# HIgh illuminance values.

Hello Everyone,

I am performing simulations of Venetian blinds, for blind angles from 0 to 45.

The illuminance values for the blind angles of 0 degrees and 45 degrees seem to be fine.
However, I am getting very high illuminance values for the 15 degree and 30 degree blind angles for the sensor point which is closest to the window .
The values are ranging from 8000 lux to 20,000 lux. which I guess are totally unreasonable results when we have blinds placed in a room.

These values are higher for the blind angles of 15 degrees and 30 degrees than for the completely open blinds (zero blind angle gives us illuminance of 2500 lx).

Any idea why we are getting these high illuminance values for 15 and 30 degree blind angles?

Thank you.

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

Could there be direct sun slipping through?

Randolph

···

On Apr 22, 2009, at 6:42 PM, G V DEEPAK wrote:

Hello Everyone,

I am performing simulations of Venetian blinds, for blind angles from 0 to 45.

The illuminance values for the blind angles of 0 degrees and 45 degrees seem to be fine.
However, I am getting very high illuminance values for the 15 degree and 30 degree blind angles for the sensor point which is closest to the window .
The values are ranging from 8000 lux to 20,000 lux. which I guess are totally unreasonable results when we have blinds placed in a room.

These values are higher for the blind angles of 15 degrees and 30 degrees than for the completely open blinds (zero blind angle gives us illuminance of 2500 lx).

Any idea why we are getting these high illuminance values for 15 and 30 degree blind angles?

Thank you.

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

_______________________________________________
[email protected]

Is this for a single time of day/sun angle? My guess is that the steeper slat angles are letting some direct sun to strike your sensor points close to the window. Check the slat spacing, and the blind section overall.

- Rob Guglielmetti

···

On Apr 22, 2009, at 7:42 PM, G V DEEPAK wrote:

The illuminance values for the blind angles of 0 degrees and 45 degrees seem to be fine.
However, I am getting very high illuminance values for the 15 degree and 30 degree blind angles for the sensor point which is closest to the window .
The values are ranging from 8000 lux to 20,000 lux. which I guess are totally unreasonable results when we have blinds placed in a room.

These values are higher for the blind angles of 15 degrees and 30 degrees than for the completely open blinds (zero blind angle gives us illuminance of 2500 lx).

Any idea why we are getting these high illuminance values for 15 and 30 degree blind angles?

Thanks Mr Gulielmetti,

Yes its for single time and sun angle , we were trying sample simulations for 10, 11 am and 12 noon. I am getting these weird results. I have checked the geometry a number of times as well as all the parameters, these results seem very strange. any particular reason..?

Thank you

···

On Wed Apr 22 22:15:37 EDT 2009, Rob Guglielmetti <[email protected]> wrote:

On Apr 22, 2009, at 7:42 PM, G V DEEPAK wrote:

The illuminance values for the blind angles of 0 degrees and 45 degrees seem to be fine.
However, I am getting very high illuminance values for the 15 degree and 30 degree blind angles for the sensor point which is closest to the window .
The values are ranging from 8000 lux to 20,000 lux. which I guess are totally unreasonable results when we have blinds placed in a room.

These values are higher for the blind angles of 15 degrees and 30 degrees than for the completely open blinds (zero blind angle gives us illuminance of 2500 lx).

Any idea why we are getting these high illuminance values for 15 and 30 degree blind angles?

Is this for a single time of day/sun angle? My guess is that the steeper slat angles are letting some direct sun to strike your sensor points close to the window. Check the slat spacing, and the blind section overall.

- Rob Guglielmetti

_______________________________________________
[email protected]

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

I believe I've suggested this before, but did you try visualizing your space at these times? A fisheye view from the perspective of your sensor will usually tell you where the light is originating.

-Greg

···

From: G V DEEPAK <[email protected]>
Date: April 24, 2009 5:32:38 AM PDT

Thanks Mr Gulielmetti,

Yes its for single time and sun angle , we were trying sample simulations for 10, 11 am and 12 noon. I am getting these weird results. I have checked the geometry a number of times as well as all the parameters, these results seem very strange. any particular reason..?

Thank you

On Wed Apr 22 22:15:37 EDT 2009, Rob Guglielmetti > <[email protected]> wrote:

On Apr 22, 2009, at 7:42 PM, G V DEEPAK wrote:

The illuminance values for the blind angles of 0 degrees and 45 degrees seem to be fine.
However, I am getting very high illuminance values for the 15 degree and 30 degree blind angles for the sensor point which is closest to the window .
The values are ranging from 8000 lux to 20,000 lux. which I guess are totally unreasonable results when we have blinds placed in a room.
These values are higher for the blind angles of 15 degrees and 30 degrees than for the completely open blinds (zero blind angle gives us illuminance of 2500 lx).
Any idea why we are getting these high illuminance values for 15 and 30 degree blind angles?

Is this for a single time of day/sun angle? My guess is that the steeper slat angles are letting some direct sun to strike your sensor points close to the window. Check the slat spacing, and the blind section overall.
- Rob Guglielmetti