Boland irradiance decomposition

[Mark Mikofski]

Hi pvlib pythonistas,

Has anyone heard of the Boland decomposition algorithm? It's mentioned in this talk: https://www.osti.gov/servlets/purl/1569197

I've heard it's not as accurate as DIRINT, but it's only a few lines long. Similar to Erbs it only uses the clear sky index, kt (ghi / ghi_clearsky), and the GHI

DHI = GHI / ( 1 + exp(-5 + 8.6 * kt) )

Is there interest to add it? Does anyone have a reference for it? Does any tool we know of use it?

thanks,

Mark

[cwh...@sandia.gov]

That formula with the exact coefficients is in chapter 8 of this book: https://link.springer.com/chapter/10.1007/978-3-540-77455-6_8  I have an electronic copy but I can't share it.

Here's a paper with the same formula but slightly different coefficients: https://www.researchgate.net/publication/229873508_Modelling_the_diffuse_fraction_of_global_solar_radiation_on_a_horizontal_surface

I'm not aware of this model in use.

[Mark Mikofski]

Does anyone think that Boland is a useful addition to pvlib given the 2 references Cliff has provided? Seems like low hanging fruit, and evidently it's there out in the wild. I know of at least 2 uses of it. 

[cwh...@sandia.gov]

The "lib" in pvlib stands for library, so on principle I'm not opposed to adding it to pvlib.irradiance. Because I'm curious, where is it used?

Cliff

[Mark Mikofski]

One use was proprietary. Since I didn't recognize it, I Googled and came up with the links I posted above. OK, looks like easy pickings