Did you model with the unlimited sheds method in the Orientation menu? The electrical effect loss is not shown in the backtracking version's waterfall. I would double check you have modeled shadings properly for both cases. Even when electrical loss is zero, it still displays in the waterfall in v6.78. Either using the unlimited sheds method, or constructing a shade scene and using the "according to module strings" option (more accurate method).
In the "Orientation" menu, I selected "Horiz. axis unlimited trackers" in "Field type". Due to this, I cannot opt for neither "Linear shading" nor "According to module strings" in "Near shadings" box. (As soon as I draw a construction in "Construction/Perspective", it changes the orientation setup in "Field type" automatically.)
And I assume that the electrical loss get influenced only by "backtracking" option in my case since I did not change nothing but "backtracking" in orientation tab.
These two statements are in agreement and say the same thing. Backtracking reduces POA but lowers shading losses. The reports confirm this. "Total irradiance received" = global incident in collector plane.
I understood "It should be noted that the Backtracking doesn't increase the total irradiance received." can be translated into "Backtracking reduces POA" confirmed by the simulation report.
Make sure you have properly modeled these with regards to shading. If you have a very low GCR, it is possible your shading losses without backtracking are such that the POA gain is higher than the shading loss incurred. Location may be a factor, you have very high irradiance; might be something unique to your location.
Any suggestion to correct the shading setup in my simulation? ("Horiz. axis unlimited trackers"). The GCR value applied to all the reports was 41.7%.
I tested the annual energy yield comparsions by the following and found out some interesting arguments:
GCR /without backtracking/ with backtracking/ Diff.
83,30%/ 29,6 / 29,5 / 0,1
41,70%/ 34,8 / 34,6 / 0,2
20,80%/ 36,3 / 36,4 / -0,1
13,90% /36,8 / 36,9 / -0,1
83,30%/ 34,5 / 32,2 / 2,3
41,70%/ 38 / 37,1 / 0,9
20,80%/ 39,2 / 38,9 / 0,3
13,90%/ 39,5 / 39,4 / 0,1
By this result, backtracking application depends on at least GCR and geo-dependent climate whether apply or not. In my case, bifacial with backtracking wouldn't be effective as other places, would it?
And regarding to the location-dependency, I will check out further.
Thanks for your help, Solarguru