[TRNSYS-users] suspended ceilings

[David BRADLEY]

Jörg,
  If there is a large plenum space above the suspended ceiling and 
particularly if the plenum extends over more than one thermal zone, the 
approach that I have often used is to define the plenum as a separate 
thermal zone and model the suspended ceiling as a "resistance only" 
layer separating the actual zone from the plenum zone. I think that if 
you add an air layer as part of your wall, you are assuming that the air 
is stagnant; stagnant air is a very good thermal insulator. If the space 
between the suspended ceiling and the concrete is thick (even only as 
thick as 30cm or so) then the air in it is not going to be stagnant at 
all and so therefore won't be as good an insulator as it is getting 
credit for being.
Kind regards,
  David


On 8/16/2011 04:22, Jörg Braasch wrote:
> Hello,
> I want to simulate a building with suspended ceilings. To do this I 
> will ad the layer of the suspended ceiling and a layer of air to the 
> concrete ceiling. I also substract the volume between the ceiling from 
> the volume of the room.
>
> Does anyone have experience in simulating with suspended ceilings? I 
> am not sure if I can do it this way.
>
> Thanks
>
> Regards
> Joerg

-- 
***************************
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