dkourk

You are right, globlnc now almost matches! I still have a big difference from what I would expect based on actual nearby data but at least we got to the bottom of this!! Any idea what could cause such a difference between expectations based on last 2 years of actual nearby data and simulation? To be more exact, I have a 0,5MW PV fixed tilt station that is 2kms away from the simulated location and last two years produced an average of 1750Kwh/Kwp/year. I would assume installing one axis N-S trackers would uplift production by about 15%-20%. Now in the simulation with a couple of different meteo files (solcast TMT and meteonorm 8.1 synthetic) we start from a specific production without tracker of c. 1530 KWh/Kwp and then when having trackers with range between 1687Kwh/jkwp for the 3d scene (a 10% difference vs fixed tilt) and 1799kwh/kwp/year for the generic unlimited trackers simulation. Overall I am trying to figure what I am doing wrong and cannot simulate more accurately. - Is it that the meteo files I have do not support the actual data from last two years - and even so, why does the 3d scene defined simulation only produces a 10% uplift with the trackers? Any guidance would be much appreciated!!

Maybe the loss diagrams, attached, could help guiding in what is driving this difference?

Hi, thanks for the reply, I have tried using backtracking and not. it did not make that much of a difference. Also have tried running the same meteo file and again not a significant difference. The difference seems to be coming from introducing a 3d scene but cannot figure out what I am doing wrong or what the parameter of significance is. This is a rather big difference to not understand and could be the difference in the project being viable or not. Your help and guidance in figuring this out is much appreciated! I am attaching the 3d scene and orientation settings in case you can spot something wrong as I do not have the knowledge or experience to get to the bottom of this 🙂 tnx, DK

I am new to PVSyst and have a problem understanding where some significant differences in GlobInc are coming between two different simulations for the same site. One is simplistic and does not use a 3d scene and the other has a defined PV array and 3d scene. I would expect maybe to see some reductions in production from the detail in the simulation but here I have a significant difference that I need to make sense off. , not sure if I should open a new thread though. The orientation is optimal N-S in the 3d scene and I see no material losses from shading. The starting value of the Globlinc is materially different and I think this is what produces a very low specific production for the 3d scene simulation vs the simplistic one and vs some actual data from a nearby fixed tilt PV that I have data for. It might be worth noting I am using a different meteo file for the two, however the starting point (GlobHor) is very similar so I do not think this is the cause of the difference. Any help, guidance or explanation on what I am doing wrong would be much appreciated. tnx, DK

I am new to PVSyst and have a similar problem, not sure if I should open a new thread though. I have made to simulations for the same site. One has a defined 3d scene, the other does not and uses standard settings. This is a one axis N-S tracking system where I get a significant difference in the GlobInc values (almost 20% lower without the 3d scene) and cannot figure out why. The orientation is optimal N-S in the 3d scene and I see no material losses from shading. The starting value of the Globlinc is materially different and I think this is what produces a very low specific production for the 3d scene simulation. It might be worth noting I am using a different meteo file for the two, however the starting point (GlobHor) is very similar so I do not think this is the cause of the difference. Any help, guidance or explanation on what I am doing wrong would be much appreciated. tnx, DK