Continue Rankine Cycle Performance Trends Continue effect of boiler pressure on performance: .Assume:TC=66C [pc=Psat(Tc)=0.255 bar] x4=0.95 [specifies T3] TB(C) PB(bar) T3(C) 7 232 29 400 0.246 288 72 506 0.290 343 153 604 0.324 Notes: T3 increases faster than TBoiling to maintain X4 maximum pressure dictated by temperature of heat source and materials . optimal pressure:trade-off between 1st costs and operating costs 上游充通大 May9,2018 6
May 9, 2018 6 Continue Rankine Cycle Performance Trends Continue effect of boiler pressure on performance: • Assume: TC = 66 oC [ p C = psat ( TC) = 0.255 bar] x 4 = 0.95 [specifies T3] TB ( oC) p B (bar) T3 ( oC) 232 29 400 0.246 288 72 506 0.290 343 153 604 0.324 Notes: • T3 increases faster than TBoiling to maintain x 4 • maximum pressure dictated by temperature of heat source and materials • optimal pressure: trade‐off between 1st costs and operating costs
Continue Rankine Cycle Performance Trends Effect of condensing pressure on performance: Lower condenser pressure increase work output at the same heat input >Increase in efficiency -Lower limit depends on environmental temperature P4<P Lowering pressure Increase in Wnet decreases quality →Must increase T3to keep quality constant S 上游充通大率 May9,2018 7 SHANGHA BAO TONG LINIERSITY
May 9, 2018 7 Continue Rankine Cycle Performance Trends Effect of condensing pressure on performance: ‐ Lower condenser pressure increase work output at the same heat input Increase in efficiency ‐Lower limit depends on environmental temperature ‐ Lowering pressure decreases quality Must increase T3 to keep quality constant