Highly-efficient cold energy storage enabled by brine phase change material gels towards smart cold chain logistics

Cold chain logistics is an important technology to ensure the quality and preservation of food, drugs and biological samples. In this work, novel brine phase change material gels (BPCMGs) are proposed by loading the eutectic brine in super absorbent polymer (SAP) to realize the highly-efficient cold energy storage towards the cold chain transportation. Potassium chloride (KCl) and ammonium chloride (NH4Cl) are dissolved in water to form the eutectic brine PCM on account of its phase change temperature near −21 °C for the refrigerated transport of aquatic products and biological samples. SAP with excellent brine adsorption capacity can provide the free-standing feature for the BPCMGs. The resulted BPCMGs demonstrate eliminated supercooling, high latent heat of 230.62 Jg−1, high thermal conductivity of 0.589 Wm−1 K−1 and high cost-effectiveness of 7.63 × 10−6 $J−1. The BPCMGs also possess stable thermophysical properties after 200 cycles. Taking advantages of the above merits, the BPCMGs are applied in the cold chain logistics of aquatic products and biological samples. The cold storage times reach 21.44 h and 16.37 h for aquatic products and biological samples when the stored cold energy is 691,800 J. Furthermore, the temperatures and locations of the cold storage box can be real-time monitored remotely by equipping with temperature sensor, GPS positioning system and a smart phone. This work creates a state-of-the-art alternative for the next-generation cold energy storage materials and cold energy storage equipment.