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How to model natural cross ventilation with airflow network?

asked 2015-09-29 10:10:35 -0600

Bob Martin's avatar

updated 2015-09-29 11:08:38 -0600

Hi, I intend to modulate a natural cross ventilation in an apartment, through the air flow network. I want it so that the air enters through de north facade windows, crosses the whole apartment (unidirectional) and exits out the south facade windows. I’m considering the apartment as a thermal zone, the pressure coefficients are calculated with E+ and I have the airflow values defined. Is it possible? What airflow network components should I use?

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If the air is leaving through the same zone it enters you might consider Wind and Stack with Open Area

David Goldwasser's avatar David Goldwasser  ( 2015-09-29 10:27:43 -0600 )edit

The air is leaving from another zone.

Bob Martin's avatar Bob Martin  ( 2015-09-29 12:13:20 -0600 )edit

Could you clarify what you mean by "I have the airflow values defined"?

Jason DeGraw's avatar Jason DeGraw  ( 2015-09-29 13:55:15 -0600 )edit

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answered 2015-09-29 13:58:40 -0600

a simple recipe is as follows: specify

  • the zones for natural ventilation via AirflowNetwork:MultiZone:Zone
  • the Surfaces with leakage components (AirflowNetwork:MultiZone:Surface)
  • leakage components [horizontal and vertical openings and cracks] are defined via (AirFlowNetwork:Multizone:Component:* or ...:MultiZone:Surface:Crack) you will need some assumptions or data on air mass flow when opening is closed, discharge coefficients etc.
  • external nodes (AirflowNetwork:MultiZone:ExternalNode) for affected facades, roof surfaces, with associated wind pressure coefficient specs
  • AirflowNetwork:SimulationControl details

With pure natural ventilation, you will not have control over the direction of airflows, in fact there will usually occur flows in both opposite directions. This can be monitored via appropriate output variables.

However, there is the option of using venting controls for zones and openings. As an example, you may find more details here.

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Asked: 2015-09-29 10:10:35 -0600

Seen: 1,415 times

Last updated: Sep 29 '15