Performance Evaluation of Ejector Based CO₂ System for Simultaneous Heating and Cooling Application in an Indian Dairy Industry

Abstract India is ranked first in milk production, and its goal is to increase annual production to 300 million tons by 2024. The dairy industry requires multi-temperature cooling and simultaneous heating. In the present study, the ejector based transcritical CO₂ system with two evaporators (LT at -10°C, MT at 0°C) is analyzed and proposed for fulfilling both cooling and heating demands in the dairy industry. Ejector based systems with and without internal heat exchanger are analyzed and compared. The effects of gas cooler outlet temperature, receiver pressure and gas cooler pressure on the performance of the system are investigated by energy and exergy analysis. The gas cooler pressure is analyzed for achieving the desired pasteurization temperature. The internal heat exchanger not only reduces the minimum gas cooler pressure required for the pasteurization temperature but also increases the system COP and exergy efficiency by 6.4% and 4.5% respectively. Second law analysis shows that the maximum exergy efficiency of the system is 38.4%.