Author Topic: Long distance hydro  (Read 1849 times)

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chipbb

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Long distance hydro
« on: February 25, 2005, 02:28:36 PM »
Hello,

I have a potential site for hydro power near my proposed house site but with at least one potential problem,, its a long ways away. The flow rate is roughly 100 GPM,, the point at which the wheel should be located has roughly 40' of head ( most of which happens in the last 300'-400' of stream ),,,, but this site is roughly 1700' from the house. Will the line loss be to great? What other limiting factors may exist?

Thanks,

Chip

Moultonboro, NH
« Last Edit: February 25, 2005, 02:28:36 PM by (unknown) »

wooferhound

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Re: Long distance hydro
« Reply #1 on: February 25, 2005, 12:04:40 PM »
« Last Edit: February 25, 2005, 12:04:40 PM by wooferhound »

jimovonz

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Re: Long distance hydro
« Reply #2 on: February 25, 2005, 12:11:09 PM »
I'm just in the process of putting in a pelton turbine myself. I was faced with the same problem of transmission distance only I have less power (~200W) and further to go (~2000ft). Going by your figures you will have somewhere in the region of 350-400w of electricity avilable at the alternator. The amounts to approx 9kWh/day and is easily enough to power a house if your efficient in your use. The transmission line loss will be decided by the size of the cable you run and is easy enough to work out. Obviously larger cable costs more so its a trade off. Depending on your alt, you could transmit the power as rectified DC using 2 conductors or AC (3 phase?) using 2/3/4 conductors depending on how many phases your alt uses. One possible benefit of transmitting the power as AC is the ability to use transformers. You could configure your alt to put out high voltage and thus reduce your transmission losses and step the voltage down at the point of use. This was what I planned to do, but I decided that I would get better value out of using the pelton wheel to direct drive a water pump to supply water to the house. I have mounted the pelton cupss directly to the pump shaft and have set up the whole unit in a plastic drum. I use the stream power to pump water from an adjacent sspring. This system is much more efficient than producing electricity to do the job and should deliver ~1300gal/day to a 650ft head.

Your setup sounds perfectly 'doable' and I'm sure the cost of the transmission line will be more than offset by the fact that the system should produce most (if not all) of your power.
« Last Edit: February 25, 2005, 12:11:09 PM by jimovonz »

Nando

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Re: Long distance hydro
« Reply #3 on: February 25, 2005, 01:50:36 PM »
Chip:


your values indicates around 450 watts, expect around 300-370 watts.


A Small Banki may be the best choice for you driving an Induction Motor as generator producing 240 AC volts, frequency any, from 50 to 400 Hertz, for low transmission losses and at the load a transformer bringing the rectified voltage down to to a C40 charger controller range ~ about 20-30 volts above the battery voltage.


Also once the battery bank is charged you may use the power for water heating, or even used directly ( converted to 120 )


With 300 watts you may have 7.2 KWh per day (24 hours).


We have installed small 800-1500 watts systems sometimes at 3000 or more feet away from the load ( 240 AC transmission ) and most of the time no chargers but direct AC use (transformed down to 120 Volts AC) no problem since the early 1980's


Regards


Nando

« Last Edit: February 25, 2005, 01:50:36 PM by Nando »

chipbb

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Re: Long distance hydro
« Reply #4 on: February 25, 2005, 07:27:43 PM »
Thanks,,  very helpfull.

I have since remeasured the distance and found it to be closer to 3000' but it sounds like its still doable.

Thanks again

Chip
« Last Edit: February 25, 2005, 07:27:43 PM by chipbb »

LEXX

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Re: Long distance hydro
« Reply #5 on: February 25, 2005, 07:32:21 PM »
Nando, very good idea for limiting line loss, it wouldn't work for wind gennys but for a year-round flow of water it should work very well.  Not quite sure why i never thought up that one, pretty much an industry standard!!  

LEXX
« Last Edit: February 25, 2005, 07:32:21 PM by LEXX »

hydrosun

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Re: Long distance hydro
« Reply #6 on: February 26, 2005, 11:27:17 AM »
Home Power did an article on using induction motors as hydro generators.  The efficiency was very low (under 30%).  Apparently they  work very well in ac direct systems like Nando describes, but it is harder to set up an efficient system when the power is rectified to charge batteries.

As an alternative I've set up two systems with Harris hydro units putting out higher voltage dc. At the battery I'm using an Outback Mx-60 to drop the voltage. The trick is to keep the voltage from going over the 140 volts maximum that the Mx-60 can handle. It needs a voltage clamp on the input to hold down the voltage  when the Mx-60 goes open circuit to set it's maximum power point.

What I've used is solar panels hook up in parallel with the hydro.  They  act like zener diodes to keep the voltage from going  too high.  For example one system has solar panels with a combined rated open circuit voltage of 120  volts and the hydro input pushed the voltage to 140 volts and now runs at the mpp of 115 volts. The added benefit is the MX-60 will mppt the solar panels when the hydro dries up in the summer and the solar needs to put out the most. I found out first hand what would happen without the solar panels.  I was changing the panels one day without shutting down the hydro and the Mx-60 fried.   (On my own system running at 60 volts and charging a 24 volt battery I ran for one season by starting the hydro at low output untill the Mx-60 started and then putting on full. As long it never went open circuit it worked fine. But the most my hydro would do was 146 volts, enough to shut off the Mx-60 but not fry it. I now have solar panels on my system and it prevents any problem.) The input capacitors  of the MX-60 can't handle the voltage spikes  over 150 volts. Outback repaired it but said they couldn't warrantee anything beyond their equipment. They are working on a voltage clamping circuit to be able to use the Mx-60 with wind generators but it hasn't been released yet. No-one can tell me if any possible damage can be done to the solar panels. To mimalize the possibility I'd use solar panels with at least 1/2 the output of the hydro.

Or go out and find huge zener diodes. Or zeners to control transistors to turn on resistor loads.  I think the solar panels as zeners is a much more elegant solution to be able to use the Mx-60 as a dc-dc converter in hydro and keep the efficiency in the 60 -70% range. There is someone in Hawaii using panels with a 48 volt hydro but I think I'm the only one who has pushed the voltage over 100 volts. So it should still be considered experimental. But it has been working fine. I also previously replaced the stock Harris rectifier with a heavier, higher voltage bridge rectifier and capaicitor to handle over 100 volts. Good luck, Chris
« Last Edit: February 26, 2005, 11:27:17 AM by hydrosun »