FRta user defined

For solar water heating:
I have technical data for a Veissmann Vitosol 200F but the manufacturer does not indicate values for FRta or FRUL, I believe they are equivalent to optical efficiency and the heat loss factor k1, respectively. The values are 82% and 4.44 W/m2k. Is that right?
FRta = Optical efficiency?
FRUL = Heat loss factor k1?

Hi Austen,

Please see SAM's Help system for information about the input parameters:

The "Solar Water Heating" topic has a general description of the model (click the Solar Water Heating section heading in the table of contents", and the topic for the Solar Water Heating page has descriptions of the input variables.

For more detailed descriptions of the model, see:

sam.nrel.gov/solar-water-heating

Best regards,
Paul.