Rankine Cycle Performance Trends Effect of superheat on performance: .Purpose: Increase average temperature for heat addition at a given boiler pressure T increase in performance Increase in Wnet superheat T3 is limited by TH and materials TB Question: Why not increase Te instead? Answer: Need high steam quality at turbine outlet to avoid corrosion (want x4>0.9,better 0.95) -Would require higher boiler pressure materials,safety 上降文通大学 May9,2019 3 SHANGHAI JIAO TONG UNIVERSITYMay 9, 2019 3 Rankine Cycle Performance Trends Effect of superheat on performance: • Purpose: Increase average temperature for heat addition at a given boiler pressure increase in performance T3 is limited by TH and materials Question: Why not increase TB instead? Answer: - Need high steam quality at turbine outlet to avoid corrosion (want x4 > 0.9, better > 0.95) - Would require higher boiler pressure  materials, safety TB superheat