A Rankine cycle with regeneration has steam enter a turbine at 30 bars and 500 degrees C. The condenser pressure is 0.1 bar. A single open feedwater heater is employed which operates at 5 bars. The isentropic efficiency of the turbine is 82% and both pump efficiencies are 78%. Determine
a) thermal efficiency of the cycle
b) mass flow rate of steam required to produce 100 MW of net power
c) heat transfer rate from the condenser
Another thermo text states that the optimum temperature at state 1 should be close to halfway between the saturation temperatures of the turbine inlet state and the condenser exit state. In this case Tsat(30 bars) = 234 degrees C and Tsat(0.1 bar) = 46 degrees C. Thus the average is 140 degrees C. The saturation pressure corresponding to this temperature is close to 3.6 bars. Recalculate the efficiency of for an extraction pressure of 3.5 bars.