How does A Car Air Conditioner OR Car A/C Works? (2022)

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

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

How does A Car Air Conditioner OR Car A/C Works? (1)

Firstly, Air Conditioning is the process of making the air comfortable for the car’s occupants. The engineers achieve this by making changes in the air’s properties. Thus, it 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. The Car Air Conditioner has two different circuits. One circulates the A/C refrigerant (cooling gas), while the other circulates the cabin air.

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1.The Compressor of the Car Air Conditioner:

The refrigeration gas circulates within the closed Refrigeration Circuit. Next, it enters the compressor, which compresses it further. Finally, it increases both its temperature & pressure. First, the compressor draws the low-pressure refrigerant gas through the suction valve (low side). It then pressurizes the hot refrigerant and increases its pressure. Then, the compressor forces this hot refrigerant through the discharge valve (high side) into the condenser. Next, 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.

How does A Car Air Conditioner OR Car A/C Works? (2)

2.Condensor of the Car Air Conditioner:

The front of the vehicle has a condenser. It sits behind the front grille and 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.

How does A Car Air Conditioner OR Car A/C Works? (3)

The condenser unit looks and works very similar to the engine radiator. First, 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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3.Receiver Dryerof the Car Air Conditioner:

Furthermore, the liquid refrigerant moves onto the Receiver Drier. It also contains a filter and a desiccant. Receiver Drier filters out the impurities and removes the moisture from the refrigerant. It also serves as a temporary storage tank for the liquid refrigerant.

How does A Car Air Conditioner OR Car A/C Works? (4)

4.Expansion Valve of the Car Air Conditioner:

The high-pressure liquid refrigerant then flows to the expansion valve. As the refrigerant passes through the valve, it becomes low temperature, low-pressure liquid, and vapor. Finally, the expansion valve sprays the refrigerant into the evaporator in the mist form. This valve controls the amount of refrigerant entering the evaporator.

How does A Car Air Conditioner OR Car A/C Works? (5)

5.The evaporator of the Car Air conditioner:

The low-pressure liquid immediately starts to boil and vaporizes as it enters the evaporator. A temperature sensor at the evaporator outlet controls the expansion valve. (If the outlet temperature is too high, it indicates that sufficient refrigerant is not reaching the evaporator. Thus, it will result in poor cooling of the cabin).

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How does A Car Air Conditioner OR Car A/C Works? (6)

The temperature sensor sends the signal to open/close the expansion valve to achieve the correct flow of the refrigerant. Thus, it enables the A/C to attain the rate and temperature of the evaporator outlet. The foggy mist of the refrigerant then enters the evaporator.

The Air-Flow Circuit:

On the other hand, the car occupants emit heat, which mixes with the cabin air. This warm air enters the evaporator as the blower pushes it from the bottom side. The cabin air passing over the evaporator fins gives up its heat to evaporating refrigerant. Since the refrigerant is colder than the air, it absorbs the heat from the air. Thus, it produces cool air then pushes into the cab interior. The ideal cabin air temperature for humans is around 23 degrees Celsius. Most automatic air conditioners try to achieve it by automatically shutting off/on the a/c compressor and recirculating the cabin air effectively.

How does A Car Air Conditioner OR Car A/C Works? (7)

The moisture in the air condenses upon entering the evaporator. It drops into the drain pan, from which it then drains out of the cabin. The evaporator removes humidity from the air and makes it dry. It passes the cooled air back into the cabin thru the A/C vents provided in the dashboard. Then, the temperature and pressure of the refrigerant drop. It becomes low pressure & low-temperature gas. These low pressure and low-temperature gases again enter the compressor thru’ the suction side, and this cycle repeats.

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The A/C control panel has different features as compared to the home A/C.

It has following modes:

  1. Air on the face only
  2. Air on the face and legs
  3. On the legs only
  4. Air on legs and windscreen
  5. Automatic

Besides, the car air conditioner also has the ‘Recirculation’ and ‘Fresh Air’ modes. Ideally, you should keep this setting in the ‘Recirculation’ mode. It is because, after prolonged use, the air inside the passenger cabin becomes humid and impure. But then, it would help if you turned on the ‘Fresh Air In’ mode. Thus, it lets the outside fresh air enter the cabin and replace the warm/humid air.

How does A Car Air Conditioner OR Car A/C Works? (8)

Thus, A/C makes the cabin air fresh again. In order to ensure efficient cooling and reduce the air drag, it is best to roll up the windows when the A/c is in operation. The air conditioner still cools the cabin with windows open, but slowly.

Most car air conditioners can make the air upto 10 to 15 degrees cooler than the ambient air. However, the modern air conditioning system consumes the engine power significantly. Thus, it could be up to 4-5 Bhp of the engine’s power. Hence, using the Air Conditioner also affects the vehicle’s fuel efficiency. It can reduce the car’s mileage by 1-2 Km/L. Behr and Subros, Valeo, Keihin, Sanden, Aotecar are some of the leading car air conditioner manufacturers for vehicles in the world.

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Refrigerant used in the Car A/C:

The refrigerant is a mixture of liquid that the Refrigeration Cycle uses. It undergoes the transformation phase from liquid to gas and back. The refrigerant is the fluid used in the car’s air conditioning system. The refrigerant transfers the heat as it changes from the liquid state to the gas state. Later, the scientists found that the Freon-R12 gas is the most damaging to the ozone layer. So, modern cars use R134a refrigerant, which is environmentally friendly. However, the emission from car air conditioners is a growing concern because of its impact on climate change.

Tips for using the Car A/C effectively:

  1. Always keep the front grill clear of any obstructions for the proper functioning of the air conditioner.
  2. Always keep the windows rolled up to maximize the efficiency of the A/c.
  3. Keep the air conditioner in the recirculating mode when in use.
  4. Use the ‘Fresh-Air’ mode only when it is necessary.
  5. To improve fuel efficiency, Use the air-conditioner only when it is necessary.

Watch Car Air Conditioner in action here:

Read on: How does the HVAC system Work?>>


How does an air conditioner work simple explanation? ›

As the liquid refrigerant inside the evaporator coil converts to gas, heat from the indoor air is absorbed into the refrigerant, thus cooling the air as it passes over the coil. The indoor unit's blower fan then pumps the chilled air back through the home's ductwork out into the various living areas.

How does air conditioning work in a car UK? ›

When the air conditioning system is switched on, the gas travels to a condenser. Fresh air from outside the vehicle passes over the condenser and the temperature of the gas drops quickly and causes the refrigerant to liquefy.

How does an AC condenser work in a car? ›

Simply put, the condenser will absorb heat in the freon that has been compressed by the compressor and change the freon in the form of a gas into a liquid. This condenser is commonly located at the front of the car radiator.

What is air conditioner short answer? ›

Air-conditioning is that process used to create and maintain certain temperature, relative humidity and air purity conditions in indoor spaces. This process is typically applied to maintain a level of personal comfort.

How AC works step by step? ›

The steps an air conditioner takes to ensure the completion of the cooling process are as follows:
  1. Step 1: The Thermostat Signals The Need For Cooling. ...
  2. Step 2: The Refrigerant Absorbs Heat From Indoor Air. ...
  3. Step 3: Fans Blow Back Cooler Air To The House. ...
  4. Step 4: Heat Within The Refrigerant Is Released Outdoors.
6 Jul 2021

How does an air conditioner compressor work? ›

The air conditioner's compressor works by compressing refrigerant vapour, which increases its pressure and turns it into a hot gas. The cooling/condensing of the hot gas is achieved by drawing ambient air through the condensing coil using a fan, which leaves as hot air.

What is the ideal temperature for car AC? ›

Do not set the air conditioning system too cold and do not direct the airflow directly at your head or neck, as you could easily catch a cold. The ideal temperature is between 22 and 25 degrees.

What are the components of a car AC system? ›

The Five Major Parts of Your Car's A/C System
  • Compressor. The most essential component of any air conditioning system is the compressor. ...
  • Condenser. ...
  • Receiver/Dryer or Accumulator. ...
  • Thermal Expansion Valve or Orifice Tube. ...
  • Evaporator.
16 Mar 2016

Should car air conditioning be on all the time? ›

Rather than open a window and letting in pollution and noise, switching on your air con can have your vehicle cool and fresh in a matter of seconds. That being said, it does not make sense to leave your air con running all the time. In our experience, switching off your air con when you are not using it is a good idea.

Where does the car AC get air from? ›

A: The heating-and-ventilation air intake on most vehicles is at the base of the windshield. This location provides optimum airflow to the cabin while the vehicle is moving. A plastic grille and screen are designed to keep out leaves and other debris, but it's a good idea to clean this area periodically with a vacuum.

Does car AC use fuel or battery? ›

When you're taking full advantage of your vehicle's air conditioner on a hot day in San Francisco traffic, you may wonder, does car AC use gas? Yes: The alternator, which is powered by the engine, is what provides energy to the air conditioner. The engine runs on fuel, meaning you are using up gas when you run the AC.

Is a condenser the same as a compressor? ›

The main difference between the compressor and condenser is indicated by their names, respectively. In a nutshell, the compressor compresses and the condenser condenses. They're processing the exact same thing: the A/C refrigerant.

What are the 4 main components of an AC system? ›

Air Conditioner Components. An air conditioner is made up of many components, but the major parts doing the heavy lifting of moving the air indoors and outdoors are the evaporator, condenser, expansion valve, and compressor. Keep in mind they're each either located outside (the hot side) or inside (the cool side).

How did the first air conditioner work? ›

Willis Carrier, a 25-year-old experimental engineer, created a primitive cooling system to reduce humidity around the printer. He used an industrial fan to blow air over steam coils filled with cold water; the excess humidity would then condense on the coils and produce cooled air.

What are the types of air conditioner? ›

The Different Types of Air Conditioning Systems
  • Window Air Conditioners.
  • Portable Air Conditioners.
  • Wall Hung Split or Multi Head Split Air Conditioners.
  • Ducted Air Conditioning.
  • Air Conditioners For a Diverse Range of Situations.
27 Nov 2020

Which gas is used in AC? ›

Freon is a non-combustible gas that is used as a refrigerant in air conditioning applications. This freon undergoes an evaporation process over and over again to help produce cool air that can be circulated throughout your AC system.

What is the cycle of air conditioning? ›

For this reason, all air conditioners use the same cycle of compression, condensation, expansion, and evaporation in a closed circuit. The same refrigerant is used to move the heat from one area, to cool this area, and to expel this heat in another area.

Does car AC compressor run all the time? ›

If you have auto-climate control on, the AC compressor will run continuously, summer and winter, if the auto-climate control is on any setting other than off.

How do I test my car AC compressor? ›

Car AC Not Cooling - How To Easily Check AC Compressor - YouTube

What type of compressor is used in car AC? ›

The piston type is the most common. This type contains swash plate technology and wobble plate technology. For the rotary type, vane and scroll technologies are used. Valeo compressor technologies are identified under three names: DKV, DKS and DCS.

How does the air conditioner work in the summer? ›

So how does a typical air conditioning unit work and keep you sane during the heat of summer? The basic concept is that a chemical called a refrigerant loops from inside the home to outside and back again, absorbing and casting out heat in the process.

What is the function of air conditioner? ›

Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling the humidity of internal air.

How does an air conditioning unit work during cold days? ›

A regular air conditioner transfers heat from a hot environment (indoors) to a cooler environment (outdoors). This system is all well and good in the summers. But in the winter months, a heat pump extracts heat from the outdoor and transfer it to the indoor. To do that, the air conditioner has to work in reverse.

Why does AC release water? ›

It's because of moisture condensation along the evaporator coil. Cold refrigerant moves through the evaporator coil, which draws heat from the air to cool it down for the rest of the house. As the refrigerant evaporates in the coil, it also causes moisture in the air to condense along the coil.

Which mode is best for car AC? ›

The recirculation mode is comparatively better. But, if you use it for long, the air inside will become impure. So, during long journeys, you can switch to the fresh air mode once in a while to let fresh air in.

What temperature is best for AC? ›

According to the Department of Energy1, 78° Fahrenheit is the sweet spot for air conditioners to balance energy savings and comfort when people are at home and need cooling.

What temperature should AC be set at in summer? ›

You want to be comfortable this summer without spending a lot of money on air conditioning, right? While you ultimately must decide what temperature you feel comfortable at, the US Department of Energy and Energy Star suggest that the best AC temperature is 78°F for summer days.

What are the 4 main components of an AC system? ›

Air Conditioner Components. An air conditioner is made up of many components, but the major parts doing the heavy lifting of moving the air indoors and outdoors are the evaporator, condenser, expansion valve, and compressor. Keep in mind they're each either located outside (the hot side) or inside (the cool side).

Which gas is used in AC? ›

Freon is a non-combustible gas that is used as a refrigerant in air conditioning applications. This freon undergoes an evaporation process over and over again to help produce cool air that can be circulated throughout your AC system.

What are the four major functions of automotive air conditioning? ›

The most essential component of any air conditioning system is the compressor. Your nice, cool air depends on it!
1. Compressor
  • Pressurizing the refrigerant to cool the air.
  • Sensing temperature changes inside and outside your car.
  • Monitoring and controlling temperature output.
  • Moving air to the condenser.
16 Mar 2016

Will car AC work if it is cold outside? ›

Your A/C refrigerant system is totally protected in cold temperatures. Note: I'm assuming you have the recirculation setting (inside/outside) set to Fresh outside air. The recirc/inside/Cabin air setting is bad to be using in cold weather, particularly if its raining or snowing outside.

Can you turn AC on when cold? ›

Some HVAC (heating, ventilation, and air conditioning) manufacturers recommend users refrain from turning on their AC when the outdoor temperature is lower than 59 degrees Fahrenheit. Running it when it's cold can damage the machine. If this happens, you may encounter more problems once the weather gets hotter.

Does outside temperature affect car air conditioner? ›

The hotter it is outside, the harder the air conditioning in your vehicle has to work. Rising outside temperatures put extra strain on your entire vehicle and its cooling system, from the battery and belts to hoses and fluids, requiring each part to work overtime to keep your vehicle cool.

Can I drink AC water? ›

The water from the AC are "good water", generally speaking, and "pure", because they have no salts or residue solids in them. They are basically distilled water. They contain some Co2 which is dissolved in them. With proper filter system we can get very cheap clean drinking water.

Does car AC need water? ›

Water Outside the Car

The system cools the cabin by pulling humidity from the air, and that moisture needs a place to go! Technically speaking, the A/C's evaporator core condenses the humidity (turns it into a liquid). The liquid then exits the car onto the pavement via the evaporator drain.

What is AC water called? ›

Air conditioners pull warm and humid indoor air over a coil of cold tubing. This coil is colder than the air because it's filled with cold refrigerant. The moisture vapor suspended in the air condenses on the cold coil. The resulting liquid water is called condensate, and it drips off the coil and into a pan below it.


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