Car Air Conditioner
Car air conditioners use refrigerating machines for air cooling in the car. Components of motor-car conditioners system include:
- Refrigeration compressor motor.
- Capacitor located in front of the radiator.
- Liquid line, refrigerant management.
- Evaporator.
- Fan.
- The duct system to circulate the air inside the car.
Temperature control is mainly based on the temperature of the air passing through the evaporator. Fig. 20-27 illustrates a typical automobile air-conditioner. Air conditioning moving vehicle is some problems which are not present in traditional residential or commercial installation. The compressor is driven by the engine. Therefore, its speed will change as change the speed of the engine. Cooling system capacity can take care of the cooling load under the most adverse temperature and speed conditions. As a result, under normal conditions, the system has much more features than you need.
This problem is solved with the magnetic coupling in the compressor drive pulley hub.
This clutch is controlled by a thermostat. When passenger compartment temperature is down to the desired level, thermostat releases the clutch. Compressor stops. When cooled again necessary, electromagnetic coupling connects the compressor. Compressor draws power from the engine when the magnetic clutch is engaged. Cutout switch shuts down the compressor at greater power needed for acceleration.
There is another problem with air-conditioned vehicle. The evaporator is condensed moisture from the air. If the evaporator temperature is maintained at or below the freezing point, this moisture will freeze and adhere to the evaporator. Soon, the evaporator will be completely frozen. The air cannot circulate through it. This problem is solved by placing regulation suction valve on the suction line. This valve keeps the pressure in the evaporator just above the boiling pressure, temperature of the refrigerant in the evaporator would cause moisture to freeze the surface of the evaporator. The preceding description of automotive air conditioners were brief.
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Air-Conditioning 
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