Annual Daylight (DA) results too optimistic?

Hi everyone!
I was wondering if anyone had an opinion on the following. I am running Annual Daylight Autonomy simulations, testing a threshold of 160 Lux.
Windows have significant shading, including vertical fins and horizontal overhangs. VLT and reflectance values have been set with quite conservative values. Simulation is running ok however, I find the results are too optimistic in terms of achieving very high levels of daylight which I find a little suspicious.
I have reviewed the script a lot but I can’t find any issues with it. I am attaching some screenshots of the results, the model, and also the script (LB Tools Version 1.2). If anyone can take a look and share your thoughts on this I would really appreciate it!

Thanks all!
Mica

Annual Daylight_Test01.gh (282.7 KB)




Hi,
I suggest posting a simplified version of the problem (probably just one room (small). I’m sure the results will point to the same issue you want to check.
This version is too heavy for just testing.
-A.


Have you got this error?

Hi Abraham,
Yes that’s a good call, thanks!. I’ve simplified the model, to test only one room. While doing that, I compared the full model simulation vs the simplified one (Which are exactly the same) and I’ve noticed some differences in the results as well. The difference between results its still within a 10% margin so I guess its possible. The simplified version model results look like they are making more sense. However, I’m still unsure if these results are ok or too high.
Here is the simplified model and a comparison screenshot of the same space:
Annual Daylight_Test02.gh (127.3 KB)


Hi Naga,

No, I don’t get that error

That error is because @Naga has installed core libraries for LBT 1.3 but you have built your Grasshopper definition using LBT 1.2 components. Just run the LB Sync Grasshopper File and this will update all of the components on the canvas to be synced with your installation.

Your DA results don’t seem to optimistic to me if you’re using a threshold of 160 lux and you’ve run the simulation with plenty of ambient bounces.

Hi all,
I´ve just downloaded this example after updating the components and synchronizing them. I´ve also added the floor to the brep which feeds the GenPts because it was empty and changed the grid offset distance to -0.75 because it was -0.75 below ground. But the annual daylight simulation doesn´t work.
Could you please help me?
Thanks in advance,
Patricia

Annual Daylight_Test02_PC.gh (143.4 KB)

Hi Chris,

Thanks for the reply!
Yes, I agree that the 160 lux threshold is not too high. Regarding the ambient bounces, I’m currently running the simulation with ab 6. Does that number make sense or it is too high? What would be a recommended (or conservative) value for that?

RIght now i’m having trouble running AnnualDaylight recipe, so can’t check.
Indeed the 160 lux is not a very high threshold. But if you want to be more systematic you can run a series of (short) tests just to get a better feeling.
I would take a simple box with window on one facade with/without shades, 2-3 window sizes and changing the orientation (north). I believe this will improve your instincts.
6 bounces is plenty. 4-5 will be enough.
-A.