Non-equilibrium thermodynamics

Non-equilibrium thermodynamics is the study of how heat (energy) moves around in systems that are not in balance. This means that the temperature and pressure of one part of the system is different from another part. Heat is always moving from an area of higher temperature to an area of lower temperature and this movement of heat creates changes in the system. For example, a hot cup of coffee will cool off as the energy moves from the hot coffee to the cooler air. This type of energy transfer is described by non-equilibrium thermodynamics.