Theoretical and experimental evaluation of a refrigeration compressor operating under controlled conditions in a calorimetric chamber

Abstract

The use of compressors with a variable frequency drive has been an alternative to reduce energy in refrigeration. In this work, we evaluated some performance parameters of a refrigeration compressor working with electric motor drive frequencies under 50 Hz and 60 Hz, using the refrigerant R-404a. Thus, measurements at a constant temperature of 32.2 °C were subjected held in an calorimeter chamber. The quantities measured were: temperature of dry and wet bulb calorimeter chamber, air velocity in the evaporator, the wet bulb temperature and relative humidity in the face area of the evaporator and insufflation, suction and discharge pressures of the compressor, voltage and electric current for the compressor motor. Capacity and power consumed by the electric motor of the compressor drive, which were used to determine the coefficient of performance and the isentropic compressor efficiency were measured. Furthermore, it was held mathematical modeling and computer simulation of the cooling capacity of the compressor, using both the performance data provided by the manufacturer, as those from the measurements. The results showed that the pattern obtained by the measurements has minor deviations in relation to the developed using data from the manufacturer to the conditions studied. Moreover, the best performers are achieved to drive with frequency of 60 Hz compared to 50 Hz.