Far shading source

[Barbadori]

Hello,

I was wondering if there is any report/study about which horizon profile source is more accurate to be imported in PVsyst. I imagine that measuring the horizon on site is the best way to proceed but in the absence of on site measurements, what is the most recommended horizon profile source?

The easiest option would be to choose PVGIS horizon from web, that is embedded in PVsyst but I wonder how accurate this source is.

Many thanks in advance.

[dtarin]

Another option is meteonorm. The methodologies are similar. They use a digital elevation model and trace back out from the point of interest, calculating the height of the terrain for various azimuths. I think outside of on-site measurement, both are reliable. I have not seen a validation study, however.

[Barbadori]

Many thanks for the reply.

I've read that when using irradiance data measure onsite with pyranometers, the far shading effect is included in that data and it shouldn't be added with the horizon tool on PVsyst. Is that correct?

Cheers

[alihje]

I actually have the same question. Is it correct that horizon profiles should not be added when using meteo-files including horizon, i.e. measuerd data from a pyranometer?

[Michele Oliosi]

Yes, that would be the correct way to proceed. If the irradiance is already reduced by a horizon of some kind, no need to account for it a second time in PVsyst.

[dtarin]

One point to clarify, if the meteo data is taken directly from the pyranometer, then it is to be excluded. If the pyranometer data was used to adjust satellite data, then it is possibly excluded from the resulting adapted data (you will need to verify this), and thus you would include the horizon profile.