So, how does this compare to the recombination energy of atomic hydrogen? Here's a reference by a dubious source:
http://www.cheniere.org/misc/a_h%20reaction.htm :-) Terry On Tue, Dec 29, 2009 at 4:04 PM, Jones Beene <jone...@pacbell.net> wrote: > 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 > > > >
