Optimization research on phase change cold storage module for refrigerated containers

Phase change energy storage technology can reduce temperature fluctuations during food storage and transportation, but there is a lack of research on cold storage capacity and efficiency considering the energy consumption of refrigeration units. In this paper, the experimental platform of the phase change cold storage module for the refrigerated container was established, and a two-dimensional heat transfer numerical model was developed and verified. The "cold storage coefficient Sc″" and "cold storage efficiency Se″" were defined to analyze the influence of different working conditions on cold storage capacity and cold storage speed. The results show that the longer the refrigerant pipe is, the faster the cold storage speed is, and the lower the energy consumption of the refrigeration unit is, but the cold storage energy storage capacity decreases to a certain extent. When the pipe length is about 33.6 m, the cold storage coefficient and cold storage efficiency are greater than 1, which means that the cold storage capacity and cold storage speed are kept at a high level. The increase in the pipe diameter has a limited effect on the cold storage efficiency and COP of the refrigeration unit, but will result in a significant decrease in the total energy storage capacity. When the pipe diameter is around 20 mm, the requirements of cold storage guarantee capacity and charging time can be met at the same time. With the increase in unit rated power, the cold storage efficiency can be significantly improved, but the COP of the unit decreases, and the higher the rated power of the unit, the greater the increase in the COP and cold storage speed of the refrigeration unit by increasing the pipe length. •The effects of pipeline layout and unit rated power on phase change cold storage were evaluated.•An efficient numerical heat transfer model of phase change cold storage module was established.•“cold storage coefficient SC” and “cold storage efficiency Se” were defined.