direct solar gain unexposed windows

I am really new user and I have a problem - or maybe I don`t understand the function of 'Direct Solar Gain (Qg)' of the Thermal Analysis.

I have 3 themal zones. They have only windows on one side. It should simulate different type of facades in a highrise building.
If the windows are orientated North, they collect almost the same amount of energy from Direct Solar Gain if they are orientated South! The 'Solar exposure' and the Annual Sun Path shows that there can not be a direct sun radiation if the windows are orientated North but the 'thermal analysis' don`t want to 'listen'.

I have uploaded the file, please take a look at and give me some advice what I am doing wrong!

Thank you!