The Dead State

The purpose of this paper is to provide guidance for the selection of the dead state for exergy analysis, guidance that is especially important in applications to energy-conversion and materials processing plant engineering, and to ecology. First, the general definition of the dead state is provided, based on the concept of ‘the available energy of a body’ as originally presented by Gibbs. Gibbs ‘body’ can be any overall system, no matter how complex and a crucial point is that there is no need to include or have a ‘reference environment.’ On this groundwork, criteria underlying the selection of the appropriate dead state for a variety of practical engineering systems are referred to; while these cases are not exhaustive, they provide examples of the rationale for selection of an appropriate dead state for any case. Finally, the implications and relevance of the dead state on applications of exergy considerations to the issues of ecology and sustainability are discussed.