Fritted Glass

[Algis Lencus]

My understanding is that without specialized spectral files, WINDOW offers only White Frit (#17 in the Shading library), which is based on the white diffuse and specular glass entries as the frit type.  Are there others? 

Is there a way to model a generic frit as part of a laminate without obtaining new spectral data? 

Is there a way to limit the influence of a frit to just the border of glass?

Thanks,

Algis

[Algis Lencus]

I should also note that use of the white frit (shading library entry #17) in THERM generates the following error when compiling an overall window system U and SHGC value in WINDOW 7.7.7:

"Calculation Warning: Calculation is complete and while results are probably correct, some parameters are outside the range of the equations prescribed by ISO 15099, which is the basis for this computer program. Tarcog failed to achieve solution tolerance (1e-5)."

[Jacob C. Jonsson]

Hi Algis,

WINDOW 7.8 will have a new way to provide spectral data with
direct-direct and direct-diffuse component split.

The data model for the frit examples in the shading library is
not going to be used any more.

On 11/23/2020 12:12 PM, Algis Lencus wrote:
> I should also note that use of the white frit (shading library entry
> #17) in THERM generates the following error when compiling an overall
> window system U and SHGC value in WINDOW 7.7.7:
> "Calculation Warning: Calculation is complete and while results are
> probably correct, some parameters are outside the range of the equations
> prescribed by ISO 15099, which is the basis for this computer program.
> Tarcog failed to achieve solution tolerance (1e-5)."

Are you running the shade layer by itself? That was not allowed
for a long time and could be the problem (in 7.8 it will be
allowed).

> My understanding is that without specialized spectral files, WINDOW
> offers only White Frit (#17 in the Shading library), which is based
> on the white diffuse and specular glass entries as the frit type.
> Are there others?

Not right now.
NFRC has approved methodology for measurement of diffuse glazing
and we expect CGDB will be populated with those products.
Timing of this is not trivial (we are validating the procedure
through an inter-laboratory comparison).

> Is there a way to model a generic frit as part of a laminate without
> obtaining new spectral data?

Not yet. That is further down the line than 7.8 but combination
of layers with scattering properties is on our horizon.

> Is there a way to limit the influence of a frit to just the border
> of glass?

In WINDOW use the same properties for every point of the glass,
so only the average properties of a layer is taken into
account and not the distribution of the different components
(i.e. fritted and unfritted).

So WINDOW would treat all windows where 20% of the area is
covered by frits the same way, regardless of pattern.
The way to make such a file is to take the weighted average
of the products in use.
E.g. For 20% Frit and %Clear
Tmix = 0.2*Tfrit + 0.8*Tclear
... etc for the other properties.

This is currently not built into the WINDOW UI so you have to
create the mixed file yourself and import into WINDOW.

Best,
Jacob

[Thomas Feurer]

Hi Jacob,

I wanted to bring this up again as i could not find any documentation of the new way this is handled in WINDOW 8.

Could you, or someone else, give me a short rundown how we should generate a new Frit in the current version of WINDOW?

Best Regards,

Thomas