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 2
Head (meters) x Flow (litres per second) x Density (kg/litre, usually 1.0 or close) x 9.81 (m/s/s) = Power (kgm^2/s^3, or Watts)
1 W = 0.00134102209 bhp.
Let's start with an assumption. You want to make 60 horsepower by collecting rainwater. I am thinking this is where your invention is heading since you said it could be used anywhere and hadn't been patented yet. (this actually has been patented but never used for reasons you are about to see)
Head is the fall of the water, in this case the length of the lever arm of the waterwheel. Let's say your lever arm is pretty big, like 10m.
Flow is based on area of the bucket and the rainfall. Let's assume we're in the PNW and it rains 1cm in a day.
Density is given at 1.0 kg/l.
Now solve: 60 bhp = 44,742 W = 10m x 1kg/l x 9.81 m/s/s x (1cm/day /24hrs/day / 3600 s/hour x A(cm^2) / 1000 (cm^3/l))
Punch the numbers, A = 3.91 x 10^10 cm^2 = 3,916,624 square meters = 968 ACRES.
Of course, if the bucket is this large, then obviously the lever has to be bigger!
Recalculate: 968 acre bucket with a 10m lever makes no sense. Let's go with a waterwheel a kilometer high!
44,742W = 1000m x 1kg/l x 9.81 m/s/s x (1cm/day/24 hours/day/3600s/hous x A(cm^2) / 1000(cm^3/l))
A = 39,405 square meters.
Much better. So the final dimensions of the rainharvesting waterwheel: 1000m high, with a series of buckets 100m wide and 400m long.
Humor aside, you can use the formula above to calculate dimensions of most any overshot waterwheel, or any waterpowered device that does not have significant kinetic energy to harvest. If a waterpowered device USES kinetic energy, such as a Pelton wheel, the calculations are different.
If you would care to share the fundamental properties of your invention, though, I would be happy to help you with the calculations.
The number of buckets does not matter. Only the lever arm and the volume/time of water.
Using the above calculations, if the water wheel is 2m high, the required flow rate to make 60 horsepower is 2,280 liters per second, or 602 gallons/second. (assuming 100% efficiency, of course, I neglected efficiency in the initial calculation because I didn't want to be TOO obnoxious)
Keep in mind that 60 hp is a lot of power. That's 44,742 W, or 392 Megawatt hours / year, enough to power roughly 80 efficient homes.
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Mac abees wrote:ok i know if the water wheel turns slow enough a pump can fill the buckets on the wheel and the generator will run the pump but it has to be worked out just right so it will sustain its self. Ive heard it cant be done but i just makes so much sense to me that i wont let up until i figure it out . im tired of paying $250.00 dollars a month to the electric company every month.
Okay, that was what I thought.
In my experience when someone is "thinking outside the box" for power systems what they are really saying is "I don't understand or choose to ignore the basic laws of physics".
The internet is full of crackpot ideas that will never work. This one lands squarely in the crackpot "perpetual motion" or "overunity" category.
I just saved you a lot of money from now having to make such a flawed device or trying to patent it. It is unpatentable anyway.
and i will be taking it in big bills please.
Come on Dave obviously your smart and it can be figured out on how big a wheel i need that isnt gigantic. This is the only thing i need to get this going. asuming i got more than enough water to supply it. If you can help me with that you can keep your Trillion lol.
Even a Pelton making 44 kilowatts is going to be as big as a car.
Mac abees wrote:Wow thats exactly what i was looking for 3 rpm is all that wheel turns nice! So a 24 ft tall wheel, @ 2 ft wide or a 12 ft wheel @ 6 ft wide is where my calculations are taking me, Thanks again john.
I dont think the maths are that simple as your wheel size has a lever effect. Thats why I quoted keeping the wheel size constant.
http://www.waterwheelfactory.com/hptable.htm
If you get stuck I am sure they would help you.
but from i gathered youre working on a water wheel of your own deisgn in which case, even without knowing the math behind it i am all for you experimenting until you got it figured out how you want, be sure to keep up updated (hopefully with pics) when the prototype is doen and how the progress is going and all that, even if you dont figure it out, leaving the knowledge somewhere it can be found easily by others could still result in some large improvements to current designs and such
Do you know the M.C. Escher work "Waterfall?" I was thinking of something like that, but with a wicking system up the zigzag lift, and an air and water powered pump from the bottom of the system to the top via the tower, which would be a big adobe watertower with a WOFATIstyle structure and roof, if possible. And friction turbines against the mill wheel could operate hydraulic pumps to recoup braking losses when the millwheel isn't engaged.
Mine would be art, air humidification, and, mindfuckery, mostly, but not practical purpose. I am positive that there would be no net gain of energy beyond what would be harvested by solar and wind inputs.
CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
Robert A. Heinlein
Apologies to those who already know this:
By expending that energy you increase the potential energy (due to gravity) of the water you lift, minus the losses in the pumping process. You cannot, by normal physicalchemical means, create or destroy energy, you just convert it: so you change kinetic energy in flowing water or wind into electrical energy, then you convert that to "chemical energy"* in a battery and later you convert that back to electrical energy and then convert THAT into heat, light, kinetic etc. energy. And, at every stage, you lose some of the energy due to inefficiency. Ideally, you'd convert the kinetic energy of the river or wind directly to kinetic energy to do the work you wanted done, as in a water mill or windmill.
like yourself to find the opportunities that those more conventional of us will miss because we are busy explaining why wehavealwaysdoneit thisway !
Having said that, please take the time to reread this whole Thread, Finding an alternator that will run at the R.P.M. you can supply will be easier than building an entire
specific system to match your Alternator/Generators speed, Its more important to match your alternator to your storage capabilities !
The more information you can share the more help we can give you ! You may want to scan the other Forum Threads in the Hydro section And contact a few members,
Like they say at "American Express'' membership has its privileges !
For the Good of the Craft! Be safe, keep warm ! As always, your comments and questions are solicited and are welcome ! PYRO  LOGICally Big AL !
Success has a Thousand Fathers , Failure is an Orphan
LOOK AT THE " SIMILAR THREADS " BELOW !
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often find a familiar group with widely different view points, who want to talk about wait you want to talk about. Hopefully, you will be continually blest with a well turned phrase that
unites different views ! For the Good Of The Craft ! As always comments / questions are Solicited and Welcome ! Think like Fire ! flow like a Gas ! PYRO  Logically BIG AL !
Success has a Thousand Fathers , Failure is an Orphan
LOOK AT THE " SIMILAR THREADS " BELOW !
Mac abees wrote:Ok here goes! I need to build an over shot water wheel, head does not matter, speed does not matter. All i need to figure out is how big, wide and deep a wheel I need to get at least 70 to 80 horse power at the shaft if some one can help me with that i can build a generator system anywhere. I will explain the rest after my patent lol. Eveyone one seems to be hooked on speed or rpms thats not what you need. The wheel should be at a snails pace but geared to spin a generator at 3600 rpm. Its right here in my head but to actually work it out in the real world i need help at this point the rest is easy. Im using just the pure natural weight of the water to turn the wheel.
5 Dia Wheel Wire spool
2.5 Radius
5 mph Stream
50 pounds of force on the wheel is not too unimaginable
15.707963267948966192313216916398 circumference
Since 5280 feet = 1 mile
5280/15.707963267948966192313216916398=336.13523981008294914388250824274=
1680.6761990504147457194125412137 RPH
28.011269984173579095323542353562 RPM
5.6022539968347158190647084707123 RPM = a 5 foot Dia wheel needs to turn about 5 RPM to reach 1 mph
28.011269984173579095323542353562 RPM to reach 5 Mile an Hour
125 pounds of torque = 50 x 2.5R
70 to 6 teeth 1:11.666666666666666666666666666667 (Bicycle Cog to Lawn mower sprocket)
28.011269984173579095323542353562 x 11= 308.12396982590937004855896588918
308.12396982590937004855896588918 RPM (Too low RPM)
70 to 6 teeth 1:11.666666666666666666666666666667 (Bicycle Cog to Lawn mower sprocket) again
3389.363668085003070534148624781 RPM
5.6818181818181818181818181818182 Pounds of torque If Torque is some what Hp relative, then
5 hp Minus the deficiencies of the RPM multiplier(s)
About 4,000 Watts
However, 3600 RPM is not needed (For 60cps) if a Car Alternator is used
Suggest; 800 RPM Field dependent (Stator) Low RPM is more efficient and less Cost
Also consider;
Alternator uses a electro magnetic field which is voltage variable = variable wattage output
Generator uses a perm magnetic field which is not variable = Wattage output is RPM dependent
Smaller the Wheel is the faster it will turn
Power (or wattage) is developed by Torque
When generating AC Power the only thing to consider in RPM is Cycles per second.
To get 60 CPS Most small AC Generators require 1800rpm and Lighter portables are 3600rpm
To get 80 hp my figures can be extrapolated
Phil Bannon wrote:
Mac abees wrote:Ok here goes! I need to build an over shot water wheel, head does not matter, speed does not matter. All i need to figure out is how big, wide and deep a wheel I need to get at least 70 to 80 horse power at the shaft if some one can help me with that i can build a generator system anywhere. I will explain the rest after my patent lol. Eveyone one seems to be hooked on speed or rpms thats not what you need. The wheel should be at a snails pace but geared to spin a generator at 3600 rpm. Its right here in my head but to actually work it out in the real world i need help at this point the rest is easy. Im using just the pure natural weight of the water to turn the wheel.
5 Dia Wheel Wire spool
2.5 Radius
5 mph Stream
50 pounds of force on the wheel is not too unimaginable
15.707963267948966192313216916398 circumference
Since 5280 feet = 1 mile
5280/15.707963267948966192313216916398=336.13523981008294914388250824274=
1680.6761990504147457194125412137 RPH
28.011269984173579095323542353562 RPM
5.6022539968347158190647084707123 RPM = a 5 foot Dia wheel needs to turn about 5 RPM to reach 1 mph
28.011269984173579095323542353562 RPM to reach 5 Mile an Hour
125 pounds of torque = 50 x 2.5R
70 to 6 teeth 1:11.666666666666666666666666666667 (Bicycle Cog to Lawn mower sprocket)
28.011269984173579095323542353562 x 11= 308.12396982590937004855896588918
308.12396982590937004855896588918 RPM (Too low RPM)
70 to 6 teeth 1:11.666666666666666666666666666667 (Bicycle Cog to Lawn mower sprocket) again
3389.363668085003070534148624781 RPM
5.6818181818181818181818181818182 Pounds of torque If Torque is some what Hp relative, then
5 hp Minus the deficiencies of the RPM multiplier(s)
About 4,000 Watts
However, 3600 RPM is not needed (For 60cps) if a Car Alternator is used
Suggest; 800 RPM Field dependent (Stator) Low RPM is more efficient and less Cost
Also consider;
Alternator uses a electro magnetic field which is voltage variable = variable wattage output
Generator uses a perm magnetic field which is not variable = Wattage output is RPM dependent
Smaller the Wheel is the faster it will turn
Power (or wattage) is developed by Torque
When generating AC Power the only thing to consider in RPM is Cycles per second.
To get 60 CPS Most small AC Generators require 1800rpm and Lighter portables are 3600rpm
To get 80 hp my figures can be extrapolated
Ok, Guys, Sooooooooooo, I have a question;
Consider my above example; as a undershot five foot diameter Wheel, Dipped in a flow of water,
1 foot deep one center, one foot wide paddle and a five mile an hour flow of water.
Problem: With the exception, of load; Torque is not a constant.
Agreed we can improve efficiency, curve the buckets, Large diameter Low speed generator...
What would be the output (Wattage/Torque/Horse) Power for water speed of five Miles an hour flow?
Phil Bannon wrote:
Mac abees wrote:Ok here goes! I need to build an over shot water wheel, head does not matter, speed does not matter. All i need to figure out is how big, wide and deep a wheel I need to get at least 70 to 80 horse power at the shaft if some one can help me with that i can build a generator system anywhere. I will explain the rest after my patent lol. Eveyone one seems to be hooked on speed or rpms thats not what you need. The wheel should be at a snails pace but geared to spin a generator at 3600 rpm. Its right here in my head but to actually work it out in the real world i need help at this point the rest is easy. Im using just the pure natural weight of the water to turn the wheel.
5 Dia Wheel Wire spool
2.5 Radius
5 mph Stream
50 pounds of force on the wheel is not too unimaginable
15.707963267948966192313216916398 circumference
Since 5280 feet = 1 mile
5280/15.707963267948966192313216916398=336.13523981008294914388250824274=
1680.6761990504147457194125412137 RPH
28.011269984173579095323542353562 RPM
5.6022539968347158190647084707123 RPM = a 5 foot Dia wheel needs to turn about 5 RPM to reach 1 mph
28.011269984173579095323542353562 RPM to reach 5 Mile an Hour
125 pounds of torque = 50 x 2.5R
70 to 6 teeth 1:11.666666666666666666666666666667 (Bicycle Cog to Lawn mower sprocket)
28.011269984173579095323542353562 x 11= 308.12396982590937004855896588918
308.12396982590937004855896588918 RPM (Too low RPM)
70 to 6 teeth 1:11.666666666666666666666666666667 (Bicycle Cog to Lawn mower sprocket) again
3389.363668085003070534148624781 RPM
5.6818181818181818181818181818182 Pounds of torque If Torque is some what Hp relative, then
5 hp Minus the deficiencies of the RPM multiplier(s)
About 4,000 Watts
However, 3600 RPM is not needed (For 60cps) if a Car Alternator is used
Suggest; 800 RPM Field dependent (Stator) Low RPM is more efficient and less Cost
Also consider;
Alternator uses a electro magnetic field which is voltage variable = variable wattage output
Generator uses a perm magnetic field which is not variable = Wattage output is RPM dependent
Smaller the Wheel is the faster it will turn
Power (or wattage) is developed by Torque
When generating AC Power the only thing to consider in RPM is Cycles per second.
To get 60 CPS Most small AC Generators require 1800rpm and Lighter portables are 3600rpm
To get 80 hp my figures can be extrapolated
Ok, Guys, Sooooooooooo, I have a question;
Consider my above example; as a undershot five foot diameter Wheel, Dipped in a flow of water,
1 foot deep on center, one foot wide paddle and a five mile an hour flow of water.
Problem: With the exception, of load; Torque is not a constant.
Agreed we can improve efficiency, curve the buckets, Large diameter Low speed generator...
What would be the output (Wattage/Torque/Horse) Power for water speed of five Miles an hour flow?
Mac abees wrote:Ok here goes! I need to build an over shot water wheel, head does not matter, speed does not matter. All i need to figure out is how big, wide and deep a wheel I need to get at least 70 to 80 horse power at the shaft if some one can help me with that i can build a generator system anywhere. I will explain the rest after my patent lol. Eveyone one seems to be hooked on speed or rpms thats not what you need. The wheel should be at a snails pace but geared to spin a generator at 3600 rpm. Its right here in my head but to actually work it out in the real world i need help at this point the rest is easy. Im using just the pure natural weight of the water to turn the wheel.
Hello Mac,
A horsepower is x poundage weight per second (see web). A gallon of water weighs 10 pounds. The time of water weight being held is when the bucket is full to start of drain out.
Peter Mckinlay wrote:A horsepower is x poundage weight per second (see web). A gallon of water weighs 10 pounds. The time of water weight being held is when the bucket is full to start of drain out.
Peter, please note that a unit of mechanical power requires a length dimension (power being energy/work per unit time, and work being force times distance). That is, it's not merely weight per second, but weight (i.e. force) times distance per second (see web: http://en.wikipedia.org/wiki/Power_%28physics%29#Units). One horsepower is defined as 550 foot pounds per second.
Also, a gallon of water weighs about 8.33 pounds: http://www.engineeringtoolbox.com/watergallonspoundsd_1710.html.
Marcos Buenijo wrote:Peter, please note that a unit of mechanical power requires a length dimension (power being energy/work per unit time, and work being force times distance). That is, it's not merely weight per second, but weight (i.e. force) times distance per second (see web: http://en.wikipedia.org/wiki/Power_%28physics%29#Units). One horsepower is defined as 550 foot pounds per second.
Please note for clarification that when I write "energy/work per unit time", I mean energy (i.e. work) per unit time. That is, work is a form of energy. Specifically, in mechanical systems, it represents a transient energy where a force is transferred over a certain distance.
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