This method is similar to UNIFAC TDEP-1, in that the binary group energy interaction parameter was given temperature dependence by development of a three parameter form. The combinatorial and residual calculations are not modified from the original UNIFAC expression.
The purpose of this modification was to improve the accuracy of the UNIFAC method by accounting for temperature effects.
See "Modifications to UNIFAC" in the PRO/II Reference Manual, Volume I, Chapter 2, for additional information on this method.