The air conditioning system in your car is a complex process that requires careful maintenance to ensure it continues to work effectively. The expansion valve or orifice tube is the small hole in the air can that absorbs heat from the cabin and helps to cool the air.

This part of the system is usually located in the passenger cabin with you, instead of by the engine. It's not a radiator, despite its appearance, but rather an essential component that plays a crucial role in absorbing heat from the cabin and transferring it outside. Don't let anyone tell you otherwise!

The refrigerant enters the evaporator coil as a cold, low-pressure liquid and is then heated up by the cabin's heat. This process turns the refrigerant back into a gas, which then moves out of the evaporator and into the passenger compartment, taking the heat with it.

The fan pulls in air from the passenger compartment, and the coils take the heat out of it, cooling the air that is blown into your face. The refrigerant, now in its gaseous state, enters the compressor, where it's pressurized and the process starts all over again.

To prevent damage to the system, there's an accumulator between the evaporator and the compressor that traps any excess liquid before it can get into the compressor. This ensures the refrigerant doesn't turn into ice crystals and causes problems.

The evaporator also takes the humidity out of the air in the car, helping you feel cool and preventing moisture from building up inside the cabin. However, if you notice water dripping underneath when you stop the car, it's likely just water from the A/C evaporator and not a cause for concern... unless it's oil or blood, which would be a different story!

Refrigerant doesn't last forever, so if you want your car's A/C to blow cold, you'll need to add some refrigerant. While we're on the subject, let's demonstrate how to recharge your A/C.

So, I was hoping to grab one of those recharge kits, and I have a friend who has a ton of technicians who know what they're doing if I need any help. I'm a science guy, so I think I can handle it... but we'll see about that!

Is the recharge kit here? No, there it is! Let's get started. If you notice your A/C blowing a little hot, you can try topping it off with a little refrigerant, and if that doesn't work, take it to a mechanic because it could be clogged and they can drain it and add new fluid.

As I'm working on my car's air conditioning system, I have to admit that sometimes I use the car as a sauna. But hey, being a science guy is all about exploring new ideas and pushing boundaries!

So, if you want to learn more about air conditioning or need help with your own system, be sure to check out our videos and subscribe to Donut for more cool content! You can also follow us on Twitter or Instagram at donutmedia, and I'll see you in the next video!

WEBVTTKind: captionsLanguage: en- You get into your car on a hot dayand ooh, hot, ooh, hot it's too hot.It's too spicy.You need to cool off.You better crank up that A/C.(upbeat music)That's right, ladies and gentlemen.Today, we're talking about oneof the top five inventions of all time,right up there with computers,vaccinations, pinatas,and pinatas filled with computers,vaccinations, and smaller pinatas.A/C.And no, I'm not talking about AC adaptersor Lakers legend AC Greenor Bayside High Schoolheartthrob AC Slater.No, I am talking, of course,about air conditioners.And more specifically, yourcar's air conditioning system.Bazinga.When most people hearme say air conditionerthey think I'm talkingabout hair conditionerbecause I talk so quietlyand my hair looks so good.(angelic choral music)But, actually, I'm referring tothe thing in my car that keeps me cool.No, not my sweet sunglasses.My A/C.Alright, a lot of people assume thatthe air conditioners incars are relatively new.And, well, we know whatthey say about assuming.Usually it turns out you're right.But in this case, you're wrong.Refrigerants have been around for a while.Refrigerators from thelate 1800s till 1929used the toxic gasesammonia, methyl chloride,and sulphur dioxide as refrigerants.But if they leak, you'd die.Charles Franklin Kettering,the guy who invented the firstelectric automobile emissions systemwas also the Vice President of theGeneral Motors ResearchCorporation from 1920 to 1948.He chose Thomas Midgley to head researchinto new refrigerantsthat wouldn't kill you.Well, at least not faster thandeteriorating in ozone layer.So in 1928, Midgley and Ketteringinvented a miracle compound called freon.Frigidaire received thefirst patent for the formulafor chlorofluorocarbons, orCFCs, on December 31st 1928.1930, General Motors in Dupont formedthe Kinetic ChemicalCompany that produced freonand by 1935, Frigidaireand its competitorssold eight million new refrigeratorsin the United States using freon.By 1939, the same year thatWorld War II was inventedwe got automotive A/C.Air conditioning caught on pretty quick.It was like somebody invented a wayto stay cool in anuncomfortably hot vehicle.- Air (stutters) conditioner.- And now everybody wanted it.Over half of the new cars soldcame with built in A/C by 1969.Nice.Today, we use HCFCs, orhydro chlorofluorocarbonsbecause they don't screwwith the environment as much.CFCs and HCFCs are used 'cause they gofrom liquid to gas and back very easily.The basic functions of yourvehicle's air conditioneris to cool, remove humidity,and to allow you appreciate life.The three main parts ofthe air conditioning systemare the compressor, thecondenser, and the evaporator.The A/C system is anearly closed loop systemwith a high pressure sideand a low pressure side.Man, all this talk about pressurereminds me of my favorite Queen songthat I like to listen towhen I'm under pressure.Bohemian Rhapsody.This is just a normal can ofcompressed air and right now,(scanner beeps)it's at about 73-ish degrees Fahrenheit.I'm gonna let it discharge.(can hisses)(scanner beeps)Holy mackerel, it's down to 48, 41.38.If you Europeans don't know,32 is the temperature at whichwater freezes in America.It's still cooling off.Ha-ah.It's pretty cold.This is beeping so much'cause the temperature's still changing.It's fluctuating.We're into the low teens.It's freezing.Before we depressed this canister,everything inside was a liquid.When we let it shoot outit quickly expanded and turned into a gas.That got rid of all of that energyand we can measure it by a temperature.It's kinda what your car's A/C does.High pressure is high energy.Allowing the gas to expandallows it to get rid of that energy.So we're not really blowingcold air into a car,we're taking the heat out of it.Basically, your car's airconditioning is a heat exchangermoving the heat from the insideof your car to the outside.But you'll see this aswe go through the system.The high pressure side'sclosest to the engine.Why, you ask?I don't know.What do I look like, a part doctor?In the high pressure systemwe've got a compressor.This piece runs off a beltattached to the engine.That belt turns the pistonsinside the compressor's casing.Refrigerant is drawn into the compressorin a low pressure gaseous form,put under pressure, and then is pumped outas a pressurized gas to the condenser.Man, I hate it when Ihave pressurized gas.It's why I had to stopeating all those spicy foods.The condenser's basically a radiatorand it serves the same purposeas the one in your car:To radiate heat out of the system.Also, it sits right behind the radiator.But don't call it aradiator, it hates that.Now, let's get to know it better.The process of pressurizing the gasand moving it to thecondenser creates heat.But air flowing around thetwisting tubes of the condensercools the refrigerant downuntil it's a liquid again.Like steam cooling downcondensing back into water.But, before your hairless bodycan be cool and sweat freethe refrigerant needs tohead to the receiver drierand be prepped for the evaporator.As the liquid moves out of the condenserit goes through a littlereservoir installed in the line.And this receiver driercontains desiccants,small granules that attract water.There's little packets of desiccantsin the shoe boxes or bags of beef jerkyand they do the same thing,attract water from theair to keep things fresh.And the receiver drier desiccantsremove any water that's entered the systemso that ice crystalsdon't form and damage.(sighs) Here is where we makethe switch to the low pressure side.That's exciting.I haven't been this excitedsince that time I wastalking about the high pressureside of air conditioners.I remember like it wasthree sentences ago.High pressure is high energy.Make sure that you subscribe.If you touch this part of the systemyou can feel that it'sturned from hot to cold.The high pressure liquid refrigerantflows from the receiver drierthrough the thermal expansion valvewhere it's allowed to expand.The expansion reduces thepressure on the refrigerantso it can move into the evaporator.The valve sense pressureand regulates the flow of refrigerantallowing the system to operate steadily.Moving parts of this valve can wear outand sometimes they need to be replaced.Some vehicles got a thing calledan orifice tube insteadof an expansion valve.But it serves the same purpose.They both allow the refrigerant to expandand the pressure to be loweredbefore the liquid enters the evaporator.The orifice tube allows the refrigerantto flow at a constant rateand has no moving partsbut it can become cloggedwhich is the opposite of my orifice tubewhen I eat that spicy food.Next, we travel to the magicalland of the evaporator.The evaporator's kind of likethat spray can that gets cold.And the expansion valve or orifice tubeis basically the smallhole in the air can.This is the one part of the systemthat's usually in the passenger cabinriding with ya instead of by the engine.It also looks like aradiator but it's not.Do not let it hear you say that.It absorbs the heat from the cabin.Refrigerant enters the evaporator coilas a cold, low pressure liquidand the heat from the cabinturns it back to a gas.The gas moves out of the evaporatorand out of the passengercompartment of the car,taking the heat with it.The fan pulls air fromthe passenger compartmentand the coils take the heat out of it.That air then gets pushed throughand blows in your face and cools you off.(angelic music)The refrigerant in gas formthen enters the compressorwhere it's pressurizedand the whole processstarts all over again.The system uses one ofthose sexy orifice tubesthere's an accumulator betweenthe evaporator and the compressorthat traps any excess liquidbefore it can get into the compressor.Remember, so it doesn'tturn into ice cyrstals?Guys, stay with me.The evaporator also takes the humidityout of the air in the carand that helps you feel cooland keeps you from getting moist.Water in the air condenseson the evaporator coilalong with dirt and pollenand anything else floatingaround in the cabin.So, when you stop the carand see water drippingunderneath, it's not peeing,it's probably just waterfrom the A/C evaporatorand you don't have to worry about it.But, if you're concerned that it's oilor blood or something,just give it a taste.Don't do that.But I've done that.It's like, oh, it's just water.'Cause sometimes you're like,uh, er, it's brake fluid, er.What gave it away?The fact that it was redand thick, you idiot?Why'd you taste that?(clears throat) Okay, so let'sreview what just happened.We took the refrigerantand pressurized it,which heated it up.Then we passed it acrossso that it cooled offso that the air could takesome of the heat out of it.Then, we let it expand.When it expands, it's nowcooler than when it started.That cool air passes through the cabinwhere it absorbs the heat from itand gets passed to the outsidewhere it's pressurized, heatedup, so it can be cooled.Make sense?It's really cool.(laughs) It's really cool.That's funny.'Cause it's about cool air.But just like a parent's love for a child,refrigerant doesn't last forever.If you want you car's A/C to always belike every car someone'strying to sell on Craigslistand that is, blows cold,well, you're probably gonnahave to add some refrigerant.A/C blows cold, gimme a break.That's how you're selling me this car?The A/C blows cold?I need to get to work.Okay, I'd like to add some refrigerantto my air conditioning system.So while we're talking about it,why don't we just demonstratehow to recharge your A/C?Come on.Hey.- Hey man, what are you doing this week?- Actually, we're doing air conditioning.I was hoping I could grabone of those recharge kits.- Absolutely.Alright, there you go.- Thanks dude.- Hey, you need any help we got a tonof technicians thatknow what they're doing.- (laughs) Yeah, I'm a scienceguy, I think I got this.- Okay.(downcast music)- Is it here?(downcast buzzing)Here?(happily dinging)Ah, okay.(silly whirring)So if you notice theA/C's blowing a little hotyou can try topping it offwith a little refrigerant.And if that doesn't worktake it to a mechanic'cause it could be cloggedand there might be debris.And they can drain itand they add new fluid.Sounds like my initiationto Skull and Bones at Yale.Air Conditioning.Subscribe to Donut.Click on this little yellow thing'cause it's a subscribe button.You can click downthere and ring the bell.Bing bong bing.We got lots of cool videos.Check out this one or this one.If it's the holiday season,why don't you get a lovedone some Donut merch?Shop.donut.mediaFollow us on Twitter orInstagram at donutmedia.Follow me at bidsbarto.Don't tell my wife that Isometimes use the car as a sauna.(rhythmic drumming)