Definition: British thermal unit

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British thermal unit

The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit; often used as a unit of measure for the energy content of fuels.[1][2]

Wikipedia Definition

The British thermal unit (BTU or Btu) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit. One four-inch wooden kitchen match consumed completely generates approximately 1 BTU. In science and engineering, the joule, the SI unit of energy, has largely replaced the BTU.The BTU/h is most often used as a measure of power in the electric power, steam generation, heating, and air conditioning industries. It is still used in some metric English-speaking countries (such as Canada, but notably not the United Kingdom). In North America, the heat value (energy content) of fuels is often expressed in BTUs.The notation kBtu or KBTU is often used for thousand BTU, in sizing of heating systems and in the Energy Use Index (EUI) expressed as thousand BTU annual energy use per square foot of building. MBTU represents one million Btu, although the atypical notation MMBtu or mmBtu is sometimes used to represent one million BTU.(see definitions below), The British thermal unit (Btu or BTU) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit. One four-inch wooden kitchen match consumed completely generates approximately 1 Btu. In science and engineering, the joule, the SI unit of energy, has largely replaced the Btu.The Btu/h is most often used as a measure of power in the electric power, steam generation, heating, and air conditioning industries. It is still used in some metric English-speaking countries (such as Canada, but notably not the United Kingdom). In North America, the heat value (energy content) of fuels is often expressed in Btus.The notation kBtu or KBtu is often used for thousand Btu, in sizing of heating systems and in the Energy Use Index (EUI) expressed as thousand Btu annual energy use per square foot of building. MBtu represents one million Btu, although the atypical notation MMBtu or mmBtu is sometimes used to represent one million Btu.(see definitions below), The British thermal unit (Btu or BTU) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit. One four-inch wooden kitchen match consumed completely generates approximately 1 Btu. In science and engineering, the joule, the SI unit of energy, has largely replaced the Btu.The Btu/h is most often used as a measure of power in the electric power, steam generation, heating, and air conditioning industries. It is still used in some metric English-speaking countries. In North America, the heat value (energy content) of fuels is often expressed in Btus.The notation kBtu or KBtu is often used for thousand Btu, in sizing of heating systems and in the Energy Use Index (EUI) expressed as thousand Btu annual energy use per square foot of building. MBtu represents one million Btu, although the atypical notation MMBtu or mmBtu is sometimes used to represent one million Btu.(see definitions below), The British thermal unit (Btu or BTU) is a traditional unit of heat; it is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is part of the British Imperial system of units. Its counterpart in the metric (SI) system is the calorie, which is defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius. Heat is now known to be equivalent to energy, for which the metric unit is the joule; one BTU is about 1055 joules. While units of heat are often supplanted by energy units in scientific work, they are still important in many fields. As examples, in the United States the price of natural gas is quoted in dollars per million BTUs. Chemical bond energies are often given in calories per mole of substance.


Also Known As
Btu
Related Terms
Energyheat
References
  1. http://www.eia.gov/tools/glossary/index.cfm?id=B
  2. http://needtoknow.nas.edu/energy/glossary/