Effects of boiler and condense pressure -Fixed boiler pressure Increased boiler pressure Decreased condenser pressure Fixed Patm condenser pressure 100°C (212°F) p<Patm Ambient temperature 下、 Lowest pressure Boiler pressure个 Condenser pressure↓ Higher average heating TH Lower average condensing Tc =1、 Thermal efficiency↑ Thermal efficiency T 上游充通大 Wednesday,April 26,2017 11 SHANGHAI JIAO TONG UNIVERSITY
Wednesday, April 26, 2017 11 Effects of boiler and condense pressure Higher average heating TH Lower average condensing TC Boiler pressure ↑ Condenser pressure ↓ Thermal efficiency ↑ Thermal efficiency ↑ Lowest pressure C th,equiv.C H T 1 T
Irreversibility and losses Turbine and pump: Boiler and Condenser: Internal irreversibilities 2s2 iler 1 Isentropic turbine efficiency Heat transfer:external irreversibility 习 (W/ri) h1-h2 dominant 7:= (W/m)、h1-h2s Isentropic pump efficiency 之out (W/m、 has -h3 Cooling water (Wp/mt) h4-h3 Condenser 上泽通大学 Wednesday,April 26,2017 12 SHANGHAI JIAO TONG UNIVERSITY
Wednesday, April 26, 2017 12 Irreversibility and losses Turbine and pump: Isentropic turbine efficiency Isentropic pump efficiency Internal irreversibilities Heat transfer: external irreversibility dominant Boiler and Condenser: