**Thermodynamic Cycles**

A **thermodynamic cycle** consists of a collection of thermodynamic processes transferring heat and work, while varying pressure, temperature, and other state variables, eventually returning a system to its initial state. In the process of going through this cycle, the system may perform work on its surroundings, therefore acting as a heat engine.

State quantities depend only on the thermodynamic state, and cumulative variation of such properties adds up to zero during a cycle. Process quantities (or path quantities), such as heat and work are process dependent, and cumulative heat and work are non-zero. Since the change in internal energy (a state quantity) over the course of a cycle is zero, the first law of thermodynamics dictates that the net heat input is equal to the net work output over a cycle. The repeating nature of the process path allows for continuous operation, making the cycle an important concept in thermodynamics. Thermodynamic cycles are often represented mathematically as quasistatic processes to model the workings of an actual device.

Read more about Thermodynamic Cycles: Heat and Work, Modelling Real Systems, Well-known Thermodynamic Cycles, State Functions and Entropy, See Also

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**thermodynamic cycles**are usually made out of four

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**Thermodynamic Cycles**- See Also

... Entropy Economizer

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### Famous quotes containing the word cycles:

“The stars which shone over Babylon and the stable in Bethlehem still shine as brightly over the Empire State Building and your front yard today. They perform their *cycles* with the same mathematical precision, and they will continue to affect each thing on earth, including man, as long as the earth exists.”

—Linda Goodman (b. 1929)