How the heck does A/C actually cool air? | SCIENCE GARAGE

How the heck does A/C actually cool air? | SCIENCE GARAGE


– You get into your car on a hot day and 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 one of 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 adapters or Lakers legend AC Green or Bayside High School
heartthrob AC Slater. No, I am talking, of course,
about air conditioners. And more specifically, your
car’s air conditioning system. Bazinga. When most people hear
me say air conditioner they think I’m talking
about hair conditioner because I talk so quietly
and my hair looks so good. (angelic choral music) But, actually, I’m referring to the thing in my car that keeps me cool. No, not my sweet sunglasses. My A/C. Alright, a lot of people assume that the air conditioners in
cars are relatively new. And, well, we know what
they 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 the
late 1800s till 1929 used the toxic gases
ammonia, methyl chloride, and sulphur dioxide as refrigerants. But if they leak, you’d die. Charles Franklin Kettering, the guy who invented the first electric automobile emissions system was also the Vice President of the General Motors Research
Corporation from 1920 to 1948. He chose Thomas Midgley to head research into new refrigerants
that wouldn’t kill you. Well, at least not faster than
deteriorating in ozone layer. So in 1928, Midgley and Kettering invented a miracle compound called freon. Frigidaire received the
first patent for the formula for chlorofluorocarbons, or
CFCs, on December 31st 1928. 1930, General Motors in Dupont formed the Kinetic Chemical
Company that produced freon and by 1935, Frigidaire
and its competitors sold eight million new refrigerators in the United States using freon. By 1939, the same year that
World War II was invented we got automotive A/C. Air conditioning caught on pretty quick. It was like somebody invented a way to stay cool in an
uncomfortably hot vehicle. – Air (stutters) conditioner. – And now everybody wanted it. Over half of the new cars sold came with built in A/C by 1969. Nice. Today, we use HCFCs, or
hydro chlorofluorocarbons because they don’t screw
with the environment as much. CFCs and HCFCs are used ’cause they go from liquid to gas and back very easily. The basic functions of your
vehicle’s air conditioner is to cool, remove humidity, and to allow you appreciate life. The three main parts of
the air conditioning system are the compressor, the
condenser, and the evaporator. The A/C system is a
nearly closed loop system with a high pressure side
and a low pressure side. Man, all this talk about pressure reminds me of my favorite Queen song that I like to listen to
when I’m under pressure. Bohemian Rhapsody. This is just a normal can of
compressed 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 which
water 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 out it quickly expanded and turned into a gas. That got rid of all of that energy and 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 expand allows it to get rid of that energy. So we’re not really blowing
cold air into a car, we’re taking the heat out of it. Basically, your car’s air
conditioning is a heat exchanger moving the heat from the inside
of your car to the outside. But you’ll see this as
we go through the system. The high pressure side’s
closest to the engine. Why, you ask? I don’t know. What do I look like, a part doctor? In the high pressure system
we’ve got a compressor. This piece runs off a belt
attached to the engine. That belt turns the pistons inside the compressor’s casing. Refrigerant is drawn into the compressor in a low pressure gaseous form, put under pressure, and then is pumped out as a pressurized gas to the condenser. Man, I hate it when I
have pressurized gas. It’s why I had to stop
eating all those spicy foods. The condenser’s basically a radiator and it serves the same purpose
as the one in your car: To radiate heat out of the system. Also, it sits right behind the radiator. But don’t call it a
radiator, it hates that. Now, let’s get to know it better. The process of pressurizing the gas and moving it to the
condenser creates heat. But air flowing around the
twisting tubes of the condenser cools the refrigerant down
until it’s a liquid again. Like steam cooling down
condensing back into water. But, before your hairless body
can be cool and sweat free the refrigerant needs to
head to the receiver drier and be prepped for the evaporator. As the liquid moves out of the condenser it goes through a little
reservoir installed in the line. And this receiver drier
contains desiccants, small granules that attract water. There’s little packets of desiccants in the shoe boxes or bags of beef jerky and they do the same thing, attract water from the
air to keep things fresh. And the receiver drier desiccants remove any water that’s entered the system so that ice crystals
don’t form and damage. (sighs) Here is where we make the switch to the low pressure side. That’s exciting. I haven’t been this excited
since that time I was talking about the high pressure
side of air conditioners. I remember like it was
three sentences ago. High pressure is high energy. Make sure that you subscribe. If you touch this part of the system you can feel that it’s
turned from hot to cold. The high pressure liquid refrigerant flows from the receiver drier through the thermal expansion valve where it’s allowed to expand. The expansion reduces the
pressure on the refrigerant so it can move into the evaporator. The valve sense pressure and regulates the flow of refrigerant allowing the system to operate steadily. Moving parts of this valve can wear out and sometimes they need to be replaced. Some vehicles got a thing called an orifice tube instead
of an expansion valve. But it serves the same purpose. They both allow the refrigerant to expand and the pressure to be lowered before the liquid enters the evaporator. The orifice tube allows the refrigerant to flow at a constant rate
and has no moving parts but it can become clogged which is the opposite of my orifice tube when I eat that spicy food. Next, we travel to the magical
land of the evaporator. The evaporator’s kind of like
that spray can that gets cold. And the expansion valve or orifice tube is basically the small
hole in the air can. This is the one part of the system that’s usually in the passenger cabin riding with ya instead of by the engine. It also looks like a
radiator but it’s not. Do not let it hear you say that. It absorbs the heat from the cabin. Refrigerant enters the evaporator coil as a cold, low pressure liquid and the heat from the cabin
turns it back to a gas. The gas moves out of the evaporator and out of the passenger
compartment of the car, taking the heat with it. The fan pulls air from
the passenger compartment and the coils take the heat out of it. That air then gets pushed through and blows in your face and cools you off. (angelic music) The refrigerant in gas form
then enters the compressor where it’s pressurized
and the whole process starts all over again. The system uses one of
those sexy orifice tubes there’s an accumulator between the evaporator and the compressor that traps any excess liquid before it can get into the compressor. Remember, so it doesn’t
turn into ice cyrstals? Guys, stay with me. The evaporator also takes the humidity out of the air in the car and that helps you feel cool and keeps you from getting moist. Water in the air condenses
on the evaporator coil along with dirt and pollen and anything else floating
around in the cabin. So, when you stop the car and see water dripping
underneath, it’s not peeing, it’s probably just water
from the A/C evaporator and you don’t have to worry about it. But, if you’re concerned that it’s oil or 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 red
and thick, you idiot? Why’d you taste that? (clears throat) Okay, so let’s
review what just happened. We took the refrigerant
and pressurized it, which heated it up. Then we passed it across
so that it cooled off so that the air could take
some of the heat out of it. Then, we let it expand. When it expands, it’s now
cooler than when it started. That cool air passes through the cabin where it absorbs the heat from it and gets passed to the outside where it’s pressurized, heated
up, 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 be like every car someone’s
trying to sell on Craigslist and that is, blows cold, well, you’re probably gonna
have 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 refrigerant to my air conditioning system. So while we’re talking about it, why don’t we just demonstrate
how 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 grab
one of those recharge kits. – Absolutely. Alright, there you go.
– Thanks dude. – Hey, you need any help we got a ton of technicians that
know what they’re doing. – (laughs) Yeah, I’m a science
guy, I think I got this. – Okay. (downcast music) – Is it here?
(downcast buzzing) Here?
(happily dinging) Ah, okay. (silly whirring) So if you notice the
A/C’s 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 ’cause it could be clogged
and there might be debris. And they can drain it
and they add new fluid. Sounds like my initiation
to 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 down
there 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 loved
one some Donut merch? Shop.donut.media Follow us on Twitter or
Instagram at donutmedia. Follow me at bidsbarto. Don’t tell my wife that I
sometimes use the car as a sauna. (rhythmic drumming)

100 thoughts on “How the heck does A/C actually cool air? | SCIENCE GARAGE

  1. make a video on toe, camber and caster of wheel………it would be of great information………

  2. Recharging ac doesn't work because it's a "closed looped system" and if that chit leaked out then it's going to again

  3. They did not invent freon, they developed a refrigerant. Freon was a brand name for dupont refrigerants. There was Freon 22, Freon 12, Freon 502, and a few others at that time. Do not continue to call refrigerants Freon, you are spreading misinformation.

  4. I love when other states complain about their hot cars. I live in FL and my shifter knob is metal… I lost feeling in my fingers years ago…

  5. 3:45 "europeans dont know 32 is the tempeature at which water freeze"
    WELL GUESS WHAT Fahrenheit WAS A EUROPEAN

  6. I work in a giant ammonia cooled freezer and I’m always scared to death that some dumbass will hit a pipe with a forklift 😬

  7. Well if you had the high pressure side on the AC in the cabin you would only get heat out of the thing… the engine bay would be getting the cold side.

  8. I think of the 19 cars I've 3 have had working ac
    All 3 of my current cars have ac bit dosnt work on any of them

    Thank fudge I live on the uk where it never gets particularly hot.

  9. This video had too many stupid and forced jokes. Would rather watch Patel try to explain how an A/C works in the most clumsy english known to man.

  10. You're not funny, and your side 'jokes' seriously hamper any useful information lost in your face punching cringeworthy act.

  11. 😆 I habe to do it again! Releasing pressure is not releasing heat energy! What actually happens is the pressurized contents cannot hold as much heat energy when compresed. That's why it feels hot on the condenser. Its releasing energy when compressed. Not vice versa. When it expands it can hold more heat energy and start absorbing the heat around it. Thus it feels cold! 😁

  12. Why aren’t their any more Science Garage on DonutMedia? Did he left? Or what happened? PEOPLE WANTS TO KNOW!!

  13. Thumbs down because "America" "spicy food" etc… I know your full of it but don't let it spill out your mouth

  14. I love it that he explains it like if I were mentally challenged because any other way my mental retardation will act up:3

  15. These videos are easy to understand and relaxing to watch is because its like your high ass explaining to your also high ass friend how society works

  16. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  17. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  18. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  19. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  20. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  21. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  22. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  23. mostly right but the only reason you would need to add refrigerant is because some leaked out. if your a/c is not getting cold check airflow through your evaporator and condenser before checking the state of charge. and those stupid little cans you buy at the auto parts store do not do a good job of charging and a gauge set will yield more accurate results.

  24. Has the ice wizard in a little jail cell when u turn on the AC it zaps TF out of him and he makes it cold the more you turn it up the more he is zapped

  25. @Donut Media Why we don't use Liquid Nitrogen to be stocked and sprayed at interval times to cool down the interior of the car (cabin), instead of using Refrigerant and it's process of Condenser n Evaporator???

  26. Topping it off WILL NEVER WORK for R134. You are just going to waste your money. Your car AC system requires a specific weight range of refrigerant to work. If it wears out and you just add more, you will over pressurize the system and it still wont blow cold(ok it might for a short period of time), and you might break something. The only way to do it right is to have your AC system drained into an appropriate waste container, put it under vaccuum, then refill it with the specified weight of refrigerant (and oil if needed).

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