Application of a mobile CO2 system into the multi-temperature refrigerated container system.

A mobile carbon dioxide (CO2) refrigeration system is investigated to simultaneously provide a multi-temperature refrigerated container system (MTRCS) with the required cooling capacities. A two-evaporator system combined with multiple compression stages is considered. The high temperature (H.T.) evaporator is used to cool two-thirds of the container to 38°F (3.33°C), while the low temperature (L.T.) evaporator cools the remaining one-third of the container to -5°F (-20.56°C). Four possible cycle configurations are investigated and compared with each other. It is found that the cycle which employs a 3-stage compression concept incorporated with intercooling and flash tank economizing technology can achieve the best system performance and lowest discharge temperature. Moreover, an expander is used in this cycle to replace the expansion valve between the high-side pressure and intermediate pressure to recover the work loss during the expansion process leading to an even better system performance.