Jones Beene <jone...@pacbell.net> wrote: > Was a long blank run done with no other power into the system other than > the pump? > Yes. As I noted, with the previous configuration Mizuno did this on purpose. With this configuration he did it by accident, as shown in Fig. 14.
With the previous configuration, Mizuno left the pump running for a full day by itself. The water temperature never rose significantly above ambient. That was with less insulation so the system cooled faster, so the difference caused by heat from the water stirring would have made a smaller temperature difference. However, even with that configuration he could measure a fraction of a watt, and he did not see it. So that puts an upper bound on heat from stirring. Figure 14 shows the pump went off in the middle of the night in the Oct. 21 dataset. So any heating from the pump is eliminated. You can download data for Oct. 21 and 22 and compare the cooling rates. For Oct 21, you need to take into account the separate thermal masses of the reactor and Dewar. The Dewar has 3 kg of water, and the reactor has 50.5 kg of stainless steel plus ~1 kg of water in the tube. Ambient falls a little less on Oct. 21. This gets complicated. Anyway, if you do the numbers carefully you will see that the pump makes no measurable difference. Of course it is better to do this test on purpose. It will be better still when ambient fluctuations are reduced with a new heating and air conditioning system, which we hope will be installed soon. > > On eBay for instance, 8 liter/min Lab pumps are found and most are in > the 80 watt range. Given that water pumps are efficient, much of that > expended power gets dumped into the system in the form of heat. This > needs to be accounted for in baseline calibration. Maybe I missed it. > You missed it because I mentioned this briefly in two places. Mizuno and I discussed this at length but I only touched on it here because . . . I saw the paper was 25 pages long already with no end in sight! Obviously, the pump has to add some heat, but not enough to measure with this system. - Jed
