From a thermodynamics point of view heat transfer and entropy are very closely related, for example by the fundamental equation dQ=TdS for reversible heat transfer. If, however, one goes to the index of standard heat transfer text books (some of them with more than 1000 pages) one will not find a single entry of entropy or related topics (like entropy generation, exergy, ...). Is it that heat transfer people deliberately ignore entropy, because they decided they don't need it, or is it pure ignorace, which might be cured ... ???
Hi Heinz
it is a good question, i'm a teacher and researcher in thermodynamics field, i have same remark, many collegues whos worked in heat transfer domain ignore completly the basic definition of entropy, exergy and all concept of thermodynamics because i think those concepts are fundamentals and have philosophic side and it not easy to understand and apply them in practice, wheseas in heat transfer it is very easy to apply this science an real case .
ahmed
I've asked the same question many times! I think there are so many engineers who don't understand thermodynamics that they avoid it as much as possible. Most engineers have long forgotten that T=dH/dS)p=const., if they ever knew it in the first place. Some of the popular thermodynamic cycle modeling programs (e.g., GateCycle) don't even list entropy, let alone irreversibility. At least PEPSE lists entropy. Most engineers don't understand irreversibility at all and think exergy is some type of voodoo. It's important to teach students how to solve problems, but if they never come to understand why things work the way they do, that knowledge is wasted. Entropy is fundamental to the way the universe works. Just as you can't really appreciate motion until you understand why dV/dt = V dV/dX, you can't really appreciate energy until you can understand why S = k log(W), as inscribed over Boltzmann's tombstone. It's not incomprehensible. It's just rarely and poorly taught.
Agree. I am now researching about exergy, and so far we think that this is one of the best method to pinpoint inefficiencies. Fair enough, during schooltimes, my friends and I were not taught these subjects (entropy generation, irreversibilities nor exergy) so much - probably it's located mostly at the end of the syllabus in which lecturers may find it not so much important (ouch!), or even scarier that this thing is very taboo to be learned (difficult to understand and to apply).
At last, next time at my turn to teach, I'll definitely, God-willing, teach this stuff.
As usual, I come late to the question, but I want to express my doubts.
It is true that entropy flows accompanied to the heat (that is nothing else than energy in transit)but, we must remember that entropy is also produced. Entropy can flow also accompanied to the mass.
Every system that changes its state (more generally, I should say its thermodynamic state because thermodynamics is not only heat and work) produces entropy, because the process that make the state to change is unavoidably irreversible. So:
Heat produces entropy
Mass species diffusion produces entropy
Fluid flow produces entropy (unless viscosty is null)
A chemical reaction produces entropy
Electric current produces entropy
and so on.
I think we should ask ourselves also the question.
Why do only a few people take into account entropy in the last four cases?
I would like to know other people opinion on the matter.
Regards
Entropy: A concept that is not a physical quantity
https://www.researchgate.net/publication/230554936_Entropy_A_concept_that_is_not_a_physical_quantity
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