The total temperature glide of a refrigerant blend is defined as the temperature difference between the saturated vapor temperature and the saturated liquid temperature at a constant pressure. Another definition is the temperature difference between the starting and ending temperature of a refrigerant phase change within a system at a constant pressure.
Many refrigerant blends have temperature glide when they change phase in both the condenser and evaporator. In the evaporator, the refrigerant changes phase (evaporates) from a liquid to a vapor. In the condenser, the refrigerant changes phase (condenses) from a vapor to a liquid. Refrigerant blends exhibit temperature glide because there’s more than one molecule present in their compositional makeup. As these refrigerant blends change phase (evaporate and condense), there’s a change in their composition by preferential evaporation or condensation of the more or less volatile component in the blend. This process is referred to as blend fractionation.