Bauklimatik Dresden Software

Dear Delphin team,

I am simulating a ventilated facade with a 5-cm air gap between the wall structure and the cladding tiles. I created a Source/Sink with the type [AirChange] to specify the air temperature, humidity, and change rate in the air gap. My question is: how can I specify that 10% of the rain flow is reaching the air gap? For this, I would like to simulate two scenarios:

1. The rain is penetrating the cladding through the joints to reach air gap.

2. The joints between the cladding tiles are sealed, but the rain is entering the air gap from the top and water drops are flowing on the surface of the wall structure behind the cladding.

Thank you very much in advance!

Hello,

You have to set a moisture source at the certain position. The climate file for this moisture source must be calculated from the rain flow density normal to the surface. To get this you have two possibilities.
1. create a Delphin project with a wall with the same geometry like your construction you want to calculate (inclination, orientation). The outer layer should have no liquid transport. Here set an output 'FluxRainNormal' to the surface. From this you can calculate your moisture source.
2. make the rain calculation by yourself maybe with Excel. The formulas are according ISO 15927-3 with the following parameters
CR = 1.007
CT = 1
O = 0.8
W = 0.4
The climate file should be a ccd file with the keyword 'WaterSource' and the unit kg/m3s. Because a rain flux is calculated in kg/m2s you have to take into account the thickness of the layer where you want to assign the source.

Two remarks to your scenarios:
1. if you set a rain source to air it can easily create a complete filling of the selected elements. Because air don't have a liquid transport the water can only go out by diffusion. Maybe its better to set the source into the surrounding material.
2. How you want to model this water flow from top to bottom? Once again, the air in our database don't has liquid transport. If you want to model this transport you have to create your own air material with a moisture storage and a liquid transport equation.

Thank you very much!