We are stuck because of the terms of design DNI which changes according to location. What is the difference between available DNI (kwh/m2.year) and design DNI (W/m2 )? Both of them are meteorological data. How can I interpret relationship available DNI between design DNI?
SAM uses the solar radiation data in the weather file that you choose on the Location and Resource page to calculate the solar irradiance incident on the solar field during simulations.
The reference weather conditions are used for field sizing calculations. For a description of the design parameters, please see "Reference Weather Conditions for Field Sizing" in the "Solar Multiple" topic in SAM's Help system, which you can find under "Parabolic Trough" in the table of contents. To open the Help system, start SAM, and either click one of the Help buttons or press the F1 key (Command ? in OS X).
