Plastic Barrel VAWT

[feral air]

The ultimate goal is to pump water from a 60' well and to do that I'd like to use the air-lift pump method.

I got a pretty sweet deal ($30ea.) on some "used-once" plastic 55gallon barrels and am trying to make a VAWT from one. The barrels are closed-top (no lid) with 2, 4" bung holes opposite each other. The mold-line runs right through the center of the bung holes. I cut the barrel in half along the mold-line yesterday. Then I moved on to testing joining methods...

I found some plastic adhesive (2-part mix) for $35 online and there'll be plenty of leftovers. I thought about getting a plastic welder but I'm trying to spend as little as possible (being frugal, not cheap and I've never used one before anyway so I'd have to practice a lot. Using the adhesive, I test-joined two scrap pieces of plastic barrel (from an old unrelated project) but it didn't hold for squat. It turns out that wiping the excess dirt off with your t-shirt doesn't count as "rough up and thoroughly clean the surface"...heh. It turns out that the directions were on the inside of the box and I just found them - I tried again, this time using some rough sand paper and PVC primer (it was handy) before applying the adhesive. It should be set by lunch tomorrow so we'll see how that works.

The plastic adhesive won't need to keep the two halves together by itself but it would be nice if it has at least some strength. I plan on using those same scraps (cut to fit) for reinforcing plates and will bolt the two halves together...with the adhesive in the gaps and between the sheets, so to speak.

Anyway, with it cut in half, I put it in an S-shape, lining up the half bung holes. This gives me a 4" center hole (for the bottom) and leaves a nice gap for air to flow from one vane to the other. The 4" hole is also the perfect size for a bike wheel hub. I'll need to drill the other side and fit another hub but that's then. If this doesn't make sense, nevermind...I'll see if I can't post pics later.

Once it's together, and assuming it works, what kind of power should I see from this kind of VAWT do you think? I figured since it weighs half (25lbs, including the hubs) what a steel barrel does it should spin up easier, at least. I dunno, would I be lucky to get 1/8 HP in 20mph wind?

Oh, does anyone have any ideas for a small compressor I can drive with this? All my searching seems to bring up 300psi (no cfm spec) DC units on ebay. If I did my math right (doubtful) I'll only need about 40psi but the more cfm the better.

This is only my third vawt and way bigger than I've tried before so any input is much appreciated.

[ruddycrazy]

For an air compressor get and old but working 2 stroke lawnmower motor, plug up the exhaust and carbi inlet/outlet with a bung and seal it with plastic steel. Now the one I did had 2 1/4" bsp tapped holes in the head so I setup a simple valve on each using some air fittings, ball bearings and springs. Thats the easiest way to make a small compressor for next to nothing and the one I made put out some air nicely but the piston rings were shot and silly me got the new ones I made stuck in the exhaust gallery and the block ended up in the bin. But even with leaky piston rings it proved worthwhile getting another motor as i intend to do the same thing only I'll use some 44 gallon drums 3 high as a S type savvy.

Cheers ruddycrazy

[chadking]

It sounds like you are working on a real project now.  How many barrels are you using on this VAWT?  Just the one S, or are you stacking 2 or 3 on top of each other in stages?

As for connecting them together, good luck with your plastic adhesive.  It might help, but like you said, I would use it in conjunction with reinforcement junction plates and bolts.  Under a strong wind the structure is going to be under a lot of pulsing pressure from all directions.  Are you building a frame for the VAWT, or are you just using an axle and guy wires to the ground?

Regarding power, you will need to find someone with actual experience to get you some figures.  With a drag style VAWT, it is harder to figure the available power than people will let on.  That said, the swept area of this type of VAWT is smaller than you would think.  I've seen claims that are obviously too great to be believable, and other people state that you can't get enough power to make it worthwhile.  

There are a lot of people using them to pump water. So if you are going with 2 or 3 barrels stacked, and you get it up in the air to catch a decent wind, you should be able to pump your water.  But hopefully someone with more knowledge will come along and give you more details.

Good luck!  Take pictures as you make progress!

[electrondady1]

it sounds as if you are simply glueing the overlaping edges.

you will need some sort of support structure that will transfer the torque to a central shaft .

once you have a shaft turning you can decide on how to make use of the rotation

a drawing or photo would help.

[Stonebrain]

hi feralair,

I think a compressor is not the easiest way to go.

You should not only look the psis but also the power it needs(watts)and rpm.

Your vawt will be slow so you for a compressor you need to gear it up a lot.

The power of your vawt will determine if it can power a compressor.

You can estimate the power from the swept area and the windspeed,and guessing the efficiency of your rotor(better be on the low side).

Personally I would rather go for an old fashioned piston waterpump mainly because it can work at very low rpm's.

Again,you have to do some maths to estimate the right geometrie for the pump.

You have to play around with diam of piston (the bigger the diam,the bigger the force needed to lift the watercolumn),

the height the water have to be lifted(the piston will need more force to lift the water if the watercolumn is higher),

the stroke(the longer your stroke,the less force available for lifting the column),and so on.

Anyhow whatever way you go,you can't escape some maths,in figuring out howto tranform the power from your vawt in usefull movement

Doing this right is likely the hardest part of this kind of project.

I'm really interested in a vawt waterpumpconfiguration.

Keep us informed about the way you go,

cheers,

stonebrain

[wooferhound]

Here is a guy that made a usable compressor setup for his wind turbine

http://www.fieldlines.com/story/2006/1/9/103933/9137

[feral air]

Just the one S for now. I've got a couple more barrels I can add if I need to but I don't want a huge tower structure and my average-gallons-per-day goal is really low...I'm really hoping I can get by with one S.

I've got some steel tubes together to make a set of monster forks to hold the rotor and I'll reinforce the forks with some light rebar. For a mental image of the forks, imagine if you had a wheel that was 3ft wide on the front of your bicycle. Yeah, kinda like that. I'm hoping the monster fork idea works but I've got plenty of tubing in case the rotor needs more support.

The rotor and forks together will only weigh about 50lbs (assuming the forks work) so I plan on using a large diameter galvanized steel pole for a tower. The top of the pole I have is threaded so I can extend it up to 35' (w/o permit) if I need to. Guy wires only if I have to.

I'm planning on using bicycle wheel hubs for bearings. I'll use a rear wheel hub on the bottom to transfer power and a front wheel hub on top. They're cheap, available, easy to work with and gearing (even if it's fixed) is easy too. I had thought about getting an internal 3-speed hub so I could rig up a shifting mechanism based on rotor rpm but that's not gonna happen this version.

The vanes are 36" tall, 15" wide. What I'd really like to see is about 1/8HP (about 93watts) in a stiff wind. The cheap DC air compressors you can find on ebay draw about 70watts, iirc.

I'll see if I can't post some pics tonight. Thanks all around.

[thefinis]

I have to ask before recommending any thing. How deep is the water standing in the well? The best depth recommendation for standing water in an air lift water pumper is 2:1 so if you need to lift 10 ft(10ft head) it is best to have 20 ft of standing water over the air valve at the bottom. There may have been some improvements since I last looked that have changed this but it will pump less water with the same air as you decrease the ratio and I am pretty sure that anything less than a 1:1 ratio will not work. The more the head the more ratio you need due to water sliding around the air bubbles as it lifts and the air bubbles being compressed by the pressure in the lift pipe.

Finis

[feral air]

My first idea was to use an old fashioned piston waterpump. Doing some reasearch squashed that idea quick. They're pretty expensive and my water is semi-abrasive (fine sand/clay soil). I'd end up having to service the thing every other year and that would mean pulling the whole thing up out of the well. That sure doesn't sound like fun to me.

With an air-lift, all the moving parts are above ground, are fairly easily serviced and never come in contact with the water. And it can lift thin mud...at least in theory. Those are huge plusses and the deciding factors for me.

I don't mind having to gear it - I figured I'd need to anyway. My other drag-VAWTs run at about 300rpm so that's kind of what I'm expecting from this one.

[feral air]

I'm not quite sure I get what you're saying but the water level is about 18 feet below ground at its worst. I'll also want to pump up another 12 feet above ground. So that's a 30' head, right? Would I need to put the air line in at the 30' mark on the lift pipe or would I need to put it lower? I thought the idea was to put the air line in about 10-15 feet up from the bottom of the lift pipe.

If the well is 60' and the head is 30'..that's the 2:1 I need, correct? tia

[ruddycrazy]

Hiya Feral,

           Eh mate the bore I intend setting up some day is 55 metres deep with the water at about 15-18 metres from ground level. It's a 3" uncased hole and I intend to use the air well system too. Now my idea of using the lawnmower motor/s as air compressors will be my first go. I intend to put a non-return valve on the air line so any air pumped down the 1/2" tube will come out the bronze diffuser down the bore. When i tested the bore I run a hose from my shed air compressor and the outlet pulsed water into my front dam continuosly for about 4 hours till I turned it off. My idea of just using a wind driven compressor is aslong as the wind blows I'm pumping water and I'm thinking the outlet can go straight into a ram pump so I can transfer the water aroung the hill to stock water tanks etc.

Once i did see a pic where a bloke mounted 3 44 gallon drums as a S type savvy, had a car diff coming directly off the genny output and had a water pump on each end of the diff.

Cheers Bryan :-{)

[thefinis]

If the well is 60' and the head is 30'..that's the 2:1 I need, correct?

No you only get to count the depth of water from water level to where the air valve is in the pipe around 40 ft of standing water.

Sounds like you have plenty of standing water to get it to the top of the ground. I would put the air valve as deep as possible to get the most lift. Like I said it has been a long time since I researched them so unsure what the makers install recommendations are now days. For 18 ft of head(ground to water level) you should have the valve 36 ft below water level for BEST flow. It should lift the other 12 ft above ground but it will cut flow especially in low wind/low air flow times. The amount of air flow for pipe size will also determine the lifting ability. For more lift use a smaller pipe or a larger air flow. (general rule of thumb but if you are using so much air that it blows the water out the top of the stand pipe it will not help much)

They seem to be very low up keep and the two (Bowjohns?) around here I know of were working last time I looked. One had to replace blades lost in a high wind and checking the oil were the main upkeep items.

If you want a pumper type and can convert the rotary motion into linear(up and down) a setup can be made from pvc. You use 2" pvc for the main pipe and sch 80 3/4" for the sucker rods. You put a pin or bolt across the 2" near the bottom and drop a 1 7/8" check valve with its leather down the pipe to sit on the bolt and attach the 1 7/8" pump valve and leathers to the bottom of the 3/4" threaded sucker rod. It will wear the pipe some but is very cheap to replace and only needs to be in a few feet of standing water.

A quick fix and pretty cheap too for small amounts of water is the old style hand pump. It should work well with your water depth 18-20 ft and it only takes human power to operate.

Sorry for the long post but water pumping is something I have played with my whole life.

Finis

[feral air]

I saw that same 3-S setup, pretty amazing.

I did a quick sketchup of how I want to put my system together. It's not to scale or detailed at all, just the overview of how it should go together. Don't laugh, I'm not a graphic artist...

This way the water should pump as long as the wind blows. If the tank is full then the float switch will send the water up a few more inches and then back down into the well. No mechanical wizardry to stop the turbine/compressor either. It just keeps going and going.

[feral air]

'nother pic...

The reinforcement plates aren't cut yet so those aren't shown. I'm gonna replace the top and bottom pipe with galvanized steel (like what's on the left) and may make it a full rectangle support. If I can't get the replacement pipes cheap then I'll reinforce the ones shown with rebar.

[electrondady1]

 that clears up a lot

 on a savonius you need more over lap than that to get the boost .

i think its 20% overlap

researh that.

it's unclear how you intend to  harvest the energy

if you fix a full lengh  axel to the vanes via bottom and top support plates

the bearings would need to be fixed to your "forks "

they then become the top and bottom pins

you can run a pump direct off the shaft or to a pully or gear.

three or four vertical support pipes tied to your bearings with horizontal bracing would give a rigid structure .

[electrondady1]

can you weld?

[feral air]

The overlap is supposed to be 18% but what I've got now is convenient. I'm not worried about it since there won't be a shaft obstructing the air flow.

To harvest the energy I'll attach a chain to the bike hub (shown/mounted at bottom) and then connect the chain to a compressor (after putting a sprocket on the compressor shaft of course). I'm looking into getting an internal 3 speed hub instead of using the hub I have since I think it'll fit better.

Yeah, I can weld. My brother is better at it than I am so I'll probably just have him do it for me. Nothing I've welded together has come apart but he's had more practice and his welds look nicer.

[feral air]

I was out of town all weekend but managed to get the reinforcement plates cut. I got 3 of the 4 plates bolted on (dry-fit) but I need a larger hole-saw bit for the drill. It feels like it's all one piece now - solid. I'm hoping I can get the rest of the stuff I need to put the bearings in this weekend.

Slowly and steady.