Design and freezing performance study of a CO₂ plate freezer at -50°C evaporation temperature

Efficient cooling and freezing systems using natural refrigerants offer a sustainable solution for food loss and waste reduction in the food supply chain, particularly by preventing the loss of raw materials. Plate freezers are typical components in modern automated production and processing facilities for freezing processed foodstuffs. At NTNU, a real-sized industrial plate freezer has been implemented into a dedicated CO₂ refrigeration system in the laboratory infrastructure. Due to CO₂ liquid circulation inside the plates, the unit can provide more than 100 kW of cooling capacity at evaporation temperatures between -30 and -50°C. This study aimed to design the test facility for the proposed plate freezer and numerically investigate the freezing performance. Component sizing was performed using established principles and techniques to accommodate the refrigerant properties. The freezing time evolution for different product masses was analyzed. Furthermore, the effects of evaporation temperature on the freezing time were investigated.