Frigolite what value K insulation?

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jeanluc55
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Frigolite what value K insulation?




by jeanluc55 » 29/06/10, 12:47

Hello,
Can someone give me the insulation "K" value for the 30mm thick frigolite? I searched ... in vain, but I'm really not a specialist on the web !!!!

I had a veranda renovated and part of the roof is made up of "thermotop" style panels which would seem to have a "K" coefficient of 0,8 but in frigolite it would surprise me if this coefficient was reached.
Thanks to the specialists.
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by Christophe » 29/06/10, 12:55

Hello,

Frigolite = expanded polystyrene = average 0.04 of lambda according to https://www.econologie.com/isolation-lam ... -3478.html

For 3 cm thermal resistance = R = thickness / lambda = 0.03 / 0.04 = 0.75 = K = close to 0.8

The problem is that there is a lot of type of expanded poly:

EPS ref. AM 0.058
EPS ref. BM or CM 0.047
EPS ref. Or CC 0.043
EPS ref. DM or DC 0.041
EPS ref. EM or EC 0.039
EPS ref. FM or FC 0.037
EPS ref. GM or GC 0.036


So there may be 60% difference in performance ...

ps: https://www.econologie.com/forums/search.php : Idea:
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by jeanluc55 » 22/07/10, 05:32

Hello Christophe,
after a long absence, I allow myself to return to your calculation.
I had indeed another answer than yours with the same coefficient lambda.
The attached formula is the following: to calculate the U (heat transfer coefficient of the wall) here is the formula

U = 1 / R where R is the thermal resistance of the wall and is calculated with this formula:
R = d / lambda
where d is the thickness of the insulation in meters (ie 0.032 m for your case) and lambda is the coefficient of thermal conductivity (lambda = 0.038 to 0.040 in principle)

All you have to do is take your calculator:

U = 1 / (0.032 / 0.038) and you have the answer: 1.19

I do not take into account the thickness of the walls that jam the insulation because negligible for the calculation

To get a U = 0.8, you should have, for 32 mm of insulation, a maximum lambda of 0.026 insulation.
But the simple frigolite turns around 0.038 to 0.040. (as a reminder, the smaller the number, the better)

Finally what is the good result?

Thank you for enlightening my lantern, because instead of being fixed I now have a doubt.

Kind regards.
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by Christophe » 22/07/10, 10:15

The 2 are good since R = 1 / U or 1 / R = U

Gold 1 / 1.19 = 0.84 = close to 0.75

The difference comes from the different calculation values: I took 3 cm and 0.04 from lambda and you 3.2 cm and 0.038
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by sspid14 » 22/07/10, 14:35

We must pay attention to the definition we give for R, U and K!

The R c is the thermal resistance of a material. Here, for the expanded polystyrene of 3 cm, R = 0,8 m²K / W.

The U c is the thermal transmission coefficient of a wall made up of 1 or more materials (with or without an air space) => U = 1 / (sum of R). Here, if we consider that there is only expended PS, U = 1,25 W / m²K.

And the K defines the overall insulation of the building (composed of several walls). In Belgium, new construction must respect a K45.
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by Christophe » 22/07/10, 15:22

Quite well that's why I prefer to speak in R exclusively ... like that at least we know what we're talking about ...

sspid14 wrote:And the K defines the overall insulation of the building (composed of several walls). In Belgium, new construction must respect a K45.


What is the precise definition of a KXX building?
Because it's not used in France to my knowledge ...
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by sspid14 » 23/07/10, 00:54

The K of a building is therefore its level of thermal insulation. It takes into account the U of each wall (walls, windows, floors, doors, ...) as well as its area. it also takes into account the thermal bridges at the lintels and thresholds.

To calculate it precisely, I believe that the link below will be more speaking (see page 2 point 4 pdf).

http://www.dinant.be/pdf/pages/7/formulaire-1-.pdf

And even better, there is even the excel file for the calculation:
http://www.energieplus-lesite.be/energi ... 84.htm#top

One of the criteria for having passive house certification is to be K15 level.
It is also said that a low energy house must meet the K30 (but it is not in the norm to my knowledge).
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by chomich » 27/07/10, 21:59

it is not the Kxx that determines the character of a passive house.
it is the consumption (in Kw / m² / year) and the airtightness (0,6 flight under 50Pa) and the resistance to overheating.
the confusion is that the 15 number is the base number for the consumption of a passive house. (in kw / m² floor area and / year)
in reality, a passive house will often have a K lower than 15, but elkle will mostly have a ventilation control and heat recovery equipment that will keep below the limit in need of heating.
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by Christophe » 27/07/10, 22:39

Yes but ... sorry chomich but give a consumption in kW / m² / year is anything ... I'm tired of hearing such salads!

CONSUMPTION It's in Watts.hours and a POWER is in WATTS !! Point bar!

And when we divide 2 times, it is as if we multiply so kW / m² / year = kW.an/m² ... which means ... not much.

5 or 4ieme course I am.

But you probably wanted to say: kWh / m².an ...

Then if you look closely at the docs which define the "K habitation", you will see that the unit is in good condition. W / m. ° K which is a quite SI unit and acceptable for doing a DPE ...

Note:

If 1 <V / AT <4: K = Um x 300 / (V / AT + 2) = [5] x 300 / ([7] + 2)


There we get a K in ... W / m3. ° K ???

There is something that I do not understand ...a standard must have a coherent unit ...

ps: thanks sspid14 for 2 links!

reps: a very efficient DPE unit would be kWh / m².DJU and not kWh / m².an because m ².DJU take into account the climate and the temperature of heating unlike the m².an ...
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by sspid14 » 28/07/10, 01:11

So I rectify my little mistake: a passive house must not respect a K15 (although I've always said that) but it must respect a consumption of 15 kWh / m².year (as +/- announced by chomich)

It must also effectively maintain an airtight 0,6 h-1 (ie air renewal of 0,6 volume / hour) under a difference of 50Pa.

And also a percentage of overheating that must be less than 5%, I think that for that one calculates the time where the temperature exceeds the 25 ° C compared to the time where it is lower.

For the unit of K, I believe that we should not try to understand: the "[7] +2" is already not possible, as we say: we do not add pears and apples.
On the other hand, it is necessary to use the SI in the formula otherwise it works not the same.

For the kWh / m².an, do the DJU (degree.day I suppose?) Do not intervene somewhere?
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