Effect of a hole in a partition wall

[Julian]

Hi guys,

I have a model with several rooms. Some of the walls have a hole of 100% of the surface of the partition wall. I assumed that by doing this the rooms with such partition wall in between would look like a large open space and would have these consequences: First, the daylight would be able to pass from one room to another through the hole. Second, the thermal capacity of the wall would dissapear and the temperatures in the room would be quite the same. And finally, the air would flow freely from one room to another.

My question is: Is this really happening just by making the holes in the walls? I am quite sure that the daylight is going from one room to another as expected, the temperatures of the air are also quite close in all rooms with these partition walls, but I am not quite sure about the airflow. Do I need to check the Macroflo box in Apache sym when doing the Dynamic simulation? or no matter what the air flow trough these rooms is ensured?

Thank you in advice,

Julian

[PCully]

Hi,

The lighting applications will take account of internal holes but you may have to make sure you select a high enough quality setting before calculating.

You should tick the MacroFlo link on the Apache simulation settings dialog before running the sim (before this you may want to review the opening types you have defined for the model and ensure they are assigned to the correct windows/doors), this way Apache and MacroFlo will calculate the bulk airflow through the building (this is what you require I believe). Vista will let you view the flow through any holes after the sim has completed.

Phil

[Julian]

Hi Phil,

I did not set any window or door openings in the model, only holes in the partition walls. That is why I thought maybe Macroflo was not required. As I mentioned before I found that temperatures are quite similar in the adjacent rooms (note that partion walls consist of a hole of 100% of their surface) which makes me think that the airflow is actually passing through the boundaries of the rooms with such partition walls. But is there any way I can make sure this is happening? How can I check the air flow trough the openings (holes)?

Mikel

[PCully]

Hi,

Here is a response from a while back (but still valid) that was sent by one of our consultants when asked a similar query, I think it answers your query and hopefully explains the behaviour you've seen so far. I'd go for the simulation with MacroFlo I think.

With no partition between the two spaces there can be no conduction exchange. With Macroflo turned off there can be no convection exchange.
Radiation however will be included in the calculation. If the radiant fraction of the heating system is low obviously there will not be a significant effect.
If convection gain between un-partitioned adjoining spaces is required in the calculation ensure Macroflo is turned on. Otherwise there will be no air movement.
All of the calculations used in the VE are explained in detail in the reference sections of the user manuals which accompany the installation.

Phil

[Julian]

Everything clear now! Thank you so much!!