If I were trying to use an old car AC compressor, I would study the design of the newer
Inverter type mini-split ASHP units, and maybe think about using PV to power the motor..
My guess is, a medium sized car would need between 12,000 & 18,000 BTUh..
So, that could be the approximate top limit of your compressor's range.
Here's an 18,000 BTU
Solar Powered Direct Current Air-Conditioner / Heat Pump
that most likely will need about 2kw of PV, depending on your night cooling needs.
DC Air Conditioner: 12 Volt 24 volt 48 Volt DC Air Conditioners DC Solar Air Conditioning
A Bushless EV motor might do the trick.. I'll bet this one could kick out some
HP..
Electric Motorsport EV Parts :: PMAC Motor
But, you would need some major PV to run it..
They make smaller EV bushless motors for bikes and scooters that might work.
Even a large RC bushless motors might work for a low BTU output..
Robot MarketPlace - Power 90 Brushless Outrunner Motor 325 kV