COMPARATIVE ANALYSIS OF ELECTRIC ENERGY CONSUMPTION OF CASCADE SYSTEM R134a/CO2 WITH SINGLE-STAGE R404A AND TWO-STAGE CO2 INSTALLATION

Abstract

The paper analyzes the electric energy consumption of three different refrigeration installations: cascade refrigeration system with R134a in the high-temperature circuit and CO2 in the low-temperature circuit, single-stage refrigeration system operating with R404A, and two-stage transcritical CO2 system. The indirect impact of the refrigeration system on global warming through electric energy consumption was examined. Thermodynamic cycles of these installations have been described and models have been developed to analyze the electric energy consumption required to drive the compressor as the largest consumer, for the cooling capacity of the evaporator 5,7 kW at evaporation temperature -30 °C for meteorological 2017, in the city of Belgrade. As a basis for comparative analysis, the existing cascade refrigeration system, which is located in the Laboratory for Thermal Science at the Faculty of Mechanical Engineering in Belgrade, was selected.