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 » 26/08/21, 01:07

yes ... I had cut bottles but I changed my mind to observe the condensation on the walls initially and to be able to study the stability of the products in closed aqueous environments ... since it is roughly the final goal ...

After 6 days we can already see that some products are neither chemically stable nor effective in combating evaporation ... it was a first selection, only LHM seems relevant to me for the moment.

For the concrete tank, this will be done with the selected product ... I have a container of sikaflex still sealed ...
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by humus » 26/08/21, 15:51

and no way to stick something waterproof to the ceiling (plastic film), or to brush the foundation with tar, or other water repellent?
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by Obamot » 26/08/21, 21:07

Tar is great because it is water repellent.

The problem is that water is a SOLVENT, and contrary to what one might think, a fairly powerful solvent.

And we have extremely reactive and unstable oxygen on the surface. What a cocktail ...

This is why hydrocarbons (and all fatty substances) disintegrate in the presence of these elements which preside over absolutely all possible (bio) -chemical reactions. A swimming pool, which is moreover heated, is a breeding ground for opportunities for chemical reactions of all kinds.

I'm not amazed at all these reactions in the bottles, it was highly predictable. Without being too mistaken, I think that at the end of the chain, whatever the fatty substance used, all the reactions will have liquefied and emulsified absolutely everything that is on the surface. Over time, all that will remain is shaggy, floating deposits, the rest will flow to all the walls with the heat, including those of the glass tubes of the collectors (or for the rest, will fall to the bottom ...)
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by humus » 27/08/21, 07:11

On reflection, if it is complicated for Christophe to act on the interior ceiling of the tank, we can act on the exterior face.
I again suggest painting or spraying a water-repellent product on this outer face.
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by GuyGadeboisTheBack » 27/08/21, 13:43

If I were Christophe, I would avoid putting any product like oil or worse LHM in his tank, it would be irreparably polluted and in the event of an essential repair to come, it would be a real hassle to clean everything ...
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by Christophe » 27/08/21, 18:23

There is no question that I do heavy work!

I think the slab is already water-repellent otherwise I would have condensation everywhere under the insulation board ... I only have it at eye level!

Well I did a weigh-in 1 week later ...

The control bottle only lost 10g (out of 141g) it is therefore not enough for it to be significant so I continue the experiment ...

What I can already tell you: a mystery oil and the LHM are at 0 loss ... the others have lost between 8 and 15 g

The bottle that lost the most by evaporation .... the polystyrene balls (15 g on 131g)... the capillarity has therefore increased the exchange surface as we had predicted ... we know the rest ...

Shit weather there were only 3 days of sunshine and no high temperatures ...
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by phil59 » 29/08/21, 20:08

I haven't read everything, but are we sure that the biggest evaporation takes place in the flask, and not in the aerial part?
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by GuyGadeboisTheBack » 29/08/21, 20:15

phil59 wrote:I haven't read everything, but are we sure that the biggest evaporation takes place in the flask, and not in the aerial part?

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




by phil59 » 30/08/21, 13:07

Second reflection.

When using a balloon, the water heats up, and takes up more volume.

We compensate for that either by water which goes out to lower the pressure, or we put an expansion tank.

With this volume there, the size of the vase ... I can't imagine.

Or, we consider it as an open expansion vessel, as in the past ...

But inevitably, there is a loss of liquid, directly or indirectly.

It remains to be seen, if 100L of loss per year is normal, or it is much less, or, enormously more.

Completely filling "the pool" is not a good idea, in my opinion.

If there is 20-30cm from the "ceiling", it may be "normal" use ???????

The more we fill, the greater the pressure will be when it heats up, and the more we risk micro leaks ...

It's an idea, like that ...
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Re: Thermal buffer: avoid surface evaporation of hot water with oil or other blocking product?




by sicetaitsimple » 30/08/21, 13:29

phil59 wrote:The more we fill, the greater the pressure will be when it heats up, and the more we risk micro leaks ...

No, the "swimming pool" is at atmospheric pressure. On the other hand, "microleaks" on the air circuit (sensors and associated plumbing), I mentioned above, it is a possibility.
You should read everything again, it is true that it is an "extraordinary" installation!
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