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The best way to get an advanced understanding of generating Micro-Hydro Electricity is to take an indepth look at all of the System Components- (or visit www.rockyhydro.com)
THE WATER INTAKE
The water intake is usually a scoop of some sort, or an open pipe just sitting in a stream with a screen over it. The picture is our favorite design, because it is self cleaning. And debis caught on the screen will simply be washed off.
PENSTOCK
The penstock is your water pipe that carries the water from the intake, down to your generator which is at a lower elevation. Having the correct type of penstock is crucial to any hydroelectric system. Because of the elevation drop, pressure will build in the pipe; but if the water flowing through the pipe experiences too much friction, the pressure decreases. You want to keep this decrease to a minimum.
Static pressure of the system is the pressure when there is no water movement. For every foot of elevation drop there is 0.433 PSI of pressure created. At a 50 foot elevation drop, your static pressure is 21.65 PSI. As water starts flowing through the pipe, your pressure will drop due to friction. The smaller the diameter of the pipe, the rougher the sides, the more joints, the more bends, and the longer the pipe, and the greater the flow of water will all decrease your pressure. Static pressure minus friction equals net pressure.
You want to keep your pressure loss to 8% or less. A larger pipe diameter is the easiest way to accomplish this. FSP has a calculater that calculates pressure loss based on multiple variables. Feel free to contact us at customersfirst@fsplimited.com with your site info (available gallons per minute, pipe lengh, and elevation drop) and we'll let you know how large of a pipe you will need to use to maximize your site's energy potential. Or just view or download the calculator HERE and you can figure it out yourself. In many cases, a smaller pipe can be used because the excess energy is simply not needed. 1" PVC pipe is dirt cheap and works great for a small system. However, using 2" PVC can almost double your energy in many situations....
WATER NOZZLE
The water nozzle is at the end of the penstock and can be as simple as a hole drilled in a pipe cap. The nozzle restricts the flow of water and makes it shoot out of the penstock where it can hit the turbine. The larger the nozzle allows for more water flow which creates more friction which reduces the net pressure. Ideally, your nozzle will be just large enough to allow for your site's available GPM, and your penstock will be large enough to handle this amount of water flow without causing too much friction.
TURBINE WHEEL
Now the water is shooting out of the nozzle and ready to hit a turbine wheel. In high head / low flow systems an impulse turbine such as a turgo or pelton wheel is used. In low head systems / high flow systems a reation turbine such as a propeller or impeller is used. In either case, the turbine takes the energy from the moving water and transfers it to a generator. FSP has chosen to use a turgo style turbine due to it's high efficiency. By directing the water backwards, it greatly increases the amount of force applied to the generator.
A turgo works most efficently when it is spinning at 48% of the velocity of the water jet. For this reason, FSP offers turgos of several sizes and diameters to help you achieve the perfect RPM. Again just email customersfirst@fsplimited.com and we will do our best to match your site to the perfect turgo.
GENERATOR
FSP has chosen the three-phase brushless dc motor for its generator due to its high efficency and durability. Brushes causes heat, noise, and sparks, all which equal energy loss. Plus, brushes are a major mechanical failpoint. Our brushless generators avoid all these problems.
Understanding the three phases can be tricky. Just imagine a magnet spinning inside the generator with the three wires spaced evenly on the outside radius. As the magnet spins, the flow of electricity will go from one wire to another, then change from one to another, then change again. So the polarity is constantly changing and can be graphed as shown.
Taking this energy and converting it to a nice smooth flow of DC power can be done with diodes and a capacitor. The diodes ensure that all the power only goes one direction. It doesn't restict any power, it only channels in to flow a certain way through the system. FSP uses special highly efficent diodes with fast reation times to ensure that virtually no energy is being wasted. The capacitor is different; it acts like a mini sponge in a sense. During peaks of power flow it will absorb the extra energy, then release it during the valleys, so the flow of electricty is smooth and continuous.
A generator needs to be carefully selected. If the turgo works best at 48% of the velocity of the water jet, then the generator needs to develop your sites energy potential at that RPM. Shoot us an email at customersfirst@fsplimited.com with your site info and we'll help you find the best turgo/generator combo if your site does not conform to our basic kit.
CHARGE CONTROLLER
A charge controller is the next peice of the system. A charge controller monitors battery power and will prevent the generator from overcharging the batteries. If the charge controller cuts the flow of electricty off, the generator will stop creating power, and with no resistance, the turgo will start to spin faster. For this reason, larger systems or systems where the turgo RPM may exceed the generator max RPM a diversion load controller may be needed. These can be spendy, so we encourage using a generator that can handle a high RPM and simply not running it all the time. This definetly makes since for remote cabins.
BATTERY
Connected to the charge controller is the batterie(s). Car batteries can be used, or deep cycle batteries, or the more spendy sealed gel batteries. Car batteries are fine for small systems not needing much storage. Deep cycle batteries are the most economical choice for greater storage, but need to be kept in a ventilated area because as they charge and discharge they do create fumes. Sealed gel or AGM batteries can be conviently stored inside and never need maintenance, but they do come with a price tag. If you need help finding batteries just send us an email and we can source some for you.
INVERTERS
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 and 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. FSP has several inverter options for sell with our basic kit, 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.
Confused? Here is a simple diagram of the electrical components that will hopefully help you to understand how everything is put together...
Ready to get started? Please see our Online Catalogue to order the basic kit, or you can email customersfirst@fsplimited.com with your site details so we can match the perfect turgo wheel and the perfect generator for your site, or download our hydro calculator in microsoft excel format so you can figure it out yourself. Or, to learn more about Micro-Hydro click on the following links-
PLEASE NOTE - ALASKA and INTERNATIONAL CUSTOMERS- PLEASE EMAIL customersfirst@fsplimited.com FOR A FREIGHT QUOTE BEFORE MAKING YOUR PURCHASE!
