Hi everyone,
I’m working on a natural ventilation study using Honeybee + Airflow Network (AFN) in Grasshopper, and I’m trying to model two different types of operable openings within the same room:
- Windows (main openings)
- Ventilators with 20×20 SS insect mesh (reduced airflow)
Goal
I want to:
-
Assign different airflow properties to windows and ventilators:
- Windows → higher operability (e.g., frac_area_operable ≈ 0.5, Cd ≈ 0.6)
- Ventilators (mesh) → reduced airflow (frac_area_operable ≈ 1, Cd ≈ 0.55)
-
Use AFN to simulate cross ventilation + stack effect
Current Workflow
-
I create apertures separately:
- Windows → HB Aperture
- Ventilators → HB Aperture (with default construction)
-
Then I add them to rooms using HB Add Subface
-
Then I try to use HB Window Opening to assign ventilation properties
Problem
The HB Window Opening component takes Rooms as input, not apertures.
So once both windows and ventilators are added to the same room:
- I can only assign one set of opening properties
- I cannot differentiate between window vs ventilator airflow behavior
My Questions
-
What is the correct way to assign different AFN opening properties to different aperture types (e.g., windows vs ventilators) within the same room?
-
Is there a recommended workflow to:
- Filter apertures (by name/type)
- Apply different opening settings
- And recombine them into a single HB Model?
-
Alternatively, is this something that requires:
- Custom AFN components (SimpleOpening / DetailedOpening)?
- Or a different approach entirely?
Context
- Project: Anganwadi building in Odisha (naturally ventilated)
- Ventilators use 20×20 stainless steel mesh, so airflow needs to be reduced compared to windows
- Using AFN for more accurate airflow modeling (wind + stack)
I’ve attached screenshots of my current Grasshopper setup for reference.
Any guidance on the correct workflow would be really helpful.
Thanks in advance!
Anganwadi_detailed_final.gh (1.4 MB)