Modeling preheating evaporator with Dymola (idea from thermal power Library)

Question

I'd like to discuss the modeling idea of preheating evaporator (similar to shell and tube heat exchanger, molten salt on the tube side and water on the shell side). There are two key points,

1. The shell side has a certain volume retardation, similar to volumedynamics;

2 is the thermal inertia of heat transfer, and the existence of heat capacity will also affect the dynamic characteristics;

The above is my modeling idea. Welcome to discuss the better modeling idea of "preheating evaporator".

Finally, I have a little question and hope to get your suggestions:

Calculation of heat transfer coefficient of water at shell side (including boiling);