Hourly luminance on a desk

grasshopper honeybee
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1

Hi all,
I’m working on a project where I’m trying to assess some daylight comfort, using the luminance on the desk. In the model i have a space resembling an office, some desks, and points and vectors that represent the point of view of the occupants. I wanted to obtain the annual hourly values of luminance on the desk, similarly to what is usually done for illuminance on the desk, but i couldn’t find an easy and fast way.
Any suggestion?

Unfortunately being a new user i can’t attach the file so here’s a link to the gh file

Thank you!

2

Hi @momoelshemy, there is a component for loading the hourly results from an annual study.

Have you tried that?

3

Hi @mostapha, maybe I didn’t explain properly my problem. My issue is whether it is possible to calculate annual luminance on a surface (like the annual daylight analysis done for illuminance) or not. The only way I found to assess the luminance is by performing a point in time analysis, which is done for one single hour. My goal is to perform an annual analysis, obtaining 8760 values of luminance on the surface (in this case a desk). Giving a surface and the point of view (of an occupant in front of the surface), do you think it’s possible to calculate the annual luminance?
I hope that clarifies my problem,
Thank you

4

The component mostapha pointed to does what you are asking, @momoelshemy .

Here is a sample file that uses that component to plot hourly annual illuminance at one sensor point of an annual study.

5

Hi @chris, thank you for your reply. What I’m asking is how to simulate annual luminance, not illuminance. From what I see, through the honeybee-radiance components I can only simulate annual daylight (illuminance), annual glare and annual irradiance. Is there also a way to simulate annual luminance?
Then surely once I have the annual simulation I can use the “annual results to data” component to get the 8760 hourly values

6

Hi @momoelshemy ,

I think the place where we may be misunderstanding one another is that “luminance on a surface” (eg. a desk) is illuminance. You can evaluate luminance in a single direction but not for an entire surface. If you’re evaluating luminance over the whole hemisphere surrounding a surface, then you’ve effectively integrated the luminance over the solid angle and this gives you illuminance.

So, if you rephrased what you’re looking for as “luminance looking upwards” or “luminance looking downwards”, this might make more sense because “luminance on a desk” is not a valid concept.

Assuming that this rephrased luminance metric is actually what you want, you’re basically evaluating luminance for a single pixel pointing upwards (or downwards?). This would be similar to what the HB Point-In-Time Grid-based recipe gives you when you select luminance as the metric. If you run this point-in-time recipe using this metric, understand what the results are showing you and confirm this is what you want, I can show you the line of code that you can tweak in the Annual Irradiance recipe with the visible_ option set to True, which will basically give you this “luminance looking up.”

But I would also be curious about what the use case of this is since I have to imagine it does not involve human eyes, where light can enter from all directions over the hemisphere around them.