MIZUNO REPLICATION AND MATERIALS ONLY

Quote from Daniel_G

as promised this is the second draft design drawings of our new calorimeter that is aiming to reach infinite COP.

The inner shell is ceramic board insulation, surrounded by a vacuum insulated panel made from titanium and an outer layer of ceramic wool insulation.

The top hinged cover will have two ceramic bearing titanium tubes that will attach to a shaft to spin the circulation fans to make sure that the internal environment is highly turbulent with no hot or cold spots.

The principle of operation will be as I presented in our iccf24 talk. There will be multiple calibrated sensors place inside the hot portion to measure the temperature.

Calibration will record equilibrium temperatures at various power inputs. These calibrations should all give the same temperatures at the same heater power regardless whether it’s empty or a dummy reactor is inside.

Active runs will include our heat amplifier reactor and xsh will be recorded as the power output to reach the final equilibrium temperature vs. control calibration.

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Forgive me, but I'm still not clear who 'our' is. Are you still collaborating with Mizuno? He does not seem to have confirmed your prior comment that the two of you are still working together.

Not trying to be difficult, but I'm genuinely confused. You seem to be working with Mizuno, but not Mizuno Tech..?

It’s quite simple actually. It’s simple a titanium double walled box filled with ceramic insulation to prevent the walls from collapsing and then removing the air with a vacuum pump to further reduce heat flow.

Quote from orsova

Forgive me, but I'm still not clear who 'our' is. Are you still collaborating with Mizuno? He does not seem to have confirmed your prior comment that the two of you are still working together.

Not trying to be difficult, but I'm genuinely confused. You seem to be working with Mizuno, but not Mizuno Tech..?

There will be an official announcement soon

Quote from orsova

Not trying to be difficult, but I'm genuinely confused. You seem to be working with Mizuno, but not Mizuno Tech..?

The confusion is understandable. To be clear this statement is correct. It will all be clear when the official announcement is made.

Quote from Daniel_G

It’s quite simple actually. It’s simple a titanium double walled box filled with ceramic insulation to prevent the walls from collapsing and then removing the air with a vacuum pump to further reduce heat flow.

the ceramic insulation will have a large outgassing. Is the gasses from the ceramic insulation exposed to the active metal (nickel or whatever you have)?

Quote from j9381

the ceramic insulation will have a large outgassing. Is the gasses from the ceramic insulation exposed to the active metal (nickel or whatever you have)?

or may use something like that:

Properties of Macor | Morgan Technical Ceramics

MACOR^® Machinable Glass Ceramic (MGC) has a continuous use temperature of 800^oC and a peak temperature of 1000^oC. Its coefficient of thermal expansion readily matches most metals and sealing glasses. It is non-wetting, exhibits zero porosity, and unlike ductile materials, won't deform. It is an excellent insulator at high voltages, various frequencies, and high temperatures. When properly baked out, it won't outgas in vacuum environments.

As the titanium box is double-walled out-gassing is perhaps not an issue. I think a Macor box would be very expensive.

Quote from Alan Smith

As the titanium box is double-walled out-gassing is perhaps not an issue. I think a Macor box would be very expensive.

true... , therefore keep it small and simple!

As Alan says outgassing isn’t an issue. We are just reducing the gas pressure inside the VIP to reduce kinetic energy transfer between the walls. There are more exotic materials available such as aerogel insulation but that’s overkill in this application.

Quote from Daniel_G

As Alan says outgassing isn’t an issue. We are just reducing the gas pressure inside the VIP to reduce kinetic energy transfer between the walls. There are more exotic materials available such as aerogel insulation but that’s overkill in this application.

the surface area of ceramic fiber insulation with plastic binders is enormous and will outgas (any ceramic fiber insulation having stiffness has some plastic binders), the fact that you say it's a double wall means these gases are not exposed to your active material (nickel?).

It may not be worth the aggravation to put a vacuum in those titanium panels - because of outgassing and risks that the panel insulation coefficient will change - this is just a gut feeling.

It's important to make sure the calibration experiment matches the active experiment as much as possible. I had a situation where I used more nickel mesh in the active experiment compared to the calibration experiment. It was probably twice or three times the amount of nickel mesh in the active experiment compared to stainless steel mesh in the calibration experiment - plus the mesh opening size was smaller in the active experiment compared to the calibration. As result, the average temperature was something around 10 C colder for the active experiment compared to the calibration experiment at the same power level (and thus this was a failed reproduction). I attribute the colder temperature to the amount and size of the mesh being different between the active and calibration experiment (and no excess heat) which redirected the heat flow to other parts of the calorimeter and away from the thermocouples, there were 10 thermocouples on the outside of the vessel.

I assume you will base your excess heat on the thermocouples in the hottest areas right next to the active vessel (i.e. the center of the insulated box). I would say small amounts of excess heat could be due to differences between active and control experiments. But if you get a big result, then it is more likely real. My initial assumption is the insulation you use around the vessel will minimize any problem with the control being different than the active. I did not have insulation around my vessel.

All valid points. It’s not a hard vacuum in the panels, normally between 50 and 100mbar. Yes the innermost section is where the temperature is measured. Also calibration runs are done both before and after the active run so any effect of outgassing would become apparent between the two calibrations.

Paper comparing panels made of various materials.

Edify and enjoy.

Could you describe more about your paper ?

In my current job, i'm in charge of the cell/module assembly lines studying/manufacturing.

In this way to do a stack we stick between each cells a thermal insulator.

A day, i cutted this aerogel layer to see inside only very fine powder, so why some powders are used in this way ?

Quote from nickec

Paper comparing panels made of various materials.

Edify and enjoy.

Quote from nickec

Paper comparing panels made of various materials.

I had to download the paper to see the tables correctly formatted - otherwise it can be confusing especially table 7 which made little sense otherwise.

https://www.degruyter.com/document/doi/10.1515/secm-2013-0162/pdf

In table 7, the thermal conductivity of the panels at atmospheric pressure is 3 to 5 times the thermal conductivity at 1 mbar (i.e. 1/1000 of an atmosphere).

The question is: What is the thermal conductivity change after the core insulation outgases? I think there is risk it could be as much as 5% or 10%.

You say that you will verify the calibration constant using a dummy cell before and after the active cell to confirm that the calibration has not changed. Prior to any calibration run, you may want to bake the fully finished vacuum panels at some high temperature so as to get the outgassing and whatever else out of the way so that your calibration constant changes the least during experimentation. You could even run the calibration before and after this bakeout to see any changes.

Yes I think it probably makes sense to do a bake out at maximum operating temperature and then reapply the vacuum. I’m not sure how much vacuum we can apply before the titanium box starts to collapse with the ceramic wool inside. They is why I was considering just about 50mbar maximum vacuum so any possible outgassing should result in a minimal increase in heat transfer, but the overall thermal conductivity will be higher but the variation will be minimal. We will have to see but as I want to remove any source of variability more than achieve the best possible vacuum. I agree as we move forward and we start to aim for infinite COP operation then minimizing thermal conductivity will be a higher priority.

I feel I must point out I am NOT an Author of the Paper I shared.

Quote from Daniel_G

They is why I was considering just about 50mbar maximum vacuum so any possible outgassing should result in a minimal increase in heat transfer, but the overall thermal conductivity will be higher but the variation will be minimal. We will have to see but as I want to remove any source of variability more than achieve the best possible vacuum.

As far as a mechanical structure is concerned the the difference between 50 mB and 0 mB is just 5% more load. It might be more significant at the kind of temperatures you want to reach.

This is for the common Ti6Al4V alloy. See also...https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/Ti%206Al-4V.pdf

Thank you Alan. Ideally we will want to reduce the pressure to about 1mbar if this doesn't introduce additional variability which we definitely want to avoid. Its very helpful to have these discussions here. We are planning to use commercial grade 2 Ti sheets.

Quote from Daniel_G

Yes I think it probably makes sense to do a bake out at maximum operating temperature and then reapply the vacuum. I’m not sure how much vacuum we can apply before the titanium box starts to collapse with the ceramic wool inside. They is why I was considering just about 50mbar maximum vacuum so any possible outgassing should result in a minimal increase in heat transfer, but the overall thermal conductivity will be higher but the variation will be minimal. We will have to see but as I want to remove any source of variability more than achieve the best possible vacuum. I agree as we move forward and we start to aim for infinite COP operation then minimizing thermal conductivity will be a higher priority.

This is not a solution because it will just outgass again - you have to bake the panel *after* the final application of the vacuum.

In other words, the bake out is the last step in manufacturing the panels, not applying vacuum.

I hope, this is the right spot to ask some more specific technical questions on reactor design. However, I (we) are not doing an exact MIZUNO replication, but similar.

I would be pleased, if we could have an exange here, since I believe participants in this thread have similar technical challenges. Otherwise please mods advice the best thread.