Below is a follow up posting at the web site. As far as I can tell, this would apply to Heffner's calculation as well. Assuming the frying pan makes 1% wet steam, it should have taken about 4 minutes for all of the water to leave the pan, by his calculation.
I do not think my frying pan is inherently superior to the Rossi device and likely to make much drier steam. - - - - - - - - - - - - - - - - - - Let me add that I have done this test with much better equipment: a well insulated vessel with a submerged joule heater. The recovery rate was much higher. In that test, the steam was quite wet, with entrained droplets of water that fell onto the tissue placed next to the vessel. Yet the overall value was close to the textbook heat of vaporization of water. Guest asserts that it is possible to generate very wet steam with 700 W where dry steam would take 12,000 W, a factor of 17 less. The tests I performed and the formulas at http://www.engineeringtoolbox.com/wet-steam-quality-d_426.html prove this is not the case. Given the flow rate during the Rossi device tests, 700 W would not even be enough to heat the water to boiling. Whatever the dryness of the steam from the Rossi device may be, I am sure that my frying pan is no dryer, so if it is possible to appear to generate steam with 17 times less energy than the textbooks indicate, all of the water in the frying pan would have been gone in 1.2 minutes, instead of 20 minutes.
