No-one is saying here that entrainment (of the different types possible) needs to happen. Only that if the apparent heat balance is wrong, entrainment is one possible reason for the discrepancy. LENR is another, as is mismearurement due to wrong chracterisation of water level. Before reaching for LENR all the mundane possibilities such as entrainment need to be considered and ruled out (that means careful sympathetic consideration, rather than blanket dismissal). Thus it is fair to give mundane mechanisms here the same careful and sympathetic attention that people on this site would most likely give to an LENR hypothesis.
More generally, the F&P experiment had very different condition at different times, so all these arguments need to restricted to specific conditions where they can more accurately be estimated, and not generalised over other conditions - as some the the argument above appears to be doing.
OK, you don't say that entrainment needs to happen, but my comment was intended to overcome the Rothwell's objections to the entrainment issue, which imply that it is the only alternative to LENR as an explanation of apparent energy imbalance in the boil-off experiments of F&P.
Since the first critiques raised by Morrison and others, who saw in the foam entrainment a possible explanation to close in a mundane way the energy balance, F&P opposed the fact that after the boil-off they recovered 95% of the initial alkali inventory.
This argument has been opposed by Rothwell to anyone who tried to explain the XH with liquid entrainment:
From http://www.infinite-energy.com…/pdfs/JapaneseProgram.pdf (Infinite Energy, July 1997)
… Fleischmann explained to Steve Jones in September 1993: “One could say some of the D2O is dispelled as droplets (actually, we recover ~95% of the alkali by dissolving the residues and titrating; some is undoubtedly lost by irreversible reactions with the glass walls of the Dewars.)”
… On the other hand, as far as is known, entrainment has never been observed to cause more than a minor error, no more than a few percent. We cannot imagine how it could carry off most of the water and cause 50% to 300% apparent excess, like that measured using boil-off calorimetry at IMRA and the French AEC. Rothwell asked Kennel how much apparent excess heat this artifact produced, but he did not respond. We suspect the NHE saw marginal artifactual heat, a few percent at most. They determined it was caused by entrainment and they decided to circulate the rumor than the same mechanism can explain Pons and Fleischmannʼs results too, as if foam could remove two-thirds of the water from the bottom of a tall test tube. Rothwell thinks the NHE researchers are casting about for a reason to discredit Pons and Fleischmann. They have not been able to replicate, so they want the world to believe there is nothing to replicate, it was all a mistake in the first place.
Therefore, in order to reconcile the entrainment hypothesis with the alkali recovery, someone (I don't know who was the first) began to propose the recondensation mechanism, to which Rothwell opposed the usual argument until today, for instance in the following recent comment on L-F:
From: Where is the LENR goal line, and how best do we get there? (September 18, 2018)
The recondensed liquid does not leave the retort. It falls back in. If it left the retort, the distillate would have a lot of contamination, so the retort would not work. In this case, even recondensed water would have some salts from the walls, if it left the cell. Therefore this mechanism cannot produce apparent excess heat.
Even if a tiny amount of recondensed water leaves the cell, it would not be enough to change the apparent heat balance to produce 100 W of spurious (artifact) heat. Given the input power to the cell, nearly all of water leaving the cell would have to be in liquid state for that to happen. It would be readily apparent to the naked eye. Contrary to what you say, steam at ~1 atm cannot push liquid water up an open tube, but even if we accept that it can -- for the sake of argument -- it cannot push up most of the liquid water in cell up. Nor is there any way that much water could recondense without nearly all of it falling back down.
Well, we should admit that, on this specific aspect, Rothwell was right: recondensation can't explain the alleged excess heat in a mundane way. More generally, he was right in saying that no other entrainment mechanism, like those listed in my previous comment (1), can explain more than a few percent of apparent excess heat. On this point, I was wrong too, as admitted in the previous comment.
What I wanted to say now is that the simplest and most effective mundane explanation of the apparent excess heat in the F&P boil-off experiment is their misrepresentation of the entire boil-off period or, as you have called it, the "mismeasurement due to wrong characterisation of water level". This alternative interpretation of the F&P results can easily explain both the 100% of the energy mismatch (minus the few percents of possible entrainment) and the 95% of salt recovery (whose deficit could be explained with the marginal entrainment which caused the progressive dilution of the electrolyte during the first period of heating up).
What I propose to anyone, who is aimed at the desire to arrive at a general accepted interpretation of the F&P results reported in their 1992 paper, is to focus on this simple explanation, bringing some more argument which could help solving the last doubts.
The clarification on the misrepresentation of the boiling phase would be immediate if we could access the original data logging and the entire video recording. It's probable that these data are still circulating in the LENR community. It would be necessary to bring them out.
A suitable opportunity to do it and to review in deeper detail the old F&P experiments, would be the next "2019 LANR/CF Colloquium at MIT" which is scheduled for the 30° anniversary of the F&P press conference. Isn't it? I'm not in the condition to launch such an initiative, but maybe some L-F members, who are primarily interested in knowing the truth and have some scientific authoritativeness, can do so. What do you think about?