Main Air Conditioning System Components (Overview)

WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.

There are five main components in the system:

evaporator
receiver drier
compressor
condenser
choke valve.

The system is filled with a suitable quantity of refrigerant and oil.

The system has both a low and high pressure side. These are divided by the compressor and the choke valve.

The evaporator is located on the low pressure side and the condenser is on the high pressure side.

The air conditioning system functions only at outside temperatures above approximately 0-5°C (32-41°F) (varies depending on the type of system). At lower temperatures the pressure in the system is too low and the compressor is not engaged.

Evaporator (=air heated heat exchanger)

In the evaporator the heat is transferred from the warm air (the heat is "cooled") to the cold refrigerant.

The refrigerant then begins to boil and is converted to gas form (evaporates).

The blower fan increases the air flow through the evaporator.

NOTE: In most systems, the blower fan must be operating before the air conditioning system can be engaged.

Receiver drier

The receiver drier has a number of tasks, such as collecting and binding the moisture (water) in the system.

The receiver drier is located on either the low pressure or the high pressure side, depending on the type of system.

Compressor

Sucks refrigerant in gas form from the evaporator.

Compresses the refrigerant thereby increasing its pressure and temperature. The heated refrigerant in gas form passes on to the condenser.

Condenser (= air cooled heat exchanger)

At the condenser, the heat is transferred from the refrigerant to the colder outside air.

The refrigerant then condenses and changes into liquid form.

In most systems there is an electrical fan which increases the air flow through the condenser. This increases the transfer of heat from the refrigerant to the outside air. This of course also increases the capacity of the air conditioning system.

Choke valve

Downstream of the choke valve is the refrigerant in liquid form at high pressure.

The choke valve regulates the amount of refrigerant that flows into the evaporator.