When attached to a building, the panels transmit a small amount of the absorbed heat to the building - less than would otherwise be absorbed by the building if the panels were not shading it. The building’s thermal energy is what is being measured, not that of the space including the solar panels.

When in an open space, the panels absorb more heat than would otherwise be reflected out of that space if they were not there, but they contribute to the total thermal energy of that space.