dtarin
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Posts posted by dtarin
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Express the report to second decimal to get clear picture, losses could be near zero and are being rounded.
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If there are no trees or objects that shade the modules, backtracking is on, and your system is flat, it will not have electrical shading loss.
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No electrical shading loss is showing. If these are bifacial c-Si, you'll want to include electrical effect (modeled according to strings) and then make the comparison.
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Manually move the modules and objects over the image and line things up that way
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Add an object in the PVC file like a tree line or houses
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GlobInc = POA
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Importing meteo file(s) with CLI requires the user to first create a SIT file from PVsyst, which means importing meteo files is not able to be automated for unique sites. If I have to go in and create a site, I might as well just create the meteo file there which creates a SIT file at the same time for known formats. Is PVsyst planning to add the creation of SIT files within CLI? Importing a csv file and defining an .MEF file to locate name, lat, and long (with each row being a unique site) in the file seems straightforward. This could default to using synthetic meteo to complete the SIT file. Or include lat/long selection in the custom import of MET files where we define data fields (known format weather files typically already have lat/long).
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It is common practice (I think) to ignore this and I would suggest ignoring this, I'd rather have the full area of the table represented when calculating shading loss, rather than changing the size of the table to match module quantity and using a reduced table area (it's this area that determines shading loss after all, not the quantity of modules).
But you can change table size quickly. Determine the lengths associated with each table size according to string size, you can do this by clicking a table, changing the table length according to # of modules, record the length in meters, then go into equipment list, filter for trackers, and filter by length each table type (3/2/1 string), select all of that type and change length. Top picture is before adjust, bottom after, # of modules has decreased after one table swap.
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It should not matter much that there is a difference. The shading losses calculated in the shade scene are applied to the output determined by the system size as it's defined in the system menu. As you've noted, the motor gaps and joint gaps (depending on the manufacturer) are not considered which leads to the discrepancy. You will need to delete tables to get them to equal, but this may not result in a material difference.
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Are there any plans to include the clipping correction button under the known format method? Certain weather data sources provide sub-hourly data in time-series format in a single file, which is useful to import through the known format menu, since it will generate each year automatically into a separate weather files. Otherwise, we will be required to separate the file into 22 files then import through the custom format each file. The other option would be to allow the custom import feature to import more than one year, automatically generating a new file for each year (and not have the menu pop up each time asking the user to check the file, which should come only at the end of the file).
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go into backtracking management menu inside shade scene and set backtracking parameters, and into the diffuse tool in the shade scene and set the selections. there could be general issues with moving to new version
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You can try setting these settings under advanced settings menu to zero and reimport into PVsyst.
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When you multiply a random variable by a constant, the mean gets multiplied by the same constant and the variance gets multiplied by that constant squared. Xi are iid random variables.
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1 hour ago, dtarin said:
For any single year that is the case. For multiple years, the uncertainty due to annual variability decreases, so this parameter needs to be separated out and used with the equation in my previous post, and then
added tocombined with the other uncertainty quantities in full. My example was not quite correct in this regard. -
For any single year that is the case. For multiple years, the uncertainty due to annual variability decreases, so this parameter needs to be separated out and used with the equation in my previous post, and then added to the other uncertainty quantities in full. My example was not quite correct in this regard.
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If your trackers have any N-S tilt it will show tilted axis for the 3D scene. Horizontal axis is orientation type in Pvsyst. You would not want to change it to horiz. axis if your scene is 3D and you want to account for slopes in your tracker tables. Run (or re-run) the shading table, and it should update to tilted axis for Orient/System. You may need to go back into the orientation menu (to make sure it updates there and the tilt updates if it is non-zero average tilt) after generating the shading table , saving it, and exiting the shading menu for it to then update in the orientation menu.
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I calculated 1,253,579,619.69, which is a difference of 0.047%, possibly because your waterfall is only showing the first decimal. It can be displayed to third decimal.
1436079647 1431771408 -0.30% 1315797924 -8.10% 1315797924 0% 1322376914 0.50% 1309153144 -1% 1280351775 -2.20% 1272669665 -0.60% Total 1253579620 -1.50% PVsyst 1254163298 0.047% -
For a single year, σ = 3.11. For two consecutive years, σ = σ / √2
Var( X̄ ) = ( 1/n )^2 * Var( X₁ + X₂ + ... + Xₙ ) = ( 1/n )^2 * ( nσ² ) = σ² / n
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ShdLoss is the total near shading loss, which includes beam, circumsolar, diffuse and albedo components. FShdGl is the global shading loss factor, so 1- FShdGl will give the percentage value. If you wish to calculate from irradiance values, it is (GlobShd/GlobHrz - 1). If your model does not have horizon loss, GlobInc is the denominator.
If you want to identify direct (beam) shading (i.e., from a tree or module), you would use ShdBLss or FShdBm; FShdBm is typical. How to use it depends on your application. For example in capacity testing, it is often suggested to use below 1.0; however, this may not be the best option depending on your plant, which month(s) the test is occurring, etc.
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Your panels are placed with a 25 degree tilt and 0 azimuth onto a sloped terrain, resulting in an effective tilt and azimuth used in the simulation for calculations. This is typical.
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If you are not running specific PV software, such as AutoCAD plugin PVcase or something similar that can easily export from CAD, one way is to export the surface as a collection of points (X,Y,Z) in meters as a CSV file. They will need a screenshot from CAD of the surface and general site boundaries to align the modules within the parcel boundaries. In AutoCAD, the surface topographical lines can be exploded and exported as points easily, using the start or end points from the exploded lines which (in my experience) reduce down to a line segment with three points.
Backtracking Algorithm GCR Differs from Average GCR
in How-to
Posted
PVsyst will often (or always?) default to using the highest GCR under the backtracking menu if you have not selected which tracker(s) to use for backtracking, even if there are only one at say 0.411 vs 0.410. In the shade scene, go into the backtracking menu under tools to select the appropriate tracker for backtracking. There are different options, you can select an individual table (at the pitch you want) or automatic.