Thermodynamics: Laws, Entropy, Cycles, Exergy & Gibbs Free Energy Guide
Thermodynamics describes how energy is stored, transferred and converted. These guides take you from the basic principles and closed systems through entropy, cycles and exergy, then apply them to engines, powertrains and batteries.
Start here
Principles and energy basics.
Devices, entropy & cycles
The second law and the machines built on it.
Gibbs free energy & batteries
Thermodynamics of chemical systems.
Engines & powertrains
Thermodynamics in practice.
Frequently asked questions
What are the laws of thermodynamics?
The first law states that energy is conserved, and the second law states that entropy of an isolated system never decreases. Together they set limits on how energy can be converted.
What is entropy?
Entropy is a measure of how energy is dispersed in a system. The second law says that natural processes in an isolated system tend to increase total entropy.
What is exergy?
Exergy, also called availability, is the maximum useful work that can be obtained from a system as it comes into equilibrium with its surroundings.
What is Gibbs free energy?
Gibbs free energy combines enthalpy, temperature and entropy to predict whether a process can occur spontaneously at constant temperature and pressure.
Looking for something else? Browse all categories.