We discuss the method to construct finite-time thermodynamic potential
s proposed by Salamon, Andresen and Berry. We find that this method do
es not lead to suitable potentials for endoreversible thermal cycles.
We propose an alternative manner to define an endoreversible thermodyn
amic potential that permits to recover the appropriate endoreversible
(finite-time) efficiency for a Curzon and Ahlborn cycle. The proposed
endoreversible potential also allows us to obtain a generalized Clausi
us-Clapeyron equation for a finite time liquid-vapor transition. This
procedure is equivalent to those consisting in getting a finite-time C
lausius-Clapeyron equation by means of a generalized thermodynamic gra
phic method.