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Glossary

Copyright 2008-10,
CaliforniaPHOTON.com
V 1.06
site last updated: 6/26/2010

C a l i f o r n i a   P H O T O N

Energy Measurement

Although energy can exist in many different forms, it can be measured and compared along a single axis because it can be converted between forms. Measurement of the familiar forms of energy involves measuring quantities of mechanical force, weight, distance, temperature, electric charge and current, and/or time.

unit defnition equivalent units
joules kWh BTUs
SI* unit of energy joule Force of 1 newton over distance of 1 meter;
Watt second
1 2.777*10-7 9.481*10-4
Commonly unit of electrical energy kWh (kilowatt hour) Power of 1,000 watts for 1 hour 3,600,000 1 3,413
Common English units of thermal energy or fuel equivalents BTU (British Thermal Unit) Temperature increase of 1 degree Fahrenheit in 1 pound of water at 1 atmosphere 1,055 2.931*10-4 1
therm 100,000 BTUs 1.055*108 29.3 100,000
CCF (Hundred Cubic Feet) 1 hundred cubic feet of natural gas at standard pressure 103,100
GGE (Gasoline Gallon Equivalent) Energy content of 1 liquid gallon of gasoline 1.2*108 33.4 114,113
Other units of energy erg Force of 1 dyne over distance of 1 centimeter 10-7
(kilogram) calorie Temperature increase of 1 degree Celseus in 1 kilogram of water at 1 atmosphere 4.19

* The International System of Units (SI) is the modern form of the metric system and has units of measurement defined in terms of seven base units and numerous derived units. Accordingly, the Joule is a derived unit defined in terms of the base units of force (newton) and distance (meter).