Why Has No One Thought of This or Where do I Purchase . . .

I don't know of any "bi-directional" pump generators, but I have set up small, off-grid systems like this. Hybrid systems with micro-hydro and solar the diversion load (triggered after batteries are charged) first starts a pump and runs it up to the storage tank for the hydro. There is a lot of loss in efficiency in system like this, but is better than uselessly heating air. The power needed to pump the water is going to far exceed the power produced by the hydro. And, unless you are running a hydro big enough for regulated AC (3kVA+) or a pure DC system, you need the batteries to ballast the voltage from the micro-hydro generator.

BTW (head(in ft) X GPM) / 10 = output in watts for a standard micro-hydro unit. So (10 (ft) X 100 GPM)/10= 100 watts. And with 1000 gallons this will last 10 minutes. 100 ft x 100 GPM = 1kVA which is about what an average US house needs. 100 GPM X 60 min X 24 hours = 144000 gallons per day.

Conceptually ,the Tesla Turbine is such a dual purpose beast, although lacks the professional validation to actually have a source where you can purchase one. Most are hand built by enthusiasts.

As has been pointed out, this is technically called Pumped Storage. There is a dam facility on the eastern shore of lake michigan.

Why do you want the pump and turbine to be the same unit?

Chris

Awesome!

My numbers indicate only 0.3 to 0.4 [kW-hr] for 1000 gallons at 100 ft head. This is an order of magnitude lower than your estimate. Can you please double check your calculation?

Yep, 0.314 kWh (based on US gal)

Codey

Potential Energy = mgh, so roughly 4545kg * 30.5m * 9.8 = 1.36Mj

And since J/sec = W 1.36Mj/3600s = 377 W for 1 hour

Multiply that figure * something to account for efficiency and losses and it's not much at all.

Only 1000 Gal.? you would need to restrain the flow so much, in order to keep the watter flowing for hours, that you would have a tiny little squirt trying to turn a generator, if you wanted more torque, you'd need to increase the height of the water fall, and thus consumming more energy to pump the water up there.

If you really want to run it off the grid, you'll need to collect mechanical energy from your environment or invest your own (i.e. peddling a pump etc.)

No matter what you do, you'll never get more energy from anything, than the energy you spent. In fact you will not recover even the ammount of energy that you invested.

It's a good project to see how things work, but you can't benefit from it, instead you'll despair and destroy the apparatus on a rage.

Keep investigating

Yahlasit

If you read the OP carefully, he's not trying to get something for nothing - just investigating it, as he states, as a form of "battery".

He just needed to do a few back-of-envelope sums before bothering to go through the search for the pump/motor/genny combo.

Neither am I saying he's trying to, but if YOU read his post carefully, you'll see he wants it to run off the grid, but at the same time he mentions: "...motor-generator..." and "...when power is applied, water would be pumped..."

But don't bother to reply me, better try and help him, but first, carefully read posts from others, they're enlightening.

Yahlasit

And I quote directly from the OP, "I am estimating a system size of 1,000 gallons for a proof of concept installation."

Now, a quote from JohnDG, "If you read the OP carefully".

Now a quote from me, "Read the OP again, carefully!" and do not add your own interpretation of the words!

In closing, another quote from you,"but first, carefully read posts from others, they're enlightening."

3 good answers already, but here is a little perspective. I am always thinking of ways to cut power consumption and am partial to energy recovery. Some time ago I looked into collecting energy from several sources and storing it with a clockwork device.

I wanted to use wind, wave, tidal, river, truck or whatever power I could harness to lift a heavy weight (stone or scrap metal) that would power either a clockwork generator or a gear driven machine to reduce electric consumption.

I discovered this website that shows how much some common appliances use and how to compute others. I quickly discovered that either I needed more weight or more height and a much better supply of free energy to power much more than a garage door opener.

I finally settled on using my truck to lift a weight every time I enter the garage that will store energy to operate my garage door opener...now all I need is to finish college and get a garage to install the opener on!

I will look for other uses applications where I can recover and utilize energy lost through waste.

Drew

Something just struck me.

Does your design use a "clockwork generator or a gear driven machine to" to raise the garage door? Is it electromechanical or mechanical-mechanical?

And do you recover some of the energy when the door closes? I guess you wouldn't use much anyway.

Not sure...haven't built it yet. The door would probably be neutral balanced with a counterweight so it takes less energy to move it. I thought if the vehicle drove onto a short ramp it would raise a weight that would be capable of several open / close cycles before requiring another 'charge'. I also thought this would be good for farm gates too far away from an electric source.

I originally got the idea when I was in the Air Force stationed overseas and we had to open and close the gates to our fuel system every time we drove the trucks in and out to fill them. I thought of installing a rolling gate that would be powered by driving the truck onto a short ramp that lowered quickly and either raised a weight that controlled the gate with gears or charged a hydrolic accumulator. I think for a home garage the weight would work best, might take some safety controls to ensure no kitties (Del) or anything else could be caught in the mechanism.

Drew

Good idea - but you'd have to judge your driving very finely to get real "free energy". You'd have to get your approach speed just right so you didn't need to accelerate to get up the ramp and didn't need to brake to stop going too far (I think! ). Effectively you'd be capturing the energy which would otherwise be lost heating your brakes.

I guess your starting point is to take the speed you'd normally be driving at when going into the garage - say 2 mph(?) - and see what gradient is needed to stop the truck in the length of the ramp.

(Shut me up - I'm rambling!)

I thought about something similar, but on a much larger scale. Certain areas of the planet get lots of rain in the mountains. My thought was to collect the rainwater on top of the mountain in a receptacle about the size of a railroad car. Two of these would be on a looped track running to the bottom of the mountain and attached via chain and sprocket to a generator at the base. These receptacles would be on opposite ends of the loop and would both create electricity and deliver fresh water to the village below. Once the receptacle at the top of the mountain is full, it would release, creating power and pulling up the empty vessel from below. Once in place, it seems as long as it rains in the mountains, this system would work indefinitely.

Now that is very interesting.

There would be way too much mechanical loss, but the same idea could be applied to an electro-mechanical system. Drive each car with a motor/generator so, when gravity driven, electricity is generated. When at rest, applied electrical power causes the motor to run. The empty car is much lighter than the loaded car, so with decently efficient motors, the concept is very workable with some energy even left over to store for other uses such as lighting, signals, controls, etc. Of course the electrical connection from one car to the other is through the tracks and a third rail.

The trick in this application as with any other similar endeavor is to capture expended energy (such as braking) that would otherwise be lost. Or never used in the first place as with the garage door opener or gate opener.

The op's concept with the 1000 gallons of water 100 feet or so up in the air does not work because he is trying to use energy that is already in the system and that is not being generated by some internal process for which it (the energy) would not otherwise be used.

Oops. I have rambled enough already.

I like the idea of a big heavy flywheel better. Use surplus power to pump energy into it for later recovery via a motor/generator.

Since you are claiming off-grid use, the pump power must originally come from solar cells and/or wind turbines. The intermittent nature of these sources requires the controlled storage and distribution of the gathered energy. Pump storage hydro does work well on a large scale and in specific geographic locations.

Cost and size are impractical for small scale (e.g. single home) applications. You would need storage capacity on the order of 1/4 to 1/2 million gallons of water at a 10 meter height to meet the daily electrical energy needs of even a small home.

If you hunt around you can find small water turbines. However, their efficiency is around 70%. Small pumps have similar efficiencies. So you lose more than half your energy in these inefficiencies for a start.

Even if you have a piece of land with reasonable fall, as I do, the cost of tanks big enough for a system like this is greater than the cost of lead acid batteries.

As you say, the batteries CONTAIN toxic materials. So it is contained. So where is the problem?

This forum is intended to aggravate the thinkers into a defensive position and the natural response is to share their thoughts in an effort to satisfy their egos. OK I'll bite. A water battery is not great for an off grid generator. It can reduce the peak demand on a grid system and result in a small reduction in your bill. Maintenance and repair of the system will most likely offset the savings at that scale. Nothing is free. I will keep thinking and one day will succeed. Gary

After reading posts # 18 and 19, I'm speechless, and gone.

I am speechless too... but still capable of writing.

It is stunning to see an OP who cannot recognize the helpfulness of responses that have indicated that the concept of pumped storage is not workable on the infinitesimal scale involved. My inclination would be to write something vaguely insulting, but I realize that the OP would not "get it." Instead, I would encourage the OP to do the structural modifications to his home, to get the variances required and fight the legal battles to do so, suffer the loss in value of his home, spend the money for all the system components, do the plumbing/wiring/construction, and endure the ridicule of his neighbors... all to run a system at an economic net loss. One can only hope that, by engaging in all this, he is at least not spending time procreating.

It's as if he asks: "I have this great idea to burn the wood framing in my house to heat it. What's the best way to start the fire?" Then he gets ticked off if we suggest a rethink. I guess the expectation is that we should say "Great idea! Try matches."

I guess the Original Poster cannot handle the dose of reality served. Perhaps this is another incarnation of WWL and will begin measuring gasoline at a gas station with a plastic petrol can.

Several members provide detailed math showing the return on the O.P.'s proposed Idea, another gives an example on what can realistically be used in a similar fashion and the O.P. has the audacity to lash out with his / her vitriolic comment.

Larry.19 If you do not like our comments or company you are welcome to find another forum to participate in.

My opinion is that Ego had nothing to do with this thread until now.

Anon

You see son ? I was trying to save you that !

At least I'm honest when I have to disagree, but I'll never be so ungrateful that I'll jump to your rear end while you're picking up my glasses.

Yahlasit

And please note that I'm not asking you to remain speechless if you ever come back !

Yahlasit

In fact, I would like you to come back; just pretend this never happened, make no comments about it, and I promisse I'll never mention the episode.

Yahlasit

Hi Larry.19,

These NZ guys have developed an innovative hydro generator using the drive motor from F&P washing machines as a generator.

http://www.ecoinnovation.co.nz/c-6-hydro.aspx

You can also obtain the wheel buckets and other components for your own DIY. There is some basic hydro info which may be handy and some other solar/wind combinations.

This refers to a major problem facing solar and wind - storage to allow time shifting to periods where the electricity can actually be used. Some of the best minds in industry are working on a solution - actually many potential solutions. The problem with gravity solutions is the immense amount of weight to be moved to make meaningful power - even to power one home. Forget home hydro storage.

I have learned that there is not enough land area to install wind and solar generation, not to mention NIMBY (Not In My Back Yard), even with energy storage.

Better, in my opinion, to go with nuclear. It can do the gigawatt amounts that society wants in relatively small space. The new technology designs (IFR, thorium, etc) have eliminated a lot of the problems with the reactors we are used to thinking about.

There is more than adequate land - that is not the problem. Having said that İ also would love to see nuclear being built in quantity.

Bit off topic but.. We had a property one time, connected to a very high
pressure district mains water supply. The direct pressure was way above 100psi
and high value reducing values were needed to provide each normal supply.

The inclination was... to install a small pelton wheel - and let it spin!
Free (stolen) electricity for ever! With all the leaks the water board claim today,
it would probably have never been noticed. (although they do check some times)

Conscience got the better of me. Just an idea for the op. (any nearby water mains?)

jt.

The man who tells the truth is always at ease.

You are from NY, but it doesn't say where. If it is upstate and western NY,take a drive down US 219 through Bradford to Pa Rt 59. Turn right. When you cross the big bridge over the Kinzua reservoir, turn left immediately after crossing. Take first right on paved road. Paved road forms a big loop in about 1.5 miles. Off the backside, take the dirt road for about 3 miles to road to right. At end of this road see the huge asphalt swimming pool. In reality, this is impoundment for water pumped up from the dam at night, and flowed out through generators below the dam in the daytime. Gravity battery, and it is AC. Been there since at least 1980, when I first discovered it.

This is probably the one - looks pretty

Seneca
Location: PA
Operator: FirstEnergy Corp
Configuration: 2 X 210 MW FPT, 1 X 30 MW Francis
Operation: 1969
T/G supplier: NN, BLH, WH
EPC: Harza
Quick facts: Seneca power station is co-located with the Corps of Engineers Kinzua Dam (179ft high) and Allegheny Reservoir in the Allegheny National forest. The plant has a 102ac site and was built as a joint venture of Pennsylvania Electric Co, then a subsidiary of General Public Utilities, and Cleveland Electric Illuminating Co, later merged into FirstEnergy Corp. In 1999, FirstEnergy bought out GPU's 20% stake for $43mn. The upper reservoir is on a sandstone plateau about 800ft above the river and formed by a circular ring dike about 1/2mi in diameter and ranging from 30-120ft in height. The original Woodard governors and unit controls were changed out during spring outages in 2006 and 2007. The new equipment was supplied by L&S electric and Allen Bradley.

Half way around the world and then down three quarters of the way to find a picture of it. Yes - that is indeed the installation I refered to.

Yup - took me a while to track it down on Google Earth. Couldn't get my bearings - ended up following I-80 for about 50 miles til it met US 219 & so on...

Here's the Wiki link.

There are numerous pumped storage units in service in the US, Canada & Europe.

Mine is bigger;

Guangzhou Pumped Storage Stage II Project

It's a PDF (but can use 'quick view') go to about page 15

It makes it all clear what the extra bits the OP needs to make it viable.

Exerpt for the lazy; C. Attainment of Benefits

26. The objective of improving the safety and supply quality of GPHC and Hong Kong China Light and Power (HKCLP) systems has been achieved. In addition, the Project helps to improve and enhance the safe and stable operation of the Daya Bay nuclear power plant. With the Project in operation, the Daya Bay nuclear power plant was able to increase its base load factor steadily from 66 percent in 1994 to 85 percent in 2000. As a result, its annual power generation for the past seven years exceeded its nominal designed capacity of 10,000 GWh, without compromising its safety, by a big margin of 2,021 GWh, as shown in Appendix 13.

27. Every power system must have a reasonable margin of operating reserve to ensure safety and steady operation. The pumped storage plant, with its flexibility and ability to respond quickly, has been a reliable reserve, particularly with its spinning reserve. Its reliability was proved during the sudden tripping of the nuclear power plant unit 1 in the early morning of 24 February 1996, the Chinese Spring Festival, resulting in a power deficiency of 851 MW. While one pumped storage unit was pumping at full throttle, the pumping unit automatically changed into generating mode. At the same time, two other pumped storage units were brought into full-
load generation. All this happened within a time span of 3 minutes and 33 seconds. The quick response not only prevented system-wide failure but also ensured steady power supply.
Statistics showed that the Guangdong and HKCLP grids were hit by 99 system faults between 1995 and 1999, caused either by unexpected tripping of a large-capacity base-load generator or by sudden disconnection of power from other networks. The pumped storage plant came to the rescue on each occasion.

28. Peak-load shaving is the most critical service that the project's facilities provide to its connected system networks. Statistics taken between 13 and 19 August 2000 indicated that the peak-shaving capacity from the project facilities alone accounted for about 50 percent of all the peak-shaving capacity of the Guangdong system, as shown in Appendix 14. In the past HKPSDC had to rely on its costly gas turbines for its peak-shaving service. Now, HKPSDC depends heavily on the project facilities to perform this service, resulting in net savings of over HK$100 million.

29. In addition, the project facilities serve as an ideal tool for system frequency regulation. Its ability to carry out synchronous condenser operation is well recognized, since this type of operation can be achieved either in generating or pumping mode, depending on system circumstances and requirements, without relying on more expensive synchronous condensers.

thats what we like to see.. real installations - real data. What is the wattage of the panels? What are you using for an inverter? Are there any batteries in the system? How many amps are produced? What is your local average solar watts per square foot? (from the sun)

GA

Chris

Hi Morrie,

Around Margaret River I guess. Nice area.

Ok, as Chris has observed - now we know what you are about, time to be serious.

Some time ago, I experimented with something similar on my property between two tanks of 12 feet diameter x 6 feet high. The vertical elevation was 20 meters (200 kPa measured head, top tank empty) and I used 2" poly pipe to try and eliminate line loss, given, though the flows were tiny, but the run was 60 metres.

My best recovery was 21%. This was mostly due to the relative inefficiency of the small pump ~40% and tiny Pelton wheel ~55%.

The trick in hydro re-pumping is huge pipes and near vertical fall. Line loss kills them.

To get meaningful power you need big elevation (or big flow, but high velocity converters are more efficient).

To get efficient conversion you need larger scale pumps and turbines - excellently engineered.

As one does, I pondered doing this at 'useful power' scale. Using the main bottom dam (7.5 mega litres) and making a pond at near the the top of around 1.5 Ml - gave 200 meters of head and 350 line length, 24/7/365, drought resistant, to demand, power.

Then I did the bill of materials and costing.

You can buy a lot of panels and batteries for (in A$) quarter of a million.

One really needs to be of a scale to sell power, or fill grid demand gaps, to justify the capital investment. But get to that scale, with photovoltaic addition, you can eliminate 95% of power generation fossil.

I.e it's an interest that for me turned into a mission.

Given how that mission has been received over the last 20 years, outside Asia, where "greens" think dams are "crimes against ecology", and "friendly" is to plug their cars into coal fired power - my advice; treat it as a hobby.

Hi 34point5

Yes, I am not far from Margaret River and yes, it is a great area.

Before I installed my PV system, I looked at all sorts of alternatives, including pumped storage. I found a supplier of suitable turbines after much searching and obtained efficiency curves and did calculations and thought about putting in another dam up at the top of the block.

But when it all came down to it, lead acid batteries were the most cost effective answer. I have $9000 worth of them in my system. The fact that they are the most cost effective solution is the reason why there are thousands of installations across the country that use them.

It is natural enough to explore options. I did. Things like the Vanadium redox batteries keep getting mentioned on forums, but the reality is that they are simply not in the market place for domestic systems. Same thing with fuel cells. I'm sure you know about such things.

The battery system is actually quite inefficient in summer. When the batteries are full, they don't charge so even though the panels have lots of capacity, it is largely wasted. I should probably install a small air conditioner or something to use up the power. A grid connect system is much more efficient than a stand alone, as the grid is in effect a huge battery.

You could go for a grid connection and the two way meter. Thing is you also run into the red tape, and at the end of things they pay you about half of the kW rate.

A big freezer during summer is handy.

At the end of the day - it's the excess summer power that's bothering you - the panels don't care.

I use mine to fill the top tank then supplement solar heated water, as the winter heat is via a wet-back stove fed off the natural attrition in a few hundred acres of forest. The wind turbine also does better in winter, but must always have a load, so it is actually first to put water up or heat it if things are full.

If you'd like hours of fun - buy a wind turbine.

By the way, if that small panel is in series with the large one - the larger one's current may kill it. What I have tended to do, is use odds and ends like that, as maintenance battery chargers on the machines (tractor, dozer and whatnot).

But hey - don't stop playing just because you can't get the efficiency of a large scale system - it's free input - meaning 'efficiency' doesn't actually matter.

Any level of output or gain is far more efficient than buying energy.

Hey, it sounds like we are in similar situations :-)

I don't have the grid here and some real issues with getting a line put in so its not an option.

A big freezer might be worth considering I suppose.

The pump installation was purchased as is from a supplier. They sell lots of them so I assume that they have the electrical side of things worked out. Installing that pole and putting the panels up there on my own was a challenge! It wasn't cheap either, $10k.

If you look at the second photograph, you might see the size of the trees around here. A windmill is out of the question. I can't even fly a kite here in a strong wind. And that is the rule of thumb guide as I understand it.

Last year I installed an instant gas water heater to replace the wet back stove. I am getting too old to cut the small wood and it is not pleasant having a stove running when it is 35 degrees centrigrade! It has made a big change to things.

I'll keep an eye out for your posts.

Cheers,

Morrie

Chris-

I just installed a solar pool pump for a client. I don't have the technical details with me (I am out in the jungle again- I'll try and post some details when I get back to civilization). 3 each 4 foot by 6 foot 24 volt panels (series-connected) driving the centrifugal pump (I suspect on the order of 1 hp, based on the peak flow we get) through an inverter providing 48 V AC. no batteries. One can see the pump slow down when a cloud passes over the direct sun, but the inverter has a low-voltage cutoff to prevent over-heating the pump. In the case of the pool pump, 24-hour operation is not critical, and in the case of just pumping up to a high reservoir, one would not necessarily need 24 hour operation either. The helical pump, being positive displacement, might be a better choice for lifting significant distances...

Appart from all the answers which are good.... you cannot hope for a better efficiency than 50%. You will recover a maximum of <50% of the energy consumed to pump the water up. This is theoretical.

This method is already used on large scale whne there is excess energy available from the grid at low load time (to keep the generating plant running efficiently on low demand...) or when there is a free energy from TIDES (when the location permits). Water is then pumped to higher level and then used when the demand increases... Old story and not applicable domestically or at least not practical.

You could take the spare power and use the generator of a windmill as a motor to drive it like propeller. You could start your own personal jet stream around the world and harvest it for even more juice when you need it.

Nice idea. Don't forget the 4 tons of water in the attic.

QL

Hi all,

Just a thought. What if the op raised up only the 1000 gls (limited quantity)
and released it, at say 2gls/min. to give approx 8hrs of (minimal) generation.

However; consider his reservoir (loft/outside tank, whatever) was full, what
if the container was then substantially pressurised to increase the force of
the water expelled? (e.g by windmill, off peak supply, etc.)

What could be his best electricity generation result?

jt

Engineer - a person who gets it (me) to work. (my wife)

The power needed to pump the water up to the attic will exceed the amount of power you will generate. 1kw in = <1kw out; a net loss of power. Your attic floor better be able to withstand all that weight.

Review here before you attempt your proof-of-principle experiment:

http://homepage.ntlworld.com/regina.dengler/main%20content/full/about/i5.htm

Pumps as turbines will be the cheapest off-the-shelf way to test your idea. Also consider using dedicated separate motor/pump and turbine/alternator. Each can be optimized for a particular application. Added cost may be offset by improved performance. I still think small scale cost will be too high for all but a few isolated applications, but it should be a good learning experience for you.

It would be a device that when power is applied, water would be pumped from one location to a higher location (example: basement tank to attic tank) and when power is demanded a back-flow valve would open and the water in the higher tank would flow through the impeller, back down to the basement tank, producing power output from the motor-generator.

The way I read this post is: you have to buy power to pump water up. This is where I'm confused. You are using and paying for power, not using excess power as from a public utility. Generation of power takes place when the water flows down to the basement. This is gravity at work, but you have to buy power to get the water up to the attic.

Although the OPs solution has been shown not to be a good one, the problem he is trying to solve is a real, and, important one: that of trying to store energy from intermittent and unreliable sources such as solar and wind.

Also, the OP proposes to use solar power to pump to the upper reservoir, so this would not be purchased power. Even at say 60% total cycle efficiency, from an energy standpoint this is conceptually sound. The problem is that it takes a large reservoir to store much energy, so it is not financially sound unless various conditions are really, really favorable.