1. Evolution of the entropy of an open system. Entropy balance

Open systems have been studied from an energetic point of view in the article in paragraph 4.2. The entropic peculiarity of these systems must be taken into account.

For such a system (figure 1 ), the entropy variation dS is due to three causes:

• heat exchange with the external environment : $\sum \frac{\text{δ}{Q}_j}{T_j}$

  with T _j the system temperature at the heat exchange boundary;

• — internal irreversibilities dS ′ ;...