Mechanical Energy Storing Device

Pumping water to a tank (a very high tank), does the same thing, but without nearly as much friction losses. Also, can you even imagine the size, weight, cost or complexity of the spring involved?

I think it would cost a lot less than a water tower for the same amount of energy storage.

Not hardly. A water tower is basically just a tank with legs on it and from a manufacturing standpoint pretty simple and easy to manufacture.

Gigantic springs, flywheels and gearboxes on the other hand are very expensive to construct and maintain.

Not really, water is much cheaper and easier to handle than any kind of mechanical contraption that has mass, moves, and has bearings.

There are other means to store mechanical energy; in addition to the flywheel and pumped storage mentioned in this thread there's also compressed air/CO2 in very large underground caverns. Unfortunately the amount of energy recovered per unit stored rarely exceeds 67% for most of these devices.

Your goal, should you decide to accept this mission, is to design an economical device that exceeds 90% end-to-end efficiency. This tape will now self-destruct...

Mechanical energy storage has friction losses when storing the power, and friction losses when releasing the power. There are other losses as well, for example, flywheels have friction losses while HOLDING the power, and springs slowly distort while under load, so a clockwork system will lose both held power AND maximum capacity to spring distortion.

Water-based energy storage is generally more efficient than spring/clockworks, because water storage does not lose energy while holding, except for evaporation, and the water does not experience much friction loss while traveling through the pipes from pump to reservoir, or from reservoir to turbine. The pumps and turbines have their own friction losses, but those are independent of the energy storage system, whether you hook up a generator to a water turbine, a flywheel, or a clockwork spring, the energy lost within the generator is the same. But the energy lost within the flywheel, water turbine, or spring will vary.

Yes, that would be what I was thinking, too.

These "flywheel" storage units are almost mainstream now.

the biggest drawback to a Flywheel is:

1. Its weight
2. and just as, or more importantly is it gyroscopic effect

Google "Dinorwig Pumped Storage Scheme".

Cool WIKI article. Thanks!

I've been meaning to add...

A very similar plant, also commissioned in 1984, here in California: https://en.wikipedia.org/wiki/Helms_Pumped_Storage_Plant

as your spring is winding up it will have greater resistance and will just stop storing energy, you really didn't think this through

Design the right size spring. When it gets to the desired deflection, stop winding. It will be a spiral spring like used in a clock.

"Excess" power is not produced during the day. It is produced at night, when people are asleep and not working. Wind and wave power are rather constant, but don't produce much, overall.

Pumped storage is the cheapest and most proven energy storage method in the class you describe.

As noted, as spring tension rises, so does the power required to increase it further.

And have the world full of radioactive spent rods for the next 50000 years.

We've had this argument before, and it's like arguing about the best NFL team, with you saying it's the Bears⁽¹⁾ for their offense, while I'm saying it's the Bears for their defense.

So rather than bring up the whole mess again, I'll just say that Thorium is a better fuel source, based on my research (which makes it only barely stronger than in my opinion), and leave it at that.

https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor

Notes:

1. Don't care about football one way or the other, but since I'm from Chicago, I use the Bears as my default example.
   

Da Bears

And the new molten salt reactor design by the MIT grads, is regarded as highly fail-safe, can run on "spent" fuel, can run on essentially unenriched fuel, etc. Too bad this technology was not the centerpiece of the Iran nuclear deal (since we all know they only want enriched uranium for domestic power production)...wink, wink, nod, nod.

The only kind of power the Iranians will develop will be domestic to the nations where it is delivered all in microseconds.

"Too bad this technology was not the centerpiece of the Iran nuclear deal (since we all know they only want enriched uranium for domestic power production)...wink, wink, nod, nod."

That's the same reason Thorium wasn't pursued in ANY post WWII nuclear power plan: You cannot weaponize Thorium beyond the crudeness of a 'dirty bomb' (a conventional bomb surrounded with nuclear, biological, or chemical material. Upon detonation, the bomb scatters the surrounding material far and wide, contaminating a large area), so everyone in power decided that Uranium was a 'better' fuel for the nuclear program.

The fact that uranium reactors could enrich low-grade uranium into 'weapons grade,' and even produce quantities of weapons-grade Plutonium, was an idea that never came into anyone's mind. (I think I need to towel off, I'm literally dripping from the sarcasm needed to type that last weapons-grade Balonium sentence with a straight face.)

One 'downside' to Thorium reactors is that they are not self-starting⁽¹⁾, they need some U-238 to be the 'lit match' to start things up, and U-238 is extremely rare in nature. However, you can extract U-238 from a running Thorium 'breeder' reactor, or from many Uranium reactors, so its scarcity in nature isn't an issue, since we don't need 'natural' U-238 to start things up.

Notes:

1. That's also one of their safety features, they are 'self-quenching,' if left on their own, they will cool down instead of melting down.
   

I don't think you were hearing me. These new molten salt reactors can run for about 30+ years (depending on the fleet constructed) on just the "spent" uranium fuel from conventional reactors. Even after that, they do not require enriched uranium, nor do they require Thorium (but would probably work just fine on Thorium), or any other suitable gain fissionable fuel.

Oh, I think we were talking about slightly different models of Molten Salt Reactors.

Sorry for the confusion.

(Although with all the Thorium we pull out of the ground while mining for tin, which the mining companies have to treat as 'hazardous waste,' due to current government regulations, it would seem logical to pursue a plan that could turn that 'hazardous waste' into 'valuable resource.' I'm sure the mining companies would love to trade those shipping containers of Thorium for some crisp, green dollar bills, instead of having to SPEND dollar bills to contain and re-burry that stuff.)

I think you mean U-233, not U-238.

One of the least complicated mechanical power storage systems I've heard of is a set of heavily weighted cars on rails built on a hillside. When excess electrical power is being generated it is used to run a winch and cable which pulls the cars up the hill.

When the stored power is needed the winch is converted into a generator that produces electrical power as the cars proceed down the hill. A controlled descent of course.

A hydraulic based system is already being used by the TVA. Excess power is used to pump water into a high reservoir and then used to power generators like a standard dam when needed.

Hooker

I'm thinking of a residential application.

Spring-based residential energy storage?

Unless you're used to living 'off the grid,' you'll find the average house uses considerable power, and a spring-based energy storage system would likely take over the entire property, surveyor line to surveyor line, before it even got CLOSE to providing enough energy for the house its crowding off the lot.

Or at least fill the entire 3 car garage with tech. mech. trying to power the house with a clock spring mechanism that is larger than Big Ben!

Larger than the Bell? Oh it's MUCH larger than the bell. I'd wager it'll be larger than the entire clocktower over the parliment building.

Didja ever look into how a grandfather clock works? The suspended weights work with the swinging pendulum which is attached to the escapement which regulates the release of energy from the spring mechanism which moves the hands...And guess how the energy gets into the spring, via human muscles doing the winding.

In other words the falling weights do not power the clock, they merely help the pendulum overcome friction and meter out the energy already stored in the motor. Think about it, please, otherwise a grandfather clock would be a perpetual motion machine.

Did YOU ever look carefully at a grandfather clock, or more than one?

https://www.google.com/search?q=falling+weight+grandfather+clock&tbm=isch&imgil=ltlrTFK751

In some (fake) wall- and grandfather clocks, the weights are only for looks, and these clocks will either have springs or an electric mechanism. But in true Grandfather Clocks, there is no place to insert a winding key, because there is no wind-up spring. The falling weights are the only source of energy.

Please explain how the weight that moves down gets back to the top after it reaches the bottom. Clearly you have never owned or fixed one. If you tell me that it simply reverses because after all, there's now a weight at the top ready to repeat the cycle, then I have a bridge that I'd like to sell you.

Here's a good explanation, complete with pictures, and here's a Bulova instruction manual; please read the bottom of page 5, titled "Winding Your Clock".

Again, we are not talking about movements with spring drives. I'm talking about movements that are gravity driven with weights and it requires human intervention to raise the weights to keep the clock movement operating, just as a spring driven movement requires rewinding.

This Clock, not the spring driven style.

Hooker

That's why the chain has a loop on the opposite end from the weight! So the owner can pull down on the chain(s) to lift the weight(s) back up. There's a ratchet mechanism so the chain does not rotate the spindle backwards while lifting the weight.

What is your explanation of how the weight gets lifted?

From your Bulova manual, the page 5 you refer to:

and

Although the manual uses the term "Winding", there is no spring involved (except the springs in the ratchets). The process of "winding" is simply lifting the weights. If the weights are suspended on cables, then those cables are indeed wound around a drum.

The kind of clock I was thinking of uses a chain (page 10 of the Bulova manual), and the chains do not wind around anything (they make a 180° turn around the cogwheel and go down the other side), yet they still provide the power to run the clock, and Bulova still uses the term "Winding" for the operation of lifting the weights.

nowadays dropping weight drives a generator and provide light.

And what happens when the weights hit the limit of their down travel????

C'mon now. I wasn't born yesterday. I've worked as a mechanical engineering tech and mechanical design engineer too long to buy into that kind of explanation.

And, yes, I have seen the clocks with the wind up key. That's not what I'm talking about. See dk's post above.

Also, the pendulum is nothing more than an adjustable regulator to speed up or slow down the clock.

Dave G.

Having grown up with a real grandfather clock, I can say you are both partly right and partly wrong. There is indeed a key to wind it up, but it doesn't wind up a spring. It raises the weights.

There is no spring. All the energy comes from the weights, and the pendulum regulates the release of the energy, one tick at a time, as the weights slowly descend for a week. It was my job to wind it up again so the weights were at the top.

If you've ever heard of an eight day clock, that's a clock that takes 8 days for the weights to hit the bottom of the weight compartment.

<sigh> The grandfather clock I'm talking about requires one to pull down on the unweighted end of the chain to raise the weight back to the top.

But this is getting beyond picky so I'm unsubbing.

Hooker

Not being picky. The one I used did have a key, but the principle is the same. The energy came from weights, and the pendulum regulated the release of the energy through the escapement. I was not aware that there were clocks with chains or cables to pull the weight back up until I saw them on the google search (and by then it was too late to edit my post), but that don't make no nevermind (to quote my grandfather) about the source of the energy.

Again different styles of clocks, but the energy does not come from the weights themselves, it comes from the change in potential energy when the weights are raised by turning a crank via human muscle power. The weights merely convert the potential energy into kinetic energy as the weights slowly fall. There are no free lunches in the real world of energy conversion.

On the other hand I was always fascinated by the rotating pendulum clocks (Atmos) that were "perpetually powered" via changes in the atmospheric pressure and temperature.

Bore some deeep holes in the ground, and put some weights that will be lifted using power available, then generate needed power by lowering the weights. That will be sort of like your grandmother of all clocks.

Kind of weak punchline there, I would have called it the grandfather of grandfather clocks.

(I know you were going for the 'Mother of all <blank>' punchline, but it doesn't quite fit like that, in my opinion.)

As I and others have pointed out just do the numbers on the basic power usage of a typical home and you will see why a all mechanical spring type system would not be financially cost effective in any way.

You would need a system the size of a small bus weighing several tons and costing many tens of thousands of dollars to store the same working energy that a common 12 volt 100Ah deep cycle battery that can be purchased for ~$100 can do.

I did just that, and hooked up a 10- speed bike to an exerciser friction wheel, changed out the "resistance fan" for a sheave (about the same size as the sheave on an older generation alternator (for the old Chevy S-10 pickup line), and connected a medium capacity 12 V lead acid battery. Low-tech, but absolutely works every time I feel the energy within me (which is not often) to pedal. Also bought an 800 W inverted to power some of the useful things (just not enough for my metal lathe).

I think for large scale storage the others are right. Pumping water, compressed air, or weights are better. However, I've thought about using springs for small scale storage. Suppose you had a bicycle with a brake lever that engaged a spring to store energy, for example when you are coming to a stop sign. Then when you start up again you engage the spring with the wheel and it gives you a boost. It will release almost the same amount of energy that it took to stop. It could all be done on the front wheel so it is simple and separate from the gears and brakes on the rear wheel. But it might still be heavier than using a battery-operated electric booster.

You might also use it on cars that use internal combustion engines. Some of them turn off the engine now when you come to a stop to save energy, like Prius engines do. Then it starts the engine instantly when you step on the gas again. Maybe you could use a spring to save the energy and then use it to start the engine again, instead of an electric starter. Probably still heavier and less efficient than just using the battery.

On the plus side, if the car battery died, it would be nice to be able to start the car by sticking the tire iron into a hole in the casing and tightening the spring until it had enough energy to start the car. Anyone ever start a Model T manually?

I thought they tried high speed flywheel tech on some early "hybrid" cars!?

https://www.youtube.com/watch?v=n9fAnjgR8lA

You mean like this?

YES... exactly what I thought!

Oops, forgot the reference. Clever, this is attached to the rear wheels of a FWD vehicle.

Another device has a weight attached to a rope wound on a wheel above.When the weight descends slowly it rotates a generator to power a lamp.

Think about the amount of energy stored in current spring-based systems. A good clock will run about a week on one winding, but a very similar clock will run for months on a single AA battery. There is very little energy involved in either, but the battery wins!

Battery doesn't store mechanical energy but chemical energy.Electrical energy is stored in capacitor.

I said nothing about what kind of energy, other than stored energy. If a more efficient method is found to store energy, it can always be converted (minus losses) from one kind to another.

I store all my energy here...

"How much fuel is in there, Cletus?"

"I don't dunno, Jim-Bob, let me light a match and look down the spout. Oww! Dang, I dropped the match in there."

(Sorry, we had ... something happen recently, not gasoline related, but I still needed to vent some frustrations about the person/people involved. And yes, I meant to use a double-negative in Cletus's speech.)

This is the mechanism needed just to move the hands on Big Ben.

Big Ben does not have hands, it has a clapper.

Big Ben is the Bass Bell in the Clocktower over the Parliment building.

What you see here is the mechanism to move the hands on the Clocktower faces.

This is one of the reasons the French are so snooty with us: we can't even use the right name for famous landmarks in our allies' countries.

By the way, that big beautiful bridge over the Thames with the giant towers is the Tower Bridge, not London Bridge. London Bridge is a simple, unimposing modern- style bridge a bit downstream from Tower Bridge. (or is it upstream? I forget.) Oh, and you pronounce Thames as 'Tames,' like 'he tames lions for a living.'

(Sorry for being snippy, been one of those days, had to deal with an Incident early in the day, then, at the company luncheon, the food was half an hour late in arriving.)

Hmmmmm..... I see hands on the clock face!

Yes, those are the hands on the face of the Great Clock of Westminster, the clocktower over the Parliment building.

Not visible: Big Ben, the Hour Bell of the Great Clock of Westminster:

http://www.whitechapelbellfoundry.co.uk/bigben.htm

Technically, it appears that you are correct. I've always known (for around 60 years) of the name Big Ben referring to the clock, not the bell. The first item that comes up on a search for "Big Ben" is this:

The main image is part of the clock face. you have to look closely to see the image of the bell.

I'm talking about the clock tower. I could care less about the semantics of what Big Ben is.

<unsubscribes>

If you really wanted to store some energy (safely), have you done any calculations or looked at the way work pays out from a loaded coil spring? Not so great. You would be much better served with pumped elevated water storage, or compressed air - even though air pressure has its own hazards, that is still way safer IMHO that attempting to engineer a substantial coil spring energy storage device. Heck you would even be better off with stones and a bucket elevator and hoppers.

Hey Papadoc: What ever happened to the collegiate fence building contest in Texas?

I heard the Red Raiders finished first - a bull tight, horse high, hog proof 4-strand classic barbed wire fence with cedar posts.

Longhorns came in second with a green-energy electric fence, but they got run over by the bull.

The Aggies never came in....they could not figure out what to do with the dirt from the previous post hole (they were doing some precision digging, and did not want a dirt pile around the posts), so they just kept going, last report they were leaving Arkansas for Missouri.

Us Aggies have the right principles, if you are going to be insulted, get the F--- out and fight later on a level player field.

LOL - that's the spirit!