[TRNSYS-users] thermal storage wall

Michaël Kummert kummert at engr.wisc.edu
Tue Dec 21 15:26:50 PST 2004

> I would like to give a trombe wall glazing a thermal mass in order to 
> model a kind ok ventiladed facade. As long as this type is made, the 
> glazing is massless and we loose part of the chimeny effect induced into 
> the air in the gap between the glazing and the wall. I suppose I have to 
> modify the type 36...how to do it? (note I am using TRNSYS 15).
> any suggestion in welcome.

Assuming I understand what you want to do correctly:
If you really want to model glazing with thermal mass I can only think 
about one solution, which I never tried and which is probably a little 
crazy (I hope other users will correct me if I am wrong somewhere):
You can model the ventilated façade in Type 56 with the normal window 
model, which will simulate the optical properties very accurately. You 
can then output the incoming radiation on each surface in the air gap 
and use those outputs as inputs in another zone (or another simulation) 
where you model glazing as a standard wall (i.e. using the actual glass 
thickness and thermal properties of the glazing) and use WAGAIN's to 
input incoming radiation on all surfaces.
I assume that you won't see any difference unless you use a short time 
step and are interested in the surface temperature of the glazing 
itself. You also have to keep in mind that the way Type 56 (even with 
TRNFLOW) simulates stack effect in a ventilated façade is approximative 
so I am not sure taking the thermal mass of the glazing into account is 
the first step to take if you want to increase the accuracy of your model.

I hope this helps,

Michaël Kummert


Michaël Kummert

Solar Energy Laboratory - University of Wisconsin-Madison
1303 Engr Res Bldg, 1500 Engineering Drive
Madison, WI 53706

Tel: +1 (608) 263-1589
Fax: +1 (608) 262-8464
E-mail: kummert at engr.wisc.edu

SEL Web Site: http://sel.me.wisc.edu
TRNSYS Web Site: http://sel.me.wisc.edu/trnsys

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