A FEASIBILITY ANALYSIS OF REPLACING THE STANDARD AMMONIA REFRIGERATION DEVICE WITH THE CASCADE NH3/CO2 REFRIGERATION DEVICE IN THE FOOD INDUSTRY by

The thermodynamic analysis demonstrates the feasibility of replacing the stand-ard ammonia refrigeration device with the cascade NH3/CO2 refrigeration device in the food industry. The main reason for replacement is to reduce the total amount of ammonia in spaces like deep-freezing chambers, daily chambers, working rooms, and technical passageways. An ammonia-contaminated area is hazardous to human health and the safety of food products. Therefore, the pre-ferred reduced amount of ammonia is accumulated in the central refrigeration engine room, where the cascade NH3/CO2 device is installed as well. Further-more, the analysis discusses and compares two Carnot’s refrigeration cycles, one for the standard ammonia device and the other for the cascade NH3/CO2 device. Both cycles are processes with two-stage compression and two-stage throttling. The thermodynamic analysis demonstrates that the selected refrigeration cycle is the most cost-effective process because it provides the best numerical values for the total coefficient of performance with respect to the observed refrigeration cy-cle. The chief analyzed influential parameters of the cascade device are: total re-frigeration load, total compressor power, mean temperature of the heat exchang-er, evaporating and condensing temperature of the low-temperature part. Key words: natural refrigerants, ammonia, carbon dioxide, refrigeration device, refrigeration factor and load, reactive power, heat exchanger mean temperature, evaporating and condensing temperatur