Time Step for SAM Model Simulations

Dear Pablo,

Sorry for all of the frustration. In SAM 2014.1.14, did you change the simulation time step to 15 min? To do that, click "Configure Simulations" (the button next to the green arrow Run button), and then click "Simulator Option" at the top of the window. When you use a weather file with 15-minute time steps, you should change the simulation time step to "15 min".

I don't have a SMW file with sub-hourly data that I can use for testing, but I have requested one from the NREL CSP engineering team.

Best regards,
Paul.

Dear Pablo,
SAM 2014.1.14 only displays hourly results, so it truncates the data beyond 8,760 data rows in the graphs on the Results page. However, the TRNSYS simulation engine generates an output file (text file with the .out extension) that you can find in the temporary folder SAM creates to store simulation data.
After running simulations, you can find the output file while SAM is still running. SAM deletes the temporary files when you close it, so be sure to keep SAM open when you look for the file. For example, on my Windows computer the folder that contains the output file is here:
C:\Users\Paul\AppData\Local\SAMEXE\SAMEXE-Paul-INST1-2014.1.14\simdata
The file has a name that looks like this. It is a text file with tab-delimited data:
New CSP Trough Physical Case 1 STEP 15m ID 171475992.out
There is a standalone version of the SAM 2014.11.24 data viewer called DView 2.0 , but unfortunately it does not seem to read the .out file, perhaps because it is very large (65 MB). I have asked the DView developers about that and will let you know when I hear back from them.
UPDATE: DView 2.0 only reads comma-separated data, so to use it to display data from a .out file, you can replace the tabs with commas. (Future versions of DView will support tab-delimited data.) In case you want to modify other time-series data for DView 2.0, you can find a description of the DView file template format in the DView installation folder (C:\Program Files (x86)\NREL\DView2\SampleFiles).
I found another data viewing program called Kst that might work for viewing the data in the .out file, but I have not used it.
Best regards,

Paul.

 

Dear Arian,

What discrepancy are you seeing between the one-hour and one-minute simulation results?

For hourly simulations, the detailed photovoltaic model uses the midpoint of the time step to calculate the sun position for the hour. For one-minute simulations, the model calculates the sun position for each minute. Could that explain the difference?

Best regards,
Paul.