Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?

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Christophe
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by Christophe » 27/01/23, 22:51

SebastianL wrote:I don't see the point of putting > 1mm of wax. The thinner it is, the more it is able to take on a domed shape to absorb the volume of water that descends and the volume of vapor created by the descent of the roof.


The interest is to create a homogeneous surface of wax: seeing the bowl of wax with holes with only 1.5 mm...1 mm is not enough to distribute the liquid wax well over the entire surface...

In short, I wonder why I break my ass making a video if no one is watching it… : Shock: : Shock: : Shock:
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by A.D. 44 » 28/01/23, 00:33

sicetaitsimple wrote:But personally, during my few professional experiences, I have never seen an exchanger whatever it is better or as much exchange when it was dirty as when it was clean .....


Well, that was the only point of my comment.

Well...it turns out that I'm not a professional at all.

My comment is therefore probably worthless.
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by SebastianL » 28/01/23, 05:07

Christophe wrote:
SebastianL wrote:I don't see the point of putting > 1mm of wax. The thinner it is, the more it is able to take on a domed shape to absorb the volume of water that descends and the volume of vapor created by the descent of the roof.


The interest is to create a homogeneous surface of wax: seeing the bowl of wax with holes with only 1.5 mm...1 mm is not enough to distribute the liquid wax well over the entire surface...

In short, I wonder why I break my ass making a video if no one is watching it… : Shock: : Shock: : Shock:


It's curious I didn't have this distribution problem at all when I did my test from boiling water, in the bottom of a light box : Cheesy:
I had 1.5mm of wax all over.
I admit I didn't catch the fried egg design, was it a simulation of the ozone layer? In addition it was not transparent like me, do you have a low cost Chinese wax? I have 500gr blocks that I buy in stores, maybe the product is pure (100% Chinese)
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by SebastianL » 28/01/23, 05:24

sicetaitsimple wrote:
SebastianL wrote:The thermal conductivity of liquid paraffin is low (0.152 W/mK)
The thermal conductivity of solid paraffin is low (0.2 W/mK)
The thermal conductivity of liquid water is lower (0.6 W/mK)


Christophe 3 posts above: "And Seb answered the question: liquid wax exchanges heat better than water."
Who to trust? : Shock: : Shock: : Shock:


Damn then we can not correct his mistake discreetly!
I was fooled by the latent heat of fusion, because in practice wax burns the skin mega better than water.
Once I burned myself a little with a technical wax that melts at 105°C, boiling water is warm piss
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by Obamot » 28/01/23, 06:41

SebastianL wrote:The thermal conductivity of liquid paraffin is low (0.152 W/mK)
The thermal conductivity of solid paraffin is low (0.2 W/mK)
The thermal conductivity of liquid water is lower (0.6 W/mK)
Extruded polystyrene (XPS) offers very strong thermal performance which varies, depending on the blowing agent: from 0.035W/(mK), for standard thermal performance (recycled CO2 blowing agent) to 0.029W/(mK) for higher temperatures (blowing agent: HFC gas).
we are therefore in a ratio of 7x.

I continue the reasoning - without wanting to influence a choice already made eh, it's just to go to the end of the logic (to understand my 'errors'), and leaving aside the real usefulness of such a device, which has a very low cost for performance 6 to 7x higher than that retained — for a simple reason: the inter-seasonal storage at shallow depth (with a thermal water tank) is studied by the engineers of the ETHZ have developed such devices in building foundations themselves (so it's not trivial) and more with drilling at (-)400m (although Swiss depth mapping is progressing well for this other component of the energy mix of the near future)

I reviewed the video, it indeed proves that it will be VERY difficult (in principle impossible) to guarantee a uniform thickness on the surface over a constant of at least 1,5mm with wax or paraffin with a ∆⁰ of 50⁰C (annual fluctuations between 20⁰C and 70⁰C).

From what I understood with the finger* :D — after my self-criticism of the insulating false ceiling with a fine layer of intermediate air — it is that this device is not as perfect, insofar as evaporation could nevertheless take place... and we could argue that the loss could be done in one way or another via this air gap. The problem is that I had thought about it, but until then I had been reluctant to put SPX panels in direct contact with moisture, although the material was hydrophobic by nature (the expert offices had put evidence in the past, an erosion of the PE submitted after a few decades...)

And there the super simple technical solution exists: make "waterproof the SPX, it exists.
TECHNO BOND 3056 is a two component, 100% solid polyurethane elastomeric adhesive. It is a thixotropic liquid which has a long pot life and an elongation rate of 300%. This adhesive is widely used in the assembly of different substrates such as natural and synthetic rubbers on metal, concrete, plastics, wood and composites. This adhesive is also a waterproof adhesive that has very good heat resistance.

FEATURES
Water-proof
Easy to mix
Resistant to large temperature changes
Thixotropic
Effective wetting of surfaces
User-friendly
Rapid polymerization
We can now waterproof the SPX, so all you have to do is waterproof these grooved-ridged panels, stick them to the wall with polyurethane foam (it sticks very well to everything and especially to the SPX)
suddenly it's airtight and no more evaporation... Problem solved.

https://www.usimm.ca/comment-durcir-et- ... styrene-2/

* (because a strange custom here would like it to happen that we get set on fire without saying why)
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by Christophe » 28/01/23, 10:42

SebastianL wrote:It's curious I didn't have this distribution problem at all when I did my test from boiling water, in the bottom of a light box : Cheesy:
I had 1.5mm of wax all over.


With boiling water it is possible that the repair will be done better but I tried to simulate the gradual rise of my tampon... which never muddies.

SebastianL wrote:I admit I didn't catch the fried egg design, was it a simulation of the ozone layer? In addition it was not transparent like me, do you have a low cost Chinese wax? I have 500gr blocks that I buy in stores, maybe the product is pure (100% Chinese)


I don't know what it is but it's not smooth at all : Cheesy:

These are tealight candle holders from Action…made in Belgium…no idea of ​​the composition…

ps: Obamot you go out on the corner punished! : Mrgreen:
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by dede2002 » 28/01/23, 10:57

dede2002 wrote:
Christophe wrote:...
Maybe there is no air intake simply because the pressure drops and the diameters of the pipes are sufficient for the water to fall under the action of gravity?
...


How could water sink if its volume is not compensated with air?

...


In fact, since the height is 12m. the water is forced to drop again by about 6 ms if there is no air entry. The top part would be steam under vacuum...? (12m = 1.2 Bar, impossible in depression).
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by Christophe » 28/01/23, 11:22

Didn't understand your calculation 6 ms?

The pressure gauge at the outlet of the pump (bottom) in operation is indeed at 1.2 bars…

The water level is about 1m lower than the pump.

So the fall is more like 13 m…
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by dede2002 » 28/01/23, 11:24

6 meters is approximately the maximum pumping (or siphoning) height on the suction side. Above the depression is too strong and the water evaporates.
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by Christophe » 28/01/23, 11:26

Yes that I know it's the NPSH but I don't really see the connection with my concern…can you rephrase?
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