What about entropy?

by: Camilo Botero G.*

In these times of energy crisis and awareness of the great impact that the use of conventional energies has on the environment, we understand more and more deeply about the energies we consume daily and how the vast majority are changing the climate of the world, but as far as entropy is concerned, we dedicate little or nothing to it and its ignorance is widespread.

When we take our thermodynamics courses at the university during our training as engineers, this subject is one of the most demanding and when we reach the second law of thermodynamics where the concept of entropy is implicit, we enter a great mystery that produces great frustration and finally we choose to use this thermodynamic property as useful as mysterious, taking their data from the tables of thermodynamic properties and with that data we make diagrams, T-s or h-s, which help us visualize the processes, the cycles and finally perform calculations of consumption and rejections of thermal energy, as well as production and consumption of mechanical power.

However. little or nothing we know about entropy, when in my courses I ask about the perception, which each student has of that property, comes the classical answer ... "it is a measure of disorder"... but that doesn't mean anything real, nor does it help us understand the true nature of this property. In these days in my cogeneration course in an Energy Efficiency Diploma, I received from two students two nice answers...

"... the entropy is: ... a good question..."

And... "teacher: what answer do you want; the romantic or the engineer..."

A professor at the National University of Colombia, my alma mater, told his students upon arriving at the subject of entropy: "... you already half understood the concept of temperature, now try to explain it to an illiterate ... and he continued: I will begin with the concept of entropy with you, then: temperature is illiterate, as entropy is a student of thermodynamics..."

There is another mystery of entropy that is known as the thermal death of the universe. If the definition of entropy is energy divided by absolute temperature, when it is cleared, the temperature is equal to the energy divided by the change in entropy. As according to the first law of thermodynamics energy is neither created nor destroyed (it is only converted in one way in another) it is therefore theoretically constant, in turn the denominator that is the delta of entropy, always increasing according to the second law of thermodynamics, leads to a value of temperature decreasing until reaching absolute zero, which would be that thermal death of the universe.

This conclusion is controversial in many ways, but from a simple mathematics of physics, it is incontrovertible.

This concept of entropy in addition to using it associated with energy where we could say that it is the energy weighted at its thermodynamic level (energy divided by its absolute temperature) is being used in other areas of knowledge; some examples are:

Intelligence
There are two types of intelligence from the point of view of entropy:
- Entropic Intelligence, which manifests itself when the brain is in "verbal logic" mode at this time the mind acts as an open entropic system, increasing the entropy and general uncertainty of the organism.
- Counterentropic Intelligence manifests itself when the brain is in "emotional" mode, in this mode the mind behaves as an open counterentropic system, concentrator of energy, decreasing the entropy and general uncertainty of the organism.

According to the Second Law of Thermodynamics, all systems tend to their maximum entropy. Living beings are systems that "take advantage" of this law to obtain energy from the degradation of other systems, relying on a precarious unstable equilibrium, but firm enough to allow their existence for an indefinite time.
Taken from Thermodynamic Theory of Intelligence, Chapter 5, (Taken from the internet).

It is necessary, then, to consider the initial conditions to discover what evolution is going to be (always remembering that entropy breaks with the idea of determinism). Georgescu-Roegen: Entropy and Economics (Taken from the Internet)

In computer science (Summary)
This article, from a new interdisciplinary theoretical approach, analyzes the question of the development of educational multimedia software, considering them as Interactive Multimedia Systems (SIM), relating them to principles of disciplines and concepts as diverse as thermodynamics, entropy, constructivism and general systems theory.

Introducing the concept of entropy as a process of transmission of information flows, the process of designing SIMs is oriented as a complex system accepting, from a constructivist perspective, that the student takes the leading role in the learning process, then, a new model of educational multimedia software should involve the student not only in the final stretch as a user, but it would have to intervene throughout the stage in which the learning process is carried out.

Where we can best visualize the effect of entropy growth in our industry, is in the case of refrigerant compression, where the inefficiency of the process is manifested in entropy delta that in the P-h diagram, classic to analyze the cooling cycle, a deviation to the right of the compression process is appreciated, leaving the refrigerant with a higher enthalpy and a higher temperature, thus translating into greater energy consumption.

In short, in order not to lengthen "this current dump" as any young student of thermodynamics would say when faced with the issue of entropy, our mission as engineers, technicians and as citizens of the world is to minimize the generation of entropy through more efficient equipment and systems and especially in the search for new technologies that optimize the conversion and use of energy.

ASHRAE is committed to achieving in buildings: The "near zero" energy balance in high-performance buildings used to be: The zero-based energy balance, but this is at the moment almost impossible. We must support that initiative by making our designs, assemblies, operation and maintenance as efficient as possible.

* Camilo Botero is the current president of ACAIRE and president of Camilo Botero Ingenieros Consultores Ltda. He has worked as a teacher in several Colombian universities, guilds and currently in ACAIRE in diploma courses of air conditioning projects, energy efficiency in air conditioning and refrigeration, cogeneration and trigeneration, applied psychometrics, thermodynamics, fluid mechanics, heat transfer and turbomachinery.