Air conditioning system for a vehicle with engine-independent cooling

Air conditioning unit comprises a coolant circulation which is divided into two coolant circulations (4a, 4b). An independent claim is also included for a process for operating the air conditioning unit. Preferred Features: A front air conditioning device (2) is arranged in one coolant circulation (4a) and a rear air conditioning device (3) is arranged in the other coolant circulation (4b). A compressor (5, 5b) is arranged in each coolant circulation.