Dear all,
a question about the IAM modifier for the diffuse component: the PVSyst help specifies that this is calculated using an integral over all possible sky directions, and depends only on the tilt of the module. How exactly is this integral calculated for an ASHRAE parametrization? Do the integration limits depend on the plane tilt, or how is the tilt accounted for in the integral?
In addition, the "detailed losses" section in PVSyst gives a diagram of the IAM loss factor depending on the plane tilt (see attached image). I am puzzled as to why the loss factor is almost the same for a tilt of 0 and 90 degrees, given that it is calculated using an integral over all sky directions  shouldn't the visible sky be only half as large for a module tilted 90 degrees?
Thank you very much in advance  all the best
Joe
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