Micro-Hydro site - need advice on best turbine.

[ecogeorge]

I have a friend who has a stream. Flow is constant with a possible head of 10 feet. Flow today (normal weather- not in flood )  was measured at approx 500 litres  minute-  Well we inserted a piece of drain pipe into the stream and caught the water. A 15 litre bucket filled in 5 seconds and this was only about 1/3 of the stream flow. This sream flows within 6 feet of his house !! During the summer  flow could be down to an estimated 150 litres / minute.

What type/size / make of turbine would you fit here?

I thought something like a stream engine but these are expensive in the UK. How would he use the power generated from it ? House has a reliable grid connection so battery charging seems pointless!

Any thoughts / ideas out there folks? apart from letting me have the stream to experiment with.

thanks in advance

George.

[Nando]

Well, you have good info.

10. feet = 3 meters
    
5. liter/sec with 1/3 stream, is that the maximum you can use or can you use all ?.
   
150. l/minute = 2.5 l/sec
     
     

The power per liter/sec will be:

3 meter * 6 = 18 watts for each liter/second available

Since he has GRID power, the idea would be to have a small turgo turbine driving a induction motor at higher RPM than the slip and connect it to the GRID for energy credit ( so small that nobody will notice it but will "reduce" the expenses in electrical energy).

Ideally get a 4 poles small induction motor 1/3 or 1/2 HP SIZE

A Turgo, from www.h-hydro.com may be adaptable, though the head of meters is low --

I have 2 friends doing exactly that, one produces about 200 watts and the other 500 to 800 watts -- Guerrilla Energy Fighters --.

The good thing is that if the grid goes dead the generator goes dead and disconnects and the 500 watts unit gets immediate connection to a capacitor to produce local energy.

Nando

[ecogeorge]

Thanks for the reply Nando. I like the idea of turgo/motor combination it sounds simple but effective.

I am familiar with Guerrilla energy (I have 1200w grid connect solar that turns the meter backwards during high sun ,low load ) .

I am probably capable of obtaining motor and turgo but how do you connect to grid?

How do you measure power produced ? does the motor need coaxing to produce power?

More info gratefully received.

I am not an electronics expert but can cope with simple circuits, domestic house wiring , motor start circuits up to say 5kw single or 3 phase.

regards George.

[Nando]

The Turgo turbine needs to be calculated, diameter wise, to define the operating RPM to be higher than the motor RPM + Slip, and once there a switch to trigger a Zero Crossing Triac to place the motor to the GRID, which will give the bias to the motor to behave as a generator.

So you may need a RPM counter to detect RPM+Slip and as well to detector lower RPM to disconnect from the GRID.

A simple Breaker in series will do the protection and a current transformer will do the "display" the Guerrilla Generated Power.

Also, one could add more circuit to show how the power and its phase is going into the GRID.

RPM detector would be a pulse counter, like placing a small magnet on the Shaft of the motor to trigger the Zero Crossing Triac to engage the motor to the GRID, the RPM circuit should be isolated from the Triac, which is a low cost unit with a small heat sink.

Does this help ??

Nando

[Vtbsr]

Hi George, The way to hook it up is to connect just like if you wanted to run any motor. The grid will spin the motor at the rpm on the name plate. You have to spin it faster than the run speed to get the power to pump back to the grid. This will match the 50 or 60 cycles of the grid. I have heard of a system like this, where the penstock was pluged up and the generator ran as a motor for a few days.You might be able to have a red light and a green light on the turbine house to make sure the power is flowing back to the grid.

[Ungrounded Lightning Rod]

You can run the motor through a regular electric meter to measure power.  I got a reconditioned one (of an older model) from my local utility at the time (Detroit Edison) for just a few bucks.

Told 'em I wanted to check the power draw of some appliances (which is what I've used it for ever since - nice to know what the appliances are eating.)

They sell recalibrated used mechanical meters to private citizens and appliance shops all the time.  Cheaper than dumping them, even back then before the enviromental regs.

I like the old Tesla/Westinghouse designs rather than semiconductors because they're cheap, solid as a tank, and tell you exactly what the power company things the power draw is even if there are issues with waveform, power factor, and/or DC bias.

[asheets]

semi-detailed instructions:

http://www.utterpower.com/playing.htm

[Phil Timmons]

If you are going to grid tie this rig -- whether guerilla or under agreement, it needs to be done safely, else you could toast a power company lineman or a neighbor.  Not a nice thing to do.

Both the cyclic rate and the voltage need to be monitored and protective "drop-out" relays are required to ensure that the system does not send power up line if the grid were to drop out.  

We covered most of this, including some UL listed monitoring hardware here:

"Induction Generators and Grid Tie controls" >>>

http://www.fieldlines.com/story/2005/3/16/183628/827

As per Dr. Suess:  We play.  We play all day.  But play safe.

[ecogeorge]

Thanks everyone to your comments and ideas.Being a friends stream and not mine all solutions MUST be user friendly and reliable. I am hooked on the idea of grid tie motors but will probably cop out and use a low voltage (12-24v) dc generator and grid tie using a OK4E or a mastervolt 500 -this I beleive will be UK compliant later in the year.What I do I will keep the post informed.

Regards ecogeorge.