Point e is chosen so that it is on the saturated liquid line with h = 100 ⁠ kJ / kg ⁠ . It corresponds roughly with p = 13 bar and T = 108 K. Throttling from this point to a pressure of 1 bar ends in the two-phase region (point f). This means that a mixture of gas and liquid leaves the throttling valve. Since the enthalpy is an extensive parameter, the enthalpy in f ( h f ) is equal to the enthalpy in g ( h g ) multiplied by the liquid fraction in f ( x f ) plus the enthalpy in h ( h h ) multiplied by the gas fraction in f (1 − x f ) . So