Calorimetry in cold fusion experiments

Calorimetry is an essential part of cold fusion experiments.

Critique

hkedi and Jones

In some electrolysis cells running at low voltage, internal recombination of hydrogen and oxygen can create the appearance of excess heat. This is called the "Faraday-efficiency effect".

In 1991-1993, a group of investigatorsharvnb|Shkedi et al.|1995|Ref=Shkedi1995|pp=1720-1731.] [harvnb|Shkedi|1996|Ref=Shkedi1996|p=133.] led by Zvi Shkedi built well-insulated light-water electrolysis cells and calorimeters which included the capability to measure the actual Faraday efficiency in real time. The average Faraday efficiency measured in these experiments was 78%. With this taken into account, the calculated excess heat was 0.13% +/- 0.48% of input power. If instead a Faraday efficiency of 100% was assumed, the apparent excess heat was 21%. The investigators concluded "All reports claiming the observation of excess heat should be accompanied by simultaneous measurements of the actual Faraday efficiency."harvnb|Shkedi et al.|1995|Ref=Shkedi1995.]

Jones et al. confirmed the Shkedi et al. findings and concluded: "Faradaic efficiencies less than 100% during electrolysis of water can account for reports of excess heat in 'cold fusion' cells."harvnb|Jones et al.|1995|Ref=Jones1995|p=1.]

Fritz Will, former president of the Electrochemical Society, noted in his review of Jones' paper that " [the] fraction of O₂ recombining with H₂ decreases significantly with increasing current density. [...] On the basis of their results at low current densities, a group of researchers recently concluded that H₂ + O₂ recombination is the source for the "excess heat' reported by other groups and attributed by some to 'cold fusion'. However, reported excess heat values, ranging from a low of 23% at 14 mA/cm² to a high of 3700% at 6 mA/cm², are much larger than can be explained by recombination. Whatever the explanation for the large amounts of excess heat reported by various groups, H₂ + O₂ recombination must be rejected as a tenable explanation." [harvnb|Will|1997|p=177.]

Edmund Storms labeled Jones' conclusions "a good example of biased reasoning", observing that " [Jones et. al.] measured the recombination fraction at very low currents, where [uncertainty] is high, and used these values to dismiss all measurements using open cells, without acknowledging that most successful studies used much higher currents or closed cells where this correction is unnecessary."harvnb|Storms|2007|p=195.]

Fleischmann measured Faraday efficiency in his cold fusion experiments and found it to be better than 99%.harvnb|Fleischmann et al.|1990|Ref=Fleischmann1990|p=301.]

hanahan

In 2002, Shanahan speculated the apparent excess heat signals were arising from a systematic error he called the calibration constant shift (CCS). [harvnb|Shanahan|2002.]

Shanahan reanalyzed calorimetric data provided by E. Storms under the assumption that no excess power was in fact present, and found that a minor (1-3%) change in the calorimeter calibration constants was all that was required to explain the apparent excess power. [harvnb|Shanahan|2002.] Shanahan also proposed that the cause of the shift was a redistribution of heat in the apparatus, which is similar to one of the earlier complaints against Fleischmann-Pons type of calorimetry (single point temperature measurement being suceptible to hot spots). Shanahan further speculated that such a redistribution might arise from unexpected hydrogen-oxygen recombination at the electrode.

In July 2003, Szpak, in a paper co-authored with Fleischmann, said that such recombination reaction is not supported by experimental results. [harvnb|Szpak|2004|Ref=Szpak2004.] Shanahan replied that the recombination Szpak and Fleishmann were discussing was not what Shanahan was discussing, and was therefore irrelevant. [harvnb|Shanahan|2005.] Three years later, Storms said that even when a large change in where a large amount of heat is generated within the cell is made on purpose in a flow calorimeter, little or no effect on the calibration constant is observed. [harvnb|Storms|2006.] Shanahan responded to Storms in a back-to-back publication that Storms' own data displayed just such effects and that such effects were capable of explaining Storms' excess heat signals. [harvnb|Shanahan|2006.] His response included a breakdown of the 10 experimental runs into 4 sequential sets based on what seemed to be a clear time-dependent shift or reset in the calibration constants. This time dependence suggests a chemical aging effect that was reversed by in-cell processing, further emphasizing the non-nuclear nature proposed by Shanahan. He concluded that the chemical explanation he presented deserves an honest experimental test.

In his book, Storms said that the 1.2 % variation of the calibration constants he measured proves that the calibration errors proposed by Shanahan are absent.harvnb|Storms|2007|p=41.] He also said that Seebeck and flow calorimeters are immune to these potential errors, although the isoperibolic method can be affected.harvnb|Storms|2007|p=172.] However Storms' book did not analyze Shanahan's final latest publication, which refuted these same points. [harvnb|Shanahan|2006.]

His final conclusion is that the conventional explanation for apparent excess heat must be tested along with the unconventional, 'cold fusion' explanation.

References

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