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Bill Offline OP
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Phys.Org has the story. They have installed a series of turbines in a gravity fed city water supply line. The system will produce 200KW of electricity without impairing the operation of the pipeline.

This could be a good energy source for places that get their water from someplace that has a good elevation so they can get the required head pressure. Apparently it doesn't impede the flow too much so the electricity comes pretty cheap, aside from the installation and maintenance costs.

Bill Gill


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Excellent idea! I don't know why someone didn't think of it sooner. You have the water already flowing, you'd just as well use it to produce electricity along the way. Now if we could just do the same with sewage effluent, we'd have a dirty source of clean energy.


If you don't care for reality, just wait a while; another will be along shortly. --A Rose

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Quote:
I don't know why someone didn't think of it sooner.


LOL


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Quote:
someplace that has a good elevation so they can get the required head pressure.


head pressure , LOL
here's an example of a zero head pressure turbine.
too bad you can only fit 1 of these in a stream or river because
if you could fit more than 1 of these in a stream or river then that would cause the upstream water to back up tremendously , enough to completely stop the flow of water as scientist have already proven ... you must have a completely unblocked waterway in order for water or any fluid to flow because the fluid would then become elevated and then you would have a faster flow of water at the turbine and the stream and rivers would flow over their banks and the entire world would get flooded as in Noah's time ... that's why I used a extremely long level pipe to prevent the overflow of fluid as the fluid backed up and elevated at the upstream end of the pipe and this fluid elevation resulted in a proportional head pressure that acted against the thousands of water turbine's inside the extremely long level pipe ...
but only energy companies and cities are allowed to use such advanced technology ...





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Bill Offline OP
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You say that they make it so only big companies can make them. How much would it cost you to make and install a 200 KW turbine? There is a reason big companies get the contracts for that sort of thing. It takes money to make and install them. If you know any cities that wouldn't be happy to have a definitely proven system installed at low cost then let me know. Tulsa is strapped for cash and if they could save money by spending a few thousand dollars they would be happy to.

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most of your reply ...

Quote:
You say that they make it so only big companies can make them. How much would it cost you to make and install a 200 KW turbine? There is a reason big companies get the contracts for that sort of thing. It takes money to make and install them


1) a river
2) a step up transmission
3) a 200 kw generator
4) a large boat propeller

what ever that would cost.

using water supply pipes to generate electricity has been around for decades.

check out the generators inside the NY city water supply lines...

but the fact that a level pipe can accomplish the same exact result is never considered.

water inside a pipe dosn't care where its elevation comes from
so a 100 mile level pipe with a 100 ft elevation at one end still delivers 43.3 psi head pressure.

now how many 200 kw generators could you fit inside a 100 mile long pipe?

you must remember that if you put more than 1 inside the 100 mile long pipe the water will not flow thru the pipe and no electricity can be generated , as scientist have previously proven.

in fact a professor of fizzics once told me that if a level pipe is long enough you could walk inside the pipe and there would be a wall of water there that you could stick your finger into.. because the water pressure calculations that he performed told him so.. he didnt exactly say it that way but that was the mental picture that I perceived as he explained his garbage .










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Originally Posted By: paul
most of your reply ...

1) a river
2) a step up transmission
3) a 200 kw generator
4) a large boat propeller

what ever that would cost.

I notice you don't seem to have a good handle on what a 200 KW generator would cost. I don't think you can go out and build one with what you can get at the local supply store. They are expensive. They require, among other things, a lot of wire and a bunch of special castings. Very few of the things you need are things you can just conjure up out of the local scrap yard.
Originally Posted By: Paul
using water supply pipes to generate electricity has been around for decades.

check out the generators inside the NY city water supply lines...

I wasn't aware of that, but if it is a fact then good for them.

Originally Posted By: Paul
but the fact that a level pipe can accomplish the same exact result is never considered.

water inside a pipe dosn't care where its elevation comes from
so a 100 mile level pipe with a 100 ft elevation at one end still delivers 43.3 psi head pressure.

Very true, but that is all the head pressure you have and that won't drive much of a generator unless you have a huge volume of water flowing through it.

Originally Posted By: Paul
now how many 200 kw generators could you fit inside a 100 mile long pipe?

you must remember that if you put more than 1 inside the 100 mile long pipe the water will not flow thru the pipe and no electricity can be generated , as scientist have previously proven.

Actually the water would flow, but the extreme restriction would reduce the flow to such a low velocity that you wouldn't be able to get any appreciable power out of it. See my previous statement. You have to have sufficient head to provide the power you are generating.

Originally Posted By: Paul
in fact a professor of fizzics once told me that if a level pipe is long enough you could walk inside the pipe and there would be a wall of water there that you could stick your finger into.. because the water pressure calculations that he performed told him so.. he didnt exactly say it that way but that was the mental picture that I perceived as he explained his garbage .

I seriously doubt that is what he said. Unless you are counting the floor as a wall. In a pipe with no flow, which seems to be what you are talking about, water just naturally puddles on the bottom of the pipe. If you cap both ends and pour water into it of course it would be kind of like a wall, but since the wall would be behind the cap it would be kind of hard to walk into it. I'm afraid I can't take your ability to see weird pictures in your mind too seriously.

Bill Gill


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I will just reply to these points you made.

Quote:
I notice you don't seem to have a good handle on what a 200 KW generator would cost.


actually if you buy a generator head only its not that expensive , especially if you buy if from our product producers in china.

http://www.alibaba.com/product-detail/8kw-to-200kw-Brushless-ac-generator_563624432.html

1,100.00 from Alibaba , convert that 200 kw into 24/7 grid electricity @ .07 kwh and it pays for itself in a month and you have apx 9,000 to put in the bank.


Quote:
Very true, but that is all the head pressure you have and that won't drive much of a generator unless you have a huge volume of water flowing through it.


the turbine that is being acted upon by a fluid / water does not care about head pressure , it feels the pressure of the water / fluid that is moving in the pipe / penstock ...

the momentum of all of the moving water / fluid is what turns a turbine.

Quote:
but the extreme restriction would reduce the flow to such a low velocity that you wouldn't be able to get any appreciable power out of it.


if the designer of the system has designed the system to fail then it will most likely fail.
if hes good enough...

think about this , water supply pipes are around 10 ft to 20 ft in diameter , you would need to really work at stopping that flow once it had started moving , and if you tried to stop it at the end of the pipe all the momentum of the moving water would most likely explode the pipe at the end.

a 100 mile long pipe @ 10 ft diameter with water flowing inside it at a velocity of only 1 ft per second would
cause a pressure of 228,729 psi at the stopping end were you to suddenly stop the flow of water somehow.
there would be 2.5 billion pounds of water in the pipe traveling at 1 ft per second , thats 2.5 billion ft pounds / sec !!!

Quote:
I seriously doubt that is what he said.


he actually said that water would not flow at all if the pipe was long enough , even if the pipe was not capped at all .. that is when I calculated that getting opinions from people who were really good at physics was a waste of time.



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Ok, you got me there. But now let's do a little bit of engineering. How are you going to adapt this generator so it will survive when it is immersed in water? Or at the least it will be in a damp environment if you mount it externally to the pipe. Then of course you have the problem of coupling the turbine to the generator. How are you going to regulate the speed of the turbine so that it will be a constant 1500 RPM (1800 RPM for 60 Hz)? And don't forget that the turbine has to comply with regulations that are enforced to prevent contamination of potable water systems. Personally I would rather not have oil, PCBs, lead, paint and what have you in my drinking water. So you have to mount it in a sealed capsule. There shouldn't be a problem with overheating, because the water will serve as a good coolant.

Originally Posted By: Paul
the turbine that is being acted upon by a fluid / water does not care about head pressure , it feels the pressure of the water / fluid that is moving in the pipe / penstock

Right, and of course the movement of the water depends on the head pressure. With a zero head pressure, represented by your example of the perfectly level pipe, there is no flow. The greater the pressure difference between the entry to the pipe and the exit from the pipe the greater the flow rate, and the more power there is available.

Originally Posted By: Paul
think about this , water supply pipes are around 10 ft to 20 ft in diameter , you would need to really work at stopping that flow once it had started moving , and if you tried to stop it at the end of the pipe all the momentum of the moving water would most likely explode the pipe at the end.

Right, and that is why when you get it started moving you don't try to stop it by closing a valve at the outlet end. You close it with a valve at the inlet end. In homes this is what causes knocking in your pipes when you cut off the water suddenly. Normally the pressure and flow rate are low enough so there isn't any problem, but sometimes there is. Of course if you put turbines in a pipe they won't cut off the water suddenly. They just slow the rate.

Originally Posted By: Paul
he actually said that water would not flow at all if the pipe was long enough , even if the pipe was not capped at all .. that is when I calculated that getting opinions from people who were really good at physics was a waste of time.

And I suspect that you are taking his statements way out of context. There won't be any flow through a perfectly level 100 mile pipeline if the water level of the source is not higher than the water level of the sink.

So I guess that is enough for viewers to realize that you really don't have any idea what you are talking about so I guess this discussion is closed.

Bill Gill


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Quote:
Right, and of course the movement of the water depends on the head pressure. With a zero head pressure, represented by your example of the perfectly level pipe, there is no flow. The greater the pressure difference between the entry to the pipe and the exit from the pipe the greater the flow rate, and the more power there is available.


Now your sounding like the nutty professor did ...

my example is 100 miles but it has a 100 ft water head elevation at one end.

that 100 ft elevation = 43.3 psi pressure

that 43.3 psi pressure is also present at the 100 mile
end of the pipe if the pipe is capped.

Quote:
And I suspect that you are taking his statements way out of context. There won't be any flow through a perfectly level 100 mile pipeline if the water level of the source is not higher than the water level of the sink.


I suppose your thinking that the end of the pipe has a upturned elbow attached to it , but it doesnt , its open.
is this where I pictured myself walking up the 10 ft diameter
water pipe to the point where the water could flow no further and saw the wall of water just standing there and so I put
my finger into it?

no one has said exactly where the point would be where the water would no longer flow inside the level pipe , perhaps I should hire a taxi for the trip?

also , would you please stop acting like you have solved an issue by dictating the end of the discussion when the end is no where in sight.

I'm going to say that I dont think you are stupid.
I actually think you are a pretty smart fellow.

Please dont make me feel as if I have you figured wrongly ..

I'm certain that you can agree that a 100 mile long
10 ft diameter pipe that has a 100 ft tall upturn at one end and a open at the other end would allow for water to flow through it.

and

if a ample supply of water is fed into the upturn end of the pipe then the 100 mile long pipe would not present enough resistance to fluid flow inside the pipe to completely block the flow of water and even if the pipe were to become completely filled with flowing water the 10 foot diameter pipes resistance to flow would not ever in your wildest dreams be capable of stopping the flow of water or even lessening the flow no more than 10 - 20 percent of the area of the cross section of the pipe.

and

if turbines were placed inside the 100 mile long pipe they would also not stop the flow of water through the pipe , even if you placed a turbine evey 10 feet inside the 100 mile long pipe (52,800 turbines), they would only slow the flow of water through the pipe.

after all if the 100 mile long pipe and the 100 ft tall upturn were filled with gravel and water were fed into the upturn the water would still have little problem finding its way through the 100 mile long pipe and exit the pipe.

your not stupid.

BTW if the 10 ft diameter pipe is determined to reduce the flow rate too much , then FR = AV settles the issue , just use a bigger pipe and voila problem solved !!!


flow rate = area x velocity















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