johank

Hi, Would it be possible to create a new output variable for rear-side irradiance before shadings and IAM? This would more closely model the rear-side irradiance seen by a sensor and allow for more accurate performance evaluations on measured data. See related discussion here: https://forum.pvsyst.com/topic/2508-does-bkglobinc-variable-include-rear-side-shading-loss Many thanks!

... late to +1 but absolutely agree. For modeling performance from built systems (with measured data), sub-hourly clipping losses can be very large. For predictive models, you'd also need high-res meteo data. Not much available yet afaik, but looks to be coming more and more.

... right, clearly did not read that closely enough: it's the minimum ratio that was causing the error. As dtarin said above, the definition is different depending on which settings you're in: Advanced parameters: "shading scene active area" / "system definition active area". Project settings: "system active area" / "shading scene active area" (I think) Setting lower minimum ratios in advanced settings made the error go away. Yay!

Gotcha, thanks Stéphane. In that case it seems like the custom "Maximum Field/Shadings Area Ratio" (80.0) from my example above isn't being used: field / shading area = 174683 / 6189 ~= 28.2

Never mind, I re-created the conversion protocol (.mef) from scratch and now all appears to be well. Apologies for briefly reviving this thread, didn't appreciate how old it was.

Stumbled upon this post after running into issues importing measured POA data (GlobInc) from a tracking system. The reverse-Hay transposition is giving very high AM DHI readings, see att. Is this something that isn't fully implemented yet or am I doing something wrong? The "measured global" shown in the chart looks correct. Thanks!

Thanks dtarin! I have it set up as in the attached, the "80.0" for this project was a test to see if changing the parameter by-project made any difference (it did not). Stephane, thanks for the reply - how is the ratio calculated? I'm OK with a high ratio here, as it just needs to be a representative tracker block (for a large tracking array). There are no significant external shadings.

... as a follow-up: after copy/paste, the warning changed to "area ... is slightly lower" (i.e. no longer blocks running the sim) with a ratio of ~7. Running PVsyst 7.2.11 (24303).

Hi, I have purposely set a high field/shadings area ratio but still get an error that "The area of the 3D fields is lower than the area of the modules defined in the subarrays." See screenshots - I think the ratio here is ~28, below the project's / default limit. Thanks!

Hi PVsyst team, (Apologies if this exists & I missed it-) it would be great to set default Report Options (which pages are printed) globally in Preferences rather than having to specify for each report. E.g. I usually do not print "special diagrams" etc. Thanks!

When importing a project, if prompted to overwrite existing files (e.g. .OND, .PAN etc. already in PVsyst workspace) the project will not import successfully unless I click "Yes to All". If "No to All" is clicked, no further message appears and nothing appears to be imported. Overwriting a single existing file - e.g. clicking "yes" on the first prompt, then "No to All" on the next - first gives the "Projects successfully imported" message but follows with the error message: "Can't open the file: [path]\[project].prj File not found" I would expect it to import regardless of whether or not existing / duplicate files are re-imported. Thanks! PS - projects I've attempted to import were all created with PVsyst 6.

Got it, thanks. Is the rear IAM loss captured in one of the output variables? Finally found the help section discussing it, sounds like it always uses the "Fresnel-Glass" (non-AR) profile to calculate rear IAM loss.

Thanks! So just confirming - it is after shadings, but no other losses are taken out of GlobBak? Would it be possible to add an "after losses" variable, something like GlobBakEff? And have GlobBak be the "before losses" rear irradiance, analogous to GlobInc. That seems more in line with how the front irradiance chain is handled. In the meantime seems just adding BackShd to GlobBak gives you the before shadings irradiance. I think it'd be worth clarifying in the variables definition in the help that GlobBak is after shadings.

Thanks dtarin. I only recently learned that GlobBak is after shading (and IAM?). Would it be possible to split out irradiance before / after losses are applied? As far as I'm aware then there's currently not a rear-side parameter that corresponds to GlobInc. Having that would be very useful for performance monitoring & the like. See also this post by jmallineni.

Thanks for the reply! Much appreciated. I assume the loss %s shown in the Iso-shadings diagram are calculated from the "according to strings" shading factors/table derated by the electrical effect %. Will have to try to confirm this at some point.