Electric cars are a pipe dream

Discussion in 'General Science & Technology' started by Syzygys, May 20, 2010.

  1. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Tell that to Nisan, who is selling the pure electric Leaf better than the gas/electric hybrid, the GM Volt. I agree the CNG would inititially be only a second car used in cities with CNG filling stations or by a few others who had NG heating & high pressure pump, and wanted the less than $1/gallon gasoline equivalent economy. Like the lab tech of my APL group who converted his gas car to a dual fuel (CNG & gasoline) 35+ years ago. He lived up on the Susquehanna River and drove to APL in Howard County MD 5 round trips each week.

    Back then, cars had carburators instead of fuel injection. I seriously considered putting a propane tank (like one my Bar-B-Que used) into the car to avoid part of the road tax on gasoline. Idea was just to "bleed" a little propane into the air intake and let it get sucked in with the air, but I never did it.
     
    Last edited by a moderator: Nov 1, 2011
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  3. adoucette Caca Occurs Valued Senior Member

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    The difference in sales volume between the two is not enough to jump to any conclusions Billy, particularly since the Volt up until recently was quite a bit more expensive than the LEAF. Still it is somewhat telling that both EV vehicles are selling more than the one CNG vehicle that is available.

    BUT

    The LEAF is being sold primarily in just a few states where indeed, via a HUGE grant from the Federal Government THOUSANDS of electrical charging stations are being installed and then because the availability of electricity is so ubiquitous, one presumes that most LEAF buyers are those who can charge their cars while they are at work, something which would be quite rare (and damn expensive) for a CNG car buyer.
     
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  5. billvon Valued Senior Member

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    Spherical tanks (specifically Moss tanks) operate up to 15psi. Compare that to a prismatic tank which can go to 2 or 3psi tops.

    Primarily plywood boxes holding expanded styrene or glass fiber insulation.

    Agreed - but that's pretty unique to a vacuum, since a vacuum does not conduct heat, and the foil cuts down on radiative transfer.

    If LNG stayed liquid then it would be very, very easy to transport. No insulation needed. But it doesn't - it wants to boil off if it is not kept very cold. The higher the pressure on a liquid, the higher the temperature it boils at - and the more cargo you have left at the other end of the trip.
     
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I tried to find a link stating that as you did not give one. Few even mention pressure but this one states ALL ocean transport tanks are NOT pressurized. Can you find link telling they are wrong - that some are pressurized? I don't think that would be worth much - see footnote.

    "... All LNG ships are double hulled and rely on insulation to keep LNG liquid at -260°F (-162.2°C). The cargo is carried at atmospheric pressure in specially insulated tanks, referred to as the cargo containment system, inside the inner hull. ..."

    From: http://www.marinelog.com/DOCS/PRINTMMV/MMVFebLNG2.html

    I did not see any date but the article is very recent as they discuss the just proved ABS tanks (none built yet, I think) and also say:

    "... When is a sphere not a sphere? When it's a vertically stretched sphere. Kawasaki Kisen Kaisha, Ltd. ("K" Line), in partnership with Osaka Gas International Transport Inc. ) and Nippon Yusen Kaisha (NYK), has concluded a contract for a new 153,000 m3 LNG carrier with Kawasaki Shipbuilding Corporation.

    The ship will be mainly used to carry LNG for Osaka Gas from the Qalhat LNG Project in Oman from 2009. It will have four spherical LNG tanks three of which are being given a 2 m vertical stretch. This advantage enables tank capacity to be increased by about 5.5 percent but within almost the same ship dimensions and with the same fuel oil consumption. ..."

    I.e. a sphere is not best - they are slightly moving to the stretched tubes my flat tanks use.
    ------------
    * If boiling point could be raised 5 degrees C by 15 psi added then LNG would boil at -157.2C. If the air temperature is 25.8C then the thermal transport into tanks is only (25.8 +157.2) / (25.8+162.2) =183 / 188 = 0.973 or LESS than a 3% reduction in the already (due to good insulation) small loses. 25.8C = 78.44F. If the air were hotter the fractional reduction in losses with pressurized tank would be even less but of course the hotter the air is, the more you lose. - A second reason (first is they are much shorter) why Arctic routes to Asia will be used for LNG transport in a decade of so when a little more Arctic ice has melted.

    PS, I am just guessing, but the extra weight of the pressurized tank, would either limit the volume carried or sink the ship deeper in the water - In either case the ship would burn more fuel per gallon of of LNG transported - so the slight reduction of loses with a pressurized tank might even have a negative cost benefit! If that is true, then you will search long and hard trying to find an article showing that not ALL ocean transport tanks operate at atmospheric pressure.
     
    Last edited by a moderator: Nov 1, 2011
  8. adoucette Caca Occurs Valued Senior Member

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    Not at all, they are describing a typical CYLINDER, nothing at all like your Unobtanium Flat tank.

    Arthur
     
  9. adoucette Caca Occurs Valued Senior Member

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    7,829
    Not long or hard...

    Minimum boil off/max oil :- In this mode tank pressures are kept high to reduce boil off to a minimum and the majority of energy comes from the fuel oil. This maximises the amount of LNG delivered but does allow tank temps to rise due to lack of evaporation.

    http://en.wikipedia.org/wiki/LNG_carrier
     
  10. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    Yes that is one of three possible modes, but does not contradict the article I cited. Let’s not "cherry pick" but give the full text, which is:

    "... There are three basic modes available:

    Minimum boil off/max oil: - In this mode tank pressures are kept high to reduce boil off to a minimum and the majority of energy comes from the fuel oil. This maximizes the amount of LNG delivered but does allow tank temps to rise due to lack of evaporation. The high cargo temps can cause storage problems and offloading problems.

    Max boil off/Minimum oil: - In this mode the tank pressures are kept low and you have a greater boil-off but still there is a large amount of fuel oil used. This deceases the amount of LNG delivered but the cargo will be delivered cold which many ports prefer.

    100% Gas: - Tank pressures are kept at a similar level to max boil off but this is not enough to supply all the boilers needs so you must start to "force". To force a spray pump is started in one tank to supply liquid LNG to the forcing vaporizer this tanks liquid LNG and turns it into a gas that is useable in the boilers. In this mode no fuel oil is used.

    Recent advances in technology have allowed reliquefication plants to be fitted to vessels, allowing the boil off to be reliquefied and returned to the tanks. ..."

    Obviously, if the boil off is re-liquified and pumped back into the main tanks less energy is required if they are NOT pressurized. Furthermore, 100% of the NG taken on board at the source is delivered to the discharge post - avoiding the 2 to 6% losses. (Losses vary with the length of the trip and air temperature along the route.)

    Your reference then goes on to say there is an additional cost saving by operating in this more "re-inject the boil off NG" modern mode. Namely no longer must the ship's engine be "dual fuel" but can be more efficient using diesel engine optimized for diesel oil only. In the old days, the boil off was feed into the dual fuel engines, rather than simply being 100% wasted by venting to the air.

    In my original post, I noted that despite not seeing any publication date, it was very up to date - knew that ABS has just recently been approved for LNG tanks and other fact less than year old.

    Thus I continue to think what this very modern article states ("ALL LNG ships operate without pressurization") is true. The wiki link you give does not state that any ship uses pressurization - only that there are three conceptual modes of operation; and when not misleadingly "Cherry Picked" tells that the most efficient, cost wise mode is modern UN-PRESSURED re-injected NG mode as then there is zero loss of NG and the ship's motors are more efficient as they are optimized for a single fuel (not a dual fuel compromise).

    Again I think you will be hard pressed to find a modern article that tells the LNG ship is operated with its tanks artificially pressurized to raise the boiling temperature. Perhaps, years ago, some did, and all will have slight natural pressure increase as some slight pressure is associated with the venting flow.

    Try again to find a modern article which contradicts the modern article I cited, but please no more "cherry picking".

    BTW, I don't search much so I am not good at it. I use my extensive knowledge of classical physics and calculate instead. (If you search the internet enough you can find lots of false "facts.") By this method in recent post I concluded that pressurizing could reduce the evaporation losses by less than 3% but the losses are usually no more than 5%, so pressurization could save approximately 0.05x0.03 = 0.0015 of the LNG. That is why without searching, I doubted billvon's claim that LNG ships were artificially pressurized to rise the boiling temperature. And also why I doubted that your cherry picked wiki actually said what you claimed it did.
     
    Last edited by a moderator: Nov 2, 2011
  11. adoucette Caca Occurs Valued Senior Member

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    No Billy, the article says exactly what Billvon's claim was: that Moss tanks are pressurized and pressure is used to reduce boil off
     
  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    “one standardatmosphere is exactly equal to 101.325 kPa” From: http://en.wikipedia.org/wiki/Pascal_(unit)

    From your link: “{Moss} Tanks normally have a working pressure of up to 22Kpa in normal use.”

    They are not pressurized artificially (by pumps) but the evaporation flow is restricted so that it is allowed to bring the tank pressure up to less than ¼ of an atmosphere, but that is the normal upper limit. Perhaps typically they operate with a couple of psi internal pressure.

    I have already stated that some slight internal pressure is required to move the boil off gases thru the plumbing to the re-refrigeration system which will re-liquefy them for re-inject back into the main tank. The boiling temperature elevation of few psi is extremely small and makes an insignificant reduction in the evportion rate and with re refrigeration & re-injection, ABSOLTUTELY NO REDUCTION in the losses, which was why Billvon thought pressurization was done:
    BTW his "up to 15psi" seems to be wrong if your Wiki article is correct. Wiki states: "up to 22 kPa" which is (22/101.325)x 14.7 psi = 3.2 psi.

    I have no direct knowledge about LNG transport practices but assume Wiki is more correct than Billvon.

    In any case my cited, very modern, article's statement seems to be correct - No modern LNG ship uses pumps to pressurize the LNG tank to elevate the boil temperature and thus reduce evaporation losses. Since the loss reduction would be very small (< 0.002) I strongly doubt it was ever done, but it is conceptually possible. In some older "dual fuel" ships the slight natural pressure elevation moved the evaporated gaseous NG thru the piping to the dual fuel ship motors.

    I won't defend the accuracy of the cited article more - if you think it is false, attack the author, not me. I am only quoting him. I have shown by physic and calculations that there is essentially nothing to gain in the way of reduced losses by artificially pressurizing the tanks so continue to think the article is correct, instead of adoucette & Billvon.
     
    Last edited by a moderator: Nov 2, 2011
  13. adoucette Caca Occurs Valued Senior Member

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    I've seen things saying the pressures do go as high as 15 psi (even higher) but it would appear that that isn't the norm.

    Apparently most LNG carriers are going the low pressure reliquification route because it's cheaper to carry more fuel then you can in spherical tanks.

    Of course this diversion has no bearing on our discussion about the Epic Failure in your design of your integrated Unobtanium flat tanks.
     
  14. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    As edited, I agree with last sentence, except that my math / physic modeling on LNG was basically correct and lead me to question Billvon's statement about LNG ocean tanks being pressurized to raise boiling temperature for the purpose of reducing losses. Perhaps my math, which you never refuted directly, and physic modeling of the flat tank alternative is correct too?

    Anyway I am writing a more complete and more careful math model (will include the fillet volumes; is described in a Cartesian coordinate frame, etc.) which I hope to post as a new thread in the physics forum to end this LNG tanker detour of the EV car thread. I will just close by again stating the first applications, if any, will be as the roofs of 18 wheeler trucks (or possibly city buses).
     
  15. adoucette Caca Occurs Valued Senior Member

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    Nope.
    Not a chance Billy.

    And YES, I did refute your BS about your Unobtanium tank.

    No one believes you, but you Billy.
     
  16. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Not my math proof - just by noting irrelevant things like isolated tanks are round or, with picture no less, that large airplanes are round.
    That may well be true, now, but if I am correct, not for ever. The truth of physics and math is not decided by votes. I may have made a mistake in the math or physics I posted, but showing a picture of an airplane cross section does not prove I did.
     
    Last edited by a moderator: Nov 2, 2011
  17. adoucette Caca Occurs Valued Senior Member

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    Why yes it did Billy.
    Airplanes are one of the most sophisticated and highly engineered things man has ever constructed. The Fuselage is a pressure vessel and it is round for a reason.

    But of course that wasn't all.

    I showed the math that showed your Unobtainium tank would use far more linear walls and thus be FAR heavier and contain far less CNG than an equivalent Cylinder.

    I showed the journal article that explained that rectangular pressure tanks needed far thicker walls for the same pressure.

    I pointed out that the tanks require periodic inspection and after any impact and yet you haven't suggested any way that could be done with your corrugated tube tank, nor addressed the cost impact if the tank is integrated into the structure and needs to be replaced.

    At the same time you have not shown that it could even be built and your use of the simple structure like a spar (just a long rod) as an example of how your very complex structure could be built is just laughable. Indeed you have shown no examples of extruded pressure tanks to support your contention that that is a viable construction technique.

    Finally there is the fact that though Millions of CNG pressure vessels are made each year, and that they are also made from wrapped layers of composites and carbon fiber and yet you haven't been able to show one that isn't in the shape of a cylinder, or one that is extruded.

    Indeed you've done nothing to support your ridiculous assertions but your own bluster.

    Arthur
     
  18. adoucette Caca Occurs Valued Senior Member

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    7,829
    Well the October Sales figures are in:

    Volt sales are up significantly and even exceeded the LEAF sales, indicating that the price cut for the Volt and the price increase for the LEAF had a definite impact on buyers.

    GM sold 1,108 units in October (Still below LEAFs August sales even though an increase of almost 50% over September’s 723 units), and that puts the Volt at 5,003 vehicles for the year

    Nissan sold 849 LEAFs, which is down for the second month in a row and now is quite a bit below August's peak sales. Net for the year is 8,048.

    Or a combined average of 1,305 units of both EVs per month for the year.

    Still peanuts.

    On the other hand, even though it was another miserable month for EV sales, the Feds still shoveled out another $14.6 Million dollars to subsidize these lackluster sales.

    Arthur
     
  19. billvon Valued Senior Member

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    Yep. Hopefully EV sales will follow the same path that hybrid sales did, and quickly take off on their own.
     
  20. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Adoucette has a policy of never admitting he is wrong or apologizing for personnel attacks such as in following posts:
    Before spending for a patent, I searched and found:

    Please Register or Log in to view the hidden image!

    And read there: “…This reduced weight increases a vehicle’s fuel efficiency, reduces suspension load and maintains a vehicle’s factory handling characteristics. The tanks are also claimed to offer superior safety in the event of rear-end collisions, having successfully undergone crash trials in police cars in the United States, ...{at up to 100mph}. “Our tanks exceed every crash safety standard in the world.”

    PPI is now designing a wedge-shaped version of the Conformable Tank that provides additional ground clearance for off-road vehicles. …”

    You can buy my “Unobtanium” flat tank with "tension webs" from PPI: http://gastoday.com.au/news/rocket_scientists_invent_flat_lpg_tank/004429/ which states: "our tanks are actually designed by rocket scientists at Thiokol Corporation." Here is more on it from PPI:

    “…Modular construction - the tank is comprised of extruded, modular ‘cells’ that can be customized to the ideal length and width, maximizing capacity in the space available. Global patented design …" - I searched before spending for an “unobtanium" tank patent. (It's the patent which is now “unobtanium" - you can buy the tank already!)
    Quoted text from: http://www.ppidts.com/propanep/construction.html

    I won’t hold my breath waiting for Adoucette to admit his errors or apologize for personnel attacks as he never does.

    * I am an unusually well qualified engineer, with 30 years working experience at the Applied Physics Lab. More details in post partly reproduced below. Just a few years too late inventing the flat tank with tension webs to get the patents.

    Needless to say, but there was never any answer to those two final questions.
     
    Last edited by a moderator: Nov 10, 2011
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Very doubtful. By inserting cheap, high-surface-to-volume materials, like N2 baked corn cob carbon briquettes, into a flat NG tank you get 180 times the corn cob volume in NG, adsorbed on the surface AS A LIQUID at only 500 psi which is the standard pressure of long natural gas pipe lines - no need for any at car pumps if near one (or it's soon to exist smaller ID extensions making car fuel distribution much cheaper than delivery by gasoline tank trucks and their well-paid drivers.)!

    The surface area inside a carbon briquette, “hockey puck,” which is approximately 3.5 inches in diameter and 1.5 inches tall, is equal to about 60 football fields. ..." More at: http://munews.missouri.edu/news-releases/2009/0513-suppes-pfeifer-natural-gas-license.php

    I have many prior post stating NG (and / or sugar cane alcohol) is the future. EVs are an expensive bad dream funded by foolish governments at tax payer's expense.
     
    Last edited by a moderator: Nov 10, 2011
  22. billvon Valued Senior Member

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    21,635
    I agree that there are many ways to store fossil fuels. But while storing them well gives you pretty good range, it does not solve the problem of lack of those fuels.

    Hmm. We have 30 or so of those "bad dreams" in our parking lot right now. People here really like them.
     
  23. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    They should – taxpayers paid $11,188 for each EV car sold last month (post 2217 data) Sustainable cost? - No, NG is so much cheaper.

    billvon: "the problem {is} lack of those fuels." There is huge amount of NG in US - Perhaps more energy than in all world's economically recovearble oil! Should last more than 100 years if car fuel were the only use and be very much cheaper per mile driven.
     
    Last edited by a moderator: Nov 10, 2011

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