Lecture 7: Exergy AnalysisNote: All previous analyses considered the isentropic process as the goal to strive for.Maximize adiabatic and isentropic efficiencyThih ihti ht d fthThis approach is short sighted for three reasons:1.It ignores processes where heat transfer is present.(The majority of all practical processes.)2.It assumes that reversibility can be obtained:Not possible!3Itth t thitt tfdi“flt”3.It assumes that the exit state of a device can “float”, i.e., cases where the exit pressure is fixed, but the exit temperature is allowed to fall below the temperature of thdiN tibl !7.1the surroundings: Not possible!
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Continue Exergy AnalysisNeed different approach for thermodynamic analysis:Exergy AnalysisNotes:»It can be used for both adiabatic and non-adiabatic processes.»It shows how close a device operating between two fixed end states is to its optimum performance.» It identifies the system components most responsible for»It identifies the system components most responsible for sub-optimum system performance.7.2