Yes I know, most people will run an APU to run the aircraft's own a/c, but we have reasons for not doing that (specifically a lot of energy intensive kit on the jet that also needs to run on the ground, and the APU hasn't enough grunt to do both).
Would it be easier to find a a way to power the "other things" so the APU
could deal with a/c?
I realize that there could be certification issues etc on power delivery that might be harder than for external a/c.