small microhydro generator

[goingoffgrid]

Hey guys, been working on my micro hydro system. I've got 35 feet of head going through 4" schedule 40 black pipe. Distance about 350'. I'm currently getting 150 gpm. Min I've seen about 30 (but pretty rare). I was considering using 2 laundry pumps (centrifugal) run in reverse. They have 1 1/4 inlets, so based on the volume I would use one or both. I have a condor 800 watt 120v dc pm wind generator i was going to attach to the one, and considering a 500 watt 24v dc pm generator from Electrovent for the other. Anyone have any experience, thoughts or comments would be appreciated.Thanks

[Coles]

Using pumps as turbines?  Here's a good read.

I reckon you'll lose 10-12% of your head due to friction, and if you could achieve 50-70% efficiency you'll produce between 510-720watts.

[David HK]

The following website provides some interesting articles on water motors of various types.

http://www.aqpl43.dsl.pipex.com/MUSEUM/POWER/watermotor/watermotor.htm

David in HK

[goingoffgrid]

Thanks guys, checked out those sites,good info. Will persue this some more. Will also send out pics once i get more of the system in place.

[Basil]

Sounds close to what I have. Just a bit more. I have only 21 to 22 feet of head.
100 foot run is all I will run to get it. No way to get more. I also have
around 120 GPM. More some times. My project is slow going so I will be watching to see
how you come out. Keep us up to date. Don't forget photos.

[hydrosun]

I've been watching this thread for the last few days, waiting for someone with experience with pumps as turbines (PAT) to comment.  As I understand PAT is that they drop off in efficiency very rapidly when not used at full flow. They are usually used in cases where the cost of the large purpose built turbines would be very expensive. They are not as efficient as turgo or pelton turbines even at full flow. In your case with 150 gpm and 35 feet head a small turgo with multiple nozzles would be a more efficient option to get the most power out of your site. A good turbine should put out about 500 watts at full flow and still be efficient at partial flow by using varied number of nozzles.
 As far as using the  PM motors you need to see what rpm they produce the voltage of your system to see if they would be a good fit. At your head a 4 inch pelton would be turning at about 1000 rpm. I don't know the effective diameter of the pumps you are proposing to use to give you an idea of the motor speed you would need. 
Or you can just put the systems together and see what the output turns out to be if you just want to experiment.
Chris

[bj]

   Had a bit of experience with pumps as turbines at a chemical plant I worked at.  These were direct connected to an electric motor, with the idea
being it would take some of the load off the motor.  They were more or less fixed head, and of course fixed rpm.  Flow varied approx. 30%.
   These were a standard pump volute, but had what was called a "mirror image" impeller.  It wasn't exactly a mirror image, but you get the idea.
    Anyway, they were very effective, and the  flow increases simply created more power.  If memory serves, they were Goulds, and they impellers
were an off the shelf item.  These were too large for most hydro, but some manufacturers may stock the impellers in smaller sizes.  With access to
a lathe, and welder, one could be built for lower rpms.
  Just to let you know it is done commercially.