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

David BRADLEY d.bradley at tess-inc.com
Fri Sep 30 09:48:39 PDT 2011


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
>
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at cae.wisc.edu
> https://mailman.cae.wisc.edu/listinfo/trnsys-users

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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