Experimental study on cold storage box with nanocomposite phase change material and vacuum insulation panel

To maintain the quality of fruits, vegetables, and other agricultural products during cold chain transportation, a constant temperature in the range of −5°C to 8°C is optimal. In this work, a thermal storage material, containing sodium polyacrylate, multiwalled carbon nanotubes (MWCNTs), and water, was prepared in a polyethylene cold storage plate, which was then placed in a vacuum insulation box. The prepared material exhibits high economic efficiency, a phase transition temperature of −0.037°C, and latent heat of 335.4 J/g sodium polyacrylate (PASS) system. The thermal conductivity of 1% sodium polyacrylate and water was 0.757 W/(m·K), which increased by 19.17% to 0.9021 W/(m·K) after the addition of 0.1% MWCNT. The cryogenic transport box was constructed with composite nanomaterial and vacuum insulation plate, and yoghurt was used as the test sample. The experimental results show that the nanocomposite phase change material can effectively maintain cold temperatures in the box for 87 hours, and the viscosity and pH of yoghurt remained in an acceptable range for this time period. The vacuum insulation board also effectively ensures the quality of food, good cold insulation performance, and therefore high feasibility.