[TRNSYS-users] How to model a cavity zone under a building

David BRADLEY d.bradley at tess-inc.com
Fri Jun 11 07:32:39 PDT 2021


Seyedmostafa,

  You're on the right track. At least your method is the same that I 
used when I was modeling a similar situation. In my case there was a 
thin vinyl skirt around the building so I used its thermal resistance 
for my massless walls. I think the way to assess the infiltration into 
the cavity is to couple the Type56 thermal model either with CONTAM 
(using Type97 or Type98) or with TRNFlow. Both are designed to estimate 
airflow between pressure nodes in buildings.

kind regards,

  David



On 06/11/2021 05:06, Seyedmostafa Mousavi via TRNSYS-users wrote:
>
> Hi all,
>
> Hope you are very well.
>
> I’m modelling a cabin in SketchUp using the TRNSYS3D plugin. In the 
> real cabin structure, several steel posts were used to elevate the 
> cabin and separate its floor from the ground. The air easily flows in 
> this cavity under the cabin, see *Fig. 1*. To model the cavity, I’ve 
> considered a bottom zone in which the walls were defined as /Massless 
> Layers/ with R-value of 0.044 h m^2 K/ kJ (equal to the air gap), see 
> *Fig. 2*.
>
> However, I’m not sure if this modelling process is correct. Do we have 
> any option in TRNSYS to consider such cavity under buildings?
>
> BTW, if this model is correct, how should I calculate the infiltration 
> rate for the cavity section? Any idea is highly appreciated.
>
> Thanks a lot for your help.
>
> **
>
> *Warmly,*
>
> *Seyedmostafa Mousavi*
>
> The University of Melbourne, Victoria 3010 Australia
>
> *E: *sm.mousavi at unimelb.edu.au <mailto:sm.mousavi at unimelb.edu.au>
>
>
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI  53703 USA

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

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

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