Talk:Liquid nitrogen economy

Validation needed
It's not good Wikipedia form to cite your own website as an external link. There's no analysis of the practicalities of the proposed system. What is "L2N" supposed to mean, anyway? This article is seriously flawed until it gets some facts, not just hypothesizing. --Wtshymanski 04:32, 18 July 2005 (UTC)

Some figures
According to this paper http://www.phys.unt.edu/~cordonez/IMECE01.pdf

The ideal (Carnot) specific work available by using the heat of vaporisation of liquid nitrogen is given by w =L[(Th/Tc )-1]
 * For liquid nitrogen L, the heat of vaporisation is 200kJ/Kg
 * The boiling point of liquid nitrogen is 77Kelvin
 * The temperature of atmospheric air is ~ 300Kelvin

And this gives 570 kilojoules of energy per kg of Liquid nitrogen Lumos3 15:47, 18 July 2005 (UTC)
 * Yep, and the energy density of gasoline is 45,000 kJ/kg. Do you see the crack-pottery aspect? Plus you've come up with a higher number than I've seen elsewhere which I suspect is faulty; how can you  *more* than the heat of vaporization out of each kg ( you seem to have Th and Tc interchanged)? ...though it doesn't seriously affect the plausibility. And why hasn't the proponenent done even high-school-level maths calculations in his web site? --Wtshymanski 17:02, 18 July 2005 (UTC)


 * Your approach is analytical. However you do seem to grapple disparate approaches, valid enough, you are among good company. Drop the emotive comments.


 * Like any engineer I need time! A solution needs to be complete and compatible, as does your critique. The Carnot engine is a steady state, reversible engine. Why have you just proved the Carnot engine does not achieve the temperature dependant efficiency required of a reversible Carnot engine? Pete

The article you have just quoted is supportive of the exploration liquid nitrogen and heat sink for a Stirling engine or Carnot equivalent. My initial thought, is that you have proved the steam engine is not about to return in force. I view that I share! Pete
 * See No original research. I am unable to find even on the Web any other public discussion of a "liquid nitrogen economy", aside from what appears to be your very own web site. Please cite some other publication that discusses the ramifications of a "liquid nitrogen economy". Your writing style is more than a little opaque and perhaps I'm having trouble understanding you. Please explain to me how making liquid nitrogen at 0.45 kwh/kg and then using in propulsion at a yield never better than 0.055 kwh/kg makes any economic sense or reduces CO2 emissions. An engineering proposal generally is worked out in some numerical detail before it hits public view. Please sign your comments with date and time, using either four tildes in a row ( --~ ) or else the button at the top of the editing window (if you're using Wikipedia's own editor). --Wtshymanski 20:31, 18 July 2005 (UTC)


 * Regarding Lumos3's energy calculations, are you simply measuring the thermal difference? I'd heard about some engines that used the expansion of compressed (or liquified) gases, essentially updated steam engines. Pneumatic engines have a long history of use. I'm not an engineer so I don't know how the force generated by expansion can be calculated. Cheers, -Willmcw 21:59, July 18, 2005 (UTC)


 * The two university research projects listed, though they do not use the exact phrase Liquid Nitrogen economy, show that the idea of using LN as a means of storing energy has been and is on the energy agenda and it deserves a mention on Wikipedia. The phrase itself is not out of place amongst the alternative approaches like Hydrogen economy and ethanol economy. Lumos3 09:39, 19 July 2005 (UTC)
 * I must disagree. No-one else in the world is seriously considering liquid nitrogen as a substitute for petroleum. Yes, you can propel a golf cart across the campus boiling off liquid nitrogen, just as you can get down a hill on a concrete toboggan; but it's not relevant in the slightest to the general problems of energy and environmental issues. The very problems with hydrogen and ethanol are the low density of energy storage, cryogenic liquid handling (for H2, anyway, in some cases) and the poor level of energy returned at use to energy input in manufacture. You could probably run a car on enough D size flashlight batteries, but no-on is proposing *that* as a solution either.  I plan to nominate this article for VfD. --Wtshymanski 14:34, 19 July 2005 (UTC)


 * I'm not sure what VfD is but it sounds fatal. Would you find the page less offensive with a different name?  Pulling together a sound article that fits well with other well crafted pages takes time.  How about a move to entertaining cryogenic energy usage, Another concrete sledge or Cryogenic energy storage.


 * Take a look at the limitations section and let me know what you think? Add to it as you see fit. --Pete 20:06, 19 July 2005 (UTC)


 * Impracticality is not a criteria for deletion. As long as we use verifiable sources and treat the issue in an NPOIV manner, there is no reason to delete the article. -Willmcw 20:40, July 19, 2005 (UTC)
 * True, there's a lot of impractical things on Wikipedia but they are *identified* as such. The article, as such, discusses something that coesn't exist and so is not a fit subject for an encyclopeida article; this article is in serious danger of *becoming" the only public discussion of its nominal subject. "Cryogenic vehicle propulsion" would be a better place to put the contents, less grandiose than "Liquid Nitrogen Economy".  --Wtshymanski 21:25, 19 July 2005 (UTC)


 * The hydrogen economy does not exist either, nor does the Freedom Tower, yet we have NPOV, sourced articles that properly describe the plans, designs, and problems for those things which may become reality. I think the propulsion suggestion may be too limited, as liquid Nitrogen can also be used for cooling, etc. -Willmcw 22:09, July 19, 2005 (UTC)


 * Wtshymanski Nice edits. Well reasoned. --Pete 18:16, 21 July 2005 (UTC)

Research
This article is intended to be a summary of research, of which there is plenty. Please refrain from expressing your empire building plans.--Pete 19:03, 15 August 2005 (UTC)

(Pete deleted the whole discussion and replaced it with the above statement. Please dont delete a discussion page its seen as very bad behavior in WikiP Lumos3)

Avoiding an edit war
I can see this article getting into a close edit war with every statement in favour being balanced by a qualifying one against. This benefits nobody as the article becomes unreadable. The way out of this is to have the argument for clearly set out and then section(s) arguing against. Please keep for and against arguments within the two areas and refrain from mixing them point by point. Lumos3 21:18, 15 August 2005 (UTC)
 * The article suffers from the deficiency of not addressing the energy cost of manufacture of liquid nitrogen in the first place. There was text in an earlier revision which I see has been removed that spoke of this problem. The achievable (not Carnot) efficiencies of practical crygen engines have not been tabulated. The SAE paper by Knowlen et al, cited as Reference 1, does not address these points. The article talks about Stirling engines but Reference 1 does not, and seems to be using the nitrogen gas as a working fluid in an expander - this is not a Stirling cycle. The paper does not give a value for "comparable" range - using the figures in the article and 15 kW as typical road power consumption on flat ground at steady 80 km/h, I get a range of about 130 km for the 350 l tank, (20 HP for a light SUV at 50 MPH = 14.9 kW at steady 80 km/h, 70 WH/l *350 L = 24.5 kWH, 24.6/14.9=1.6hrs * 80 = 132 km)  which would be about 1/4 the range one would expect of a gasoline powerered car (and of course much less due to start/stop traffic and the less than Carnot efficiency any practical engine would have).  The paper should perhaps have said "range comparable to a primitive electric car". The 350 litre capacity cited does not yield near as much energy as a 50 litre tank of gasoline, and 3600 litres would be more accurate.  --Wtshymanski 21:51, 15 August 2005 (UTC)
 * While performing our own calculations may be interesting, and serve as a check on references, please remember that actually adding any editor-dereived figures to the article would be original research. Thkans, -Willmcw 22:00, August 15, 2005 (UTC)
 * Well, yes - but multiplying a few numbers is hardly original. In any case that's why the ciphering is here...the referenced paper seems to have a degree of bogosity about it.  Time to nomitate for VfD, I think. --Wtshymanski 00:03, 16 August 2005 (UTC)


 * Any original research, which includes deciding which numbers to plug into an equation, is not worth including. Which paper has bogosity and on what basis do you make that assertion? Thanks, -Willmcw 00:15, August 16, 2005 (UTC)
 * The paper cited in today's version of the article as "Ref. 1", the SAE paper by Knowlen, et. al. - as I referred to at the start of my earlier response today. --Wtshymanski 00:24, 16 August 2005 (UTC)


 * That paper mentions some interesting conclusions. Comparing the use of liquid Nitrogen as a storage medium to lead-acid batteries they find it has a significantly higher specific energy content. They give an estimate of the energy cost, one of your issues, (~0.5 kW-hr/kg-LN2). They discuss the use of a Rankine engine rather than a Stirling engine. 132 km is not far from the range of most electric cars, IIFC. Again, the valid comparison is to batteries, Hydrogen, or other storage medium, not gasoline. If we had gasoline at $.50 a gallon forever then no one would care about these exotic technologies. Finally, this paper seems to have been paid for by the DOE so it has some respectability. It's not just some inventor looking for investors. If you want to apply some hard-nosed editing to an engineering article then I wish you'd take a look at quasiturbine. Bogosity? -Willmcw 06:16, August 16, 2005 (UTC)

One meter cube of liquid N2 = 320 miles ?
The research vehicle used a preheater.

For the Stirling use a precooler.

(Stirling H2 is cooled by N2 exhaust gas before it reaches the N2 liquid

Summary of Nitrogen properties:

http://www.uigi.com/nitrogen.html

.808(199.1+195.8x1.04) = 325.4 Kj per liter

divide by 3600 = .09 KWH/liter or 90 KWH per cubic meter

Total cost per liter to liquefy is $0.22 = $220 per m^3

http://www.rigakumsc.com/cryo/nitrogen.html

Say 80% efficiency and 4 miles per KWH = 320 miles

Incorrect since heat capacity is proportional to °K Need to integrate from boiling to ambient.

Efficiency questions
What is the efficiency of creating a kilowatt of LN2, storing it safely for an hour, and then converting it back to energy at STP? What is the volume of 1 kw of LN2

What is the loss per mile of pipeline?

Liquid Nitrogen Economy: throwing in another factor.
Thanks to all for the interesting discussion on Liquid Nitrogen, it seems it has some efficiency or power density issues. But I'm not solving vehicle power here. Let me introduce a problem from another field: How to store energy generated by wind turbines.

I'm just thinking about base load for the electricity grid. When the wind blows, create lot of LN (or even liquid air) as efficently as you reasonably can, and store it in large insulated tanks. When the wind stops, use the LN to run stirling engines to geneate power.

The size of the tanks is big enough that NH losses due to warming up are small over say a 3 week period while the wind doen't blow (Such a long period is very rare.)

Thank you for opening this discussion. The logic for the use of liquid nitrogen as an energy transfer medium is primarily political, time will tell if the economics make sense.

1. It may be the demand for air conditioning that will push the world into an energy and global warming crisis. 2. Emerging nations will demand air conditioning next in their development. Can you imagine how much energy it would take to provide air conditioning to homes and workplaces in India whose middle class is larger than the population of the US? 3. How is it possible to provide air conditioning without use of fossil fuels and, better, without generating waste heat (which also would need to be removed from the building)? 4. The answer is to use the energy in its final form. Liquid nitrogen is liquid coldness. How can liquid nitrogen be created without the use of fossil fuels? The answer is remotely, where free renewable power is available. There are many orphan sites which have no grid to connect to, offshore Canadian Islands, and Iceland, for instance. 5. I imagine a future day when a tanker of liquid nitrogen enters New York harbor in June, having harvested a winter's produce of liquid nitrogen from windfarms in Labrador. The tanker fills thermal reservoirs where chillers used to sit in the basements of office towers. A simple heat exchanger takes the place of the old chiller and attaches directly to the existing chilled water lines. 6. Yes, liquid nitrogen may not be an efficient way to store energy, but consider the inefficiency of conventional cooling: Coal is transported, burned, water is boiled, turbines are spun, electricity is generated and, then, re-converted to mechanical rotation, and a coolant is compressed and reexpanded. Chemical energy is converted to mechanical, to electrical back to mechanical back to phase change. If all of the conversion energy losses in the conventional cycle are added up they may exceed the carnot inefficiency of creating and then vaporizing nitrogen. I cannot do the math but, when the whole picture is looked at, there is some engineering logic to this idea. 7. The economic logic is a) green cooling will sell at a premium in the future and b) on a hot humid day in Manhattan, in the midst of a brown-out, having stored coolness in the basement of your building would be priceless.

-Great idea, BUT, what is the actual cooling capacity of 1 kg of liquid air? 195(Celsius)* 1000(gram)=195,000 cal or 195 kcal when 1 ton of refrigeration is equal to 3011 kcal...

so, 1 kg of liquid air is actually 0.064 TR. mmmm if this calculation is any close to the correct one (is it?), that really not effective.

Comments by Mechanical engineers are welcome K casbel 08:27, 20 January 2007 (UTC)
 * If you cannot do the math, you have no base to assert there's any "engineering logic" to this Rube Goldberg or Heath Robinson concept. --Wtshymanski 16:17, 20 January 2007 (UTC)

Sorry!
I was trying to split this off as another discussion. Ooops.

Petroleum
There appears to be a POV in this article that petroleum is better. I don't see any sources to say so, but more importantly it's an incorrect comparison. No one is proposing that any alternative energy form is better than petroleum in all respects. If we're going to compare LNE to other topics then hydrogen fuel cells, electric batteries, etc. are the correct comparisons. ·:· Will Beback ·:· 22:03, 13 November 2007 (UTC)
 * There's point of view and then there's the laws of physics. A jerry can full of gasoline will run a very comfortable automobile at high speeds for hundreds of kilometers, whereas the same volume of liquid nitrogen, vaporized in some grad student's nightmare of Stirling engines and multiple heat exchangers, will propel a glorified golf cart no more than once around the course. There *is* no liquid nitrogen economy, it's a Wiki fiction, and the promoters of this badly conceived notion won't do the math to understand *why* this concept can't work. I, as an aged and cynical engineering type, understand why of the last 10,000 vehicles to pass by my office today, none of them were propelled by vaporizing nitrogen. But the proverbial bright 12-year-old user of Wikipedia MUST be informed that there's a severe issue with the horrendous energy cost of liquifying the stuff in ton lots in the first place. Also, every "...economy" or "...as energy currency" article must distinguish between a primary energy source like oil, and media useful only for transmission (like hydrogen, and the various further-out proposals here in the Wikipedia). It's not POV, it's physics. This article should have been deleted years ago. --Wtshymanski 22:35, 13 November 2007 (UTC)
 * A jerry can full of plutonium carries even more energy. So? This article isn't about plutonium or petroleum. The competitors to liquid nitrogem as an energy storage medium aren't plutonium or petroleum or coal. They are batteries, hydrogen gas, and a few others. ·:· Will Beback  ·:· 23:33, 13 November 2007 (UTC)
 * This article would be much better if contributors understood why we don't have jerry cans full of liquid nitrogen or plutonium to fuel cars. --Wtshymanski 00:04, 15 November 2007 (UTC)
 * We presently carry lead-lined boxes full of acid to provide energy for cars. There are proposals to carry liquid hydrogen, compressed air, or molten sodium to fill the same role. Those are all energy storage media that convert electricity into a form that can be carried and released gradually. Petroleum is not an energy storage medium. We either drill for it or convert coal into it. Once it is uneconomical to obtain, or the carbon concerns make it unwise to use in large quantities, technologies that store cleanly-created electricity will become more and more important. The current cost of building a hydrogen fuel cell car is around $1 million, so other despite the endorsement of President Bush other techniques remain potentially competitive. Liquid nitrogen one of those techniques. It is easier to create and safer than liquid hydrogen. The purpose of this article is to provide a neutral summary of the current engineering and economic status of as an energy storage medium, not to show the advantages of using petroleum over an energy storage medium. ·:· Will Beback  ·:· 00:49, 15 November 2007 (UTC)
 * And of the last 10,000 cars to pass by my window, none of them were propelled by batteries, either. Why is this so? And what are the reasons that liquid nitrogen will never become economically important as an energy storage medium? Petroleum is important precisely because it is not only a primary energy source but because it can be processed, piped, shipped, and stored with low losses. The present liquid nitrogen article is quite uninformative about the energy losses in each step of the proposed cycle. Until this article faces up to the engineering limitations of boiling cryogenic liquids as energy storage means, it is nothing but pseduoscience. --Wtshymanski 15:00, 15 November 2007 (UTC)
 * Do you think that in 100 years every car is still going to be powered by petroleum? It's possible, but the assumption of scientists and policy makers appears to be that petroleum will be in short supply and that global warming will severely constrain the use of hydrocarbons in combustion. Of course petroleum is better than hydrogen, batteries, or LN in many respects. Whale oil had many advantages as a fuel too, but even so we stopped using it for lighting a hundred years ago when whales became scarce and another fuel became plentiful. Is LN competitive and practical now compared to petroleum? Of course not. Is fusion a competitive and practical source of electricity? Nope, but even so scientists and policy makers invest billions of dollars and thouaands of man-hours on it, and Wikipedia has many articles on the topic. To get back to the point of this thread: huydrogen, LN, and other technologies aren't competitive with petroleum while gasoline sells for $3 or even $10 a gallon. But when gasoline sells for $20, $40, or $100 a gallon then the picture will be different. If a full tank of LN costs $5 and goes 30 miles in a vehicle costing $30,000 that may be competitive with a hydrogen-fuelled vehicle that has twice the range but costs $300,000, and would certainly be competitive with a gasoline-powered vehicle that costs $25,000 to buy but takes $100 worth of fuel to go 30 miles. Or do you believe that petroleum will last forever and that there will never be limits on carbon emissions? ·:· Will Beback  ·:· 19:33, 15 November 2007 (UTC)
 * Not the point. As is typical for this article, there's more analysis and thought in the talk page than is represented in the article itself. If you look at the edit history you find the original major contributor never did address any physical limitations to the scheme; basically the originator ran away with a couple of papers about a grad-student stunt for propelling a vehicle and in a stunning and un-Wikipedia like burst of original research, extrapolated this stunt to a whole world using vaporizing N2 for energy conversion. --Wtshymanski (talk) 01:42, 18 November 2007 (UTC)

Political Argument section
I have removed this section which reads like confused waffle. It does not even mention the subject of the article. Please redraft if you want it included. Lumos3 (talk) 12:23, 30 December 2007 (UTC)

The way to utilize liquid N2 or air is in conjunction with combustion or solar heat addition. It is after-all an engine coolant; liquid air also being an oxidizer. It will lower compression work in a gas turbine, thus increasing tank to shaft efficiency to the 70 - 80 % range. There are many sources of renewable energy to drive liquefiers and the current interest in liquefied natural gas is leading to improved liquefier technology. The math has been done. See: http://liquidaireconomy.blogspot.com/ lqairecon — Preceding unsigned comment added by Lqairecon (talk • contribs) 13:01, 19 June 2012 (UTC)