Comments on Fleischmann and Pons paper.
morr...@vxprix.cern.ch
5th DRAFT - Scientific Comments Welcomed. 6 May 1993.
COMMENTS ON CLAIMS OF EXCESS ENTHALPY BY FLEISCHMANN AND PONS
USING SIMPLE CELLS MADE TO BOIL
Douglas R.O. Morrison.
M. Fleischmann and S. Pons [1] have published in Physics Letters A
a communication entitled "Calorimetry of the Pd-D2O system: from simplicity
via complications to simplicity". There they claim evidence for the production
of excess enthalpy of greater than one kW per cc of Palladium in a Pd-D2O
system. They comment that this is comparable with the rates obtained in a fast
breeder reactor. They note that the reproducibility is high. In this letter
serious doubts are expressed about this claim and the methods used to derive it.
Essentially they perform electrolysis in a transparent test tube which is
open so that the gases and vapour can escape freely. The cathode is a small
rod of palladium of 0.2 cm diameter and 1.25 cm length giving a total volume
of 0.039 cm3. There are three stages.
For the first stage a moderate current is used for electrolysis. It is
noted that at short times the heat transfer coefficient decreases - this they
ascribe to the heat of absorbtion of hydrogen ions in the lattice.
In the second stage the current densities are raised to increase the
temperature above 50 C - this with D2O. Finally, in stage three, the cells are
driven to boiling point. A complicated (non-linear regression) analysis [2]
is employed and it is calculated that there is excess enthalpy generated in
the lattice, the amount calculated increasing steeply with time (and
temperature).
In the third stage the behaviour near and during boiling is observed
using a video camera. From this video, the time for the cell to go from about
half-empty to dry, is taken - more precisely the amount of liquid boiled off
is estimated over the final 10 minutes before the test tube was declared dry.
A new simple calculation is made in which the enthalpy input is calculated as
(cell voltage - 1.54 V).(cell current)
and the enthalpy output is taken as composed of two terms, the energy radiated
and the heat resulting from the vapourization of the D2O remaining in the cell
600 seconds before it is dry (this latter term is dominant). It is this simple
calculation that gives the highest values claimed, namely "the excess rate of
energy production is about four times that of the enthalpy input" and that
the excess specific rate is 3.7 kW per cc of Palladium.
There are several major problems with this calculation.
First is that the "cigarette lighter effect" has been forgotten. In the
last century it was difficult to make reliable matches to light cigarettes.
A reliable smokeless lighter was invented which consisted of a rod of
palladium into which hydrogen had been introduced under pressure. This
caused the lattice of the palladium to expand and thus stored energy.
To light a cigarette, the top of the rod was uncovered; some hydrogen
escaped releasing some of the stress and thus releasing energy which
resulted in a small rise in temperature of the end of the rod. Palladium is a
catalyst of hydrogen and oxygen which burn to give water plus energy. The
palladium now slightly heated, catalyzes the escaping hydrogen and the oxygen
of the air and the resulting heat of combustion which is mainly deposited on
the surface of the rod, raises its temperature. This temperature rise releases
more hydrogen which is catalyzed by the still more efficient hot palladium,
and so on until the tip of the rod is so hot that the cigarette can be lit.
The reliability of this system is high.
In the simple calculation used for stage three, a significant effect is
omitted, of the heat produced by the catalytized recombination of the hydrogen
with the oxygen. The oxygen is released from the anode by electrolysis, and
towards the end when the cell is about dry, from the air. There is no mention
in Fleischmann and Pons's paper of any attempt to measure the amount of oxygen,
deuterium and water in the gases and vapours leaving the test tube.
In the Fleischmann and Pons paper, it is noted as a further demonstration
result, that "following the boiling to dryness and the open-circuiting
of the cells, the cells nevertheless remain at high temperature for
prolonged periods of time (fig.11); furthermore the Kel-F supports of
the electrodes at the base of the cells melt so that the local temperature
must exceed 300 C." This dramatic effect cannot be explained by Fleischmann
and Pons as being due to electrolysis since there is no liquid and
no electrolysis. However it is exactly what would be expected with the
"cigarette lighter effect" where the hot palladium rod continues to catalyze
the interaction of the hydrogen which is slowly escaping from the rod,
with oxygen from the air.
It might be expected that this effect would occur also with normal water,
H2O, being used instead of heavy water, D2O, but no description is given in the
paper of any results of tests of the stage three boiling using normal water,H2O.
An interesting confirmation of this using electrochemistry was reported
by Kreysa, Marx and Plieth [3]. They write "We have to report here that as we
removed the deuterium-loaded palladium sheet from the cell and laid it on the
table it did burn a scald into the table. One can still argue that this was
due to deuterium fusion. Therefore we loaded the palladium sheet cathodically
with hydrogen using an electrolyte containing only normal water (no enriched
heavy water) and laid it on to a piece of wood where it also burnt a scald."
They say it releases 147.3 kJ per mole D. "The principle of flameless
catalytic combustion of hydrogen" - the official name of the 'cigarette lighter
effect' - "is used in catalytic hydrogen burners (D. Behrens (ed)
Waserstoffetechnologie - Perspektiven fur Forschung und Entwicklung, Dechema,
Frankfurt/M 1986)." To be more quantitative they laid a hydrogen-loaded
sheet of palladium on to glass rods and "measured, after an incubation time
of 15 s, a temperature rise of the palladium from 20 to 418 degres within
74 seconds." The 15 second delay is the time during which the gradual escape of
hydrogen releases a small amount of energy from the lattice, thus heating the
palladium sufficiently for it to become an efficient catalyst. They estimate
a heat flow of 35.9 W and a heat flow density of 179.6 W/cm3".
It may be noted that Fleischmann and Pons used an exceedingly small piece
of palladium, 0.04 cm3, which works well as a catalyst, but which means that
after catalyzing a larger volume of heavy water, the power calculated is
apparently larger than with Kreysa et al. because the volume of palladium is
so small. Should Drs. Fleischmann and Pons wish to test their previous
conclusions [1], it would be interesting if they were to describe experiments
where they repeated their published experiment but with a substantially larger
amount of palladium and a relatively small volume of D2O.
Secondly, there is the assumption that ALL the liquid present in the tube
600 seconds before dryness, was boiled off. That is none of it was carried out
as a liquid, from the test tube. Now the video shows that there is highly
turbulent motion. And as Kreysa et al. [3] showed, 74 seconds after the
palladium becomes dry, temperatures of a few hundred degrees can be reached.
Thus it is reasonable to expect that with such a chaotic system, some fraction
of the liquid is blown out of the test tube as liquid and therefore should not
be counted. The existence of such a fraction is omitted from the simple
Fleischmann and Pons calculation. And no attempt to measure this fraction is
described.
Thirdly, the input enthalpy is taken as the current multiplied by the
(cell voltage - 1.54V). It is not explained how these quantities are measured.
This is crucial as when the cell is boiling vigorously, the impedance must
be fluctuating strongly. Thus the current will have both an AC and a DC
component. If only the DC component were measured, then the input enthalpy
would be underestimated. A detailed description of the current and voltage
measuring systems showing their fast response characters is needed, but is not
presented.
Since these three important aspects of the experiment have been omitted,
it is not possible to say whether or not excess enthalpy has been observed in
the last 600 seconds to dryness (stage three).
There are two important problems with stage two.
Firstly, a complicated non-linear regression analysis is employed to
allow a claim of excess enthalpy to be made. This method of Fleischmann
and Pons [2] has been carefully studied by Wilson et al. [4] who state that
"they significantly over-estimate the excess heat.......an additional
significant overestimate of excess energy occurs when the calibration is made
above 60 C". Now stage two is mainly above 50 C and rising to 100 C. Further
Wilson et al. write "Because of the paucity of experimental details in their
publications, it has been difficult to determine quantitatively, the effect of
calibration errors." A reply by Pons and Fleischmann [5] did not address the
main questions posed by Wilson et al.
Secondly, it may be noted in fig. 8 of ref 1, that the cell voltage rises
as the temperature rises and that as 100 C is approached, the voltage rises more
and more steeply. Experience by the GE group [6] was that in operating similar
open cells over many hours, they also noticed a rise in cell voltage with time.
They attributed this effect as being due to some of the escaping gases carrying
some Lithium with them. As the level of the electrolyte is maintained by
adding fresh D2O (but not any lithium salt), the concentration of lithium
in the electrolyte decreases with time and the voltage rises. This was proved by
atomic absorption analysis, that the cell resistance had risen (causing higher
voltage due to the constant current mode operation) due to loss of lithium
which was caused by sputtering of electrolyte droplets up the gas outlet tube.
This may be considered confirmation that even at moderate temperatures, the
outlet stream contains liquids as well as gases as discussed for stage three
when the temperature was much higher and the boiling much more vigorous.
It may be concluded that claims of excess enthalpy in stage two have not
been established.
The overall conclusion is that many important factors have been neglected
so that it has not been established that excess enthalpy was observed.
The experiment and some of the calculations have been described as "simple".
This is incorrect - the process involving chaotic motion, is complex and many
calibrations and corrections are needed. The calculations have been made to
appear simple by incorrectly ignoring important factors. It would have been
better to describe the experiments as "poor" rather than "simple". A true
"simple" experiment is one where corrections and calibrations can be reduced
to a minimum. This can be achieved in calorimetry by using a closed cell and by
enclosing the cell in a series (eg three) baths which are each kept at constant
temperature. The cell is kept at a higher temperature than the innermost bath
so that if any excess enthalpy is produced, the heating of this bath can be
reduced thus measuring simply the excess. Since this is a null measurement
system, there is little need for complicated corrections. It is to be regretted
that in the nine and a half years (the last four years well-funded) that
Fleischmann and Pons say they have been working on this [7], that they have
employed such a simplistic open-cell system.
It is a pleasure to acknowledge the help of many friends, in particular
D. Britz, F. Close, T. Droege, R. Garwin, and S.E. Jones.
REFERENCES
[1]. M.Fleischmann and S. Pons, Phys. Lett. A 176 (1993)1.
[2]. M. Fleischmann and S. Pons, M.W. Anderson, L.J. Li, and M. Hawkins,
J. Electroanal. Chem. 287(1990)293.
[3]. G. Kreysa, G. Marx, and W. Plieth, J. Electroanal. Chem. 268(1989)659.
[4]. R.H. Wilson, J.W. Bray, P.G. Kosky, H.B. Vakil, and F.G. Will,
J. Electroanal. Chem. 332(1992)1.
[5]. M. Fleischmann and S. Pons, J. Electroanal. Chem. 332(1992)33.
[6]. General Electric group of ref. 4. priv. comm.
[7]. Press release, University of Utah, 23 March 1989.
Arnie Frisch
>
> DM-93/3.
>5th DRAFT - Scientific Comments Welcomed. 6 May 1993.
>
> COMMENTS ON CLAIMS OF EXCESS ENTHALPY BY FLEISCHMANN AND PONS
> USING SIMPLE CELLS MADE TO BOIL
>
> Douglas R.O. Morrison.
>
This so thoroughly destroys their credibility that I have difficulty
believing their funding will continue. I also note, with gratification,
that Morrison describes the conditions as chaotic - mirroring my comment
about the complex dynamics of what is happening in that test tube.
Arnold Frisch
Tektronix Laboratories
Dick Jackson
total energy from start to finish of the "boiling cell" experiment, or
do they compare power in and out at various times? My casual reading of
Dr. Morrison's very interesting paper seems to indicate the latter. If the
first approach, then surely the energy/power from the "cigarette lighter
effect" is taken into acccount and the criticism is not justified.
If the latter, my mind boggles -- Dr. Morrison has if anything understated
his criticisms.
Dick Jackson