[Radiance-general] modeling external glass lamella

[Anne Iversen]

Dear Radiance list,

I have build up a model of a room with external glass blinds. The aim with
my simulations is to obtain the light transmittance of the glass blinds, and
for the entire system (blinds + window).

The blinds are modeled as polygons with the trans material. This means that
the blinds have no thickness in the model, but the reflectance and
transmittance values correspond to the information from the glass
manufacturer (r=0.31 and LT=0.65).

My approach is to obtain illuminance at three different locations:

1) Before the blinds, externally;

2) Between the blinds and the window, externally;

3) After the window, internally.



I have therefore made a grid of points in these locations. The orientation
of my measuring points is outwards, perpendicular to the façade.

My results show that the illuminance level is increased at loaction 2
compared to location 1, which is a result I do not find reliable! I have
placed calculation points in the entire height of the window with a spacing
of 0.01, to be sure not to have the result affected by high illuminance
levels locally. I would have expected higher illuminance levels locally due
to the redirecting of light in the glass blinds, but I would not have
expected a higher average illuminance level.  My simulation approach is
given below  – please let me know if you can find any mistakes.

Thanks in advance

/Anne





# /az 30,

#Room.rad includes room geometry,

#LamelSystem.rad includes geometry of the blinds,

#Syst2.rad includes geometry of the window system for mkillum


oconv materials.mat CIE.sky Room.rad LamelSystem30.rad Syst2.rad >
./profil30az0alt30/scene_window_prof30alt30az0.oct

cat Syst2.rad | mkillum -ab 4
./profil30az0alt30/scene_window_prof30alt30az0.oct
>./profil30az0alt30/scene_window_prof30alt30az0_i.rad

oconv materials.mat Room.rad
./profil30az0alt30/scene_window_prof30alt30az0_i.rad CIE.sky >
./profil30az0alt30/window_ii.oct



#points in grid inside the room
cat points.xyz | rtrace -w -h -I+ -ab 3 -aa 0.1 -ad 1026 -as 256 -ar 512 -ds
.3 -oov ./profil30az0alt30/window_2ii.oct | rcalc -e
'$1=179*($4*0.265+$5*0.670+$6*0.065)' >
./profil30az0alt30/prof30al30az0_2.dat

#points before and after the blind
cat extpoints.xyz | rtrace -w -h -I+ -ab 3 -aa 0.1 -ad 1026 -as 256 -ar 512
-ds .3 -oov ./profil30az0alt30/window_2ii.oct | rcalc -e
'$1=179*($4*0.265+$5*0.670+$6*0.065)' >
./profil30az0alt30/prof30al30az0_2ext.dat
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