We offer a variety of small hydroelectric generators that are designed to be 12, 24, or 48 volt battery chargers, operating off a relatively small volume of water. They charge batteries 24 hours per day and the power can be drawn from the battery as needed. As little as 100 gallons per minute (GPM) falling 10 feet through a pipe or 5 gallons per minute falling 200 feet through a pipe can supply enough power to comfortably run a small household. In areas where there is a long rainy season, and there is a mountain stream that can be used, a small hydroelectric system can work well with solar modules, both charging the same battery. When it is rainy and the solar modules are putting out less power, the hydroelectric system will be at its peak.

By contrast, typical AC power hydroelectric systems, designed to deliver ready-to-use 120/240 VAC power, are not practical for most people because they need a constant water supply large enough to supply the peak power output that will be required, usually a minimum of several thousand watts, requiring hundreds or even thousands of gallons per minute, depending upon the pressure available. Besides requiring large amounts of water, these turbines require large pipe diameters and expensive regulating systems that can maintain proper frequency and voltage at all times.

How much power can you generate?

The amount of power available depends on the dynamic head, the amount of water flow and the efficiency of the turbine/generator combination. To get an idea about available power in watts, multiply the head in feet, times flow in GPM, times 0.18 times efficiency. Turbine efficiency ranges from 25% to 50%, with higher efficiency at higher heads. To get a rough idea, use 0.30 (representing 30%) as a multiplier for efficiency.

Pipelines

A hydroelectric turbine operates from the pressure at the bottom end of a pipeline. This pressure, usually measured in pounds per square inch (PSI) is directly related to the head, or vertical distance from where the water goes into the pipe at the top of the pipeline, to the turbine located at the bottom of the pipeline. The pressure at the lowest point of a pipeline is equal to 0.433 times the vertical distance in feet, called head. Pressure is important because it is a determining factor in how much power is available and in what type of pipe is required. Polyethylene pipe can be used for pressures up to 100 PSI, PVC pipe is available with pressure ratings from 160 to 350 PSI and steel pipe can withstand 1000 PSI or more. Check with you local plumbing supplier for pipe ratings.

Pipe diameter is very important. All pipelines will cause the water flowing in them to lose some energy to friction. The pipe must be large enough for the maximum quantity of water it will carry. The pressure at the bottom of a pipeline when water is not flowing is called static pressure. When water is flowing through the outlet or nozzle of the hydroelectric turbine, the pressure at the outlet is the dynamic pressure or running head.

If you install a gate valve on the pipeline just above the turbine and a pressure gauge on a "T" fitting just above the gate valve, you will read the static pressure on the gauge when the valve is closed and the dynamic pressure when the valve is opened. The maximum power that can be delivered by a pipeline will occur when the dynamic pressure is approximately 2/3 of the static pressure. The actual flow rate of the water in a hydroelectric system is determined by the diameter of the nozzle. We will supply a turbine with the proper size nozzle for your site, depending on the head, flow and length and diameter of the pipe.

We carry hydroelectric generators made by Energy Systems and Design and the Harris Hydroelectric company. Use the descriptions on the product pages to help determine which turbine will work best for your site and power requirements.

Let us help you design the system

If you think you have a suitable site, call us or write to us and we can help you determine the best unit for the situation. Determine the following information about your site before you contact us:

1. Head - The total vertical elevation from the place where the water enters the pipe to the point where the turbine will be located.
2. Flow - The number of gallons per minute that are available.
3. Distance - The length of pipe that will be necessary to carry the water from the pickup to the turbine. If the pipe is already installed, what is the type and diameter?
4. Location - Distance from turbine to batteries.

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