Talk:British thermal unit

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The statement "143 BTU is required to melt a pound of ice." is wrong: it depends on the temperature of the ice. It will take 10 times more BTUs to melt -10C cold ice than to melt -1C cold ice. --75.210.120.2 22:13, 24 January 2007 (UTC)

Contents 1 BTU or Btu 2 Tons of Cooling 3 UK Legal BTU 4 suggest adding in some info from 5 Switching Sections 6 North America or Global

[edit] BTU or Btu

I believe that the proper capitalization is Btu. --User:Eliasen 03:38, 13 Nov 2004 (UTC)

I learnt it as BTU. The Britannica uses BTU, as does the Webster and other sources.

Urhixidur 04:12, 2004 Dec 30 (UTC)

More reliable, in the context of appropriate symbols for units of measure, sources such as the NIST Guide for the Use of the International System of Units (SI) with its extensive list of conversion factors use "Btu". [1] Gene Nygaard 18:59, 8 Jun 2005 (UTC)

ISO 31-4 also uses "Btu". Markus Kuhn 23:48, 9 December 2005 (UTC)

"TSB-003 Rules for SAE Use of SI (Metric) Units" (revised May 1999) also uses Btu. All this proves is what the American usage is...

Urhixidur 02:56, 2005 Jun 9 (UTC)]

Sure. In the same sense that http://www.deh.gov.au/atmosphere/airtoxics/publications/report4/conversions.html "proves" that Btu is the Australian usage as well. Gene Nygaard 04:00, 9 Jun 2005 (UTC)

That page has moved to http://www.deh.gov.au/atmosphere/airquality/publications/report4/conversions.html Urhixidur 20:05, 2005 July 26 (UTC)

[edit] Tons of Cooling

In the HVAC trade, tons of cooling or ton capacity is used in addition to BTU/H. One Ton of Cooling is equal to 12,000 BTU/h. A condenser unit that can continuously cool at 12,000 BTU per hour has a 1 ton capacity.

According to Dr-Fix-It, the name comes from the fact that it takes 288,000 BTU to melt one ton of ice at 32 °F to water at 32 °F in 24 hours, which is 12,000 BTU per hour.

Source: [2]

That's something that belongs at, and is listed at, ton. Gene Nygaard 18:59, 8 Jun 2005 (UTC)

I think it does belong here with the other equivalents. Also, I added it because you can't find the common terms tons of cooling or ton capacity. It should also be in Conversion_of_units. DavidAmis 28 June 2005 15:58 (UTC)

It doesn't really have anything to do with the Btu per se, though it was standardized to a rounded number of Btu per hour. It belongs at one of the ton articles, perhaps with a see also here. It is at conversion of units already, as two different unit (one possibly apocryphal) under the name ton of refrigeration as a quantity of power, though the associated energy unit (this power times a time of 24 hours) is not there. See if you can track down anything on that other "ton of air-conditioning" as a unit of power there, that's totally unfamiliar to me. Then explain all of them the best you can in the ton article which already has some of this. Gene Nygaard 28 June 2005 16:49 (UTC)

[edit] UK Legal BTU

Weird. The 1055.05585257348 BTU doesn't explain itself (if you Google for 1.05505585257348, you get six essentially identical laconic hits). Is it a refinement of the IT BTU? The problem is that the IT BTU is not a rounded equivalent; you can't get 1055.05585262 from 1055.05585257348...

Urhixidur 19:59, 2005 July 26 (UTC)

It makes no sense to me. Bobblewik 18:55, 27 July 2005 (UTC)

It explains itself fairly well; it is the result of a poor use of conversion factors. It isn't chance that this number is equal to (453.5923698)(4.1868)/1.8. Now, to understand the 453.5923698, you only need to look to the intermediate rounding of 453.59237/1.8 to 251.995761, since that number times 1.8 is 453.5923698. Thus, 251.995761×4.1868 = 1055.05585257348, but since they only have 9 significant digits in that first number, it should have been rounded to 1.055055853 in the result.

Note that the 1995 Statutory Instrument is not the primary definition of any of the units it contains (if it were, the U.K. would have a strange definition of the hour, with those definitions of nautical miles and knots). It merely collects various definitions from other sources.

Note that you also can't get from a nautical mile defined as exactly 1,853 m to the conversion factor for knots in that list of conversion factors. Same problem, rounding. The actual definition of those nautical miles remains 6,080 feet exactly.

Since that measurement doesn't differ from the other one on the article page for the steam table Btu at a precision that have ever, anywhere, been used for any measurement made in Btu, there is no real need for the double listing on the article page. Gene Nygaard 19:35, 27 July 2005 (UTC)

[edit] suggest adding in some info from

http://ergo.human.cornell.edu/studentdownloads/DEA350notes/Thermal/thcondnotes.html

specifically "SURFACE AREA OF BODY" section. ---Fractal3 21:19, 13 April 2006 (UTC)

That has nothing to do with the Btu as such. Gene Nygaard 00:49, 14 April 2006 (UTC)

[edit] Switching Sections

Because the conversion is simpler and often all people are searching for (beside the initial definition), I suggest we switch the more detailed "Description" section with the "Conversion" one. --Theultimatejoeshmo 03:08, 23 October 2006 (UTC)

[edit] North America or Global

I've lived in the UK and currently New Zealand where BTU is used for cooling systems specifications. Should the opening sentence 'used in North America.' be expanded? —The preceding unsigned comment was added by Mikeldub (talk • contribs) 13:50, 9 January 2007 (UTC).