Did you know that the Enthalpy of a subcooled liquid is the same as the Enthalpy for that liquid at saturation conditions?
Yep.
Now, once sensible heat has been added and the liquid's temperature has been raised to saturation conditions, any additional heat addition will be latent heat and will raise the Enthalpy of the fluid instead of the temperature of the fluid.
That's why we have steam tables. There's a lot going on during the addition of latent heat in the phase change process and it's worth studying.
This is especially true in Boiling Water Reactors (BWRs) where two-phase flow and saturation conditions are ideal for removing heat from the fuel rods.
BWRs are an artful balance of making sure there's enough boiling while not over-boiling. We want to make sure the fuel is protected and not damaged while making sure the steam is dry enough to not damage the turbine. We have to make sure there is enough suction head (pressure) for the recirculation pumps so that they don't cavitate with the high temperatures and flows we operate them at.
But, back to subcooled liquids.
In this video, I show you how to solve a simple "How subcooled is the liquid" problem: