Rossi Lugano/early demo's revisited. (technical)

    Quote from Wyttenbach

    interesting that LENR deniers can quote such a fact without asking the question why a pure Ohmic heater of < 500 grams needs 17 minutes for reaching a steady state...

    The thermal gradient to the inside is much, much less than the thermal gradient to the outside. So most of the heat goes to the outside, leaving little to heat the core. At steady state the core temperature is actually similar to the coil temperature (how could it be any higher by conduction?). The core is 10 mm from the heater coil, while the outside is 2.5 mm away and has a very large favourable thermal gradient, with an “infinite” ambient (low temperature) reservoir to fill, aided by convection and radiation which is much more effective than conduction heat transfer.


    Feel free to calculate what percentage of heat flows outward from the coil compared to flowing inward, as a function of time starting from a substantial coil temperature increase.


    Placing the cylinder into a highly insulated cavity will greatly increase the rate at which the steady state condition is reached, by strongly limiting heat transfer outward, so more heat is available to heat the core.


    One could similarly ask why it takes the outside only about 11 minutes to cool from 750 C to 200 C, but over an hour to cool from 200 C to 20 C.

    Quote from Paradigmnoia

    Sorry, but did I miss your original point?


    An ohmic heater takes a few seconds - after it reached target T - to get to stable point because heat flow is linear. Especially in cases/ with materials you look at, that have very good heat conduction.


    Conclusion: In the Lugano case we deal with a non ohmic, nuclear heating source.

    Quote from Wyttenbach

    An ohmic heater takes a few seconds - after it reached target T - to get to stable point because heat flow is linear. Especially in cases/ with materials you look at, that have very good heat conduction.


    Conclusion: In the Lugano case we deal with a non ohmic, nuclear heating source.


    I fail to see how you come to that conclusion.


    The ohmic heater is Kanthal A1, at least until the ceramic gets really hot. The ceramic is many times the mass of the Kanthal wire that it is bonded to.


    Have you forgotten:

    .

    Quote from RobertBryant

    What sort of control?

    No fuel.


    There is no fuel. There is no place to put fuel.

    There are two Type K thermocouples (one cast into the center, one cast into the exterior surface), a Kanthal A1 coil wire with doubled over connection leads, all sealed in Durapot 810. The coil is 2.5 mm below the exterior surface. The diameter is 2.5 cm, and it is 6.6 cm long.


    It looks like this:

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    .

    Quote from RobertBryant

    I thought you might compare fuel with no fuel


    Otherwise there are too many variables which you can't simulate/ control


    Seems pointless to do such experiments otherwise


    This no-fuel device made a "COP" of 7.2 using the Lugano methodology. COP of nearly one every time done the right way.

    Understanding a null device is very useful for understanding what the variables are and what actually is anomalous.


    Here it is at an actual 1107 C (2140 L) surface temperature in the middle 3.5 cm.

    .

    .

    Note in the upper LH side is the ambient temperature thermocouple embedded into an alumina BBQ tile. One of the very first IR test pieces I made in investigating the Lugano report after it came out. I would heat it on the fireplace, frying pans, oil stoves, propane torch... I have used it for the ambient temperature sensor ever since I went electric.

    Paradigmnoia


    The reason it took a long time in the "waiting for it" is that I already knew what voltage input would steady-state a 1410 (Lugano/IR 0.39 E) temperature, and so I set it there.


    Basically by setting directly the voltage you set the new power level.

    This is what the MFMP in their retest also did, a stepwise change in power.

    And that gave a settling time of about 400 seconds, not the long time of 17 minutes you mentioned.

    So I was still wondering why it takes such a long time in your tests.


    It is much quicker to feed in as much power as is sustainable, and then reduce to the known steady state voltage once the temperature gets to the desired point (you can see that I did it a little bit early in the Fast Ramp).


    Agreed that feeding maximum power, then wait till the required temperature is arrived and then drossel back will be faster.


    So, one can see that the power in Lugano was not turned up sharply, but rather just a little bit and then some waiting to see what happened.


    That might not be true. The report states :


    ... showing how long it took the E-Cat to stabilize after input current was increased.

    As one can see, this amounts to about 400 seconds


    So the 400 seconds period is after the current was increased.


    (I do have some doubts about a third adjustment in the Plot 5 trace. That could just be some random bump.)


    Some initial tests I am now doing are also showing a bump at about the third position.

    This bump seems to be physical since it occured after lowering the thermal conductivity of the Durapot.

    I have however no explanation why this should be the case.

    Maybe dumping intermediate physical values from the simulation will tell more. (Again something for the future because I can spend only very limited time on this currently)

    Note that the long drop time period just before the "waiting for it" it is the same as the waiting for it climb time period, because I set the lower voltage to the already known 1300 0.39 E steady state level and waited for it to cool to steady state.


    Which indeed should be the case.


    LDM ,

    What temperature step did the MFMP do that you are referring to? Which video?

    Note that the start temperature makes a big difference in the settling period.

    Note also that the MFMP Dogbone feeds about 30% more power to the ribs area than the Lugano device did at the same input level, due to the lack of heated coil extension wires in the MFMP device.

    Using the MFMP Thermal Validation data file, I get the following temperature-times to steady state (the time stamps are a bit odd in the second example, file seems to have repeated 12:00, so I just changed the second "12" to a "01", since the rest seemed OK).

    I would have to try and match an MFMP temperature step for a decent comparison.


    ** Check out how hot the MFMP Dogbone is inside when the outside is at 677-678 C , compared to the inside of my Cylinder when it is 676 C outside! What's up with that? **


    Time-------------------Outside T-----------Time-------------Inside T

    12:00:11--------------554.1-----------------12:00:05--------720.8

    12:27:05--------------677.39---------------12:39:45--------942.3

    ____________________________________________________________

    00:26:54---------------------------------------00:39:40--------------------Elapsed Time

    .

    .

    Time-------------------Outside T-----------Time-------------Inside T

    12:52:47--------------678.446-------------12:52:47--------942.211

    01:01:48--------------718.059-------------01:04:58--------1026.98

    ___________________________________________________________

    00:09:01--------------------------------------00:12:11--------------------Elapsed Time

    .....................................................................................................................................................................


    My first "Bump" image:

    Time-------------------Outside T-----------Time-------------Inside T

    22:05:39--------------596.6------------------22:05:39--------659.4

    22:19:23--------------676.6------------------22:26:15--------773.4

    ____________________________________________________________

    00:13:44----------------------------------------00:20:36-------------------Elapsed Time
    .

    .

    Waiting For It:

    Time-------------------Outside T-----------Time-------------Inside T

    23:12:10--------------701.2-----------------23:12:10---------777.9

    23:20:52--------------753.8-----------------23:21:14---------842.3

    ____________________________________________________________

    00:08:42---------------------------------------00:09:04--------------------Elapsed Time

    Quote from Paradigmnoia

    LDM ,

    What temperature step did the MFMP do that you are referring to? Which video?

    Note that the start temperature makes a big difference in the settling period.

    Note also that the MFMP Dogbone feeds about 30% more power to the ribs area than the Lugano device did at the same input level, due to the lack of heated coil extension wires in the MFMP device.


    It was not from the video but from the logged temperatures of the internal TC

    See the following file of the MFMP Dogbone thermal retest.


    DB_test1_500-900W_TC.csv


    But a lot depends on when you consider it stable


    That's why I prefer to use the exponentional time constant instead of the stable time.

    These are the last stable T sample before a continuous climb at the time start, and the highest flatline temperature before falling slightly sample for the end of the time period. So these are minimum time periods in the table above. Over an additional hour of “steady state”, the temperature could probably still climb another 4 or 5 degrees.

    Quote from Alan Smith

    LDM Dead Link :(

    Sorry Alan,


    I don't have the link anymore but am almost sure that Para has the file himself.

    Could have added the file as an attachment, but am not sure if the MFMP would allow that.

    (Intelectual property laws are becomming ever more stringent)

    But I think that Para possibly knows the location, so maybe he can provide the link.

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