On the concept of exergy and available potential energy

A systematic derivation of the concepts of available potential energy of Lorenz and Van Mieghem from an extended concept of exergy is performed. This procedure leads to an extension of Van Mieghem's global theory to a local formulation which can be used in limited‐area models. In the limit of small amplitude motion it is shown that the extended exergy reduces to the available potential energy of Boussinesq‐approximated models. Moreover, Shepherd's concept of pseudoenergy is extended in order to deal with diabatic and irreversible processes.