On the Thermal Stability of the LENR Tube (Esko Lyytinen)

The following post was submitted by Esko Lyytinen

I think that the next kind of thinking and study is very essential to successful replication of the Rossi effect and further replications of the Parkhomov replication, with hoped-for good COP. I don’t think I have seen this discussed, but I’m not for sure — I am a long time follower of this site, but have not read everything.

(This kind of thinking is (for the most part) also quite new to me. I got to this thinking-chain when waking in the night and was kept awake for about 3 hours thinking this. This thinking of course continued when better awake.)

There are simplified assumptions in this, but even in a more complex situation, this kind of analysis is very important. We do not practically know some of the critical parameters, but some general level even conclusions can be reached. I have in this also some conclusions, but most of what follows may not be quite final. This is mainly to encourage further study and discussions.

Most of the existing discussions have been on the fuel composition, etc, but even if one has very good composition of the fuel, the discussed things may totally prevent a good COP with the setup and/or inevitably lead to the destruction of the tube/stick/bone.

The very recent results by Lenz team from Moscow (with DC energy input) may tell that to have the reaction is mainly dependent of the temperature with magnetic things of less or no importance. And even IF the magnetic things are of importance, the next type of analysis is still important.

I will now make simplified assumptions and try to avoid mathematical expressions with derivates etc. I try to explain some of the concepts by describing these, in order to give a god idea on these.
This does not deal with nuclear things, but only assumes that the reaction exists and is a function of the temperature (here dealt with the absolute temperature in Kelvin). The amount of heat is of course dependent of the amount of the fuel, (maybe can assume proportional to this). And there may be other things affecting things. Also the short and long term history are probably more or less affecting. But here we concentrate on the dependency by temperature.

Assume, that the dependency of energy by temperature in a given working point (temperature), can be described by a constant E. If the absolute temperature increases by 1% (or any small amount) and the power output also increases by 1% (the same proportional small amount), then E=1. If 1% temperature increase increases the power by 2% then E=2, etc. Here the power is the release of power form the reaction only.

Then we consider the thermal outflow from the reaction. IF all this were by the thermal radiation, then the outflow would be practically proportional to the fourth power of absolute temperature (assuming a not very warm ambient). We denote this coefficient of the reactor by R (not to mix to electric resistance ), which in the case would be 4. (In this we assume the outflow to be the same than energy generation at leas for a moment. Or we can in this consider the properties of the tube only independent of where the energy inside comes.)

On the other end, if the outflow would be completely by thermal conductivity to the ambient of 0 deg Kelvin (which of course is not reasonable). Then would be R=1. With some more reasonable ambient temperature, the R would be bigger than 1, much bigger if the reactor temperature were quite low, but would tend to get smaller towards 1 if the reactor temperature increases a lot above the ambient temperature.

IF there is no active regulation, then the condition for stability is: E R, then the increase of energy (from some temperature increase) would lead to even bigger further increase of temperature etc, leading to non-stabile run-away.

In the above we were thinking the R to be dependent only from the LENR energy. And the stability condition would then be even to complete ssm (self sustain mode). To have this, then also the amount of fuel should be just correct for the given working temperature.

Assume that there is some electric (or some other type) energy also in use in a non-ssm situation. IF we assume (for example) that the used energy is as big as the energy from the reaction, then a given increase of absolute temperature of say 1 % increases the total (reaction plus input) outflow of energy by 0.5*E*1%. We denote the (in this case) 0.5*E by Eef.

Now the COP=2 and more general thermal stability condition is Eef < R .

This situation now is of course more stable than in the assumed ssm condition. For each case the amount of fuel must also be suitable to this COP and working temperature. And in general it is easier to get the stability with smallish COP. If this condition is not fulfilled, it would appear that Eef is decreased by increasing the input energy, but this would of course increase the temperature and lead to an even more bad situation. The amount of fuel would need to be reduced to get it stable at all with any COP (near this temperature).

As to the suggested further study, the numeric dependency of the LENR energy by temperature would be most desirable. In principle (if having a working fuel etc) this could be measured with smallish amount of fuel and smallish COP, needing then of course good calibration and measurements.

I also do some further speculation on this by doing some assumptions of the value of E. The E is most probably ( a lot ) bigger than 1. IF this is somewhere between 3 and 4, then with these assumptions a thermally stable reactor in ssm would be possible. But for example some amount of the energy flows out by convection, for example making the R of the reactor smaller than 4, maybe around 3. (Some numbers could be retrieved from the Lugano test for example, I think, but did not try this.) Also the energy inside the tube first flows out by conduction trough the tube wall, this decreases the R of the tube and so also the.

IF The coefficient might indeed be this big, then all optimization in this would be very desirable to get a good COP. This includes also for example the wall thickness. As the coils tend to be around the tube and fuel, this also increases the wall thickness and decreases the R value. In this respect it would be desirable to have the coil inside the fuel. This would make the requirements of big temperature-durability of the coil even more important. (Might it be possible to have inside a gas-discharge tube to supply the electric input-energy.)

This kind of thinking makes is also quite clear, why it is so difficult to generate electricity with the Hot-Cat even with big enough temperature that can be reached. If one would have even a completely ssm-working reactor, to effectively couple this for example to a stirling-engine, would most probably result into a smallish COP or thermal instability of the reactor. All these things would need to reconsider very carefully. Also trying to use a flow calorimeter with a reactor that works well in the infrared thermal calibration, may not be quite simple for hopes of similarly good COP:

And considering for example attempts to further replicate the Parkhomov – replication, even if one has the very same fuel and (for example same amount) but has his own tube design, and tries to get it functioning at the same temperature than Parkhomov had in use, this would quite probably result to either smaller COP or thermal instability, this latest MAYBE even by necessity (independently of however carefully the temperature is increased). Only with some good luck would one get as good or better results in the COP.

Every known replication has needed several broken rector tubes. IF/WHEN getting to some more analysis of these stability issues is expected to be helpful in this.

With active input energy control the things may be somewhat easier. Then the control would need to be based on temperature measurements in (or very close) the fuel. But even then, if desired to get close to ssm, the stability considerations are very relevant.

And further, IF the above stability condition is true for the whole tube, any non-smoothness of the fuel (or warming coil) may locally get the situation as non-stable. So, it is of very big importance to have the fuel very evenly distributed.

In my opinion Rossi himself has made these kind of analysis quite thoroughly (with the hot-cat and also the (less hot) Ecat). And as to his recent new idea and version of his hot cat, I don’t know but I am expecting his new insight to have something to do with the stability issues.

Esko Lyytinen

  • Allan Kiik

    Rossi started talking about longer SSM-s and better overall performance in connection with control system of 1MW plant, and this can be understood as a function of *heat removal*!
    When you have only natural radiation & convection, your system is limited – you can not dissipate much more when the reaction starts and this must lead to failure, unless you have some *really fast* way to detect started reaction, much faster than temperature indication which is far too slow.
    And even then you can not have good COP without active and precisely controllable heat removal, for COP of 10 you must have the way to remove 10 times more heat than your heater supplies.

    • the COP is not the important factor, but it’s variation with heat (in fact just power vs temperature curve, power in is of no importance except in that it increase temperature by injecting additional heat).
      if COP was stable there would be no runaway.

      • Axil Axil

        The COP of the “mouse” is just over 1. The “mouse” will not loss control. The purpose of the “mouse” is to convert the heat into coherent heat. The “cat” will not loss control because it is controlled by the “mouse” which is stable.

    • Esko Lyytinen

      When starting to write this new comment there were
      zero comments in my original post and now when planning to submit, there are valuable
      comments by AlainCO and Allan Kiik, thank you.

      The next is written before reading these. And Allan
      Kiik discusses on the removal of energy, more or less along the lines of this
      thinking. I will need to read these more crefully.


      This comment may not appear very quickly, because I
      am not registered (sorry for this) even though quite regularly following this. Presently
      there are so many needed registrations that I have avoided to register if not very
      necessary. I may need to register, if/when commenting somewhat more frequently

      I have here some further comments to this topic.

      One may ask, if there is any sense to take out for
      example 2 kW and at the same time input 1 kW. Why not to take out only 1 kW and
      input nothing. But, YES we all know that there is sense in this, in order to
      try to control the reactor with this.

      But in my opinion the reactor can be constructed in
      a different way. I explain my thoughts on this. The main point is that the
      control is done by the removal (output) of energy, not by inputting it.
      This “removal” would the need
      (at least in the simplest solution) to be strongly controlled. The reactor could
      have the next type construction.

      There is an inner cylinder with the LENR fuel
      inside and this would have preferably thin walls. It would also be helpful to
      have its diameter bigger than needed to contain the fuel. Then the fuel needs
      to be distributed evenly on the inner side.

      Around this inner cylinder, there would be an
      “empty” space or space for the coolant to flow. The coolant could be
      (preferably compressed) gas. Covering
      this is the resistive coil for warming. And this is further covered with
      good thermal insulation to prevent non-wanted loss of heat energy.

      Optionally there could also be a coil for magnetic
      fields, if needed. This could be for example imbedded in the insulation
      material layer. This coil would be of low electric resistance and possibly a
      high Q circuit, if only one frequency were enough.

      The flow of coolant is maintained by machinery and
      controlled with the help of the inner reactor temperature. And this (the flow of the coolant) could
      lead into thermal exchanger (for actual use of the energy) or possibly to

      The mentioned, not so small diameter of the inner
      cylinder is helpful for good exchange of the temperature to both sides of this
      volume and also would allow strong cooling and output of energy as needed. The
      forced energy outflow would have quite a wide possible range of operation and
      this would make the amount of LENR fuel not so critical.

      The warming resistor would be needed ti warm to get
      a good start, but after this there ought to be only net output of energy and no
      need to input. And in this example both the input- and output energy concern
      the same volume making it more clear that there ought not to be any need to add
      energy after a good start and when the net is expected to be only outflow of
      the energy.

      There is no “label” or principal
      difference in between the input and output energies. Only the amount of total
      flow is expected to have real meaning in this. It should be capable of
      practically continuous ssm. I do not see any reasonable reason why this type of
      reactor could not function in practically continuous ssm. It would still need
      the energy for control and flow of the coolant and magnetic coil, if
      needed. But these needed energies are
      expected to be quite small.

      ( IF however the LENR energy (even in a fixed
      temperature) were very strongly variable in time, going some times near zero
      and the active again, could be the reason to use the warming coil and energy
      for this over the period of nearly null

      I do not mean that the ongoing tests would need to
      get changed to something like this. The properties and also the energy
      dependency on temperature etc can be further studied with radiation cooled type
      reactors. I hope good success to the MFMP group and others !!

      As to the LENR fuel, in my opinion there is not
      special property in the fuel to allow good COP and/or practically continuous
      ssm, only that there exists energy output in a reasonable temperature and that
      this property is sustained for an extended period of time without a fast
      decline of the effect. If effective at
      all there is no special characteristic COP for a fuel composition.

      If for example the energy generation (of the fuel)
      is one half of what a better mix of fuel can give, one only makes the mass of
      the fuel two times as big. These amounts are so small, something like 1 gram
      that this can easily be increased to several grams, as may be needed.

      There are of course still important secrets of the
      fuel and my purpose is not to negate the meaning of this, but the hoped for god
      success is as well dependent on the construction of the reactor and its thermal
      properties, (in addition to sustain high temperature and be airtight (hermetic)

  • great analysis.
    control is the key.

    in a way I understand the SSM mode.

    the fuel is a nonlinear dipole producing power more than proportionally to the temperature … the sweet point may be when this function is locally power variation is temperature variation at the power of something from 1 to 4… above it runaway, below no SSM mode.

    now the SSM can be explained if you consider that the E-cat is a chain of two components.
    one is a conduction line, that in electronic we describe as “transmission line”, made from elements of thermal resistance and thermal mass (resistor and capacitor)…

    then at the end of the transmission line you have the T^4 radiative element, which could be modeled in electronic as a highly non linear dipole, like a VCR (voltage controlled resistor) with I=X.V^4

    now SSM is simply accounting for the transmission line delay…
    inject heat to the point the LENr reaction start to runaway…
    heat wave propagate inside the E-cat thermal mass, and after some delay is dissipated as radiation. if you cycle at good period, it is stable.

    anyway this is not compatible with recent SSM improvement.
    I imagine that Rossi have build a meta-system where the crowd of E-cat make a longer transmission line emerge from their collective behavior… (in chain?)

    that is an idea to check with computations…

    • rereading I realise I mixed thermal and electronic vision.
      heat/heatflow and temperature are like charge/current and voltage…

      another point well explained in the article is that the non linearity of Nth power function translate into “1% input lead to N% output”

      the system is stable as soon as input=output on average.
      we can assume E-cat work around a chosen sweet point.

      I imagine the secret of SSM is that the sweet point change, or can be stabilized in due time, to keep that balance.

      as someone said here, the system have to react quickly enough to the increase of temperature. because of the delay induced by thermal mass and resistance, it maybe impossible.
      just injecting a pulse of heat and seeing the response few minutes later may allow better feedback.

      why SSM is better than stable mode, better COP without runaway, is strange for me… maybe it is because the reaction COP grows very fast with temperature and time, and thus it is better to twist the tail of the dragon and run fast, than to caress him kindly.

      maybe also the reaction is not so “stateless” and there is some “pumping” making SSM more stable at higher COP than stable mode.

      there is a need for computation to test those ideas. or experiments.

    • Axil Axil

      I described this subject before in this thread as follows:


      Polariton Coherent Light and Rossi’s Cat and Mouse
      Posted on June 18, 2015

      SSM is caused when the “mouse” drives the “Cat”. But the mouse drives the cat in a special way. The heat from the mouse is not the same as the heat from a wire heater. The heat from the mouse is “COHERENT”. Why is the light from a laser different from that produced by a flashlight? The light from the laser is “COHERENT”.


      The Mouse converts the heat produced from the wire heater into a coherent sourse of heat just in the same way the a laser converts a light from a flash driver of incoherent light into a coherent beam of light. The crystals inside the laser reformates the light so that it comes out as coherent.

      Why do you think that Leif Holmild gets 10^13 fusions of deuterium rydberg matter into helium using a laser flash. It is because the laser is producing coherent light.

      The mouse is synchronizing with the cat


      • bachcole

        I am very reluctant to doubt Axil^2, but how do you know that the heat from the Mouse is coherent?

        • Axil Axil

          We do not know that the mouse drives the cat using coherent heat, but we might suspect that it does. There must be some connection between the mouse and the cat whereby the mouse drives the cat.

          It must be some special form of EMF because the mouse is not powerful enough to drive the cat to a COP of 140 having only a COP just over one using pure strength.

          Once a working Hot cat is developed in an open source format, and the inventor is willing to do cat and mouse experimentation, and the inventor does those experiments, then we cannot know the way that the mouse drives the cat, we can only suspect it.

          • psi2u2

            I think you meant to write, “Until a working hot cat….”

      • Stephen

        Hi Axil, I wonder if something like these Luttinger liquid plasmons in nanotubes can be used to direct and position them to particular locations and active sites.


        But I suppose this kind of nano engineering is far off. Could be interesting for nano scale LENR some day

  • Esko Lyytinen

    I see a defect in my original text as displayed, in:

    IF there is no active regulation, then the condition for stability is: E R, then the increase of energy (from some temperature increase) would lead to even bigger further increase of temperature etc, leading to non-stabile run-away.”

    In the original document this reads:

    IF there is no active regulation, then the condition for stability is;
    E R , then the increase of energy (from some temperature increase) would lead to even bigger further increase of temperature etc, leading to non-stabile run-away.)

  • Esko Lyytinen

    I see a defect in my original text as displayed, in:

    IF there is no active regulation, then the condition for stability is: E R, then the increase of energy (from some temperature increase) would lead to even bigger further increase of temperature etc, leading to non-stabile run-away.”

    In my original Word document this reads correctly:

    IF there is no active regulation, then the condition for stability is;
    E R , then the increase of energy (from some temperature increase) would lead to even bigger further increase of temperature etc, leading to non-stabile run-away.)

  • James Andrew Rovnak

    Since LENR is a very high density energy source, should the fuel element be treated as a homogeneous mixture connected to temperature or just maybe local sites that are promoted in growth by EM stimulation ( preferably by an alternating time varying B field from the heating coil) of local surface plasmon politons (SPP) for Ultra Low Momentun neutron generation to drive the process. Many of the experiments have noted very hot spots on the fuel elements exterior & failure very locally with thermal overload indicated post test. The last MFMP Padua Reheat test showed such a hot spot even sifting from one side of the element to the other at various times during the four day test. Note that the current source in the tests came from a TRIAC but was unidirectional so the B field was not alternating in direction as with Rossi’s & Parkhomov’s successful TRIAC based tests. Many claim DC current also produce (ssm) LENR but they were subjected to on/off large currents & are not consistently started nor controlled to present a viable commercial power source. I think there is a time constant associated with local (ssm) generation & interrupting with the appropriate current power pulse can either raise or lower the process’s extent in the fuel element. How else does Rossi get extended (ssm) LENR with no external power input? Again just maybe? Suggest we explore in the 60 – 10 hertz range the effect on LENR possible resonance reaction or even a broader spectrum by switching polarity to the coil at various rates possible by another series set of semiconductor switches to coils. Rossi claims control from 700 to 1500 C – wonder if that is (ssm) LENR regions of successful operation with appropriate care in getting & staying there . It sure does require his personnel attention 24/7 or until a better fuzzy digital controller can replicate that attention.