I've been struggling for quite some time with what thermodynamics, cooling machine is all about. Thank you for providing such valuable different perspective. Love you work man, bravo!
Thanks for your kind words! I've added a comment at 3:45 explaining that it's not quite vertical and linking to an explanation of how crazy steep adiabats actually are. Thanks for watching, yo.
thank you this is really helpful! I finally made the connection between taking energy out of the cold reservoir via work, and dumping it to maintain a Tc in the fridge. you made it clear! :)
In a real life application of the heat pump, what temperature do we consider as that of the hot reservoir TH. In a heat pump for example, lets say we circulate water at 298K in the hot side(condenser of heat pump) which heats it up to 333K for home use. I guess Tc in this case would be the outside temperature, but which temperature in this case should we consider as TH?
Would a refrigerator as a heat engine, where the refrigerator uses a gas (refrigerant) that circulates around a loop with an expander and a compressor, be considered a open or closed system? I'm having issues determining whether it is open or closed because I don't know if mass transfer is involved with the use of a gas.
it's closed system because the gas inside the fridge doesn't disappear. it circulates . the compressor and evaporator do the job of heating and cooling the gas.
Great work homie, but I'd like to point out that @2:30 you wrote [1 - (Tc/Th)] as the simplified expression for efficiency of 'any' heat engine. This ONLY applies to the Carnot cycle and hence it would be the maximum achievable efficiency by an engine. Unless I'm tripping out haha
Thanks! I had heard it was the efficiency of any reversible heat engine. However, I'm not an expert on the idea of reversibility. Is there a reversible engine that does not follow Carnot? I'll certainly agree that it is the ideal efficiency, so perhaps an inequality would be better suited.
Considered your question about efficiency being more dependent on cold or hot reservoir: Mathematically, it looks like both have an equal effect on the efficiency but you mentioned that according the the 3rd law, it becomes nearly impossible to be 'OK' therefore I want to say that the temp of the cold reservoir has a bigger effect on the efficiency since, in chemistry terms, the cold reservoir would be the "limiting reactant". Though please correct me if I'm wrong.
But then I guess I could also say that because we have more control over the hot reservoir than the cold reservoir, then the hot reservoir has a larger effect on the efficiency since we can affect it more. Too bad I can't just talk to engines. That'd make this a lot easier.
Why can't one create a heat pump that attaches to a stirling engine that runs the heat pump? With enough temp delta, it'd work. Wonder what the maths behind that is.
For refrigerator and AC, can someone explain to me why when we want cold temperature but its leaving from cold to hot with work put in. I thought we want hot to cold. I don't understand what's our desired state I guess. Thanks
Connect an engine and a heat pump in parallel, then explain the performance of the system. The part of the work which was obtained by the engine is used for the heat pump. The temperatures of hot and cold reservoirs are maintained constant. Then think of the second law.
So Qh = Qc + W This makes all the energy neatly accounted for right? What if your Cold Res. and Hot Res were 100 lb blocks of granite and they both started out at room temp. You plugged in your fridge and ran it until Qh - Qc = 50F and then unplugged the fridge. You could let them sit until they re-assumed room temp or you could connect a small peltier device between them and produce a small amount of electricity, for a little while as their temps equalized. The power produced would fade away. The act of doing that would cause the two blocks to equalize faster. The amount of power is very small. But where did this secondary power come from?
It means the process is done slowly and with the ability to move the engine the other direction in the cycle on the PV diagram at any time. It is the maximally efficient way to go!
Hahah this is coolest physics lesson ever, you're funny but damn helped so much! Really useful! Though I'm a little confused at why the vertical line you draw at 3:45 is an adiabatic process, I thought because there is no change in volume then it is just iso-volumetric, therefore no work being done, not an adiabatic process where there is no heat transfer. Well anyway this video was very informative!
Study, for instance, a full Carnot cycle on a PV diagram. I don't go into that depth yet. For my intro class, I just need my students to see conservation of energy for these engines.
So if its 330K outside, the longer the AC is on (assuming that its consistently transferring heat from inside the house), it could be infinity efficient? All my knowledge is from a couple his videos.
Doc Schuster I didn't really have a efficiency formula on my mind, all my physics knowledge on this topic came from this video. The previous knowledge is Physics 10 (v-t, d-t graphs, acceleration & gravity.) I was just curious, as I'm going to take Power Engineering in grade 11, and Thermodynamics was one the main topics covered so I thought I would get a head start on it, Thanks.
I have question ! , we know that energy within the universe is constant (conserved) according to the first law. The second law says entropy is increasing ! but how come? why energy in the universe shouldn't increase with the increasing of entropy ?
why is COP greater than one?? how is it possible to get more output that input, heat always flows from hot to cool, but here we want it to go from cool to hot, so definitely large amount of work has to be done, please some one explain me how does one gets more output that input, disobeying the first law of thermodynics
I think it depends on type of engine, whether you are taking heat out of the engine or taking in. For instance in combustion engines(ie, Diesel and petrol engines of Cars) Qh(heat of hotter environment) is Q(in) & in refrigerator Qh is Q(out) and Qc(heat of colder system) is Q(in). Consider the two common kinds of heat flow. 1) heat flow from hot reservoir toward the cold reservoir, here Qh=Qin & Qc=Qout, (it means that an amount of heat comes from system with higher temperature, do work on the engine and expel an amount of heat to cold reservoir; maybe to water in cylinder or toward Exhaust). 2) In heat flow from cold reservoir toward hot reservoir, as in refrigerator; Qc= Qin and Qh=Qout (it means that,due to the mechanism of the engine, an amount of heat is flew from colder environment toward the engine, do work on engine and expels extra heat to the environment with higher temperature).
Qc is the output here and the input is W as we know Efficiency=output/input and here we get COP(which is used to evaluate the efficiency of the refrigerator)=Qc/W so here Qc is considered as the output
![[TH] 2024 PMSL SEA W2D4 | Summer | โอกาสสุดท้าย ของสัปดาห์สอง](http://i.ytimg.com/vi/aswciGrYovo/mqdefault.jpg)
1:51 beast mode throat clearing
HAHAAHAHAAHAHAH LOL
Lmao
N
Listen to at 1.5 speed. It's hilarious.
1:51 when u open the exam paper and see the first question
"excuse me.."
"AUHUHGHUHUMM"
"..usable heat"
I like the way you teach. You keep things real and get to the point while explaining it really well. Also good at not being boring! thanks.
You are amazing. I study chemical engineering at Cambridge, and you could probably teach all of my professors a little something about teaching style.
Savage
Whoa !
As a chemical engineering student seeing your comment 7 years later, I hope you graduated!
@@lamaa.3232 did indeed ;)
I've been struggling for quite some time with what thermodynamics, cooling machine is all about. Thank you for providing such valuable different perspective. Love you work man, bravo!
Oh, you're just getting started! You're going to LOVE physics!
1:52 Just had to shoot a horse quick.
Props for continuing to learn as you age. May all the kids be as wise as you someday! Thanks for your support, too.
a year of my thermodynamic all came in here lol. So NEAT and CLEAR. Thank youuu!!!
You are really good at making people understand the basics ;). Thank you!
Thank you so much for these videos... you saved me from failing in Thermodynamic
you the man. just came across your lectures.
simple and easy to understand. thanks bru
Commendable passion for the subject. Much respect, sir.
Could you do for Carnot Cycle and Rankine Cycle? That will be so appreciated. Thank you.
You are one of the best teachers I have ever had. And I'm old.
Thanks so much. Learning IS fun : )
I so love your lecture. I have to struggle with myself to not play the video all over again.
Thank you, Scarlett! You're very kind.
You're like the physics version of PatrickJMT
***** That guy is really great. I'll do my best to live up to that truly kind compliment!
Doc Schuster Just be who you are... your'e GRRRRR...R^∞^∞^∞^...^(∞)...∞... EAT
I knew there was something familiar about him haha
i recommend michel van biezen, a very underrated physics prof. but sadly he doesn't cover this topic yet :)
and im grateful for this guy :)
SUPERB! Using this to cover the final part of A Level Physics with my Year 13s while I am off with Covid. Thanks!!!
Wow. Your praise is super kind. Thank you. I hope you rock that MCAT and become a great doctor. Go improve the world!
I wish I have you as my lecturer or tutor. That will be cool!
Thanks for your kind words! I've added a comment at 3:45 explaining that it's not quite vertical and linking to an explanation of how crazy steep adiabats actually are. Thanks for watching, yo.
I'm using these videos to study for the MCAT too! Very helpful, I agree!
u have cleared concept very easily by differentiating them...
thanks..
I like you. Not because you sound like Ashton Kutcher, but because you're funny.
thank u man .... u made me learn my lesson even after not attending the classes.... u r really good at teaching.... :-)
Me too ☺️🎺😁😎
I'm so glad to hear it! I hope you become a super doctor and cure all kinds of people. We need you.
When you sat through a two and a half hour movie and finally leave the theater 1:51
I have a thermodynamics exam tomorrow. Why didn't I came across this earlier??? This video is just wonderful 🤣
11:50 this part he's like when your changing gears from low to high ...LOL!
GOSH I LOVE THIS. NEVER HAD SO MUCH FUN IN PHYSICS
thanks for these videos doc! They really are helpful :-)
thank you this is really helpful! I finally made the connection between taking energy out of the cold reservoir via work, and dumping it to maintain a Tc in the fridge. you made it clear! :)
lol right
yup
You are absolutely amazing.
YO HOUSE :''D you made my day..thanks!
This professor is awesome!
Excellent Video ! very very helpful
12:00 best fridge salesman the world has ever seen
Amazing 😍
And easy to understand thank you sir
As one of the slackers, I like your style.
Cool stuff, and very helpful. Two thumbs up.
Thank you so much !!! Was very helpful indeed :-)
the best explanation
Dude you're amazing !
you are the best. thanks for the video :)
My dude you’re amazing
Awesome video, thanks.
Wow... well explained.. perfect..
Shout out to @OfficialJimmyKloke a well rounded individual
In a real life application of the heat pump, what temperature do we consider as that of the hot reservoir TH. In a heat pump for example, lets say we circulate water at 298K in the hot side(condenser of heat pump) which heats it up to 333K for home use.
I guess Tc in this case would be the outside temperature, but which temperature in this case should we consider as TH?
Thanks for this video 📹
?But how heat move to the refigerator from the cold reservoir
Is there any sort of resistor in between? i
Job well done.
great and interesting video
WashU should hire you as our professor tbh
tqvm master!
ultimate ...keep it up
cool and interesting explanation..
at 8:00 you are talking about the universe barrier, the one who are able to travel into the other stars will going to vanished first
Would a refrigerator as a heat engine, where the refrigerator uses a gas (refrigerant) that circulates around a loop with an expander and a compressor, be considered a open or closed system? I'm having issues determining whether it is open or closed because I don't know if mass transfer is involved with the use of a gas.
it's closed system because the gas inside the fridge doesn't disappear. it circulates . the compressor and evaporator do the job of heating and cooling the gas.
Great work homie, but I'd like to point out that @2:30 you wrote [1 - (Tc/Th)] as the simplified expression for efficiency of 'any' heat engine. This ONLY applies to the Carnot cycle and hence it would be the maximum achievable efficiency by an engine. Unless I'm tripping out haha
Thanks! I had heard it was the efficiency of any reversible heat engine. However, I'm not an expert on the idea of reversibility. Is there a reversible engine that does not follow Carnot?
I'll certainly agree that it is the ideal efficiency, so perhaps an inequality would be better suited.
Considered your question about efficiency being more dependent on cold or hot reservoir:
Mathematically, it looks like both have an equal effect on the efficiency but you mentioned that according the the 3rd law, it becomes nearly impossible to be 'OK' therefore I want to say that the temp of the cold reservoir has a bigger effect on the efficiency since, in chemistry terms, the cold reservoir would be the "limiting reactant".
Though please correct me if I'm wrong.
But then I guess I could also say that because we have more control over the hot reservoir than the cold reservoir, then the hot reservoir has a larger effect on the efficiency since we can affect it more.
Too bad I can't just talk to engines. That'd make this a lot easier.
Ha! Talking to engines!
My point is the mathematical observation of numerator vs. denominator. But I like both your observations.
Why can't one create a heat pump that attaches to a stirling engine that runs the heat pump?
With enough temp delta, it'd work. Wonder what the maths behind that is.
For refrigerator and AC, can someone explain to me why when we want cold temperature but its leaving from cold to hot with work put in. I thought we want hot to cold. I don't understand what's our desired state I guess. Thanks
Connect an engine and a heat pump in parallel, then explain the performance of the system. The part of the work which was obtained by the engine is used for the heat pump. The temperatures of hot and cold reservoirs are maintained constant. Then think of the second law.
brilliant
thank you soooooo much
Thank you :D
Thanks so much
I like how you start yelling when you talk about the CoP
So Qh = Qc + W This makes all the energy neatly accounted for right?
What if your Cold Res. and Hot Res were 100 lb blocks of granite and they both started out at room temp. You plugged in your fridge and ran it until Qh - Qc = 50F and then unplugged the fridge.
You could let them sit until they re-assumed room temp or you could connect a small peltier device between them and produce a small amount of electricity, for a little while as their temps equalized. The power produced would fade away. The act of doing that would cause the two blocks to equalize faster. The amount of power is very small.
But where did this secondary power come from?
You are pretty good
thanx
It's very useful and I'm laughing my ass off.
you’re amazing
Why do we have the word reversible with various processes in carnot engine?
what does that reversible stand for?what does it mean?
plzzz explain.
It means the process is done slowly and with the ability to move the engine the other direction in the cycle on the PV diagram at any time. It is the maximally efficient way to go!
Thanks a lot!
Hahah this is coolest physics lesson ever, you're funny but damn helped so much! Really useful! Though I'm a little confused at why the vertical line you draw at 3:45 is an adiabatic process, I thought because there is no change in volume then it is just iso-volumetric, therefore no work being done, not an adiabatic process where there is no heat transfer. Well anyway this video was very informative!
I didn't get it from 11:58 to 12:11 ... Can you explain that?
thx doc
Best teacher ever ROFL...my mom asked me if i was watching pewdiepie again hahaha
did you actually roll on the floor?
LOL
Can you explain mathematically how adding work allows us to move heat energy from cold reservoir to hot reservoir?
Study, for instance, a full Carnot cycle on a PV diagram. I don't go into that depth yet. For my intro class, I just need my students to see conservation of energy for these engines.
the cop=Qc/W. Like wht ayou mention cop=5, then 5=Qc/W. Does that mean 5W=Qc which mean more work need to be done to extract the heat Qc out?
can't even hypothesize stealing heat without COPs invading the paper
So if its 330K outside, the longer the AC is on (assuming that its consistently transferring heat from inside the house), it could be infinity efficient?
All my knowledge is from a couple his videos.
KingCodeTV What equation for efficiency is on your mind? Time shouldn't have an effect (except for complicated things like duty-cycles).
Doc Schuster I didn't really have a efficiency formula on my mind, all my physics knowledge on this topic came from this video. The previous knowledge is Physics 10 (v-t, d-t graphs, acceleration & gravity.)
I was just curious, as I'm going to take Power Engineering in grade 11, and Thermodynamics was one the main topics covered so I thought I would get a head start on it,
Thanks.
haven't you got it a little wrong?
The 1-Th/Tc is the carnot/max possible efficiency, and the 1-Qc/Qh and Wout/Qh is the actual efficiency?
I have question ! , we know that energy within the universe is constant (conserved) according to the first law. The second law says entropy is increasing ! but how come? why energy in the universe shouldn't increase with the increasing of entropy ?
this is totally awesome thanks a lot
thank u ♡
like the way - you say "sucker"
i enjoying this
you are awesome
but would you say it "it is carnot" when you replace Q with T
mansour nasr yeah the replacement only applies to carnot cycle with the thermodynamic temp scale
why is COP greater than one?? how is it possible to get more output that input, heat always flows from hot to cool, but here we want it to go from cool to hot, so definitely large amount of work has to be done, please some one explain me how does one gets more output that input, disobeying the first law of thermodynics
omg thanks for nice expanation!!!
I still don't get how CoP can be greater than 1? Someone please explain this to me.
Confused! for this instead of using Qh and Qc if we used Q(in) and Q(out) which would be which?? so does Qh = Q(in) or Q(out) etc??? PLEASE HELP!
Qh is Q(out) and Qc is Q(in)
I think it depends on type of engine, whether you are taking heat out of the engine or taking in. For instance in combustion engines(ie, Diesel and petrol engines of Cars) Qh(heat of hotter environment) is Q(in) & in refrigerator Qh is Q(out) and Qc(heat of colder system) is Q(in).
Consider the two common kinds of heat flow.
1) heat flow from hot reservoir toward the cold reservoir, here Qh=Qin & Qc=Qout, (it means that an amount of heat comes from system with higher temperature, do work on the engine and expel an amount of heat to cold reservoir; maybe to water in cylinder or toward Exhaust).
2) In heat flow from cold reservoir toward hot reservoir, as in refrigerator; Qc= Qin and Qh=Qout (it means that,due to the mechanism of the engine, an amount of heat is flew from colder environment toward the engine, do work on engine and expels extra heat to the environment with higher temperature).
Qc is the output here and the input is W
as we know Efficiency=output/input and here we get COP(which is used to evaluate the efficiency of the refrigerator)=Qc/W so here Qc is considered as the output
U r da best✌
can I emphasize that for you..." YOU CAN TAKE MORE ENERGY OF YOUR COLD..." DAMN haha
Why are there no equations like "THe Ideal gas Law" or the mcDeltaT ?
You found one of my purely conceptual videos! If it's equations you want, I've got plenty more videos. Check my website full of links.