DESIGN AND CONSTRUCTION OF AN AUTOMATED HOT-GAS CYCLE CALORIMETER FOR CARBON DIOXIDE COMPRESSORS
Alexsandro dos Santos Silveira1; Everton Machado1; Fernando Testoni Knabben1
1 UFSC
doi:10.20906/CPS/COB-2015-0708
Resumo
The present work proposes a novel design of an automated hot-gas cycle calorimeter for CO2 compressors. The proposed refrigeration cycle, with three pressure levels and two metering valves coupled with stepper motors, provided an automatic control of the discharge and suction pressures and made the calorimeter much more agile and stable for a wide range of operating conditions. For this end, a specific control system was studied, and a 1.28 cm3 variable speed rolling piston compressor was tested. A set of 72 experimental points could be measured within only 2 weeks. The compressor speed was varied from 35 to 65 Hz, the suction pressure from 20 to 50 bar and the discharge pressure from 75 to 105 bar. The ambient and suction line temperatures, on the other hand, were held at 32 ºC. In addition, an empirical and a physical-based model were analyzed in order to generate the compressor efficiency curves. The results indicated that the physical-based model was the one that better represented the behavior of the compressor.
Palavras-chave: calorimeter; variable speed compressor; carbon dioxide; refrigeration; hot-gas