The unconventional solution model of mobile order theory, which has previously been shown to provide a very accurate thermodynamic description of anthracene and pyrene solubilities and chemical potentials in binary alcohol + alcohol solvent mixtures, is extended to other thermodynamic excess functions. An expression is derived for predicting excess molar enthalpies of ternary inert hydrocarbon + two alcohol systems from measured binary data. Applications and limitations of the newly derived predictive expression are assessed using published enthalpy data for 11 ternary alkane + 1-alcohol + 1-alcohol systems.