IES-VE User Forum

There is some help on modeling a DSF in Chapter 7 of "MacroFloCalculationMethods.pdf". You will need to have multiple levels in the DSF in order to simulate the buoyancy phenomenon driving the flow inside the DSF. You can have one or even two levels per floor of DSF; in other words, if your DSF is continuous and is 5 floors high, with 4 meters floor-to-floor height, you can have the elements either 4 meters high (but not more) or even 2 meters high. If the DSF is quite wide you can split it along its width as well.

I should stress, however, that modeling a double-skin façade is tricky! You will need to calculate MacroFlo internal openings as per the IES guidance, but the most critical aspect will be the wind pressure coefficients, especially if the DSF is full-height across multiple floors and/or if the DSF is used to naturally ventilate a building and/or if the building shape deviates significantly from a rectangular prism. You simply cannot rely on the standard MacroFlo wind pressure coefficients, you will need to go to either CFD or wind tunnel tests to calculate them.

This is the part where the engineer needs to know that just because he can draw it in ModelIt doesn't mean that the model will be an accurate representation of the building physics. This isn't meant to talk down to anyone, I just want to stress that you need to tread carefully, because you'll have your name on it and it isn't straightforward.