OPTIMIZATION OF CASCADE REFRIGERATION SYSTEM TO ACHIEVE LOWER TEMPERATURES

Abstract

Achieve ultra-low temperatures is usually possible due to the use of cascade configurations refrigeration systems. Commonly, the observed results do not match the expected theoretical predictions. Therefore, in order to increase thermal efficiency and reach lower temperatures, adjustments and modifications in mechanical components of refrigeration system, in refrigerant fluids charges, and in general parts arrangement can be done. The system presented herein features a cascade configuration that uses R-404a and R-508b, and was previously able to reach -70°C. This study investigates the impact of optimization changes made in this existing cascade system, regarding the use of a more powerful compressor, in order to achieve -86°C inside the freezer. A series of tests was conducted for each one of the changes, and  this paper presents the complete methodology used, as well as the results found. As we will be able to notice, the results did not match the expected temperature, but contributed to the evolution of the experiment.