manifold before generator

[strider3700]

Ok a few months back  I asked about how much power I can get from my spring that supplies my water line in this thread

http://www.fieldlines.com/story/2005/6/24/43128/1069

Anyways I've been figured some of the details out  so changes are

• It's 1.5" line running from the spring to my house.(sorry it's 500 feet away and buried 2 feet down  I'm now adding bigger)
  
• I'm the only person on that spring so if I suck it dry thats my problem and no one elses
  
• I have legal water rights to the spring so I can do as I please with it (drinking/watering is implied but power generation isn't outlawed explicitly )
  
  

So as soon as I knew that I could use it for power I was stopped because I'm busy building a new shop to house my water system.  This shop will house the future generator.

My questions -

I'm going to build a manifold to direct the water once it comes into the shop,  basically a lot of T's that will be closed the vast magority of the time,  one to the outside taps, one to the water tank, one directly to the house... The most important is one will go to the generator and will be left open a good chunk of the year.  Now since the water line coming in is 1.5"  should I stay that size or should I go with 2" which is probably easier to locate.   This would only be for the manifold  so maybe 4 feet's worth at best.  

Also when I send the water to the generator what should I be doing with it.   I can add some form of nozzel to make a jet  or I can simply let it gush out.  I'm assuming which way I go depends on the wheel I choose to build?

also  The water is coming in from a 1.5" pipe under pressure.   I'm assuming that to stop the box that the water goes into from filling up after it goes through the generator I'll need larger to make sure that it gets out quick enough?

Thanks for any info

[Flux]

No need to go bigger, but if 2" is easier to get then it will be ok.

Keep the line to the turbine straight through except for the valve. Tee the others off the side. Dont make a right angled manifold.

You need a suitable nozzle to suit your chosen turbine, you can't let it gush out, you need to increase the water velocity.

Yes you will need a big drain hole, water at low pressure will need a hole much bigger than 1.5".

Sensible options are a Pelton, Turgo or a Banki if you want to build it yourself.

There are a few people selling small turgo rotors.

Don't consider water wheels with that set up.

Flux

[strider3700]

Thanks

I've been thinking about building a banki  but I don't see it as needing to form a jet does it?  I've got a solid 1.5" or 2" round column of water coming out at 50 psi.  This would go into a nozzle to make a jet of water for a pelton wheel just fine but for a banki don't I want the water flattened out into more like a stream to hit the turbine in a wider area?  or should I be looking to build a turbine that is just 2" wide?   I've seen info on building the banki  but nothing dictating how wide the unit should be given a set amount of water coming in.  

[Flux]

Although a Banki is a mixed flow turbine, the first stage which extracts about 75% of the power is impulse just like a pelton. You need a nozzle to give you the maximum velocity.

You may have a static head of 50 psi, but the water emerges at atmospheric pressure. You need a nozzle to increase the velocity for you to extract the momentum. You should find that with the optimum size of nozzle the pressure measured at the back of the nozzle is about 2/3 of the static head ( 33 psi).

Your nozzle height can be roughly the distance between blades and it will probably not be much wider than the supply pipe. I doubt that you will need a runner more than 3" wide and it may well be less. The shape and position of the nozzle is fairly critical to get the water to emerge from the blades at the correct point for the second stage. There is information available on the net but as always it is not all accurate, but with the basics I have given you should be able to find reasonable design details for the size and position of the blades, rotor diameter and blade spacing.

Flux

[Vtbsr]

I would go with a pelton 4 nozzel. With the 4 you can vary the flow much greater so you won't drain the spring. You can run as much as the spring will produce. Check out the Harris hydro. It has a varable field strength knob if your flow or power changes. If you tried a cross flow the width would be less than 1 inch. You need the rectangle nozzel or the crossflow wont work. You dont have the flow for a crossflow but have the head for a pelton. With the Harris you can also fit different dia.( 3/8 to 1/8) nozzels to vary the flow in the 4 entry pipes. The one problem you may face is the 1 1/2 inch penstock may reduce the head or presure to much to get much power.

[strider3700]

A pelton seems to be more difficult to build and balance then a banki.   Why go with the 4 nozzels?  I don't have that much flow.