Hi Valeria,
This is probably one for the FAQ (if only there was a FAQ)... Radiance has a preferred color space, but it does not require that you use it. You can assign the three (RGB) channels to be anything you like, including total solar transmission/reflectance/whatever. Bear in mind that solar heat gain is also affected by thermal conductance and convection, which are not considered in an optical ray-tracing calculation such as Radiance. To the extent that IR behaves as visible light, however, Radiance may be trusted.
I hope this helps.
-Greg
···
From: "Valeria De Giuli" <[email protected]>
Date: March 17, 2008 7:57:20 AM PDT
Hi all!
Sorry for my bad English. I'm a quite new user of Radiance and I'm
interested in energy performance of buildings. I would like to know if
it is possible to calculate the performance of a shading system
(venetian blinds, light shelf, etc.) in terms of reducing solar
radiation. Does Radiance consider all the spectrum in calculating
irradiance? My aim is to try different shading systems in a office
room and to analyse their bahaviour in terms of shading coefficient.
Any help would be appreciated. Thanks in advance,
Valeria
Hi Greg,
thank you for your reply! How can I change the contents of the channels?
Thank you in advance,
Valeria
···
2008/3/18, Greg Ward <[email protected]>:
Hi Valeria,
This is probably one for the FAQ (if only there was a FAQ)...
Radiance has a preferred color space, but it does not require that
you use it. You can assign the three (RGB) channels to be anything
you like, including total solar transmission/reflectance/whatever.
Bear in mind that solar heat gain is also affected by thermal
conductance and convection, which are not considered in an optical
ray-tracing calculation such as Radiance. To the extent that IR
behaves as visible light, however, Radiance may be trusted.
I hope this helps.
-Greg
> From: "Valeria De Giuli" <[email protected]>
> Date: March 17, 2008 7:57:20 AM PDT
>
> Hi all!
> Sorry for my bad English. I'm a quite new user of Radiance and I'm
> interested in energy performance of buildings. I would like to know if
> it is possible to calculate the performance of a shading system
> (venetian blinds, light shelf, etc.) in terms of reducing solar
> radiation. Does Radiance consider all the spectrum in calculating
> irradiance? My aim is to try different shading systems in a office
> room and to analyse their bahaviour in terms of shading coefficient.
> Any help would be appreciated. Thanks in advance,
> Valeria
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Thank you Lars for your reply! It's not easy to find the properties of
the materials in all the spectrum... Anyway, now I know what to do in
case.
Best regards and thanks a lot,
Valeria
···
2008/3/18, Lars O. Grobe <[email protected]>:
> thank you for your reply! How can I change the contents of the channels?
You do not have to "change" them, you must enter the values for any
simulation anyway. Define three channels you need, and enter them just
as you would do with red green and blue values in their corresponding
fields when defining reflection, transmission and emission of your
surfaces. Of course you must know the properties of you sources and
surface materials for these channels. The point is that in your mind,
you have to replace the meaning of the RGB-values, usually taken as
RedGreenBlue, with Channel1Channel2Channel3. Colors are just "channels"
of radiance in this meaning, so just change the wavelength and you can
use it for anything 
Of course as Greg already wrote you should consider if the effects of
radiance that are modeled in Radiance are enough or if you need other
energy transports for your work, too.
CU Lars.
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