# hydro turbine 100 kw

7 Posts
May 23, 2006 04:35 am
hydro turbine 100 kw

i wish to run a turbine 100 kw off a approx 30m wide river with out bloking the whole river. also dont want to use batterys .the problem seems to be there is almost no head on the river .Q could someone advise me on how to calculate the volume of water to run turbine. thx

351 Posts
May 25, 2006 12:34 pm
Re: hydro turbine 100 kw

to calculate the volumn of water in a river as large as yours, you will need to you will need to measure the depth of the river to establish a bottom profile/ cross sectional area. Then by measuring the current speed, you can calculate the total volume per second. Here is the location of a .PDF file that will tell you how to do it.

Meanwhile, from your brief description, it is highly unlikely that you will be able to get anything close to 100kw from this source. Is that a real number or something that you just would like to have ?

7 Posts
May 26, 2006 12:53 am
Re: hydro turbine 100 kw

um yes thank u.for ur reply gratefull thank you. i cant get or dont know how to use
pdl on my computer is some thing needed to download?. any way yes i do need 100 kw electric kiln heaters powder coating oven and house hold.
river has not much head but quit amount of flow.
i was thinking a wider wheel perhaps for more torque.but then maybe just a way bigger wheel like 8 feet with a lot of torque and then just gear it to run turbine. ive got the volume i think
thanks for ur imput. yours tum.

351 Posts
May 26, 2006 12:49 pm
Re: hydro turbine 100 kw

LAST EDITED ON May-26-06 AT 01:54 PM (EST)

Water wheels are better for mechanical work than generating electricty. Gearing the wheel speed up to generator speed eats a lot of power.
You may want to visit
http://www.waterwheelfactory.com/

According to their numbers a water wheel 12 feet in diameter with 6.68 cu ft a second (3000 gals/min) generates about 7.7 hp.
With the gearing losses, that would generate something around 3kw.

7 Posts
May 27, 2006 12:20 am
Re: hydro turbine 100 kw

to oso having trouble with calcs. ive worked out that the cross section of  the lowest point of
river is 2 ft deep x 30 ft wide. and has a flow
of 5ft a second.do u think thats suffisant,to generate 100kw.thank you.

351 Posts
May 27, 2006 11:54 am
Re: hydro turbine 100 kw

LAST EDITED ON May-27-06 AT 11:55 AM (EST)

"the cross section of the lowest point of
river is 2 ft deep x 30 ft wide. and has a flow
of 5ft a second."

I am not sure whether that means that the deepest point in the 30 feet is 2 feet deep, or whether you mean that it averages 2 feet deep for the 30 foot width.

If it averages 2 feet deep, that would be a flow of 300 cu feet a second. If 2 feet is just the deepest point, and it shallows rapidly, you may only have 100 cu feet a sec.  But the good news is that a river that size should have a stream guage on it. If you would give me the name of the river and the name of a town nearby (and state), I can look for stream guage data on it.

Another question for you. In rereading your need for the 100kw, I think you have taken the total of all loads and sized your generator based on that. I am thinking that you may get by with something smaller, which would cut down on the cost.  Do you have a current electric bill for this property, or is this something in the planning stage ? If you have a electric bill, What is the total killowatt hours billed per month ?

7 Posts
May 27, 2006 08:04 pm
Re: hydro turbine 100 kw

yes the average depth of the river is 2 feet x 20 ft wide.yes it is in its planning stage and no electricity is on property. idont know if u can find gauge in another country ,any way its weka weka river in weka weka far north northland which is about 280 km north of auckland in new zealand.also the slowest flow of the river could be as slow as 2.5 ft per second.
not sure exactly how much power i need .basicly
powder coating oven approx 24 cubic metres a brick kiln approx 7 cubic metres lighting power for a three bdrm house and lighting power for a 30x15 meter shed with verious other type three phase machines.basicly working on a average sized factory around auckland which seems to be on average around 100 kw.
hope i havnt left anything out .thx very much for all your work.appreciate it very much thank you. tum.

351 Posts
May 29, 2006 12:12 pm
Re: hydro turbine 100 kw

You are probably at a point where you should get someone local (either a hydro engineer or an alternative energy specialist) to take a look at your problem.

I think it is very doubtful that you will be able to produce anything near 100kw. But that is a remote judgement based solely on verbal descriptions. Someone local could take a look at the site and might come up with another opinion.

The other thing the local person could do is to help you refine your power requirement. 100kw is a ton of power. Your actual need could be much less.  "basicly working on a average sized factory around auckland which seems to be on average around 100 kw" could have you looking for something that may be twice the size of your actual needs.

7 Posts
Jun 1, 2006 03:16 am
Re: hydro turbine 100 kw

thx again for advise will work towards seeking a professionals apinnion. couple of years away yet tho still working on shed.how would u think getting the most out of a river ;dambing or mill race ,is it pressure or flow when theres not much fall. thx

462 Posts
Jun 8, 2006 01:13 pm
Re: hydro turbine 100 kw

Tum,if your property runs along the river, you could consider running a pipe from somewhere upstream down to where you are in order to gain some head pressure...

7 Posts
Jun 9, 2006 10:01 pm
Re: hydro turbine 100 kw

yes i wondered about that.does the lenght of pipe contribute to pressure or is totally the head.

Jun 22, 2006 07:53 pm
Re: hydro turbine 100 kw

Just a thought. Maybe someone could elaborate on this?
It would take less electrical energy to power an electrolizer to produce hydrogen which could then be burned in order to produce the Btu's needed for the kiln and oven. I am geussing that the kiln might run day and night but that the oven would not. As for the home... go solar with water genny as back up and burn hydrogen or reclaim heat from kiln and or oven for; heat, cooking, water heater, lighting, refrigeration, whatever LPG or NG can do hydrogen can do.
Maybe this is all a little to futuristic. I mean its not like we can go down to our local home improvement store and buy it off the shelf now can we? Shhuh, cant even do that with any of the RE mediums. I geuss its just as well they havent gotten ahold on them yet. I can see it now... a \$300 PV module that sells for \$450 now because of this so called shortage of raw materials, would sky rocket to 700 bucks if sold at every home improvement store but not just PV.

7 Posts
Jun 23, 2006 01:55 am
Re: hydro turbine 100 kw

yes could some one elaberate on that. whats a electrolizer,? sounds interesting to be able to produce hydrogen from water?and what would the set up cost be .maybe cheaper than turbine or large turbine, interesting thx for imput more imformation please.

462 Posts
Jun 30, 2006 04:45 pm
Re: hydro turbine 100 kw

the length of the pipe effects the pressure due to friction losses. The over height from one end to the other gives you your head pressure. Head pressure minus the friction losses gives you the total pressure.

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