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

[Issa Jaffal]

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