Which refrigerant is commonly associated with small centrifugal compressors, per the source?

• A. R-12
• B. R-11
• C. R-22
• D. R-134a

Answer: (A)

Understanding which refrigerant pairs best with a centrifugal compressor starts with how the fluid’s properties fit the machine’s design. For the small centrifugal compressors described in the source, R-12 was commonly used because its thermodynamic behavior and compatibility with the lubricants and seals typical of these compact units helped deliver reliable performance within the operating pressure and temperature ranges of those systems. This historical pairing made R-12 the refrigerant most frequently associated with small centrifugal compressors in the material you’re studying. Other refrigerants are associated with different equipment families or newer designs: R-11 appears in some large centrifugal machines, while R-22 and R-134a are more commonly linked to other types of compressors or newer technologies and not the typical small centrifugal pairing described here.