What is the term for the phenomenon when an azeotropic blend of refrigerant condenses or evaporates at different temperatures?

The phenomenon in question occurs when an azeotropic blend of refrigerant separates into its individual components during the process of condensation or evaporation. This process is known as fractionation. In a fractionation scenario, the different substances in the mixture have distinct boiling or condensing points, leading to the separation of these components based on temperature differences when they transition from liquid to vapor or vice versa.

In the context of HVAC systems, understanding fractionation is crucial because it can affect the efficiency and operation of the refrigeration cycle. If refrigerants are allowed to fractionate, it can lead to changes in the refrigerant composition being circulated through the system, which can ultimately result in performance issues.

The other options relate to different concepts in thermodynamics and refrigeration. Segregation usually refers to the separation of a mixture into distinct components without necessarily involving temperature changes. Purification typically denotes the process of removing impurities from a substance, rather than a phase change process. The latent heat of fusion is the heat required to convert a solid into a liquid at its melting point and does not pertain to the behavior of refrigerant mixtures during condensation or evaporation.

Therefore, understanding the term fractionation is essential for HVAC professionals, as it directly impacts the performance of refrigerants and the