David Roberson <dlrober...@aol.com> wrote: Jed, looking at figure 6, the Oct 21 data I calculate that the average > power is 1.3888 watts. That is 20 watts * 500 seconds / 7200 seconds = > 1.3888 watts.
Yes, that is the answer I got, in Table 1. However, bear in mind that is for the water alone. Not for the reactor, which has a slightly larger thermal mass than the water, and much worse insulation. Estimating that, I get 3.4 W total, on average. Based on a very rough estimate of unaccounted for heat losses and Newton's law of cooling I guess the actual average power is about 7 W. In other words, the reactor metal plus the water are recovering about half of the heat. > If Mizuno applies that amount of power continuously what would you > expect the temperature to do? With 1.3 W input I expect to see nothing, as I said in the paper on p. 9. That is, in fact, what I saw when I did a similar test. There is too much noise, and the water recovers only about one-fourth of the heat, as I said. So I figure you would have to input ~7 W continuously to see this temperature rise. Mizuno hopes to do that kind of simulation but I do not know when. Actually, now that ambient fluctuations are reduced, you might see 1.3 W in the reactor. That would put ~0.5 W into the water I guess, about twice as much as the pump. It might raise the water temperature by ~1 deg C after an hour or two. It is hard to say. The only way to find out is to do a test and measure it. > My gut feeling is that the temperature would increase along a constant > slope once the transients are settled down. Well, it increases for a while, but at low power it then soon stops rising as the calorimeter goes from being adiabatic to isoperibolic. That takes 1.4 hours at ~0.2 W. I do not know how long it takes at 0.5 W or 3 W. At any power level it must eventually stop heating, when losses equal input power. Losses increase with the rising temperature, per Newton's law. > Also, can you verify that the water flow rate is actually nominally 8 > liters per minute? That's what Mizuno said. I suppose he measured it when dumping out the cooling water. He had to change out the Dewar reservoir a couple of times. I think that is what the pump spec. sheet says. There is hardly any resistance, and no grade, so I guess it should be close to maximum performance. - Jed
