Respected Sir...... Flash Chamber Suck the vapours ..... then after that .. where these vapours go from flash chamber ......and my 2nd question is that .... system capacity is 10 kw ..... and we get power requirement 3.19 kw ... does it mean that our system is extra efficient ...?
Hello sir i have Question about this problem, as in the problem it is not mentioned about superheating of refrigerant (the refrigerant leaves the evaporator as saturated vapor i.e it should be h1=h1 dash) then why we consider the superheating while solving problem .
"The refrigerant leaves the evaporator as saturated vapor": By this term, I thought the refrigerant goes to the compression at the saturated vapor condition. But the explanation shows the refrigerant superheated to point 1. I understand the degree of superheating equals the degree of subcooling. But the question explicitly says "saturated vapor". Would you please help me to understand why this term is used in the question?
Please take note that we are dealing with enthalpy and temp is only a function of enthalpy; it is the enthalpy (or ENERGY that is equal not the temp change it self)
Hello Rohit, Your video was great but i would appreciate some clarification on two issues. 1. At 16:00 I am missing how h1 was arrived upon. 2. At 19:56 the reason for the introduction of natural log (ln). Sorry but I have been out of college for thirty years, HaHa . Thanking you in advance, Joseph
gearhead0800 for #1 he used algebra... By theory: deg of subcooling = deg of superheat deg of subcooling = m(h3’-h3) deg of superheat = m(h1-h1’) m(h1-h1’) = m(h3’-h3); m is constant, it cancels h1-h1’ = h3’-h3; substitute the values; find h1
For #2 reviewing isentropic process; cpln(T2/T1) is the derived formula in getting the change in entropy (s value) Note that for isentropic process s1=s2 since entropy is constant; from TS Diagram and by algebra you can expand s1=s2 (expanded formula is the equation with ln) we expand for you to get T2 that you need for h2...
sir, it was given in the question that the refrigerant leaves the evaporator as saturated vapour.... then why did you show it as super saturated at point 1 in the diagrams?... also please explain that in the question only Cpg is given... then why did you take Cpg to fing h3 of condenser outlet... where the refrigerant must be in liquid form.. so we need Cpw.. right?
See try to understand , no doubt that from evaporator saturated vapour is coming out.. but I have extended the the horizontal line from saturated vapour line to point no. 1 because in that portion the saturated vapour has further passed through a heat exchanger for superheating purpose
Evaporator works only in the portion 4 to 1'(saturated vapour line). From 1' to point 1 ,refrigerant is passing through heat exchanger for the purpose of superheating. I think now it is clear to you. Thank you
@@RohitChowdhury_sajaysaini If I consider no superheating, is it acceptable? Since the question says "the refrigerant leaves the evaporator as a saturated vapor." I assumed no superheating.
hello sir its great to watch the video but i have an issue regarding the calculation of h1 its 411.92 not 415.6 and based on that further calculation are also mistaken like the value of t1= -6 . thank you///
Actually sir had taken Cp liquid equals to Cp of vapour. which was a mistake. Cp of liquid is not given in question. Atleast we don't know what is Cp of liuid. If you get Cp of liquid automatically all your values with match with sir's valve. since sir wrote them from book directly without any calculations. so they are correct. watch video one more time from 12.35 for better understanding.
thank you very much, sir, this video is very helpful and I was so confused all along after watching this video everything is now understandable. Sir my question is that why is your T2 in degrees Celcius after converting other temperatures into Kelvin?
Because the system has what you called LIQUID-SUCTION VAPOUR HEAT EXCHANGER, which is stated in the question, meaning Subcooling and Superheating is present; that is why he mentioned that degree of subcooling is equal to deg of superheat...extending the process point to subcooled area indicates subcooling and extending the process point to superheated area is superheating
Thank you so much sir........ I hav one doubt,in question it is given that refrigerant leaves the evaporator as a saturated vapour then why are we superheating it from 1 to 1'?
Saurav Kumar we do not superheat it... mechanical system are never ideal....so superheating is a process we cannot control....it happens even if we dont want it to be...
From the concepts of second law, we can say that ds=dQ/T(for int. Rev. Processes) . Now on integration of both sides you will get your final answer as s2-s1= m cp ln(t2/t1) We have substituted Q = m cp dt( const. Pressure)
Sir your video is very nice but there is a lots of calculation misktakes. At 16:01 the value of h1 is entirely different from what you have calculated. It takes me a lot of hours to understand... But at the end the answer are the same and I m happy with that😀 Sir my request to you please keep the calculation right. And we are waiting for more videos from RAC subject.
can i ask if the problem says R134A has a zero degree fahrenheit subcooling? does it mean the condenser pressure and zero degree subcooling meet at the liquid saturation line? thank you so much for this video
sir to finding the h2 value change in temp cause positive sign will be put in that but in h1 ur write as negative sign why it as changed it confused me a lot pls clear that is ur mistake or what..
Bro I want problems of rankine cycle I'm saying that I have understood all the things what you said in this lecture But I want ranking cycle problems bro...
But how to identify that which type of compression cycle is given because there are many type like wet vapour after compression or dry vapour after compression
The refrigerant is leaving the evaporator as saturated vapor, then why you've shown that it is crossing the saturated line and is going to the super-heated region??...
abe submission values tho kar kyu direct answers daldera tune t2 ki value waise hi dali bagair solve kiye bhai agar batana hai samjana hai tho poora complete samjana kyu half bataraha hai bangali
Dear I have told each and every value ,how to find it. Step by step.. to find t2 you require simple mathematics.. how can you expect me to find out each and every numerical value in calculator...it is your job.. I think none of the teacher will do it for you...
@@RohitChowdhury_sajaysaini ok sir galat mat maniyey meri baato ka apne achha explain kiya lekin aur problems k video upload kariye kyu kal mera exam hai
best video among all videos related to vcrs in utube
Is there any explanation available for compression efficiency calculation, as in real world we will loose energy as compression losses?
Respected Sir...... Flash Chamber Suck the vapours ..... then after that .. where these vapours go from flash chamber ......and my 2nd question is that .... system capacity is 10 kw ..... and we get power requirement 3.19 kw ... does it mean that our system is extra efficient ...?
Hello sir i have Question about this problem, as in the problem it is not mentioned about superheating of refrigerant (the refrigerant leaves the evaporator as saturated vapor i.e it should be h1=h1 dash) then why we consider the superheating while solving problem .
"The refrigerant leaves the evaporator as saturated vapor": By this term, I thought the refrigerant goes to the compression at the saturated vapor condition. But the explanation shows the refrigerant superheated to point 1. I understand the degree of superheating equals the degree of subcooling. But the question explicitly says "saturated vapor". Would you please help me to understand why this term is used in the question?
At first you told degree of superheating=degree of subcooling, then it should be T1=-6. I ALSO GOT 411.92 as h1
Please take note that we are dealing with enthalpy and temp is only a function of enthalpy; it is the enthalpy (or ENERGY that is equal not the temp change it self)
where did you get 26°c?
Good video sir...why r u super heating? Qn is only sub cooling only sir?pls reply soon sir... tomorrow i have xam..
Whenever there is only subcoolong you have to consider super heating..
@@RohitChowdhury_sajaysaini why do we need to take super heating..??
Because the use of heatexchanger is mentioned in the question...
@@dhawalsao2142 th-cam.com/video/vQgYVWFHlkA/w-d-xo.html
Thanks
Hello Rohit, Your video was great but i would appreciate some clarification on two issues. 1. At 16:00 I am missing how h1 was arrived upon. 2. At 19:56 the reason for the introduction of natural log (ln). Sorry but I have been out of college for thirty years, HaHa . Thanking you in advance, Joseph
That is a formula we use in thermal engineering to find the amount of super heat present in vapour
gearhead0800 for #1 he used algebra...
By theory: deg of subcooling = deg of superheat
deg of subcooling = m(h3’-h3)
deg of superheat = m(h1-h1’)
m(h1-h1’) = m(h3’-h3); m is constant, it cancels
h1-h1’ = h3’-h3; substitute the values; find h1
For #2 reviewing isentropic process; cpln(T2/T1) is the derived formula in getting the change in entropy (s value)
Note that for isentropic process s1=s2 since entropy is constant; from TS Diagram and by algebra you can expand s1=s2 (expanded formula is the equation with ln) we expand for you to get T2 that you need for h2...
@@ottosudhakar4590 thank you
@@ottosudhakar4590 thanks for taking the time
sir, it was given in the question that the refrigerant leaves the evaporator as saturated vapour.... then why did you show it as super saturated at point 1 in the diagrams?... also please explain that in the question only Cpg is given... then why did you take Cpg to fing h3 of condenser outlet... where the refrigerant must be in liquid form.. so we need Cpw.. right?
See try to understand , no doubt that from evaporator saturated vapour is coming out.. but I have extended the the horizontal line from saturated vapour line to point no. 1 because in that portion the saturated vapour has further passed through a heat exchanger for superheating purpose
Evaporator works only in the portion 4 to 1'(saturated vapour line). From 1' to point 1 ,refrigerant is passing through heat exchanger for the purpose of superheating. I think now it is clear to you. Thank you
@@RohitChowdhury_sajaysaini If I consider no superheating, is it acceptable? Since the question says "the refrigerant leaves the evaporator as a saturated vapor." I assumed no superheating.
hello sir its great to watch the video but i have an issue regarding the calculation of h1 its 411.92 not 415.6 and based on that further calculation are also mistaken like the value of t1= -6 . thank you///
yes. At first he told degree of superheating=degree of subcooling, then it should be T1=-6. I ALSO GOT 411.92 as h1
I also find the same problem..
It tooks me a lot of time to understand
Due to one calculation mistake the entire solution is changed..
h1=411.92
Actually sir had taken Cp liquid equals to Cp of vapour. which was a mistake. Cp of liquid is not given in question. Atleast we don't know what is Cp of liuid. If you get Cp of liquid automatically all your values with match with sir's valve. since sir wrote them from book directly without any calculations. so they are correct. watch video one more time from 12.35 for better understanding.
thank you very much, sir, this video is very helpful and I was so confused all along after watching this video everything is now understandable. Sir my question is that why is your T2 in degrees Celcius after converting other temperatures into Kelvin?
In qsn it is mentioned that ref* leaving evaporator as saturated vapour then why u r extending that line on ph dig???👈
Let me know sir ???????
Because the system has what you called LIQUID-SUCTION VAPOUR HEAT EXCHANGER, which is stated in the question, meaning Subcooling and Superheating is present; that is why he mentioned that degree of subcooling is equal to deg of superheat...extending the process point to subcooled area indicates subcooling and extending the process point to superheated area is superheating
@@silvertongue1973 TQ so much
Your video was great ... but you should post full page pictures for review.
Thank you sir, I'm polytechnic lecturer n i got very nice information here
Thank you so much sir........
I hav one doubt,in question it is given that refrigerant leaves the evaporator as a saturated vapour then why are we superheating it from 1 to 1'?
Saurav Kumar we do not superheat it... mechanical system are never ideal....so superheating is a process we cannot control....it happens even if we dont want it to be...
@@devlimbu4762 is this applicable in every question that super heating will be done automatically..?
@@devlimbu4762 sahi bola
Sir your work is truly appreciable
Some more examples....
Waiting
Hey this a very helpful video.
Thank you Rahul
Sir, please let me know how this during T2 calculation we're taking Cp ln(t2/t1)
From the concepts of second law, we can say that ds=dQ/T(for int. Rev. Processes) . Now on integration of both sides you will get your final answer as s2-s1= m cp ln(t2/t1)
We have substituted Q = m cp dt( const. Pressure)
In the question superheating is not mentioned
Thank you so much for such a great video❤
thank u sir. this video helped me a lot...
Sir your video is very nice but there is a lots of calculation misktakes.
At 16:01 the value of h1 is entirely different from what you have calculated. It takes me a lot of hours to understand...
But at the end the answer are the same and I m happy with that😀
Sir my request to you please keep the calculation right.
And we are waiting for more videos from RAC subject.
can i ask if the problem says R134A has a zero degree fahrenheit subcooling? does it mean the condenser pressure and zero degree subcooling meet at the liquid saturation line? thank you so much for this video
How Cp of liquid is equal to Cp of vapour? Cp of liquid is not given in the question.
Same doubt.....LOL
How to see P H chart if table is not given in the question
thank you. bcz of you my concepts of VC's are cleared
Nagtilak Mahesh thank you very much...yo may watch my other videos also,when you need it
sir to finding the h2 value change in temp cause positive sign will be put in that but in h1 ur write as negative sign why it as changed it confused me a lot pls clear that is ur mistake or what..
Bro I want problems of rankine cycle
I'm saying that I have understood all the things what you said in this lecture
But I want ranking cycle problems bro...
But how to identify that which type of compression cycle is given because there are many type like wet vapour after compression or dry vapour after compression
Thank a lot sir, i got good concept in a short time
your value of h1 is wrong
In place of (cp of liq)@40℃ u take cp of vapour 12:39
exactly Cp of liquid is not given in question.
what that book do you used?
thank you very much sir....now i had basic knowledge about wt r&a.s ph and ts diagram and how to check values from data table
+madugula vinay thankyou very much
+madugula vinay thankyou very much.your support is always needed
god bless india
thanks sir
What if the degree of subcooling is different from the degree of superheating?
please make the video , numerical of vapour absorption cycle sir
The refrigerant is leaving the evaporator as saturated vapor, then why you've shown that it is crossing the saturated line and is going to the super-heated region??...
AYON BISWAS pls study more
How can we calculate Cp if it is not given??
Nis
Tq soo much sir its pleasure watching the video
What is the name of the book used?
th-cam.com/video/vQgYVWFHlkA/w-d-xo.html
Thank you sir
Perfectly explained.. Thanks a lot 😍😍😍
great job............what is the name of the book ??? thx
n.s qadan rk rajput
thank you
Can I contact with you sir??
Really very helpful sir! Thank you
Plz explain in telugu those peoples r suffering......with language
holy shittt!!!!!!!!
where did you get 26°c?
I got T2=60 C not 90 C
Prefer R.s . Khurmi
Nice #ASKAzad
Excellent.
Nice explanation
best teaching sir
thanks alot
how you calculate t3
abe submission values tho kar kyu direct answers daldera tune t2 ki value waise hi dali bagair solve kiye bhai agar batana hai samjana hai tho poora complete samjana kyu half bataraha hai bangali
Dear I have told each and every value ,how to find it. Step by step.. to find t2 you require simple mathematics.. how can you expect me to find out each and every numerical value in calculator...it is your job.. I think none of the teacher will do it for you...
In that equation you know all the values. You find out t2 . If you are not getting the same answer, then you comment..
@@RohitChowdhury_sajaysaini ok sir galat mat maniyey meri baato ka apne achha explain kiya lekin aur problems k video upload kariye kyu kal mera exam hai
th-cam.com/video/EYdmFlHgGYk/w-d-xo.html
Watch this video if you haven't
Brilliant
what book is that? help pleaseee :(
R.K.Rajput
how do you can say kj/s = kg/s ?
h1 you found wrong