveal phase transition temperatures of 7.1 and −2.5 °C, latent heats of 146.1 and 256.2 J/g, and thermal conductivities of 0.2832 and 0.9427 W/(m·K) of PCM1 (n-octanoic acid-myristic acid composite) and PCM2 (potassium sorbate-water composite), respectively. Combined with vacuum insulation technology, a multi-temperature zone insulation box for cold storage was constructed. A three-dimensional unsteady model was established, and the temperature and velocity fields in different parts of the box were analyzed, especially the melting process of PCMs. An insulation box temperature test system was established using good supply practice (GSP). The experimental results reveal that temperature zones 2 (medium zone) and 3 (low zone) of the insulation box can be kept cold at 7–9 °C for about 13 h and at −2–0 °C for about 14 h, respectively. The results suggest that the designed multi-temperature storage insulation box is an effective transportation equipment for cold chain logistics.