Heat cycles and engines

In the previous chapter we discovered that a transformation is reversible if and only if the total entropy does not change: $\Delta S_\text{tot} = 0$. This condition selects a special set of ideal transformations — the only ones representable as well-defined curves on the $P$-$V$ diagram. On these are built heat engines: cyclic devices that turn heat into work (engines) or work into heat (refrigerators, heat pumps). The chapter culminates in the Carnot cycle and its maximum efficiency, a universal ceiling imposed by the second law.

Sections

• Reversible transformations
• P-V and ln P – ln V diagrams
• Thermodynamic cycles
• Heat engines and efficiency
• Solving a complete cycle

Reflections

• The price of work
• Why Carnot is a beacon

Exercises

• All worked exercises of the chapter