In thermodynamics, the principle of increasing entropy or principle of entropy increase is an oft-used synonym for the second law of thermodynamics, or second main principle, referring to the idea that all real processes occurring in a system will occur such that an increase in the entropy of the system results, which is a mathematical way of saying, loosely, that more heat (or specifically the state quantity of heat divided by temperature Q/T, i.e. entropy) went into the system than went out, meaning that part of the heat was converted into the work in the irreversible repositioning of the particles of the system at the end of the heat cycle. [1] The principle of increasing entropy is said to be contained in the Clausius inequality. [2]

See also
● Surroundings entropy increase
● Entropy consumption

References
1. Hauriou, Maurice. (1899). Leçons sur le Mouvement Social (Lessons on Social Movement) (principle of increasing entropy, pg. 3). Paris: Larose.
2. Finn, Colin B.P. (1993). Thermal Physics (section: 5.5: The Principle of Increasing Entropy, pgs. 77-). CRC Press.

External links
● Khemani, Haresh. (2008). “The Principle of Increase of Entropy”, BrightHub.com, Aug. 16.
● Increase in entropy principle – Ohio.edu.
● Increase in entropy – Theory.ph.man.ac.uk.