[Encyclios]

Thermodynamic transformation of a system

It takes the name of thermodynamic transformation (or thermodynamic process) of a system, any modification which involves the variation of at least one of its internal properties. Depending on whether this variation is infinitesimal or finite we will have an infinitesimal or finite transformation.

It is necessary to distinguish a transformation from a simple physical phenomenon: for example, a simple system consisting of a fluid which changes its position in space without other consequences, represents a physical phenomenon, but certainly not a transformation: in fact, if the fluid changes its position, probably changes its potential energy (related to quota), but this is an external properties of the system. The same applies if the system under examination changes shape but remains unchanged in volume. A particular transformation is the so-called cycle: it is a finite transformation that brings the system back to the same state from which it started.