The relationship between computer science and physics is many-faceted, from the quantum mechanics principles that make semiconductors hum, to the concept of entropy that is the foundation of information theory. Entropy is a key concept of thermodynamics, and this specific facet of the physics world has in fact much more to teach to computer scientists than theoretical notions, in particular in this day and age where energy optimization issues are paramount over the whole spectrum of computer engineering, from high-performance computing (HPC) systems to embedded Internet of Things (IoT) modules. Essential engineering thermodynamics: a student’s guide, by Yumin Zhang, from Southeast Missouri State University, is a valuable addition to the wealth of literature that intends to teach thermodynamics and its applications.

The five chapters of this booklet (a bit shy of 70 pages) can be grouped into three main parts. The first two chapters introduce the foundations of thermodynamics, first its key notions (intensive properties such as temperature T and pressure P or extensive ones, as internal energy U) and then its three well-known laws (the energy E is conserved; the entropy S always increases; S=0 for perfect crystals at T=0 K). The whole presentation uses the ideal gas as a running example, which allows for simple analytical definitions and applications to be used to better ground the students’ knowledge. This part ends with a recollection of Maxwell differential laws that link P and T, their corresponding extensive properties volume V and S, and U and enthalpy H (a variant of U better adapted when V changes over time).

Chapters 3 and 4 form the second part of the book. Chapter 3 focuses on control mass processes, such as those found in closed containers in which the mass of the matter content doesn’t change. The main focus here is the study of phase changes, a key element in heat exchange systems such as some of the refrigeration modules often found in HPC infrastructures. From the start, the approach is definitely practical, moving from the ideal gas to physical ones, defined by various experimental tables that, for instance, yield for given T and P, the (specific) S for the superheated vapor phase of water. Many simple applications and practical uses of these tables are provided. Chapter 4 moves to a second important class of processes: the control volume ones, where fluids move from one container to another, as in turbines and pumps, while volume is kept constant. Among many examples here, diffusers, as used in jet engines or power plants, are discussed.

The last part of the book would be chapter 5, “Advanced Topics.” The computer scientist will be happy to find here a discussion of Shannon entropy and its relation with Boltzmann’s definition, presented in chapter 2. The microscopic view of equilibria, both in isolated systems and with heat transfer, is discussed in Sections 5.2 and 5.3, providing an interesting application of yet another thermodynamics property, the Gibbs function G. After a brief description of the thermodynamical aspects of crystal growth using molecular beam epitaxy, a key process in chip manufacturing, a quite clear introduction to the notion of chemical potential is given, with a nice application to osmotic pressure. Even more unexpected applications of thermodynamics, to dissipative structures and even the very fabric of social bonds, end the book.

If the book’s target audience is clearly undergraduate students, its readability and down-to-earth approach guarantee it can also be used as a lightweight refresher for more seasoned computer scientists. It’s unfortunate that an index and maybe some exercises have not been included, but the shortness of the book might explain this. Yet, one of my greatest regrets is the lack of discussion about the difference between exact differentials, as in dT or dP, and inexact ones such as δQ. This kind of notational subtlety may be one of the reasons that thermodynamics is often seen as a difficult subject to master, as candidly admitted by the author in his biography. Hopefully this short addition to the literature can help, at least with regards to the other subtle aspects of this important science.