Maybe you have an error with your simulation since the number does not seem to match the real world results. What kind of flow did you assume in the primary? I think that vapor condensation is where the most action is since that takes so much more energy than cooling the hot condensed liquid. I wish someone would have been wise enough to place the thermocouple well.
My initial simulation assumes primary 100C water IN at 15 L / hour, and the secondary 30C water leaving the heat exchanger at 600 L / hour.
The "height" of my manifold model is approximately right, but it's probably 1/2 the correct length.
I plan to calibrate the water/water simulation and then consider steam/water.
The manifold is so short that I don't think there would be significant condensation in it -- so the heat transfer will be the same for superheated or saturated (100% dry) steam.
