[TRNSYS-users] Problem in creating a new wall type

[dbartosz]

Dear Issa,
You foget that U-value normaly its U=1/R and on R influence convective and 
radiative heat transfer coefficent (inside and outside wall) and never 
U-value will be devided by 2 if you change thikness single layer frpm 0.1 to 
0.2 m.

Regards
Dorota
----- Original Message ----- 
From: "Issa Jaffal" <issa.jaffal at univ-lr.fr>
To: <trnsys-users at engr.wisc.edu>
Sent: Thursday, March 15, 2007 3:30 PM
Subject: [TRNSYS-users] Problem in creating a new wall type


> Dear All
> When i was trying to make a new wall type in the wall type manager; i
> couldnt explain how the Uvalue in the wall type manager is calculated,
> for istance:
>
> if i make a wall with a single layer of 0.1 m of Concrete  U-value =
> 4.595 and if i make a wall with a single layer of 0.2 m of Concrete
> (same layer type)  U-value=3.770 but normaly the U-value will be devided
> by 2 if i double the thikness form 0.1 to 0.2!!!
>
> I tried to change the values of convective heat transfert coefficient
> but  the Uvalue didnt change:
>
> So how we can explain theses values the U-value ?
>
> Regards
> Issa JAFFAL
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