Having trouble searching on internet

[Harold in CR]

 I can't seem to get the proper jargon for asking my question. I get unrelated input.

 So, I plan to put a small dam in, to get a better route for the water to drop down to my micro turbine.

 I have 25 GPM minimum, and up to several thousand for short bursts, from drainage into the area. Normally, I'm getting around 40 GPM on a fairly steady basis, for 8 months or so, of rainy season. Stream is spring fed, and when a gully washer comes, it goes from a 22" wide X 3-4" deep stream, to 20' wide X 2 feet deep or more of rushing water. I can build for water going over the top of the dam, and, pipes going out the one side and down to the turbine.

 My question is, is it better to have the flow drop more straight down into the turbine, or, have the flow at approx. 20% drop for 100' of travel from the dam to the turbine ?  I will have 26' of head to the turbine.

 I know I have a minimal system, so, trying to squeeze every bit of power from what I have.  available.

[dnix71]

Put a pipe at the top of the weir and run it more or less straight down if you can. At the bottom where you have the max head install your turbine and have the output directed through a larger short pipe to where the discharge will not undermine the dam or turbine setup. The intake of the top of the pipe should be set up so there is no air entrained going down the pipe.

Arrange the overflow of the dam and the turbine install so they don't interfere with each other during high flows.

[Harold in CR]

straight down

This is the part I have trouble with. Do you mean in a straight line at an incline, from the dam (weir) to the turbine, or, nearly 90° vertical drop ? I can do either, so, want the max power available, IF there is a difference.

 Some things I just get hung up on, and, I can't afford to experiment too much, to KNOW what I need to do.  That outfall, thrust pipe is a definite to do, part of the turbine.

 I need to get serious on this project, because the dry season is approaching, and that is when I can build the forms and pour the dam.
 Thanks, David

[thirteen]

that might be determined what you will use for a trubine crossflow, pelton wheel? What I  will have is one that I can only use for about 8 months out of the year then my water will be to low. So I am making a solar / micro hydro duel system. There are times I only get an  hour of sunlight  a day during the winter 1/2 of Nov. all of Dec. Jan  then 1/2 Feb. I am going to try and move up there to my place on January 1, 2013. Just signed retirement papers and sent them in.

[SparWeb]

Harold,
The head will be there, whether the drop is vertical at the dam or at the turbine.  This is true with only a few reservations.  Most of the warnings come from the way to build the feedstock.  Narrow pipe, many elbows, fittings, and rough insides will all rob away the pressure you need.  So in simplest terms, you want to make the feedstock as straight as possible, and if a vertical drop at the dam is the way to do it, then so be it.  If the location of the turbine would make it convenient to make the feedstock a straight sloping run all the way, then all the better.  Just avoid if at all possible, extra joints, corners and so on, because the turbulence they introduce is a waste of energy that you'd prefer to use.  Same goes with using a feedstock pipe that's too small.  For the same quanity of water, the flow will be faster.  That will always make it more turbulent, and the effect of corners and joints is stronger, too, when flow is faster.

Will you be building a dam or a weir, in proper terminology?

Also, since terminology is tripping you up a little, maybe research "coanda screens" or "coanda filters", because there will be a lot of debris and sediment caught in the downpours.  There are other ways of keeping out the junk, that's just the first way that came to mind.

Good luck!

[Harold in CR]

 Thanks guys. I have nearly the same things to work around as thirteen. I have to build 3 solar panels with all the materials I have finally gathered, and oztules excellent tutorials.

 First thing is build the dam-weir.

 

Will you be building a dam or a weir, in proper terminology?

  ?? I have to DAM up the spring fed creek, to get elevation. That will give me nearly 8 feet of head, right there. Can't go any higher, so, I will insert 2-4" pipes into the top part of the DAM-WEIR.  I will also create a spillway, so the excess water runs over the top of the dam, and will be broken up into non-destructive forces, as the water reaches the terrain below. Bigger rocks, mixed in with cement will stop a lot of the erosion. The whole thing will be formed up and poured concrete with lots of rebar, and, anchored far enough back into the dirt walls on both sides, AND, lined with a large vinyl tarp-liner as I can afford, and it will be cemented to the dam, and run back, maybe 20' upstream, and covered with larger rocks, to anchor it. 

 I will have to get some photos, when the rains slack off some, so y'all can see what I have. It's NOT your normal dirt creek. It has a HARD Bottom, that should hold water as a small pond. Only reason to dam it, is, to get height. I can run the outfall pipes to the turbine, with not many curves or other obstacles. Drain pipe, in 4" sizes, with have the bell ends, so, that will not create too much turbulence.

 I am drawing out an Ossberger designed crossflow turbine. I have watched many videos of different turbines running, and, they ALL have a spray of water coming off the blades or spoons. The Ossberger uses a flapper designed to guide the flow directly into the blades, no matter how wide the flow entering the turbine. High water flow conditions, the flap will rise up and still deflect as much water as possible into the blades. It can also widen the pattern of flow, to allow more power to be produced, and regulate the flow as the high water recedes.

 It's more work and complicated than a Pelton or Turgo, but, I think it will be more efficient. The Pelton and Turgo, both get 1 strike of the water to the spoons, then you get lots of spray and turbulence, instead of getting a second and third effect like the Ossberger offers. Ossberger also claims to be able to run their smallest model for a 1KW system. I'm going to be lucky to get 70 watts at times, but, that's OK. I can build the turbine and alternator cheaper than buying a Harris setup, or designing a Turgo setup.

 Also, I can put up a wind turbine. I'm completely experienced in that, but, I'm not wanting to have to climb any more towers, being as I just turned 69 years old, a month ago. I have a 60"= 3 blade drive hub, and, I can build another 3 phase alternator, like is shown here, using some recycled coil wires I spent several hours unwinding and spooling. The wire is large enough, I will be asking for more calculations of RPM's and voltages, amps to wind the new coils and size the whole unit correctly.

 I don't NEED a lot of electricity. Normal usage is less than 400KWH per month, but, prices keep climbing and the power has many surge-dead-surge cycles, per day, maybe as much as 10 days per month. That's hell on refrigerator and electronics, so, I want to wean off the power company as much as possible. They do NOT encourage feed back here. I have to contend with the monopolies that pay the Govt. to stop competition, and allow the crappy service.

 SO, is it a dam or a weir ?? 

[Frank S]

construct something like this and place over the Weir the siphon will have the same flow for the most part no matter the  water level the inverted foot valve controlled by the float will not allow drawing from the very bottom this also prevents lowering the water level too far or loss of suction  I'm showing a 20 degree down slope which @ 100 ft length of pile would be about 30 odd feet of head
 if you know it is 100 ft to  the turbine and you have only 20 ft of head then the down angle would be much less

[Harold in CR]

 Like the idea Frank, BUT, this water flows through a very heavily vegetated area of trees, plants, debris. This is in a jungle setting, so, that intake would clog or, not seal correctly, or, allow debris to enter and plug up the pipe, I BELIEVE.  Don't know for sure.

 The coanda screen will be something I can build, so it sweeps the debris to one side and over the weir.

 I will have to take measurements of the distance and actual head. The day I did this, I used a 25' belt clipped tape measure. I now have a 100' tape measure, and, my wife to help me. I will take some photos and show what I have to work with.

 Just because I THINK something will not work correctly, I hope no one takes offense and will continue to add info for me. There is NO ONE here that knows anything, other than, No entiende. 

[dnix71]

I worked for the TVA, so I used the term weir. I sampled the water flowing over the V notch from package sewage treatment plants to see if it met discharge standards. If you have a dam that overflows regularly and you need to measure the flow a V notch is easy to calibrate and read. The V at the top also allowed a steady flow off the top so any biological matter could settle to the bottom of the tank and be pumped out as needed.

That kind of V notch would clog in a hurry if there was floating leaves and such. There were no trees near the package plants, so that was not an issue.

[SparWeb]

Frank,
Might be tricky keeping that pipe primed.  When the foot valve closes I fear the downpipe would empty, leaving no suction to draw the water back up above the reservoir water level.  If the downspout can be embedded into the wall of the dam, the same head is still there, no need to prime.  Total head at the turbine comes from the top of the reservoir water level, not the highest point the water flow reaches in the pipes.  Maybe it was just a quick diagram to show the valve, not the course of the pipe.

Harold,
The debris in your stream flow will probably be the driving aspect of the project, not the choice of tubine runner.  If there could be any debris getting past your screens and filter, for example, then you must pick a turbine runner that can reject it rather than get clogged.  That may rule out some runner types, though I have no experience to offer in that matter.  Furthermore, if there is enough debris to accumulate behind a dam wall and silt up the entire reservoir, then you need to consider the alternatives to a simple dam and design appropriately.  The proper design will shed most of the debris while still allowing you to capture and harness energy from the flow, weir, dam, spillway, whatever it takes.

[Harold in CR]

 I have constructed a small dam upstream from where I am considering the new one. It has always had overflow, IF the 3" pipe I put through the top board, 1 inch below the top of the board, got plugged. It did get plugged with leaves and sticks. It was not designed to be self clearing.

 There WILL be debris gathering behind the dam, so, that's why I was planning 2-4" through pipes at the near top of the dam. There, I could mount them at the near extreme edge of the dam, and angle the screen to shed the floating stuff directly over the top. Those 2 pipes will immediately go underground, through a hill that I have channeled through, then angle down, from the curvature of the pipe. No need for elbows or sweeps. At the turbine, I can go directly into it.

 This is where my original question originated from. Is it possible to gather more force from a direct nearly 90° drop from 28' into the top of the turbine, or, is it the same amount of force as the 28' drop, angled from the dam, steadily down to the turbine.

 If it's not too rainy tomorrow, I will get photos.

[thirteen]

Could you put your pipe to one side of the dam where there would not be very many leaves or other things would flow directly to the intake pipe but still have a good flow of water. Get some used shaker screens and build a large boxed in area around the intake to stop the leaves from plugging the intake. You would still have to clean it ever so often. It might help. It might be a hassle if you are in a very cold area where it could freeze easily. Just an idea.
13

[Frank S]

Frank,
Might be tricky keeping that pipe primed.  When the foot valve closes I fear the downpipe would empty, leaving no suction to draw the water back up above the reservoir water level.  If the downspout can be embedded into the wall of the dam, the same head is still there, no need to prime.  Total head at the turbine comes from the top of the reservoir water level, not the highest point the water flow reaches in the pipes.  Maybe it was just a quick diagram to show the valve, not the course of the pipe.

Sparweb it is usually easier to show a diagram sketch such as this in an abstract generic view.
 you are correct by lowering the highest point of the outflow  to a level below the natural low water level negates a system ever loosing prime as long as that level does not go lower. The float attached to the foot valve is to prevent complete draining of the pooled area the max setting for this would be set at Zero spillway flow or wherever.
 Maybe I should have shown it more like this. which may have clarified things a bit more.
 For the water turbine there should be as clean of water flow as possible, Without the mud a beaver dam does a terrific job of blocking debris the pool area under a beaver dam will contain some of the cleanest water of a stream pathogens aside. But we don't need to filter for drinking just debris removal so the pipe does not become clogged or damage the turbine

[Harold in CR]

 

It might be a hassle if you are in a very cold area where it could freeze easily.

 13, I live in the tropics. Only ice we get is in the freezer.  Also, sand plant screening is not readily available down here. I will use round smooth solid bar for screening. 2 screens, one ahead of the other, for second attempt at deflecting debris, and, yes, outflow pipes will be to the side of the dam, to avoid most debris and flash flood debris.

 PHOTOS

 After I post these, y'all can ask questions. Wish I knew how to add arrows and circles onto the photos, before I post them. Lets see if I got something.  I tried to outline in Yellow, the specific parts of each photo.

 I see there is no spacing between photos, so, we have to study each photo a little.

 1st photo shows approx dam height.

 2nd shows the dam height with the channel cut through the hill for the outflow pipes.

 3rd shows the actual dam location right below the bridge and just a couple feet upstream.

 4th and 5th photos show location of the original dam I build for testing my theory, and the arrow? shows the location of the property line- fence in the 2nd photo, so, I am very limited to how much I can back up the water, so it doesn't flood my neighbor upstream.
 
 6th and 7th show that same channel, but, it has caved in a little, so, will be cleaned out and about 8" lower than the photos show.

 8th photo shows a place I skinned on a fence post, that is 12' below the channel on the outflow side, and, from there it drops another 14' or so to the last photo that is the turbine site, just before the stream exits my property.  This allows the downstream neighbor to have access to the water, after it goes through the turbine, so, he can't complain, when the flow is not heavy enough to spill over the dam. My property is 50meters or 165' wide, approx.

 SO< this is what I have to work with. It isn't much, but, at a 24 hour a day flow, I hope to get approx. 60-80 watts per hour, X 24 hours = 1.5 KWH per day ??  Even more on good rainy part of the year.  Online calculators show approx. 36 KWH per month at 30GPM. I should be able to get around 45 GPM average during the rainy season, or more, depending on the rains being heavy or light.  That would be approx. 56 KWH per month.

 It's not much, BUT, I have already had to replace my computer twice, because of the crappy Power Co. system, so, at that cost, I can make this pay.  I also have a backup plan, to catch all the runoff of rain from the front of my property down to the pond I dug, and let that run through a generator or, pipe it into the existing system, and drain down the pond, whenever it gets topped off. IT holds approx. 9800 Gallons or so. It measures 4' deep X 12' wide X 45' long.

 I figure that would provide approx. 3.5 hours of draining, at 45 GPM. The head would be over 100'. That would add 1KW in a 3 hour session. That pond COULD refill within a week or less, sometimes.

 I have photos showing the elevations of the area, and it measures, 50M or 165' wide X 65M or 214' long draining into the pond.  I have seen this runoff try to cut ravines into my property, so, I have dug small channels to break up the runoff, into several small diversions. IF I run the runoff into lined channels, it's amazing how much water there is. Here, sometimes you can't see more than 100 yards through the rains.

[hydrosun]

/as for your original      question the amount of power available   is determined by the total head minus any friction losses. So the biggest pipe, least sharp bends with the shortest distance will give you the most power.
you may want to consider your goals with this hydro. Do you want the maximum power at high flow times or the highest efficiency   at low flow times to ensure a minimum amount of power. One turbine can't do both. You could do more than one turbine to     maximize both. A small pelton for low flow and the cross flow to take advantage of the higher flow. At the highest flow the size of your pipe will be the limiting factor. The four inch pipe will be limited to        under 200  gpm. I'm not sure how efficient the crossflow can be     under partial flow even with nozzles directing the water       to the center. There isn't any sides to prevent the water from spreading out and not transfering it's energy to the turbine. A turgo may be a better fit for the amount of water that can be moved with your 4 inch pipe. Either multiple nozzles or a spear valve. I just bought on on ebay for $150 that I will be experimenting with.the difference between a weir and dam is the height and whether for storage or directing water into an intake. The rules for a dam can be stringet so calling it a weir with less impact can sometimes make it easier to get permissions if needed.
Chris

[Harold in CR]

 Thanks Chris
 I know you have tried to advise me on this quite a while ago. I have added more photos and info since you read this thread. IF you have the time, please reread the last post I made, then we can get to the rat killing. I will try to find info on the efficiency of the Ossberger turbine, in the meantime.

 LINK

 Viewing the website, it gives a chart of specs. Also, it shows a drawing of how the turbine is designed. I WILL be putting the blades slightly inside the max diameter of the side plates, so they will contain any possible splash, where the Pelton and Turgos waste some of that "splash" power.

 Couple of statements from Ossberger website.

 The mean overall efficiency of OSSBERGER turbines is calculated at 80% for small power outputs over the entire operating range. These efficiencies are normally exceeded. Efficiencies of up to 86% are measured in the case of medium-sized and bigger units.

 On a free-stream turbine with a wide operating range therefore the suction water column must be controllable if the turbine is to be constructed as a draft tube turbine. This is achieved by means of an adjustable air inlet valve which regulates the vacuum in the turbine casing. In this way even heads of as little as 2 m can be fully utilised by OSSBERGER draft tube turbines.

[hydrosun]

I looked at your link. I now understand the design of the turbine has cross plates on it to create cells to be able to use smaller flows efficiently. I didn't look at all the specs on the range of flows it could accomodate but saw it said 6 to 1 range. Your low flow is 25 gpm and your two 6 inch pipes could move over 400 gpm so that is 16 to one.
So again I ask what your      goals are. To maximize the efficiency at low flow or get the absolutly most power at high flow. The pipe and turbine to handle the full flow at flood would be expensive so you have limited to the two 4 inch pipes and then the limit is the width and diameter of the cross flow.  Peltons might look like more splash but they can be above 90% efficient if the rpm is matched correctly. The crossflow works under vacuum so it looks like it has less splash but it all boils down to transfer of energy from the waer to the turbine. The pelton completely reverses the direction of the water 180 degrees while the cross flow turns it  partially in each pass.
You might want to ask Hugh Piggot at Scoraig for more info on crossflow turbines. I believe he has direct experience with using them. My experience is with pelton and turgo and just theory of crossflow. Hugh taught the hydro workshop for SEI thhis fall that I helped out on. I think he would be willing to answer direct questions by email. In the past I think he watched this site also.

[hydrosun]

i just saw that you also have a pond site with 100 feet head. You can run it through the same turbine but the efficiency will be much lower because the rpms at peak efficiency is about double the 26 feet head. I've done it before but went to two separate turbines to get higher efficency. It depends on how much you want to spend on the separate system for 3 hours of  extra power every few weeks. As i tell people almost anything is possible but it worth it to you to spend hundreds to save pennies. So if you spend some money to get the most efficient power users then you don't have to produce as much power. I'm on line with my tablet running directly on 12v with 12 volt leds lighting overhead.      So the load is minumum without the need for inverter losses. Of course my hydro is going at max so I would need to be frugal right now, but when it dries up I don't need much solar or battery to keep the baseline loads going. So you may look at baseline loads that can be run on the 1.5 Kw at low flow and then decide if it is worth while to you to oversize to capture the high flow for limited times. Efficient lights, computing tvs refrigerator can be run on the 1.5 kw. I work on one hydro that puts out 45 watts year round for lights and electronics. But he pumps water with gas engine and has a propane fridge, but could run everything on the hydro system if he set it up efficiently. That system has 22 feet head 300 feet 4 inch pipe and an ESD turgo turbine. His stream flow is from 50 gpm summer and thousands of gallons at times in the winter. He could produce much more in the winter but  chooses to keep the intake simpler without having to deal with more water. He just has several feet of screen at the end of the pipe. To handle more flow you have to clean more often or allow bigger stuff to flow through or have a much larger screen area that is more vulnerable to damage by high stream flow. At one time he constructed a 4 foot high rock filled dam but the stream took it out. He now has a low dam further up streamwith a bit more pipe.
This las summer I built a 1 foot concrete block weir intake with coanda screen. Had some leakage through the pourous soil in the banks of the stream. I know you wrote about using a sheet of plastic to seal but remember the side walls too unless it is clay.
Chris

[Harold in CR]

 I see what you are asking. I don't want to do the total amount of flow available at high rains flow rates. If I could size the pipes at the turbine, reduce the outflow, I would like to get max available at low flow, and double or triple that at higher flow. Any flow above that goes over the dam. I will be charging batteries, so, no chance of backfeed into the Power Co.  Absolute low flow will not be usable. When I took the photos this morning, at 6AM, the upstream neighbor was washing down the dairy operation, and, they have walled up the spring and put an electric pump in, and pump the water way uphill, to use the gravity flow to supply wash down pressure. The flow you see in the photos will be nearly ½ again as much, when the pump shuts off.

 Distance from the dam to the turbine is MAYBE 80' or so. Not that expensive, and, part way will be placed IN the ground, if the tree roots are not too bad. Normal white PVC I think would handle that the 160 stuff with the bell ends. A couple screws in each bell would insure to not have any blowouts.

 We are currently waiting to hear from a business deal, so, after a couple days, we can go down and get actual measurements.

 Is there anything you can see that I have not thought out sufficiently or correctly ??

 I will try to contact Hugh Piggott. Thanks again,  Harold

[Harold in CR]

Posted at the same time you did, Chris.

 I could just drain down the pond into the area behind the dam, and let the adjustable turbine handle the extra flow. Wouldn't be that much dumping with a 4" pipe.  or, necking it down to 2" discharge.

 I also thought about dumping the pond to 50' down the hill, through a turbine, then, running the outfall down to a waterwheel pump, to pump the water back up to the pond. Labor is cheap, ME. I'm retired. Wife does what she can to help. Pipe is not that expensive to put in 100' runs.

 I priced a Harris rig. It would run me about $1700.00 to get it shipped down here, then run the pipes and stuff. That was a year ago.

 I like to build stuff, so, I already have the 2 side plates for the turbine, and, a half sheet of 3/32" steel plate for the turbine. I have 1" and 2" solid bar long enough for the axle shafts. I have recycled winding wire for the Alternator, so, need pipe, magnets, Blades, bearings, power wire, and the concrete dam.

 What I would like to do, is, power the computer and TV off 12V, without an inverter. I'm pretty sure it can be done, just don't know electronics. I already have experimental LED lighting over my desk, and, 40 more LEDS to mount up. Also, just bought a roll of that Chinese LEDs that someone is using wrapped around wind chime tubes. We don't NEED bright lights, except to illuminate for guests in the house. I have built 2 plastic normal base size LED light bulbs. Used 4 of my LEDS in each so, I can screw that into a normal socket base that I will wire up later on. Great for floor or table lamp conversions.

 I'm also in contact with a couple of guys that have built ORC devices. One is getting sufficient power to run the machine and also get a small electrical charge into a battery. Haven't heard from him lately, but, I don't NEED another project right now. 

[hydrosun]

You can put two pressures into one turbine but you won t get the highest efficiecy but still more than you would by wasting the head and dump it into the lower stream. Just dont expect more than 30% efficiency. If you run that extra only when you can use the power instead of trying to charge a full battery you,ll get the most out of that resource. Come to think about it that applies to any power you produce. In and out of the battery loses some power.
There are many things that can work directly from 12 volts, check the rv market. My system started at 12volts and still has most lights at 12 volts. The refrigerater has 12volt danfoss compressor that replaced the original.  I have a radio with 8 batteries that I hooked up 12v in the battery compartment. Some smaller led tvs work on wallworts that put out 12v and will work off your battery bank. Some things will only work on an inverter but can be on a plug strip so the inverter can be in search mode or shut off most of the day.
Chris

[Harold in CR]

 Excellent info. I have 3 UPS's I can use with 12V. I'm not into needing auto sensing. I can switch one on and use it until I need to shut it off. I really just need to filter the Power Co. when they have these on-off-on-off, etc., etc., moments. That's what fried our last TV. Been without one for 3 months. Nice and quiet around here, usually. 

 Would love to have an alternate fuel refrigerator. Had a Servel in our Arkansas house, hooked to our 250Gallon Propane tank. Thing worked great. Don't exist down here. 

 OK, believe I have enough ideas to ponder over and get set up for concrete pouring. It's a LONG slide down to the creek, so, I need a practical way to ferry gravel and steel and bags of cement. I can cut a tree right near the area for forming the dam.

 I've got plenty of hard lumber, so, I;m thinking about a track, in a "V" shape, build a box that rides in the "V", and slide stuff down, and winch the box back up. This very hard wood gets slick fast. 

 I'll try to keep y'all up to date. Right now, I have to get my solar panel oven built, so I can make 3 panels. Sun is finally showing up for a few hours per day, now.

 Got to get more batteries, also.