This system uses an expansion valve to control refrigerant flow and and cycles the compressor clutch to control evaporator temperature. An air conditioning system has two parts each with a different pressure. The high pressure side starts at the compressor discharge, goes through the condenser and the drier and to the Expansion valve. The low pressure side starts at the output of the expansion valve, goes through the evaporator and back to the compressor. A well designed air conditioning system should not have a drop in pressure due to too small of lines.
Lets take a look at the refrigerant path and the components.
The compressor is the heart of the air conditioning system. The compressor is mounted on the engine and is belt driven. At the front of the compressor is a magnetic clutch which when given power engages the compressor. The compressor is the heart of the air conditioning system, it pumps refrigerant in a closed loop through the system. The moving refrigerant moves heat from inside the vehicle to outside the vehicle.