How Does an Air Conditioner (AC) Work?


How Does an Air Conditioner (AC) Work?

How Does an Air Conditioner (AC) Work?
Image credit:- Wikipedia

What is air conditioner

Air conditioner is a mechanical device that’s function is to exchange the hot air inside the room with cold air to maintain a desired room temperature. the hot air had originally been collected and passed with a system to cool down.

This processing is primarily done using five components:




Expansion valve



An air conditioner works by collecting hot air from a space, and after processing it within it’s system with the help of a refrigerant an then releasing cool air into the desired space, where the hot air had originally been collected. This is essentially how air conditioners work.

In this article, we will talk about how air conditioners works and what it’s components and how they do work.

Parts of an air conditioner

Air conditioner are mainly two types–
Window air conditioner system
Split air conditioner system.
window systems and split systems  are further classified into mini-split and central systems. In everyday language, these are commonly known  as window ACs and split ACs, respectively.

Photo Credit : ScienceABC

List of all parts installed with the both window and split ACs read below-


An evaporator is very simple and important part of the AC
An evaporators function is to exchange the heat.

An evaporator consists a coil and this coil responsible for collecting heat from the desired space/room and exchange this heat with refrigerant gas.

In the evaporator heat is absorbed by refrigerant gas.
And this refrigerant gas is concerned into the liquid when it exchange the heat with refrigerant gas.

The indoor unit of a split air conditioner. It contains the evaporator coil (Photo Credit : Shutterstock)


Some most common refrigerant gases are used in air conditioning systems like-:
Hydrofluorocarbons or HFCs ( R-410A)
Hydrochlorofluorocarbons or HCFCs ( R-22) 
Hydrocarbons (R-290 and R-600A).

These gas are generally used with ACs,
Because these gas are absorb heat and travel very well in all components for further processing

Like for
Compression, expansion and for condenser.


As it’s name signifies this part is used for compressing the refrigerant of gaseous state.
Compressor compresses the refrigerant which comes from the evaporator.


Condensers basic work is to condence the vaporized refrigerant gas into the liquid refrigerant.

The condenser receives the vaporized refrigerant from the compressor, and after  converting it back to liquid and absorb the heat outside.

AC condenser (Photo Credit : tradekorea)


If we expand the liquid refrigerant gas at we high speed then it drops it’s temperature very fastly.

And in the ACs this expansion process is done by expansion valve and this
Also referred to as the throttling device.
The expansion valve is located between the two  of coils (first from chilled coils of the evaporator and second one is from hot coils of the condenser).

Point may be noted that in the case of window ACs, the three components mentions in above are all located inside a small metal box that is installed in a window opening.

And these are the main components of an air conditioner. Now it’s very important that how a air conditioner works how they work together to make an AC do what it does.

Air conditioner (AC) working principle

How Does an Air Conditioner (AC) Work?
Image credit:- Wikipedia

An air conditioner collects hot air from a given space, processes it within itself with the help of a refrigerant and a lot of coils and then releases cool air into the same desired space where the hot air had originally been collected. This is  how all Air conditioners work.

Many people thinks that an air conditioner produces cooled air with the help of mechineries placed and installed inside it, by this machineries it to cools a room so quickly. So it might also consumes so much electricity.

In reality, however, that’s a misunderstanding that an air conditioner is a magical device and consumes a lot of electricity.

An air conditioner is not a magical device; it is just a combination of  some physical and chemical phenomena that cools a desired space very effectively.

All processes with ACs

To cool down the room it took the warm air drawn inside the ACs through the grille which is installed at the base of the indoor unit, which then flows over pipes (evaporator coil) through in which the refrigerant (i.e., a coolant fluid) is flowing. 

The refrigerant liquid absorbs the heat of this worm air and becomes a hot  itself. And during this process it removes the heat from the air that falls on the evaporator coils.

Note that the evaporator coil not only absorbs heat, but also wrings out moisture from the incoming air, which helps to dehumidify the room.

After absorbing the heat from from room this refrigerant gas become hot and then it passed to the compressor, the compressor compresses the gas so that it becomes so hot, since compressing a gas increases its temperature and pressure.(by increasing it’s temperature we can chill it very effectively)

After leaving the compressor this  hot, high-pressure refrigerant gas then moves to the third component – named condenser. Again, the condenser condense the hot refrigerant gas into liquid and condenses the hot gas so that it becomes a liquid and entered into the expansion valve to expand.

And this refrigerant reaches the condenser as a hot gas, but quickly becomes a cooler liquid because of hot gas is expand at very high rate the heat of the ‘hot gas’ is dissipated to the surroundings through metal fins. So, as the refrigerant leaves the condenser, it loses its heat and becomes a cooler liquid. This flows through an expansion valve –and after the expansion valve  refrigerant entered into the evaporator, so the refrigerant arrives at the point where its journey started.

Here’s a simplified diagram of the air-conditioning process:


When you switch on your AC  and set your desired temperature (like, 24°C/ degrees Celsius) or put it on auto mode, then thermostat installed inside the ACs it senses that there is a difference between the temperature of the room’s air and the temperature that you’ve chosen or pre auto mode.

A thermostat constantly monitors the temperature of the system so that it’s maintained near a user’s desired point. (Photo Credit : Flickr)

(Photo Credit : Ilmari Karonen / Wikipedia)

Although all the components involved in the air-conditioning process in window ACs are located inside the same metal box, the underlying process of cooling remains exactly the same as in split ACs

Parts of a window air conditioner. (Photo Credit : Wikipedia)

This entire process is repeated over and over again and again until the desired temperature is not attained. In a space, an AC unit keeps drawing in warm air and expelling it back into the room until there’s no more warm air left to cool.


Best air conditioner in India – Bijli Bachao

Why ACs needed

Imagine that there is summer season and you’re outside in the sweltering heat of a hot summer day, and there is no shade to save yourself and here you can’t service too much and this heat become too much dangerous because this is most hottest day of that year. However, there is one thing that keeps you going: then you know  that you have air conditioner  inside your home and sudden you moves towards your home after one hour you reach to your home.

Finally, that moment comes. You open the door and take a step inside your home. A gust of chilled air envelops every cell/parts of your body and you instantly feel better. And forget everything what happen with you outside of that hottest summer season day.
And you feel full relax
Just imagine it.

Air conditioners are a great invention for whom wants relax.

I’m dam sure that all of you have had this experience at least  in your lives. The ‘cooling revolution’ that air conditioners brought to human society can never be discounted. Although previous generations had fans and other methods of keeping cool on hot days, they were never as amazingly effective as modern air conditioners in terms of sheer cooling capacity.

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