[Radiance-general] Re: Calculating maximum illuminance levels from daylight

[John Mardaljevic]

Ben,

There are various ways to estimate time-varying daylight
illuminance from a few 'static' simulations.  Your application
however seems to require fairly precise values.  I think the
only way to achieve them with any certainty is to carry
out a full blown time-varying daylight illuminance calculation
using a full year of 1hr met. data.  If you're not convinced,
see Figures 6.36 and 6.37 (Chapter 6) here:

http://www.iesd.dmu.ac.uk/~jm/zxcv-thesis/

for an illustration of the difference between static daylight
factors and time-varying daylight factors.

To generate time-varying daylight illuminances, try Christoph
Reinhart's DAYSIM package:

http://irc.nrc-cnrc.gc.ca/ie/light/daysim.html

-John Mardaljevic 

PS. I would have suggested also the DLS (IESD's own Radiance-based
tool to predict time-varying daylight illuminance).  But
it is currently broken becuase changes in Java have not yet been
incorporated into the tool. :(

-----------------------------------------------
Dr. John Mardaljevic                     
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
The Gateway
Leicester
LE1 9BH, UK
+44 (0) 116 257 7972   
+44 (0) 116 257 7981 (fax)
   
http://www.iesd.dmu.ac.uk/~jm