A7: Heating & Air Conditioning

Compressor, condenser, expansion device (TXV or orifice tube), and evaporator.

It pumps and pressurizes the refrigerant, raising its temperature and pressure, and circulates it through the system. It separates the low side from the high side.

It removes heat from the high-pressure refrigerant vapor, causing it to condense into a high-pressure liquid. It is located in front of the radiator to get airflow.

The evaporator absorbs heat from the cabin air as the low-pressure liquid refrigerant boils into a vapor, cooling and dehumidifying the air blown into the cabin.

It is the metering/restriction device that drops refrigerant pressure and meters the flow of high-pressure liquid into the low-pressure evaporator, where it can boil and absorb heat.

A TXV varies refrigerant flow based on evaporator temperature/pressure using a sensing bulb, while a fixed orifice tube has a constant-size opening and does not modulate flow.