Previous:energy analysis All considered the isentropic process as the goal to strive for. Maximize isentropic efficiency This 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. 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 the surroundings. >Need different approach for thermodynamic analysis: Exergy (Availability)Analysis 上游气通大 May2,2018 2 SHANGHAI JIAO TONG UNIVERSITYMay 2, 2018 2 Previous: energy analysis All considered the isentropic process as the goal to strive for. Maximize isentropic efficiency  This 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. 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 the surroundings. Need different approach for thermodynamic analysis: Exergy (Availability) Analysis