suggestions re: my site accessment

[boarder girl]

Hello,

I am reading the book Microhydro by Scott Davis. I have gathered information on my site which I think is a good canidate for a microhydro system. I would like to share what I know so far and see if any of ya'll have a suggestion as to what system would be best for my situation...I'm looking at having a battery charging system with a inverter for AC. Here's my site:  4 acre pond which is created from a diked up creek. Overflow from the pond falls down a large vertical tube 9 feet to a large horizontal tube which extends maybe 20 feet before emptying into a creek. The horizontal tube is 1 foot above the water level of the creek (max head of 10 feet?). The flow from the horizontal tube is 150 gpm (30 gal. container filled in about 12 sec.)

Question #1: Would this be considered a high flow, low head situation?

I think the simplest thing for me to do would be to design a half moon shaped plate with a pipe(penstock)inserted perpendicular to the plate at the lower quadrant of the diameter. I will then use this plate to seal off the lower half of the opening of the horizontal tube of the dike.  I figure I will not need all of the flow so this will allow the tube to backfill until it overflows the top of the plate.  At the same time water will enter my penstock where I will install a pressure gage, shut off valve and eventually a nozzle once I determine the best size per whatever system I should use. I see this penstock only being 2-3 feet long so I think I can neglect figuring for frictional losses. Besides I will have a pressure gage that will hopefully tell me what I need to know to help determine the appropriate system.

Question #2: Am I headed in the right direction? If so, what size pipe might I use for the penstock?

My goal would be to have enough power to run an airator for the pond and something to tap into in the event of a power outage for lights and possibly refrigeration.

Would appreciate any response.

Thanks,

Lori

[ghurd]

Choose the aerator carefully.  Some of them use just an extreme amount of power for what they really do.

It may be a good idea to build the pump also, using DC for power.

I like the 'bubble type' for low power consumption. A pipe from almost to the bottom to almost to the top, where the air is fed in to the middle somewhere.  Gravity circulates the water. The bubbles add some oxygen, but most gasses are  transfered at the surface naturally. The same way an air powered fish tank filter works. The air rises pushing water up (or the water with air in it is less dense- however you want to look at it), drawing water from the bottom to the surface where gas exchane happens. So the pipe is needed for it to work best.

There are 12v commercial air pumps available (DC8, DC15, DC20 and DC40 come to mind, google will help find them). Most data is related to only using the air it pumps for aereation. With the 'pipe', the air is used mostly for water circulation, so the 'aerated gallons' data will be somewhat insignificant.

The fountain type use tons of power and higher pressures. I read clogging can be an issue if the intake is near the bottom, and that is where it usually needs to be.

The paddle wheels use a lot of power too. And they stir up the water a lot (opinion). And they are ugly. And they are just so darn noisy.

OK. Nothing about the hydro system. I thought this stuff was important to know before choosing a water genny design.

G-

[finnsawyer]

I'd be concerned about partially blocking the outlet.  Presumably the overflow was designed with potential flooding issues taken into account.  If you partially block it you create a situation possibly causing water to overflow the dam sometime.  If you have a properly built spillway it might be ok.  I think you should condider an open design using something like a  floating paddle wheel in a sluice.  This allows the system to work even if a large flow is encountered and does not restrict the output.  In this case you rely on the speed or momentum of the discharge water and not the head.  There was a posting recently about two power plants in Germany using the two different setups on the same river.  You might check it out.

[boarder girl]

Thanks for the response.  That was actually my first idea (paddle wheel).  However, the book I'm reading doesn't cover that. But I will look into it because I think it may be simpler and more cost effective?  I'm probably going to "jerry rig" something in the beginning just to get it to work and then upgrade from there if it is feasible. Thanks again,

Lori

[ghurd]

A small AC induction motor conversion will get some power easy.

Factory windings should be good for low speed generation like a paddlewheel.

At least I think so.

It would just be switching some wire ends around and adding some magnets.

G-

[Off Grid Ale]

Dear Boarder Girl,

     Yes, it does sound like you are going in the right direction.  In my judgment, the high-flow will make up for the low (10') head.

     You know what, the real kicker is where you plan to get your equipment.  If you are going to use plans from Fieldlines, that is fine.  But do not discount the websites available from vendors who would like to sell you equipment at high-retail.  They often have calculators that can help you estimate what size wheel, generator, etc you will need.

     It might be also that you could find someone through this site who could take more detailed information--sketches, your power needs, your budget, your mechanical ability--and come up with a good design proposal for very cheap or just as a friendly gesture.  

     And well HEY!  If you need a nice battery, please consider my HUP Solar One listed in the Classifieds!

Austin Elliott   540-392-6554

     Sorrt to say, but the comment/response from "G-" seemed to be speaking to another problem entirely.

[ghurd]

I mean to say some of the suggested aereators for a pond that size use 20 HP motors.

There will not be enough generation from the site to power them.

Choosing a lower power comsumption aereator will be the only way to power it from what power is available.

Those aereator makers have no regaurd for power comsumption.

G-

[Aelric]

Just a thought, I don't know much about aerator's for ponds but the aquarium I had used just a simple stone that would diffuse the bubbles to help oxygenate the water for the fish.  If that is correct for this application as well then I was also wondering if something like the Air pressure watermill would work.  A couple months ago someone posted an article about using a windmill to pressurize air for pneumatic tools.  They just used a small engine (to pressurize the air) turned by the windmill and the exhaust from the engine (just air) hooked directly into an old propane tank, just would have to have some kind of pressure switch so you don't blow the tank up.  Anyway my thought was what about a system like that with a permanent magnet genny hooked up freespinning till you are ready to charge the batteries... or even better, use a normal air compressor as a dump load to aerate the pond?  Just a few idea's.

[geoffd]

Hi

Here is a simple calculator I've been using.  

http://www.energyalternatives.ca/content/Categories/MicroHydroInfo.asp

Worthwhile for a quick guesstimate.

Cheers

Geoff

[ghurd]

Most of the windmill aereators have a very low max pressure. Like 10 or 15 psi (?).

And they do not really do much for a pond bigger than 1 acre, so a 4 acre pond

would call for maybe around 4 to 6 windmills, depending greatly on who is asked.

Then there is the no wind situation.

And the low pressure means circulation from the bottom of the pond is minimum.

The air output is best maybe about 3 or 4 feet down.

And thoses things are not too cheap. They have some considerable hidden costs.

(like cement, labor, repair kits, freeze kits and fluid, extra hose / tubing, etc)

They do work quite well for de icing small ponds, from what I have seen.

All of that relates to the most common 2 or 3 brands.

G-

[boarder girl]

I think that is a great point about not obstucting the discharge tube. I am definately leaning toward the paddle wheel idea now. I have a squirrel cage blower I could use but I use it for a fan for my horse in the summer - I hate to destroy it.  I wonder if anyone can give specs for a water wheel design...number of paddles, angles etc.  I think I could machine one up or even make out of wood and paint it for that matter. Remember, I'm not looking for anything fancy at this point. Any ideas, anyone?

[boarder girl]

Where can I get instructions on how to make one from an induction motor?  Especially the part about changing the wiring around.

[Gary D]

On the link below, you could get an idea, or buy the plans for building one... A quick number crunch with your data (flow and head) gives a possibility of around 200 watts. If you click on the sample pages (waterwheel workbook), there's a lot of info. Interesting read at least.... Gary D.

http://www.waterwheelfactory.com/store.htm

[nothing to lose]

"Overflow from the pond falls down a large vertical tube 9 feet to a large horizontal tube which extends maybe 20 feet before emptying into a creek. The horizontal tube is 1 foot above the water level of the creek (max head of 10 feet?). The flow from the horizontal tube is 150 gpm (30 gal. container filled in about 12 sec.)"

Never messed with the hydro myself, seen a few, that's about it.

Anyway I was wondering, if you have a 9' drop, can you install a couple small gennies in that area. Water hits the first, drops to second, etc.. Seems you could get more power feeding from one to another that way. Perhaps use a paddle wheel/bucket type semi enclosed so that the falling water is trapped on the downhill side as it turns then dumps out the bottom into a funnel type base that feeds into the next wheel.

 I am thinking maybe you could fit 3 2' wheels in that 9' drop, wire them all to the same battery bank, get close to 3 times the watts?

[ghurd]

Right here is probably the only place, except for some users personal pages.

It is not as hard as it might look at first.

A couple pic's here,

http://www.fieldlines.com/story/2005/1/13/55530/4730

A couple searches will help.

I like hiker's 'Maytag'. Cheap and simple.

Jerry's Garbo-gen posts give some very nice information.

Zubbly's conversions are amazing. Some are a little intimadating to me, when he jumps in and changes all the wire! He did a great 3 part post that covers everything, there is a link. It is a huge file.

http://www.fieldlines.com/story/2004/8/14/114311/149

Part #2 is missing, I can't find it.

You might consider starting out with a TDM or treadmill motor.

Some are ready to use.

Have you read the Otherpower hydro section?

G-

[boarder girl]

So let me get this straight...you use the stator from whatever motor and make your own rotor?  Do you have to maintain a certain gap between the magnets and stator or do you just get it as close as possible without striking the two?  Very cool!  Thanks for the details.

[boarder girl]

Interesting thought!  But I better concentrate on getting one working first. I do appreciate all the creative ideas, though.

[boarder girl]

I'm wondering how you figured 200 watts.  The formula I have in my book is:

gpm x net head /10 = continuous watts  (net head being say 2/3 of the static head) so this is what I come up with:

2/3 x 10 = 6 (net head)    (150 x 6) /10 = 90 continuous watts.

Since I'm leaning toward a water wheel is there a formula that applies velocity of water instead of head?

[ghurd]

I am new at this...

But the closer the magnets are to the laminations the better the output.

Catch 22- Too close and the power it wants to make could be more than you have to spin it, so sometimes it is better to have them a bit farther appart.

And sometimes the magnets try to hold on to the laminations, making it hard to get started spinning. It is called cogging. Maybe that will not be much of a problem with hydro?  It can be with stop and go wind.

Picking a good motor to start with will help.

It is easier than I expected. I spent months reading, buying, planning...

Then, when it all came together, it was just reassigning the coils, cutting the rotor a little smaller and gluing on magnets.  I think I could do more in 2 to 4 hours each start to finish working time!  (Not including watching epoxy cure, etc)

All the reading sure helped avoid problems.

Everyone here helped when there was a problem!

Great people here.

G-

[Gary D]

Hi boarder girl, I just used the table on the waterwheel's page and plugged in your numbers- 10 foot drop and 150 gpm flow. You may be closer depending on alternator losses (total system losses) and such, however many waterwheels have shaft effienies of over 90% (his calculates are at 85%). If you build a paddle wheel (like spokes of a tire) the water will enter at the top, or 12 o'clock and fall out at 3 o'clock. If you put them slanting, the water will stay in your wheel till closer to 5 o'clock giving you a higher effeciency.

 The link I used for the 200 watts is below... maybe I punched the wrong numbers in. It's good to double check any of my numbers... The numbers on his calculations are in fractions of a horsepower (in your case and need converting into watts). As for several wheels or one big one, there is only so many watts available in x amount of water falling x feet. Drawbacks to both, depends on taste, one large or several small, same potential power...  Gary D.

  http://www.waterwheelfactory.com/HP20Table.htm

[Gary D]

Dang, forgot the % in the link, sorry. will try again.

http://www.waterwheelfactory.com/HP%20Table.htm

[rotornuts]

Boarbergirl, if you used an overshoot water wheel you can use the wieght of the water to tremendous advantage as you have lots of flow. Water wieghs about 11 pounds per gallon so if you had three or four 2-3 gallon buckets full of water at any time you would have 66 - 132 pounds of force working for you. It will rotate slow but with that kind of power you could gear you alternator.

[Nando]

Lori:

9. feet or 2.7 meter,150 GPM or 9.45-LITER/SEC, the power available is:
   
2. 7 * 9.45 * 6 = 153 watts, though due to the lower head you may expect around 100 watts, or 2.4 KWh daily
   
   

Other consideration, how is the creek from the pond to the exit of your land borders, the head in feet or meters ?.

If you have additional head there then additional power is available.

All the exiting water is usable to generate electricity. YOU NEED ALL THE FLOW

Your idea ( Item #1) needs careful investigation -- It looks like is not a good way to do, there are more practical systems, PHOTOS is best to see what is best for your site.

A small Banki or a propeller turbine may be the solution, using a 3 phase brushless motor capable of wide voltage generation ( no battery clamped ) to be able to automatically increase the power with the available and variable pond overflow levels -- a charge controller with input capability of about 3 to 5 times the battery voltage.

FORGET ABOUT Paddle wheels, useless in this case -- USELESS

The arrangement for item #2 needs more info, like photos

If you are serious about this project, let me know to assist you better, I do have Hydro experience.

Regards

Nando

[boarder girl]

Nando,

Here are pictures of the site.  It has been very dry here so this is the least amount of flow. I have tried to find an example of a Banki turbine. I have not found a good picture but it sounds like it is somewhat similar to the fan in a squirell cage blower.  Is this correct?  If so, I have one along with a generator (can send pictures if neccessary). I look forward to hearing what you think.

Thanks,

Lori

[ghurd]

Lori,

Any progress or ideas on how you will procede?

G-

[boarder girl]

Yes, just today I blocked off a portion of the discharge tube and created a flume/weir type thing with an adjustable gate (nozzle). I was just experimenting to get the right shape of a nap of water to enter my turbine. I have changes I want to make because I am uncomfortable with allowing the tube to fill up with so much water. The next design will not allow much to fill up, it will basically just provide the shape of the discharge I want (slightly narrower than the width of the turbine).  I will send pictures of prototype nozzle #1 in action. The bigger challenge will be how to mount the turbine.  I don't mind wading out into the water but it is a little cold right now! At this point I just want to turn the fan.  I'm hoping to do the more efficent thing - capturing the normal flow in a 4" pipe (equipped with emergency overflow capability, of course). I'm still in the initial stages. This project is not going to happen over night - my damn job keeps getting in the way!... I will try to keep you posted.  Thanks for asking - it gives me incentive to keep working!

L

[ghurd]

Returning to something from the first thread.

About blowing bubbles to pump water from the bottom to the surface,

so natural aereation can occure.

Low power needs.

A pic is worth a million words.

http://www.quantumlynx.com/water/back/vol2no2/v22_st5.html

THATS what I was talking about!

Your purpose (other than fun) is just to move the water around with low power made by the overflow, so you only need a discharge head of an inch.

For the question you are going to ask next-

No, I can't figure out how to run a fish tank bubble maker from 12v DC. Not with any efficiency at least.

The question after that-

Those little battery pumps, like from the pet store or sporting good shops, only last about 100 hours and the plastic cams wear out.

Even the expensive ones.

Just in case-

Windshield washer pumps only run a minute or so pumping air (burn up with no cooling I think)

And they burn up pumping water continiously in just a few minutes too.

Hope my many years of very extensive experiance in the broad field of burning up perfectly good brand new expensive things saves you some time, money, and frustration!!!

(that means I know more about what won't work, than what will)

G-

[boarder girl]

The air compressor should not be a problem for me as I used to design them at my former job. Once I know the amount of power I can generate I will get in touch with my buddies at Gast and get just the right one for the application.  I'm thinking a rotary compressor.  The lab throws out perfectly good ones all the time (used in tests etc.). I know you need pressure in order to go very deep.  Told ya, I have access to lots of stuff!  Now if I just had the time to pull it all off!

: )

[ghurd]

"lab throws out..."

Ahhhh!!!

(sorry- that happens sometimes)

And its about 2.4PSI per foot down, but you knew that.

Read somewhere, the smaller the bubbles the better it works. They rise slower and that gets more air in the same water volume.

Could a Gast air motor be setup to run on water?

Maybe that would solve the turbine problem?

Doubt it, but it jumped into my head.

Gast?

Will the LOA or ROA (DC) handle 120PSI?

The chart says 100PSI max, but I figure there is considerable safty margin in the publications.

I'm looking for a smaller 120PSI air compressor that can be run from a 1/4HP 12VDC motor for a dump load. Has to be long life (oiled?). Can't find one.

I think Thomas made one for soda dispensing machines, no longer listed.

G-

[boarder girl]

An airmotor can be used with water but it will ruin it.  I hate to admit it but my husband once coupled two air motors together and used one to pump water.  My engineer buddies at Gast cringed when I told them that - but it did work.  I don't know how long the vanes would last - not designed for water.

Your best bet concerning 120psi question would be to contact Gast.  They would be happy to give you some direction.