On 01/18/2011 02:52 PM, Jed Rothwell wrote: > Stephen A. Lawrence wrote: > >> CLOSE THE LOOP. >> >> He [Rossi] says he can run without any electrical input. Ergo he >> /can/ close the loop, without the expense of a Stirling motor and >> generator. > > Actually, that is heat input, from an AC resistance heater. Presumably > it would work as well with combustion heating. He said he can run > without heat input, but it is dangerous. I do not think he elaborated > on that. I gather it means he uses heat to modulate the reaction. > > The Piantelli Ni experiments required high temperature and external > heating. > > I believe the control factors are heat and pressure. The H2 is at 2 > atm, according to Celani. When you depressurize the cell, the reaction > soon stops. That's good news. Cold fusion reactions are sometimes > nearly as difficult to stop as they are to start. > > I assume the Rossi device has some internal self-regulation, or what > Stan Pons called a "memory" that keeps electrochemical cells going > back to the same power level after you refill the cell, tap on it, or > disturb it some other way. I also assume there is something about the > Rossi device that acts analogously to a self-quenching CANDU nuclear > reactor. I am only speculating; I have no knowledge of this. The > mechanism would be something like the metal degassing at very high > temperature, cooling down, and then absorbing the gas and reacting > again. That would explain why it quickly stops when you degas > manually. I suspect the electric heater is in the core, and the cold > fusion reaction occurs in the Ni powder surrounding that. I recall > some of the Piantelli devices had heaters attached directly to the Ni bar. > > I think Rossi claimed the internal temperature of this thing is > 1500°C. Ed Storms pointed out that cannot be right, because the > melting point of Ni is 1,453°C. Perhaps that is a misunderstanding, or > a mistranslation. Still, it must be pretty hot in there because the > device is small and well insulated. Even with 400 W or 1000 W from the > AC heater it must be quite hot internally. I assume (but I do not > know) that the heater is the hottest part. That's how I imagine it works.
Actually, I'd expect the joule heater to be rather cool relative to the reactive elements once the thing gets rolling. The reaction is contributing 10 kW or more at that point; the joule heater is just plugging along at 400 watts. That, also, makes it seem a little surprising that the joule heater continues to be used *after* "ignition". It's contributing just 4% of the total heat; you'd think they could just shut it off after the thing starts up. Of course, the reacting surface area may be large enough that it stays cooler than the heater, and perhaps the intense heat near the heater wire has something to do with the reason they continue to use it after "ignition". Incidentally, a 1500 degree internal temperature also makes the use of unpressurized water for a coolant seem to me to be a little iffy. Perhaps that has something to do with the reason they boil it all to steam, rather than running the pump harder and getting out hot water (which, it has been suggested, might have provided a more rock-solid output heat measure). > > - Jed >
