"Solar position table" and "Collector incidence angle table"

Dear Gentlemen,

There is a significant difference between the results acc. to the "Solar position table"
and "Collector incidence angle table".
For example, while the annual energy is 6 GW for "Solar position table",
the mensioned value is 9 GW for "Collector incidence angle table".
I duplicated a case and run the new case in the SAM.

Could you please say the possible reason.

Regards,

Dear Rahmi,

The default linear Fresnel case uses the Solar position table option for the collector efficiency table. That option specifies an optical efficiency value for a range of solar azimuth and solar zenith angles as described in the Help topic for the Collector and Receiver page .

If you change the option from Solar position table to Collector incidence angle table, you must also change both the angle values in the table row and column headings, and the optical efficiency values in the table.

Best regards,
Paul.

Dear Rahmi,

If you change the option from "solar position table" to "collector incidence angle table," SAM does not change the angles or efficiency values in the table. When you change the option, you must be sure to also change the angles and efficiency values in the table to represent the field efficiency at different collector incidence angles instead of at different sun angles.

If you change the option without changing the values and run a simulation, SAM assumes that the sun angles preserved from the old table are collector incidence angles, and the results are meaningless.

Best regards,
Paul.

Dear Paul
The default Fresnel molten salt case use 'collector incidense angle',how can I change the angles and efficiency values for 'solar position table' and 'IAM polys'

Dear Bahram1374,

Try exporting the default data from the table in SAM. You can use the exported text file as an example to see how to format your data. When you have a correctly formatted text file with your data, you can import it.

Best regards,
Paul.