Zizz!


#1

Will super flywheels ever be a good energy source for cars or anything else vs accumulators?-Kevin


#2

Last I heard of flywheels for energy storage, they were still having trouble getting a large enough flywheel to spin at a high enough speed without flying apart.

Back then IIRC they were using carbon fiber and/or kevlar. Maybe nanotubes will breathe new life into it.

Still, I have this mental image of a super-strong flywheel somehow getting out of its container, spinning at 100,000 RPMs, skipping down a sidewalk bisecting pedestrians for a couple of blocks before exploding and raining shrapnel on a group of school children waiting for their bus.


#3

Yes the Physics would probaly dictate a need for “unobtainium”-Kevin


#4

How about depleted Uranium? That should send consumers flocking to the showrooms…

Flywheels and accumulators are not a source of energy. They merely do a poor job of storing energy and will never see widespread application…Neither will hydrogen fuel cells, for the same reasons…


#5

Maybe a flywheel Hybrid?-Kevin(Of course one has to spin a flywheel up and charge an accumulator before they become an energy source ,every energy source is powered by something according to the law of entropy)


#6

Doesn’t the Honda system use the flywheel as a stator to generate electricity and then in reverse electrically to boost the power of the small engine?


#7

I remember this on the cover of Popular Mechanics or Science, what, 30 years ago? In addition to the problems mentioned, wouldn’t there be immense rotational forces? That would seem to put a lot of stress on the vehicle.


#8

Texas, I was going to mention about seeing these stories in those mags. 30+ years ago and add those mags have made many false predictions. Aren’t we all suppose to have flying cars by now?


#9

I don’t see how a flywheel could be used to power anything. It makes for a good energy reservoir in some situations, like wood chippers, but a law of physics known as conservation of energy dictates that energy must be put into the flywheel to rev it up before it will do anything, and given that nothing is 100% efficient, you would lose some of the energy to friction, etc…

Also, if a flywheel with a really significant energy capacity (that is, fast-spinning and heavy with a lot of weight out at it’s circumference) were placed in a car, it’s angular momentum (gyroscopic reaction) would create some nasty vehicle dynamics issues.


#10

Keep it in a vacuum chamber on magnetic bearings.

Mount the whole assembly (probably including the strong, probably heavy, shrapnel-resistant casing) on gimbals to get around some of the gyroscopic effects.

The insurmountable problem is the materials you make the flywheel itself. IIRC from the PopSci/Mech articles, in the 90s they had a tendency to fly apart at around 35000 RPMs, and they need to go up to several times that.

I don’t think it’s going to happen any time soon, anyway.


#11

Good replies,but it seems to me that it could probaly be made to work better then say springs or compressed gases-Kevin


#12

Maybe it could work better, but springs and compressed gases are much more practical.

For around $380-$400, you can get a hell of a good air compressor at the Home Despot, and good quality air driven tools are not terribly expensive. Just run it for 1/2 hour with the drain cock open to break it in, hook up a hose and you’re good to go.

Clocks have worked well for how many years on springs or suspended weights with a fairly simple (and very effective) pendulum or spring regulated balance wheel.

Why deal with magnetic bearings, vacuum chambers, and shrapnel-proof casings when other alternatives are so much easier? A flywheel, no matter how good will not provide it’s own energy. It can only store energy that has been put into it, and as that energy is used, it has to be replenished.


#13

As do the rest of these devices,what I really want is a augmenter.This can be a very interesting thread.Near where I live is the worlds largest pumped storage facility,I suppose you could say it was a Hybrid system of sorts.It uses excess generating capacity to pump water uphill during times of low demand for electricity and releases the water to turn the motorgenerators at times of peak demand to eliminate the need to throttle the power plants or build additional ones.I say hybrid because gravity actually powers the turbines in the generating phase.Anyway Hybrids using whatever power system makes perfect sense to me.What suprises me is that,I have never heard of any homeowner using a small scale pumped storage system(of course this is unrelated to cars unless you use the current to charge an EV-Kevin


#14

“Neither will hydrogen fuel cells…”

But they are used successfully in Scandinavia without burning an ounce of coal, oil, or gas. These folks use hydroelectric plants. There are 7 refueling stations in use, 1 under construction and 8 in evaluation in Norway, Sweden, and Denmark. They aren’t on every street corner, but the Scandinavian Hydrogen Highway Project is growing.

http://scandinavianhydrogen.org/


#15

Clocks are very low-power devices.

I’d like to see you run a car off nails and a potato.


#16

It’s still less energy efficient than battery electric.


#17

I’m with Caddyman.

Flywheels are not energy sources, merely energy storage devices. And because storage of any substantial amount of energy requires an amount of mass that makes its own frictional problems (think bearings), and using their stored energy then requires more energy to overcome the used energy and keep them spinning, they’re not even a great storage device for most applications.

The one in your engine is actually only there to smooth out the engine. The energy in your crankshaft comes in pulses as the piston power strokes happen. The flywheel stores some of that energy and re-releases it to overcome some of the resistances that the crankshaft faces between those power pulses. You have a harmonic balancer (also often called a damper) on the front of your crankshaft with a piece of rubber in it that essentially does the same thing. Your flywheel also serves as a ring gear for your starter and a frictional surface and mounting platform for the clutch and flywheel respectively (or a mounting platform for the torque converter), but its flywheel function is simply to smooth out the crankshaft.

Whenever I read about new ways to power a car I always try to identify the energy origin. With the exception of solar powered cars (not yet practical), it always has to be added from the outside as gasoline, diesel, LNG, electricity, cooling grease, ethanol, or something else. 100% of all the enrgy used for the car, whether it be for motion, lights, heat, or running the radio, all has to come from that fuel. Retreival and regeneration systems all just contain ways of storing some of the fuel’s energy at the onset and retrieving it later. Regenerative braking systems just recover some of the fuel energy that was originally converted to inertial energy in the car. The create no energy whatsoever.


#18

Chemical fuels are just an energy storage device, too. It’s ALL solar.

And friction isn’t the limiting factor on flywheels as an energy storage device, it’s tensile strength. The discs fail WAY before the bearings do.


#19

True, but I started my chain of events at the car rather than the sun’s core…

I was alluding to the loss of the stored inertial energy through friction rather than failure of the discs. That’s the main problem with flywheels of any significant size, the main reason they “spin down”. Magnetic and air suspension systems alleviate much of this, but they’re not really practical for most applications. Bottom line: you got to keep putting energy in to keep the thing spinning, and if you remove some inertial energy from it to move the car along, you got to replenish it…and all of that comes from…okay, the sun’s core.

Remember when drag racers used to sit on the “pumpkin”? A few of the early drivers became the victims of that tensile failure before scatter shields were implemented.


#20

Consider the gyroscopic effect that could perhaps be harnessed helping handling. Think too that any failure at even the smallest level could result in an out of control vehicle at the worse time. I’ll pass.