The effect of a number of open FWHs on the thermal efficiency of an ideal cycle is to be studied. Steam leaves the steam generator at 20 MPa, 600?C, and the cycle has a condenser pressure of 10 kPa. Determine the thermal efficiency for each of the following cases:
(a) no FWH,
(b) one FWH operating at 1 MPa, and
(c) two FWHs, one operating at 3 MPa and the other at 0.2 MPa.