Abd ul-Rahman Lomax wrote: But the possibility would remain that some condition in the electrolyte > close to the cathode raises the resistance there, so the Joule heat would be > dissipated there, thus making the cathode appear hotter. But I think it > unlikely. Shanahan might disagree.
It does not matter how hot the cathode appears to be (how high the temperature is). It matters only how much heat the cell as a whole produces over time, and whether that heat exceeds input power by a large margin. Shanahan believes there are "positional" errors; i.e., the heat is shifted from one place in the cell to another and this causes an artifact in the calorimetry. With a calorimeter that measures heat in the electrolyte this is conceivable although it can easily be shown that it does not happen. With calorimeters that measure heat outside the cell it is impossible. Or nearly impossible. Storms has reported very slight positional variations with a Seebeck calorimeter so he uses a fan inside the calorimeter to stir the air and eliminate this. With other external types such as Miles' with the copper sleeve around the entire cell, I cannot imagine how there could be positional problems. How would you prevent copper from conducting the heat evenly to all 3 or 4 thermocouples, which are outside the sleeve? As far as I know, even in principle there is no way to tell where, inside the cell, the heat is originating. It might be handy if you could tell, but you cannot. The other day I mentioned to Shanahan that it seems unlikely this positional artifact would occur only with Pd and deuterium, and not Pt and hydrogen or Pd and hydrogen. He said that is not unlikely and his theory can account for it. I cannot imagine how changing the hydrogen isotope would produce positional problems, but that's what he said. > Absolutely. Heat is a signature, a crucial one. So how do we know we have > excess heat? Calorimetry? Fine. Problem for my purposes is that is > cumbersome. Yes, well, nature did not deign to make this experiment easy or convenient. That's rather like thinking about airplanes circa 1900 and saying "the problem for my purposes is that trying to fly is dangerous." It sure is! You should stay on the ground. - Jed
