Your Waterwheel Solution
You need to determine how much power your site potentially might have.
To do this you will need to know two things, the quantity of water and the height of the water fall. From this you can determine the HorsePower at the axle of the waterwheel. One method to determine the quantity of water is to do a Weir Gate measurement. To use this method, click on the link for the Weir Gate Page. ** The height is the number of feet off the ground the water falls over the waterwheel.
** Weir gate numbers are in CuFt/Min. Remember to divide the number by 60 to get CuFt/sec. Then use the formula below to get your power number.
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HorsePower = Constant x Quantity x Height x Efficiency HP = Constant x (Cubic Ft / Sec of water) x (Height of Fall) x (Eff. of Wheel) |
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Waterwheel HorsePower @ Shaft 85% Eff Factor for the waterwheel |
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WaterWheel Diameter |
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Gallons
Per Minute
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Cubic
ft. per Sec
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10
Feet
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12
Feet
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15 Feet
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18 Feet
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20 Feet
|
|
100
|
.223
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.215
|
.258
|
.322
|
.387
|
.430
|
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200
|
.446
|
.430
|
.515
|
.644
|
.773
|
.859
|
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300
|
.668
|
.644
|
.773
|
.966
|
1.160
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1.289
|
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400
|
.891
|
.859
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1.031
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1.286
|
1.546
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1.718
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500
|
1.114
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1.074
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1.289
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1.611
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1.933
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2.148
|
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800
|
1.783
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1.718
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2.062
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2.577
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3.093
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3.436
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1000
|
2.228
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2.148
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2.577
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3.222
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3.866
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4.295
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1500
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3.342
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3.222
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3.866
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4.832
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5.799
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6.443
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2000
|
4.456
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4.295
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5.155
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6.443
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7.732
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8.591
|
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3000
|
6.68
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6.443
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7.732
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9.665
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11.598
|
12.886
|
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Example HorsePower for 800 gal/min @ 15 Feet ***** HorsePower = C* Q* H* E ***** C= Constant (See Below) Q= Quanity of water (for cu/ft/sec multiply gal/min by 0.002228 ) H= Distance over Waterwheeel E= Efficiency of the Wheel Efficiency of a Waterwheel .85 to .90 Metal Waterwheel .70 for a Wooden Waterwheel .60 Poncelet Waterwheel **************************************** HorsePower = .1134 * 1.783 * 15 * .85 HorsePower = 2.577 |
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Where did the constant come from Constant = (Water Weight lbs.) / (foot-lbs/sec) Constant = (62.42 / 550.221) Constant = 0.113491 |
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1 HorsePower = 746 Watts To get electricity out of a waterwheel you will have to gear the RPMs of the waterwheel up 300 to 600% and then run it through a generator or a DC motor to charge a battery bank. This will generally cut your power at the axle HP by almost 1/3 to 1/2. A waterwheel is really designed to do mechanical work Most homes require 4000 to 7000 watts of power for simple operations. |