Low Capacity Hermetic Type Compressor For Transcritical CO2 Applications

The use of carbon dioxide (CO2) as a refrigerant is recently considered for an increasing number of various applications including low capacity transcritical processes. Due to the fluid properties of CO2, the pressure ratio of the refrigeration process is rather low compared to common refrigeration processes while the pressure difference is high. Furthermore, the volumetric capacity of CO2 is higher than for traditional refrigerants. These facts result in special demands regarding the design of suitable components and especially compressors to be able to meet the demands regarding the overall systems performance. The paper discusses the lower limit of transcritical CO2 application and outlines a promising design concept for an applicable CO2-compressor.