In your case, your interest is effectively to combine strong thermal resistance and strong thermal inertia; in theory, it is the wood wool that comes out winning, in my opinion before the wool of sheep; but cellulose wadding is not bad either. As for the polyurethane, it is certainly the worst ... The straw would not be bad either if it were its mediocre properties in terms of thermal resistance ...
I especially think that the solution to your problems lies mainly in the design and use of your home, and not in the only wall structure. Attempts to add internal inertia (walls of partitions, wood structures, furniture) and plan a serious management of cooling and ventilation periods; especially limit in the summer period the solar contributions, formidable for the houses with light structure, and imperatively to be evacuated. This is much more important than the dephasing histories of materials ...
The thermal phase shift what is it ???
Re: The thermal phase shift what is it ???
So, if I understand correctly, you have a heat input through the window of the chassis and you only want to limit the losses thanks to an insulation of the opaque walls ...
You write:
No, what is insulating is the trapped air, so materials containing a lot of air are much better than a convected air space ...
You write:
This would mean that the 6cm partitions would be more insulating empty (knowing that one should not rely on a total waterproofness of these partitions that are made of wood by me) that with straw, sheep wool or polyurethane?
No, what is insulating is the trapped air, so materials containing a lot of air are much better than a convected air space ...
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Re: The thermal phase shift what is it ???
AD 44 wrote:I still do not really understand what you want to do ...
A chassis, a greenhouse ???
I have the feeling that your heat stock will be that of the earth, right? Once this one heated the day under the trunk by greenhouse effect, it is then necessary to slow the thermal exchanges with the surrounding air but also and especially with the surrounding cold land which it was not heated under the trunk.
You have to find a way to isolate not only the trunk itself, but also the deep ground on the periphery of your frame, cork plate (or extruded poly or other ...) descending vertically in the ground in line with walls of your chest ...
A small diagram, or a sketch even freehand of your project?
Here is an illustration in use (there it was empty of course)
Disregarding bottles is not the subject (for the moment)
attention on the photo it lacks the frame / lid / window (which is not a glass but it is to illustrate)
So as in all things there is the ideal and what I can or want to do.
As for touching the ground in its depth it is niet.
On the other hand it is clear that the bottom of the chests was lined this winter and will be again, with hay in this case.
As Didier and Raimondo said it is necessary to slow the escape of the night heat accumulated by the ground during the day.
And in this case it is a blanket facing alu to the ground that would be best provided that it retains its utility posed over the chassis.
It remains to know what I put in my 6cm wall thickness and that has the "good" lambda and phase shift and tutti quanti
Last edited by Adrien (ex-nico239) the 28 / 07 / 19, 22: 52, 1 edited once.
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- Adrien (ex-nico239)
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Re: The thermal phase shift what is it ???
bardal wrote:In your case, your interest is effectively to combine strong thermal resistance and strong thermal inertia; in theory, it is the wood wool that comes out winning, in my opinion before the wool of sheep; but cellulose wadding is not bad either. As for the polyurethane, it is certainly the worst ... The straw would not be bad either if it were its mediocre properties in terms of thermal resistance ...
I especially think that the solution to your problems lies mainly in the design and use of your home, and not in the only wall structure. Attempts to add internal inertia (walls of partitions, wood structures, furniture) and plan a serious management of cooling and ventilation periods; especially limit in the summer period the solar contributions, formidable for the houses with light structure, and imperatively to be evacuated. This is much more important than the dephasing histories of materials ...
Attention it is not at all a house .... see photo above this post ....
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Re: The thermal phase shift what is it ???
Ahmed wrote:So, if I understand correctly, you have a heat input through the window of the chassis and you only want to limit the losses thanks to an insulation of the opaque walls ...
You write:This would mean that the 6cm partitions would be more insulating empty (knowing that one should not rely on a total waterproofness of these partitions that are made of wood by me) that with straw, sheep wool or polyurethane?
No, what is insulating is the trapped air, so materials containing a lot of air are much better than a convected air space ...
Uh, I'll try to understand but before that a precision on the meaning of the words
chest = it is the parallelepiped of wood (cf photo above)
chassis = it's the cover, the cover, which was often a glass actually
So yes I have a heat input by the frame / window / and in this case sandwiche P30 / greenhouse tarp
It must therefore heat up a maximum (which is usually the opposite of what is recommended for homes, so a minimum phase shift (if I have forgiven) but only for HEAT to return as soon as possible .
Conversely it is obvious that I want the cold penetrates as late as possible so the maximum phase shift (if I did not understand) for the cold.
Which is perhaps impossible elsewhere ...
Ok for the air trapped in the material
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Re: The thermal phase shift what is it ???
For me, chest or chassis are synonymous and designate the whole ... But it does not matter ...
No, the cold does not penetrate, it only occurs a heat exchange between two environments of different temperatures, all tending to balance ...
No, the cold does not penetrate, it only occurs a heat exchange between two environments of different temperatures, all tending to balance ...
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Re: The thermal phase shift what is it ???
Ahmed wrote:For me, chest or chassis are synonymous and designate the whole ... But it does not matter ...
No, the cold does not penetrate, it only occurs a heat exchange between two environments of different temperatures, all tending to balance ...
Ok for the accuracy ...
It remains to (if it is possible) to privilege the incoming hot and to discriminate the incoming cold or to privilege as much as possible the conservation of the hot one.
For the chassis it is pegged it is layer face aluminum inner side (if its action is effective in frame cover mode)
For walls ... the question remains.
Well the manufacturing will soon begin but there is no fire either since there will be comparative: straw, sheep and .... X
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Re: The thermal phase shift what is it ???
Put this notion of phase shift aside ... It will be less confusing.
Think: capture (glass), storage (mass and soil inertia), insulation (heat preservation)
Think: capture (glass), storage (mass and soil inertia), insulation (heat preservation)
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- Adrien (ex-nico239)
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Re: The thermal phase shift what is it ???
AD 44 wrote:Put this notion of phase shift aside ... It will be less confusing.
Think: capture (glass), storage (mass and soil inertia), insulation (heat preservation)
Ok ac you all understood ....
If I spoke about it it's because each time you look at the qualities of an "insulating" material (in the broad sense) the comparatives always advance these figures ....
But capture - storage - insulation suits me perfectly provided they always prefer the hot.
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Re: The thermal phase shift what is it ???
If it's braking the cold entrance yes
If it's braking the entry of the hot no
If it's braking the exit of the hot no
If it's braking the exit from the cold no
There is a perfect analogy between the thermal resistance and the electrical resistance: the electric resistance brakes the electron current in the same way, whatever the direction of the current.
* What determines the direction of the current: it goes from the high potential down to potential
* What determines the direction of heat flow: it goes from high temperature to low
Thermal resistance will do the same, so what you want is impossible. By cons (it becomes complicated, but achievable), we can consider the most insulating walls possible, and add a ventilation system controlled by thermostats, and / or an internal heat source, or even a reversible air conditioning according to the expected strategies.
This would mean that the 6cm partitions would be more insulating empty (knowing that one should not rely on a total waterproofness of these partitions that are made of wood by me) that with straw, sheep wool or polyurethane?
that's the question at 1000 €
yes theoretically the air is the best insulator, but provided that there is no convection in the air gap ... Gold from 2 or 3 cm, it begins to swirl and we are no longer under the assumption of a static air. The regime becomes conducto-convective and at that moment, instead of being an insulating agent, the air becomes a carrier, a player in the heat exchange..
To prevent convection, the easiest way is to have foams or small cells in the air space. The thin insulation is not bad too because it mouth 2 3 cm by its presence.
Even more theoretical, the top of the top would be the vacuum, but it poses technical problems (mechanical strength at atmospheric pressure and possible leakage by aging or degradation of the cells).
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