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 Question: Why not increase Tg 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 上游充通大￥ May9,2018 3 SHANGHA BAO TONG LINIERSITYMay 9, 2018 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 T 3 is limited by T H and materials Question: Why not increase T B instead? Answer: ‐ Need high steam quality at turbine outlet to avoid corrosion (want x 4 > 0.9, better > 0.95) ‐ Would require higher boiler pressure  materials, safety T B superheat