Yes,    I make and sell  water wheel generators and gearing setups but first you need to do a little work learning how much water you have and how high up you can get it before you contact me.     I realize this may sound a little rough but every week I spend several hours on the phone and email with people with the dream of making power but no idea about their water flow and head so I can't even begin to help them.       Spencer                    

Ok,     so you might have a good hydro site and you would like to make a little electricity.       First off please realize that all man made systems are inefficient so it is impossible to make enough power to pump the water to make the wheel run on its own.      You must have an running stream to supply the power unless you are willing to pay for more electricity than you make.         This rule applies to any hydroelectric system on the planet.   

Now that we've got that fact straight we can get to the basics; how much water do you have and how much head (head is how high can you get the water) you have.      Higher head equals more potential energy.       Water flowing through a stream but has some power but if you can get the water up it has a lot more potential energy.     In addition to the increased potential energy (from the drop) a water wheel taking the water from over the top (Overshot wheels are about 80% efficient) is much more efficient @ converting the water's energy into usable power than a wheel that is being pushed by the water flowing under it (Undershot wheels are about 15% efficient).       So the more water you have and the higher you can get it the more electricity you can make.     Most people are surprised @ how much electricity we use everyday and how much water power it takes to make it so don't have unrealistic expectations; you're not going to supply a modern house from a small creek with a very small head although for many people just running the lighting around their garden or their shop is a source of pride and reduces greenhouse gasses protecting our environment.     

There are several ways you can measure your water flow yourself.       At the bottom of this web page is the easiest but least accurate method if you plan on only guessing what size pipe your water would fill and how fast it would flow through a smooth walled pipe.        More accurate methods are shown @ http://www.energybible.com/water_energy/measuring_flow.html

And some thoughts on how to measure your head here.   http://www.energybible.com/water_energy/measure_water_pressure.html

Calculate the potential power you have

Ok,      So now that you know how much water and how much head you have we can do some simple calculations to figure out how much power we can make.     

First a few facts to help you picture what these results mean.    

1 horsepower equals 746 watts of energy

A 60 watt lightbulb needs 60 watts of energy to light up

A LED bulb only needs about 2 watts to run

These numbers will help you picture what your calculations mean.      A well designed overshot water wheel is about 80% efficient @ converting the water's energy into torque @ the wheel's axle.      Since the wheel spins slow (7-10 rpm) and the alternator needs to spin fast you will need some gearing to speed things up.      In addition to this your alternator and charge controler aren't perfect either so between the gearing and the alternator you will loose an additional 25%-30% of your wheel's energy so...  total system efficiency will be around 55%.      When using the following formula if you use .80 for the efficiency you will be measuring the energy @ the wheel's axle.       If you use 55% for the efficiency you will get a realistic figure for how much electricity you will actually be producing.

The horsepower of your water wheel can be calculated by

# of gallons per minute   x     .000253     x     height in feet       x        Efficiency     =     Horsepower

So if you have 700 gallons per minute of flow and are using a 8' diamater water wheel and was looking to see how much electricity (55% total system efficiency) you could make it would look like this.

700  x  .000253  x  8  x  .55  =  .779 horsepower     

So if 1 hp is 746 watts you could say  .779  x  746  = 581 watts of electricity would be make by this water wheel which is enough to run nine 60 watt light bulbs for as long as the wheel is turning with a little power left over.

If you were more interested in the power @ the wheel's shaft and the wheel is 80% efficient it would look like this.

700  x  .000253  x  8  x  .80  =     1.13 hp

So if a hp is 746 watts       1.13 x 746 =  843 watts potential @ the wheel's axle.

A thought to help you understand

The constant (.000253) is the water weight in pounds divided by the foot pounds per minute.      The height is the water wheel diameter so if you have 9' of head but are only running a 6 foot diameter wheel the height for this calculation is 6 feet.          There are online calculators out there but they are usually in metric measurements but if you still want to try one here one is.      http://www.reuk.co.uk/Calculation-of-Hydro-Power.htm    This online  calculator figures the power output @ 60% efficiency so it may be a little optimistic.

Most people use 12v batteries to store their electricity and an inverter (available @ Radio Shack, local truck stops, or online) to make the power into 120v AC.      Since the batteries store up excess energy a water wheel making only 100 watts of electricity can run a 1200 watt microwave oven by using the energy stored over time in the batteries. 

So now you've got a water wheel how do you get the electricity?

After determining how much power your water wheel can make you need to find a low RPM alternator that is sized to maximize your electric output.      You need to design and build a strong gearing system that fits your alternator's RPM requirements while minimizing friction.      You will also need some batteries to store your power, how many and how big depends on how much electricity you are making and using.      12v deep cycle marine batteries work well for this and are available @ almost any auto part store.      Most low RPM alternators make power whether the batteries need it or not and will overcharge the battery if allowed to so...    You will need a charge controller designed for wind or hydro use.       The charge controller will send all of the power to the battery until the battery voltage reaches a set voltage (usually 13.6v).     After the batteries are fully charged the charge controller will send the extra power to a dummy load (usually an electric heater coil) which will harmlessly dissipate the extra energy as heat. 

The more gearing you use the more friction and less power so I recommend a low rpm alternator that will make power @ a lower speed instead of a inefficient car alternator which must run @ a much faster speed.      You will also want a charge controller designed for hydro or wind applications so that you don't overcharge your batteries.      Do not use a charge controller designed for solar applications,     due to their lower price they may look attractive but when you melt down your system using the wrong controller you'll wish you'd bought the better controler.

Want me to build a water wheel and matched generator package for you?     Let me know.

Spencer@waterwheelplace.com     706-207-1080

Assume Gravity Flow. About 6f/s flow velocity, Sch 40 Pipe Size ID (range) OD GPM (with minimal pressure loss & noise) GPH (with minimal pressure loss & noise) 1/2" .50-.60" .85" 7 gpm 420 gph 3/4" .75-.85" 1.06" 11 gpm 660 gph 1" 1.00-1.03" 1.33" 16 gpm 960 gph 1.25" 1.25-1.36" 1.67" 25 gpm 1,500 gph 1.5" 1.50-1.60" 1.90" 35 gpm 2100 gph 2" 1.95-2.05" 2.38" 55 gpm 3300 gph 2.5" 2.35-2.45" 2.89" 80 gpm 4800 gph 3" 2.90-3.05" 3.50" 140 gpm 8400 gph 4" 3.85-3.95" 4.50" 240 gpm 14,400 gph 5" 4.95-5.05" 5.563" 380 gpm 22,800 gph 6" 5.85-5.95" 6.61" 550 gpm 33,000 gph 8" 7.96" 8.625" 950 gpm 57,000 gph

GPM/GPH Flow based on PVC Pipe Size These figures assume that the water is flowing @ about 6 feet per second.      If you water is flowing @ only 3 feet per second you will have ½ the water amounts listed and if the water is flowing faster you will have more water.   In the chart to the left is a general guideline for how much liquid a pipe of specific size can flow in GPM (Gallons Per Minute) & GPH (Gallons Per Hour.)   This is a very general guide and is subject to many variables. Pressure, bends, fittings, viscosity, etc. affect how much liquid will flow through a pipe of given size.