[TRNSYS-users] What's the relation between the solar radiation W/m² and the illuminance

[David Bradley]

Yujun,
  The illuminance is a measure of luminous power as opposed to a measure 
of "pure" radiative power. A measure of pure radiative power weights all 
wavelengths of the radiation equally whereas measures of luminous power 
account for the fact that the eye is more sensitive to visible light 
wavelengths. There is certainly a relationship between the amount of 
solar radiation amount and the luminous radiation called the luminous 
efficacy. I have seen methods for calculating the luminous efficacy of 
certain window and skylight configurations but there is also a luminous 
efficacy associated with the atmosphere. If you run one of the TMY2 
sites from the US, and look at the output for illuminance and solar 
radiation, you can divide one by the other and see what the general 
magnitude of the luminous efficacy is.
Kind regards,
 David


Yujun TAO wrote:
> Hello,
> Can someone tell me the relation between the solar radiation W/m² and 
> the illumance? and the unit of the illumance in the type 15?
> Thanks
>
> Yujun TAO
>
> ------------------------------------------------------------------------
> Envoyé avec Yahoo! Mail 
> <http://us.rd.yahoo.com/mailuk/taglines/isp/control/*http://us.rd.yahoo.com/evt=52423/*http://fr.docs.yahoo..com/mail/overview/index.html>.
> Une boite mail plus intelligente.
> ------------------------------------------------------------------------
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at engr.wisc.edu
> https://www.cae.wisc.edu/mailman/listinfo/trnsys-users
>   

-- 
***********************************************************************
Thermal Energy System Specialists (TESS), LLC 
David BRADLEY                      2916 Marketplace Drive - Suite 104 
Partner                            Madison, WI 53719 
                                   USA
P: +1.608.274.2577 
F: +1.608.278.1475
E-mail: bradley at tess-inc.com 
Web Pages:  http://www.tess-inc.com    and      http://www.trnsys.com

***********************************************************************

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20080721/07fdc2b3/attachment-0005.htm>