dtarin

+1 for this feature

Are rear IAM losses included when computing the bifacial PR?

The purpose would be to allow the inverter to be limited below nameplate power (which is not uncommon), and also allow a grid limitation to be applied at the POI. This is easily implemented in excel, and should also be able to be implemented in PVsyst.

When testing, the measurement device(s) is likely to not be directly behind structural elements. If PVsyst can calculate the shading and IAM loss separately, could we not take GlobBak before shading and IAM losses, and use the measured irradiance to replace/correspond to this value? GlobBak = global irradiance on rear after shading and IAM GlobIncBak = global irradiance on rear before shading and IAM In this way for testing, we have a variable that corresponds to something somewhat represented by the measurement apparatus. And in terms of importing that data, PVsyst could then use this new variable to be replaced with measured data.

The thin objects in your scene will have the box checked labeling them as a thin object, and the trees will not. The software will calculate shading from cables as a thin object, and trees with the according to strings setting. As for what % to use, different folks will provide different answers. It is dependent on the technology, the nature of the tree shading, how modules are installed relative to the shading, etc. Typically it will be between 70% and 100% for according to strings. Most of the time I am modeling with 100% so as not to underestimate shading losses.

Any graphics driver updates recently?

Yes When you open the PVsyst report, and export the loss diagram (export > Loss diagram values), it states "Global effective energy"

You can modify in advanced parameters. There might be conflict in PVsyst between the setting shown in project settings and the setting in advanced parameters, they are referenced in opposite ways (shading/field vs field/shade). I have always modified in advanced settings with no issues.

Some of these loss assumptions can be defined in advanced parameters from the main menu. When they are updated here, you can check the default box under Detailed losses to set them. Note that module quality factor (when using the default button) will take into account the tolerance assumption set in PVsyst and what is declared in the PAN file. Default wiring resistance = DC loss LID mismatch module quality loss

Correct me if I am wrong, but you can manually calculate the correct PR by including the rear-side irradiance. For a vertical system, this is necessary since the rear-irradiance contribution is significant, and you will likely have irradiance instrumentation on both sides of the module in a constructed facility.

IAM data is the easiest to identify. Low light data (if included) and resistances would be other items, but it is less obvious as to what is correct or not. They will have an impact on production if not properly accounted for.

GlobEff is front side irradiance only after loss considerations (IAM, shading, soiling, etc). To get total irradiance as requested, you need to add the rear side irradiance gain * bifaciality to GlobEff. If you export your waterfall to excel, it will include additional information not shown in the report. It will show you GlobEff and it will also show you GlobEff + backside irradiance, labeled Global effective energy. @PVsyst admin, it would be helpful to rename one of these terms, as the same name is being applied to two different variables.

Understood, however, it is more time consuming to go through each item one at a time on sites with challenging topography and several items. If there is a revamp, displaying all at once and highlighting the modules would be helpful.

Thank you for the reply. The concern is not with development, but the inability to run two subversions at the same time. It is not possible to properly investigate new versions for differences in production or report issues to support while still being able to carry out work responsibilities should we encounter any errors in the updated version. As it stands, I need a second license on a second machine to run two in parallel.

Yes.

There is a bug from 7.2.9 to 7.2.11, see https://forum.pvsyst.com/viewtopic.php?f=4&t=5669. Very problematic, I downgraded to 7.2.6 until it is resolved.

It is showing you the loss there of 0.1%. Set the combiner distance to 0.6m to enable the optimization box to minimize copper mass. it has little effect on the result.

Run both simulations separately, then add the energy in excel. You will need to recalculate things like capacity factor, yield, etc. based on the total plant size. For other parameters such as PR, POA, and the waterfall losses, you will need to use a weighted average to determine these.

If you still cannot get it, try making each distinct orientation a separate group in the shade scene, then try the method stephane has stated.

Your best bet is to reach out to enphase directly.

Getting this in 7.2.11. Cannot save as new variant to resolve, or create a new shade scene; problem still persists.

Your modules are too close together. Create spacing between modules, and make sure there are no other objects penetrating the modules. You can use "Check Scene Validity" under tools to identify the modules that are impacted.

Create two subarrays. In the OND file, add 10 mppt inputs and resave the OND file. Check the multi mppt, on the 235 subarray, set the mppt input to 1, on the 310W array set it to 9.

That is correct; albedo concerns albedo irradiance. Correct Yes in fixed tilt systems there will always be a beam loss (for multi row systems). The electrical losses are separate from irradiance losses, however. One or more tracking manufacturer(s) have presented half-cell backtracking optimization, however I do not know what PVsyst is currently working on as far as implementing the more advanced backtracking methods in the market (I do not work for PVsyst). Implementing backtracking for every single table in the shade scene would be nice, but I am sure there are challenges with doing so.

Inverter losses due to temperature derating will be captured in Inverter Loss over Nominal Power if the OND file has defined a temperature derating curve. Verify that the OND file does and it matches the inverter spec sheet. PVsyst will not break these temperature related losses out separately, but with some work in excel, you could determine the hours and amount of clipping coming from temperature derates.