Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.
A prototype of a cascade refrigeration system using NH3 and CO, as refrigerants has been designed and built. The prototype is used to supply a 9 kW refrigeration capacity to a horizontal plate freezer at an evaporating temperature of -50 °C as design conditions. The prototype includes a specific control system and a data acquisition system. The paper describes the prototype and the experimental progm carried out to study the freezing process in the horizontal plate freezer. The experimental results include the freezing time, the temperature evolution in the product to be frozen, the refrigeration capacity of the facility, the electric power of the compressors, the COP's of the low and high temperature systems and the overall system COP. The results obtained would confirm that the use of C02 in the freezing process represents a viable alternative to the refrigerants currently in use.