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Thread: Electric Car Challenges

  1. #76
    Quote Originally Posted by John Stankus View Post
    The Joule-Thomson inversion temperature is fairly low for hydrogen so the gas would warm as it expands... might be a safety issue with a flammable gas leaking.

    There are definitely safety issues with transporting liquid ammonia
    This is interesting. Liquid hydrogen has to be kept under pressure to keep it in its liquid state. In transporting liquid hydrogen, some heat is bound to penetrate the tank and warm some of the liquid hydrogen, causing it to transition to a gas. Seems that would cause the pressure to increase but I assume they have a pressure vent that allows some hydrogen gas to escape while maintaining the critical pressure.

    But if the hydrogen warms as it expands, it seems that you could have a runaway condition - some liquid hydrogen would convert to a gas, but that would add heat to the contents of the tank, and that would cause more hydrogen to transition from liquid to gas,

    What's your take on this?

    Mike
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  2. #77
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    I could be wrong but there was an agricultural fertilizer company in northern Illinois that used propane powered trucks for their representatives back in the late '60s when I lived there before qualifying for the draft.
    Ken

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  3. #78
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    Another issue with hydrogen is hydrogen embrittlement. Steel exposed to hydrogen can become brittle which can lead to catastrophic failure. There are ways to prevent it, but it is an issue.
    A comment to those who say EV's aren't for everyone. So what? ICE vehicles aren't for everyone, heck cars (or trucks) aren't for everyone. Lot's of people in big cities don't own cars. Some people still ride horses. We don't need to get to 100% EV's to reduce CO2 emissions and fight climate change.

  4. #79
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    Quote Originally Posted by John Stankus View Post
    The Joule-Thomson inversion temperature is fairly low for hydrogen so the gas would warm as it expands... might be a safety issue with a flammable gas leaking.

    There are definitely safety issues with transporting liquid ammonia

    We transport huge amounts of liquid ammonia here in farm country in the spring and fall specifically. I'm unaware of any safety issues that have arisen. Leaks are quite rare. Them meth cookers used to steal it for their processes. Not so much these days so maybe they found a replacement.

  5. #80
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    Quote Originally Posted by Ken Fitzgerald View Post
    I could be wrong but there was an agricultural fertilizer company in northern Illinois that used propane powered trucks for their representatives back in the late '60s when I lived there before qualifying for the draft.
    Ken that used to be quite common in this area but I don't know if anyone still does the propane conversions. There are semis running LNG and some citites are also powering their buses this way.

  6. #81
    Quote Originally Posted by Bill Dufour View Post
    Hydrogen is the smallest molecule and hence leaks the easiest of any gas or liquid. To test vacuum chambers they will pressurize with hydrogen and sniff for any leaks. It will leak out gaps that air cannot fit through.
    Bill D
    I'd have to devote time I don't have to confirm this, but I seem to recall that H2 can leak 'through' solid steel. With pressure, molecules are small enough to slip between those of the steel.


    Quote Originally Posted by John Stankus View Post
    The Joule-Thomson inversion temperature is fairly low for hydrogen so the gas would warm as it expands... might be a safety issue with a flammable gas leaking.

    There are definitely safety issues with transporting liquid ammonia
    Quote Originally Posted by Mike Henderson View Post
    This is interesting. Liquid hydrogen has to be kept under pressure to keep it in its liquid state. In transporting liquid hydrogen, some heat is bound to penetrate the tank and warm some of the liquid hydrogen, causing it to transition to a gas. Seems that would cause the pressure to increase but I assume they have a pressure vent that allows some hydrogen gas to escape while maintaining the critical pressure.

    But if the hydrogen warms as it expands, it seems that you could have a runaway condition - some liquid hydrogen would convert to a gas, but that would add heat to the contents of the tank, and that would cause more hydrogen to transition from liquid to gas,

    What's your take on this?

    Mike
    There is more chemistry here than engineering, but first pass says the situation above would obviate the Ideal Gas Suggestion , where PV=mRT (Pressure * Volume = Mass * R ("gas constant") * Temperature. Or, rewritten as PV/T= mR, since the right side is a constant. And for 2 cases (or situation changes), (P1 * V1)/T1 = mR = (P2 * V2)/T2, and get rid of the mR term. If you allow a typical gas to expand (so V2 > V1), then P2 and or T2 MUST change to compensate and balance the equation ---> either P2 decreases, or T2 increases, or some combination thereof. (I'd think in the case of a H2 transporter leaking, P2 would definitely decrease and dominate the equation.)

    Always and forever, except for H and He - clearly NOT ideals.

    The thing saving us from hydrogen annihilation (and helium too) is, I dimly recall, that the Joule-Thomson temperature increase situation holds true near room temperatures and pressures. So, I'd think typical storage pressures and temperatures in the real world might keep us out of the runaway reaction zone. But again, a little out of my everyday calcs.

    I'm certain I'm not Mr. Stankus (pardon the usurpation) and that this is TMI. Slainte Mhaith!
    Last edited by Malcolm McLeod; 05-02-2021 at 9:56 AM. Reason: clarity

  7. #82
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    There are many accidents every year from ammonia leaks, from agricultural use, railroad accidents and in refrigeration leaks. It comes out at such a low temperature that it will freeze human flesh instantly. There's a lot more of it around than most people realize.

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    I used to follow the liquid N truck up the hill to the lab on weekend mornings. Interesting to see the long zig zag of intercooler piping to the pressure relief valve under the frame. c. I was told if it vented at the liquid tank temperature the valve would likely ice open with water ice and not shut off until the entire tank was vented. The cooler did drop small chunks of water ice on the road as it hit bumps in the road. That is basically how they lost a nuclear submarine. Air valves into the ballast tank iced over and they could not blow water out of the tanks to float up. When the sprung a leak.
    Bill D..
    Last edited by Bill Dufour; 05-02-2021 at 3:16 PM.

  9. #84
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    Quote Originally Posted by Malcolm McLeod View Post

    I'm certain I'm not Mr. Stankus (pardon the usurpation) and that this is TMI. Slainte Mhaith!
    Actually, it's Dr. Stankus. My PhD is in Physical Chemistry. I am a Laser Spectroscopist by training. I do teach my Universities Physical Chemistry: Thermodynamics course. (I'm not a Thermodynamicist, but I do teach the Senior level undergraduate Thermo course for Chemistry and Biochemistry students)

    A couple of issues with my earlier off the cuff response. With a little google-foo There is a European Commission funded inititative Hysafe- Safety of Hydrogen as an Energy Carrier.

    http://www.hysafe.org/

    http://www.hysafe.org/download/997/b...on%201_0_1.pdf

    Critical point is 33 K (-240 C, -400 F) 1.297 MPa (12.8 atm, 188 psi) So likely will be in a supercritical fluid state (definitely behaving non-ideally)

    The Inversion Temperature is 193 K (-80 C, -112 F) above which the temperature increases on depressurization. (example in above reference quotes 6 degree Celsius increase with a sudden pressure drop from 20 MPa to ambient. Though it claims explosion is more likely due to electrostatic charging of dust particles during depressurization). Higher pressures and temperatures increase the temperature rise.

    One reference I found spoke of needing to pressurize to 700 bar (70 MPa, 690 atm, 10000 PSI) to get the needed storage density.

    There has been work on using Metal Hydrides for storage that might reduce pressure requirements (this work goes back to the 70s...did a science fair project on it...Mercedes had a hydrogen powered demonstrator bus using metal hydride storage)

    I think my main point, is that hydrogen storage for transportation use is a fairly complex problem. There are non-trivial safety issues that need to be addressed.


    Also, my off-hand comment on Ammonia transport hazards is not meant to minimize the common safe use in agriculture, but rather point out the issues of having large quantities of hazardous materials in dense population areas. An ammonia accident in rural agricultural applications usually only affects the immediate workers and is not in a confined area (concentration can dissipate quickly). In transportation applications you may have confined areas and many people. Look at ammonia based refrigeration accidents.

    Though this being said, thinking about the hazards of having 20 gallons of gas parked in your garage would be an interesting thought experiment regarding safety.


    John

  10. #85
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    The latest and greatest Tesla Model S Plaid has an EPA range of 520 miles and can recharge 175 miles of range in 15 min at a supercharger. Pretty much everyone I know needs to stop for a 15 min break every 2-300 miles anyway, so I think those kinds of numbers (assuming they aren't off by more than 20% or so in the real world pretty much solve my range problem for 99.8% of the trips I ever take. (not to mention 0-60 times under two seconds-- who has tires that good??)

    Granted that particular car is not affordable by mere mortals (heck, you could probably buy two Martin sliders for that price!), but to me it pretty strongly suggests that within ~3 years the technology will trickle down to much more affordable cars and the range discussion will largely fade into the background for most of the population of the country. The model 3 currently will recharge from 10 to 80% in 22 minutes; it won't take too much to push that to be pretty competitive with a gas fill-up.

    The vehicle that gives me range anxiety is my 2007 F350 diesel pickup, with a camper and my organ trailer the range is only about 220 miles and I often find myself in places where I can't get the vehicle to the advertised diesel pump because of its size. I've gotten to a pump running on fumes way more often than I'm happy remembering. I leave the major highways only with significant trepidation. Planning is always required and the Ford doesn't have a slick trip planner to do it for me. Getting in and out of most truck stops in less than 20 minutes, at least in the Northeast where they tend to be very busy, is rare.
    Last edited by roger wiegand; 05-02-2021 at 1:25 PM.

  11. #86
    This is a bit off subject but I recently read a news article about the direction for software in new cars - both ICE and EV. The manufacturers are going to offer software enhancements for a monthly fee. As an example, suppose they put in the hardware for a heated cup holder in the car (to keep your coffee warm). They might charge you $1/month for the software upgrade that makes it work. Not everyone will want that, of course, but many people will. That $1/month is pure profit to the company.

    More elaborate features, like self parallel parking, would cost more, maybe $3-$5/month. The enhancement will be downloaded to the car over the Internet - you just have to connect your car to the WiFi in your home.

    Note that this will be for all vehicles, ICE, hybrid and EVs.

    This is good and bad. It will encourage the manufacturers to keep making new features available for your car. Today, your car is generally what it is when you drive it off the lot. And people who don't use certain features won't have to pay for them - the price of features today is bundled in the price of the vehicle. The bad thing is that you will never "pay off" your vehicle - you'll pay monthly for as long as you own the vehicle.

    Mike
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  12. #87
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    Quote Originally Posted by Mike Henderson View Post
    This is a bit off subject but I recently read a news article about the direction for software in new cars - both ICE and EV. The manufacturers are going to offer software enhancements for a monthly fee. As an example, suppose they put in the hardware for a heated cup holder in the car (to keep your coffee warm). They might charge you $1/month for the software upgrade that makes it work. Not everyone will want that, of course, but many people will. That $1/month is pure profit to the company.

    More elaborate features, like self parallel parking, would cost more, maybe $3-$5/month. The enhancement will be downloaded to the car over the Internet - you just have to connect your car to the WiFi in your home.

    Note that this will be for all vehicles, ICE, hybrid and EVs.

    This is good and bad. It will encourage the manufacturers to keep making new features available for your car. Today, your car is generally what it is when you drive it off the lot. And people who don't use certain features won't have to pay for them - the price of features today is bundled in the price of the vehicle. The bad thing is that you will never "pay off" your vehicle - you'll pay monthly for as long as you own the vehicle.

    Mike
    I'm not seeing it: the price of the "optional" features will still be bundled in the price of the vehicle because the hardware (e.g. sensors, wiring, switches) required to implement them will have to be installed in every car.

    And I'm envisioning conversations like:
    Owner: "My cruise control stopped working."
    Service writer: "Oh, I see the problem...the credit card you used for your subscription expired."
    Nope, not gonna happen.
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  13. #88
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    The recent Tesla car that crashed with no driver Musk stated then driver had not subscribed for the fancier self driving function it just had the basic free cruise control.
    Bill D.

  14. #89
    Quote Originally Posted by Lee DeRaud View Post
    I'm not seeing it: the price of the "optional" features will still be bundled in the price of the vehicle because the hardware (e.g. sensors, wiring, switches) required to implement them will have to be installed in every car.

    And I'm envisioning conversations like:
    Owner: "My cruise control stopped working."
    Service writer: "Oh, I see the problem...the credit card you used for your subscription expired."
    Nope, not gonna happen.
    Here's an article about it from Bloomberg. It's a newsletter I receive via email.
    ++++++++++++++++++++
    Yes, the Porsche Taycan is flying out of dealerships. And yes, it charges faster than a knife fight in a phone booth. But you may not have heard much about the most vanguard feature on Stuttgart's newest electric whip.
    For $474 up front — or $12 a month — Porsche HQ will remotely switch on what it calls the intelligent range manager, an over-the-air software update that limits the maximum speed and tweaks the car’s navigation system to stretch how far it will travel on a single charge.


    The what, in this case, isn’t as interesting as the how. Taking a cue from Tesla, Porsche is finally treating its 5,000-pound computer like the SAS platform that it is. It’s selling a slightly brighter shade of green like a Netflix subscription or some kind of extra swag in a video game. Get ready to see a lot more of this.
    “It’s a subscription world and we just live in it,” says Karl Brauer, executive analyst at iSeeCars.com. “There could be dozens — even hundreds — of unique capabilities that you may or may not have soon, depending on what you pay every month.”
    Most major automakers are fleshing out a strategy for selling upgrades via over-the-air software updates and a rash of them will start popping up in the wild in the next few months, starting with luxury vehicles. “If you don’t have digital experiences, you are not on the radar screen,” Kjell Gruner, CEO of Porsche Cars North America, recently told Bloomberg. “You’re irrelevant.”
    Audi, BMW, Lexus and Mercedes all confirmed that these options will appear on flagship vehicles soon, though nearly all of them said, via e-mail, that it was too early to discuss details. It’s “part of a global BMW strategy,” said spokesman Phil DiAnni. “When and how the concept gets rolled out in individual markets, and to what extent, is still to be determined.”
    General Motors is all-in as well. On Friday, some 900,000 of its vehicles in the wild got an over-the-air version of Maps+, an app-based navigation tool. Similar software pushes are in the works for the company’s Super Cruise autonomous driving function. Underpinning it all is a massive electrical hardware update launched at the end of 2019. Dubbed the Vehicle Intelligence Platform, the system can process 4.5 terabytes of data per hour, a five-fold increase over its predecessor.
    In truth, GM and its rivals are treading a somewhat fraught path. While drivers are used to paying monthly fees for music, movies and free-shipping, subscriptions for seat warmers, active-safety features or efficiency measures may take some getting used to by the sweaty masses.
    Indeed, BMW has already learned some hard lessons about what may, or may not, fly in the automotive cloud. In late 2019, the company walked back an $80-a-year fee for Apple’s CarPlay after getting throttled on social media. More recently, the company has incited some more sporty Twitter debate with its smart high beam feature, another software-enabled subscription. “Hostageware” quipped one critic. “Cars are like printers, just W-A-Y more expensive,” wrote another.
    “You can easily see a major backlash to all this,” said Gartner analyst Michael Ramsay. “ And guess what, they’re probably going to have to walk back some of these other things they’re playing around with.”
    Still, as the auto industry refines a new way to sell it’s also coming up with new things to sell, including a range of features that have never been on a vehicle (think: programmable ambient lights, automated driving features and technology tricks to idiot-proof the humbling act of backing up a trailer).
    Ramsey, who helps car companies craft their tech strategies, has a simple rule: just because you can, doesn’t necessarily mean you should. For now, manufacturers should focus their software upselling on things that aren’t normally expected in a vehicle, features that have value only at certain times and/or personalized touches. Possibilities include a traction algorithm for people who drive on snow a lot, climate-controlled cupholders and advanced analytics to log certain trips, say, for someone who travels for work and expenses her mileage.
    A few of the features BMW currently has on offer remotely fits Ramsey’s criteria nicely. They include real-time traffic alerts and a drive recorder, which records a 40-second loop from the front of the car and can be used to replay an accident.
    Crusty consumers aside, the rewards on over-the-air options appear to outweigh the risks. Not only will over-the-air updates provide a healthy revenue stream, they represent a strategic coup, shifting the decision on expensive options away from dealership salesman and extending it indefinitely. The potential to upsell a swanky feature will improve every time an owner gets a raise, every time a vehicle changes hands on the used market.
    Morgan Stanley reckons that Ford Motor’s cloud computing foray, including digital subscriptions, could one day be a $100 billion business, roughly three times the company’s current market cap. That’s right: Ford Software = (Ford Motor x 3). The math is relatively straightforward: $10 a month from the 75 million Ford’s on the road adds up to $9 billion a year — and an extremely profitable $9 billion a year at that.
    Here’s the takeaway from Morgan’s team of auto analysts: “We believe the industry is in the early innings of a profound shift to securing revenue measured in data, derived from its hardware ‘real estate’ and monetized through a range of recurring business models.”
    Every automaker is doing similar math at the moment, giddily crunching what the Silicon Valley software set calls “multiples.” However, if they are ham-handed with the cloud, they might not sell many cars at all.
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  15. #90
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    [QUOTE=Stan Calow;3118072]There are many accidents every year from ammonia leaks, from agricultural use, railroad accidents and in refrigeration leaks. It comes out at such a low temperature that it will freeze human flesh instantly. There's a lot more of it around than most people realize.

    Train derailments involving ammonia spills are actually rare. I might have overlooked something but my search came up with 2003 as the most recent derailment involving ammonia.

    Being a common industrial cooling medium it stands to reason that it would also be the least regulated systems too. Any transport method has to meet DOT standards. Whether by rail or by road. The nurse tanks used in ag are also DOT certified. After doing some searching it appears the majority of leaks have occurred at large storage tanks (Ag use) where they refill smaller tanks for field application or at facilities using ammonia in refrigeration. I also saw it's used as a dehydration agent in some food processing. So after looking there are more incidents than I thought but most are not related to transport.

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