OK, vorticians. This is could be an important paper and topic, so let me add one more point of clarification to Michel Jullian's point about the "heat of combustion" of hydrogen, compared to the anomalous "loading heat" of Kitamura's claim.
Michel correctly finds that if you only look at one-half of the reaction, and ignore the mass of the end product, then what we have is: (294.6 / 2) / 6.02e23) * kJ = ~1.5 electron volts/amu based on hydrogen This is the energy released relative to initial hydrogen mass, but that might assume that oxygen is unnecessary, if you leave it out. One should take the mass of O2 into consideration for the comparison with reversible hydride loading. ERGO. It would have been clearer back a few posts ago - if I had broken the comparison down this way. The steam from hydrogen combustion will have a molecular wt of 18 amu per hot molecule. The heat of combustion of the two hydrogen atoms is ~3+ eV in total. The resultant energy per amu of the steam, therefore, is 3/18 or .16 eV per amu of combustion end product. When we compare that energy per mass of combustion product - with the Kitamura reaction of hydrogen which has been reversibly loaded into a metal matrix, and then released, then we find that the amu of the end product is still about one since there is/was no permanent bond. The thermal energy released, according to Kitamura is ~2 eV, so the eV per amu is about a *ten to one ratio,* when the energy of the hydride bond is deducted - compared to hydrogen combustion (by mass of all non-renewable reactants). Next big issue. What is the "real" hydride bond energy for Pd? There is a chart here (Fig 3): http://www.iop.org/EJ/article/1742-6596/79/1/012028/jpconf7_79_012028.pdf?re quest-id=e4195775-a6d5-4d5f-83b9-da98912aa8c1 It appears that the bond energy for Pd varies between .9 eV and a negative value, depending of a number of variables. The bond is field influenced, which could be important. From the chart - an average value appears to be less than .5 eV. However, the indication is that it could be much lower. Therefore, if Kitamura were correct on the heat energy (which I am beginning to doubt), then this kind of iterative recycling of hydrogen would be a window of opportunity for gainfulness, since the spread is very large. This is too simple and robust to be real, no? This looks like a COP of close to three. For an accurate cross-comparison based on all reactants - it is fair to say that we are looking an initial gain of almost ten to one over combustion; moreover it is an infinite gain if based on the renewability of the hydrogen, that is: if the COP~3 allows that to happen, after the conversion losses of heat back into electricity. Before we can arrive at an accurate final appraisal for the usefulness of the process, we must consider the net energy necessary to release the hydrogen from the matrix. If that were to be .5 eV as the IOP paper suggests (or less with an electric field) - then there is a huge potential for net gain from recycling the hydrogen. "IF" of course, Kitamura got the 2 eV thermal number correct. Doubts remain on that issue. The big "if." Jones
