Process 1-2 Isentropic expansion from vapor to a saturated mixture .
Process 2-3 Heat transfer out at constant pressure
Process 3-4 Isentropic compression to a compressed liquid
Process 4-1 Heat transfer in at a constant pressure
$$ \eta=\frac{W}{Q_H}=\frac{(h_1-h_2)-(h_4-h_3)}{h_1-h_4} $$
$$ \eta_t=\frac{h_1-h_2}{h_1-h_{2s}} $$
$$ \eta_p=\frac{h_{2s}-h_1}{h_2-h_1} $$
The efficiency of a Rankine cycle can be improved by heating the steam further, increasing the boiler pressure, and lowering the condensers pressure. These all increase the average temperature. An additional process of heating placed between the turbines can also be effective.
$$ bwr=\frac{W_p}{W_t}=\frac{h_4-h_3}{h_1-h_2} $$