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*
— 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)