Converting output from gencumulativesky to kWh/m²

asked 2015-08-26 09:06:46 -0600

dgleeson

78 ●4

updated 2015-11-09 14:14:43 -0600

__AmirRoth__

4446 ●5 ●17 http://bleedinggreenna...

Hi,

I've been experimenting with gencumulativesky and the -S1/-S2 switches to chose between the "smeared" representation of the sun and the "binned" representation of the sun. The version of gencumulativesky I have has a -r switch which the help text tells me divides the output by 179000 to convert from (I think) W/sr.m² to kWh/m².

The issue I have is that this does not appear to be applied to the SunFile.rad file which is generated as a result of chosing the binned option. Thus when I generate an image using the sky and sun output from gencumulativesky I get really big numbers (W/sr.m²).

I've experimented with feeding my image into pcomb and setting the -s factor to be 1/179000 (5.587e-6) and this appears to convert my numbers into the right ball park for kWh/m².

However I'm not entirely sure that what I've done is actually numerically correct. Does anyone have any guidance on the correct way to work with gencumulativesky with the binned suns and produce output in kWh/m²?

answered 2015-08-28 04:48:23 -0600

Mostapha Roudsari

1074 ●5 ●12 https://github.com/mos...

updated 2015-08-28 10:24:45 -0600

Hi @dgleeson. I think you need to email Christoph Reinhart or Darren Robinson directly about this. I'm not sure if they will ever check unmethours. You may have a better chance to get a reply if you send this question to radiance mailing-list (I know we decided to give unmethours a try but here are the cases that mailing list will probably work better for you.)

Not the answer to your question but you may find Radiance's gandaymtx as a very useful alternate to gencumulativesky.