Available Energy and Exergy
An "available energy" is defined for every state of any system. The definition is independent of (a) the concept of work. (b) any reference environment, and (c) the makeup of the system (e.g. "macro" or "micro). On the basis of this available energy, given any composite system, the contribution of each subsystem to the available energy -- that is, the exergy content of a subsystem -- is defined, as well as the instantaneous "dead state" of the composite and each subsystem.
Some pedagogical, scientific and engineering implications are discussed.