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

To: Karol Bandurski <karol.bandurski@put.poznan.pl>

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

From: David BRADLEY <d.bradley@tess-inc.com>

Date: Fri, 30 Sep 2011 11:48:39 -0500

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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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