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How Does it Work / Air Conditioner

How a Car Air Conditioner Works

Air conditioning facilitates the removal of heat from inside the vehicle. The principle applied is that heat is removed by conduction and convention. An evaporator which is cold, absorbs the heat from the air that is passed through it, then cold air is forced out through the vents inside the car by the blower motor. This is done by pressurizing refrigerant (134a) with a compressor and then releasing refrigerant (134a) inside the air conditioner evaporator.

Car Air Conditioner System
Car Air Conditioner System



Some automobiles are equipped with an automatic climate control system to regulate the temperature inside the car automatically. The climate control module is a computer which monitors and adjusts to a temperature set by the user. The temperature is controlled by a combination of cold air from the air conditioner, and hot air from the heater to achieve a desired temperature. The blower motor speed is controlled by a solid state speed controller. This controller electrically controls the speed of the blower motor and replaces the conventional blower motor resistor system.

Typical Air Conditioner System (appearance may very)

The air conditioning and heating unit provides thermal comfort to passengers inside whatever the temperature outside. The air inside can be heated, cooled, disinfected or ventilated. The climate control feature helps to maintain the desired temperature. The system that provides cooling, heating and climate control is known as the HVAC (heating, ventilation, air conditioning) system. Basic principles of fluid mechanics, thermodynamics and heat transfer are control the system. Your climate control settings allow all three to work together to achieve good indoor air quality, thermal comfort and optimal pressure.


Climate Control Center

The climate control system can store trouble codes when a problem is detected in the system. You can retrieve codes by pressing two or more buttons on the control panel at the same time. To find out how to retrieve trouble codes for you vehicle check your owners manual or consult a repair manual. When the code retrieval system is enabled a trouble code will appear on the temperature control head. After repairs have been made the system will need to be re-enabled this is done by disconnecting the battery for 45 seconds and reconnecting the battery. Testing can be aborted at anytime by turning the key to the off position.

Compressor

The air conditioning compressor is the refrigerant pump of the air conditioning system. The compressor compresses refrigerant inside the system and circulates it to the condenser and then to the evaporator. The evaporator is where the pressurized refrigerant is released, causing a drop in pressure resulting in a cold evaporator, the low pressure refrigerant is then returned to the compressor to be re-pressurized. The air conditioning compressor is driven by a drive belt that is powered by the engine and can be engaged and disengaged by an electromagnetic coil on the front of the compressor.


Air Conditioner Compressor
 
To maintain the efficiency of air conditioning system the compressor drive belt should be checked regularly. In case it is worn out or degenerated it should be replaced. The system's hoses should be checked for deterioration, bubbles, cracks and hardening or oily residue, all could be signs of leakage. The correct refrigerant charge should always be maintained, low system refrigerant charge is a common cause of a weak AC system.

Air conditioning odors are developed when a fungus has grown on the evaporator core, warm damp surroundings provided the perfect breeding ground for fungus which grow with moisture. Aerosol disinfectants can be used to avoid this condition, while the air conditioner system is running on the full high setting with recirculation feature activated, spray a disinfectant into the inlet of the ac system (under the dash on the passengers side) the odor can be prevented from returning by repeating this procedure periodically throughout the summer months.
 

Basic Maintenance

a. Automotive charging kits are available at any auto parts store and it is recommended to buy can with red or green refrigerant dye which can help to point out the location of any refrigerant leaks. The kit will have instructions to add the refrigerant safely. Protective eye wear should be used when handling pressurized refrigerant cans.

b. Sometimes bugs, leaves and dust particles can get stuck in the condenser fins. Foreign objects and dirt can be cleaned with the help of a garden hose or compressed air forced through the radiator and condenser backwards until clean.

NOTE:

a. The air conditioning system is always under pressure, until the system is discharged completely, no repairs or disassembly should be performed. Eye protection should always be worn when repairing or servicing the air conditioning system.

How Does it Work / Air Conditioner

Check Manufacturer Specific Air Conditioner Questions and Answers

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