rankine cycle vs carnot, vapor cycles
In reference to a system such as a steam power plant, I understand that the Rankine cycle is the most feasible cycle to consider. But, in looking in my text book, it's comparing the carnot vapor cycle to the rankine and I'm confused as to why the carnot cycle is constrained within the limits of the saturation curve. Obviously, thermal efficiency increases whenever you can increase the gap between Tmax and Tmin, but if Tmax is located outside saturation, as a superheated vapor.. you can't take this Tmax into consideration with the carnot vapor cycle, correct? In other words, I know I can calculate the thermal efficiency of a rev. carnot heat engine between a max temp and a min temp, but if these temperatures are outside of the saturation curve, can the carnot cycle still be applied? If the Carnot cycle IS only constrained within the saturation dome, why is this? Is it because isothermal conditions only exist within the saturation dome?
Again, I'm new to the forum and I appreciate all input. Also, if I have posted in the wrong area, please let me know and I will figure out how to move it.
Thanks.