- "Available energy" redirects here. For the meaning of the term in particle collisions, see Available energy (particle collision).
In
thermodynamics, the
exergy of a
system is the maximum useful
work possible during a
process that brings the system into
equilibrium with a
heat reservoir. When the
surroundings are the reservoir, exergy is the potential of a system to cause a change as it achieves equilibrium with its environment. Exergy is the
energy that is available to be used. After the system and surroundings reach equilibrium, the exergy is zero. Determining exergy was also the first goal of
thermodynamics. The term "exergy" was coined in 1956 by
Zoran Rant (1904–1972) by using the Greek and meaning "from
work", but the concept was developed by
J. Willard Gibbs in 1873.
