How does a cars Air Conditioning system work?

Hey, In this animation I explain the basics of how a vehicles AC system works. I make reference to the pressure inside the system which is really important for the system to work correctly.
On average you should have approximately 1.2 - 2bar (17 - 29 PSI) on the low pressure side and approximately 10 -15bar (145 - 217 PSI) on the high pressure side. This is with the system running.
On a static system (off) you should measure approximately 5bar (72 PSI) of pressure on both the high and low pressure side.
In natural form the AC gas R134a is a gas and has a boiling point of - 26.5oC at atmospheric pressure.
A high pressure is used to change the state of the gas into a liquid. This is because a substance absorbs heat when its converted from a gas to a liquid.
The refrigerant circulates in the closed circuit, continually alternating changing from a liquid to a gas and vice versa. The refrigerant is:
Compressed in the gaseous state,
Condensed through heat dissipation and
Evaporated through pressure reduction and heat absorption.
Cool air is not produced, heat is extracted from the air flow in the vehicle.
All vehicle AC systems will lose some gas over a period of time and its recommended to have the system serviced regularly. I would recommend every 2-3 years.
I hope you enjoy this explanation and if you have a question please ask.
#Airconditioning
#AC
#HVAC
#engine
#howitworks
#GarageTech
#cars
#Animation

[@kennethjones2849]

I watched about 5 videos on AC --even one from a professional institution--yours is the best so far--thanks.

[@dr.yahyaelewa1628]

Strongly agree.. thank you.

[@aaronmcdonald4944]

Also checkout Donut media YT Channel. I like their animations too. this one is very well done btw

[@djecklinyprimon3705]

Can’t agree more!! Excellent explanation 😄

[@subhamoybanerjee3172]

good show, specifically because it is animated keeping all the parts in exact position of a car. that makes this video different from others. keep it up.

[@mariosugay5618]

what happened to the dryer after the refrigerant passes through the condenser?

[@hectorheath9742]

Good to see some actual temp and gas figures. Greatly helps in understanding. Thanks.

[@Silkroads733]

Great I’m a qualified mechanical engineer and auto electrical technician, and I never really knew about to much about a/c units until watching this video thanks, I’m more old scool..from the points ignition and carburettors ect ect..from the 70s..

[@dr.yahyaelewa1628]

Hats lift up Professor. I love your dialect and the way you teach. You are kindly asked to hold a seminar for teachers to teach them how to teach. If it's in my hands, I honor you an OSCAR. Hopefully, your Excellency would accept my kind and deep regards. Once again, thank you so, so much. Your proud student.

[@vladdunareanu8500]

I was curious how A/C works and I found this explanation exactly on my car :)

[@CASP_ian]

One small correction: Dryer is used to remove any unwanted water (or water vapour) and also acts a filter. Water vapour is really bad as it freeze in expansion valve causing starvation.

[@user-kq6ky5tz7v]

the best "How does it work? " I've ever seen thumbs up

[@aniketdeshmukh836]

I have never seen such a big mistake in explanation. Gaseous refrigerant is entering the evaporator instead of liquid refrigerant.

[@IronWarrior95]

@@aniketdeshmukh836 he said gas enters the evaporator, not liquid. But as I read, his mistake is, that it actually is liquid when it enters the evaporator and cools the air down. A liquid cooling air down sounds more effective than a gas cooling air down. And then on its way back when it gets warmer it gets into gas again. I'm actually not sure about it right now.

[@prashantjagtap_17]

I learnt it was way back in 2014-15(engineering days)....But that time I was confused regarding this topic, finally I got the solution... The way u r explaining pressure & temp. at perticular point is just clear all the daught. Thanks

[@NishitShukla]

All Indian engineers are like you, they pass exams without understanding much, the system is such.

[@prashantjagtap_17]

@@NishitShukla Right. They only focus on how to get numbers.

[@NishitShukla]

@@prashantjagtap_17 My father was B Tech Mechanical, he retired as Chief Engg, Damodar Valley Corp, ran a 780 MW plant, but I don't think he knew how the thermal power plant ran. 😁😄. I am into Economics, even I don't understand how the economy works😁😄

[@prashantjagtap_17]

@@NishitShukla 😀 Ok. This month I got selected in Johnson control as a design engineer, and the main product of company is HVAC, so I suppose to know all things about that so try to learnt this after selection 😅😜

[@NishitShukla]

@@prashantjagtap_17 Good luck man😁😄. I am confident that you will never be the one to invent fb, twitter, google or for that matter anything that can be called invention. The last major invention from India was lavan bhaskar churna.

[@seinlanda5492]

Without a doubt THE BEST video about this so far, others talk a lot about details in the compressor and shit but they haven't even explained how does the system works.

[@GarageTechAutomotive]

🙏🏽

[@bridew]

Wow, after many videos finally one that explains with the actual numbers... Thanks

[@DannyOh1984]

Perfectly explained. From the animations to explanations. Thank you very much! Cheers from USA

[@nasapayrollsystem8701]

At the expansion valve , it doesn't boil the liquid to make it a gas . The physics is , if you suddenly compress a gas it will generate heat .. (Compressor) If a gas suddenly expands , and hence drops in pressure it will cool down, enough to make ice. If you open a valve at the end of a Compressor tank , as the compressed air leaves, and expands you will feel the metal outlet getting colder , and it may form ice , depending . This is also only the cooling part of the A/c .... The gas expands , drops in pressure , as you mentioned , and this is the cooling effect , its transfer of energy really .. a full system would include that as the warm air is cooled over the evaporator, It cannot hold as much moisture . Warm air holds more moisture than cold air , this will reduce the dew point and water will be separated from the air. Resulting in cooler dryer air. This water can be dumped out the bottom of the vehicle.. Don't freak out if you have water dripping from underneath your vehicle after a journey on a hot day , with the A/C on ..it's just this condensate being dribbled out

[@nasapayrollsystem8701]

Im probably being a Twat pointing that out though ...😒

[@Redtooth75]

Its both. When the refrigerant vaporizes it absorbs a lot of heat to do so. Something vaporizing is a endothermic process that absorbs heat. Thats why we sweat, the water on our skin evaporating absorbs heat from our body.

[@godwin7733]

I was watch so many videos but i can't understand anything about Ac working. But your video was awesome . Very knowledgeable animatic explanation. Very Good 😍😘

[@relaxationclub3848]

Very straightforward explanation. I feel intelligent now 😅

[@buythisnow935]

You made a mistake about when the high pressure and high temperature Liquid leaves the expansion valve . It stays in liquid form but low pressure and low temperature It evaporate inside the evaporator due to warm air passing thru the fins of the evaporator.

[@uawpittjr211]

🏆 I agree

[@akupehsluarketatAR]

meanwhile in mother russia, the weather cools the a/c system

[@teravolt6113]

I wonder how many people in cold weather countries such as Russia (or Canada, Sweden, Finland...) get seized compressors for not being able to run AC for long long times...

[@anonymousfuck9320]

TeraVolt Not all cars automatically turns of the ac so in some you can have the ac on

[@infinitewisdom4557]

Yep, conventional A/C, in reverse!

[@domisualk6122]

And the Motor warms the Person... the co2 warms russia so everything OK.

[@LuciferMorningstar-ix3lb]

@@teravolt6113 they turn on the heater

[@bunnatang]

your voice is too low. but music is like a thunder.

[@hegotaspare]

Yeah don't forget to turn the volume down after he's finished or you/I will jump.

[@CL0WN]

@@hegotaspare I was prepared and still jumped wtf us that sound design .

[@NAaPALM51]

The guy: I’ll put music at the end 🥁🎸😋 Me now: 🧏🏽‍♂️

[@namihiko8678]

Just one mistake, if the temperature of the refrigerant is 0C going into the evaporator, then it must be warmer when leaving. Since Cabin air is what warms it, then the temperature of the refrigerant as it enters the compressor is probably around 20C (since it has be to less than ambient air temperature) and not 0C

[@gmt-kg4sd]

I think there was a mistake made. When the high temperature passes through the expansion valve, it remains in liquid form until the hot air from inside the car is blown over the evaporator and THEN it turns into a gas. Am I wrong?

[@Anstroy95]

you are right

[@muhammadawais7597]

Yes. When it passes through the expansion valve, the liquid becomes low temp and low pressure liquid and it remains in liquid form as it passes through evaporator where fan blows air over it and it exchanges heat with the cool liquid and convert that liquid into gas which flows back to compressor and that air which was cooled is provided inside the car.

[@JoseJimenez-mf9wd]

Correct

[@glasser2819]

he clearly said that it is the LOW PRESSURE THAT BOILS OFF THE LIQUID INTO A GAS. The TXV regulate the inlet amount of liquid based on evaporator exit temperature. The most important factor is the PRESSURE DIFFERENCE crested by the compressor suction side vs high side. TIP: Simply *Wrap* the liquid line between the front condenser to the TXV with insulation so the high pressure refrigerant is NOT REHEATED by the HOT ENGINE. This wrap drastically improve efficiency in summer traffic 👍🏻 (cooler return line needs to stay exposed to get fully expended back into a gas even in winter during defrost operation)

[@K0nst4nt1n96]

G Lasser already wrapped from the factory on mine.

[@miguelito9va]

Great video. Congratulations!!! I work in automotive industry and I have to thank you for sharing your acknowledge with us.

[@rogerhamberg1266]

Thankyou for busting my hearing after the end of actual video.

[@dr.yahyaelewa1628]

Hats lift up from America to you Sir. Thank you so, so much. Kind regards Sir.🎓

[@supdream8979]

A little technical but I got it how it works great explanation 😃

[@dr.yahyaelewa1628]

I love your dialect Sir. It reminds me with my lovely British Professor .. Blessings. Once again, thank you. Kind regards.

[@ChristianEssentials101]

Great explanation and animation.

[@raquelojeda8311]

Really good video. I have always had a lot of trouble understanding the theory behind it so actually seeing the flow really helped. Thanks a lot 👍

[@travelwithhasan1]

Thank you brother I want to know a little more detail about how cooling is circulated inside the car.

[@sionak]

nice video but two things: the function of the drier isn’t to keep the refrigerant as a liquid, it is there to remove water from the system and to act as a liquid refrigerant reservoir. also when the refrigerant passes through the expansion valve, is doesn’t cool because it boils. it boils because the pressure drops, (if you compress a liquid it’s boiling point increases, which is why it can be a liquid at 16 bar in the pressure side). it is the expansion of the refrigerant through the expansion valve that creates the cooling, not the boiling of the refrigerant.

[@CHIBA280CRV]

That is a Fantastic and simple explanation of how the refrigerant works in a compressed state.. what I can't seem to find is a video explaining how the electronics side of the system works ? Like what happens when you push the a/ c button on the dash ? Sends a signal to what and what pressure sensor those and fan clutch closes etc. ... Which intern leads to the video you just presented.. thanks I hope you have a video on it , and if not would you make one ? It's good to understand how the whole A/C system works. I need to know in order to try and repair my 2007 Honda CR-V a/c system .. I need to understand how it works from when you push the button.. Sorry for the long comment. Thanks again.

[@BillySBC]

Very good video and explanation, as well as indicating the directional flow of the gas in the system. I am getting high pressure on the low side so I'm thinking it's probably the expansion valve now as this seems to be the place where the high pressure drops to lower pressure. Thanks again for posting this.

[@prak44]

Very good explanation.

[@benomac13]

Isn't the receiver dryer used to remove moisture from the system? Not gas

[@solidworksegscorporatetrai3983]

Great Video of Technically Published about an inside mechanism HVAC System of car. Very Useful...

[@garirclinic2020]

The best video on ac ever in my opinion ....thnx

[@pgm7035]

Best a/c demo.

[@desiefiautoelectrician7150]

I watch all your videos with pleasure and learn a lot. Thank you for sharing your experience with us.

[@MrMagsimus]

Fantastic video to break a complicated process down into lay mans terms and deliver excellent commentary 👍🇬🇧👌👌

[@joenaz4311]

Fantastic video. Top tier visuals and thoroughly but succinctly explained!

[@abdulsamad-oz4lw]

Good illustration how it work. Now i can clean my coil with coil cleaner with confident.

[@joelsagayanatan2325]

U made it to understand very easily , while comparing to other videos .. thanks 👏

[@ravindrajoshi78]

Please add more details on how compressor run from engine and how air travels inside cabin,

[@akarshbn]

@Garage tech, on the return circuit, is it not the hotter gas that comes back to the compressor? Not the cold gas as mentioned in the video. If it was cold gas, it was not required to be circulated back to the compressor. It should be hot enough to continue to be a gas but not hot enough for heat transfer with atmosphere which is why gas is compressed and sent to the condensor.

[@junkitlow]

Very detail explains, great knowledge

[@mechanicalengineeringpract140]

Good explained

[@anasrauf5854]

What a video … simply marvelous expalanation❤

[@deepakmandloi2246]

How much may load torque(Nm) occurs on the engine when we turn on the AC system?

[@hyderalitaj1]

could you please upload a video about the electrical side of ac system?compressor engagement ac fan working,about the pressure switch circuits.ac switch.like those. thank you.

[@normalkullanc1993]

Nice and clean thank you

[@pufarinu]

fascinating animation/explanation !

[@niallenglish3777]

Nice 1. Told me exactly wha I wanted t know, and jus had t watch 1 time. Good on ya

[@alizainsomani1127]

Great video well explained and easy to understand with animations and placements of the AC components

[@swapnilbandgar8730]

is there any arrangement to keep compressor speed constant or is it directly driven by engine and its speed varies in proportion to engine speed?

[@coppertechnologies5051]

Your presentation is highly appreciated... Thanks for the work

[@emrekaplan5737]

I am beginner with driving. When I turn on the cooler I turn on the A/C button as well. Do I need to turn on the A/C button when I turn on heating or should I leave A/C button off?

[@droneboy5415]

When u want heat leave the ac button off

[@theSilvioRoesler]

Such great video, thanks for putting this together

[@kensonmalupande2424]

Well explained

[@bakerbk3696]

Question: I have a van with seats at the back but no AC vents what can I do to get some cool air to my kids sitting behind me. Thanks a million

[@MrGbabineau]

Expansion valve does not turn liquid refrigerant into a gas. It turns it into a low pressure liquid then passes thru the evaporator extracts the heat from the air and then It is turned into a low pressure gas then back to the compressor.

[@Redtooth75]

No, the expansion valve creates a pressure differential. There is a high pressure on the condenser side and low pressure on the evaporator side. When the liquid high pressure freon goes through the expansion valve and hits the low pressure it evaporates into a gas. The evaporation is an endothermic process which is what provides the cooling.

[@jahidkhan396]

Please show the heating system also what we are using in winter season

[@hoatruong6691]

Super easy to understand. Thank you a lotttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt

[@akstarkids]

Good information 👍

[@Imjeevabharathi]

Extraordinary bro

[@GilNgai]

Excellent animations and explanation!! How do-able is building an AC system into a non AC car? (or transferring a system from one car to another?)

[@GarageTechAutomotive]

It’s achievable but would be a lot of work, best thing to do would be to have another car the same which has AC and swap over all the parts. Dash board and heater controls, heater box and matrix, plus all the AC hoses, condenser , AC compressor, different crankshaft pulley and belt. May even need to have the Engine ECU coded so it can keep the rpm up on idle when switched on. It would be a lot of work and you’d have to question is it really worth it.

[@footballCartoon91]

@4:51 Why is that a generally Warm liquid refrigerant (55 degree celsius with 16 bar of pressure) When turned into vapour it becomes cold at 3bar of pressure. And how does they make the system suddenly have 3 bar of pressure? Sorry I'm confused

[@YasirKhan-zr1un]

Hello, Its a nice video with detailed insight of the AC system. Just wondering you or anyone else here can suggest with the situation I have with my car. I have Mercedes W203 1.8 Petrol auto 2006 model. AC was running fine while i was driving and then I switched on the climate control which set the AC to full speed, i used it for 5 minutes and then turned off the climate control. After that AC stopped cooling. I refilled the gas twice also but still it doesn't blow cool air anymore, Can you suggest what part in the AC system is potentially not working here and how can I check it ?

[@arcadesunday4592]

You ever find the answer to this ? I have an Opel which exhibits strange / similar issues... I had the compressor refurbished, and it worked for a while, but seems like the problem is back (only a few months later). I've taken the car back to the workshop, and they may have refurbished it (again - second time) but seems like the problem is back (ie: no cold air). I think the compressor is losing pressure, or the expansion valve is not working. I really don't know!

[@OfficialDjSideAffex]

Great video

[@moolatakhilesh]

Will the compressor cut in and cut off depending upon the temperature inside ? How that works ? Normally in the air con system once the temperature is attained a solenoid valve will close the flow of refrigerant and due to low pressure cut off switch the compressor will switch off.

[@der_cumsportler1022]

How is the Compressor affected by the rpm of the engine? It looks like it has a fixed ratio but then the power of the Compressor rises with higher speed? How does the AC regulate the cooling power at high speed travel?

[@wildlog]

Beautiful explanation. Can I ask how aircon makes air dry inside? And why aircon smells inside? As per explanation sounds to me like a closed system.

[@notmenotme614]

I’ve one question… At 0:10 why is the car sat off-road in the middle of a desert?

[@GarageTechAutomotive]

Hahaha adds to the illusion of high outside temperature ☀️🏖️😎

[@jasonalcide8478]

this is the first time im really understanding wats it all about ....tanx

[@devanandkunduru4560]

That's awesome explanation

[@larrymcinnis3530]

My 2007 Ford Taurus shows good static pressure but the clutch doesn’t engage so I jump the relay the clutch engages but the pressure on the low and high side goes way too high. The low side almost goes all the way to the gauge limit as does the high side? Any ideas?

[@mkumar9613]

good explanation man.. keep doing more work like this!!! Great job

[@latbat58]

How does the liquid boils into gas but also loses temperature?

[@GarageTechAutomotive]

Hey, it’s all down to chemistry, the natural boiling point of AC gas is between -26 to -30 degrees Celsius, depending on which one is used as there’s a few. When the gas boils it absorbs the surrounding hear which lowers the ambient air temperature by about 15•c

[@veritasomar]

Excellent explanation and video! Could you tell me please which software you used for the animation. Was it Solid Works or something more specific to the automotive industry?

[@arcadesunday4592]

I think this video was borrowed from VW tech training or something! Very good animation though!

[@hughdoyle8612]

How do I know if I have put enough refrigerant in. I was able to put in 2 - 6oz cans of R134a. which dropped the temperature from in 90 degree F to 45degree F. I have not tried my oil analyser yet as it says to wait 24 hours.

[@wodeyaeric5351]

Where is refrigerant stored among the three--compressor,evaporator and the bulk head?

[@mrddurian3453]

Thank you for the great video, it helped me a lot. 👍

[@ryans413]

One things wrong on this video the blower fan doesn’t blow hot heat from outside over the evaporator. The blow fan in cars is usually in the dash the condenser coil is where all the hot heat is takin away. The blower fan just blows the cold air off the evaporator since it’s already a gas and cold no cooling down will happen like the fans on the condenser. Why the condenser are outside the home or the cars cabin cause they take the hot heat away

[@cvr689]

Do manually AC units in cars cut-offs when they reach the desired temperature as like Climate control or don't?

[@MC-ph7gr]

Does the a/c clutch stay engaged all the time when the a/c is on and the car is working on park gear on idle (Altima 2010)? Thx

[@muzeyicharles19]

I would like to understand....is it by the connection of the compressor to the engine or by electricity from the battery ...how does it work ...

[@SportCenterBovec]

Hello Mr. Thank you for this explanation, very nice, but I didn't got the answer I was looking for. Maybe you can help me... Last winter I had my mechanic install an air conditioner in a van I converted into a camper. I barely got the original for the second installation (VW T4 - year 1995). The air conditioner works (cools down a lot), but the cooling stops after some time. Condensation (approx. 1 dl) appeared under the passenger's feet a few times, and the second time, after approx. 20 minutes, approx. 0.5 - 1 l of condensate spilled under the van. In principle, I have found that the time lag between switching on and stopping cooling is related to external humidity. The mechanic has already inspected the drain - clean. Refilled, checked exhaust temperatures, etc., everything should look OK. The situation is still the same. He mentioned something “rheostat” or something like that to be replaced ... I don’t know, the air conditioner was bought new, a kit. What is your opinion, do you already have any experience with these climates (VW T4, l. 95)? I myself suspect that after a certain time the condensate freezes somewhere and consequently has nothing to blow out. But when it thaws, it all flows into the drain and something passes at once. According to my logic, only a fine setting of all parameters is needed (if there is a thermostat for real defrosting ...)? What do you think? Thank you for your time nd your answers. Greetings!

[@Sangeenair]

When the Low temperature passes through Expansion Valve doesn't it remains liquid.That is a low temperature low pressure liquid..And when the fan throws the ambient hot air the liquid refrigerant absorbs the heat and only then converts to gas??

[@aussieboy77]

I think you're right.

[@5Siver]

abhishek nair exactly

[@ryans450]

In a conventional AC system the expansion valve turns it into a liquid/gas mixture. Not sure if it is different in automotive

[@teravolt6113]

The only different thing with automotive is that TEVs belong to the block type (internally equalized, internal sensing bulb). Some liquid may convert into gas even when the fan is off as soon as the evaporator is warm, but the evaporator would soon become ice cold and the expansion valve then experiences trouble in keeping that liquid from exiting from the evaporator even though it struggles to do that... the biggest issue however is not with that little amount of liquid that may well evaporate inside the suction pipe before the compressor, but the expansion valve closing up too much and doing 3 bad things: 1)depriving the compressor of the lubrication flow (not such a big issue when the compressor has a sump however, but automotive compressors nearly never feature one) 2)driving the high side pressure too high 3)driving the low side pressure too low and therefore increasing the compression ratio too much and making the compressor overheat...

[@hedgehogthesonic3181]

I don't think that's right, what if the ambient temperature is the same or lower than the gas temperature? it will not turn to gas? the compressor can't receive liquid to compress it, only gas. The time the refrigerant leaves the thermostatic expansion valve it changes from liquid to gas.

[@gabrielv.4358]

How does the compressor handles high rpm's? Does the valve lets more fluid flow, or does the cooling fan from the radiator helps it maintain a steady pressure inside the system? I know it has 2 modes, the normal and the max speed fan. Will it cool more if I maintain the engine at higher rpm's too? Thanks!

[@HansraRulez]

Is there any way that we can run AC when engine is not running? Like running compressor on additional battery powered motor?

[@allseasonadventures5124]

Awesome job man, thanks

[@virmankoe8390]

I like your video..i want too know if i can put the condensor in a standing formation...so cold gas wil go from te underside vertical following te condesor line..to get out from the underside heading to the drier reciever..if its possible..wil it harm mij compressor about its oil which we put it in for the working condition..my engine room has not enough place to out is horizontal..so i want to place it vertical..looking forward for youre answer

[@dan.youtube]

Considering that AC means Air Conditioning, not just Air Cooling, how does cabin HEAT work with regard to this process? Is air from the heater fan routed directly into the cabin, bypassing the evaporator? Or what?

[@eduardm1301]

Nice video. So it means when the AC is not cold anymore it could be the condenser or evaporator problem. Is that right?

[@GarageTechAutomotive]

EduardM could be no gas in the system, It may need re-gassing or could have a leak, most commonly because of damage to the condenser from stone chips etc. The compressor could also be faulty.

[@deividasabrutis7248]

So what is holding compressor back until button is pressed? Is there some solenoid in there to disconnect shaft?

[@PhilWithCoffee]

Great video, but was it necessary to blast that music at the end?

[@freshfingersff]

Please I have a problem with my Camry 2008 v6 ac. The cool ac seizes from time to time . When it happens I turn it off and on again . Then I gets cool for 2 mins and seizes again . Wondering is it’s an issue of the compressor sensor or Ac pressure switch , or expansion valve ? There’s no leakage . Please help

[@Tesla.Channel2024.]

What is the coldest temperature a car AC can achieve?

[@marvinfollero846]

props to the animation. great work

[@joetheguitar30]

what are the other potential causes of car overheating other than engine problems? the engine has been fixed, and the AC seems to be cold. When i turn my AC on, it overheats after a few mins of driving and there are smokes under the hood. The mechanic says it could be due to relay or fan problem. Can you shed some light please?

[@DrDIY.]

Does insulating the pipes between the compressor, the condenser and the evaporator help in the over all efficiency of the AC ? I am asking this because my car has these pipes insulated at some sections and not insulated at others.

[@AJ_9202]

Does the high pressure liquid freon turn into gas once it passes through the expansion valve or the evaporator?😊