Opened 12 years ago

Closed 9 years ago

# request addition of Rankine and/or temperature difference units

Reported by: Owned by: tara_athan Gunther Schadow minor Revision 1.9

### Description

When temperature data is expressed as a difference (e.g. deviation from an average) the units are on a ratio scale. So to convert a Celsius temperature difference to a Fahrenheit temperature difference, we would just multiply by 9/5, rather than using the affine function. This could be accomplished by using Kelvin and Rankine as the units. Alternatively, a synonymous unit of something like d_Cel and d_Fahr could more clearly state the distinction.

### comment:1 Changed 10 years ago by Gunther Schadow

Milestone: → Revision 1.9

It makes sense to add degree Rankine.

"Rankine is a thermodynamic (absolute) temperature scale named after the Glasgow University engineer and physicist William John Macquorn Rankine, who proposed it in 1859. (The Kelvin scale was first proposed in 1848.)

The symbol for degrees Rankine is °R[1] (or °Ra if necessary to distinguish it from the Rømer and Réaumur scales). Zero on both the Kelvin and Rankine scales is absolute zero, but the Rankine degree is defined as equal to one degree Fahrenheit, rather than the one degree Celsius used by the Kelvin scale. A temperature of −459.67 °F is exactly equal to 0 °R."

There is also the Réaumur scale:

"The Réaumur scale (°Ré, °Re, °R), also known as the "octogesimal division",[1] is a temperature scale in which the freezing and boiling points of water are set to 0 and 80 degrees respectively. The scale is named after René Antoine Ferchault de Réaumur, who first proposed something similar in 1730.[2]

The Réaumur scale saw widespread use in Europe, particularly in France and Germany as well as Russia, as referenced in works of Dostoyevsky, Tolstoy, and Nabokov.[4][5][6] By the 1790s, France chose the Celsius scale for the metric system over the Réaumur measurements.[2] Its only modern use is in the measuring of milk temperature in cheese production. It is used in some Italian dairies making Parmigiano-Reggiano and Grana Padano cheeses and in Swiss Alp cheeses.[7]"

For the modern use, it is a good idea to put it in also.

### comment:2 Changed 10 years ago by Gunther Schadow

Owner: set to Gunther Schadow new → assigned

### comment:3 Changed 9 years ago by Gunther Schadow

Resolution: → fixed assigned → closed

Rankine has been added with #146.

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