Energy Systems & Design Easy Tune Stream Engine, Owner'S Manual, Page: 5 / 23

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The weir method is more versatile and may prove useful for higher flows. This technique uses a
rectangular opening cut in a board or piece of sheet metal set into the brook like a dam. The water is
channeled into the weir and the depth is measured from the top of a stake that is level with the edge of
the weir and several feet upstream. Looking at the chart that follows will enable you to convert the width
and depth of flowing water into gallons per minute.
Measuring the flow at different times of the year helps you estimate maximum and minimum usable
flows. If the water source is seasonally limited, you may have to depend on some other source of power
during dry times (solar, wind). Keep in mind that a reasonable amount of water must be left in the
stream (Don't take it all, that water supports life forms).
When head and flow are determined, the expected power output can be determined from the following
chart. Keep in mind that chart values represent
generated output and that actual power delivered to the
batteries will be reduced by transmission lines, power converters, and other equipment required by the
system. All systems should be carefully planned to maximize power output.
Stream Engine Output in Watts (Continuous)
Flow Rate
Liters/sec (Gallons/min)
Net Head
Meters Feet
0.67
(10) 1.33
(20) 2.50
(40) 5.00
(75) 6.67
(100) 7.50
(112) 9.50
(150)
3 10 - 20 40 75 100 130 150
6 20 15 40 80 150 200 250 350
15 49 45 100 200 375 500 650 800
30 98 80 200 400 750 1000 * *
60 197 150 400 800 1500 * * *
90 295 200 550 1200 * * * *
120 394 300 700 1500 * * * *
150 492 400 850 1900 * * * *
* In these higher output situations, it may be worthwhile to utilize more than one Stream Engine.