Rankine | |
---|---|
Unit of | Temperature |
Symbol | R, °R, °Ra |
Named after | Macquorn Rankine |
Conversions | |
x R in ... | ... corresponds to ... |
Kelvin scale | 5/9 x K |
Celsius scale | (5/9 x − 273.15) °C |
Fahrenheit | (x − 459.67) °F |
The Rankine scale (/ˈræŋkɪn/) is an absolute scale of thermodynamic temperature named after the University of Glasgow engineer and physicist Macquorn Rankine, who proposed it in 1859.[1]
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]
The Rankine scale is still 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, the 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.
Temperature | Kelvin (K) | Celsius (°C) | Fahrenheit (°F) | Rankine (°R) |
---|---|---|---|---|
Absolute zero | 0 | −273.15 | −459.67 | 0 |
Freezing point of brine[a] | 255.37 | −17.78 | 0 | 459.67 |
Freezing point of water[b] | 273.15 | 0 | 32 | 491.67 |
Boiling point of water[c] | 373.1339 | 99.9839 | 211.97102 | 671.64102 |