Energy Level Change in Adiabatic Reversible Process

In summary, entropy is a measure of the amount of available energy levels in a system. The availability of energy levels increases with an increase in system volume and temperature, while it decreases with an increase in system pressure. In adiabatic reversible compression and expansion, no heat is exchanged with the surroundings and therefore no entropy is transferred. Since the process is reversible, no entropy is generated within the system due to the canceling effects of pressure and temperature changes. However, the equation for this canceling effect is not specified. There is more information available on the entropy transfer across system boundaries, but less on the generation of entropy. Another approach to understanding entropy is through information theory, with recommended resources being the book "Principles of Statistical Mechanics
  • #1
Sorade
53
1
Hello,

I am currently trying to get my head around the concept of entropy. One way to understand it is that it can be related to the amount of available energy levels in a system.

From what I read, the availability of energy levels in a system:

1) increase with an increase in the system volume by bringing energy levels closer
2) increase with an increase in the system temperature by increasing available energy to reach more levels
3) decrease with an increase in the system pressure by making energy levels further apart

I am currently interested in an example of adiabatic reversible compression and expansion.

Since the process is adiabatic, I know that no heat is exchanged with the surroundings and that therefore there is no entropy transfer to/from the system.

Since the process is reversible then no entropy is generated ... and this is where I'm unsure ... I know that the volume of my compressor doesn't change, so that volume doesn't contribute to changes in availability of energy levels within my compressor (system). I know that both my pressure and temperature increase though and that each have an opposite effect on the availability of energy levels within the system. Therefore I assume that the effects of both cancel out and that overall the availability of energy levels within the system doesn't change and that no entropy is generated within the system. If I am correct in my understanding of the process, I can't find anywhere the equation which shows that the increase in pressure and temperature cancel each other out in when it comes to generating entropy.

There is a lot about the dS = dQ/T which is about the entropy transfer across the system boundaries but I can't find much about the entropy generation.
 
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  • #2
Another modern approach to grasp the idea behind entropy is based on information theory. A very good book on this is

A. Katz, Principles of Statistical Mechanics, W. H. Freeman and Company, San Francisco and London, 1967.

You find also an introduction in the following manuscript

http://th.physik.uni-frankfurt.de/~hees/publ/stat.pdf
 

Related to Energy Level Change in Adiabatic Reversible Process

1. What is an adiabatic reversible process?

An adiabatic reversible process is a thermodynamic process in which there is no transfer of heat or matter between the system and its surroundings. This means that the system is completely isolated from its surroundings, allowing it to change its energy level without any outside influence.

2. How does energy level change in an adiabatic reversible process?

In an adiabatic reversible process, the energy level changes due to the work done on or by the system. This work can be in the form of mechanical work, such as compression or expansion of a gas, or electrical work, such as charging or discharging a battery.

3. What is the relationship between energy level change and temperature in an adiabatic reversible process?

In an adiabatic reversible process, the temperature of the system changes as its energy level changes. This is because the energy level is directly related to the average kinetic energy of the particles in the system, which is what we measure as temperature.

4. What are the applications of adiabatic reversible processes?

Adiabatic reversible processes are used in many industrial and scientific applications, such as in refrigeration and air conditioning systems, gas turbines, and chemical reactions. They are also important in the study of thermodynamics and energy conservation.

5. How is an adiabatic reversible process different from an adiabatic irreversible process?

The main difference between adiabatic reversible and irreversible processes is that in an irreversible process, there is some form of energy dissipation, such as friction or heat transfer, which cannot be reversed. This means that the system will not return to its original state after the process is completed, whereas in a reversible process, the system will return to its original state.

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