How to extract ACH results of naturally ventilated zones?

grasshopper honeybee
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Hello,

I am using honeybee to perform a thermal comfort analysis of a naturally ventilated building model. I want to know how to extract the simulation results of air exchange per hour (ACH) using the airflow network (AFN) option in honeybee. I have already set up the construction sets, program types, internal mass, and natural ventilation parameters for my model. I have also run the Open Studio simulation successfully with the AFN option enabled.

However, I am not sure how to access the ACH results from the simulation output.How can I extract the ACH results from the honeybee simulation using the AFN option? Is there a specific component or formula that I need to use?

Thank you in advance for your assistance.

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Hi, I have the same problem. Have you resolved the issue?

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I don’t think that EnergyPlus has an AFN output in terms of ACH but you can look through all available outputs for your model with the HB Read Result Dictionary. There are a lot of outputs related to the AFN that you can request from E+ using the HB Custom Simulation Output component and the bring into Grasshopper with the HB Read Custom Result component.

At a minimum, you will be able to get the air flows through each of the Apertures in the AFN.

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Thank you. I have tried. But it does not provide any result! Please see the snapshot.

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Screenshot 2026-03-25 at 15.35.38
Screenshot 2026-03-25 at 15.35.381916×1000 88.2 KB

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Try using this variable: AFN Zone Infiltration Air Change Rate

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I am going to evaluate the effect of natural ventilation, not infiltration!

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the component above work for both natural ventilation and infiltration, as said in the link above:

The number of air changes per hour produced by outdoor air flow into the zone from window/door openings and cracks in the exterior surfaces of the zone (i.e. the sum of ventilation and crack flows from the exterior into the zone).