WUFI pro vs Glaser

[nelkov]

I have the following problem.
I am trying to compare the results from WUFI Pro and Glaser method.
I know that they cannot be the same but at least have to be closer.

First I am trying to obtain the results from single-layered constructions:

AERATED CONCRETE - 600 kg/m3 - d=20cm :

Calculation Time: 1 year

Moisture Storage function - Generated
Liquid transport coefficients - Generated

Excluded Capillary Conduction
Included Heat and Moisture transport

Surface Transfer Coefficients:
Heat Resistance for Exterior Surface: 0,04
Heat Resistance for Interior Surface: 0,13
Sd-value: No coating.

Initial temp: 20
Inital RH: 0,8


Climate:
Indoor: constant temp 19
constant RH 0,65
Outdoor: constant temp -10
constant RH 0,90

After calculations:

Total Water Content: Start - 3,4 End - 7,06

Total Water Content = 7,06 - 3,4 = 3,66 kg/m2

When i solve this with Glaser method for one year i obtain:

Total Water Content - 1,11 kg/m2

According to me and my supervisor of the Phd thesis it is a big difference and i don't know if i miss something.

I have done this with other hygroscopic materials and there is also a big difference.

I know that hygroscpic materials have parameters like Moisture Storage Function and Liquid Transport Coefficients and others which influence the results. But I think there is a way they can be compare.

Is it better comparison would be if you create a new material without Moisture Storage Function and without the some other parameters but only those which concern Glaser method or it is impossible to model such case.

[Christian Bludau]

Dear Nelkow,
the problem here is, that the adsorption of the materials is not taken in account in glaser. Further glaser should not be used for hygroscopic materials. As WUFI takes in account the adsorption in the materials, the comparison makes not much sense.
Please also note, that you should only have a look on the last year, after the construction is in its steady state. If you just subtract start and end water content, you take in account some redistribution happening on the way to steady state.
Christian

[nelkov]

Set Moisture Storage Function 0 and Liquid Tansport Cofficients to 0.
Set constant climate conditions:temp and RH for inside and outside and calculation time equals to condensation hours according to Glaser.
Exclude Capillary conduction.
Set material Initial temp 20 C and RH=0.

Is this enough to stop liquid redistribution in the material or there is other processes which influence on the liquid redistribution and cannot be excluded.

Also is there any way to obtain how many condensation hours have the material for 1 year and calculate accumulated condense water and after that solve this with glaser for these condensation hours.

[Christian Bludau]

How do you take in account the dew and evaporation period?

We also have an howto for the dew-water in transient calculations, but unfortunately at the moment it is only available in German:
https://wufi.de/de/wp-content/uploads/s ... ertung.pdf

[nelkov]

According to pdf the results for accumulating condense water obtained from 1 cm separated layer from mineral fiber is compared with 1000 g/m2. But this is for 1 cm not for whole mineral fiber. Is this correct? And then a comparison is made for 1mm thin layer to see the accumulating moisture at the contact zone between mineral fiber and the first layer.