The improved LEED Daylight Option I recipe makes it easier to pass the hourly 2% rule

[mikkel]

Hello community!

We have made important improvements to the LEED Daylight Option I recipe to make it easier to pass the hourly 2% rule to receive any LEED points. The source of the improvement is a change to how the blinds are modeled in the recipe.

What’s new?

Two new inputs have been added to the recipe. These inputs define how the blinds are modeled.

• diffuse_transmission: Represents the fraction of light that is diffusely scattered as it passes through the blinds. The default value is 0.05 (5%).
• specular_transmission: Represents the fraction of light that passes through the blinds without scattering (i.e., specular transmission). The default value is 0 (0%).

How it works

The blind geometry is modeled by duplicating the aperture geometry and translating it to avoid overlapping surfaces. The blind material is modeled using the Radiance trans modifier based on the two new recipe inputs.

The blind geometry and material are automatically added as a second state for each aperture group. This change will add to the ray tracing time, but in return, it is now easier to pass the hourly 2% rule. The section on the 2% rule from the original release post is still relevant:

2% rule | Dynamic schedules

The 2% rule is used to compute the dynamic schedule. There is a check for each hour of the analysis period to see if 2% or more of the sensor points or floor area receive 1000 direct illuminance. If the total of all unshaded aperture groups in a room yields less than 2% for a given hour, the unshaded states will be used to calculate sDA. If the percentage is greater, it will check all combinations of shaded aperture groups and choose the combination that returns the highest percentage of less than 2%, i.e. the least shaded combination.

While the blinds are automatically added as a second state for each aperture group, you must still set up the base aperture groups in the model. Read this section if you are unsure about how to create the aperture groups. Pollination Rhino users can use the PO_GenApertureGroups command. If you use Ladybug Tools and Honeybee for creating your input model, you can use the HB Automatic Aperture Group component.

Notes

• The recipe inputs shade_transmittance and shade_transmittance_file will no longer be available.
• The changes are a result of this topic initiated by @charliebrooker.

You can find a sample run on Pollination here: LEED Daylight Option I Sample.

Let us know if you have any questions.

[adaversa]

Hi @mikkel,

This is very exciting news! Thank you and the team for your hard work and continuous improvements to the recipe.

I have been testing the new script out today and have come across the following error:

ValueError: State of __static_apertures__ must be any of [0] for on or -1 for off. Received state 1.

I am continuing to investigate if this happens due to a specific input parameter or geometry configuration, but any insight would be appreciated!

Thanks

[mikkel]

Hi @adaversa,

Thanks for reporting the issue!

This is likely because I missed something when copying the new post-processing from the old version. I was able to re-create the issue, and I have fix for it. Is it possible for you to share your model (in a PM if privacy is an issue). I just want to test it on your model before pushing the fix.

[adaversa]

@mikkel,

I’ve PM’d the file to you. Please let me know if you need anything else and I look forward to trying out the fix!

Thanks,