Hi all,

I´m working on a project with an ETFE envelope, both for the facades and roof. These are made of 4-layered cushions with air gaps between them. To model the cushions in E+ I´ve used the detailed specs from the manufacturer as WindowMaterial:Glazing WindowMaterial:Gas objects.

E+ outputs show a resulting U-Value of 1.28 W/m2K which according to the local technical standards needs to be increased by 0.5 W/m2K to account for the curved nature of the cushion (and varying air gap thickness). Essentially a "safety factor".

Is there a way of doing so?

I´m aware of the WindowMaterial:SimpleGlazingSystem object, but that would change the thermal interaction between the ETFE layers, and affect the resulting internal cushion temperature - which is key for the comfort on the last floor, right below the roof.

It seems quite tricky to account for this safety factor while maintaining the precision that WindowMaterial:Glazing brings in this particular case. Has someone faced something similar?

Thanks in advance, Rafael