Car air conditioning

Car air conditioning is a utility designed to maintain cool conditions in your car as it releases heat to the outside. There are many different models of air conditioners for cars depending on the make of the car or even if you changed your type of air conditioner. Though these air conditioners differ in model and efficiency there are some basic parts found in all air conditioner. These parts are the compressor, the condenser, the evaporator, the expansion valve and the drier/accumulator. The following brief explanations of car air conditioning parts should give you a start on figuring out how air conditioning works. This should also help you understand the jargon that technicians use when describing their diagnosis and what part they are fixing.

Here are some of the functions of the major components in air conditioning:

  • Compressor: This pressurizes and circulates the refrigerant in the system
  • Refrigerant: This carries the heat. It can change state from liquid to gas when it absorbs heat and revert back on cooling.
  • Condenser: This changes the phase of the refrigerant from gas to liquid and can sometimes be fitted with an electric fan and it expels heat removed from the car.
  • Expansion valve (or orifice tube in some vehicles): This is somewhat of a nozzle and functions to simultaneously drop the pressure of the refrigerant liquid, meter its flow, and atomize it. Basically it controls how cool the air you get will be
  • Evaporator: This transfers heat to the refrigerant from the air blown across it, cooling your car.
  • Receiver/dryer: This functions as a filter for the refrigerant/oil, removing moisture and other contaminants and to do this uses filters and desiccant
  • After learning the various parts of the air conditioner it is important to know how it works. Basically the compressor puts the refrigerant under pressure and it changes state from liquid to gas and then goes to the condensing coils. In your car, these coils are generally in front of the radiator. Compressing a gas heats it up. In the condenser, this added heat and the heat the refrigerant picked up in the evaporator is expelled to the air flowing across it from outside the car. When the refrigerant is cooled to its saturation temperature, it will change phase from a gas back into a liquid. The liquid then passes through the expansion valve to the evaporator, the coils inside of your car, where it loses pressure that was added to it in the compressor. This causes some of the liquid to change to a low-pressure gas as it cools the remaining liquid. This two-phase mixture enters the evaporator, and the liquid portion of the refrigerant absorbs the heat from the air across the coil and evaporates. The refrigerant goes through the cycle over and over.

    A compressor clutch is necessary to engage and disengage the compressor cycle. The compressor clutch tells the compressor when to turn on or off so that the refrigerant is correctly pressurized for use by the condenser which is then delivered to the evaporator where the cooling starts.