# Antwort: simulation of an internal roller blind

Hi!

this is interesting info. i would like to know why the use of a factor of
1.088579? Sorry if I missed something already.

Best regards,

Pierre-Félix Breton

···

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pfbreton@pfbreton.com
www.pfbreton.com <http://www.pfbreton.com/>

-----Original Message-----
Lahme
Sent: Wednesday, February 15, 2006 1:00 PM
Subject: Antwort: [Radiance-general] simulation of an internal roller blind

Dear Caroline,

I'd recommend to combine the radiance materials glass and trans assigned to
two planes.

1. With the material glass you take into account the angular reduction of
transmission (which the trans material doesn't have). To achieve a
transmission of 2.5% you should use for the R, G and B value of (2.5% *
1.088579).

2. To give the roller blind a diffuse transmission you can add the material
trans to the second plane. Here you should use for the R, G and B value 1
(100% transmission). The diffuse part of transmission you can control via
the 7 th parameter (0 = all diffuse).

Hope this helps.

Kind regards

Andreas

ALware Andreas Lahme
Leopoldstr. 7a
D-38100 Braunschweig
GERMANY
Fon: +49 . 531 / 250 72 - 80
Fax: +49 . 531 / 250 72 - 81
Mail: a.lahme@alware.de
Internet: www.alware.de

-----Ursprüngliche Nachricht-----
Gesendet: 15.02.2006 18:39
Betreff: [Radiance-general] simulation of an internal roller blind

I would like to simulate in RADIANCE an internal roller blind, which has
according to the supplier (unfortunately they do not know more) the
following properties:

as optical properties(reference to T65):
transmission: 2,5 %
reflection (to the outside): 71,8 %

could anybody give me please a hint which is the best way to implement this
I could accept a simplification, but what kind of material is the best
choice to do so (glass, trans)?
Has anybody experiences with this?

I would appreciate any help,

sincerely yours,

Caroline

--
Telefonieren Sie schon oder sparen Sie noch?
NEU: GMX Phone_Flat http://www.gmx.net/de/go/telefonie

_______________________________________________

An alternative approach would be to use "transdata" or "transfunc" to model the roller blind using a single polygon. Of course, this would require one to measure or estimate the angle dependent direct hemispherical transmittance of the system. This information can be retrieved through integrating sphere measurements. Ad hoc, I do not see why a roller blinds system should exhibit the angular transmittance properties of a single glass pane. Maybe someone more qualified could comment on this?

If you are not sure how to use trans or transdata, we have done a Radiance validation study for this kind of work, comparing the trans and transdata models to measurements in a full scale mock-up. The results will be most likely be published in a special issue on 'Daylighting' in Energy and Buildings in June 2006. Anybody interested in a sneak preview of the paper, drop me a line.

Christoph

···

________________________________

Sent: Wednesday, February 15, 2006 1:00 PM
Subject: Antwort: [Radiance-general] simulation of an internal roller blind

Dear Caroline,

I'd recommend to combine the radiance materials glass and trans assigned to two planes.

1. With the material glass you take into account the angular reduction of transmission (which the trans material doesn't have). To achieve a transmission of 2.5% you should use for the R, G and B value of (2.5% * 1.088579).

2. To give the roller blind a diffuse transmission you can add the material trans to the second plane. Here you should use for the R, G and B value 1 (100% transmission). The diffuse part of transmission you can control via the 7 th parameter (0 = all diffuse).

Hope this helps.

Kind regards

Andreas

ALware Andreas Lahme
Leopoldstr. 7a
D-38100 Braunschweig
GERMANY
Fon: +49 . 531 / 250 72 - 80
Fax: +49 . 531 / 250 72 - 81
Mail: a.lahme@alware.de
Internet: www.alware.de

-----Ursprüngliche Nachricht-----
Gesendet: 15.02.2006 18:39
Betreff: [Radiance-general] simulation of an internal roller blind

I would like to simulate in RADIANCE an internal roller blind, which has
according to the supplier (unfortunately they do not know more) the
following properties:

as optical properties(reference to T65):
transmission: 2,5 %
reflection (to the outside): 71,8 %

could anybody give me please a hint which is the best way to implement this
I could accept a simplification, but what kind of material is the best
choice to do so (glass, trans)?
Has anybody experiences with this?

I would appreciate any help,

sincerely yours,

Caroline

--
Telefonieren Sie schon oder sparen Sie noch?
NEU: GMX Phone_Flat http://www.gmx.net/de/go/telefonie

_______________________________________________