[Radiance-general] Illuminance Values

[G V DEEPAK]

Hello Everyone,

I am simulating a simple office space 10' X 18' with a 6' X 6' 
window, and the automated Venetian blinds. I am trying to compare 
Illuminance values for two models:
1.        In the base case the slats have the same tilt angle at 
one point of time ("conventional control").
2.         In the prototype model, the blinds are divided into 
three sections: Top , Middle and Bottom Blinds, each of equal 
dimensions ("splitcontrol"). In each section blinds can have the 
different slat tilt angle.

For pilot testing I tested  conventional control for  0, 45 and 90 
degrees and split control for 0, 45, and 90 degrees, too (i.e. I 
kept the same tilt angle in each section of the split blinds just 
for the pilot testing  and the result  comparison purpose).

The results that I obtained show variation in the values of 
Illuminance obtained for these two models (results difference 
ranges from 10-150%) although the results should be the same.

Conventional Blind
genblinds whitealum main 0.0125 1.82 1.88 195 90 |xform -rz 90 -t 
2.71 0.05 0.8>conventional90.rad

Split Blinds

genblinds whitealum main 0.0125 1.82 0.63 66 90 |xform -rz 90 -t 
2.71 0.05 2.06>66-1-90.rad

genblinds whitealum main 0.0125 1.82 0.63 65 90 |xform -rz 90 -t 
2.71 0.05 1.43>66-2-90.rad

genblinds whitealum main 0.0125 1.82 0.63 65 90 |xform -rz 90 -t 
2.71 0.05 0.8>66-3-90.rad



I am using the following script to obtain the results.

#!/bin/csh -f

set mon=01
set month=Illuminancesplit90
set day=01
set coord=(-a 30.00 -o 82.35 -m 84)
rm $month.out
while($day<32)
foreach hr(08 09 10 11 12 13 14 15 16 17)
echo "hr=$hr"
set skypar=($mon $day $hr +i $coord)
echo "$month/$day/$hr">>$month.out
oconv -i 66-1-2-3-90.oct '\!gensky '"$skypar" sky.rad>hr.oct
rtrace -h -I -ab 1 -ad 4096 -as 128 -av .02 .02 .02 
hr.oct<mainsamples.inp|rcalc -e 
'$1=47.4*$1+120*$2+11.6*$3'>>$month.out
#`./newglares.csh hr.oct $month.out`
echo " ">>$month.out
rm hr.oct
end
@ day++
echo "day=$day"
end

Considering the fact that we use the same room model, same window 
settings and blinds, why is there such variation in the values of 
results obtained?

Thanx.


G V DEEPAK
Graduate Research Assistant
M.E. Rinker, Sr. School of Building Construction.
University Of Florida.