Btu
One BTU is the energy required to heat 1 avoirdupois pound of liquid water by 1 degree Fahrenheit, at a pressure of one atmosphere.
One BTU is the energy required to heat 1 avoirdupois pound of liquid water by 1 degree Fahrenheit, at a pressure of one atmosphere.
The thermochemical calorie was defined in 1930 by Frederick Rossini as 4.1833 joules. The change to absolute electrical units in 1948 involved redefining the thermochemical calorie as 4.184 joules (in order to keep the same quantity of energy represented by it). The thermochemical kilogram calorie is equal to 1,000 times that value - 4,184 J.