Análise experimental de um sistema de refrigeração operando com R404A e R449A

Abstract

This work presents an experimental analysis using the refrigerant R-449A as a possible alternative for refrigeration systems operating with R-404A, due to its lower GWP. The motivation was the need to introduce refrigerants that have fewer environmental side effects. This experiment was performed on a cooling bench with a nominal capacity of 5 TR (~15.6 kW). The parameters analyzed were the cooling capacity, the power consumed by the compressor, the coefficient of performance (COP), the discharge and suction temperatures of the compressor as well as their respective pressures and the superheating, there was also gathering of the temperatures of the water-cooling systems of the condenser and the refrigerated water. The environmental impact measurement was calculated using the TEWI methodology. Based on the data obtained, a performance analysis of both cooling fluids was performed. The tests were performed prioritizing the superheating in 10 K, while for each situation the condensation temperature was also varied. The evaporation temperature was controlled with a set point in some tests and in others, the expansion valve remained operating in automatic mode. The results revealed that the power consumed by the compressor using R-449A had a variation between 5.85% to 3.28% when compared with R-404A. The cooling capacity of the R-449A was higher in all analyses in the range of 2 to 6% compared to the R-404A. The COP was 1.07 to 11.45% higher using R-449A. Finally, the environmental impact calculation measured by the TEWI index corroborates the fact that the R-449A fluid is an excellent substitute for the R-404A, although the indirect damages are slightly lower, the direct impacts showed a 66.5% benefit to R-404A, due to its lower GWP value and mass used.