Hello users,
Did someone found a strange phenomena that is : the direct radiation for a surface of 90° slope is greater than its total radiation, or even this direct radiation is greater than the extraterrestrial radiation sometimes in winter in the type15s. If we just watch the type15, its another output "direct normal radiation (not interpolated)" is in sometimes greater than the extraterrestrial radiation. It's strange for me or maybe i don't understand really the solar radiation.
Can someone explain it to me?
Yujun