Sky type in DF recipe

grasshopper honeybee
1

Hi,

Which sky type is the DF recipe using in HB 1.0.0? I cannot find this information somewhere.
Thank you in advance.

2

Daylight Factor is always calculated with a uniform sky and it’s important to be aware of this since daylight factor cannot account from differences in daylight that result from changing building orientation.

This is just a fundamental limitation of the daylight factor metric.

3

Hallo dear @chris,

According to the European norm (and not only), the DF must be simulated under a overcast/cloudy sky.

Please confirm me, that the new version of the LBT calculates the DF with a uniform sky, because in that case I have to go back to simulating with the lecagy version.

Thanks and greetings

1 Like
4

Ah, you are right @LiamRuvio .

It’s an overcast sky in both Legacy and in the LBT plugin. And the overcast sky is ever so slightly different from the uniform sky in that it’s a little brighter on the top than on the sides:

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My point about DF not being sensitive to orientation (N, E, S, W) still holds but I guess this means DF accounts for skylights letting in more light per area than vertical windows.

5

You got me worried :smiley:

Thanks for the answer Chris.