Abstract: Cold storage using phase change materials (PCMs) has wide applications on the transportation of food and medical products. This article presents a study on the performance of a cold storage device with two PCMs in a layered structure. Tridecane and dodecane were used as the PCMs, which have phase change temperatures and phase change enthalpies of −5.4 ℃ and 132 kJ/kg, and −9.6 ℃ and 173 kJ/kg, respectively. The main objective of the study was to find the best combination of the two PCMs giving the longest storage period. The results showed that the combination with tridecane placed outside and dodecane inside gave the longest time for the inner wall temperature to change from −15 ℃ to 0 ℃ although the combination only had the 3rd largest total latent heat. Same conclusions were obtained with pure dodecane, which was longer than the unit with pure tridecane and tridecane located outside layer and dodecane inside. Placing the PCM with a higher phase change temperature in the outside layer reduced the heat transfer rate from the ambient to the internal core of the cold storage unit, leading to an increase in the cold storage period and improvement in the cold storage performance.

Key words: phase change materials, cold storage, multi-layer structure