RE: [EnergyPlus_Support] Modeling horizontal opening in the floor of a building (related to outdoor condition)

For high ceiling spaces, where cold air comes in at the bottom and warm air leaves at the top and only the occupied space must be kept at setpoint (this means the thermostat is positioned lower at occupancy level, I would model all the connected space as 1 zone and change the roomair model to the 3 node displacement type.

If there is a very large floor plate with a hole from a staircase, I would model 2 zones with a very thin clear window to represent the hole. Then link the zones with an air exchange. The hard question is what is that air exchange.

Let's expect that some cold supply air from the above level will fall from the ceiling to the floor, flow along the floor before it gets warmed up and spill down the hole over the hole's outer edges. Replacement air will migrate from the warm zone air below and flow up through the center of the hole.

If the supply air is not cold enough, or the supplies are far from the hole, the effect will be far less. Worst case is that the ankles level air is at say 24 C and the ceiling level air of the zone below is at say 26 C, then the density difference may be very small. The resulting air exchange may be negligible (air doesn't carry much energy...at least not at â??T=2 C).

roughly equal to the sum of the cold air supply volume flow rates within 2 meters of the opening. The assumption is

On 25 Nov 2015 10:14 am, "MN mneves32@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

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Hi,

What is you unconditioned zone? What are your objectives with this zone?

Mn
From: fati_tilak@xxxxxxxxx [EnergyPlus_Support]
Sent: â??11/â??25/â??2015 7:18
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Modeling horizontal opening in the floor of a building (related to outdoor condition)

Â

Hi,Â
Would you please help me to model an opening in the floor of a building. I have a building with 2 zone : conditioned and unconditioned. unconditioned zone have a large opening in its floor. definitely it is a horizontal opening. for modeling this opening, First I decided to increase the number of "Air change per hour" to a very high number for example 100. and set an schedule that is always "on".Â
After a while, based on a friend's advice, I tried to model this opening as a door that is always fully open. I added an object in "Airflow Network: Simulation Control" , Â "Airflow Network: Multizone: Surface" and " Airflow Network: Multizone: Component: Horizontal Opening" group. But, I understand that "Airflow Network: Multizone: Horizontal Opening" is assumed for horizental interzone surface. Â whereas, my opening is not. it is related to outdoor air not another zone.Â
Now, I have no idea what should I do whit this opening !.
Â I really appreciate if you can share your knowledge in this field and help me to solve this issue.
Thanks in advance.
TilakÂ
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