We've had many of those systems tested in our fleet. You are looking for a zero idle unit.
On triple digit days, crews would idle their trucks to keep the AC on. We tested these systems with the fleet to reduce emissions. I think, with the advent of hybrid vehicles, we stopped testing those types of units. But I'm sure most of those companies are still around. The units typically took up the space of a truck bed cross box. Plus the added plumbing to tie in to the OEM system.
Here is one company we tested.
