A economizer in a steam generator performs the function of

The layout of a steam power plant working on the Rankine Cycle with single stage regeneration is shown in figure. Assuming the exit stream from the re-generator to be saturated draw the corresponding ideal cycle on a Mollier Chart and derive an expression for the thermal efficiency of the cycle.

Boiler $$-$$ $$B$$
Feed water heater $$-R$$
Pump $$-P$$