How can I input direct and diffuse radiation for using Perez Sky Model

Hello,
I'm using the perez sky model (custom sky) to calculate the illuminance ( Grid-based ) in DIVA.
Now I have two questions;

1.How can I input Direct and Diffuse radiation in DIVA?

 When I chose "Custom Sky Model (Perez Sky Model) ”,   only "Global Horizontal irradiation" window appears.
we don't have the option to input direct radiation and diffuse radiation directly into DIVA?

2. What is the theoretical model to transform "Global Horizontal irradiation" to direct radiation and diffuse radiation ?
I  guess DIVA transforms global horizontal irradiation into direct and diffuse radiation.
In DIVA / temp folder, the text file (....._sky.rad_transformed.text) appear and I guess this file show the transformed results.
What is the theoretical model to transform them ? How is it transformed into direct and diffuse radiation ?

Thanks,

Yukari

Tags: Custom, Diffuse, Direct, Model, Perez, Radiation, Sky, radiation

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Hello Yukari,

I've been away from the forum for much too long, and I apologize that no one answered your question. Being that so much time has passed, this is likely no longer useful to you; however, I would still like to respond.

1. DIVA is automatically splitting the radiation into direct and diffuse, if you already have the separated data, the Rhino toolbar GUI won't be useful. You can do this in Grasshopper by choosing the Perez Direct + Diffuse input for the sky type and zooming in to display the Dir and Dif inputs.

2. The Reindl method is being used to split the direct and diffuse.

Best,

Alstan

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