Using the AirFLowNetwork in single sided models

asked 2024-09-06 06:54:33 -0600

kostas
61 ●2

updated 2024-09-06 13:43:23 -0600

Aaron Boranian

14250 ●86 ●24 http://bigladdersoftware.com/

Hello there,

I'm modelling a single-vented flat in EnergyPLus using the AFN. The flat has only one wall ( with two windows on it) exposed to outdoors;

Hence, the three surfaces (the wall and two windows) have the same WindPressureCoefficientValues object.

When I run the simulation, I get the following severe error:

The same Wind Pressure Coefficient Curve name is used in all AirflowNetwork:MultiZone:ExternalNode objects.
Please input at least two different Wind Pressure Coefficient Curve names to avoid single side boundary condition.

What does this mean? Does it mean that somehow the air entering the flat must be exhausted to outdoors?

Regards,

Kostas

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Comments

If all 3x nodes share the same Cp curves, there could be no wind pressure driven ventilation. Maybe try single-sided ventilation? Otherwise:

Try copy/pasting (2x) that single curve object, rename both copies to ensure uniqueness, then have all 3x ExternalNode objects each reference a unique curve individually (one-to-one match)
If unsuccessful, maybe slightly change the values (to the 3rd decimal?) to ensure 3x unique curves