3. Detailed illustration: coaxial heat exchanger

3.1 General relations

Generally speaking, to calculate entropy production, it is necessary to know the spatial and/or temporal profiles of the flows and driving forces, and therefore a detailed model of the process must be established and solved. In many cases, this involves numerical calculations. In some simple cases, entropy production can be calculated directly.

The following example illustrates how entropy production in a process can be calculated via the detailed model, and also allows us to discuss the orders of magnitude encountered. We take the example of the steady-state co-axial shell-and-tube heat exchanger used to illustrate the above theorems, without considering mechanical dissipation, and briefly recall the basic theory here. For reasons of...