Which term describes the phenomenon that components separate into layers within a refrigerant blend?

• A. Fractionation
• B. Condensation
• C. Evaporation
• D. Sublimation

Answer: (A)

Fractionation describes how components in a refrigerant blend separate into layers because they have different volatilities. In zeotropic blends, the more volatile component tends to vaporize first while the less volatile component stays in the liquid phase. As the mixture experiences temperature and pressure changes, the liquid and vapor become richer in different components, which can lead to layering or stratification of the mixture over time. This phenomenon is important when charging, recovering, or operating systems with blends, because the changing composition affects performance and may require careful handling. The other terms refer to phase changes of a single substance (condensation, evaporation, sublimation) and don’t capture the separation of components within a multi-component refrigerant blend.