[TRNSYS-users] mix air (convection) of two zones of not rectangular room

[Karol Bandurski]

David,

 

What you mean by: 'simply to define some arbitrary (usually high) mixing
rate between the two parts of the zone' ?

 

How to define this mixing rate, where should I do this? 

If I use VirtualSurface between two zones there are no possibility to make
'coupling air flow'. VirtualSurface is invisible in TRNBuild.

 

Kind regards,

Karol 

 

From: David BRADLEY [mailto:d.bradley at tess-inc.com] 
Sent: Friday, September 30, 2011 6:49 PM
To: Karol Bandurski
Cc: trnsys-users at cae.wisc.edu
Subject: Re: [TRNSYS-users] mix air (convection) of two zones of not
rectangular room

 

Karol,
  Unless you are concerned about the radiation exchange within the zone (and
have selected the detailed zone geometry model) you don't really need to
worry about having only concave zones. Having said that, there are a few
options for estimating the air exchange between air nodes. The simplest
method is simply to define some arbitrary (usually high) mixing rate between
the two parts of the zone. This will keep the two zones at approximately the
same temperature. The other alternative is to use either TRNFlow, COMIS, or
CONTAM/Type97 to predict the air exchange rate based on the temperature and
pressure differences between the two air nodes. These second alternatives
are a significant amount of work so I would first look at your building's
energy consumption assuming that there is no air exchange between the two
zones, then look at the energy consumption assuming significant air
exchange. If there isn't a big difference you know that the building isn't
very sensitive to the air exchange rate and you can save yourself the time
of modeling it by setting an arbitrary air exchange rate to achieve a
realistic level of comfort difference between the two zones.
kind regards,
 David
 

On 9/29/2011 04:08, Karol Bandurski wrote: 

Hi,

 

The problem is from Type 56.

 

I have house with few rooms which are not rectangular, they are concave. So,
I can't make one room=one zone.

 

I divided room on rectangles to make zones, and walls between zones of one
room are VirtualSurface. Radiation is seemed OK, but air between two zones
of one room isn't mixed.

 

What can I do? Is it possible to solve this problem in TRNBuild or I have to
go outside Type 56 and operate in Simulation Studio?

 

Regard,

Karol

 






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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA
 
P:+1.608.274.2577
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d.bradley at tess-inc.com
 
http://www.tess-inc.com
http://www.trnsys.com
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