Promising development for Electric cars

[ShneekeyTheLost]

Article

You see, this is the kind of thing that has been cropping up ever since electric vehicles started really hitting the market. Charging stations have been cropping up all over the place. To directly quote the article:

“There are now hundreds of plug-in vehicles throughout the state, and the addition of quick charging allows customers to fully recharge cars while they take a break to shop and dine,” said ESN President & CEO Paul Mitchell. “It’s exciting to see leading global retailers offering this advanced new technology to their customers.”

And, of course, Walmart of all places is leading the pack. Not that it is surprising. If it takes you a half hour to charge up your vehicle, that means you are more likely to browse, window shop... and hopefully impulse buy. And hey, you're gonna have to go get groceries anyways, right? So why not charge up your car while you are waiting in those infamously long Walmart lines?

So how is that for convenience? Even less hassle than the pump these days, just plug in and go shopping. And, of course, if this project is successful, you'll start seeing them pop up at Walmarts all over the nation... maybe even one near you.

Of course, this is only going to be even more explosive if people actually start driving electric vehicles. See a need, fill a need, after all. Imagine how many electric cars are actually out on the road right now, and they've got this many charging stations up and running. Now imagine how many there would be if even one in ten were electric vehicles...

[Atomic]

On the other hand, Nitrogen cycle engines have solid potential and are do-able now. It's just getting the infrastructure (refueling stations) set up. Liquid nitrogen is 1/10 the price of milk (see article) because it's a leftover product from making liquid oxygen, argon, and other common industrial gasses. And -- no battery leftovers to dispose of!

Air cycle engines are becoming, well, not uncommon in India for example, running on compressed air for small commuter cars. Nitrogen cycle engines are just a step away from what is being produced now.

The only drawback I can think of is having the Dewar tank boil down gradually over long parking times -- weeks maybe, but a tiny price to pay for something essentially pollutionless! And, isn't that the point?

[Dave]

The only drawback I can think of is having the Dewar tank boil down gradually over long parking times -- weeks maybe, but a tiny price to pay for something essentially pollutionless! And, isn't that the point?

Ventilation of vehicle storage areas would be an issue. The nitrogen slowly boiling out of the tank would tend to displace oxygen from the air, in any enclosed area with poor air circulation. Somebody who walked into (e.g.) a well-insulated, weather-sealed home garage, where the car has been boiling out nitrogen for a week or so, might go into anoxia and pass out before s/he knew anything was wrong.

Public garages shouldn't be a problem... if they're open enough to exhaust away the residual CO and CO2 and hydrocarbon fumes from gasoline-engine operation they'd probably have enough air exchange. Driveway or street parking would be fine.

As to the cost of LN, and it being essentially free as a side-product - remember, that was the original rationale for using gasoline - it was a waste product of kerosine production. If LN becomes a highly popular energy-storage medium for automotive transport, you can expect to see the cost climb sharply just as soon as the demand exceeds the "side product" supply. At that point, the marginal cost will be no less than the free-market cost of the energy needed to run the additional refrigerators/liquifiers.

Similarly, it will be no more and no less "pollutionless" than the use of mains electricity to recharge electric-car batteries - the pollution will be that of the original generation system, whether fueled by coal or natural gas or hydro or nuclear. As with electricity, the pollution generation will be localized (at the power plant) rather than distributed (in millions of engines) and might be easier to manage and contain.

It certainly would be a good well-distributed defense against T-1000 Terminators!

[Fairportfan]

Actually, the main problem i see with LN2 motors* is that you're drawing the heat to run the motor from the air.

Many years ago - maybe as far back as the 1940s - somebody was producing model engines that Model Railroader magazine staff called "dead steam engines".

They were model steam engines with actual cylinders that were driven by CO2 from dry ice sticks in the locomotive boiler and/or the tender; they had a throttle that was controlled by a small electric motor that was driven by electric current applied to the rails to open or close it.

They operated fairly well to start - but before too long, frost began forming on the outside of the boiler/tender, and the locomotive began slowing down, because not enough heat was able to transfer into it to vapourise more of the dry ice.

Power is power - doesn't matter what form of engine or motor you're driving the vehicle with, it takes the same amount of power. And i can't imagine a practical car that could have enough heat-transfer surface to pull enough heat into the system from the atmosphere to produce sufficient sustained power to drive a car.

EDIT: I hadn't read the article before i made that post - the process as described involves getting the heat energy from water injected into the cylinder with the LN2. I'll still believe it when i see it - because now you're getting the heat energy from the water, and there's a lot less energy in a litre of water than you get from burning a litre of gasoline.

And what happens in cold or sub-freezing temperatures?

==================

*"Motors", properly, not "engines", because they are converting energy produced elsewhere, not generating their own, as internal combustion or steam engines do.

[Atomic]

The trick of injecting a water/methanol mix serves two purposes. The methanol keeps the water from freezing immediately, and the water's huge latent heat (even at freezing temperatures) triggers a vaporization cascade in the liquid nitrogen. Basically, any liquid to gas transition means an immediate volume increase of 700-800 times. That is, 1 gram (cubic centimeter) of water, for example, at 100C, boils into nearly 800 cc of water vapor (steam) at 100C, at the same ambient pressure. This is why SciFi ray guns that make people disappear omit the fact that 80Kg of water in the body would become 80x800 = 64000 liters == 64 cubic meters of steam, instantly. AKA, Steam Explosion.

It's too late at night to look up and do the specific math, but a quick look shows a 10:1 (more likely 50:1) LN2:H20 mix would work fine at any above anti-freeze mix liquid temperature (-40C -ish), so this would work except for extreme Ant/Arctic conditions.

For more on Latent Heat and Silly SciFi science, here are two things I wrote up back when I was teaching this stuff.

Latent Heat - General
Latent Heat - Physics

Yes, I'm still weird, and proud of it. Nyah!

[Fairportfan]

Yes, i know about latent heat.

And i know about steam engines (which this basically is).

And i don't think there's be enough latent in any practical amount of water to do the trick in Real Life.

Please provide any links you may have to not-too-technical writeups that actually explain how this works.

[jwhouk]

The biggest problem with pretty much any new engine design for cars is, will it work in a temperature range between -20 to 120 degrees F (-30 to 50 degrees C). That's the typical seasonal temperature range of most of North America.

It's also one reason why I've had some skepticism about electrics.

[Julie]

Meh...old news. My local Kroger put in two parking spots with charging stations months ago...which is good because I avoid shopping at Wal-Mart whenever possible.

Which is even funnier when you consider I worked there a summer in college and also was in a nationally aired commercial they did...which was arguably the best paid job I ever had after the royalty checks came in...