| Rankine | |
|---|---|
| Unit of | Temperature |
| Symbol | R, °R, °Ra |
| Named after | Macquorn Rankine |
| Conversions | |
| 491.67 Rin ... | ... is equal to ... |
| Kelvin scale | 273.15 K |
| Celsius scale | 0 °C |
| Fahrenheit | 32 °F |
TheRankine scale (/ˈræŋkɪn/RANG-kin) is anabsolute scale ofthermodynamic temperature named after theUniversity of Glasgowengineer andphysicistMacquorn Rankine, who proposed it in 1859.[1]
Similar to theKelvin scale, which was first proposed in 1848,[1] zero on the Rankine scale isabsolute zero, but a temperature difference of one Rankine degree (°R or °Ra) is defined as equal to oneFahrenheit degree, rather than theCelsius degree used on the Kelvin scale. In converting from kelvin to degrees Rankine, 1 K =9/5 °Ra or 1 K = 1.8 °Ra. A temperature of 0 K (−273.15 °C; −459.67 °F) is equal to 0 °Ra.[2]
The Rankine scale is used in engineering systems where heat computations are done using degrees Fahrenheit.[3]
The symbol fordegrees Rankine is °R.[2] However, historical texts referring to "°R" are much more likely to mean the historically quite commonRéaumur scale.[4] As there is also theRømer scale, it is better to use °Ra to be unambiguous. By analogy with the SI unitkelvin, some authors term the unitRankine, omitting the degree symbol.[5][6]
Some temperatures relating the Rankine scale to other temperature scales are shown in the table below.
| Scale | ||||||
|---|---|---|---|---|---|---|
| Kelvin | Rankine | Fahrenheit | Celsius | Réaumur | ||
| Temperature | Absolute zero | 0 K | 0 °Ra | −459.67 °F | −273.15 °C | −218.52 °Ré |
| Freezing point ofbrine[a] | 255.37 K | 459.67 °Ra | 0 °F | −17.78 °C | −14.224 °Ré | |
| Freezing point of water[b] | 273.15 K | 491.67 °Ra | 32 °F | 0 °C | 0 °Ré | |
| Boiling point of water[c] | 373.1339 K | 671.64102 °Ra | 211.97102 °F | 99.9839 °C | 79.98712 °Ré | |
