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Automotive Air Conditioning Parts

Typical automotive AC system

If you're familiar with how the refrigerator in your kitchen or the air conditioner in your home works, you will quickly realize that the A/C on an automobile is basically the same system, but more spread out.

How It Works

Automotive air conditioning systems consist of six basic parts, all of which work together to create cold air that is sent into your car's cabin. It works on the simple principal that compressing some gases causes them to heat up.

That heat is released through the condenser, causing some of the compressed gas to become liquid. This liquid is then sent to an evaporator where it quickly loses its pressure, causing some of the liquid to turn back to gas at very low pressure, becoming very cold.

This makes the evaporator very cold and the air that passes over it transfers heat to the evaporator, cooling the air as well. This air goes into the vehicle's cabin, cooling the occupants.

Typical automotive A/C system

The Parts of the A/C System

The six basic components of the air conditioning system in your car are:

  1. The Compressor - which compresses the refrigerant gas (usually R-134a) and causes the refrigerant system's circulation. The compressor is typically run off of the engine by a belt.
  2. The Refrigerant - is the R-134a gas (sometimes R-12 in older systems) that is used as the coolant to compress and release creating and releasing heat.
  3. The Condenser - which quickly changes the phase of the refrigerant from gas to liquid, expelling heat and creating an area colder than the ambient atmosphere.
  4. The Expansion Valve - is the mechanical nozzle that meters the flow of the compressed refrigerant into the condenser, monitoring how it decompresses and atomizes it.
  5. The Evaporator - is where the decompressed, cold refrigerant is sent so that air can be blown across it to be cooled and sent into the car's cabin.
  6. The Receiver/Dryer - is a sort of filter to remove moisture and contaminants from the refrigerant.

The entire A/C system is relatively simple, but handling of refrigerant or emptying/refilling the system requires special licensing and equipment due to the environmental hazards of the refrigerant.

Checking for refrigerant by poking something in the fitting and looking for venting is ILLEGAL as it releases refrigerant into the atmosphere.

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