How do you design a multiple inverter system withtwo orientations

[Paul.Rodden]

I am designing a roof mounted 300kW system with multiple roof surfaces and using multiple inverters (SMA STP's). Each roof element is essentially a gable design and all of the modules will be in one of the two orientations (exactly 180 degrees oppposite). Do I have to model it as two separate fixed tilt systems and then just add the result manually or can I use PVsyst to create a combined design. I tried the hetrogenous dual orientation option but couldnt get it to work. Your assistance would be welcome.

[André Mermoud]

The Heterogeneous option can be used for treating your case.

However with this option, the shading factor is computed only once, and applied on both orientations identically.

This may produce errors on the shading losses if the plan angles are too different (as for both opposite roofs). This is the reason why PVsyst puts a limit to the angle difference, and prevents calculation if it is overcome.

This limit may be changed:

- in the version 5, in the Hidden parameters: "Detailed Simulation Verification Conditions" / "Shadings with heterogeneous fields: max. angle difference".

- in the version 6, in the project's definitionm button "Albedo-Settings".

You can always perform 2 different simulations (one for each orientation) for analysing the effective error due to this approximate simulation.

[Cloud 9]

Ideally i would like to put in the 6 roofs with each orientation (and subsequent shading from other roof projections) with the different angles of the roof slopes and get a single calculation out

for a microinverter system where in shade only affects each panel and not strings etc

[Cloud 9]

The Heterogeneous is for 2 roof aspects i believe ?