Mechanical Energy storage

[Gwydion Forge]

Hello everyone,

I am new here and hope this does not get sent to the Newbie page...but here goes.

I am a 34 year old college student just starting with aspirations of an engineering degree.  Because I have only just started, I don't have the math or physics to solve a problem I have thought up.  I would appreciate any help anyone here can provide.

This is not a problem for any of my classes, just an idea rattling around in my head.

I want to store energy mechanicly using a clockwork system.  I want to use whatever available energy I have acess to (wind, wave, solar or river) to pump water up into a large container.  The container will be set up in a scaffolding so it can be raised before it is filled.  After it is full and heavy, I will let it descend slowly pulling a chain attached to a gear system that will turn the slow but high torque descent into a high enough RPM to run a generator.  

The plan is to take advantage of inconsistant wave, solar, or wind power by condensing it into the storage system.  The problem is I don't know how much weight I would have to lift to generate electricity for a small home.  

To make sure I have listed my idea correctly here goes again.  I want to use water as a ballast in a clockwork generator system.  How much weight do I have to lift to generate power for a small home.  I know from my physics class that there are formula for converting the potential energy of my ballast into KW of electricity...I just don't know how to do it myself.

I eagerly look forward to any replies!

Thanks,

Drew,

GwydionForge

[zeusmorg]

 Hmm, some thoughts on your idea.. lifting a sufficient weight high enough would require massive torque,, so what if you had several containers,, one in action, one empty at the top, and one expended at the bottom?

 That way you could just pump the water up to the empty container from the one at the bottom..

 As far as how much weight it would require to "run a small house" that's about like how much seed does it take to seed an avg yard.. some people may thing that yard is two acres, others .. 50 sq ft..

 1 watt-hr = 2655.224 pound-force foot = 3.670978e+007 gram-force cm.

So, in a nutshell, it's gonna be heavy!

By the way those figures do not consider losses in your machinery and power conversions.

Don't stop dreaming. ( I got accused of killing a dream once)

[wdyasq]

I perfer to kill dreams with the truth .....

By my math a kilowatt hour of electricity is 2,647,058 foot pounds energy. That's lifting a D9 Caterpillar Tractor with rippers and an angle blade about 25 feet in the air. With some of the most expensive electricity in the US, I pay almost a Quarter for the energy to do that.

The infrastructure cost to supply energy in small amount, as used in a household (smaller than ... say AlGore's), is usually much larger than any part of the system. This is one of the many reasons 'grid-tie' systems are so inviting. The bad parts are, In My Opinion, much worse than the benefits of a 'grid-tie only' system.

Be careful of how you build a system.

Ron

[Gwydion Forge]

Ok, So powering the entire house is unreasonable, How about just powering some equipment in the house?  How much would I have to lift to run a fridge for a day?

I had been thinking of using barrels set up in a series like the pervious reply, where one set would be falling full, while another was rising empty.  

Thanks for the rapid replies, keep it comming and I will keep thinking!

Drew

GwydionForge

[TheCasualTraveler]

     If you want to store energy, but not using a battery, it's probably better to bypass the whole clockwork thing and just put the water in a large reservoir uphill from your generator, and then use an efficient micro hydro. And to power a house you would need more than a large container, more like a large pond or small lake.

     Who was doing this last year? I think it was someone from down under. I remember the aerial pics of his pond and house site.

[zeusmorg]

 Storing energy for later use can be done in any number of ways. The lead acid battery for small scale applications is probably the most practical , but definitely not the only way!

 Hydroelectric schemes (like in the earlier post) have been used successfully where the geographical region allows it. There is one in Tn.

 Converting to hydrogen then either burning it as a fuel or using a fuel cell...

 As far as figuring out what can run how much.. nope that I'll leave up to you, you're in college, you should be able to do the math by now! If you can't I'd opt out of engineering...

[spinningmagnets]

I'm fond of "Rube Goldberg" contraptions that might be overly complex, but if its made from fairly free junk and "sort of works", why not?

I don't see any reason it wouldn't be possible to take something like the old farm high torque/low RPM water pumping windmills and have it wind-up a large watch-style coil spring. When it reaches a certain number of turns, it trips a latch, and the spring unwinds fast enough to generate some decent battery charging.

If an hours worth of sporatic wind gave you 5 minutes of charging, the cost effectiveness would be an equation concerning the free-junk/spare-time/patient-wife ratio.

If you have a site with a significant hill of perhaps 60 ft or more above a pond, it "might" be worth while to use wind to pump water up into a hilltop cistern. This would provide gravity feed water into the cabin, and on occasion, you could open a valve to downflow some of the water through a Pelton or Turgo thats right next to the pond.

One of the odd benefits of hydro is that if you have a significant amount of stored water at the head, you could throttle the flow to directly generate 110 or 220 VAC. And of course you could always charge a battery if desired.

Rocking horse pumps in oil fields can lift oil quite an elevation with an ocillating sucker pump (a check valve at the foot of the pipe, and a check valve built into the piston just above the foot).

Each wells depth varies, and if the counter weight on the other end of the rocker is well matched to the weight of the column of fluid being lifted, it doesn't take much energy to run it.

I worked at a landfill where wells were bored to draw out methane from decaying trash. it was burned to generate electricity for the city (~50% landfill gas, 50% municipal gas) The wells had moisture condense in them and clog the gas suction tubes, so sucker pumps were installed to keep the fluid low. Small copies of crude oil rocker pumps, but driven by air motors.

My job included occasionally replacing worn piston seals. Most wells were about 200 feet deep, so I know the idea would work. Of course with my luck, I'd dig a big pond, build this elaborate and complex system, and there wouldn't be enough wind to spin a VAWT, much less pump water.

Where I am now, I don't have a hill or a pond, and my grid electricity is cheap...

"Surely you must be kidding...

I'm not kidding, and stop calling me Shirley" -Airplane

[fcfcfc]

Hi:

Interesting thought but not really doable. If you think about it, that is the fundamental principal behind dams. You let nature do the lifting with sunshine (water vapor), it rains and flows down and fills the dam up with millions of pounds of water where the energy can be extracted with head pressure via a turbine and gen..

The cost of the mechanicals to support a "solid solution" would be reminiscent of the great pyramids... slave labor and such...LOL..

Keep thinking... Chemical storage could be a solution because a chemical process can yield a huge amount of energy in a small space...the trick is to find one that is reversible and can "loop" indefinitely.... such as melting salt to store heat then it gives up that same amount of heat on cooling, I.E. phase change.... etc...

.....Bill

[zap]

http://www.fieldlines.com/story/2005/11/10/191155/99

http://www.fieldlines.com/story/2007/4/14/63433/1343

[Jeff]

COOL! Add rain storage into the "engineering and collecting", keep it on the smaller scale you're maybe thinking of (maybe 55 gal. drums?), and use that to power a generator made-to-fit like the ones used on windmills that many make here. Use THAT to keep a battery array charged, and you most likely have something! Add a "demand" start and stop function when batteries are charged or need charging.

Another thing to consider may be adding a hydraulic water pump to increase efficiency. Adding a larger storage area maybe? A 12ft. "kiddie pool" bought at Walmart is about 3ft. deep, and holds about 2500 gallons if memory serves me correctly. Cost is about $120-$150, and comes with a pump & filter system. I bought the liner only once, and it was about $55. It could be put in a hole in the ground if you didn't have the plastic "outer part" to keep it above ground.

Also look here for some handy conversion programs, and places to look:

http://www.fieldlines.com/story/2008/8/9/164327/3794

I add this to my HOTLIST to keep track of!

Good Luck!

[dnix71]

http://www.msstate.edu/dept/geosciences/CT/TIG/WEBSITES/LOCAL/Summer2003/Daniels_Clarissa/raccoonmt.
htm

It's been done, but Raccoon Mountain has enough head to make it work.

http://www.physics.ohio-state.edu/~wilkins/energy/Resources/Lectures/storage-alts.html

[Dave B]

Just another example of pumped water storage and power generation, the Kinzua Dam not too far from me and a link here with some details. http://en.wikipedia.org/wiki/Seneca_Pumped_Storage_Generating_Station Dave B.

[bgarrett]

Hi Bill How did the earth tubes work out?

I want to install some this winter.

Thanks

[fcfcfc]

Hi:

I did not get them hooked up into the building this Summer. They are still waiting outside the wall... Just too much to do... I don't even have my final layer of insulation all done... still about 75% to do... there is just so much.. I still am playing catch up... but I am getting closer to sanity... I am trying to get my geo thermal heat pumps on line.. I have no backup heat right now in my house, and have been going along on solar hot air... its been fine so far but I believe my luck is running out this week to come....

Thanks for asking....

.....Bill

[brokengun]

What about air compression? It probably takes way more torque than a windmill could handle though... it would have to be geared quite ridiculously. It could be controlled really well though if it worked. Just have it compress a big tank all the time, when the pressure gets too much (and you're not using the power) have it kick in a dump load or onto the grid. It's a pretty clean way of storage, relatively compact too. I don't know how much you loose though going through the compressor and then out through a generator...

[Jeff]

Damn! Brokengun! Beat me to it! Was just thinking of this last night! Don't get greedy, and use a slow but very efficient pump to store the air pressure. Old propane tanks are cheap, but fill them with air or argon first & bleed the daylights out of them!