On Thu, Jun 23, 2011 at 7:26 PM, Abd ul-Rahman Lomax <[email protected]>wrote: > > It's flowing water, not a kettle. So the input power can only heat it so >> much. >> > > Depends on the flow rate, eh? Look, from the output temperature readings, > water is being raised to the boiling point, it's highly likely that some of > it is boiling, eh?
Of course it depends on the flow rate. And yes, some of it is boiling. The claim that you disagreed with is that the input power as claimed (300 W) is enough to bring the flowing water to the boiling point at the claimed flow rate (1.73 g/s). This is not possible, as E&K said. > Power in = mass-flow-rate * specific heat * temperature difference >> >> So, >> >> temperature difference = 300W / (1.73 g/s * 4.2 J/K g) = 41 K >> >> If the input temperature is 20C, then the maximum output is 61C. If you >> accept the numbers as given. >> > > So, are you convinced that the reactor is putting out energy? Otherwise > what is taking this to 100 C? I already addressed this. Yes, if those numbers are right, then the reactor is putting out energy. But only 300W are necessary to reach boiling, which does not so obviously exclude chemical heat as does the 4 kW that E&K claimed. I also pointed out that the input power was not monitored, and I would not put it past Rossi to increase the power (or reduce the flow) when his subjects were distracted. After all, he sort of got caught red-handed (well maybe only pink-handed) in the Lewan video, and it's pretty clear that the claims of flow-rate and experiment duration in the Jan demonstration were both blatantly wrong by about a factor of 2. I simply have no confidence in him at all. > > It's not like a kettle. The reason the graph shows a gradual increase in >> the temperature when the power is first applied, is that the reactor has to >> heat up first, and that absorbs some of the power. When it reaches >> equilibrium temperature, all the power goes in to heating the water. >> > > That's strange. I'd think that it all starts at the same temperature, Right. > and would rise in temperature more or less evently, What does this mean. The water is flowing through. only the water in the system gets heated. The input water will be at 20C, and the water at the output would almost certainly be cooler than the reactor. > except that the reactor core itself, which is directly being heated, would > get hotter than boiling It would be hotter than the output water throughout the heating, except at the starting point. > > If the only heating is from the element in the core, and that's constant, > all those temperatures would rise at some rate, All which temperatures. I really don't know what you're getting at. When you turn on the power, the conduit through which the water flows begins to warm up. And it in turn warms the water as it passes through. The water enters at 20C (say), but it probably doesn't reach the temperature of the conduit before it leaves. It's not long enough for that. So, when the conduit (reactor walls) is at 80C say, the water may come out at 40C. Then, maybe when the reactor reaches 150C, say, the water may come out at 60C. (Just examples.) Now, when the water comes out at 60C, it is removing 300W from the reactor. If the input power is 300W, then it won't get any hotter. The reactor will stay at 150C, and the output water will stay at 60C. The temperature of the water can be increased by increasing the power to the reactor (by chemical or nuclear processes), by increasing the electrical power, or by reducing the flow rate. In the chart of temperature, a sudden change in rate of temperature rise > appears, at 60 degrees C. I assume that this represents the time when the > core reached turn-on temperature. > Something certainly happens there. It could be a reaction (chemical or nuclear) initiated in the reactor. It is consistent with an increase in the input electrical power. (It's not consistent with a sudden reduction of flow rate, because that would produce a step change in the temperature, not just a change in the gradient.) > > There are lots-o-mysteries here. The original point was that the thing > shows no sign of settling at 60 degrees without excess heat, it was rising > linearly to that point. That's true. And that suggests that the power going to the reactor (from wherever) was already greater than 300W (or there would be an indication of saturation), or that the flow rate was lower than claimed. > The only place where there would be rapid alternation of the rate of change > of temperature would be where the water starts boiling, which would start to > draw off far more heat than the flowing water would remove. > I don't see this. The amount of heat transfer to the water would not change discontinuously at the boiling point. Why would it? If the temperature of the reactor continues to increase after the bp is reached, then it would transfer more heat to the water, and exactly enough of the water would change phase to absorb that additional heat. It would have to increase in temperature difference almost 7-fold to cause all of the water to boil. That has to take time. And more than 3 minutes as claimed by E&K. If, as you seem to suggest, when the boiling starts, and it takes more heat away to cause the temperature of the reactor to decrease, then immediately the transfer of heat would slow down, and the boiling would stop. There should be no sudden change of temperature.
