I still think that the 2-chamber design explains more than the 1-chamber 3-bar design. The core could easily be engineered with a water-efficient heat exchanger in one chamber, and a steam-efficient heat exchanger in the other.
From Lewan's report :
> According to Andrea Rossi the increased dimension is due to a larger volume inside where the water is heated, approximately 30 liters, and a larger heat-exchanger with a greater surface which should result in a more effective heat transfer from the reactor to the circulating water and also in additional heating of the steam after vaporization.
> additional heating of the steam after vaporization
That's super-heating.
So to confirm Rossi's statements (130C, 1 Bar Pressure, No restrictor orifice, No direct fluid overflow) we would need to show that 130C (or maybe 120C) superheated steam (ie NO liquid water) at 11 kg/hr will condense to 50% fluid water in a 10cm long x 0.5cm radius rubber tube.