Dear users,
I want to simulate a huge building (5500 m2) with a 20 cm concrete ground without isolation.
I don't really understand how the direct contact boundary condition works.
I made a ground wall composed of 20 cm of concret and 80 cm of calcar.
I realize that the simulation result (Tzone temperature) is very dependent of the ground temperature boundary condition.
I use type 77 with the depth of ground temperature of 1m, the amplitude of 12 and the mean temperature of 12.
If I change the parameters of type 77, the zone temperature results change a lots.
In the inf file, i get u value result of my floor : THERMAL CONDUCTANCE, U= 4.21086 kJ/h m2K; U-Wert= 0.97567 W/m2K
If I don't put the 80 cm of calcar, I get the following u value :
THERMAL CONDUCTANCE, U= 37.80000 kJ/h m2K; U-Wert= 3.77020 W/m2K
Is this normal ? What means U-Wert ?
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Dr. Loïc Tachon (+33) 6 7440-0536 (France)