Analysis of CO2 based refrigeration systems with and without ejector for simultaneous pasteurization and chilling of milk

In this study, a transcritical CO2 refrigeration system suitable for simultaneous pasteurization and chilling of milk in a dairy plant has been analysed. Performance comparison is made between CO2 systems with ejector (RCEP) and a conventional CO2 system without ejector (CRCP). Results are obtained for different arrangements of internal heat exchanger (IHX) in the flow line with a regenerative milk heat exchanger (HXD) for heat recovery. From the results, the optimum operating condition for maximum specific milk flow rate (m˙mw) is obtained. Results show that RCEP1, which uses an ejector and the internal heat exchanger in between the two gas coolers, offers around 13% better productivity compared to CRCP. Investigation on primary energy consumption of the transcritical CO2 system and systems employed in dairy plant conventionally for pasteurization show a substantial margin in energy savings for RCEP.