Using Wufi to Predict External Condensation

[Sam@inhabit]

Hi All,

We have made a glass material based on the following thread to model external condensation risk in Darwin.

https://www.wufi-forum.com/viewtopic.php?t=162

We are comparing the performance of single vs double glazing in regard to reducing the risk of external condensation in Darwin- see attached wall make up.

Can anyone identify any flaws in this methodology.

Thanks

Sam

[Christian Bludau]

Dear Sam,

for model reasons, in WUFI no dew water can form on the surfaces directly. So to calculate the amount dew-water on a surface, you will need to insert a layer, which can store the water. You need a layer which can store some water (high porosity) and it should not highly influence the transport properties from the ambient conditions to the surface. For example 1mm of air layer (with the short name) would be usable.

Please also note, that the following parameters will highly influence the amount of dew water:

• long wave radiation (the climate file has to contain the atmospheric counter radiation as exact as possible)

• short wave absorption of the surface

• long wave emission of the surface (the emission will change to about 1 with the increasing amount of dew water. WUFI can not take that in account directly. So it may make sense to have a closer look on time spans with dew water by performing further calculations with changed long wave emission of the surface)

Christian