I’m saying if you like to ride unicycles on top of unicycles then have at it.
MIZUNO REPLICATION AND MATERIALS ONLY
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I’m saying if you like to ride unicycles on top of unicycles then have at it.
I am asking about your own empirical observations. Do you find that establishing temperature control is markedly more difficult in an oven with an active reactor compared to a nonactive reactor?
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Only when the heat captured by the air flow is less than input energy. When there is a lot of excess heat, the heat captured in the flow exceeds input energy, and you can ignore errors in other heat flow paths.
Yes. Good point!
One of the eccentricities of the Mizuno results with air-flow calorimetry was that the heat captured by the flowing air never rose above the input power. Even weirder, that it was often almost equal to input power. I recall that this worried you too.
I wonder what the situation with Daniel_G's oven setup is.
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This is part II of my exploration of the consequences of harvesting heat in a simple model of a thermal mass with Newtonian cooling, a source of externally controllable heat delivery (the input), and an internal source of heat generation that is temperature dependent. The temperature dependence-of internal heating is described using an Arrhenius function with the activation energy measured empirically by Mizuno.
I am numbering my results and will continue the numbering from where I left off in my previous post except that I will first set the stage by reposting the first figure from last time
Result 1 (recap): Here is the time course of heating in response to turning on a moderate level of input power. "Moderate, here, is defined as an input that ends up activating only a small portion (~1%) of the maximal internal heat available.
Result 4 (new result, so continuing numbering from before): Increasing the input power by 25% results in a >25% larger temperature response (note the difference in temperature scale). Nonetheless, the overall behaviour is about the same as before and the steady-state excess heat activation is still only about 2% of maximum.
Result 5: Increasing the input power by only 10% more leads to a qualitatively different type of behaviour. Once the temperature goes past a threshold the system enters a regime of temperature instability. In this region, the internal heating establishes a positive feedback as the increased temperature provokes more activation which, in turn, provokes higher temperatures, etc. Below the threshold, increases in activation were more than balanced by increases in cooling, now they are not. This creates an inflection in the temperature time course. By the end of the segment shown below, the steady-state activation is more than 50% of maximum. The new, high-temperature steady state (note, once again, the revised temperature scale) is a reflection of the sigmoidal nature of the Arrhenius function. If activation was purely exponential, and not sigmoidal, there would be no high-temperature equilibrium at all and once temperature threshold sis passed the system would increase in temperature without limit.
Result 6: Once you have crossed the threshold and entered a high-temperature steady state, you can turn off the input power and the internal heating remains activated. It is like lighting a fire in your fireplace. You use a match to light it but once the fire catches you can blow out the match. In the figure below the input power is turned off at time t = 30
Remarks: All of this is implicit as soon as you add a source of temperature-activated heating to a thermal mass. The results are generic in the sense that, for such a system there should always be a threshold beyond which temperatures become unstable. The only question for particular situations is where the threshold is and how it relates to the actual physical properties of the system such as melting points of the components.
So much for Part II. Next time I will show what happens when you add heat harvesting to the mix.
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One of the eccentricities of the Mizuno results with air-flow calorimetry was that the heat captured by the flowing air never rose above the input power
that's only weird if you didn't understand calorimetry and calibration. I would say coincidental but not weird.
When the order of Axh and heat removal from the air flow calorimeter are close to each other this would be the expected result. Nothing weird about it at all. Keeping more heat in the oven will naturally increase COP relative to the air flow calorimeter. Our externally produced data will hopefully support this hypothesis robustly. Reducing air flow will also increase COP. Runway would be simply defined by the point where Axh exceeds the total heat outflow from the calorimeter. Obviously that point would be easier to reach in a small well insulated box than in one with a continuous flow of RT air coming into to it.
I am waiting for the updated higher power calibration numbers from the validator but at minimum will be 400W Axh, perhaps as high as 650W which would push the COP to 2. I guess you wouldn't be happy with that since output = input + input. That would be weird too, right?
New larger reactors will have much higher outputs and new oven calorimeters should increase COP to much higher levels. Let's see. I will need to work more and post here less to get this done!
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One of the eccentricities of the Mizuno results with air-flow calorimetry was that the heat captured by the flowing air never rose above the input power.
Incorrect. It did rise well above the input power on some occasions. See p. 5 and Fig. 5:
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Incorrect. It did rise well above the input power on some occasions. See p. 5 and Fig. 5:
There are two times that I recall. Years apart.
A thin layer of insulation and a dedicated air inlet could have made it happen every time. -
Should I have put the happy face emoji at the end?
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This is part III of my exploring the consequences of a temperature-sensitive source of internal heat generation in a thermal mass. My model is very simple. It really consists of nothing but standard thermodynamics and the sort of properties that Daniel_G and others believe characterize LENR heating.
I have already shown that if you heat the thermal mass in the model above a temperature threshold, the positive feedback of the temperature-sensitive internal heating causes the system to become unstable. The temperature rises either forever (if the temperature-dependence of activation is purely exponential) or up to a high stable state (if activation is sigmoidal with temperature). Once beyond the threshold and into the high-temperature state, you can turn off the external input and the system will stay at high temperatures. At this point the COP is infinity.
Now I ask will look at harvesting heat from the system while it is in the infinite COP state...
Result 7: Below is the temperature response to initial external heating to shove the system to the high-temperature state followed by the external heating being turned off at time t = 30. The behaviour is very much like Result 6 in my pervious post. The difference here is that not only is external heating turned off, but heat is additionally being harvested. The result is that temperature declines somewhat but still there is no external heating required to maintain the system in a high-temperature state. Energy that can be used to perform work is being siphoned off here (at just under twice the rate of the now extinguished external input). Mathematically this is a new stable state and could last indefinitely. Physically, the stable state would only last as long as raw materials for the reaction (deuterium?) last.
Result 8: Too much energy harvest can collapse the system out of the high-temperature state. Here (below) the rate of energy harvest has been increased by 25% beyond its setting in the figure above. A new threshold is now relevant. Once the temperature of the system goes below that threshold the positive feedback of the internal heating no longer beats out cooling and the systems collapses back to a stable state near room temperature. The temperature threshold for getting into the high-temperature state and that for collapsing out of it are not the same. The collapse threshold is at a higher temperature than the ignition threshold. Together these set an range of temperatures within which the system must operate in order to continuously withdraw energy at COP = infinity.
Result 9: It is hard to hold the system at temperatures where it doesn't want to be. The figure below shows an attempt to hold the model system below the 2000C operating temperature at which it would like to sit. In an attempt to hold the system near 1000C I I have turned off external input heating and turned on energy harvest early, at time t = 15. The system lingers near the desired 1000C for a while but then escapes up to near 2000C even though the energy harvest is unchanged. If I turn up the energy harvest rate marginally (by less than 0.5%) in an effort to keep the system near 1000C indefinitely, the systems collapses back to room temperature (not shown). I think, though, that with a sufficiently aggressive feedback control system that supplies a little bit of extra heating or cooling just when needed you might be able to regain stability. It is a bit like a fission reactor in that sense.
Remarks:
1) The red traces in the figures above always show the temperature response of a non-active system to the same input ... just for reference. Also, all figures were generated from systems in which internal heat activation is sigmoidally dependent on temperature (Arrhenius function). If the activation is purely exponential then there is no stable high-temperature state. Any energy harvest would have to be accomplished while using some sort of aggressive control system of the sort mentioned above to stop temperatures from either going up forever or collapsing down to room temperature.
2) All the temperature thresholds that shape the behaviours of the system can be calculated in closed form. Given sufficient knowledge of the parameters of the system you can predict how much energy you can get out of it and at what temperatures.
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Not sure where to post... Clean Planet thread, Mizuno thread, Navy or Next steps...
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These systems are in general ones which produce intermittent bursts of heat, rather than a steady output. it makes the calorimetry much more complex of course, whereas steady state behaviour lends itself to modelling more readily.
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In 2018 I found that if you take the model I have been talking about here and add one more variable (in addition to temperature) you get bursting. At the time, I called that variable "inactivation". It would be something that opposes the generation of internal heat. Inactivation could be thought of, for instance, as local poisoning of the reaction by the end products or exhaustion of reactants. When inactivation builds up the temperature collapses back to ambient but then then slowly dissipates to allow a new burst to form.
Here is a diagram I made at the time. In the top 2 panels black shows the temperature response of a control reactor and red is the temperature of an lenr-active reactor. In the bottom the black trace is the temperature of an lenr-active reactor. Grey is inactivation. Input heating is continuous, not pulsatile. The bursting arises due to the internal dynamics of temperature and inactivation.
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I prefer doing real experiments and then designing a model later that fits the data. Doing it your way, is a bit like the tail wagging the dog.
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Mizuno has reactors that ran for more than 20 months so not sure how relevant your model is to actual working reactors
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Mizuno has reactors that ran for more than 20 months so not sure how relevant your model is to actual working reactors
Bursty behaviour is also seen in long-lived systems. They are intermittent in nature - which Mizuno's systems may also be, since your methods would not show this easily due to system thermal mass and scale. Also the 'graininess' factor is important. 2 minutes on, 2 minutes off is easy to see in many systems, but 2 secs on 2 secs off almost impossible.
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Alan I agree but we believe scaled up systems won’t have this issue since a much larger number of active sites will average out.
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I prefer doing real experiments and then designing a model later that fits the data. Doing it your way, is a bit like the tail wagging the dog.
Well Mizuno has been doing real experiments for years. You have been doing experiments. I used these results in my model. And the overall nature of heat flow is well known, so I used that too. I haven't posited a particular mechanism for heat generation. Everything I have said would work for chemical heating or joule heating too if they delivered heat in a temperature-sensitive manner as you are claiming happens in your system. Really, all I am doing is thinking carefully about what happens when your claims for your LENR heating are taken seriously.
And you are model making too. In your head. Based on your experience and understanding you create chains of reasoning to guide your future actions. For instance the following ...
"No input power is required if your control system removes only the excess heat. Envision a system that reaches operating temperature of 600C and continues heating to 650C. A heat transfer medium leaving the reactor at 650C and returning at 600C would require input power? (hint: the answer is no) Just like we don't leave the starter motor running on a Diesel engine..."
Well I certainly understand where you are coming from, but as a general statement this turns out not to be true. In the model I created, I found that harvesting excess heat is not sustainable unless the system is already in a state that doesn't need any input at all to sustain the working temperature. And you haven't seen that yet. So I don't see that your reasoning works.
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Perhaps my reasoning is wrong and yours is right. The data will tell us. I’m willing to be wrong. I believe I know what’s wrong with your model but no point to debate here until I get the data. Your models are well thought out indeed and that’s commendable.
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Bursty behaviour is also seen in long-lived systems. They are intermittent in nature - which Mizuno's systems may also be, since your methods would not show this easily due to system thermal mass and scale. Also the 'graininess' factor is important. 2 minutes on, 2 minutes off is easy to see in many systems, but 2 secs on 2 secs off almost impossible.
I of course agree but I would just comment that if we can’t detect the graininess in practical devices then at least for commercialization purposes it’s not so relevant
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Perhaps my reasoning is wrong and yours is right. The data will tell us. I’m willing to be wrong. I believe I know what’s wrong with your model but no point to debate here until I get the data. Your models are well thought out indeed and that’s commendable.
Well thank you.
I am willing to be wrong too. In fact that is almost exactly the purpose of super simple models such as the one I have made. In model making you have to make your assumptions super clear. Thus, when the model results begin to depart from observations you have a good shot at understanding what makes the model wrong or (more likely) incomplete. And that is a step towards knowledge.
I remark, however, that so far your data agree with my model.
