Hi,

We have a building with electrochromic glazing and need to calculate sDA and ASE for the LEED v4 daylight credit. I am familiar with the calculations of DA etc, including use of dynamic shading, but have never used the metric option for LEED v4. Is there any more documentation on this?

Some questions:

- specific radiance parameters to adjust, such as -ab to at least 4, I believe?

- In DIVA, the "blinds" for this metric are controlled according to IES LM-83-12, however, electrochromic glazing should be modelled per design specification. In this case, for the energy calculation, we have controlled the glazing based on the external solar radiation on the facade, it would be logical to use the same control for the daylight simulation in DIVA.

- is it possible to import tables with annual values for the activation of each shading group? We need at least four shading groups (one for each orientation).

- where do I define the material for these "blinds"? The glazing has four daylight transmission steps.

This is getting very complicated, is it even possible? I found a previous post regarding electrochromic glazing and LEED sDA and ASE, but it reffered to Grasshopper..

Thanks for your feedback!

Sarah

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Hi Sarah,

For a system that is not a manual control, you can simply run the building with detailed shading controls that mimic the ones in the final building for LM-83 calculations. There is some guide on this here. I also gave a presentation on it some years ago.

To directly address your questions...

- In DIVA, the "blinds" for this metric are controlled according to IES LM-83-12, however, electrochromic glazing should be modelled per design specification. In this case, for the energy calculation, we have controlled the glazing based on the external solar radiation on the facade, it would be logical to use the same control for the daylight simulation in DIVA.

The default advanced shading controls in DIVA will only allow you to control based on exterior illuminance (not irradiance). Would that work in your case?

- is it possible to import tables with annual values for the activation of each shading group? We need at least four shading groups (one for each orientation).

No. If you need that level of control, the best you can do is to simulate each part separately and stitch the illuminance files together.. a not very nice process.

- where do I define the material for these "blinds"? The glazing has four daylight transmission steps.

See here: http://diva4rhino.com/user-guide/rhino/custom-radiance-materials

 Best,

Alstan

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