A CO2 booster system employs a parallel compressor configuration where a smaller booster compressor handles low-pressure CO2 vapor from the low-temperature evaporator, improving system efficiency and capacity. The booster discharge feeds into the main compressor suction, reducing the primary compressor displacement requirements. This architecture delivers 10-20% efficiency improvements over single-compressor designs at moderate operating conditions.
Technical Details
Booster compressors operate at intermediate pressures between evaporator and main compressor discharge, typically 20-40 bar suction pressure. The configuration splits compression work across two stages, reducing discharge temperatures and improving volumetric efficiency. Main compressor suction receives pre-compressed vapor at higher density, reducing displacement needs by 15-25%. System control employs capacity modulation through booster unloading valves and variable displacement main compressors. Oil management requires careful separation and return systems to prevent pooling in low-pressure sections.
Applications and Benefits
CO2 booster systems optimize supermarket refrigeration plants and medium-temperature cascade configurations. Efficiency gains justify higher capital costs over 7-10 year equipment life through reduced electricity consumption. Design complexity requires experienced service technicians and specialized diagnostics equipment. Modern booster systems incorporate microprocessor control for adaptive pressure setpoints responding to real-time load conditions.