Math 2.0

Classical thermodynamics, heat transfer Definition

Thermodynamic cycle

Builds on Thermodynamic systemThermodynamic stateState functionHeatThermodynamic workFirst law of thermodynamicsInternal energyQuasistatic processIsothermal process

Definition

Let SS be a thermodynamic system, called the working substance. A thermodynamic cycle of SS is a finite sequence of processes that take SS through successive states. The final state of the last process must be the initial state of the first.

Remarks

Every state function takes the same value at the end as at the start; in particular the change of internal energy over the cycle is 00. By the first law of thermodynamics, the net heat QQ absorbed over the cycle equals the net work WW done by SS. For a closed simple system whose processes are all quasistatic, W=∮p dVW = \oint p\, dV, the area enclosed by the loop in the (V,p)(V, p) plane, counted positive for a clockwise loop. Example: expand an ideal gas isothermally from V1V_1 to V2V_2 at temperature T1T_1, then cool it at constant volume to T2<T1T_2 < T_1. Then compress it isothermally back to V1V_1 at T2T_2, and heat it at constant volume back to T1T_1. The gas returns to its initial state (T1,V1)(T_1, V_1), so this is a cycle. A non-example: the isothermal expansion from V1V_1 to V2V_2 alone is not a cycle, because it ends in a state with a different volume.

Reading path

To understand this page from the ground up, read these 10 pages in order. The foundations come first.

Show the path as a graph
Heat, concept, no evidence levelHeatconceptInternal energy, concept, no evidence levelInternal energyconceptIsothermal process, concept, no evidence levelIsothermal processconceptQuasistatic process, concept, no evidence levelQuasistatic processconceptState function, concept, no evidence levelState functionconceptThermodynamic state, concept, no evidence levelThermodynamic stateconceptThermodynamic system, concept, no evidence levelThermodynamic systemconceptThermodynamic work, concept, no evidence levelThermodynamic workconceptFirst law of thermodynamics, statement, no evidence levelFirst law of thermody…statementThermodynamic cycle, definition, no evidence levelThermodynamic cycledefinition
Each page uses the pages above it. The colour of the bar on a box shows how strong the evidence is, and the box also gives it as text. The list has the same pages.
  • no evidence level
  1. Heat concept
  2. Internal energy concept
  3. Isothermal process concept
  4. Quasistatic process concept
  5. State function concept
  6. Thermodynamic state concept
  7. Thermodynamic system concept
  8. Thermodynamic work concept
  9. First law of thermodynamics statement
  10. Thermodynamic cycle definition

Further reading

  1. Web https://en.wikipedia.org/wiki/Thermodynamic_cycle
About this page
TagZ4ECWDNHFN
URIm2://Z4ECWDNHFN
Kinddefinition
WritingW0 stub
MSC80A10, 80A05
DefinesThermodynamic cycle
UsesThermodynamic system, Thermodynamic state, State function, Heat, Thermodynamic work, First law of thermodynamics, Internal energy, Quasistatic process, Isothermal process
Changed3 November 2026

Markdown · JSON · Edit on GitHub

What this page needs for W1

  • an inventory row: the row of the inventory that the node accounts for (0 of 1)
  • a source with a locator (0 of 1)

The writing levels say how complete the text of a page is. They do not measure its truth.

What links here

No page links to this page yet.