small river turbine generator

[goingoffgrid]

Looking to install small dc generator to compliment my soon to be installed solar system. I have a river abutting my property, and would like to utilize the fast flowing current. Wondering if I used a 12" PVC pipe and downsized it to an 8" and so on to create more velocity, and place the generator at the end. Will this work? I would like to have something below water so its discrete. Here's some pics. Any suggestions would be great. Thanks in advance.

[nick1234]

how about tiring the opposite feed the smaller pipe to the larger to create a venturi effect  you will move a greater volume of water = greater power   take care not to create a vortex at the venturi entry 
nick

[jlt]

A 6" turbine would not make much power unless you have a lot of head. your pictures are to small to show any detail of flow ,width,depth. Jackrabbit marine makes a underwater turbine that might give you some ideas. I think it has 12" blades.

[hydrosun]

If you are trying to be discrete you may want to forget the pipe. What you are trying to do is to restrict the flow to direct it toward the turbine. Putting large natural looking rocks would accomplish the same effect.  The more water you can direct onto the turbine the more power you can get. The formula is still gallons per minute times drop in feet divided by 10 for the watts out. It looks like you have about a foot of drop, so you'd get about 10 watts for every 100 gallons.  Most designs have the turbine shaft coming out of the water to a generator. I've read about people using a  boat anchored with a shaft going under the water to the propellor.   Other wise you need a waterproof generator like the one from Jackrabbit marine.
Chris

[12AX7]

Hello..

I'd suggest a few larger pictures to show more details.

If you haven't already seen it, I'd suggest you check out the waterwheel project that was located at on the otherpower front page.

Your picture,  does it show "normal" water level?  does it flood?  freeze?  From the small pics it's card to tell, but doesn't look deep enough for the jackrabbit.

A floating waterwheel might be the best choice.

ax7

[goingoffgrid]

Thanks for all your inputs, greatly appreciated. I will investigate the "jackrabbit marine generator". The water level is the lowest Ive ever seen it, it is typically 4 feet higher this time of year (spring runoff and spring showers). Driest spring in over 100 years. Sorry about the pics, I'm not too computer savvy. I'll try again. The depth is about 18" deep where the current looks strongest between the large rock and solid rock on the shore.The width is about 3 feet, but widens quickly as it rises. Normal summer levels in this location are 3 feet. A good part of the river bed is solid rock. I will also use the move some rocks around suggestion to create more velocity. The current at this time is strong enough to pull me in. Not sure how to measure it yet. Will continue to read this site.The river does freeze during really cold winters but not for long, and i believe always runs under the thin layer of ice. As far as being discrete, my property abuts a bridge and people sometimes stop to look at the river. (Out of site out of mind sort of thing). Thanks for your quick responses guys.

[greenkarson]

I have a similar situation. I went with a aquair made by ampair its a 100 watts.  Very rugged design 12" propeller starts charging at 6mph. really easy to set up I will post a few pics of my set up. Mine is mounted in a galvanized covert not ideal because of the ripple effect but works well anyways.  Mine is in a small dam so i can catch more of the water when the flow gets very low.  But looks like you problem have more water to work with.

[TomW]

So thats what happened to my trolling motor

Tom

[hydrosun]

I'm glad to see that you got the hydro working. Why did you put the turbine in the culvert instead of mounting it directly to the outlet of the dam? A smooth transition from  a larger opening to an outlet that matches the diameter of the propeller might give you a slightly higher output. Using some metal flashing to make a large funnel might work. Just an idea not a criticism. I like to tweek things to maximize the output.
Chris

[goingoffgrid]

That's pretty much what I was looking for. I'll look into the Aquair generator as well. FYI looked into jack rabbit, apparently went belly up. Every kw will help. Still working on more quality pics. Thanks for yours. Where did you pick up your Aquair? Yours is part of a larger system? Originally my thought was based on the old strip mining concept, they started with larger pipes and gradually went to smaller to create lots of pressure. I realise they also had head, but I thought the natural current through the pipes would create even more velocity.

[greenkarson]

found several "dealers" online only to find out after contacting them that most of them had never actually seen the unit and knew very little about it.  They are actually made in the  UK. The only company that knew their stuff was ABS Alaskan. But the shipping was going to kill me to get it from Alaska to Ontario. so just by luck i found a guy on kijiji.com with one forsale an hour from my place.  He had bought it then realized it wasn't right for his situation so i got it still in the box for 900$ compared to 1399$ on line.

I know the covert setup was not the best but it was solid and seems to work pretty good.  Ideally id like to find a piece of a big plastic sewer pipe just slightly bigger then the prop and mount it inside the covert as well.  Right now there is almost 2 inches clearance all the way around the prop. So i waist allot of water flow. but on the other hand i have seen water over 2 feet above the top of the dam.  That was another reason why i went with the covert with the bars in the front was to protect the turbine from logs and big debree that can come down stream pretty quick in the spring time.

 thanks karson

[goingoffgrid]

Hey Karson,
Did some on line research and found the Alaskan website. You got a good deal, and an hour away. NICE!! So your in Ontario too. I'm in Muskoka. On kijiji all the time, and getting into alternative power. Almost too weird!! I thought about the smooth bore culvert and pinning it to the bedrock. got a rock drill but will need at least a 2 ft bit. Saw the bars for the debris, good idea too. I also figure if the waters running in the winter under the ice it might give it some extra protection. I know they are rated for a max 100 w/h so what do you think it is really generating, and how far to your battery bank, what about line loss? I would be about 250 feet from river to batteries. Trying to determine if cost per kw is worth it. Do you know the life expectancy is of these units.
Thanks
Joe

[greenkarson]

believe it or not the guy who i bought mine from had 2 for sale i will contact him to see if he still has the other. With the proper wire to allow for losses 250 feet would be no prob.  I'm at about 150 myself. the turbines are 24v so that helps with wire run as well. They do come in 12v as well.  they are very robust no plastic all steal and aluminum  mine has been spinning now non stop for over a year.

[goingoffgrid]

That would be great. Let me know if it is still available.
Thanks

[Ungrounded Lightning Rod]

Originally my thought was based on the old strip mining concept, they started with larger pipes and gradually went to smaller to create lots of pressure.

That's one of the ways that fluid dynamics is counter-intuitive.  Narrowing the pipeline raises the flow rate, which LOWERS the pressure.  It's called "The Venturi Principle".

[TomW]

That's one of the ways that fluid dynamics is counter-intuitive.  Narrowing the pipeline raises the flow rate, which LOWERS the pressure.  It's called "The Venturi Principle".

ULR;

I find it easier to understand water pressure from gravity flow visually by thinking in terms of a water column the size of the outlet opening. not a whole lot of water weight in a 1/4" column 20 feet tall compared to a column of 4" at the same height.

May not be purely accurate but covers the in a nutshell explanation well enough for me.

Just a little aid to understanding that I use.

Could be purely wrong but just how I think of it.

Never had a hydro setup but have had several residences with gravity feed water systems and from experience know that I got no more pressure or flow when I upgraded one line from a tank to the house from 1" to 4" over a 100 foot run. The faucets seemed to dictate the end pressure more than the feed pipe. Same reason it doesn't matter if your tank has 10,000 gallons in it or 10, pressure from X height will be Y so we are back to that water column the size of the outlet bit. If that makes sense?

Just tossing that out there.

Tom

[greenkarson]

lets see if i can make it more  confusing.   height is the determining factor in water column pressure. Diameter is irrelevant to the actual pressure at the bottom of column.  If you had

a water column 10' high and .25" dia the pressure would be the same as if you had a column 10' high and 20" dia.  All the extra diameter allows you to have is more flow at the same

pressure.   A rough example in a gravity feed water system would be if you had a feed pipe .5" dia and 100' long with enough height to give you 20 psi at your faucet but if you were

to upgrade the feed pipe to 1" you would still have 20 psi but you would have enough flow to run two faucets at 20 psi instead of the one.
 
If you weren't confused before you should be now.

karson

[SparWeb]

Obviously neither of you are engineers.

Between the two of you, you still haven't made it as confusing as it really is yet! 

Always bear in mind that static pressure can only be measured when the water is not flowing.  This is usually the highest system pressure in gravity-fed systems.  As soon as the fluid can flow, the pressure you measure will drop.  Slight drop for restricted flow rates, more for free flow.  Where you measure the pressure also matters, because the pressure measurement at the nozzle will not be the same a measurement taken a few feet up the penstock pipe.

Rough pipe walls cause pressure drop when the water flows, exactly like wire resistance causes voltage drop when current flows.  In fact the analogy between fluid flow and electric flow is so good that you can use a lot of tricks to keep your facts straight, if you know one subject but not much of the other.

Doubling the diameter of a pipe provides 4x the area to flow through for the same pressure drop, just like doubleing the diameter of a wire allows 4x more electric current for the same heat build-up.

 

[hydrosun]

I had originally asked about the culvert and suggested using a cone shaped piece of metal to direct the  water at the turbine.  The cone would restrict the flow with low pressure loss. It slightly speeds up the water to let the same gpm flow through a smaller opening.   The amount of water that starts through the nozzle is dependent on the pressure. The turbine produces more power if you can direct more water through it.
 On a water system the amount of water that comes out of a faucet is dependent on the static pressure minus the pressure losses from the pipe and all fittings. If you change from a 1 inch to a 4 inch pipe you reduce the pressure losses in that section but if the losses are much greater in the house pipes  or plugged screens you won't notice the difference. Or if the pressure drop was minimum to begin with.
Chris

[Ungrounded Lightning Rod]

The cone would restrict the flow with low pressure loss. It slightly speeds up the water to let the same gpm flow through a smaller opening.

Note that the speeding up of the flow does not occur (directly) because of the narrowing of the cone.  It occurs because restricting the opening reduces the total flow in the pipe by reducing the area through which water can leave.  This lower flow reduces the pressure drop from friction in the pipe bringing the water to the nozzle.

The conical approach to the opening is just to avoid additional pressure drop by losing kinetic energy when flowing water has to make a sudden irregular turn and ends up flowing turbulently.

[hydrosun]

I agree that the cone doesn't cause the water to speed up. But it does speed up at that point. What is a good way to express the reason it does that?  The pressure differential forces the water to speed up through the restriction  ??
Chris

[Ungrounded Lightning Rod]

I agree that the cone doesn't cause the water to speed up. But it does speed up at that point. What is a good way to express the reason it does that?  The pressure differential forces the water to speed up through the restriction  ??
Chris

Yes, kinda.

But another way to look at it is that the difference in diameters forces the flow rate to be different - and since a pressure difference is required to accelerate the water to the higher flow rate the restriction - alternatively: the change in flow rate - creates a pressure difference.  B-)  Which is just the venturi principle again.

A pressure differential accompanied by a corresponding acceleration of the water is not a problem.  (It's actually what you want.)  It's when you have a pressure differential that DOESN'T produce a corresponding acceleration of the water that you're losing energy.  That's the friction along the sides of the tube.  That's why you want to tube to be big - to reduce the amount of friction surface per unit of water volume via the square/cube law.  (Actually the linear-square law when it's a cylinder.)

[kumaraken]

hi Karson
just seen where you said the guy you brought yours from may have another for sale, did you check it out. ihave finally found a new zealand distributor but they want $2500.00 nz dollars the prce at ampair in UK is 716.00 pound which is $1300.00nz dollars so they are putting quite a big mark up on it iam sure the freight  wouldnt  be that much.let me know  what you think
kumaraken

[greenkarson]

Sorry the guy i bought mine from never answered any of my emails about still having the other turbine.  But he was going off grid way out in the woods and that may have meant offline as well.  Why don't you just order it directly from  the UK?

[divemaster1963]

I know the covert setup was not the best but it was solid and seems to work pretty good.  Ideally id like to find a piece of a big plastic sewer pipe just slightly bigger then the prop and mount it inside the covert as well.  Right now there is almost 2 inches clearance all the way around the prop.
 thanks karson

Just a suggestion but check with your nearest towns water company or a construction supplyer. I have talked to ones around hear and they have lots of large PVC water supply pipes that gotten broken sections. they can not use or sell them and sometimes give them away because local landfills prefer not receiving them.
just an idea
I am waiting for the guy who owns the land just behind me to let me use the edge of his property to gain access to the creek that has constant water flow because mine dries up to fast.

good luck

[srh69]

hi Karson
just seen where you said the guy you brought yours from may have another for sale, did you check it out. ihave finally found a new zealand distributor but they want $2500.00 nz dollars the prce at ampair in UK is 716.00 pound which is $1300.00nz dollars so they are putting quite a big mark up on it iam sure the freight  wouldnt  be that much.let me know  what you think
kumaraken

Hi Kumaraken - just so you don't think us Kiwi's are hiking the price 716pounds is actually NZ$2150 (3 to 1).  This site may interest you http://www.ampair.com/ampair/waterpower.asp. cheers