Definitions

[gonecrawfishin]

Hi,

Does anyone know the exact definition of the following:

- Pitch (spacing plus height of the modules, or projection of such to the ground base on tilt?)

- Coll. band width (height of the modules or projection to the ground based on tilt?)

- Top/bottom inactive band

- Ground area occupatino ratio, or A(coll) and A(ground). It seems this is not equivalent to "ground cover ratio", an NREL term, correct? GCR is a comparison of horizontal projections, whereas GAOR seems to compare lengths at different angles?

Anyway, a graphic in the help section would be useful. I'm trying to guess based on the little graphic but it's hard to really tell.

-Jen

[dtarin]

Pitch: Post to post distance

Coll. band width: width of the modules regardless of angle, i.e. if two in portrait, coll. band width is length of module * 2 + spacing between modules

Inactive band: distance the underlying structure extends past the module area. Often times this is zero.

GAOR: collector width/pitch

[AHSAN ALI]

Is no of sheds affected the performance, what means by no of sheds, plz elaborate

[Linda Thoren]

Yes the number of sheds will have an impact of the performance, considering that the first and the last rows are not accounted for in the same way, since they will not experience the same shading patterns as the tables in the middle of the system. When there are many rows, this difference may be neglected. You can read more about the impact in the following help page:
https://www.pvsyst.com/help/project-design/bifacial-systems/bifacial-systems-nbofsheds.html?h=number

 

[AHSAN ALI]

Can we simulate in unlimited sheds orientation, elevated structures or ground mounted only, but if ground mounted only then can we simulate L2,L3 structure in this, because in orientation we can only give pitch, collect band width (What is this?). No of Sheds also, but If I've a wide roof can I only install a single panel in unlimited rows I can select panels in front row more than one and also behind the rows then how to calculate or simulate, shading angle, collec band width etc.I can't understand bcz I want to install a 10kW system of 645W panel, but I give 16 no of sheds bcz of unlimited sheds, how can I reduce the qty of sheds bcz I want to install 8 panels in 1st row and 8 in 2nd and that's all, but how will manage

 

[Michele Oliosi]

@AHSAN ALI An important point here is understanding what "shed" means.

A "shed" in PVsyst is one row of PV tables in a row arrangement. A "shed" is not the same as a module:

• Because one table may have several PV modules.
• Because one row of tables has several tables in it.

In the diagram of the "Orientation" window, you can see three (generally) such rows depicted in blue. This is a cross-section or side view of the row arrangement.

This also means that the size of the tables is what you will enter in the parameters "coll. band width" and "top/bottom inactive bands". What matters is the vertical size, in other words the "height" or "width" depending on your perspective, but usually the short side of a table. 

The "Orientation" window is not where you will define the total number of modules. Here only the geometry matters. The "System" window is where you will define the number of modules properly.

In your example with 8 + 8 modules, you should define "Nb. of sheds" as 2.

[AHSAN ALI]

Okay, good, but when panel install in portrait then collect band width is the length of panel and when panel install in landscape then collect band width is the width of panel.
Is I'm correct? These Panels are installed in Portrait orientation and you suggest others if landscape orientation, and also tell that If I want to simulate this structure in unlimited sheds and pvsyst, because 2 panels gaps for albedo and air circulation , and there is no option in pvsyst that we select 23 panels, whatsever 1st guide about the collbandwidth of portrait and landscape, according to my suggestion when portrait then we take panel length and when landscape then we take panel width as collect band width, plz guide

[Michele Oliosi]

You are correct about width / length, although a shed may be several modules tall... this means that the collector band width could be 2, 3 or more times the size of a module.

About your system: the best way to model this in PVsyst is not via the "unlimited sheds" orientation. The unlimited sheds is useful when you have multiple rows of tables. Instead, your system is basically one table (with a gap). As far as the front side irradiance goes, the best is to do a 3D drawing and use the module layout shading calculation mode.

Unfortunately PVsyst does not model the backside irradiance in 3D, which means that in your case the backside irradiance model (bifacial model) would be quite wrong. Indeed, there are multiple 3D specificities in your system: the raised part of the roof, the gap in the modules, the different albedo, and the mounting structure. All of these cannot be modeled in PVsyst.

You could use the unlimited sheds as an approximation. In this case, please set the number of rows to 1, and the collector band width to 5 times the length of a module (+ gaps). The hole in the middle and differences in roof height cannot be modeled. Then you can use the bifacial model, but note that the results will be approximative.

[AHSAN ALI]

Thankyou So much for your guideline, one more thing to confirm that in unlimited shes orientation we can put the bifacial module height above ground but not the monofacial, so, how I can compare both mono and bifacial panels in parallel condition because in Actual I'm comparing the results of both mono and bifacial at same height, same orientation, same tilt angle, same height above ground but how? One thing and tell me the collect band width of panel if (2382mmx1134mm) have dimensions. and if in portrait direction and for this scenario explain how can simulate in Pvsyst, also plz guide about the DC grid system bcz for two panels or one there is no inverter available an also we experiment through MPPT meter readings. Right side Monofacial, left side bifacial placed at parallel condition

[Michele Oliosi]

On 12/9/2025 at 5:12 PM, AHSAN ALI said:

we can put the bifacial module height above ground but not the monofacial

Indeed, to model the front side irradiance (useful for monofacial) the height above ground is not used. There is therefore no problem in your comparison, even if you cannot enter the height above ground.

One table = one module in your example. Therefore collector band width = 2382mm when in portrait and 1134mm when in landscape.

If you check among all inverter manufacturers, there should be at least a few microinverters. However you can also define a new microinverter on your own, by modifying an existing one. You can therefore make a very low power one.

[AHSAN ALI]

So for comparison, both place at ground from fornt

 

[AHSAN ALI]

On 12/14/2025 at 2:58 PM, AHSAN ALI said:

One more question is that in Unlimited sheds only iso shading graph modeled, because pvsyst take calculate row to row shading, but if a building or tree close to the plant then that's shading how we can calculate in it,
and if we experiment on a single panel by shade one cell, horizontally, vertically then how can we analyze,
and if we want to experiment on one panel then how can we run simulation in pvsyst,
 if I use DC grid system then bifacial panel does not add, then tell me how I can calculate please guide,

 

[AHSAN ALI]

one thing more to clear that in real in my house a 13.340KW system installed with 15KW inverter, and also 23 Panels installed of 580W capacity/panel install, then why I can't modeled in PVsyst exact 23 panels but in reality I installed, in real I install a 15kw inverter but in pvsyst i use 10kw but pvsyst telling that inverter is oversized so what is this plz clarify thanks

[Linda Thoren]

hello,

In the print screen you have activated the "multi MPPT feature" and defined 3 MPPTs, though your inverter has 2MPPTs per inverter, this 1.5 inverters with a total of 15kWAC for a nominal PV Power of 13.9kWp. The following youtube tutorial shows in detail how to define your system configuration (in version 7):

 

[Linda Thoren]

On 12/27/2025 at 6:41 PM, AHSAN ALI said:

 

Indeed, the unlimited sheds only consider the row to row shadings. For a more detailed analysis of the shadings from objects such as trees and buildings, you can define a 3D scene and simulate the electrical shadings with the module layout. The following youtube tutorial illustrates haw to create a 3D scene, and the following link to our help page, describe how to define the module layout:

https://www.pvsyst.com/help/project-design/shadings/electrical-shadings-module-layout/index.html