Absolute temperature scale using Fahrenheit degrees
This article is about the temperature scale. For the idealized thermodynamic cycle for a steam engine, see Rankine cycle. For the scale measuring recovery after stroke, see Modified Rankin Scale.
Similar to the Kelvin scale, which was first proposed in 1848,[1] zero on the Rankine scale is absolute zero, but a temperature difference of one Rankine degree (°R or °Ra) is defined as equal to one Fahrenheit degree, rather than the Celsius degree used on the Kelvin scale. In converting from kelvin to degrees Rankine, 1 K = 9/5 °R or 1 K = 1.8 °R. A temperature of 0 K (−273.15 °C; −459.67 °F) is equal to 0 °R.[2]
Usage
The Rankine scale is used in engineering systems where heat computations are done using degrees Fahrenheit.[3]
The symbol for degrees Rankine is °R[2] (or °Ra if necessary to distinguish it from the Rømer and Réaumur scales). By analogy with the SI unit kelvin, some authors term the unit Rankine, omitting the degree symbol.[4][5]
Some temperatures relating the Rankine scale to other temperature scales are shown in the table below.
^The freezing point of brine is the zero point of Fahrenheit scale, old definition, see: Grigull 1986
^The ice point of purified water has been measured to be 0.000089(10) degrees Celsius – see Magnum 1995
^For Vienna Standard Mean Ocean Water at one standard atmosphere (101.325 kPa) when calibrated solely per the two-point definition of thermodynamic temperature. Older definitions of the Celsius scale once defined the boiling point of water under one standard atmosphere as being precisely 100 °C. However, the current definition results in a boiling point that is actually 16.1 mK less. For more about the actual boiling point of water, see VSMOW in temperature measurement.
