Natural circulation problem

Hello, Community.

I have a question connected with hydrodynamics and natural circulation.

As you know, in such systems water changes its state to steam and moving upwards the pipe without pumps.

You can see the photo of the system in my post.

The problem is in water tank(water is in normal condition) which is located higher.

There is a system of 140 tubes inside; it is not so easy to find an equation which will show where the steam(temperature is about 202 degrees,16 bars) becomes water during the process of condensation(i.e temperature distributions in pipes). Pipe pattern is not so important.

In addition, defining the preferences of water in downward pipe is complicated either.

If you have an experience with such problems (maybe even templates), I will appreciate your help.

Thank you for the attention!