It can be related to as the "Rolls Royce" of air conditioning system. It's a very sophisticated technological air conditioning system based on several principles.

1. Refrigerant only where the refrigerant is the only coolant material in the system( in contrary to the chilled water system, where the refrigerant is used for cooling/heating the water that is circulated throughout the whole system).
2. inverter compressor that allows lowering power consumption with partial cooling/heating loads.
3. Several air handlers(indoor units ) on the same refrigerant loop/circuit.
4. ability of modular expansion