Car Air Conditioner

How A Car Air Conditioner OR Car A/C Works?

 | 7 minutes read

Car Air-Conditioner (Car A/C): Background

In the 60s, the car air conditioner was considered a luxury. So, at that time, only about 20% of cars in the USA used to have it. However, in the late 20th century, the manufacturers widely started offering the car A/C. Today, almost every car has it. The car A/C works in two cycles: Refrigeration and Evaporative Cooling (evaporation and condensation). The main purpose of the car air conditioner is to make the cabin ambiance comfortable for the occupants.

Car Air Conditioner Refrigeration Circuit
Car Air-Conditioner Refrigeration Circuit

Firstly, Air Conditioning is the process of making the air comfortable for the car’s occupants. The engineers achieve this by making changes in air’s properties. This mainly includes its temperature and humidity. An air conditioner is a device that changes and controls the properties of air. Basically, it improves the air quality and its thermal condition. A car air conditioner also does the same. Now, let’s understand the working of the Refrigeration Cycle employed in modern-day car A/Cs.

Just like the home A/C, the car air conditioner works on the same principle. It has the following main components:

  1. Compressor
  2. Condenser
  3. Receiver Dryer
  4. Expansion Valve
  5. Evaporator Coil

Car Air Conditioning system circulates the refrigerant under pressure through these five major components in a closed circuit. At these points in the system, the refrigerant undergoes preset pressure and temperature changes. Basically, the Car Air Conditioner has two different circuits. One is circulating the A/C refrigerant (cooling gas), while the other circulates the cabin air.

1.The Compressor of the Car Air Conditioner:

The refrigeration gas circulates within the closed Refrigeration Circuit. It enters the compressor, which compresses it further. This increases both its temperature & pressure. The compressor draws the low-pressure refrigerant gas through the suction valve (low side). It then pressurizes the hot refrigerant and increases its pressure. The compressor then forces it through the discharge valve (high side) into the condenser. The A/C compressor uses a magnetic clutch to connect and disconnect the compressor from the engine. The compressor then pushes the compressed gas to the condenser unit.

Subros AC compressor
Subros AC compressor (Courtesy: Subros)

2.Condensor of the Car Air Conditioner:

The condenser is located at the front of the vehicle. It sits behind the front grill and in front of the car’s radiator; facing the wind. Ambient air passing through the condenser removes the heat from the circulating refrigerant. Thus, the refrigerant converts from gas to liquid.

AC Condenser Unit
AC Condenser Unit

The condenser unit looks and works very similar to the engine radiator. It absorbs the heat from the hot refrigerant. Then, it converts the high-pressure gas into the high-pressure liquid refrigerant.

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