[Radiance-general] modeling external glass lamella

[Greg Ward]

Hi Anne,

You need to share your trans specification, as this may be a  
problem.  It's too easy to get it wrong, and specify a surface that  
produces more light than it receives....

-Greg

> From: Anne Iversen <iversen.anne at gmail.com>
> Date: March 25, 2009 7:45:57 AM PDT
> 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