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Re: [TRNSYS-users] correct modelling of brick facade

<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@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@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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