Guide for the Use of the International System of Units (SI)

 
Heat Flow Rate 
British thermal unit
IT
per hour (Btu
IT
/ h) ............ watt (W) ............................................... 2.930 711 E−01 
British thermal unit
th
per hour (Btu
th
/ h).............. watt (W) ............................................... 2.928 751 E−01 
British thermal unit
th
per minute (Btu
th
/ min) ..... watt (W) ............................................... 1.757 250 E+01 
British thermal unit
IT
per second (Btu
IT
/ s).......... watt (W) ............................................... 1.055 056 E+03 
British thermal unit
th
per second (Btu
th
/ s)........... watt (W) ............................................... 1.054 350 E+03 
calorie
th
per minute (cal
th
/ min) .......................... watt (W) ............................................... 6.973 333 E−02 
calorie
th
per second (cal
th
/ s) ............................... watt (W) ...................................................... 4.184 E+00 
kilocalorie
th
per minute (kcal
th
/ min) .................. watt (W) ............................................... 6.973 333 E+01 
kilocalorie
th
per second (kcal
th
/ s) ....................... watt (W) ...................................................... 4.184 E+03 
ton of refrigeration (12 000 Btu
IT
/ h) .................. watt (W) ............................................... 3.516 853 E+03 
 
Specific Heat Capacity and Specific Entropy 
British thermal unit
IT 
per pound degree Fahrenheit 
[Btu
IT
/ (lb · ºF)] ............................................ joule per kilogram kelvin [J / (kg · K)] ..... 4.1868 E+03 
British thermal unit
th
per pound degree Fahrenheit 
[Btu
th
/ (lb · ºF)] ............................................ joule per kilogram kelvin [J / (kg · K)] ....... 4.184 E+03 
British thermal unit
IT
per pound degree Rankine 
[Btu
IT
/ (lb · ºR)] ........................................... joule per kilogram kelvin [J / (kg · K)] ..... 4.1868 E+03 
British thermal unit
th
per pound degree Rankine 
[Btu
th
/ (lb · ºR)] ............................................ joule per kilogram kelvin [J / (kg · K)] ....... 4.184 E+03 
calorie
IT
per gram degree Celsius 
[cal
IT
/ (g · ºC)] .............................................. joule per kilogram kelvin [J / (kg · K)] ..... 4.1868 E+03 
calorie
th
per gram degree Celsius 
[cal
th
/ (g · ºC)] .............................................. joule per kilogram kelvin [J / (kg · K)] ....... 4.184 E+03 
calorie
IT
per gram kelvin [cal
IT
/ (g · K)] ............. joule per kilogram kelvin [J / (kg · K)] ..... 4.1868 E+03 
calorie
th
per gram kelvin [cal
th
/ (g · K)] .............. joule per kilogram kelvin [J / (kg · K)] ....... 4.184 E+03