[TRNSYS-users] type 30 (shading mask)

[Federico Bava via TRNSYS-users]

Hello everyone,
I was going through the code of type 30, to understand how it calculates the shadow effect.
But I don't follow some of the passages
Especially I lose its logic when it calculates  xl8 (ps: I assume 0 as slope of ground, so flat horizontal soil).

xl8 = (bb**2. + xl6**2.)**0.5

where bb seems to be the collector height projected in the vertical direction,
and xl6 the row distance between two rows decreased by the projection of a collector in the horizontal direction.
So xl8 seems to me like the distance between the bottom of the collector in the second row and the top of the collector in the first row. But first of all, this distance is not in the x-direction (despite the name xl8) and the way xl8 is used in the following lines are completely non-sense to me, like for example when it defines:

svfgr1 = ((xl6-xl5) + (xl7-xl8)) / (2.*hcl)

Thanks in advance for any help you can provide,

Federico
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