neelesh92

Hi, I am looking for some clarification on how PVsyst treats electrical shade loss with different type of simulations. I have three simulations with same exact loss assumptions,weather file and other global project settings. 1. 1-axis N-S axis tracker (backtracking ON) 2. 1-axis N-S axis tracker (backtracking OFF) 2. Fixed Tilt with 60deg tilt and -90 azimuth (facing East) I have an 8760 output for all three cases above (attached), comparing the output from #1 & #2 and fixed tilt output (#3) for the hours where tracker tilt/azimuth angles matches with fixed tilt (facing east, PhiTilt is 60deg). I then looked at hourly DC energy (Earray), electrical shade loss (ShdElec) and GlobEff which got me to the following questions related to how PVsyst treats electrical shade loss. a. For the same plane tilt (PlTilt), azimuth (PlAzim) and tracker angle (PhiAng), I expect the electrical shade loss (ShdElec) to be the same across all three cases (irrespective of tracker or fixed tilt) with rest of the assumptions being the same. But I am noticing different hourly energy output during these hours (see highlighted columns). Is this something to do with any angle rounding error in backtracking algorithm when plane tilt angles reach the tracker limits? b. Does PVsyst assume zero electrical shade loss based on the value at middle of every hour or is it an average loss reported for a specific hour? It would be of great help to get responses to these questions and understand the shading loss treatment better. Thanks in advance!

Solarguru, Thanks for the response. It looks like some of my rows were not equidistant, albeit repeatedly trying to make it all the same. It did not save the values properly I suppose (Ugghh!). I re-ran the scene and the shading animation works fine, showing zero beam loss. Nevertheless, this is a very important update for users when modeling SAT tracker projects at a variable terrain site. This feature will help quantify the shading losses due to terrain undulations better than before in PVsyst.

Hi, I am looking to model a single-axis tracking (SAT) system with backtracking. I am doing this by placing one field with 'two' tracker rows (reference) and other fields having one 'individual' row. Based on the release notes from 6.7.9 it looks like we can now model backtracking with single tracker rows - "..allowed trackers with a single table to inherit backtracking parameters from the reference tracker.." However, I am still seeing inter-row shading with the set-up described above in a shade scene on the individual tracker rows, with the backtracking parameters (row pitch, collector width etc.,) all being the same for all the rows. Should I be manually selecting a tracker field as reference? or have I misunderstood this new update? Would be great if I can get this clarified. Thanks in advance!

Hello, I'm trying to use different .MET file for each of my batch simulation and also save each of the simulations as a new variant (.vc0, vc1, .vc2.....). I tried checking the 'Create Hourly files" box and specify parameters which produces hourly files for each simulation and also clocked on the "Always produces calculation version files". These settings don't seem to save each simulation as new variants. Please help me figure out how to do this. I'm using PVsyst v 6.47 Thanks in advance! Neelesh

Hello, I am running parametric simulations with two different Meteo files for the same location and all the other system design/loss parameters remain the same. Both the .MET files have same monthly GlobHor and DiffHor values. However, in reviewing the loss diagram I see two different values for the transposition factor in the loss diagram which essentially should stay the same when GHI and DHI are same. Can you please explain the source for the difference in transposition factor? Note, that the only other difference I found with two MET files was the difference in time shift (Average time shift on clear days -- -10 minutes vs - 42 minutes).

I'm trying to create a shade scene for a project that has highlands (mountains/hills) very close to the project site (~2 miles). I'm more inclined to think that this would create a far shading as this obstruction would create a shading effect on the whole system at a given instant. PVsyst help describes to use far shadings when the distance of the obstruction is 10 times the system size, which is not true in my case. Would you consider to model this as near shading or far shading/horizon? Looking forward to get more insights on this question. Thanks in advance!