Smallest MicroHydro System?

[armadillo]

Some friends of mine have a small spring on their property and potentially 80+ feet of drop. Unfortunately the spring produces less than 5 GPM. It's possible that the spring could be develloped to produce more, I dunno. I haven't done a site evaluation and know little about developing springs.
They have an excavator and are pretty mechanically inclined. I've been telling them for years they should look into this.
I've been searching the web and it seems that the smallest systems are always larger than 5 GPM. Maybe their site is just too small (in KW) for anything available at this time.
Does anyone have links to information on systems that small or links to info on developing springs?

[Harold in CR]

 Many a spring has been killed off by trying to improve production.

 My situation is, 20GPM, at 25' of head= 60 WATTS, maybe. I expect more flow during our 9 month rainy season, so, I'm going ahead with the project.

 Building a weir below the spring could store a quantity of water, and allow scheduled releases, but, I doubt there is any available power in the setup you described.

[taylorp035]

Some quick numbers:

Available power in the water/unit time = mass* gravity * height / delta time = 3.78 kg*5 gal/min * 9.8 m/s^2 * 25 meters / (60 s/ 1 min) = 77.175 Watts.

This would be 100% efficient.  So multiply this by your generator efficiency and pipe efficiency, so maybe 50% in a good set up???  This should give you a good ball park figure.

[electrondady1]

permaculture
use the 5 gpm to fill and refresh a series of fish ponds descending the 80 ft.

[armadillo]

This should give you a good ball park figure.

Thanks. About 40 watts continuous. That's barely enough to to make it worthwhile. I could live on that. They already have one on-grid home and shop on the property, so they could rob power off the grid for some loads.

[armadillo]

permaculture
use the 5 gpm to fill and refresh a series of fish ponds descending the 80 ft.

In the US, the federal government makes it very difficult and expensive to build a legal pond of any kind. The owner told me he wishes he built a pond 20 years ago when it was no big deal.

[DamonHD]

That's not to be sniffed at: 1kWh/day is the same work that you might have expected a servant or maid to do, and it's about 25% of our entire gross electricity consumption in my home.  If it's reliable, that's quite a nice source and could run (say) lighting or some refrigeration or computer gear.

Rgds

Damon

[joestue]

http://johansense.com/bulk/water_turbine_0.JPG

anyone got anything smaller to show?

i built this to run off 100 feet of head with a .125 inch nozzel.
no idea the flow rate.
i heard it still works after 6 months in ecuador.

it is designed to be wired into a 12v battery.
probably good for 2 amps or so. a 12v to 5 volt converter was included to charge cellphones.

[armadillo]

i built this to run off 100 feet of head with a .125 inch nozzel.
no idea the flow rate.

Wow! That's probably less than 2 GPM.

[hydrosun]

What kind of motor is that? Would a real pelton from spoons be a bit more efficient?
Ive run a harris hydro on a similar nozzle size and head and the amp meter barely moved. I usually rely on solar when the flow is that low on my system.
This thread started with a low output system and the question was it worth while. It depends on what other resources are available and how much you can make yourself. If you have to spend thousands for power offsetting grid power worth pennies your money would be better invested in energy conservation projects. If you are offgrid and have to produce small amounts of power it is definitely worth it. If you can cut the costs by putting it together yourself it may complement a solar system and allow a smaller battery bank.
Chris

[joestue]

It is a 3 phase motor from a copier machine.

something like 12 volts at 2000 rpm, probably good for about 2 amps or so before saturation/leakage flux takes over.

[thirteen]

Harold in CR
I read your note and am asking what you have in your system with the 20 GPM 25 ft head =est 60 watts. This is what I will have most of the time except during the spring runoff. I'll have a good supply of sun for a solar system for about 9 months out of the year. Very little in Dec and Jan. I am trying to cover the 4 months and a micro hydo will do it. If you would I would like some more information. Thanks  13

[Harold in CR]

 Hi 13.  Not exactly sure what you are asking. I will post whatever info I can for you, if you can rephrase  the question ?

[thirteen]

Hi Harold in CR 
Thanks for the reply. I am referring to your post on January 1st. I was asking what type of turbine you have with the flow of only 20 gpm and 25 ft of head = 60 watts. Is it a crossflow  or pelton type of wheel. How many spoons do you use, what are your nozzle size or is a baby stream engine but this requires more volume then 20 gpm. My system will be next year.
13

[Harold in CR]

 AHhh OK.  I am going to build a crossflow turbine, trying my best to copy the designs of the Ossberger. It actually uses the water 3 times to create the best efficiency.  Google Ossberger turbines and read the info and study the design. It's not all that difficult to build, IF one pays enough attention.  A Harris Pelton will cost me nearly $2000.00 to get shipped down here. I am going to build an axial flux alternator from this forum, to drive directly from the turbine. I would love to try ceramic bearings, but, they are costly. I have a bunch of used motor wire in excellent condition, and am using used sawblades, thicker than skil saw or table saw blades, for the turbine sides. I will measure the thickness for you, if you want me to.

 The crossflow, designed correctly, the water will strike the blades 2 times, then exit the turbine under a vacuum, pulling the water into the turbine a little better or stronger, according to other info I have read. This vacuum is referred to as "Torque tubes". My 20 GPM will be minimal amount, as in, right now and for the next 3 months. We get night time showers, occasionally, during our "dry season".

 I will pipe 4" PVC down to the turbine, from the dam. The turbine is designed with a weighted "Flapper" type water diverter, that rides right over the spinning blades, to make every bit of water that enters the turbine, strike the blades, thus, minimal splashing to speak of. There is also a second "Gate" diverter, that can move sideways, to allow more water to strike the wide blades, to , in effect, generate more power as efficiently as possible. I may not use that feature. I won't have the battery system large enough to accept a powerful charge. I want max about 250-400 Watts going to the batteries. This is a 12V, later maybe 24V system, pushing the AC V up to the rectifiers at the battery location.

 Any other info you want, just let me know. I'm nearly ready to start building the turbine, and, waiting for magnets from microwaves for the alternator.

[keithturtle]

Useful document on the Banki - Mitchell / Ossberger design and build

http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/32305/Bulletin%20No.%2025.pdf?sequence=1

Turtle

[Harold in CR]

 Excellent link. Thanks Turtleman.