Availability and irreversibility in thermodynamics

Connexion is made between Gibbs's "available energy of the system and medium" and the criterion of stability. The available energy concept is developed for systems which communicate only with the uniform medium or atmosphere and for systems which communicate with an additional reservoir of specified temperature. The treatment is extended to problems of transient and steady flow. A measure of departure from the ideal, the irreversibility, is defined and examined for its significance. Performance coefficients are devised for several classes of processes. Finally, the generality of the method is exhibited by analysis of a variety of thermodynamic phenomena.