On Mon, May 9, 2011 at 4:43 PM, OrionWorks - Steven V Johnson < svj.orionwo...@gmail.com> wrote:
> Let me add my two cents: > Sorry, it's not worth even that. (I've stayed away from this list because its terms of reference clearly exclude people of my mindset, but this discussion of higher temperatures of steam originated (several months back) from a post of mine that was cross-posted here, and I feel compelled to defend it, and to correct the sort of elementary, mistaken ideas people here seem to have. I will refrain this time from entering any discussion not directly related to this topic.) > > If Rossi's e-Cat reactor core can regularly sustain temperatures of > 500c or higher, water that is in contact with the reactor core's > surface FOR LONG ENOUGH PERIODS will most certainly exceed > temperatures 100.1 C, and by quite a large margin. > This is quite true. But the question is simply what are long enough periods? It turns out that the distance is more relevant than the time, because heat transfer coefficients are given as power transferred per unit area per unit temperature difference. And the coefficient for steam/copper is slightly *higher* than it is for water/copper. > > However, the tick would be to keep the water that has just been > transformed into steam contained long enough AT the e-cat reactor > core's surface so that it has the chance to absorb the additional > heat. Currently this doesn't happen. All you know is that the steam is not heated above the boiling point. But that is what would happen if there were still liquid present. What would happen if the water were all converted to steam before the end of the reactor, say because the flow rate were reduced, as suggested at the beginning of this thread. Say the water is all converted to steam within the first 90% of the reactor. Then amount of heat transferred to the steam will about 10% of what was transferred to the water. Let's see: 10% of 540 cal/g (to produce steam) is 54 cal/g. Since the specific heat of steam is about 0.5, that gives about 100C increase in the temperature of the steam. So you see, if all the water were converted to steam, keeping it at 100C would be extremely difficult indeed. There is no doubt at all that the temperature indicates the presence of some liquid water. This can be argued another way as well, which doesn't require any knowledge of heat transfer coefficients. If the flow rate were reduced, and there weren't enough time to heat the steam, then the additional power would cause the reactor to get hotter. And that would cause the water to boil earlier, giving the steam more time to get hotter. A new equilibrium would be reached, but at a lower flow rate, the only ways to remove the same amount of thermal power would be for the steam to get hotter, or for more heat to leak through the insulation, and the insulation would have to get extremely hot to dissipate power in the range of kW. > It's my understanding that the > current Rossi prototypes (perhaps for demonstration purposes) do not > appear to be built in such a way as to physically contain the > transformed steam. It's not designed to behave like a pressure > cooker! For heaven's sake. Please get this notion that higher pressure is needed to heat steam above the boiling point out of your heads. Your furnace has no trouble heating air to about 220C above its boiling point at atmospheric pressure. Have you never looked at a phase diagram? The reason a pressure cooker needs pressure is because _there is still water present_ in a pressure cooker, and it is only the water that is heated directly; not the steam. In an ecat, after the water has boiled, the steam would be heated directly, and just as efficiently per unit area as water. It does not have to "contain" the steam any more than your furnace has to contain air as it circulates it past the hot surfaces. The water immediately after it has been transformed into steam > quickly expands. The steam quickly shoots out the exhaust pipe - i.e. > the infamous black hose. IOW, the steam doesn't have a chance to hang > around long enough to absorb additional heat and subsequently increase > in temperature much above 100.1 C. > Again, this is completely wrong. Steam is much less dense, but the molecules move much faster and therefore collide more often with the walls, the net effect being that it is *more*, not less effective at absorbing heat per unit area than liquid water. (Of course as the steam gets hotter, its effectiveness gets lower.) > Some on this list may still recall several months ago the fact that > there was a protracted argument precisely based on this specific steam > temperature issue. Some argued: WHY was the steam only measured to be > 100.1 C when it exited out of the black hose, especially if the e-Cat > reactor was claimed to be hundreds of degrees higher. Because the > exiting steam temperature seemed to be rigidly fixed at 100.1 C some > on this list became absolutely convinced Rossi was involved in a scam > operation. No, but rigidly convinced that the steam was wet. Still are. > However further experiments have proven that such concerns > appear to be groundless, particularly (and ironically) when > experimenters increased the water flow to show a simple 5 degree > temperature increase. (More accurate calometric measurements > resulted.) That's more nonsense. The additional experiment, with exactly one witness, if taken at face value, proved that the instrument could produce 15 - 20 kW (or something like that). It did not prove that the steam in the January demonstration was dry. In fact the frequent excursions of that instrument well above 12 kW suggests that the steam should have frequently exceeded the boiling point by at least 100C in the January demo. So there appears to be a contradiction there. What makes that private experiment even harder to take seriously is the claimed 130 kW excursion. Rossi has on occasion mentioned an optimum operating temperature of about 400C. If this temperature provides the usual 15 - 20 kW, then 130 kW would require a temperature difference about 9 times higher; for water temperature of 30C say, that would correspond to 370*9 + 30 = 3360C, which is not plausible. I don't quite see how the 18-hour experiment can be treated as vindication anyway. Imagine a salesman comes to a town selling a device that converts lead into gold, but it has to be seeded with some gold to start with. The output is some molten mixture of the two, but the townspeople claim there is no more gold in the mixture than was put in, and no one seems to have the technology to separate them. A week later they come back and say it's ok because back in their laboratory they produced pure gold. Would you buy their device from them based on that evidence? > > IOW, I doubt Rossi's e-cats, if engineered properly, would have a > problem raising steam to significantly higher temperatures than 100.1 > C. > > Gee, it's shame he's not an engineer…
