Propeller Turbine

[Mark Parsons]

Being unwilling to pay about $2,000 for an Ampair UW-100, I have tasked myself with designing and manufacturing a propeller turbine.

The propeller is to fit inside of a smooth wall 15" ID pipe that takes a percentage of the creek flow. Since this pipe is in place the best way to do this is to collect another short piece of same pipe and build the turbine assembly at the shop. Drop the completed assembly in place on site and couple up with a repair flange.

I now have enough progress completed to start this thread and will add more as construction proceeds.

The first picture shows the brass 4 blade propeller (e-bay purchase $150), the servo motor PMA (almost free, salvaged from a dumpster by a member of this forum), assorted bearings and taper lock pulleys (Princess Auto $60) and the lathe turned aluminum propeller shaft (3 hours of my time). Not shown is the 6 SS spider legs for the bearing holders (another 3 hours of my time)

The second photo shows the empty pipe section that will become the assembly.

The third photo shows the propeller assembly with spiders sitting inside the pipe. The spiders are fabricated from SS tubing and plate.

I need to fasten the spider legs to the pipe wall. The propeller is 14" diameter. The pipe ID is 15.38". I was planning on putting 1/2" thick rubber material I have around the shop as a layer fastened to pipe inside around the propeller to constrain the space and make a fairly tight fit.

I was also planning on putting some straightening vanes upstream of the propeller to keep the flow impacting the propeller blades correctly. In my mind I'm thinking SS 18 gauge plate. Not sure if I have any of that around the shop. May have to settle for galvanized plate or wonder if 1/4" polycarbonate (Lexan) would stand up to the task?

The key non-corrosion resistant parts inside the pipe are the bearings. If all works well I will order SS bearings to replace the cheapies.

I appreciate any ideas or constructive criticism.

Mark

[Mario De Castris]

Hello Mark,

I figured you were busy building something since I had not seen much activity from you on the board. Very interesting set up. As you know my interest it's always been to eventually be able to do something with the water in front of my house, so I have acquired, from a friend, the lower units of an outboard motor that blown the head. The intention is to replace the propeller with a larger one and install a PM motor at the end of the drive shaft. I still have to figure out what the gear ratio is and also how much drag, maybe your idea is better. Some time ago Paul and I tried to spin the same servo motor on my lathe to determine the power output at what r.p.m. with not much success. Later I realized that we were trying to drive a 3 horsepower motor with 1 hp.

Mario

[Mark Parsons]

Hi Mario,
Would be difficult to load up a 3HP generator fully from a 1HP motor, unless maybe you can tap into ZPE (Zero Point Energy) ;)

If you could put a large enough propeller on the end of the outboard lower unit it should work to bring the power up out of the water through the driveshaft. Would need to know the water velocity to do some calculations for expectations from propeller sizes.

Found some old surplus tire retread rubber laying around the shop today. Has a nice bevelled edge on both sides. Lined it around the propeller and bolted into place. The pictures were taken prior to adding the bolts that will hold it firmly in place. Just need to solve the straightening vanes now.

Mark

[Rob Beckers]

Great project Mark! It'll be very interesting to see how this works out.
Knowing nothing about water propellers, I'll assume they work the same way as those in air. So there probably is an optimal RPM vs. water flow speed, just like TSR for wind turbines. Do you know what it is for your prop?

-RoB-

[Paul Bailey]

WoW Mark> Love it,interesting design and you have the perfect application except for maybe a little more head but I think you'll be impressed with the results on this. My hydro calc says there is 267 watts available, not the 50 as posted..Paul:)

[Mark Parsons]

Hi Rob,
Thanks for the input.

Boat propellers don't use lift as far as I know. I've never seen TSR as a reference to water propellers design. Since water won't rarefy(sp?) much without creating cavitation bubbles or easily compress maybe it is difficult to design a water media lift type propeller? Perhaps someone with more knowledge on this can chime in.

A boat uses the propeller as a screw to mechanically screw through the water. A pitch slip loss of about 5% is used in the formulas to indicate it doesn't screw 100% efficiently like a screw into wood.

This brass propeller was designed for a wake board / ski boat application. Lots of power transfer at low RPM to get the skier up early. It has an 18" pitch. Based on that, factoring in a 5% pitch slip and 1:1 gear ratio it should be turning my PMA at 80RPM (12VDC cut-in) at about 1.6MPH water flow.

I know Turgo and Pelton wheels have specific speeds based on jet velocity and runner diameter. I don't know of any specific speed for a propeller. The water velocity in my culvert will increase with head. Doesn't take much head to create 1.6MPH.

Hi Paul,
Thanks for the feedback. Your scrapped servo motor will live another life.
What other parameters in your formula are you using to get 267 Watts?

Regards,
Mark

[Joe Blake]

I'm not hydro-literate at all, but this looks an interesting idea.

http://www.gizmag.com.au/bourne-energys-riverstar-current-electricity-generators-the-new-face-o/8922/

Is this old news or new news?

;)

Joe

[Mark Parsons]

Hi Joe,

I saw the Bourne Energy concepts earlier this week. There are some serious skeptics on the Microhydropower.net forum.

Appears much of the physics is ignored in Bourne's pictures. For instance in their 10kW river star device, the bouyancy and design would not compensate for the torque created in 10kW. With the propeller turning 60RPM (likely in 4 knot current) Torque to create 10kW of power is 1,173 foot-pounds. The design must constrain this torque.

Regards,
Mark

[Mark Parsons]

Well, the pipe interior work is now done. Fabricated and installed the Guide Vanes just upstream of the propeller. This keeps the water from swirling down the pipe detracting from power harvest. 1/8" SS plate worked out satisfactory. Photo shows them in place.

[Jeff Birkle]

Looks like your getting there!
I'll post a new link with a picture of my turbine-water wheel.
Jeff

[Mario De Castris]

Hello Mark,

It's been a while but I've been following your progress with a lot of interest and patiently waiting for spring for the deployment of your new turbine. By the pictures you posted I am assuming that you plan to mount the servo motor above the water through a belt system which will give you a way to manage r.p.m. and keeping the motor away from the water, I am sure you already have all your ratios calculated.

Mario

[Mark Parsons]

Greetings Mario,

I too have been waiting patiently for spring to arrive!!:eek:

Picture below shows the PMA (servo motor) now installed. Gravity holds the tension on the belt using a pair of large gate hinges and an aluminum plate. The servo motor is mounted using SS gear clamps onto the aluminum plate offset from the hinge point to provide the belt tension.

Got in my pack of 10amp diodes from an e-bay supplier. Next job will be to wire up and install the 3 phase bridge rectifier circuit.

With any luck, installation at my site may happen later this month.

Regards
Mark

[Mark Parsons]

I have the propeller turbine at the cottage now.

However, I have some repairs to do prior to installing. The high spring water did some damage. It wiped out my bridge and breeched the causeway at the culvert. So before installing, the water needs to recede, and the causeway breech needs to be repaired. The bridge is another matter.

A photo of the bridge as it was last weekend. One log remains in place so just need good balance to cross... :rolleyes:

[Rob Beckers]

All that energy going to waste Mark... That turbine should be in the water! :D

Judging by the trees sprouting from the water it must have risen quite a bit. How much space is there normally between the bridge and the water? The Rideau River (and canal) here were also at levels I've never seen them before. Then again, I've only lived here for 2 1/2 years. There was some minor flooding along that river; all in all people were lucky considering how quickly the snow melted (and the rain on top of that).

-RoB-

[Jeff Birkle]

Whats the good word.
All the repairs to the dam done?
New turbine in, making lots of power?
If you want you can bring it down to my place one day and hook it up to my culvert to test.
Too bad my excavator and dump truck can't make the trip up to your place.
Jeff

[Mark Parsons]

Whats the good word.
All the repairs to the dam done?
New turbine in, making lots of power?
If you want you can bring it down to my place one day and hook it up to my culvert to test.
Too bad my excavator and dump truck can't make the trip up to your place.
Jeff

Hi Jeff,

No repairs done yet. So no turbine in yet. Thanks for the offer of testing at your place. This spring I have had a few setbacks. I plan on floating my tractor up there in a couple of weeks. Then I can get the repairs and installation done pronto.

Photos will be forthcoming upon installation.

Take care,
Mark

[Dennis Buller]

Hey Mark,
Oustanding project!
I do have a couple quetions though.
Are you worried about slippage on the "V" belt with it in the water?
Have you looked at extending the pipe and making the opening bigger to try and create some extra pressure/speed? (more water+smaller spot=higher volocity)
Are you concerned about flood water submerging the generator?

[Mark Parsons]

Greetings Dennis,

Glad to see you post on this forum! Thanks for your positive feedback.

Are you worried about slippage on the "V" belt with it in the water?
With the experience gained with the Banki turbine (V-belt was wet), the small amount of power harvested that is mostly non-fluctuating doesn't seem to create a slipping issue. The belt is rated to transfer 3hp, I will be transferring between 1/20 and 1/6hp.

Have you looked at extending the pipe and making the opening bigger to try and create some extra pressure/speed? (more water+smaller spot=higher volocity)
Not at this time. I am looking a making a trash rack at the pipe opening to try to stop sticks, (beaver activity) and other flotsam from binding the turbine up.

Are you concerned about flood water submerging the generator?
YES! The generator is attached with 3 band clamps. I can have it pulled in about 2 minutes. The trick will be to pull it before a flood submerges it. On my creek a flood of this magnitude is mainly only a spring event. I will likely pull the generator before spring breakup and re-install after.

I have my tractor at the cottage now, so am planning on getting the turbine installed on a weekend soon. My culvert pipe requires some re-positioning and re-burying after the causeway breech around it this spring. The water rushing through the breech in the foreground of the attached photo is above my culvert.

Best regards,
Mark

[Jeff Birkle]

Good to see things happening.
Look's like you have more water flow than I do. Do you know what you have for flow and head?
Trash rack is a good idea. I was up to my place 3 weeks ago, 9 weeks after the previous time (Maple Syrup season), and found a Turtle wedged in my Water turbine, stopping it for at least a few weeks. :(
It's a good thing I have a bypass in such a case, It did drain all my batteries because I keep the fridge on. I also unplugged to Solar array because I didn't need it (i'm still building a Load diverter).
My site is very weedy on the surface so I can't use mesh (it gloggs up), I need to build a set of horizontal wires to let the weed through but keep the big stuff out.

Does your servo/Alternator not do well in water? These Axial Flux Alternators i'm using can run under water if required, with epoxy paint coatings. They have no brush's or electronics. Once you know what output you can get, I can help you make one of these if you like?
TTL Jeff

[Mark Parsons]

Hi Jeff,

Things are happening albeit slowly.

I have the breech filled in again. Still need to mount the propeller turbine section.

Does your servo/Alternator not do well in water? It is a brushless PM industrial servo motor. There are no electronics inside. It is not submersible rated. Key damage from submersion would be shortened bearing life.

I had lots of flow when the photo was taken (spring runoff). I have 36 inches of total head over about 200 feet of run. The propeller turbine will only see about 15" of head.

Sorry to hear about your batteries. Complete discharge significantly reduces battery life. I installed a 75amp low voltage disconnect I bought from an automotive accessory store that prevents my batteries from going below 50% depth of discharge in the event of a failure or someone leaving a few lights on for a few weeks (its happened). I recall it costing me about $100.

I would still like to get together with you and compare systems this summer or fall. I am at my cottage most weekends.

Regards,
Mark