On Sun, Jul 17, 2011 at 1:26 PM, Abd ul-Rahman Lomax <[email protected]>wrote:
> At 03:27 AM 7/17/2011, Damon Craig wrote: > >> Uhhh. I give up. How is a kink in a thermal curve evidence of exothermic >> activity? >> > > It's unclear what Damon is responding to. However, a change in the slope of > a heating curve will generally indicate some variation in condition, such as > changed input power or locally generated power. It's a rough calorimetric > technique, to determine what slope corresponds to what immediate power. > I agree. The slope depends on the input power and the thermal mass of the device. A doubling of the slope would correspond to twice the power. > If it were known that input power was constant, a sudden change in slope > could indicate additional power being applied. It is thus "evidence." But it > is certainly not proof, because that shift could be a result of something > else, such as a suddenly decreased coolant flow rate. > I don't think that's right. Since the water is flowing, it is not part of the thermal mass, which consists of the ecat and the infrastructure around it. So the rate of increase in temperature of the thermal mass would not be significantly affected by the flow rate. However, a sudden change in flow rate would produce a sudden change in the temperature of the output water. So, I think what you'd see is a vertical step in the temperature plot (during the heating up phase), and then continued increase with the same (or very similar) slope. > Remarkably, the Kullander and Essen data shows this phenomenon, with > apparent power doubling or tripling as the coolant temperature passed sixty > degrees. This apparent power is much lower than what was asserted from > overall heating on the assumption of full vaporization, Agreed. Full vaporization must assume another very much larger increase in the ecat power. Also, as you've pointed out before, the linear (not saturating) behaviour of the temperature before 60C suggests the power was higher than claimed, or the flow rate was lower than claimed. Basically, the data is not consistent.
