Editing Phase diagram (section)

====Other thermodynamic properties====
In addition to temperature and pressure, other thermodynamic properties may be graphed in phase diagrams.  Examples of such thermodynamic properties include [[specific volume]], [[specific enthalpy]], or specific [[entropy]].  For example, single-component graphs of temperature vs. specific entropy (''T'' vs. ''s'') for water/[[steam]] or for a [[refrigerant]] are commonly used to illustrate [[thermodynamic cycle]]s such as a [[Carnot cycle]], [[Rankine cycle]], or [[vapor-compression refrigeration]] cycle.

Any two thermodynamic quantities may be shown on the horizontal and vertical axes of a two-dimensional diagram. Additional thermodynamic quantities may each be illustrated in increments as a series of lines—curved, straight, or a combination of curved and straight. Each of these '''iso-'''lines represents the thermodynamic quantity at a certain constant value.

<gallery mode="packed" heights="250" caption="Chart in U.S. units" class="skin-invert-image">
File:Mollier enthalpy entropy chart for steam - US units.svg|enthalpy–entropy (''h''–''s'') diagram for steam
File:Pressure-enthalpy chart for steam, in US units.svg|pressure–enthalpy (''p''–''h'') diagram for steam
File:Temperature-entropy chart for steam, imperial units.svg|temperature–entropy (''T''–''s'') diagram for steam 
</gallery>