When asked how car air conditioning systems work, most people would respond, “I don’t care how they work. I just want them to work!” While that may be a common response, it does not answer the question. If you are someone who has always been curious about how car AC works. Continue reading below for a deeper look into air-conditioner theory. System components and system operation.

How Does AC Work in a Car?  

The car AC works by manipulating refrigerant between a liquid and a gaseous state. As the refrigerant changes states, it absorbs heat and humidity from the vehicle and allows the system to give off cool, dry air.

 To change the refrigerant between a liquid and a gaseous state. The air-conditioning system works to control pressure and temperature.

 AC System Refrigerants

 In the past, automotive air condition systems used R-12 as the refrigerant. R-12 (aka Freon) is a very effective CFC-based (chlorofluorocarbon). The refrigerant is not flammable and not poisonous to humans. During the late 1980s, scientists discovered that widespread usage of R-12 was damaging the earth’s ozone layer.

 Manufacturers transitioned to R-134a in the mid-1990s. R-134a is an HFC-based (hydrofluorocarbon). The refrigerant does not have the ozone-destroying properties of R-12/Freon. The newest refrigerant is R-1234yf, which produces fewer greenhouse gases. Europe requires the use of R-1234yf, and it will likely be the new standard in the United States soon.

 Car AC System Parts

 Automotive air-conditioning systems have a few key components. Listed below are the main parts and their roles:




 The power unit of the system that separates the low-pressure side from the high-pressure side

 Takes in low-pressure gas and compresses it into high-temperature/high-pressure gas. Mounted to the front of the engine and driven by the serpentine belt


 Reduces the temperature of the refrigerant while it maintains high pressure. Refrigerant changes from a gaseous state to a liquid state as it cools

 Similar to the engine radiator, it uses forced air (fan or vehicle movement) to transfer heat. Mounted in front of the vehicle, behind the grill


 Removes water from the refrigerant using a desiccant (drying agent). Has some system-filtering properties. Mounted on the high-pressure side of the system, between condenser and metering device

 Metering Device

 Either expansion valve or fixed orifice tube. Lowers refrigerant pressure, which quickly drops the refrigerant temperature. Refrigerant is still in liquid form after leaving the metering device. Mounted on the high-pressure side of the system, between dryer and firewall


 The refrigerant changes back to gaseous state in the evaporator, causing a cooling effect. Cabin air is cooled and dried as it blows across the evaporator. Only component mounted inside the passenger compartment, behind the dashboard

Path and characteristics of refrigerant

  •  Low-temperature/low-pressure refrigerant enters the compressor (gas).
  •  High-temperature/high-pressure refrigerant leaves the compressor (gas).
  •  The refrigerant cools and converts to liquid in the condenser. Still under high pressure.
  •  The receiver/dryer removes water from the refrigerant.
  •  The expansion valve reduces refrigerant pressure.
  •  Refrigerant converts back to a gaseous state in the evaporator.
  •  Absorbs heat; when air blows across the evaporator, it is cool and dry.

Common AC System Failures

 Because automotive air-conditioning systems operate under pressure. They need to remain completely sealed from the surrounding environment. Anything that allows the refrigerant to escape or contaminants to enter can cause a failure.

 If a leak is present in any component. Simply recharging the system with new refrigerant will be at best a temporary fix. Identify the leak, and replace the faulty component. Then evacuate and recharge the system.

 Not only will a system leak stop the AC system from cooling, but it can also damage the compressor. The compressor can overheat and damage itself by trying to run with too little refrigerant in the system. Compressors generally are not serviceable and are an expensive item to replace.

 To operate, the car’s AC condenser needs a steady flow of air through its fins. Road debris and dirt may reduce airflow, causing system malfunction. The condenser is mounted directly behind the vehicle grille. Leaving it somewhat exposed and at risk for partial blockage.

Why should you service your Car AC?

 AC is placed inside a cabin and it helps to relax the atmosphere to make humans fatigue-free. Additionally, must be for the health of human beings as it balances the temperature of your body. But when you are looking for the car AC, it is for the following reasons:

When a vehicle is in a congested state, passengers have to face a lot of traffic and due to this. The car’s speed usually slows down. This is why vehicles come with an equipped system to provide a comfort zone to passengers.

Summers are usually hot and humid and that’s why driving in the car becomes quite difficult. So, an effective AC system in the car will maintain the cool temperature in the car and make the environment humid-free.

AC doesn’t only maintain a cool environment. It also filters the air which is quite important in polluted cities. This protects you from hazardous air pollution and health issues. In winters, cars usually face problems due to fog as it makes it difficult to look outside the mirror. That’s why we require AC to normalize the inside temperature and maintain your safety.

 Most countries face a lot of climate changes, which can cause some serious health issues. So AC in the car will maintain the comfort zone and make their journey smooth. Due to these problems, almost every car comes with the AC and we can’t even imagine our drives without it.

When we talk about the working of Car AC, all its components work together and make your ride comforting. So before jumping into the process. It’s a very important component.

Service your Car AC Today!

Car Air Conditioning helps in making our ride comfortable and worthwhile. There are many different components of AC. If there is some kind of defect in any component of the AC, then it will stop working. So get it inspected from time to time. We hope now you know everything about the working of the car’s AC. Let us know in the comments if we missed something about the car AC working. visit our website for more info: Bharat Industry 


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