Dear Joe,
As you note, the variable
is an input to the
compute module.
And, in the desktop version of SAM, the variable is shown in the user interface on the Solar Field input page with the label "Actual number of loops," where it is a calculated value rather than an input that you enter.
That is because in the desktop version, you specify the field size either as a desired total aperture area or solar multiple, not explicitly as a number of loops. SAM does its best to determine the number of loops required to achieve either of those desired values based on the collector aperture area and other properties for each collector type on the Collectors input page (
in SSC).
In SSC, the total field size is not an input variable, so you do not need to calculate it. You set the number of loops along with the collector aperture area and other properties.
A good way to see how this works is to create a physical trough case in SAM, and then click
Generate code on the case tab and choose "LK for SDKtool" to create an LK file that you can then open in SDKtool to see how the input variables are set. You can also use that technique to create files in other languages, but a benefit of using LK with the SDKtool is that you can use the Data Container tab to look at the values of all the variables and compare them to the values in the desktop version of SAM.
Best regards,
Paul.
