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

[jeannieboef <jeannieboef@gmail.com>]

Firstly, check that you want to model with the water diffussion  
through constructions (I don't know if this is standard for the  
approach normally used in simulation)...usually this is only used with  
Finite Diference type solving algorithms. You may be able to change  
between algorithms. Secondly, you could think of how to "switch off"  
the sun and wind effects in the insulation if that is your outer layer.

The ventilation behind the facade brick is not mechanical, and lacking  
wind, will be almost 100% stack driven. This is hard to approach.  
There may be ventilated facade options (types or inbuild in type 56)  
as there is in EnergyPlus. See if you can find them for the best  
results.

Sent from my iPhone

On 30.07.2012, at 22:38, leen peeters <l.f.r.peeters@gmail.com> wrote:

> 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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