Electric cars are a pipe dream

[adoucette]

Yes I linked to a photo of a multi-cellular flat tank to show that contrary to statement it could not be build, it was for sale.

NOT FOR CNG

It is true than most current buyers would use propane in it,

NO, ALL buyers must use propane in it, that's what it is designed for.

but a few are already using flat tanks operating at only 500psi to fuel their cars and trucks with good travel range as the Natural Gas fuel (not propane) in their tanks is adsorbed as a liquid on the surface of baked corn cobs pressed into "hockey puck."

This system has been under design for over 6 years

http://www.ngvglobal.com/adsorbed-natural-gas-progress-0529

But it is not yet in any commercial vehicles as there are many issues in making the filler and putting it in the tank, keeping the filler working even with normal residuals found in NG (water, a common contaminant is particularly hard to desorb), and it's not about amount of gas adsorbed, but about the amount delivered (which currently appears to be ~30% less by volume than standard CNG tanks) and there are still issues with the thermodynamics of filling ANG systems in an automotive use and so it has not been released as part of consumer ready system, so your statement is somewhat misleading.

http://www.columbiatribune.com/news/2010/aug/16/mu-tries-again-with-corncob-idea/?news

And more importantly we weren't discussing ANG technology or the lower pressure tanks that can be used when/if they become a practical/economical replacement for CNG. Clearly once one is dealing with only 500 psi the tank shape is far less of an issue.

Indeed, from all I've read about ANG tanks is that with the filler they are more expensive than CNG. The savings comes from not requiring compression to 3,600 psi, but even then savings are not that much, but the tank volume required, at low pressure is still much greater than CNG and there are apparently thermal issues with filling/delivering that remain problematical as high summer temperatures, as in our South and West, could limit ability to fill these tanks nearly as full as one could do up North.

The point Billy, if had you said 100 posts or so ago that you were designing a rectangular profile ANG tank to operate at 500 psi the discussion would have been VERY different. All the posts you are complaining about came prior to you bringing up ANG.

I have been careful, as I am speaking about the future, not current technology, to NEVER SPECIFY AT WHAT PRESSURE THE TANK WILL USE.

All of my posts only compute the efficiency of the multi-cellurlar flat tank vs that of the isolated (singular cell) circular tank most current technology uses.

And yet all of the issues raised with you by myself, Trippy and Billvon have been about ability to contain the high PRESSURE required for CNG since that was what was being discussed.

Arthur

 

[billvon]

If you tell me what I have said to adoucette which is insulting and the post it is in, I will retract it and apologize.

". . .that is another of your fabricated lies about me. . . . many examples of this dishonest policy of yours, many will be examples where you have done that to others in other threads, and ask James R if he agrees that for that and your many personnel attacks you don't need a cooling off holiday from posting activity. . . . your repeated dishonesty and personnel attacks . ."

You've made mistakes. So has he. Why can't both of you just move on?

 

[adoucette]

Perhaps a picture will help you understand as you will not follow the math:

C . . [[[[[[[[[[[[[[[[[[ . . D - a cross section thru the central part of a compound tank showing all cells except one, which is “D-shaped” have only 3 sides. Note 100 cells have only 99 “tension webs” dividing them - why only one edge requires a “D-shaped” cell. The other edge cell is half of a cylindrical tank so is just as efficient as the isolated cylindrical tank is. All of the “3-sided”cells are MORE efficient especially since the webs are flat with the same pressure on both side and do not need to resist horizontal expansion (only vertical expansion caused by the relatively small force acting on the small top and bottom ends of each cell) but the walls of a cylindrical tank must resist expansion in ALL directions.

SUMMARY: Please stop falsely asserting that the flat tank, with compound-cells, is less efficient than the isolated circular tank such as here:
“
Originally Posted by adoucette
{post 2176 in part} …The fact is that rectangular tubes for the same wall thickness hold AT BEST 1/20th of the pressure. ...Arthur
”
The rest of post 2176, like dozens of adouccette’s other posts, goes on to show that for isolated single-cell tanks a circular cross section is best, and I of course agree, but I post about a multi-cellular compound tanks, so almost all of adouccette’s posts are totally irrelevant and false when extended to the compound tank, as I have repeatedly pointed out to him.

NOPE.

(And unfortunately that diagram you posted indicates you have gone back to the refuted flat tops????)

After Trippy pointed out to you that the FLAT top of your many small rectangular tanks wouldn't work you finally morphed your design to a bunch of TUBES, not rectangles as you had been asserting up until that point:

Long story short, essentially, as well as resisting the outwards force of the gas, a square tank has to resist being deformed into a circle, where as a circular tank only has to resist the outwards force of the gas.
”

I have already suggested that the two extreme edges of a flat 102 tube tank may need to "bow outward" and you do have a point that so do the top and bottom of each tube.

OK -lets go to the 3:1 rectangular cross section tube and the extreme of making all sides that need to bow into semi-circles.

Which when you dropped the FLAT tops on your rectangles also changed my assessment in post 2178 and which I explained in more detail in 2180.

Billy if you look at your cross section what you have done is created an eliptical cross section to your tank, but the much lower strength of that design has already been covered:

The required thickness of a hemispherical head is normally one-half the thickness of an elliptical or torispherical head for the same design conditions, material, and diameter

Arthur

 

[madanthonywayne]

A Chevy Volt caught fire three weeks after a side impact test due (they think) to a punctured battery.

http://www.freep.com/article/201111...eeks-after-crash-prompting-closer-look-safety

The NHTSA is considering new regulations requiring that electric cars have their batteries discharged after a collision.

In the meantime, I'd be sure to get my battery checked out after any collision if I had a Volt lest it burst into flames at some random time.

 

[Billy T]

Replying to post 2262:
One with a very good basic understanding of engineering and physics does not need to have had much experience with current technology when inventing quite a different technology. In fact, that often is a handicap to great progress as then the tendency is to try to marginally improve the current technology. For three well known examples:

(1) Kodak had more experience than any one in photographic film technology and marginally improved it for about 100 years, but did not invent digital cameras than are now making Kodak consider filing for bankruptcy.

(2) Swiss watch makers marginally improved the spring powered watch for more than 250 years, with many of the best costing > $1000, but they did not invent the more accurate $10 Timex.

(3) GE and others marginally improved the incandescent light bulb for about 100 years too, but others invented the big step forward. - Florescent light bulks that give the same illuminating with about 250% energy savings.

Likewise as discussed and described in post 2261, part of which is:
it acts like a gaseous filled NG tank at 180x 500 = 90,000 psi or almost three times more NG at 500 psi than the current 36,000 psi NG tanks do. AND of course a tank built for only 500 psi is much lighter and cheaper than the current technology NG tanks!


The future NG tank is NOT a marginal improvement on the current NG tank technology - The ANG corn cob filler and 500 psi tank too is a big step forward as it will give at least a 250% more gas stored per unit volume and about 50% reduction in tank weight with expensive wall materials replaced by corn cobs!.

Thus, I don't regret never having worked on design of conventional fiber tape wrapped tanks. If I had, I probably would be trying to marginally improve them. An exceptionally good engineering education* and 30 years of solving engineering problems is much better background from which to invent a big step forward - unfortunately I was not the first to do so. - Cannot get patents.

-------------------
* See foot note of post 2259 for details

 

[Billy T]

... (And unfortunately that diagram you posted indicates you have gone back to the refuted flat tops????)... Arthur

Of course not. - Figure is, as stated, to illustrate why all but one cell is "3-sided." I am limited when making "typed drawing" to the fonts available and [ or [[[[[[[[ was the best available for this.

 

[Billy T]

". . .that is another of your fabricated lies about me. . . . many examples of this dishonest policy of yours, many will be examples where you have done that to others in other threads, and ask James R if he agrees that for that and your many personnel attacks you don't need a cooling off holiday from posting activity. . . . your repeated dishonesty and personnel attacks . ."

You've made mistakes. So has he. Why can't both of you just move on?

SUMMARY: Asking not to have words put in my mouth is nothing I need to apologize for, but he sure should for doing so.
Try again to find an abusive post of mine as you say: "You both have made mistakes."

You did not give the post number where I did say:
". . .that is another of your fabricated lies about me. . . . many examples of this dishonest policy of yours, ..."

But he had stated that I said something which I had not. - I.e. put words in my mouth.

I have asked him to instead quote what I actually said by re-posting it. That nothing for me to apologize for, but he should apologize for putting words in my mouth I never said.

{post 2239}... You plainly said your tanks operated at the SAME pressure of the round tanks in use today Billy. That's 3,600 psi ... Arthur

{post 2241, in full} No, I said the text in black. You added the part in red. Putting words in my mouth AGAIN! Doing that is lying.
Even the black text does not quote me correctly. I have always and ONLY been saying the round tank and the flat tank operate at the same pressure, never that my tank operates at the 36,000 psi of CNG tanks in common use today.

For what must now be the 15th time, I have never specified any particular pressure for the flat tank to use. No need to - my equations are general - apply to any pressure. They ONLY calculate the ratio of storage volume to wall volume for both the flat tank and the conventional round tank.

 

[adoucette]

Likewise as discussed and described in post 2261, part of which is:
it acts like a gaseous filled NG tank at 180x 500 = 90,000 psi or almost three times more NG at 500 psi than the current 36,000 psi NG tanks do. AND of course a tank built for only 500 psi is much lighter and cheaper than the current technology NG tanks!


The future NG tank is NOT a marginal improvement on the current NG tank technology - The ANG corn cob filler and 500 psi tank too is a big step forward as it will give at least a 250% more gas stored per unit volume and about 50% reduction in tank weight with expensive wall materials replaced by corn cobs!.

Don't think so Billy.

They aren't saying to multiply 180 X the pressure as you are doing, they are saying:

The carbon briquettes can store 180 times their own volume of natural gas, or 118 g of methane per liter of carbon, at 500 pounds per square inch (psi)

http://www.greencarcongress.com/2007/02/new_highdensity.html

Which yields FAR less gas than you are thinking

Consider you want a 12 gallon ANG tank (because unlike the CNG, you don't get it all back, there is residual NG left in the ANG tank (it sticks to the carbon)), so this would be roughly equiv to the 8 gallon 3,600 psi CNG tanks in the Civic GX today:

1 Gallon of Gas Equiv of Natural Gas weighs ~5.6 lbs

5.6 lbs = 2,540 grams

http://www.tulsagastech.com/measure.html

So for a 12 gallon GGE tank

12 GGE = 2,540 x 12 = 30,480 grams of NG per tankful.

This adsorbtion material can store 118 grams of NG per liter of filler volume, at 500 psi.

30,480 grams divided by 118 grams/liter = 258 liters of volume for an ANG storage tank.

(At 3.8 liters per gallon, a 258 liters tank would be HUGE, about 68 gallons in size. But that is only for the volume of filler and doesn't actually include the tank structures itself, so the total size would likely be closer to 300 liters in size.)

In comparison, a 117 lb Steel 3,600 psi CNG tank that stores 12 GGE of CNG only has a total volume of 132 liters, less than half the size of the ANG tank.

http://www.dynetek.com/pdf/250_Bar_Specifications.pdf

Arthur

 

[adoucette]

But he had stated that I said something which I had not. - I.e. put words in my mouth.

I have asked him to instead quote what I actually said by re-posting it. That nothing for me to apologize for, but he should apologize for putting words in my mouth I never said.

LOL, you LIE about me LYING?

Get a grip Billy.

Here's what you claimed was in post 2239:

{post 2239}... You plainly said your tanks operated at the SAME pressure of the round tanks in use today Billy. That's 3,600 psi ... Arthur

But here is the actual post 2239:

You plainly said your tanks operated at the SAME pressure of the round tanks in use today Billy.

Of course I am considering pressure when I speak of a pressure tank. My assumption is that both the flat panel tank and the round take operate at the same pressure ”

That's 3,600 psi

As everyone can see, I included your actual post, which is what I based my claim on.

I did not "put words in your mouth".

http://sciforums.com/showpost.php?p=2853927&postcount=2239

Arthur

 

[Billy T]

{from post 2271}... But here is the actual post 2239:

You plainly said your tanks operated at the SAME pressure of the round tanks in use today Billy.

Of course I am considering pressure when I speak of a pressure tank. My assumption is that both the flat panel tank and the round take operate at the same pressure.

As everyone can see, I included your actual post, which is what I based my claim on. I did not "put words in your mouth"... Arthur

No my “Of course I am considering pressure….” is from old post 2148, not post 2239, and more importantly DOES NOT MAKE ANY comparison to “Same pressure as the round tanks of today” I never said that in ANY post. Those words are your fabrication stuffed into my mouth. Here is the ACTUAL POST containing “Of course I am considering pressure…”

[POST 2148, the full paragraph in question}...
Of course I am considering pressure when I speak of a pressure tank. My assumption is that both the flat panel tank and the round take operate at the same pressure - perhaps 20% below the pressure that would rupture them. At the same pressure, tank volume to mass ratio is the important factor. ...

Which is replying to adoucette’s question/ false statement/ about my “analysis.”

{post 2146 first part}Your analysis was NOT about PRESSURE Billy. You made the assertion but haven't shown any math around shapes that can contain stress from pressure, and that's the issue, not just volume. ... Arthur

SUMMARY: Clearly we were both speaking of my analysis, with no mention of your fabricated:
“Same pressure as the round tanks of today” \

So you are even lying about your lies.

 

[Billy T]

To adoucette: A brief comment on your post 2270:

You compare the ANG (corn cob filled) 500 psi flat tank to a gasoline tank in that post. I agree gasoline has about the best possible energy density of anything. Certainly much better than battery powered EVs, which is what this thread is about.

I am only suggesting, as I have for several years here and in other threads, that there are better alternative to gasoline than batteries. To again name two I think will share the market in the future when gasoline is not affordable:

(1) Cheap and abundant (for 100 years or so) NG stored in "second generation" flat compound (many parallel cells) ANG tanks.
and
(2) Alcohol made for sugar cane, certainly not from corn, and only small fraction made from sugar beets (mainly in Russia and Southern France).

Thus your stating my flat NG tanks, which are just now commercially available and used now almost entirely for propane, as ANG filler is not yet commercially available, is irrelevant to the discussion. Merits no line-by-line reply.

 

[adoucette]

No my “Of course I am considering pressure….” is from old post 2148, not post 2239, and more importantly DOES NOT MAKE ANY comparison to “Same pressure as the round tanks of today” I never said that in ANY post. Those words are your fabrication stuffed into my mouth. Here is the ACTUAL POST containing “Of course I am considering pressure…”

Of course you did Billy.

Amazingly the flat panel NG storage tank holds 60% more NG than the round one when both use the same amount of material, weight the same, and have the same bursting pressure limit.

Following the thread, the only "round one" that had been discussed was the standard 3,600 psi tank in use today, same as is in the Civic GX that started this whole discussion.

I'm done with your LYING about this Billy.

It really is pathetic.

Arthur

 

[adoucette]

To adoucette: A brief comment on your post 2270:

You compare the ANG (corn cob filled) 500 psi flat tank to a gasoline tank in that post.

No I didn't Billy.

I actually compared it to a standard round CNG 3,600 psi tank.

I only used Gallons of Gasoline Equivalent, so we could make a comparison to a gasoline tank for estimating range and I also converted the total liters of the ANG tank to gallons so one could compare it's physical size to an actual gasoline tank in a typical car.

So unlike your claim, that you could store three times more NG at 500 psi than the current 36,000 psi NG tanks, the reality is just the opposite.

For a 12 Gallon Gas Equivalent ANG tank, where the filler adsorbs 118 grams of NG per liter of filler volume at 500 psi, as per the link posted:

http://www.greencarcongress.com/2007/02/new_highdensity.html

12 GGE = 2,540 x 12 = 30,480 grams of NG per tank.

30,480 grams / 118 grams/per liter of filler = 258 liters of volume for a 500 psi ANG storage tank.

In comparison:

A 117 lb Steel 3,600 psi CNG tank that stores 12 GGE of CNG only has a total volume of 132 liters.

That's less than half the physical size of the 500 psi ANG tank, and more importantly, virtually all the NG in a CNG tank can be used, retention in an ANG tank can be 15% or more of the adsorbed NG.

Arthur

 

[Billy T]

No I didn't Billy. I actually compared it to a standard round CNG 3,600 psi tank.
I only used Gallons of Gasoline Equivalent, so we could make a comparison to a gasoline tank for estimating range and I also converted the total liters of the ANG tank to gallons so one could compare its physical size to an actual gasoline tank in a typical car. ... Arthur

OK, I guess I skimmed your post too quickly and falsely thought you were comparing to gasoline. Glad you were not.

There are unknown factors to consider:
(1) ANG from corn cobs is one of many possibilities - chosen in part as they are a disposal problem where UM is located. For example, how much better would "activated charcoal" from other sources be? - It is very early in the ANG technology research area - nothing yet for sale.

(2) What if the 500 psi increased to 1,800 psi (half the 3,600 of current tanks)? I guessed in post replying to Billvon that would make very little increase in the stored NG as it was stored mainly as an incompressible liquid surface film.

He said that was very wrong - something about and exponential relationship to pressure. Of course I was very interested and asked for link(s) to his source(s), but he has yet to reply.

(3) The researchers at MU are also investigating AHG (H for hydrogen) and have found that a little boron (as I recall) greatly increases the stored hydrogen.

In later a post I explained why I guessed there would be little increase with pressure, but it is more complex than the factors I included, which I think do show the rate of molecule leaving and striking the liquid surface are both roughly linearly increasing with pressure; however, I now acknowledge that even a very slightly different dependency upon pressure could make the THICKNESS of the liquid film change and that is what is important.

I hope what controls the thickness of surface adsorbed films is reasonably well understood, but suspect much is not; for example why does a little boron increases the H2 storage, etc.

Ironically, some of the "micro-pore technology" being explored for very rapid recharge electrodes of batteries may be good as ANG tank filler materials and thus make batteries the researchers think they are making more competitive, become part of technology's abandoned history instead.

 

[Billy T]

Following the thread, the only "round one" that had been discussed was the standard 3,600 psi tank in use today, same as is in the Civic GX that started this whole discussion. ... Arthur

You and billvon have frequently made reference to 3,600 psi standard round CNG tanks. In contrast I have never specified any pressure and now at least 15 times pointed that out - noting that my equations apply to any pressure.

Thus, when I refer to a round tank operating at the same pressure as a compound flat tank there is no reference to 3,600 psi stated or even implied*, especially as I have so many times stated I am only comparing the tank capacity to the volume of the tank walls. That is all my equations do and they do that for ANY pressure. These volume ratios are a function of tank geometry ONLY and do not depend upon tank pressure. No need for me to ever assume one.

If you (or others) ignore my very explicit and frequently made statement and on your own assume I must be meaning /comparing to / a 3,600 psi tank, I cannot stop you. - God knows, with 15 or so statements that I am not, I have tried to.

Again, for the 16th time: I never have specified any pressure for the tanks - only that it is the same for both in my equations (as is the safety factor).

Billvon did specify 3,600 psi when he asserted 3,600 psi would rip the specific tank I had just described apart, make it too heavy for the car to carry, etc. - So yes, when proving that was not true, I did plug that pressure into my analysis. That is not my assuming the tanks would operate at 3,600 psi; that is only showing Billvon was not correct with his guesses.
--------
* I certainly am not saying "... tanks operated at the SAME pressure of the round tanks in use today Billy. That is 3,600 psi. " Those are words you fabricated and stuffed in my mouth!

 

[billvon]

both[/b] have made mistakes."

I just listed an abusive post you made. Calling someone a liar, dishonest etc is abusive. You yourself seem offended when Adoucette calls you a liar; I would suggest you use the old "treat others as you would be treated" maxim.

And yes, you've made mistakes. Your most recent one is referring "the 36,000 psi of CNG tanks in common use today." You meant 3600 PSI tanks I am sure. Does that mean you are a deceitful liar, trying to mislead people to cover up your ignorance? Or did you just make a simple mistake? I'm going to assume the latter. It's not a big deal; move on.

I have asked him to instead quote what I actually said by re-posting it. That nothing for me to apologize for, but he should apologize for putting words in my mouth I never said.

That is an approach better suited for grade school than for adults posting on a board that is (at least in theory) about science.

 

[Billy T]

I just listed an abusive post you made. Calling someone a liar, dishonest etc is abusive. ...

Not if it is true and you can prove that. If they falsely say that you said "X" and you did not, then you have an obligation to post a correction telling that what they claimed you said (instead of actually re-posting what you said) is false.

Saying it is a lie is OK, especially if they keep repeating it as then it isn't just a typing error as my 36,000 instead of 3,600 was. (I suffer from mild dyslexia, so don't notice some errors of typing I make.)

... You yourself seem offended when Adoucette calls you a liar; I would suggest you use the old "treat others as you would be treated" maxim. ...

No, not offended by his lying, only annoyed and needing to reply to correct when he claims I said something I did not. I was offended by him saying I lacked qualifications in engineering and physics to be commenting on gas storage tanks.

Adoucette did lie when he said (in post 2239) that I had posted /said the part now red below:

Quit LYING. You plainly said your tanks operated at the SAME pressure of the round tanks in use today Billy. ... That's 3,600 psi … Arthur

In post 2271, Adoucette repeated the lie and again cited post my post 2239 as containing those “red words” about me saying my tank operated at the same pressure as the round tanks used today. Read my reply in post to that in 2272.

Those words about my comparing to tanks now “in use today” are not in my post 2339 nor any other post I have made. I have many times used the words “at the same pressure” but ALWAYS referring to the pressures in the flat tank and the round tank of my math models being the same (just as I assume their safety factors are the same without that being a reference to the safety factors of tanks in use today). NEVER by “pressures being the same” or “safety factors being the same” am I referring to the pressures and safety factors found in a real world CNG tanks at 3,600psi or any other specific pressure.

I have now about 16 times stated: “that I have never specified ANY pressure” as my efficiency comparison between the flat tank and the round tank is totally independent of their max pressure. The efficiency ratio (between flat and round tanks) ONLY depends upon the flat tank geometry.

This is because ALL round tanks, when at the max safely contained pressure, have the same efficiency. I.e. if you double the diameter, then the wall thickness to hold the doubled stress must double too. The circumference also doubles. The total wall material volume increases by a factor of four – exactly the same factor of four as the storage volume increases. Hence ratio of storage volume to wall volume, the tank’s “efficiency,” remains unchanged –does not vary with tank diameter.

In contrast, the flat tank efficiency must be calculated for each tank as it is a function of the tank thickness, width & length. That is what my equations do so I can then compare to the constant efficiency of all round tanks.

I have never referred to the tanks “used today” as Adoucette claimed I did and certainly not to one at 3.600 psi (or any other particular pressure). In response to Billvon’s statements about a specific geometry flat tank, failing etc. at 3,600 psi, I did do a calculation using that pressure to prove his assertions were not true. But again, for the 17th time, I have never specified the operational pressure of any tank. (Others have specified 3,600 & 500 psi and on occasion I have quoted them.)

I have already requested Adoucette to tell which post of mine is referring to tanks “used today” he has not been able to, nor will you, as I never did make that reference. Ergo: Adoucette REPEATEDLY saying I did, is lying.

 

[adoucette]

Adoucette did lie when he said (in post 2239) that I had posted /said the part now red below:

In post 2271, Adoucette repeated the lie and again cited post my post 2239 as containing those “red words” about me saying my tank operated at the same pressure as the round tanks used today. Read my reply in post to that in 2272.

Those words about my comparing to tanks now “in use today” are not in my post 2339 nor any other post I have made. I have many times used the words “at the same pressure” but ALWAYS referring to the pressures in the flat tank and the round tank of my math models being the same (just as I assume their safety factors are the same without that being a reference to the safety factors of tanks in use today). NEVER by “pressures being the same” or “safety factors being the same” am I referring to the pressures and safety factors found in a real world CNG tanks at 3,600psi or any other specific pressure.

BS, I didn't put quotes around that, I stated what your post meant and then quoted your post to show that indeed you were comparing your new means of storage to 3,600 psi CNG storage today. Deny it all you want but I think it is clear to all who read your posts.

I have now about 16 times stated: “that I have never specified ANY pressure” as my efficiency comparison between the flat tank and the round tank is totally independent of their max pressure. The efficiency ratio (between flat and round tanks) ONLY depends upon the flat tank geometry.

This is because ALL round tanks, when at the max safely contained pressure, have the same efficiency. I.e. if you double the diameter, then the wall thickness to hold the doubled stress must double too. The circumference also doubles. The total wall material volume increases by a factor of four – exactly the same factor of four as the storage volume increases. Hence ratio of storage volume to wall volume, the tank’s “efficiency,” remains unchanged –does not vary with tank diameter.

Apparently the CNG tank makers didn't get your memo Billy.

http://www.cng.us.com/pdfs/CNGci_Type1.pdf

Compare these two tanks of roughly the same length (within 3%) but with different diameters:

Volume	GGE	Dia.	Length	Weight
75	6.7	10.75	61.81	187.6

To this tank:

Volume    GGE     Dia.    Length    Weight
170	15.2	15.98	59.96	377.4

127%	127%	49%	-3%	101%

The volume efficiency goes up roughly 30% faster than the weight.
Which is why we don't see many real small CNG tanks.

I have never referred to the tanks “used today” as Adoucette claimed I did and certainly not to one at 3.600 psi (or any other particular pressure). In response to Billvon’s statements about a specific geometry flat tank, failing etc. at 3,600 psi, I did do a calculation using that pressure to prove his assertions were not true. But again, for the 17th time, I have never specified the operational pressure of any tank. (Others have specified 3,600 & 500 psi and on occasion I have quoted them.)

But when you did that calculation you DID in fact claim your tanks could support 3,600 psi Billly.

Which is why you can't point to a Propane tank at less than 200 psi and say it proves you were right about building your flat tank to handle CNG pressures.

I have already requested Adoucette to tell which post of mine is referring to tanks “used today” he has not been able to, nor will you, as I never did make that reference. Ergo: Adoucette REPEATEDLY saying I did, is lying.

All references you made to a ROUND tank were not qualified in any way and so in the absence of any qualification the references are clearly taken to be round CNG tanks in use today, as in the Civic GX that started this topic, which are 3,600 psi.

Arthur

 

[adoucette]

OK, I guess I skimmed your post too quickly and falsely thought you were comparing to gasoline. Glad you were not.

There are unknown factors to consider:
(1) ANG from corn cobs is one of many possibilities - chosen in part as they are a disposal problem where UM is located. For example, how much better would "activated charcoal" from other sources be? - It is very early in the ANG technology research area - nothing yet for sale.

So what that they created it from corn cobs?

researchers at the University of Missouri-Columbia (MU) and Midwest Research Institute (MRI) in Kansas City have created carbon briquettes with complex nanopores capable of storing natural gas at an unprecedented density of 180 times their own volume

Meaning that's the BEST that has been done so far with ANG.

(2) What if the 500 psi increased to 1,800 psi (half the 3,600 of current tanks)? I guessed in post replying to Billvon that would make very little increase in the stored NG as it was stored mainly as an incompressible liquid surface film.

Won't help much. They didn't pull 500 psi out of their butt. The adsorbtion gain levels off at 500 psi and after that pressure CNG starts delivering more gas per volume (see figure 1).

http://www.anl.gov/PCS/acsfuel/preprint archive/Files/43_3_BOSTON_08-98_0575.pdf

The two combined points make your statement:

Thus, one can easily make the flat panel NG tank hold more than twice as much NG as a around tank of the same weight. !!!

NOT TRUE, even if as you are now claiming, you were talking about using the tanks for ANG storage technology because as we've seen in comparison to ANG storage, a 117 lb Steel 3,600 psi CNG tank that stores 12 GGE of CNG has a total volume of 132 liters, less than half the size of the ANG tank of the same capacity.

We also know that they can build Composite CNG tanks that weigh in at up to 70% less than steel tanks, or roughly a 40 lb composite tank for 12 GGE of CNG, which means that the weight of the CNG tank isn't that big of an issue, and if you have to build a 500 psi ANG flat tank that holds twice the volume, then add in the weight of the filler, there isn't going to be any great weight savings anyway.

http://lincolncomposites.com/products/cng-fuel-tank-advantages/

Finally, in this post, you computed your CAPACITY of your tank:

Thus, the average volume of one tube would be: 1x4x160 = 640cc or 0.64 liters. If the width of the car is 1.4 meters, then there could be about 125 parallel tubes. So the flat tank's total volume could be: 125x0.64= 80 liters, which is 21.134 gallons, bigger than most gasoline tanks, yet making the floor less than two inches thick.

But when I called you on it, that CNG didn't have nearly the same energy per gallon as Gasoline did:

And if only CNG had the energy density of gasoline.
It takes 728 cubic inches of CNG to equal 1 gallon of Gasoline.
Your supposed revolutionary engineered flat tank doesn't have the equiv of 21 gallons of gasoline Billy, only 6.7 gallons.

Because the Gasoline Equivalent Volume is less than 7 Gallons which is much less than the quite small 12 gallon tank in the Prius.

You fired back, and used the GGE for CNG as your metric, thus implicitly stating that you were operating your flat tank at the same pressure as CNG (You couldn't have been writing about ANG since as we have seen ANG has about half the capacity per volume).

but 7 gallons of gas at 35 or 40 mpg fuel efficiency will take you up to 280 miles between fill ups. I.e. at least twice what most even pure electric cars can do, and at less than $1/gallon equvillent cost per mile.

OOPS

Arthur

 

[billvon]

I have never referred to the tanks “used today” as Adoucette claimed I did and certainly not to one at 3.600 psi (or any other particular pressure).

Yes, you did - you quite clearly compared your tank to standard tanks operating at 3600 PSI. But again, I don't think that makes you an evil, deceitful person. It just means you made a mistake, as you did with the 3600 vs 36000 PSI thing. We all make mistakes.

Why all the defensiveness? There is indeed some utility to prismatic tanks operated at lower pressures, both because you don't always need the range 3600 PSI gives you and because there are tricks you can do (like adsorbers) that make even low pressure tanks hold a reasonable amount. Why not talk about that, instead of claiming you didn't say something you did?