ON ENDOREVERSIBLE THERMODYNAMIC POTENTIALS

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.