[TRNSYS-users] Slab on grade - type 703d

[Bastien GARBAY]

Dear TRNSYS users,
 
I am using the Type 703d modeling heat transfert from a slab to the soil with interfaces with Type 56. I want to evaluate the influence of the insulation of the slab. I'm using the surface mode 1 in order to calculate the temperature of the slab back side surface. I read in the documentation that Type703 does not require that the user specify the thermal propoerties of the slab as these are taken into acount by the building model. However, when I change the Slab U-value in the Type703d I get very differents results in function of the U-value (for 1 until 36kJ/h.m².K) even if the thickness of the insulation in the building model does not change. Why?
Which U-value do I have to choose in the type 703d,  if I want to evaluate the influence of the slab insulation thickness?
 
Thanks for your answer.

Bastien
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