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Nji Gerald Nde

Difference between Gibbs Free Energy and Exergy

Bob Spencer  Follow

Exergy is equal to the Gibbs free energy if you happen to be in the isothermal--isobaric ensemble $(N, P, T)$, i.e. in a closed system if the pressure $P$ and temperature $T$ are constant. This is indicated in Eq. 7 of the Wikipedia page for exergy.

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Douglas Klein  Follow
Thanks for your precise and clear answer. So Exergy is a way to "call" the free energies depending on the process considered (constant volume-->Helmholtz free energy, constant pressure-->Gibbs free energy)? For example if I considered a stream of hot gas, the maximum work that can be extracted, i.e. its exergy, is the Gibbs free energy if I assume to be at constant pressure?More
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Glen Broderick  Follow
exergyMore
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Ernest Carrott Junior  Follow
… Although it has some historical relevance, I am not sure how useful it is in a modern presentation of statistical thermodynamics.More
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Eric Bittner  Follow
I would add a personal note: Ive done thermodynamics (and taught it) for many years without ever using the concept of More
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Bryan Michaels-Lex  Follow

Gibbs free energy is calculated without possible PV-work, ie. without volume changes.

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