Hi Ben,
Thank you for sending me your file. It has the following characteristics:
- 15-minute data
- Contains plane-of-array (POA) irradiance data
- Contains data for a few days of the year (June 25 - July 1)
You're on the right track, but instead of setting values for time steps you are not using to zero, I would set them to valid values to avoid the simulation errors. Here's one way to do that:
1. Use the weather file download tools on the Location and Resource page to download a default TMY file from the NSRDB for the site location. That file will contain hourly data with header information appropriate for the site.
2. Run the "Solar Resource Interpolation" macro (click
Macros under the Simulate button) with "Interval Length" set to 15 min. If you just downloaded the file from the NSRDB, it should be selected on the Location and Resource page so you can use the macro's "Location and Resource page" option for "File selected from."
3. Use a spreadsheet program to edit the converted file (The macro should show you where the file is, by default it will be in your <user>/SAM Downloaded Weather Files folder.):
a) Create a "POA" column, and paste data from one of the other columns, maybe from the DNI column to create a complete column.
b) Insert your data into the appropriate rows.
4. In SAM, on the Location and Resource page choose the file in the library.
5. On the Location and Resource page, under "Albedo - Sky Diffuse Model - Irradiance Data (Advanced)", choose either
POA form reference cell or
POA from pyranometer.
6. Run a simulation. You may see a bunch of warning messages about calculated irradiance values that you can ignore.
7. On the Results page, use the
Data tables or
Time series tabs to examine the output data for days of valid data.
We are working on enhancements to SAM to make it possible to work with weather files that contain less than one year's worth of data.
Best regards,
Paul.