Hi Joe,
On Item 2, it turns out that the optical efficiency value on the SCA/HCE page is correct. There is a hidden term in the calculation that depends on whether the receiver parameters are for one with broken glass. For receivers with broken glass, SAM excludes the "dust on envelope" loss from the receiver's optical efficiency calculation. In the default case, Receiver 3 is "2008 Schott PTR 70, Broken Glass."
On Item 3, I guess that equation does not make any sense without the definitions of hlterm1..4. Let's try this (HCE heat losses for Receiver 1):
HCE Heat Losses W/m =
Heat Loss Factor * {
( A0 + A5*WS^2 ) +
( A1 + A6*WS^2 ) * [ 0.5*(Tout + Tin) - Tamb ] +
( A2 + A4*DNI ) * [ (Tout^2 + Tout*Tin + Tin^2)/3 ] +
( A3 * [ (Tout^2 + Tin^2) * (Tout+Tin) / 4 ] }
Where Tamb, DNI, and WS are the "Solar Multiple Reference Conditions," and Tin and Tout are the Solar Field Inlet Temp and Outlet Temp, respectively, all from the Solar Field page.
For the physical trough model, the name of the "Number of SCA/HCE assemblies per loop" variable is csp.dtr.solf.loop. It is an array, and I'm not sure exactly how it works. Its default value is [8,1,1,8,1,1,7,1,1,6,1,1,5,1,1,4,1,1,3,1,1,2,1,1,1]. My guess is that the first element is the number of assemblies, and that the remaining elements are in groups of three for each assembly: SCA type, HCE type, Defocus order. If my hunch is correct, for a single loop, the array would look like [1,1,1,1]. You will have to experiment a little with that array in SamUL to see if you can make it work.
Best regards,
Paul.
