Artifacts in "hot-cat" replication experiments

My view about LENR experiments is more or less identical to Abd (and therefore not popular here). Focussing on getting high COP is not counterproductive. Instead, focusing on understanding and reducing experimental artifacts will give better results whether LENR in these systems is real or no.

I'm writing this thread because I've just thought of an artifact I had never before considered that would affect some, though not all, of these systems in unpredictable ways.

Where the difference between control and active runs is that powder (or different powder) is put inside the reactor, and the reactor is Al2O2, we have an issue because the effective emissivity of the fuel can alter the total reactor emissivity. Further, this effective emmisivity may change largely with tempoerature, in ways both reversible and non-reversible. The range of possible effects is wide open.

It is impossible to control for this effect because any chemical difference in fuel composition could alter things.

It can be removed completely as a possible artifact by encasing the al2o3 reactor body in a known light absorbent covering.

You get this weird artifact for systems that use temperature as a proxy for heat emitted. This is inherently unsafe, because anything that alters thermal resistance to ambient will change temperature but not heat. So although this particular artifact is specific to the translucency of alumina and can be easily prevented, in general it is not easy to be sure.

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So can you quantify just how big this effect may be 'in extremis' or are you just 'hand-waving'?

It would not be me hand-waving with no quantification, it would be anyone relying on those experiments?

I suspect the effect practically to me much much smaller than the in extremis bound. It is just not easy to bound it tightly.

For worst case we for example assume:
Al2O3 is transparent for say 80% of the integrated output power - that will be true at high enough temperature.
emissivity of core changes from 0 to 1 or vice versa (not very plausible, but can't be ruled out, and a 0.5 chnage is quite plausible)

We get a power/COP error for same temp of 80*(r1/r2)% where r1 = inner dia, r2 = outer dia.

e.g. if r1 = 0.5*r2 we have a 40% max error from this source.

Asking for precision in error bounbds where there are so many variables is not possible. Which is why the way through is better calorimetry, or better controls. In this case controls cannot solve the problem but an absorbent sheath can - or mass flow calorimetry of course...

The problem is that even though I suspect the real error to be much smaller than this you cannot prove it. To do so you need to el;iminate this error, but more generally you need to use some form of calorimetry less susceptibe to such errors...

@Tom

I have no real info about me356 so cannot comment on what are his results.

I agree this does not affect Zhang results. Zhang has a SS reactor but relies on the thermal resistance staying constant when he inserts it, removes it, inserts it again into an insulating envelope. He also relies on the temperature of the end staying constant when fuel could alter thermal conductivity along reactor. I'm also not quite sure how the temperature is sensed(sorry I have not looked at Bob's translation in detail - so don't take these comments as much good. But equally you can see that the setup can easily supply 20% or so variability.

Actually an SS reactor can easily vary in emissivity if the SS outside changes surface which it might after heating, so that is something to check. Zhang's device I think uses thermal resistance determined by insulation and therefore does not depend on variation in radiated energy.

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But this is not a problem which affects anything other than IR thermography, surely? Close-contact thermocouples will not show such errors.

The emissivity change still affects the output power for a given (TC determined) temperature. The issue is that because alumina is partially transparent this output power depends on a variable emissivity sensitive to the inner core physical and chemical state.

It needs restating: temperature is a bad proxy for power in these "radiating reactor" setups.

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I personally think that Parkhomov's earliest experiments used a good setup. To improve upon it, I would add more insulation to the calorimeter, extend the gap from the water being heated to the atmosphere via a long neck to make sure water vapor would be less likely to escape, and automate the addition of water.

I agree. That setup is never going to give very high accuracy, but if well done as you say (which can be pretty easily checked when replicated) it can give high confidence. And it is much simpler than any other high confidence setup. If Parkhomov had been able to replicate his original result then either he is dishonest or he has something very interesting. I never jump to think people dishonest.

As a variant, a central heating tank, well stirred, and well insulated, could store enough heat for a long run and not require automatic top-up, with pumped water heat exchange. That would also be bombproof (even more so in fact - the main issue is checking that it is properly stirred and counting the stirring and pumping power into the power budget. A good design could use convection currents. And multiple sensors could check stirring.