Derivation of exergy balance equation for CV sys. Useful Work: Solving for work term,and rearranging combining: 咸-yn〔n+分+---+g-r Some of the work may be done by or against the atmosphere and is not useful: tWc=Wct-P。 dVcv dt The definition of useful work is then, wh++g-T-m++g-t 2 ou out destruction -} dEcy-p。 dt Ney+T。dt dScv of exergy due to irreversibilities within dt the system. 上游充通大学 May2,2018 4 SHANGHAI JIAO TONG UNIVERSITYMay 2, 2018 4 Derivation of exergy balance equation for CV sys. Solving for work term, and rearranging & combining: Some of the work may be done by or against the atmosphere and is not useful: The definition of useful work is then, 2 2 act in o out o in out in out o CV CV j o o tot j j v v W m h gz T s m h gz T s 2 2 T dE dS Q 1 T T T dt dt                                    CV use act o dV W W p dt   Useful Work: 2 2 use in o out o in out in out o CV CV CV j o o o tot j j v v W m h gz T s m h gz T s 2 2 T dE dV dS Q 1 p T T T dt dt dt                                       destruction of exergy due to irreversibilities within the system