RockyHydro - Affordable Custom Hydroelectric Systems
#1 Measure your FLOW
To get started, you first need to measure your gallons per minute. There are multiple ways to do this-
If your flow rate is relatively slow, you can measure the time it takes to fill a 5 gallon bucket. Once you have your seconds, you can calculate the gallons by taking 60 divided by your seconds, then multiply your answer by 5. For example, if it takes 25 seconds to fill the bucket, you do - 60 / 25=2.4 and then 2.4 x 5 = 12 gallons per minute. If it takes 4 seconds to fill the bucket, (60/4)x5=75 gallons per minute.
If your stream is larger, it may be better to make the measurement with a float. First find an area of the stream where the size and speed of the flow is as consistent as possible. Next, place a board across the stream with 1 foot intervals marked across it. Measure the depth of the stream at each interval and average them.
For example, if your measurements are 2 inches, 8 inches, 10 inches, 7 inches, and 4 inches, the average would be - (2+8+10+7+4) / 5 = 6.2 inches.
Now multiply this average depth by the width of the stream and you have the cross section. If our example is 60 inches wide, then the cross section would be 6.2x60=372 square inches.
There are 144 square inches in a square foot, so divide your square inches by 144 and you have square feet. 372/144 = 2.58 square feet.
Next find a good sized and weighted float. Something that is good sized and just barely floats will be much better than a balloon or a leaf that is just skimming the surface of the water. Mark a distance of the stream where you will be timing the float. Place the float upstream of this area to make sure it has a chance to accelerate to the speed of the stream before you start clocking it.
Take several measurements of the time it takes the float to travel the distance you marked out. Average them. Now you have the speed of the water. For example, if it took 5 seconds to travel 10 feet, the speed is 2 feet per second (10/5). Multiply this by 60 to get feet per minute. 2x60=120 feet per minute.
Multiply this again by your cross section, and you'll have cubic feet per minute - 120x2.58=309 cubic feet per minute.
There is 7.48 gallons in a cubic foot, so you can multiply this by your cubic feet per minute to get gallons per minute. 7.48x309= 2311 gallons per minute.
Because the water along the bottom of the stream will be flowing slower due to friction than the top of the stream, you can multiply this number by 80% to get a more accurate idea of your gallons per minute. 0.8x2311=1848 gallons per minute.
#2 Measure your HEAD
Your HEAD is the elevation drop that your stream does. The more head you have, the more pressure will build up in your penstock. The easiest way to measure head is to get a small pressure gauge from a hardware store and install it in the end of a hose. Simply place one end of the hose in the water at the source, and then run the hose down the hill to where your generator will be. Allow the hose to fill with water, then plug the hose so the entire weight of the water is pushing against the pressure gauge. Every 2.31 feet of elevation drop will produce 1 PSI, so you can multiply your PSI by 2.31 to get your elevation drop. For example, if you have 25 psi, your head will be 25x2.31=57.75 feet. While you're at it, watch the pressure gauge as you allow a little water to flow through the hose - the pressure will go down as you let more and more water flow through. This is the effect of penstock friction, as more water flows through the penstock, friction increases and pressure decreases. Gross or static pressure minus friction equals net pressure. Our calculator computes your net head and helps you determine how large of a pipe you'll need to minimize this friction.
Another way to measure head is simply with a level and a tape measure. This method is self explanatory by the picture.
#3 Measure your penstock lengh
This one is simple! Just grab a tape measure and figure out the distance from your water source to where the generator will be.
#4 Put it all together!
If you multiply the head in feet by the flow in gallons per minute, then divide by 10, you'll know the watts that you can potentially produce.
#5 Decide on the extras....
If you are charging a battery system, you'll want to have a charge controller. Depending on the size of you system, you may opt for a simple controller or a more expensive and advanced diversion load controller.
If you're charging batteries, you'll also need an inverter to change the low voltage DC battery power to high voltage AC power that your home appliances use. Inverts change the 12 volts of DC power to 120 volts of AC power used by common household appliances. Some inverters are better than others. For small systems, a modified sine wave inverter can be used. These are the most popular, least expensive, and run most equipment. Pure or True sine wave inverters are more expensive, but can run anything. They actually can produce power that is cleaner and crisper in a sense than what you get from the utility company. Modified sine wave power should be fine for radios, fans, most tools, or anything that has it's own battery like a portable DVD player or a laptop. You'll be able to charge a cell phone just fine. RockyHydro has several inverter options for sale, or send us an email and we can provide you with a quote for whatever your needs are. If you're planning on hooking up an Xbox to a Plasma TV you'll want to invest in the true sine wave inverter.
Ready to proceed? Click on the "Buy Now" button below to pay a $50 fee and you'll recieve-
A Micro-Hydro Calculator - used to calculate:
Power or watts your stream can produce
Necessary pipe diameter for your penstock (based on Hazen-Williams pipe-friction formulas)
Amount of money you'll save by generating your own electricity
Number and size of nozzles
Nozzle angle and placement
Supplier Lists - For direct purchasing of generators, turbines, rectifiers, charge controllers, and inverters. We'll you provide you with their websites, and other contact info so you can make all your purchases without a middle man!
Personal contact information - With this you can provide us with your head or elevation drop, flow, and pipe length. We'll provide you with unbiased, honest information about which generator and turbine would work the best, and give you a recommendation on pipe size so you can get the most power out of your site!
A Downloadable Contruction Manual - Concerning how to put your complete system together, from the penstock to the generator and turbines with charge controllers and inverters.