Solution (cont.)

(a) The thermal efficiency h = 1-qout/qin= 1-1672.6/2586.5=0.353=35.3%

(b) Net work output dW/dt=50MW=(dm/dt)(Wout-Win)=(dm/dt)((h3-h4)-(h2-h1))

mass flow rate (dm/dt)=50000/((2784.3- 1864.4 )-(197.85-191.8))=54.7(kg/s)

( c) heat transfer into the boiler qin = (dm/dt)(h3-h2)=54.7(2586.5)=141.5(MW)

(d) Inside the condenser, the cooling water is being heated from the heat transfered from the condensing steam.

q cooling water = qout = (dm/dt)(h4-h1) = 54.7(1672.6) = 91.49 (MW)

(dm/dt)cooling water Cp (Tout - Tin) = q cooling water

C p, water = 4.177(kJ/kg K)

(dm/dt)cooling water = 91490/(4.177*(40-20)) = 1095.2 (kg/s)

?Very large amount of cooling water is needed ?