[TRNSYS-users] correct modelling of brick facade

Jeff Thornton thornton at tess-inc.com
Mon Jul 30 14:40:45 PDT 2012


 
<I think there is a TYPE that you could buy from TESS. > 
Indeed we
do have a ventilated facade model - but it takes the ventilation flow
rate as an input so you'll have to do some work to figure out a
reasonable approximation. 
jeff

---

Jeff Thornton 

_President - TESS
LLC_ 

_22 N. Carroll Street, Madison WI USA 53703_ 

_Office: (608)
274-2577 Fax: (608) 278-1475_ 

_www.tess-inc.com_ 

_E-Mail:
thornton at tess-inc.com_ 

On 07/30/2012 4:25 pm, saleh saadi wrote: 

> I
haven't done that before. However, if I have this problem then, I will
solve it this way: 
> 
> Case-1: Non ventilated cavity: 
> 
> I will
assume that the cavity is an air layer with the properties of air. 
> 
>
Case-2: Ventilated Cavity: 
> 
> I will create an unconditioned thermal
zone for the cavity. I will search for some correlation to use for
ventilation rate inside the cavity. Another alternative to calculate the
mass flow rate would be to derive it analytically using Bernoulli
equation. I will then use equation block in TRNSYS to calculate the flow
rate and input the results in the cavity zone. 
> I don't know if this
approach is right for your application. 
> 
> regards, 
> Saleh ALSaadi

> 
> -------------------------
> FROM: leen peeters 
> TO:
TRNSYS-users at cae.wisc.edu 
> SENT: Tuesday, July 31, 2012 12:38 AM
>
SUBJECT: [TRNSYS-users] correct modelling of brick facade
> 
> Hi all,

> 
> when there is a typical construction of an outer wall with inside
to outside: 
> plaster 
> brick 
> insulation 
> cavity 
> facade brick

> 
> I wonder what the correct approach is... 
> I generally do not
model the outside layer as te cavity is ventilated and there is no way
to know what the ventiation rate will be in the cavity of my future
wall. 
> However, if I do it that way, I could not leave the emissivity
as it is for the insulation. That emissivity will react with the outside
climate. In reality, it will exchange thermal energy with the inside of
the facade brick, which gives a delayd effect and might be strongly
influenced by the water content of those bricks. 
> 
> Any suggestions?

> 
> Leen 
> 
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