Getting dates from simulation outputs

Dear Sam,

In general, SAM assumes that the first simulation time step is the first hour of Monday, January 1. (For subhourly data, the time step would be the first 15 min, 10 min, etc. of Monday January 1.) That means that SAM requires a weather file that follows the same convention.

Theandmodules available via the SAM API run a simulation for a single time step, so you could develop your own model that uses a different convention.

The SAM performance models use the row position of the record in the weather file to determine the simulation time step rather than the data in the time step fields. The exception is that the solar performance models use the time stamp data for sun angle calculations, because those calculations require a value for the Julian day. For example, for a weather file with typical year data, the sun angles at 10 am on January 10 for a file that uses 1988 data for January would use the Julian day number for January 10 1988.

As you correctly note, themodule does not include the time stamp data as output. However, themodule does, along with other useful information about the weather file.

Best regards,
Paul.

The wfreader compute module

Hi Sam,

We finally had time to look at this a little more carefully, and it looks like moving the June data in the weather file to beginning of the file should work for what you are trying to do, assuming that the data in the Month, Day, Hour, and optional Minute columns are consistent with the irradiance and meteorological data in each row.

That approach will not work if you use any inputs that are specified as month-by-hour matrices, such as shading losses, or the electricity rate schedules in the financial models. As you suggest, any other hourly data, including shading losses, load data, etc. would need to be consistent with the weather data.

Best regards,
Paul.