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

[Seyedmostafa Mousavi]

Hi David,

Great! Thanks heaps.

Regards,
Mostafa

From: David BRADLEY <d.bradley at tess-inc.com>
Sent: Saturday, 12 June 2021 12:33 AM
To: TRNSYS users mailing list at OneBuilding.org <trnsys-users at lists.onebuilding.org>
Cc: Seyedmostafa Mousavi <sm.mousavi at unimelb.edu.au>
Subject: [EXT] Re: [TRNSYS-users] How to model a cavity zone under a building

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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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