Can Honeybee/Ironbug simulate Passive Downdraft Ventilation?

I’ve been asked whether I could make an assessment of a passive downdraft ventilation system and I’m not sure where to start and whether Honeybee can even do this - it looks like a pretty niche application:

(note the above isn’t the actual building design, just a reference diagram I found online)

I’m thinking I’d first have to run an outdoor CFD model to get the wind pressure coefficients at the openings, then use the Airflow network to simulate the interzone airflow. Not sure how to include those cooling coils though - is this something that Ironbug could do?

Ah, smart arrows! I haven’t seen those in a while.

You can always use the AFN to model flow from room to room and it can model buoyancy-and wind driven driven flows like what the author of that diagram is imagining.

It looks like the whole system is relying on running a cooling coil in those towers so you’ll have to put the setpoint lower in those rooms and condition them somehow. And then you can see if it works.

I have a sense that these types of systems usually require an exhaust fan at the top of the atrium to get the flow to work but, in this case, I guess all of the work is being done by that cooling coil. The cooling coil probably uses more energy than an exhaust fan and is harder to control but I guess it can help with humidity control. I haven’t yet added exhaust fans into honeybee-schema but it is on the agenda:

In the meantime you can add them with a measure or some custom editing of the OSM.


Someone else called them Magic arrows, which i think is more appropriate.

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