[BLDG-SIM] thermal modeling of air cavity

[Josh K]

Hi all;

I'm attempting to model a building that's facade has a ventilated 25mm air
gap between a 100mm brick veneer on the outer side and an EPS/steel stud
construction on the inside. I'm curious exactly how I should account for the
conductance/resistance of the air gap. This will obviously depend on the
inner and outer surface temperatures and the natural convection currents
that results from them, and further to that the outdoor wind speed; I'm
wondering if anyone is aware of any methods that have been developed to
approximate the equivalent thermal properties of an air gap in such a
situation.

The software that I'm using (EnergyPlus) allows one to specify an "air"
material object (Material:Air) to be used analogously with conventional
material objects (ie gypsum, EPS, etc) in forming wall constructions. The
only physical property that one can specify for the Material:Air object is
its thermal resistance in m²·K/W. Ultimately, what I'm trying to figure out
is the best way to specify this field.

My thanks in advance for any assistance that may be offered to me on this
matter...

Josh


Josh Kjenner, EIT, LEED AP
Manasc Isaac Architects Ltd.
10225 100 Avenue :: Edmonton, AB T5J 0A1
780.429.3977


===========================
You received this e-mail because you are subscribed 
to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe 
from this mailing list send a blank message to 
BLDG-SIM-UNSUBSCRIBE at GARD.COM
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20071002/37fc5932/attachment.htm>