ABSTRACT
In the first part of this book, we introduced the basic concepts of thermodynamics without resorting to the notion of entropy, which can be difficult to master for some learners. In this chapter, we introduce it as simply as possible and discuss the main implications of the second law of thermodynamics, in particular the Carnot cycle and the irreversibilities that take place in real processes.
The (T, s) entropy chart is presented, and the cycles of the simple energy systems are plotted in it, with a discussion about their difference with the Carnot cycle.
Finally, a significant place is devoted to exergy methods that are increasingly regarded as among the best suited to perform optimization studies, as they can take into account both the amount of energy put into play and its quality. To simplify the construction of exergy balances, we use the productive structures, network of productive and dissipative units (PDUs).
