Improving system performance of the refrigeration unit using phase change material (PCM) for transport refrigerated vehicles: An experimental investigation in South China

In this study, a novel phase change cold storage unit (PCCSU) is proposed as a mobile refrigeration unit for transport refrigerated vehicles to improve its room temperature control performance. The PCCSU was installed at the front of the internal thermal insulated compartment and was charged through a refrigeration system during the off-peak period. The cold thermal energy in PCCSU was used to cool down the compartment. The change in temperature inside the compartment was obtained at different refrigerated temperatures, food transport-related risk, as well as energy cost. The results showed that the proposed PCCSU used in the thermally insulated compartment could significantly improve the temperature control performance. Besides, it also supports different temperature settings compared to the single temperature configuration in the conventional refrigeration system using phase change material. Specifically, the average air temperature of the internal compartment can be maintained at −12.3 °C, −14.5 °C, and −16.5 °C for 16.6 h, 14.7 h, and 10 h, respectively in the hot summer with an average ambient temperature of 29 °C. In addition, it lowers the minimum internal temperature by 3 °C and extends the compartment's temperature control time by 7.4–9.4 h compared to the conventional one. This study also found that the heat transfer efficiency between the PCCSU and the compartment is significantly improved due to the air supply system. In the present work, the safety of refrigerated vehicles using PCCSU technology could be significantly improved on the road. The energy cost for the PCCSU has a 15.4%–91.4% reduction compared to conventional mechanical refrigeration units driven by a diesel engine.