marie de klijn's profile - activity

Hi,

I am using EnergyPlus 8.5 to simulate the effect of a ventilated slab in a simple zone. I want to make a comparison of my base case (without ventilated slab) compared to the same building with a ventilated slab. I managed to simulate and control the ventilated slab but I don't understand why when my ventilated slab is NOT operating the surface and air zone temperatures have a 0.1 degree difference from the base case.

I made sure the same material properties are used in both case. I even set the base case construction as two thin layer of concrete instead of a single thick one to mimic the set up of the ventilated slab in the tab "Construction : Internal Source". I tried to model my ventilated slab with no air flow, even no cavity at all but noticed no difference in my results. I also tried to remove the ventilated slab system all together with again no change in my results. The only remaining difference between my two cases is now that one as an internal source construction (which is not linked to any system) and the other has a regular construction. I am hoping that someone can explain to me why this temperature difference exist between my two cases. Thanks in advance.