Talk:Liquid hydrogen

message: The current article is at an abbreviation and the full name, liquid hydrogen, is a redirect to it. They should be switched. -- Kjkolb 09:32, 27 November 2005 (UTC)
thread_title:  Requested move 

message: After a brief google search I found two articles that would be useful sources.  
The first is on the different liquification processes: http://www.enaa.or.jp/WE-NET/ronbun/1997/e5/sanso1997.html
The other is on the significance between ortho and para hydrogen: http://www.cchem.com/opcat/index.html
Unfortunately I am short of time right now or I would incorporate the material andperhaps track down the references for the material that is already here. I am against merging this article with the Hydrogen article because I think there is enough material out there to make this a solid stand alone article.  For a start, there needs to be sections for properties, history, applications, production methods, references. Badocter 05:26, 16 September 2006 (UTC)
thread_title: Material to expand material article with

message: The last sentence of the "drawbacks" section says that "The advantage remains, however, that pollution is decentralised to the hydrogen production facilities and power plants and for example, therefore kept away from centres of population.".  However, wouldn't the pollution be centralized to the hydrogen power plants, as it is not the cars, but the productions facilities that would be emitting pollution?  Any thoughts? 71.227.195.32 (talk) 21:38, 8 December 2008 (UTC)
thread_title:  Mistake? 

message: Hydrogen burns with a very high flame temperature but which emits light which is nearly invisible to the naked eye and is a safety hazard. Typical piston engines burning hydrogen in ambient air (not simply oxygen) produce high amounts of NOx pollution.
The fact that the byproducts of combustion are mainly water is commonly used as an argument that the use of hydrogen as a fuel is not harmful to the environment, however this does not take account of the energy intensive methods required to produce, compress/liquefy and store it. In thermodynamic terms, as these methods can never be perfectly efficient, until a ready source of hydrogen is identified, its use as a fuel should be considered more harmful to the environment than most fossil fuels.  The advantage remains, however, that pollution is decentralised to the hydrogen production facilities and power plants and for example, therefore kept away from centres of population.
:Both sections are not about liquid hydrogen. Mion (talk) 06:36, 2 January 2009 (UTC)
thread_title:  moved from article 

message: "The byproduct of its combustion with oxygen alone is water vapor. Since water is considered harmless to the environment, the engine is considered "zero emissions.""
: Water vapor is potent because there's so much of it. Compare its 2 % to about 0,035 % of CO2. It also disappears rather quickly. The only way we humans are going to drastically change the amount of water vapor, is by warming the atmosphere with more long-lived greenhouse gases, thereby increasing the amount of vapor the air can hold. --85.224.87.248 (talk) 18:03, 8 February 2011 (UTC)
thread_title:  Water vapor is a greenhouse gas far more potent than CO2. 

message: Both of these section seem out of place because they deal with liquid hydrogen in cars and vehicles. However liquid hydrogen is a form of an element. It seems much more important to highlight the safety concerns or storage techniques. Drawbacks and Advantages implies a specific use and i believe that discussion should be left for another article.  —Preceding unsigned comment added by 174.115.174.3 (talk) 22:24, 5 November 2010 (UTC)
thread_title:  Is Advantages & Drawbacks relevant 

message: It seems that  Ref 6 is broken
maybe of interest http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19950016832_1995116832.pdf  ?? 
Best CoolEsza (talk) 17:47, 8 January 2013 (UTC)
replies: text: ref 6 is repaired. Mion (talk) 23:57, 1 December 2013 (UTC)
thread_title:  Ref 6 broken 

message: "Once liquefied, it (liquid hydrogen)can be maintained as a liquid in pressurized and thermally insulated containers." This is incorrect unless the container is refrigerated magnetically or with liquid He. If it is not refrigerated continuously or the ambient equilibrium temperature is not below the boiling point of the liquid hydrogen, then the hydrogen will absorb heat and boil. There is no free ride. Insulated containers alone can slow the boil-off, but not eliminate it.Magneticlifeform (talk) 06:00, 30 August 2013 (UTC)
replies: text: your answer is already in the article "Even with thermally insulated containers it is difficult to keep such a low temperature, and the hydrogen will gradually leak away (typically at a rate of 1% per day)" just keep on reading, the lead is just a short intro. Mion (talk) 00:10, 2 December 2013 (UTC)
thread_title:  Insulated containers will not prevent liquid hydrogen boil-off without refrigeration 

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