[Radiance-general] Illuminance Values in Ecotect/Radiance

[Villian Wing-Lam LO]

Hello,

 

I am having some problems in calculating illuminance levels for my model. My
model was built and imported into Ecotect and then exported to Radiance for
lighting analysis. The Radiance-calculated value for luminance (cdm-2) are
similar to what I measured on-site. However, once I exported my model to
Radiance for illuminance calculations (lux),  the lux values were ten times
higher than what I measured from the site! Can anyone advise what might go
wrong with my simulation? The simulation was conducted for a night time
scenario and with artificial lighting only. Does Radiance take into account
the luminous efficacy of the lamps? I read other threads too and it seems
that the default luminous efficacy value is set to 179 and that is for
daylit condition. However, a general efficacy value for, say, incandescent
lamp is 14. I do not know where to set the luminous efficacy in
Ecotect/Radiance and I am not sure if this is the reason why the computed
lux values are approximately ten times higher than in the reality?

 

Many Thanks,

vil

 

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