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A Assuming an altitude of 194 metres above mean sea level (the worldwide median altitude of human habitation), an indoor temperature of 23 °C, a dewpoint of 9 °C (40.85% relative humidity), and 760 mmHg sea level–corrected barometric pressure (molar water vapor content = 1.16%). B Calculated values *Derived data by calculation.
An enthalpy–entropy chart, also known as the H–S chart or Mollier diagram, plots the total heat against entropy, [1] describing the enthalpy of a thermodynamic system. [2] A typical chart covers a pressure range of 0.01–1000 bar , and temperatures up to 800 degrees Celsius . [ 3 ]
Description: Blue lines indicate vapor quality, mass percentage in the saturated mixture that is in gas phase . Black lines indicate pressure in pounds per square inch . Grey lines indicate specific volume in square feet per pound-mass of steam
Data in the table above is given for water–steam equilibria at various temperatures over the entire temperature range at which liquid water can exist. Pressure of the equilibrium is given in the second column in kPa. The third column is the heat content of each gram of the liquid phase relative to water at 0 °C.
Superheated steam is steam at a temperature higher than its vaporization point at the absolute pressure where the temperature is measured. Superheated steam can therefore cool (lose internal energy ) by some amount, resulting in a lowering of its temperature without changing state (i.e., condensing ) from a gas , to a mixture of saturated vapor ...
Since an increment of temperature of one degree Celsius is the same as an increment of one kelvin, that is the same as joule per degree Celsius per kilogram: J/(kg⋅°C). Sometimes the gram is used instead of kilogram for the unit of mass: 1 J⋅g −1 ⋅K −1 = 1000 J⋅kg −1 ⋅K −1 .
This pressure is given by the saturated vapour pressure, and can be looked up in steam tables, or calculated. [9] As a guide, the saturated vapour pressure at 121 °C is 200 kPa, 150 °C is 470 kPa, and 200 °C is 1550 kPa. The critical point is 21.7 MPa at a temperature of 374 °C, above which water is supercritical rather than superheated ...
When liquid water becomes steam, it increases in volume by 1,700 times at standard temperature and pressure; this change in volume can be converted into mechanical work by steam engines such as reciprocating piston type engines and steam turbines, which are a sub-group of steam engines.