Problem with energy simulation results when PV panels are installed


I followed the tutorial (,57.98453229968504) (using select by type to define the surface for PV installation) to simulate the PV electricity generation.

However, under this setting, the more I installed the PV panels on the rooftop, the higher the cooling consumption is.

I also reviewed the simulation results when I define a detached surface as a PV installation area and the simulation results show that the more panels installed, the lower the energy consumption by cooling (PV panels as a shading surface, makes more sense).

May I ask what is the reason for the increment in cooling energy consumption when I install more panels on rooftop?

Thanks a lot.