The Basic Refrigeration Cycle

We will will help you scientifically understand how an air conditioner removes heat from a building. Warning: Some of you may get flashbacks to high school chemistry and the Ideal Gas Law (PV=nRT).

[@likele3572]

Your video is straight forward, your sketch is clear, concise and specific, and your physical demonstration of refrigeration cycle is just corresponding to the sketch! Thank you!!

[@goldwingnut1954]

Totally agree! Fiiiiinally this is beginning to soak in to my thick skull.

[@MohanKalasa]

By far the best explanation I could find on youtube. You are super crisp in your technical explanations and now I don't need to go through a lot of literature to understand phenomena behind refrigeration cycle. Kudos to your efforts !

[@jollyscaria1922]

Good

[@MrPraveenGeorge]

You explained it better than many other videos I have seen on this topic. I think all the difference was in explaining how compression reduces volume which leads to increase in temperature.

[@Fredsterrrrr]

Thank you so much for this! It really helped understand much better. Especially when you show the actual components and how it works

[@Danny-fs1hk]

He is a very good teacher. That was a quick Master Class.

[@cornpop7805]

You are talented! I have watched dozens of videos on this topic and although some did a decent job of explaining the details, none of them did as well as you! I really liked the vertical line concept, where you divided the 4 components into two categories, that's not something I've seen anywhere else. That made the difference in the concepts clicking for me.

[@FlorianBoyd]

I really learned something. Being a dummy about this i always thought when i went out to my compressor outside that the thick cold pipe was going INTO the house and the thin hot pipe was coming FROM inside. It's the opposite. Very good video. Thank you.

[@louisnicchio95]

Excellent explanation, I never could grasp the idea of why the temperature would have to get increased even more in the refrigerant, now I understand. Many thanks......

[@najeebalyafai348]

Funny you said that because Same with me couldn’t understand why refrigerant tempeture needed to be raised to get cooler, I did research other places then this video just shined a light on it

[@DanArr1]

Great basic explanation! Easy to follow and understand the cycle.

[@ciscokidd6119]

Very simple to digest and well explained. Ty for the video sir

[@fritzpierre92]

Excellent job! Straight and to the point 👍

[@josevasquez1781]

Simple explanation and straight to the point. I would like to see this him explain chilled water chiller using his simply method of communication.

[@PilotImmanueltv]

Wow best explanation I have ever got so far....I don't know why they always make simple things hard....thank you.

[@TECTubefilms]

Thanks. We are not always the smartest folks in the room, but we at least know how to speak in layman's terms to explain what little bit we do know.

[@mellis966]

Thanks for your explanation it was very clear and easy to understand.

[@DrDangerPuppy]

I've wanted to understand the basics for a very long time. Now I understand. Thank you!

[@jessicaburns6140]

This is great! Thank you! I am using this to help my CTE HS Students review!

[@hamiltonhamilton303]

Very nice explanation.

[@harrystrohm7614]

THANK YOU & LOOKING FORWARD TO MORE VIDEOS WELL MADE!

[@aritelecemian2971]

Well done sir. It's explained perfectly

[@timothybunch7143]

Excellent video, thank you!

[@musakavalci9470]

Very well explained!! 👍🏼👍🏼

[@warrior1794]

Excellent Explanation Thanks So Much

[@Persephales]

Anyone else notice the end credits song is the same one CGP Grey uses?😁 nice little Easter egg from an explainer video

[@TECTubefilms]

We do not know who CGP Grey is, but they must be selecting from the same library of free use music that our video guys does. (we may be a little frugal over here LOL)

[@KebbyLL]

Thanks a lot never had that clear explanation regarding heat transfer :D

[@kjhsia2221]

Super clear. Thanks!

[@Appicerocks]

Excellent job!

[@stephenburns3262]

Nice explanation

[@micheldufenberg4745]

Great video

[@kamalnasari8632]

Xmas . Beautiful teaching . ❤

[@Ox9707]

I definitely thought the names for "liquid line" and "suction line" were stupid and confusing before you broke it down this way. It's easier to think about the liquid line and txv being one pair in the cycle and the suction line and suction line and compressor being the other pair.

[@bhabi7071]

Excellent

[@jetjohnson1106]

This guy is an ACE

[@edwinalvarado0922]

Great video !!!!!

[@wilguyaugusma9428]

Great job

[@May-yv2kq]

thanks you make it easy to understand

[@ayadsuha]

at which point in condensing coil the Freon will start to change from vapor to liquid ..and the evaporator from liquid to vapor ? can you answer and help me please

[@TECTubefilms]

That will happen part way thru the coil, but it will depend on the specific conditions... refrigerant temps, airflow temps, and coil length.

[@victormena156]

Thank you

[@ctbt1832]

Nice video I think what would’ve made this video better is if you will explain everything inside of the condenser I see parts on the suction line that you’re just running your finger across and not explaining what they are or what they do

[@TECTubefilms]

We have another video that dives deeper into the components. Checkout kzbin.info/www/bejne/rKmoaGeNfLaLbMk&t=

[@davidngai5281]

Cc Bb 个

[@bah920]

I have a question please .. I am not native speaker so my grammar not that much good.. what is the temperature at the suction and discharge line of the throttle expansion valve TXV ? and is decreasing pressure in this valve the main reason of decreasing temperature which will be capable to absorb heat from the food inside ?

[@TECTubefilms]

This video was based on HVAC, not refrigerated food storage, but the principles are the same. Temperatures are specific to the application and the type of refrigerant used. Yes, the decrease in pressure through the TXV decreases the temperature since this is a fixed volume. PV=nRT

[@bah920]

@@TECTubefilms Thank you very much for fast replaying, I appreciate your effort

[@carultch]

@@bah920 P*V=n*R*T is only valid for ideal gasses. A refrigeration cycle expands liquid into a two state mixture, which isn't even close to an ideal gas. The process occurs as the liquid drops pressure and ends up at a pressure where it should be boiling. This causes some of the refrigerant to use the thermal energy to change its state from liquid to gas. On net, there is no heat added or removed from the system, but it drops in temperature by producing another destination for its thermal energy (i.e. the latent heat of vaporization). If you did expand an ideal gas through a valve like this, it wouldn't produce any temperature drop. Real gasses do change temperature by a small amount, and some real gasses (e.g. helium) even heat up when doing this, in an effect called the Joule-Thompson effect. But for an ideal gas, there theoretically is no temperature change, when expanding in an isenthalpic process (i.e. a frictional valve). You need a turbine or other equipment that trades thermal energy for mechanical work, in order to drop temperature as an ideal gas expands.

[@ismailahmed8031]

good work

[@nadianajesch6367]

So, would a refrigerator be a real-life application of the "ideal gas law" or "Combined gas law"?

[@TECTubefilms]

Sounds like a great question for a chemistry professor instead of simply air conditioning folks like us. LOL

[@TECTubefilms]

socratic.org/questions/how-does-the-ideal-gas-law-differ-from-the-combined-gas-law

[@carultch]

There is a refrigerator built as an application of the ideal gas law, which is called the Bell-Coleman cycle. It is the Brayton cycle (what airplanes and gas-fired power plants use) but in reverse, that uses air as a working fluid. The standard refrigeration cycle is like a Rankine cycle in reverse, while the Bell-Coleman cycle is a Brayton cycle in reverse. The essential difference is that a turbine has to replace the throttling valve, because air doesn't drop in temperature in an isenthalpic process nearly as much as refrigerant does, when expanding to a two-state mixture. So they replace the isenthalpic process with an isentropic process, and re-capture some of the backwork. With standard refrigeration cycles, the diminishing return of the turbine means that the design opts for a valve instead. A Bell-Coleman cycle isn't as common as a standard vapor-compression refrigeration cycle, because air's heat transfer properties are a lot worse than that of refrigerant, so the two heat exchangers aren't nearly as effective with air, as they are with boiling and condensing refrigerant.

[@johnjay599]

Temperature and pressure follow each other. One up, the other up. One down, the other down.

[@TECTubefilms]

That is correct. If the volume is fixed (like it is in a refrigeration circuit), then pressure and temp go up and down together. PV=nRT

[@ncbwztcw]

Why do you use the phrase "condensor rejects heat" rather than "condensor emits heat"? The light bulbs in my house don't reject light, they emit it. Also, according to the diagram, the temperature on either side of the TXV appears to be the same (the colours are the same) - in reality, there is a drop in temperature across the TXV that matches the drop in pressure.

[@TECTubefilms]

Rejecting heat is the common way to describe heat leaving the structure. Condensers, condensing units, and cooling towers are always referred to as rejecting heat. Terminal devices inside the structure are usually referred to as heat emitters, such as radiators, convectors, etc. Or at least that is the terminology used by the HVAC industry in the Midwest.

[@TECTubefilms]

Yes, true. As the pressure is lowered by the TXV the temperature is also reduced because it is a fixed volume system. PV=nRT

[@carultch]

@@TECTubefilms P*V=n*R*T is only valid for an ideal gas, which essentially means a gas that isn't anywhere close to its liquid state. The reason the expansion valve cools the refrigerant is due to the liquid refrigerant dropping pressure to a point where it should be boiling. The refrigerant trades energy of its temperature, for energy of its phase (the latent heat of vaporization), as it passes through a frictional constriction that drops pressure with no energy exchange.

[@TECTubefilms]

@@carultch Yes, you are correct that PV=nRT stops being the correct formula once we enter the liquid state. However there still exists a similar relationship of temperature and pressure for liquids. As you decrease pressure of a liquid, temperature also decreases, and vice-versa. However, because we have an incompressible liquid, the P/T relationship is not as linear as it is for a compressible gas. A large decrease in pressure only yields a small decrease in temperature.

[@SMFFL100]

Txv does not stand for thermal xv, it stands for thermostatic xv.

[@TECTubefilms]

you are correct

[@ryanhoger1]

That is the first time I have misspoke in 21 years working here. LOL Good catch SMFFL100

[@TECTubefilms]

Yes... the first time you have misspoke... the other times you were just wrong ;)

[@SMFFL100]

Really a common vocabulary error. Great video, very informative!

[@deepakbhat9664]

I have one question,how refrigerant condenses when the its boiling point itself -40 degree C. Because outdoor temp will be 30+ degree. I know that it is because of pressure, i had read it somewhere but,can anyone explain

[@TECTubefilms]

Let us offer you this 3 hour, 2-part series on heat transfer and A/C refrigeration basics. In the 2nd part, your question is answered. Part 1 tecstorage.com/controls/Webinars/2015-05-11%20ABCs%20of%20Comfort.wmv Part 2 tecstorage.com/controls/Webinars/2015-05-18%20ABCs%20of%20Comfort.wmv

[@TECTubefilms]

or just Google PV=nRT

[@rubinarana2297]

Wait what? I didn't understand how heat goes away from tight concrete wall?

[@TECTubefilms]

concrete wall?

[@tedcleveland8488]

can you explain why the small copper pipe freezing for 30 second or 1 minutes when switch on?

[@TECTubefilms]

Not sure what you are asking? Which specific pipe? What are you switching on in this example? A compressor, a condenser fan, an evaporator fan, or all 3?

[@tedcleveland8488]

@@TECTubefilms the two copper pipe line that from outdoor unit (compressor i supposes) to indoor unit pipes, one of them (the small pipe was icey when switch on..but only for 1 minutes)

[@tedcleveland8488]

@@TECTubefilms spilt air condition

[@TECTubefilms]

@@tedcleveland8488 That is not normal at all. If you had ice issues develop after running for a while, that is usually either an airflow or charge issue. Not sure why you would see ice on the lines during startup, though. For ice to form, that means the pipe itself got colder than the dewpoint of the air and caused condensation AND the pipe (or the air directly adjacent to the pipe) dropped below 32 degrees.

[@TECTubefilms]

@@birdyboyblue There could be a handful of things going wrong, and that is one possibility. This is not normal operation.

[@cecshowstars1050]

where is the sub cooling and superheat explanation? that is also part of the refrigeration cycle I have to say is a good video but I think that you just when over a basic of the basic of the really basic of the basic cycle.

[@TECTubefilms]

Well... the title of the video is "The Basic Refrigeration Cycle." LOL

[@paulinomatos259]

were the secul

[@Sc19869]

Awesome video

[@keshansalinda3141]

Thank you

[@Supernova12034]

Great video