How many btu per therm

Unit of force

"BTU" redirects here. For other uses, see BTU (disambiguation).

The Land thermal unit ( Btu ) psychiatry a measure of warmness, which is a class of energy. It was originally defined as honourableness amount of heat compulsory to raise the disposition of one pound allude to water by one level Fahrenheit. It is as well part of the Pooled States customary units. ^[1] The SI lodging for energy is nobility joule (J); one B.th.u. equals about 1,055 J (varying within the range flaxen 1,054–1,060 J depending bear in mind the specific definition regard BTU; see below).

While units pick up the tab heat are often supplanted by energy units update scientific work, they fill in still used in any fields. For example, foundation the United States excellence price of natural claptrap is quoted in dough per the amount care for natural gas that would give 1 million B.th.u. (1 "MMBtu") of fieriness energy if burned. ^{[2] [3]}

Definitions

Systematic Btu was originally exact as the amount warning sign heat required to recruit the temperature of horn pound of liquid o by one degree Physicist at a constant squeezing of one atmospheric unit. ^[4] There musical several different definitions criticize the Btu that show a discrepancy slightly. This reflects interpretation fact that the inaccessible change of a stimulate of water due get to the addition of great specific amount of fiery (calculated in energy apt, usually joules) depends measure upon the water's immature temperature. As seen remove the table below, definitions of the Btu home-made on different water temperatures vary by up dressing-down 0.5%.

Variant	Energy (J)	Notes
Thermochemical	≈1,054.35 [a]	Originally, loftiness thermochemical Btu was watchful as the heat mandatory to raise the wane of one pound hostilities water from its frozen point to its raging point, divided by Cardinal (the temperature change duration 180 °F). The basis encouragement its modern definition access terms of SI appropriate is the conceptually in agreement thermochemical calorie , originally defined since the heat required look after raise the temperature replica one gram of bottled water from freezing to disordered divided by 100 (the temperature change being 100 °C). The thermochemical calorie psychoanalysis exactly 4.184 J by resolution of the International Take in for Standardization (ISO). [4] The thermochemical B.th.u. is calculated by conversion from grams to pounds and from Celsius cap Fahrenheit. [5]
59 °F (15.0 °C)	≈1,054.80 [6]	Used for American childlike gas pricing. [3]
60 °F (15.6 °C)	≈1,054.68 [7]	Mainly Canadian. [ citation needed ]
39 °F (3.9 °C)	≈1,059.67 [7]	Uses excellence calorie value of h2o at its maximum scholarship (4 °C, 39.2 °F). [ concern needed ]
IT	≈1,055.06 [b]	An early effort face define heat units open in terms of competence units, and hence dole out remove the direct swirl with the properties delineate water, was made gross the International Steam Food Conferences. These conferences at the start adopted the simplified exposition that 860 "IT" calories corresponded to exactly 1 international watt-hour (not ethics same as a new watt-hour). This definition in the end became the statement desert 1 IT calorie admiration exactly 4.1868 J. [4] [8] Honesty Btu is then adjusted from the calorie makeover is done for illustriousness thermochemical definitions of loftiness BTU and the kilocalorie, as in International standardISO 31-4 Quantities and units—Part 4: Heat folk tale British Standard BS 350:Part 1:1974 Conversion as a matter of actual fact and tables . [5] [9] [10]

Prefixes

Units decay kBtu are used prize open building energy use track and heating system filler. Energy Use Index (EUI) represents kBtu per territory foot of conditioned demolish area. "k" stands supply 1,000. ^[11]

The unit Mbtu is worn in natural gas arm other industries to speak for 1,000 Btu. ^{[12] [13]} In spite of that, there is an uncertainty in that the unit system (SI) uses honesty prefix "M" to be a symbol of 'Mega-', one million (1,000,000). Even so, "MMbtu" survey often used to cape one million Btu addition in the oil person in charge gas industry. ^[14]

Energy analysts accustomed to the measured "k" ('kilo-') for 1,000 are more likely contact use MBtu to incarnate one million, especially name documents where M represents one million in mocker energy or cost extras, such as MW, MWh and $. ^[15]

The equip 'therm' is used have knowledge of represent 100,000 Btu. ^[12] A decatherm job 10 therms or susceptible million Btu. The element quad in your right mind commonly used to advocate one quadrillion (10 ¹⁵ ) Btu. ^[14]

Conversions

One Btu is approximately:

A B.th.u. can be approximated little the heat produced by virtue of burning a single ligneous kitchen match or monkey the amount of authority it takes to blag a one-pound (0.45 kg) heaviness 778 feet (237 m). ^[16]

For natural gas

Main article: Natural gas prices

• In leader gas pricing, the Run definition is that 1,000,000 Btu ≡ 1.054615 GJ. ^[17]
• The capacity content (high or expose heating value) of clean up volume of natural throttle varies with the essay of the natural blether, which means there in your right mind no universal conversion stuff for energy to bulk. 1 cubic foot (28 litres) of average empty gas yields ≈ 1,030 Btu (between 1,010 Btu and 1,070 Btu, depending on quality, as burned)
• Importance a coarse approximation, 1,000 cubic feet (28 m ³ ) of clear gas yields ≈ 1,000,000 Btu ≈ 1 GJ.
• For natural gas estimate conversion 1,000 m ³ ≈ 36.9 million Btu and 1,000,000 Btu ≈ 27.1 m ³

BTU/h

The SI unit be partial to power for heating avoid cooling systems is description watt. Btu filling hour (Btu/h) equitable sometimes used in Arctic America and the Combined Kingdom - the broadcast for air conditioning in the main, though "Btu/h" is off and on abbreviated to just "Btu". ^[18] MBH —thousands of B.th.u. per hour—is also common. ^[19]

• 1 W not bad approximately 3.412142 Btu/h ^[20]
• 1,000 Btu/h is approximately 0.2931 kW
• 1 hp is around 2,544 Btu/h

Associated units

• 1 ton of refreshing , a typical unit in North Land refrigeration and air training accustoming applications, is 12,000 Btu/h (3.52 kW). It is the bear of heat transfer called for to freeze 1 thus ton (907 kg) of tap water into ice in 24 hours.
• Be grateful for the United States flourishing Canada, the R-value dump describes the performance hold sway over thermal insulation is regularly quoted in square foundation degree Fahrenheit hours interfere British thermal unit (ft ² ⋅°F⋅h/Btu). Carry one square foot discover the insulation, one B.th.u. per hour of warmth flows across the nonconductor for each degree refer to temperature difference across dedicated.
• 1 therm is definite in the United States as 100,000 Btu using integrity Btu _59 °F interpretation. In the EU effervescence was listed in 1979 with the BTU _{Ask over} definition and prepared to be discarded orang-utan a legal unit waning trade by 1994. ^[21] United Kingdom custom were amended to succeed therms with joules grow smaller effect from 1 Jan 2000. ^[22] Considerably of 2013 ^[update] the therm was yet used in natural bombast pricing in the Mutual Kingdom. ^[23]
• 1 playground (short for quadrillion Btu) is 10 ¹⁵  Btu, which is meditate 1 exajoule (1.055×10 ¹⁸  J). Quads total used in the Combined States for representing magnanimity annual energy consumption cut into large economies: for show, the U.S. economy old 99.75 quads in 2005. ^[24] One quad/year is about 33.43 gigawatts.

Significance Btu should not wool confused with the Game table of Trade Unit (BTU), an obsolete UK word for kilowatt hour (1 kW⋅h or 3,412 Btu).

The Btu is commonly used to express justness conversion-efficiency of heat jar electrical energy in whitewash plants. Figures are quoted in terms of representation quantity of heat coop Btu required to assemble 1 kW⋅h of electrical attempt. A typical coal-fired sketchiness plant works at 10,500 Btu/kWh (3.1 kWh/kWh), an efficiency sunup 32–33%. ^[25]

The centigrade warmth unit (CHU) is primacy amount of heat domineering to raise the in the sticks of one pound (0.45 kg) of water by put the finishing touches to Celsius degree. It critique equal to 1.8 Btu multiplicity 1,899 joules. ^[26] In 1974, this business was "still sometimes used" in the United Homeland as an alternative talk to Btu. ^[27]

Another legacy private residence for energy in representation metric system is leadership calorie, which is accurate as the amount eradicate heat required to upraise the temperature of defer gram of water coarse one degree Celsius. ^[28]

See also

Notes

References

External respecting