Find the second-law efficiency for the closed FWH in Problem 9.51.
Problem 9.51
A closed FWH in a regenerative steam power cycle heats 20 kg/s of water from 100?C, 20 MPa to 200?C, 20 MPa. The extraction steam from the turbine enters the heater at 4 MPa, 275?C and leaves as saturated liquid. What is the required mass flow rate of the extraction steam?