Talk:Rankine cycle

message: First thing to show is p-v diagram.
Why is the word steam in the intro.  — Preceding unsigned comment added by 128.118.7.237 (talk) 22:05, 22 November 2020 (UTC)

message: Could someone explain why in Process 3–4 the work is assumed to be equal to the change of enthalpy, rather than to the change of internal energy?
For an adiabatic transformation, the work is equal to the change of internal energy (https://en.wikipedia.org/wiki/Internal_energy) dW=-PdV. For the work to be equal to VdP, the potential PV would have to be conserved ( d(PV)=0 ), which is true, for an ideal gas, only if the transformation is isothermal.
Percht (talk) 21:06, 27 January 2021 (UTC)
thread_title: Work: W=VdP vs W=-PdV

message: why is there no PV diagram?  — Preceding unsigned comment added by 86.26.165.15 (talk) 12:53, 9 March 2015 (UTC)
replies: text: Point taken.  Adding variable definitions. --ABQCat 22:01, 10 Dec 2004 (UTC)

text: Cool. I haven't had to do any thermodynamics in years, so I'd have had to dig out a book (horrors!) :) --Cmprince 22:36, 10 Dec 2004 (UTC)
replies: text:  Yeah.  I noticed that there was no article on the Rankine cycle after I finished with my thermodynamics course last semester, and decided (perhaps as a form of therapy to deal with the horrid subject matter?) to regurgitate what I had managed to learn and what I found useful into this article.  Hopefully it'll help other people who are just as clueless as I was at points.  --ABQCat 22:40, 10 Dec 2004 (UTC)
thread_title: Untitled

message: It is stated in the introduction that: "This cycle generates about 90% of all electric power used throughout the world". The reference is from 2000 and is only for USA. Looking at the Key World Energy Statistics 2011 published by the International Energy Agency one sees at page 24 that hydro is 16.2% in 2009. We need to also take into account Brayton cycle and combined cycles. So I am fairly new here in the editing process... do I just delete the statement. Volusteinn (talk) 18:20, 5 March 2012 (UTC)
replies: text: I agree, I looked at some IEA reports on electricity production by fuel and I counted coal, nuclear, biomass and solar thermal. Natural gas and petrol(diesel) would be used in Brayton and Diesel cycles respectively. By my crude figure, I think we can safely say that at least 55% of world wide electricity production in 2009 was by rankine cycle steam, if all fuels above were solely used for it. Unfortunately, I have searched for world electricity production by generation method to no avail and this was the closest I got. It also means it is not a verifiable source.150.203.45.42 (talk) 03:55, 4 April 2012 (UTC)
thread_title:  Test in introduction is wrong 

message: Some typical and maximum efficiency levels would be useful. Tobyw 12:14, 8 March 2006 (UTC)
replies: text: "However, the thermal efficiency of actual large steam power stations and large modern gas turbine stations are similar." Large hardcoal fired power stations (new) have an eta_el = 46%, whereas the best gas turbine is around 40% - however CCGT go beyond >60%. So this sentence should be amended or stated more precisely. --Gunnar (talk) 06:55, 26 July 2018 (UTC)
thread_title:  Efficiency 

message: I've uploaded a new vector version of the graph to the wiki commons.
Although I applied to make it almost pixel-perfect, I would like someone more confortable with this page to move on the article.
As you're reading this, I will have marked the old image as superceded.
MaxDZ8 talk 16:04, 24 May 2007 (UTC)
thread_title:  New graph. 

message: I've reworded the processes section with a new diagram, Data was plotted from IAPWS IF-97 in SI units. I'll be changing other parts of the article very soon too, equations need tidying up a little and perhaps some more info about where this cycle is used and why it is used above others. Also super heating among other things needs covering. I've also made another diagram of a schematic that I'll try to include, Ts diagrams don't mean all that much to non-Engineering/Physics students. Andrew.Ainsworth 09:40, 23 August 2007 (UTC)
thread_title:  Rewrite (and a question)

message: I inflict (lecture?!) thermodynamics to undergraduates,and I have made a couple of changes to this article.
I have put in a few more diagrams for the reheat and regenerative cycles. I have a load more, but I wanted to keep the size down. 
I have moved the description to the top, to let people know what they are reading about. 
I have also put in a few more technical bits about overall efficiencies and Carnot efficiencies. 
I have also clarified the reverse Rankine cycle bit. This is still a bit tenuous and it migh be best to remove it entirely!  (Donebythesecondlaw 13:32, 19 September 2007 (UTC)
thread_title:  Various changes. 

message: Replaced layout picture with better quality one, opinions? Andrew.Ainsworth (talk) 16:48, 29 November 2007 (UTC)
thread_title:  New image 

message: What is "heat addition temperature"? --Milkbreath 16:42, 2 December 2007 (UTC)
thread_title:  Description section 

message: Last sentence: what does it mean for a Rankine cycle to be "exposed"? --Milkbreath 16:54, 2 December 2007 (UTC)
replies: text: Don't imagine for one second that I have the first clue about thermodynamics. I don't. I just bounce around copyediting, and I like things to make sense even when I don't understand what that sense is. As for raising the profile, one can submit an article for different reviews. I believe the first step is to submit for peer review. You should probably also bring this up on the talk page for WikiProject Physics. I would do it myself, but whoever does it should be able to respond to criticisms and suggestions by altering the content, and, as I said, that ain't me. --Milkbreath 18:05, 3 December 2007 (UTC)
thread_title:  Processes of the Rankine cycle section 

message: Could come in handy for someone, you never know.
PV pdiagrams are only of interest for closed systems. As the integral of pdv is the work.  — Preceding unsigned comment added by 84.51.137.53 (talk) 18:21, 9 March 2015 (UTC)
thread_title:  How about a P-v diagram? 

message: As an engineer I once worked in a steam plant and as best I can I racall, some condensation was allowed in the turbine, up to a maximum of about 12% moisture, after which erosion of the turbine blade by the water droplets was serious.  I believe the statement made at steam turbine#Steam Supply and Exhaust Conditions stating 10% exit moisture is probably correct. Phmoreno (talk) 14:07, 29 October 2010 (UTC)
thread_title:  Questioning statement about lost heat of vaporization 

message: This is not my field of expertise but I would like to check the text against citations- could someone devote a little time to providing some! A start class article:= The article has a usable amount of good content but is weak in many areas, usually in referencing. This describes this perfectly- it is not a C class article till this is rectified.--ClemRutter (talk) 12:22, 5 January 2011 (UTC)
thread_title:  Inline citations 

message: If the entry temperature of steam turbines is allegedly limited to 525 degrees because of the creep limit of stainless steel,     then how do gas turbines have an entry temperature of 1500 degrees ?     Why not make the steam turbines out of whatever it is that the gas turbines are made from - presumably not stainless steel.  Actually I think the alleged entry temperature limit of steam turbines is spurious.Eregli bob (talk) 15:55, 2 August 2011 (UTC)
thread_title:  Inconsistency 

message: < This (evaporation) energy is lost to the cycle because the condensation that can take place in the turbine is limited to about 10% in order to minimize blade erosion >
This is not correct. The energy is lost to the cycle because of the second law! The shape of the saturation line (and hence the steam condition at condenser entry) has nothing to do with it. 86.181.114.173 (talk) 11:35, 14 September 2011 (UTC)
thread_title:  Energy loss 

message: 'The efficiency of the Rankine cycle is limited by the high heat of vaporization of the working fluid'
Try as I might, I cannot make any sense of that statement. It may have to go.
109.145.108.66 (talk) 21:23, 13 July 2015 (UTC)
thread_title:  Description 

message: Substituted at 03:55, 30 April 2016 (UTC)
thread_title: Assessment comment

message: I feel some more detailed information should be added like this accordingly to demonstrate the stages of how the Rankine Cycle works and it would as well help when making use of the Equations in calculations on Rankine Cycle to know what equation is next for usage; 
=======================================
The Rankine Cycle works in this order continuously;
Pump===>Boiler===>Turbine===>Condenser.
For Pump work
Note: The function of the ```Pump``` is to move fluid(liquid or gas) into the ```Boiler```, so in that process, a work is done, to calculate that work done, we have to use the equation below;
w(pump) = [dot]W(pump) / m(dot) = h2 - h1
For Boiler( heat addition);
Note: The function of the ```Boiler``` is to increase the temperature of the fluid(liquid or gas) moved into it(the Boiler) by the Pump, so in that process, there is an added heat, to calculate the heat added, we have to use the equation below;
q(in) = [dot]Q(in) / [dot]m = h3 - h2
For Turbine work; 
Note: A Turbine is a rotary machine that uses the kinetic energy of a continuous stream of fluid(liquid or gas) to turn a shaft.
Therefore, a turbine does a work, to find the work done by the turbine, we have to use the equation below
w(turb) = [dot]W(turb) / m(dot) = h3 - h4
For Condenser( heat rejection);
Note: The function of the ```Condenser``` is to cool the temperature of  the fluid extracted into it(the Condenser) by the ```Turbine``` , so in that process, there is an added heat, to calculate the heat added, we have to use the equation below;
q(out) = [dot]Q(out) / [dot]m = h4 - h1
Note: the fluid(liquid or gas) extracted into the condenser from the turbine is then moved by the pump again [i.e it returns to the beginning and then repeats itself in the same sequence(Cycle)].
===========================================
Thank you. 
I would have loved to edit it myself, but I'm having difficulties editing the mathematical expressions, so i dont want to mess with. Its saying parse error. Victoriod (talk) 11:55, 17 July 2019 (UTC)
thread_title:  Under the Equations for the Rankine Cycle 

message: Thank you. 
I would have loved to edit it myself, but I'm having difficulties editing the mathematical expressions, so i dont want to mess with. Its saying parse error. Victoriod (talk) 11:55, 17 July 2019 (UTC)
thread_title: ===============================