Real vapor-power plants modify the simple Rankine cycle to improve efficiency and control turbine-exit moisture.

Superheating raises turbine-inlet temperature above saturation, usually increasing turbine work and reducing moisture at the outlet.

Reheat expands vapor through part of the turbine, returns it to a reheater, and then expands it again. This increases average heat-addition temperature and keeps later turbine stages drier.

Regeneration extracts some steam from intermediate turbine stages to preheat feedwater, the liquid working fluid being returned toward the boiler. This reduces external heat input by raising the average temperature at which heat is supplied.

These modifications trade simplicity, equipment cost and sometimes net work against thermal efficiency and component constraints.

Their common thermodynamic purpose is to make heat addition occur at a higher effective temperature, heat rejection occur at a lower effective temperature, or expansion proceed with less damaging moisture while preserving the same mass and energy balances.