Thermal inertia)

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phil88
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Thermal inertia)




by phil88 » 18/11/16, 09:53

Hello everybody
If I understood things well, in housing, it is important to have a good inertia, and to minimize losses with an insulation carried out correctly.
In ITE, it is easy to answer this problem.
In ITI, the problem is more delicate, thermal bridges of the cross walls, lack of inertia.

I find myself in the issue of ITI.
We live on a farm from 1830, and it would be a shame to sacrifice its architecture with an ITE. Could be possible but at what cost?
Not very humid because drained, mid mountain area 500 m.
I am therefore working on the problem of thermal bridges by insulating the cross walls. (Hemp lime dosed at 15% 85% or 250 kg / m3)
these proportions correspond to the hemp brick: manufacturing data: Lambda 0,05 to 0,06. On 10 cm the thermal correction is quite good.
For inertia, this is where my question will be, I use a 1000 L buffer tank at 80 °, returned as needed.

What comparison can be made in terms of inertia?
-ITE with inertia by the mass of the walls
-ITI with inertia essentially obtained by 1000 L at 80 °
If my question is correctly asked ???
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Did67
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Re: inertia (thermal)




by Did67 » 18/11/16, 10:57

While this is more complicated (due to effusiveness - the rate at which heat travels), a first approach is to compare the masses at play.

Thermal inertia is a matter of mass!

You cube your walls, you look for their average density and you have a first approximation.

NB: do not forget your tiles (floors, ceilings) according to their nature ...
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Re: inertia (thermal)




by chatelot16 » 18/11/16, 11:14

the specific heat of water is superior to all other materials

the water in the buffer tank is used with a large temperature variation, while the walls remain at room temperature in the event of external insulation

the comparison is therefore difficult

when the exterior insulation is easy because we do not bother with the aesthetics, the thermal mass of the walls makes a free inertia

when you count on a water tank, you get the performance by the technique: it seems more expensive in total to get the same result ... wanting to keep the exterior facades in their old state is a luxury that ends up being expensive when we count all the side effects

the worst side effect: the limited lifespan of interior insulation ... the risk of trapping moisture

some do not like the aesthetics of exterior insulation, but for me it has the beauty of efficiency
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lilian07
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Re: Inertia (thermal)




by lilian07 » 18/11/16, 17:10

Hello,
The inertia obtained technically by your balloon (even if it is better water capacity but technically difficult to tame) and your ITI is in no way comparable to an ITE and your walls. Small table corner calculation by roughly considering that a mass of stone / earth is 4 times less energetic than water. We obtain with the weight (of a traditional house 'far from your case 2.8 T / m2) of the house say 300 Tons
75 tonnes of water equivalent compared to the tonne we can say that it is a factor of 100 ... if I add the perfectibility of the ITI, the unfavorable technique of the LV and the real weight of the house we may be closer by a factor of 200 to 300 .... so no comparison.

I therefore deduce by going further: is inertia important in ITI?
I tend to say no and more broadly at the risk of making skeptics, I tend to say that thermal inertia is useless whatever the house ...
By extrapolating even more, the important thing is to get the heat when it is needed and today it is possible with ease. The LV must then be used to have this small 24-hour reserve (intermittent source) to better distribute the heat at the right time ....
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Re: Inertia (thermal)




by dede2002 » 19/11/16, 09:13

Hello Lilian 07,

Your table corner calculation is interesting, but you would have to heat the walls to 80 ° to get the "factor 100" ...
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Re: Inertia (thermal)




by lilian07 » 19/11/16, 13:16

I took good care not to speak of temperature because the comparison of a heat capacity of an environment is always understood by degrees and not over a range of exploitation (at least at this level of exploitation).
However, by specifying the set of elements known by phil88, the philosophy would not change and even would indicate a factor> 100 without a doubt (it is the interest of a brief unfavorable excess calculation which allows the details to be amortized for orient themselves immediately on a solution). The purpose of this calculation was to compare the 2 types of storage for which the difference, whatever the operating temperature of the LV for individual heating, will be> 100.
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Re: Inertia (thermal)




by LOGIC12 » 17/12/16, 01:05

Hello, "a farm" ??? continuously inhabited, or rather as a second home?

If it is in a second home or for intermittent use, inertia is rather a disadvantage.

It's hot when you fill the car to leave the weekend ...

inertia is not free heating. A mass is heated, and it must be kept at temperature, even if the insulation makes it possible to limit losses to the outside.
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