Question-and-Answer Resource for the Building Energy Modeling Community
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Hi Rafid, Great question, and thanks for the details! You have hit on one of the big limitations of the current implementation of Radiance in OpenStudio: multiple spaces' illuminance maps are not supported in a single thermal zone. This is obviously lame, and we are planning to fix this in a future release.
All is not lost, however; you can still use the basic Radiance tools in OpenStudio to look at the daylight distribution across the building and determine some general lighting savings potential. You could for example have one space's illuminance map span multiple spaces, and view the spatial daylight distribution. How different is the electric lighting across the spaces? I ask because you could also scale one space's lighting loads to cover a whole thermal zone, model the daylighting in one space, and get some general information about what the daylighting might do that way.
