Energy Matters Forums

[mikef]

I would seriously consider gate valves instead of balls.

Gate valves disrupt the flow too much with resistance in the gate. When fully open the gate sits into the water flow and stirs it up. Ball valves when open have a clean flow straight through and improve the efficiency of the jets onto the turbine. I am sure it is not much but over time it adds up. For example. If I was to lose just 1% of my energy (just 10 W amounts to $20 a year). That adds up if there are multiple losses throughout the system.

I'd love to call in and have me a sticky beak at it. I'm hoping to spend a week doing recon in Tas sometime mid Feb.

Have PM'ed you my details

[Warpspeed]

Large hydro plants generally use Pelton (high head) or Francis (medium head) turbines however Kaplan (low head) turbines are also used.

This is indeed true, its a pressure versus flow problem.
Francis turbines look pretty good for efficiency but the very complex compound curved blade shape, and the design of the outer scroll feeing it are extremely complex.

Something I have never seen tried is the adaption of a turbocharger exhaust turbine to mini hydro application.
Guess what, it has the exact identical blade and scroll design to a Francis turbine in minature.

Not only that the turbo exhaust turbine is made from austenetic (high temperature stainless steel) and will never rust or erode. These are really beautiful precision made turbines in a very small size.
Older turbine housings are raw cast iron and rust badly. But since about 1970 exhaust turbine housings are cast iron that contains a lot of nickel, so they no longer rust.

I sent a turbocharger turbine over to a guy in the US to try out on his own mini hydo. Never heard from him again. I think he may have had a heart attack or something. Never posted anymore on any of the forums, he simply dropped out of sight.
A real pity, I was becoming pretty excited about the idea.

If you look at pictures of the huge francis machines, and pictures of turbocharger turbines, they are identical in every respect. The physics is identical, and turbos have been developed to very high efficiencies.

[Smurf1976]

I'd love to call in and have me a sticky beak at it. I'm hoping to spend a week doing recon in Tas sometime mid Feb.

Whilst I understand that you're going to look at micro systems. But if you'd also like to have a look at some bigger ones then:

Trevallyn Power Station is a fully operational hydro scheme very easily accessible being in suburban Launceston. There's a private company (not the Hydro) that runs regular tours of it and they cost $35 per person. Trevallyn has 4 francis turbines and a fairly high load factor - you'd be unlucky to find all 4 machines idle on a tour (though no guarantee is offered that they will be operating - it would be unusual for Trevallyn to be idle during business hours however).

Waddamana "A" is a disused power station in central Tas that's open to the public as a museum. The original machinery is all still there (and there's also some equipment from the old Shannon Power Station as well) and there are machines with covers off so you can have a proper look etc. Waddamana has a total of 8 pelton turbines, two of which are 3.5 MW and the rest are 7 MW so it's all quite small compared to a modern power station. It operated fully from 1916 until 1964, being closed as such in 1965. Admission is free if you just turn up. There's a tour company that runs tours too, although all they are really doing is providing bus transport for a rather high price so you're better off just driving there yourself (road is gravel but good enough for any normal car). Waddamana is open every day except Christmas Day and Good Friday, 10am to 4pm.

How to keep rocks etc from going through the turbines? The intake at Poatina (on the north-eastern corner of Great Lake) is currently very clearly visible. Just turn up and have a look. Road is sealed except for the turn-off to the intake which isn't far from the highway. A small amount of walking across the shore of Great Lake is required to get to it - you won't get wet feet but need moderate fitness.

And if you want to see some serious pipelines and particularly surge towers then just head to Tarraleah (fully operational). The station itself is normally closed to the public (there's an open day once a year or so) but everything outside is clearly visible and the surge towers on the pipelines (near the township, at the top of the hill some distance from the actual power station) are huge to say the least. Plenty of penstocks and pipelines to see there. Road is sealed all the way from Hobart.

And if your hydro-electric aspirations extend to canals then just turn off the highway south of Tarraleah and head to Butlers Gorge. You'll get a very close view of the Tarraleah No.1 canal both the in ground and above ground sections as it's literally right beside the road practically all the way to Butlers Gorge (where the dam is). Road is gravel but suitable for 2WD cars without problems.

[Chaff_Cutter]

Cheers for that Smurf!

Have jotted them down and if I'm in the area I'll def. call in for a sticky beak!

Scotty

[karlajensen]

Nice solution to the tub being too flimsy and degrading in the sun....

hats off to you!

Have you replaced the shaft seals/ bearings recently?? once the seal goes bearings have a short life, have seen shafts worn out by the seals too, but thankfully they are free.

Also note you should do the nut up tight, by means of using spacers under the magnet hubs (once you've found the sweet spot.

also jealous that wind is so much harder as you need to be able to use a wide variety of winds not simply tune it for one spot....

Last...... if you can find a 100S stator, they will work out of the box on 48V, or if you're going to rev it that hard 8-900rom (magnet hubs should be at least balanced) you might even get away with halving it.

None the less i'm HIGHLY surprised you're getting that much power out of the F&P, in my experience with wind turbines very hard to get more than 350W out of a single motor.

[mikef]

hats off to you!

Thanks Karl. Its a pleasure to look at when its producing power.

Have you replaced the shaft seals/ bearings recently??

No. Bearings and seals still going well which has surprised me. But then the seals are wet which probably helps. One machine has now been going for 2 years (although it was stopped for a few months over our last summer as it was very dry)

Also note you should do the nut up tight, by means of using spacers under the magnet hubs (once you've found the sweet spot.

Haven't needed to. This system is not subject to gyroscopic precession like Wind Turbines. Hence it can sit somewhat flimsy on the end of the shaft.

Last...... if you can find a 100S stator, they will work out of the box on 48V, or if you're going to rev it that hard 8-900rom (magnet hubs should be at least balanced) you might even get away with halving it.

Great advice. I have been looking for them but in my experience to date, they are not that common at the tip and beggars can be choosers

None the less i'm HIGHLY surprised you're getting that much power out of the F&P, in my experience with wind turbines very hard to get more than 350W out of a single motor.

Water under pressure is great stuff. It has a lot of push and we run the machines at a much higher higher rpm.

When demonstrating the system to people they are a bit confused how a humming drum makes power. Then when showing them the washing machine in side, which they recognize straight away, they are then confused about the water part. I then demonstrate how much water under pressure it takes. I power the water straight from the open tap first and then with a larger jet attached next. I squirt this out into the forest and then they realise that 5 liters a second at 282 kPa (41 PSI) looks like quite a lot of energy. It is very impressive to watch.

[Peterf]

From Mikef's dad.
During the trialing of the F&P's we ran one with larger jets and full magnetic flux (screwed down tightly) and achieved around 850 watts. We assumed the stator wiring at under 1mm was fully loaded and wasteful of energy. Hence the second trip to the dump and a couple more F&P's. The sweetest spot then became two units each running two jets with the magnetic"s backed off around 1.5 turns to allow the pelton wheels to run at around 850 rpm. We rewired the stators to give their output from two poles in series ( 50+ volts) then in parallel. Giving 7 by 2 poles in parallel over each of the three phases.
We tried many combinations of wiring but found the aggressive two pole variant to be the most productive even though less aggressive (2 by 7, 4 by 3 + 1 by 2) combinations were still quite good.
The newer 36 pole 48 magnet machines should work even better as you can divide the 36 poles by 2, 3, 4 or 6.
Has anyone any any experience with the newer machines.
A recent comment on the F&P's "They are an excellent machine and not too bad as a washing machine as well."

[Warpspeed]

Large hydro plants generally use Pelton (high head) or Francis (medium head) turbines however Kaplan (low head) turbines are also used.

If you want to see what a medium head Francis turbine looks like:


There are multiple control vanes to adjust the turbine speed.
Ah! you say far too complicated for a micro hydro and impossible as a home project.

But take a look at this:


Its a variable vane turbocharger exhaust turbine. Its all there, the IDENTICAL to a full sized Francis turbine rotor and housing geometry, all made of stainless steel, and they are readily available from auto graveyards.

[offgridQLD]

I looked into micro hydro at our new property. We have around 8 billion lt of water flowing through the valley each year via a permanently running creek. Though the flow is very strong the fall over several hundred meters length is only a few meters. The creeks narrow so the water flows fast (struggle to hold a open shovel against it in some sections. Though probably only good for a old water wheel style setup.

We have a hill above the creek that's around 200m elevation at the top. The elevation could be use full but getting the water up there and stored and back down again is the issue. I have a few medium sized dams on the hill that could be filled.

Would be nice if you could do something to make energy (efficiently) with the water to Air temperature differential as on a 40 C+ day the creek water temp is only 13C.

In the end the Distance from the creek to the hill and the creek to the house make the projects very expensive unless you are able to make use of the energy at the creek.

That said seeing so many tones of water weight flowing 24/7 gets your mind wondering......what if...

[davidg]

Though the flow is very strong the fall over several hundred meters length is only a few meters.

Low head micro hydro is a possible option.