Ever wondered how you get cool breeze from air conditioner. What is the mechanism actually involved in producing cold air in burning hot summers? Here is the simple diagrammatic explanation of working principle of an air conditioner. No matter what type of air conditioner you are using, windowed, split wall mounted (PTAC), cabinet floor standing or roof top type, basic principle is same for all of them. Even inverter air conditioner that has got modifications in primitive design still follows the same principle and laws of thermodynamics.
Basic Mechanism And Principle

How Air Conditioner Works – Diagram
Explanation: Every air conditioner (also pronounced as AC, A/C or Air Cooler in certain regions of the world) has got a compressor inside it. It works to compress and pump the refrigerant gas. Compression of refrigerant produces heat. To dissipate this heat, compressed refrigerant is pumped to the condenser coils where a fan blows the heat out to outer atmosphere. During this process, refrigerant takes the liquid form. This liquid refrigerant is pumped towards expansion valve. Expansion valve has a temperature sensor connected to it which works in correlation with thermostat settings. Expansion valve releases the appropriate amount of refrigerant to evaporator (cooling coils) where liquefied refrigerant takes gaseous form. Conversion from liquid to gaseous state due to expansion causes cooling because energy is absorbed from the surrounding. Air when passes through fins (attached to coils) gets cooled and blown to the room. The gaseous refrigerant in cooling coils then enters the compressor and gets compressed once again. The cycle continues unless the compressor is shut down.
In a nutshell, air conditioner draws heat from the indoor and releases it to the outdoor. Indoor acts as a source and outdoor as a sink for heat.
In vehicle air conditioners, a Receiver-Drier is installed between condenser and expansion valve. It serves to collect excessive refrigerant when not required for cooling operation. It also has got a desiccant which absorbs any moisture present in the refrigerant.
Inverter air conditioners: These air conditioners use an inverter to control the speed of compressor. Electricity is first rectified to DC (direct current) and then inverted back to required frequency AC (alternating current) using pulse width modulation. Thus compressor speed can increase and decrease according to the room temperature. Such air conditioners are extremely energy efficient and consume approximately 30-60 % less electricity than old fashioned air conditioners. Inverter air conditioners are expensive due to the additional machinery inside them but cost is slowly recovered in electricity bills. Their other advantages include quiet operation, faster cooling, no indoor temperature fluctuations and no voltage peaks caused by compressor.
Air conditioner as a heater: When air conditioner is used as a heater, the process which is shown and explained above just simply gets reversed. As a result of reverse mechanism, hot air is propelled towards indoor and cool air towards outdoor.
Zubby
Nice piece…. Sir, why are some air conditioners mounted high on top and others mounted below on the wall? I wanted to know the difference?
Talal A.
It’s just the difference of design.
Manoj b
Simple and well defined
Saidulu
Sir i have one doubt if ac work with solar panel or not plz explain…….
Talal A.
Yes if you have solar panels setup large enough to generatw power for air conditioning unit.
Narendra Babu
Very simple and good explanation.
pradip
What is the effect of air-conditioning on relative humidity of air in the room?
Talal A.
humidity will decrease in room.
asad mirza
sir can u explain how many types of gases are used in ac compressor and how these work?
Talal A.
HFC, PFC, CO2, N, NH3 etc.
Chinnikalyan
Does it work with out a remote?
mpiima isaac
so what happens when its too cold? and what if i want to maintain a given temperature in the room?
Talal A.
If it’s too cold, traditional heating solutions like electric, gas heaters and radiators work the best. Reversible inverter air conditioners fail to work properly when temperature is sub zero.
Gopal das
How many types of ac???can you explain me which ac is used for what ??and what gas is used in ac??
Baidoo Godfred
why is it that split air conditioners do not use driers ?
Talal A.
These units run dry. Their external units are also placed in shade. So a drier is not usually required to remove moisture from gas.
SATHISH M G
What is the effect of air-conditioning on relative humidity of air in the room?
Arun
1.what is the CO2 acceptance limit in a room or place where AIR conditioner is running??
2.on what basis the selection of window AC differs from Split AC??
*based on Circulation of Air??
*co2 level in a room??
Talal A.
Lower than 500-600 ppm.
Choose split AC if enough space is not available in wall to install windowed AC unit.
These days split air conditioners are preferred over windowed ones.
Arun
Thank You Sir
leonard
Briefly explain the principle of air conditioner. Thanks
Sihuzan
Please explain me briefly how to refill ac
Sihuzan
What part shall I check if ac is not working
Talal A.
Start with plug, check remote batteries, check indoor unit then outdoor.
Saptarshi
Sir,can I retrofit my 2ton multisplit a.c into V.R.F inverter a.c?If yes what spares I have to replace?
jraju
To another query i would ask you further query. Could we ourselves clean the ac without mechanic help. Carbon deposit is one of the thing that to be cleaned. How to find whether ac is properly working. The buzzing sound is the only thing i hear when it is running. Would it auto stop, once the set temperature is reached to stop consuming further power? Hope that you would answer my sub queries
Talal A.
You need to remove and clean the filters of indoor unit. Use air blower to blow off dust from cooling fins. Also clean the outdoor unit with air blower. You can do all this on your own.
When required temperature is attained, inverter A/C slows down its compressor and consumes minimal power to maintain that temperature.
ADEBANJO ADEBISI
the DC that powers the inverter AC compressor is usually of how many volts and secondly if AC is fed to the compressor instead of DC what will happen to the unit?
Talal A.
Compressors of DC inverter air conditioners are fed variable frequency AC to control their speed.
jraju
Hi,
As air conditioner is being used for summer reason, should one call for maintenance if it was running properly? After how many years, one should worry about filling gas in air conditioner?
Talal A.
If you feel cooling is not up to the mark, first service the air conditioner. If it does not improve the cooling then gets its refrigerant gas refilled. Some air conditioners can run years before requiring any gas refill.
You need to periodically clean the indoor and outdoor unit especially indoor units filters to make the A/C work properly. Depends upon dust conditions at your residence.
jraju
It is 2 ton inverter ac from voltas. Normally what is the power consumption of inverter ac of 2 ton capacity in sleep mode. Sleep mode is a kind of auto adjusting the coolness of room and is said to be economical.
Talal A.
Please see its user’s manual or box. Power ratings are mentioned on them.
jraju
Hi, does using two ceiling fans and one pedestal fan consume more electricity than using sleeping mode on inverter ac?
Talal A.
Depends upon power rating of AC. Besides even 1 Ton inverter AC would be consuming more current than 3 fans.
Ajith
Very very Excellent….
srinivasan
sir i am working in shipbuilding ,For our AC plant we are using R404A gas . can we use different mixed gas .y we are not using CO2. kindly explain. and also found some times the compressor frosting . what could be the reason. plz clarify.
Talal A.
CFCs work at much lower pressure than CO2.
Often the frosting on compressor head is normal.
lovneesh
when gases come from high pressure to low pressure produces cooling. On that principle AC works.
Mahmood dalvi
Than where is CFC used…????
Talal A.
Not used anymore.
Anil Raina
Sir, Kindly explain me what must be the characteristics of refrigerant gas by giving some simple examples.i would be very much greatful
muruganantham n
Sir recently i purchase an inverter split ac 1 ton for my room 10sqft but technician installed it without air evacuation by using vaccum pump and told me that it will not effect much, but it is taking long time to cool to 24degree , will u pls guide how to remove air from system which is already in use.thanks.
Ashirvad.
What is the difference between split Ac & windows Ac?
hiten setia
the main principle behind cooling in air conditioners and refrigerators is
1. evaporation
2. compression
3. condensation
4.expansion
Chanchal Kumar Datta
If the outer air contain bad or obnoxious smell (e.g., Fish Market) , can it be eliminated by any type of refrigerator?
muzaffar ali
I want to make AC from home refrigerator. Plz suggest me
Hebergeur
A number of people don’t realise that turning on the air conditioning actually reduces the number of miles per gallon of your car. There is energy used in removing the heat and moisture from the air in the car, and this consumes petrol because of the extra engine load.
ahmed
Sir recently i purchase an invertor split ac 1 ton for my room 10sqft but technician installed it without air evacuation by using vaccum pump and told me that it will not effect much, but it is taking long time to cool to 24degree , will u pls guide how to remove air from system which is already in use.thanks.
Talal A.
It should have been vacuumed before putting it to work. Now you have to live with it.
Charles Mandala
Can the a.c. unit, windowed, work properly with cooler outdoor temps?
pravin patil
how much electricity(in units eg.1 units,2units etc.) will consume by the ac for 12 hrs…
pravin patil
i want to make my sericulture (silkworms)rearing house (always stays between25-27degree celcious) without ac will you please help mi for that….
pravin patil
any other idea do you have related to cool the room without using air conditioner but cooling effect is just like air conditioner..please reply .
G Ravinder Reddy
In airconditioner, air into the room from indoor unit is comming from out side atmosphere or recirculation of the same air of the room clarify my doubt.
How to get fresh air from atmosphere from air conditioner.
Raj
I have a similar question as posted by Karthick, I have recently installed Split ac in bedroom, however I don’t feel fresh and feel heavy when I get-up in the morning. Are there any chances of gas leakage from indoor unit?
Talal A.
No. Just open a window slightly to let fresh air in.
Karthick
Recently i have installed AC in my bedroom. while waking up in the morning, nowadays i am not feeling as fresh as i used to feel before AC installing… is this because of reduced oxygen supply while sleeping…? To supply fresh air what should i do with my AC. PLEASE SUGGEST
Talal A.
That could be because of deficiency of oxygen in closed room. Open a window slightly to let fresh air in.
Hemanth
In any AC system coolant work as just a cooling media it won’t affect the oxygen level unless it has a leakage… coolant, it cools the filtered Air from surrounding ( out the room) and pass over the cooling pipe which gives a cooling effect that’s it….. and if you are not feeling comfortable alter the AC temperature may be due to more cooling effect moisture % may have increased in room…….
Talal A.
You are mixing air conditioner with air cooler. :)
dayo
sir, i have 5tons ac that is displaying E4 what could it be responsible for that, thanks
K K GURURAJA
Does room air conditioners will provide comfort condtion (24°C DBT & 60% RH)?
jay
i want to know more about refrigeration cycle. i have main question that how the refrigerant gas is condensed in the condenser.we already know that in the AC unit, the gas is condensed in the condenser and turns into the liquid and the atmospheric air is used to condense the refrigerant and as you know that the atmospheric air temperature is not constant , so is there any device between the compressor and condenser that block the gas thus the proper amount of pressure of refrigerant gas can be obtain , so that it can reach to the saturation temperature so that the gas can be condensed.
ashok
Hello Sir can I convert a car AC to my bed not bed room .it is just to save electricity thank you
K K GURURAJA
Does room a/c’s are equiped with humidifier and dehumidifier?
Sandy
My Ac got burnt and fire came out what is the reason pls tell I switched all button off and throw water on ac
Talal A.
May be short circuit. You should have installed a circuit breaker with air conditioning unit.